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The evaluation of interregional status and development proposals of Chongqing

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Journal of geographical Sciences 1998年第3期8卷 74-82页

作者： XU guanghong LU Dadao institute of geography, Chinese Academy of Sciences, Beijing 100101 china

As the fourth municipality directly under the Central government, there exist some economic development obstacles including dual economic structures and regional development disparity in Chongqing. According to the local position, economic basis and technical superiority, Chongqing should be an economic growth pole in the interior of china so that it is necessary to evaluate its interregional status. Although the position of economic strength is generally among all of the administrative divisions, the position of Chongqing is very prominent between Southwest china and the Yangtze River industrial zone. In order to give play to the spread action of a growth pole and to promote regional economic coordinated development of the Central and Western part of china, Chongqing should adopt the regional sustained and rapid development strategy. Correspondingly, a series of development proposals has also been put forward in the paper.

关键词： regional development interregional status Chongqing

The developmental trend of labrum and median eyes of Orsten-type preserved Phosphatocopina (Crustacea)

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Science china Earth Sciences 2010年第1期53卷 18-26页

作者： LIU Zheng 1,2 & DONg XiPing 1,2 1 School of Earth and Space Sciences,Peking University,Beijing 100871,china 2 State Key Laboratory of Palaeobiology and Stratigraphy,Nanjing institute of g.olog. and Palaeontology,Chinese Academy of Sciences,Nanjing 210008,china School of Earth and Space Sciences Peking University Beijing China State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing China

The Phosphatocopina (Crustacea,Arthropoda) is an important group of 'Orsten-type' preserved *** is resolved as the sister-group of *** we study the labrum,the median eyes,and the inner lamella of Phosphatocopina based on the selected specimens respectively from western Hunan,South china,and *** labrum characters of different species exhibit interspecific *** ratio of labrum length/shield length is significant to the reconstruction of the ontogeny of *** labrum characters should be introduced to the diagnosis of *** the earliest growth stage,the median eyes were inconspicuous,almost as flat as the other area of the ***,with the growth of the individuals they became *** were two obviously concave structures on the ventral side of the hypostome in later stages,which were the positions where the median eyes should have been *** addition,the two modes of preservation of the inner lamella,i.e.,that of shrinking and that of bulging up,are interpreted as the preservational artifact herein.

关键词： Phosphatocopina Crustacea Orsten-type preservation morphology ontogeny Cambrian South china Sweden

Tree wavelet approximations with applications

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Science china Mathematics 2005年第5期48卷 680-702页

作者： XU Yuesheng & ZOU Qingsong Department of Mathematics, Syracuse University, Syracuse, NY 13244, USA institute of Mathematics, Academy of Mathematics and System Sciences, Chinese Academy of Sciences, Beijing 100080, china Department of Scientific Computing and Computer Science, Zhongshan University, guangzhou 510275, china Department of Mathematics Syracuse University Syracuse USA institute of Mathematics Academy of Mathematics and System Sciences Chinese Academy of Sciences Beijing China Department of Scientific Computing and Computer Science Zhongshan University Guangzhou China

We construct a tree wavelet approximation by using a constructive greedy scheme (CgS). We define a function class which contains the functions whose piecewise polynomial approximations generated by the CgS have a prescribed global convergence rate and establish embedding properties of this class. We provide sufficient conditions on a tree index set and on bi-orthogonal wavelet bases which ensure optimal order of convergence for the wavelet approximations encoded on the tree index set using the bi-orthogonal wavelet bases. We then show that if we use the tree index set associated with the partition generated by the CgS to encode a wavelet approximation, it gives optimal order of convergence.

关键词： greedy algorithms tree wavelet approximations Besov spaces.

Human activity response and prevention strategies on soil and water loss in Sichuan Province

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Science china(Technological Sciences) 2003年第Z1期46卷 91-109页

作者： FANg Yiping & CHEN guojie institute of Mountain Hazards and Environment, Chinese Academy of Sciences and Ministry of Water Resources, Chengdu 610041, china Chinese Acad Sci Inst Mt Hazards & Environm Chengdu 610041 Peoples R China Minist Water Resources Chengdu 610041 Peoples R China

Ten major factors have been selected to judge the degree of disturbance from human activity and the corresponding relationship of the impact on soil and water loss in Sichuan Province. Correlation analysis has demonstrated that stock-carrying capacity, percentage of land reclamation, population density, gDP per capita, mineral modulus and percentage of forest coverage are the 6 most relevant human activity factors. The analysis on the degree of disturbance has shown that population pressure, excessive or unreasonable activities in development of resources and destructive behavior of humans are the main causes of soil and water loss. Consequently, solving the various problems in the negative activity of humans and regulating human behavior are the first tasks that should be tackled in the conservation of water and soil. In the new era, the prevention and rectification of soil and water loss are measures based on the foundation of the ecosystem, which is a kind of management strategy for sustainable development. The foundation of this method is made up of the system innovations and breakthroughs in terms of aims, philosophy, measures, and aspects of the prevention and rectification of soil and water loss, simultaneous advance from the conceptual, policy, spatial, technical and mode levels and system integration on the treatment strategies.

关键词： Sichuan, degree of disturbance, soil and water loss, system innovation.

Multi-Step Amplitude Quantization for Ultralow Sidelobe Phased Arrays by Direct Optimization Synthesis

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Journal of Systems Engineering and Electronics 2001年第1期12卷 65-69页

作者： Zhu Huan Wang Yixin Xu Xiaowen & Li Shizhi Dept. of Electronic Engineering, Beijing institute of Technology, 100081, P. R. china Dept. of Electronic Engineering Beijing Institute of Technology 100081 P. R. China

In this paper, a new amplitude quantization synthesis method for ultralow sidelobe phased arrays is proposed, which is based on the constrained nonlinear optimization algorithm. By introducing a set of critical constraint conditions into the optimization model, we can directly quantize the amplitude distribution instead of replacing it with a continuous equivalent aperture antenna. The mutual coupling and the element patterns are also considered in the quantization synthesis. Finally, some array simulation results are given to show the effectiveness of the method.

关键词： Algorithms Computer simulation Directional patterns (antenna) Directive antennas Mathematical models Optimization Vector quantization

MICROSTRUCTURE OF SILICON CARBIDE WHISKERS

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Acta Metallurgica Sinica(English Letters) 1991年第9期4卷 211-218页

作者： XU Haigang ZHU Jing YUAN Hong Central Iron and Steel Research institute,Ministry of Metallurgical Industry,Beijing,chinaNINg Xiaoguang YE Hengqiang Laboratory of Atomic Imaging of Solids,institute of Metal Research,Academia Sinica,Shenyang,china Central Iron and Steel Research Inst Beijing China

The morphology,crystal defects and chemical compositions of surfaces in two kinds of SiC whiskers related to their growth mechanism have been studied by means of electron microscopy and surface chemical *** upon the experimental results,five criteria for evaluating the whisker microstructure were suggested as:proportion of the perfect single crystals,morphology and dimensions,defects and their distribution,the bulk and surface chemistries,and crystallographic characteristics.

关键词： SiC whisker microstructure defect

Present Situation and Prospects of High-purity Elements in china

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Rare Metals 1992年第3期11卷 228-231页

作者： Zhang Weihuo Emei Semiconductor Material Research institute.Emei 614200,china

***-purity elements are the basic materials in electronics,communication,aerospace,atomicenergy and semiconductor material *** development is a decisive factor for high-tech *** high-purification of non-ferrous metals... 详细信息

关键词： high CdTe In gaAs Present Situation and Prospects of High-purity Elements in china

SHRIMP U-Pb dating and Hf isotopic analyses of Middle Ordovician meta-cumulate gabbro in central Qiangtang, northern Tibetan Plateau

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Science china Earth Sciences 2010年第5期53卷 657-664页

作者： ZHAI Qingguo1 WANg Jun1, LI Cai2 & SU Li3 1 institute of g.olog., Chinese Academy of g.olog.cal Sciences, Beijing 100037, china 2 College of Earth Sciences, Jilin University, Changchun 130061, china 3 The g.olog.cal Laboratory Center and State Key Laboratory of g.olog.cal Processes and Mineral Resources, china University of geo- sciences, Beijing 100083, china institute of g.olog. Chinese Academy of Geological Sciences Beijing China College of Earth Sciences Jilin University Changchun China The g.olog.cal Laboratory Center and State Key Laboratory of g.olog.cal Processes and Mineral Resources China University of Geosciences Beijing China

Metabasites consisting of metamorphic ultra-mafic rocks, cumulate gabbro, gabbro (diabase), basalt, and plagiogranite are exposed at the Taoxinghu area in central Qiangtang, northern Tibetan Plateau. Zircon SHRIMP U-Pb dating for the cumulate gabbro yields a weighted mean age of 467±4 Ma, which is the oldest and most reliable magmatic age in this area. Zircon 176Hf/177Hf ratios range from 0.282615 to 0.282657, with εHf(t) values of 5.02±0.28, indicating that the cumulate gabbro was mainly derived from the depleted mantle. In addition, geochemical data of metabasites suggest that they have similar characteristics to those in the mid-ocean ridge basalts (MORB). The Taoxinghu metabasites may represent the fragment of Early Paleozoic ophiolite in the "Central Uplift" of the Qiangtang, northern Tibetan Plateau.

关键词： Qiangtang cumulate gabbro SHRIMP dating Hf isotope

Absolute scaling law for temperature data in Rayleigh-Benard convection

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Science china(Technological Sciences) 2009年第3期52卷 684-687页

作者： FU Qiang Research Center of Fluid Mechanics, institute of Science of, People’s Liberation Army University of Science and Technology, Nan- jing 211101, china Research Center of Fluid Mechanics Institute of Science of People’s Liberation Army University of Science and Technology Nanjing China

In addition to the hierarchical-structure (H-S) model, this paper further explores the most intensive intermittent structure of Rayleigh-Bénard convection at the high Ra numbers proportional to temperature. With respect to the discovery and by means of the scale, both of Bolgiano, there are two regions of the structure holding the absolute scaling law given by Ching’s paper. Through theoretic analysis of data, this paper indicates that the regions act as two local intensive intermittent structures, by which the statistical absolute scaling performance of region is induced, rather than the statistical result of the entire time series in belief since 1941. In terms of statistical theory, the local structure in fluid, therefore, is the essence governing the absolute scaling performance of region, especially in high intensity.

关键词： Rayleigh-Benard convection Bolgiano scale the most intensive structure absolute scaling law local structure