检索结果-南通市图书馆

Characteristics and geological significance of olivine xenocrysts in Cenozoic volcanic rocks from western Qinling

在线全文

学校读者我要写书评

暂无评论

Progress in natural Science:Materials International 2006年第12期16卷 1300-1306页

作者： SU Benxun~ 1.2.**, ZHANG Hongfu~1. XIAO Yan~ 1.2.and zhao Xinmiao~ 1.2.(1. State Key Laboratory of Lithospheric Evolution, institute of Geology and Geophysics,{2., beijing 1.002., china 2. Graduate School of{2., beijing 1.0039, china) State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China Graduate School of chinese academy of sciences Beijing 100039 China

Cenozoic volcanic rocks from the Haoti, Dangchang County of the western Qinling Mountains, contain a few clearly-zoned olivines. These olivines are relatively big in grain sizes and usually have cracks or broken features. Their cores have similar compositions （Mg#=90.4-91.0） to those for the peridotitic xenoliths entrained in host volcanic rocks and their rims are close to the compositions of olivine phenocrysts （Mg#=85.5-81.9）. The CaO contents in these zoned olivines are lower than 0.1.. These features demonstrate that the clearly-zoned olivines are xenocrysts and disaggregated from mantle peridotites. The zoned texture was the result of the interaction between the olivine and host magma. Available data show that the volcanic rocks would have been derived from the mantle source metasomatized by subducted hydrathermally-altered oceanic crust. The formation of these Cenozoic volcanic rocks was perhaps related to the rapid uplift of the Tibetan Plateau.

关键词： Western Qinling Dangchang Haoti Cenozoic volcanic rocks olivine xenocrysts zoned texture.

Analysis and Modeling on the Spatial Structure of Urban Land Use: A Case of Jinan, china

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

chinese Journal of Population,{1. and Environment 2007年第2期5卷 34-40页

作者： zhao Huixia1, 3, Zhang Zulu2. Jiang Luguang 1 1. institute of Geographical {2. and natural resources research, chinese academy of sciences, beijing 100101, china 2. College of Population, resources and Environment, Shandong Normal University, Jinan Shandong 2.0014, china 3. Graduate School of the chinese academy of sciences, {12. 100039, china institute of Geographical {1. and {2. resources research Chinese Academy of Sciences Beijing 100101 China Graduate School of the chinese academy of sciences Beijing 100039 China College of Population Resources and Environment Shandong Normal University Jinan Shandong 250014 China

Based on the data of urban land use obtained by remote sensing interpretation from aero images in 1.86 and 2.04, the spatial structure of Jinan is studied in this paper with the method of Geographic Information System (GIS). According to the proportion of land for residence, industry and commerce, the urban district can be distinguished into three rings. Compared with the traditional theory of the ring structure in Western coun- tries, they have many distinctive characteristics. The main func- tions of the inner ring include residence, business and banking, but the proportion of residential land (more than 50%) is considerably higher than that of the cities in Western countries. The land proportion for residence and industry in the intermediate ring is equal on the whole. The main land of the outside ring is for industrial use. From 1.86 to 2.04, great changes have taken place on the land proportion of different types of use. In the inner ring, the land for residential and industrial use has shrunk much while the land for commercial use has increased. In the intermediate ring, the changes of the three types of land use were not very much and the temporal variation was relatively stable. On the contrary, the structure in the outside ring varies acutely. Though most of it is also for industrial use, the proportion of residential land has in- creased much. The three rings can also be divided into several sectors respectively, according to the function of land use clusters. New trends and mechanisms of the changes of land use impacting the urban structure were proposed in the end of the paper.

关键词： urban land use ring structure sector structure Jinan

Statistical distribution of nonlinear random wave height

在线全文

学校读者我要写书评

暂无评论

Science china Earth {1. 2006年第4期49卷 443-448页

作者： HOU Yijun1, GUO Peifang1,2. SONG Guiting1,2. SONG Jinbao1, YIN Baoshu1 & zhao Xixi1,2.1. institute of Oceanology,{2., Qingdao 2.6071, china 2. Graduate University of the{2., beijing 100039, china institute of Oceanology Chinese Academy of Sciences Qingdao China Graduate University of the chinese academy of sciences Beijing China

A statistical model of random wave is developed using Stokes wave theory of water wave dynamics. A new nonlinear probability distribution function of wave height is presented. The results indicate that wave steepness not only could be a parameter of the distribution function of wave height but also could reflect the degree of wave height distribution deviation from the Rayleigh distribution. The new wave height distribution overcomes the problem of Rayleigh distribution that the prediction of big wave is overestimated and the general wave is underestimated. The prediction of small probability wave height value of new distribution is also smaller than that of Rayleigh distribution. Wave height data taken from East china Normal University are used to verify the new distribution. The results in- dicate that the new distribution fits the measurements much better than the Rayleigh distribution.

关键词： Random ocean wave, nonlinearity, wave height distribution.

Plus cupping degrees do not form an ideal

在线全文

学校读者我要写书评

暂无评论

Science in china(Series F) 2004年第5期47卷 635-654页

作者： LI Angsheng1.2.& {1. Yicheng1.1. institute of Software,{2. academy of sciences,beijing 1.0080,china 2. School of Information sciences,beijing Normal University,beijing 1.0871.china institute of Software Chinese Academy of Sciences Beijing China School of Information sciences Beijing Normal University Beijing China

A computably enumerable (c.e.,for short)degree a is called plus cupping,if every c.e. degree x with 0 详细信息

A computably enumerable (c.e.,for short)degree a is called plus cupping,if every c.e. degree x with 0

关键词： computably enumerable set Turing degree definability.

Petrogenesis and dating of the Kangding complex,Sichuan Province

在线全文

学校读者我要写书评

暂无评论

Science china Earth {1. 2005年第5期48卷 622-634页

作者： CHEN Yuelong 1 , LUO zhaohua 1 , zhao Junxiang, LI Zhihong, ZHANG Hongfei & SONG Biao 3 1. Faculty of Earth {2. and natural resources, china University of Geo{2., beijing 100083, china 2. Faculty of Earth {2., china University of Geo{2., Wuhan 430074, china 3. beijing SHRIMP Center, institute of Geology, chinese academy of Geological {2., beijing 100037, china Faculty of Earth sciences and {1. {2. China University of Geosciences Beijing China Faculty of Earth sciences China University of Geosciences Wuhan China beijing SHRIMP Center Institute of Geology Chinese Academy of Geological Sciences Beijing China

An analysis of major and trace element geochemistry and SHRIMP U-Pb zircon dating of mafic, intermediate, and felsic rocks from the Mianning metamorphic complex of Si- chuan Province was conducted. One of our conclusions is that a majority of the zircons crystal- lized between 72. and 773 Ma in a magmatic regime. The complexes contain early to late Pa- leo-proterozoic relict zircons from ancient continental crust. The oldest age, 2.68 Ma, may rep- resent the basement of the Yangtze block. Overgrowth zircon rims and palingenetic zircons have been observed and dated, and are believed to have formed after crystallization, during Paleozoic and Mesozoic metamorphic-anatexis. We also conclude that depletion of Nb, Ta, HREE, in a spider-diagram normalized to primitive mantle and calc-alkaline association, implies that they formed in island-arc or under-plating settings.

关键词： Kangding complex, zircons, SHRIMP, tectonic setting.

Transient species and its properties of melatonin

在线全文

学校读者我要写书评

暂无评论

Science china Chemistry 2006年第4期49卷 308-314页

作者： ZHU Hongping1,2. ZHANG zhaoxia1,2. zhao Hongwei1, WANG Wenfeng1 & YAO Side1 1. Shanghai {2. of Applied Physics, chinese academy of sciences, Shanghai 2.1800, china 2. Graduate University of the chinese academy of sciences, beijing 100049, china Shanghai institute of Applied Physics Chinese Academy of Sciences Shanghai China Graduate University of the chinese academy of sciences Beijing China

The photo-physical and photo-chemical properties of melatonin (ML) werestudied by 2.6 nm laser flash photolysis (LFP). ML undergoes photo-ionization to produce radicalcation of ML (ML^(·+))and hydrated electrons (e_(aq)^-), while excited triplet state ~3ML~* is alsoformed during photolysis. The oxidation via one electron transfer from ML to SO_4^(·+) and thetriplet state of riboflavin (~3RF~*) has been also investigated and the rate constants for theprocess have been determined to be 8.0x1.^9 and 1.4x1.^9 L·mol^(-1.·s^(-1. respectively. Theradical cation of 2.2.'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid)(ABTS^(·+)) scavengingcapacities of melatonin and other antioxidants are compared in this paper.

关键词： melatonin, laser flash photolysis, photoionization, triplet state.

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 {1.) 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 institute of Remote Sensing Applications of{2. and beijing Normal University,beijing 100101,china 2.Graduate School of the{2.,beijing 100049,china 3 research institute of Forest {12. and Information Techniques,chinese academy of Forestry,beijing 10009,china 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 China Graduate School of the chinese academy of sciences Beijing China research {1. of Forest {2. and Information Techniques Chinese Academy of Forestry Beijing China

The estimation of above-ground biomass(AGB) and carbon storage is very important for arid and semi-arid ***-1./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 1. 799 2.0 t,which has greatly contributed to the carbon fixation in northern{1..

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

A Subdivision-Based Combined Shape and Topology Optimization in Acoustics

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & sciences 2024年第4期139卷 847-872页

作者： chuang Lu Leilei Chen {1. Luo Haibo Chen CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern MechanicsUniversity of Science and Technology of ChinaHefei230027China College of Intelligent Construction Wuchang University of TechnologyWuhan430223China Henan International Joint Laboratory of Structural Mechanics and Computational Simulation School of Architecture and EngineeringHuanghuai UniversityZhumadian463000China beijing Aerospace Technology {1. Beijing100074China

We propose a combined shape and topology optimization approach in this research for 3D acoustics by using the isogeometric boundary element method with subdivision *** existing structural optimization methods mainly contain shape and topology schemes,with the former changing the surface geometric profile of the structure and the latter changing thematerial distribution topology or hole topology of the *** the present acoustic performance optimization,the coordinates of the control points in the subdivision surfaces fine mesh are selected as the shape design parameters of the structure,the artificial density of the sound absorbing material covered on the structure surface is set as the topology design parameter,and the combined topology and shape optimization approach is established through the sound field analysis of the subdivision surfaces boundary element method as a *** topology and shape sensitivities of the approach are calculated using the adjoint variable method,which ensures the efficiency of the *** geometric jaggedness and material distribution discontinuities that appear in the optimization process are overcome to a certain degree by the multiresolution method and solid isotropic material with *** examples are given to validate the effectiveness of the presented optimization approach.

关键词： Subdivision surfaces boundary element method topology optimization shape optimization combined optimization

Variation properties of ionospheric eclipse factor and ionospheric influence factor

维普期刊数据库评论

在线全文

维普期刊数据库

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 573-576页

作者： zhao Chunmei 1.{1.*, YUAN Yunbin1. OU Jikun1.and CHEN Jinping3(1. institute of Geodesy and Geophysics,{{1., Wuhan 430077, china {1. Graduate School of{{1., beijing 1.0039, china 3. Department of Precision Instrument and Mechanology, Tsinghua University, beijing 1.0084, china) institute of Geodesy and Geophysics Chinese Academy of Sciences Wuhan 430077 China Graduate School Chinese Academy of Sciences Beijing 100039 China Department of Precision Instrument and Mechanology Tsinghua University Beijing 100084 China

The concepts and calculation methods of ionospheric eclipse factor (IEF) and ionospheric influence factor (IFF) are further illustrated. The temporal and spacial variation properties of IEF and IFF are studied, which shows that the properties are influenced by the geographic position and season. The possibility of improving the precision of using GPS data to determine ionospheric delay based on the above variation properties is also analysed.

关键词： GPS Ionospheric eclipse factor Ionospheric influence factor