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Quartz crystal microbalance study of the kinetics of surface initiated polymerization

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Science China Chemistry 2009年第12期52卷 2307-2322,1-5页

作者： CHEN XinAn ZHANG YaoZhong HE JianAn XIONG ChunYang MENG YongHong jin gang MA HongWei Department of Biomedical Engineering College of EngineeringPeking UniversityBeijing 100871China National Microgravity Laboratory Institute of MechanicsChinese Academy of SciencesBeijing 100190China Suzhou Institute of Nano-Tech and Nano-Bionics Chinese Academy of SciencesSuzhou 215125China

Surface initiated polymerization (SIP) is a valuable tool in synthesizing functional polymer brushes,yet the kinetic understanding of SIP lags behind the development of its application. We apply quartz crystal microbalance (QCM) to address two issues that are not fully addressed yet play a central role in the rational design of functional polymer brushes,namely quantitative determination of the kinetics and the initiator efficiency (IE) of SIP. SIP are monitored online using QCM. Two quantitative frequencythickness (f-T) relations make the direct determination and comparison of the rate of polymerization possible even for different monomers. Based on the bi-termination model,the kinetics of SIP is simply described by two variables,which are related to two polymerization constants,namely a = 1/(kp,s,app-[M][R·]0) and b = kt,s,app/(kp,s,app[M]). Factors that could alter the kinetics of SIP are studied,including (i) the molecular weight of monomers,(ii) the solvent used,(iii) the initial density of the initiator,(iv) the concentration of monomer,[M],and (v) the catalyst system (ratio among the ingredients,metal,ligands,and additives). The dynamic nature of IE is also described by these two variables,IE = a/(a + bt). Instead of the molecular weight and the polydispersity,we suggest that film thickness,the two kinetic parameters (a and b),and the initial density of the initiator and IE be the parameters that characterize ultrathin polymer brushes. Besides the kinetics study of SIP,the reported method has many other applications,for example,in the fast screening of catalyst system for SIP and other polymerization systems.

关键词： surface initiated polymerization quartz crystal microbalance kinetics controlled living radical polymerization

Changes of chlorogenic acid content and its synthesis-associated genes expression in Xuehua pear fruit during development

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Journal of Integrative Agriculture 2017年第2期16卷 471-477页

作者： HE jin-gang CHENG Yu-dou GUAN Jun-feng GE Wen-ya ZHAO Zhe Institute of Genetics and Physiology Hebei Academy of Agricultural and Forestry Science Shijiazhuang 050051 P.R. China Plant Genetic Engineering Center of Hebei Province Shijiazhuang 050051 P.R. China

According to synthetic pathway of plant chlorogenic acid （CGA）, the expression patterns of genes encoding enzymes that are associated with CGA synthesis were studied in normally developed Xuehua pear fruit. The study demonstrated that CGA content in peel and flesh of Xuehua pear decreased as fruit development progressed, with a higher level in peel. The expression levels of PbPAL 1, PbPAL2, PbC3H, PbC4H, Pb4CL 1, Pb4CL2, Pb4CL6, PbHC T1 and PbHC T3 genes decreased in fruit, which was consistent with the pattern of variation in CGA content. That indicated that these genes might be key genes for influencing fruit CGA synthesis in Xuehua pear. However, Pb4CL7 gene expression profile is not consistent with variation of CGA content, hence, it may not be a key gene involved in CGA synthesis.

关键词： cinnamate 4-hydroxylase gene hydroxy cinnamoyl CoA shikimate/quinic acid hydroxycinnamoyl transferasegene p-coumarate 3'-hydroxylase gene 4-hydroxycinnamoyl-CoA ligase gene phenylalanine ammonia lyasegene Xuehua pear

Effects of penehyclidine hydrochloride on rat intestinal barrier function during cardiopulmonary bypass

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World Journal of Gastroenterology 2011年第16期17卷 2137-2142页

作者： Ying-Jie Sun Hui-Juan Cao Qiang jin Yu-gang Diao Tie-Zheng Zhang Department of Anesthesiology General Hospital ofShenyang Commend Shenyang 110840 Liaoning Province China

AIM:To test the ability of penehyclidine hydrochloride (PHC) to attenuate intestinal injury in a rat cardiopulmonary bypass (CPB) ***:Male Sprague-Dawley rats were randomly divided into six groups (eight each):sham-operated control;sham-operated low-dose PHC control (0.6 mg/kg);sham-operated high-dose PHC control (2.0 mg/kg);CPB vehicle control;CPB low-dose PHC (0.6 mg/kg);and CPB high-dose PHC (2.0 mg/kg).Blood samples were collected from the femoral artery 2 h after CPB for determination of plasma diamine oxidase (DAO),D-lactate and endotoxin ***,liver,mesenteric lymph nodes and lung were removed for biochemical *** tissue ultrastructure was examined by electron ***:In the sham-operated groups,high-and low-dose-PHC had no significant impact on the levels of DAO,D-lactate and endotoxin,or the incidence of intestinal bacterial translocation (BT).Serum levels of DAO,D-lactate,endotoxin and the incidence of intestinal BT were significantly increased in the surgical groups,compared with the sham-operated groups (0.543 ± 0.061,5.697 ± 0.272,14.75 ± 2.46,and 0/40 vs 1.038 ± 0.252,9.377 ± 0.769,60.37 ± 5.63,and 30/40,respectively,all P < 0.05).PHC alleviated the biochemical and histopathological changes in a dosedependent *** levels of DAO,D-lactate,and endotoxin and the incidence of intestinal BT in the high-dose PHC group were significantly lower than in the low-dose PHC group (0.637 ± 0.064,6.972 ± 0.349,29.64 ± 5.49,and 14/40 vs 0.998 ± 0.062,7.835 ± 0.330,38.56 ± 4.28,and 6/40,respectively,all P < 0.05).CONCLUSION:PHC protects the structure and function of the intestinal mucosa from injury after CPB in rats.

关键词： Penehyclidine hydrochloride Intestinal mucosa injury Cardiopulmonary bypass

Effects of size variation and spatial structure on plastic response of plant height to light competition

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Chinese Science Bulletin 2010年第12期55卷 1135-1141页

作者： CHEN ShuYan ZHANG JiaLin JIA Peng XU jin WANG gang XIAO Sa Key Laboratory of Arid and Grassland Ecology of Ministry of Education School of Life Science Lanzhou University Lanzhou 730000 China

Plants only interact with neighbors over restricted distances,so local conditions are of great significance for *** this study,a spatially-explicit,individual-based model was constructed to explore the effects of size variation and spatial structure on adaptive plasticity of plant height in response to light *** the model a plant maintains its height at an optimal value in order to maximize its growth rate,and this optimal height increases with the increase of the intensity of light competition experienced by the individual *** the spatial pattern of the population is non-uniform or there is size variation among individual plants,the height growth curves of individuals different from each other vary due to the differences in the local light environment,and there is also variation in the allocation of photosynthate to height growth among the individual *** is no ESS height or height growth strategy on which all plants will *** results indicate that the plasticity of plants' height growth reactions to the light competition should be considered at the individual level and they argue strongly for the importance of the spatial pattern and neighborhood effects in generating the diversity of heights and height growth strategies in plant population.

关键词：空间结构光响应竞争塑料株高空间分布格局变异单株生长曲线

Simulation of Climate Negotiation Strategies between China and the U.S. Based on Game Theory

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Advances in Climate Change Research 2014年第1期5卷 34-40页

作者： jin Zhu-gang CAI Wen-Jia WANG Can Center for Earth System Science Tsinghua University School of Environment Tsinghua University

Consensus and disagreements between China and the U.S. are the key factors influencing the direction that global climate negotiation is heading for. By taking into account the uncertainties of temperature increment and its impact on GDP growth, together with the positive, negative and spillover effects of climate change investment on utility, a strategic simulation model including China and the U.S. is developed. Based on utility and game theory, a sensitivity analysis is conducted. The results show that the first-mover disadvantage exists in the game, and the scale of each country＇s climate change investment under non-cooperative win-win basis for global cooperation, the technology transfer and funding to China scenario is too small to ensure the 2℃ simulation results also indicate that it target. To guarantee the stability and makes sense to assist and compensate

关键词： climate negotiation utility game theory strategy

A novel grey wolf optimizer and its applications in 5G frequency selection surface design

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Frontiers of Information Technology & Electronic Engineering 2022年第9期23卷 1338-1353页

作者： Zhihao HE gang jin Yingjun WANG National Engineering Research Center of Novel Equipment for Polymer Processing South China University of TechnologyGuangzhou510641China Key Laboratory of Polymer Processing Engineering of the Ministry of Education South China University of TechnologyGuangzhou510641China Guangdong Provincial Key Laboratory of Technique and Equipment for Macromolecular Advanced Manufacturing South China University of TechnologyGuangzhou510641China

In fifth-generation wireless communication system(5G),more connections are built between metaheuristics and electromagnetic equipment *** this paper,we propose a self-adaptive grey wolf optimizer(SAGWO)combined with a novel optimization model of a 5G frequency selection surface(FSS)based on FSS unit *** includes three improvement strategies,improving the initial distribution,increasing the randomness,and enhancing the local search,to accelerate the convergence and effectively avoid local *** benchmark tests,the proposed optimizer performs better than the five other optimization algorithms:original grey wolf optimizer(GWO),genetic algorithm(GA),particle swarm optimizer(PSO),improved grey wolf optimizer(IGWO),and selective opposition based grey wolf optimization(SOGWO).Due to its global searchability,SAGWO is suitable for solving the optimization problem of a 5G FSS that has a large design *** combination of SAGWO and the new FSS optimization model can automatically obtain the shape of the FSS unit with electromagnetic interference shielding capability at the center operating *** verify the performance of the proposed method,a double-layer ring FSS is designed with the purpose of providing electromagnetic interference shielding features at28 *** results show that the optimized FSS has better electromagnetic interference shielding at the center frequency and has higher angular ***,a sample of the optimized FSS is fabricated and tested.

关键词： Grey wolf optimizer Fifth-generation wireless communication system(5G) Frequency selection surface Shape optimization

Secondary electron emission yield from vertical graphene nanosheets by helicon plasma deposition

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Chinese Physics B 2022年第2期31卷 613-617页

作者： Xue-Lian jin Pei-Yu Ji Lan-Jian Zhuge Xue-Mei Wu Cheng-gang jin School of Physical Science and Technology Soochow UniversitySuzhou 215006China Provincial Key Laboratory of Thin Films Soochow UniversitySuzhou 215006China Soochow University Analysis and Testing Center Suzhou 215006China Laboratory for Space Environment and Physical Sciences Harbin Institute of TechnologyHarbin 150001China

The secondary electron emission yields of materials depend on the geometries of their surface *** this paper,a method of depositing vertical graphene nanosheet(VGN)on the surface of the material is proposed,and the secondary electron emission(SEE)characteristics for the VGN structure are *** COMSOL simulation and the scanning electron microscope(SEM)image analysis are carried out to study the secondary electron yield(SEY).The effect of aspect ratio and packing density of VGN on SEY under normal incident condition are *** results show that the VGN structure has a good effect on suppressing SEE.

关键词： secondary electron emission secondary electron yield vertical graphene nanosheets scanning electron microscope

HETEROAROMATIC POLYMERS—HIGH TEMPERATURE POLYPYRROLONES DERIVED FROM 2,6-BIS(3',4'-DIAMINOPHENYL)-4-BIPHENYLPYRIDINE AND VARIOUS AROMATIC DIANHYDRIDES

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Chinese Journal of Polymer Science 2005年第5期23卷 521-529页

作者： Hai-xia Yang jin-gang Liu Xiao-juan Zhao Yan-feng Li Lin Fan Shi-yong Yang School of Chemistry and Chemical Engineering Lanzhou University Lanzhou 730000 China Laboratory of Advanced Polymer Materials Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China

A new type of aromatic tetraarnine containing biphenyl moiety in the side chain was synthesized via a modified Chichibabin＇s reaction. 3-Nitro-4-acetamidoacetophenone was reacted with 4-phenyl benzaldehyde in the presence of ammonium acetate to obtain 2,6-bis（3＇,4＇-diaminophenyl）-4-biphenyl pyridine （DPPA）. A series of polypyrrolones （PPys） were prepared using tetraamine and various aromatic dianhydrides via a two-step cyclization procedure. All the PPys show excellent high temperature stabilities with the initial decomposition temperatures of 530-549℃ and residual weight ratio of 49%-80% at 750℃ in nitrogen. The polymers exhibit no apparent glass transition temperatures （Tgs） except PPy-1 （Tg= 327℃）, which is derived from tetraamine DPPA and 2,2-bis[4-（3＇,4＇-dicarboxyphenoxy）-phenyl]propane dianhydride （BPADA）. In addition, the polymers have acceptable mechanical properties with the tensile strength of 65-94 MPa. The PPy films show excellent hydrolysis-resistance in alkaline aqueous medium and could maintain most of the properties even after boiling in 10% aqueous sodium hydroxide solution for a week.

关键词： Tetraamine Polypyrrolone Pyridine High temperature polymers Film Hydrolysis-resistance.

Effect of ion-beam assisted deposition on the film stresses of TiO_2 and SiO_2 and stress control

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Acta Mechanica Sinica 2012年第5期28卷 1382-1388页

作者： Yu-Qiong Li Hua-Qing Wang Wu-Yu Wang Zhi-Nong Yu He-Shan Liu gang jin National Microgravity Laboratory(NML) Institute of MechanicsChinese Academy of Sciences School of Optoelectronics Beijing Institute of Technology Optical Thin Film Center Daheng New Epoch Technology Inc. Beijing General Research Institute for Nonferrous Metals Division of Mineral Research and Material Energy

Based on Hartmann-Shack sensor technique, an online thin film stress measuring system was introduced to measure the film stresses of TiO2 and SiO2, and comparison was made between the film stresses prepared respectively by the conventional process and the ion-beam assisted deposition. The effect of ion-beam assisted deposition on the film stresses of TiO2 and SiO2 was investigated in details, and the stress control methodologies using on-line adjustment and film doping were put forward. The results show that the film stress value of TiO2 prepared by ion-beam assisted deposition is 40 MPa lower than that prepared by conventional process, and the stress of TiO2 film changes gradually from tensile stress into compressive stress with increasing ion energy; while the film stress of SiO2 is a tensile stress under ion-beam assisted deposition because of the ion-beam sputtering effect, and the film refractive index decreases with increasing ion energy. A dynamic film stress control can be achieved through in-situ adjustment of the processing parameters based on the online film stress measuring technique, and the intrinsic stress of film can be effectively changed through film doping.

关键词： Film stress Stress controlling Ion-beam as-sisted deposition Hartmann-Shack sensor