检索结果-南通市图书馆

Science china(Technological sciences) 2005年第z1期48卷 146-156页

作者： zhang lei1,2. wei zuoan1, liU {2. & li shihai1 1.institute of mechanics, chinese academy of sciences, beijing 100080, china 2.Graduate School, chinese academy of sciences, beijing 100060, china chinese Acad Sci Inst Mech Beijing 100080 Peoples R China chinese Acad Sci Grad Sch Beijing 100060 Peoples R China

Three-dimensional discrete element face-to-face contact model with fissure water pressure is established in this paper and the model is used to simulate three-stage process of landslide under fissure water pressure in the opencast mine, according to the actual state of landslide in Panluo iron mine where landslide happened in 1990 and was fathered in 1999. The calculation results show that fissure water pressure on the sliding surface is the main reason causing landslide and the local soft interlayer weakens the stability of slope. If the discrete element method adopts the same assumption as the limit equilibrium method, the results of two methods are in good agreement; while if the assumption is not adopted in the discrete element method, the critical φ numerically calculated is less than the one calculated by use of the limit equilibrium method for the sameC. Thus, from an engineering point of view, the result from the discrete element model simulation is safer and has more widely application since the discrete element model takes into account the effect of rock mass structures.

关键词： face-to-facecontactmodel, fissure water pressure, three-dimensional discrete element method,landslide.

Characterization of plastic flow in two Zr-based bulk metallic glasses

在线全文

学校读者我要写书评

暂无评论

Science china(Technological sciences) 2006年第4期49卷 414-424页

作者： XING Dongmei1,2. zhang Taihua1, li weihuo3 & wei Bingchen3 1. State Key Laboratory of Nonlinear mechanics (LNM), institute of mechanics, chinese academy of Sci- ences, beijing 100080, china 2. College of Physics and Electronic Information Science, Tianjin Normal University, Tianjin 300074, china 3. National Microgravity Laboratory, institute of mechanics, chinese academy of sciences, beijing 100080, china 1. State Key Laboratory of Nonlinear mechanics (LNM) Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China 2. College of Physics and Electronic Information Science Tianjin Normal University Tianjin 300074 China 3. National Microgravity Laboratory Institute of Mechanics Chinese Academy of Sciences Beijing 100080 China

Plastic deformation behaviors of Zr65Al10Ni10Cu15 and Zr52.5Al10Ni10Cu15Be12.5 bulk metallic glasses (BMGs) are studied by using the depth-sensing nanoindentation, microindentation and uniaxial compression. The Be-containing BMG exhibits a signifi- cantly improved overall plastic strain compared with the Be-free alloy during compressive tests. Both BMGs show a loading-rate-dependent serrated flow during nanoindentation measurements, but the Be-containing alloy exhibits a much lower critical loading rate for the disappearance of the serration than the Be-free BMG. The shear band patterns de- veloped during plastic deformation are investigated by microindentation technique, wherein much higher shear band density is found in the Be-containing alloy than in the Be-free alloy, indicating an easier nucleation of shear bands in the former BMG. The dif- ference in the plastic deformation behavior of the two BMGs can be explained by a free volume model.

关键词： Bulk metallic glass, plastic deformation, shear band, nanoindentation.

Remote sensing based shrub above-ground biomass and carbon storage mapping in Mu Us desert,china

在线全文

学校读者我要写书评

暂无评论

Science china(Technological sciences) 2010年第S1期53卷 176-183页

作者： XU Min 1,2.CAO ChunXiang 1,TONG QingXi 1,li ZengYuan 3,zhang Hao 1,HE QiSheng 1,2.GAO MengXu 1,2.ZHAO Jian 1,2.ZHENG Sheng 1,2.CHEN wei 1,2.& ZHENG LanFen 1 1State Key Laboratory of Remote Sensing Science,Jointly Sponsored by the {2. of Remote Sensing Applications of chinese academy of sciences and beijing Normal University,beijing 100101,china 2.Graduate School of the chinese academy of sciences,beijing 100049,china 3 Research {2. of Forest Resources and Information Techniques,chinese {12. of Forestry,beijing 10009,china 1. State Key Laboratory of Remote Sensing Science Jointly Sponsored by the Institute of Remote Sensing Applications of Chinese Academy of Sciences and Beijing Normal University Beijing 100101 China 2. Graduate School of the chinese academy of sciences Beijing 100049 China 3. Research institute of Forest Resources and Information Techniques Chinese Academy of Forestry Beijing 10009 China

The estimation of above-ground biomass(AGB) and carbon storage is very important for arid and semi-arid ***-1A/B satellite data combined with field measurement data was used for the estimation of shrub AGB and carbon storage in the Mu Us desert,*** correlations of shrub AGB and spectral reflectance of four bands as well as their combined vegetation indexes were respectively analyzed and stepwise regression analysis was employed to establish AGB prediction *** prediction equation based on ratio vegetation index(RVI)was proved to be more suitable for shrub AGB estimation in the Mu Us desert than *** AGB and carbon storage were mapped using the RVI based prediction model in *** statistics showed the western Mu Us desert has relatively high AGB and carbon storage,and that the gross shrub carton storage in Mu Us desert reaches 16 799 2.0 t,which has greatly contributed to the carbon fixation in northern china.

关键词： above-ground biomass carbon storage Mu Us desert HJ-1A/B remote sensing

Generation of surface electrons in femtosecond laser-solid interactions

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,mechanics & Astronomy) 2006年第3期49卷 335-340页

作者： XU Miaohua1, li Yutong1, YUAN Xiaohui1,2. ZHENG Zhiyuan1, liANG Wenxi1, YU Quanzhi1, zhang Yi1, WANG Zhaohua1, wei Zhiyi1 & zhang Jie1 1. Key Laboratory of Optical Physics, institute of Physics, chinese academy of sciences, beijing 100080, china 2. State Key Laboratory of Transient Optics Technology, chinese academy of sciences, Xi’an 710068, china Key Laboratory of Optical Physics Institute of Physics Chinese Academy of Sciences Beijing 100080 China State Key Laboratory of Transient Optics Technology Chinese Academy of Sciences Xi’an 710068 China

The characteristics of hot electrons produced by p-polarized femtosecond laser-solid interactions are studied. The experimental results show that the outgoing electrons are mainly emitted in three directions: along the target surface, the normal direction and the laser backward direction. The electrons flowing along the target surface are due to the confinement of the electrostatic field and the surface magnetic field, while the electrons in the normal direction due to the resonant absorption.

关键词： hot electrons,surface magnetic field,femtosecond laser pulses

Characterization of GLUT4-containing vesicles in 3T3-L1 adipocytes by total internal reflection fluorescence microscopy

在线全文

学校读者我要写书评

暂无评论

Science china(life sciences) 2009年第7期52卷 665-671页

作者： WANG Yan1,2.zhang JinZhong1,2.CHEN Yu1,2.JIANG li1,2.JI wei1,2.& XU Tao1 1 National Laboratory of Biomacromolecules,{2. of Biophysics,chinese academy of sciences,beijing 100101,china 2.Graduate University of chinese academy of sciences,beijing 100049,china 1. National Laboratory of Biomacromolecules Institute of Biophysics Chinese Academy of Sciences Beijing 100101 China 2. Graduate University of chinese academy of sciences Beijing 100049 China

Insulin-responsive GLUT4(glucose transporter 4) translocation plays a major role in regulating glucose uptake in adipose tissue and *** or not there is a specialized secretory GSV(GLUT4 storage vesicle) pool,and more importantly how GSVs are translocated to the PM(plasma membrane) under insulin stimulation is still under *** the present study,we systematically analyzed the dynamics of a large number of single GLUT4-containing vesicles in 3T3-L1 adipocytes by TIRFM(total internal reflection fluorescence microscopy).We found that GLUT4-containing vesicles can be classified into three groups according to their mobility,namely vertical,stable,and lateral GLUT4-containing *** these groups,vertical GLUT4-containing vesicles exclude transferrin receptors and move towards the PM specifically in response to insulin stimulation,while stable and lateral GLUT4-containing vesicles contain transferrin receptors and show no insulin *** data demonstrate that vertical GLUT4-containing vesicles correspond to specialized secretory GSVs,which approach the PM directly and bypass the constitutive recycling pathway.

关键词： GLUT4 IRAP-pHluorin GSV transferring TIRFM

Electronic structure and magnetic properties of metastable SmCo_(7) compound

在线全文

学校读者我要写书评

暂无评论

Science china(Physics,mechanics & Astronomy) 2005年第3期48卷 325-335页

作者： zhang Changwen 1 , li Hua 1 , DONG Jianmin 1 , WANG Yongjuan 1 , PAN Fengchun 1 , zhang Jian 1 , GUO Yongquan 2.& li {2. 2.1. School of Physics and Microelectronics, Shandong University, Jinan 2.0100, china 2. institute of Functional Materials, Central Iron and Steel Research institute, beijing 100081, china 1. School of Physics and Microelectronics Shandong University 250100 Jinan China 2. institute of Functional Materials Central Iron and Steel Research Institutes 100081 Beijing China

The electronic density of states, spin-splittings and atomic magnetic moments of SmCo 7 compound have been studied using spin-polarized MS-Xα method. The results show that a few of electrons are transferred to Sm(5d 0 ) orbital because of orbital hybridization between Sm and Co atoms in the compound. The exchange interactions between 3d and 5d electrons lead to the magnetic coupling between Sm and Co, and therefore, result in the long-range ferromagnetic order inside the SmCo 7 compound. There are negative exchange couplings occurring at some levels, which weakens the strength of average coupling around Co lattice. So, the Curie temperature and Co-moment of SmCo 7 decrease distinctly compared with pure Co. Compared with SmCo 5 compound, the disordered substitution of Co-Co “dumbbell-atom” pairs for Sm changes the local environment of Co lattice, which makes the 2. site bear negative magnetic moment. The strength of hybridization near Fermi level weakens and the free energy of the compound increases obviously. Thus, SmCo 7 is a metastable compound at room temperature. Considering the localization of 4f electrons and a few of 5d electrons arising from the orbital hybridization, the magnetic moment of Sm atom will be 1.61μ B in SmCo 7 compound, which is in agreement with the experimental values of Sm 3+ ion- moment and Sm atom-moment in metals.

关键词： electronic structure, spin polarization, atomic magnetic moment, exchange coupling, Curie temperature.

Monaural voiced speech segregation based on elaborate harmonic grouping strategies

在线全文

学校读者我要写书评

暂无评论

Science china(Information sciences) 2011年第12期54卷 2491-2500页

作者： liU WenJu 1 , zhang Xueliang 1 , JIANG wei 1 , li Peng 2.& XU Bo 2.1 National Laboratory of Pattern Recognition, {2. of Automation, chinese academy of sciences, beijing 100190, china 2.Digital Media Content Technology Research Center, {2. of Automation, chinese academy of sciences, beijing 100190, china 1. National Laboratory of Pattern Recognition Institute of Automation Chinese Academy of Sciences Beijing 100190 China2. Digital Media Content Technology Research Center Institute of Automation Chinese Academy of Sciences Beijing 100190 China

In this paper, an enhanced algorithm based on several elaborate harmonic grouping strategies for monaural voiced speech segregation is proposed. Main achievements of the proposed algorithm lie in three aspects. Firstly, the algorithm classifies the time-frequency (T-F) units into resolved and unresolved ones by carrier-to-envelope energy ratio, which leads to more accurate classification results than by cross-channel correlation. Secondly, resolved T-F units are grouped together according to minimum amplitude principle, which has been verified to exist in human perception, as well as the harmonic principle. Finally, "enhanced" envelope autocorrelation function is employed to detect amplitude modulation rates, which helps a lot in reducing half-frequency error in grouping of unresolved units. Systematic evaluation and comparison show that performance of separation is greatly improved by the proposed algorithm. Specifically, signal-to-noise ratio (SNR) is improved by 0.96 dB compared with that of previous method. Besides, our algorithm is also effective in improving the PESQ score and subjective perception score.

关键词： computational auditory scene analysis voiced speech separation harmonistic principle minimum amplitude principle elaborate harmonic grouping strategies

Primary scientific results of Chang'E-1 lunar mission

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china Earth sciences 2010年第11期53卷 1565-1581页

作者： OUYANG ZiYuan1,2. li ChunLai1, ZOU Yongliao1, zhang HongBo1, Lü Chang1, liU JianZhong1, liU JianJun1, ZUO wei1, SU Yan1, WEN weiBin1, BIAN wei1, ZHAO BaoChang3, WANG JianYu4, YANG JianFeng3, CHANG Jin5, WANG HuanYu6, zhang XiaoHui7, WANG ShiJin7, WANG Min1, REN Xin1, MU lingli1, KONG DeQing1, WANG XiaoQian1, WANG Fang1, GENG liang1, zhang ZhouBin1, ZHENG lei1, ZHU XinYing1, ZHENG YongChun1, li JunDuo1, ZOU XiaoDuan1, XU Chun1, SHI ShuoBiao1, GAO YiFei1 & GAO GuanNan1 1 National Astronomical Observatories, chinese academy of sciences, beijing 100012. china 2.institute of Geochemistry, chinese academy of sciences, Guiyang 550002. china 3 Xi’an institute of Optics and Precision mechanics, chinese academy of sciences, Xi’an 710119, china 4 Shanghai institute of Technical Physics, chinese academy of sciences, Shanghai 2.0083, china 5 Purple Mountain Observatory, chinese academy of sciences, Nanjing 2.0008, china 6 institute of High Energy Physics, chinese academy of sciences, beijing 100049, china 7 Center for Space Science and Applied Research, chinese academy of sciences, beijing 100190, china 1. National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China2. Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China3. Xi’an Institute of Optics and Precision Mechanics Chinese Academy of Sciences Xi’an 710119 China4. Shanghai Institute of Technical Physics Chinese Academy of Sciences Shanghai 200083 China5. Purple Mountain Observatory Chinese Academy of Sciences Nanjing 210008 China6. Institute of High Energy Physics Chinese Academy of Sciences Beijing 100049 China7. Center for Space Science and Applied Research Chinese Academy of Sciences Beijing 100190 China

The strategic plan for the development of the unmanned chinese Lunar Exploration Program is characterized by three distinct stages: "orbiting around", "landing on" and "returning from" the Moon. The first chinese lunar probe, Chang'E-1, which was successfully launched on October 2.th, 2.07 at Xichang Satellite Launch Center, and guided to crash on the Moon on March 1st, 2.09, at 52.36°E, 1.50°S, in the north of Mare Fecunditatis, is the first step towards the "orbiting around" stage. The Chang'E-1 mission lasted 495 days, exceeding the expected life-span by about four months. A total of 1.37 TB raw data was received from Chang'E-1. It was then processed into 4 TB scientific data products at various levels. Many scientific results have been obtained by analyzing these data, including especially the "global lunar image from the first chinese lunar explora- tion mission". All scientific goals of Chang'E-1 have been achieved. It provides much useful materials for further advances of lunar sciences and planetary chemistry. Meanwhile, these results will serve as a firm basis for future chinese lunar missions.

关键词： lunar orbiter Chang’E-1 scientific data results

The global image of the Moon obtained by the Chang'E-1:Data processing and lunar cartography

在线全文

学校读者我要写书评

暂无评论

Science china Earth sciences 2010年第8期53卷 1091-1102页

作者： li ChunLai1, liU JianJun1, REN Xin1, MOU lingli1, ZOU Yongliao1, zhang HongBo1, Lü Chang1, liU JianZhong1, ZUO wei1, SU Yan1, WEN weiBin1, BIAN wei1, ZHAO BaoChang2. YANG JianFeng2. ZOU XiaoDuan1, WANG Min1, XU Chun1, KONG DeQing1, WANG XiaoQian1, WANG Fang1, GENG liang1, zhang ZhouBin1, ZHENG lei1, ZHU XinYing1, li JunDuo1 & OUYANG ZiYuan11 National Astronomical Observatories, chinese academy of sciences, beijing 100012. china 2.Xi’an institute of Optics and Precision mechanics, chinese academy of sciences, Xi’an 710119, china 1. National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China2. Xi’an Institute of Optics and Precision Mechanics Chinese Academy of Sciences Xi’an 710119 China

The global lunar image of the first phase of chinese Lunar Exploration Program is the first image that covered all over the surface of the Moon. It will serve as a critical foundation for succeeding exploration and scientific research. In this paper, the acquisition, characteristics, and data quality of Chang'E-1 CCD image data are described in detail. Also described are the methodology and procedure of data processing. According to rule of planetary cartography, the image data have been processed, geometrically corrected, and then mosaicked and merged in a scale of 1:2.5 million. The results of data processing and charting show that the image data of Chang'E-1 CCD and their geometric precision meet the demand of charting a map in the scale of 1:2.5 million. The relative geometric positioning precision of the global image is better than 2.0 m, and the absolute geometric positioning precision is slightly better than that of the ULCN2.05 and Clementine lunar basemap (V2.0). The plane positioning precision is approximately 100-1500 m. This global image proves to be the best global image of the Moon so far in terms of space coverage, image quality, and positioning precision.

关键词： Chang’E-1 lunar CCD data processing lunar image position lunar global image

Laser altimetry data of Chang'E-1 and the global lunar DEM model

在线全文

学校读者我要写书评

暂无评论

Science china Earth sciences 2010年第11期53卷 1582-1593页

作者： li ChunLai1, REN Xin1, liU JianJun1, ZOU XiaoDuan1, MU lingli1, WANG JianYu2. SHU Rong2. ZOU Yongliao1, zhang HongBo1, Lü Chang1, liU JianZhong1, ZUO wei1, SU Yan1, WEN weiBin1, BIAN wei1, WANG Min1, XU Chun1, KONG DeQing1, WANG XiaoQian1, WANG Fang1, GENG liang1, zhang ZhouBin1, ZHENG lei1, ZHU XinYing1, li JunDuo1 & OUYANG ZiYuan1 1 National Astronomical Observatories, chinese academy of sciences, beijing 100012. china 2.Shanghai institute of Technical Physics, chinese academy of sciences, Shanghai 2.0083, china 1. National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China2. Shanghai Institute of Technical Physics Chinese Academy of Sciences Shanghai 200083 China

The Laser AltiMeter (LAM), as one of the main payloads of Chang'E-1 probe, is used to measure the topography of the lunar surface. It performed the first measurement at 02.2. on November 2.th, 2.07. Up to December 4th 2.08, the total number of measurements was approximately 9.12.million, covering the whole surface of the Moon. Using the LAM data, we constructed a global lunar Digtal Elevation Model (DEM) with 3 km spatial resolution. The model shows pronounced morphological characteristics, legible and vivid details of the lunar surface. The plane positioning accuracy of the DEM is 445 m (1σ), and the vertical accuracy is 60 m (1σ). From this DEM model, we measured the full range of the altitude difference on the lunar sur-face, which is about 19.807 km. The highest point is 10.62. km high, on a peak between crater Korolev and crater Dirichlet-Jackson at (158.656°W, 5.441°N) and the lowest point is -9.178 km in height, inside crater Antoniadi (172.413°W, 70.368°S) in the South Pole-Aitken Basin. By comparison, the DEM model of Chang'E-1 is better than the USA ULCN2.05 in accuracy and resolution and is probably identical to the DEM of Japan SELENE, but the DEM of Chang'E-1 reveals a new lowest point, clearly lower than that of SELENE.

关键词： Chang’E-1 laser altimetry lunar DEM topographic tops of the Moon