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Applied Mathematics(A Journal of Chinese Universities) 2008年第3期23卷 256-264页

作者： LUO Jian-hua College of Science,central south university of forestry and technology,Changsha 410004,china Institute of Statistics,central south university of forestry and technology,Changsha 410004,china. College of Science Central South University of Forestry and Technology Changsha 410004 China Institute of Statistics Central South University of Forestry and Technology Changsha 410004 China

In this paper, a new risk model is studied in which the rate of premium income is regarded as a random variable, the arrival of insurance policies is a Poisson process and the process of claim occurring is p-thinning process. The integral representations of the survival probability are gotten. The explicit formula of the survival probability on the infinite interval is obtained in the special casc cxponential *** Lundberg inequality and the common formula of the ruin probability are gotten in terms of some techniques from martingale theory.

关键词： risk model thinning process survival probability martingale ruin probability integral representation

MASS TRANSFER TO LIQUID-LIQUID INTERFACE

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Acta Metallurgica Sinica(English Letters) 1996年第2期9卷 151-156页

作者： LI Xinhai YIN Zhoulan(central-south university of technology,Changsha 410083,china) central-south Univ of technology Changsha China

Experiments have been done on mass transfer to a liquid-liquid interface on which inert gas bubbles are *** simulate the pyrometallurgy system of melten slag-metal(or matte),aqueous solution-mercury(or zinc amalgam) system was *** mass transfer coefficients of indicator ions as a function of bubble parameters have been *** experimental results show satisfactory agreement with the mass transfer model proposed Previously.

关键词： mass transfer gas bubble liquid-liquid interface

Ti/Al_2O_3 Functionally Gradient Material Prepared by the Explosive Compaction/SHS Process

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Journal of Materials Science & technology 1999年第3期15卷 271-275页

作者： Yimin LI(Powder Metallurgy Research Institute, central-south university of technology, Changsha 410083, china)Ziqiao ZHENG(Department of Materials Science and Engineering, central-south university of technology, Changsha 410083, china) Cent S Univ Technol Powder Met Res Inst Changsha 410083 Peoples R China Cent S Univ Technol Dept Mat Sci & Engn Changsha 410083 Peoples R China

Ti1Al2O3 Functionally Gradient Material (FGM) was prepared by an explosive compaction/SHS process. Ten sheets of the compounding powder were laminated and pressed to get a green body of FGM. It was then compacted explosively By burying the explosive compaction body into a stoichiometric Al/TiO2 mixture and igniting the combustion of the stoichiometric Al/TiO2 mixture, the SHS reaction of the explosive compaction body was initiated by the heat released from the combustion of the stoichiometric Al/TiO2 mixture. In this way, Ti/Al2O3 FGM was synthesized. The adiabatic temperatures of each gradient layer were calculated when the preheating temperatures were 298 K and 1173 K, respectively The microstructure, composition and properties of Ti/Al2O3 FGM and the reaction mechanism of each gradient layer were studied. It was found that Ti/Al2O3 FGM prepared by the explosive compaction/SHS process had a high density and a high microhardness. Its structure, composition and properties showed apparent gradient distribution. The structure of the standard stoichiometric ratio gradient layer of FGM was a network structure. Its reaction mode could be described as follows: Al powder melted first, then the molten Al penetrated into the TiO2 zone and reacted with TiO2, and big pores were left in the original positions of Al powder. The reaction of gradient layers with the addition of Al3O3 as diluents was similar to that of the standard stoichiometric ratio gradient layer, so were their structure and composition. However, the reaction of gradient layers with the addition of Ti as diluents was more complex and the composition deviated slightly from the designed one

关键词： Al SHS Ti/Al2O3 Functionally Gradient Material Prepared by the Explosive Compaction/SHS Process

Number of zero point for a polynomial in real field

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Chinese Science Bulletin 1997年第11期42卷 886-890页

作者： LIN Liang and LIU Yirong1. Guilin Institute of technology, Guilin 541004, china 2. central south university of technology, Changsha 410083, china Guilin Institute of technology Guilin 541004 China

IT is well known that for any real coefficient polynomial f(x) of degree n,how to determineits number of real zero points is a very important problem in theory of polynomial,as well as inapplications in mathematics,mechanics,physics and other *** way to solve thisproblem by using Euclidean mutual division as pointed out by Sturm is not simple and conve-nient for us to use the theoretic analyses for the above problem because the relation

关键词： polynomial real zero point coefficients.

Landscape ecological assessment and eco-tourism development in the south Dongting Lake Wetland, china

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Journal of Environmental Sciences 2003年第2期15卷 271-278页

作者： HE Ping 1,2, WANG Bao-zhong 1,3 (1.central south forestry university, Zhuzhou 412006, china 2.china International Engineering Consulting Corporation, Beijing 100044, china 3.Nanjing university, Nanjing 210093, china central south forestry university Zhuzhou 412006

As an important resource and the living environment of mankind, wetland has become gradually a highlight, strongly concerned and intensively studied by scientists and sociologists. The governments in the world and the whole society have been paying more and more attention on it. The Dongting Lake of china is regarded as an internationally important wetland. For a rational development and protection of the wetland, an investigation and studied on its resources and its value to tourism in the south Dongting Lake was conducted, to create an assessment system of the ecological landscapes, and to evaluate qualitatively and quantitatively the value of wetland landscape to the eco-tourism. The results showed that the scenic value of the south Dongting Lake Wetland satisfied the criterion of AAAA grade of china national scenic attraction. The eco-tourism value of the landscape cultures in the south Dongting Lake Wetland was discussed with emphasis. It were formulated that a principle and frame of sustainable exploitation of the wetland landscapes and it was proposed as well that establishing a Wetland Park and developing eco-tourism in the south Dongting Lake. Wetland is a fragile ecosystem with low resistance to the impact of the exploitation. Thus, we must pay intensively attention to the influence of exploitation on the landscape, take the ecological risk in account to employ a right countermeasure and avoid the negative affection.

关键词： south Dongting Lake wetland landscape eco-tourism Wetland Park ecological assessment

Microwave peak absorption frequency of liquid

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Science china(Physics,Mechanics & Astronomy) 2008年第9期51卷 1254-1263页

作者： HAN GuangZe1 & CHEN MingDong2 1 Department of Physics,south china university of technology,Guangzhou 510640,china 2 Guangzhou Auto College,south china university of technology,Guangzhou 510800,china 1. Department of Physics South China University of Technology Guangzhou 510640 China 2. Guangzhou Auto College South China University of Technology Guangzhou 510800 China

Microwave-assisted extraction is a new effective method which has practical ap-plications in many fields. Microwave heating is one of its physical mechanisms,and it also has the characteristic of selectivity. When the applied microwave fre-quency equals a certain absorption frequency of the material (or specific compo-nent),the material will intensively absorb microwave energy. This is also known as resonant absorption,and the frequency is called the peak absorption frequency which depends on the physical structure of the material. In this work,dynamic hy-drogen bond energy was included in molecular activation energy; with the liquid cell model,the expression of interaction energy between dipolar molecules was derived. The rotational relaxation time was gotten from the Eyring viscosity formula. Then based on the relationship between dielectric dissipation coefficient and re-laxation time,the expression of microwave peak absorption frequency as a func-tion of the material physical structure,rotational inertia and electrical dipole mo-ment of molecules was established. These theoretical formulas were applied to water and benzene,and the calculated results agree fairly well with the experi-mental data. This work can not only deepen the study of the interaction between microwave and material,but also provide a possible guide for the experiment of microwave-assisted extraction.

关键词： microwave-assisted extraction microwave heating relaxation time liquid viscosity peak absorption fre-quency

A Constitutive Model for Hot Pressing of Powders

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Journal of Materials Science & technology 1994年第5期10卷 374-380页

作者： Rongde GE (Dept. of Nonferrous Metallurgy, central south university of technology, Changsha, 410083, china) central south Univ of technology Changsha China

Based on an assumption that the effective pressure in hot pressing related to the applied pressure varies with the relative density of the compact in a power law form. a three-dimensional viscoelastic model that depicts the viscoelastic detormation behaviour of powder compacts in hot pressing has been developed. It has been shown by the experimental data that the proposed model in which the parameters are determined by means of nonlinear regression analysis can be used to describe the density-time relationship for the hot pressing of pure magnesium oxide and atomized iron powders and to estimate the end-point relative density of the compact.

关键词： A Constitutive Model for Hot Pressing of Powders

INFLUENCE OF HEAT TREATMENT ON THE MECHANICAL PROPERTIES OF RE Al-5.0Mg-0.6Cu ALLOY SHEET FOR AUTOMOBIL BODIES

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中国有色金属学会会刊：英文版 1993年第2期3卷 45-50页

作者： Sun,Xiaohua Wang,Mingpu central south university of technology,Changsha 410083,china

The influences of solution temperature,time in solution and quenching rate on the mechanical properties ofRE Al-5.0Mg-0,6Cu(wt.-%)alloy sheets for automobile bodies have been *** results show the re-quirements for heat treatments for the alloy sheets were not *** this alloy sheets are easy to produceon an industrial *** experiments indicate that there exists slight age hardening in the *** typicalmicrostructures of the alloy have also been analysed.

关键词： heat treatment rare earth Al-Mg-Cualloy mechanical properties

METALLOGENIC CHARACTERISTICS AND OREPROSPECTINGFUTURE OF PRECAMBRIAN GOLD DEPOSITSIN MUFUJIULING DISTRICT

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Journal of central south university 1996年第1期8卷 11-13页

作者： Wu Yanzhi(Department of Geology, central south university of technology,Changsha 410083, china) Department of Geology Central South University of Technology Changsha 410083 China

MufuJiuling district is an important placer gold producing land since the ancient time. In recent years, some primary gold deposits and mineralizations, e. g., Huangjindong and Tulongshan gold deposits, have been found. But the metallogenic conditions and regularities as well as the oreprospecting future remain to be recognized. Through the study on the metallogenic background and condition, the auriferous source bed and the mineralizing characteristics, three types of primary gold deposits are confirmed to be prospective in this district and some key problems about their prospecting and evaluating are put forward.

关键词： primary gold deposit PreCambrian age metallogenic marker