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Hereditary C~*-subalgebras and comparison of positive elements

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Science china Mathematics 2010年第6期53卷 1565-1570页

作者： WEI ChangGuo1,& WANG LiGuang2 1school of mathematical sciences,Ocean university of china,Qingdao 266071,china 2school of mathematical sciences,Qufu Normal university,Qufu 273165,china school of mathematical sciences Ocean University of China Qingdao China school of mathematical sciences Qufu Normal University Qufu China

Characterizations of hereditary subalgebras generated by subsets of a C*-algebra are given through open *** these results,we give some equivalent conditions of comparison of positive elements.

关键词： hereditary subalgebra open projection positive element

Local 3-cocycles of von Neumann algebras

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Science china Mathematics 2007年第9期50卷 1240-1250页

作者： Cheng-jun HOU~(1+) Ben-yin FU~2 1 school of mathematical sciences,Qufu Normal university,Qufu 273165,china 2 school of mathematical sciences,Fudan university,Shanghai 200433,china school of mathematical sciences Qufu Normal University Qufu China school of mathematical sciences Fudan University Shanghai China

We show that every local 3-cocycle of a von Neumann algebra $\mathcal{R}$ into an arbitrary unital dual $\mathcal{R}$ -bimodule $\mathcal{S}$ is a 3-cocycle.

关键词： von Neumann algebra dual bimodule local 3-cocycle 3-cocycle 46L10

On the number of B_(π')-characters in a nilpotent π-block

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Science china Mathematics 2008年第1期51卷 1-4页

作者： HAI JinKe~(1+) & ZHU YiXin~2 1 school of mathematical sciences, Qingdao university, Qingdao 266071, china 2 school of mathematical sciences, Capital Normal university, Beijing 100037, china school of mathematical sciences Qingdao University Qingdao China school of mathematical sciences Capital Normal University Beijing China

Brouéand Puig set the definition of nilpotent p-blocks, stated the existence of such blocks, and then proved that there is a unique Brauer character in a nilpotent p-block. The present paper, based on the works of Slattery and Robinson, generalizes the above idea to theπ-block theory of aπ-separable group, defines the nilpotency of aπ-block, and proves that there is a unique B_(π')-character in a nilpotentπ-block.

关键词： π-separable groups π-blocks π-subpairs nilpotentπ-blocks

Effects of Current Frequency on the Microstructure and Wear Resistance of Ceramic Coatings Embedded with SiC Nano-particles Produced by Micro-arc Oxidation on AZ91D Magnesium Alloy

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Journal of Materials Science & Technology 2010年第10期26卷 865-871页

作者： Yue Yang and Hua Wu Key Laboratory of Advanced Structural Materials,Ministry of Education,changchun university of Technology,changchun 130012,china Key Laboratory of Advanced Structural Materials Ministry of Education Changchun University of Technology Changchun 130012 China

To improve the surface wear resistance of the ceramic coating fabricated by micro-arc oxidation （MAO） on AZ91D magnesium alloy,ceramic coatings embedded with SiC nano-particles at different current frequency （500 Hz,700 Hz,and 900 Hz） were produced during the MAO *** morphology and phase composition of the coatings were investigated by scanning electron microscopy （SEM）,field emission scanning electron microscopy （FESEM）,and X-ray diffraction （XRD）.The surface roughness of the coatings was characterized by confocal laser scanning microscopy （CLSM）.Simultaneously,the tribological properties of the composite coatings were evaluated by using a universal materials tester （UMT）.The results shows that the wear resistance of the ceramic coatings with SiC nano-particles was improved significantly compared to the ceramic coatings without SiC ***,the composite coating formed at current frequency 900 Hz showed the better wear resistance than the others.

关键词： Magnesium alloy Micro-arc oxidation SiC nano-particles Wear resistance

Brake subharmonic solutions of first order Hamiltonian systems

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Science china Mathematics 2010年第10期53卷 2719-2732页

作者： LI Chong & LIU ChunGen school of mathematical sciences and LPMC,Nankai university,Tianjin 300071,china school of mathematical sciences and LPMC Nankai University Tianjin China

In this paper,we mainly use the Galerkin approximation method and the iteration inequalities of the L-Maslov type index theory to study the properties of brake subharmonic solutions for the first order non-autonomous Hamiltonian *** prove that when the positive integers j and k satisfy the certain conditions,there exists a jT-periodic nonconstant brake solution zj such that zj and zkj are distinct.

关键词： brake subharmonic solution L-Maslov type index Hamiltonian systems

Micromagnetic Simulation of Demagnetization Curves for Single-Phase Nanocrystalline Nd-Fe-B Magnet

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Journal of Materials Science & Technology 2000年第2期16卷 107-108页

作者： Hanmin JIN, Sufen ZHAO and Xuefeng WANG (Department of Physics, Jinn university, changchun 130012, china) Department of Physics Jilin University Changchun 130012 China

The demangetization curves for the nanocrystalline Nd-Fe-B magnets of the stoichiometric composition were calculated by using the finite element technique of micromagnetism. The curve, especially iHc become smaller with increase of *** most small iHc from a series of the curves along different field directions is closer to that for N=∞. iHc increases with increase of L, and are close cr some what smaller than that the experimental values should be.

关键词： Simulation Nd Fe

Raising approximation order of refinable vector by increasing multiplicity

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Science china Mathematics 2006年第1期49卷 86-97页

作者： YANG Shouzhi & PENG Lizhong Department of Mathematics, Shantou university, Shantou 515063, china LMAM, school of mathematical sciences, Peking university, Beijing 100871, china Department of Mathematics Shantou University Shantou China LMAM School of Mathematical Sciences Peking University Beijing China

An algorithm is presented for raising an approximation order of any given orthogonal multiscaling function with the dilation factor a. Let φ(x) = [φ1(x),φ2(x),…,φr(x)]T be an orthogonal multiscaling function with the dilation factor a and the approximation order m. We can construct a new orthogonal multiscaling function φnew(x) = [ φT(x). f3r+1(x),φr+2(x),…,φr+s(x)}T with the approximation order m + L(L ∈ Z+). In other words, we raise the approximation order of multiscaling function φ(x) by increasing its multiplicity. In addition, we discuss an especial setting. That is, if given an orthogonal multiscaling function φ(x) = [φ1 (x), φ2(x), …, φr(x)]T is symmetric, then the new orthogonal multiscaling function φnew(x) not only raise the approximation order but also preserve symmetry. Finally, some examples are given.

关键词： orthogonal, multiscaling functions, approximation order, symmetry.

BRILL-NOETHER MATRIX FOR RANK TWO VECTOR BUNDLES

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Chinese Annals of Mathematics,Series B 2002年第4期23卷 531-538页

作者： TAN XIAOJIANGschool of mathematical sciences, Peking university, Beijing 100871, china school of mathematical sciences Peking University Beijing 100871 China

Let X be an arbitrary smooth irreducible complex projective curve, E (?)X a rank two vector bundle generated by its sections. The author first represents ?as a triple {D1,D2,f}, where D1 , D2 are two effective divisors with d = deg(D1) + deg(D2), and f ∈ H?X, [D1] |D2) is a. collection of polynomials. E is the extension of [D2] by [D1] which is determined by f. By using / and the Brill-Noether matrix of D1+D2, the author constructs a 2g × d matrix WE whose zero space gives Im{H0(X,[D1]) (?) H0(X, [D1] |D1)}(?) Im{H?X, E) (?) H0(X,[D2]) (?) H0(X, [D2]|D2)} From this and H0(X,E) = H0(X,[D1]) (?)Im{H0(X,E) (?) H0(X, [D2])}, it is got in particular that dimH0(X, E) = deg(E) - rank(WE) + 2.

关键词： Brill-Noether matrix Vector bundle Effective divisor

NUMERICAL COMPUTATION OF BOUNDED SOLUTIONS FORA SEMILINEAR ELLIPTIC EQUATION ON AN INFINITE STRIP

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Journal of Computational Mathematics 1999年第2期17卷 159-170页

作者： Fu-ming Ma(Department of Mathematics, jilin ’university, changchun 130023, china) 吉林大学数学系吉林长春

In this paper, we consider the computation of bounded solutions of a semilinear elliptic equation on an infinite strip. The dynamical system approach and reduction on center manifold are used to overcome the difficult... 详细信息

关键词： numerical method nonlinear PDE center manifold