检索结果-南通市图书馆

Experimental study of ore gabbro liquid immiscibility

在线全文

学校读者我要写书评

暂无评论

Science China Earth sciences 2005年第4期48卷 496-505页

作者： SANG Zunan1,2, XIA Bin1, ZHOU Yongsheng3.& JIN Zhenmin4 1. Guangzhou institute of Geochemistry, chinese academy of sciences, Guangzhou 510640, China 2. Wuhan University, Wuhan 43.072, China 3. institute of Geology, China Seismological Bureau,{3. 100029, China 4. Faculty of Earth sciences, China University of Geosciences, Wuhan 43.074, China 1. Guangzhou institute of Geochemistry Chinese Academy of Sciences 510640 Guangzhou China 2. Wuhan University 430072 Wuhan China 3. institute of Geology China Seismological Bureau 100029 Beijing China 4. Faculty of Earth sciences China University of Geosciences 430074 Wuhan China

In this paper, the authors present the results of a preliminary experimental study on partial melting of fine-grained gabbro, Panzhihua, Sichuan Province, China. Experiments were conducted under (confining) pressure ranging from 450 to 500 MPa and temperature of 900— 1200℃. The results show that the initial melt is distributed along grain boundaries and triple junctions. Liquid immiscibility phenomena are noted in the melt with two compositional different melt phases, i.e. matrix and sphere phases. The matrix phase is relatively rich in Si, Al and K, and is depleted in Mg, Fe, Ca, Na and Ti, whereas the sphere phase shows opposite trends. The calculation of the melt free energy indicates that the liquid immiscibility is governed by the rule of thermodynamics, as the liquid immiscibility would result in the decrease in free energy of the melt system. The field relationships suggest that the liquid immiscibility may have played an important role in the generation of ore magma of Panzhihua V-Ti magnetite ore deposit. This study thus provides experimental constraints on the mechanism of the formation of V-Ti magnetite deposite.

关键词： partial melting, experimental study, gabbro, liquid immiscibility, ore formation mechanism.

Concatenating construction of the multisymplectic schemes for 2+1-dimensional sine-Gordon equation

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2004年第1期47卷 18-30页

作者： WANG Yushun, WANG Bin & QIN MengzhaoLASG, institute of Atmospheric Physics, chinese academy of sciences, beijing 100029, China School of Mathematics and Computer Science, Nanjing Normal University, Nanjing 210097, China School of Mathematics and System Science, chinese academy of sciences, beijing 100080, China 1. LASG Institute of Atmospheric Physics Chinese Academy of Sciences 100029 Beijing China 2. School of Mathematics and Computer Science Nanjing Normal University 210097 Nanjing China 3. School of Mathematics and System Science Chinese Academy of Sciences 100080 Beijing China

In this paper, taking the 2+1-dimensional sine-Gordon equation as an example, we present the concatenating method to construct the multisymplectic schemes. The method is to discretizee independently the PDEs in different directions with symplectic schemes, so that the multisymplectic schemes can be constructed by concatenating those symplectic schemes. By this method, we can construct multisymplectic schemes, including some widely used schemes with an accuracy of any order. The numerical simulation on the collisions of solitons are also proposed to illustrate the efficiency of the multisymplectic schemes.

关键词： 2+l-climensional sine-Gordon equation multisymplectic scheme concatenating method solitons

GENETIC DIVERSITY AMONG chinese SIKA DEER (CERVUS NIPPON) POPULATIONS AND RELATIONSHIPS BETWEEN chinese AND JAPANESE SIKA DEER

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 2006年第4期51卷 433-440页

作者： Lü Xiaoping WEI Fuwen LIMing YANG Guang LIU Hai Key Laboratory for Animal Ecology and Conservation Biology Insti-tute of Zoology Chinese Academy of Sciences Beijing 100080China Graduate School of the chinese academy of sciences Beijing 100039China institute of Genetic Resources Nanjing Normal University Nanjing 210097 China

Sika deer (Cervus nippon) is a cervid endemic to mainland and insular Asia and endan-gered. We analyzed variation in the mitochondrial DNA (mtDNA) control region for four subspecies to understand the genetic diversity, population structure and evolutionary history in China. 3.5 bp were se-quenced and eight haplotypes were identified based on 25 variable sites among the populations. Sika deer in China showed lower genetic diversity, sug-gesting a small effective population size due to habi-tat fragmentation, a low number of founder individu-als, or the narrow breeding program. AMOVA analy-sis indicated that there was significant genetic subdi-vision among the four populations, but no correlation between the genetic and geographic distance. Phy-logenetic analyses also revealed that chinese sika deer may be divided into three genetic clades, but the genetic structure among chinese populations was inconsistent with subspecies designations and pre-sent geographic distribution. Including the sequence data of Japanese sika deer, the results indicated that chinese populations were more closely related to Southern Japanese populations than to the Northern Japanese one, and the Taiwan population was closer to populations of Northeastern China and Sichuan than to those of Southern China.

关键词：中国梅花鹿遗传多样性衔接重复数量日本梅花鹿

Prediction of Debris-flow Danger Area by Combining Hydrological and Inundation Simulation Methods

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2011年第1期8卷 1-9页

作者： CUI Peng Key Laboratory of Mountain Hazards and Earth Surface Process Chinese Academy of Sciences Chengdu 610041 China institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China Graduate School of chinese academy of sciences Beijing 100049 China

Debris flows have caused serious human casualties and economic losses in the regions strongly affected by the Ms8.0 Wenchuan earthquake of 2oo8. Debris flow mitigation and risk assessment is a key issue for reconstruction. The existing methods of inundation simulation are based on historical disasters and have no power of prediction. The rain- flood method can not yield detailed flow hydrograph and does not meet the need of inundation simulation. In this paper, the process of water flow was studied by using the Arc-SCS model combined with hydraulic method, and then the debris flow runoff process was calculated using the empirical formula combining the result from Arc-SCS. The peak discharge and runoff duration served as input of inundation simulation. Then, the dangerous area is predicted using kinematic wave method and Manning equation. Taking the debris flow in Huashiban gully in Beichuan County, Sichuan Province, China on 24 Sep. 2oo8 as example, the peak discharge of water flow and debris flow were calculated as 3..52 m3.s-1 and 215.66 m3.s-, with error of 4.15% compared to the measured values. The simulated area of debris-flow deposition was 161,500 m2, vs. the measured area of 144,097 m2, in error of 81.75%. The simulated maximum depth was 12.3.m, consistent with the real maximum depth between lO and 15 m according to the field survey. The minor error is mainly due to the flow impact on buildings and variations in cross-section configuration. The present methodology can be applied to predict debrisflow magnitude and evaluate its risk in other watersheds inthe earthquake area.

关键词： Debris flow Arc-SCS model Inundation simulation Risk analysis Wenchuan earthquake

A template of rat brain based on fMRI T2* imaging

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2005年第6期15卷 502-506页

作者： HU Zhenghui1, WU Yigen2, WANG Xiaochuan3. WANG Jianzhi3. CHEN Feiyan1 and TANG Xiaowei1*(1. Department of Physics and Bio-X Laboratory, Zhejiang University, Hangzhou 3.0027, China 2. institute of High Energy Physics and Key Laboratory of Nuclear Analysis Techniques, chinese academy of sciences,beijing 10003., China 3. Department of Pathophysiology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 43.03., China) Department of Physics and Bio-X Laboratory Zhejiang University Hangzhou 310027 China institute of High Energy Physics and Key Laboratory of Nuclear Analysis Techniques Chinese Academy of Sciences Beijing 100039 China Department of Pathophysiology Tongji Medical College Huazhong University of Science and Technology Wuhan 430030 China

The development of functional magnetic resonance imaging (fMRI) technology has made it possible to carry out functional brain imaging experiments in small animals. Usually, group data is required to form the assessment of population, which can not only increase the sensitivity of the overall experiment, but also allow the generalization of the conclusion to the whole population. In order to average the signals of functional brain images from different subjects, it is necessary to put all the mapping images into the same standard space (template image). However, up to now, most animal brain templates remain unavailable and it must be done by ourselves. In this study, a template image based on the brains of eight male Wistar rats is obtained, and it is successfully used in our present Alzheimer disease (AD)-like rat model studies as template for spatially normalizing images to the same stereotaxical space. The fMRI results processed with statistical parametric mapping (SPM99) software are in agreement with the results from immunohistochemical experiment, which proves that this method is universally applicable to the pathologic models of other small animals and to human brain lesion studies.

关键词： fMRI animal model atlas template normalization T*2.

GLIVENKO-CANTELLI TYPE THEOREMS ANDTHEIR APPLICATIONS

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematica Scientia 1997年第3期17卷 309-318页

作者：朱力行 ACAD SINICA INST APPL MATHPROBABIL LABBEIJING 100080PEOPLES R CHINA

In this paper, we present a sufficient condition for uniform convergence of means to their expectations over the classes of real functions. Our proof is very simple via connecting this convergence to uniform convergence over the class of indicator functions. Furthermore, we obtain a convergent result concerning a non=VC class with an application to variable transformation for fitting regression model.

关键词： uniform convergence non-VC class of functions variable transformation method

Thresholds of geographic environmental elements in sediment yield of drainage basins

在线全文

学校读者我要写书评

暂无评论

Science China Earth sciences 2005年第2期48卷 230-240页

作者： CHEN Hao, ZHOU Jinxing, CAI Qiangguo, LU Zhongchen & LI Zhongyan institute of Geographic sciences and Natural Resources Research, chinese academy of sciences,{3. 100101, China institute of Forestry Science, chinese academy of Forestry Science,{3. 100091, China Research Center for Eco-Environment sciences, chinese academy of sciences,{3. 100085, China Computing institute of Science and Engineering, North China Electric Power University,{3. 102206, China 1. institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences 100101 Beijing China 2. institute of Forestry Science Chinese Academy of Forestry Science 100091 Beijing China 3. Research Center for Eco-Environment sciences Chinese Academy of Sciences 100085 Beijing China 4. Computing institute of Science and Engineering North China Electric Power University 102206 Beijing China

Threshold of environmental elements in drainage basin sediment yield refers to, under effect of climate, underlying surface and human activity, a turning point of abrupt changes in drainage sediment yield related to environmental element characteristics. Previous studies on threshold of sediment yield of relevant drainage basins were mainly concentrated on impact of natural zones with a few researches on impact of other environmental elements. Particularly studies on compound environmental element threshold in drainage basin sediment yield remain blank today. Studies indicate that sediment yield in drainage basins is affected by compound interactions and complex actions. Based on single element analysis, the present paper gives quantitatively compound threshold of environmental elements affecting sediment yield of the drainage basin between Hekouzhen and Tongguan in the middle Yellow River by the method of multi-variant, polynomial formula regression analysis.

关键词： middle Yellow River, environmental element, sediment, sediment delivery mudule, threshold.

ON THE SOLVABILITY OF GENERAL LINEAR METHODS FOR DISSIPATIVE DYNAMICAL SYSTEMS

在线全文

学校读者我要写书评

暂无评论

Journal of Computational Mathematics 2000年第6期18卷 633-638页

作者： Ai-guo Xiao (Department of Mathematics, Xiangtan University, Xiangtan 411105, China.) (institute of Computational Mathematics and Scientific/Engineering Computing, chinese academy of sciences, beijing 100080, China) 湘潭大学湖南湘潭 4111105

The main purpose of the present paper is to examine the existence and local uniqueness of solutions of the implicit equations arising in the application of a weakly algebraically stable general linear methods to dissipative dynamical systems, and to extend the existing relevant results of Runge-Kutta methods by Humphries and Stuart(1994). [ABSTRACT FROM AUTHOR]

关键词： general linear methods dissipative dynamical systems weak algebraic stability solvability

Spectroscopic Measurements of Physiological Elements in Microdialysis Samples from Rat Brain,Flowering Plum Fruit and Pea

在线全文

学校读者我要写书评

暂无评论

chinese Chemical Letters 1999年第3期10卷 243-246页

作者： Hut Min MA Zhi Hua WANG Yi ZENG Hut Wan HAN Guo Quan LIU(institute of Chemistry,chinese academy of{3.,beijing 100080) chinese Acad Sci Inst Chem Beijing 100080 Peoples R China

The basal levels of magnesium and copper in rat brain and flowering plum fruit dialysates, and the background concentration of calcium in pea dialysates have been determined with sensitive spectroscopic techniques including atomic absorption spectrometry and spectrophotometry based on amino G acid chlorophosphonazo. It is found that the magnesium level in flowering plum fruit dialysates is much lower than that in rat brain dialysates, indicating a considerable composition difference present between a plant dialysate and an animal one.

关键词： microdialysis spectroscopic methods physiological element analysis calcium magnesium copper