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Effect of rock mass structure and block size on the slope stability——Physical modeling and discrete element simulation

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Science china(Technological sciences) 2005年第z1期48卷 1-17页

作者： LI Shihai1, LIAN Zhenzhong1,2 & J. G. Wang3 1. Institute of Mechanics, chinese academy of sciences, Beijing 100080, china 2. graduate school, chinese academy of sciences, Beijing 100060, china 3. Tropical Marine Science Institute, National University of Singapore, Singapore 119260 chinese Acad Sci Inst Mech Beijing 100080 Peoples R China chinese Acad Sci Grad Sch Beijing 100060 Peoples R China Natl Univ Singapore Trop Marine Sci Inst Singapore 119260 Singapore

This paper studies the stability of jointed rock slopes by using our improved three-dimensional discrete element methods (DEM) and physical modeling. Results show that the DEM can simulate all failure modes of rock slopes with different joint configurations. The stress in each rock block is not homogeneous and blocks rotate in failure development. Failure modes depend on the configuration of joints. Toppling failure is observed for the slope with straight joints and sliding failure is observed for the slope with staged joints. The DEM results are also compared with those of limit equilibrium method (LEM). Without considering the joints in rock masses, the LEM predicts much higher factor of safety than physical modeling and DEM. The failure mode and factor of safety predicted by the DEM are in good agreement with laboratory tests for any jointed rock slope.

关键词： rock masses, slope stability, DEM simulation, block size effect, joints configuration effect, limit equilibrium method.

Antisense expression of a rice cellular apoptosis susceptibility gene (OsCAS} alters the height of transgenic rice

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Progress in Natural Science:Materials International 2007年第1期17卷 39-43页

作者： XU Chunxiao and HE Chaozu ( National Key Laboratory of Plant Genomics, Institute of Microbiology, chinese academy of sciences, Beijing 100080, china graduate University of chinese academy of sciences, Beijing 100039, china Shenzhen Laboratory of Superhybrid Rice Research, graduate school at Shenzhen, Tsinghua University, Shenzhen 518055, china) [a]National Key Laboratory of Plant Genomics Institute of Microbiology Chinese Academy of Sciences Beijing China [b]graduate University of chinese academy of sciences Beijing China

Cellular apoptosis susceptibility (CAS) gene plays important roles in mitosis, development and export of importin a from the nucleus, but its function in plant is unknown. In this study, a rice CAS ortholog (OsCAS), which encodes a predicted protein of 983 amino acids with 62% similarity to human CAS, was identified. DNA gel blot analysis revealed a single copy of OsCAS in the rice genome. A 973 bp fragment at the 3' end of OsCAS cDNA was cloned from rice cDNA library and transferred into rice in the antisense direction under the control of CaMV 35S promoter via Agrobacterium-mediated transformation method, 105 transgenic lines were obtained. Expression of OsCAS was suppressed in the antisense transgenic lines as revealed by semi-quantitative RT-PCR. The antisense transgenic lines showed dwarf phenotypes. The results indicated that OsCAS was involved in culm development of rice.

关键词： antisense dwarf ortholog OsCAS rice.

Effect of the Small Reaustenized Grains on the Mechanical Properties of a HSLA Steel

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Journal of Iron and Steel Research International 2011年第S1期18卷 312-315页

作者： ZHAO Lian-yu 1,2,WEI Yan 1,SHAN Yi-yin 1,YANG Ke 1 (1.Institute of Metal Research,chinese academy of sciences,Shenyang 110016,Liaoning,china 2.graduate school of chinese academy of sciences,Beijing 100049,china) chinese Acad Sci Inst Met Res Shenyang 110016 Liaoning Peoples R China chinese Acad Sci Grad Sch Beijing 100049 Peoples R China

Grain refinement improves not only strength but also *** reaustenized grains were discovered to form along the grain boundaries and lath boundaries in an as rolled high-strength low-alloy (HSLA) steel when heated to double phase *** number and size of the small reaustenized grains were revealed to depend mainly on temperature in the range of 700 to 760℃.These small reaustenized grains were deduced to form by consuming *** mechanical property tests showed that they resulted in slight changes to tensile ***,the sample heated at 740℃ produced a peak Charpy V-notch (CVN) impact energy of 248J when tested at-30℃.Fractography showed that the facture surface of the 740℃ heated impact sample exhibited the smallest brittle zone away from the notch root and a large dimple zone lay ahead of the notch tip,which demonstrated the highest toughness.

关键词： high-strength low-alloy steel reaustenization grain refinement tensile property

An efficient chiral synthesis of (R)-N-[3-acetyl-4-(2-hydroxy-3-isopropylamino-propoxy)phenyl]-butanamide with high enantioselectivity

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Science china Chemistry 2009年第8期52卷 1216-1219页

作者： WANG NaiXing1,2 & TANG XinLiang1,3 1 Technical Institute of Physics and Chemistry,chinese academy of sciences,Beijing 100080,china 2 College of Chemistry and Chemical Engineering,graduate University of chinese academy of sciences,Beijing 100049,china 3 school of Chemical Engineering and Environment,Beijing Institute of Technology,Beijing 100081,china 1. Technical Institute of Physics and Chemistry Chinese Academy of Sciences Beijing 100080 China 2. College of Chemistry and Chemical Engineering Graduate University of Chinese Academy of Sciences Beijing 100049 China 3. school of Chemical Engineering and Environment Beijing Institute of Technology Beijing 100081 China

R-Enantiomer of the β-receptor antagonist N-[3-acetyl-4-(2-hydroxy-3-isopropylamino-propoxy)phenyl] butanamide with high enantioselectivity was synthesized from cheap starting materials and enantiopure chiral reagent through an efficient,convenient and practical synthetic *** product was detected by 1H NMR,13C NMR,and MS,and the enatiomeric excess was determined by chiral HPLC analysis using a chiracel AD-H column.

关键词： chiral synthesis enantioselectivity enatiomeric excess chiral HPLC analysis

An improved imaging algorithm for fixed-receiver bistatic SAR

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Science china(Information sciences) 2010年第7期53卷 1461-1469页

作者： GENG XuPu1,2,3, HU YingHui1,2, YAN HongHui2 & WANG YanFei2 1graduate school of the chinese academy of sciences, Beijing 100039, china 2Institute of Electronics, chinese academy of sciences, Beijing 100190, china 3Beijing Institute of Environment Features, Beijing 100854, china 1. graduate school of the chinese academy of sciences Beijing 100039 China2. Institute of Electronics Chinese Academy of Sciences Beijing 100190 China3. Beijing Institute of Environment Features Beijing 100854 China

Based on the signal model of fixed-receiver bistatic SAR, this paper analyzes the characteristics of azimuth-variant, which includes variation of range migration curve and variation of Doppler rate caused by different azimuth position of targets. Then, an extended nonlinear chirp scaling (NLCS) algorithm is proposed, with its flowchart and phase compensation functions being provided. Simulation results show that the algorithm is available for the characteristics of azimuth-variant of fixed-receiver bistatic SAR, and good focused radar images could be acquired.

关键词： synthetic aperture radar (SAR) bistatic SAR fixed-receiver characteristics of azimuth-variant range cell migration correction (RCMC)

Nitrogen isotopic composition of plant-soil in the Loess Plateau and its responding to environmental change

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chinese Science Bulletin 2009年第2期54卷 272-279页

作者： LIU WeiGuo1,2 & WANG Zheng1,3 1 State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, chinese academy of sciences, Xi’an 710075, china 2 Xi’an Jiaotong University, school of Human Settlement and Civil Engineering, Xi’an 710049, china 3 graduate University of chinese academy of sciences, Beijing 100049, china chinese Acad Sci Inst Earth Environm State Key Lab Loess and Quaternary Geol Xian 710075 Peoples R China.

The nitrogen isotope of soil is of emerging significance as an indicator of climatic change and biogeochemical cycle of nitrogen in nature systems. In this paper, the nitrogen content and isotopic composition of modern ecosystems from arid and semiarid Loess Plateau in northwestern china, including plant roots and surface soil, were determined to investigate trends in δ15N variation of plant roots and soil along a precipitation and temperature gradient in northwestern china under the East Asian Monsoon climate condition. The δ15N values of surface soil from the study area vary from ?1.2‰ to 5.8‰, but from -5.1‰ to 1.9‰ in the plant roots. Our results indicate that (1) although the isotopic compositions of both plant roots and surface soil change with a similar trend along the climate gradient, the apparent nitrogen difference between plant roots and soil existed, with -δ15N values ranging from 0.3‰ to 7.2‰ with average of 4.1‰; and (2) mean annual precipitation (MAP) is the dominant factor for isotopic composition of plant-soil nitrogen in the Loess Plateau, and the δ15N values are less correlated with MAT; we suggest that nitrogen isotopic composition of soil is a potential tracer for environmental changes.

关键词：氮同位素物理性质化学性质环境论

IMPLICITIZATION USING UNIVARIATE RESULTANTS

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Journal of Systems Science & Complexity 2010年第4期23卷 804-814页

作者： Liyong SHEN Chunming YUAN school of Mathematical sciences Graduate University Chinese Academy of Sciences Beijing 100049 China Key Laboratory of Mathematics Mechanization Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

Among several implicitization methods, the method based on resultant computation is a simple and direct one, but it often brings extraneous factors which are difficult to remove. This paper studies a class of rational space curves and rational surfaces by implicitization with univaxiate resultant computations. This method is more efficient than the other algorithms in finding implicit equations for this class of rational curves and surfaces.

关键词： Implicitization rational space curves rational surfaces resultants.

Synthesis of well-defined functional PE graft copoly-mers via ATRP process

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Science Bulletin 2005年第10期50卷 1048-1051页

作者： CAO Chengang1, 2, DONG Jinyong1 & HU Youliang1 1. CAS Key Laboratory of Engineering Plastics, Joint Laboratory of Polymer Science and Materials, Institute of Chemistry, chinese academy of sciences, Beijing 100080, china 2. graduate school, chinese academy of sciences, Beijing 100039, china CAS Key Laboratory of Engineering Plastics Joint Laboratory of Polymer Science and Materials Institute of Chemistry Chinese Academy of Sciences Beijing 100080 China graduate school Chinese Academy of Sciences Beijing 100039 China

In summary, we have demonstrated a convenient yet highly efficient method forthe preparation of PE-based graft copolymers via ATRP.. By introducing a small amount of styrenegroups into PE chains via the selective copolymerization of ethylene with 1,4-divinylbenzenecatalyzed by Et(Ind)_2ZrCl_2/MAO, the multifunctional ATRP initiator of1-chloroethylbenzene-containing PE was readily achieved by a quantitative hydrochlorination reactionand was shown to be very effective for the initiation of graft polymerization of MMA and styrene toprepare structurally well-defined PE-based graft copolymers.

关键词： ATRP Synthesis of well-defined functional PE graft copoly-mers via ATRP process PE well

DNA barcoding:species delimitation in tree peonies

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Science china(Life sciences) 2009年第6期52卷 568-578页

作者： ZHANG JinMei1,2,WANG JianXiu1,2,XIA Tao1,2 & ZHOU ShiLiang1 1State Key Laboratory of Systematic and Evolutionary Botany,Institute of Botany,the chinese academy of sciences,Beijing 100093,china 2graduate school of the chinese academy of sciences,Beijing 100039,china 1. State Key Laboratory of Systematic and Evolutionary Botany Institute of Botany the Chinese Academy of Sciences Beijing 100093 China 2. graduate school of the chinese academy of sciences Beijing 100039 China

Delimitations of species are crucial for correct and precise identification of *** "spe-cies" is more a subjective than an objective concept in taxonomic practice due to difficulties in revealing patterns of infra-or inter-specific *** phylogenetic studies at the population level solve this problem and lay a sound foundation for DNA *** this paper we exemplify the necessity of adopting a phylogenetic concept of species in DNA barcoding for tree peonies(Paeonia ***).We used 40 samples representing all known populations of rare and endangered species and several populations of widely distributed tree *** currently recognized species and major variants have been included in this *** chloroplast gene fragments,***,rps16-trnQ,trnL-F and trnS-G(a total of 5040 characters,96 variable and 69 parsimony-informative characters) and one variable and single-copy nuclear GPAT gene fragment(2093?2197 bp,279 variable and 148 parsi-mony-informative characters) were used to construct phylogenetic relationships among the *** evolutionary lineages revealed by the nuclear gene and the chloroplast genes are inconsistent with the current circumscriptions of ***,***,***,and *** based on *** inconsistencies come from(1) significant chloroplast gene divergence but little nuclear GPAT gene divergence among population systems of *** + ***,and(2) well-diverged nuclear GPAT gene but little chloroplast gene divergence between *** and *** incongruence of the phylogenies based on the chloroplast genes and the nuclear GPAT gene is probably due to the chloro-plast capture event in evolutionary history,as no reproductive barriers exist to prevent inter-specific *** also evaluated the suitability of these genes for use as DNA barcodes for tree *** variability of chloroplast genes among well-defined species or population systems of a specie

关键词： DNA barcoding evolution Paeonia phylogeny species concept