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1.
旅游洞穴中气象条件的改变和洞穴保护 总被引：2，自引：0，他引：2
洞穴作为一种旅游资源早已被人们所开发利用。浙江金华双龙洞、桐庐瑶琳洞、建德灵栖洞、杭州灵山洞和兰溪涌雪洞先后对外开放,使洞穴旅游得到更加迅猛的发展并取得了很好的社会效益和经济效益。然而,开发后洞穴内部气象条件的改变及其对洞穴环境可能产生的不利影响未能引起人们足够的重视,这样将势必降低洞穴的环境质量并进而减少其景观功能的使用价值。 相似文献
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用稳定同位素地球化学古温度测定方法，对浙江省临安县瑞晶洞穴石笋进行了古温度研究，结果表明该地区在距今５万年－１万年间古温度有三次较明显的周期变化，最高温度为１４．９℃，最低温度为６．６℃，最大温差为８℃左右，平均温差为３－５℃。用该方法测定的古研究结果与其它方法的古气候研究结果相一致。 相似文献
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本实验对参芪生血颗粒的制备工艺进行研究并对其质量标准进行研究。采用高校液相测定了参芪生血颗粒的含量,色谱柱为Kromasil C18(规格4.6mm×250mm,5μm);乙腈-水(32∶68)为流动相;流速1.0m L·min-1;柱温:30℃。蒸发光散射检测器条件:漂移管温度温度为40℃,气体流量为1.5L/min。 相似文献
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本文采用气相色谱法对替普瑞酮胶囊中替普瑞酮的含量进行测定。方法:石英毛细管柱(0.53 mm×1.0μm,30 m,SE-30);载气:氮气;汽化室温度240℃;检测器温度280℃;柱温220℃。替普瑞酮在0.4～6.4mg.mL-1范围内呈良好的线性关系。本实验具有较好的重现性、加样回收率、精密度。结论:本实验表明此方法分离效果好、方法简便、准确,、专属性好,可用于替普瑞酮片中替普瑞酮的含量测定。 相似文献
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为了筛选出洞穴滴水中可以反映石漠化程度的指标,对朝营小流域处于石漠化条件下2个洞穴的滴水进行了为期1a的动态监测,分析滴水的物理性质和化学成分。结果表明:所选洞穴的滴水水温变化较一致,并受当月的大气平均温度影响显著;滴水滴率与降雨量有关,且受植被-土被覆盖度以及基岩厚度的共同制约;石灰岩地区的洞穴,石漠化程度低的地区滴水pH值偏小,强度石漠化地区滴水pH值可能存在"雨季高,旱季低"的规律,与潜在石漠化地区及非喀斯特地区洞穴滴水的季节变化规律相反;滴水的电导率与Ca~(2+)含量呈正相关,受大气温度、降雨量、土壤生物源CO_2的影响大,石漠化程度较低的地区,滴水电导率和Ca~(2+)浓度大于石漠化程度高的地区。 相似文献
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辽西地区热量资源分析与栅格化 总被引：16，自引：0，他引：16
利用辽西地区16个气象台站30年(1971年～2000年)的整编温度资料，对辽西地区主要热量资源的现状和变化进行分析，结果表明：在全球变暖的大背景下，辽西地区热量资源变得更加丰富，20世纪90年代年平均气温升幅达0.56℃，≥10℃积温30年间增加了158.5℃。借助GIS技术和数学模拟技术，对辽西地区部分重要的热量资源条件进行栅格化，构建了6种气候要素的小网格推算模型，经过小地形订正，生成为100m×100m空间高分辨率的栅格数据库和相应的专题数字地图，以满足多方面的需求。 相似文献
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本文采用气相色谱法对布洛芬胶囊中布洛芬的含量进行测定.方法:石英毛细管柱(0.S3mm×1.0μm,30m,SE-30);载气∶氮气;汽化室温度230℃;检测器温度270℃;柱温210℃.本实验具有较好的重现性、加样回收率、精密度.结论:本实验表明此方法分离效果好、方法简便、准确、专属性好,可用于布洛芬片中布洛芬的含量测定. 相似文献
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《科技风》2021,(6)
本文采用扫描电子显微镜、直读光谱仪等对冷轧冲压用节镍奥氏体不锈钢盆进行微观组织形貌以及成分的分析。结果表明:基体碳含量偏高是导致不锈钢冲压开裂的根本原因,其主要与连铸阶段的冷却强度、拉速,热轧阶段的加热温度、加热时间等工艺有关。通过数据分析,确立了节镍不锈钢的最佳生产工艺:连铸拉速为1.0～1.2m/min,结晶器宽面冷却强度为2350L/min、结晶器窄面冷却强度370L/min,二冷Ⅱ区冷却强度为170L/min以内,加热炉加一段温度1100℃～1160℃、加二段温度1260℃～1280℃、均热段温度1265℃～1285℃,总时间≥200min。该措施实施后,节镍不锈钢因裂纹导致的脱皮缺陷降级率由14.8%降低至2.4%,为冷轧冲压用奥氏体不锈钢提供了品质的保障。 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