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Relationships between bacterial-algal proliferating and mass extinction in the Late Devonian Frasnian-Famennian transition:Enlightening from carbon isotopes and molecular fossils

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science china Earth sciences 2005年第10期48卷 1656-1665页

作者： GONG Yiming1,2, XU Ran1, TANG Zhongdao1, SI Yuanlan3.& LI Baohua4 1. Faculty of Earth science and State Key Laboratory of Geological Processes and Mineral Resources, china university of Geosciences, wuhan 430074, china 2. Institute of Resources & Environments, Henan Polytechnic university, Jiaozuo 454003. china 3. department of computer science, south-central university for nationalities, wuhan 430074, china 4. Laboratory of Marine Geology, Tongji university, Shanghai 200092, china china university of Geosciences Henan Polytechnic university south-central university for {3. Tongji university

Studies show positive shifts of inorganic and organic carbon isotope values (δ 13.carb and δ 13.kerogen) from +0.43.(‰ V-PDB) to +3.54 (‰ V-PDB) and from ?29.3. (‰ V-PDB) to ?24.14 (‰ V-PDB), respectively, B* (Ba* = Ba/ (Al2O3.X 15%)) values from 0.015 to 0.144, TOC values from 0.02% to 0.21%, V/Cr values from 0.3.to 2.0, Sr/Ba values from 3.20 to 49.50 in the Late Devonian Frasnian Upper rhenana zone to the top linguiformis zone of the Yangdi sec-tion deposited in carbonate slope facies of Guilin, Guangxi, south china, which indicates that biomass, productivity, organic carbon burial and salinity increase and that oxygenation near the boundary between sediments and waters decreases from the Late Devonian Frasnian Upper rhenana zone to the top linguiformis zone. Abundance of molecular fossils increases and normal alkanes, isoprenoid hydrocarbon, terpanes and steranes are dominated from the Late Devonian Frasnian to the bottom of Famennian, which shows that the predecessors of molecular fossils of the Frasnian-Famennian (F-F) transition are dominated by marine phytoplankton, zooplankton and benthic bacteria with no photosynthesis. Therefore, it is considered that the F-F transitional mass extinction with a multistage, selection and global synchronizing was caused by bacte-rial-algal proliferating, continuing deterioration of the shallow marine ecoenvironment of the mid-dle-lower latitudes. A simple cause and effect chain can be expressed as: appearance of seed plants and multi-storied forests → enhanced chemical and biochemical weathering and pe-dogenesis → wide development of soils → increasing riverine nutrient fluxes in epicontinental sea → from superoligotrophic to eutrophic in epicontinental sea → proliferating of marine phyto-plankton and zooplankton → frequent red tide and anoxia → mass extinction of shallow marine organisms in the middle-lower latitudes. It is worth notice that the factor drawdown of atmos-pheric Pco2, climatic cooling and sea level falling c

关键词： mass extinction, bacteria-algae, carbon isotopes, molecular fossils, biodiversity, Late Devonian, Guangxi, south china.

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A quasi-physical algorithm for solving the linear separation problem in n-dimensional space

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Journal of central south university of Technology 2001年第4期8卷 272-277页

作者： HUANG Jia yuan (College of computer science, Huazhong university of science and Technology, wuhan 430074, china) College of computer science Huazhong University of Science and Technology Wuhan China

A quasi physical algorithm was proposed for solving the linear separation problem of point set in n dimensional *** original idea of the quasi physical algorithm is to find an equivalent physical world for the primitive mathematical problem and to observe the vivid images of the motion of matter in it so as to be inspired to obtain an algorithm for solving the mathematical problem. In this work, the electrostatics with two kinds of matter is found to be the equivalent physical world. As a result,the proposed algorithm is evidently more efficient and robust than the famous LMS algorithm and ETL algorithm. The efficiency of the quasi physical algorithm is about 10-50 times of the LMS algorithm’s for representative instances. A typical Boolean valued instance shows that it is hard for ETL algorithm but very easy for the quasi physical *** this instance, point set A and B is {000, 010, 011, 111} and {001,100}, respectively.

关键词： linear separation problem neural network algorithm quasi-physical method electrostatics

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An architecture for mobile database management system

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Journal of university of science and Technology Beijing 2002年第2期9卷 156-160页

作者： Dong Li and Yucai Feng computer School, Huazhong university of science and Technology,{3., china computer School Huazhong University of Science and Technology Wuhan 430074 China

In order to design a new kind of mobile database management system (DBMS)more suitable for mobile computing than the existent DBMS, the essence of database systems in mobilecomputing is analyzed. An opinion is introduced that the mobile database is a kind of dynamicdistributed database, and the concept of virtual servers to translate the clients' mobility to theservers' mobility is proposed. Based on these opinions, a kind of architecture of mobile DBMS, whichis of versatility, is presented. The architecture is composed of a virtual server and a local DBMS,the virtual server is the kernel of the architecture and its functions are described. Eventually,the server kernel of a mobile DBMS prototype is illustrated.

关键词： mobile database dynamic distributed database DBMS architecture virtual server data region

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A New Clustering Algorithm for Categorical Attributes

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International Journal of Minerals,Metallurgy and Materials 2000年第4期14卷 318-322页

作者： Songfeng Lu, Zhengding Lu (College of computer science and Technology, Huazhong university of science and Technology, wuhan 430074, china) College of computer science and Technology Huazhong University of Science and Technology Wuhan 430074 China

In traditional data clustering, similarity of a cluster of objects is measured by distance between objects. Such measures are not appropriate for categorical data. A new clustering criterion to determine the similarity between points with categorical attributes is pre- sented. Furthermore, a new clustering algorithm for categorical attributes is addressed. A single scan of the dataset yields a good clus- tering, and more additional passes can be used to improve the quality further.

关键词： data mining clustering similarity Information

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Convergence analysis for general linear methods applied to stiff delay differential equations

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Progress in Natural science:Materials International 2002年第6期12卷 16-22页

作者： ZHANG Chengjian(department of Mathematics, Huazhong university of science and Technology,{3., china) Huazhong Univ Sci & Technol Dept Math Wuhan 430074 Peoples R China

For Runge-Kutta methods applied to stiff delay differential equations (DDEs), the concept of D-convergence was proposed, which is an extension to that of B-convergence in ordinary differential equations (ODEs) . In this paper, D-convergence of general linear methods is discussed and the previous related results are improved. Some order results to determine D-convergence of the methods are obtained.

关键词： D-convergence general linear methods stiff delay differential equations.

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EXISTENCE OF GLOBAL SMOOTH SOLUTION TO INITIAL BOUNDARY VALUE PROBLEM FOR A VISCOELASTIC MODEL WITH RELAXATION

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Acta Mathematica Scientia 2004年第2期24卷 265-274页

作者：阮立志朱长江 LaboratoryofNonlinearAnalysis Dept.ofMath.CentralChinaNormalUniversityWuhan430079China

This paper is concerned with the initial boundary value problem for a viscoelastic model with relaxation. Under the only assumption that the C^0-norm of the initial data is small, without smallness hypothesis for the C^1-norm, the existence of the global smooth solution to the corresponding initial boundary value problem is proved. The analysis is based on some a priori estimates obtained by the 'maximum principle' of first-order quasilinear hyperbolic system.

关键词： Viscoelastic model relaxation a priori estimates maximum principle

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On the new results of global attractive set and positive invariant set of the Lorenz chaotic system and the applications to chaos control and synchronization

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science in china(Series F) 2005年第3期48卷 304-321页

作者： LIAO Xiaoxin 1, 2, 3., FU Yuli 4 & XIE Shengli 4 1. department of Control science & Control Engineering, Huazhong university of science & Technology, wuhan 430074, china 2. School of Automation, wuhan university of science & Technology, wuhan 43.070, china 3. School of Information, central south university of Economy, Politics and Law, wuhan 43.064, china 4. School of Electronics & Information Engineering, south china university of Technology, Guangzhou 510640, china Correspondence should be addressed to Liao Xiaoxin (email: xiaoxin_liao@***) department of Control science & Control Engineering Huazhong University of Science & Technology Wuhan 430074 China

Constructing a family of generalized Lyapunov functions, a new method is proposed to obtain new global attractive set and positive invariant set of the Lorenz chaotic system. The method we proposed greatly simplifies the complex proofs of the two famous estimations presented by the Russian scholar Leonov. Our uniform formula can derive a series of the new estimations. Employing the idea of intersection in set theory, we extract a new Leonov formula-like estimation from the family of the estimations. With our method and the new estimation, one can confirm that there are no equilibrium, periodic solutions, almost periodic motions, wandering motions or other chaotic attractors outside the global attractive set. The Lorenz butterfly-like singular attractors are located in the global attractive set only. This result is applied to the chaos control and chaos synchronization. Some feedback control laws are obtained to guarantee that all the trajectories of the Lorenz systems track a periodic solution, or globally stabilize an unstable (or locally stable but not globally asymptotically stable) equilibrium. Further, some new global exponential chaos synchronization results are presented. Our new method and the new results are expected to be applied in real secure communication systems.

关键词： Lorenz chaotic system global attractive set positive invariant set globally exponential tracking globally exponential synchronization.

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A low frequency piezoelectric power harvester using a spiral-shaped bimorph

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science china(Physics,Mechanics & Astronomy) 2006年第6期49卷 649-659页

作者： HU Yuantai1,2,HU Hongping2 & YANG Jiashi3.1. Institute of Mechanics and Sensing Technology,central south university,Changsha 410083.{3. 2. department of Mechanics,Huazhong university of science and Technology,wuhan 430074,{3. 3. department of Engineering Mechanics,university of Nebraska,Lincoln,NE 68588-0526,USA Institute of Mechanics and Sensing Technology Central South University Changsha 410083 China

We propose a spiral-shaped piezoelectric bimorph power harvester operating with coupled flexural and extensional vibration modes for applications to low frequency energy sources. A theoretical analysis is performed and the computational results show that the spiral structure has relatively low operating frequency compared to beam power harvesters of the same size. It is found that to optimize the performance of a piezoelectric spiral-shaped harvester careful design is needed.

关键词： spiral-shaped bimorph,piezoelectric harvester,power density.

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D-CONVERGENCE AND STABILITY OF A CLASS OF LINEAR MULTISTEP METHODS FOR NONLINEAR DDES

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Journal of Computational Mathematics 2000年第2期18卷 199-206页

作者： Cheng-jian Zhang Xiao-xin Liao (department of Mathematics, Huazhong university of science and Technology,{3., china) 华中科技大学湖北武汉 430074

Presents information on a study which dealt with the error behavior and the stability analysis of a class of linear multistep methods with the Lagrangian interpolation as applied to the nonlinear delay differential eq... 详细信息

关键词： D-convergence stability multistep methods nonlinear DDEs

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LAMINATED PIEZOELECTRIC PLATE FOR ACTIVE UNDERWATER ACOUSTIC CONTROL

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Acta Mechanica Solida Sinica 2001年第4期14卷 306-311页

作者： Zhao Hanzhong (department of Mechanics,Huazhong university of science and Technology,{3. 430074,china) department of Mechanics Huazhong Univ. of Sci. and Technol. Wuhan 430074 China

The pressure reflected from a bi-laminated piezoelectric plate hasbeen determined using the Thomson-Haskell matrix method. The plate iscomposed of a piezoelectric layer with grounded vacuum and An elasticlayer in contact with the fluid. An incident plane wave in the fluidmedium strikes the plate at dif- Ferent angles. The required electricpotential across the piezoelectric layer to cancel the reflectionfrom the Fluid/elastic boundary has been determined for thepiezoelectric material PZT-5 at various thickness parame- Ters andincident frequencies.

关键词： underwater acoustic control laminated piezoelectric plate acousticscattering acoustic radiation

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