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Evolution of Bright Screening-photovoltaic Spatial Optical Solitons

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Chinese Journal of Lasers 2001年第5期10卷 28-33页

作者： LIU Jinsong (State key laboratory of Laser Technology, Huazhong University of Science and Technology, Wuhan 430074, china) 华中科技大学激光技术国家重点实验室湖北武汉

A numerical analysis of the dynamical evolution of bright screening photovoltaic (SP) spatial solitons in biased photovoltaic photorefractive materials in the case of neglecting the material loss and the diffusion is presented. When an incident optical beam is a bright SP soliton, the beam propagates along a linear path with its shape kept unchanged. When the incident optical beam is slightly different from a bright SP soliton, the beam reshapes itself and tries to evolve into a bright SP soliton after a short distance. However, when the incident optical beam is significantly different from a SP bright soliton, the beam cannot evolve into a stable bright SP soliton, and tends to experience periodic compression and expansion. For a low intensity input beam, the wave experiences a periodic process of compression first and then expansion during the initial part of the cycle. For a high intensity input beam, however, the wave will initially diffract and then experiences compression during the cycle.

关键词： nonlinear optics spatial optical solitons photorefractive effects

Estimation of Cellobiohydrolase I Activity by Numerical Differentiation of Dynamic Ultraviolet Spectroscopy

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Acta Biochimica et Biophysica Sinica 2006年第6期38卷 372-378页

作者： Bin WU Yue ZHAO Pei-Ji GAO The State key laboratory of Microbial Technology,Shandong University,Jinan 250100,china The State key laboratory of Microbial Technology Shandong UniversityJinan 250100 China

1,4-β-D-glucan cellobiohydrolase I （CBH I）,p-nitrophenyl β-D-cellobioside,p-nitrophenol andcellobiose show distinct ultraviolet spectra,allowing the design of an assay to track the dynamic process ofp-nitrophenyl β-D-cellobioside hydrolysis by CBH *** on the linear relationship between p-nitrophenolformation in the hydrolysate and its first derivative absorption Curve of AUC340400nm（area under the curve）,a new sensitive assay for the determination of CBH I activity was *** dynamic parameters ofcatalysis reaction,such as Vm and kcat,can all be derived from this *** influence of β-glucosidase andendoglucanase in crude enzyme sample on the assay was discussed in *** approach is useful foraccurate determination of the activity of CBHs.

关键词： cellobiohydrolase dynamic spectrum area under the curve(AUC)

Ultralight X-type lattice sandwich structure (Ⅱ):Micromechanics modeling and finite element analysis

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Science china(Technological Sciences) 2009年第9期52卷 2670-2680页

作者： ZHANG QianCheng1,CHEN AiPing 2,CHEN ChangQing2,3 & LU TianJian2 1 State key laboratory for Mechanical Behavior of Materials,School of Material Science and Engineering,Xi’an Jiaotong University,Xi’an 710049,china 2 MOE key laboratory for Strength and Vibration,School of Aerospace,Xi’an Jiaotong University,Xi’an 710049,china 3 Department of Engineering Mechanics,AML,Tsinghua University,Beijing 100084,china State key laboratory for Mechanical Behavior of Materials School of Material Science and Engineering Xi’an Jiaotong University Xi’an China MOE key laboratory for Strength and Vibration School of Aerospace Xi’an Jiaotong University Xi’an China Department of Engineering Mechanics AML Tsinghua University Beijing China

The methods of homogenization and finite elements are employed to predict the effective elastic constants and stress-strain responses of a new type of lattice structure,the X-structure proposed by the authors in a companion paper. It is shown that in most cases the predictions by the equivalent homogenization theory agree well with the experimental and 3-dimensional finite element calculated results. The theoretical and numerical study supports the argument that the X-structure is superior to the pyramid lattice structure in terms of mechanical strength.

关键词： sandwich panel lattice structure equivalent homogenization finite element model

NONCONFORMING FINITE ELEMENT APPROXIMATIONS TO THE UNILATERAL PROBLEM

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Journal of Computational Mathematics 1999年第1期17卷 15-24页

作者： Lie-heng Wang(State key laboratory of Scientific and Engeneering Computing, ICMSEC,Chinese Academy of Sciences, Beijing 100080, china) Chinese Acad Sci State Key Lab Sci & Engn Comp ICMSEC Beijing 100080 Peoples R China

The nonconforming finite element (two Crouzeix-Raviart linear elements and Wilson element) approximations to the unilateral problem are considered. The error bounds for these elements are obtained in the appropriate a... 详细信息

关键词： unilateral problem nonconforming finite element

Interannual variation of annual precipitation and urban effect on precipitation in the Beijing region

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Progress in Natural Science:Materials International 2007年第9期17卷 1042-1050页

作者： Yu Shuqiu(State key laboratory on Severe Weather,Chinese Academy of Meteorological Sciences,Beijing 100081,china) State key laboratory on Severe Weather Chinese Academy of Meteorological Sciences Beijing 100081， China

The large scale character of the interannual variation of precipitation and the urban effect on local annual precipitation anomaly are investigated in this paper based on the 1960-2000 annual precipitation observations at 20 stations in the Beijing *** results show that:the annual precipitation in the Beijing region possesses the large scale variation character with the linear trend of-1.197/10 yr,which corresponds to a total reduction of 27.82 mm in annual precipitation in the 41 years;the local annual precipitation anomalies(percent of the normal 1960-2000)show a positive center near the urban area,*** precipitation island(UPI),whose intensity increases with the linear trend of 0.6621%/10 yr,opposite to the interannual trend of large scale precipitation over the Beijing region;changes in the UPI are also associated with the intensity of synoptic processes of precipitation,and when the synoptic processes are strong(wet years),the intensity of UPI strengthens,while the synoptic processes are weak(dry years),and the UPI disappears in the Beijing region.

关键词： urban precipitation island effect interannual climate variation precipitation Beijing atmospheric science

Main Controls on Hydrocarbon Accumulation in the Paleozoic in Central Saudi Arabia

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Petroleum Science 2007年第2期4卷 10-17页

作者： Bai Guoping (key laboratory for Hydrocarbon Accumulation under Ministry of Education, china University of Petroleum, Beijing 102249, china) key laboratory for Hydrocarbon Accumulation under Ministry of Education China University of PetroleumBeijing102249China

Sandi Arabia is renown for its rich oil and gas Mesozoic. However, the discovery of Paleozoic fields in resources with the bulk of the reserves reservo/red in the the late 1980s has encouraged further exploration in the Paleozoic. This paper reviews the salient features of the Paleozoic petroleum geology in central Saudi Arabia and discusses the main factors controlling hydrocarbon accumulation in the Paleozoic. The Lower Silurian Qusaiba hot shale is the principal source rock for the hydrocarbons discovered in the Ordovician to Permian reservoirs. Of them, the Permo- Carboniferous Unayzah and Upper Ordovician Sarah Formations have the best exploration potential. The key factors controlling hydrocarbon accumulation in the Unayzah Formation are migration pathways and reservoir petrophysics. The key factors controlling hydrocarbon accumulation in the Sarah Formation are reservoir petrophysics and the development of structural traps.

关键词： Paleozoic oil and gas accumulations central Saudi Arabia main controls Qusaiba hot shale Unayzah play,Sarah play

Cloning and sequencing of nifBHDKENX genes of Paenibacillus massiliensis T7 and its nif promoter analysis

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Science china(Life Sciences) 2006年第2期49卷 115-122页

作者： ZHAO Hongxin1,2,3, XIE Baoen2 & CHEN Sanfeng1,2 1. State key laboratory for Agrobiotechnology and Biological School, china Agricultural University, Beijing 100094, china 2. key laboratory for Agro-Microbial Resource and Application of Agriculture Ministry, china Agricultural University, Beijing 100094, china 3. Chemical and Biological School, ShenYang Normal University, Shenyang 110034, china 1. State key laboratory for Agrobiotechnology and Biological School China Agricultural University Beijing 100094 China 2. key laboratory for Agro-Microbial Resource and Application of Agriculture Ministry China Agricultural University Beijing 100094 China 3. Chemical and Biological School ShenYang Normal University Shenyang 110034 China

A 324 bp of nifH fragment was PCR amplified from Paenibacillus massiliensis T7 using the universal degenerate primers. The PCR-amplified nifH fragment was labeled with DIG; then used as a probe in Southern blot analysis. Southern blot result showed that there were two positive signals, indicating that there might be two copies of nifH in P. massiliensis T7. A total of 10254 bp DNA sequence containing purD; nifBHDKENX was obtained by five rounds of inverse-PCR amplification. The predicted proteins of nifBHDKENX had high homology with those from other nitrogen-fixing bacteria. Only one putative σ[54]-dependent promoter sequence was detected upstream of the nifB gene; nifBHDKENX were likely to be organized in one operon. Assays of β-galactosidase activity of P. massiliensis T7PB carrying a nifB-lacZ fusion under different concentrations of NH4 [+]; O2 showed that the expression of nifB-lacZ was strongly inhibited by O2.

关键词： Paenibacillus massiliensis T7, nifBHDKENX, nifB-lacZ, inverse-PCR.

DISTRIBUTED FINITE-TIME χ-CONSENSUS ALGORITHMS FOR MULTI-AGENT SYSTEMS WITH VARIABLE COUPLING TOPOLOGY

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Journal of Systems Science & Complexity 2010年第2期23卷 209-218页

作者： Xiaoli WANG·Yiguang HONG key laboratory of Systems and Control,Chinese Academy of Sciences,Beijing 100190,china. key laboratory of Systems and Control Chinese Academy of Sciences

This paper considers finite-time χ-consensus problem for a multi-agent system with firstorderindividual dynamics and switching interaction *** distributed finite-time consensusrules are constructed for multi-agent dynamics in a unified way with the help of Lyapunovfunction and graph theory as well as ***-invariant non-smooth forms of finite-timeneighbor-based controllers are proposed and a numerical example is shown for illustration.

关键词： χ-consensus distributed control multi-agent networks non-smoothness switching graphs.

Study on H atoms diffusion and adsorption properties of MgH_2-V systems

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Science china(Technological Sciences) 2008年第7期51卷 979-988页

作者： ZHOU DianWu1,2, LIU JinShui3 & PENG Ping3 1 State key laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha 410082, china 2 College of Mechanical and Automatic Engineering, Hunan University, Changsha 410082, china 3 College of Materials Science and Engineering, Hunan University, Changsha 410082, china 1. State key laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan University Changsha 410082 China 2. College of Mechanical and Automatic Engineering Hunan University Changsha 410082 China 3. College of Materials Science and Engineering Hunan University Changsha 410082 China

Based on experimental results that VH0.81/MgH2 interface was found during the process of mechanically milling MgH2+5at.%V nanocomposite, H atoms diffusion and adsorption properties of MgH2-V systems have been investigated by using a first-principles plane-wave pseudopotential method based on the density functional theory. The results are as follows. When VH/MgH2 interface is formed due to V alloying MgH2 phase, the vacancy formed by H atoms near VH phase region is more stable than that without V alloying, while vacancy near MgH2 phase region is less stable than that without V alloying. During the process of H atoms diffusion after V alloying, the max migration barrier energy of H atoms in MgH2-V systems is reduced compared with that of MgH2 phase, which means that H atoms diffuse easily. When H diffuses into VH from MgH2 across VH/MgH2 interface, among three substitutions such as the replacement of H for V vacancy, or interstitial site or V atoms, the replacement of H for V vacancy has the strongest diffusion ability, next interstitial site, and finally V atoms site. As far as H adsorbed on different surfaces of VH phase is concerned, physical adsorption is carried out more easily than chemical adsorption, and the behavior of H atoms adsorbed on the surface near VH phase region can be found more easily than that near MgH2 phase region.

关键词： plane-wave pseudopotential theory magnesium hydride diffusion adsorption