Pub Date : 1990-11-01DOI: 10.1051/JPHYS:0199000510220258100
J. Bulthuis, L. Plomp
The model of rotational diffusion in the presence of an orienting potential has been adapted to the case of an asymmetric top molecule in an orienting potential that is defined by two ordering parameters. It has been used to describe the relaxation by the quadrupolar mechanism of the deuterons in toluene, dissolved in «Phase V». No set of diffusion constants could be found, which simultaneously reproduce all spectral densities that were derived from the measured relaxation rates. Only very approximate agreement could be obtained with sets of diffusion constants in which two constants are of the same order of magnitude and the diffusion about the axis in the plane of the benzene ring and perpendicular to the axis of the methylgroup, is slower by an order of magnitude. The anisotropy in the viscosity of the solution has not explicitly been taken into account, but it has been indicated how this might be done. At this stage, therefore, no definitive conclusions can be drawn, but clearly the application of the rotational diffusion model in liquid crystalline solutions should be considered with care
{"title":"On the applicability of the rotational diffusion model in liquid crystalline solvents. A nuclear magnetic relaxation study of toluene","authors":"J. Bulthuis, L. Plomp","doi":"10.1051/JPHYS:0199000510220258100","DOIUrl":"https://doi.org/10.1051/JPHYS:0199000510220258100","url":null,"abstract":"The model of rotational diffusion in the presence of an orienting potential has been adapted to the case of an asymmetric top molecule in an orienting potential that is defined by two ordering parameters. It has been used to describe the relaxation by the quadrupolar mechanism of the deuterons in toluene, dissolved in «Phase V». No set of diffusion constants could be found, which simultaneously reproduce all spectral densities that were derived from the measured relaxation rates. Only very approximate agreement could be obtained with sets of diffusion constants in which two constants are of the same order of magnitude and the diffusion about the axis in the plane of the benzene ring and perpendicular to the axis of the methylgroup, is slower by an order of magnitude. The anisotropy in the viscosity of the solution has not explicitly been taken into account, but it has been indicated how this might be done. At this stage, therefore, no definitive conclusions can be drawn, but clearly the application of the rotational diffusion model in liquid crystalline solutions should be considered with care","PeriodicalId":14747,"journal":{"name":"Journal De Physique","volume":"1 1","pages":"2581-2593"},"PeriodicalIF":0.0,"publicationDate":"1990-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76162226","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}
Pub Date : 1990-11-01DOI: 10.1051/JPHYS:0199000510210238700
G. Kohring
Simulation results of a Willshaw type model for storing sparsely coded patterns are presented. It is suggested that random patterns can be stored in Willshaw type models by transforming them into a set of sparsely coded patterns and retrieving this set as a limit cycle. In this way, the number of steps needed to recall a pattern will be a function of the amount of information the pattern contains. A general algorithm for simulating neural networks with sparsely coded patterns is also discussed, and, on a fully connected network of N=36864 neurons (1.4×10 9 couplings), it is shown to achieve effective updaping speeds as high as 1.6×10 11 coupling evaluations per second on one Cray-YMP processor
{"title":"Performance enhancement of Willshaw type networks through the use of limit cycles","authors":"G. Kohring","doi":"10.1051/JPHYS:0199000510210238700","DOIUrl":"https://doi.org/10.1051/JPHYS:0199000510210238700","url":null,"abstract":"Simulation results of a Willshaw type model for storing sparsely coded patterns are presented. It is suggested that random patterns can be stored in Willshaw type models by transforming them into a set of sparsely coded patterns and retrieving this set as a limit cycle. In this way, the number of steps needed to recall a pattern will be a function of the amount of information the pattern contains. A general algorithm for simulating neural networks with sparsely coded patterns is also discussed, and, on a fully connected network of N=36864 neurons (1.4×10 9 couplings), it is shown to achieve effective updaping speeds as high as 1.6×10 11 coupling evaluations per second on one Cray-YMP processor","PeriodicalId":14747,"journal":{"name":"Journal De Physique","volume":"21 1","pages":"2387-2393"},"PeriodicalIF":0.0,"publicationDate":"1990-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87030053","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}
Pub Date : 1990-11-01DOI: 10.1051/JPHYS:0199000510220254300
O. Abillon, E. Perez
Nous avons mesure les forces entre deux surfaces de mica immergees dans une phase lamellaire gonflee a l'eau (CTAB/hexanol/eau salee). Les bicouches s'orientent parallelement aux surfaces de mica. Les courbes force-distance presentent des domaines ou l'eau est continument ejectee d'entre les lamelles, et des domaines ou le systeme saute rapidement a une autre distance en ejectant des lamelles. Nous avons etudie l'effet sur les forces d'un deplacement dans le diagramme de phases a periode spatiale constante et egalement le long de la ligne de dilution
{"title":"Swollen lamellar phases between two solid walls : undulation forces and generation of defects","authors":"O. Abillon, E. Perez","doi":"10.1051/JPHYS:0199000510220254300","DOIUrl":"https://doi.org/10.1051/JPHYS:0199000510220254300","url":null,"abstract":"Nous avons mesure les forces entre deux surfaces de mica immergees dans une phase lamellaire gonflee a l'eau (CTAB/hexanol/eau salee). Les bicouches s'orientent parallelement aux surfaces de mica. Les courbes force-distance presentent des domaines ou l'eau est continument ejectee d'entre les lamelles, et des domaines ou le systeme saute rapidement a une autre distance en ejectant des lamelles. Nous avons etudie l'effet sur les forces d'un deplacement dans le diagramme de phases a periode spatiale constante et egalement le long de la ligne de dilution","PeriodicalId":14747,"journal":{"name":"Journal De Physique","volume":"476 ","pages":"2543-2556"},"PeriodicalIF":0.0,"publicationDate":"1990-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91520417","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}
Pub Date : 1990-11-01DOI: 10.1051/JPHYS:0199000510220257100
D. Ausserré, D. Chatenay, G. Coulon, B. Collin
L'apparition de domaines circulaires en relief a la surface de films de copolymeres bisequences deposes sur un solide soumis a une trempe est due a la formation d'un ordre lamellaire dans le film qui s'accompagne d'une quantification de son epaisseur locale. En admettant que la structure des bords des domaines est une simple dislocation, les equations decrivant l'evolution temporelle de la distribution de taille des domaines sont etablies
{"title":"Growth of two dimensional domains in copolymer thin films","authors":"D. Ausserré, D. Chatenay, G. Coulon, B. Collin","doi":"10.1051/JPHYS:0199000510220257100","DOIUrl":"https://doi.org/10.1051/JPHYS:0199000510220257100","url":null,"abstract":"L'apparition de domaines circulaires en relief a la surface de films de copolymeres bisequences deposes sur un solide soumis a une trempe est due a la formation d'un ordre lamellaire dans le film qui s'accompagne d'une quantification de son epaisseur locale. En admettant que la structure des bords des domaines est une simple dislocation, les equations decrivant l'evolution temporelle de la distribution de taille des domaines sont etablies","PeriodicalId":14747,"journal":{"name":"Journal De Physique","volume":"41 1","pages":"2571-2580"},"PeriodicalIF":0.0,"publicationDate":"1990-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80773371","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}
Pub Date : 1990-11-01DOI: 10.1051/JPHYS:0199000510210242100
J. Fontanari
The performance of a Hopfield network in learning an extensive number of concepts having access only to a finite supply of typical data which exemplify the concepts is studied. The minimal number of examples which must be taught to the network in order it starts to create representations for the concepts is calculated analitically. It is shown that the mixture states play a crucial role in the creation of these representations
{"title":"Generalization in a Hopfield network","authors":"J. Fontanari","doi":"10.1051/JPHYS:0199000510210242100","DOIUrl":"https://doi.org/10.1051/JPHYS:0199000510210242100","url":null,"abstract":"The performance of a Hopfield network in learning an extensive number of concepts having access only to a finite supply of typical data which exemplify the concepts is studied. The minimal number of examples which must be taught to the network in order it starts to create representations for the concepts is calculated analitically. It is shown that the mixture states play a crucial role in the creation of these representations","PeriodicalId":14747,"journal":{"name":"Journal De Physique","volume":"13 1","pages":"2421-2430"},"PeriodicalIF":0.0,"publicationDate":"1990-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87560584","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}
Pub Date : 1990-11-01DOI: 10.1051/JPHYS:0199000510220252100
S. Avrillier, E. Tinet, E. Delettre
An accurate Monte Carlo (MC) computer model is used to calculate the reflectances (R) and transmittances (T) of isotropic scattering media for the case of collimated beam illumination and for a wide range of absorption and scattering coefficients κ and σ per unit length. The MC results are presented by means of sets of curves with distance scaling in order to give an overall understanding of the subject. A simple diagram is constructed with accurate MC results and can be used for direct graphical determination of κ and σ from R and T measurements. The effects of reflections at the boundaries are described in the last section
{"title":"Monte Carlo simulation of collimated beam transmission through turbid media","authors":"S. Avrillier, E. Tinet, E. Delettre","doi":"10.1051/JPHYS:0199000510220252100","DOIUrl":"https://doi.org/10.1051/JPHYS:0199000510220252100","url":null,"abstract":"An accurate Monte Carlo (MC) computer model is used to calculate the reflectances (R) and transmittances (T) of isotropic scattering media for the case of collimated beam illumination and for a wide range of absorption and scattering coefficients κ and σ per unit length. The MC results are presented by means of sets of curves with distance scaling in order to give an overall understanding of the subject. A simple diagram is constructed with accurate MC results and can be used for direct graphical determination of κ and σ from R and T measurements. The effects of reflections at the boundaries are described in the last section","PeriodicalId":14747,"journal":{"name":"Journal De Physique","volume":"106 1","pages":"2521-2542"},"PeriodicalIF":0.0,"publicationDate":"1990-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78969087","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}
Pub Date : 1990-11-01DOI: 10.1051/JPHYS:0199000510210239900
V. Dmitriev, Yu. M. Gufan, S. Rochal, R. Toledano
A theoretical model is proposed for the formation of quasicrystalline alloys. The icosahedral phase is known to result from a reconstructive transition of the displacive type from a parent crystalline structure. Two order parameters are involved in the transition mechanism: a displacement field which transforms a number of sublattices into icosahedral clusters, and an icosahedral density wave which breaks incommensurately the initial translational order. The main features of the model are introduced through the illustrative example of AlMnSi Un modele theorique est propose pour expliquer la formation des alliages quasicristallins. La phase icosaedrique resulte dans ce modele, d'une transition reconstructive de type displacif a partir d'une phase mere cristalline. Le mecanisme de la transition met en jeu deux parametres d'ordre distincts: un champ de deplacements qui transforme certains sous-reseaux cristallins en assemblages icosaedriques, et une onde de densite qui brise de facon incommensurable l'ordre translationnel de la phase mere. Les principaux aspects de la theorie sont introduits a travers l'exemple de AlMnSi
{"title":"Theory of the formation of quasicrystals","authors":"V. Dmitriev, Yu. M. Gufan, S. Rochal, R. Toledano","doi":"10.1051/JPHYS:0199000510210239900","DOIUrl":"https://doi.org/10.1051/JPHYS:0199000510210239900","url":null,"abstract":"A theoretical model is proposed for the formation of quasicrystalline alloys. The icosahedral phase is known to result from a reconstructive transition of the displacive type from a parent crystalline structure. Two order parameters are involved in the transition mechanism: a displacement field which transforms a number of sublattices into icosahedral clusters, and an icosahedral density wave which breaks incommensurately the initial translational order. The main features of the model are introduced through the illustrative example of AlMnSi Un modele theorique est propose pour expliquer la formation des alliages quasicristallins. La phase icosaedrique resulte dans ce modele, d'une transition reconstructive de type displacif a partir d'une phase mere cristalline. Le mecanisme de la transition met en jeu deux parametres d'ordre distincts: un champ de deplacements qui transforme certains sous-reseaux cristallins en assemblages icosaedriques, et une onde de densite qui brise de facon incommensurable l'ordre translationnel de la phase mere. Les principaux aspects de la theorie sont introduits a travers l'exemple de AlMnSi","PeriodicalId":14747,"journal":{"name":"Journal De Physique","volume":"31 1","pages":"2399-2405"},"PeriodicalIF":0.0,"publicationDate":"1990-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79443288","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}
Pub Date : 1990-11-01DOI: 10.1051/JPHYS:0199000510220260500
I. Barnes, P. Dérian, S. Hyde, B. Ninham, T. Zemb
et leurs predictions confrontees aux resultats experimentaux. Abstract. 2014 The « anomalous » fluid isotropic phase in the DDAB/tetradecane/water system differs in important ways from microemulsion phases in related systems, and is thus a useful test for models. On the basis of absolute scaled neutron and X-ray scattering data we show here that the microstructure is best characterised as a randomly folded reverse bilayer. All previously reported examples of this structure are restricted to a narrow range of composition and temperature. In this case of a stiff bilayer with low spontaneous interfacial curvature it extends over a large region of the ternary phase diagram at room temperature, the boundaries of which are explained in terms of simple geometric constraints. Other possible microstructures are
{"title":"A disordered lamellar structure in the isotropic phase of a ternary double-chain surfactant system","authors":"I. Barnes, P. Dérian, S. Hyde, B. Ninham, T. Zemb","doi":"10.1051/JPHYS:0199000510220260500","DOIUrl":"https://doi.org/10.1051/JPHYS:0199000510220260500","url":null,"abstract":"et leurs predictions confrontees aux resultats experimentaux. Abstract. 2014 The « anomalous » fluid isotropic phase in the DDAB/tetradecane/water system differs in important ways from microemulsion phases in related systems, and is thus a useful test for models. On the basis of absolute scaled neutron and X-ray scattering data we show here that the microstructure is best characterised as a randomly folded reverse bilayer. All previously reported examples of this structure are restricted to a narrow range of composition and temperature. In this case of a stiff bilayer with low spontaneous interfacial curvature it extends over a large region of the ternary phase diagram at room temperature, the boundaries of which are explained in terms of simple geometric constraints. Other possible microstructures are","PeriodicalId":14747,"journal":{"name":"Journal De Physique","volume":"6 1","pages":"2605-2628"},"PeriodicalIF":0.0,"publicationDate":"1990-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76448808","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}
Pub Date : 1990-11-01DOI: 10.1051/JPHYS:0199000510210239500
S. Komura, A. Baumgärtner
The spectral dimension d s of polymerized and fluid self-avoiding vesicles are investigated by Monte Carlo methods. For both cases we obtained d s =2, which indicates that these surfaces belong to the same class of «microcanonical» surfaces
用蒙特卡罗方法研究了聚合和流体自避囊泡的光谱维数。对于这两种情况，我们得到了d s =2，这表明这些曲面属于同一类“微正则”曲面
{"title":"Spectral dimension of fluid membranes","authors":"S. Komura, A. Baumgärtner","doi":"10.1051/JPHYS:0199000510210239500","DOIUrl":"https://doi.org/10.1051/JPHYS:0199000510210239500","url":null,"abstract":"The spectral dimension d s of polymerized and fluid self-avoiding vesicles are investigated by Monte Carlo methods. For both cases we obtained d s =2, which indicates that these surfaces belong to the same class of «microcanonical» surfaces","PeriodicalId":14747,"journal":{"name":"Journal De Physique","volume":"33 1","pages":"2395-2398"},"PeriodicalIF":0.0,"publicationDate":"1990-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87999073","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}
Pub Date : 1990-11-01DOI: 10.1051/JPHYS:0199000510220250100
M. Altaisky, S. S. Moiseev
The path-integral approach to classical Hamiltonian dynamics (i.e. the functional-integral representation of classical transition probabilities), recently developed by Gozzi, is applied for studying the perfect fluid. In this way, by studying the symplectic structure of volume-preserving diffeomorphism the Thompson circulation theorem is shown to be equivalent to the conservation of ghost charge ― one of the generators related to the (graded) ISp(2) symmetry present in any Hamiltonian system
{"title":"Supersymmetry in hydrodynamics: vorticity as a ghost charge","authors":"M. Altaisky, S. S. Moiseev","doi":"10.1051/JPHYS:0199000510220250100","DOIUrl":"https://doi.org/10.1051/JPHYS:0199000510220250100","url":null,"abstract":"The path-integral approach to classical Hamiltonian dynamics (i.e. the functional-integral representation of classical transition probabilities), recently developed by Gozzi, is applied for studying the perfect fluid. In this way, by studying the symplectic structure of volume-preserving diffeomorphism the Thompson circulation theorem is shown to be equivalent to the conservation of ghost charge ― one of the generators related to the (graded) ISp(2) symmetry present in any Hamiltonian system","PeriodicalId":14747,"journal":{"name":"Journal De Physique","volume":"101 1","pages":"2501-2504"},"PeriodicalIF":0.0,"publicationDate":"1990-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87008390","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}
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