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On the Symmetry Classes of Functions

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Wuhan university Journal of Natural sciences 2005年第5期10卷 813-816页

作者： ZHU Ping~1,2. FAN Yun~3.1. school of Mathematics and Statistics, Wuhan {2., Wuhan 43.072. Hubei, china 2. school of Science, Beijing {2. of Posts and Telecommunications, Beijing 100876, china 3. school of Mathematics and Statistics, Huazhong Normal {2., Wuhan 43.079, Hubei, china school of Mathematics and Statistics Wuhan University Wuhan Hubei China school of Science Beijing University of Posts and Telecommunications Beijing China school of Mathematics and Statistics Huazhong Normal University Wuhan Hubei China

Let R be an integral domain of characteristic zero such that the corresponding group rings have block decompositions. We first prove that the submodule consisting of all the R-valued ξi-symmetric functions of several variables is a symmetry class, where ξi is any block character. Then we present a relationship among certain operators introduced for block character. Then we present a relationship among certain operators introduced for block characters. As a consequence, we obtain a decomposition of an arbitrary R-valued function of several variables. Finally, we describe the symmetry property of such summands and determine all the symmetry classes.

关键词： symmetry class strict symmetry class blockcharacter ξi-symmetric function block idempotent

Fractal Characteristics of Coal Pores Based on Classic Geometry and Thermodynamics Models

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Acta Geologica Sinica(English Edition) 2011年第5期85卷 1150-1162页

作者： CAI Yidong~1,LIU Dameng~(1,*),YAO Yanbin~1,LI Junqian~1 and LIU Junlai~2.1 school of Energy Resources,china {2. of {3.,Beijing 100083.china 2.school of earth Science and Resources,china {2. of {3.,Beijing 100083.china school of Energy Resources China University of Geosciences Beijing 100083 China school of earth Science and Resources China University of Geosciences Beijing 100083 China

To better understand the characteristics of coal pores and their influence on coal reservoirs, coal pores in eight main coalfields of North china were analyzed by mercury porosimetry and scanning electron microscopy（SEM）.Fractal characteristics of coal pores（size distribution and structure） were researched using two fractal models:classic geometry and *** two models establish the relationship between fractal dimensions and coal pores *** results include:（1） SEM imaging and fractal analysis show that coal reservoirs generally have very high heterogeneity;（2. coal pore structures have fractal characteristics and fractal dimensions characteristic of pore structures are controlled by the composition（e.g.,ash,moisture,volatile component） and pore parameters（e.g.,pore diameter,micro pores content） of coals;（3. the fractal dimensions（D;and D;） of coal pores have good correlations with the heterogeneity of coal pore *** fractal dimensions correlate to higher heterogeneity of pore *** fractal dimensions（D;and D;） have strong negative linear correlations with the sorted coefficient of coals （R;=0.719 and 0.63.,respectively） that shows the heterogeneity of coal pores;（4） fractal dimension D;and petrologic permeability of coals have a strong negative exponential correlation（R;=0.82..However, fractal dimension D;and petrologic permeability of coals have no obvious correlation;and（5） the model of classic geometry is more accurate for fractal characterization of coal pores in coal reservoirs than that of thermodynamics by optimization.

关键词： coal pores mercury porosimetry fractal dimensions thermodynamics model classic geometry model

Effect of rock mass structure and block size on the slope stability——Physical modeling and discrete element simulation

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Science china(Technological sciences) 2005年第Z1期48卷 1-17页

作者： LI Shihai1, LIAN Zhenzhong1,2.& J. G. Wang3.1. Institute of Mechanics, Chinese Academy of sciences, Beijing 100080, {2. 2. Graduate school, Chinese Academy of sciences, Beijing 100060, {2. 3. Tropical Marine Science Institute, National university of Singapore, Singapore 1192.0 Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China Graduate school Chinese Academy of Sciences Beijing 100060 China Tropical Marine Science Institute National University of Singapore Singapore 119260 Singapore

This paper studies the stability of jointed rock slopes by using our improved three-dimensional discrete element methods (DEM) and physical modeling. Results show that the DEM can simulate all failure modes of rock slopes with different joint configurations. The stress in each rock block is not homogeneous and blocks rotate in failure development. Failure modes depend on the configuration of joints. Toppling failure is observed for the slope with straight joints and sliding failure is observed for the slope with staged joints. The DEM results are also compared with those of limit equilibrium method (LEM). Without considering the joints in rock masses, the LEM predicts much higher factor of safety than physical modeling and DEM. The failure mode and factor of safety predicted by the DEM are in good agreement with laboratory tests for any jointed rock slope.

关键词： rock masses, slope stability, DEM simulation, block size effect, joints configuration effect, limit equilibrium method.

Effects of abnormally high heat stress on petroleum in reservoir——An example from the Tazhong 18 Well in the Tarim Basin

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Science china earth {2. 2008年第4期51卷 515-527页

作者： ZHU DongYa1, JIN ZhiJun1, HU WenXuan2.& ZHANG XueFeng3.1 Petroleum Exploration and Production Institute, china Petroleum & Chemical Corporation, Beijing {2. china 2.Department of {3. sciences, Nanjing university, Nanjing 2.0093. china 3.school of Resource and Information, china university of Petroleum, Beijing 102.49, china Petroleum Exploration and Production Institute China Petroleum & Chemical Corporation Beijing China Department of earth sciences Nanjing University Nanjing China school of Resource and Information China University of Petroleum Beijing China

An igneous intrusion of 94m thick was discovered intruding into the Silurian sandstone from Tazhong 18 Well. The petroleum previously preserved in the Silurian sandstone reservoir was altered into black carbonaceous bitumen by abnormally high heat stress induced by the igneous intrusion. The reflec-tance of the carbonaceous bitumen reaches as high as 3.54%, indicating that the bitumen had evolved into a high thermal evolution level. Similar to the Silurian samples from the neighboring Tazhong 11, Tazhong 12. Tazhong 45 and Tazhong 47 wells, the distribution of C2., C2. and C2. steranes of the car-bonaceous bitumen is still "V" -shaped and can still be employed as an efficient parameter in oil source correlation. The "V" -shaped distribution indicates that the hydrocarbons from the Tazhong 18 and the neighboring wells were all generated from the Middle-Upper Ordovician hydrocarbon source rocks. However, the oil source correlation parameters associated with and terpanes had been changed greatly by the high heat stress and can no longer be used in oil source correlation. The δ 13. values of the pe-troleum from the neighboring wells are between -3..53. and -3..3.‰, coincident with those of the Paleozoic marine petroleum in the Tarim Basin. However, the δ 13. values of the carbonaceous bitumen from the Tazhong 18 Well are between -2..18‰ and -2..2.‰, isotopically much heavier than the pe-troleum from the neighboring wells. The content of light hydrocarbons (nC14-nC2.) of the saturated hydrocarbon fraction in the carbonaceous bitumen is extremely higher than the content of heavy hy-drocarbons. The light/heavy hydrocarbon ratios (ΣnC2.-/ΣnC2.+) are between 4.56 and 3..17. In the saturated fraction, the even numbered hydrocarbons are predominant to the odd numbered, and the OEP (Odd to Even Predominance) values are between 0.2. and 0.49. However, the content of light hy-drocarbons in the petroleum from the neighboring wells is relatively low and the content of the even numb

关键词： Tarim Basin igneous intrusive abnormally high heat stress bitumen carbon isotope PAH

On conformal measures for infinitely renormalizable quadratic polynomials

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Science china Mathematics 2005年第10期48卷 1411-1420页

作者： HUANG Zhiyong~1 JIANG Yunping~(2.3. & WANG Yuefei~3.1. {2. of Information,Renmin university of china,Beijing 100872.china 2. Department of Mathematics,Queens College,City university of New York,NY 113.7,USA Department of Mathematics,Graduate {2.,City university of New York,New York,NY 10016,USA 3. Academy of Mathematics and Systems Science,Chinese Academy of sciences,Beijing 100080,china school of Information Renmin University of China Beijing China Department of Mathematics Queens College City University of New York NY USA Department of Mathematics Graduate School City University of New York New York USA Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing China

We study a conformal measure for an infinitely renormalizable quadratic polynomial. We prove that the conformal measure is ergodic if the polynomial is unbranched and has complex bounds. The main technique we use in t... 详细信息

关键词： Julia set, conformal measure, three-dimensional puzzle, infinitely renormalizable quadratic polynomial.

Nitrogen isotopic geochemical characteristics of crude oils in several basins of china

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Science china earth {2. 2005年第8期48卷 1211-1219页

作者： CHEN Chuanping1,2. MEI Bowen1 & CAO Yacheng3.1. Jianghan Petroleum university, Jingzhou 43.100, china 2. Huazhong university of Science and Technology, Wuhan 43.047, china 3. Nanjing Institute of Soil Science, Chinese Academy of sciences, Nanjing 2.0008, china Jianghan Petroleum university Jingzhou China Huazhong university of Science and Technology Wuhan China Nanjing Institute of Soil Science Chinese Academy of Sciences Nanjing China

Nitrogen isotopic ratios of crude oils with different physical and chemical properties in several basins of china have been measured and their geochemistry has been studied ele-mentally combined with molecular organic geochemistry methods. The data indicate that δ 15N is in the range of ?6‰-2.‰. They vary with the oils in different sedimentary types of basins. The oils forming in the limnic environment have lower δ 15N with the value of about 1‰-5‰ whereas the oils in saline or semi-saline environment have higher δ 15N, with most samples being above 10‰ and some exceeding 17‰. The average nitrogen isotopic ratio of oils from the Ordovician formation in the Tarim Basin is the lowest, with most samples having δ 15N below zero, which reflects possibly the characteristic of the oils originating mainly from the organic matter formed in marine carbonate sedimentary environment. The δ 15N distribution can be altered by fractionation. It increases obviously because of biodegradation and decreases during hydrocarbon migration. However, the effect of nitrogen isotopic fractionation in the short distance migration is uncon-spicuous.

关键词： nitrogen isotope, crude oil, sedimentary environment, isotopic fractionation, china.

The microbial metallogeny of weathering crust REE deposits in South china

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Chinese Science Bulletin 1999年第S2期44卷 71-73页

作者： CHEN Binghui~(1,2., WANG Zhimei~3. HUANG Limei~3. WU Fuhai~3. CHEN Jingde~2.and XU Wenlie~2.1. Department of earth sciences, Nanjing university, Nanjing 2.0093. {3. 2. Department of earth sciences, Zhongshan university, Guangzhou 5102.5, {3. 3. Guangdong Pharmaceutical College, Guangzhou 5102.4, {3. Department of earth sciences Nanjing University Nanjing 210093 China Department of earth sciences Zhongshan University Guangzhou 510275 China Guangdong Pharmaceutical College Guangzhou 510244 China

VERY little is known about the roles of microorganisms in the metallogeny of weathering crust REE deposits, although there has been much literature on REE behavior in weathering conditions. The present note deals with the microorganisms in 4 weathering profiles of an REE deposit and their roles in migration and accumulation of REE in weathering conditions. 1 Cultivation and identification of microorganisms Under strict sterilization, samples were collected from various parts of 4 weathering profiles of granites in a weathering crust REE deposit in South china. The samples were then cultivated for microorganisms with ordinary agars as culture media and then the cultivated microorganisms were dyed and identifiedunder a microscope. The sampled positions and cultivated numbers of microbial colonies are shown

关键词： microbial metallogeny weathering crust REE deposit South china.

Spatial heterogeneity of the driving forces of cropland change in china

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Science china earth {2. 2005年第12期48卷 2231-2240页

作者： LIU Xuhua1,2. WANG Jinfeng1, LIU Mingliang4,1 & MENG Bin1,2.3.1. Institute of Geographic sciences and Natural Resources Research, Chinese Academy of sciences, Beijing 100101, china 2. Graduate {3. of the Chinese Academy of sciences, Beijing 10003., china 3. College of Arts and sciences of Beijing Union university, Beijing 100083. china 4. {3. of Forestry and Wildlife sciences, Auburn university, Auburn, Alabama, AL3.849, USA Institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences Beijing China Graduate school of the Chinese Academy of sciences Beijing China school of Forestry and Wildlife sciences Auburn University Auburn Alabama USA College of Arts and sciences of Beijing Union university Beijing China

By using digital satellite remote sensing data acquired in 1987―1989 and 1999―2.00 and GIS combined with the natural and socio-economic data, this paper drew an integrated zonation of the cropland change and its driving forces in china. The results indicated that the cropland change in the study period was constrained by geographical factors and driven by cli-mate change as well as socio-economic system. Moreover, the regional differences of the drivers for cropland change were significant. In the midwest of china, natural condition changes and geographical background were the main constraints and drivers, while in Eastern china, social and economic changes and economic policies were the main driving forces. The cropland loss was nationwide. The dominant factors to cause this decrease included buildup of developing area to attract foreign capital and technologies, changes of industry structure due to urban in-fluence, the change of employment notions thanks to living standard improvement, rapid ur-banization due to the expansion of cities and towns, the diminished farming net income partly because of the global warming effects, and the rapid economic growth stimulated by the con-venient transportation system. These factors interact and interdepend with each other to cause the cropland loss in china recently. The reasons for the increase of cropland were primarily the cultivation and deforestation by the farmers who want to increase income. This study on the mechnism of LUCC relied on the cropland change integrated classification considering the natural or human factors both inside and outside the region, which provides a new approach to study the integrated regionalization and LUCC mechanism.

关键词： land use change, driving force, integrated classification, spatial statistics, cropland, china.

Analysis for twinning and slip in face-centered cubic crystals under axisymmetric co-deformation

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Science china(Technological sciences) 2006年第5期49卷 521-536页

作者： CHEN Zhiyong1,2. CAI Hongnian1, ZHANG Xinming2. WANG Fuchi1 & TAN Chengwen1,3.1. school of Material Science and Engineering, Beijing Institute of Technology, Beijing 100081, {2. 2. school of Material Science and Engineering, Central South {3., Changsha 410083. {2. 3. school of Material Science and Engineering, Beijing {3. of Aeronautics and Astronautics, Beijing 100083. {2. school of Material Science and Engineering Beijing Institute of Technology Beijing China school of Material Science and Engineering Central South University Changsha China school of Material Science and Engineering Beijing University of Aeronautics and Astronautics Beijing China

The maximum work principle of Bishop-Hill was developed to analyze the axisymmetric co-deformation in face-centered cubic crystals (f.c.c.) for twinning on {111} 112.and slip on {111} 110 systems. The influence of ξ , the ratio of critical re- solved shear stress for twinning to slip, on the yield stress states and corresponding active slip or/and twinning systems for orientations in the standard stereographic triangle of cubic crystal was investigated systematically. The Taylor factors and the anisotropy of yield strength for three important orientations [100], [110] and [111] in orientation space were analyzed. It is found that the yield strength asymmetry for the case of axisymmetric de- formation of tension and compression can be explained based on the microscopic theory of crystal plasticity. The concept of orientation factor for twinning ability was proposed and the deformation mechanism map in the orientation space was established for the case of axisymmetric deformation. The deformation texture formation and development of f.c.c. crystals with low stacking fault energy for axisymmetric tension can be explained qualita- tively on the basis of analyzed results.

关键词： twinning slip face-centered cubic crystals axisymmetric co-deformation Bishop-Hill maximum work principle yield strength anisotropy