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1.
阐述了1,2-二取代二茂铁类分子的螺旋结构的来源,指明其结构与旋光方向的关系,然后详细地分析了几个有代表性的1,2-二取代二茂铁类分子的螺旋结构与旋光方向,结果表明:二价铁离子与两个取代基的相互作用力以及两个取代基之间的相互作用力共同决定着指定构型的二茂铁会形成哪种螺旋,从而呈现一定的旋光方向。  相似文献   

2.
先从理论上阐述了环氧乙烷类分子的螺旋结构与旋光方向的关系,然后详细地分析了各种有代表性的这类分子的两间的关系。结果表明这类分子的构型与其旋光方向有着密切的联系。从分子的构型可以推断其旋光方向;反过来,从分子的旋光方向亦可推断出它们的构型。  相似文献   

3.
为了扩展我们的理论成果,现选取手性旋光的4-取代[2.2]二聚二甲苯类化合物{其CA命名为5-取代三环[8.2.2.2^4.7]十六碳-4,6,10,12,13,15-六烯}作为螺旋结构与旋光方向研究的第六个序列.通过构象分析和依据螺旋判定规则,指定了模型分子的旋光方向,然后从献中找出了21个这类衍生物和它们的旋光值.比较结果显示,R-构型4-取代[2.2]二聚二甲苯类衍生物净值螺旋性为负,所显示的旋光方向也为负;同理,S-构型类净值螺旋性为正,所显示的旋光方向也为正,从而验证了螺旋理论的正确性。  相似文献   

4.
手性化合物的螺旋结构与其光学活性的关系,是有机化学家长期关注的问题.本文详细地分析了2-取代四氢吡咯类化合物的结构特征,并建立起结构与旋光方向的联系,从中揭示出物质结构与旋光方向的一般规律.  相似文献   

5.
手性分子的螺旋结构与其光学活性的关系,是有机化学家长期关注的问题.本文详细地分析了1,2-二取代环已烷类化合物的结构特征,并建立起结构与旋光方向的联系,从中揭示出物质结构与旋光方向的一般规律.  相似文献   

6.
为了扩展我们的理论成果 ,现选取手性旋光的 4 -取代 [2 .2 ]二聚二甲苯类化合物 {其 CA命名为 5 -取代三环 [8.2 .2 .2 4 ,7]十六碳 - 4 ,6 ,10 ,12 ,13,15 -六烯 }作为螺旋结构与旋光方向研究的第六个序列 .通过构象分析和依据螺旋判定规则 ,指定了模型分子的旋光方向 ,然后从文献中找出了 2 1个这类衍生物和它们的旋光值 .比较结果显示 ,R-构型 4 -取代 [2 .2 ]二聚二甲苯类衍生物净值螺旋性为负 ,所显示的旋光方向也为负 ;同理 ,S-构型类净值螺旋性为正 ,所显示的旋光方向也为正 ,从而验证了螺旋理论的正确性  相似文献   

7.
手性分子的螺旋结构与其光学活性的关系,是有机化学家长期关注的问题,本文详细地分析了1,2-二取代环己烷类化合物的结构特征,并建立起结构与旋光方向的联系,从中揭示出质结构与旋光方向的一般规律。  相似文献   

8.
手性化合物的螺旋结构与其光学活性的关系,是有机化学家长期关注的问题,本文详细地分析了2-取代四氢吡咯类化合物的结构特征,并建立起结构与旋光方向的联系,从中揭示出物质结构与旋光方向的一般规律。  相似文献   

9.
本文将旋光性的电磁理论与生物化学中实测的六螺苯和蛋白质的旋光度进行了对比,结果相符良好,阐明了基于螺旋结构模型的旋光性理论的正确性。  相似文献   

10.
用量子力学与分子力学组合的ONIOM方法, 考察布洛芬(Ibu)分子限域在螺旋手性单壁碳纳米管(SWCNT)内的手性转变机理. 结果表明: 螺旋手性单壁碳纳米管的直径越小, 限域在其孔道内的布洛芬分子形变越明显; 布洛芬分子在SWCNT(6,4)和SWCNT(7,4)内的旋光异构只有一个反应通道, 在SWCNT(8,5)内的旋光异构有两个反应通道; 布洛芬分子限域在SWCNT(6,4),SWCNT(7,4)和SWCNT(8,5)内时, 旋光异构反应决速步骤的内禀能垒分别为24795,27383,29224 kJ/mol, 总包能垒分别为27896,29191,32588 kJ/mol. 可见S-Ibu的旋光异构易在较小孔径的螺旋手性SWCNT内实现, SWCNT(6,4)可以作为布洛芬分子旋光异构的纳米反应器.  相似文献   

11.
Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.  相似文献   

12.
何延凌 《科技信息》2008,(4):258-258
Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women's language from these perspectives: pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women's language, more attention should be paid to language use in social context. What's more, the linguistic phenomena in a speaking community can be understood more thoroughly.  相似文献   

13.
理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。  相似文献   

14.
As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.  相似文献   

15.
正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-  相似文献   

16.
We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-  相似文献   

17.
正The electronic and nuclear(structural/vibrational)response of 1D-3D nanoscale systems to electric fields gives rise to a host of optical,mechanical,spectral,etc.properties that are of high theoretical and applied interest.Due to the computational difficulty of treating such large systems it is convenient to model them as infinite and periodic(at least,in first approximation).The fundamental theoretical/computational problem in doing so is that  相似文献   

18.
<正>"The Journal of Shanghai Normal University:Mathematics"is published by Shanghai Normal University as regular issues of The Journal of Shanghai Normal University each year from 2014 in English.The editors-in-chief of the issues are professors Yuhao Cong and Maoan Han.The Journal of Shanghai Normal University was started in 1958 with  相似文献   

19.
20.
<正>"Journal of Jilin University(Science Edition)"is a comprehensive academic journal in the fields of science sponsored by Jilin University and administrated by the Ministry of Education of the Peoples Republic of China.The journal started publication in 1955.The original name at starting publication was"Journal of Natural Science of Northeast People University",which was changed into"Acta Scientiarum Naturalium Universitatis Jilinensis"in 1958 owing to the name change of the university.The present journal name has  相似文献   

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