Computers & chemistry最新文献_第10页

A numerical modelling of voltammetric reduction of substituted iodobenzenes reaction series. A relationship between reductions in the consecutive-mode multistep system and a multicomponent system. Determination of the potential variation of the elementary charge transfer coefficient 取代碘苯系列反应伏安还原的数值模拟。连续模式多步系统和多组分系统的降阶之间的关系。基本电荷传递系数电位变化的测定

Computers & chemistry Pub Date : 2001-11-01 DOI: 10.1016/S0097-8485(00)00114-5

Przemysław Sanecki

{"title":"A numerical modelling of voltammetric reduction of substituted iodobenzenes reaction series. A relationship between reductions in the consecutive-mode multistep system and a multicomponent system. Determination of the potential variation of the elementary charge transfer coefficient","authors":"Przemysław Sanecki","doi":"10.1016/S0097-8485(00)00114-5","DOIUrl":"10.1016/S0097-8485(00)00114-5","url":null,"abstract":"<div>The cyclic voltammetry reduction process of the reaction series of substituted iodobenzenes X–C6H4–I where X=H, p-Cl, p-Br, p-I, p-CH3, m-CF3 was investigated in 0.3 M TBAP in DMF. A numerical model of the process consistent with the ECE mechanism of mono-iodobenzenes reduction and consecutive ECE–ECE reduction of p-diiodobenzene was applied. On the basis of αi vs. Ep,i dependence, the value of ∂αi/∂E was found to be 0.37±0.07 for first electron transfer (Eq. (10). The ECE–ECE system seems to be an another example of elementary α kinetic discrimination between two identical two-electron processes analogous to that described in a previous paper (Sanecki, P., Kaczmarski, K. (1999). J. Electroanal. Chem. 471, 14 and erratum to it (2001)). A method of simultaneous treatment of the substrate and all electroactive intermediates, i.e. the transformation of any experimental consecutive CV reduction curves (e.g. ECE or ECE–ECE) into curves corresponding to reduction of the multi-component systems is presented and discussed.</div>","PeriodicalId":79331,"journal":{"name":"Computers & chemistry","volume":"25 6","pages":"Pages 521-539"},"PeriodicalIF":0.0,"publicationDate":"2001-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0097-8485(00)00114-5","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76155715","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 15

Multi-isotopic Modelling of Mass Spectra: A Procedure for Verification of the Fragmentation Hypothesis for the Organometallic and Coordination Compounds 质谱的多同位素模拟:金属有机化合物和配位化合物碎片化假说的验证程序

Computers & chemistry Pub Date : 2001-11-01 DOI: 10.1016/S0097-8485(01)00067-5

Andrzej J. Goraczko, J. Szymura

引用次数: 2

Erratum to “High order spatial discretisations in electrochemical digital simulation. 2. Combination with the extrapolation algorithm” “电化学数字模拟中的高阶空间离散”的勘误。2. 结合外推算法

Computers & chemistry Pub Date : 2001-09-01 DOI: 10.1016/S0097-8485(01)00108-5

J. Strutwolf , D. Britz

引用次数: 0

Pressure dependence of ionic polarizabilities in crystals 晶体中离子极化率的压力依赖性

Computers & chemistry Pub Date : 2001-09-01 DOI: 10.1016/S0097-8485(00)00107-8

Maria Carolina Monard , Jorge A.O. Bruno , Joaquina Faour , Alicia Batana

引用次数: 7

Three-dimensional quantitative structure–activity relationship for several bioactive peptides searched by a convex hull–comparative molecular field analysis approach 用凸壳-比较分子场分析方法搜索几种生物活性肽的三维定量构效关系

Computers & chemistry Pub Date : 2001-09-01 DOI: 10.1016/S0097-8485(00)00113-3

Thy-Hou Lin, Jia-Jiunn Lin

{"title":"Three-dimensional quantitative structure–activity relationship for several bioactive peptides searched by a convex hull–comparative molecular field analysis approach","authors":"Thy-Hou Lin, Jia-Jiunn Lin","doi":"10.1016/S0097-8485(00)00113-3","DOIUrl":"10.1016/S0097-8485(00)00113-3","url":null,"abstract":"<div>Three-dimensional (3D) convex hulls are computed for theoretically generated structures of a group of 18 bioactive tachykinin peptides. The number of peptides treated as a training set is 14, whereas that treated as a test set is four. The frequency of atoms of the same atomic type lying at the vertices of all the hulls computed for all the structures in a structural set is counted. Vertex atoms with non-zero frequency counted are collected together as a set of commonly exposed groups. These commonly exposed atoms are then treated as a set of correspondences for aligning all the other 13 structures in a structural set against a common template, which is the structure of the most potent peptide in the set using the FIT module of the sybyl 6.6 program. Each aligned structural set is then analyzed by the comparative molecular field analysis (CoMFA) module using the C.3 probe having a charge of +1.0. The corresponding cross-validated r2 values range from −0.99 to 0.57 for a number of 73 structural sets studied. The comparative molecular similarity indices analysis (CoMSIA) module within the sybyl 6.6 package is also used to analyze some of these aligned structural sets. Although the CoMSIA results are in accord with those of CoMFA, it is also found that the CoMFA results of several structural sets can be improved somewhat for conformations of the structures in the sets that are adjusted by constraint energy minimization and then constraint molecular dynamics simulation runs using distance constraints derived from some commonly exposed groups determined for them. This result further implies that the convex hull–CoMFA is a feasible approach to screen the bioactive conformations for molecules of this class.</div>","PeriodicalId":79331,"journal":{"name":"Computers & chemistry","volume":"25 5","pages":"Pages 489-498"},"PeriodicalIF":0.0,"publicationDate":"2001-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0097-8485(00)00113-3","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86670772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Resolution by polarographic techniques of the ternary mixture of captan, captafol and folpet by using PLS calibration and artificial neuronal networks 利用PLS校准和人工神经网络，用极谱技术对队长、队长醇和队长醇的三元混合物进行分辨

Computers & chemistry Pub Date : 2001-09-01 DOI: 10.1016/S0097-8485(00)00109-1

A. Guiberteau , T. Galeano , N. Mora , F. Salinas , J.M. Ortı́z , J.C. Viré

{"title":"Resolution by polarographic techniques of the ternary mixture of captan, captafol and folpet by using PLS calibration and artificial neuronal networks","authors":"A. Guiberteau , T. Galeano , N. Mora , F. Salinas , J.M. Ortı́z , J.C. Viré","doi":"10.1016/S0097-8485(00)00109-1","DOIUrl":"10.1016/S0097-8485(00)00109-1","url":null,"abstract":"<div>The simultaneous polarographic determination of the ternary mixture of captan-captafol and folpet is studied. The polarographic signals of these compounds in their mixture show a high overlapping. For this reason different chemometric methods such as PLS, PCR and artificial neuronal network (ANN) have been utilized for the simultaneous determination of these compounds in mixtures. The calibration model is built from solutions containing river water of known pesticide concentrations and the signals obtained by Sampled DC and DPP (differential pulse polarography) have been used. The analysis of both synthetic and real samples (river water) has been carried out by PLS with satisfactory results in most cases. It is possible to determine 0.25 ppm of each pesticide in river water samples after a preconcentration step by extraction into diethyl ether. ANN has also been applied to improve the results obtained by the PLS tool when the sampled DC current is recorded or when liquid–solid extraction with C18 cartridges is performed.</div>","PeriodicalId":79331,"journal":{"name":"Computers & chemistry","volume":"25 5","pages":"Pages 459-473"},"PeriodicalIF":0.0,"publicationDate":"2001-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/S0097-8485(00)00109-1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72982424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 13

Experimental study of precipitating systems; computerised analysis of the optical transmittance and associated noise 降水系统的实验研究;光学透射率和相关噪声的计算机化分析

Computers & chemistry Pub Date : 2001-09-01 DOI: 10.1016/S0097-8485(00)00106-6

J.A. Poce-Fatou, R. Alcántara, J.J. Gallardo, J. Martı́n

引用次数: 1

A new numerical procedure to determine the VLE curve 一种确定VLE曲线的新数值方法

Computers & chemistry Pub Date : 2001-09-01 DOI: 10.1016/S0097-8485(00)00112-1

W. Okrasiński , M.I. Parra , F. Cuadros

引用次数: 6

Prediction of enthalpy of alkanes by the use of radial basis function neural networks 用径向基函数神经网络预测烷烃的焓

Computers & chemistry Pub Date : 2001-09-01 DOI: 10.1016/S0097-8485(00)00110-8

Xiaojun Yao , Xiaoyun Zhang , Ruisheng Zhang , Mancang Liu , Zhide Hu , Botao Fan

引用次数: 36

High order spatial discretisations in electrochemical digital simulation. 2. Combination with the extrapolation algorithm 电化学数字仿真中的高阶空间离散。2. 结合外推算法

Computers & chemistry Pub Date : 2001-09-01 DOI: 10.1016/S0097-8485(01)00082-1

J. Strutwolf , D. Britz

引用次数: 5