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The role of aerial algae in the formation of the landscape of the Yunnan Stone Forest,Yunnan Province, China

Science China Earth Sciences 2004年第9期47卷 846-864页

作者： TIAN Youping1,3. ZHANG Jie2, SONG Linhua1 & BAO Haosheng2 1. Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, beijing 100101, China 2. Department of Geography, Nanjing university, Nanjing 210093. China 3. School of Earth Sciences and Resources, China university of Geosciences, beijing 100083. China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of Sciences Beijing 100101 China Department of Geography Nanjing University Nanjing 210093 China School of Earth Sciences and Resources China University of Geosciences Beijing 100083 China

Aerial algae on the surface of carbonate rocks at the Stone Forest, Shilin County, Yunnan Province, China, and their bioerosion were investigated in the field and studied in the laboratory in detail. Through the observation, identification and statistics of more than one hun- dred algal samples and rock samples with the optical microscopes (stereomicroscope, biological microscope) and the scanning electronic microscope (SEM), the relationships between erosional forms on the surface of the Stone Forest and algae and/or algal communities and the genetic mechanism for the formation of erosional forms were analyzed. It is suggested that aerial algae play an active role in bioerosive processes that may affect the formation of karst erosional forms. These effects include both direct and indirect ones. The direct effect is the initiative control (algal shape-controlling role) of algae on the formation of karst forms of various scales, mostly mi- cro-scale (3.) and minor-scale (10-3.10-1m) erosional forms. The algal shape-controlling roles can be divided into the algal individual shape-controlling role and the algal community shape-controlling role. The former mostly controls the formation of micro-scale erosional forms, while the latter mostly controls the formation of micro-scale and smaller minor-scale erosional forms. The indirect effect refers to the promoting role of algae in the formation of karst forms, which may affect the formation of karst forms of all types and scales. The bioerosion of algae accelerates the weathering process of the whole Stone Forest karst landforms.

关键词： aerial algae, bioerosion, the Stone Forest, Yunnan Province, China.

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Chemical Extraction Preparation of Delithiated Cathode Materials of Li-ion Battery

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Journal of Wuhan university of technology(Materials Science) 2009年第6期24卷 863-866页

作者：闫时建 School of Materials Science and Engineering Taiyuan University of Science and Technology

A method of conventional chemical reaction to prepare delithiated cathode materials of Li-ion battery was introduced. The cathode material of Li-ion battery was mixed with oxidizing agent Na2S2O8 in water solution, and the solution was stirred continuously to make the chemical reaction proceed sufficiently, then the reaction product was filtered and finally the insoluble delithiated cathode material was obtained. A series of tests were conducted to verify the composition, crystal structure and electrochemical property of the delithiated cathode materials were all desirable. This method overcomes the shortcomings of battery charging preparation and chemical extraction preparation employing other oxidizing agents.

关键词： chemical extraction delithiated cathode material Li-ion battery

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Simulation study of phase retrieval for hard X-ray in-line phase contrast imaging

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Science China(Physics,Mechanics & Astronomy) 2005年第4期48卷 450-458页

作者： YU Bin1,2, PENG Xiang1,2, TIAN Jindong1, NIU Hanben1, DIAO Luhong3.& LI Hua3.1. Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education, Institute of Optoelec- tronics, Shenzhen university, Shenzhen 518060, China 2. State Key Laboratory of Precision Measuring technology and Instruments, Tianjin university, Tianjin 3.0072,China 3. Key Laboratory of Intelligent Information Processing, Institute of Computing technology, Chinese Academy of Sciences, beijing 100080,China 1. Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education Institute of Optoelectronics Shenzhen University 518060 Shenzhen China 2. State Key Laboratory of Precision Measuring technology and Instruments Tianjin University 300072 Tianjin China 3. Key Laboratory of Intelligent Information Processing Institute of Computing Technology Chinese Academy of Sciences 100080 Beijing China

Two algorithms for the phase retrieval of hard X-ray in-line phase contrast imaging are presented. One is referred to as Iterative Angular Spectrum Algorithm (IASA) and the other is a hybrid algorithm that combines IASA with TIE (transport of intensity equation). The calculations of the algorithms are based on free space propagation of the angular spectrum. The new approaches are demonstrated with numerical simulations. Comparisons with other phase retrieval algorithms are also performed. It is shown that the phase retrieval method combining the IASA and TIE is a promising technique for the application of hard X-ray phase contrast imaging.

关键词： X-ray optics, phase contrast imaging, phase retrieval, angular spectrum, hard X-ray.

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Effects of Surface-Active Elements Sulfur on Flow Patterns of Welding Pool

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Journal of Materials Science & technology 2005年第3期21卷 408-414页

作者： Yuzhen ZHAO, Yongping LEI and Yaowu SHI School of Materials Science and Engineering, beijing university of technology, beijing 100022, China School of Materials Science and Engineering Beijing University of Technology Beijing 100022 China

A 3. mathematical model is developed to calculate the temperature and velocity distributions in a moving gas tungsten arc (GTA) welding pool with different sulfur concentrations. It has been shown that, the weld penetration increases sharply with increasing sulfur content. When sulfur content increases beyond 80 × 10-6, the increase in sulfur content does not have an appreciable difference on the welding pool size and shape, and the depth/width remains constant. Sulfur changes the temperature dependence of surface tension coefficient from a negative value to a positive value and causes significant changes on flow patterns. The increase in soluble sulfur content and the decrease at free surface temperature can extend the region of positive surface tension coefficient. As sulfur content exceeds 125×10-6, the sign of surface tension coefficient is positive. Depending upon the sulfur concentrations, three, one or two vortexes that have different positions, strength and directions may be found in the welding pool. The contrary vortexes can efficiently transfer the thermal energy from the arc, creating a deep welding pool. An optimum range of sulfur content is 20-150×10-6.

关键词： Surface-active elements Sulfur Plow patterns Depth/width

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The evolution model of the earth's limited expanding

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Chinese Science Bulletin 2000年第4期45卷 304-313页

作者： CHEN ZhigengChina university of Mining and technology, beijing 100083. China China university of Mining and technology Beijing China

Based on the prerequisite that the earliest acid rock formed because of the initial global expanding tectonic processes, by combining it with other geological limitation conditions, and starting from the lithosphere elastic mechanics, the following is defined : the earth expansion started at about 43.0 Ma ago, the average increasing rate of the earth radius is 0.40 mm/a, the initial expanding earth radius is 4651 km, and the initial global expansion of tectonic processes happened at 4183.7 Ma ago. From the natural and attenuation evolution condition of the earth and terrestrial planets, through the limit condition got from the combination of the mathematics logic and the geological significance, the limited expanding earth evolution model is established as follows:in which R0= 4.651×106 m, A =1.86×106 m, β = -6.01?10-10 a and ts=3.10 a. From this model the maximum radius Rmax of the limited expanding earth evolution should be 6511 km. The earth’s radius increasing rate is about 0.1 mm/a at present.

关键词： limited earth expansion evolution model start time of expansion start time of expanding tectonism stage character of tectonism .

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ESKD-A New Structure of Expert System Based on Knowledge Discovery

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International Journal of Minerals,Metallurgy and Materials 2000年第1期14卷 63-71页

作者： Bingru Yang Fasheng liu Jiangtao Shen Information Engineering School, university of Science and technology beijing, beijing, 100083. China Information Engineering School University of Science and Technology Beijing Beijing 100083 China

A new structure of ESKD (expert system based on knowledge discovery system KD (D&K)) is first presented on the basis of KD (D&K)-a synthesized knowledge discovery system based on double-base (database and knowledge base) cooperating mechanism. With all new features, ESKD may form a new research direction and provide a great probability for solving the wealth of knowledge in the knowledge base. The general structural frame of ESKD and some sub-systems among ESKD have been described, and the dynamic knowledge base based on double-base cooperating mechanism has been emphased on. According to the result of demonstrative experi- ment, the structure of ESKD is effective and feasible.

关键词： knowledge discovery expert system dynamic knowledge base, double-base cooperating mechanism

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Secure network coding in the presence of eavesdroppers

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Science China(Information Sciences) 2010年第3期53卷 648-658页

作者： LUO MingXing1,2,3. YANG YiXian1,2,3. WANG LiCheng1,2,3.& NIU XinXin1,2,3.1Information Security Center, State Key Laboratory of Networking and Switching technology, beijing university of Posts and Telecommunications, beijing 100876, China 2Key Laboratory of Network and Information Attack and Defence technology of MOE, beijing university of Posts and Telecommunications, beijing 100876, China 3.ational Engineering Laboratory for Disaster Backup and Recovery, beijing university of Posts and Telecommunications, beijing 100876, China 1. Information Security Center State Key Laboratory of Networking and Switching Technology Beijing University of Posts and Telecommunications Beijing 100876 China2. Key Laboratory of Network and Information Attack and Defence Technology of MOE Beijing University of Posts and Telecommunications Beijing 100876 China3. National Engineering Laboratory for Disaster Backup and Recovery Beijing University of Posts and Telecommunications Beijing 100876 China

Our concern, in the paper, is to construct information-theoretic secure network coding in the presence of eavesdroppers. Based on the generalized attack model and all-or-nothing transformation, the security of network coding in the generalized combination network can be characterized by the network capacity and the min-cut bound of wiretapping set from the source. Furthermore, it can be extended to any directed acyclic networks with single source. Compared with the traditional results, we construct information-theoretic secure network coding without additional encryptions and giving up any capacity.

关键词： all-or-nothing transformation secure network coding eavesdropping

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BEHAVIOUR OF VACANCY INFLUENCE DURING DIFFUSION IN METALS

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Acta Metallurgica Sinica(English Letters) 1992年第6期5卷 395-401页

作者： ZHANG Sanhong HE Xinlai CHU Youyi KE Jun (T.Ko) university of Science and technology beijing,China Doctor,Department of Materials Physics,university of Science and technology beijing,beijing 100083 beijing Univ of Science and Technology Beijing China

The effects of vacancies on diffusion of interstitial and substitutional atoms as well as interaction between them in metals were *** the interstitial alloy,a coupling between interstitial atoms and vacancy is interre... 详细信息

关键词： vacancy diffusion Fick's law

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Change Laws of Flake's Temperature during Making a Diamond Film by DC-PJ

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International Journal of Minerals,Metallurgy and Materials 1999年第2期13卷 97-102页

作者： Xuhong Chen Lihe Zhao Fanxiu Lu(Mechanical Engineering School, university of Science and technology beijing, beijing 100083. China) Mechanical Engineering School University of Science and Technology Beijing Beijing 100083 China

When making a diamond film by direct current plasma jet, a kind piece of flake is used as a base body Which the film can beattached to. The flake's temperature is unstable. Therefore, some experiments and constructed mathematical models, which were solvedby computer, were done. The results show that the flake's temperature is influenced by many factors and the mains are plasma jet powerand vacuum pressure. Through adjusting the two parameters, the flake's temperature can be accurately controlled, furthermore, diamondfilms' quality would be improved. Lowering sediment platform's temperature has a little effect to the flake's temperature at present technology conditions.

关键词： CVD (Chemical Vapor Deposition) plasma, impact heat transfer

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Influence of Ru addition on microstructure and stress-rupture property of Ni-based single crystal superalloys

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Progress in Natural Science:Materials International 2010年第1期20卷 61-69页

作者： Jing-yang CHEN~1,Qiang FENG~(1,2),La-mei CAO~3.Zu-qing SUN~1 1.State Key Laboratory for Advanced Metals and Materials,university of Science and technology beijing, beijing 100083.China 2.National Center for Materials Service Safety,university of Science and technology beijing,beijing 100083.China 3.National Key Laboratory of Science and technology on Advanced High Temperature Structural Materials, beijing Institute of Aeronautical Materials,beijing 100095,China Univ Sci & Technol beijing State Key Lab Adv Met & Mat Beijing 100083 Peoples R China Univ Sci & Technol beijing Natl Ctr Mat Serv Safety Beijing 100083 Peoples R China beijing Inst Aeronaut Mat Natl Key Lab Sci & Technol Adv High Temp Struct M Beijing 100095 Peoples R China

The effects of Ru on the microstructure and stress-rupture property were investigated in two experimental Ni-based single crystal superalloys with and without Ru addition(5.1%,mass fraction).The results indicate that the morphology ofγ' precipitates in the dendrite core and interdendritic region are intermediate and nearly spherical,respectively,in the Ru-free alloy after being aged at 1100℃for 8 *** Re partitioning ratio increases due to Ru addition and Ru partitioned preferentially to theγphase in both dendrite core and interdendritic region of the Ru-containing alloy,which results in more negative lattice misfit and more cuboidalγ' ***,theγ' volume fraction increases while the precipitate size and y channel width decreases due to Ru addition in both dendrite core and interdendritic *** addition improves the stress-rupture life at 1100℃/140 MPa significantly due to higherγ' volume fraction,more negative lattice misfit and a well rafting structure as well as lessγchannel width.

关键词： Ni-based superalloys ruthenium elemental partitioning ratio lattice misfit γ’ morphology stress-rupture property

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