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 4.0}072, 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 3.1. 13..4.Foundation item: Supported by the National Natural Science Fundation of china (603.3.66). National Grand Fundamental Research 973.Program of china (2002CB3.200). 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

Some basic concepts and problems on the petrogenesis of intra-plate ocean island basalts

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Chinese Science Bulletin 2009年第22期54卷 4148-4160页

作者： NIU Yaoling1,2,3.1 Department of Earth Sciences, Durham university, Durham DH1 3.E, UK 2 School of Earth Sciences and Resources, china university of {3., Beijing 100083. china 3.School of Earth and Space Sciences, Peking university, Beijing 100871, china Department of Earth Sciences Durham University Durham DH1 3LE UK School of Earth Sciences and Resources China University of Geosciences Beijing 100083 China School of Earth and Space Sciences Peking University Beijing 100871 China

Basaltic magmatism that builds intra-plate ocean islands is often considered to be genetically associated with "hotspots" or "mantle plumes". While there have been many discussions on why ocean island basalts (OIB) are geochemically highly enriched as an integral part of the mantle plume hypothesis, our current understanding on the origin of OIB source material remains unsatisfactory, and some prevailing ideas need revision. One of the most popular views states that OIB source material is recycled oceanic crust (ROC). Among many problems with the ROC model, the ocean crust is simply too depleted (e.g., [La/Sm]PM > 1) OIB. Another popular view states that the enriched component of OIB comes from recycled continental crust (RCC, i.e.; terrigenous sediments). While both CC and OIB are enriched in many incompatible elements (e.g., both have [La/Sm]PM >>1), the CC has characteristic enrichment in Pb and deletion in Nb, Ta, P and Ti. Such signature is too strong to be eliminated such that CC is unsuitable as source material for OIB. Plate tectonics and mantle circulation permit the presence of ROC and RCC materials in mantle source regions of basalts, but they must be volumetrically insignificant in contributing to basalt magmatism. The observation that OIB are not only enriched in incompatible elements, but also enriched in the progressively more incompatible elements indicates that the enriched component of OIB is of magmatic origin and most likely associated with low-degree melt metasomatism. H2O and CO2 rich incipient melt may form in the seismic low velocity zone (LVZ). This melt will rise because of buoyancy and concentrate into a melt rich layer atop the LVZ to metasomatize the growing lithosphere, forming the metasomatic vein lithologies. Erupted OIB melts may have three components: (1) fertile OIB source material from depth that is dominant, (2) the melt layer, and (3. assimilation of the metasomatic

关键词：岩石成因论海洋 OIB 矿物学

The species diversity of fusulinaceans and high-frequency sea-level changes in the Carboniferous-Permian boundary section at Xikou, Zhen'an County,Shaanxi Province, china

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Science china Earth Sciences 2006年第7期49卷 673-683页

作者： ZHANG Haijun1, WANG Xunlian2, DING Lin1, XIA Guoying3.& WANG Lei2 1. Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100085, china 2. Faculty of Earth Sciences and Mineral Resources, china university of {3., Beijing 100083. china 3. Tianjin Institute of Geology and Mineral Resources, Tianjin 3.0170, china 1. Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China 2. Faculty of Earth Sciences and Mineral Resources China University of Geosciences Beijing 100083 China 3. Tianjin Institute of Geology and Mineral Resources Tianjin 300170 China

The study on the interrelation between sea-level changes and biodiversity with its evolu-tion has great significance for understanding the impact of global changes on organic evolution and exploring the inherent laws of life-environment coevolution in geological history. In this paper, the stratigraphic distribution of fusulinacean fauna in the Carboniferous-Permian boundary section at Xikou, Zhen’an County, Shaanxi Province, is analyzed quantitatively, and the relationship between the species diversity of fusulinaceans and relative sea-level changes is discussed. As a whole, the spe-cies numbers of fusulinacean fauna experience a rapid increase and an obvious decline in Xikou, Zhen’an County, from the Late Carboniferous to the Early Permian. There is a significant increase in species diversity around the Carboniferous-Permian boundary, which is one of the biggest bio-events of the fusulinacean fauna, and represents the radiation of Pseudoschwagerininae subfamily in the studied area. Integrated fusulinacean species diversity into sequence stratigraphic framework, de-tailed study suggests that the species diversity of the fusulinaceans is closely related to its relative stratigraphic location, and is essentially controlled by the sea-level changes, especially by the high-frequency sea-level changes. Generally, the species diversity of fusulinaceans is low, and the number of first and last appearance datum is small in the lower unit of high-frequency depositional cycle formed during the quick rise of the sea level; whereas the species diversity of fusulinaceans is high, and the number of first and last appearance datum is large in the upper unit of high-frequency cycle formed during the slow fall of the sea level. Within the third-order depositional sequence, the species diversity of the fusulinaceans at the first flooding surfaces and the maximum flooding surfaces is low, and it increases upward. The fusulinacean species diversity is low within the transgressive syst

关键词： fusulinaceans, species diversity, high-frequency cyclothem, sequence stratigraphy, sea-level changes, Carboniferous-Permian boundary, Zhen'an, Shaanxi.

The Dynamic Mechanisms for the Formation of Primary Metal Zoning of Cassiterite-Sulfide Deposits in the Gejiu Metallogenic Province, Yunnan

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Acta Geologica Sinica(English Edition) 1991年第1期65卷 51-63页

作者： Yu Chongwen Jiang Yaosong china university of geosciences, Beijing china university of geosciences Beijing

Copper and tin in cassiterite-sulfide deposits of the Gejiu metallogenic province are intimately associatedand show peculiar primary metal zoning. The authors made use of computer techniques to simulatenumerically the zoning of these ore deposits. The study shows that the regular spatial zoning probably resultedfrom the succession of multiple, intermittent and pulsatory mineralizations, The successive transports with di-verse velocities along channelways of the ore-forming solutions, taking place under conditions of definite dif-ference between metal concentrations, in solutions and wallrocks, followed by differential deposition, consti-tute possible dynamic mechanisms for the primary metal zoning.

关键词： Met rate The Dynamic Mechanisms for the Formation of Primary Metal Zoning of Cassiterite-Sulfide Deposits in the Gejiu Metallogenic Province Yunnan

Study on the two and three-parameter working stability regions of 3.-TZP suspension

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Science china(Technological Sciences) 2006年第5期49卷 547-568页

作者： CHEN Youqiang1, 2, ZHANG Xinni3. CHEN Sha’ou3.& QI Ping3.1. Department of Chemistry, Qingdao university, Qingdao 266071, {4. 2. Department of Chemistry, Tsinghua university, Beijing 100084. {4. 3. Department of Physics, Qingdao university, Qingdao 266071, {4. 1. Department of Chemistry Qingdao University Qingdao 266071 China 2. Department of Chemistry Tsinghua University Beijing 100084 China 3. Department of Physics Qingdao University Qingdao 266071 China

We determined the variation tendency of viscosity (η) at various solids load- ing (α) for 3.-TZP suspension as a function of dispersant concentration (Cw) using vis- cosity measurement, measured the diameter of particles as a function of Cw in very dilute suspension using light scattering method, and obtained the surface features of the sedi- ment of suspension with different Cw using SEM. We also discussed the influence of the microstructure of adsorbed polymer layers on particles and their interactions in the dis- persing medium on the stability of suspension. Then two different stable states and two different unstable states for 3.-TZP suspension were given. Accordingly, the (Cw, η), (Cw, α), and (α, η) two-parameter, and (Cw, α, η) three-parameter stability maps were con- structed. Based on the DLVO theory calculations, the dispersant concentration, particle distance (r), and interparticle potential energy (VT) maps with various solids loading for 3.-TZP aqueous suspension were also constructed. In (Cw, r) two-parameter coordinate system, the stable motion region map for particles was established. The Cw, α, and VT,max (the highest potential energy) surface of the potential barrier map was obtained through calculation and simulation on the basis of the surfaces of Cw, r, VT maps introduced above. The (Cw, α) two-parameter stability map was then obtained from the Cw, α, VT,max map. The results showed that this theoretical map can qualitatively prove the experimentally obtained results—the existence of different dispersed states of particles in suspension system and the variation tendency of suspension stability with changing each parame- ter—were reasonable.

关键词： 3.-TZP, suspension, stability, DLVO theory, interparticle potential energy.

Implementation of a multiple round quantum dense coding using nuclear magnetic resonance

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Science china(Physics,Mechanics & Astronomy) 2005年第6期48卷 706-715页

作者： ZHANG Jingfu1, XIE Jingyi2, WANG Chuan1, DENG Zhiwei3. LU Zhiheng4. & LONG Guilu1,5 1. Key Laboratory For Quantum Information and Measurements of MOE, Department of Physics, Tsinghua university, Beijing 100084.china 2. Department of Materials Science and Engineering, Beijing Normal university, Beijing 100875, china 3. Testing and Analytical Center, Beijing Normal university, Beijing 100875,china 4. Department of Physics, Beijing Normal university, Beijing 100875, china 5. Key Laboratory For atomic and Molecular Nanosciences, Tsinghua university, Beijing 100084.china 1. Key Laboratory For Quantum Information and Measurements of MOE Department of Physics Tsinghua University 100084 Beijing China 2. Department of Materials science and Engineering Beijing Normal University 100875 Beijing China 3. Testing and Analytical Center Beijing Normal University 100875 Beijing China 4. Department of Physics Beijing Normal University 100875 Beijing China 5. Key Laboratory For Atomic and Molecular Nanosciences Tsinghua University 100084 Beijing China

A multiple round quantum dense coding scheme based on the quantum phase estimation algorithm is proposed and implemented in a three qubit nuclear magnetic resonance (NMR) quantum computer. Using an m + 1 qubit system, Bob can transmit one of 2m+1 messages to Alice, through manipulating only one qubit and exchanging it between Alice and Bob for m rounds. The information capacity is enhanced to m + 1 bits as compared to m bits in a classical scheme. The scheme has been demonstrated in NMR system, and the experimental results show a good agreement between theory and experiment.

关键词： quantum dense coding, multiple round, nuclear magnetic resorance

Quantitative analysis on soil erosion based on 3. technology

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中国有色金属学会会刊：英文版 2005年第S1期15卷 82-85页

作者： JING Hai-tao~1, XIE Hong-quan~(2, 3., FU Mei-chen~2, FENG Zhong-ke~4.(1. Xuzhou Normal university, Xuzhou 221009, china 2. china university of Mining and Technology(Beijing Campus), Beijing 100083. china 3. Hebei Polytechnic university, Tangshan 063.09, china 4. Beijing Forestry university, Beijing 100083. china Xuzhou Normal Univ Xuzhou 221009 Peoples R China china Univ Min & Technol Beijing 100083 Peoples R China Hebei Polytech Univ Tangshan 063009 Peoples R China Beijing Forestry Univ Beijing 100083 Peoples R China

The quantitative analysis on soil erosion is very significant for macro-decision of soil loss, for quick control of natural disasters and for system of periodical report. Based on the research of 3.(GPS, GIS and RS), the special information can be obtained by GPS or RS. Digital elevation model can be formed by GIS software, and at the same time, we can get some vector graph, such as landuse, vegetation type and soil type. Then the soil erosion of research area was calculated by USLE. The methods and techniques were discussed, including how to carve up polygons, how to capture the values of factors and how to differentiate the erosion intensity.

关键词： soil erosion USLE GPS GIS RS

Based on the Spectral Variation of Vegetation Monitoring the Heavy Metal Pollution of Soil

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地学前缘 2009年第S1期16卷 86-87页

作者： Li Mi School of Information Engineering,china university of geosciences(Beijing),Beijing {3.china.

Heavy metal pollution of soil is one of serious problems of *** easy to break down, heavy metal was enriched and became the pollutants. It would not only destroy the normal function of soil and impede the growth of crops,but also through the food chain cause the harm to human *** the impact of heavy metal pollution of soil,the vegetation is also very easy to be *** the vegetation has been contaminated,its internal structure,

关键词： heavy metal pollution chlorophyll spectral variation red valley parameters

Late Mesozoic metamorphic core complexes: new constraints on lithosphere thinning in North china

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Progress in Natural Science:Materials International 2006年第6期16卷 633-638页

作者： LIU Junlai, GUAN Huimei, JI Mo and HU Ling (State Key Laboratory of Geological Processes and Mineral Resources, china university of geosciences, and Key Laboratory of Lithosphere Tectonics and Lithoprobing Technology of Ministry of Education, china university of geosciences, Beijing 100083. china) [a] State Key Laboratory of Geological Processes and mineral Resources China University of Geosciences Key Laboratory of Lithosphere Tectonics Beijing China [b] Lithoprobing Technology of Ministry of Education China university of Geosciences Beijing China

Metamorphic core complexes (mcc’s) are among the most prominent structural styles of lithosphere extension and thinning during late Mesozoic in North china. In this paper, the geometrical, kinematic and age characteristics of some of the mcc’s, e.g. Liaonan, Waziyu (Yiwulushan), Yunmengshan, etc., are discussed. Some common characteristics, such as kinematic polarity, geometric asymmetry, occurrence over a time span, scattered and isolated distribution, and progressive development, can provide direct constraints on the regional lithosphere extension and thinning in North china, which does not favor the prevailing plume model, a general de-lamination model or extensional collapse of overthickened orogenic crust. We argue that several aspects, such as the kinematic polarity at depths during lithosphere extension, gradual break-up of lithosphere plate, relationship between magmatism and regional extension, and coeval activity of mcc’s and Tan Lu fault, should be taken into consideration when constructing a more reasonable model for lithosphere extension and thinning in North china.

关键词： North china late Mesozoic metamorphic core complex lithosphere extension and thinning.