检索结果-南通市图书馆

A Feedback-Based Web Search Engine

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Wuhan University Journal of Natural Sciences 2004年第5期9卷 561-568页

作者： ZHANG Wei-feng 1,2,3 , XU Bao-wen 2,3,4 , ZHOU Xiao-yu 2,3,4 1. department of Computer Science and engineering, nanjing University of Posts and Telecommunications, nanjing 210003, Jiangsu, china 2. department of Computer Science and engineering, Southeast University, nanjing 210096, Jiangsu, china 3. Jiangsu institute of Software Quality, nanjing 210096 Jiangsu, china 4. The State Key Laboratory of Software engineering, Wuhan University, Wuhan 430072, Hubei, china department of Computer Science and engineering Nanjing University of Posts and Telecommunications . Nanjing 210003 Jiangsu China

Web search engines are very useful information service tools in the Internet. The current web search engines produce search results relating to the search terms and the actual information collected by them. Since the selections of the search results cannot affect the future ones, they may not cover most people’s interests. In this paper, feedback information produced by the user’s accessing lists will be represented by the rough set and can reconstruct the query string and influence the search results. And thus the search engines can provide self-adaptability. Key words WWW - search engine - query reconstruction - feedback CLC number TP 311. 135.4 Foundation item: Supported by the National Natural Science Fundation of china (60373066). National Grand Fundamental Research 973 Program of china (2002CB31200). Opening Foundation of State Key Laboratory of Software engineering in Wuhan University, Opening Foundation of Jiangsu Key Laboratory of Computer Information Processing technology in Soochow UniversityBiography: ZHANG Wei-feng (1975-), male, Ph.D. research direction: artificial intelligence, search engine, data mining, network language.

关键词： WWW search engine query reconstruction feedback

Effective capacity region of two-user opportunistic spectrum access

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Science china(Information Sciences) 2011年第9期54卷 1928-1937页

作者： XU YuHua,WANG JinLong & WU QiHui institute of communications engineering,PLA University of Science and technology,nanjing 210007,china 1. institute of communications engineering PLA University of Science and Technology Nanjing 210007 China

The effective capacity region of the two-user opportunistic spectrum access (OSA) system in Rayleigh fading environment is derived in this *** OSA is a contemporary research topic,little attention has been given to the capacity analysis under quality-of-service (QoS) ***,we use the effective capacity,which is a powerful tool to analyze the QoS requirements in wireless communication systems,to study the sustainable packet arrival rate of the secondary users while meeting statistical QoS *** derive the effective capacity region of the two-user OSA system and propose a method to obtain the capacity region *** addition,by combining the finite state channel model and the activity of the primary user,an extended finite state channel model for the two-user OSA system is also proposed.

关键词： cognitive radio opportunistic spectrum access effective capacity

A stepwise simulation approach to the chemical potential of fluids

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Chinese Journal of Chemistry 1994年第2期12卷 105-112页

作者： WU, Xiong-Wu SHI, Jundepartment of Chemical engineering, nanjing institute of Chemical technology, nanjing, Jiangsu 210009, chinaWANG, Wen-Chuandepartment of Chemical engineering, Beijing institute of Chemical technology, Beijing 100029, china 1department of Chemical engineering Nanjing Institute of Chemical Technology Nanjing Jiangsu 210009 China2Deportment of Chemical Engineering Beijing Institute of Chemical Technology Beijing 1000S9 China

A new approach to the computation of the chemical potential of fluids is presented. In this method the particle-insertion operation in the conventional test particle method is replaced by the growth of a specific particle. Application of the new technique to hard sphere and Lennard-Jones fluids shows that it is capable of providing reliable estimates of the chemical potential, even at high density where the conventional test particle methods are difficult to apply.

关键词： Chemical potential molecular simulation computation method hard sphere LennardJones fluids.

An eigenfunction expansion method for the elastodynamic response of an elastic solid with mixed boundary surfaces

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Progress in Natural Science:Materials International 2008年第9期18卷 1063-1068页

作者： Liguo Tang a,b,*, Jianchun Cheng c a department of Oceanography, Xiamen University, Xiamen 361005, china b Key Laboratory of Underwater Acoustic communication, and Marine Information technology, Ministry of Education, Xiamen University, Xiamen 361005, china c Laboratory of Modern Acoustics and institute of Acoustics, nanjing University, nanjing 210093, china department of Oceanography Xiamen University Xiamen 361005 China Key Laboratory of Underwater Acoustic communication and Marine Information technology Ministry of Education Xiamen University Xiamen 361005 China Laboratory of Modern Acoustics and institute of Acoustics Nanjing University Nanjing 210093 China

The method of eigenfunction expansion is one of the most elegant methods for solving elastodynamic problems. The solution obtained from it is more concise than that obtained from the integral transform technique. Traditional eigenfunction expansion method is used for the elastodynamic problems with displacement and traction boundary conditions. In this paper, the method is generalized to study the elastodynamic response of an elastic solid with mixed boundary surfaces, and the exact analytical solution is derived. The dynamic response of a finite-length solid aluminum cylinder with two mixed end boundaries is numerically evaluated. The result com- puted from the analytical solution agrees very well with that obtained from finite element method (FEM).

关键词： Eigenfunction expansion Elastodynamic response Mixed boundary

Theoretical Study on the Reaction Mechanism of F2+2HBr = 2HF+Br2

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Chinese Journal of Structural Chemistry 2005年第11期 110-115+12页

作者： SUN De-Shenga, b WANG Zun-Yaob YANG Chun-Shengb a (School of Chemistry and Chemical engineering, nanjing University of technology, Jiangsu, nanjing 210009, china) b(department of Chemical engineering, Yancheng institute of technology, Jiangsu, Yancheng 224003, china)

The gas phase reaction mechanism of F2 + 2HBr = 2HF + Br2 has been investigated by (U)MP2 at 6-311G** level, and a series of four-center and three-center transition states have been obtained. The reaction mechanism was achieved by comparing the activation energy of seven reaction paths, i.e. the dissociation energy of F2 is less than the activation energy of the bimolecular elementary reaction F2 + HBr → HF + BrF. Thus it is theoretically proved that the title reaction occurs more easily in the free radical reaction with three medium steps.

关键词： (U)MP2 transition state reaction mechanism free radical reaction.

A whisker-like carbon composite for the immobilization of laccase and its bioelectrochemistry

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Science china Chemistry 2010年第6期53卷 1332-1336页

作者： MA GuoXian1,2,ZHONG QingDong2 & LU TianHong3 1department of Chemical engineering,Shanghai institute of technology,Shanghai 200233,china 2School of Materials Science and engineering,Shanghai University,Shanghai 200072,china 3department of Chemistry,nanjing Normal University,nanjing 210097,china 1. department of Chemical engineering Shanghai Institute of Technology Shanghai 200233 China2. School of Materials Science and Engineering Shanghai University Shanghai 200072 China3. Department of Chemistry Nanjing Normal University Nanjing 210097 China

A novel mesoporous carbon/whisker-like carbon (MCWC) composite was used for the immobilization of laccase (Lac) and its bioelectrochemical behaviors were *** was confirmed by XPS that Lac was strongly adsorbed on the surface of the MCWC *** cyclic voltammetric results showed that the immobilized Lac underwent a direct quasi-reversible electrochemical *** value of the electron transfer rate constant ks was estimated to be 0.770 s-1,indicating a reasonably fast electron transfer between the immobilized Lac and the underlying *** surface concentration (I-) of Lac was estimated to be 2.730 × 10-12 mol/*** experimental results showed that the immobilized Lac displayed an appreciable electrocatalytic activity to the electrochemical reduction of *** properties could be attributed to the particular structure of loosely packed nanometer-scale carbon whiskers and the existence of a large amount of oxygen-containing *** immo- bilization method and the novel carrier (MCWC) may find new applications in fabricating the biocatalysts for biofuel cells.

关键词： laccase whisker-like carbon composite direct electrochemical reaction oxygen bioelectrochemistry

Bathynotus:A key trilobite taxon for global stratigraphic boundary correlation between Cambrian Series 2 and Cambrian Series 3

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Progress in Natural Science:Materials International 2009年第1期19卷 99-105页

作者： Jin Peng a,b,Yuanlong Zhao b,Jinliang Yuan c,Lu Yao b,Hong Yang b a department of Earth Sciences,nanjing University,nanjing 210093,china b College of Resource and Environmental engineering,Guizhou University(Caijiaguan Campus),Guiyang 550003,china c nanjing institute of Geology and Palaeontology,Chinese Academy of Sciences,nanjing 210008,china [a]department of Earth Sciences Nanjing University Nanjing 210093 China [b]College of Resource and Environmental Engineering Guizhou University (Caijiaguan Campus) Guiyang 550003 China [c]Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing 210008 China

The Cambrian trilobite Bathynotus is a special morphology of Redlichiid,which is characterized by a wider thorax axis and an 11th macropleural segment bearing a long,backwardly directed ***,its 12th and 13th pleural segments are narrow and they terminate at a fulcrum where they fuse together and to the posterior edge of the long macropleural *** genus is widely distributed,occurring in North America,Siberia,the Altay-Sayan fold belt of Russia,South china,the Tarim Basin of china,and *** occurs primarily in deposits of the upper part of the continental slope,at the transition between stable platform settings and subsiding margins of the late Early ***,we recognize three species of Bathynotus from china,including *** which is widespread around the *** six species of Bathynotus have been reported from Siberia and the Altay-Sayan fold belt area of Russia,data presented here suggest that only three of these species are *** exhibits a short geological range,with its first occurrence late in the unnamed Cambrian Series 2 and the last appearance datum of Bathynotus at the boundary of Cambrian Series 2 and Cambrian Series *** late appearance datum(LAD) of Bathynotus provides an important global stratigraphic marker of the boundary between Cambrian Series 2 and Cambrian Series 3.

关键词： Bathynotus Age Cambrian Series 2 Boundary Correlation

Thermal Insulation and Strength of Autoclaved Light Concrete

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Journal of Wuhan University of technology(Materials Science) 2011年第1期26卷 132-136页

作者：杨若冲吴智深 School of Transportation Southeast University institute of Urban engineering Science & technology Southeast University

The primary objective of this study was to develop an autoclaved light concrete （ALC） material with ultra-thermal insulation property and to investigate the relationship between its physical characteristics and mechanical properties. Through tests of dry bulk density and compressive strength, relationship of physical characteristics and mechanical properties of samples were studied, resulting in a material with ultra-thermal insulation property. Scanning electron microscope （SEM） and energy-dispersive X-ray spectroscopy （EDX） were applied to analyze the micro-morphology and elemental composition of samples. To identify the product phases, X-ray diffraction （XRD） was engaged. The test results showed that compressive strength and thermal coefficient were reduced with the increasing of aluminum powder within the mixtures. As a result the optimal thermal coefficient and compressive strength of samples were improved to 0.061 W/（m·k） and 1.2 MPa, respectively. SEM, EDX and XRD analyses showed that calcium silicate hydrate and tobermorite crystal were main resultant phases.

关键词： autoclaved light concrete ultra-thermal insulation microscopic appearance and phase analysis tobermorite crystal

Molecular dynamics simulations on the structures and properties of ε-CL-20-based PBXs ——Primary theoretical studies on HEDM formulation design

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Science china Chemistry 2007年第6期50卷 737-745页

作者： XU XiaoJuan1,2, XIAO JiJun1, HUANG Hui3, LI JinShan3 & XIAO HeMing1 1 department of Chemistry, nanjing University of Science and technology, nanjing 210094, china 2 department of Chemistry, Yancheng Teacher’s College, Yancheng 224002, china 3 institute of Chemical Materials, china Academy of engineering Physics, Mianyang 621900, china department of Chemistry Nanjing University of Science and TechnologyNanjing 210094China department of Chemistry Yancheng Teacher''s CollegeYancheng 224002China institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621900

Five polymer bonded explosives(PBXs)with the base explosive epsilon-CL-20(hexanitrohexaazaisowurtzi-tane),the most important high energy density compound(HEDC),and five polymer binders(Estane 5703,GAP,HTPB,PEG,and F_(2314))were *** dynamics(MD)method was employed to investigate their binding energies(E_(bind))4).By pair correlation function g(r)analyses,hydrogen bonds and vdw are found to be the main interactions between the two *** elasticity and isotropy of PBXs based epsilon-CL-20 can be obviously improved more than pure epsilon-CL-20 *** is not by changing the molecular structures of epsilon-CL-20 for each binder to affect the *** safety and energetic properties of these PBXs are mainly influenced by the thermal capability(C_p^(deg))and density(p)of binders,respectively.

关键词： high energy density material (HEDM), hexanitrohexaazaisowurtzitane (CL-20), polymer bonded explosives (PBXs), molecular dynamics (MD), compatibility, safety properties, mechanical properties, energetic properties