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, doi: 10.14133/j.cnki.1008-9357
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$v.latestStateEn , doi: 10.14135/j.cnki.1006-3080.20190307001 [Abstract](971) [FullText HTML](252) [PDF 1116KB](13) Articles in press have been peer-reviewed and accepted, which are not yet assigned to volumes/issues, but are citable by Digital Object Identifier (DOI). Display Method: [Abstract](0) [FullText HTML](0) [PDF 0KB](0) Abstract: Ranpirnase, as a multi-functional protein drug, is one of many drugs that being studied all over the world. it was first isolated from the oocytes and early embryos of Northern Leopard Frog, and belongs to the ribonuclease A (RNase A) superfamily. Ranpirnase can not only inhibit protein biosynthesis pathway, but also independently induce tumor cell apoptosis. it not only has anti-tumor effect, but also has antiviral activity. In this study, In order to improve the expression level of ranpirnase in E. coli. Plackett-Burman (PB) experimental design was applied to investigate the effect of various factors on onconase expression in recombinant E. coli and optimize recombinant E. coli fermentation medium and inducing conditions. On the basis of these results, the onconase expression in recombinant E. coli was carried out in 7 L fermentor with the combined exponential and pH-Stat feeding strategy. Finally, using the optimized fermentation medium, the protein expression at flask level was increased from 9% to 36%, OD600 value was from 4.8 up to 5.47. Expression of oncanase at 7 L fermentor level was reached to 55%, OD600 value was increased to 35 after the optimization.The use of optimized medium for high-density fermentation of ranpirnase further saved the production cost and accelerated the marketization of ranpirnase. [Abstract](1953) [FullText HTML](524) [PDF 1424KB](10) Abstract: Chronic cerebral hypoperfusion (CCH) is one of the most important causes in the initiation and progression of vascular dementia. Tanshinone IIA (TSA) is an active compound isolated from the plant roots of Salvia Miltiorrhiza, which is a traditional Chinese medicine with the activities of improving blood circulation and reducing vessel stasis. In this study, the potential neuroprotective effects and mechanisms of TSA were studied using a bilateral common carotid artery occlusion (BCCAO) model in vivo and H2O2 induced oxidative damage of primary astrocytes in vitro. The results showed, first of all, TSA obviously reversed BCCAO induced cognitive impairment in rats evaluated by Morris water maze (MWM). Nissl staining showed the neuronal loss in CA1 and CA3 region were reversed by TSA. TSA also increased the expression of brain-derived neurotrophic factor (BDNF) levels in cortex and hippocampus. In H2O2-induced primary astrocytes injury, TSA suppressed the decrease of cell viability and inhibited lactate dehydrogenase (LDH) release. Secondly, TSA attenuated mitochondrial membrane potential (MMP) loss and increased ATP level. Furthermore, TSA significantly reversed the damage induced by the disorders of the mitochondria respiratory complex enzyme, and then attenuated reactive oxygen species (ROS) accumulation and lipid peroxidation, simultaneously enhanced antioxidant capacity. The results demonstrated that TSA could enhance mitochondrial bioenergetics and ameliorate oxidative stress effectively, which might contribute to the improving effect of TSA on cerebral ischemia, hypoperfusion and oxidative injuries. Our study provided new evidence to illustrate the mechanisms of protective effects of TSA on cerebral ischemia induced cognitive impairment. [Abstract](2) [FullText HTML](3) [PDF 849KB](0) Abstract: Modified activated carbon was prepared by stepwise composite modification with oxidant and nucleophilic addition reagent. The specific surface area and pore structure of activated carbon were measured by N2 adsorption-desorption (BET). Formaldehyde was used as a model pollutant to test the purification performance of modified activated carbon. The results showed that the stepwise composite modification, first with the oxidant then with the nucleophilic addition reagent, could significantly improve the fast purification efficiency of activated carbon for formaldehyde. While the stepwise composite modification, first with the nucleophilic addition reagent then with the oxidant, showed excellent long-term purification effect. After the activated carbon was impregnated first with 2-imidazolidinone and then with sodium hypochlorite in a stepwise composite modification, the long-term purification efficiency of formaldehyde with coconut shell and coal-based activated carbon reached 94.2% and 96.2%, respectively. [Abstract](44) [FullText HTML](30) [PDF 873KB](2) Abstract: A nanopesticide has been increasingly favored due to its small particle size, high biological efficacy, and good dispersibility. However, a nanopesticide typically has a high price since of its costly production, which limits its applications in many cost-sensitive agricultural areas. Aligned with the national policy of the dosage reduction and efficacy enhancement of agrochemicals, a nanopesicide has very promising and demanded applications. This review introduces a new technology, capable of highly effective production of an aqueous nanodispersion with an ultra-high load of a pesticide, the flash nanoformation (FNF) technology, which is expected to be able to realize massive production of nanopesticides in a fast and economical way. [Abstract](6) [FullText HTML](5) [PDF 867KB](0) Abstract: Water-soluble fluorescent probes have been developed and applied in physiological environments for biomedical science applications. Such probe molecules require good water-solubility, and the introduction of water-soluble substituents on conventional organic fluorophoreshas brought challenge about the preparation, separation, and purification processes. In this paper, probe molecules (36 and 9) based on naphthalene anhydride derived on rigid spiro-bifluorene skeleton were designed and synthesized. By converting commonly used naphthalenedimide functionality to anhydride groups, we were able to hydrolyzethe of acid anhydride groups under alkaline conditions, into a charged carboxylate structure to improve the water solubility of the probe molecule. At the same time, the solubility of the acid anhydride group in common organic solvents facilitates the separation and purification of the compound. UV-vis absorption spectra of a probe molecule in water upon increasing pH value, displayed hyposchromic-shift in absorption and increased solubility, implying the naphthalic anhydride group of the probe has been converted to carboxylate, which makes the probe good water-soluble to facilitate imaging. Probes 369 were successfully stained in cell imaging, effectively eliminating background signal interference. This result suggested that our strategy is promising for developing water-soluble fluorescent probes. [Abstract](538) [FullText HTML](267) [PDF 1472KB](3) Abstract: Both inorganic and organic pollutants in water result in damages on the ecosystem due to their toxicity and consumption of dissolved oxygen in the water. Adsorption separation has been regarded as one of the most widely used wastewater treatment methods because of its easy operation, low cost and recyclability. Cyclodextrin (CD) is a commonly used adsorbent material because of its ability for encapsulating of hydrophobic molecules, but its water solubility and low adsorption capacity limit its applications. Here, three different diisocyanates (hexamethylene diisocyanate HDI、1,4-Phenylene diisocyanate PDI、Diphenyl-methane-diisocyanate MDI) were selected as cross-linking agents to synthesize three CD-polyurethane composites (CD-HDI,CD-PDI,CD-MDI) with different structures. SEM, FT-IR, TG and UV-vis spectroscopy were employed to characterize the synthesized composites. The adsorption kinetic mechanism was studied by using pseudo-first-order model and pseudo-second-order model. The results showed that the pseudo-second-order model fitted better than the pseudo-first-order model, indicating that the adsorptions of the adsorbent against BPA and MB are chemisorption process. To study the adsorption mechanisms of CD-HDI, CD-PDI, CD-MDI toward different pollutants, three different models were applied to fit the equilibrium adsorption data. The results indicated that Sips model described the adsorption performances for BPA and MB very well, and the maximum adsorption capacity was 65.3—116 mg/g for BPA and 8.90—26.5 mg/g for MB, respectively. The removal efficiency of BPA and MB by the adsorbent decreased by 0.8%—2.4% for BPA and 7.6%—13.4% for MB after 5 cycles, respectively, indicating the good recyclability of the adsorbent. [Abstract](1982) [FullText HTML](713) [PDF 803KB](17) Abstract: It is usually assumed in flow shop scheduling problem that all of the processing procedures are performed in one factory, which is termed as single factory production mode. Nowadays, the distributed manufacturing, due to its low cost, low risk, and high quality, has been becoming the main development trend in the industrial production. Therefore, it is necessary to study the distributed scheduling problem. The distributed assembly permutation flow shop scheduling problem plays an important role in modern supply chains and manufacturing systems. In this paper, a modified biogeography-based optimization (MBBO) algorithm is proposed for solving distributed assembly permutation flow shop scheduling problem to achieve the goal of minimizing makespan. In the initialization phase, the proposed MBBO uses the SPT and the NR2 rules to optimize the feasible solutions. Then, in the mutation phase, the job insertion heuristic method based on the factory completion time is used to adjust the factory assigning and the processing order of the jobs. Moreover, the simulated annealing algorithm is combined to avoid the local optimal solutions and enhances the global search ability. Finally, simulation experiments are made via 900 small instances and 540 large instances, and the comparison is provided with the existing 12 heuristic and metaheuristic algorithms as well as the basic biogeography-based optimization algorithm. These above results verify the superiority of the proposed MBBO. Meanwhile, the new best known solutions for 70 instances are found. [Abstract](1438) [FullText HTML](695) [PDF 857KB](11) Abstract: Traditional optimization methods, such as simplex method, steepest descent method, and conjugate gradient method, have the advantages of high computational efficiency, strong reliability, and mature theory, but it is difficult for them to solve the optimization problem without mathematical model. Moreover, for many high-dimensional optimization problems, they easily fall into the local minimum. Due to the characteristics of strong nonlinearity, high dimension, long computation time, and high precision, the parameters identification problem of the first-order reaction equation in Kumar model cannot be solved effectively by means of traditional optimization algorithm. In recent years, various stochastic optimization algorithms have rapidly developed, such as, genetic algorithm and differential evolution algorithm. Among them, differential evolution algorithm(DE) shows the strong ability to nonlinear optimization problem, due to its advantages of fast convergence, few control parameters, and simple parameter setting principle. Nevertheless, the standard DE algorithm and its improved algorithm have some shortcomings, e.g., slower convergence speed, easy falling into the local minimum, etc. Aiming at the above problems, this paper proposes a new classification variation parameter adaptive differential evolution algorithm (CVPADE). By combining the classification variation strategy with the control parameter adaptive evolution strategy, CVPADE algorithm can not only increase the convergence speed, but also avoid the shortcoming that the population diversity is not rich enough due to the small population size. Besides, the adaptive evolution strategy of parameters is controlled to make the algorithm more stable and avoid falling into local minimization. This can effectively solve the selectivity coefficient identification problem of Kumar model primary equation. Finally, the comparison with the standard differential evolution algorithm and the control parameter adaptive differential evolution algorithm (jDE) are made, showing that the time consumption of the proposed algorithm in this paper is 40% and 35% lower than that of DE and jDE, respectively. Hence, the proposed algorithm has a significant improvement effect on the parameter identification of the first-order reaction equation in Kumar model. [Abstract](311) [FullText HTML](251) [PDF 987KB](3) Abstract: Aiming at the problem of performance degradation after the upgrade of telecommunication systems, a cross correlation function-partial least squares (CCF-PLS) method is proposed to monitor the system performance and find the variables that results in the performance degradation. For the telecommunication systems with large sampling interval and strong linearity, the PLS model can well establish the regression model between key performance indicator (KPI) and other observation variables. Although the observation variables have many uncorrelated components with KPI, CCF can select those variables that are strongly related with KPI and can thus constitute a pre-processing procedure for PLS. Furthermore, by combing the contribution plot method, the CCF-PLS method can give the root cause of system abnormality. Finally, it is shown via simulation results that the method proposed in this paper can attain good practical effect. [Abstract](382) [FullText HTML](294) [PDF 1090KB](4) Abstract: Compared with continuous process, batch process is an important industrial production mode with more flexibility. Products from each batch depend on market demands, which will make the process switch between different product stations. So, the final quality of products may become unstable due to various composition of raw materials. This kind of uncertainty brings great challenge to process modeling. Aiming at the problem of raw material uncertainty and the requirement of actual predicted value, the loss function of bidirectional gated recurrent unit neural network is modified, and then, utilized to predict the final quality prediction of unequal-length batch processes. The bidirectional gated recurrent unit neural network can integrate the time series information of the batch data, and fully exploit the inter-batch timing characteristics caused by the uncertainty of the raw materials. The improved loss function imposes different penalties on different predicted values such that the predicted values can meet the requirements in actual production. Finally, the proposed method is compared with multiple partial least squares (MPLS), neural network (NN), support vector regression (SVR) and gated recurrent unit (GRU) via an industrial process. It is shown via the results that the proposed method has better applicability and performs higher accuracy. [Abstract](316) [FullText HTML](204) [PDF 895KB](13) Abstract: Attackers use software vulnerabilities to hijack the execution flow of the program, direct it to the malicious code or instructions that compose the malicious code, and finally achieve the purpose of controlling the behavior of the entire system. This kind of malicious attack is called control flow attack. Based on research of the principle of control flow attack, this paper propose a method based on the return address signature to detect control flow attack. The scheme firstly triggers pseudo random number generator to generate the key K to perform XOR encrypt operation with the return address that push into stack when the processor executes the call instruction, and uses the MD5 algorithm to generate the signature for the encrypted return address; Then, when processor executes the ret instruction, uses the MD5 algorithm to generate the signature for the encrypted return address that poped from stack. Finally, control flow attack can be detected according to whether the push_address signature matches the pop address signature. The experimental results show that the return address signature has good randomness and the control flow instruction that can be used to hijack the control flow is reduced to 81.27%, which can effectively prevent control flow attacks caused by maliciously tampering of the return address. [Abstract](726) [FullText HTML](326) [PDF 872KB](3) Abstract: A Mach-Zehnder interferometer demodulation scheme based on slow light in electromagnetically induced transparency medium is proposed and applied to improve the sensing sensitivity of fiber Bragg grating strain sensors. Theoretical studies have found that higher group refractive index can be obtained under suitable control field conditions by the common Λ-type three-level atomic system, and the sensing sensitivity of fiber Bragg grating strain sensors is improved. Influences of the control field on the sensing range and sensing sensitivity are further analyzed. According to the theoretical calculation, when the control field G=60 MHz, the sensitivity of fiber Bragg grating strain sensor based on Mach-Zehnder interference demodulation can be increased by about 3 000 times. The proposed strain sensor demonstrates a high sensitivity of −40 Rad/uε and strain measurement range of −50~50 nε. [Abstract](7667) [FullText HTML](2260) [PDF 1126KB](7) Abstract: In this study, a bacterial strain named 206BP, with efficient degradation for the organic matters in shale gas produced water, was isolated from high-salt wastewater and surrounding soil samples. Morphological observation, gram stain and 16SrDNA gene sequence analysis were used to identify the strain 206BP and the results showed that it belonged to the Bacillus genus as it had 99% similarity with Bacillus purgationiresistens and other orthologs. The diameters of the strain and spore were about 2.0 μm and 0.3—0.6 μm, respectively. Besides, it was confirmed that the strain was Gram-positive, capable of producing urease for urealysisand hydrogen sulfide gas as well as hydrolyzing starch and reducing nitrate and nitrite. The growth of the strain 206BP was observed that it stayed at the lag phase in the first 5 h and entered the exponential growth phase in the period of 5—22 h, finally reaching the stationary phase after 24 h. Meanwhile, the effects of NaCl concentration, carbon source, nitrogen source and pH on the growth characteristics were also investigated. The experimental results reflected that the strain 206BP could grow well and was moderately salt-tolerant with 0—8% NaCl. In addition, its optimum growth pH was in the range of 5—8 and the optimum carbon and nitrogen sources were glucose and urea, respectively. The bacterial concentration in the stationary phase of the growth curve could increase with the concentration of glucose while the stagnation period of the growth curve was prolonged as the glucose concentration exceeded 5 000 mg/L. The added urea had a positive correlation with the strain 206BP growth but the promotion faded away with the urea concentration up to 50 mg/L. [Abstract](5717) [FullText HTML](965) [PDF 600KB](7) Abstract: In parallel system, the arrangement graphs An,k has good properties such as symmetry, small diameter, and high fault tolerance. Subsystem reliability is defined as the probability that there is still a normal operating subsystem when the system has faults. It is usually used to measure the system health status, and the calculation of subsystem reliability is an NP-hard problem. This paper discusses the robustness of the reliability of the subgraphs and the approximate algorithm of reliability. Further, the Monte Carlo algorithm for arrangement graphs is constructed. The simulation results show that the constructed Monte Carlo algorithm is much better than the known approximation algorithm. In particular, the error of Monte Carlo approximation of A3,2 subgraph reliability is less than 1%. [Abstract](830) [FullText HTML](405) [PDF 757KB](1) Abstract: A defense method for linear deception attacks using KL divergence detector to detect watermarks in cyber physics system (CPS) is proposed. It is well known that linear deception attacks can degrade the performance of the remote estimator without being detected by the KL divergence detector. In order to detect such attacks, computer-based encryption methods use watermarks to encrypt and decrypt data transmitted over a wireless network to protect the system. In the absence of attack, the decryption section can recover the transmitted data to ensure remote estimation performance. In the case of linear deception attacks, these data will be watermarked to expand the variance of the transmitted data, so that the data at the receiving end will no longer obey the original normal distribution. Due to the convex nature of KL divergence, the KL divergence value can be proved. It is enlarged to exceed the thresholds that have been tested by the detector, so that they can help the KL divergence detector to detect the attack. The watermark encryption method has been proved to help the KL divergence detector to detect attacks or to mitigate the effects of attacks in different situations, and further discusses how to select the appropriate value of the watermark parameters, which makes the system’s protection performance more perfect. Finally, numerical simulations are given to further illustrate the limitations of the presence of watermarks on attackers, further highlighting the practical effects of parameter selection. [Abstract](2516) [FullText HTML](1196) [PDF 1011KB](67) Abstract: Hypervolume-based evolutionary algorithms can effectively solve the multi-objective optimization problem and obtain promising solution sets with fast convergence and uniform distribution. However, this kind of algorithms have higher computational complexity and lower programming efficiency. Aiming at the two-dimensional and three-dimensional multi-objective optimization problems, this paper proposes a hypervolume-based multi-objective evolutionary algorithm (MOEA-HV) so that the individuals’ exclusive hypervolume contributions can be accurately calculated to guide the evolution of the whole population. Before the indicator-based evolutionary algorithm(IBEA) is utilized, the proposed algorithm employs non-dominated sorting among all individuals to delete dominated individuals so that the amount of calculation of the individuals’ exclusive hypervolume contributions can be reduced and the operational efficiency can be improved. Meanwhile, other strategies in NSGA-Ⅲ are utilized to optimize the distribution of the proposed algorithm. It is shown via the experiment results that the proposed MOEA-HV has higher efficiency while maintaining the trade-off between the fast convergence and the uniform distribution.. [Abstract](35) [FullText HTML](19) [PDF 1099KB](1) Abstract: Regulating valve for pulverized coal is a key device to control and regulate the mass flow rate of pulverized coal in the coal gasification process. The study of the internal flow field characteristics has an important influence on the structure design and process operation control of the regulating valve. The gas-solid two-phase flow through the regulating valve for pulverized coal were studied by numerical approach of computational particle fluid dynamic (CPFD). First, a three-dimensional model of regulating valve for pulverized coal with 1000 mm length downstream pipe was established and validated with date from industry. The results of comparisons of pressure drop of regulating valve, particle velocity and particle mass concentration suggest that the CPFD method is suitable for the study of pneumatic conveying system with complex flow channels on an industrial scale. Then a logic model coupled CPFD method was proposed to calculate the mass flow rate of pulverized coal under different opening degrees. The mass flow rates of pulverized coal ranging from 10% opening to 40% opening were predicted correctly with error less than 10%. The result can be served as a reference for industrial operation of regulating valve for pulverized coal. Finally, the flow characteristics along the valve various opening degrees were investigated to obtain the distribution of pressure, particle velocity and particle volume fraction. Based on the analyses of the flow characteristics along the valve, the gas-solid two-phase flow reached a steady flow at about 800 mm of the downstream pipe. [Abstract](1983) [FullText HTML](584) [PDF 1143KB](4) Abstract: Blade-type multiply circular gas jets can be utilized for intensive cooling within limited area.The effects of impingement height H and jet Reynolds numbers on the heat transfer when multiply intensive circular air jets normally impinge on a smooth and flat surface are investigated experimentally. The average convective heat transfer coefficients are measured with heated thin foil technique which involves the detection of surface temperature and apples const heat flux heating. The jet Reynolds numbers ReD, vary from 5 000 to 48 500 and normalized impingement height H/D is in range of 6.25 to 12.5. The experimental results show that an increase in jet Reynolds numbers will produce higher average Nusselt numbers, and normalized impingement height with an exponent of −0.606 also have a strong impact on it. The experiment results are compared with Martin’s correlation and about 40% higher is observed. It is indicated that intensive circular nozzle array can significantly enhance heat transfer rate due to its high open porosity. The experimental data are quite well fitted by the Gardon's equation. Conversely the correlation proposed by Martin is not suitable to reduce present data and a modified geometrical function is developed. [Abstract](2019) [FullText HTML](583) [PDF 793KB](3) Abstract: By using a hyphenated solid phase extraction (SPE) and solid phase spectroscopy designed by our group, a rapid, sensitive and selective method for detecting Hg2+ in river water is developed. Hg-Dithizone produced with dithizone and Hg2+ can be enriched on a mixed cellulose membrane, and the residual dithizone was removed by washing the membrane with sodium hydroxide solution. Then, visible diffuse reflectance spectroscopy was used for the quantitative analysis of mercury ions in situ. As such, unwanted interference from other contaminants was minimized by washing the membrane to remove dithizone; EDTA is also added to mask Cu2+ and Cd2+. Under the optimal conditions, the liner range of the method is 0.5−30 μg/L with a squared correlation coefficient of 0.993, and the limit of detection is 0.444 μg/L. The method is applied to the quantification of Hg2+ in tap-water and river water samples, respectively. The recovery rates achieve 91.3% to 108.0%, and the relative standard deviations of parallel tests are between 2.06% and 9.68%. This work offers a fast method for the determination of Hg2+ in river water samples with high sensitivity and selectivity. [Abstract](2350) [FullText HTML](996) [PDF 951KB](22) Abstract: Aiming at the shortcoming that there exist too many channels in motor imagery (MI)-based brain-computer interface (BCI) systems, this paper proposes a channel selection algorithm based on multi-correlation forward searching (MCFS) algorithm such that the performance of BCI systems can be improved via the optimized the channel set. First, a forward searching algorithm is performed on the channel set via the training set. Meanwhile, the trust values of three correlation algorithms are updated with the classification accuracy of the validating set. Then, according to the above trust values, the high-quality channel set is selected, the common spatial pattern (CSP) algorithm is adopted to obtain the motor imagery related features, and the classification model is trained by means of support vector machine (SVM) with a linear kernel. Finally, the proposed algorithm is implemented on two datasets (BCI competition IV dataset I and BCI competition III datasets IVa), by which the average classification accuracy 81% and 87% are achieved, respectively. Moreover, compared with three other common channel selection algorithms, the proposed MCFS algorithm obtains the highest average classification accuracy. These results show that the proposed MCFS algorithm has superior performance and provides a technical reference for the application of MI-based BCI system. . [Abstract](2160) [FullText HTML](713) [PDF 849KB](14) Abstract: Dividing wall column has the advantage of energy saving and low capital cost compared to the conventional rectifying column. While this method is more flexible than the conventional rectifying column, its control and optimization are more difficult. In this paper, we address the shortcomings of existing dividing wall column methods by introducing an improved calculation method. The minimum operating conditions of the dividing wall column are determined according to the Underwood equation, and the operating parameters such as the number of stages, the feeding stage, side-stream stage, the reflux ratio, and the gas-liquid distribution ratio of the dividing wall column can be quickly determined in combination with design requirements. To verify the effectiveness of the design method, three different ESI (Ease of separabjlity Index) feed streams are selected, and the results are strictly simulated in HYSYS. The results show that our method is more accurate than previous methods in calculating the composition of the connecting stream between the pre-fractionator and the main column, and the total annual cost is lower. [Abstract](1191) [FullText HTML](393) [PDF 771KB](6) Abstract: A polynomial-time topological reduction plays an important role in the computation of diameter constrained reliability, because many irrelevant edges are able to be deleted and the reliability remains unchanged. However, irrelevant edges cannot be completely found from previous researches. The necessary condition of detecting irrelevant edges is a so-called open problem. In this paper, we define new metrics of path lengths, classify st-paths as real path (RP), pseudo path (PP), combination path (CP) and the shortest st-path containing a specific edge (SPE), and make it clear that the length of SPE can be approached by measuring PPs, RPs and CPs. Further, we propose an algorithm to detect innermost irrelevant edges and the complexity of the algorithm is polynomial (O(n4)). Experiment results show the effectiveness and efficiency of the algorithm. [Abstract](547) [FullText HTML](251) [PDF 1118KB](1) Abstract: To reduce the harm of cigarette smoke to health has been widely investigated in the cigarette industry. The tobacco burning or heating mode has a great impact on the released harmful components. Much work has been made to develop the new cigarette-heat product with the aim to decrease the amount of the harmful components from the smoke. In order to investigate and understand the characteristics of tobacco heating by the cigarette-heat product, smoke flow state and heat transfer process during the smoking mode, a three dimensional mathematical model of porous medium for tobacco heating and smoke flow in a cigarette was established. The process of heat transfer and flow were numerically simulated using computational fluid method (CFD) software (ANSYS Fluent). The flied distribution of temperature, velocity and pressure during cigarette heating by the heater of cigarette-heat product and smoking at a constant flow rate were obtained. The results showed that the tobacco could be effectively heated to 493.6 K by the heater for cigarette-heat product with a total heat transfer coefficient of 3.4 W/(m·K). During smoking at a constant flow rate of 17.5 mL/s, the tobacco temperature was decreased from 394.1 K to 393.8 K with a uniform radial temperature distribution, and the smoke flow hasd a relatively small impact on temperature distribution of the tobacco. On the other hand, the pressure was decreased from the tobacco section to holder. These results can provide the theory guidance and fundamental data for optimizing the structure of the cigarette-heat product and the heating mode of tobacco to a certain extent. [Abstract](54) [FullText HTML](28) [PDF 1126KB](1) Abstract: Oligo-1,6-glucosidase (EC 3.2.1.10) showed a good activity for the utilization of isomaltose in the residual sugar of lactic acid fermentation broth. Based on the previous research work and approved by BRENDA database search, five possible heat-resistant and acid-resistant oligo-1,6-glucosidase enzyme genes (Bacillus coagulans ATCC 7050: malL BF29_2011(BC1) and malL BF29_2004(BC2); Bacillus subtilis 168: yvdL BSU34560(BS1) and yugT BSU31290(BS2); Bacillus thermoglucosidasius KP 1006: malL(KP)) were selected for the research of recombinant expression in E. coli, purification and enzymatic properties of these oligo-1,6-glucosidases. The optimal pH of BC1, BC2 and KP was 5.0, and that of BS1 and BS2 was 6.0. The optimal temperature of these five oligo-1,6-glucosidases from high to low was KP (60 ℃) > BC1 (56 ℃) = BC2 (56 ℃) > BS1 (43 ℃) = BS2 (43 ℃). In addition, Mg2+ and \begin{document}${\rm{NH}}_4^ + $\end{document} could enhance the enzyme activity of BC1, while Co2+, K+, \begin{document}${\rm{NH}}_4^ + $\end{document} could enhance the enzyme activity of KP. However, these ions had no obvious activating effect on BC2, BS1 and BS2. Zn2+, Cu2+ and Ni+ all had obvious inhibitory effects on these five oligo-1,6-glucosidases. When p-nitrobenzene-α-D-glucoside was used as the substrate, the conversion number and catalytic efficiency of these enzymes from high to low were KP> BC1> BS1> BS2> BC2. The substrate utilization characteristics of five oligo-1,6-glucosidases were studied by using maltose, isomaltose, sucrose, lactose, trehalose and soluble amylose considering the components of residual sugar in lactic acid fermentation broth. The most suitable substrate for BC1, BC2, KP and BS1 was isomaltose, and the most suitable substrate for BS2 was maltose. [Abstract](538) [FullText HTML](237) [PDF 1778KB](4) Abstract: Taking bump-type gas foil thrust bearing as the research object, a force and deformation model of bump foil and top foil were established by elastic mechanics analysis. The foil structure deformation was calculated and the gas film thickness equation was obtained. On this basis, a fluid-solid coupling model used for calculating the lubrication performance of bump-type gas foil thrust bearings was established with use of Reynolds equation for compressible gas. The established fluid-solid coupling calculation model was verified with specific literature, proving the reliability of the algorithm. With a specific example, the dimensionless gas film pressure distribution, dimensionless gas film thickness distribution and foil structure deformation distribution of the bearing were calculated numerically. The lubrication performance of foil thrust bearing and that of rigid thrust bearing were compared. It was found that the gas film thickness of foil bearing was bigger, while the bearing capacity and friction torque of it were smaller. The influences of bump foil thickness tB, half bump length l, bump radius R0 and top foil thickness tT on the lubrication performance of the bearing were studied, and relevant curves were obtained, which showed that bearing capacity and friction torque will increase as tB or tT increase, and decrease as l or R0 increase. [Abstract](377) [FullText HTML](260) [PDF 832KB](2) Abstract: The sign language recognition technology based on computer vision brings great convenience to bilingual teaching in deaf schools. One of the difficulties of sign language recognition technology is the extraction of video key frames. According to the characteristics of sign language video keyframes and sign language habits of sign language users, this paper proposes a video key frame extraction and optimization algorithm for sign language recognition. Firstly, the convolutional auto-encoder is used to extract the deep features of video frames, and then, K-means clustering is performed. In each kind of video frames, the clearest video frames are selected as the keyframes for the first time. Then, the point density method is used to optimize the first extracted key frames, and the final extracted key frames are obtained for sign language recognition. Finally, it is shown via experimental results that the proposed algorithm can reduce substantial redundant frames and improve the accuracy and efficiency of sign language recognition. [Abstract](322) [FullText HTML](225) [PDF 803KB](3) Abstract: In order to improve the accuracy of personalized film and television recommendation, a hybrid recommendation algorithm CAMF-CM is proposed, which combines a decision tree model and a matrix decomposition algorithm containing user context information. A matrix decomposition algorithm that incorporates context preferences is used to obtain the initial movie recommendation list TOP-N. Then, a decision tree algorithm is used to perform feature label training on the context data set Ldos-Comoda to obtain the user's movie preferences in a given context. According to the TOP-N recommendation results obtained previously, the user's selection tendency in a given context is collected by the decision tree model, and the TOP-N list is filtered again to obtain the final TOP-N recommendation list. The method of verifying the efficiency of the algorithm is a ten-fold cross-validation method, which calculates the MAE mean of the collaborative filtering algorithm, the basic matrix decomposition algorithm, the Baseline prediction algorithm, and the CAMF-CM hybrid algorithm. The final result is obtained by comparing the size of the MAE mean. This method can solve the problem of the lack of interpretability of the results obtained by the traditional matrix factorization algorithm, and it can also solve the problem that the traditional recommendation algorithm does not consider the situation. After a comparative selection of decision tree models in the context data set LDOS-CoMoDa, compared with user-based collaborative filtering algorithms, basic matrix decomposition algorithms, and Baseline recommendation algorithms, the CAMF-CM recommendation algorithm has higher accuracy. [Abstract](59) [FullText HTML](32) [PDF 1553KB](0) Abstract: With the increase in the number of electric vehicles connected to the grid and the continuous increase in battery capacity, the uncoordinated charging has been bringing tremendous pressure to the grid, and even affect the stability of the operation of the grid. On the contrary, reasonable dispatch of electric vehicles can bring additional benefits to the grid. This paper proposes a sliding window variable speed optimization charging method to achieve the real-time V2G scheduling of grid-connected electric vehicles. The real-time electricity prices are combined to minimize economic costs, the network loss is quickly solved through offline network loss sensitivity, and then, the battery aging cost is quantified via charging power fluctuation method. By constructing a multi-objective optimization problem composed of battery aging cost, charging cost, and grid loss cost minimization, the V2G real-time scheduling strategy is obtained via a convex optimization algorithm. Finally, the comparative experiments are made about the average distribution scheme, natural charging scheme, and the proposed sliding window variable speed optimized charging scheme on the improved IEEE33 node distribution network, from which it is shown that the proposed scheme can slow down battery aging and effectively reduce charging costs and network losses, and balance the loads. [Abstract](62) [FullText HTML](39) [PDF 887KB](2) Abstract: This paper analyzes the heat transfer process of the burner rim during the process of non-catalytic partial oxidation of gas hydrocarbon by means of numerical simulation. The influence of the nozzle channel configuration on the combustion process in the partial oxidation reformer and the heat transfer process of burner rim is investigated. The results show that the three channel burner, which makes the inner channel flow oxygen, the middle channel flow carbon dioxide and the outer channel flow gas hydrocarbon, can increase the distance between the high temperature region and burner rim, so the three channel burner can reduce the heat transfer amount of the burner rim. As a result, the three channel burner makes the temperature of the outer rim surface lower; The two channel burner uses carbon dioxide to dilute oxygen by means of making the inner channel flow both carbon dioxide and oxygen. The method of diluting oxygen by carbon dioxide in the partial oxidation burner could reduce the intensity of the combustion, which makes the combustion temperature in the furnace lower, especially near the burner rim. The lower combustion temperature can reduces the amount of radiation heat transfer in the two channel burner rim. So the temperature of each burner rim in the two channel burner is lower than the temperature in the three channel burner. Meanwhile, the two channel burner can also improve the thermal stress distribution of the burner rim. So the two channel burner has more advantages in burner rim temperature and thermal stress distribution than the three channel burner. [Abstract](556) [FullText HTML](289) [PDF 1156KB](3) Abstract: With the sewage treatment process becoming more and more complex, the proportion of easy-to-measure and hard-to-measure variables is seriously out of balance such that the traditional supervised soft-sensor modeling cannot meet the actual requirements. Aiming at this problem, this paper proposes a new soft-sensor model, semi-supervised tri-training MPLS. The labeled data are divided into three independent parts, from which the unlabeled data with high confidence will be selected to improve the prediction ability of the model. In addition, the single-output model is upgraded to the multi-output model to directly predict multiple output variables. Finally, it is shown from the simulation results via the BSM1 platform (Benchmark Simulation Model-1) that the proposed soft-sensor model has good prediction ability on multiple output prediction and satisfactory prediction on single target. [Abstract](787) [FullText HTML](404) [PDF 1041KB](4) Abstract: In this study, continuous and single crystal graphene films on copper (Cu) are synthesized by low pressure chemical vapor deposition (LPCVD) in the growth time of 40 minutes with the meticulously modulation of the oxygen and carbon supply in multistages synthesis processing and graphene properties dependence on the oxygen and carbon supply has been investigated. Optical microscope, field emission scanning electron microscope (FESEM) and atomic force microscope (AFM) are employed for morphology characterization while the graphene films structure are measured by transmission electron microscope (TEM), selected area electron diffraction (SAED) and Raman spectrum. It is found that double oxygen passivation (with the oxygen passivation in both nucleation and growth stages) together with the optimal methane (CH4) : hydrogen (H2) ratio will lead to the balance between nucleation and graphene growth rate to accomplish continuous single crystal bilayer graphene films in short time. The remarkable properties difference between the graphene processed by single and double oxygen passivation as well as the strong properties dependence on ratio of CH4:H2 with double oxygen passivation indicate that the nucleation and growth of graphene domains can be properly modulated by the oxygen passivation and carbon supply. Moreover, the graphene-based field effect transistor (FET) reveals the superior hole mobility of 4347 cm2/(V·s). Our study provides a simple LPCVD procedure to achieve high quality graphene film on Cu in short time. [Abstract](671) [FullText HTML](347) [PDF 838KB](0) Abstract: A drug delivery system was designed in this paper. The system was composed of (6,5) chiral single-walled carbon nanotube ((6,5)SWCNT), doxorubicin hydrochloride (Dox), human serum albumin (HSA), and folic acid (FA). Firstly, the Dox-HSA-FA was prepared. (6,5) SWCNT was isolated by aqueous two-phase extraction. Then (6,5) SWCNT-Dox-HSA-FA was dispersed into Dox-HSA-FA by ultrasonication. Finally, cytotoxicity evaluation of the complex was performed using Hep G2 cells. The results showed that the IC50 of Dox-HSA-FA and (6,5) SWCNT-Dox-HSA-FA were 27.3 and 25.7 μg/mL, respectively. The results indicated that the targeting effect of Dox was enhanced in the (6,5) SWCNT-Dox-HSA-FA complex. [Abstract](75) [FullText HTML](49) [PDF 1054KB](0) Abstract: Nowadays, with the increasing data dimension of detection and storage in industrial process, the traditional detection methods have some problems such as slow processing speed and difficult feature extraction. Therefore, the research on fault detection technology based on high-dimensional data is very necessary. In this paper, a fault detection method based on adaptive sparse representation and locality preserving projects(ASRLPP) is proposed. Firstly, the sparse dictionary learning algorithm is used to construct the residual space for feature extraction, which makes the global feature of the data more obvious. Then, the locality preserving projections (LPP) algorithm is used to reduce the dimension of the data in the residual space. LPP can effectively preserve the local features of data. Finally, T2 statistics is used to calculate the control limit for monitoring. In the process of monitoring, the adaptive updating rules are introduced to update the initial training data. It can improve the efficiency and accuracy of fault detection by dynamically updating the control limits. Through numerical example test and Tennessee-Eastman(TE) process simulation, it is proved that ASRLPP is superior to LPP and Sparse Residual Distance(SRD), ASRLPP has better fault detection ability, numerical examples and TE process simulation results verify the effectiveness and superiority of the proposed algorithm in fault detection of industrial process. [Abstract](71) [FullText HTML](51) [PDF 1055KB](1) Abstract: A series of amphiphilic block copolymers C10-AZO-C10-PDPAn-PEG45 (C10-azobenzene-C10-poly[2-(diisopropylamino) ethyl methacrylate]- polyethylene glycol) (n=30,50,80) had been designed to improve stimuli-responsibility of pH/ photo dual-responsive drug delivery system. In this paper, we used three steps to synthesize copolymers. The data of proton nuclear magnetic resonance spectroscopy (1H NMR) and gel permeation chromatography (GPC) showed that copolymers were accurately synthesized. The florescence intensity ratio (I372/I383) of copolymeric micelles determined that the CMC (critical micelles concentrations) was negative correlation with PDPA polymerization degree. The image of Transmission electron microscope (bar=100 nm) showed the copolymers were self-assembled to obtain uniform stable spherical micelle with particle size of 140-200 nm (0.3 mg/mL). Dynamic light scattering measurements were used to assess the diameters and zeta potentials of self-assembled copolymer micelles. Results showed that the copolymeric micelles were fine dispersed in water environment. The structure of micelles was sensitively correlation with pH change. Their pH-triggering points of copolymers were in the range of 6.3-7.2. And then, the reversible photo responsibility had been investigated via UV-visible spectrophotometer. It was found that the absorption value of each copolymer micelle‘s solution decreased in 350 nm (characteristic absorption peak of trans-AZO) and increased slightly in 440 nm (characteristic absorption peak of cis-AZO) when they were irradiated with 365 nm ultraviolet light. The result indicated that the trans structure alter to cis structure. After the solutions were irradiated with visible light of 470 nm, the cis structures were found to alter to trans structures again. Herein, we choose C10-AZO-C10-PDPA30-PEG45, whose pH-triggering points fitted the pH environment of normal and cancer cells, to use in further experiment. In vitro release kinetics of copolymer micelles were studied using fluorescence spectrophotometer under different conditions. The cumulative drug release amount in pH=7.4 was apparently lower than pH=6.4 and 5.0. And it was found that the release amount of micelles irradiated by Ultraviolet rays were higher than no-irradiated sample. These results exhibited that the environmental stimuli responsibility of the copolymer micelles could control drug release through pH and light stimulation. Finally, we transfected the blank micelles to Hela cell, the CCK8(Cell Counting Kit-8) experiments indicated that micelles had low cytotoxicity. Therefore, this copolymer-based drug carrier could be expected to achieve controllable drug release in response to different conditions. [Abstract](81) [FullText HTML](61) [PDF 955KB](0) Abstract: Recombinant Bowman-Birk soybean trypsin inhibitor (rBBTI) was successfully expressed with E. coli (BL21) expression system, and purified and separated by Ni and DEAE-FF column affinity chromatography. The enzymatic properties of natural BBTI and rBBTI were studied, it was showed that they were stable at high temperature, but inhibitory activity were greatly influenced by pH. The results also indicated that optimal pH and temperature of inhibiting trypsin were 8.0, 25 ℃, respectively, however the optimal pH for inhibiting chymotrypsin was 9.0 and the optimal temperature was 16 ℃. The inhibitory mechanism of BBTI and rBBTI suggested that they were anti-competitive inhibitor interacted with trypsin, and were noncompetitive inhibitor against chymotrypsin. Meanwhile, they were more efficiently when inhibiting trypsin. The inhibition efficiency of BBTI was slightly higher than rBBTI. [Abstract](71) [FullText HTML](54) [PDF 1347KB](0) Abstract: α-Al2O3 is widely used in the fields of machinery, chemical industry, electronics and other fields due to its excellent properties such as high hardness, ultra-high wear resistance, and chemical resistance. At present, most of the methods for preparing α-Al2O3 powders use different precursors calcinated at certain temperature. Many researchers have done a lot of research on the phase transition of alumina. However, there are few comparative studies on the phase transition process of different precursor materials. In this study, α-Al2O3 was synthesized by using γ-AlOOH and γ-Al2O3 as precursor materials and MgO as a doped additive. The phase transition process was characterized by means of SEM, XRD and particle size distribution. The results show that both γ-Al2O3 and γ-AlOOH undergo α phase transition process of γ-Al2O3→ θ-Al2O3→α-Al2O3 during calcinations and pure α-Al2O3 phases could be obtained at 1200°C and 1100°C respectively. The temperature for pure α-Al2O3 phase is affected by the particle size distribution of γ-Al2O3 formed during its calcination. And MgO doping additive can promote the α-Al2O3 phase transition process. The promotion effect is most obvious when the doping amount is appropriate and it would be weakened when the doping amount is too high or too low. When the MgO doping amount is 0.5wt%, the temperature at which γ-Al2O3 completes the α phase transformation is 1050°C, which is 150°C lower than that in the case without MgO. When γ-AlOOH is 0.3wt% and 0.5wt% of MgO doped, the temperature for complete transition to α-Al2O3 is 1075°C, which is 25°C lower than the case without MgO. The promotion effect of MgO on the phase transition of different precursors is affected by the size of the primary particles of the powder. [Abstract](67) [FullText HTML](56) [PDF 1337KB](1) Abstract: Spray cooling is a technology of increasing interest for the high heat flux application, and is characterized by high heat transfer, rapid cooling, and less cooling water consumption. In this work, a numerical study was carried out on the process of cooling water spray shock chilled syngas in the pipeline. To determine the influence of different initial conditions on velocity field and temperature field in the pipeline, numerical studies were performed by varying the nozzle diameter, nozzle spray half angle, and the cooling water mass flow rate. Based on the Euler method, the gas phase flow field in the pipeline was calculated by using Realizable k-ε turbulence model. Based on the Lagrange method, the droplet trajectory was calculated by using the stochastic trajectory model. And the interphase mass and heat transfer between the gas phase and the droplet was solved by the bidirectional coupling method. Simulation results show that reducing the nozzle diameter, increasing the nozzle spray half angle, and increasing the cooling water flow can reduce the syngas temperature. By using a pressure swirling atomizing nozzle with the diameter of mm and the spray half angle of 70°, the syngas(7472.99 m3·h−1) temperature can be reduced from 1523.31 K to 1273.15 K when the cooling water flow rate is 1.41 kg·s−1. Effective cooling of the syngas before the fire tube waste heat boiler is achievable and can be used for the optimization of the operation environment of waste boiler. [Abstract](625) [FullText HTML](278) [PDF 997KB](1) Abstract: Nano-silica is widely used in industrial fields such as rubber, coatings and adhesives. Dispersion is an important indicator affecting its application performances. The oil absorption value can be used to characterize the branched structure of the nanoparticles and can also be used as an indicator to characterize the dispersion of the nanoparticles. A new method for dealing with precipitated nano-silica particles by high-temperature rapid flame was proposed. The influences of flame parameters on the oil absorption value of nano-silica particles were investigated by designing an orthogonal experimental system, and the adsorption of water on the surface of nanoparticles was studied as well. The variation of the adsorption water content on the surface of the nanoparticles and the number of surface hydroxyl groups were studied, and the optimized treatment conditions had been obtained. Then we added the processed samples into the silicone rubber, which successfully improved the mechanical properties of the silicone rubber. The results showed that high temperature fast flame can greatly reduce the adsorption water content and surface hydroxyl number of the nanoparticles. Under the optimized flame treatment process, the adsorbed water content of nanoparticles decreased by 28.3% and the number of surface hydroxyl groups decreased by 27%, compared with untreated samples. At the same time, the dispersion, reinforcing properties and vulcanization properties of nanoparticles in silicone rubber were studied. The treated samples were used as silicone rubber reinforcing fillers. Compared with untreated samples, the tensile strength of the treated sample was increased by 41.6%, and the tear strength was increased by 100%. [Abstract](377) [FullText HTML](206) [PDF 679KB](2) Abstract: Study on the preparation of fulvic acid and humic acid from nitric acid-oxidized rice straw by through single factor analysis and orthogonal experiment, the effects of concentration of nitric acid, temperature, time and liquid-solid ratio on the yield of fulvic acid and humic acid were investigated, and optimal process conditions for fulcic acid were obtained. The result of single analysis shows that increase the concentration of HNO3 within a certain range, increase reaction temperature and increase reaction time can increase the yield of fulvic acid, the effect of liquid-solid ratio on the yield of FA and HA was not significant. The same conclusion was obtained by the range analysis of the FA yield in the orthogonal experiment. The optimal conditions obtained by the orthogonal experiment are: HNO3 concentration 5%(quality score), reaction temperature 90 ℃, liquid-solid ratio 13/1(mL/g), the average yield of fulvic acid of the reaction for 1 h was 32.63%, the yield of humic acid was 12.77% under this condition. Elemental analysis shows that C/O of the FA and HA is 0.87 and 1.93, the C/H of the FA and HA is 0.78 and 0.73, which indicated the high biological activity and obvious aroma characteristics of the product. Infrared spectroscopy showed that FA contains obvious aromatic characteristics, acidic groups and nitro groups which proved the oxidation and nitrification of HNO3, the nitro group of HA is not obvious. The UV-visible spectrum analysis showed that the E4/E6 of the FA was 13.87 and the HA was 8.47, both are higher than FA and HA prepared from low rank coal which further expressed its higher activity. 牛永健, 杨澜, 朱诗杰, [Abstract](317) [FullText HTML](206) [PDF 931KB](2) Abstract: The contact angles of five types of fine ash with different particle size distributions from opposed multi-burner coal water slurry gasification were measured by Washburn riser, and the reference solution for measuring the effective radius is n-hexane. X-ray diffraction and fourier infrared spectrometer were used to determine the XRD pattern and infrared spectrum of the fine ash. The surface groups, crystal mass fraction and crystallinity of inorganic minerals were analyzed in order to find out the influence of physical and chemical properties on its wettability. The results show that the contact angle of the opposed multi-burner coal water slurry gasification fine ash decreases as the particle size increases, but it does not change monotonously with the particle size. In addition to the particle size, the contact angle is still affected by other physical and chemical properties. Surface groups mainly composed of Si−O−Si and −OH and inorganic minerals mainly composed of SiO2 are the main physical and chemical properties that affect the wetting characteristics of particles in addition to particle size. All three factors contribute to the enhancement of particle wettability. There is a good linear relationship between the peak areas of the surface groups of Si−O−Si and −OH in the infrared spectrum and the contact angle of fine coal gasification ash. As the peak area of the group increases, the wetting contact angle decreases. It indicates thatt the surface group peak area represented by Si−O−Si and −OH can be used as a quantitative index to characterize the wettability of the same coal gasification fine ash. [Abstract](269) [FullText HTML](196) [PDF 1069KB](1) Abstract: Cardiomyopathy is a common disease and an important cause of premature death. The development of a gene therapy vector for cardiomyopathy is the key to gene therapy of cardiomyopathy. In order to build a gene therapy vector targeting myocardium. In this study, the 8 selected AAV (AAV1-4, AAV6-9) capsid genes were recombined by DNA shuffling technology, and a random mutant AAV capsid library was constructed, and the random mutant AAV capsid library was constructed in mice Direct screening, and finally screened to obtain new AAV capsids with high myocardial targeting and low liver targeting, AAVH50 and AAVH59. Through the tail vein injection, the luciferase (Luciferase, Luc) gene carried by them was delivered to mice, and it was found that among the 11 tissues tested, the gene expression of AAVH50 and AAVH59 in myocardial tissue was higher than other tissues. Compared with AAV6 and AAV9, AAVH50 and AAVH59 expressed similar levels of luciferase in the myocardium, and the expression in the liver significantly decreased AAV9. After AAVH50 and AAVH59 infected primary neonatal rat cardiomyocytes, it was found that the efficiency of the selected AAVH59 in direct myocardial infection was significantly higher than that of AAV9. Therefore, this study screened to obtain a new type of AAV vector with high targeting to myocardium, and to the liver and low targeting, which is expected to provide a new type of AAV vector for gene therapy of myocardial diseases. [Abstract](369) [FullText HTML](263) [PDF 1233KB](1) Abstract: The effects of bubbles in the liquid jet on the air-blast atomization of viscous liquid were investigated using the Malvern laser particle size analyzer. The glycerol-water solution (Oh=3.46×10-2~0.407) is used as the liquid phase, and air as the gas phase. Experiments with various coaxial gas velocities (ug=94.8~142 m/s) and liquid jet velocities (ul,0=0.29~1.21 m/s) were conducted to study influences of inner bubbles on the droplets size. It was found that at low Oh, the droplet size decreases with the volumetric flow rate of aerating gas for the low liquid jet velocity, and the droplet size increase with the volumetric flow rate of aerating gas for the high liquid jet velocity; the droplet size increases with the volumetric flow rate of aerating gas at high Oh. A model is deduced to delineate the variation trend of the droplet size. We compared the predictions of this model with experimental results and found the relative deviations are less than ±5%. [Abstract](292) [FullText HTML](247) [PDF 1052KB](2) Abstract: A galactose-conjugated perylenediimide was loaded onto 2D MoS2 platform through π-π stacking, Moreover, encapsulating the antibiotic ceftazidime to form a P. aeruginosa-targeted therapeutic system. Perylenediimide as photosensitizer could produce reactive oxygen species upon light irradiation for photodynamic therapy, which further realizes combined chemo- and photodynamic therapy towards P. aeruginosa. This complexed system hugely reduces the dose of antibiotics, diminishes drug-resisting effects and provides new therapeutic insights for clinical-chronic bacteria. [Abstract](347) [FullText HTML](306) [PDF 1014KB](2) Abstract: The gasification characteristics of petroleum coke, fine slag and Shenfu coal char were comparatively studied using a high temperature stage microscope (HTSM) system. Petroleum coke mixed with Shenfu slag were prepared for comparison. The thermogravimetric analyzer (TGA) was used to compare the gasification reactivities of the different samples. It was found that the gasification reactivity of fine slag was obviously better than that of petroleum coke and slightly worse than that of Shenfu coal char at 1200 ℃. The addition of Shenfu slag accelerated the reaction rate of petroleum coke, indicating that the ash contained in the fine slag promoted the gasification reaction. The images of micro structure of petroleum coke and fine slag sample obtained from a scanning electron microscope showed that the surface of petroleum coke was very dense with few pores that can be clearly observed. The structure of fine slag particles was relatively loose. Micron-sized pores could be observed. The results of specific surface area and pore structure analysis showed that compared with petroleum coke, the pore structure of fine slag was developed after the gasification process that the specific surface area of which was about 15 times than petroleum coke. There were more 2-10 nm pores in the fine slag sample. The irregular pore structure of fine slag provided more surface for the gasification reaction and accelerated the gasification reaction rate. In addition, according to the results of the micro-Raman analysis, fine slag was relatively low in graphitization tendency compared with petroleum coke, which reflected the good gasification reactivity of fine slag. [Abstract](287) [FullText HTML](234) [PDF 882KB](1) Abstract: Glucose oxidase (Glucose oxidase, GOD) is widely used in food, chemistry, medicine, biotechnology and other industrial applications. In this study, the GOD gene from Aspergillus niger was optimized according to the codon bias of P. pastoris, then used to construct the GOD secretory expression vector pPIC9K-GOD and the corresponding recombinant P. pastoris strain G/GOD. Subsequently, the higher concentration of geneticin (G418) was used to select the multicopy genomic integration strain G/GODM, and the extracellular GOD specific activity was improved to 5843.2 U/g·DCW, which was 8.2-fold that of the single copy strain G/GOD. On the basis of this first generation high producing strain, additional co-expression of folding factors, as well as the enhancement of central carbon metabolism, was tried to construct the second generation strain. Co-expression of the protein folding factors PDI1, PDI2 and HAC1 improved the extracellular GOD activity by 32.7%, 8.9% and 54.4%, respectively. With the co-expression of the pentose phosphate pathway gene SOL3 and the tricarboxylic acid cycle gene MDH1, the extracellular GOD activity was enhanced by 6.3% and 11.6%, respectively. The best strain G/GMH1 was selected for the bioreactor fermentation to achieve 6656.6 U/g·DCW of the extracellular GOD activity in a 50-L bioreactor, indicating its value for industrial application. [Abstract](297) [FullText HTML](227) [PDF 998KB](0) Abstract: Based on the 12-lumped kinetic model established in the laboratory for residue fluid catalytic cracking (RFCC), an industrial reactor model for RFCC was established by setting unit factors and recycle calculation. An industrial simulation software of the model for unit factors calculation and product distribution prediction was developed. Based on the kinetic parameters from the laboratory model and steady operation data from an industrial unit, the unit factors were calculated by combining the fourth order Runge-Kutta method and the BFGS optimization algorithm. It is proved that the relative errors between the predicted yields and the actual yields of the products are mostly within 5%, which indicates the reliability of the industrial reactor model established for RFCC and the unit factors. The effect of reaction temperature and catalyst to oil ratio on product yields was also investigated. The prediction of product distribution trend by the software is consistent with catalytic cracking reaction rules, indicating that the reliability and extrapolation of the model are good and laying a good foundation for the further industrial application of the model. [Abstract](433) [FullText HTML](236) [PDF 856KB](1) Abstract: Pd/C catalyst was applied to the reaction of hydrogenation of phenol to cyclohexanone. After comparing the dichloromethane, cyclohexane, ethanol, and benzene, benzene was selected as the solvent. The effects of reaction conditions such as temperature, pressure, molar ratio of hydrogen to phenol, and phenol mass space velocity on the hydrogenation of phenol were investigated by controlling variables. A fixed bed tubular reactor was charged with 80-100 mesh Pd/C catalyst. 25 groups of experimental data were measured by changing the temperature, pressure and molar ratio of hydrogen to phenol. A intrinsic kinetic model was established on the ideal adsorption model and the parameters were estimated using 25 sets of orthogonal experimental data, and the dynamics model was tested. The results show that the suitable reaction conditions are: reaction temperature 175 ~ 205 ℃, reaction pressure 0.1 MPa, n(H2)/n(phenol) 4, and the weight hourly space velocity of phenol 0.2 ~ 0.4 h-1. After inspection, the established intrinsic kinetic model has good reliability. [Abstract](294) [FullText HTML](235) [PDF 663KB](2) Abstract: The emulsified asphalt products have many disadvantages used as shale inhibitors for drilling fluid, such as high colloid content, poor stability, serious pollution, poor dispersion and poor anti-collapse. In this work, a C9 petroleum resin and an aromatic oil are used as the main blending raw materials. The preparation procedure is similar to the conventional preparation method of asphaltic-type shale stabilizer. After the sequential steps of blending, emulsification, and stabilization, a new type petroleum resin shale inhibitor (PRSI) was obtained. Results showed that the PRSI could inhibit shale swelling, dispersion, and reduce the filtration loss. In addition, PRSI has good compatibility with other additives and does not affect the rheological properties of drilling fluid. When the dosage is 2wt.%, it reduces the water loss of drilling fluid by 18wt.%, and the relative reduction rate of core expansion is 8% higher than that of the emulsified asphalt. As a shale stabilizer, it has a good application prospect in oil and gas drilling. [Abstract](322) [FullText HTML](237) [PDF 919KB](1) Abstract: Coenzyme Q10 is an important hydrogen transmitter in respiratory chain, which plays an important role in human body. It has been widely used in the treatment of cardiovascular and cerebrovascular diseases, and has been applied in cosmetics, health care products and other aspects. With the development of research, the market demand and industrial output of coenzyme Q10 are constantly expanding. Microbial fermentation is the most promising method for the production of coenzyme Q10. This study used atmospheric and room temperature plasma (ARTP) towards Rhodobacter sphaeroides to obtain mutants. Meanwhile, an oxygen-limited model was established to screen the strains which could suffer the low oxygen concentration. The bacterial suspension was treated by ARTP for 25 s, then cultured on the plate with 0.4 g/L sodium sulfite. The strains were fermented in 2 mL volume for 48 h. In the primary screening 24-well plates, 6 mutants were obtained. Furthermore, these mutants were cultured in shake flask to verify genetic stability. A mutant R. sphaeroides F5D13 performed good stability and production of Coenzyme Q10.The titer of R. sphaeroides F5D13 was improved from 86.2 mg/L to 111.8 mg/L compared to the original strain. Finally, the yield of Coenzyme Q10 reached 770.1 mg/L in 5 L fermentation after 100 h, which was increased by18.0%. According to the fermentation parameters, the mutant R. sphaeroides F5D13 showed the advantage of biomass in the cell growth phase and strong oxygen demand in product synthesis phase, which leaded to the higher oxygen uptake rate and yield than the original parent strain. [Abstract](281) [FullText HTML](249) [PDF 900KB](1) Abstract: A hydrophobic coating was prepared via a simple NaCl-dissolution-assisted etching silicon template method. And epoxy resins, with excellent properties, were selected as the matrix. The effect of sodium chloride concentration and spraying times on the microstructure and wetting properties of the coatings were studied. The results show that a multi-stepped rough structure formed gradually with the increase of salt concentration and the spray times. After using saturated salt solution spraying 30 times, the water contact angle (WCA) of the surface increases from 80.2° to 130.0°, indicating its good hydrophobicity. Besides, the coating shows superior abrasion resistance and chemical stability for strong acid and alkali solutions. Even after 50 times of abrasion test, the hydrophobicity of the surface hardly changed. Furthermore, the morphology of the prepared porous silicone template retains well after 20 casting and demoulding cycles, indicating its excellent reusable performance. [Abstract](376) [FullText HTML](241) [PDF 947KB](5) Abstract: Porous carbon derived from wasted cigarette filters (WCFs) were synthesized using an atmospheric-pressure chemical vapor deposition, using KOH as activator at 500-700 ℃. Brunauer-Emmol/Lett-Teller test showed that the surface area of porous carbon derived from WCFs increased with activation temperature. Micro- and meso-porous carbon (MMOL/LC) derived from WCFs at 700 ℃ (MMOL/LC700) exhibited a micro-pore dominant structure (pore size <2 nm), with a surface area of 928 m2/g. MMOL/LC700 powder was made into electrodes for capacitive deionization and, with an initial NaCl concentration of 5 mmol/L, the MMOL/LC700 electrode showed an ion adsorption capacity of 8.66 mg/g upon a bias of 1.2 V. MMOL/LC700 showed a carbon yield of 4.9% from its original WCFs. XPS showed that MMOL/LC700 contains a carbon content of 92.87%. 700 ℃ is a relative low activation temperature which provides a low vapor pression of KOH, benefiting the environment. This work suggests a facile method of converting WCFs into porous carbon, and its application in water desalination based on capacitive deionization. [Abstract](372) [FullText HTML](259) [PDF 1186KB](4) Abstract: With the advent of depth camera such as Microsoft Kinect, the method of recognizing human action using 3D skeleton node data with it’s simplicity, robustness and view-independent representation has achieved quite good performance. But the representations of skeleton sequences learned by most of the existing methods lack spatial structure information and detailed temporal dynamics features. Therefore, the BI-LSTM model the characteristics of long-term storage of skeleton sequences is used in this paper to obtain rich bidirectional time information and model the sequence of actions. And at the same time, the relative distance features and angle features between joint points extract from 3D bone joint point coordinates to strengthen the spatial structure features and complete the recognition of human action from the skeletal data. The results show that this method effectively classifies human actions and improves accuracy. [Abstract](343) [FullText HTML](271) [PDF 696KB](0) Abstract: Nanopore is a highly sensitive single-molecule detection technology, which researches the information of single molecule by capturing the ion current signal generated when the molecule traverses the nanopore. However, because the different capture rates of different molecules in the nanopore, the dataset collected is unbalanced, which affects the accuracy of the identification of molecules. Therefore, a Generative Adversarial Networks(GAN) is introduced in this paper. Based on the blockage events of the encoded DNA molecules, a model based on the Deep Convolutional Generative Adversarial Networks (DCGAN) is constructed to augment the minority samples to achieve the balanced processing of dataset. In addition, QuipuNet is used to identify the dataset before and after the balancing. The results show that the average classification accuracy of dataset augment by our method is 0.96, which is better than the original dataset of 0.92 and others. What’s more, the identification accuracy of barcode ‘100’ is increased from 0.82 to 0.96. This method extends the feasibility of encoded DNA molecules to balance the dataset and improve the identification accuracy. [Abstract](336) [FullText HTML](255) [PDF 926KB](1) Abstract: The performance of semantic segmentation systems using visible cameras usually reduces dramatically at night or in bad weather conditions, due to its susceptibility to the variable lights. Simultaneously using visible cameras and thermal IR sensors can alleviate this problem. Although there is some work that studied the semantic segmentation of RGB-IR images, few works attempted to improve the segmentation results by enhancing the discriminability of the fusion feature. Therefore, we propose a novel framework of multi-spectral image semantic segmentation based on the process of supervised feature fusion. Firstly, the independent feature fusion modules constitute a whole fusion branch in the semantic segmentation network, so that the fusion of high-level features can guide the fusion of lower-level features. Then, the segmentation supervision signal is directly applied to the end of the fusion branch to improve the discriminability of the fusion feature and the convergence speed of the network. Finally, a dice loss instead of the cycle loss is used as the supervision of fusion branch to improve the segmentation of small objects, which along with the cycle loss on segmentation branch leads to a hybrid supervision. The experimental results on two multi-spectral datasets show that, compared with other multi-spectral semantic segmentation methods, the proposed method can achieve better segmentation results and is more advantageous for small objects segmentation. [Abstract](317) [FullText HTML](214) [PDF 782KB](1) Abstract: Aiming at the tracking failure caused by camera jitter or low-texture environment in slam, and for the task of 3D map reconstruction, a hybrid slam method R-ORB slam for depth camera is proposed in this paper. A pose estimation method based on photometric error is used as the prior of the feature-basedodometer, and the result of the method is used to participate in pose estimation in the case of ORB-SLAM2 tracking fail. At the same time, for generating dense three-dimensional point map with non-redundant points, a filter is used for down sampling of the global point cloud map obtained by fusion all point clouds of each key frame. Then, by using Poisson algorithm to reconstruct the surface of 3D point cloud map, the 3D map model is generated. Experiments on two popular open datasets show that the proposed method can effectively solve the problem of tracking failure and realize 3D reconstruction with high tracking accuracy and reconstruction accuracy. [Abstract](416) [FullText HTML](390) [PDF 932KB](4) Abstract: The global optimization problem has been widely used in various fields, but the traditional method relies on the gradient information of the objective function too much. The meta heuristic search algorithms have better flexibility and it can be used to solve practical problems. Hence, a ice crystal continuous optimization algorithm based on reinforcement learning and angle penalty distance (APD-CEO), which introduces probabilistic update strategy based on reinforcement learning and deviation strategy based on angle penalty distance, is proposed for the global continuous optimization problem. Firstly, ice crystal continuous optimization algorithm is proposed to solve the continuous extremum problem by simulating the freezing process of lake water. Secondly, in order to eliminate the error in calculating the energy from the temporary center of the lake, the Angle penalty distance strategy is introduced, and the convergence and diversity are better balanced. Meanwhile, probabilistic update strategy based on reinforcement learning can better guide the position of the newly formed crystals, accelerate the freezing process of the lake, and approach the center of lake faster (the global optimum). Finally, in order to verify the validity of probabilistic update strategy and angle penalty distance strategy, the algorithm before and after joining the strategy are compared. Moreover, APD-CEO has better performance than other algorithms in most benchmark functions, and the contrast effect is more obvious in the high dimensions. And Friedman test also shows that the APD-CEO ranks better among the five algorithms. [Abstract](344) [FullText HTML](232) [PDF 689KB](7) Abstract: Cover song identification is a relevant task in music information retrieval (MIR). To improve the cover song identification performance, recently, some researchers have proposed the song identification scheme based on non-linear graph fusion and tensor product graphs (TPGs) diffusion. It reduces the influence of noise mainly by learning the geometry structure of similarity high dimensional space. However, the model has the following aspects to be improved. First, the audio features introduced in the paper, such as harmonic pitch class profile (HPCP), main melody (MLD) and beat-synchronous chroma (BSC) are all the hand-crafting ones, and it is difficult to convey the nonlinear structure of music. Second, the algorithm only considers the audio content, and ignores the importance of lyrics information in cover song identification. Third, learning the geometry structure of similarity high dimensional space enhances the performance, and increases the computation complexity. To solve these problems, we propose a cover song identification algorithm based on the audio content and the lyrics text. To extract the high-level audio features, the deep pitch class profile (DPCP) scheme is introduced to analyze the audio content. To extract the contextual semantics and the term frequency in song lyrics, the bi-directional long short-term memory (BiLSTM) architecture and TF·IDF scheme are adopted, respectively. Finally, both the audio similarity and the similarity of lyrics are fused by the similarity network fusion (SNF) algorithm to get the final similarity. To verify the effectiveness of the algorithm, the Covers2326 dataset is constructed. The experimental results show that compared with the existing algorithm, the proposed one not only improves the identification accuracy but also improves the computational speed. [Abstract](336) [FullText HTML](263) [PDF 1034KB](2) Abstract: For multi-object tracking in complex scenes, there are problems of high object identification switching rate and high object trajectory false alarm rate. This paper proposes a multi-object tracking algorithm based on pedestrian re-identification network and CNN-GRU (Convolutional Neural Networks-Gated Recurrent Unit) metric network. By constructing a deep metric model combining CNN and dual GRU network, the time characteristics of appearance and motion features of the tracking object trajectory boxes are predicted simultaneously, so that the object has more discriminative features and the ID switch rate of object is reduced. Based on the CNN-GRU network, the correct matching probability of historical object trajectory is automatically learned. Different attentions are assigned to different track trajectory boxes of the same object, so as to suppress the influence of misdetected object boxes in the object trajectory on the overall features of the object and effectively aggregate the features of the object trajectory box. The algorithm combines the similarity of detection boxes and trajectory boxes calculated by the features of pedestrian re-identification network, and the similarity CNN-GRU network output as the matching cost of data association part. The experimental evaluation results on a standard multi-object tracking dataset show the effectiveness of the proposed algorithm. [Abstract](369) [FullText HTML](272) [PDF 751KB](4) Abstract: The process of traffic signal control can be abstracted as a typical network control system. Network control systems have been extensively applied in many fields for its easy maintenance and installation. However, there are still some problems to be take care in practical analysis and design, such as network delay, packet loss, signal quantization and multi-packet transmission. Thus, the performance of the control system might decrease, which further leads to system instability. Dealing with these problems can help to promote its application. This paper presents an adaptive event-triggered model predictive control strategy to reduce communication consumption of networked control systems. The resulting framework is used for the stabilization of uncertain NCSs subject to quantization adaptive state transmission. The system state and the predictive control law are sent by wireless network only when the triggering conditions are satisfied, where the adaptive triggering mechanism has more flexible and better performance. The adaptive triggering parameter decides how often to transmit the current sample data. Under this mechanism, a robust MPC is designed to ensure the closed-loop stability of NCS with quantized effects and achieve the desired control performance, which can reduce the energy consumption and improve the network congestion. An algorithm implementation of this method is given in the paper. Finally, an example is given to illustrate the effectiveness of the proposed results. The result shows that triggering parameter can save more communication resources on the basis of event-triggered mechanism. The proposed event-triggered model predictive control method can ensure the robust stability of the system. [Abstract](359) [FullText HTML](258) [PDF 1101KB](3) Abstract: The airport perimeter intrusion alarm system is the first line of defense in the airport's flight zone. Traditional airport perimeter intrusion alarm system has high false alarm rate and inability to classify different intrusion categories under the influence of severe weather. In order to solve the problem, an auto encoder long short term memory network model was proposed. The model extracted hidden encoder feature from input signals and constructed feature vector matrix fused with timing information to reduce the complexity of the model. The results of network model performance evaluation show that the network model has a low false alarm rate as well as a high accuracy of vibration states classification. Besides, the network model has a low complexity which guarantees a good practical application prospect. , doi: 10.14133/j.cnki.1008-9357 [Abstract](352) [FullText HTML](221) [PDF 647KB](2) Abstract: The definition of single elements was first given by Erdos, though the notion itself was used earlier by operator theorist Ringrose. It is easy to show that every rank one operator is a single element of any algebra containing it. Since the single elements play a role in the representation theory of C*-algebras and Banach algebras, several authors study the property of single elements. Erdos proved that there exists a faithful representation of any C*-algebra into the (bounded) operators on a Hilbert space in such a way that single elements are carried to operators of rank one. Ringrose investigated certain kinds of nest algebras and showed that in them a nonzero element is single if and only if it is a rank one operator. Since single elements are carried to single elements under algebraic isomorphisms, Ringrose also proved that algebraic isomorphisms between certain nest algebras are spatial. The purpose of this article is to study the linear span of the single elements in the tensor algebras of directed graphs. The notion of ‘single element’ may prove to be useful in other fields. Let \begin{document}${{ G}_n}$\end{document} be the graph consisting of a single vertex \begin{document}$\{ p\} $\end{document} and n loop edges \begin{document}$\{ {e_1},{e_2}, \ldots {e_n}\} $\end{document} i.e., \begin{document}$s({e_i}) = r({e_i}) = p$\end{document}, \begin{document}$i = 1,2, \ldots n$\end{document}. We show every element of the tensor algebra \begin{document}${ T}_{{{ G}_n}}^ +$\end{document} is a single element. Moreover, every element of the free semigroupoid algebra \begin{document}${ L}_{{{ G}_n}}^{}$\end{document} is a single element. For a countable directed graph \begin{document}${ G}$\end{document}, We show the linear span of the single elements of the tensor algebra \begin{document}${ T}_{ G}^ +$\end{document} is dense in \begin{document}${ T}_{ G}^ +$\end{document}. For a finite directed graph \begin{document}${{ C}_n}$\end{document}, we show any element of \begin{document}${ T}_{{{ C}_n}}^ +$\end{document} is a linear span of \begin{document}${n^2}$\end{document} single elements of \begin{document}${ T}_{{{ C}_n}}^ +$\end{document}. [Abstract](516) [FullText HTML](266) [PDF 1166KB](0) Abstract: A strain CQ2, which can degrade the antibiotic cephalexin effectively, was separated from the sludge of domestic sewage treatment plant, and identified as Ochrobactrum sp. The strain was identified as gram-negative bacteria with a diameter of 4-6mm. Under 1000 times optical microscope, the CQ2 bacteria was rod-shaped with a size range of 0.4—0.6×1.2—2.5 microns. This strain could not efficiently degrade CX when the CX was the only organic carbon source, and could decompose CX rapidly in the presence of glucose, indicating that the bacteria removed CX through co-degradation mechanism. The effects of temperature, pH, rotating speed and inoculation amount on the growth and degradation efficiency of CQ2 were investigated by orthogonal test. The results showed that CQ2 could effectively degrade cephalexin, and the optimal cultivation conditions are 30 ℃, pH at 7.0, mixing rate of 150 rpm, and inoculation percentage of 5%. At the optimal condition, the cephalexin at initial concentration of 10 mg/L could be completely degraded within 28 h. Moreover, under the identical condition, the tested CQ2 bacteria could completely remove amoxicillin at 36 h, significantly degrade terramycin and sulfadiazine, but played a negligible role on the degradation of pefloxacin due to the inhibition on the CQ2 growth. It is possible that the chromosome of pale bacillus contains specific AmpC gene, which can produce the cephalosporin enzyme ApmC enzyme, and therefore has strong resistance to amoxicillin and cefalexin with the structure of β-lactam ring. Based on cephalexin degradation intermediates determined by LC-MS/MS, the biodegradation preliminary pathway of cephalexin by CQ2 was proposed, 2-hydroxyl-3-phenylpyrazine is the main intermediate of biodegradation after hydrolysis. [Abstract](581) [FullText HTML](244) [PDF 795KB](2) Abstract: Pattern dynamics is an important branch of nonlinear theoretical system. When Turing instability exist in the Belousov-Zhabotinsky (BZ) reaction, the system will generate Turing Pattern. Turing Pattern is a kind of stable and non-uniform spatial structure, which resulting from the Instability of the equilibrium solution of the reaction-diffusion equation caused by diffusion, and which are different from the chemical waves generated by the BZ reaction. Based on the classical Tyson model, the Turing instability analysis of BZ reaction was carried out in this paper, and the ranges of parameters of the system corresponding to the Turing Pattern were obtained. The calculated results were verified by numerical simulation, and the possible morphology of Turing Pattern in BZ reaction was also shown. In the work process, Routh-Hurwitz criterion was used to judge the stability of the equilibrium solution, and the ranges of parameters to make the equilibrium solution stable or unstable were obtained. The partial differential equation was transformed into the sum of several ordinary differential equations by Fourier expansion method. The finite difference method was used to simulate the BZ reaction, in this method the continuous region and functions were approximatively replaced by discrete region and functions. Through numerical simulation, not only the correctness of the calculated results were verified, but also the conclusion was obtained that the bigger the difference of two diffusion coefficient is, the faster the Turing pattern appears. BZ reaction is a simple reaction-diffusion system. The methods proposed and the results obtained from the study of BZ reaction provide a reference for the study of nonlinear systems including biological systems. [Abstract](613) [FullText HTML](304) [PDF 872KB](3) Abstract: Transparent superhydrophobic coatings have good potential applications in optical devices, solar panels, automobile windshields, glass building facade and so on. However, their real-world applications are still restricted by low transparency, poor durability, and complex preparation processes. Hybrid silica sol was prepared by sol-gel process using fumed silica, tetraethoxysilane (TEOS) and hexamethyl-disilazane (HDMS) as raw materials. The transparent superhydrophobic composite coatings were obtained via incorporating the hybrid silica sol and organosilicon oligomer which is synthesized with 2,3-Epoxypropoxy propyltrimethoxysilicane (KH560) and alkyl siloxane as precursors. The influence of amount of fumed silica and HDMS on the hydrophobic property of hybrid silica sol coatings was investigated, and the effect of the ratio of KH560, the kind of organosiloxanes and the amount of organosilicon oligomer on the properties of composite coatings was studied. The results show that the excellent performance of hybrid silica sol coatings could be obtained with the water contact angel (CA) of 166° and the sliding angel (SA) of less than 3° when m (fumed silica):m(TEOS)=0.075, m (HDMS):m (TEOS)=0.75. When the molar ratio of KH560 to MTES was 0.50:1, and m (organosilicon oligomer)∶m (hybrid silica) sol=0.100, the composite coating was still superhydrophobic and the water contact angle of the composite coating remained 138°even after 5 min ultrasonic treatment. The surface topography of the coatings was investigated by SEM. The SEM results directly indicated that the surface of composite coating displayed a continuous porous network, and a large amount of micro-nano composite rough structures were observed. Furthermore, the optical transmittance of the hybrid silica superhydrophobic composite coating was as high as 85.4% at 550 nm. [Abstract](535) [FullText HTML](297) [PDF 849KB](0) Abstract: In this paper the antibacterial activity of different ethanol extracts from Glycyrrhiza uralensis Fisch (G-EA) and Magnolia officinalis (M-EA) to Streptococcus mutans were tested and compared. The bacteriostatic effect, the effect on the activity of lactic dehydrogenase (LDH) and the effect on the restrain of biofilm of the two ethanol extract compound were explored as well. The antibacterial ability of the two ethanol extracts and compound were investigated through the testing of inhibition zone, minimal inhibit concentration (MIC) and fractional inhibitory concentration (FIC) and the results showed that the FIC between G-EA and M-EA for Streptococcus mutans was 0.375, which was less than 1 and possessed a synergistic effect. After the testing of MIC values of different mass ratios of G-EA and M-EA, the bacteriostatic effect was the best for the compound against Streptococcus mutans when the mixture ratio of G-EA and M-EA was 1:2, and the MIC of compound (G-M1:2) reached 0.32 g/L. According to the growth curve testing of Streptococcus mutans, the main bacteriostatic phase of G-M1:2 was its logarithmic growth phase and stationary phase and the bacteriostatic effect of G-M1:2 to Streptococcus mutans was superior to the tea polyphenol at the same concentration. The effect of G-M1:2 on lactic dehydrogenase (LDH) activity and biofilm formation in Streptococcus mutans was investigated. It turned out that G-M1:2 could effectively inhibit LDH activity and biofilm formation and the inhibition ability were enhanced with the increase in concentration. The test also indicated the minimum biofilm inhibition concentration 50% (MBIC50) of G-M1:2 was 0.08 g/L. [Abstract](638) [FullText HTML](307) [PDF 503KB](5) Abstract: New drug design is a huge project, and the failure rate is very high. If based on existing active compounds, the design of “me-too” drugs can increase the success rate. The “me-too” drug should have the same or similar spatial structure, pharmacophore, etc. as the original active compound, so as to ensure that the combination of the “me-too” drug and the enzyme is the same as the original active compound. The lead compound can provide the same or similar spatial structure as the original active compound, and a novel skeleton, but the skeleton of the lead compound does not necessarily have good physicochemical properties. Designing “me-too” drugs based on lead compounds can significantly reduce the difficulty of new drug development and improve development efficiency and success rate. How to accurately grasp the spatial structure of the lead compound, designing a novel structure, a reasonable valence bond, and a skeleton with the same or similar spatial structure as the lead compound are the key issues in designing “me-too” drugs. The author designs and writes an automated new drug skeleton design software based on the extraction of structural long chains, fragment matching and splicing: ChemCloser. The software can provide researchers with all core frameworks with reasonable structure and the same or similar spatial structure as the lead compound. Researchers may find frameworks with novel structures, good physical properties and stable chemical properties in these core frameworks. After splicing pharmacodynamic groups on these skeletons, it can produce the same or similar biological activity as the original active compound. [Abstract](594) [FullText HTML](349) [PDF 1145KB](5) Abstract: Research based on the ultra-short baseline positioning system and Doppler velocimeter and electronic compass combination of underwater robot navigation problem, put forward a kind of based on iterative unscented Kalman filtering fusion algorithm of multi-sensor underwater integrated navigation, reduce traditional unscented Kalman filter process noise covariance matrix and measurement noise covariance matrix of the influence of the filtering precision and response time. The proposed method improves the precision of underwater multi-sensor combined navigation by iterating the results of multi-sensor data fusion several times. Firstly, the data obtained by the sensors were preprocessed. Secondly, plot the motion trajectory diagram simulated by the ultra-short baseline positioning system, the motion trajectory diagram calculated by dead reckoning and the motion trajectory diagram fused by the unscented Kalman filtering algorithm were drawn respectively. Thirdly, the unscented Kalman filtering algorithm iterates the output of multi-sensor data fusion for several times, which can achieve a better fusion effect. Finally, the feasibility and effectiveness of the combined navigation algorithm under the water are verified by multi-sensor pool test and simulation analysis. The effectiveness of the iterative unscented Kalman filtering algorithm based on underwater integrated navigation system was verified by comparing the simulated ultra-short baseline positioning data, the dead reckoning data based on the electronic compass and Doppler velocimeter and the position information of the positioning data fused with the iterative unscented Kalman filtering data. [Abstract](1206) [FullText HTML](439) [PDF 5206KB](44) Abstract:$v.abstractInfoEn
[Abstract](611) [FullText HTML](345) [PDF 802KB](1)
Abstract:
The influence of temperature, H2 pressure, hydrogen donating capabilities and catalyst on the hydroliquefaction of Hongliulin coal under mild conditions was investigated in this paper. The results show that in the range of 370~390 ℃, higher reaction temperature could promote the pyrolysis reaction of coal; in the range of 390~430 ℃, higher reaction temperature could promote the secondary cracking of heavy products. With reaction temperature increasing, the reaction pressure needs to be increased to match the reaction temperature. Moreover, compared to coal liquefaction under mild condition with recycle solvent and Fe catalyst, the effect of Fe catalyst addition on liquefaction performance with methylnaphthalene is tiny, which could be result from weak hydrogen transfer ability of methylnaphthalene. Fe catalyst has a little effect on liquefaction performance with tetralin as solvent. It could be due to that tetralin is a good hydrogen donor solvent which dissociates a large amount of activated hydrogen could stabilize most of the free radicals produced from Hongliulin coal pyrolysis, and with the addition of Fe catalyst, the activated hydrogen produced from H2 is more than needed for Hongliulin coal liquefaction process. Furthermore, the addition of alkali catalyst to Fe catalyst could promote coal conversion, oil production and H2 consumption, while reducing water production. It could be ascribed to there exists a prominent synergistic effect between alkali catalyst and Fe catalyst in Hongliulin coal hydroliquefaction, and the synergistic effect could promote the hydrolyzation of oxygen-containing moieties (such as carbonyl groups and ether bonds) and the depolymerization of macromolecular structures.
[Abstract](1971) [FullText HTML](508) [PDF 750KB](4)
Abstract:
Based on the design information of a cracking gas compressor in some ethylene unit, the compressor performance prediction model is established by modifying the design data. An improved BP algorithm (LR-GA-BP) is proposed for compressor performance prediction. The simulation calculation of a four-stage compressor system in the ethylene unit is carried out, and the relative errors between the calculation values and actual values of main components in cracking gas from the fourth-stage outlet of the compressor are less than 2%, and the relative errors between the calculation values and actual values of the outlet temperature and pressure of the compressor are less than 1%. It indicates the reliability of the model. The effect factors of the higher outlet temperature at the fourth-stage of the compressor were analyzed and the corresponding cooling measures were put forward, which is of good guiding significance to slow down the coking of compression system and further optimize its operation.
[Abstract](1912) [FullText HTML](740) [PDF 1169KB](3)
Abstract:
Arm-type tensioner is widely used in the automotive engine belt system, whose spindle often break during actual working process caused by fatigue. For this reason, it is necessary to study the mechanics properties of the tensioner and try to find a method for calculating the spindle’s fatigue life. In this paper, the arm-type tensioner in automotive engine is taken as the research object, the mechanics analysis is carried out for the tensioner in working process, the mechanics model is established for calculating the forces acted on the tensioner’s spindle, and the method for calculating the bending stress of the tensioner’s spindle is established. On such basis, and by use of the fatigue theory and rain-flow counting method, a method is established to calculate the fatigue life of the tensioner’s spindle. With a specific example, the fatigue life of the tensioner’s spindle is calculated numerically and verified by comparing with the actual life of spindle. Several parameters’ influences on the mechanics performance and fatigue life of the tensioner’s spindle are studied. It is found that, the main factors affecting the fatigue life of the tensioner’s spindle are the distance between the pulley and the rotating arm (l1) and the bushing length (l2), and decreasing l1 and l2 can effectively increase the fatigue life of the spindle, while the length of the arm L and the vortex spring torsion stiffness T’ have no significant effects on the fatigue life of the tensioner’s spindle.
[Abstract](1749) [FullText HTML](744) [PDF 1498KB](13)
Abstract:
In this paper, lean coal, fat coal and gas coal were taken as the research objects to deeply study the macroscopic gas release law and microstructural changes of coking coal during low temperature oxidation. The gas release laws were obtained by heating and isothermal oxidation and the structure of coals was characterized by N2 adsorption, scanning electron microscopy equipped with energy dispersive X-ray analysis (SEM-EDS) and infrared spectroscopy (FTIR). The results of constant temperature experiment showed that a small amount of the CO generated at a certain temperature came from the thermal decomposition of coal itself, and most of it came from the decomposition of carbon-oxygen complexes produced by oxidation reaction. N2 adsorption and SEM characterization results indicated that at 95 ℃, the destructive effect on coal structure was small, but at 190 ℃, the cracks on coal surface increased and the degree of pulverization became larger. The total volume and average pore diameter increased, but BET surface area decreased due to the blockage of some oxidation products. Al and Si elements were detected on the surface of coal, so it could be inferred that the attached particles contained Al2O3 and SiO2. FTIR characterization result showed that during the low temperature oxidation process, -OH, -CH3 and -CH2- reacted with oxygen and formed unstable carbon-oxygen complexes like C=O, -COOH and ether bonds, which were further decomposed into CO, CO2 and other gases. The thermodynamic feasibility of the proposed gas generation mechanism was verified by HSC Chemistry 6.0. Besides, the higher the volatile content of coal contained, the smaller the proportion of aromatic structure was, the more developed the pore structure was, resulting in the more easily oxidation and spontaneous combustion occurred.
[Abstract](2213) [FullText HTML](760) [PDF 1352KB](30)
Abstract:
Reasonably describing gas-liquid interaction force and bubble size distribution is the key to accurately simulate the hydrodynamic parameters of the bubble column. For the gas-liquid system, a new bubble breakup model was implemented into the population balance model (PBM) and coupled with the Euler two-fluid model. The gas-liquid two-phase flow in a bubble column with an inner diameter of 0.44 m and a height of 2.43 m was simulated. Firstly, the predicted values of bubble breakup rate and daughter bubble size distribution of the breakup model were verified. Then, the gas holdup and liquid axial velocity predicted by coupled model at different superficial gas velocities were compared with the experimental values. Moreover, the effect of lift to model (prediction result)was investigated. The results show that, both gas holdup and liquid axial velocity is improved in radial distribution when the lift force is included. The simulation value of the CFD-PBM coupled model have a good agreement with the experimental data in low and high superficial velocity. Both the turbulent dissipation rate in the reactor and the interaction between the bubbles rise with an increase in superficial gas velocity, which makes the distribution range of bubble size is widened.
[Abstract](7872) [FullText HTML](3112) [PDF 892KB](5)
Abstract:
In this study, the salt-tolerant bacteria were used to degrade the organic matter and ammonia nitrogen in the shale field produced water. The degradation performance and membrane fouling characteristics of the anoxic reactor-membrane bioreactor (AR-MBR) and the separate MBR reactor were investigated. The difference between two reactors was that the AR-MBR system was provided with a filament filler to form an anoxic circumstance in front of the MBR reactor. The results showed that the degradation of the AR-MBR combined reaction system was better than that of the MBR reactor alone. The removal rates of TOC were 88% in AR-MBR and 80% in MBR, the removal rates of ammonia nitrogen were 90% and 75%, respectively.The transmembrane pressure(TMP) and the total membrane fouling rate of the AR-MBR was slower than that of the MBR reactor. The main reason was that the particle size of the floc in the AR-MBR reactor was larger than that in the MBR reactor, which was not easy to block the membrane pores. On the other hand, the soluble microbial products(SMP) and extracellular polymeric substances (EPS) content was lower in AR-MBR reactor than that of the MBR reactor, while the protein to polysaccharide concentration ratio (PN/PS) was higher, the reduction of fouling substance on membrane alleviated the membrane fouling phenomenon.
[Abstract](971) [FullText HTML](252) [PDF 1116KB](13)
Abstract:
Cobalt selenide is considered to be an ideal anode material for lithium-ion batteries because of its good lithium-ion insertion/extraction capability. However, due to large volumetric expansion upon cycling and insulating nature, the performance of cobalt selenide is limited. In this study, we obtained CoSe2-C/C-PAN by coating CoSe2-C polyhedrons with polyacrylonitrile (PAN) in N2 atmosphere. The CoSe2-C polyhedrons were successfully synthesized using Co-based zeolitic imidazolate framework (ZIF-67) as precursor through a two-step method, including carbonization of ZIF-67 and subsequent selenization. The resultant CoSe2-C/C-PAN presents high specific capacity and excellent cycling stability with an initial discharge capacity of 1 440 mAh/g at 0.2 A/g and a reversible capacity of 653 mAh/g at 1 A/g after 200 cycles as anode material of Li-ion battery. The excellent battery performance of CoSe2-C/C-PAN should be attributed to the synergistic effect of nanostructured CoSe2 and carbon materials, in which the nanostructured CoSe2 possesses high reactivity towards lithium-ions and the carbon can provide a continuous conductive matrix to facilitate the charge transfer and an effective buffering to mitigate the structure variation of CoSe2 during cycling. And such significantly enhanced electrochemical performance should be ascribed to the improved electrical conductivity and structure stability of C-PAN.
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2020, 46(5): 579-588.   doi: 10.14135/j.cnki.1006-3080.20190527002
[Abstract](699) [FullText HTML](498) [PDF 1352KB](41)
Abstract:
The magnetic polymer brushes contain a magnetic core and a polymer brush shell, which is a new type of core-shell structure composing of polymer chains densely grafted to the surface of the magnetic cores at one end. The magnetic core could be either based on single magnetic nanoparticle or composite materials, where the matrix to encapsulate the magnetic nanoparticles could be inorganic materials like silica or organic materials like polystyrene or poly(methyl methacrylate). The introduction of magnetic nanoparticles enables great convenience and functionality in the preparation process and practical application of polymer brushes. Functional magnetic polymer brushes could be recycled, separated, and purified by easy operation under external magnetic field. In the last decade, with the continuous development of preparation strategies of magnetic nanospheres and surface modification techniques of nanospheres, magnetic polymer brushes have been systematically studied on structure design, functionality and applications. Magnetic polymer brushes have broad application prospects in protein adsorption and purification, bioimaging, specific detection, and catalytic enhancement, etc. This paper reviews the latest research progress in magnetic polymer brushes, and the future development direction is also anticipated.
2020, 46(5): 589-597.   doi: 10.14135/j.cnki.1006-3080.20190430002
[Abstract](599) [FullText HTML](340) [PDF 1242KB](12)
Abstract:
The associated fluorine impurities in phosphate ore seriously affect the quality of the phosphoric acid during the wet-process phosphoric acid production. Tributylphosphate (TBP) was used as an extractant, sulfonated kerosene (hereinafter referred to as kerosene), isoamylol, diisopropyl ether were used as the diluent, respectively. The extraction mechanism was investigated by quantum chemical calculation, Flourier transform infrared spectroscopy (FT-IR), 19F nuclear magnetic resonance (19F-NMR) and composition of extraction complexes. The binding energy of TBP-kerosene with HF was calculated by implicit solvent model, while TBP-isoamylol and TBP-diisopropyl ether with HF were calculated by explicit solvent model. The results show that the binding energy of above three extraction systems are −13.399 kJ/mol, −19.199 kJ/mol, and −20.556 kJ/mol, respectively. Analyses of the FT-IR spectra of the loaded organic phases indicate the TBP extraction of HF is occurred by the association of hydrogen bonding, while the extraction of HF using isoamylol and dissopropyl ether is realized through hydrogen bonding. The main form of fluoride in organic solvent was HF·TBP according to the 19F-NMR spectra. The compositions of the extraction complexes in the solvent of kerosene, isoamylol, diisopropyl ether were determined to be 0.9HF·TBP, 1.4HF·TBP and 1.6HF·TBP, respectively. The effects of different fluorine forms in wet-process phosphoric acid on defluorination rate were studied. It can be concluded that CaF+ and \begin{document}${\rm{FeF}}_x^{3-x}$\end{document} (x=1—6) have a slight effect on the selectivity coefficient and defluorination rate. MgF+ can be effectively extracted from the organic solvent by TBP, and the selectivity coefficient is increased with the increase of Mg2+ concentration in the solution. The TBP extraction of \begin{document}${\rm{SiF}}_6^{2-}$\end{document} and \begin{document}${\rm{AlF}}_x^{3-x}$\end{document} were moderated, indicating that the defluorination of wet process phosphoric acid needs to be achieved by pretreatment or other methods when the contents of active silica and aluminum oxide in phosphate rock are high.
2020, 46(5): 598-607.   doi: 10.14135/j.cnki.1006-3080.20190430003
[Abstract](285) [FullText HTML](273) [PDF 2369KB](8)
Abstract:
The medium-temperature or low-temperature alkaline leaching method of spodumene ore is an environmentally friendly laboratory technology being explored. The low concentration of lithium and high concentration of impurity ions in the leaching solution make it impossible to prepare lithium carbonate. Herein, the preparation of low-solubility and high-value lithium phosphate (\begin{document}${\rm{L}}{{\rm{i}}_{\rm{3}}}{\rm{P}}{{\rm{O}}_{\rm{4}}}$\end{document}) is proposed. The solubility of \begin{document}${\rm{L}}{{\rm{i}}_{\rm{3}}}{\rm{P}}{{\rm{O}}_{\rm{4}}}$\end{document} in alkaline solution system was determined. The effect of process conditions on the yield and particle size of \begin{document}${\rm{L}}{{\rm{i}}_{\rm{3}}}{\rm{P}}{{\rm{O}}_{\rm{4}}}$\end{document} was investigated, as well as the influences of impurity including K, Si, Al on the purity, morphology and size of \begin{document}${\rm{L}}{{\rm{i}}_{\rm{3}}}{\rm{P}}{{\rm{O}}_{\rm{4}}}$\end{document}. The mechanism indicates that the synergy of ion-selective-adsorption on the crystal surface and ion-intercalation in the crystal lattice are responsible for the effects. Central composite design (CCD), a kind of response surface methodology, was employed to explore the effects of reaction temperature, lithium concentration, dosage of sodium phosphate and feeding rate. The optimal conditions were 80 ℃, 1.60 g/L of Li+ concentration, 130% of Na3PO4 dosage and 10 mL/min of feed speed, respectively. Under the conditions, the optimal yield and the average particle size were predicted to be 97.37% and 18.57 μm, respectively, while the corresponding experimental results were 96.85% and 18.70 μm, respectively. The errors between the predicted and experimental values were small.
2020, 46(5): 608-612.   doi: 10.14135/j.cnki.1006-3080.20190809004
[Abstract](366) [FullText HTML](249) [PDF 937KB](6)
Abstract:
Metal-organic frameworks (MOFs) are a new series of porous materials with some impressing physical and chemical properties such as ultrahigh porosity (up to 90% free volume) and enormous specific surface areas. MOFs show great potential applications in the field of separation, adsorption, catalysis, biotechnology and electronics. Carbon nanotubes (CNTs) are cylindrical molecules that consist of rolled-up sheets of single-layer carbon atoms (graphene). In this work, Polyvinyl alcohol (PVA) composite membranes were fabricated and simultaneously modified by MOFs and CNTs. The physic-co-chemical structures and separation properties of the as-synthesized membranes were measured by field emission scanning electron microscopy, Fourier transform infrared spectoroscopy and pervaporation dehydration of isopropanol aqueous solutions. The results showed that MOFs and CNTs could efficiently change the structures and separation properties of the PVA composite membranes. The permeation flux of the modified PVA composite membranes increased while the separation selectivity decreased when the amount of MOFs increased. It is clear that a modified PVA composite membrane with excellent properties can be obtained when adding proper CNTs and MOFs amounts.
2020, 46(5): 613-620.   doi: 10.14135/j.cnki.1006-3080.20190512002
[Abstract](7604) [FullText HTML](1855) [PDF 1204KB](7)
Abstract:
A chain extender, styrene-maleic anhydride copolymer SMA-700, was mixed with recycled polyamide 6/carbon fiber composites (r-PA6/CF10) with a twin-screw extruder. The rheological properties, mechanical properties, morphology, crystalline structure, non-isothermal crystallization and subsequent melting behaviors of the resulting r-PA6/CF10 composites were investigated. The results show that SMA-700 has a remarkable chain extension effect on r-PA6/CF10 composites, and can significantly improve the processing performance of r-PA6/CF10. With the increase of mass fraction of SMA-700, the melt mass flow rate of r-PA6/CF10 decreases gradually. Meanwhile, the apparent viscosity and melt pseudo-plasticity of r-PA6/CF10 will increase with the increase of mass fraction of SMA-700. Mechanical tests show that incorporation of chain extender can simultaneously improve the tensile strength and flexural strength of r-PA6/CF10 composites. SMA-700 mass fractions of 1% and 2% maximizes the tensile strength (125.4 MPa) and flexural strength (182.3 MPa) of the r-PA6/CF10 composites, respectively. The impact strength decreases with increased mass fraction of SMA-700. Scanning electron microscopy (SEM) used suggests that there is no phase separation between SMA-700 and r-PA6 matrix, implying a good compatibility between SMA-700 and r-PA6. Non-isothermal crystallization and subsequent melting behaviors characterized by differential scanning calorimetry (DSC) show that when the mass fraction of SMA-700 is 1%, the nucleation effect of SMA-700 may increase the crystallization rate and crystallinity of the r-PA6 matrix. However, with an excessive amount of SMA-700, both the crystallization rate and crystallinity of r-PA6 drop, and the perfection degree of α crystal form of r-PA6 decreases simultaneously.
2020, 46(5): 621-630.   doi: 10.14135/j.cnki.1006-3080.20190625002
[Abstract](341) [FullText HTML](302) [PDF 1258KB](4)
Abstract:
Silica nanocapsules were synthesized in miniemulsion by using the surface of miniemulsion droplets as a template for the hydrolysis and condensation of tetraethoxysilane. In this study, we successfully used gemini emulsifier octenidine·2HCl (OCT) to encapsulate tea tree oil (TTO) in the core of silica nanocapsules (SINC-OCT/TTO). Then, we synthesized the silica nanocapsule (SINC-TTO) in the same way, in which only OCT was replaced with another emulsifier cetyltrimethylammonium chloride (CTAC). We compared the SINC-OCT/TTO with SINC-TTO in the structure and properties. Fourier transform infrared (FT-IR), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and thermogravimetric analysis (TGA) were used to characterize the structure of the nanocapsules. The specific surface areas and pore size of the SINCs were characterized with N2 absorption-desorption. The hydrodynamic diameter of the capsules was evaluated by dynamic light scattering(DLS). The results showed that the content of TTO loaded in SINCs, hydrodynamic diameter, specific surface area and pore size of SINCs were controlled by the type of surfactant. The hydrodynamic diameter of the two kinds of nanocapsules were 67.36 nm and 121.7 nm, respectively, and the specific surface areas were 289 m2/g and 437 m2/g, respectively. The mass fraction of TTO in SINC-OCT /TTO (47.7%) is higher than that in SINC-TTO (33.3%). The results of fractional inhibitory concentration index showed that TTO combined with OCT had synergistic antibacterial effects on S. aureus and had accumulative antibacterial effect on E. coli. The antibacterial experiment results of nanocapsules confirmed that the antibacterial effect of SINC-OCT/TTO was much higher than that of SINC-TTO.
2020, 46(5): 631-641.   doi: 10.14135/j.cnki.1006-3080.20190514001
[Abstract](6572) [FullText HTML](1942) [PDF 1402KB](22)
Abstract:
To explore the relationship between drug grafting ratio of polymeric prodrugs and their drug-loading efficiency, a model polymeric prodrug, methoxy poly(ethylene glycol)- b -poly(ε-caprolactone- co -piperilactone- g -5-aminolevulinic acid) (mPEG- b -P(CL- co -APIL)), was prepared. This prodrug was used as a drug carrier of 5-aminolevulinic acid (5-ALA) through both covalent bonding and non-covalent embedding. Molecular dynamics (MD) was used to calculate the compatibility of the polymeric prodrug with 5-ALA and H2O molecules, and to predict the relationship between the drug grafting ratio and drug loading. On calculation, the Flory-Huggins interactional parameter was decomposed into van der Waals force components and electrostatic force components for analyzing the effect of 5-ALA grafting ratio on the polymeric prodrug carrier. Dissipative particle dynamics simulation (DPD) was used to explore and observe the morphology of the drug-loaded micelles and the concentration state of the drug molecules. Computational simulation results showed that the compatibility between polymeric prodrug and 5-ALA improved with an increasing drug grafting ratio, leading to a prediction that the drug loading efficiency of polymeric drug would improve as the drug grafting ratio increased. Meanwhile, the DPD simulation showed that the polymeric prodrug self-assembled into spherical micelles in H2O.The density distribution of drug molecules suggested that the drug concentration in the core of the micelle was high because of a higher drug grafting ratio. All the simulation results suggested the feasibility of improving drug loading efficiency by increasing drug-molecule grafting ratios. This research offers guidance for the design and development of drug carriers.
2020, 46(5): 642-652.   doi: 10.14135/j.cnki.1006-3080.20190505001
[Abstract](902) [FullText HTML](328) [PDF 1613KB](9)
Abstract:
The photocyclization quantum yield of traditional diarylethene systems is always limited to 50% (mole fraction) due to the inseparability of the parallel (p-) and anti-parallel (ap-) conformers. However, it is possible to block the conversion between the two conformers by increasing steric hindrance between the side aryl groups and ethene bridge, thus enhancing the photocyclization quantum yields. Herein, based on the sterically-hindered bisbenzo(thiadizole) ethene bridge, we fully compared the steric effect of side thiophene rings, and got insight into the electronic effects of substitution groups, like the electron-donating, such as anisole unit and the electron-withdrawing pyridine units. The parallel and antiparallel conformers of compounds 1 and 3 can be separated successfully upon introducing the sterically hindered methyl group to the β-position of thiophene rings, thus greatly improving their photocyclization quantum yields, higher than 50% (mole fraction). Moreover, the incorporated steric hindrance of β-methyl groups on thiophene rings results in lower thermal stability of 1c and 3c. In contrast, 2c and 4c show good thermal stability which can be attributed to the relatively small steric hindrance and intramolecular hydrogen bond. When compared with the electronic effects, the electron-withdrawing effects of pyridine units brings forth the higher thermal bleaching rate of 1c than that of 3c containing the electron-donating anisole units.
2020, 46(5): 653-664.   doi: 10.14135/j.cnki.1006-3080.20190821001
[Abstract](7120) [FullText HTML](1726) [PDF 1472KB](10)
Abstract:
Halogen-free surface active ionic liquid (SAIL), 1-butyl-3-methylimidazolium alkyl sulfate ([C4mim][C12SO4]), was synthesized through ion exchange reaction. The photo responsive system of Gemini surfactant 12-3-12·2Br (Gemini12-3-12)/[C4mim][C12SO4]/ trans -OMCA/H2O was constructed by mixing [C4mim][C12SO4] with Gemini12-3-12, followed by an addition of photosensitive molecules, trans -o-methoxy cinnamate ( trans -OMCA). The photo-responsive behaviors of aqueous two-phase system (ATPS), a specific single-phase system and the anisotropic phase system in the mixture of Gemini12-3-12/[C4mim][C12SO4]/ trans -OMCA/H2O were studied by TEM, UV-vis and dynamic light scattering (DLS). The results show that the mixed system displays good photo responsiveness. For the aqueous two-phase system, in which spherical micelle and wormlike micelle coexist, UV irradiation for a certain period of time promotes the fusion of the spherical-micelle phase and wormlike-micelle phase into another single wormlike-micelle phase. For the single-phase vesicle system, it is separated into a two-phase system of spherical micelle and wormlike micelle after UV irradiation, and the system gradually merges into a single wormlike-micelle phase when the irradiation time is prolonged. The anisotropic system becomes isotropic after exposure to UV irradiation. It is suggested that the macro-phase behaviors of the system can be changed by UV irradiation and the system can undergo a photo-induced phase separation as well as combination.
2020, 46(5): 665-671.   doi: 10.14135/j.cnki.1006-3080.20191128001
[Abstract](644) [FullText HTML](275) [PDF 818KB](4)
Abstract:
Stimulus-responsive molecular shuttles have unique shuttle movement capabilities in mechanically interlocked nanosystems, but how to choose appropriate and efficient control methods in a complex host-guest system has always been a difficult problem to be solved. Photochemical stimulation is considered to be the most promising and most valuable mode for regulating molecular machines, because light control is not only accurate in time and space, but also has the advantages of simplicity, cleanness and no pollution. Light-induced proton transfer is a novel regulation strategy that can be applied in the host-guest system of acid-base response. Based on the photo-induced proton transfer mechanism, a [2]rotaxane R molecular shuttle with photoacid (merocyanine, MEH) controlled response was successfully designed and synthesized, and its structure was confirmed by 1H-NMR, 13C-NMR and mass spectrometry. Before and after exposing to light, the UV absorption and 1H-NMR spectra of the system were compared by means of UV-Vis and variable-temperature 1H-NMR spectroscopy. The results showed that in the presence of photoacid (MEH) at 419 nm, the cyclobis (paraquat-p-phenylene) (CBPQT4+ ) macrocycle was located on one side of the naphthalene, and the [2]rotaxane R molecular shuttle was in a "stationary" state; while in the dark for 12 h, the CBPQT4+ macrocycle shuttled between the two naphthalene components, and the [2]rotaxane R molecular shuttle was in a "moving" state. This work offers a strategy for conformational transmission in molecular level.
2020, 46(5): 672-679.   doi: 10.14135/j.cnki.1006-3080.20190629003
[Abstract](669) [FullText HTML](380) [PDF 1011KB](7)
Abstract:
Poria cocos, called FuLing in Chinese, is a traditional Chinese medicinal herb. Poria cocos polysaccharides (PCPs) were extracted from Poria cocos collected from different origins through water extraction and alcohol precipitation. High performance liquid chromatography (HPLC) was applied to establish the fingerprint for 16 batches PCPs. A macrophage cell line RAW274.7 was incubated in different concentrations of 16 batches PCPs. The immunological activity was evaluated based on the proliferation activity of cells as determined by MTT assay and NO production. The immunological activity of 16 batches PCPs were introduced into orthogonal partial least squares analysis to investigate the correlation between monosaccharide compositions and immunological activity. The results showed that PCPs were composed of eight monosaccharides, which were Glc, Gal, Man, Fuc, GlcN, GlcA, Xyl and Ara, respectively. The similarity analysis showed that the similarity of the 16 batches PCPs ranged from 0.980 to 1.000. All the 16 PCPs showed well immunological activities, according to the in vitro activity evaluations. Mouse macrophages were stimulated with different concentrations of PCPs. NO production increased with the increase of PCPs concentration, which was higher than that of the blank. According to the orthogonal partial least squares analysis, all the monosaccharides from PCPs had relationship with immunological activity. Gal, Ara, Man and Glc were positively correlated with the immunological activity of mouse macrophages, while Fuc, GlcA, GlcN and Xyl were negative correlated with the immunological activity of mouse macrophages. Particularly, Glc, Gal and Man in PCPs significantly contributed to the NO production from mouse macrophages.
2020, 46(5): 680-687.   doi: 10.14135/j.cnki.1006-3080.20190601001
[Abstract](356) [FullText HTML](237) [PDF 1121KB](5)
Abstract:
P-glycoprotein (P-gp) is the first transporter that is found to be associated with the sensitivity of cells to chemotherapeutic drugs. The main function of P-gp is to exclude exogenous substances from cells to prevent the body from absorbing harmful substances. Therefore, it is one of the self-defense and protection mechanisms under the physiological state of the body. However, this defense mechanism of P-gp protein also leads to decrease in the concentration of some drug molecules in cells, leading to multidrug resistance. The multidrug resistance of cells is one of the main reasons that leads to the failure of chemotherapy. Therefore, inhibiting the efflux function of P-gp is one of the effective methods to reduce or even reverse multidrug resistance of cells. Quercitrin was a kind of flavonoid monomer compound with low biological toxicity, good water solubility, and weak P-gp inhibitory activity. In order to enhance the P-gp inhibitory activity of Quercitrin, we synthesized Quercitrin metal complexes Cu-Quercitrin and Zn-Quercitrin, and their P-gp inhibitory activities were investigated at the cellular level. Cu-Quercitrin could increase the accumulation of rhodamine 123 and doxorubicin in MCF-7/ADR cells, and improve the cytotoxicity of doxorubicin. In fact, the effect of Cu-Quercitrin was significantly better than that of P-gp inhibitor verapamil. In contrast, Cu-Quercitrin had no effect on the accumulation of rhodamine 123 and doxorubicin in normal MCF-7 cells, suggesting that Cu-Quercitrin could inhibit the transport function of P-gp. Compared with the Cu-Quercitrin, Zn-Quercitrin had no significant effect on the accumulation of P-gp substrates rhodamine 123 and doxorubicin in drug-resistance MCF-7/ADR cells. Further studies showed that Cu-Quercitrin had no effect on the expression of P-gp, but reduced the content of adenosine triphosphate（ATP）in drug-resistant cells. Therefore, Cu-Quercitrin increased the accumulation of anti-cancer drugs in drug-resistant cells by reducing the content of ATP and inhibiting the transport function of P-gp, which was expected to alleviate the multi-drug resistance of cells mediated by P-gp. This study indicated that Quercitrin metal complexes, Cu-Quercitrin, could be a novel P-gp inhibitor. Meanwhile, metal complexes with diverse structures and abundant ligands were expected to be candidate compounds for effective P-gp inhibitors.
2020, 46(5): 688-693.   doi: 10.14135/j.cnki.1006-3080.20190806001
[Abstract](2211) [FullText HTML](882) [PDF 1057KB](26)
Abstract:
Glutathione (GSH), one of the thiol short peptide in organisms, is widely used in medicine, food additive, health care and cosmetic industries. In this study, a two-enzyme cascade consisting of bifunctional glutathione synthetase (GshF) and polyphosphate kinase (PPK) was constructed for ATP-regenerating synthesis of GSH. As the catalytic substrate of PPK, polyphosphate (polyP) was used to provide energy in the reaction. The efficient soluble expressions of GshF and PPK were achieved when induced at a low temperature of 18 °C. After purification, the two enzymes were coupled together to synthesize GSH in one pot. It was found that high concentration of MgCl2 inhibited the production of GSH due to the chelation with polyP. The optimal concentration ratio of polyP to MgCl2 was 30∶45. At 0.5 mmol/L ADP, the reaction achieved the highest efficiency for GSH formation. The optimal temperature for the two-enzyme reaction was 45 °C, achieving a high yield of 78% based on added L-cysteine. The optimal temperature for GSH synthesis was relatively high, because the activities of GshF and PPK could increase with temperature. The enzyme ratio in the system was further investigated. The production of GSH was improved at higher concentration of PPK, indicating that the ATP-regenerating reaction was a limit step in the reaction. At the optimal ratio of 4 g/L PPK and 1 g/L GshF, the titer of GSH reached (58 ± 3.3) mmol/L with a productivity of (19.3 ± 1.1) mmol/L/h at 3 h, which achieved the reported highest production of GSH. Using the low-cost substrate of polyP to supply energy, the efficient cascade reaction provided a potential application for large-scale enzymatic production of GSH.
2020, 46(5): 694-701.   doi: 10.14135/j.cnki.1006-3080.20190730001
[Abstract](2667) [FullText HTML](956) [PDF 833KB](22)
Abstract:
The variable neighborhood search algorithm may have difficulty in searching a better feasible solution in some neighborhoods for a long time in later stage. Aiming at the shortcoming, this paper proposes an adaptive variable neighborhood search algorithm based on neighborhood selection probability. The proposed algorithm can adjust the selection probability in some neighborhoods adaptively according to the optimization circumstance of this neighborhood such that the optimization efficiency can be improved. This paper designs two select probability update methods and analyzes their characteristics. By setting the minimum selection probability, the selection probability may be avoided to reduce to zero and the diversity of the neighborhood can be ensured. Due to battery capacity limitations and charging requirements, the optimization problem of the electric vehicle route is more complicated than the traditional vehicle route problem. By modeling and analyzing the large-scale electric vehicle routing problem under the actual urban distribution logistics, this paper propose an efficient initial solution generation algorithm according to the geographic location and the time window of the service customer. Some neighborhood operators using segmentation-exchange, 2-opt, and relocation are designed to achieve the adaptive variable neighborhood search. Finally, the simulation experiments with different scales data are made. It is shown from the results that the variation curves of the two select probability update methods have the same tendency, which verifies the rationality of minimum selection probability vector setting. Compared with the traditional variable neighborhood search algorithm, the proposed adaptive variable neighborhood search algorithm can effectively jump out of the local optimal solution and reduce the logistical cost under urban distribution.
2020, 46(5): 702-708.   doi: 10.14135/j.cnki.1006-3080.20190731002
[Abstract](6435) [FullText HTML](1820) [PDF 878KB](4)
Abstract:
Partial transfer sequence (PTS) is an effective method for filter bank multicarrier (FBMC) to reduce peak-to-average power ratio (PAPR). However, PTS method selects the optimal phase factor via exhaustive search, which inevitable results in high computational complexity. In order to overcome this shortcoming, this paper presents a new PTS-based method. Firstly, based on the traditional PTS segmentation method, this paper introduces an odd-partial transfer sequence(OPTS) segmentation method, which uses staggered segmentation for odd subblocks and random segmentation for even subblocks. By combining the advantages of staggered segmentation and random segmentation, this proposed method can effectively improve the PAPR performance of the system, meanwhile, reduce the computational complexity. Secondly, this paper proposes a scaled particle swarm optimization (SPSO) algorithm by incorporating the scaling factor into the traditional PSO algorithm. It is known that the conventional particle swarm optimization (PSO) algorithm has a slow convergence rate in the iteration process and is prone to fall into local optimal in high-dimensional space. Aiming at the above shortcoming, this paper proposes an improved PSO algorithm, SPSO algorithm, whose main idea is to use the scaling factor to control the particle speed, and obtain better PAPR performance with lower computational complexity and faster convergence speed. It will slightly increase PAPR value via integrating SPSO algorithm into OPTS and can attain better performance in terms of complexity, and significantly improve the spectrum utilization. Finally, simulation results verify the effectiveness of the new method.
2020, 46(5): 709-714.   doi: 10.14135/j.cnki.1006-3080.20190602001
[Abstract](613) [FullText HTML](302) [PDF 1194KB](4)
Abstract:
Characterizing the cross-section quality after blanking test is a difficult task in the punching industrial field. At present, the main evaluation method for the cross-section quality is to measure the relative ratio of smooth-sheared length and fracture length. However, the relative length ratio can not reveal the complexity of the fracture surface and can not fully characterize the details of the cross section profile. As a promising theory, fractal theory has been widely used in the metal research field and has a great advantage on the quantitative characterization of the quality of blanking cross sections. Based on the Mandelbrot fractal theory, the relative length ratios of different blanking cross sections were measured and the fractal dimension of each fracture surface were calculated. The results show that with the decrease of the fractal dimensions of the blanking cross section, the quality of fracture surface becomes better. Numerical simulations of the blanking process show that the smooth fracture zone is determined by the shear stress, and the fracture zone is determined by the tensile stress. The upper limit of fractal dimension for the blanking section can be estimated by measuring the fractal dimension of the fracture profile of tensile specimen.
2010, (3).
[Abstract](9443) [PDF 653KB](5200)
2011, (6): 770-774.
[Abstract](9521) [PDF 1759KB](3692)
2009, (5): 798-802.
[Abstract](8830) [PDF 479KB](3100)
2011, (3): 261-264.
[Abstract](9940) [PDF 496KB](2999)
2012, (2): 186-190.
[Abstract](9197) [PDF 2108KB](2576)

2009, (6): 860-865.
[Abstract](9384) [PDF 676KB](2559)
2011, (6): 775-781.
[Abstract](9081) [PDF 1775KB](2551)
2012, (1): 107-115.
[Abstract](9479) [PDF 2656KB](2540)

2009, (5): 750-755.
[Abstract](9210) [PDF 673KB](2455)

2009, (3): 435-441.
[Abstract](9500) [PDF 721KB](2429)