检索结果-南通市图书馆

Tunable chemical complexity to control atomic diffusion in alloys

在线全文

学校读者我要写书评

暂无评论

npj Computational Materials 2020年第1期6卷 1360-1367页

作者： Yuri Osetsky Alexander V.Barashev Laurent K.Béland Zhongwen Yao Keyvan Ferasat Yanwen Zhang Materials Science and Technology Division Oak Ridge National LaboratoryOak RidgeTN 37831USA Department of Nuclear Engineering and Radiological Sciences University of MichiganAnn ArborMI 48109USA Department of Mechanical and Materials Engineering Queen’s UniversityKingstonON K7L 3N6Canada Department of Materials Science and Engineering University of TennesseeKnoxvilleTN 37996USA

In this paper we report a new fundamental understanding of chemically-biased diffusion in Ni–Fe random alloys that is tuned/controlled by the intrinsic quantifiable chemical *** of radiation-tolerant alloys has been a long-standing *** we show how intrinsic chemical complexity can be utilized to guide the atomic diffusion and suppress radiation *** influence of chemical complexity is shown by the example of interstitial atom(IA)diffusion that is the most important defect in radiation *** useμs-scale molecular dynamics to reveal sluggish diffusion and percolation of IAs in concentrated Ni–Fe *** develop a mean field diffusion model to take into account the effect of migrating defect energy properties on diffusion percolation,which is verified by a new kinetic Monte Carlo approach addressing detailed *** demonstrate that the local variations in the ground state energy of IA configurations in alloys,reflecting the chemical difference between alloying components,drives the percolation effects for atomic ***,chemically-biased and sluggish diffusion are phenomena that are directly related to the chemical complexity intrinsically to multicomponent alloys.

关键词： alloys alloying diffusion

Sporopollen analysis of Core B10 in the southern Yellow Sea and the reflected characteristics of climate changes

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2003年第B6期48卷 42-48页

作者： FU Mingzuo~(1,2,3), LI Zhen~1, XU Xiaowei~1 & SHl Xuefa~1 1. Key laboratory of Marine Sedimentology and Environmental Geology, First institute of Oceanography. State Oceanic Administration, Qingdao 266061. china 2. Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071. china 3. Graduate School, Chinese Academy of Sciences, Beijing 100039. china Key laboratory of Marine Sedimentology and Environmental Geology First institute of Oceanography State Oceanic Administration Qingdao China Institute of Oceanology Chinese Academy of Sciences Qingdao China Graduate School Chinese Academy of Sciences Beijing China

Eight sporopollen zones have been divided based on the results of high-resolution sporopollen analysis of Core B10 in the southern Yellow Sea. Based on the results along with ^14C datings and the subbottom profiling data,climatic and environmental changes since the last stage of late Pleistocene are discussed. The main conclusions are drawn as follows: (1) the vegetation evolved in the process of coniferous forest-grassland containing broad-leaved trees→coniferous and broad-leaved mixed forest→coniferons and broad-leaved mixed forest-grassland prevailed by coniferous trees→coniferous and broad-leaved mixed forest-grassland containing evergreen broad-leaved trees→coniferons and broad-leaved mixed forest-grassland prevailed by broadleaved trees→deciduous broad-leaved forest-meadow containing evergreen broad-leaved trees→coniferous and broadleaved mixed forest-grassland prevailed by broad-leaved trees→coniferous and broad-leaved mixed forest containing evergreen broad-leaved trees; (2) eight stages of climate changes are identified as the cold and dry stage, the temperate and wet stage, the cold and dry stage, the warm and dry stage, the temperate and wet stage, the hot and dry stage, the temperate and dry stage, then the warm and dry stage in turn; (3) the sedimentary environment developed from land,to littoral zone, to land again, then to shore-neritic zone; and (4) the Yellow Sea Warm Current formed during early-Holocene rather than Atlantic stage.

关键词：中国黄海气候变化碳14年代测定底基压型数据更新世沉积环境大西洋

Extracting change information of land-use and soil-erosion based on RS ＆ GIS technology

在线全文

学校读者我要写书评

暂无评论

Extracting change information of land-use and soil-erosion b...

The relationship between middle stratiform clouds and large scale circulation over eastern china

5th Asian Symposium on Geographic Information System from Computer Science & Engineering View

作者： LI Zhong-feng~1 LI You-cai~2 (1.Department of resources,Environment and Geography,The Centre for land Study,Peking University,Beijing 100871,P.R.china 2.School of Business Administration,Datong University,Datong 037000,P.R.china)

＜正＞Rapid land-use change has taken place in many arid regions of china such as Yulin prefecture over the last decade due to rehabilitation ***-use change and soil erosion dynamics were investigated by the combined use of remote sensing and geographic information systems（GIS）.The objectives were to determine land-use transi- tion rates and soil erosion change in Yulin prefecture over 15 years from 1986 to *** changes in land- use and soil erosion occurred in the area over the study *** results show the significant decrease in barren land mainly due to conversion to *** land increased associated with conversions from grassland and barren *** area of water erosion and wind erosion *** study demonstrates that the integration of satellite remote sensing and GIS is an effective approach for analyzing the direction,rate,and spatial pattern of land-use and soil erosion change.

关键词： Yulin prefecture RS & GIS land use chang soil erosion

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

The relationship between middle stratiform clouds and large ...

COUPLING SYSTEM OF MAN AND karst

中国气象学会2006年年会“气候变化及其机理和模拟”分会场

作者： Yunying Li1,2 and Hong Gu21 State Key laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid dynamics (LASG), Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, china. 2 Institute of Meteorology, PLA University of Science and Technology, Nanjing,china.

Eastern china is the globally unique land region with lots of middle stratiform clouds in cold seasons. The distribution of this specific stratiform cloud is determined by three main factors, viz, rel

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

中国岩溶 1992年第S1期11卷 230-231页

作者： Yang Hankui Zhu Wenxiao Li PoGuizhou Institute of Mountainous resources,PRC

The 20％ of population in the world live in karst environment, which forms a special system of man and land, i.e., the formation of karst terrain in which people involved. The material flow and energy flow are slow-speed flows in natural karst environment, but they are accelerated by the function of scientific and technological advance in a social-karst environment, The dynamic coupling of two flows form a huge, non-equilibrated and open system,

关键词： karst technological terrain advance accelerated

The seasonal and daily CO_2 concentration variance in karst meadow soil profile with depth in Central Guizhou, china

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1999年第S2期44卷 93-94页

作者： ZHENG Leping~(1,2), LI Tingyu~2, WAN Guojiang~2, WANG Shijie~2 and OUYANG Ziyuan~2 1. Department of Environmental Science and Engineering, Shanghai University, Shanghai 200072, china 2. State Key laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, china Department of Environmental Science and Engineering Shanghai University Shanghai 200072 China State Key laboratory of Environmental Geochemistry Institute of Geochemistry Chinese Academy of Sciences Guiyang 550002 China

THE seasonal variance of soil CO2 concentration with depth in soil profile was widely studied. Few similarresearches on this topic have been done in karst area which comprises 15% global terrestrial area. In thisnote, the research results about the seasonal and daily soil CO2 concentration variance in karst area arereported. The soil gases were collected respectively by the sampling device at 200, 5,0, -5, -10,-15, -25, -35 and -45 cm from the land surface in meadow soil profile described by Zheng andlocated in the Hongfeng lake area in the central Guizhou Plateau which lies in the central East-Asia karstarea. Sampling time is in the morning, midday and at night in April, August and November, 1998 aswell as in January, 1999, respectively. Concentrations （volume percent） of CO2 in soil gas samples

关键词： soil CO2 concentration karst area Guizhou Province.

Research on Formational and Evolutional Processes of Xingwen's Erosive karst Tiankeng

在线全文

学校读者我要写书评

暂无评论

四川地质学报 2009年第S1期 153-159页

作者： SHUI Wei 1,WANG Xing-gui 2,ZHANG Bin 3,SHU Cheng-qiang 3,WEI Ya-li 4 LI Tie-song 3,ZHANG Qi-chun 3,CHENG Jin-ping 4(1.Department of Eco-agriculture and Rural Development,Sichuan Agricultural University,Ya'an 625014,Sichuan 2.Environment and Life Science of Kangding Nationality Teachers College,Kingding 626001,Sichuan 3.School of land and resources,china West Normal University,Nanchong 637002,Sichuan 4.College of resources and Environment,Sichuan Agricultural University,Ya'an 625014,Sichuan)

According to the first-hand investigation and study on Xingwen Global Geopark,the results and the data show that apart from Dayanwan and Xiaoyanwan collapsed karst Tiankeng,there are other karst landforms in Bowang Mount scenic spot such as Feiwu Cave,Dao Cave,Cangshuiyan Gorge,Nanxing TanKeng and so *** typical karst landforms could be regarded as different vestiges of erosive karst Tiankeng of Xingwen Global Geopark,which stand for the evolutional processes of erosive karst Tiankeng ***,the evolutional processes of erosive karst Tiankeng could be divided into the following continuous processes:an erosive karst Tiankeng develops from the processes of eroding and dissolving & extending of silo Sinkhole,and subsequently degrades to a large gorge or *** is worth pointing out that except for erosion of flowing water,at the same time,collapse effect has been playing extremely important role in the forming processes of these special erosive landforms.

关键词： Erosion Evolution Tiankeng Xingwen Global Geopark

The Dynamic Analyses of Coastal land Use Patterns in Inner Lingdingyang,the Pearl River Estuary

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 Dynamic Analyses of Coastal Land Use Patterns in Inner L...

The reconstruction of fossil planation surface in Chin

海洋地质、矿产资源与环境学术研讨会

作者： XIA Zhen CHEN Yunzhen LEI Yong JIA Peihong ( The Key laboratory of Coast & Island Development of ministry of Education, Nanjing University, Nanjing 210093, P. R. china Guangzhou Marine Geological Survey, Guangzhou, 510760 Jiangsu Provincial Survey Bureau, Nanjing, 210013, P. R. china )

To satisfy the growing land demand from economic development, a large scale of land reclamation has been carried out in inner Lingdingyang area in recent years. As a result, the tidal flat and the water channels are narrowed, the frequency of flooding increased and the environment undermined. Guangzhou Marine Geological Survey (GMGS) conducted an integrated project for marine geo-environment & geo-hazards survey in 2003. With the integration of multi-temporal remote sensing (using the images of 1977, 1978, 1988, 1996, and 2003), GIS spatial analyzing approach and GPS technique, as well as field data and other background data of the region, this research investigates the comprehensive characteristics and the drivers of coastal land use dynamics and shoreline changes in inner Lingdingyang area. It is revealed that the reclaimed coastal land was mainly for agriculture and aquaculture in early years, but now they have been converted to construction sites of harbors and industries, especially high-tech industry.

关键词： Inner Lingdingyang, Coastal land Use pattern, Dynamic Analysis

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Chinese Science Bulletin 2002年第5期47卷 434-440页

作者： FENG Jinliang & GUI ZhijiuDepartment of Urban and Environmental Sciences, Peking University, Beijing 100871, china Institute of Geography, Hebei Academy of Sciences, Shijiazhuang 050011, china Department of Urban and Environmental Sciences Peking University Beijing China Institute of Geography Hebei Academy of Sciences Shijiazhuang China

On the basis of results of relative subjects, the fossil planation surface has been discussed by the authors from the point of geomorphologic view. The discussion contents included the characteristic information, research methods, paleotopography (gradient and altitude) and other problems about fossil planation surface. The recognition and reconstruction of fossil planation surface mainly rely on the following characteristic information: (i) the character of erosion unconformity surface; (ii) the paleo-weathering crust and residual deposits; (iii) the paleo-karst and filled deposit in the paleo-karst under the unconformity surface, and (iv) the character and environment of sediment above the unconformity surface. According to the above-mentioned characteristic information, the authors recognized and reconstructed two stages of fossil planation surface on Pa-leo-land of North china and Yangtze Paleo-land. These two fossil planation surfaces formed from Middle Ordovician to Lower Carboniferous and from

关键词： fossil planation surface characteristic information pa-leotopography reconstruction.