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Peculiar dynamical properties of plutonium hydrides

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Progress in Natural Science:Materials International 2006年第3期16卷 248-254页

作者： MENG Daqiao, ZHU Zhenghe, LUO Deli and JIANG Gang (Institute of Atomic and Molecular Physics, Sichuan University, chengdu 610065, china.national Key laboratory of Surface Physics and Chemistry, Mianyang 621907, china. [a]Institute of Atomic and Molecular Physics Sichuan University Chengdu China [b]national Key laboratory of Surface Physics and Chemistry Mianyang China

In the present work, the structure and spectra of PuH and PuH2 are defined by B3LYP/SDD method, from which the analytic potential energy function of PuH2 is derived. The analysis of quasi-classical molecular reaction dynamics is performed to study the state-state process of Pu(7Fg) + H2(X1∑g+). It is found that the reaction Pu(7Fg)+H2(X1∑g+)→PuH2(X7B1) has no threshold. The simultaneous hydrogenation process of plutonium with the main product of PuH2 is theoretically proved for the first time.

关键词： hydrogenation reaction of plutonium molecular dynamics density functional theory.

Kinetic energy and charge state effects in the X-ray emission of Mo surface induced by Xe^(q+)(q=25,29) ions

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Science china.Physics,Mechanics & Astronomy) 2008年第9期51卷 1240-1244页

作者： CUI Ying1,YANG ShengSheng2,YANG ZhiHu3,XU JinZhang1,ZHANG HongQiang1,XU Xu1,SHAO JianXiong1,LIU ZhaoYuan1,XIAO GuoQing3,ZHANG XiaoAn4,ZHAO YongTao3,ZHANG YanPing3 & CHEN XiMeng1 1 Department of modern Physics,Lanzhou University,Lanzhou 730000,china.2 national Key laboratory of Vacuum & Cryogenics Technology and Physics,Lanzhou 730000,china.3 Institute of modern Physics,Chinese Academy of Sciences,Lanzhou 730000,china.4 Normal College of Xianyang,Xianyang 713000,china Department of modern Physics Lanzhou University Lanzhou 730000 China national Key laboratory of Vacuum & Cryogenics Technology and Physics Lanzhou 730000 China Institute of modern Physics Chinese Academy of Sciences Lanzhou 730000 China Normal College of Xianyang Xianyang 713000 China

L-shell X-ray spectra of Mo surface induced by Xe25+ and Xe29+ were measured. The X-ray intensity was obtained in the kinetic energy range of the incident ions from 350 to 600 keV. The relationship of X-ray intensity ... 详细信息

关键词： X-ray surface kinetic energy and charge state effect Xeq+

Cardiac nonrigid motion analysis from image sequences

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Progress in Natural Science:Materials International 2006年第10期16卷 1115-1118页

作者： LIU Huafeng (State Key laboratory of modern Optical Instrumentation, Zhejiang University, Hangzhou 310027, china. [a]State Key laboratory of modern Optical Instrumentation Zhhejiang University Hangzhou China

Noninvasive estimation of the soft tissue kinematics properties from medical image sequences has many important clinical and physiological implications, such as the diagnosis of heart diseases and the understanding of cardiac mechanics. In this paper, we present a biomechanics based strategy, framed as a priori constraints for the ill-posed motion recovery problems, to realize estimation of the cardiac motion and deformation parameters. By constructing the heart dynamics system equations from biomechanics principles, we use the finite element method to generate smooth estimates of heart kinematics throughout the cardiac cycle. We present the application of the strategy to the estimation of displacements and strains from in vivo left ventricular magnetic resonance image sequence.

关键词： cardiac motion and deformation continnum mechanics model finite element method.

Influence of Alumina Addition on the Optical Property of Zirconia/Alumina Composite Dental Ceramics

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Journal of Wuhan University of Technology(Materials Science) 2011年第4期26卷 690-695页

作者：蒋丽李伟 State Key laboratory of Oral Diseases Sichuan University

The influence of various alumina additions on the optical property of zirconia/alumina composite ceramics was investigated. The relative sintered densities, transmittances, color and the microstructure of the composite ceramics were studied. The experimental results showed that the relative sintered densities and transmittances decreased with alumina addition. The lightness increased obviously but the chroma change was small. Pure zirconia nanopowders sintered densely could obtain the relatively high transmittance, while the transmittance and the lightness of slight addition changed significantly. The zirconia/alumina composite ceramics with alumina addition less than 7.5wt% could achieve the relatively stable and reliable optical properties.

关键词： alumina addition zirconia/alumina ceramics transmittance color optical properties

ELASTIC-PLASTIC FINITE ELEMENT ANALYSIS OF THREE-DIMENSIONAL CONTACT-IMPACT AT RAIL JOINT

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Chinese Journal of Mechanical Engineering 2003年第4期16卷 411-416页

作者： Wen ZefengJin XuesongZhang Weihuanational Traction Power laboratory,Southwest Jiaotong University,chengdu 610031, china Southwest Jiaotong University National Traction Power Laboratory Chengdu 610031

Using the finite element code ANSYS/LS-DYNA, a dynamic finite element modelwith an elastic-linear-kinematic-hardening plastic material is established to analyzeelastic-plastic stresses in the railhead in the impact process of wheel and rail occurring at thegap of rail joint. The model is based on the discrete elastic support condition of the rails, whichis suitable for the actual situation of wheel/track rolling contact. In the analysis the influencesof axle load, yield stress and tangent modulus of rail material on the stresses and strains areinvestigated in detail. The distribution of stresses and strains in the jointed railhead are *** is found that the axle load, yield stress and tangent modulus of rail material greatly affect thestresses and strains in the railhead during impacting. The study provides a reliable method anduseful datum for the further research on fatigue and wear of railhead and improving the rail jointmode.

关键词： Wheel/rail Rail joint Elastic-plastic Contact-impact Finite elementmethod

Gelation behavior of Antheraea pernyi silk fibroin

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Science china.Chemistry 2010年第3期53卷 535-541页

作者： YAN ShuQin,ZHAO ChunXia,WU XiuFang,ZHANG Qiang & LI MingZhong national Engineering laboratory for modern Silk College of Textile and Clothing Engineering,Soochow University,Suzhou 215123,china 1. national Engineering laboratory for modern Silk College of Textile and Clothing Engineering Soochow University Suzhou 215123 China

The sol-gel transition behavior of Antherae pernyi silk fibroin(Ap-SF) has not been systematically *** this work,the influence of environmental temperature,pH,the concentration of Ap-SF,K+ and Ca2+ on the gelation time,and the structural changes of Ap-SF in sol-gel transformation were *** results indicated that the gelation time of the Ap-SF aqueous solution decreased with the increase of the Ap-SF concentration and environmental *** sol-gel transformation of Ap-SF was much more rapid than that of Bombyx mori silk fibroin under the same *** Ap-SF was sensitive to changes in the concentration of Ca2+ and K+.Upon gelation,the random coil structure of the Ap-SF was significantly transformed into the β-sheet structure.

关键词： Antheraea pernyi silk fibroin gelation sol-gel transition

RECENT PROGRESS ON CONTROLLABILITY/OB SERVABILITY FOR SYSTEMS GOVERNED BY PARTIAL DIFFERENTIAL EQUATIONS

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Journal of Systems Science & Complexity 2010年第3期23卷 527-545页

作者： Hongheng LI Qi LU Xu ZHANG School of Mathematics Sichuan University Chengdu 610064 China Key laboratory of Systems and Control Academy of Mathematics and Systems Sciences Chinese Academy of Sciences Beijing 100190 China

The main purpose of this paper is to overview some recent methods and results on controllability/observability problems for systems governed by partial differential equations. First, the authors review the theory for linear partial differential equations, including the iteration method for the null controllability of the time-invariant heat equation and the Rellich-type multiplier method for the exact controllability of the time-invariant wave equation, and especially a unified controllability/observability theory for parabolic and hyperbolic equations based on a global Carleman estimate. Then, the authors present sharp global controllability results for both semi-linear parabolic and hyperbolic equations, based on linearization approach, sharp observability estimates for the corresponding linearized systems and the fixed point argument. Finally, the authors survey the local null controllability result for a class of quasilinear parabolic equations based on the global Carleman estimate, and the local exact controllability result for general hyperbolic equations based on a new unbounded perturbation techniaue.

关键词： Controllability hyperbolic equations observability parabolic equations.

Failure Mechanisms of Post-Earthquake Bedrock Landslides in Response to Rainfall Infiltration

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Journal of Mountain Science 2011年第1期8卷 96-102页

作者： WU Yong HE Siming LUO Yu LI Xinpo Key laboratory of Mountain Hazards and Earth Surface Process Chinese Aeademy of Sciences Chengdu 610041 China Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China

Among the triggering factors of postearthquake bedrock landslides, rainfall plays an important role. However, with slope variation, the mechanism of its effects on the failure of rock landslides is not dear. Here, from the viewpoint of fracture mechanics, and based on post-earthquake conditions, the mechanisms of crack propagation, water infiltration and development of the sliding surface were investigated. Then, according to the upper boundary theorem, the effects of water infiltrated into fractures on the stability of rock slopes were analyzed quantitatively. Finally, an example is presented to verify the theory. The results show that the propagation and coalescence of cracks and the lubrication of incipient sliding surfaces are the main causes of the failure of post-earthquake rock landslides in response to rainfall.

关键词： Post-earthquake Fracture infiltration Fracture mechanics Propagation and coalescence Upper boundary theorem Energy theory Rock landslide

Multi-level decollement zones and detachment deformation of Longmenshan thrust belt,Sichuan Basin,southwest china

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Science china.Earth Sciences 2008年第S2期51卷 32-43页

作者： TANG LiangJie1,2,3,YANG KeMing4,JIN WenZheng1,2,3,L ZhiZhou4 & YU YiXin1,2,3 1 State Key laboratory of Petroleum Resource and Prospecting,china.University of Petroleum,Beijing 102249,china.2 Key laboratory for Hydrocarbon Accumulation Mechanism,china.University of Petroleum,Ministry of Education,Beijing 102249,china.3 Basin and Reservoir Research Center,china.University of Petroleum,Beijing 102249,china.4 Southwest Division Company,SINOPEC,chengdu 610081,china 1. State Key laboratory of Petroleum Resource and Prospecting China University of Petroleum Beijing 102249 China 2. Key laboratory for Hydrocarbon Accumulation Mechanism China University of Petroleum Ministry of Education Beijing 102249 China 3. Basin and Reservoir Research Center China University of Petroleum Beijing 102249 China 4. Southwest Division Company SINOPEC Chengdu 610081 China

As is well known that many decollement layers were developed in the Longmenshan thrust belt,Si-chuan Basin,china. Through field investigation,explanation of seismic profiles and analysis of the balanced sections,we can divide the decollement zones into 3 categories: (1) the deep level decolle-ment zones,including the crust-mantle decollement layer,intracrustal decollement layer,and presinian basal decollement layer. The main structural styles of their deformation are the crust-mantle decoup-ling detachment deformation,the basal ductile shear deformation,etc.; (2) the middle level decollement zones,including the Cambrian-Ordovician decollement layer,the Silurian decollement layer,etc.,the main structural styles of their deformation are the isopachous fold,the angular fold,the saddle struc-ture,and the combination styles of them; and (3) the shallow level decollement zones,including the Xujiahe Formation decollement layer of Upper Triassic and the Jurassic decollement layers,the main structural styles of their deformation are the thrust-nappe tectonic,the pop-up,the triangle zone ,the duplex,etc. Multi-level decollement zones not only made the Longmenshan thrust belt develop many different deformation styles from deep place to shallow place,but also made some local areas have the superimposition of the tectonic deformation apparently. This study indicates that the multi-level de-collement zones have a very important effect on the shaping and evolution of the Longmenshan thrust belt.

关键词： decollement layer structural styles multi-level decollement zones Longmenshan thrust belt