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Totally geodesic submanifolds of maximal rank in symmetric spaces

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Science China Mathematics 2004年第2期47卷 264-271页

作者： ZHU Fuhai & LIANG KeSchool of Mathematical Sciences and lmam, {1., beijing {3. China College of Mathematical Sciences and LPMC, Nankai university, Tianjin 3.0071. China 1.School of Mathematical Sciences and lmam Peking University 100871 Beijing China 2.College of Mathematical Sciences and LPMC Nankai University 300071 Tianjin China

We gave a complete list of totally geodesic submanifolds of maximal rank in symmetric spaces of noncompact type. The compact cases can be obtained by the duality.

关键词： totally geodesic submanifold, Lie triple system, maximal rank.

Electronic structure and magnetism of R(Fe,Si)_(1.) (R=Y,Nd)

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Science China(Physics,Mechanics & Astronomy) 2006年第2期49卷 195-202页

作者： SUN Guang’ai1. CHEN Bo1. DU Honglin2, FAN Zhijian1. GAO Tao3.& QI Xinhua3.. Institute of Nuclear Physics and Chemistry, China Academy of Engineering Physics, Mianyang 621.00, China 2. Department of physics, peking university, beijing 1.0871. China 3. Institute of Atomic and Molecular Physics, Sichuan {3., Chengdu 61.065, China 1. Institute of Nuclear Physics and Chemistry China Academy of Engineering Physics Mianyang 621900 China 2. Department of physics Peking university Beijing 100871 China 3. Institute of Atomic and Molecular Physics Sichuan University Chengdu 610065 China

The newly developed full-potential linearized augmented plane wave (LAPW) and local orbitals (lo) based on standard APW methods are briefly introduced, and the structure and magnetic properties of R(Fe, Si)1. compounds (R = Y, Nd) are calculated using the method. The distribution of Si at different sites is analyzed based on total energy of one crystal unit with structure having been optimized. The characters of magnetic mo-ments, total density of states (TDOS) and partial density of states (PDOS) for different crystal sites Si occupies are obtained and analyzed. The results show that the total mag-netic moments of RFe1.Si2 (R = Y, Nd) are larger than those of RFe1.M2 (M = Ti, V, Cr, Mn, Mo and W) and the hybridization mechanism is seen as follows. Si(8j) reduce the mag-netic moments of Fe at three sites, however, Si(8f) mainly reduce the magnetic moments of Fe(8i) and Fe(8j) atoms. The Curie temperature is markedly enhanced by the introduc-tion of Si atoms according to spin fluctuation of DOS at Fermi level.

关键词： (L)APW+lo method R(Fe Si)1.(R = Y Nd) magnetic moment Density of state.

Weight hierarchies of linear codes satisfying the Near-Chain condition

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Progress in Natural Science:Materials International 2005年第9期15卷 784-792页

作者： LIU Zihui1.* and CHEN Wende2(1. School of Mathematical Sciences, peking university, {1. 1.0871. China 2. Laboratory of Systems and Control and Key State Laboratory of Information Security, Institute of Systems Science, Academy of Mathematics and Systems Science, Chinese Academy of Sciences, {1. 1.0080, China) School of Mathematical Sciences Peking University Beijing 100871 China. Laboratory of Systems and Control and Key State Laboratory of Information Security Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100080 China

The weight hierarchies of a linear [n,k;q] code C satisfying the Near-Chain condition are studied, almost all the weight hierarchies of such code are determined.

关键词： weight hierarchy Near-Chain condition difference sequence linear code.

Development and Application of High Performance X80 Line Pipe for the 2^(nd) West-East Gas Pipeline

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Journal of Iron and Steel Research International 2011年第S1期18卷 39-48页

作者： LI He-lin 1., HUO Chun-yong 1., JI Ling-kang 1. 2 , LI Yang 1. 3.(1. CNPC Tubular Goods Research Institute, Xi’an 71.065, China 2. . School of Material Science and Engineering, Xi’an Jiaotong {1., Xi’an 71.049, China 3. School of Material Science and Engineering, {1. of Science and Technology beijing, beijing 1.0083. China) CNPC Tubular Goods Res Inst Xian 710065 Peoples R China Xi An Jiao Tong Univ Sch Mat Sci & Engn Xian 710049 Peoples R China Univ Sci & Technol beijing Sch Mat Sci & Engn Beijing 100083 Peoples R China

It is the development tendency of gas pipeline to improve strength of line pipe and transmission pressure, which is an important symbol of the progress of gas pipeline technology. The 2nd West-East Gas Pipeline (the 2 nd WEGP) is the largest-scale X80 high pressure gas pipeline project in the world. Through the joint development project by Pipeline Company, research institute, and steel company, a series of achievements of technology have been obtained, which makes it possible to apply pressure of 1. MPa and X80 LSAW and HSAW pipe for the 2 nd WEGP. Specifications of X80 steel and pipe have been issued based on API 5L. High performance X80 steel and pipe have been developed and meets the Specification. General design conception of applying HSAW pipe and LSAW pipe on gas transmission trunk line with large diameter and high pressure has been established. Failure control of the 2 nd WEGP has been carried out to avoid failure and reduce the lost which based on analysis of pipeline failure mode. In this paper, research and development of high performance X80 welded pipe, establishment of technical route of joint application of HSAW and LSAW steel pipe and key technology of failure control are emphatically discussed.

关键词： 2 nd WEGP acicular ferrite failure control arrest toughness strain-based design

Investigating spatial distribution of tourist attractions’inlinks: A case study of three mountains

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Science China(Technological Sciences) 2010年第S1期53卷 126-133页

作者： ZHANG Yi 1.QI LiNa 2,YANG AnRan 1.SHI Lei 1.& XU Li 1.1.Institute of RS and GIS,peking university,{1. 1.0871.China 2 Center for Recreation and Tourism Research,peking university,{1. 1.0871.China peking Univ Inst RS & GIS Beijing 100871 Peoples R China peking Univ Ctr Recreat & Tourism Res Beijing 100871 Peoples R China

In hyperlink analysis,most researchers focus on interpreting hyperlink counts,they seldom concern themselves enough about the significance of spatial distribution of *** this paper,we argue that not only can the inlink count to a tourist attraction’s official website reflect its attractiveness,but also the spatial distribution of its inlinks can reflect the distribution of its tourist source *** mountains in Anhui Province,China,are chosen for the case ***,the correlation between the spatial distributions of an attraction’s tourist source markets and its official website’s inlinks is ***,the tourism indexes such as the spatial concentration index(SCI)and the attraction radius(AR),which are calculated by inlinks,are compared to the real indexes based on tourist ***,the detailed discussion and analysis are presented and an improved model,which is used to calculate the distribution of inlinks,is proposed.

关键词： tourist attractiveness hyperlink analysis spatial distribution of hyperlinks tourist source market

Discovery and character of the Kunlun-Yellow River Movement

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Chinese Science Bulletin 1998年第10期43卷 833-836页

作者： CUI Zhijiu 1. WU Yongqiu 2,3.and LIU Gengnian 1.1. Department of Geography, {1., beijing 1.0871. China 2. Open Research Laboratory of Environmental Changes and Natural Disaster of State Education Commission, beijing 1.0875, China Department of Geography Peking University Beijing China Open Research Laboratory of Environmental Changes and Natural Disaster of State Education Commission Beijing China Department of Geography Sichuan Normal Uni-versity Chengdu China

Based on geomorphological, tectonic and sedimentary data, a Kunlun Yellow River Tectonic Movement has been recognized in 1.1.-0 60 Ma B.P. This tectonic movement, which leads to uplift of the Qinghai_Xizang (Tibet) Plateau from 1.500 to 3.000-3.500 m, is periodic, abrupt and changeable in the movement rate of uplifting and slide slipping.

关键词： Kunlun Mountain Pass 700 kaB.P. tectonic movement.

Two possible mechanisms for vortex self-organization

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Science China Earth Sciences 2006年第2期49卷 202-211页

作者： LUO Zhexian2, ZHOU Xiuji1.& GAO Shouting3.1. Chinese Academy of Meteorological Sciences, {1. 1.0081. China 2. Department of Space Information Science, Nanjing university of Information Science and Technology, Nanjing 21.044, China 3. Institute of Atmospheric Physics, Chinese Academy of Sciences, {1. 1.0029, China 2. Department of Environmental Science Nanjing University of Information Science and Technology Nanjing 210044 China 1. Chinese Academy of Meteorological Sciences Beijing 100081 China 3. Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The vortex self-organization is investigated in this paper by four groups of numerical experiments within the framework of quasi-geostrophic model, and based on the experimental results two types of possible mechanisms for vortex self-organization are suggested. The meso-scale to-pography may enable separated vortices to merge into a larger scale vortex; and the interaction of meso-γ and meso-β scale systems may make separated vortices to self organize a typhoon-like vor-tex circulation.

关键词： vortex, self-organization, meso-scale topography, interaction of different scales.

Phase relationship of complex multi-component system in chromate cleaner production

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Progress in Natural Science:Materials International 2007年第7期17卷 845-850页

作者： Ge Xinlei~1.Wang Xidong~(1.3.*) Zheng Shili~2 Zhang Mei~1.Zhang Yi~2 (1.Department of Physical Chemistry,{1. of Science and Technology beijing,beijing 1.0083.China 2.Institute of Process Engineering,Chinese Academy of Sciences,beijing 1.0080,China 3.College of Engineering,peking university,beijing 1.0871.China) [a]Department of Physical Chemistry University of Science and Technology Beijing Beijing China [b]College of Engineering Peking University Beijing China [c]Institute of Process Engineering Chinese Academy of Sciences Beijing China

The phase relationships of the complex multi-component systems in the liquid-phase oxidization and separation process related with the chromate cleaner production are investigated theoretically and *** phase diagram of main system Fe- Cr2O4-KOH-O2of oxidization process and the relationship of its standard Gibbs free energy change with temperature are calculated.A se- ries of phase diagrams of the separation process at different temperatures,such as K（Na）OH-K（Na）2CrO4-H2O,KOH-KAlO2-H2O, K（Na）OH-K（Na）2CO3.H2O,K（Na）OH-K（Na）HCO3.H2O and K（Na）HCO3.K（Na）2CrO4-H2O have also been *** ex- periments are carried out to verify the calculated *** results showed that the sub-molten salt media are suitable for the oxidization and separation processes;FeCr2O4can be oxidized across a wide range of temperature;K（Na）2CrO4can be separated from K（Na）AlO2system at appropriate temperature and proper concentration;the crystallization of carbonate is easier than that of K（Na）2CrO4.

关键词： chromite chromate system thermodynamics calculation phase diagram

Efficient visualization techniques for high resolution remotely sensed data in a network environment

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Science China(Technological Sciences) 2008年第S1期51卷 124-134页

作者： WENG JingNong1.WU Lun2,HUANG Jian1.XIA YuBin3.& CAI Heng1.1.College of Software,Beihang {1.,beijing 1.0083.China 2 Institute of Geographical Information System and Remote Sensing,peking university,beijing 1.0871.China 3.College of Computer,Beihang {1.,beijing 1.0083.China 1. College of Software Beihang University Beijing 100083 China2. Institute of Geographical Information System and Remote Sensing Peking University Beijing 100871 China3. College of Computer Beihang University Beijing 100083 China

There are three major research hotspots in efficient visualization techniques of high resolution remotely sensed data in network environment: the data organiza-tion and access in disk storage,the image data stitching and fitting methods,and the network transfers and access. In this paper a new method of "Big File" organi-zation for improving the storage access efficiency of high resolution remote data is presented; a "virtual data source" concept is introduced to solve the stitching problem of remotely sensed data from different sources with different resolutions; a remotely sensed data access engine design based on ATL technique is discussed to process the network transfers and access of remotely sensed data. All these techniques have been adopted in a prototype of digital China named "ChinaStar".

关键词： high resolution remotely sensed data spatial index pyramid model LOD Big File