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Influence of valence electron structures of phase and biphase interfaces of sulfides on hot brittleness in steel

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science China(Technological sciences) 2004年第4期47卷 488-504页

作者： LIU Yan1.3, LIU Zhilin1. ZHANG Chengwei1.2 & ZHOU {1.chun1.1. Liaoning Institute of Technology, Jinzhou 1.1.01. China 2. China National Oil and Gas Exploration and Development Corporation, beijing 1.001., China 3. college of science, Northeastern University, Shengyang 1.0006, China 1. Liaoning Institute of Technology 121001 Jinzhou China 2. college of {1. Northeastern University 110006 Shengyang China 3. China National Oil and Gas Exploration and Development Corporation 100011 Beijing China

This paper calculates the electron structures of phase of FeS, MnS and their biphase interface electron structures with austenite in steel. The precipitation and the transformation of FeS and MnS are investigated through studying the valence electron pair numbers on the strongest bond n A with the structure formation factor S. The continuity of electron density and its relation with stress are explored in the biphase interfaces with the electron density difference απ Using n A, S, απ we explain the reason why FeS can bring about hot brittleness in steel and the physical mechanism why MnS may eliminate or inhibit hot brittleness, based on which satisfying results are obtained by calculating several rare-earth sulfides.

关键词： valence electron structure, sulfide, hot brittleness, and rare earth.

Comparison of the virulence plasmid genomes of two strains of Shigella which lost the ability to bind Congo red

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science China({1. sciences) 2006年第2期49卷 141-148页

作者： XIONG Zhaohui1. TANG Xudong1.2, YANG Fan1. ZHANG Xiaobing1. YANG Jian1. CHEN Lihong1. NIE Huan1. YAN Yongliang1. JIANG Yan1. WANG Jing1. XUE {1.1. XU Xingye1. ZHU Yafang1. DONG Jie1. AN Lizhe2, WANG Xunling2 & JIN Qi1.1. State Key Laboratory for Molecular Virology and Genetic Engineering, beijing 1.0052, China 2. School of life science, Lanzhou University, Lanzhou, 743000) 1. State Key Laboratory for Molecular Virology and Genetic Engineering Beijing 100052 China 2. School of life {1. Lanzhou University Lanzhou 743000 China

We determined; analyzed the Shigella flexneri serotype 5 (pSF5); S. dysenteriae serotype 1.(pSD1. virulence plasmid genomes. The total length of pSF5 is 1.651. bp, including 1.5 open reading frames (ORFs). Of these ORFs, 1.3 were identified; 32 of those had no significant homology to proteins with known functions. The length of pSD1.is 1.2545 bp, including 224 ORFs, of which we identified 1.1. The remaining 43 ORFs were not significantly homologous to proteins with known functions. The insertion sequence (IS) elements are 53787 bp in pSF5,; 4961. bp in pSD1. which represents 39.4%; 27.1. of the genome, respectively. There are 22 IS element types in pSF5; pSD1. among which we report ISEc8; ISSbo6 for the first time in the Shigella virulence plasmid. Compared to pCP301. there are a large number of deleted genes; gene inversions in both pSF5; pSD1. The ipa-mxi-spa locus in pSF5 is completely absent,; the genes related to the O-antigen biosynthesis are partially missing. In contrast, the above genes in pSD1.are integral, with the exception of virF. The whole genome analysis of the two plasmids shows that the loss of genes related to gene invasion or regulation also obliterates the ability of pPF5; pSD1.to bind Congo red (Crb). Whether these genes determine the Crb function requires continued investigation.

关键词： Shigella flexneir serotype 5, Shigella dysenteriae serotype 1. virulence plasmid, Congo red, genome comparison.

Utilization of a spiropyran derivative in a polymeric film optode for selective fluorescent sensing of zinc ion

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science China Chemistry 2006年第3期49卷 246-255页

作者： ZHANG ying1. SHAO Na1. YANG Ronghua1. LI Ke’an1. LIU Feng1. CHAN Winghong2 & MO Tian2 1. {1. of Chemistry and Molecular Engineering, peking University, beijing 1.0871. China 2. Department of Chemistry, Hong Kong Baptist University, Hong Kong, China 1. college of Chemistry and Molecular Engineering Peking University Beijing 100871 China 2. Department of Chemistry Hong Kong Baptist University Hong Kong China

A new spiropyran derivative was synthesized and first utilized in a polymericfilm-based optical sensor for zinc ion. Spiropyrans, combining the characteristics of metal bindingand signal transduction, show potential function in the design of optical chemical sensors(optodes) toward metal ions. When embedded in a plasticized poly (vinyl chloride) (PVC) membrane,the newly synthesized spiropyran derivative 1.exhibits obvious fluorescence enhancement at 630 nm inthe presence of zinc ion in aqueous solution. With the optimum condition described, the optodemembrane responds to zinc ion over a dynamic range of 4.94x1.^(-7) to 4.1.x1.^(-4)mol·L^(-1., witha detection limit of 1.51.1.^(-7) mol·L^(-1.. The membrane not only displays excellentphotostability, reproducibility and reversibility, but also exhibits high selectivity toward zincion over transition metal ions including Hg^(2+), Cd^(2+), Pb^(2+), Cu^(2+), Fe^(3+) and commoncationic ions presented in the physiological fluids.

关键词： spiropyran, sensor, PVC membrane, zinc ion, fluorescent spectroscopy.

Existence of solutions for the dynamic equation of ferrimagnets

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Progress in Natural science:Materials International 2007年第11期17卷 1279-1283页

作者： Zeng Ming1. Guo Boling2 and Cheng Caozong1.1. {1. of Applied sciences, beijing University of Technology, beijing 1.0022, China 2. Center for Nonlinear Studies, Institute of Applied Physics and Computational Mathematics, beijing 1.0088, China) college of Applied {1.s Beijing University of Technology Beijing 100022 China Center for Nonlinear Studies Institute of Applied Physics and Computational Mathematics Beijing 100088 China

Ferrimagnet is a kind of basic and important multi-sublattice magnet material. It has attracted more and more attention of physicists and mathematicians. Many results of solitons and numerical computations on this topic have appeared. In this article, the dynamic equation for an isotropic ferrimagnet with two non-equivalent sublattices is studied, existence of weak solutions in multi dimension case is proved through the penalized method, the uniqueness and smoothness of the solution in one dimension case are also obtained by the relation between this equation and hyperbolic equation.

关键词： ferrimagnet weak solutions penalized method finite difference method

Effect and mechanism of stresses on rock permeability at different scales

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science China Earth sciences 2006年第7期49卷 714-723页

作者： YIN Shangxian1.& WANG Shangxu2 1. Safety Engineering college, North China Institute of {1. and Technology, Yanjiao, beijing 1.1.01. China 2. Key Laboratory of Geophysics Exploration, China University of Petroleum, beijing 1.0083, China 1. Safety Engineering college North China Institute of Science and Technology Yanjiao Beijing 101601 China 2. Key Laboratory of Geophysics Exploration China University of Petroleum Beijing 100083 China

The effect of geo-stress fields on macroscopic hydro-geological conditions or micro-cosmic permeability of water-bearing media should follow some laws or principles. Cases study and tests show that: (1. At macro-geologic large scale, deformed and crashed rocks which were induced by geo-stress fields changing provided space for groundwater storage and flow. Groundwater adjusts water-bearing space and dilatants fractures by flowing and press transferring. Coupling of liquid and solid can be implemented for rocks and groundwater. Although tectonic fields witness several times of change and build-up in geological time, stress fields forming regional tectonic framework are coherent with seepage fields, orientation of the maximum horizontal stress demonstrates main seepage direc-tions. (2) At macro-geologic middle scale, zones of stresses changing sharply, quite low stresses, stress or shear concentration can be used to show locations and types of main fractures, zones of geo-stresses changing equably can be acted as normal base media zones of tri-porosity media. (3) At micro-geologic small scale, tri-porosity media include fractured rocks, porous rocks and capillary rocks. Investigations indicate that porosity or permeability is functions of effective stresses, and po-rosity or permeability changing rules of porous rocks with variation of effective stresses can be de-scribed as the index model, the model of power exponent functions is suitable for those of fractured rocks, the model of the second power parabola for capillary rocks. The porosity and permeability loss in fractured rocks, which are greater than that in porous rocks, are shown by calculation of effective compressive coefficient and closing pressure in cracks. The calculations can also explain the mecha-nism why porosity changes are always larger than permeability changes. It is proved by the thick wall cylinder theory that the second power parabola relation between porosity or permeability loss and effective

关键词： geo-stress fields, seepage fields, tri-porosity media, effective stresses, permeability, porosity,scale.

Epigenetic reprogramming in mammalian nuclear transfer

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Chinese science Bulletin 2004年第8期49卷 766-771页

作者： LI Shijie1.2, DU Weihua1.& LI Ning1.1. State Key Laboratory for Agrobiotechnology, China Agricultural University, beijing 1.0094, China 2. Department of Biochemistry and Molecular Biology, {1. of life science, Hebei Agriculture University, Baoding 071.01. China Correspondence should be addressed to Li Ning (e-mail: ninglbau@ ***) State Key Laboratory for Agrobiotechnology China Agricultural University Beijing 100094 China Department of Biochemistry and Molecular Biology College of Life Science Hebei Agriculture University Baoding 071001 China

Somatic cloning has been succeeded in some species, but the cloning efficiency is very low, which limits the application of the technique in many areas of research and biotechnology. The cloning of mammals by somatic cell nuclear transfer (NT) requires epigenetic reprogramming of the differentiated state of donor cell to a totipotent, embry-onic ground state. Accumulating evidence indicates that in-complete or inappropriate epigenetic reprogramming of do-nor nuclei is likely to be the primary cause of failures in nu-clear transfer. This review summarizes the roles of various epigenetic mechanisms, including DNA methylation, histone acetylation, imprinting, X-chromosome inactivation, te-lomere maintenance and expressions of development-related genes on somatic nuclear transfer.

关键词：哺乳动物细胞核液迁移后成程序改编 DNA甲基化作用组蛋白乙酰化作用 X-染色体活化端粒印痕基因表达克隆

Inducing effect of Pb(Zr_(0.4)Ti_(0.6))O_3 thin film derived by different processes in BiFeO_3/Pb(Zr_(0.4)Ti_(0.6))O_3 multilayer capacitor at room temperature

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science China(Technological sciences) 2009年第1期52卷 10-14页

作者： XIE Dan1. ZANG YongYuan1. LUO YaFeng1. REN Tianling1. LIU LiTian1.& DANG ZhiMin2 1.Institute of Microelectronics, Tsinghua University, {1. 1.0084, China 2 college of Material science and Engineering, {1. University of Chemical Technology, {1. 1.0029, China Institute of Microelectronics Tsinghua University Beijing 100084 China college of Material {1. and Engineering Beijing University of Chemical Technology Beijing 100029 China

BiFeO3/PZT multilayer capacitor was prepared on Pt(1.0)/Ti/SiO2/Si(1.0) substrate. PZT buffer layer was derived by MOCVD method (label: PZT1. and sputtering method (label: PZT2) respectively. XRD analysis indicated that high (1.0) orientation of BFO in the BFO/PZT1.structure was achieved. SEM analysis indicated a better microstructure in the BFO/PZT1.structure compared with BFO/PZT2. The remnant polarization of the BFO/PZT1.was 82.5 μC/cm2 at an applied voltage of 8 V, compared with that of 25.2 μC/cm2 in the BFO/PZT2 structure. The BFO/PZT1.multilayer exhibited little polarization fatigue (1.5%) upon 1.1.1. switching cycles, at an applied voltage of 4 V. The leakage current density was about 2×1.?7 A/cm2 at an applied voltage 4 V, in the BFO/PZT1.capacitor. All the results indicated that PZT can act as an inducing layer to the BFO and the MOCVD derived PZT has more inducing effect to the BFO thin film at room temperature.

关键词： BFO PZT MOCVD properties FeRAM

Analysis of a 2D “liquid”plasma lattice

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science China(Physics,Mechanics & Astronomy) 2004年第1期47卷 129-136页

作者： HUA Jianjun1. LIU Yanhong1.& ZHANG Zhihe2 1. Institute of Physics, Chinese Academy of sciences, {1. 1.0080, China 2. college of Biomedical Engineering, Capital University of Medical sciences, {1. 1.0054, China Correspondence should be addressed to Hua Jianjun (email: jj_hua@***) Received September 20, 2003 1. Institute of Physics Chinese Academy of Sciences 100080 Beijing China 2. college of Biomedical Engineering Capital University of Medical Sciences 10054 Beijing China

To study the structural and dynamical properties of a 2D dusty plasma lattice, a set of experiments were performed in an environment of radio frequency discharge. Based on the results of one of the experiments, pair correlation function, bond-orientational correlation function and mean square displacement of such a system were computed and analyzed. The bond-orientational correlation function is found to fit in with the law of e?r , and the mean square displacement is found to increase monotonously with time, both of which, together with the pair correlation function, indicate that the two-dimensional dusty plasma lattice formed in the experiment stayed in a “liquid” state.

关键词： plasma lattice, pair correlation function, bond-orientational correlation function, mean square displacement.

An integrated decision method for prediction of tropical cyclone movement by using genetic algorithm

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science China Earth sciences 2005年第3期48卷 429-440页

作者： YANG Yuanqin1.& WANG Jizhi2 1. National Meteorological Center, beijing 1.0081.China 2. Chinese Academy of Meteorological {1.s, beijing 1.0081. China 1. National Meteorological Center 100081 Beijing China 2. Chinese Academy of Meteorological sciences 100081 Beijing China

In this study an integrated decision method for the multi-prediction results of tropical cyclone movements by using genetic algorithm (GA) has been adopted. A genetic learning artifi- cial neural network (GLANN) as a learning mechanism for track prediction was developed through training with the huge samples of typhoon tracks from 1.84 to 2002. The prediction of typhoon motion is to consider how to suit the dynamic change of environment, where typhoon passed through. The neural network structure is described by GA. A fitness function for choice of GA is given to approach the maximum of fitness (the minimum of the errors). Parallel comparing analyses for prediction abilities of unusual typhoon tracks in recent years by GLANN with multi-forecast methods were conducted. More types of cases were employed in the comparing analyses, which consist of the typhoon, Winnie, No.1., in 1.97, characterized by a long life over the ocean and in the mainland with severe effect on China, the 1. unusual typhoon tracks in the 1.90s, the tracks with landfall and affected action in 1.98 and the typhoons born in the Northwestern Pacific and the South China Sea in 2000, including the 24—48 h forecast, etc. The results indicated that for prediction ability of typhoon tracks, specially for unusual typhoons, GA decision-making developed in this study is superior to the others.

关键词： genetic algorithm, integrated decision, prediction of tropical cyclone.