检索结果-南通市图书馆

Conformal isoparametric hypersurfaces with two distinct conformal principal curvatures in conformal space

在线全文

学校读者我要写书评

暂无评论

Science china Mathematics 2010年第4期53卷 953-965页

作者： NIE ChangXiong 1,2,LI TongZhu 3,HE YiJun 4 & WU ChuanXi 5 1 Faculty of Mathematics and Computer sciences,Hubei university,Wuhan 430062,china 2 school of Mathematical sciences,peking university,beijing 100871,china 3 Faculty of sciences,beijing Institute of Technology,beijing 100081,china 4 school of Mathematical sciences,Shanxi university,Taiyuan 030006,china 5 Institute of Mathematics,Hubei university,Wuhan 430062,china Faculty of Mathematics and Computer sciences Hubei University Wuhan China school of Mathematical sciences Peking University Beijing China Faculty of sciences Beijing Institute of Technology Beijing China school of Mathematical sciences Shanxi University Taiyuan China Institute of Mathematics Hubei University Wuhan China

The conformal geometry of regular hypersurfaces in the conformal space is *** classify all the conformal isoparametric hypersurfaces with two distinct conformal principal curvatures in the conformal space up to confor... 详细信息

关键词： Lorentz conformal geometry conformal invariants conformal isoparametric hypersurfaces

An Early Cretaceous Avialian Bird, Shenzhouraptor sinensis from Western Liaoning, china

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2003年第1期77卷 21-27页

作者： Ji Qiang, Ji Shu’an, You Hailu, Zhang Jianping,Zhang Hongbin, Zhang Nanjun, Yuan Chongxi and Ji XinxinDepartment of earth sciences, Nanjing university, Nanjing, Jiangsu 100093Institute of Geology, Chinese Academy of Geological sciences, beijing 100037 school of earth and space sciences, peking university, beijing 100871china university of Geosciences, beijing 100083 china Dinosaur Park of Changzhou, Changzhou, Jiangsu 213002 Nanjing Univ Dept Earth Sci Nanjing 100093 Jiangsu Peoples R China Chinese Acad Geol Sci Inst Geol Beijing 100037 Peoples R China peking Univ Sch Earth & Space Sci Beijing 100871 Peoples R China china Univ Geosci Beijing 100083 Peoples R China china Dinosaur Pk Changzhou Changzhou 213002 Jiangsu Peoples R China

This paper describes an avialian bird from the Early Cretaceous JiufotangFormation in Yixian county, western Liaoning china, which is named as Shenzhouraptor sinensis by Jiet al. on July 15, 2002. Shenzhouraptor sinensis is characterized by no teeth in its mouth, theforelimbs longer than the hindlimbs, a long tail with more than 23 caudal vertebrae, U-shapedwishbone, and remiges longer than the total length of ulna and manus. It is certain that the newavialian bird is really capable of powerful flight, representing a missing link between theropoddinosaurs and birds.

关键词： Avialian birds Early Cretaceous Jiufotang Formation western Liaoning china

Chronological record of the Early Mesozoic underplating in the northern margin of North china—U-Pb chronometry of zircons in the Late Mesozoic andesite from Western Liaoning

在线全文

学校读者我要写书评

暂无评论

Progress in Natural Science:Materials International 2007年第8期17卷 943-947页

作者： Shao ji'an~(1,2**) Zhang Hongfu~2 Liu Xiaoming~3 Li Zhitong~4 (1.school of earth and space sciences,peking university,beijing 100871,china 2.Institute of Geology and Geophysics and Key Laboratory of Mineral Resources,Chinese Academy of sciences,beijing 100029,china 3.Key Laboratory of Continental Dynamics,Northwestern university,Xi'an 710069,china 4.Institute of Geology and Mineral Resources of Shenyang,Shenyang 110032,china) school of earth and space sciences Peking University Beijing 100871 China Key Laboratory of Mineral Resources Institute of Geology and Geophysics Chinese Acad. of Sci. Beijing 100029 China Key Laboratory of Continental Dynamics Northwestern University Xi'an 710069 China Institute of Geology and Mineral Resources of Shenyang Shenyang 110032 China

Cathodoluminescence spectroscopic analysis of zircons in the uppermost sanukites of the early Cretaceous Yixian Forma- tion in Western Liaoning reveals zoning structures of the zircons in the volcanic rocks. LA-ICP-MS chronometry shows that the central part of the zircons is remnant zircon with a U-Pb dating of 254 Ma,which is consistent with the age of the Early Mesozoic underplating granulites,and that the periphery is zircon crystallizing out of the host magma with a U-Pb dating of 116 Ma,which is highly consistent with the Ar-Ar dating of the host volcanic *** of the clinopyroxenes xenocrystals in the sanukites are similar to those of the clinopyroxenes in the underplating granulites,indicating that the granulites accreted to the lower crust in the Early Mesozoic have been reformed and disrupted by the upwelling diapers of the asthenosphere and taken part in formation of the sanukites in the Late Mesozoic.

关键词： northern margin of North china Mesozoic volcanic rock U-Pb chronometry of zircon underplating granulite

The role of aerial algae in the formation of the landscape of the Yunnan Stone Forest,Yunnan Province, 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

Science china earth sciences 2004年第9期47卷 846-864页

作者： TIAN Youping1,3, ZHANG Jie2, SONG Linhua1 & BAO Haosheng2 1. Institute of Geographic sciences and Natural Resources Research, Chinese Academy of sciences, beijing 100101, china 2. Department of Geography, Nanjing university, Nanjing 210093, china 3. school of earth sciences and Resources, china university of Geosciences, beijing 100083, china Institute of Geographic sciences and Natural Resources Research Chinese Academy of Sciences Beijing China school of earth sciences and Resources China University of Geosciences Beijing China Department of Geography Nanjing University Nanjing China

Aerial algae on the surface of carbonate rocks at the Stone Forest, Shilin County, Yunnan Province, china, and their bioerosion were investigated in the field and studied in the laboratory in detail. Through the observation, identification and statistics of more than one hun- dred algal samples and rock samples with the optical microscopes (stereomicroscope, biological microscope) and the scanning electronic microscope (SEM), the relationships between erosional forms on the surface of the Stone Forest and algae and/or algal communities and the genetic mechanism for the formation of erosional forms were analyzed. It is suggested that aerial algae play an active role in bioerosive processes that may affect the formation of karst erosional forms. These effects include both direct and indirect ones. The direct effect is the initiative control (algal shape-controlling role) of algae on the formation of karst forms of various scales, mostly mi- cro-scale (3m) and minor-scale (10-3-10-1m) erosional forms. The algal shape-controlling roles can be divided into the algal individual shape-controlling role and the algal community shape-controlling role. The former mostly controls the formation of micro-scale erosional forms, while the latter mostly controls the formation of micro-scale and smaller minor-scale erosional forms. The indirect effect refers to the promoting role of algae in the formation of karst forms, which may affect the formation of karst forms of all types and scales. The bioerosion of algae accelerates the weathering process of the whole Stone Forest karst landforms.

关键词： aerial algae, bioerosion, the Stone Forest, Yunnan Province, china.

On the local wellposedness of 3-D water wave problem with vorticity

在线全文

学校读者我要写书评

暂无评论

Science china Mathematics 2007年第8期50卷 1065-1077页

作者： Ping ZHANG~1 Zhi-fei ZHANG~2 1 Academy of Mathematics and Systems Science,Chinese Academy of sciences,beijing 100080,china 2 school of Mathematical sciences,peking university,beijing 100871,china Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing China school of Mathematical sciences Peking University Beijing China

In this article, we first present an equivalent formulation of the free boundary problem to 3-D incompressible Euler equations, then we announce our local wellposedness result concerning the free boundary problem in Sobolev space provided that there is no self-intersection point on the initial surface and under the stability assumption that $\frac{{\partial p}}{{\partial n}}(\xi )\left| {_{t = 0} } \right. \leqslant - 2c_0 < 0$ being restricted to the initial surface.

关键词： water-waves free boundary incompressible Euler equations primary 35Q35 76B03 secondary 35J67 35L80

Frontal genesis of moisture atmosphere during the early 2008 persistent freezing-rain event in southern china

在线全文

学校读者我要写书评

暂无评论

Science china earth sciences 2010年第3期53卷 454-464页

作者： QIAN WeiHong1 & FU JiaoLan1,2 1 Department of Atmospheric sciences, school of Physics, peking university, beijing 100871, china 2 National Meteorological Center of CMA, beijing, 100081, china Department of Atmospheric sciences School of Physics Peking University Beijing China National Meteorological Center of CMA Beijing China

From January 10 to February 2, 2008, a severe and persistent freezing-rain event occurred in southern and southwestern china. Here we use an observational analysis to compare the persistent freezing-rain event in the early 2008 with the winter precipita- tion in the late 2007 over south of the Yangtze River (Jiangnan). The persistent freezing-rain event was directly linked to the activity of quasi-stationary front. The gradient of equivalent temperature (ET) can well indicate the frontal genesis of moist atmosphere (moisture front) and its activity as well as its relationship with precipitation belt. The precipitation types (snow and freezing rains) are related to the vertical structure of moisture front. The inversion profile of ET vertical distribution is a typical synoptic condition that caused the freezing-rain event. The horizontal gradient of ET with a criterion of 10℃ / 100 km, which reflects the accumulation and release of atmospheric energy, can be applied to predict the precipitation 5-10 days in advance.

关键词： freezing-rain event frontal genesis extended-range weather forecast winter Jiangnan

Zhang-Xuan thermal uplift and its genesis

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8期15卷 725-732页

作者： SHAO Ji'an1*, NIU Shuyin2, ZHANG Lüqiao3 and LI Hongyang2(1. school of earth and space sciences, peking university, beijing 100871, china 2. Shijiazhuang university of Economics, Shijiazhuang 050031, china 3. Geological Bureau of Inner Mongolia, Huhhot 010020, china) school of earth and space sciences Peking University Beijing 100871 China Shijiazhuang university of Economics Shijiazhuang 050031 China Geological Bureau of Inner Mongolia Huhhot 010020 China

Based on the researches of the Mesozoic thermal evolution history, the deformed structures, and fission track analysis of the Zhangjiakou-Xuanhua area, we obtained the following knowledge: the area experienced in 140 Ma an underplating which is marked by emplacement of mantle derived magma; during 130—110 Ma a series of eruptions and intrusions happened, and during 80—10 Ma a rising process occurred which is synchronous with the adjacent Taihang and Yanshan Mountains and was accompanied by a series of structures down slipping from the just formed Zhang-Xuan uplift toward its periphery. Combining the Zhang-Xuan thermal lift with the large detachment structure in Baoding depression of the North china Basin in the Late Mesozoic confirms that an even larger extensional tectonic background existed in North china during this period.

关键词： Zhang-Xuan area underplating thermal uplift fission track extensional structure.

Decoupling of surface and subsurface sutures in the Dabie orogen and a continent-collisional lithospheric-wedging model: Sr-Nd-Pb isotopic evidences of Mesozoic igneous rocks in eastern 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 Science Bulletin 2003年第8期48卷 831-838页

作者： LI Shuguang & YANG Wei school of earth and space sciences, university of Science and Tech-nology of china, Hefei 230026, china school of earth and space sciences University of Science and Technology of China Hefei 230026 China

There are significant differences of Nd and Pbisotopic compositions between Mesozoic mafic igneous rocks from the North china Block (NCB) and the South chinaBlock (SCB). Mesozoic mantle-derived igneous rocks fromthe North china Block have very low e Nd values (-15 to -21), and 206Pb/204Pb ratios ( -10 and 206Pb/204Pb > 18.3. The verylow e Nd values (-16 to -20) and 206Pb/204Pb ratios (3) of the early Cretaceous mafic-ultramafic intrusions developedin the north part of the Dabie orogen (NDZ) suggest that the deep lithosphere underneath the NDZ belongs to the NCBbut not the SCB. Therefore, although the surface suture be-tween the NCB and SCB is located on the north side of theNDZ, the subsurface suture between the NCB and SCBshould be located to the south side of the NDZ. This is con-sistent with the previous suggestion that the subsurface su-ture in the Sulu terrane east of the Tanlu fault was the south displacement, but contradictory to northward continentalsubduction of the SCB. A continent-collisional lithospheric-wedging model can interpret the decoupling of the surface and subsurface sutures in the Dabie-Sulu orogen. After slabbreak-off, the continuing convergence of two continental blocks must increase the compression force acting on the suture zone, which might induce the lithosphere splitting of SCB. Thus, the lower crust and lithospheric mantle on thesouth margin of the NCB can wedge into the north margin of the lithosphere of the SCB along the Dabie-Sulu collisionzone. This process caused the overthrust of the mid-upper continental crust with exhumed ultrahigh pressure meta-morphic (UHPM) rocks and underthrust of the deep litho-sphere of the SCB. It could be an important mechanism re-sponsible for the second rapid cooling and uplifting of theUHPM rocks and lithospheric delamination as well as thecorresponding magmatism in Jurassic in the Dabie *** southward movement of subsurface suture

关键词：大别造山带同位素中生代火成岩中国

A study of the microbial mineralization in submarine black smoker chimneys from the Okinawa Trough

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2009年第2期28卷 87-95页

作者： FENG Jun LI Jianghai CHU Fengyou National earthquake Response Support Service China Earthquake Adiministration Beijing 100049 China school of earth and space sciences Peking University Beijing 100871 China Second Institute of Oceanography State Oceanic Administration Hangzhou 310012 China

Large amounts of microfossil records discovered in the seafloor black smoker chimney are reported from the Okinawa Trough. They are well preserved and can be divided into four types of filamentous microfossils. It suggests that the fossils may be derived from sulfur or iron oxidation chemolithotrophic prokaryotes and fungi. Based on the comparison studies of the microbial mineralization processes, two steps of biomineralization were hypothesized：（1） biology controlled mineralization; and （2） biology induced mineralization. At the early stage of the mineralization, the biology controlling mineralization is dominating; at the later stage, the biology inducing mineralization is the main mechanism. The composition of the fluids and the species of the microbes will determine the types of the minerals formed.

关键词： microfossils biomineralization black smoker Okinawa Trough