溴化[2—(5—己基—1,3—二氧环己烷——2—基)乙基]三乙基铵的合成<英>     

袁先友 《零陵学院学报》1992,(3)

以1—溴己烷,丙二酸二乙酯和丙烯醛为原料,经五步反应首次合成了溴化[2—(5—己基—1,3—二氧环己烧—2—基)乙基]三乙基铵(h).  相似文献   

主观化标记词“好端端”     

张治 《云南师范大学学报(教育科学版)》2008,(6):57-64

状态形容词“好端端”和其他的ABB式状态词不同：由于它在词汇化过程中,词缀“端端”的“语义滞留”使它不论作何种句法成分,都要求与含有“出乎意料”语义的“对比句”同现,我们称之为“好端端”的“反预期语义标记功能”。“好端端”在共时平面上呈现出的句法位置之间存在着历时平面的语法化过程,从先到后：作谓语《作状语》作定语,各个句法位置出现的使用频率从左至右依次递增。另外,“好端端”与数量短语搭配时的所处位置前后的不同,也会对表达的主观性程度产生影响。  相似文献   

Structural Equation Modeling With Unknown Population Distributions: Ridge Generalized Least Squares     

Ke-Hai Yuan  Wai Chan 《Structural equation modeling》2016,23(2):163-179

This article proposes 2 classes of ridge generalized least squares (GLS) procedures for structural equation modeling (SEM) with unknown population distributions. The weight matrix for the first class of ridge GLS is obtained by combining the sample fourth-order moment matrix with the identity matrix. The weight matrix for the second class is obtained by combining the sample fourth-order moment matrix with its diagonal matrix. Empirical results indicate that, with data from an unknown population distribution, parameter estimates by ridge GLS can be much more accurate than those by either GLS or normal-distribution-based maximum likelihood; and standard errors of the parameter estimates also become more accurate in predicting the empirical ones. Rescaled and adjusted statistics are proposed for overall model evaluation, and they also perform much better than the default statistic following from the GLS method. The use of the ridge GLS procedures is illustrated with a real data set.  相似文献   

彝族服饰图纹类型、艺术特点及美学价值   总被引：3，自引：0，他引：3  

范例 《云南师范大学学报(哲学社会科学版)》2004,36(2):31-35

从图纹的类型、艺术特点和美学价值上 ,探讨了彝族服饰图纹的文化品位。按属性把彝族的服饰图纹归纳为 :几何型图纹 ,图腾式图纹 ,花卉、鱼虫图纹和自然景物图纹四种类型。并从多元化整体美 ,以自然美作基调 ,崇拜性思想的反映 ,融入外族及现代艺术成分四要素上对彝族服饰图纹的艺术特点及艺术价值进行了剖析  相似文献   

互联网时代浙江中小企业电子商务应用研究   总被引：2，自引：0，他引：2  

钱栋霖 《丽水学院学报》2008,30(6):11-15

中小企业是浙江经济的重要组成部分,也是开展企业电子商务的重要力量。随着网络的普及,中小企业应用电子商务成为必然趋势。开展电子商务可以为中小企业弥补自身缺陷,提升竞争优势,带来新的发展机遇。采用B2B商业模式、加入BAB电子商务交易市场、实现电子商务与ERP系统的集成是浙江中小企业开展电子商务的重要途径。  相似文献   

卤代硅烷的醇解与应用   总被引：1，自引：0，他引：1  

陈忠云 《邵阳学院学报(社会科学版)》1997,(2)

本文着重讨论了卤代硅烷醇解反应的机理、条件与应用.  相似文献   

新世纪普通高等学校期待新型体育教师     

张良祥  杨万林 《黑龙江高教研究》2004,(3):43-44

随着体育课程改革的深入和信息社会的发展，新世纪普通高等学校需要新型体育教师。师资队伍建设应侧重于更新观念、加强继续教育、强化现代信息能力等。  相似文献   

Polyethylenimine-cyclodextrin-tegafur conjugate shows anti-cancer activity and a potential for gene delivery     

Hu QD  Fan H  Lou WJ  Wang QQ  Tang GP 《Journal of Zhejiang University. Science. B》2011,12(9):720-729

Polyethylenimine-cyclodextrin-tegafur (PEI-CyD-tegafur) conjugate was synthesized as a novel multifunctional prodrug of tegafur for co-delivery of chemotherapeutic agent tegafur and enhanced green fluorescent protein (EGFP) reporter plasmid DNA. Conjugation of tegafur to PEI-CyD via chemical linkage was characterized by ¹H NMR spectrometry and ultraviolet (UV) spectrometry. PEI-CyD-tegafur was able to condense plasmid DNA into complexes of around 150 nm with positive charge at the N/P ratio of 25, in accordance with electron microscopy observation of compact and monodisperse nanoparticles. The results of in vitro experiments showed enhanced cytotoxicity and considerable transfection efficiency in B16F10 cell line. Therefore, PEI-CyD-tegafur may have great potential as a co-delivery system with anti-cancer activity and potential for gene delivery.  相似文献   

Mixed G<Emphasis Type="Italic">l</Emphasis><Subscript>2</Subscript>/G<Emphasis Type="Italic">H</Emphasis><Subscript>2</Subscript> multi-channel multi-objective control synthesis for discrete time systems     

Wen-jun?YanEmail author  Sen-lin?Zhang 《浙江大学学报(A卷英文版)》2004,5(7):827-834

This paper proposes a new approach for multi-objective robust control. The approach extends the standard generalizedl ₂ (Gl ₂) and generalizedH ₂ (GH ₂) conditions to a set of new linear matrix inequality (LMI) constraints based on a new stability condition. A technique for variable parameterization is introduced to the multi-objective control problem to preserve the linearity of the synthesis variables. Consequently, the multi-channel multi-objective mixed Gl ₂/GH ₂ control problem can be solved less conservatively using computationally tractable algorithms developed in the paper. Project supported by the National Natural Science Foundation of China (No. 60374028), and the Scientific Research Foundation for Returned Overseas Chinese Scholars, Ministry of Education (No. [2004]176)  相似文献   

清末白话文的渐兴与“民智意识”的强化     

董丛林 《天津师范大学学报(社会科学版)》2003,23(3):37-41

由“言文分离”而影响民智开通的弊端在晚清明显地暴露出来,不同政派所属的有识见者,为在这方面除弊兴利多有所尝试,特别是从资产阶级维新、改良派到革命派所主导的早期白话文运动,对于从较高层次上开通民智所发挥的作用尤其显著。而民众在时势条件的促迫下,也有积极的呼应。总的看来,清末白话文的渐兴与民智意识的强化密切关联,这也为民国初年在一个更高层次上开展的白话文运动作了铺垫。  相似文献