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西北地区水资源承载力分析预测与评价 总被引:56,自引:3,他引:56
水资源是干旱、半干旱地区社会经济发展和生态环境保护的关键制约因素,水资源承载力的分析计算和评价是干旱、半干旱地区寻求区域可持续发展道路的重要依据。该文探讨了水资源承载力状况的评价方法,建立了水资源承载力评价指标体系,对各评价指标的可承载极限临界值和理想值进行了界定,建立了水资源承载力模糊综合评判模型,并运用之对西北地区现状年及未来10a、20a、50a不同发展情景方案下的水资源承载状况进行了评价。模型预测结果表明,通过生态环境治理、节水技术进步和产业结构调整等综合措施,未来各年段西北地区水资源承载力状况将逐步改善,其中以采用A1+B2+C2发展情景方案将使水资源承载状况综合效果最佳,节约用水、降低水资源开发利用率,提高用水效率和控制人口增长则是提高西北地区水资源承载力水平的关键因素。 相似文献
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水资源承载力的合理评价对水资源可持续发展有重要的指导意义。本文采用可变集理论建立了水资源承载力可变集评价模型,构建了陕西省水资源承载力综合评价指标体系,应用该模型从纵向和横向两个维度对陕西省水资源承载力进行综合评价,并提出相应的水资源承载力提升策略。研究结果表明:本文构建的基于可变集理论的水资源承载力评价方法,能够较好的描述水资源承载力的稳定状态和变化趋势,研究样本的分析结果证实了陕西省水资源承载力近几年呈稳步上升趋势,但空间分布不均衡的问题比较严重的现实情况,验证了该模型合理性和客观性。 相似文献
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北京市水资源政策对水资源承载力的影响研究 总被引:14,自引:0,他引:14
在对北京市水资源承载力特征及其影响政策分析的基础上,提出用系统动力学(SD)来定量研究不同政策对水资源承载力的影响.在水资源合理配置的前提下,以北京市社会经济环境系统为研究对象,建立北京市水资源系统动力学模型,并将水资源承载力指标融合在模型中进行计算.通过动态仿真模拟,预测北京市5项水资源政策--实施应急供水工程、推进再生水回用、调整工业产业结构、发展农业节水灌溉和提高用水价格对水资源承载力的长期影响,为确保北京市用水的长期安全和社会经济的持续发展提供科学的决策依据.研究表明,应急供水工程政策对北京市水资源承载力的影响最大,而若同时实施这5项政策,到2010年,可承载的工业总产值、农业总产值和非农业人口将分别达到9 663×108元、417×108元和1 527×104人. 相似文献
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水资源短缺与水环境恶化已成为京津冀经济社会可持续发展的主要制约因素,水资源承载力评价是区域水资源合理配置的关键。本文从水资源系统对经济、社会系统的支撑角度出发,选取11个主要影响水资源承载力系统的因素作为评价指标,建立了基于水量、水质、水域、水流的水资源承载力评估方法,研究外调水对京津冀水资源承载力的影响。结果表明京津冀地区水资源承载力都属超载,天津、北京尤为严重。京津冀地区水资源承载的压力主要来自于水资源系统,水资源短缺是京津冀水资源承载力超载的主要因素,人均水资源量是影响区域水资源承载力的关键因子。外调水对改善京津冀水资源承载力具有一定贡献,尤其是对北京、天津的影响较为显著。在水资源短缺时期外调水的影响更为明显,在2000年特枯年,天津市引滦与引黄入津使得水资源承载力提高了13%。南水北调使得2015年北京、天津两地水资源承载力分别提高了5%。外调水对水资源承载力影响研究为京津冀水资源的合理利用提供了依据,对于实现水资源与经济社会的协调发展具有重要意义。 相似文献
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水资源短缺已成为制约滇中城市群发展的主要因素之一,客观认识水资源生态承载力及其平衡性是解决滇中城市群缺水问题和实现区域社会-经济-生态协调发展的前提。运用水资源生态足迹模型、基尼系数以及重心模型对滇中城市群水资源生态承载力的供需平衡、时空平衡以及平衡性的偏离程度进行分析。结果表明:①2006-2014年滇中城市群水资源生态承载力为(0.216~1.370)hm2/人,区域内部差异和年际变化较大;②水资源生态承载力在供需上呈现不平衡状态,在时间变化上呈现不稳定状态;③水资源生态承载力的综合基尼系数为0.372~0.626,总体上处于“集聚程度较大”的区间范围,空间变异系数为0.358~0.804,水资源生态承载力在空间分布上不平衡;④滇中城市群水资源生态承载力重心与其几何中心偏离,偏向南部地区,年均偏移距离为40.6km,区域间水资源生态承载力与人口、经济分布以及资源环境极不对应。 相似文献
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基于量-质-域-流的京津冀水资源承载力综合评价 总被引:1,自引:0,他引:1
京津冀地区人均水资源占有量低,用水压力大,水资源问题突出,因此亟需对该地区进行水资源承载力综合评价研究,以期为水资源综合规划与高效利用、区域可持续发展等提供一定的理论基础与实践经验。为此,首先对京津冀水资源利用情况进行分析,提出了京津冀水资源所面临的问题,以问题为导向;其次对水资源承载系统进行解析,构建基于量-质-域-流内涵的京津冀水资源承载力综合评价指标体系;最后利用AHP、熵权法对评价指标进行主客观组合赋权,借助TOPSIS评价模型对水资源承载力进行综合得分计算。结果表明:①京津冀地区水资源总量匮乏,水资源过度开发利用,地下水持续超采等已经导致该地区水生态功能退化,形成了集中连片的地下水漏斗区等;②通过对研究区水资源承载力评价计算,2006—2016年京津冀水资源承载力综合评价得分总体上呈现波动式增长态势,表明水资源承载力有所增强,但整体分值不高,水资源压力形势依然严峻。基于此,京津冀亟需构建区域、流域水资源联动机制,以京津冀协同发展为契机,针对不同地区的发展基础与城市定位,遵循“以水量城”的城镇化政策和“以水定产”的产业政策,深入贯彻最严格的水资源管理条例,实现整个区域水资源承载力的提升。 相似文献
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A research group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol-a chemical found in the skins of red grapes in red wine-can improve the sensitivity of mice to the hormone insulin according to a report in the October issue of Cell Metabolism.…… 《中国科学院院刊(英文版)》2008,22(1):14-15
Aresearch group led by Prof. ZHAI Qiwei from the Institute for Nutritional Sciences under the CAS Shanghai Institutes for Biological Sciences has discovered that even relatively low doses of resveratrol--a chemical found in the skins of red grapes and in red wine--can improve the sensitivity of mice to the hormone insulin, according to a report in the October,2007 issue of Cell Metabolism. As insulin resistance is often characterized as the most critical factor contributing to the development of Type 2 diabetes, the findings“provide a potential new therapeutic approach for preventing or treating” both conditions, the researchers said. 相似文献
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Marjorie Armstrong-Stassen Margaret Landstrom Ramona Lumpkin 《The Information Society》1998,14(2):153-164
This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors. 相似文献
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A joint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology his co-workers from Norway US Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells suggesting that China's projected climate warming could decrease the pest's numbers. The study was published in Proceedings of the National Academy of Sciences on September .…… 《中国科学院院刊(英文版)》2008,22(1):6-7
Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China's projected climate warming could decrease the pest's numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007. 相似文献
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Active biological molecules functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery disease diagnosis therapy new nanodevice construction.…… 《中国科学院院刊(英文版)》2008,22(1):22-22
Active biological molecules and functional structures can be fabricated into a bio-mimetic system by using molecular assembly method. Such materials can be used for the drug delivery, disease diagnosis and therapy, and new nanodevice construction. 相似文献
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Caroline Haythornthwaite 《The Information Society》2001,17(3):211-226
A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction. 相似文献
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《中国科学院院刊(英文版)》2008,22(1):2-3
CAS should stick to the principle of rendering service to, and giving impetus for, the development of China's science enterprise by making S&T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party's Leading-member Group at CAS, which was held from 7 to 11 January in Beijing. 相似文献
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《中国科学院院刊(英文版)》2008,22(1)
With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants." 相似文献
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Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies. 相似文献
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Leah A. Lievrouw 《The Information Society》2000,16(2):155-159
This essay focuses on universal service and the Internet as means to support social and political participation. The emphasis on access to telecommunications systems in conventional approaches to universal service is contrasted with access to content. A model of the information environment is described that accounts for the roles of content and conduit, both of which are necessary conditions to achieve true access. A method is outlined for employing information indicators to observe or measure the information environment. 相似文献
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Puay Tang 《The Information Society》1998,14(1):19-31
The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means. 相似文献