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Explicit Solutions for a (2+1)-Dimensional Toda Lattice with Two Discrete Variables

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Communications in Theoretical Physics 2007年第10期48卷 667-670页

作者： WANG Zheng-Yan YANG Xiao Department of Mathematics,zhengzhou University,zhengzhou 450052.china Department of Mathematics Zhengzhou University

An integrable(2+1)-dimensional Toda lattice with two discrete variables is investigated again,which isproduced from a compatible condition of the Lax *** Darboux transformation for its spectral problems is *** an appl... 详细信息

关键词： Toda lattice two discrete variables Darboux transformation explicit solution

Classification of hypersurfaces with parallel Mobius second fundamental form in S^(n+1)

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Science china Mathematics 2004年第3期47卷 417-430页

作者： HU Zejun LI Haizhong Department of Mathematics, zhengzhou University zhengzhou 450052, china Department of Mathematical Sciences, Tsinghua University, Beijing 100084, china Department of Mathematics Zhengzhou University Zhengzhou China Department of Mathematical Sciences Tsinghua University Beijing China

Let Mn(n≥2) be an immersed umbilic-free hypersurface in the(n+1)-dimensional unit sphere Sn+1. Then Mn is associated witha so-called M(o)bius metric g, and a M(o)bius second fundamental form Bwhich are invariants of Mn under the M(o)bius transformation groupof Sn+*** this paper, we classify all umbilic-free hypersurfaces withparallel M(o)bius second fundamental form.

关键词： parallel Mobius second fundamental form,hypersurface, Mobius metric, Mobius equivalence.

Semisymmetric Cubic Graphs as Regular Covers of K3,3

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Acta Mathematica Sinica,English Series 2008年第3期24卷 405-416页

作者： Chang Qun WANG Tie Sheng CHEN Department of Mathematics,zhengzhou University,zhengzhou,450052,P.R.china Department of Mathematics Zhengzhou University Zhengzhou 450052 P. R. China

A regular graph X is called semisymmetric if it is edge-transitive but not *** G≤Aut X,we call a G-cover X semisymmetric if X is semisymmetric,and call a G-cover Xone-regular if Aut X acts regularly on its *** this paper,we give the sufficient and necessaryconditions for the existence of one-regular or semisymmetric Z-covers of ***,an infinite familyof semisymmetric Z×Z-covers of Kare constructed.

关键词： semisymmetric graph symmetric graph covering graph one-regular graph

Structure and magnetism of a porous three-dimensional metal-organic framework based on planar tetranuclear copper(Ⅱ) cluster units

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Science china Chemistry 2010年第10期53卷 2118-2122页

作者： LI HuiJun, ZHANG ErPeng, GUO QianQian, HOU HongWei & FAN YaoTing Department of Chemistry, zhengzhou University, zhengzhou 450052, china 1. Department of Chemistry Zhengzhou University Zhengzhou 450052 China

A porous three-dimensional copper(Ⅱ) metal-organic framework (MOF) {[Cu2(tci)(OH)(pip)0.5(H2O)]·6H2O}n (1) [tci = tris (2-carboxyethyl)isocyanurate, pip = piperazine] has been generated under hydrothermal conditions at 120 °C. Single crystal X-ray diffraction reveals that the polymer exhibits a novel three-dimensional framework based on planar tetranuclear copper(Ⅱ) cluster units. The variable temperature magnetic susceptibility data in the range 2-280 K show antiferromagnetic spin-spin coupling in the tetranuclear unit in complex 1. A theoretical fitting of the magnetic data gives J values of -31.3 cm-1, -30.8 cm-1, and 13.5 cm-1.

关键词： metal–organic framework tetranuclear copper cluster unit topology magnetism

SYNTHESIS AND CHARACTERIZATION OF ORGANOMONTMORILLONITE AND POLYAMIDE 66/MONTMORILLONITE NANOCOMPOSITES

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Chinese Journal of Polymer Science 2002年第6期20卷 551-557页

作者： Cheng-shen Zhu Xin Kang Su-qin He Liu-yang Wang Li-yun Lu College of Materials Engineering,zhengzhou University, zhengzhou 450052, china zhengzhou Univ Coll Mat Engn Zhengzhou 450052 Peoples R China

The montmorillonites (MMTs), layered, smectite-type silicates, were premodified by two different methods prior to the polymer melt intercalation. In one case MMTs were modified with cetyltrimethylammonium bromide (CTAB), and termed as organomontmorillonites (OMMTs); in the other case MMTs were modified by nylon, and the products were called modified montmorillonites (MMMTs). The effects of CTAB and nylon on the MMTs were investigated by using TG and WAXD. The results show that interlayer spacings of CTAB and nylon modified MMTs are larger than that of sodium MMTs. Then, polyamide 66 (PA 66)/MMT nanocomposites were obtained through the method of melt intercalation of polymers. The nanocomposites were characterized by WAXD, TEM and Molau experiments. The results indicate that the MMTs disperse homogeneously in the PA 66 matrix. The mechanical properties of nanocomposites, such as tensile properties and flexural properties, were also measured and show a tendency to increase with increase of MMT content and reach the maximum values at 5phr MMT content. The heat distortion temperature (HDT) of the nanocomposites (7 phr) is about 32 K higher than that of pure PA 66.

关键词： montmorillonite polyamide 66 nanocomposites melt intercalation

THE NP-HARDNESS OF THE SINGLE MACHINE COMMON DUE DATE WEIGHTED TARDINESS PROBLEM

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Systems Science and Mathematical Sciences 1992年第4期5卷 328-333页

作者： YUAN Jinjiang (Department of Mathematics,zhengzhou University,zhengzhou 450052.china)

In this paper we prove that the single machine common due dateweighted tardiness problem is NP-hard.

关键词： Due date tardiness NP-complete

A lumped mass nonconforming finite element method for nonlinear parabolic integro-differential equations on anisotropic meshes

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Applied Mathematics(A Journal of Chinese Universities) 2009年第1期24卷 97-104页

作者： SHI Dong-yang WANG Hui-min LI Zhi-yan Dept. of Math., zhengzhou Univ., zhengzhou 450052, china Dept. of Math. Zhengzhou Univ. Zhengzhou 450052 China

A lumped mass approximation scheme of a low order Crouzeix-Raviart type noncon- forming triangular finite element is proposed to a kind of nonlinear parabolic integro-differential equations. The L2 error estimate is d... 详细信息

关键词： nonlinear parabolic integro-differential equation nonconforming finite element anisotropic mesh lumped mass error estimate

Silicon nanoporous pillar array and its surface copper deposition

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Chinese Science Bulletin 2005年第14期50卷 1424-1428页

作者： FU Xiaonan1,2,3, CHAI Huadou1,2 & LI Xinjian1,2 1. Department of Physics, zhengzhou University, zhengzhou 450052, china 2. Key Laboratory of Material Physics (zhengzhou University), Ministry of Education, zhengzhou 450052, china 3. Department of Mathematics and Physics, Henan University of Tech- nology, zhengzhou 450052, china Department of Physics Zhengzhou University Zhengzhou 450052 China Key Laboratory of Material Physics (zhengzhou University) Ministry of Education Zhengzhou 450052 China Department of Mathematics and Physics Henan University of Technology Zhengzhou 450052 China

Silicon nanoporous pillar array (Si-NPA) has been prepared by a hydrothermal etching technique. Using Si-NPA as substrate, a Cu/Si-NPA nanocomposite thin film has been obtained with immersion plating method. Morpho- logical and structural analysis indicates that Si-NPA is a typical structural composite system characterized by a triple hierarchical structure, i. e. the array of micron-sized silicon pillars, the nanopores densely distributed on the surface of the pillars, and the silicon nanocrystallites that constitute the pore walls. Cu/Si-NPA inherits the morphological character- istics of Si-NPA. The compactability of the deposited copper nanoparticles varies alternatively with the local geometrical features of Si-NPA and forms a quasi-periodical pattern. Such an experimental phenomenon is attributed to the veloc- ity dependence of the copper deposition upon the local geo- metrical features of Si-NPA. These results indicate that Si-NPA might be used as an ideal template for preparing specially patterned, structured or functionalized metal/ sili- con nanocomposite systems.

关键词：硅元素薄膜蚀刻技术电镀技术

A Target Recognition Approach to Projecting HRR Profiles onto Subspace

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Journal of Systems Engineering and Electronics 2003年第1期14卷 36-40页

作者： Pei Bingnan & Bao ZhengKey Lab. of Radar Signal Processing, Xidian University, Xi’an 710071, P. R. china Dept. of Electronic Engineering, zhengzhou University, zhengzhou 450052, P.R. china Key Lab. of adar Signal Processing Xidian University. Xi'an 710071 P. R. China Dept. of Electronic Engineering Zhengzhou University Zhengzhou 450052 P. R. China

Abstract: A array of the azimuthally averaged range-profile vectors and the inter-class and intra-class divergence matrixesare constructed iwth many frames of the high resolution range profiles which result from radar echoes of airplanes. Takingthe methods of whitening transformation and SVD produces a system of subspace vectors for target recognition. Where-upon, a template library for target recognition is built by the projection of a class-mean vector made from the radar dataonto the subspace for recognition. By Euclidean distance, a comparison is made between the above projection and eachtemplate in the library, to decide which class the target belongs to. Finally, simulations with the experimental radar dataarte given to show that the proposed method is robust to variation in azimuth and immune to additive Gaussian noisewhen SNR≥5dB.

关键词： Automatic target recognition High range resolution profile Distance classifier SVD Computer simulation