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A note on noncommutative moment problems

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Science China Mathematics 2005年第8期48卷 1144-1151页

作者： MA Xiujuan School of Sciences, Hebei University of Technology, Tianjin 300130, China Mathematics Institute, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, Beijing 100080, China School of Sciences Hebei University of Technology Tianjin China Mathematics Institute Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing China

Noncommutative moment problems for C*-algebras are studied. We generalize a result of Hadwin on tracial states to nontracial case. Our results are applied to obtain simple solutions to moment problems on the square and the circle as well as extend the positive unital functionals from a (discrete) complex group algebra to states on the group C*-algebra.

关键词： moment, free product, state, group C*-algebra.

A Legendre orthogonal moment based 3D edge operator

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Science China(Physics,Mechanics & Astronomy) 2005年第1期48卷 1-13页

作者： J.L.Dillenseger LTSI University of Rennes IFrance

This paper presents a new 3D edge operator based on Legendre orthogonal moments. This operator can be used to extract the edge of 3D object in any window size,with more accurate surface orientation and more precise surface location. It also has full geometry meaning. Process of calculation is considered in the moment based *** can greatly speed up the computation by calculating out the masks in advance. We integrate this operator into our rendering of medical image data based on ray casting algorithm. Experimental results show that it is an effective 3D edge operator that is more accurate in position and orientation.

关键词： Legendre moment, 3D edge operator, surface location, surface orientation, ray casting.

Electronic structure and magnetic properties of metastable SmCo_(7) compound

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Science China(Physics,Mechanics & Astronomy) 2005年第3期48卷 325-335页

作者： ZHANG Changwen 1 , LI Hua 1 , DONG Jianmin 1 , WANG Yongjuan 1 , PAN Fengchun 1 , ZHANG Jian 1 , GUO Yongquan 2 & LI Wei 2 1. School of Physics and Microelectronics, Shandong University, Jinan 250100, China 2. Institute of Functional Materials, Central Iron and Steel Research Institute, Beijing 100081, China School of Physics and Microelectronics Shandong University Jinan China Institute of Functional Materials Central Iron and Steel Research Institutes Beijing China

The electronic density of states, spin-splittings and atomic magnetic moments of SmCo 7 compound have been studied using spin-polarized MS-Xα method. The results show that a few of electrons are transferred to Sm(5d 0 ) orbital because of orbital hybridization between Sm and Co atoms in the compound. The exchange interactions between 3d and 5d electrons lead to the magnetic coupling between Sm and Co, and therefore, result in the long-range ferromagnetic order inside the SmCo 7 compound. There are negative exchange couplings occurring at some levels, which weakens the strength of average coupling around Co lattice. So, the Curie temperature and Co-moment of SmCo 7 decrease distinctly compared with pure Co. Compared with SmCo 5 compound, the disordered substitution of Co-Co “dumbbell-atom” pairs for Sm changes the local environment of Co lattice, which makes the 2e site bear negative magnetic moment. The strength of hybridization near Fermi level weakens and the free energy of the compound increases obviously. Thus, SmCo 7 is a metastable compound at room temperature. Considering the localization of 4f electrons and a few of 5d electrons arising from the orbital hybridization, the magnetic moment of Sm atom will be 1.61μ B in SmCo 7 compound, which is in agreement with the experimental values of Sm 3+ ion- moment and Sm atom-moment in metals.

关键词： electronic structure, spin polarization, atomic magnetic moment, exchange coupling, Curie temperature.

Electronic structure and magnetic properties of SmCo7-xTix

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Science China(Physics,Mechanics & Astronomy) 2006年第1期49卷 38-45页

作者： ZHANG Changwen1, LI Hua1, DONG Jianmin1, GUO Yongquan2 & LI Wei2 1. School of Physics and Microelectronics, Shandong University, Jinan 250100, China 2. Institute of Functional Materials, Central Iron and Steel Research Institute, Beijing 100081, China School of Physics and Microelectronics Shandong University Jinan China Institute of Functional Materials Central Iron and Steel Research Institute Beijing China

Electronic structure of SmCo7-xTix alloy has been studied by means of the spin-polarized MS-Xα method. It is shown that a few of electrons are transferred to Sm(5d) orbital due to orbital hybridization between Sm and Co atoms. The exchange interaction between 5d-3d electrons is stronger, which is the main reason resulting in the long-range ferromagnetic order between Co and Sm atoms. The Curie temperature of SmCo7-xTix is generally lower than that of pure Co metal, which may be explained by the weaker aver- age of coupling strength between Co sites due to some negative exchange couplings occurring mainly at 2e site. The calculated results for the Sm5Co28Ti6 cluster may lead to a better understanding of why SmCo7-xTix is stable phase. Since the negative interaction of 2e sites weakens and the bonding at EF strengthens with increasing Ti concentration, which result in the decrease in the free energy of the alloy, the stable ferromagnetic order forms inside SmCo7-xTix. Considering the localization of 4f states and 5d moment arising from the orbital hybridization, the calculated moment is 9.47μB per formula unit that is in agreement with experiments.

关键词： electronic structure, spin polarization, atomic magnetic moment, exchange coupling, Curie temperature.

Dependence of nucleotide physical properties on their placement in codons and determinative degree

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2005年第10期6卷 948-960页

作者： BEREZHNOY A.Y. DUPLIJ S.A. NSC Kharkov Institute of Physics and Technology Kharkov 61108 UkraineDepartment of Physics and Technology Kharkov National University Svoboda Sq.4 Kharkov 61077 Ukraine

Various physical properties such as dipole moment, heat of formation and energy of the most stable formation of nucleotides and bases were calculated by PM3 (modified neglect of diatomic overlap, parametric method number 3) and AM1 (austin model 1) methods. As distinct from previous calculations, for nucleotides the interaction with neighbours is taken into account up to gradient of convergence equaling 1. The dependencies of these variables from the place in the codon and the de- terminative degree were obtained. The difference of these variables for codons and anticodons is shown.

关键词： Dipole moment, Heat of formation, Total energy, DNA, Codon, Anticodon, Determinative degree

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一种圆管弯曲力矩计算公式及其验证（英文）

机床与液压 2016年第6期44卷 82-87页

作者： Lei WU Kai-dong HUANG Department of Equipment Manufacturing Zhongshan Torch Polytechnic Zhongshan 528437 China School of Mechanical and Automotive Engineering South China University of Technology Guangzhou 510641 China

The combination of the traditional pipe-bending technology and the CNC technology of machine tool there is no fixed size and material specifications. Moreover,make the pipe bending process automation. However,the non-linear relationship between the bending moment and the sizes brings troubles in choosing an electric ma-chine of the CNC pipe-bending device. Therefore, this paper presents a formula to calculate the pipe-bending mo-ment, for improving the calculating efficiency and reducing the testing cost. The numerical simulation and experi-mental test were carried out to verify the accuracy of the formula, respectively. The result shows that the presentedformula is effective in solving the engineering problems.

关键词： Pipe-bending, Bending moment, Theoretical formula