检索结果-南通市图书馆

Water demand for ecosystem protection in rivers with hyper-concentrated sediment-laden flow

Science china(Technological Sciences) 2004年第z1期47卷 186-198页

作者： LUO Huaming, LI Tianhong, NI Jinren & WANG Yudong Department of Environmental Engineering, Peking University, Beijing 100871, china The Key Laboratory of Water and Sediment Sciences, ministry of education, Beijing 100871, china Peking Univ Dept Environm Engn Beijing 100871 Peoples R China Key Lab Water & Sediment Sci Minist Educ Beijing 100871 Peoples R China

Sediment transport is one of the main concerns in a river system with hyper-concentrated flows. Therefore, the water use for sediment transport must be considered in study on the water demand for river ecosystem. The conventional methods for calculating the Minimum Water Demand for River Ecosystem (MWDRE) are not appropriate for rivers with high sediment concentration. This paper studied the MWDRE in wet season, dry season and the whole year under different water-and-sediment conditions in the Lower Yellow River, which is regarded as a typical river with sediment-laden flows. The characteristics of MWDRE in the river are analyzed. Firstly, the water demand for sediment transport (WDST) is much larger than the demands for other riverine functions, the WDST accounts for the absolute majority of the MWDRE. Secondly, in wet season when the WDST is satisfied, not only most of the annual incoming sediment can be transported downstream, but also the water demands for other river functions can be satisfied automatically, so that the MWDRE in wet season is identical to the WDST. Thirdly, in dry season, when the WDST is satisfied, the water demands for other river functions can also be satisfied, but the low sediment transport efficiency results in significant waste of water resources. According to these characteristics and aiming at decreasing sediment deposition in the riverbed and improving the utilization efficiency of water resources, hydrological engineering works can be used to regulate or control flow and sediment so that the sediment incoming in dry season can be accumulated and be transported downstream intensively and thus efficiently in wet season.

关键词： sediment-laden flow, the Lower Yellow River, water demand for river ecosystem, water demand for sediment transport

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 numerical method for determining the stuck point in extended reach drilling

引用

Petroleum Science 2011年第3期8卷 345-352页

作者： Sun Lianzhong Gao Deli Key Laboratory of Petroleum Engineering Ministry of Education China University of Petroleum Beijing 102249 China

A stuck drill string results in a major non-productive cost in extended reach drilling engineering. The first step is to determine the depth at which the sticking has occurred. Methods of measurement have been proved useful for determining the stuck points, but these operations take considerable time. As a result of the limitation with the current operational practices, calculation methods are still preferred to estimate the stuck point depth. Current analytical methods do not consider friction and are only valid for vertical rather than extended reach wells. The numerical method is established to take full account of down hole friction, tool joint, upset end of drill pipe, combination drill strings and tubular materials so that it is valid to determine the stuck point in extended reach wells. The pull test, torsion test and combined test of rotation and pulling can be used to determine the stuck point. The results show that down hole friction, tool joint, upset end of drill pipe, tubular sizes and materials have significant effects on the pull length and/or the twist angle of the stuck drill string.

关键词： Extended reach drilling stuck pipe torque and drag numerical method

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

Formation of superthick Al-based amorphous ribbon

引用

Chinese Science Bulletin 2003年第19期48卷 2145-2147页

作者： WANG Shenghai, BIAN Xiufang & JIA Yubo Key Lab of Liquid Structure and Heredity of Materials, ministry of education of china, South Campus of Shandong University, Jinan 250061, china Key Lab of Liquid Structure and Heredity of Materials Ministry of Education of China South Campus of Shandong University China

The Al-Ni-La-Ce-Pr-Nd amorphous ribbon with a super-thickness of 140 mm has been produced by the melt spinning technique. The thickness is as twice as that achieved by the melt spinning technique in the corresponding period (the largest thickness of 65 mm). The crystallization was characterized by using a differential scanning calorimetry. The activation energies are calculated based on the Kissinger equation and the effects of the La, Ce, Pr and Nd on the glass forming ability of Al-based alloy are discussed in the paper.

关键词：铝基非晶形合金熔体纺丝玻璃成型性能固相反应

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

Relative n-widths of periodic convolution classes with NCVD-kernel and B-kernel

引用

Science china Mathematics 2010年第1期53卷 165-172页

作者： YANG Wei & LIU YongPing School of Mathematical Sciences,Beijing Normal University Laboratory of Mathematics and Complex Systems,ministry of education,Beijing 100875,china 1. School of Mathematical Sciences Beijing Normal University Laboratory of Mathematics and Complex Systems Ministry of Education Beijing 100875 China

In this paper,we consider the relative n-widths of two kinds of periodic convolution classes,Kp(K) and Bp(G),whose convolution kernels are NCVD-kernel K and B-kernel G. The asymptotic estimations of Kn(Kp(K),Kp(K))q a... 详细信息

关键词： relative n-width periodic convolution class NCVD-kernel B-kernel

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

Isolation and characteristics of a novel biphenyl-degrading bacterial strain,Dyella ginsengisoli LA-4

引用

Journal of Environmental Sciences 2009年第2期21卷 211-217页

作者： LI Ang,QU Yuanyuan,ZHOU Jiti,GOU Min School of Environmental and Biological Science and Technology,Key Laboratory of Industrial Ecology and Environmental Engineering(ministry of education,china),Dalian University of Technology,Dalian 116024,china. School of Environmental and Biological Science and Technology Key Laboratory of Industrial Ecology and Environmental Engineering (Ministry of Education China) Dalian University of Technology Dalian 116024 China

A novel biphenyl-degrading bacterial strain LA-4 was isolated from activated sludge. It was identified as Dyella ginsengisoli according to phylogenetic similarity of 16S rRNA gene sequence. This isolate could utilize biphenyl as sole source of carbon and energy, which degraded over 95 mg/L biphenyl within 36 h. The major metabolites formed from biphenyl, such as 2-hydroxy-6-oxo-6- phenylhexa-2,4-dienoic acid （HOPDA） and benzoic acid, were identified by LC-MS. The crude cell extract of strain LA-4 exhibited the activity of 2,3-dihydroxybiphenyl 1,2-dioxygenase （2,3-DHBD） and the kinetic parameters Km was 26.48 μmol/L and Vmax was 8.12 U/mg protein. A conserved region of the biphenyl dioxygenase gene bphA1 of strain LA-4 was amplified by PCR and confirmed by DNA sequencing.

关键词： Dyella ginsengisoli biphenyl biodegradation metabolic pathway biphenyl dioxygenase

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 flexibility on aerodynamic performance of delta wings with different sweep angles

引用

Science china(Physics,Mechanics & Astronomy) 2010年第5期53卷 915-922页

作者： LIU Yang,ZUO LinXuan & WANG JinJun Institute of Fluid Mechanics,Beijing University of Aeronautics and Astronautics and Fluid Mechanics Key Laboratory,ministry of education,Beijing 100191,china 1. Institute of Fluid Mechanics Beijing University of Aeronautics and Astronautics and Fluid Mechanics Key Laboratory Ministry of Education Beijing 100191 China

Force measurement and surface oil flow visualization experiments were conducted in a wind tunnel to investigate the effects of flexibility on aerodynamic performance of delta wings with different sweep *** experimental results indicate that the maximum lift coefficient is increased and the stall angle is delayed as the sweep angle increases for both rigid and flexible *** is also found that the maximum lift coefficients of the flexible wings with a sweep angle from 35° to 50° are higher than those of the rigid *** increment of the maximum lift coefficient in particular achieves 32.9% compared with the case without lift enhancement for the 40° flexible delta ***,the surface oil flow visualization experiments show that the stall of the flexible wing of the moderate low sweep angle is accompanied by helical flow structure,while the vortex bursting appears on the corresponding rigid wing.

关键词： delta wing wing flexibility aerodynamics sweep angle

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

Current advances in the application of proteomics in apoptosis research

引用

Science china(Life Sciences) 2011年第3期54卷 209-219页

作者： WANG LiShun & CHEN GuoQiang Department of Pathophysiology,Key Laboratory of Cell Differentiation and Apoptosis of ministry of education of china E-Institutes of Shanghai Municipal education Commission Chemical Biology Division,Shanghai Jiao Tong University School of Medicine,Shanghai 200025,china 1. Department of Pathophysiology Key Laboratory of Cell Differentiation and Apoptosis of Ministry of Education of China E-Institutes of Shanghai Municipal education Commission Chemical Biology Division Shanghai Jiao Tong University School of Medicine Shanghai 200025 China

Apoptosis,or programmed cell death,is a complex,genetically-determined process involved in the development and maintenance of homeostasis in multicellular *** of apoptosis has been implicated in a number of diseases,including cancer and autoimmune ***,the investigation of apoptotic regulation has evoked considerable *** apoptotic proteins have been shown to be post-translationally modulated,such as by protein cleavage,translocation,protein-protein interaction,and various post-translational modifications,which fall precisely within the range of proteomic ***,contemporary proteomic technologies have achieved significant advances and have accelerated research in functional and chemical proteomics,which have been applied to the field of apoptosis research and have the potential to be a driving force for the *** review highlights some of the major achievements in the application of proteomics in apoptosis research and discusses new directions and challenges for the near future.

关键词： apoptosis proteomics small compound oncogene tumor suppressor

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

Seismic Image Prediction of Cenozoic Reef-Banks in the Northwestern South china Sea

引用

Journal of Earth Science 2012年第4期23卷 597-611页

作者：陈平陆永潮王振峰陈雷 Key Laboratory of Tectonics and Petroleum Resources of ministry of education China University of Geosciences Zhanjiang Branch Company of CNOOC Limited

The Cenozoic reef-banks reservoir in Qiongdongnan （琼东南） basin is one of the most profitable targets worthy of prospecting in the deep water area of the northwestern South china Sea. In this study, the characteristics of organic reef-like reflectors in southern uplift area of Qiongdongnan basin are analyzed based on the latest 2D and 3D seismic data. It is found that reef-like reflectors in Qiongdongnan basin show high-amplitude moundy continuous reflection at the top and the bottom, chaotic reflection inside the reef-like reflector and there is obviously speed difference between reef-like reflector body and surrounding rock. Combining the geological setting of reef and comparative analysis, the reef-like reflectors are considered to be the reef-banks. Furthermore, the results show that there are three kinds of reef structures in the southern uplift area of Qiongdongnan basin： the fault controlling structure, the fault flexure structure and the carbonate ramp structure. Each structure has its own grow-units that can reveal the growth process of the reef in order. The distribution of reef-like reflec- tors in space shows an arc belt pattern. According to this, four reef arc belts are identified, and their spatial trends are thought to have a good relationship with the buried fault. The internal structure con- stitution and the growth state of reef-like reflectors are mainly controlled by the geomorphology and monsoon-ocean current. The result has an instructive significance to oil-gas exploration of organic reef not only in Qiongdongnan basin, but also even in deep water areas of the South china Sea.

关键词： northwestern South china Sea reef-like reflector structure constitute control factor.

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

Surface interrogation mode of scanning electrochemical microscopy for oxidation study of adsorbed CO generated from serine on platinum

引用

Chinese Chemical Letters 2011年第12期22卷 1481-1484页

作者： Chun Cui Huang,Qian Wang,De Bo Xiang,Hui Bo Shao~* Key Laboratory of Cluster Science,ministry of education of china,School of Chemistry, Beijing Institute of Technology,Beijing 100081,china Key Laboratory of Cluster Science Ministry of Education of China School of Chemistry Beijing Institute of Technology Beijing 100081 China

We report a new method for detection and oxidation of adsorbed carbon monoxide(CO;) generated from serine on a polycrystalline platinum ultramicroelectrode（UME） by bromine（Br;） using in situ surface interrogation（SI） mode of scanning electrochemical microscopy（SECM）.In the SI mode,tip and substrate are both Pt UMEs,and CO;on Pt substrate,generated from serine,can be oxidized by the tip-generated Br;giving a positive *** CO;from serine instead of purging CO gas expands the newly introduced reaction of Br;with CO;and further enhances the hope to get rid of CO;on Pt for fuel cells.

关键词： SECM Surface interrogation mode Adsorbed carbon monoxide Serine Pt ultramicroelectrode

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

The inversion of the real kinematic properties of coronal mass ejections by forward modeling

引用

Research in Astronomy and Astrophysics 2011年第2期11卷 237-244页

作者： You Wu 1 and Peng-Fei Chen 1,2 1 Department of Astronomy,Nanjing University,Nanjing 210093,china 2 Key Lab of Modern Astron.and Astrophys.,ministry of education,Nanjing 210093,china Department of Astronomy Nanjing University Nanjing 210093 China Key Lab of Modern Astron. and Astrophys. Ministry of Education Nanjing 210093 China

Kinematic properties of coronal mass ejections （CMEs） suffer from projection effects,and it is expected that the real velocity should be larger and the real angular width should be smaller than the apparent *** attempts have been taken to correct the projection effects,which however led to an inflated average velocity probably due to the biased choice of CME *** order to estimate the overall influence of the projection effects on the kinematic properties of the CMEs,we perform a forward modeling of real distributions of CME properties,such as the velocity,the angular width,and the latitude,by requiring their projected distributions to best match *** a matching is conducted by Monte Carlo *** to the derived real distributions,we found that （1） the average real velocity of all non-full-halo CMEs is about 514 km s-1,and the average real angular width is about 33°,in contrast to the corresponding apparent values of 418 km s-1 and 42.7° in observations;（2） For the CMEs with the angular width in the range of 20°-120°,the average real velocity is 510 km s-1 and the average real angular width is 43.4°,in contrast to the corresponding apparent values of 392 km s-1 and 52° in observations.

关键词： Sun: coronal mass ejections (CMEs) -- methods: statistical -- methods:numerical

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：