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991.
为应对地震观测数据量激增以及发报时间要求日趋紧张的情况,作者开发了一个基于Ftp,具有较高效率的上报数据自动传输程序.本文就程序的开发目的、实现方法和实际应用效果进行阐述.  相似文献   
992.
准噶尔盆地荒漠植物碳同位素组成研究   总被引:4,自引:0,他引:4  
通过对准噶尔盆地古尔班通古特沙漠南缘17个科、41个属的53种荒漠植物的稳定碳同位素分析,结果显示准噶尔盆地荒漠植物的叶片稳定碳同位素值在-7.77‰~-30.10‰之间变化,其稳定碳同位素比值分布范围较广,C3和C4植物资源丰富。其中,C3植物有34种,δ13C值分布区间为-23.27‰~-30.10‰,平均值为-26.77‰;C4植物有19种,δ13C值的变化范围为-7.77‰~-14.90‰,平均值为-13.04‰。研究区内木本植物和草本植物的δ13C平均值分别为-16.74‰和-19.81‰,说明木本植物的水分利用效率明显高于草本植物,这种现象可能是全球荒漠生态系统的一种共性。但是一年生草本植物的δ13C平均值(-19.54‰)却高于多年生草本植物的δ13C平均值(-20.07‰),由于植物叶片δ13C可以用来间接指示植物的长期水分利用效率,即δ13C值越大,植物的水分利用效率越高;也就是说在该地区,相对于多年生草本植物而言,一年生草本植物对环境的适应能力较强。  相似文献   
993.
以京津冀3个空间单元为研究对象,建立综合指标体系,利用熵值法计算2005—2015年省域创新效率,运用ESDA和CSDA分析法,详细刻画京津冀创新效率差异的时空演化特征,并分析扩散效应与回流效应在京津冀内部之间的流向。结果表明:京津冀省域创新效率存在正向全局空间自相关,空间聚集特征明显;创新效率在省域之间地理分异特征显著,北京和天津同属于HL型区域,河北则属于LH型区域,基本已形成"中心-外围"的空间格局,不存在收敛特征;创新效率空间结构属于空间滞后模式,存在扩散效应,但扩散效应主要存在于京津之间,河北受京津扩散效应不明显,反而由于回流效应导致与其差距不断增加。  相似文献   
994.
长三角是众多旅游要素的集聚地,高速交通的要素集聚与扩散效应对城市旅游效率增长至关重要.以长三角41市为研究对象,基于多源异构数据构建高速交通与旅游效率评价指标体系,在采用VAR模型验证旅游效率与高速交通关系,以及构建二者耦合机理基础上,综合采用TOPSIS方法、Bootstrap-DEA模型和耦合协调模型对2005-2...  相似文献   
995.
在新一轮西部大开发背景下,旅游业是推动西部区域经济发展的重要动力。基于此,文章综合运用非径向超效率DEA模型、综合线性加权法、非参数Kernel核密度估计、重心模型、重心耦合模型以及VAR模型等方法分析旅游经济效率与区域经济水平的重心耦合与互动响应。研究结果表明:(1)西部旅游经济效率与区域经济水平均处于较低水平,前者经历了从“川-黔-渝”三核到“滇-黔”双核的演变,后者则始终以四川为唯一增长极;(2)旅游经济效率核密度曲线形状从相对平稳发展为陡峭,区域经济水平则相对稳定,前者两极化态势更为严峻;(3)旅游经济效率与区域经济水平重心迁移距离最大方向分别为“南偏西”和“南偏东”,均呈现“西北-东南”极化格局,极化方向分别以顺时针转动了3.41°和1.41°;(4)空间重叠性数值呈“U”型演化,重心耦合态势先“优化”后“劣化”;(5)脉冲响应多呈平滑型响应,响应多集中在前3~4期,区域经济水平对旅游经济效率的方差贡献度较低,旅游经济效率对区域经济水平的方差贡献度较高。  相似文献   
996.
根系分隔对小麦玉米套作田土壤水分状况的影响   总被引:1,自引:0,他引:1  
孔学夫  冯福学  柴强 《中国沙漠》2014,34(3):780-785
2009年3-10月通过田间试验研究了小麦玉米套作田塑料薄膜隔根(PW/C)、尼龙网隔根(NW/C)、不隔根(W/C)及单作玉米(C)和单作小麦(W)的土壤水分状况。结果表明:以单作小麦、单作玉米加权平均为对照,W/C、NW/C和PW/C处理分别显著提高经济产量33.60 %、26.93%和24.69%,增大耗水量-0.2%、1.02%和6.69%,显著提高水分利用效率34.93%、26.67%和17.80%。W/C处理较NW/C和PW/C处理分别提高经济产量5.25%和7.14%,降低耗水量1.21%和6.64%,提高水分利用效率6.52%和14.54%。小麦玉米共生期,土壤水分在套作群体组分间能够优化分配,根系分隔显著降低了作物群体产量及对土壤水分的利用效率。  相似文献   
997.
BOOK REVIEWS     
Book Reviewed in this article: Development and Environment in Peninsular Malaysia . S. Robert Aiken, Colin H. Leigh, Thomas R. Leinbach, Michael R. Moss. The Rural-Urban Fringe: Canadian Perspectives . Ken B. Beesley and Lorne H. Russwurm, eds. Women and Development . Lourdes Benería, ed. The Border that Joins: Mexican Migrants and U.S. Responsibility . Peter G. Brown and Henry Shue, eds. Cities of the World: World Regional Urban Development . Stanley D. Brunn and Jack L. Williams, eds. Time Resources, Society, and Ecology: On the Capacity for Human Interaction in Space and Time (Vol. I, Preindustrial Societies). Tommy Carlstein. Urban Geography . David Clark. Spanish City Planning in North America . Dora P. Crouch, Daniel J. Garr, and Axel I. Mundigo. Not On Our Street: Community Attitudes to Mental Health Care . M. J. Dear and S. M. Taylor Unequal growth: Urban and Regional Employment Change in the U.K. Stephen Fothergill and Graham Gudgin. Agricultural Land in an Urban Society . Owen J. Furuseth and John T. Pierce. The Petroleum Industry in Oil-Importing Developing Countries . Fariborz Ghadar. Historical Understanding in Geography, An Idealist Approach . Leonard Guelke. Regional Planning in Europe . R. Hudson and J. R. Lewis, eds. Remote Sensing for Resource Management . Chris J. Johannsen and James L. Sanders, eds. Geography and The State . R. J. Johnston. Texas Graveyards: a Cultural Legacy . Tlrry G. Jordan. The Politics of Location: An Introduction . Andrew Kirby. A Social Geography of the City . David Ley. Energy and the Future . Douglas MacLean and Peter Brown, eds. The Natural Environment of Newfoundland Past and Present . A. G. Macpherson and J. B. Macpherson, eds. Tourism: Economic, Physical and Social Impacts . Alister Mathieson and Geoffrey Wall. Railroads and Land Grant Policy: A Study in Government Intervention . Lloyd J. Mercer. Progress in Rural Geography . Michael Pacione, ed. Progress in Urban Geography . Michael Pacione, ed. Models of Spatial Inequality: Settlement Patterns in Historical Archaeology . Robert Paynter. Natural Hazard Risk Assessment and Public Policy, Anticipating the Unexpected . William J. Petak and Arthur A. Atkisson. The Nature of Geomorphology . Alistair F. Pitty. Regional Conflict and National Policy . Kent A. Price Women and Spatial Change: Learning Resources for Social Science Courses . Arlene C. Rengert and Janice J. Monk, eds. Urban and Regional Analysis for Development Planning . Richard Rhoda. Rivers: Form and Process in Alluvial Channels . Keith Richards. This Remarkable Continent: An Atlas of United States and Canadian Society and Culture . John F. Rooney, Jr., Wilbur Zelinsky, and Dean R. Louder, gen. eds. The Origins of Open-Field Agriculture . Trevor Rowley, ed. Residential Location Determinants of the Older Population . Gundars Rudzitis. Borderland Sourcebook: A Guide to the Literature on Northern Mexico and the American Southwest . Ellwyn R. Stoddard, Richard L. Nostrand, and Jonathan P. West, eds. Arctic and Antarctic . David Sugden. Tall Timbers Ecology and Management Conference, February 22–24, 1979, Proceedings No. 16 . Graphic Communication and Design in Contemporary Cartography (Progress in Contemporary Cartography , Vol. II). D. R. Fraser Taylor, ed. Living with Energy Shortfall: A Future for American Towns and Cities . Jon Van Til. The United States: Habitation of Hope . J. Wreford Watson. Air Photo Interpretation for Archaeologists . D. R. Wilson. Urban and Rural Change in West Germany . Trevor Wild, ed. Population and Resources . Harry Robinson.  相似文献   
998.
生延超  李辉 《地理科学》2018,38(9):1402-1411
以2003~2014年282个地级以上城市数据作为样本,采用随机前沿生产函数模型测算了中国各城市技术效率,并以互联网规模作为解释变量,构建空间杜宾模型实证检验了各区域互联网对技术效率的影响与空间溢出效应。研究结果表明,互联网规模对技术效率的影响与空间溢出效应存在显著区域差异,分区域检验互联网规模对技术效率的作用是有必要的;互联网规模对中国各区域技术效率具有显著提升作用,但是其提升作用依然较小;东部、中部、西部的城市均受到互联网规模的正溢出效应;东部、中部地区受到技术效率的正溢出效应,西部地区受到技术效率的负溢出效应;分区域检验互联网规模对技术效率的影响及其空间溢出效应,能为推动互联网与经济社会发展深度融合提供有效参考。  相似文献   
999.
Vulnerability research is the core issue and one of the research hotspots of sustainable development science. Vulnerability and its evaluation framework provide a new perspective for rural social-ecosystem studies. This paper introduced the ‘input-output’ efficiency theory and constructed the ‘SEE-PSR’ framework for the analysis of social-ecosystem vulnerability in the rural area in Qingpu District of Shanghai City. The DEA models, spatial autocorrelation model, multivariate logistic regression model, geographical detector and hierarchical cluster model were used to analyze the spatial differences of social-ecosystem vulnerability, and its geographical impact mechanisms and ecological restorations, in 184 administrative villages in this area. The results can be divided into three main points. (1) The results of the ‘input-output’ efficiency model of the EW-DEA based on entropy weight aggregation crossover was more reliable and accurate for the evaluation of rural social-ecosystem vulnerability. The vulnerability of the social-ecosystems in the administrative villages showed a trend of gradual decline from east to west, with an average value of vulnerability of 0.583, and the vulnerability of social systems had become an important factor in constraining the decrease of the vulnerability of the social-ecosystems in the region. (2) The distances from the center of Shanghai City, from Dianshan Lake, from the center of Qingpu District and from the water area were the four dominant geographical factors affecting the vulnerability of the social-ecosystem in this region. The geographical impacts exhibited the spatial differentiations of systemic structure, the substitution of typological attributes and the transformation level. (3) The geographical factors coupling the impact types of the social-ecosystem vulnerability were divided spatially into 10 types. The geographic multi-factor coupling impact types were dominant, which presented multi-cyclic spatial patterns and were dominated by the central multi-factor which was surrounded by the single factor types on both sides. According to the different types, some feasible ways of ecological restoration were proposed, which drew on the experiences of integrated territory consolidation to remediate the vulnerability of rural social-ecological systems. The results of this study can provide scientific reference for rural spatial reconstruction, regional ecological restoration and sustainable development for the regions characterized by conflict in the ‘strict protection of the ecological environment and vigorous development of the economy’.  相似文献   
1000.
In CO2 geological storage (CGS) context, the evolution of the caprock sealing capacity has received increasing attention, particularly on a geological time span (thousands of years). At this time scale, geochemical reactions may enhance or weaken the caprock quality. It is widely recognized that, for the reservoir, geological heterogeneities affect the concentration and spatial distribution of CO2, and then affect the extent of gas–water–rock interactions, which in turn alters the hydrogeological properties of the reservoir. However, much less attention of these effects has been paid to the caprock. In this study, we presented and applied a novel approach to evaluate the effects of permeability and porosity heterogeneities on the alteration of minerals, the associated evolution of the caprock sealing efficiency and the containment of supercritical CO2 (scCO2) within the caprock. Even though this is a generic study, several conditions and parameters such as pressure, permeability, and mineral composition, were extracted from a caprock layer of the Shiqianfeng Formation in the Ordos Basin demonstration site in China. For the sake of simplification, a 2-dimensional model was designed to represent the caprock domain. We firstly generated an appropriate heterogeneous random field of permeability with the average permeability taken from the uppermost mudstone layer of the Shiqianfeng Formation, and then the heterogeneity in porosity was incorporated using a joint normal distribution method based on the available data. Homogeneous mineral compositions of the reservoir and caprock were used in all simulations. Simulations of three cases were performed, including a homogeneous case, a case with only permeability heterogeneity and a case with both permeability and porosity heterogeneities. The results demonstrate dramatic influences of permeability and porosity heterogeneities on the migration of scCO2 within the caprock, the alteration of minerals, and therefore the evolution of the caprock sealing quality. Specific to the data used in this study, hydrogeological heterogeneities facilitated the overall penetration of scCO2 within the caprock and promoted the alteration of minerals, thereby weakening the caprock sealing efficiency over the simulation time.  相似文献   
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