Journal De Physique Ii最新文献_第10页

Smectic Compressibility of Polymer-Containing Lyotropic Lamellar Phases: An Experimental Tool to Study the Thermodynamics of Polymer Confinement 含溶致层状相聚合物的近晶可压缩性:研究聚合物约束热力学的实验工具

Journal De Physique Ii Pub Date : 1997-03-01 DOI: 10.1051/JP2:1997139

C. Ligoure, G. Bouglet, G. Porte, O. Diat

{"title":"Smectic Compressibility of Polymer-Containing Lyotropic Lamellar Phases: An Experimental Tool to Study the Thermodynamics of Polymer Confinement","authors":"C. Ligoure, G. Bouglet, G. Porte, O. Diat","doi":"10.1051/JP2:1997139","DOIUrl":"https://doi.org/10.1051/JP2:1997139","url":null,"abstract":"Nous avons decouvert un systeme mixte constitue d'une phase smectique de membranes fluides (melange en proportion appropriee d'hexanol et de chlorure de cethylpyridinium), dans une solution aqueuse d'un polymere hydrosoluble neutre non adsorbant de tres grande masse moleculaire : le polyvinylpyrolidonne. Ce systeme permet de realiser experimentalement les diverses situations de confinement d'une solution de macromolecules entre deux plans. La presence du polymere entre les membranes induit une interaction effective entre membranes qui depend du regime de confinement. Nous calculons la contribution a la compressibilite smectique de cette interaction effective dans chacun des quatres regimes attendus ; c'est une fonction non monotone de la concentration en polymere dans le solvant. Cette grandeur thermodynamique est particulierement interessante car elle est mesurable par diffusion de rayonnement aux petits angles (X ou neutrons). Notre modele permet d'interpreter quantitativement la separation de phase lamellaire/lamellaire observee par addition progressive de sel pour une composition particuliere du systeme.","PeriodicalId":14774,"journal":{"name":"Journal De Physique Ii","volume":"55 1","pages":"473-491"},"PeriodicalIF":0.0,"publicationDate":"1997-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91332805","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: 23

Layer compression modulus of electrostatically stabilized lyotropic lamellar phases revisited : Application to the quantitative analysis of a polymer induced critical SmA-SmA phase separation 重新探讨了静电稳定溶致层状相的层压缩模量:应用于聚合物诱导的SmA-SmA临界相分离的定量分析

Journal De Physique Ii Pub Date : 1997-03-01 DOI: 10.1051/JP2:1997140

L. Porcar, C. Ligoure, J. Marignan

引用次数: 11

Inhomogeneous Flows of Complex Fluids: Mechanical Instability Versus Non-Equilibrium Phase Transition 复杂流体的非均匀流动:机械不稳定性与非平衡相变

Journal De Physique Ii Pub Date : 1997-03-01 DOI: 10.1051/JP2:1997138

G. Porte, J. Berret, J. Harden

引用次数: 86

Solid-Like Director Reorientation in Sheared Hexagonal Lyotropic Liquid Crystals as Studied by Nuclear Maginetic Resonance 核磁共振研究剪切六方溶致液晶的类固体导向重定向

Journal De Physique Ii Pub Date : 1997-03-01 DOI: 10.1051/JP2:1997135

S. Müller, P. Fischer, C. Schmidt

引用次数: 14

Random Copolymer: Gaussian Variational Approach

Journal De Physique Ii Pub Date : 1997-02-19 DOI: 10.1051/jp2:1997134

A. Moskalenko, Yu. A. Kuznetsov, Kenneth A. Dawson

引用次数: 4

Scaling behavior in economics: II. Modeling of company growth 经济学中的规模行为:2。公司成长模型

Journal De Physique Ii Pub Date : 1997-02-10 DOI: 10.1051/jp1:1997181

S. Buldyrev, L. A. Amaral, L. A. Amaral, S. Havlin, S. Havlin, H. Leschhorn, P. Maass, M. Salinger, H. Stanley, M. H. Stanley

{"title":"Scaling behavior in economics: II. Modeling of company growth","authors":"S. Buldyrev, L. A. Amaral, L. A. Amaral, S. Havlin, S. Havlin, H. Leschhorn, P. Maass, M. Salinger, H. Stanley, M. H. Stanley","doi":"10.1051/jp1:1997181","DOIUrl":"https://doi.org/10.1051/jp1:1997181","url":null,"abstract":"In the preceding paper we presented empirical results describing the growth of publicly-traded United States manufacturing firms within the years 1974--1993. Our results suggest that the data can be described by a scaling approach. Here, we propose models that may lead to some insight into these phenomena. First, we study a model in which the growth rate of a company is affected by a tendency to retain an ``optimal'' size. That model leads to an exponential distribution of the logarithm of the growth rate in agreement with the empirical results. Then, we study a hierarchical tree-like model of a company that enables us to relate the two parameters of the model to the exponent $beta$, which describes the dependence of the standard deviation of the distribution of growth rates on size. We find that $beta = -ln Pi / ln z$, where $z$ defines the mean branching ratio of the hierarchical tree and $Pi$ is the probability that the lower levels follow the policy of higher levels in the hierarchy. We also study the distribution of growth rates of this hierarchical model. We find that the distribution is consistent with the exponential form found empirically.","PeriodicalId":14774,"journal":{"name":"Journal De Physique Ii","volume":"9 1","pages":"635-650"},"PeriodicalIF":0.0,"publicationDate":"1997-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74488895","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: 118

Analytical Weak-Segregation Theory of Bicontinuous Phases in Diblock Copolymers 双嵌段共聚物中双连续相的分析弱偏析理论

Journal De Physique Ii Pub Date : 1997-02-01 DOI: 10.1051/JP2:1997122

S. Milner, P. Olmsted

引用次数: 20

Undulating Charged Fluid Membranes and their Bending Constants 波动带电流体膜及其弯曲常数

Journal De Physique Ii Pub Date : 1997-02-01 DOI: 10.1051/JP2:1997121

A. Fogden, J. Daicic, A. Kidane

{"title":"Undulating Charged Fluid Membranes and their Bending Constants","authors":"A. Fogden, J. Daicic, A. Kidane","doi":"10.1051/JP2:1997121","DOIUrl":"https://doi.org/10.1051/JP2:1997121","url":null,"abstract":"We consider harmonically undulating ionic surfactant membranes, calculating a general expression for the bending modulus valid for all salt and surfactant concentrations, and surface charge densities. This is achieved through a perturbative expansion of the mean-field electrostatic potential and free energy about a planar reference state, consisting of two parallel planar membranes with intervening salt solution. For a given choice of undulation mode, the result for the bending modulus is seen to be generally the same as that obtained from considerations of membranes deformed into a cylindrical geometry. Thus, we show that the bending modulus is independent of global aggregate geometry, at a general system composition. Specializing to the limit of excess added salt (equivalent to a single undulating membrane in contact with bulk electrolyte), we are able to extend the free energy calculation to fourth order in undulation amplitude, and derive the bending constants of the curvature expansion to this order. These have been suggested previously to be of importance in explaining the stability of bicontinuous crystalline and disordered phases, and the formation of passages in lamellar phases. We also discuss the breakdown of the curvature description at shorter wavelengths.","PeriodicalId":14774,"journal":{"name":"Journal De Physique Ii","volume":"11 1","pages":"229-248"},"PeriodicalIF":0.0,"publicationDate":"1997-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83528201","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: 11

Conformational and Orientational Characteristics of Chain Molecules Placed in Nematic Fields. Part II 链分子在向列场中的构象和取向特性。第二部分

Journal De Physique Ii Pub Date : 1997-02-01 DOI: 10.1051/JP2:1997127

Yuji Sasanuma

{"title":"Conformational and Orientational Characteristics of Chain Molecules Placed in Nematic Fields. Part II","authors":"Yuji Sasanuma","doi":"10.1051/JP2:1997127","DOIUrl":"https://doi.org/10.1051/JP2:1997127","url":null,"abstract":"Deuterium NMR quadrupolar splittings and 2 H - 2 H dipolar couplings observed from perdeuterated 1,6-dimethoxyhexane (CD 3 O(CD 2 ) 6 OCD 3 ) dissolved in a liquid crystal 4'-methoxybenzylidene-4-η-butylaniline (MBBA) were analyzed using the single-ordering-matrix (SOM) and the Photinos-Samulski-Toriumi (P-S-T) models. Within the framework of the rotational isomeric state approximation, intramolecular interactions up to the third-order (between atoms and groups separated by five bonds) were considered. The geometrical parameters and intramolecular interaction energies determined from ab initio molecular orbital calculations were employed. The two simulation models yielded fair agreement between theory and experiment, but were found to give quite different images of the solute chain: (the SOM model), the solute becomes rigid and extended to conform itself to the nematic field; (the P-S-T model), the solute has almost the same degree of flexibility as in the free state, but populations of the anisotropic conformers are selectively enhanced. To reveal the true conformational characteristics of chain molecules in nematic fields, experimental techniques to enable direct and quantitative measurements of the bond conformations are necessary.","PeriodicalId":14774,"journal":{"name":"Journal De Physique Ii","volume":"21 1 1","pages":"305-317"},"PeriodicalIF":0.0,"publicationDate":"1997-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86129479","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

Nanorheology of adsorbed diblock copolymer layers 吸附二嵌段共聚物层的纳米流变性

Journal De Physique Ii Pub Date : 1997-02-01 DOI: 10.1051/JP2:1997124

Erica Pelletier, G. F. Belder, G. Hadziioannou, A. Subbotin

引用次数: 10