检索结果-南通市图书馆

Chinese Geographical Science 2002年第1期12卷 44-49页

作者： ZHANG Jian chun, PENG Pu zhuo(department of urban and {2. sciences,nanjing university,nanjing 2.0093,P.R.china ) department of urban and {2. sciences Nanjing University Nanjing P. R. China

Rainfall resource is very important to the development of society and economy,especially to eastern Jianghuai watershed which is now facing serious challenge of water shortage. Based on the observational records covering the period from 1957 to 1999,the characteristics of precipitation changing over eastern JiangHuai watershed and its connection to sediment discharge in Chihe River valley were studied using tendency analysis and correlation analysis .Results show that the rainfall in this area had a declining tendency in Spring at a rate of -2..2.m/10a, annual and Summer precipitation was increasing at the rate of 10.6mm/10a and 14.8mm/10a. The gray correlation analysis shows that sediment discharge correlates most closely with runoffs and the frequency of the rainstorm with a daily precipitation of 50-100mm, on the second place,with the rainfall and the frequency of the rainstorm of a daily precipitation no less than 100mm;and thirdly with the number of rainy days. In addition, the paper suggests the major countermeasures and methods for controlling of soil and water losses in this area.

关键词： eastern Jianghuai watershed Chihe River rainfall sediment discharge correlation grade

CHALLENGES AND PROBLEMS: china'S urban GOVERNANCE

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 2002年第2期12卷 152-156页

作者： WANG Hong, GU Chao lin(department of urban and {2. sciences, nanjing university, nanjing 2.0093, P.R.china) department of urban and {2. sciences Nanjing University Nanjing 210093 P. R. China

china′s urban reforms have brought social progress and development, but a comprehensive national system of social welfare (for example, unemployment insurance, pensions, medical care and public housing) for new migrants from rural areas is lacking. One of the most remarkable changes in Chinese cities in the last decade was a change in social "equality", with the rise of new poverty both in individual communities and some social groups in urban society. However, there is little social assistance and public infrastructure for the migrants. Governments or communities or individual should pay attention to the control of new urban poverty and new slums. This paper consider that it is necessary to launch a successful policy, which include mainly: 1) accommodating urban growth through low cost investment projects; 2. urban economy depends heavily on successful macroeconomic policy; 3) to broaden the three channels linking adjustment to the incidence of urban poverty; 4) to restructure urban economic based on the high or new technology; 5) to coordinate relationship between urban economic growth and environment management for sustainable development of Beijing′s metropolitan fringe.

关键词： urban challenges and problems urban governance urban policies

Thermal-rheological structure of the lithosphere beneath Jiyang Depression:Its implications for geodynamics

在线全文

学校读者我要写书评

暂无评论

Science china Earth sciences 2005年第10期48卷 1569-1584页

作者： LIU Shaowen1,2. WANG Liangshu2. GONG Yuling2. LI Cheng2. LI Hua2.& HAN Yongbing2.1. department of urban and {2., nanjing university, nanjing 2.0093, china 2. department of Earth sciences, nanjing university, nanjing 2.0093, china department of urban and {2. nanjing university nanjing china department of Earth sciences{2. nanjing china

Jiyang Depression, located in the southeast Bohai Bay Basin, has the geomorpho-logic framework of multiple uplifts intervening with sags. Combined the abundant geo-temperature data and thermo-physical parameters of rock samples derived from oil and gas exploration during the past years, with geothermal approaches, here we investigate the litho-spheric thermal regime of this depression. Consequently, based on the obtained thermal struc-ture of the lithosphere, along with rheological modeling, the lithospheric rheological profiles of Jiyang Depression are then determined. Our results show that the temperature at the bottom of sedimentary cover within depression varies from 12.℃ to 2.8 ℃ , accompanied with the base-ment heat flow ranging between 54.3 and 60.5 mW/m2. and 406℃-436℃ for temperature at the bottom of the upper crust, along with heat flow varying from 47.7 to 52.6 mW/m2. while the tem-perature at the bottom of the middle crust is between 537 ℃ and 572.℃, as well as heat flow ranging from 41.3 to 56.3 mW/m2. The temperature at Moho ranges from 669 ℃ to 72. ℃, the heat flow derived from mantle is between 38.1 and 43.1 mW/m2. and calculated thickness of the thermal lithosphere beneath depression varies from 71 to 90 km. Lithospheric thermal regime is a close correlation with such factors as crustal thickness and surface heat flow, etc. Usually, the larger the surface heat flow, the larger the deep temperature and heat flow within lithosphere, and the thinner the thermal lithospheric thickness. This high thermal regime of the lithosphere in Jiyang Depression is thought to be related to Cenozoic back-arc spreading during the western Pacific plate subduction into Eurasian continent. Lithospheric rheological modeling shows that the lithosphere in Jiyang Depression is characterized by its distinct rheological stratification as follows: The upper and most part of the middle crust are of brittle, while the lower crust and the lower part of middle crust are all ductile

关键词： Jiyang Depression, geothermics, rheology, effective elastic thickness, geodynamics.

Origin of the Red Earth sequence on the northeastern Tibetan Plateau and its implications for regional aridity since the middle Miocene

在线全文

学校读者我要写书评

暂无评论

Science china Earth sciences 2006年第5期49卷 505-517页

作者： WANG Xianyan1,7, LU Huayu1,2. JI Junfeg3, WANG Xiaoyong1,7, ZHAO Jingbo4, HUANG Baochun5 & LI Zhen6 1. SKLLQG, Institute of Earth Environment, Chinese Academy of sciences, Xi’an 710075, china {2., nanjing university, nanjing 2.0093, china 3. department of Earth sciences, nanjing university, nanjing 2.0093, china 4. department of Geography, Shaanxi Normal {12., Xi’an 710062. china 5. Institute of Geology and Geophysics, Chinese Academy of sciences, Beijing 10002., china 6 department of Geography, Qinghai Normal {12., Xining 810008, china 7. Graduate School of the Chinese Academy of sciences, Beijing 100039, china 1. SKLLQG Institute of Earth Environment Chinese Academy of Sciences Xi’an 710075 China 7. Graduate School of the Chinese Academy of sciences Beijing 100039 China 2. department of urban and resources sciences Nanjing University Nanjing 210093 China 3. department of Earth sciences Nanjing University Nanjing 210093 China 4. department of Geography Shaanxi Normal University Xi’an 710062 China 5. Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China 6. department of Geography Qinghai Normal University Xining 810008 China

The Red Earth deposit around Xining, northeastern Tibetan Plateau, has beenstudied in terms of soil micro-structure, grain-size distribution, major- and trace-elementchemistry and magne-tostratigraphy. Field investigations indicate that the Red Earth sequenceconsists of 2. visually definable yellow-brown and weakly-developed soils interbedded with reddishstrongly-developed soils, and has a similar structure to the aeolian Red Clay deposit on the ChineseLoess Plateau. Grain-size analysis shows that the Red Earth deposit is very fine-grained with anegligible sand fraction ( > 63 μm). Thin-section observations under light microscopy show that thedeposit has a clayey texture and the coarse fraction ( > 10 μm) mainly consists of quartz,feldspar and micas. Pyroxene and hornblende were also observed. This mineralogical composition ofthe coarse fraction is similar to that of the Quaternary loess. In addition, all of the mineralgrains are semi angular semi-angular and are generally finer than 63 μm. There is a good agreementbetween the major and minor trace element chemistry of loess-soil units and the Red Earth *** REE distributions of the loess-soil and the Red Earth deposit are similar in shape, withenriched LREE and fairly flat HREE profiles and a clear negative Eu anomaly. The geochemicalcharacteristics of the Red Earth deposit are also identical to those of upper continental crust,thus indicating a wind-blown origin. Magnetostratigraphic investigation shows that onset of the RedEarth deposition predates 11.4 Ma BP (13.6 Ma at a nearby site). The distribution of the reportedMiocene aeolian loess at Qin''an of the Loess Plateau is still unknown. Our results indicate thatthis aeolian deposit had extended to the northeastern Tibetan Plateau by at least the middleMiocene. The similarity of the element geochemistry between the Red Earth deposit and the overlyingloess shows that they may have similar sources and dynamic transport system, and may indicate thatthe

关键词： Red Earth deposit, Northeastern Tibetan Plateau, aeolian deposit, aridity of Asia, the middle Miocene.

Study on lithogeochemistry of Middle Jurassic basalts from southern china represented by the Fankeng basalts from Yongding of Fujian Province

在线全文

学校读者我要写书评

暂无评论

Science china Earth sciences 2006年第10期49卷 1020-1031页

作者： ZHOU Jincheng1,2. JIANG Shaoyong1,2. WANG Xiaolei1,2. YANG Jinghong 1,2.& ZHANG Mengqun 3 1. State Key Laboratory of Mineral Deposit Research, nanjing university, nanjing 2.0093,{2. 2. department of Earth sciences, nanjing university, nanjing 2.0093,{2. 3. Modern Analysis Center, nanjing university, nanjing 2.0093,{2. 1. State Key Laboratory of Mineral Deposit Research Nanjing University Nanjing 210093 China 2. department of Earth sciences Nanjing University Nanjing 210093 China 3. Modern Analysis Center Nanjing University Nanjing 210093 China

There exists an E-W trending Middle Jurassic volcanic zone in southern china. The Fankeng basalts in the Yongding basin of Fujian Province are considered to be a typical example. The Fankeng basalts have TiO2.contents in the range of 1.92.-3.2.%. They are classified as high-Ti basalts. They also have higher total Fe (averaging FeO* = 11.09%). The Middle Jurassic Fankeng basalts from southwestern Fujian have obvious distinctive lithogeochemical features from early Cre- taceous basalts from southeastern coast of china. They have higher HFSE, such as Th, Nb, Ta, Zr and Ti. Their element ratios related with HFSE, such as Zr/Ba, La/Nb, La/Ta ,Zr/Y, Ti/Y, Ba/Nb, K/Ti and Rb/Zr are similar to those of OIB. The most samples have ε Nd(T) of-0.70-0.2., which are near chondrite. Some samples have higher ε Nd(T) of ***, these basaltic magmas might be derived from depleted asthenospheric mantle. The lithogeochemical characteristics of the Fankeng basalts may be caused by interaction between asthenosphere and lithosphere at the time. The (Early-) Middle Jurassic basalts and gabbros from southeastern Hunan, southern Jiangxi and northern Guangdong provinces show similar geochemical features to those of the Fankeng basalts from the Yongding of Fujian. Occurrence of these OIB-type basalts in the area may be regarded as the petrological mark of upwelling of asthenosphere at the time. Upwelling of asthenosphere has led to tectonic extension and the formation of rifted basin in the area.

关键词： interaction between asthenosphere and lithosphere, lithogeochemistry, basalts, Middle Jurassic, southern china.

L-R smash products for bimodule algebras

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6期16卷 580-587页

作者： ZHANG Liangyun (department of Mathematics, nanjing Agricultural {2., nanjing 2.0095, china department of Mathematics, nanjing university, nanjing 2.0008, china) [a] department of Mathematics Nanjing Agricultural University Nanjing China [b] department of Mathematics Nanjing University Nanjing China

In this paper, we prove that the L-R smash product A(?)H is exactly the twisted smash product A * H if H is a finite dimensional cocommutative Hopf algebra, and give a sufficient and necessary condition for L-R smash products to be bialgebras (Hopf algebras) . For any finite dimensional coquasitriangular Hopf algebra (H,σ), we prove that the L-R smash product H(?)H is semisimple Artinian if H is semisimple and H * is unimodular. In particular, the L-R smash product D(H)* (?)D(H)* semisimple Artinian if the Drin-fel'd double D(H) is semisimple.

关键词： bimodule algebras L-R smash products coquasitriangular Hopf algebras Long bialgebras.

EPR studies of Mn^(2.) in the Loess Plateau of central china: Implication for variation of the East Asia summer monsoon

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 1998年第1期43卷 72-75页

作者： CHEN Jun\+1, JI Junfeng\+1, SU Yuanxia\+2.and LU Huayu\+31. department of Earth sciences,{2., nanjing 2.0093, china 2. Center of Material Analysis,{2., nanjing 2.0093, china 3. Xi’an Laboratory of Loess and Qu department of Earth sciences Nanjing University Nanjing China Center of Material Analysis Nanjing University Nanjing China Xi’an Laboratory of Loess and Quaternary Geology Chinese Academy of Sciences Xi’an China

Mn 2. EPR intensity recorded in the Chinese loess_paleosol sequence shows close correlation with magnetic susceptibility and Sr content as well as the oscillation of paleoclimate. Thus Mn 2. EPR signal can serve as an... 详细信息

关键词： paleomonsoon loess paleosol EPR signal of Mn 2.

Discovery of Corallina fossil from the Middle Cambrian of Taijiang County, Guizhou Province, china

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2000年第6期45卷 544-547页

作者： YANG Ruidong & ZHAO Yuanlong department of Earth sciences,{2., nanjing 2.0093, china department of resources, Guizhou university of Technoiogy, Guiyang 550002. china department of Earth sciences Nanjing University Nanjing China department of resources Guizhou University of Technology Guiyang China

Abundant and well-preserved macroalgae fossils have been discovered in silty mudstones and shales from the Middle Cambrian of Taijiang County, Guizhou Province, china. Corallina Paraamphiroa siniansis gen. et sp. nov. in the Kaili Fm., is the earliest Corallina fossil, which usually coexists with other carbonaceous macroalgae fossils on the bedding planes of mudstone and shale and is different from the calcareous and phosphatized Precambrian-Cambrian thallus discovered in the Lower Cambrian of Siberia and the Doushantou phosphate rocks of Weng’an County, Guizhou Province, china. The discovery of calcified thallus in the Kaili Fm. bears great importance on the study of phylogeny and evolution of early calcareous macroalgae.

关键词： Corallina Middle Cambrian Guizhou Province china.

One-step estimation for varying coefficient models

在线全文

学校读者我要写书评

暂无评论

Science china Mathematics 2005年第2期48卷 198-213页

作者： TANG Qingguo & WANG Jinde department of Mathematics, nanjing university,{2., china Institute of sciences, PLA university of Science and Technology, nanjing 2.0007, china 1. department of Mathematics Nanjing University 210093 Nanjing China 2. Institute of sciences PLA University of Science and Technology 210007 Nanjing China

A one-step method is proposed to estimate the unknown functions in the varying coefficient models, in which the unknown functions admit different degrees of smoothness. In this method polynomials of different orders are used to approximate unknown functions with different degrees of smoothness. As only one minimization operation is employed, the required computation burden is much less than that required by the existing two-step estimation method. It is shown that the one-step estimators also achieve the optimal convergence rate. Moreover this property is obtained under conditions milder than that imposed in the two-step estimation method. More importantly, as only one minimization operation is employed, the full asymptotic properties, not only the asymptotic bias and variance, but also the asymptotic distributions of the estimators can be derived. The asymptotic distribution results will play a key role for making statistical inference.

关键词： varying coefficient model, one-step estimation, asymptotic distribution, optimal convergence rate.

STUDY ON THE FREQUENCY AND PRINCIPLE OF FLOOD CATASTROPHE IN THE CHANGJIANG DELTA AND ITS NEIGHBORING REGIONS IN THE LAST 2.00 YEARS

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 2001年第2期11卷 137-143页

作者： ZHANG Sheng，ZHU Cheng，ZHANG Qiang (department of urban and {2. sciences, nanjing university, nanjing 2.0093,P. R. china) department of urban and {2. sciences Nanjing University Nanjing P. R. China

Documented materials, especially those about flooding catastrophe, are abundant comprehensive and well-preserved, which makes possible the systematical collection of materials about historical document about climate evolution in Changjiang (Yangtze) Delta region and its neighboring areas. We make good use of the exceptional information to discuss the genesis and principle of flooding in this region. Analysis shows that the main flooding periods in the studied region in the last 2.00 years were the Western Jin Dynasty, Eastern Jin Dynasty, Northern and Southern Dynasties, Southern Song Dynasty, Yuan Dynasty, Ming Dynasty and Qing Dynasty. The periods with flooding peak values were the 4th century, 5th century, 7th century, 9th century, early 12.h century, early 14th century, mid-15th century, and early 18th century A.D. Possibility of reappearance of flooding peak value in the early 2.st century will be great, and the hazard prevention and the hazard reduction will be still hard.

关键词： Changjiang Delta historical flood frequently-occurred flood period flooding peak period