检索结果-南通市图书馆

Aridity/humidity status of land surface in China during the last three decades

Science China earth sciences 2005年第9期48卷 1510-1518页

作者： WU Shaohong1, YIN Yunhe1,2. ZHENG Du1 & YANG Qinye1 1. Institute of Geographical sciences and Natural resources Research, Chinese Academy of sciences (CAS), beijing 100101, China 2. Graduate school of the CAS, beijing 100039, China 1. Institute of Geographical sciences and Natural resources Research Chinese Academy of Sciences (CAS) 100101 Beijing China 2. Graduate school of the CAS 100039 Beijing China

To clarify aridity/humidity status of land surface is helpful for studying environmental background and regional differences, seeking causes of environmental change, and providing a scientific basis for researches on climate change in the future. In this paper, the authors calcu- lated potential evapotranspiration of China using data from 616 meteorological stations during the period of 1971―2.00 with the Penman-Monteith model recommanded by FAO in 1998. Vy- sothkii’s model was used to calculate aridity/humidity index. Then the calculated results of sta- tions were interpolated to land surface using ArcGIS. Results show that the annual average po- tential evapotranspiration is 400―1500 mm in the whole country, 600―800 mm in most parts of it; and 350―1400 mm in growing season (April―Octobor), which is nearly 2.0 mm less than the annual average. According to the aridity/humidity indexes of 1.0, 1.5 and 4.0, the aridity/humidity status is categorized to four types, namely, humid, subhumid, semiarid and arid. A majority of stations (76%) are more humid in growing season than the annual average. Results of com- prisons between the distribution map of aridity/humidity index with that of precipitation and vegetation indicate a good consistence of aridity/humidity status with natural environment. Therefore potential evapotranspiration calculated with modified FAO’s Penman-Monteith model in combination with aridity/humidity index that considers water balance can more reasonably explain the actual land surface aridity/humidity status of China.

关键词： potential evapotranspiration, aridity/humidity status, land surface, regional differences, Penman-Monteith.

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

Effects of salinity on methane gas hydrate system

引用

Science China earth sciences 2007年第11期50卷 1733-1745页

作者： YANG DingHui1 & XU WenYue2.1 Department of Mathematical sciences, Tsinghua university,{2. 100084, China 2.school of earth & Atmospheric sciences, Georgia Institute of Technology, Atlanta, GA 30332. USA 1. Department of Mathematical sciences Tsinghua University Beijing 100084 China 2. school of earth & Atmospheric{2. Georgia Institute of Technology Atlanta GA 30332 USA

Using an approximately analytical formation, we extend the steady state model of the pure methane hydrate system to include the salinity based on the dynamic model of the methane hydrate system. The top and bottom boundaries of the methane hydrate stability zone (MHSZ) and the actual methane hy-drate zone (MHZ), and the top of free gas occurrence are determined by using numerical methods and the new steady state model developed in this paper. Numerical results show that the MHZ thickness becomes thinner with increasing the salinity, and the stability is lowered and the base of the MHSZ is shifted toward the seafloor in the presence of salts. As a result, the thickness of actual hydrate occur-rence becomes thinner compared with that of the pure water case. On the other hand, since lower solubility reduces the amount of gas needed to form methane hydrate, the existence of salts in sea-water can actually promote methane gas hydrate formation in the hydrate stability zone. Numerical modeling also demonstrates that for the salt-water case the presence of methane within the field of methane hydrate stability is not sufficient to ensure the occurrence of gas hydrate, which can only form when the methane concentration dissolved in solution with salts exceeds the local methane solubility in salt water and if the methane flux exceeds a critical value corresponding to the rate of diffusive methane transport. In order to maintain gas hydrate or to form methane gas hydrate in marine sedi-ments, a persistent supplied methane probably from biogenic or thermogenic processes, is required to overcome losses due to diffusion and advection.

关键词： methane gas hydrate,solubility,stability of hydrate,salinity,phase equilibrium

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

Re-Os(ICP-MS)dating of the massive sulfide ores from the Jinchuan Ni-Cu-PGE deposit

引用

Science China earth sciences 2005年第10期48卷 1672-1677页

作者： YANG Gang1,2. DU Andao1, LU Jiren3, QU Wenjun1 & CHEN Jiangfeng2.1. National Research Center of Geoanalysis, beijing 100037, China 2. Laboratory for earth Material Cycling,{2. of earth and Space sciences, university of Science and Technology of China, Hefei 2.002., China 3. Institute of Mineral Resource, Chinese Academy of Geological sciences, beijing 100037, China National Research Center of Geoanalysis beijing China Laboratory for earth Material Cycling School of Earth and Space Sciences University of Science and Technology of China Hefei China Institute of Mineral Resource Chinese Academy of Geological sciences beijing China

Massive sulfide ore from the Jinchuan Ni-Cu-PGE deposit was dated by Re-Os technique using Carius Tube digestion, Os distillation, Re extraction by acetone and ICP-MS measurement. An isochron giving an age of 833 ± 35 Ma, initial 187Os/188Os ratio of 0.2.9 ± 0.018 (MSWD = 1.7) and γOs = 130 ± 15 is obtained. The Re-Os age obtained agrees, within analytical uncertainties, with previous SHRIMP zircon U-Pb age of 82. ± 8 Ma (n=5, MSWD = 4.3). The result suggests that the deposit was formed at Neoproterozoic and that the formation of the Jinchuan Ni-Cu-PGE sulfide deposit may be closely related to the plume activity, which were attributed to the breakup of the Rodinia supercontinent. The high γOs of the massive ores sug-gests that crustal material was involved in the formation of the Jinchuan deposit, however, the quantity of the added crustal material is less than 10%.

关键词： Jinchuan Ni-Cu-PGE deposit, Re-Os dating, ICP-MS.

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

N_2. emissions from agricultural soils in the North China Plain: the effect of chemical nitrogen fertilizer and organic manure

引用

Journal of Environmental sciences 2000年第4期12卷 463-468页

作者： DONG Yun\|she 1,2.3 , Dieter Scharffe 2. Manfred Domroes 3, QI Yu chun 1, ZHANG Shen 1 (1. Institute of Geographic sciences and Natural resources Research, Chinese Academy of sciences, beijing 100101, China E\|mail: dongys@*** 2. M 中科院地理科学与资源所北京 1 0 0 1 0 Max- Planck-Institute of Chemistry 德国 Mainz 550 2 0 Mainz university 德国 Mainz 550 99

An enclosed chamber technique was used to measure N 2. emissions from intensively agricultural soils of the North China Plain during the periods of 1995—1996 and 1997—1998, to reflect distinct components of winter wheat and summer maize growing seasons. The results showed that the continuous application of fertilizer in agricultural soils increased N\-2. emissions by a factor of 2..1—2..1, the calculated annual chemical N fertilizer\|transformed N\-2.\|N emissions was 0.67%. Our results indicated that the application of organic manure also had a significant influence on soil N 2. emissions, which combined with the use of chemical N increased about 2.% in a year. It was calculated that there were about 0.11% N of organic manure transformed as N 2. N. Annual mean N 2. emission from our study area of fertilized soils was estimated to be 57.1 μgN 2./(m 2.h). A weak correlation was also found between N 2. emissions and soil available nitrogen content NH + 4.

关键词： N_2. emissions the North China Plain agricultural soils chemical nitrogen organic manure

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

The developmental trend of labrum and median eyes of Orsten-type preserved Phosphatocopina (Crustacea)

引用

Science China earth sciences 2010年第1期53卷 18-26页

作者： LIU Zheng 1,2.& DONG XiPing 1,2.1 school of earth and Space{2.,Peking university,beijing 100871,China 2.State Key Laboratory of Palaeobiology and Stratigraphy,Nanjing Institute of Geology and Palaeontology,Chinese Academy of{2.,Nanjing 2.0008,China 1. school of earth and Space{2. Peking University Beijing 100871 China2. State Key Laboratory of Palaeobiology and Stratigraphy Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences Nanjing 210008 China

The Phosphatocopina (Crustacea,Arthropoda) is an important group of 'Orsten-type' preserved *** is resolved as the sister-group of *** we study the labrum,the median eyes,and the inner lamella of Phosphatocopina based on the selected specimens respectively from western Hunan,South China,and *** labrum characters of different species exhibit interspecific *** ratio of labrum length/shield length is significant to the reconstruction of the ontogeny of *** labrum characters should be introduced to the diagnosis of *** the earliest growth stage,the median eyes were inconspicuous,almost as flat as the other area of the ***,with the growth of the individuals they became *** were two obviously concave structures on the ventral side of the hypostome in later stages,which were the positions where the median eyes should have been *** addition,the two modes of preservation of the inner lamella,i.e.,that of shrinking and that of bulging up,are interpreted as the preservational artifact herein.

关键词： Phosphatocopina Crustacea Orsten-type preservation morphology ontogeny Cambrian South China Sweden

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

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

引用

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 resources, Nanjing university, Nanjing 2.0093, China 2. Department of{2. sciences, Nanjing university, Nanjing 2.0093, China Department of Urban and resources Nanjing university Nanjing China Department of earth sciences Nanjing{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.

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 seismites in Upper Sinian stratiform lead-zinc deposits in Dadu River valley, Sichuan, China: Implication for ore genesis

引用

Science China earth sciences 2006年第11期49卷 1135-1146页

作者： LIN Fangcheng1,2.& PAN Guitang2.1. Geoscience College, Chengdu university of Technology, Chengdu 610059, China 2. Chengdu Institute of Geology and Mineral resources, Chengdu 610082. China 1. Geoscience College Chengdu University of Technology Chengdu 610059 China 2. Chengdu Institute of Geology and Mineral resources Chengdu 610082 China

A number of lead-zinc sulphide deposits have been discovered in recent years in dolo- mitic rocks of the Upper Sinian Dengying Formation in the Dadu River valley region, Sichuan Province, China. The lead-zinc mineralization is closely associated with a black siliceous exhalite that has been traced over 50 km of strike. This makes Dadu River valley the most extensive stratiform non-ferrous sulphide horizon having been discovered to date in China. In a previous study by the first author (LIN), these deposits were recognised as belonging to the broad spectrum of lead-zinc sedimentary exhala- tive (SEDEX) deposits. In this paper, seismites and seismogenetic structures occurring in close association with the Dadu River valley mineralized zone are described. The close spatial and temporal relationship between the seismites and mineralization provides strong evidence for the hypothesis that the lead-zinc SEDEX deposits formed in direct response to earthquake activities around the Sinian-Cambrian boundary. The earthquakes are postulated to be an effective dynamic mechanism for triggering the upward migration of deep circulating ore fluids along synsedimentary growth faults and their exhalation onto the sea-floor to form the extensive deposits of stratiform lead-zinc sulphide ore.

关键词： seismites, earthquake, lead-zinc deposit, hydrothermal exhalation, Upper Sinian Dengying Age.

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

Human remains and the environment of Early Pleistocene in the Nihewan Basin

引用

Science China earth sciences 2004年第5期47卷 437-444页

作者： CAI Baoquan1 & LI Qiang2.1. Department of History, Xiamen university, Fujian 361005, China 2. Institute of Vertebrate Palaeontology and Palaeoanthropology, Chinese Academy of sciences,{2. 100044, China Xiamen Univ Dept Hist Fujian 361005 Peoples R China Chinese Acad Sci Inst Vertebrate Paleontol & Paleoanthropol Beijing 100044 Peoples R China

A new Early Pleistocene Paleolithic site was found in July 2.01 in the Nihewan Ba-sin, Hebei Province. Totally 500 mammal specimens assigned to 2. species and 5 lithic artifacts were collected. The coexistence of Allophaiomys deucalion, Borsodia chinensis and Yangia tingi provides important evidence of chronology. On the basis of the comparison of mammalian fauna, the date of Paleolithic artifacts is probably earlier than 1.8 MaBP, possibly 2.0 MaBP. This is the earliest evidence of hominid activity found so far in North China. The hominid at that time in the Nihewan Basin lived in an environment of arid grasslands with scattered trees of temperate zone. This discovery is significant to the study of human origin and cultural development.

关键词： human remains, environment, Early Pleistocene, Nihewan.

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

The control of syndepositional faulting on the Eogene sedimentary basin fills of the Dongying and Zhanhua sags, Bohai Bay Basin

引用

Science China earth sciences 2004年第9期47卷 769-782页

作者： LIN Changsong1, ZHENG Herong2. REN Jianye1, LIU Jingyan1 & Qiu Yigang1 1. Department of Energy Geology, China university of geosciences,{2., China 2. Petroleum Exploration and Production Institute, Sino-Petroleum and Chemistry Cooperation,{2., China China Univ Geosci Dept Energy Geol Beijing 100083 Peoples R China Sino Petr & Chem Cooperat Petr Explorat & Prod Inst Beijing 100083 Peoples R China

The Dongying and Zhanhua sags are the major hydrocarbon exploration and produc- tion subbasins in the Bohai Bay Basin. Integrated analysis of the sedimentary basin fills has shown that the syndepositional faults and their arrangement styles exerted an important influ- ence on the development and distribution of the Eogene depositional systems. The sedimentary filling evolution of the subbasins reflects the general control of the episodic rifting process. The major long-term active normal faults formed a series of paleogeomorphic accident or slopebreak zones that commonly delineated the subsidiary palaeostructural units and the depositional facies tracts and constrained the general distribution of sedimentary facies zones. The central sag boundary fault slopebreak zones usually determined the distribution of the depocenters of ter- restrial clastic depositional systems, particularly the lowstand fans or deltaic depositional sys- tems, and have proven to be the economically important targets for the exploration of subtle sandstone reservoirs. A variety of syndepositional fault arrangement patterns, including the par- allel, en echelon, combo-like, broom-like fault systems and the fault overlap or transfer zones, have been recognized in the subbasins. They generated distinctive geomorphic features and exerted a direct influence on sediment dispersal and sandbody distribution during the Eogene synrift stage. It is the key for the prediction of depositional systems tracts and reservoir sand- stones to investigate the activity and distribution of the fault slopebreak zones and reconstruct the structural paleogeomorphy in different basin filling stages of the basin evolution.

关键词： episodic rifting, fault slopebreak zone, depositional pattern, Bohai Bay Basin.

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

Energy analysis for damage and catastrophic failure of rocks

引用

Science China(Technological sciences) 2011年第S1期54卷 199-209页

作者： XIE HePing 1,2.LI LiYun 2.1,JU Yang 2.PENG RuiDong 2.& YANG YongMing 2.1 Sichuan university,Chengdu 610065,China 2.State Key Laboratory of Coal resources and Safe Mining,{2. Key Laboratory of Fracture and Damage Mechanics of Rock and Concrete,China university of Mining and Technology,{2. 100083,China 1. Sichuan university Chengdu 610065 China 2. State Key Laboratory of Coal resources and Safe Mining Beijing Key Laboratory of Fracture and Damage Mechanics of Rock and Concrete China University of Mining and Technology Beijing 100083 China

The development history and current state of studies on the characteristics and mechanisms of deformation and failure of rock materials were briefly reviewed from the viewpoint of *** main scope and the achievable objectives of the energy-based research system were *** was validated by experiments that the damage process of rocks can be well described by the rock damage evolution equation established based on energy *** was found from the uniaxial compression and biaxial compression tests that only a small proportion of the total input energy in hard rocks is dissipated before peak load and a large proportion in soft rocks is dissipated before peak *** both hard and soft rocks,the energy dissipated after peak load accounts for a greater *** energy would be required for rock failure under equal biaxial compression than under unequal biaxial *** total absorbed energy is different for rock failure under high-rate loading and low-rate *** fragmented failure pattern usually corresponds to higher energy *** mesoscopic analysis on the damage and failure of bedded salt rocks showed that the energy dissipation is prominent and the total absorbed energy for rock failure is low when cracks propagate in the weak mud interlayer while it is contrary when cracks propagate in the salt *** energy accumulation,transfer,dissipation and release during the failure process of tunnel with impending failure under disturbance were analyzed theoretically based on the elastoplastic mechanics ***,the spatial distribution of energy dissipation and energy release of fractured rocks under unloading was simulated *** was demonstrated that energy is likely to be released from the weakest surface under compression,which triggers the global failure of rocks.

关键词： rock deformation failure energy accumulation energy dissipation energy release

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：