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中国新农村建设的核心是构建现代农业体系，而现代农业是以农业产业化、规模化为主要标志。农业规模化首先依赖于土地资源规模化潜力的大小。土地资源空间格局和地形是土地资源规模化潜力的两个核心指标。本文探讨了利用地形指标，景观丰度指数、斑块方度指数、景观集中度指数等景观格局指数作为土地资源规模化潜力评价的方法，结合DTM提取的地形坡度因子，以地形起伏较大的喀斯特山区耕地资源为例，应用GIS技术定量分析了不同地形区包括喀斯特河谷区和喀斯特峰林峰丛山区耕地资源规模化潜力指数和规模化成本。结果表明，地势平坦的喀斯特河谷区的耕地规模化潜力综合指数为0.91，地形复杂的喀斯特峰丛峰林山区为0.28，前者为后者的3倍多，而后者的耕地规模化机械成本消耗是前者的8.8倍。说明土地资源规模化潜力和规模化成本受到土地资源空间格局和地形格局的严重制约，且严格受控于土地资源空间格局与地形的组合形态，不同的地形区域之间差异巨大，将对区域农业现代化发展有重要影响。 相似文献
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南美洲古老农业文明孕育的暗色肥沃土壤引发了全球生物质炭研究热潮。将农业生产过程中产生的有机废弃物经过低温热裂解技术转化为生物质炭并施用于农田土壤中,是一种新的土壤可持续管理途径,且服务于生物质废弃物治理与生态农业。我国生物质炭工业化生产技术及炭基肥制备与施用技术已经形成,土壤增碳与农业增产、减肥、增效潜力显著。大规模生物质炭工业化生产的推广催生了一个新兴的科技领域——生物质科技与工程。该科技服务于中国巨大的生物质废弃物治理和土壤改良、化肥减量及绿色农业等需求,这一学科领域尚待系统整合和提升。文章提出,研究生物质炭的有机质组分、结构、性质与功能的表征与有机质-矿物-微生物相互作用的基础研究是未来土壤可持续管理中的重要研究方向。这些问题将揭示生物质炭对于农业生命的系统健康及绿色农业的巨大价值,也进一步彰显了土壤学服务于中国农业可持续管理与生物质产业融合的巨大价值。 相似文献
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宋开慧周景月张培栋阚士亮 《中国科技论坛》2016,(1):124-129
利用2012年宏观数据,探究中国生物质资源的省域分布及发电潜力阈值,构建生物质发电潜力指数(BPGI)指标体系,评价各省(区、市)生物质发电的发展水平及潜力,并结合省级电网碳排放强度对各省规划装机目标配额进行优化。结果表明:2012年中国生物质发电潜力阈值为1.612×105MW/年;河南、黑龙江、山东位列前三,可承担中国"十三五"期间24.10%的生物质发电目标装机量;上海、北京、浙江等地可通过资金输出间接承担。为促进中国生物质发电产业的布局优化、合理开发提供参考。 相似文献
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本文提出一种新的生物质水煤浆技术,利用棕榈油废水和棕榈油固体废物生产生物质水煤浆。该技术提高能源利用率的同时,解决了棕榈油废水处理问题,避免传统处理方式的二次污染和高治理费用,使废液中的可燃物得到充分利用,实现棕榈油生产伴生的固、液废弃物的资源化回收利用。 相似文献
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甘蔗作为生物能源作物的潜力分析 总被引：3，自引：0，他引：3
基于目前世界性的石油危机现状,本文分析了甘蔗在中国作为可再生生物质能源作物的必要性及可能性。甘蔗是C4作物,其光能转换效率、光合速率、单位面积生物产量显著高于其它作物,并具有高净能比,适应性广,耐旱,产量潜力大,用甘蔗加工生产酒精成本低,而且巴西利用甘蔗大规模生产能源酒精取代汽油已相当成功,因此认为甘蔗是中国最有潜力的生物能源作物。中国需要重视能源甘蔗品种的选育,加强甘蔗能源酒精生产工艺的研究与开发,并相适应的展开酒精汽油燃料动力机械的研制。可以展望,利用甘蔗发展能源酒精生产具有广阔的前景。 相似文献
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<正>生物质具有可再生性,并且十分丰富,每年生产量远远超过目前世界能源需求总量,相当于世界年能耗总和的10倍。因而,生物质成为仅次于煤炭、石油和天然气的世界第四大能源。生物质可以通过微生物发酵生产沼气、压缩成型固体燃料、气化生产燃气/发电/供热、生产燃料酒精、生产生物柴油等方式进行转化和利用,应用在国民经济的各个领域。随着化石能源的日趋枯竭和人类对全球性环境问题的重视,生物质能替代化石能源利用的研究和开发,已成为国内外众多学者研究 相似文献
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信息技术是指利用电子计算机和现代通讯手段获取、传递、存储、处理、显示信息和分配信息的技术。多媒体技术应用于体育教学中已成为一种趋势；信息技术在体育训练中主要应用于训练数据采集与管理、运动技术分析与仿真及运动训练辅助系统的开发与应用，在这方面已显示出了较好的发展势头和巨大的潜力；信息技术应用于体育竞赛中不仅能够最大限度的保证体育比赛的公正公平，还能将体育比赛的魅力和影响力进一步推广；在国内外的相关研究中，国外在此方面的研究大多数都是从微观的角度出发，具有很强的操作性和实用性，国内在此方面的研究主要集中在技战术分析方面。 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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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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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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《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