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201.
文章通过简要介绍纳米技术的重要意义指出对纳米技术领域进行监测的必要性,并对其进行了详细的实证监测分析评估,最后根据纳米技术的监测结果对发展我国纳米技术提出了政策建议。  相似文献   
202.
陈小卉  胡平  周奕岑 《情报学报》2020,39(4):450-458
社会化问答社区的出现改变了原有的问答模式并拓展了知识获取的途径。回答者作为知识的主要贡献者,是促进问答社区内知识传递的核心要素。现有关于问答社区用户的研究普遍以用户的属性数据为依据,较少考虑使用个体连接所形成的关系数据进行分析。本文以中文问答社区"知乎"为研究对象,爬取了"流行音乐"和"英语学习"两个话题下的大规模数据,通过构建回答者关注关系网络,定义和量化直接连接和间接连接两类同伴关系,使用网络自回归模型探究同伴效应对知识贡献行为的影响。研究发现,回答者的知识贡献行为会受到直接和间接连接同伴效应的正向影响,但是间接连接同伴效应会随着回答者网络密度的增加而逐渐减弱甚至消失,聚类系数对回答者的知识贡献行为有负向影响。  相似文献   
203.
朱文藻编著的《葆醇堂藏书录》采用"经、艺、史、志、子、集、类、说"八分法,试图打破四部分类框架。他整合小类设立艺部,把志部、类部、说部提升为一级类目,调整部分二、三级类目的划分、名称和顺序,对类书的性质和丛书的价值做出新认识,反映出以小学、金石学、舆地之学等为代表的乾嘉学术风貌。《葆醇堂藏书录》本着灵活变通的编目原则,力求突破四分法的桎梏,在图书分类上体现学术发展,是古籍目录辨章学术、考镜源流的积极尝试。  相似文献   
204.
数字资源采访实践工作中,图书馆面临着极大的版权风险。基于近年来图书馆数字资源相关版权纠纷统计分析,总结采购数字资源中的版权风险主要包括数字资源中含侵权作品、合同风险、服务风险等。图书馆应该对我国著作权相关法律中图书馆的版权例外保护条款和数字资源采访中的版权风险有充分而深入的认识,积极参与相关法律法规的完善,加强对数字资源供应商、资源合法性和合同的审查,强化数字资源服务中的技术保护措施、注意和告知义务,并制定图书馆版权管理办法。  相似文献   
205.
文章在对俄国形式主义的"陌生化"概念进行阐释的基础上尝试对其进行扩容,使其延伸至语言之外的领域,得以解释文学史嬗变更迭的原因.并且,本文对形式主义的思想局限略作评述,以论证对该概念的扩容根据及其合理性.  相似文献   
206.
Brix weight per stool (BW) of sugarcane is a complex trait, which is the final product of a combination of many components. Diallel cross experiments were conducted during a period of two years for BW and its five component traits, including stalk diameter (SD), stalk length (SL), stalk number (SN), stalk weight (SW), and brix scale (BS) of sugarcane. Phenotypic data of all the six traits were analyzed by mixed linear model and their phenotype variances were portioned into additive (A),dominance (D), additive×environment interaction (AE) and dominance×environment interaction (DE) effects, and the correlations of A, D, AE and DE effects between BW and its components were estimated. Conditional analysis was employed to investigate the contribution of the components traits to the variances of A, D, AE and DE effects of BW. It was observed that the heritabilities of BW were significantly attributed to A, D and DE by 23.9%, 30.9% and 28.5%, respectively. The variance of A effect for BW was significantly affected by SL, SN and BS by 25.3%, 93.7% and 17.4%, respectively. The variances of D and DE effects for BW were also significantly influenced by all the five components by 5.1%~85.5%. These determinants might be helpful in sugarcane breeding and provide valuable information for multiple-trait improvement of BW.  相似文献   
207.
The fruit shape is important quantitative trait closely related to the fruit quality. However, the genetic model of fruit shapes has not been proposed. Therefore, in the present study, analysis of genetic effects for fruit shape traits (fruit length and fruit perimeter) in sponge gourd was conducted by employing a developmental genetic model including fruit direct effects and maternal effects. Analysis approaches of unconditional and conditional variances were applied to evaluate the genetic behavior of fruit shape traits at economical and physiological maturation times. The results of variance analysis indicated that fruit length and fruit perimeter were simultaneously affected by fruit direct genetic effects and maternal effects. Fruit direct genetic effects were relatively more important for fruit shape traits at whole developmental period. The gene expression was most active at the economical maturation stage (1-12 d after flowering) for two shape traits, and the activation of gene was mostly due to direct dominance effects at physiological maturation stage (13-60 datter flowering). The coefficients due to different genetic effects, as well as the phenotypic correlation coefficients, varied significantly between fruit shape traits themselves at various maturation stages. The results showed that it was relatively easy to improve fruit shape traits for industrial purpose by carefully selecting the parents at economical maturation stage instead of that at physiological maturation stage.  相似文献   
208.
The objective of this study is to propose a more accurate and faster MTT 3-(4,5-dimethyl thiazol-2-yl)-2,5-diphenyl tetrazolium bromide colorimetric assay (MCA) for quantitative measurement of polypeptide bacteriocins in solutions with nisin as an example. After an initial incubation of nisin and indicator bacterium Micrococcus luteus NCIB 8166 in tubes, MTT was added for another incubation period. After that, nisin was quantified by estimating the number of viable bacteria based on measuring the amount of purple formazan produced by cleavage of yellow tetrazolium salt MTT. Then MCA was compared to a standard agar diffusion assay (ADA). The results suggested a high correlation coefficient (r2=0.975±0.004) between optical density (OD) and the inhibitory effect of nisin on a bacterial strain Micrococcus luteus NCIB 8166 at a range of 0.125~32 IU/ml. The MCA described in this study was very quick. Quantification of nisin took only 7~8 h and the detection limit was at the level of 0.125 IU/ml when compared to 12 IU/ml and 24~28 h for ADA. The MCA provides an accurate and rapid method for quantifi-cation of nisin in solutions and is expected to be used for quantification of other antimicrobial substances.  相似文献   
209.
210.
机电控制器类课程虚拟实验系统的研究与开发   总被引:2,自引:0,他引:2  
针对机电控制器类课程传统实验平台的缺点,提出了一种有效的解决方案:开发建立相应课程的虚拟实验系统.分别介绍了采用Proteus软件开发单片机课程虚拟实验系统和采用组态王软件开发PLC虚拟实验系统的研发思路、内容及实现方法,阐述了运用机电控制器类课程虚拟实验系统的教学效果及推广意义.  相似文献   
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