检索结果-南通市图书馆

STRUCTURAL EVOLUTION OF UNDERCOOLED SINGLE-PHASE Ni-2wt%Pb MONOTECTIC ALLOY

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2001年第1期14卷 72-78页

作者： H.X. Zheng, H. Xie and X.F. Guo (Xi’an university of technology, Xi’an 710048, china) Xi’an university of technology

The structural evolution of undercooled single-phase Ni-2wt%Pb monotectic alloy was systematically investigated by the method of molten glass denucleating combined with superheating cycle. Within the achieved undercooling range of 22 to 280 K, the solidification structure undergoes three changes at 22 K, 88 K and 187 K, respectively. With the increase of undercooling, common dendrites, the first class granular grains, undercooled dendrites and the second class granular grains come out one after the other. Analytical results show that the granulation mechanism of the first class granular grains is owing to dendrite remelting and recrystallization, and the granulation mechanism of the second is owing to dendrite break-up and recrystallization.

关键词： Granulation Lead alloys Microstructure Structure (composition)

Minimal regular 2-graphs and applications

在线全文

学校读者我要写书评

暂无评论

Science china Mathematics 2006年第2期49卷 158-172页

作者： FAN Hongbing, LIU Guizhen & LIU Jiping Department of physics and Computer Science, Wilfrid Laurier university, Waterloo, ON., N2L 3.5 Canada School of Mathematics and System Science, Shandong university, Jinan 250100, {3. Department of Mathematics and Computer Science, university of Lethbridge, Lethbridge, AB., T1K 3.4, Canada Department of physics and Computer Science Wilfrid Laurier University Waterloo Canada School of Mathematics and System Science Shandong University Jinan China Department of Mathematics and Computer Science University of Lethbridge Lethbridge Canada

A 2-graph is a hypergraph with edge sizes of at most two. A regular 2-graph is said to be minimal if it does not contain a proper regular factor. Let f2(n) be the maximum value of degrees over all minimal regular 2-graphs of n vertices. In this paper, we provide a structure property of minimal regular 2-graphs, and consequently, prove that f2(n) = n+3.i/3. where 1 ≤ i ≤ 6, i ≡ n (mod 6) and n ≥ 7, which solves a conjecture posed by Fan, Liu, Wu and Wong. As applications in graph theory, we are able to characterize unfactorable regular graphs and provide the best possible factor existence theorem on degree conditions. Moreover, fa(n) and the minimal 2-graphs can be used in the universal switch box designs, which originally motivated this study.

关键词： graph regular factor 2-graph switch box design.

Spatial Memory Deficit and Tau Hyperphosphorylation Induced by Inhibiting PP2A in Rat Brain

在线全文

学校读者我要写书评

暂无评论

wuhan university Journal of Natural Sciences 2005年第6期 89-93页

作者： TIAN Qing~1,2, ZHENG Hong-yun~1, CHEN Juan~1,LI Hong-lian~1, GONG Cheng-xin~3.WANG Jian-zhi~11. Pathophysiology Department, Tongji Medical college, Huazhong university of Science and technology, {3. 43.03., Hubei, china 2. Medical college, Huangshi college of technology, Huangshi 43.003. Hubei,china 3. The New York State Institute for Basic Research in Developmental Disabilities, Staten Island, New York 103.4, USA

Hyperphosphorylation of Tau in Alzheimer’s disease (AD) brain appears to be caused by a down-regulation of protein phosphatase 2A (PP2A). In this study, we selectively inhibited PP2A by injection of okadaic acid (OA) into the Meynert nucleus basalis of rats and found that 0.4 pmol of OA injection induced approximately 60% inhibition of PP2A 24 h after injection, 13. inhibition 48 h after injection and no obvious inhibition 72 h after injection. Hyperphosphorylation of Tau at Ser-198/Ser-199/Ser-202 and Ser-3.6/Ser-404 and spatial memory deficit of rats were induced 24 h after 0.4 pmol of OA injection. This study suggests that a down-regulation of PP2A may underlie abnormal hyperphosphorylation of cytoskeletal proteins leading to neurofibrillary degeneration in AD.

关键词： protein phosphatase 2A Tau Alzheimer’s disease

Statistical study on the relationship between halo CME and coronal dimming

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science china(Technological Sciences) 2010年第7期53卷 2020-2024页

作者： LIU Kai1, XIA LiDong2, CHEN Yao2 & SONG HongQiang2 1 School of Earth and Space Sciences, university of Science and technology of china, Hefei 23.026, china 2 Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment, School of Space Science and physics, Shandong university at Weihai, Weihai 264209, china School of Earth and Space Sciences University of Science and Technology of China Hefei China Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment School of Space Science and Physics Shandong University at Weihai Weihai China

The data from SOHO/EIT and SOHO/LASCO observations are used to determine the relationship between coronal dimming and full halo CME (coronal mass ejection). The events of full halo CME examined in this study were observed by LASCO co-ronagraphs and taken from the CD AW CME catalog from 1996 to 2008. Dimming events are identified by using difference images taken by EIT at the 195 A passband. We found strong relationship between full halo CMEs and the coronal dimming events, with up to 93.3. of the front-side halo CMEs associated with the EIT 195 A dimming events. Full halo CMEs that show no clear signatures of dimming usually have lower sky plane velocities (<700 km/s) compared to the mean velocity of CMEs associated with dimming.

关键词： Sun coronal mass ejection coronal dimming extreme-ultraviolet

Studies on Barriers for Promotion of Clean technology in SMEs of china

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Population,Resources and Environment 2005年第1期3卷 9-17页

作者： Peng Sizhen , Liu Yan , Shi Han 1 2 & Zhong Ping 3.1. The Administrative Centre for china’s Agenda21, Beijing 100089, china 2. Yale School of Forestry & Environmental Studies, New Haven CT 06511, the U.S.A. 3. Department of Environmental Science and Engineering, Sichuan university, Chengdu Sichuan 610065, china The Administrative Centre for china’s Agenda21 Beijing 100089 China Yale School of Forestry and Environmental Studies New Haven CT 06511 United States Department of Environmental Science and Engineering Sichuan University Chengdu Sichuan 610065 China

After more than 10 years efforts on awareness raising and promotion, the concept of cleaner production (CP) has been adopting as a strategic approach to balance economic benefits and environmental protection for china’s industries. However, it is also found that clean technology is difficult to be adopted and implemented in Chinese Small and Medium-sized Enterprises (SMEs) because of certain barriers. This paper investigates these barriers among three stakeholders--governments, enterprises and experts. The Analytic Hierarchy Process (AHP) was employed to prioritize the relative importance of the twenty fine-selected barriers, which were classified into four barrier categories. The findings reveal that the exterior barriers of policy and financial barriers should be stressed rather than the inner barriers of technical and managerial barriers, although they are also very important. Absence of incentives on economic policies, lax enforcement of environmental regulations and high initial capital cost were the most important barriers to adoption of Clean Technologies (CT) in china.

关键词： Cleaner Production Clean Technologies Barrier Study Small and Medium Enterprises

在线全文

学校读者我要写书评

暂无评论

网络传播的“后现代”特性

武汉大学学报（人文科学版） 2002年第6期55卷 760-766页

作者：秦志希葛丰吴洪霞武汉大学新闻与传播学院湖北武汉430072

电视虽然呈现出后现代的某些特点 ,但只有由电脑技术支撑的互联网才充分显现出后现代的真正来临。互联网技术的成型经历了一个“从大到小”、“从隔离到兼容”、“从集中化到分散化”的过程 ,潜藏着一种消解中心的文化理念。网络传播消... 详细信息

电视虽然呈现出后现代的某些特点 ,但只有由电脑技术支撑的互联网才充分显现出后现代的真正来临。互联网技术的成型经历了一个“从大到小”、“从隔离到兼容”、“从集中化到分散化”的过程 ,潜藏着一种消解中心的文化理念。网络传播消解着传统媒体以传者为主体的“中心———边缘”的传播模式 ,使传播权力发生流变。网络主体行为个性化使得网络语言的述行性颠覆现代语言的各种规则 ,网络叙事则表现了对“元叙事”的“不信任”而倾向于“去中心化”的“小叙事”。

关键词：互联网后现代特性

Heterotrophic bacteria of the Dapeng Bay in the South china Sea: community structure,abundance,and the relationships of culturablity with environmental factors

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2010年第4期29卷 88-97页

作者： JIANG Fajun HU Zhangli HU Chaoqun South china Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou 510301 China Guangxi Academy of Sciences Nanning 530007 China college of Life Sciences Shenzhen University Shenzhen 518060 China

The community composition,abundance and culturablity of heterotrophic bacterioplankton in the Dapeng Bay of the South china Sea were investigated by morphological method,bacterial cultivation and biochemical methods over an annual *** and Pseudomonas were the predominant genera among the Gram-negative *** bacterioplankton abundance fluctuated from 2.07×10 8 to 2.44×10 9 cells/dm 3.,and culturable bacteria abundance ranged between 0.1×10 6 and 16.07×10 6 CFU/dm 3..The Culturablity of heterotrophic bacteria ranged between 0.01% and 1.3.%.The relationship between bacterial culturablity and the environmental factors was also studied in different sites of the Dapeng *** the bay,a significantly positive relationship was evidenced between bacterial culturability and temperature,meanswhile bacterial culturability was significantly inversely related with *** positive relationship was shown at the central bay while a negative relationship was observed at the bay mouth and there was no significant correlation at top bay between bacterial culturablity and chlorophyll a of sea water.A positive relationship was found between culturability and DIN all the bay,but DIP showed a significantly negative relationship with bacterial culturability only at the mouth of the bay.

关键词： heterotrophic bacteria culturable bacteria culturablity environmental factors

Research on the reconstruction method of porous media using multiple-point geostatistics

在线全文

学校读者我要写书评

暂无评论

Science china(physics,Mechanics & Astronomy) 2010年第9期53卷 122-134页

作者： ZHANG Ting 1,2,3. LI DaoLun 1,2 , LU DeTang 1,2 & YANG JiaQing 1,2 1 Department of Modern Mechanics, university of Science and technology of china, Hefei 23.027, china 2 Research Center of Oil and Natural Gas, university of Science and technology of china, Hefei 23.027, china 3.The 28th Research Institute, china Electronics technology Group Corporation, Nanjing, 210007, china university of Science and technology of china Department of Modern Mechanics Hefei China (GRID:grid.59053.3a) (ISNI:***) university of Science and technology of china Research Center of Oil and Natural Gas Hefei China (GRID:grid.59053.3a) (ISNI:***) china Electronics technology Group Corporation The 28th Research Institute Nanjing China (GRID:grid.464269.b) (ISNI:***) university of Science and technology of china Department of Modern Mechanics Hefei China (GRID:grid.59053.3a) (ISNI:***) university of Science and technology of china Research Center of Oil and Natural Gas Hefei China (GRID:grid.59053.3a) (ISNI:***)

The pore structural characteristics have been the key to the studies on the mechanisms of fluids flow in porous media. With the development of experimental technology, the modern high-resolution equipments are capable of capturing pore structure images with a resolution of microns. But so far only 3. volume data of millimeter-scale rock samples can be obtained losslessly. It is necessary to explore the way of virtually reconstructing larger volume digital samples of porous media with the representative structural characteristics of the pore space. This paper proposes a reconstruction method of porous media using the structural characteristics captured by the data templates of multiple-point geostatistics. In this method, the probability of each structural characteristic of a pore space is acquired first, and then these characteristics are reproduced according to the probabilities to present the real structural characteristics in the reconstructed images. Our experimental results have shown that: (i) the deviation of LBM computed permeability respectively on the virtually reconstructed sandstone and the original sample is less than 1.2%; (ii) the reconstructed sandstone and the original sample have similar structural characteristics demonstrated by the variogram curves.

关键词： porous media reconstruction multiple-point geostatistics pore space training image variogram data template

同方期刊数据库

DISSOLUTION EQUILIBRIUM OF Mg VAPOUR IN LIQUID Fe

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 1991年第9期4卷 230-233页

作者： ZHANG Xiaodong HAN Qiyong university of Science and technology Beijing,Beijing,chinaCHEN Dong Hebei Institute of Metallurgy,Shijiazhuang,china Univ of Science and technology Beijing Beijing China

The dissolution equilibrium of magnesium vapour in liguid Fe has been studied in a two-tem- perature-zone furnace at 1600℃ by use of the vapour pressure *** equilibrium con- stant for the reaction Mg_(g)=[Mg] and the... 详细信息

关键词： liquid Fe Mg dissolution equilibrium