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1.
一种分子连接性指数和维纳指数以及碳原子个数与链烷烃的标准生成焓,标准生成熵具有良好的性质相关性,相关系数大于0.99.  相似文献   

2.
杨尚梅  吴启勋 《科技信息》2007,(32):78-78,140
一种分子连接性指数和维纳指数以及碳原子个数与链烷烃的标准生成焓,标准生成熵具有良好的性质相关性,相关系数大于0.99。  相似文献   

3.
基于核磁共振现象定义了一个新的拓扑指数1R,研究了链烷烃的标准熵与1R及碳原子得到数N的相关性.对比发现,157个链烷烃标准熵的计算值与实验值非常吻合,分析得到的方程可用于链烷烃标准熵的估算与预测.  相似文献   

4.
用M,M,P,q,n等分子参数表征链烷烃的分子大小、取代参量和相邻取代基的相互作用,并以其为独立变量,通过回归方法建立模型预测链烷烃的某些物理化学性质,85种链烷烃的沸点、标准生成焓、标准熵、标准自由能以及1-9个碳原子链烷烃的气化焓、摩尔体积、摩尔折光度的预测表明该模型的原理简单、方法实用.为预测链烷烃物理化学性质提供了可靠的手段。  相似文献   

5.
用边邻接指数预测链烷烃的热力学性质   总被引:4,自引:0,他引:4       下载免费PDF全文
用分子图理论和边价 (δei)建构新的连接性指数 (mE) ,籍以描述分子的大小及分支情况 .其中 ,0 E、1 E和碳原子的最大支化度 (δmax)或路径数P3 与 85种链烷烃的标准生成焓 (ΔfHθm)、标准熵 (Sθm)、标准生成自由能 (ΔfGθm)具有良好的相关性 :-ΔfHθm =5 1.12 0 7+2 .0 6 0 2 0 E+38.0 746 1 E+8.5 116δmax,R =0 .9979,Sθm =179.4143+35 .18840 E +2 8.0 3981 E - 1.0 0 3 4δmax,R =0 .9988,ΔfGθm =- 42 .4941+2 .5 330 0 E +9.38131 E +2 .12 5 9P3,R =0 .993 6 .  相似文献   

6.
从邻接矩阵和距离矩阵,维纳指数(W),分子的路径数(Pn)或1阶分子连接性指数(1X)的最优子集出发,结合矩阵的运算方法,定义了一个新的拓扑指数ZX来研究饱和链烷烃的沸点(Tb),标准生成焓(△fH0m),标准生成熵(S0m),标准吉布斯自由能(△fG0m),具有良好的性质相关性,相关系数(r)均大于0.99.  相似文献   

7.
将函数内逆P-集合理论引入QSPR研究中,利用函数内逆P-集合的动态特征筛选预测链烷烃标准生成焓的属性参数, 运用函数内逆P-集合的规律特征给出不同类型的预测链烷烃标准生成焓的规律函数。成功地预测了41种链烷烃的标准生成焓。结果表明,属性参数与链烷烃的标准生成焓高度相关,复相关系数达到或超过0.998。  相似文献   

8.
以文献报道的部分正烷烃、正烯烃、正炔烃、正烷基苯、正烷硫醇298K下气态化合物标准生成焓、标准生成自由能、标准熵的数据为基础,通过计算机进行回归分析,得到了这些有机物的标准生成焓,标准生成自由能,标准熵均与碳原子数(n)呈良好的线性关系.即据这些关系式分别计算了一系列直链有机物的,其结果与文献值相吻合.  相似文献   

9.
从分子的距离矩阵出发,构建一种新的分子拓扑指数XZ;用此指数通过SPSS统计软件对95种链烷烃的标准生成焓进行一元线性回归,结果表明,指数XZ具有良好的结构选择性和性质相关性.  相似文献   

10.
本文利用距离邻接矩阵的增广矩阵方法建立了一种新的拓扑指数Q,用Q与链烷烃的理化性质进行关联,效果良好.其计算方法简便,准确性较高,  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.
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   

13.
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   

14.
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   

15.
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   

16.
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   

17.
For molecular systems,the quantum-mechanical treatment of their responses to static electromagnetic fields usually employs a scalar-potential treatment of the electric field and a vector-potential treatment of the magnetic field.Although the potential for each field separately is associated with the choice of an(unphysical)origin,the precise choice of the origin for the electrostatic field has little consequences for the results.This is different for the  相似文献   

18.
Franck-Condon factors bridge the gap between theoretical modeling and experimental observations for molecular electronic spectroscopy and electron transfer.Under the displaced harmonic oscillator approximation,multidimensional Franck-Condon factors are decomposed into a product of many one-dimensional(1D)Franck-Condon(FC)factors,and each 1D-FC factor is associated with one Huang-Rhys factor that determines the leading contribution of  相似文献   

19.
<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   

20.
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