共查询到20条相似文献，搜索用时 843 毫秒
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立足已广泛使用的IDR／IBS体制，从诸多参数的概念入手，深入的论述了卫星通信中载噪比、信噪比与误码率的关系，以及如何利用频谱分析仪准确测量接收卫星信号的载噪比。通过测试分析，最后指出不能为降低误码率而刻意提高（C0＋N0）／N0，必须经过认真的测试调整，寻求两者之间的最佳值。 相似文献
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说明:这是一套形式新颖、有趣的花样体操,它用形象的动作体现了幼儿在园的部分活动,融锻炼身体、品德教育、娱乐为一体,对幼儿身心的健康发展很有益处。第一节好孩子有礼貌(头部运动) (四个八拍,以下均同) 预备姿势:立正。①～④拍:踏步拍手点头,头一拍一次左右侧点,拍手方向与点头方向一致。⑤～⑥拍:两手食指指脸,同时头左右侧点各一次。⑦～⑧拍:两手斜向下放在身后,敬礼(前点头)一次后还原。后三个八拍可变换敬礼方向,小朋友互 相似文献
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谢祥娟 《临沂师范学院学报》2014,36(4):114-118
比较句一般来说分为三种:平比句、差比句和极比句。马建忠指出,差比者,两端相较有差也。差之之字,概为"於"字,"于""乎"两字亦间用焉。《晏子春秋》中的差比句共26例,根据比较词的不同,可以分为"于"字句、"如、若"字句以及"与……孰"构成的差比问句三类。我们分别从比较主体、比较基准、比较结果、各句式中使用的副词以及不同形式等方面对这些差比句式进行了细致而深入的研究,最终,对《晏子春秋》差比句式的使用情况有了一个比较全面的认识。 相似文献
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从一个求交比的例题分析了交比求解中常出现的错误解法,总结交比教学中应注意的事项,归纳出点列交比求解的方法。 相似文献
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引言:比字句的研究现状汉语的比字句是现代汉语中差比的主要格式,它的发展和演变经过了长期的过程,以前这方面的研究主要有黄晓惠(1992)、史佩信(1993)、李讷、石毓智(1998)等。 相似文献
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DENG Jia mei CAO Jia lin LI Ming LI Ping * YU Ying 《上海大学学报(英文版)》1999,3(3):218-222
１ Ｉｎｔｒｏｄｕｃｔｉｏｎ ＩｎｔｈｉｓｐａｐｅｒｓｏｆｔｉｎｓｏｆｔｏｕｔＭＡＰｄｅｃｏｄｉｎｇａｌｇｏｒｉｔｈｍｓｂａｓｅｄｏｎｔｈｅｆａｓｔＨａｄａｍａｒｄｔｒａｎｓｆｏｒｍ（ＦＨＴ）ａｒｅｄｅｖｅｌｏｐｅｄ,ａｎｄｔｈｅｉｒａｐｐｌｉｃａｔｉｏｎｓｉｎｄｅｃｏｄｉｎｇｌｏｗｒａｔｅｍｕｌｔｉｄｉｍｅｎｓｉｏｎａｌｃｏｎｃａｔｅｎａｔｅｄＨａｄａｍａｒｄｃｏｄｅｓａｒｅｅｘａｍｉｎｅｄ．Ｔｈｅｐｒｏｐｏｓｅｄｍｅｔｈｏｄｈａｓａｎｏｔａｂｌｅａｄｖａｎｔａｇｅｏｆａｃｈｉｅｖ… 相似文献
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David Turner 《International Review of Education/Internationale Zeitschrift für Erziehungswissenschaft/Revue internationale l'éducation》2004,52(3):347-357
Since the early 1950s, the axis centralisation–decentralisation, especially as thematised in the work of Isaac Kandel, has represented a major focus of comparative studies in education. Kandel argued that issues relating to the internal conduct of the classroom (interna ) should, so far as possible, be decentralised, while issues relating to administration, school structure and organisation of the educational system (externa ) might safely be centralised. After 1988, successive governments in the United Kingdom have undertaken reforms which have placed more central control on the curriculum and even methods of teaching (interna ), while school finance and administration (externa ) have been devolved to the school level. The present essay argues that a simplistic approach to centralisation and decentralisation is not likely to be fruitful. Instead, we should acknowledge the role of the State in creating a permissive framework for educational systems. Local action can then be seen as part of a policy accommodating or resisting the implications of that framework. 相似文献
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简要介绍了霍乱毒素B亚单位（CTB）佐剂的作用方式、免疫途径及CTB－融合蛋白的免疫原性，大量实验证据表明，CTB是一种具有良好应用前景的粘膜免疫佐剂。 相似文献
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惠萍 《广东教育学院学报》2009,29(5):54-58
利用B样条技术计算类氢施主杂质量子环能级和束缚能的量子尺寸效应．计算结果表明：量子环的能级E1随着抛物势ωh的增加而增大．E1-R0曲线存在极小值,极小值的位置r00随着ωh的增加而减小．束缚能Eb随着量子环半径r0的增加而单调快速地下降．在r0〈60nm区域,E1和Eb的量子尺寸效应很明显．在r0〉60nm区域,E1和Eb的量子尺寸效应不明显;在r0〈70nm区域,随着角动量m。从0增加到3,E1-r0和Eb—r0曲线的斜率发生剧烈的变化,E1的极小值的位置r00随着mc的增加而快速增大．在r0〉80nm区域,E1-r0和Eb-r0曲线分别会聚成一条线,E1和Eb不依赖于mc值的变化而变化;随着施主杂质的电荷增大,能级E1快速下降,E1-r0曲线的极小值的位置r00明显减小．库仑能不可以作为微扰项来处理． 相似文献
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Paul L. Williams 《Educational Measurement》1988,7(2):18-20
Presenting a view from CTB/McGraw-Hill, the author discusses the time-bound nature of test norms and argues that the phenomenon of most elementary students' scoring above averages from previous years' norms is a result of generally increasing levels of achievement. 相似文献
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分析了我校现有的CATV有线电视分配系统所存在的设备与技术上的落后与不足．在此基础上提出了一套技术先进、价格合理的升级改造方案,对CATV设计调试中的几个主要技术参数如C／N、CM、IM和CTB作了准确地计算. 相似文献
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XM L技术广泛应用于数据库和在网络传输。但是XM L主要适用于文本数据,所以对于图形数据一般是分开传输的,从而改变了传输的统一性。本文提出了一种简单高效的图像转换的方法,从而实现了图像在XM L中的传输。 相似文献
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从关于学习的评价到为了学习的评价 总被引：5，自引：2，他引：3
为了学习的评价近些年来在评价研究和实践中日益被广泛接受。本文介绍了为了学习的评价的基本概念、应用为了学习的评价的主要策略和原则,并将其与关于学习的评价进行了比较。通过将剑桥评价和CTB的两个为了学习的评价的产品作为例证,作者建议专业化考试机构应该在关于学习的评价之外推进为了学习的评价以服务于教育。 相似文献
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针对企业级JavaEE应用现有数据访问层解决机制,提出一种轻量级、可重用的数据访问层组件实现方案。方案基于XM L －关系数据映射和转换,数据库模型组件针对关系数据库表、视图进行建模,数据库访问控制组件和SQL动态构建组件根据数据库模型组件,结合XML格式数据,动态构造数据库存取SQL语句。项目实验表明,可以快速构建企业级JavaEE应用系统的数据访问层,提高系统可维护性和扩展性。 相似文献
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FAN Bing WANG Xiao-ying LI Miao ZHANG Yu-dong ZHANG Bao-cui LUO Jian 《重庆大学学报(英文版)》2013,12(4):147-154
The aim of this study was to compare differences in imaging quality at different injection rates of gadobutrol(Gadovist? 1.0M) for dynamic supra-aortic imaging by contrast-enhanced magnetic resonance angiography(CEM RA). In 6 healthy volunteers,dynamic CEM RA examinations were performed twice at a 7 d interval with a gadobutrol dose of 0.1 mmol given to 1 kg body mass. For the two examinations,the contrast medium was injected at rates of 1.5 mL/s and 2.0 mL/s,followed by 20 mL normal saline injected at the same rate. Using a GE Signa 3.0T M R apparatus and the time-resolved imaging of contrast kinetics(TRICKS) technique,scanning was performed continuously for 15 phases at a time resolution of about 2.4 s. Vascular reconstruction was undertaken by multiplane reconstruction and maximum intensity projection techniques. Two radiologists experienced in CEM RA diagnosis subjectively evaluated the contrast effect,vascular detail,and pseudo-shadow of all images,and graded them via a 5-point scale. With the two drug injection rates,the image quality,peak signal-to-noise ratio(SNR) and contrast-to-noise ratio(CNR) were compared for imaging of the infra-aortic arch,brachiocephalic trunk,subclavian artery(left/right),common carotid artery(left/right),internal carotid artery(left/right),and external carotid artery(left/right). Characteristics of the time-signal-intensity(T-S-I) curves were also analyzed at the two injection rates. All studies were performed successfully,without any complications. There was good image quality with both gadobutrol injection rates of 1.5 mL/s and 2.0 mL/s,and subjective scores for image quality,SNR and CNR were not significantly different between the two rates(P 0.05). The time-to-peak(TTP) from the hand dorsal vein injection site to the carotid artery ranged from 16.0 s to 27.1 s(mean 21.7 s ±3.4 s) in the 6 subjects,and was also not significantly different between the two drug injection rates(P 0.05). We conclude that dynamic CEM RA examination of the supra-aortic arch with gadobutrol injection at a rate of 1.5 mL/s was feasible,and satisfactorily reflected vascular shape and dynamic blood flow information. 相似文献