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About the Energy of the Universe

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Chinese Physics Letters 1996年第6期13卷 409-411页

作者： FENG Shi-xiang duan yi-shi Institute of Nuclear Research Chinese Academy of SciencesShanghai 201800 Institute of Theoretical Physics Lanzhou UniversityLanzhou 730000

We use the general covariant conservation law of energy-momentum,which is general covariant and therefore preferable to the non-covariant conservation laws,to analyse the energy of the universe and obtained vanishing ... 详细信息

关键词： energy vanishing discussions

Anomalous Optical and Electronic Properties of CaTiO3 Perovskites

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Communications in Theoretical Physics 2007年第3X期48卷 563-570页

作者： LIU Hui-Ping duan yi-Feng yi Lin Department of Physics and State Key Laboratory of Laser Technology Huazhong University of Science and TechnologyWuhan 430074 China

With the help of the first-prlnciples full potential linearized augmented plane wave method, absorption coefficients, reflect/vity, dielectric behavior and electronic properties, including electronic energy bands, density of states and charge density distributions, are studied for the tetragonal and cubic CaTiO3. By considering the thermal expansion effects, an approximate method is proposed for the study of the stability of ground state and a tendency of phase transition, based on the minimum free energy principle. Subsequently, numerical calculations are carried out by using the first-principles perturbation method. We demonstrate that the high-temperature phase is cubic. It is shown that optical spectra in tetragonal phase exhibit single-peak feature and differ from multi-peak character in cubic. We find that strong orbital hybridization results in the co-valent bonds between Ti 3d and O 2p electrons and forms two-type dipoles （Ti-Ol and Ti-02） in tetragonal, while the Ti-O dipoles are identical in cubic. It is argued that crystal structure determines the dipole distributions and leads to some electron states among which the dipole-dipole transit/on forbidden is a key, causing such anomalous optical phenomena with the insulator characteristics. The predicted charge density distribution and the tendency of phase transition from tetragonal to cubic are in good agreement with experimental observations.

关键词： first-principles calculations CaTiO3 perovskites optical and electronic properties

Hydrogen isotopic compositions and their environmental significance for individual n-alkanes in typical plants from land in China

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Chinese Science Bulletin 2009年第3期54卷 461-467页

作者： duan yi WU BaoXiang Institute of Geology and Geophysics Chinese Academy of Sciences Lanzhou 730000 China

Hydrogen isotopes of n-alkanes in grasses, tree leaves and reeds from six regions with latitudes of 20° to 39°N in China are measured by GC-TC-IRMS analytical technique in order to understand their hy- drogen isotopic compositions and environmental significance. The results show that a difference in δ D values (from -42.1‰ to -66.6‰) of n-alkanes exists among the same kinds of plants from various re- gions. Hydrogen isotopic compositions of most even carbon numbered n-alkanes in every plant are slightly heavier than that of the odd homologues. A trend toward D-enrichment with increasing chain length of n-alkanes in most plant samples is observed. Mean δ D values of n-alkanes in the studied plants range from -202.6‰ to -130.7‰ and the reed from a salt marsh has the largest value. The mean δ D values of individual n-alkanes among the same kinds of plants from various regions have the characteristics of leaf > reed > grass. The hydrogen isotopic compositions of n-alkanes are apparently distinct among various kinds of plants from the same region and the mean δ D values exhibit a distri- bution of tree leaf > reed > grass. It is observed that the mean δ D values of n-alkanes and δ D values of C27 and C29 n-alkanes in the grasses and tree leaves from these studied regions correlate clearly nega- tively with latitude and positively with temperature, indicating that these values can be used as excel- lent indicators of environment and climate. These results provide important basic data for under- standing the distributional law of hydrogen isotopes of individual n-alkanes and their applied research.

关键词：植物学氢同位素合成分布环境指数

Carbon isotopic studies of individual lipids in organisms from the Nansha sea area, China

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Science China Earth Sciences 2004年第7期47卷 593-598页

作者： duan yi SONG Jinming ZHANG Hui Lanzhou Institute of Geology Chinese Academy of SciencesLanzhou 730000China School of Geology Lanzhou UniversityLanzhou 730000China Institute of Oceanology Chinese Academy of SciencesQingdao 266071China

Carbon isotopes of individual lipids in typical organisms from the Nansha sea area were measured by the GC-IRMS analytical technique. δ13C values of saturated fatty acids in different organisms examined are from 25.6‰ to 29.7‰ with the average values ranging from 26.4‰ to 28.2‰ and the variance range of 1.8‰ between different organisms is also observed. Unsaturated fatty acids have heavy carbon isotopic compositions and the mean differences of 2.9‰–6.8‰ compared to the same carbon number saturated fatty acids. δ13C values of n-alkanes range from 27.5‰ to 29.7‰ and their mean values, ranging from 28.6‰ to 28.9‰, are very close in different organisms. The mean difference in δ13C between the saturated fatty acids and n-alkanes is only 1.5‰, indicating that they have similar biosynthetic pathways. The carbon isotopic variations between the different carbon-number lipids are mostly within ±2.0‰, reflecting that they experienced a biosynthetic process of the carbon chain elongation. At the same time, the carbon isotopic genetic relationships between the biological and sedimentary lipids are established by comparative studies of carbon isotopic compositions of individual lipids in organisms and sediments from the Nansha sea area, which provides scientific basis for carbon isotopic applied research of individual lipids.

关键词： marine organisms individual lipids carbon isotopic compositions genetic relationships DOI: 10.1360/03yd0561

Inner Structure of Statistical Gauge Potential in Chern-Simons-Ginzburg-Landau Theory

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Communications in Theoretical Physics 2005年第3X期44卷 559-562页

作者： duan yi-Shi ZHANG Xiu-Ming Institute of Theoretical Physics Lanzhou University Lanzhou 730000 China

Based on the decomposition theory of the U（1） gauge potential, the inner structure of the statistical gauge potential in the Chern-Simons-Ginzburg-Landau （CSGL） theory is studied. We give a new creation mechanism of the statistical gauge potential, Furthermore, making use of the b-mapping topological current theory, we obtain the precise topological expression of the statistical magnetic field, which takes the topological information of the vortices.

关键词： gauge potential decomposition theory topological quantum mechanics

Topological Structure of Phase Vortex in Resonating Valence Bond Superconductivity

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Communications in Theoretical Physics 2006年第1X期46卷 33-36页

作者： SHI Xu-Guang duan yi-Shi College of Basic Science and Technology Beijing Forestry University Beijing 100083 China Institute of Theoretical Physics Lanzhou University Lanzhou 730000 China

In this paper, based on the Schrfdinger equation and the ψ mapping theory, the accurate expression for the gradient of resonating valence bond superconducting phase Θ^2s is found. The expression of Δ↓Θ^2s is just the velocity flow without considering the coefficient. The curl of Δ↓Θ^2s is where the vortex lies, and has important relation to δ2（ψ） and an important relation to the zero points of resonating valence bond superconducting order parameter ψ. The topological structure of the vortex is characterized by the ψ-mapping topological numbers Hopf-index and Brouwer degrees. The Ginzberg-Landau equation in resonating valence bond state also is discussed in this theory. The magnetic property is discussed also.

关键词： ψ-mapping theory phase vortex GL-equation RVB superconductivity

Generalized Dirichlet Normal Ordering in Open Bosonic Strings

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Communications in Theoretical Physics 2009年第1期51卷 110-114页

作者： CAO Zhen-Bin duan yi-Shi Institute of Theoretical Physics Lanzhou University Lanzhou 730000 China

Generally, open string boundary conditions play a nontrivial role in string theory. For example, in the presence of an antisymmetric tensor background field, they will lead the spacetime coordinates noncommutative. In this paper, we mainly discuss how to build up a generalized Dirichlet normal ordered product of open bosonic string embedding operators that satisfies both the equations of motion and the generalized Dirichlet boundary conditions at the quantum level in the presence of an antisymmetric background field, as the generalized Neumann case has already been discussed in the literature. Further, we also give a brief check of the consistency of the theory under the newly introduced normal ordering.

关键词： boundary conditions normal ordering

Surface Distribution of Topological Defects on Axisymmetric

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Communications in Theoretical Physics 2006年第2X期46卷 319-322页

作者： SI Tie-Yan duan yi-Shi Institute of Theoretical Physics the Chinese Academy of Sciences Beijing 100080 China Institute of Theoretical Physics Lanzhou University Lanzhou 730000 China

We propose a general method of deterrnining the distribution of topological defects on axisymmetric surface, and study the distribution of topological defects on biconcave-discoid surface, which is the geometric configuration of red blood cell. There are three most possible cases of the distribution of the topological defects on the biconcave surface： four defects charged with 1/2, two defects charged with ＋1, or one defect charged with 2. For the four defect charged with 1/2, they sit at the vertices of a square imbedded in the equator of biconcave surface.

关键词： topolotical defects membrane axisymmetric surface

Integer and Half-Integer Quantization Conditions in Quantum Mechanics

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Chinese Physics Letters 2001年第4期18卷 473-475页

作者： duan yi-Shi JIA Duo-Jie Institute of Theoretical Physics Lanzhou UniversityLanzhou 730000

The integer and half-integer quantization conditions are found in quantum mechanics based on the topological structure of symmetry group of the singlet and spinor *** internal symmetry of physical system is shown to be sufficient to determine the topological structure in quantum mechanics without taking into account the dynamical details about the interaction.

关键词： interaction. integer symmetry