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^(13)C NMR spectra of tectonic coals and the effects of stress on structural components

Science china Earth sciences 2005年第9期48卷 1418-1437页

作者： JU Yiwen1,2. JIANG Bo1, HOU Quanlin2. WANG Guiliang1 & NI Shanqin2.1. college of Mineral Resource and geosciences,{2. University of Mining and Technology, Xuzhou 2.1008,{2. 2. laboratory of computational geodynamics, college of geosciences, Graduate school of chinese academy of sciences, beijing 100049,{2. 1. college of Mineral Resource and geosciences China University of Mining and Technology 221008 Xuzhou China 2. laboratory of computational geodynamics College of Geosciences Graduate School of Chinese Academy of Sciences 100049 Beijing China

High-resolution 13C Nuclear Magnetic Resonance (NMR) spectra of different kinds of tectonic coals were obtained using the NMR (CP/MAS+TOSS) method. On the basis of this, after simulation synthesis and division of spectra, the relative contents of carbon functional groups were calculated. Combined with results of Ro, max, XRD testing and element analysis, stress effects on the composition of macromolecular structures in tectonic coals were studied further. The results showed that Ro, max was not only the important index for describing coal rank, but was also effective for estimating the stress effect of tectonic coals. Under tectonic stress ac- tion, Ro, max was the most direct indicator of the coal structure and chemical components. Changes in the stacking Lc of the coal basic structure unit (BSU) and La/Lc parameters could distinguish the temperature and stress effects on metamorphic-deformed environments, and re- flected the degree of structural deformation. Therefore, on the whole, Lc and La/Lc can be used to index of the degree of structural deformation of tectonic coals. In different metamorphic and de- formed environments, different kinds of tectonic coals are formed under structural stress. The changes in characteristics of the macromolecular structure and chemical composition are such that as the increase in structural deformation becomes stronger, from the brittle deformation coal to ductile deformation coal, the ratio of width at the half height of the aromatic carbon and ali- phatic carbon peaks (Hfa/Hfal ) was increased. As carbon aromaticity was raised further, carbon aliphaticity reduced obviously and different compositions of macromolecular structure appeared as a jump and wave pattern except for in wrinkle structure coal, which might result chiefly from stress effects on the macromolecular structure of different kinds of tectonic coals. The macro- moecular changes of wrinkle structure coal are reflected mainly on physical structure. In the metamorphi

关键词： tectonic coal, NMR, macromolecular structure, chemical component, stress effect.

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Stochastic dynamic model of SARS spreading

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chinese Science Bulletin 2003年第13期48卷 1287-1292页

作者： SHI Yaolin computational geodynamics {2. of Graduate school of chinese academy of sciences, beijing 100039, china (e-mail: shiyl@***) computational geodynamics {2. of Graduate school of chinese academy of sciences 100039 Beijing China.

Based upon the simulation of the stochastic process of infection, onset and spreading of each SARS patient, a system dynamic model of SRAS spreading is constructed. Data from Vietnam is taken as an example for Monte Carlo test. The preliminary results indicate that the time-dependent infection rate is the most important control factor for SARS spreading. The model can be applied to prediction of the course with fluctuations of the epidemics, if the previous history of the epidemics and the future infection rate under control measures are known.

关键词： SARS 非典型肺炎随机过程传染病模型疫情控制

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RADIAL BASIS FUNCTION INTERPOLATION IN SOBOLEV SPACES AND ITS APPLICATIONS

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Journal of computational Mathematics 2007年第2期25卷 201-210页

作者： Manping Zhang (school of Mathematical sciences,Fudan University,Shanghai 2.0433,{2. Institute of computational Mathematics,chinese academy of sciences,beijing 100080,{2. school of Mathematical sciences Fudan University Shanghai 200433 China Institute of computational Mathematics Chinese Academy of Sciences Beijing 100080 China

In this paper we study the method of interpolation by radial basis functions and give some error estimates in Sobolev space H^k（Ω）（k 〉 1）. With a special kind of radial basis function, we construct a basis in H^k（Ω） and derive a meshless method for solving elliptic partial differential equations. We also propose a method for computing the global data density.

关键词： Sobolev space Radial basis function Global data density Meshless method

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A tentative study for the prediction of the CME related geomagnetic storm intensity and its transit time

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Science china(Technological sciences) 2005年第6期48卷 648-668页

作者： ZHAO Xinhua1,2.& FENG Xueshang1,3 1. SIGMA Weather Group, Key laboratory of Space Weather, Center for Space Science and Applied Re-search, chinese {2. of sciences, beijing 100080, china 2. Graduate school of the chinese {2. of sciences, beijing 100039, china 3. school of Geophysics and Geoinformation Systems, china University of geosciences, beijing 100083, china 1. SIGMA Weather Group Key Laboratory of Space Weather Center for Space Science and Applied Research Chinese Academy of Sciences 100080 Beijing China 2. Graduate school of the chinese {2. of sciences 100039 Beijing China 3. school of Geophysics and Geoinformation Systems China University of Geosciences 100083 Beijing China

Using 80 CME-ICME events during 1997.1―2.02.9, based on the eruptive source locations of CMEs and solar magnetic field observation at the photosphere, a current sheet magnetic coordinate (CMC) system is established in order to study the propagation of CME and its geoeffectiveness. In context of this coordinate system, the effect of the eruptive source location and the form of heliospheric current sheet (HCS) at the eruptive time of CME on the geomagnetic storm intensity caused by CME and the CME’s transit time at the Earth is investigated in detail. Our preliminary conclusions are: 1) The geomagnetic disturbances caused by CMEs tend to have the so-called “same side-opposite side effect”, i.e. CMEs erupt from the same side of the HCS as the earth would be more likely to arrive at the earth and the geomagnetic disturbances associated with them tend to be of larger magnitude, while CMEs erupting from the opposite side would arrive at the earth with less probability and the corresponding geomagnetic disturbance magnitudes would be relatively weaker. 2. The angular separation between the earth and the HCS affect the corresponding disturbance intensity. That is, when our earth is located near the HCS, adverse space weather events occur most probably. 3) The erupting location of the CME and its nearby form of HCS will also affect its arrival time at the earth. According to these conclusions, in this context of CMC coordinate we arrive at new prediction method for estimating the geomagnetic storm intensity (Dstmin) caused by CMEs and their transit times. The application of the empirical model for 80 CME-ICME events shows that the relative error of Dst is within 30% for 59% events with Dstmin≤?50 nT, while the averaged absolute error of transit time is lower than 10 h for all events.

关键词： coronal mass ejections, current sheet magnetic coordinate system, geomagnetic storm intensity, transit time, prediction method.

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Algebraically explicit analytical solu-tions for the unsteady non-Newtonian swirling flow in an annular pipe

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Science china(Physics,Mechanics & Astronomy) 2006年第4期49卷 396-400页

作者： CAI Ruixian1 & GOU Chenhua1,2.1. Institute of Engineering Thermophysics, chinese academy of {2., beijing 100080, china 2. Graduate school, chinese academy of {2., beijing 100080, china 1. Institute of Engineering Thermophysics Chinese Academy of Sciences Beijing 100080 China 2. Graduate school Chinese Academy of Sciences Beijing 100080 China

This paper presents two algebraically explicit analytical solutions for the incompressible unsteady rotational flow of Oldroyd-B type in an annular pipe. The first solution is derived with the common method of separation of variables. The second one is deduced with the method of separation of variables with addition developed in recent years. The first analytical solution is of clear physical meaning and both of them are fairly simple and valuable for the newly developing computational fluid dynamics. They can be used as the benchmark solutions to verify the applicability of the existing numerical computational methods and to inspire new differencing schemes, grid generation ways, etc. Moreover, a steady solution for the generalized second grade rheologic fluid flow is also presented. The correctness of these solutions can be easily proven by substituting them into the original governing equation.

关键词： analytical solution, Oldroyd-B type fluid, swirling flow, non-Newtonian.

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Explicit analytical solutions of the anisotropic Brinkman model for the natural convection in porous media(Ⅱ)

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Science china(Physics,Mechanics & Astronomy) 2005年第4期48卷 422-430页

作者： CAI Ruixian1, GOU Chenhua1, 2.& ZHANG Na1 1. Institute of Engineering Thermophysics, chinese academy of {2., beijing 100080, china 2. Graduate school, chinese academy of {2., beijing 100080, china 1. Institute of Engineering Thermophysics Chinese Academy of Sciences 100080 Beijing China 2. Graduate school Chinese Academy of Sciences 10080 Beijing China

Some algebraically explicit analytical solutions are derived for the anisotropic Brinkman model―an improved Darcy model―describing the natural convection in porous media. Besides their important theoretical meaning (for example, in analyzing the non-Darcy and anisotropic effects on the convection), such analytical solutions can be the benchmark solutions that can promote the development of computational heat and mass transfer. Some solutions considering the anisotropic effect of permeability have been given previously by the authors, and this paper gives solutions including the anisotropic effect of thermal conductivity and the effect of heat sources.

关键词： explicit analytical solution, porous medium, natural convection, Brinkman model, anisotropic.

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Microcosmic analysis of ductile shearing zones of coal seams of brittle deformation domain in superficial lithosphere

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Science china Earth sciences 2004年第5期47卷 393-404页

作者： JU Yiwen1,2. WANG Guiliang2. JIANG Bo2.& HOU Quanlin1 1. Graduate school, chinese {2. of sciences, beijing 100039, china 2. college of Mineral Resources and geosciences, china University of Mining & Technology, Xuzhou 2.1008, china chinese Acad Sci Grad Sch Beijing 100039 Peoples R China china Univ Min & Technol Coll Mineral Resources & Geosci Xuzhou 221008 Peoples R China

The ductile shearing zones of coal seams in a brittle deformation domain in super-ficial lithosphere are put forward based on the study on bedding shearing and ductile rheology of coal seams. The macrocosmic and microcosmic characteristics include wrinkle fold, mymonitized zones and ductile planar structure of coal seams, etc., while the microcosmic characteristics may also include different optic-axis fabrics and the anisotropy of vitrinite reflectance as well as the change of chemical structure and organic geochemistry components. The forming mechanism is analyzed and the strain environment of ductile shearing zones of coal seams discussed. The result indicates that, in the superficial brittle deformation domain, the coal seams are easy to be deformed, resulting in not only brittle deformation but also ductile shearing deformation under the action of force. Because of simple shearing stress, the interlayer gliding or ductile rheology may take place between coal seams and wall rocks. Therefore, many ductile shearing zones come into being in superficial lithosphere (<5 km). The research on ductile shearing zone of brittle de-formation domain in superficial lithosphere is significant not only theoretically for the study of ductile shearing and ductile rheology of the lithosphere but also practically for the structural movement of coal seams, the formation and accumulation of coal-bed methane, and the preven-tion and harness of gas burst in coal mine.

关键词： brittle deformation domain, interlayer gliding, ductile rheology, ductile shearing zones of coal seams, coal mymonite, vitrinite reflectance anisotropy.

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ON THE CENTRAL RELAXING SCHEME Ⅱ: SYSTEMS OF HYPERBOLIC CONSERVATION LAWS

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Journal of computational Mathematics 2001年第6期19卷 571-582页

作者： Hua-zhong Tang (school of Mathematical sciences, Peking University, {2. 100871, china) (LSEC,ICMSEC academy of Mathematics and Systems sciences, chinese academy of sciences, {2. 100080, china) school of Mathematical sciences Peking University Beijing 100871 China

This paper continues to study the central relaxing schemes for system of hyperbolic conservation laws, based on the local relaxation approximation. Two classes of relaxing systems with stiff source term are introduced to approximate system of conservation laws in curvilinear coordinates. Based on them, the semi-implicit relaxing schemes are con- structed as in [6, 12. without using any linear or nonlinear Riemann solvers. Numerical experiments for one-dimensional and two-dimensional problems are presented to demon- strate the performance and resolution of the current schemes.

关键词： Hyperbolic conservation laws The relaxing system The central relaxing schemes The Euler equations.

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CONVERGENCE OF VORTEX METHODS FOR 3-D EULER EQUATIONS

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Journal of computational Mathematics 2000年第3期18卷 239-250页

作者： Jia-fu Lin (Institute of System Science, academy of Mathematics and System sciences, {2. academy of sciences, beijing, 100080, china school of Mathematical sciences, Peking University, beijing 100871, china) 中科院系统科学所北京 100080

Presents a study on the convergence of vortex methods for the three-dimensional Euler equations in bounded domains. Related studies on the convergence of vortex methods; Formulation of vortex methods; Convergence for ... 详细信息

关键词： Euler equations vortex methods convergence initial-boundary value problem

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High-sensitivity photovoltage based on the interfacial photoelectric effect in the SrTiO_(3-δ)/Si heterojunction

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Science china(Physics,Mechanics & Astronomy) 2010年第11期53卷 2080-2083页

作者： WEN Juan 1,GUO HaiZhong 1,XING Jie 2.Lü HuiBin 1,JIN Kui-Juan 1,HE Meng 1 & YANG GuoZhen 1 1 beijing National laboratory for Condensed Matter Physics,Institute of Physics,{2. academy of sciences,beijing 100190,china 2.school of Materials sciences and Technology,china University of geosciences,beijing 100083,china 1. beijing National laboratory for Condensed Matter Physics Institute of Physics Chinese Academy of Sciences Beijing 100190 China2. School of Materials Sciences and Technology China University of Geosciences Beijing 100083 China

A high sensitivity photovoltaic effect has been observed in a heterojunction composed of n-type wide bandgap oxide SrTiO 3-δ and p-type Si fabricated by laser molecular beam *** responsivity of open-circuit photovoltage can reach 10 4 V/W without any amplification under zero bias for the wavelength range from visible to near infrared light in nW-μW *** attribute the high performance of the photovoltage responsivity to the interfacial photoelectric effects in the SrTiO 3-δ /Si *** the experimental results,some ideas can be generalized to improve photovoltaic efficiency and develop high sensitivity photodetectors with wide bandgap oxide materials and Si.

关键词： SrTiO 3-δ/Si heterojunction interfacial photoelectric effect photovoltage

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