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Journal of Forestry Research 2016年第1期27卷 167-174页

作者： Lin Zhang Gang Wei Yang liu Yuangang Zu Qinghui gai Lei Yang Key Laboratory of Forest Plant Ecology Ministry of Education Northeast Forestry University

We evaluated the hypoglycemic and antioxi- dant effects of the total alkaloids of leaves and twigs of Catharanthus roseus Linn. （CTA） in streptozotocin （STZ）- induced diabetic rats. The hypoglycemic effect was mea- sured by blood glucose and plasma insulin level. Oxidative stress was measured in heart, liver and kidney by levels of antioxidant markers, free radical scavengers and lipid peroxides i.e. superoxide dismutase （SOD）, catalase （CAT）, glutathione （GSH） and thiobarbituric acid reactive substances （TBARS）. Biochemical parameters, i.e. aspar- tate aminotransferase （AST）, alanine aminotransferase （ALT）, alkaline phosphate （ALP） were observed in diabetic control and treated rats. Oral administration of CTA for 30 days was followed by a significant （P 〈 0.05） decrease in fasting blood glucose and increase in insulin level as compared with untreated diabetic rats. Also it significantly （P 〈 0.05） reduced ALT, AST and ALP. The treatment also resulted in significant （P 〈 0.05） reductions in GSH, SOD, CAT, and decrease in TBARS in the heart, liver and kidney of diabetic rats. The results suggest that CTA can effectively normalize the impaired antioxidant status in STZ-induced diabetes in a dose-dependent *** exerted rapid protective effects against lipid peroxi- dation by scavenging of free radicals and reducing the risk of diabetic complications.

关键词： Antihyperglycemic activity Antioxidantactivity Catharanthus roseus Streptozotocin-induceddiabetic rats Total alkaloids

Amino-acids-functionalized M13-assisted synthesis of silver and silver sulfide nanoparticles

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Rare Metals 2023年第10期42卷 3532-3536页

作者： Jing Chen Juan Du Song-mei Li Jian-Hua liu mei Yu School of Materials Science and Engineering Beihang UniversityBeijing100191China

Bio-mineralization has been explored to synthesize nanomaterials with exquisite structures and amazing ***-acids-functionalized filamentous M13 virus was applied as a scaffold for the synthesis of silver and silver sulfide *** is interesting to find that the binding affinity between filamentous M13virus and silver ions can be effectively improved after a friendly modification by amino *** the same time,amino-acids-modified filamentous M13 virus also serves as a dispersant to decrease the size and increase the stability of silver *** silver and silver sulfide nanoparticles with monodispersed size and uniform morphology can be fabricated by the direction of amino-acidmodified filamentous M13 *** successful synthesis of silver sulfide nanoparticles on amino-acids-modified filamentous M13 virus suggests that this approach is highly efficient to fabricate not only metal nanoparticles,but also binary or multinary compounds.

关键词： Amino acids Filamentous M13 virus Modification Ag nanoparticles

On engineering game theory with its application in power systems

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Control Theory and Technology 2017年第1期15卷 1-12页

作者： Shengwei mei Wei WEI Feng liu Department of Electrical Engineering and Applied Electronics Technology Tsinghua Universily Beijing 100084 China State Key Laboratory of Control and Simulation of Power Systems and Generation Equipments Tsinghua University Beijing 100084 China

Due to its capability of solving decision-making problems involving multiple entities and objectives, as well as complex action sequences, game theory has been a basic mathematical tool of economists, politicians, and sociologists for decades. It helps them understand how strategic interactions impact rational decisions of individual players in competitive and uncertain environment, if each player aims to get the best payoff. This situation is ubiquitous in engineering practices. This paper streamlines the foundations of engineering game theory, which uses concepts, theories and methodologies to guide the resolution of engineering design, operation, and control problems in a more canonical and systematic way. An overview of its application in smart grid technologies and power systems related topics is presented, and intriguing research directions are also envisioned.

关键词： Decision making engineering game theory power system smart grid technology

On expansion of estimated stability region:Theory,methodology,and application to power systems

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Science China(Technological Sciences) 2011年第6期54卷 1394-1406页

作者： liu Feng WEI Wei mei ShengWei State Key Laboratory of Power Systems Department of Electrical Engineering Tsinghua University 100084 Beijing China

The expansion of the estimated stability region plays an important role in the stability analysis of nonlinear ***,current literatures have not provided a complete mathematical description for this *** paper reveals that essentially the enlargement or the compression of the estimated stability region results directly from the diffeomorphism map,which is induced by the flow contained in the stability *** proving that any integration algorithm with an order higher than one can approximately trace the flow of the system,a generalized methodology is proposed to construct various algorithms to realize the enlargement or the compression of the estimated stability *** this methodology,two new algorithms based on symbolic calculation are suggested to reduce the computational ***,this methodology is applied to construct a scalable numerical algorithm to calculate the critical clearing time(CCT) of the power system for given *** on the IEEE 10-machine 39-bus system show that the computational results coincide well with the step-by-step simulation with high accuracy.

关键词： nonlinear system stability region power systems transient stability analysis

Preparation of Monoclonal Antibody and Development of Enzyme-linked Immunosorbent Assay Specific for Escherichia coli O157 in Foods

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Biomedical and Environmental Sciences 2005年第4期18卷 254-259页

作者： ZHI-JING ZHAO XIU-mei liu National Institute of Nutrition and Food Safety Chinese Center for Disease Control and Prevention Beijing 100050 China

To prepare monoclonal antibodies （MAb） and antisera specific for Escherichia coli （***） O157, and to develop a sandwich enzyme-linked immunosorbent assay （ELISA） to detect Eocoli O157 in foods. Methods Spleen cells from BALB/c mice immunized with the somatic antigen of *** O157：H7 were fused with routine Sp2/0 myeloma cells. The hybridoma cell line specific for *** O157 was established after having been subcloned. Antisera specific for *** O157 was prepared by intravenous injection into New Zealand rabbits with a stain of *** O157：H7. The sandwich ELISA was developed with the polyclonal antibody as the capture antibody and the MAb 3A5 as the detection antibody. The inoculated ground poultry meat and pasteurized miLk were tested to confirm efficiency of the method. Results MAb 3A5 specific for *** O157 and O 113：H21 belonged to subtype IgM. The ascetic titers of the antibody was 1：1× 10^6. No cross-reactivity of the MAb was observed with strains of Salmonella spp, Yersinia enterocolitica, Shigella dysenteriae, etc. The purified polyclonal antibody had a titer of 1： 1× 10^5 with *** O 157. The detection limit of this sandwich ELISA was 10^3- 10^4 cfu *** O157/mL in pure culture with a high specificity, which was characterized by every non-O157 strain with negative response. With 10h enrichment procedure, *** O157：H7 recovered well from inoculated ground poultry meat and pasteurized milk at levels of 0.1 cfu/g and 0.1 cfu/mL. Conclusion MAb 3A5 specific for *** O 157 and O 113：H21 can be produced by immunizing BALB/c mice with a strain of *** O157：H7. Then a sandwich ELISA can be developed with the polyclonal antibody as the capture antibody and the MAb 3A5 as the detection antibody. The method is proved to be a sensitive and specific technique to detect low number of *** O157 in food.

关键词： Escherichia coli O 157 Monoclonal antibody Polyclonal antibody ELISA

Synthesis and Characterization of Fluorinated Polyimide Derived from 3,3＇-Diisopropyl-4,4＇-diaminodiphenyl- 3＂,4＂-difluorophenylmethane

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Chinese Journal of Chemistry 2015年第10期33卷 1159-1166页

作者： Xiaohua Huang mei mei Chanjuan liu Xianglin Pei Chun Wei Key Laboratory of New Processing Technology for Nonferrous Metal & Materials Ministry of Education andSchool of Material Science and Engineering Guilin University of Technology Guilin Guangxi 541004 China Ministry of Education Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources School of Chemistry and Pharmaceutical Science Guangxi Normal University Guilin Guangxi 541004 China

A novel aromatic diamine monomer, 3,3＇-diisopropyl-4,4＇-diaminodiphenyl-3＂,4＂-difluorophenylmethane （PAFM）, was successfully synthesized by coupling of 2-isopropylaniline and 3,4-difluorobenzaldehyde. The aro- matic diamine was adopted to synthesize a series of fluorinated polyimides by polycondensation with various dian- hydrides： pyromellitic dianhydride （PMDA）, 3,3＇,4,4＇-biphenyltetracarboxylic dianhydride （BPDA）, 4,4＇-oxydiph- thalic anhydride （ODPA） and 3,3＇,4,4＇-benzophenone tetracarboxylic dianhydride （BTDA） via the conventional one-step method. These polyimides presented excellent solubility in common organic solvents, such as N,N-dimeth- ylformamide （DMF）, N,N-dimethyl acetamide （DMAc）, dimethyl sulfoxide （DMSO）, N-methyl-2-pyrrolidone （NMP）, chloroform （CHC13）, tetrahydrofuran （THF） and so on. The glass transition temperatures （Tg） of fluorinated polyimides were in the range of 260--306 ℃ and the temperature at 10% weight loss in the range of 474--502 ℃ Their films showed the cut-off wavelengths of 330--361 nm and higher than 80% transparency in a wavelength range of 385--463 nm. Moreover, polymer films exhibited low dielectric properties in the range of 2.76--2.96 at 1 MHz, as well as prominent mechanical properties with tensile strengths of 66.7--97.4 MPa, a tensile modulus of 1.7--2.1 GPa and elongation at break of 7.2%- 12.9%. The polymer films also showed outstanding hydrophobicity with the contact angle in the range of 91.2°--97.9°.

关键词： fluorinated polyimides solubility transparency dielectric constant

Features of Motion of Soliton Transported Bio-energy in Aperiodic α-Helix ProteinMolecules with Three Channels

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Communications in Theoretical Physics 2009年第1期51卷 170-180页

作者： PANG Xiao-Feng liu mei-Jie Institute of High-Energy Electronics University of Electronic Science and Technology of China Chengdu 610065 China International Center for Materials Physics Chinese Academy of Sciences Shenyang 110015 China

The structure aperiodicities can influence seriously the features of motion of soliton excited in the α-helix protein molecules with three channels. We study the influence of structure aperiodicities on the features of the soliton in the improved model by numerical simulation and Runge-Kulta method. The results obtained show that the new soliton is very robust against the structure aperiodieities including large disorder in the sequence of mass of the amino acids and fluctuations of spring constant, coupling constant, dipole-dipole interactional constant, ground state energy and chain-chain interaction. However, very strong structure aperiodieities can also destroy the stability of the soliton in the α-helix protein molecules.

关键词： structure aperiodicity soliton stability protein bio-energy Runge-Kulta method

Bio-energy in s-Helix Protein Molecules with Three Properties of Soliton-Transported Channels

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Communications in Theoretical Physics 2007年第2X期48卷 369-376页

作者： PANG Xiao-Feng liu mei-Jie Institute of Life Science and Technology University of Electronic Science and Technology of China Chengdu 610054 China International Center for Material Physics the Chinese Academy of Sciences Shenyang 110015 China

We study numerically the propagating properties of soliton-transported bio-energy excited in the a-helix protein molecules with three channels in the cases of the short-time and long-time motions and its features of collision at temperature T = 0 and biological temperature T = 300 K by the dynamic equations in the improved Davydov theory and fourth-order Runge-Kutta method, respectively. From these simulation experiments we see that the new solitons in the improved model can move without dispersion at a constant speed retaining its shape and energy in the cases of motion of both short-time or T = 0 and long time or T = 300 K and can go through each other without scattering in their collisions. In these cases its lifetime is, at least, 120 ps at 300 K, in which the soliton can travel over about 700 amino acid residues. This result is consistent with analytic result obtained by quantum perturbed theory in this model. In the meanwhile, the influences of structure disorder of a-helix protein molecules, including the inhomogeneous distribution of amino acids with different masses and fluctuations of spring constant, dipole-dipole interaction, exciton-phonon coupling constant and diagonal disorder, on the solitons are also studied by the fourth-order Runge-Kutta method. The results show that the soliton still is very robust against the structure disorders and thermal perturbation of proteins at biological temperature 300 K. Therefore we can conclude that the new soliton in the a-helix protein molecules with three channels is a possible carrier of bio-energy transport and the improved model is possibly a candidate for the mechanism of this transport.

关键词： bio-energy transport soliton protein molecule Runge-Kutta method thermal stabilization

Boundedness in a chemotaxis system with nonlinear signal production

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Applied Mathematics(A Journal of Chinese Universities) 2016年第4期31卷 379-388页

作者： liu Dong-mei TAO You-shan College of Information Science & Technology Dong Hua University Department of Applied Mathematics Dong Hua University

This work deals with the zero-Neumann boundary problem to a fully parabolic chemotaxis system with a nonlinear signal production function f（s） fulfilling 0 〈 f（s）〈 Ksα for all s 〉 0, where K and α are positive parameters. It is shown that whenever 0 〈 α 〈 2/n （where n denotes the spatial dimension） and under suitable assumptions on the initial data, this problem admits a unique global classical solution that is uniformly-in-time bounded in any spatial dimension. The proof is based on some a priori estimate techniques.

关键词： Keller-Segel model nonlinear signal production prevention of blow-up.

The Decision of Prime and Primary Ideal

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Acta Mathematicae Applicatae Sinica 2011年第4期27卷 595-600页

作者： Jin-wang liu Dong-mei LI School of Mathematics and Computing Sciences Hunan University of Science and Technology Xiangtan 411201 China School of Mathematical Science and Computing Technology Central South University Changsha 410083 China

We give more efficient criteria to characterise prime ideal or primary ideal. Further, we obtain the necessary and sufficient conditions that an ideal is prime or primary in real field from the Grobner bases directly.

关键词： Grobner basis prime ideal orimarv ideal