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Research progress in studies on the coalbed gas geochemistry

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Progress in Natural Science:Materials International 2006年第3期16卷 215-220页

作者： TAO Mingxin (College of Resources Sciences & Technology, Beijing Normal university, Beijing 100875, china Key Laboratory of Gas Geochemistry, Institute of Geology and Geophysics, Chinese Academy of Sciences, Lanzhou 730000, china) College of Resources Sciences & Technology Beijing Normal University Beijing 100875 China Key Laboratory of Gas Geo- chemistry Institute of Geology and Geophysics Chinese Academy of Sciences Lanzhou 730000 China

The current situation of geochemical studies on coalbed gas is reviewed in this paper. Generally, coalbed gas is composi-tionally dominated by methane with δ13C1 values ranging approximately from - 80‰ to - 10‰. However, few isotopic studies have been carried out on other components of coalbed gas except for hydrogen and carbon dioxide, whose δDCH4 values available for utilization vary from - 333‰ to - 117‰, and δ13CCO2 values from - 29. 4‰ to + 18. 6.. Two major types of coalbed gas, thermogenic gas and secondary biogenic gas, have been identified, and there are also some other classification criteria. Compared with conventional natural gases, coalbed gas has a wide distribution range of δ13C1 and δ13CCO2 values, especially possessing some extremely heavy values. Current problems that remain unsolved in the coalbed gas geochemistry include the variation mechanism, controlling factors and application of carbon and hydrogen isotopes of methane, the relation between the values of δ13C1 and Ro, the systematic classification scheme and criterion of genetic types, and the application of the coalbed gas geochemistry in evaluating target districts of the coalbed gas exploration.

关键词： coalbed gas geochemistry isotopic composition genetic type novel resource.

Local well-posedness of lower regularity solutions for the incompressible viscoelastic fluid system

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Science china Mathematics 2010年第6期53卷 1521-1530页

作者： ZHAO WenJing1,& DU DaPeng2 1School of Mathematics Science,Fudan university,Shanghai 200433,china 2Institution of Mathematics,Fudan university,Shanghai 200433,china School of Mathematics Science Fudan University Institution of Mathematics Fudan University

In the present paper,the local well-posedness of the incompressible viscoelastic fluid system in the whole space is proved under the following assumption on the initial data:the deformation tensor is Hlder continuou... 详细信息

关键词： Oldroyd-B model characteristic direction Stokes kernel

THE STRUCTURE OF INVERTIBLE SUBSTITUTIONS ON A THREE-LETTER ALPHABET

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Analysis in Theory and Applications 2003年第4期19卷 365-382页

作者： Tan Bo Wen Zhixiong Zhang Yiping (wuhan university,china) wuhan university China

We study the structure of invertible substitutions on three-letter alphabet. We show that there exists a finite set S of invertible substitutions such that any invertible substitution can be written as I wσ 1σ 2…σ k,where I w is the inner automorphism associated with w, and σ j∈ S for 1≤j≤k. As a consequence,M is the matrix of an invertible substitution if and only if it is a finite product of non-negative elementary matrices.

关键词： invertible substitution indecomposable substitution combinatorics of words

FEASIBILITY　OF　THE　REICH　PROCEDURE　IN　THE　DECOMPOSITION　OF　PLANE　QUASICONFORMAL　MAPPINGS

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Chinese Annals of Mathematics,Series B 1995年第1期16卷 109-118页

作者： LAI WANCAI (Department of Applied Mathematics, Hua Qiao university, Qllanzhou 36.011, Fujian, china.) HUA QIAO UNIV DEPT APPL MATHQUANZHOU 362011PEOPLES R CHINA

In the decomposition problems, studied by Retch, of quasiconformal self mappings of the unit disc which keep the boundary points fixed, the construction of the first one requires the application of the Hahn-Banach theorem (so it is abstract) and it is only a variational decomposition (a small weight one), and that of the second one avoids the Hahn-Banach theorem and gets rid of the restriction to the variational decomposition. But the success of the second decomposition procedure (the Retch procedure) is guaranteed only when minimal maximal dilatation K(f) is sufficiently small. Therefore, it can not guarantee even a variational decomposition. Huang Xinzhong then proved that the inverse Reich procedure was successful for ally X(f). But the inverse Retch procedure is not so natural as the Retch procedure and the corresponding decomposition can not replace the first one. It is still an open problem whether the Reich procedure is successful for any X(f). The present paper gives an affirmative answer to this problem.

关键词： Quasiconformal mapping Decomposition Reich's procedure.

Efficient visualization techniques for high resolution remotely sensed data in a network environment

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Science china(Technological Sciences) 2008年第S1期51卷 124-134页

作者： WENG JingNong1,WU Lun2,HUANG Jian1,XIA YuBin3 & CAI Heng1 1 College of Software,Beihang university,Beijing 100083,china 2 Institute of Geographical Information System and Remote Sensing,Peking university,Beijing 100871,china 3 College of Computer,Beihang university,Beijing 100083,china College of Software Beihang University Institute of Geographical Information System and Remote Sensing Peking University

There are three major research hotspots in efficient visualization techniques of high resolution remotely sensed data in network environment: the data organiza-tion and access in disk storage,the image data stitching and fitting methods,and the network transfers and access. In this paper a new method of "Big File" organi-zation for improving the storage access efficiency of high resolution remote data is presented; a "virtual data source" concept is introduced to solve the stitching problem of remotely sensed data from different sources with different resolutions; a remotely sensed data access engine design based on ATL technique is discussed to process the network transfers and access of remotely sensed data. All these techniques have been adopted in a prototype of digital china named "chinaStar".

关键词： high resolution remotely sensed data spatial index pyramid model LOD Big File

Experimental measurement of growth patterns on fossil corals:Secular variation in ancient Earth-Sun distances

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Chinese Science Bulletin 2010年第35期55卷 4010-4017页

作者： ZHANG WeiJia1,3,4,LI ZhengBin2,3 & LEI Yang1 1 Department of Physics,Peking university,Beijing 100871,china 2 Department of Electrical Engineering and Computer Science,Peking university,Beijing 100871,china 3 State Key Laboratory of Advanced Optical Communication Systems & Networks,Peking university,Beijing 100871,china 4 Committee of Yuanpei Honors Program,Peking university,Beijing 100871,china Department of Physics Peking University Beijing 100871 China State Key Laboratory of Advanced Optical Communication Systems & Networks Peking University Beijing 100871 China Committee of Yuanpei Honors Program Peking University Beijing 100871 China Department of Electrical Engineering and Computer Science Peking University Beijing 100871 China

In recent years,much attention has been given to the increase in the Earth-Sun distance,with the modern rate reported as 5-15 m/cy on the basis of astronomical ***,traditional methods cannot measure the ancient leaving rates,so a myriad of research attempting to provide explanations were met with unmatched *** this paper we consider that the growth patterns on fossils could reflect the ancient Earth-Sun *** mechanical analysis of both the Earth-Sun and Earth-Moon systems,these patterns confirmed an increase in the Earth-Sun *** a large number of well-preserved specimens and new technology available,both the modern and ancient leaving rates could be measured with high precision,and it was found that the Earth has been leaving the Sun over the past 0.53 billion *** Earth's semi-major axis was 146.million kilometers at the beginning of the Phanerozoic Eon,equating to 97.6. of its current *** modern leaving rates are 5-14 m/cy,whereas the ancient rates were much *** results indicate a special expansion with an average expansion coefficient of 0.57H0 and deceleration in the form of Hubble *** the basis of experimental results,the Earth's semi-major axis could be represented by a simple formula that matches fossil measurements.

关键词：地球太阳古代距离生长模式实验石珊瑚量化

Determination of Lateral Extension of Hydrocarbon Concentration Sealing Caprocks by AVO Analysis

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Petroleum Science 2007年第4期4卷 17-22页

作者： Li Weilian Key Laboratory for Hydrocarbon Accumulation Mechanism Ministry of Education China University of Petroleum Beijing 102249 China

The caprock is one of the key factors for a reservoir, especially for a gas reservoir. Whether the caprocks can block off the gas is of significance for the accumulation and preservation of the gas reservoir. In this paper, we use the Amplitude versus offset （AVO） seismic technique to determine the lateral extension of the hydrocarbon concentration sealing caprocks. The essence of this technique is to detect the variations of the reservoir bed physical properties by monitoring the variations of the reflection coefficient of seismic waves upon the interfaces between different lithologies. Generally it is used to indicate hydrocarbon directly. For the hydrocarbon concentration sealing caprocks, the change of hydrocarbon concentration may cause the change of physical properties of the caprocks. Therefore it is possible to evaluate the hydrocarbon concentration sealing ability of the caprocks by AVO. This paper presents a case study using AVO to determine the lateral extension of the hydrocarbon concentration sealing caprocks. The result shows that this method is helpful for the exploration of the region.

关键词： AVO caprock hydrocarbon concentration sealing gas diffusion loss

Bcklund transformation, non-local symmetry and exact solutions for (2+1)-dimensional variable coefficient generalized KP equations

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Communications in Nonlinear Science and Numerical Simulation 2000年第1期5卷 31-35页

作者： Zhenya YAN Institute of Mathematical Science, Dalian university of Technology, Dalian 116.24, china e-mail: zhanghq@dlut. *** Institute of Mathematical Science Dalian University of Technology Dalian 116024 China

With the aid of MATHEMATICA, the idea of improved homogeneous balance method is extended to (2+1)-dimensional variable coefficients KP equation. As a result, Backlund transformation and non-local symmetry are found. Then via using the Backlund transformation, six families of exact solutions for (2+1)-dimensional variable coefficients KP equation are obtained, which contain new soliton-like solutions.

关键词： variable coefficient generalized KP equation Backlund transformation nonlocal symmetry exact solution soliton

Numerical calculation on temperature field of FGH95 alloy droplet during rapid solidification

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Journal of university of Science and Technology Beijing 2003年第3期10卷 51-54页

作者： Huanming Chen and Benfu Hu Materials Science and Engineering School, university of Science and Technology Beijing, Beijing 100083,china Physics and Electrical Information Engineering School, Ningxia university, Yinchuan 750021,china Univ Sci & Technol Beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China Ningxia Univ Phys & Elect Informat Engn Sch Yinchuan 750021 Peoples R China

The temperature field of FGH95 alloy droplet atomized by plasma rotatingelectrode processing (PREP) during solidification has been calculated through numerical analysisbased on equivalent sensible heat capacity method. And thus the relational curves among temperaturegradient of solid-liquid interface, moving velocity of solid-liquid interface and solid fractionduring solidification have been presented. The results indicate that the relation between averagetemperature gradient of solid-liquid interface and droplet size, and the relation between averagemoving velocity of solid-liquid interface and droplet size can be expressed during solidification.

关键词： FGH95 alloy droplet temperature field numerical calculation