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通过对伊春5个气象站点历史雷暴资料的统计,结合其地理气候特点,分析小兴安岭地区雷暴的空间分布特征、月际、年际变化特征,结果表明,小兴安岭地区雷暴具有明显的局地和时效特征,地形地势是影响该地区雷暴的主要因子;南部地区雷暴日数明显多于中北部;春、夏、秋季是小兴安岭雷暴发生季节,主要出现在夏季,占全年雷暴总日数的76％;雷暴日数的年际差异比较显著,雷暴日数总体上呈减少趋势。 相似文献
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《内蒙古科技与经济》2021,(8)
利用张呼高铁内蒙古段5个气象站月雷暴、降雨、降雪、积雪、大风日数等资料,分析了高铁沿线气象灾害分布特征及对铁路交通的影响,结果表明:气象灾害对高铁运行的影响在路段和时间上存在较大差异,雷暴、强降水和低温是张呼高铁内蒙古段需要重点防范的气象灾害,雷暴和降雨的重点防范期在7月,低温和降雪(积雪)在1月。 相似文献
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根据乌兰地区气象观测站1980～2018年的冻土资料,运用线性回归、累计距平、滑动平均、小波分析法,分析了乌兰地区历年来冻土的变化特征。结果表明:乌兰地区的冻土始冻期和融冻期都呈现提前趋势;最大冻土深度以1.9cm/10a的倾向率呈现递增趋势,冻土日数变化阶段性特征明显,80年代和21世纪前期之后冻土日数高于平均冻土日数,90年代至21世纪初冻土日数持续低于均值;月最大冻土深度只有10月和4月是负增长,其他月份均为逐渐增大的趋势;年最大冻土深度存在2a-4a、6a-10a和14a尺度的周期振荡,1a-2a和6a-8a的周期振荡是控制其冻土日数变化的两个主要时间尺度。 相似文献
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韩丽娜 《内蒙古科技与经济》2023,(6):96-101
对内蒙古自治区119个气象观测站1973年—2021年春季和夏季的逐年、逐月高影响天气(包括高温、大风、沙尘暴、雷暴、降雨、暴雨)日数进行统计分析，并得出其变化趋势及分布特征，结论显示：从年际变化看，1973年—2021年内蒙古地区高影响天气中年高温日数呈显著上升趋势，年大风日数、年雷暴日数呈显著下降趋势，以上均通过了0.05的显著性水平检验，年降雨日数、年沙尘暴日数有减少趋势，但均未通过0.05的显著性水平检验；从月际变化看，高温日数、雷暴日数、降雨日数、暴雨日数最多的月份为7月，大风日数、沙尘暴日数最多的月份为4月；从空间分布看，高影响天气高发区主要集中在内蒙古西部偏西地区、东部偏南地区、中部偏北地区；从突变检验看，高温日数突变年份为1996年，且之后呈现显著增加的趋势；大风日数在1990年后呈现显著减小的趋势，但其发生突变的时间未通过0.05的显著性检验；降雨日数存在突变性，发生突变的年份为1975年、1978年、1981年、1986年、1988年、2013年；雷暴日数突变年份为1994年，且其具有十分显著的减小趋势；沙尘暴日数1979年至今减小趋势十分显著；从Morlet小波分... 相似文献
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本文利用1970～2007年隆子站38a雷暴资料,对历年该地区河谷地带的雷暴分布规律及发生时段进行了统计分析,结果表明:年平均雷暴日数为64.5d,年最多雷暴日数达84d,年最少雷暴日数47d;雷暴集中出现在4～10月,其中68%集中出现在6～8月,94%集中出现在5-9月份;从日变化来看,90%以上的雷暴出现在每日的13～20h,70%的集中出现在13～17h,峰值出现在17h左右,13h之前和20h过后的雷暴10%;雷暴最早出现在3月份,最晚结束在10月份,平均初终间隔日数为170d。 相似文献
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石羊河流域季节性冻土的时空分布及对气温变化的响应 总被引：2，自引：0，他引：2
利用1961-2010年石羊河流域4个气象站点的冻土深度、冻土日数和气温观测数据以及邻近地区气象站点冻土数据,采用气候统计学分析方法,对石羊河流域最大冻土深度和冻土日数的时间演变、空间分布及与气温的关系进行了分析.结果表明: 石羊河流域年代、年最大冻土深度和冻土日数呈显著减少趋势,减少速率分别为4.537cm/10a、6.001d/10a,均通过了а=0.01的显著性水平检验.年最大冻土深度和冻土日数的时间序列分别存在7~8a和8~9a的准周期变化,并发生了突变.冻土主要出现在11月至次年3月,年最大冻土深度几乎都出现在1月和2月,年冻土日数以12月和1月最多.石羊河流域冻土的空间分布与海拔高度、地表植被、地层岩性、土层含水量等局域性因素有关.石羊河流域与冻土同期的年平均气温呈显著升高趋势,上升的速率为0.553℃/10a.年最大冻土深度和冻土日数与平均气温呈极显著负相关,其相关系数分别为-0.7486、-0.8058,气温每升高1℃,冻土深度减小9.3cm,冻土日数减少8.3d;冻土深度和气温具有相同的周期变化,冻土日数的周期变化比气温滞后1a,气温随时间变化对冻土深度和冻土日数随时间变化具有显著负作用.冻土深度的减小和冻土日数的减少可能是对气温升高的响应. 相似文献
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统计分析呼和浩特机场2012-2017年雷暴观测资料,得出呼和浩特年雷暴平均日数为40.6d,初雷日期逐渐提早,最晚终雷日期逐渐退后,但年雷暴次数无明显变化趋势;分析了2017年9月22日的强雷暴天气的发展过程及各气象要素的变化,表明强雷暴过境时,地面风向风速、气温、气压等气象要素均会发生强烈变化,且它们的变化均与雷暴伴随的强降水及冰雹的开始停止及变化时间基本一致。 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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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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《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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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