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Nontrivial homoclinic orbits for second-order singular and periodic Hamiltonian systems

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Chinese Science Bulletin 1999年第2期44卷 123-129页

作者： LI Chengyue , FAN Tianyou TONG MingshengResearch Center of Materials Science, Beijing Institute of Technology, Beijing 100081, china Department of Mathematics, {2. university for nationalities, Beijing 100081, china Computer Center, Beijing Institute of Technology, Beijing 100081, china Research Center of Materials Science Beijing Institute of Technology Beijing China Department of Mathematics Central University for Nationalities Beijing China Computer Center Beijing Institute of Technology Beijing China

The existence of nontrivial homoclinic orbits of periodic Hamiltonian systems: is proved, where q=（q1,q2.’',qn）, n>2. V（t, q）:R1×Rn\{e}→R1 is a potential With a singularity, i.e. -V（t, q）→+∞, as q→e. The m... 详细信息

The existence of nontrivial homoclinic orbits of periodic Hamiltonian systems: is proved, where q=（q1,q2./sub>,’',qn）, n>2. V（t, q）:R1×Rn\{e}→R1 is a potential With a singularity, i.e. -V（t, q）→+∞, as q→e. The main assumptions are Gordon-strong force condion and the uniqueness of a global maximum of V（t, q）.

关键词： Hamiltonian systems strong force condition homoclinic orbit.

Relationships between bacterial-algal proliferating and mass extinction in the Late Devonian Frasnian-Famennian transition:Enlightening from carbon isotopes and molecular fossils

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Science china Earth Sciences 2005年第10期48卷 1656-1665页

作者： GONG Yiming1,2. XU Ran1, TANG Zhongdao1, SI Yuanlan3 & LI Baohua4 1. Faculty of Earth Science and State Key Laboratory of Geological Processes and Mineral Resources, china university of Geosciences, Wuhan 430074, china 2. Institute of Resources & Environments, Henan Polytechnic university, Jiaozuo 454003, china 3. Department of Computer Science, South-central university for nationalities, Wuhan 430074, china 4. Laboratory of Marine Geology, Tongji university, Shanghai 2.0092. china Faculty of Earth Science and State Key Laboratory of Geological Processes and Mineral Resources china university of Geosciences Wuhan china Institute of Resources & Environments Henan Polytechnic university Jiaozuo china Department of Computer Science South-central university for {2. Wuhan china Laboratory of Marine Geology Tongji university Shanghai china

Studies show positive shifts of inorganic and organic carbon isotope values (δ 13Ccarb and δ 13Ckerogen) from +0.43 (‰ V-PDB) to +3.54 (‰ V-PDB) and from ?2..38 (‰ V-PDB) to ?2..14 (‰ V-PDB), respectively, B* (Ba* = Ba/ (Al2.3 X 15%)) values from 0.015 to 0.144, TOC values from 0.02. to 0.2.%, V/Cr values from 0.3 to 2.0, Sr/Ba values from 3.2. to 49.50 in the Late Devonian Frasnian Upper rhenana zone to the top linguiformis zone of the Yangdi sec-tion deposited in carbonate slope facies of Guilin, Guangxi, South china, which indicates that biomass, productivity, organic carbon burial and salinity increase and that oxygenation near the boundary between sediments and waters decreases from the Late Devonian Frasnian Upper rhenana zone to the top linguiformis zone. Abundance of molecular fossils increases and normal alkanes, isoprenoid hydrocarbon, terpanes and steranes are dominated from the Late Devonian Frasnian to the bottom of Famennian, which shows that the predecessors of molecular fossils of the Frasnian-Famennian (F-F) transition are dominated by marine phytoplankton, zooplankton and benthic bacteria with no photosynthesis. Therefore, it is considered that the F-F transitional mass extinction with a multistage, selection and global synchronizing was caused by bacte-rial-algal proliferating, continuing deterioration of the shallow marine ecoenvironment of the mid-dle-lower latitudes. A simple cause and effect chain can be expressed as: appearance of seed plants and multi-storied forests → enhanced chemical and biochemical weathering and pe-dogenesis → wide development of soils → increasing riverine nutrient fluxes in epicontinental sea → from superoligotrophic to eutrophic in epicontinental sea → proliferating of marine phyto-plankton and zooplankton → frequent red tide and anoxia → mass extinction of shallow marine organisms in the middle-lower latitudes. It is worth notice that the factor drawdown of atmos-pheric Pco2. climatic cooling and sea level falling c

关键词： mass extinction, bacteria-algae, carbon isotopes, molecular fossils, biodiversity, Late Devonian, Guangxi, South china.

INFINITELY MANY SOLUTIONS FOR A SINGULAR ELLIPTIC EQUATION INVOLVING CRITICAL SOBOLEV-HARDY EXPONENTS IN R^N

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Acta Mathematica Scientia 2010年第3期30卷 830-840页

作者：贺小明邹文明 school of Sciences Central University for Nationalities Department of Mathematical Sciences Tsinghua University

In this article, we study the existence of multiple solutions for the singular semilinear elliptic equation involving critical Sobolev-Hardy exponents -△μ-μ｜x｜^2.-μ=α｜x｜^s^-｜μ｜^2.（s）-2.＋βα（x）｜u｜^r-2.,x∈R^n. By means of the concentration-compactness principle and minimax methods, we obtain infinitely many solutions which tend to zero for suitable positive parameters α,β.

关键词： Singular elliptic equation Multiple solutions Critical Sobolev-Hardy exponent Minimax method

Analysis theory of random energy of train derailment in wind

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Science china(Physics,Mechanics & Astronomy) 2010年第4期53卷 751-757页

作者： CHEN RuiLin 1,2.3 , ZENG QingYuan 3 , HUANG YunQing 1 , XIANG Jun 3 , WEN Ying 3 , GUO XiaoGang 2., YIN ChangJun 2., DONG Hui 2.& ZHAO Gang 4 1 Hunan Key Laboratory for Computation and Simulation in Science and Engineering, Xiangtan university, Xiangtan 411105, china 2.{2. of Civil Engineering & Mechanics, Xiangtan university, Xiangtan 411105, china 3 {2. of Civil Architecture, central South university, Changsha 410075, china 4 AMEC, Toronto M5A5G7, Canada 1. Hunan Key Laboratory for Computation and Simulation in Science and Engineering Xiangtan University Xiangtan 411105 China2. School of Civil Engineering & Mechanics Xiangtan University Xiangtan 411105 China3. School of Civil Architecture Central South University Changsha 410075 China4. AMEC Toronto M5A5G7 Canada

Based on the analysis theory of random energy of train derailment, an analysis theory of random energy of train derailment in wind is suggested. Two methods are proposed -the time domain method and the frequency domain method of analysis theory of random energy of train derailment in wind. The curves of σ pw -v under various wind speeds are obtained through the computation. The original curve of σ p -v is expanded, which turns the analysis theory of random energy of train derailment into the all-weather theory. Train derailment condition has been established under wind action. The first and second criterions of train derailment have been proposed in light of wind action. The analysis of train derailment cases at home or abroad is made, in- cluding the first analysis of Xinjiang train derailment case encountered 13-level of gale, which explained the inevitability of train derailment. The analysis theory of random energy of train derailment in wind shows its validity and accuracy. The input energy σ pw of the transverse vibration of train-track(bridge)-wind system is linked to train speed. With the establishment of the analysis theory of random energy of train derailment in wind, It is likely to initiate an all-weather speed limit map for a train or any high-speed train.

关键词： train derailment analysis theory of random energy of train derailment analysis theory of random energy of train de- railment in wind train derailment condition in wind the criterion of train derailment in wind train derailment case

Electronic structure and magnetic properties of SmCo7-xTix

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Science china(Physics,Mechanics & Astronomy) 2006年第1期49卷 38-45页

作者： ZHANG Changwen1, LI Hua1, DONG Jianmin1, GUO Yongquan2.& LI Wei2.1. school of Physics and Microelectronics, Shandong university, Jinan 2.0100, {2. 2. Institute of Functional Materials, central Iron and Steel Research Institute, Beijing 100081, {2. 1. school of Physics and Microelectronics Shandong University Jinan 250100 China 2. Institute of Functional Materials Central Iron and Steel Research Institute Beijing 100081 China

Electronic structure of SmCo7-xTix alloy has been studied by means of the spin-polarized MS-Xα method. It is shown that a few of electrons are transferred to Sm(5d) orbital due to orbital hybridization between Sm and Co atoms. The exchange interaction between 5d-3d electrons is stronger, which is the main reason resulting in the long-range ferromagnetic order between Co and Sm atoms. The Curie temperature of SmCo7-xTix is generally lower than that of pure Co metal, which may be explained by the weaker aver- age of coupling strength between Co sites due to some negative exchange couplings occurring mainly at 2. site. The calculated results for the Sm5Co2.Ti6 cluster may lead to a better understanding of why SmCo7-xTix is stable phase. Since the negative interaction of 2. sites weakens and the bonding at EF strengthens with increasing Ti concentration, which result in the decrease in the free energy of the alloy, the stable ferromagnetic order forms inside SmCo7-xTix. Considering the localization of 4f states and 5d moment arising from the orbital hybridization, the calculated moment is 9.47μB per formula unit that is in agreement with experiments.

关键词： electronic structure, spin polarization, atomic magnetic moment, exchange coupling, Curie temperature.

Electronic structure and magnetic properties of metastable SmCo_(7) compound

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Science china(Physics,Mechanics & Astronomy) 2005年第3期48卷 325-335页

作者： ZHANG Changwen 1 , LI Hua 1 , DONG Jianmin 1 , WANG Yongjuan 1 , PAN Fengchun 1 , ZHANG Jian 1 , GUO Yongquan 2.& LI Wei 2.1. school of Physics and Microelectronics, Shandong university, Jinan 2.0100, {2. 2. Institute of Functional Materials, central Iron and Steel Research Institute, Beijing 100081, {2. 1. school of Physics and Microelectronics Shandong University 250100 Jinan China 2. Institute of Functional Materials Central Iron and Steel Research Institutes 100081 Beijing China

The electronic density of states, spin-splittings and atomic magnetic moments of SmCo 7 compound have been studied using spin-polarized MS-Xα method. The results show that a few of electrons are transferred to Sm(5d 0 ) orbital because of orbital hybridization between Sm and Co atoms in the compound. The exchange interactions between 3d and 5d electrons lead to the magnetic coupling between Sm and Co, and therefore, result in the long-range ferromagnetic order inside the SmCo 7 compound. There are negative exchange couplings occurring at some levels, which weakens the strength of average coupling around Co lattice. So, the Curie temperature and Co-moment of SmCo 7 decrease distinctly compared with pure Co. Compared with SmCo 5 compound, the disordered substitution of Co-Co “dumbbell-atom” pairs for Sm changes the local environment of Co lattice, which makes the 2. site bear negative magnetic moment. The strength of hybridization near Fermi level weakens and the free energy of the compound increases obviously. Thus, SmCo 7 is a metastable compound at room temperature. Considering the localization of 4f electrons and a few of 5d electrons arising from the orbital hybridization, the magnetic moment of Sm atom will be 1.61μ B in SmCo 7 compound, which is in agreement with the experimental values of Sm 3+ ion- moment and Sm atom-moment in metals.

关键词： electronic structure, spin polarization, atomic magnetic moment, exchange coupling, Curie temperature.

Dynamic scheduling model of computing resource based on MAS cooperation mechanism

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Science in china(Series F) 2009年第8期52卷 1302-1320页

作者： JIANG WeiJin1,2. ZHANG LianMei3 & WANG Pu4 1 school of Computer and Electronic Engineering, Hunan university of Commerce, Changsha 4102.5, {2. 2.school of Information Engineering, Xiangtan university, Xiangtan 411000, {2. 3 Electrical Engineering College, Wuhan university, Wuhan 430072. {2. 4 school of Commerce, central South university, Changsha 410083, {2. 1. school of Computer and Electronic Engineering Hunan University of Commerce Changsha 410205 China 2. school of Information Engineering Xiangtan University Xiangtan 411000 China 3. Electrical Engineering College Wuhan University Wuhan 430072 China 4. school of Commerce Central South University Changsha 410083 China

Allocation of grid resources aims at improving resource utility and grid application performance. Currently, the algorithms proposed for this purpose do not fit well the autonomic, dynamic, distributive and heterogeneous features of the grid environment. According to MAS （multi-agent system） cooperation mechanism and market bidding game rules, a model of allocating allocation of grid resources based on market economy is introduced to reveal the relationship between supply and demand. This model can make good use of the studying and negotiating ability of consumers＇ agent and takes full consideration of the consumer＇s behavior, thus rendering the application and allocation of resource of the consumers rational and valid. In the meantime, the utility function of consumer is given; the existence and the uniqueness of Nash equilibrium point in the resource allocation game and the Nash equilibrium solution are discussed. A dynamic game algorithm of allocating grid resources is designed. Experimental results demonstrate that this algorithm diminishes effectively the unnecessary latency, improves significantly the smoothness of response time, the ratio of throughput and resource utility, thus rendering the supply and demand of the whole grid resource reasonable and the overall grid load balanceable.

关键词： multi-agent system (MAS) resource scheduling model evolutionary game cooperation mechanism utility function

Effect of Nd_2.e_(14)B/α-Fe Nanocomposite Permanent Magnets with a Combined Co and Nb Additions

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Journal of Wuhan university of Technology(Materials Science) 2009年第5期24卷 725-727页

作者：马瑞 school of Materials Science and Metallurgy Engineering Guizhou University

Influence of Co＋Nb on the Nd8Fe82.o3Nb1B6 nanocomposite magnets was investigated by adding Co element combined with Nb element. Results show that the high temperature stability of two phases is increased. Adding Co＋Nb could improve the glass forming ability of the alloy, reduce the size of grains, increase the exchange coupling ability of two phases, and obviously increase the magnetic properties of the alloy. The optimal magnetic properties are Br=1.14 T, Hcj=32. kA/m, （BH）max=109.3 kJ/m^3

关键词： nanocomposite permanent magnets glass forming ability exchange coupling ability magnetic properties

Polycomb group proteins and their roles in carcinogenesis

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Chinese Science Bulletin 2012年第18期57卷 2259-2264页

作者： XIAO LanBo 1,2.3,TAO YongGuang 1,2.3,LI LiLi 1,2.3,4 & CAO Ya 1,2.31 Key Laboratory of Carcinogenesis of Ministry of Health,Xiangya school of Medicine,central South {2.,Changsha 410078,china 2.Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education,Xiangya school of Medicine,central South {2.,Changsha 410078,china 3 Cancer Research Institute,Xiangya school of Medicine,central South {2.,Changsha 410078,china 4 Cancer Epigenetics Laboratory,State Key Laboratory in Oncology in South china,Chinese {2. of Hong Kong,Hong Kong 999077,china Key Laboratory of Carcinogenesis of Ministry of Health Xiangya School of Medicine Central South University Key Laboratory of Carcinogenesis and Cancer Invasion of Ministry of Education Xiangya School of Medicine Central South University Cancer Resea

In the cell nucleus,DNA is wound around histone proteins,which are then packed together to form *** can be chemically tagged by methyl and acetyl *** group (PcG) proteins attach methyl groups to genes,which block their *** is similar to the attachment of methyl groups to gene promoters by DNA methyltransferases (DNMTs).This action is directly linked with tumor initiation and metastasis via the promotion of anti-senescence and anti-apoptosis pathways,and by facilitating epithelial mesenchymal transition (EMT).Cell fate transcriptional factors (CFTFs) and long non-coding RNAs (long ncRNAs) recruit PcG proteins to the promoters of tumor suppressor genes,resulting in epigenetic gene silencing by influencing chromatin structure and DNA ***,PcG proteins are potential diagnostic markers and targets for new chemoprevention and therapeutic strategies.

关键词：组蛋白 DNA甲基转移酶基因启动子癌变非编码RNA PEG 凋亡途径抑癌基因