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221.
222.
随着城镇化的快速推进,我国经济社会发展进入转型期,乡村地域向多元方向发展和演变。近年来,乡村多功能发展成为地理学研究的重要课题,成为指导乡村转型发展的新理论和新范式。在系统梳理乡村多功能发展概念及其内涵基础上,探索村域尺度下我国乡村地域多功能的类型划分及其评价方法,并开展了江苏省金坛市乡村地域生态功能、农业功能、工业功能、生活功能及其综合功能的分级评价与空间分异研究,进而识别出全市分村域的地域主导功能类型。结果表明:生态功能高值区主要分布在环长荡湖、直溪镇和薛埠镇等水网密集、林地资源丰富的地区;农业功能高值区主要分布在金坛市中部和南部等河网平原地区;工业功能高值区主要集中在中心城区周边和尧塘镇等城市集聚发展区域;生活功能高值区主要集中在中心城区周边等地;乡村地域多功能指数呈现出以城区为中心、向外围逐渐递减的空间分异特征;全市乡村地域主导功能可划分为6种类型,并揭示其空间分布特征、分别总结其所对应的乡村发展策略。研究结果可为明确乡村功能定位、优化主体功能区划、完善乡村管理政策以及促进乡村可持续发展提供科学依据。  相似文献   
223.
借鉴耦合理论,建立了乡镇居民点规模-功能耦合系统,以潼南区为案例,采用熵权法、耦合协调度评价和空间集聚分析等方法,对2014年潼南区22个乡镇居民点规模-功能的耦合协调发展状态进行评价。研究发现,经济规模是乡镇居民点规模的主要决定因素。第三产业是影响居民点生产功能的主要因素,教育医疗则是影响生活功能的主要因素,建成区绿化面积是影响居民点生态功能的主要因素。潼南区乡镇居民点规模-功能耦合协调发展水平在空间上具有明显的单核结构特征,区域发展具有较大的不平衡性。大部分乡镇规模-功能耦合处于拮抗状态,规模滞后状态,规模、功能建设发展都处于低水平状态。应当积极培育县城以外的区域次级增长中心,以缩小区域发展的不平衡性。在村镇居民点的规划中,应重视居民点经济规模的地位与作用,以求更为合理的预测居民点规模,并规划建设居民点功能。  相似文献   
224.
The intent of this research is to investigate how the customers of a technological control laboratory for civil construction materials perceived the quality of the services delivered by the lab, specifically in regard to the service of concrete compression testing. The popular SERVQUAL scale, a multidimensional instrument used to capture customer expectations and perceptions, was used as a model for the application of a survey. Exploratory factor analyses were employed to evaluate customers’ perceptions and experiences of service quality in regard to the dimensions and accompanying attributes of the SERVQUAL scale. Twenty attributes, which were grouped within five dimensions (Reliability, Assurance, Tangibles, Responsiveness, and Empathy), were identified, explaining 80.417% of the variance between customer expectations and perceptions and characterizing these dimensions on a modified SERVQUAL scale. Analysis of the results allowed us to identify discrepancies in perceived service quality compared with customers’ expectations. Most of the identified gaps between expectations and perceptions resulted in negative values.  相似文献   
225.
近地层氮氧化物和臭氧的区域分布研究   总被引:2,自引:1,他引:1       下载免费PDF全文
介绍了近地层氮氧化物和臭氧的区域分布研究方法,使用简化的区域尺度大气污染物传输模型和光化学反应模型,模拟计算了1990年中国主要城市排放氮氧化物的情景下,夏季(7月)主要城市的氮氧化物和相应的臭氧在近地层的浓度分布。   相似文献   
226.
基于分形理论的皖江城市带城镇体系结构研究   总被引:5,自引:0,他引:5  
运用分形理论对皖江城市带城镇体系的规模分布和城镇空间结构进行了具体分析,得出如下结论:在城镇规模分布方面,城市规模结构分布较为集中,中等位序的城市较多,首位城市作用不显著,人口分布低水平均衡;在城镇空间结构方面,城镇之间的空间关联程度、空间相互作用一般,空间布局较分散。在此基础上,提出了未来皖江城市带城镇体系发展的相应对策。  相似文献   
227.
The paper presents a geographic information system (GIS) model-based approach for analysis of potential contamination of soil and water by pyrethroids for the European continent. Pyrethroids are widely used pesticides and their chemical and toxicological characteristics suggest there may be concerns about human health and ecosystems, although so far there is no strong evidence indicating actual risk. However, little monitoring has been conducted and limited experimental information is available. We perform an assessment exercise that demonstrates how accessible information and GIS-based modeling allow to estimate the spatial distribution of chemical concentrations and fluxes at a screening level. The assessment highlights potential hot spots and the main environmental transport pathways, in a quick and simple way. By combining information on pesticide use, crop distribution and landscape and climate parameters we identify potential problem areas to help focusing monitoring campaigns. The approach presented here is simple and fast, and can be applied to virtually all pesticide classes used over a large domain, and is therefore suitable for the screening of large quantities of chemicals, of which the majority has not undergone any systematic environmental monitoring program. The method has been tested through benchmarking with other well-established models. However, further research is needed to evaluate it against experimental observations.  相似文献   
228.
Landscape change alters the visual scale of agricultural landscapes, as production units get larger and strips of taller vegetation are removed between smaller units. Visual scale, defined as the perceptual units reflecting the experience of landscape rooms, visibility and openness, is considered a key factor shaping landscape preference. The visual expression of landscapes affects people in many ways; aesthetic appreciation, health and well being. In order to understand how landscape changes alter the visual scale of landscapes, and hence its effect on human beings, it is important to establish efficient and practical ways of measuring visual scale and its relation to landscape preferences. This paper presents an empirical test of the ability to predict landscape preference of two photo-based indicators of visual scale; percentage open land in the view and size of landscape rooms. A preference survey was conducted with two groups of respondents; a student group from the Norwegian University of Life Sciences (UMB) and a public group. The student group was chosen to represent future landscape professionals. Photos of landscapes varying in the expression of visual scale were shown to survey respondents, who were asked to give scores according to how much they liked the landscapes. Both indicators were found to be predictors of preference for the student group, but not for the public group. The results demonstrate that student preferences do not reflect the landscape preferences of the wider public. The different appreciation of visual scale in the landscape of future landscape professionals and the public implies that experts wanting to reflect preferences of the wider public should be cautious when evaluating the visual impact of landscape change.  相似文献   
229.
A preliminary investigation was performed to estimate the effect of the degree of treatment in Sewage Treatment Plants (STPs) on the status of pollution along the coastlines of the Mediterranean Sea. Data from questionnaires and the literature were collected and processed (a) to identify 18 approximate 1D surface coastal currents, (b) to estimate their prevailing direction and average flow velocity and (c) to estimate the water pollution loads and identify their locations of discharge. Then, a simplified 1D water quality model was formulated and applied for the existing conditions and two hypothetical scenarios: (1) all coastal cities have STPs with secondary treatment and (2) all coastal cities have STPs with tertiary treatment to determine BOD(5), TN and TP concentrations in the 18 surface coastal currents. Calculated concentrations were compared and discussed. A main conclusion is that, to reduce pollution in the Mediterranean Sea measures should be adopted for upgrading the water quality of the rivers discharging into the Mediterranean Sea, along with the construction of STPs for all the coastal cities.  相似文献   
230.
系统安全评价方法对比研究   总被引:3,自引:0,他引:3  
安全评价是衡量风险,实现安全生产的重要途径。为了不同的评价目标开发出来的各种安全评价方法都有其针对性和局限性。认清这些方法的优点和缺点有助于系统地运用安全评价方法衡境目标的风险。安全评价软件有助于弥补安全评价方法的不足,并提高安全评价的效率和可靠性。  相似文献   
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