检索结果-南通市图书馆

Science china Earth Sciences 2006年第6期49卷 622-631页

作者： TIAN Xiangjun1,2. XIE Zhenghui1, ZHANG Shenglei1 & LIANG Miaoling1 1. LASG, institute of Atmospheric Physics, chinese {2. of Sciences, beijing 10002., china 2. Graduate School of the chinese {2. of Sciences, beijing 100039, china 1. LASG Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China 2. Graduate School of the chinese academy of Sciences Beijing 100039 China

Subsurface runoff in a land surface model is usually parameterized as a single-valued function of total storage in a basin aquifer reservoir. This kind of parameterization is often sin-gle-valued function of storage-discharge under a steady or “quasi-steady” state, which cannot rep-resent the influence of aquifer recharge on subsurface runoff generation. In this paper, a new sub-surface runoff parameterization with water storage and recharge based on the Boussinesq-storage equation is developed. This model is validated by a subsurface flow separation algorithm for an ex-ample river basin, which shows that the new model can simulate the subsurface flow reasonably.

关键词： Zsubsurface runoff parameterization Boussinesq-storage equation waterstorage and recharge

Boundedness of solutions and existence of invariant tori for generalized pendulum type equation

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 1997年第20期42卷 1673-1675页

作者： HUANG Hai and YUAN Rong1. institute of Mathematics, chinese {2. of Sciences, beijing 100080, china 2. Department of Mathematics, beijing Normal University, beijing 100875, china institute of Mathematics Chinese Academy of Sciences Beijing China Department of Mathematics Beijing Normal University Beijing China

MOTIVATED by various significant applications to non-Newtonian fluid theory, diffusion offlows in porous media, nonlinear elasticity, and theory of capillary surfaces, several authors(see refs.[1,2. and references cited therein ) have recently studied the existence of periodicsolutions and other properties for the following differential equation:

关键词： boundeduess of solutions invariant tori quasiperlodic solutions Moser’s small twist theorem.

Digital image analysis of palaeoenvironmental records and applications

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 2002年第23期47卷 1957-1963,2025-2026页

作者： SUN Donghuai1,2. LIU Yu2.& TAN Ming31. South china Sea institute of Oceanology, {2. academy of Sciences. Guangzhou 510301, china 2. State Key Laboratory of Loess and Quaternary geology, Earth Environmental institute, {2. academy of Sciences, Xi’an 710075, china 3. institute of geology and Geophysics, {2. academy of Sciences, beijing 10002., china South china Sea institute of Oceanology Chinese Academy of Sciences Guangzhou China State Key Laboratory of Loess and Quaternary geology Earth Environmental Institute Chinese Academy of Sciences Xi’an China institute of geology and Geophysics Chinese Academy of Sciences Beijing China

Environmental change signals in geological or biological records are commonly reflected on their reflecting or transmitting images. These environmental signals can be extracted through digital image analysis. The analysis principle involves section line selection, color value reading and calculating environmental proxy index along the section lines, layer identification, auto-chronology and investigation of structure evolution of growth bands. On detailed illustrations of the image technique, this note provides image analyzing procedures of coral, tree-ring and stalagmite records. The environmental implications of the proxy index from image analysis are accordingly given through application demonstration of the image technique.

关键词： digital image environmental records.

Global convergence property of s-dependent GFR conjugate gradient method

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 1998年第23期43卷 1959-1965页

作者： WANG Changyu 1,2.and ZHANG Yuzhong\+1 1. institute of Operations Research in Qufu Normal University, Qufu 2.3165, china 2. institute of Applied Mathematics, chinese academy of Sciences, beijing 100080, china institute of Operations Research Qufu Normal University Qufu China institute of Applied Mathematics Chinese Academy of Sciences Beijing China

An \%S\%_dependent GFR method and a generalized conjugate gradient method are designed. Two estimated values of upper bounds for the ratio of β k to β FR k are given. The two convergence theorems are proved. The global convergent properties of \%s\%_dependent GFR method are obtained adopting several choice strategies of steplength and some results in recent literature are extended.

关键词： steplength linear search global convergence conjugate gradient.

Jinning granodiorite and diorite deeply concealed in the central Tarim Basin

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2005年第12期48卷 2061-2068页

作者： LI Yuejun1, 2. SONG Wenjie2. WU Genyao1, WANG Yifen1, LI Yuping2.& ZHENG Duoming2.1. institute of geology & Geophysics, {2. academy of Sciences, beijing 10002., china 2. Tarim Oil-field Company, Petrochina, Korla 841000, china 1. institute of geology & Geophysics Chinese Academy of Sciences 100029 Beijing China 2. Tarim Oil-field Company 841000 Korla PetroChina China

The 72.0-m-deep Well Tacan 1 in the central Tarim Basin is the deepest in china. Purplish gray medium-grained granodiorite containing dark gray fine-grained diorite xenolith is revealed at the base of the well (7169―72.0 m), and they are results of the Jinning magmatic activities. Trace-element geochemistry and REE profiles of both rock types are similar, indicating that they are calc-alkaline series I-type granitoid. Proxies of diorite signify the development of a magmatic arc due to subduction at ca. 12.0 Ma. The granodiorite was formed before 890―932.Ma. However, more study is needed to clarify if the arc diorite represents a ca. 300 Ma extension of the subduction or a reactivation during the orogenic collision event at ca. 900 Ma.

关键词： diorite, granodiorite, magmatic arc, Jinning orogeny, Tarim Basin.

Origin, Evolution and Mechanism of the Jehol Fauna

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 1991年第2期65卷 203-215页

作者： Wang Si’en institute of geology, {2. academy of geological Sciences, beijing Liu Linqun institute of geology Chinese Academy of Geological Sciences Beijing

This paper deals with the geographic distribution and geological setting of the Jehol (northeastHebei-southwest Liaoning-southeast Inner Mongolia) fauna, and discusses the origination and the evolution ofits major biological groups. It is demonstrated that the Yan-Liao (northern Hebei-western Liaoning) area is theprovenance for the fauna. Why the fauna originated and developed in the area was intimately related to suchfactors as the palaeoclimate, palaeogeography, crustal movement, volcanism and frequent reversals of magnet-ic polarity at that time, in addition to the internal factors of the organisms themselves.

关键词： Origin Evolution and Mechanism of the Jehol Fauna

Effects of the grain size distribution on the temperature-dependent magnetic susceptibility of magnetite nanoparticles

在线全文

学校读者我要写书评

暂无评论

Science china Earth Sciences 2010年第7期53卷 1071-1078页

作者： ZHAO XiangYu1,2.& LIU QingSong1 1 Paleomagnetism and Geochronology Laboratory (SKL-LE), institute of geology and Geophysics, {2. academy of Sciences, beijing 10002., china 2.Graduate University of {2. academy of Sciences, beijing 100049, china 1. Paleomagnetism and Geochronology Laboratory (SKL-LE) Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China2. Graduate University of Chinese Academy of Sciences Beijing 100049 China

Magnetite is an important magnetic remanence carrier in natural samples and therefore is of great interest in paleo-, rock-, and environmental magnetism. The magnetic properties of magnetite depend on many factors, e.g., concentration and grain size distribution (GSD). In this study, we theoretically investigated the temperature-dependent susceptibility (TDS) of magnetite nanoparticles with a lognormal GSD. Results show that the TDS is affected highly by the GSD mainly in three aspects. Firstly, the unblocking process becomes smoother with the increase of distribution width, characterizing as a wider Hopkinson peak on the TDS curve. Secondly, the blocking temperature increases with the increase of the median diameter or/and the distribution width. Thirdly, the maximum susceptibility decreases with the increase of distribution width, and has a logarithmic function relation with the standard deviation of the distribution. As a case study, this model was further applied to the thermal products of the chinese loess/paleosol samples to determine the granulometry of newly-formed magnetite upon heating based on TDS curves. The results demonstrate the fidelity and feasibility of this method to determine the GSD of nano-sized magnetic particles.

关键词： Néel theory temperature dependence of susceptibility grain size distribution

Two-dimensional Riemann problems of simplified Euler equation

在线全文

学校读者我要写书评

暂无评论

chinese Science Bulletin 1998年第6期43卷 441-444页

作者： YANG Xiaozhou 1,2.and HUANG Feimin+1 1. institute of Applied Mathematics, chinese {2. of Sciences, beijing 100080, china 2. Department of Mathematics, Shantou University, Guangdong 515063, china institute of Applied Mathematics Chinese Academy of Sciences Beijing China Department of Mathematics Shantou University Guangdong China

The two-dimensional Riemann problem of simplifed Euler equation is discussed, in which initial value contains two different constant states that are separated by a smooth curve. This problem is a natural description of realistic phenomena, but it is hard to study by conventional idea. So a new approach is proposed. Some new properties about two-dimensional rarefaction wave, shock wave and intermediate state of solutions are disclosed.

关键词： D Riemann problem implicit functions cylindrical surface pencil of cylindrical surface.

Isotopic compositions of small shelly fossil Anabarites from Lower Cambrian in Yangtze Platform of South china: Implications for palaeocean temperature

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10期17卷 1185-1191页

作者： Chen Yongquan1,2. Jiang Shaoyong1, Ling Hongfei1, Yang Jinghong1 and Wan Defan3(1. State Key Laboatory for Mineral Deposits Research and Center for Marine Geochemistry Research, Department of Earth Sciences, Nanjing University, Nanjing 2.0093, china 2. Tarim Oilfield Company Exploration & Development Research institute, Ku’erle 841000, china 3. institute of Mineral Resources, chinese academy of geological Sciences, beijing 100037, china) State Key Laboatory for Mineral Deposits Research and Center for Marine Geochemistry Research Department of Earth Sciences Nanjing University Nanjing 210093 China arim Oilfield Company Exploration & Development Research institute Ku’erle 841000 China institute of Mineral Resources Chinese Academy of Geological Sciences Beijing 100037 China

Anabarites belong to small shelly fossils (SSF), which occur widely in the Lower Cambrian strata of Yangtze Platform in South china. They are phosphate shell in composition and represent the earliest stage of the Cambrian bioradiation of Bilateria, the so-called "Cambrian Explosion". In this study, we attempted to separate Anabarites fossils from Lower Cambrian dolostones, and we obtained samples of both the fossils (SSF) and the granular phosphates (GP). Isotopic analyses were performed on samples of SSF, GP, and matrix dolostone (DH-2.). The results showed that the δ30Si values of the quartz filling in fossils celoms, and the siliceous materials in granular phosphates are -0.6‰ and -0.7‰, which is different from normal sedimentary siliceous rocks from the Lower Cambrian strata (0—0.7‰) as reported by Li et al., but is consistent with the data for siliceous rocks and cherts of submarine hydrothermal origin. It is likely that a later hydrothermal replacement could have taken place in the SSF-bearing sedimentary rocks. The oxygen isotope values of the phosphate of SSF and GP are 16.8‰ and 17.0‰, respectively. These are significantly higher than the Neoproterozoic phosphate ores (10.9‰—13.9‰) as reported by Ling et al., hence, late diagenesis and hydrothermal replacement may not have caused a significant change in the oxygen isotope compositions of the small shelly fossils, and the calculated temperatures (2..4—2..3℃) for palaeo-seawater using a SSF phosphate oxygen isotope thermometer are therefore considered here as the upper limit of seawater temperature in the Early Cambrian ocean of the Yangtze Platform.

关键词： Anabarites oxygen isotope silicon isotope paleo-temperature.

Debris Flow Hazard Assessment Based on Support Vector Machine

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Wuhan University Journal of Natural Sciences 2006年第4期11卷 897-900页

作者： YUAN Lifeng 1, 2., ZHANG Youshui 3 1. institute of Mountain Hazards and Environment, chinese {2. of Sciences, Chengdu 610041, Sichuan, china 2. Graduate University of chinese {2. of Sciences, beijing 100049, china 3. institute of Geographical Sciences and Natural Resources Research, chinese {2. of Sciences, beijing 100101, china institute of Mountain Hazards Environment Chinese Academy of Sciences 610041 Chengdu Sichuan China Graduate University of chinese academy of Sciences 100049 Beijing China institute of Geographical Sciences Natural Resources Research Chinese Academy of Sciences 100101 Beijing China

Seven factors, including the maximum volume of once flow , occurrence frequency of debris flow , watershed area , main channel length , watershed relative height difference , valley incision density and the length ratio of sediment supplement are chosen as evaluation factors of debris flow hazard degree. Using support vector machine （SVM） theory, we selected 2.9 basic data of 37 debris flow channels in Yunnan Province as learning samples in this study. We create a debris flow hazard assessment model based on SVM. The model was validated though instance applications and showed encouraging results.

关键词： debris flow hazard assessment support vector machine (SVM)