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REACTION MECHANISM OF BENZOPHENONE-PHOTOINITIATED CROSSLINKING OF POLYETHYLENE

Chinese Journal of Polymer Science 2002年第4期20卷 291-307页

作者： Bao-jun Qu State Key Laboratory of Fire Science and department of Polymer Science and engineering university of Science and Technology of china Hefei 230026 china Univ Sci & Technol china State Key Lab Fire Sci Hefei 230026 Peoples R China Univ Sci & Technol china Dept Polymer Sci & Engn Hefei 230026 Peoples R China

The radical intermediates, the crosslink microstructures, and the reaction mechanism of benzophenone (BP)-photoinitiated crosslinking of low-density polyethylene (LDPE) and model compounds (MD) have been reviewed in detail. The spin-trapping electron spin resonance (ESR) spectra obtained from the LDPE/BP systems with spin-trap agents show that two kinds of polymer radical intermediates are mainly formed: tertiary carbon and secondary carbon radicals. The spin-trapping ESR studies of MD/BP systems give further evidence that photocrosslinking reactions of PE predominantly take place a sites of tertiary carbon, secondary carbon, and especially allylic carbon when available. The high resolution C-13-NMR spectra obtained from LDPE and MD systems show that the crosslink microstructures have H- and Y-type links and that their concentrations are of the same order. The fluorescence, ESR, C-13 and H-1-NMR spectra from the PE and MD systems demonstrate that the main photoreduction product of BP (PPB) is benzpinacol formed by the recombination of two diphenylhydroxymethyl (K-.) radical intermediates. Two new PPB products: an isomer of benzpinacol with quinoid structure, 1-phenylhydroxymethylene-4-diphenylhydroxymethyl-2,5-cyclobexadiene and three kinds of alpha-alkyl-benzhydrols have been detected and identified. These results provide new experimental evidence for elucidating the reaction mechanism in the BP-photoinitiated crosslinking of polyethylene.

关键词： photocrosslinking mechanism polymer radical intermediates crosslink microstructures photolytic products of benzophenone polyethylene model compound

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Micromechanical analysis of interaction energy for SMA reinforced composite

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Science china(Technological Sciences) 2009年第3期52卷 610-616页

作者： ZHU YuPing1,2, DUI GuanSuo1 & DUO Liu3 1 Institute of Mechanics, Beijing Jiaotong university, Beijing 100044, china 2 department of engineering Mechanics, Jiangsu university, Zhenjiang 212013, china 3 State Key Lab of Crystal Materials, Shandong university, Jinan 250100, china Institute of Mechanics Beijing Jiaotong University Beijing 100044 China department of engineering Mechanics Jiangsu University Jiangsu Zhenjiang 212013 China State Key Lab of Crystal Materials Shandong University Jinan 250100 China

The energy of the interaction between the matrix and the inclusions in shape memory alloy (SMA) re- inforced composite is one of the most important and complicated parts in thermodynamic constitutive theory. In this paper, the interaction energy is derived based on the classical theory of micromechanics and the thermodynamic theory. The SMA composite is treated as three phases, namely the austenitic phase, the martensite phase and the matrix phase. The interaction among the three phases is analyzed in a way close to the fact. The present expression is used to calculate the interaction energy of a typical SMA composite with attentions paid to understand of the effects of the matrix material, the fiber ge- ometry, and the fiber/matrix volume ratio. It is shown that the method developed in this paper is credible compared with the references. Some useful conclusions are obtained.

关键词： shape memory alloy interaction energy SMA composite micromechanics thermodynamics

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Finite-dimensional Lie superalgebras of Cartan type over fields of prime characteristic

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Chinese Science Bulletin 1997年第9期42卷 720-724页

作者： ZHANG Yongzhengdepartment of Mathematics, northeast Normal university, Changchun, 130024, china department of Mathematics Northeast Normal University Changchun China

IN this note the infinite-dimensional Lie superalgebras of Cartan type X(m,n)(X=W,S,H or K)over field F of prime characteristic are *** the second class of finite-dimensional Lie superalgebras of Cartan type over F is... 详细信息

关键词： exterior algebra Lie superalgebra filtration.

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NUMERICAL PREDICTION OF PARTICLE MIXING BEHAVIOR IN A BUBBLING FLUIDIZED BED

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Journal of Hydrodynamics 2007年第3期19卷 335-341页

作者： WU Chun-liang ZHAN Jie-min engineering College Guangdong Ocean University Zhanjiang 524088 China department of Applied Mechanics and engineering Zhongshan University Guangzhou 510275 China

In this article the hard-sphere Discrete Particle Model （DPM） is used to study the mixing behavior of particles in the 2-D fluidized bed. Different flow patterns in the bed for two kinds of inlet configurations, namely free bubbling and jet bubbling mode, are captured by the numerical model, under specific superficial gas velocities. To examine the degree of particle mixing, the Fan index is applied. The numerical results show that the rate of particle mixing is larger in the jet bubbling than that in the free bubbling mode. The gross circulations of particles in the jet bubbling bed give a higher degree of mixing because of the involvement of a greater number of particles.

关键词： Discrete Particle Model (DPM) particle mixing fluidized bed

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Noether-type theory for discrete mechanico-electrical dynamical systems with nonregular lattices

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Science china(Physics,Mechanics & Astronomy) 2010年第9期53卷 1687-1698页

作者： FU JingLi1,CHEN LiQun2 & CHEN BenYong3 1 Institute of Mathematical Physics,Zhejiang Sci-Tech university,Hangzhou 310018,china 2 department of Mechanics,Shanghai university,Shanghai 200072,china 3 Faculty of Mechanical-engineering & Automation,Zhejiang Sci-Tech university,Hangzhou 310018,china 1. Institute of Mathematical Physics Zhejiang Sci-Tech University Hangzhou 310018 China2. Department of Mechanics Shanghai University Shanghai 200072 China3. Faculty of Mechanical-Engineering & Automation Zhejiang Sci-Tech University Hangzhou 310018 China

We investigate Noether symmetries and conservation laws of the discrete mechanico-electrical systems with nonregular *** operators of discrete transformation and discrete differentiation to the right and left are introduced for the *** on the invariance of discrete Hamilton action on nonregular lattices of the systems with the dissipation forces under the infinitesimal transformations with respect to the time,generalized coordinates and generalized charge quantities,we work out the discrete analog of the generalized variational *** this formula we derive the discrete analog of generalized Noether-type identity,and then we present the generalized quasi-extremal equations and properties of these equations for the *** also obtain the discrete analog of Noether-type conserved laws and the discrete analog of generalized Noether theorems for the *** we use an example to illustrate these results.

关键词： Noether symmetry variational formula quasi-extremal equation conservation law discrete mechanico-electrical dynamical system

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Quantifying soil erosion with GIS-based RUSLE under different forest management options in Jianchang Forest Farm

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中国科学：技术科学英文版 2006年第z1期49卷 160-166页

作者： ZHANG Hengming, WANG Qingli, DAI Limin, Guofan Shao, TANG Una, WANG Shunzhong & GU Huiyan Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, china Graduate university of Chinese Academy of Sciences, Beijing 100101, china department of Forestry and Natural Resources, Purdue university, Lafayette IN47901, USA northeast Forestry university, harbin 150040, china Institute of Applied Ecology Chinese Academy of Sciences Shenyang 110016 China Graduate university of Chinese Academy of Sciences Beijing 100101 China department of Forestry Natural Resources Purdue University Lafayette IN 47901 USA northeast Forestry university Harbin 150040 China

Quantitatively estimating soil erosion with an integration of geographic information system (GIS) and the revised universal soil loss equation (RUSLE) under four different exposed soil proportion scenarios caused by forest management practices was studied at Jianchang Forest Farm. The GIS provided means of input data generation required by RUSLE model and allowed a spatial assessment of the erosion hazard over the study area. Four exposed soil proportion scenarios of 5%, 10%, 20% and 30% were tested with the GIS-based RUSLE model to evaluate soil erosion hazard. The predicted soil erosion potentials were classified into five categories in order to provide valuable aids for management planning.

关键词： geographic information system, RUSLE, soil erosion, forest management.

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Effect of Carbon on Dynamic Recrystallization Behavior of Vanadium Microalloy Steels

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Journal of Iron and Steel Research International 2011年第S1期18卷 129-134页

作者： LIU Guo-quan 1,2,ZHAO Hai-tao 1,WU Jin-bin 1,WANG Cheng-yang 1,XU Lei 1,3 (1.School of Materials Science and engineering,university of Science and Technology Beijing,Beijing 100083,china 2.State Key Laboratory for Advanced Metals and Materials,university of Science and Technology Beijing,Beijing 100083,china 3.department of Materials Science and engineering,Tsinghua university,Beijing 100084,china) Univ Sci & Technol Beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China Univ Sci & Technol Beijing State Key Lab Adv Met & Mat Beijing 100083 Peoples R China Tsinghua Univ Dept Mat Sci & Engn Beijing 100084 Peoples R China

The hot working behavior especially dynamic recrystallization of low-carbon and medium-carbon vanadium microalloy steels has been studied by performing isothermally compression tests and Avrami *** Avrami plots of the two experiment steels have been constructed based on flow stress curves following a new approach (Jonas,et *** Mater.,2009,57(2):2748-2756;Wu et al,Acta ***.,2010,46(7):838-843).It is experimentally found that the carbon effect on dynamic recrystallization is opposite to each other in lower and higher strain ranges:Carbon causes a softening effect at low strain rates (0.01,0.1,and 1.0 s-1),and a hardening effect at high strain rates (10.0 and 30.0 s-1).Correspondingly,carbon promotes the dynamic recrystallization at low strain rates and retards the dynamic recrystallization at high strain rates in the experimental *** phenomenon is then tentatively explained based on the possible mechanisms of dynamic process at different strain rates.

关键词： vanadium microalloy steels hot working dynamic recrystallization carbon strain rate Avrami modeling

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Effect of Fe metal on the growth of silicon oxide nanowires

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International Journal of Minerals,Metallurgy and Materials 2009年第3期16卷 317-321页

作者： Wei-long Liu1), Shu-huei Hsieh1), Ching He Chen2), and Wen-jauh Chen3) 1) department of Materials Science and engineering, Formosa university, Yunlin 632, china Taipei 2) department of Materials engineering, Pingtung university of Science and Technology, Pingtung 912, china Taipei 3) Graduate School of Materials Science, Yunlin university of Science and Technology, Yunlin 632, china Taipei [a]department of Materials Science and engineering Formosa University Yunlin 632 China Taipei [b]Department of Materials Engineering Pingtung University of Science and Technology Pingtung 912 China Taipei [c]Graduate School of Materials Science Yunlin University of Science and Technology Yunlin 632 China Taipei

Silicon oxide (SiOx) nanowires are generally grown on Si substrate under the catalysis of Au in N2 atmosphere at elevated temperatures. Because the price of Au metal is quite high, Fe metal is then used to replace a part of Au for catalyzing the growth of SiOx nanowires. The results show that the Fe film can be used as the diffusion barrier of Au. SiOx nanowires are grown on Au/Fe/Si substrate at 1030°C. Under the catalysis of Fe/Au, the efficiency for the growth of SiOx nanowires is promoted.

关键词： silicon oxide nanowires Au catalyst Fe substitution Si substrate

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On the TOPS mode spaceborne SAR

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Science china(Information Sciences) 2010年第2期53卷 367-378页

作者： BAI Xia 1 , SUN JinPing 2 , HONG Wen 3 & MAO ShiYi 2 1 department of Electronic engineering, Beijing Institute of Technology, Beijing 100081, china 2 department of Electronic engineering, Beihang university , Beijing 100191, china 3 Institute of Electronics,Chinese Academy of Sciences, Beijing 100190, china 1. department of Electronic engineering Beijing Institute of Technology Beijing 100081 China2. Department of Electronic Engineering Beihang University Beijing 100191 China3. Institute of Electronics Chinese Academy of Sciences Beijing 100190 China

TOPS (terrain observation by progressive scans) is a recently proposed SAR mode for wide swath acquisition, which aims at achieving the same coverage and resolution as the SCAN mode besides creating scalloping-free images. In this paper, a general SAR imaging model used in TOPS and other SAR modes is introduced, where the antenna sweep rate, Doppler centroid rate, illumination time and azimuth resolution are described by a parameter defined as the "mode factor". After analyzing the characteristics of TOPS signal, an algorithm based on chirp-z transform is proposed, in which a new de-rotation function is used. Simulation results validate the proposed algorithm.

关键词： synthetic aperture radar acquisition mode TOPS

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Updating verbal and visuospatial working memory: Are the processes parallel?

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Chinese Science Bulletin 2008年第14期53卷 2175-2185页

作者： YUE ZhenZhu1,2, ZHANG Ming3,4 & ZHOU XiaoLin1 1 department of Psychology, Peking university, Beijing 100871, china 2 Biological Psychology and Neuropsychology, university of Hamburg, Von-Melle-Park 11, 20146 Hamburg, Germany 3.department of Psychology, northeast Normal university, Changchun 130024, china 4 Key Laboratory for Applied Statistics of MOE, northeast Normal university, Changchun 130024, china NE Normal Univ Dept Psychol Changchun 130024 Peoples R China.

The current study compared the processes of updating verbal and visuospatial working memory (WM) and examined the roles of central executive and slave systems in working memory updating tasks, by changing the number of items updated simultaneously to manipulate the load on central executive. Ex- periment 1 used the verbal WM updating task, and the results validated the efficiency of the paradigm to manipulate the load on central executive. Experiment 2 employed the verbal WM updating task, with the articulatory suppression task to interfere with the phonological loop. The results supported the study by Morris and Jones, revealing that the central executive system played an important role in the updating component of verbal WM, while the phonological loop was responsible for the serial recall component. Experiment 3 employed the visuospatial WM updating task, with the spatial tapping task to interfere with the visuospatial sketchpad. The results suggested that the visuospatial sketchpad and the central execu- tive together dealt with the updating component, while the visuospatial sketchpad was responsible for the serial recall component by itself. These results are consistent with the findings that visuospatial sketch- pad has close links with central executive, while the phonological loop is separated from the central ex- ecutive. It suggests that updating visuospatial and verbal WM are not two parallel processes.

关键词：记忆储存工作记忆中枢神经视觉性

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