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Spectral Radius of Non-negative Matrices and Digraphs

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Acta Mathematica Sinica,English Series 2002年第2期18卷 293-300页

作者： ZHANG Xiao Dong department of Mathematics.{1. china normal university,shanghai 200062.P.R.china E-mail:xdzhang2@hotmail.comLI Jiong Sheng department of Mathematics.university of Science and Technology of china,Hefei 230026,P.R china department of Mathematics East China Normal University Shanghai P. R. China department of Mathematics University of Science and Technology of China Hefei P. R. China

We present,an upper and a lower bound for the spectral radius of non-negative matrices. Then we give the bounds for the spectral radius of digraphs.

关键词： Non-negative matrix Digraph Spectral radius

Dynamic mechanism of the upwelling on the west side of the submerged river valley off the Changjiang mouth in summertime

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Chinese Science Bulletin 2003年第24期48卷 2754-2758页

作者： zhu Jianrong State Key Laboratory of Estuarine and Coastal Research, {1. china normal university, shanghai 200062, china Correspondence should be addressed to zhu Jianrong (e-mail: jrzhu@ ***) State Key Laboratory of Estuarine and Coastal Research East China Normal University Shanghai

Based on the analysis of the field observation data off the Changjiang mouth in August 2000 and satellite image of sea surface temperature (SST) in summer of 1.97, it indicates that there exists the upwelling event on the west side of the submerged river valley (SRV) off the Changjiang mouth. The calculated results of the three-dimensional nu-merical model show that this upwelling is induced by the barotropic effect, baroclinic effect, bottom Ekman effect and their interaction with the slope bottom topography. The baroclinic effect is the main cause producing the upwelling at the northern SRV (on the east side of the South Passage of the Changjiang estuary), while the barotropic effect is the main cause at the southern SRV (on the east side of the cen-ter of the Hangzhou Bay mouth). The dynamic mechanism producing the upwelling off the Changjiang mouth is differ-ent with the general one along coast and on the continental shelf.

关键词：动力学机制长江口夏季上升流数字仿真

Schwarz-Pick estimates for positive real part holomorphic functions on unit ball and polydisc

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Science china Mathematics 2010年第4期53卷 1017-1024页

作者： LIU Yang 1.& CHEN ZhiHua 2 1.department of Mathematics,Zhejiang {1. university,Jinhua 321.04,china 2 department of Mathematics,Tongji university,shanghai 200092,china 1. department of Mathematics Zhejiang Normal University Jinhua 321004 China2. Department of Mathematics Tongji University Shanghai 200092 China

We give higher order derivatives Schwarz-Pick estimates for all positive real part holomorphic functions on Bn and D n,and generalize early work on Schwarz-Pick estimate of higher order derivatives for holomorphic fun... 详细信息

关键词： Schwarz-Pick estimate holomorphic function Taylor expansion

Fabrication of ZnO-based thick film varistors with high potential gradient

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Rare Metals 2010年第4期29卷 390-395页

作者： KE Lei JIANG Dongmei MA Xueming State Key Laboratory of Precision Spectroscopy Department of Physics East China Normal University Shanghai 200062 China

ZnO-based thick film varistors have been fabricated by Y203 doping and low-temperature sintering, of which the sample with the best electrical properties has a high potential gradient value of 31.9.4 V/mm. The effects of Y2O3 doping concentration and sintering temperature on the potential gradient of the samples were systematically investigated. The results show that the sample with the best electrical properties can be obtained by doping 0.08 mol% Y2O3 and sintering at 725℃. Under these optimum preparation conditions, the leakage current and the nonlinear coefficient are found to be 36.4 gA and 1..1. The sample with the best electrical properties has a grain size of 1.290um, a single grain boundary voltage of 4.08 V, a barrier height of 0.81.eV, and a depletion layer width of 1..2 nm, which are determined by thermionic emission. Small grain size with good grain boundary characteristics is beneficial to improve the electrical properties of varistors and promote the potential gradient.

关键词： condensed matter physics thick film varistors low-temperature sintering doping potential gradient

Density functional study on enantioselective reduction of keto oxime ether with borane catalyzed by oxazaborolidine

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Science china Chemistry 2006年第4期49卷 296-307页

作者： LI Ming1. ZHENG Wenxu2 & TIAN Anmin2 1. department of Chemistry, Southwest-{1. normal university, Chongqing 40071., {1. 2. department of Chemistry, Sichuan university, Chengdu 61.064, {1. 1. department of Chemistry Southwest-China Normal University Chongqing 400715 China 2. department of Chemistry Sichuan University Chengdu 610064 China

The enantioselective reduction of keto oxime ether with borane catalyzed by oxazaborolidine is discussed by the density functional theory (DFT) method. The main intermediates and transition states for this reaction are optimized completely at the B3LYP/6-31.(d) level, and the transition states are verified by vibrational modes. As shown, the chirality-controlled steps for this re- action are the hydride transfer from borane to carbonyl carbon and oxime carbon of keto oxime ether, and the chirality for the reduced products is determined in these two reaction steps. In all examined reaction paths, the first hydride is transferred via a six-membered ring and the second hydride via a five-membered ring or a four-membered ring.

关键词： keto oxime ether, oxazaborolidine, enantioselective reduction, DFT.

Theoretical study on thermal decomposition of azoisobutyronitrile in ground state

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Science china Chemistry 2004年第5期47卷 373-380页

作者： SUN Chengke1.2, ZHAO Hongmei1.& LI Zonghe1.1. department of Chemistry, Beijing {1. university, Beijing 1.0875, china 2. department of Chemistry, Qujing {1. College, Qujing 655000, china 1. department of Chemistry Beijing Normal University 100875 Beijing China 2. department of Chemistry Qujing Normal College 655000 Qujing China

The thermal decomposition mechanisms of azoisobutyronitrile (AIBN) in the ground state have been investigated systematically. Based on the potential energy surfaces (PES) of various possible dissociation paths obtained using the semiempirical AM1.method with partial optimization, the density function theory B3LYP/6-31.G* method was employed to optimize the geometric parameters of the reactants, the intermediates, the products and the transition states, which were further confirmed by the vibrational analysis. The obtained results show that the re- action process of the two-bond (three-body) simultaneous cleavage Me2(CN)C─ N=N─ C(CN)Me2? 2Me2(CN)C?+N2 is much more favorable than the reaction process of the two one- bond asynchronous cleavage Me2(CN)CN=N─C(CN)Me2 ? Me2(CN)CN=N?+ Me2(CN)C?? Me2(CN)C?+ N2. It was suggested that the electron shrinking effect of double bond (─N=N─) in AIBN and the stabilities of the Me2(CN)C?radical as well as N2 molecule are main factors of leading to the reaction proceeding in the former pathway. The calculation results were consistent with all the experimental facts.

关键词： azoisobutyronitrile, radicals, thermal decomposition, density function theory (DFT).

THE GPL-STABILITY OF RUNGE-KUTTA METHODS FORDELAY DIFFERENTIAL SYSTEMS

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Journal of Computational Mathematics 2000年第1期18卷 75-82页

作者： Biao Yang Lin Qiu Jiao-xun Kuang(department of Mathematics, {1. normal university, {1. 200234, china.) 上海师范大学上海 200234

Presents a study which dealt with stability of the implicit Runge-Kutta methods for the numerical solutions of the systems of delay differential equations. Stability behavior of the methods; Exponential solutions of t... 详细信息

关键词： delay differential equation implicit Runge-Kutta methods GPL-stability

THE TOPOLOGICAL AND DYNAMICAL PROPERTIES OF NONORIENTABLE SURFACES

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Chinese Annals of Mathematics 1988年第2期9卷 197-206页

作者：朱德明 department of Mathematics {1. china normal university shanghai china.

Four topological and dynamical properties of nonorientable surfaces are *** is that for every continuous flow defined on any nonorientable closed surface,thereexist periodic or singular closed *** the case of the projective plane,it confirms aconjecture of professor Ye Yian-qian in his lecture notes“dynamical systems on surfaces”.Secondly,the author gives an exact upper bound of the number of closed curves onnonorientable surfaces,which do not intersect each other and the complement of their sumis still *** third is concerned with the upper and lower bound of the number ofthe periodic or singular closed orbits with certain *** last is related to theconnectedness of the complement of a lifting curve on two-fold covering *** firstproperty may be considered as a generalization of Kneser theorem from Klein bottle togeneral nonorientable surfaces and the second as a generalization of[4]Theorem 9.3.6from orientable surfaces to nonorientable surfaces.

关键词： Th THE TOPOLOGICAL AND DYNAMICAL PROPERTIES OF NONORIENTABLE SURFACES PCO

SADDLE VALUES AND INTEGRABILITY CONDITIONS OF QUADRATIC DIFFERENTIAL SYSTEMS

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Chinese Annals of Mathematics 1987年第4期8卷 466-478页

作者：朱德明 department of Mathematics {1. china normal university shanghai china.

In the first section of the paper,the first three saddle values R1.R2,R3 of the realquadratic differential system（QDE） are computed by use of the method with which Poincaréresearchs on Hopf *** the second section,by applying the method and results ofDulac seeking integrability conditions of QDE it is proved that the system is integrable ifand only if R1.R2=R3=0,and it is also true when the system is *** integrabilityconditions given here can be applied much more easily then Dulac’*** the last part ofthe paper,it is pointed out that iR1.iR2,iR3 are the first three focal values of the weakfocus of the complex *** the formulae of R1.R2,R3 and the result in section 2,one can easily give the formulae of the focal values for the real QDE with Bautin formand give a new proof of Bautin’s famous result.

关键词：鲁一 Za SADDLE VALUES AND INTEGRABILITY CONDITIONS OF QUADRATIC DIFFERENTIAL SYSTEMS