检索结果-南通市图书馆

Evidence from isotopic geochemistry as an indicator of eutrophication of Meiliang Bay in Lake Taihu, China

Science China Earth Sciences 2006年第z1期49卷 62-71页

作者： LIN Lin, WU Jinglu & WANG Sumin nanjing Institute of Geography & Limnology, Chinese Academy of Sciences, nanjing 210008, China Graduate University of the Chinese Academy of Sciences, Beijing 100039, China Chinese Acad Sci Nanjing Inst Geog & Limnol Nanjing 210008 Peoples R China Chinese Acad Sci Grad Univ Beijing 100039 Peoples R China

In this paper, Lake Taihu, a large shallow freshwater lake in China, is chosen as an example of reconstruction of eutrophication through the comparison between stable isotopes from dissolved nutrients and plants and water column nutrient parameters and integration of multiple proxies in a sediment core from Meiliang Bay including TN, TP, TOC, C/N, δ15N, δ13C, etc. Differences in aquatic plant species and trophic status between East Taihu Bay and Meiliang Bay are indicated by their variations in δ13C and δ15N of aquatic plants and δ15N of NH4+. A significant influence ofexternal nutrient inputs on Meiliang Bay is reflected in temporal changes in δ 15N of NH4+ and hydro-environmental parameters. The synchronous change between δ13C and δ15N values of sedimented organic matter (OM) has been attributed to elevated primary production at the beginning of eutrophication between 1950 and 1990, then recent inverse correlation between them has been caused by the uptake of 15N-enriched inorganic nitrogen by phytoplankton grown under eutrophication and subsequent OM decomposition and denitrification in surface sediments, indicating that the lake has suffered from progressive eutrophication since 1990. Based on the use of a combination of stable isotopes and elemental geochemistry, the eutrophication of Meiliang Bay in Lake Taihu could be better traced. These transitions of the lake eutrophication respectively occurring in the 1950s and 1990s have been suggested as a reflection of growing impacts of human activities, which is coincident with the instrumental data.

关键词： stable carbon isotope of OM, stable nitrogen isotope, eutrophication, Lake Taihu.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Hispanic Corridor formed as early as Hettangian: On the basis of bivalve fossils

引用

Chinese Science Bulletin 2002年第5期47卷 414-417页

作者： SHAJingengnanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, nanjing 210008, China (e-mail: jgsha @***) nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing China

After tracking the historical distribution of the pectinids being very capable of dispersion, it is easy to be found that the bivalves Chlamys (Chlamys) valoniensis (Defrance), Camptonectes (Camptonectes) auritus (von Schlo-theim) and Chlamys (Chlamys) textoria (von Schlotheim) first occurred in the Late Rhaetian, the end of the Triassic, or the earliest Hettangian, the earliest Jurassic of western Europe, and subsequently they spread into the southeastern coast of Palaeo-pacific through the Hispanic Corridor during the Hettangian or a little later. It has demonstrated that the Hispanic epicontinental seaway became established along the rifting area between North America and South America and Africa of the Pangaean supercontinent as early as Hettangian or even earlier, connecting western Tethys and eastern Palaeo-pacific and providing a corridor for migration and exchange of creatures between Tethys and Palaeo-pacific.

关键词： Hispanic Corridor form Hettangian.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

MAJOR PROBLEMS OF SUSTAINABLE DEVELOPMENT ALONG THE BANK AREA OF THE CHANGJIANG RIVER

引用

Chinese Geographical Science 2000年第2期10卷 97-104页

作者： YANG Gui-shan(nanjing Institute of Geography and Limnology,the Chinese Academy of Sciences, Nanjng 210008, P R. China) nanjing Institute of Geography and Limnology the Chinese Academy of Sciences Nanjing P. R. China

Developing the Changjiang(Yangtze) River and building a developed economic zone along the bank area of the Chanajiang River is a great strategic decision of the national macroeconomic development distribution. This decision has both given an impetus to fast development of the regional economy and exacerbated the contradiction among economy and resources and environment. In this paper, some major problems ekisting in economic sustainable development, such as scattered industrial structure, duplicated construction of the great projects, enlarging the development gap of the regional economy and deteriorated environment etc., have been studied. The results show that scattered structure and duplicated distribution of some key industries and projects, especially automobile, electronics and petrochemical industry and communication, power installations, is one of the reasons for low industrial economic benefit; the great development gap among upper, middle and lower reaches areas are enlarging since the 1990’ s; soil erosion, nood disaster and environmental pollution are still exacerliating due to unreasonable over-development. Based on the above analysis, this paper brings out some countermeasures and proposals for increasing the ability of regional sustainable development, including transregional reorganization of industrial structure linking by assets and speeding the process of regional economy integration; gradually controlling and reducing the development gap arnong upper, middle and lower reaches areas through regional cooperation on a mutually beneficial basis; as well as strengthening ecological construction and environmental protection and increasing environmental bearing capacity etc.

关键词： the bank area of the Changjiang River sustainable development structure problems environment deterioration

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Jianshangou Bed of the Yixian Formation in West Liaoning, China

引用

Science China Earth Sciences 2005年第3期48卷 298-312页

作者： CHEN Peiji1,2, WANG Qifei1, ZHANG Haichun1,2, CAO Meizhen1, LI Wenben1, WU Shunqing1 & SHEN Yanbin1 1. nanjing Institute of Geology and Palaeontolgoy, Chinese Academy of Sciences, nanjing 210008, China 2. State Key Laboratory of Palaeobiology and Stratigraphy, nanjing 210008, China 1. nanjing Institute of Geology and Palaeontolgoy Chinese Academy of Sciences 210008 Nanjing China 2. State Key Laboratory of Palaeobiology and Stratigraphy 210008 Nanjing China

The Jianshangou Bed is a set of fossil-bearing sedimentary interlayers of the basal volcano-sedimentary deposits of Yixian Formation in western Liaoning. It is rich in volcanic composition and consists of upper and lower grey-black shale, basal sandy conglomerate, top tuffaceous sandstone, middle massive silty mudstone and siltstone, as well as andesite, with a thickness of 28—95 m. The Jianshangou Bed is famous all over the world for its bearing early birds, angiosperms and feathered dinosaurs, and it also yields bivalves, gastropods, con- chostracans, ostracods, shrimps, insects, fish, amphibians, primitive mammals and other reptiles. These fossils are typical representatives of the Late Mesozoic Jehol Biota from eastern Asia. The Chaomidianzi and Sihetun formations, proposed in recent years, are regarded as the junior synonyms of the Jianshangou Bed. The Jehol Biota is endemic to eastern Asia, however, it has a large geographic distribution, more than half of the European territory. Many species of the biota have close relationships with the late Jurassic European counterparts, e.g. both Confuciusornis and Archaeopteryx are primitive birds, Sinosauropteryx has a similar skeleton construction with Compsognathus, the ostracode assemblage from the Jianshangou Bed is close to that from the Purbeck Bed in England, and Aeschnidium occurs in both the Jianshangou Bed and Solnhofen of Germany. Based on the biostratigraphic correlation, the Jianshangou Bed is more probably late Tithonian in age. The latest zircon U-Pb dating of the Jianshangou Bed gives 125.2 Ma, and is close to the feldspar Ar/Ar dating of 124.6 Ma. A glauconite dating of 125 Ma was once got from England near the J/K boundary within the Purbeck Bed, so it is still problematic to place the J/K boundary at 130, 135, 137, 142 or 145.5 Ma in the International Stratigraphic Charts.

关键词： Yixian Formation, Jianshangou Bed, Jehol Biota, J/K Boundary.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Molecular Gas and Dust in the Massive Star Forming Region S 233 IR

引用

Chinese Journal of Astronomy and Astrophysics 2004年第5期4卷 440-454页

作者： Rui-Qing Mao and Qin Zeng1 Purple Mountain Observatory, Chinese Academy of Sciences, nanjing 210008 2 National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 National Astronomical Observatories CAS NAOC Beijing 100012 China

The massive star forming region S 233 IR is observed in the molecular lines CO J = 2–1, 3–2, NH3 (1,1), (2,2) and the 870 um dust continuum. Four submillimeter continuum sources, labelled SMM 1–4, are revealed in the 870 um dust emission. The main core, SMM1, is found to be associated with a deeply embedded near infrared cluster in the northeast; while the weaker source SMM2 coincides with a more evolved cluster in the southwest. The best fit spectral energy distribution of SMM1 gives an emissivity of β = 1.6, and temperatures of 32 K and 92 K for the cold- and hot-dust components. An SMM1 core mass of 246 M☉, and a total mass of 445 M☉ are estimated from the 870 um dust continuum emission. SMM1 is found to have a temperature gradient decreasing from inside out, indicative of the presence of interior heating sources. The total outflow gas mass as traced by the CO J = 3–2 emission is estimated to be 35 M☉. Low velocity outflows are also found in the NH3 (1,1) emission. The non-thermal dominant NH3 line width as well as the substantial core mass suggest that the SMM1 core is a ``turbulent, massive dense core', in the process of forming a group or a cluster of stars. The much higher star formation efficiency found in the southwest cluster supports the suggestion that this cluster is more evolved than the northeast one. Large near infrared photometric variations found in the source PCS-IR93, a previously found highly polarized nebulosity, indicate an underlying star showing the FU Orionis type of behavior.

关键词： ISM: jets and outflows ISM: molecules ISM: dust, extinction stars:formation ISM: individual

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Spatial Chaos of Bose-Einstein Condensates in a Cigar-Shaped Trap

引用

Communications in Theoretical Physics 2007年第7期48卷 107-111页

作者： LI Fei REN Zhong-Zhou LUO Hai-Lu SHU Wei-Xing Department of Physics,nanjing University,nanjing 210008,ChinaWU Qin School of Basic Medical Science,Guangdong Medical College,Dongguan 523808,China Department of Physics Nanjing University School of Basic Medical Science Guangdong Medical College

The spatial chaos of Bose-Einstein condensates in a cigar-shaped trap is *** a system with asteady current,we construct the general solution of the 1st-order *** the boundedness condition of thegeneral solution, we obtain the Melnikov function predicting the onset of *** unpredictability of the system's dis-tribution of atom density is also theoretically *** a ^(23)Na system meeting the perturbation oondition,numericalsimulations show the existence of chaos,which is in accordance with our analytical *** simulations of a^(87)Rb system dissatisfying the perturbation condition also demonstrate that there exists chaos in the *** casewithout a current is also investigated.

关键词： Bose-Einstein condensates Melnikov function chaos

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Discovery of agglutinated foraminifers from the Longzhaogou Group in eastern Heilongjiang Province

引用

Science China Earth Sciences 2004年第2期47卷 122-127页

作者： LI Gang & YU Shanmao1. State Key Laboratory of Paleobiology Stratigraphy, nanjing Institute of Geology and Paleontology, Chinese Academy of Sciences, nanjing 210008, China 2.108th Coal-prospecting Team of Geological Bureau, NE China and Inner Mongolia Coal Company, Jixi 158100, China Correspondence should be addressed to Li Gang (email: gangli@***) 1. State Key Laboratory of Paleobiology Stratigraphy Nanjing Institute of Geology and Paleontology Chinese Academy of Sciences 210008 Nanjing China 2. 108th Coal-prospecting Team of Geological Bureau NE China and Inner Mongolia Coal Company 158100 Jixi China

The low diversity agglutinated foraminifers are recovered from the Qihulin Formation of the Longzhaogou Group in eastern Heilongjiang, China. The foraminiferal fauna consists of 9 species of 5 genera. The common members are Cribrostomoides nonioninoides (Reuss), Haplophragmoides concavus (Chapman), H. gigas minor Nauss. Although the diagnostic zonal taxa are absent in the agglutinated fauna, according to the global stratigraphic distribution of the above-mentioned species, and the associated Pseudohaploceras ammonite fauna, the foraminiferal fauna may be of a Barremian-Aptian (Early Cretaceous) age.

关键词： Early Cretaceous, agglutinated foraminifers, Longzhaogou Group, eastern Heilongjiang, China.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Construction of Optimal Truncated Low-Dimensional Dynamical systems directly from PDEs

引用

Communications in Nonlinear Science and Numerical Simulation 1998年第1期3卷 1-5页

作者： Hongliang ZHAO, Chuijie WU(LNM, Institute of Mechanics, cas, Beijing, 100080) (Air Force Institute of Meteorology, nanjing, 211101) Email: cjwu@*** LNM Institute of Mechanics CAS Beijing 100080 China Air Force Institute of Meteorology Nanjing 211101 China

ＩｎｔｒｏｄｕｃｔｉｏｎＷｈｅｎａｐｐｌｙｉｎｇｔｈｅｍｅｔｈｏｄｓｏｆｄｙｎａｍｉｃａｌｓｙｓｔｅｍｓｔｏｓｔｕｄｙｔｈｅｄｙｎａｍｉｃａｌｂｅｈａｖｉｏｒｏｆｓｏｍｅＰＤＥｓ，ｔｈｅｍｏｓｔｉｍｐｏｒｔａｎｔｓｔ... 详细信息

ＩｎｔｒｏｄｕｃｔｉｏｎＷｈｅｎａｐｐｌｙｉｎｇｔｈｅｍｅｔｈｏｄｓｏｆｄｙｎａｍｉｃａｌｓｙｓｔｅｍｓｔｏｓｔｕｄｙｔｈｅｄｙｎａｍｉｃａｌｂｅｈａｖｉｏｒｏｆｓｏｍｅＰＤＥｓ，ｔｈｅｍｏｓｔｉｍｐｏｒｔａｎｔｓｔｅｐｉｎｔｈｅｐｒｏｃｅｓｅｓｉｓ...

关键词： low dimensional dynamical system partial differential equations optimization

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

A NATION-WIDE SOIL SURVEY RATIONALIZES EXPLOITATION OF VARIOUS SOIL RESOURCES

引用

Bulletin of the Chinese Academy of Sciences 1996年第4期10卷 328-331页

作者： Xi Chengfan(nanjing Institute of Soil Sciences, cas, nanjing) cas Member

To tap the production potential of soil resources in China by making a nationwide soil investigation is a precondition for developing the farming production as a means of coping with the current population explosion and providing necessities for people’s *** article expounds practical methods for the survey and elucidates rational exploitation in line with soil conditions in different localities across the land.

关键词： soil A NATION-WIDE SOIL SURVEY RATIONALIZES EXPLOITATION OF VARIOUS SOIL RESOURCES line maps

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A high-resolution late Pleistocene record of pollen vegetation and climate change from Jingning, NW China

引用

Science China Earth Sciences 2006年第2期49卷 154-162页

作者： LI Chunhai12, TANG Lingyu1, FENG Zhaodong3,4, ZHANG Hucai2, WANG Weiguo3 & AN Chenbang3 1. nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, nanjing 210008, China 2. Nanjng Institute of Geography and Limnology, Chinese Academy of Sciences, nanjing 210008, China 3. Environment and Resources College, Lanzhou University, Lanzhou 730000, China 4. Beijing Normal University, Beijing 100875, China 1. nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing 210008 China 2. Nanjng Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210008 China 3. Environment and Resources College Lanzhou University Lanzhou 730000 China 4. Beijing Normal University Beijing 100875 China

With the support of 18 AMS-14C data, a high-resolution pollen record from the Suancigou section at Jingning, Gansu Province was established. Our results showed that the vegetation ex-perienced a series of changes characterized by the alternative growth and decline of forest and steppe components during the period from 44.2 to 11 ka B.P. in the Jingning area. Over the period of 44―29 ka B.P. (MIS3), coniferous forests were flourishing, indicating a humid climate with the tem-perature being lower than that of the present. Since 23 ka B.P., the vegetation was dominated by steppe-desert steppe under a cold and dry condition, and entered the Last Glacial Maximum domi-nated by desert steppe. Several periods of the marked decrease in the arborous pollen content in Suancigou well corresponded to the North Atlantic Heinrich events, especially to Heinrich event 3, further supporting that the Heinrich events were well reflected by the pollen record in the Loess Pla-teau as well.

关键词： Western Loess Plateau, pollen record, climatic change, late Pleistocene.

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：