Documents disponibles écrits par cet auteur

Effects of rotation of benzene rings on diffusion of solvents in polymer melts / Makoto Asai in Industrial & engineering chemistry research, Vol. 50 N° 6 (Mars 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3280–3286 Titre : Effects of rotation of benzene rings on diffusion of solvents in polymer melts Type de document : texte imprimé Auteurs : Makoto Asai, Auteur ; Megumi Awata, Auteur ; Yasuhiro Koike, Auteur Année de publication : 2011 Article en page(s) : pp. 3280–3286 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Solvents  Polymer Résumé : Diffusion of a solvent through a polymer is one of the important phenomena in the industry. Such diffusion phenomena, however, have complicated multibody problems, and in general, they are difficult to tightly control. In this study, it was our objective to investigate the effects of the structure of the solvent on the diffusion in polymers, in particular, the effects of the structure on concentration dependence of a mutual diffusion coefficient. Knowledge pertaining to chemical structures and diffusion is very useful for controlling the diffusion phenomena because it allows the design of a solvent possessing the desired diffusion. The diffusion of diphenylsulfide and dibenzothiophene in poly(methyl methacrylate) (PMMA) was investigated. Diphenylsulfide and dibenzothiophene have nearly identical molecular structures and differ in a benzene ring with or without rotation within the molecule. The results indicated that the dependence of the mutual diffusion coefficient was significantly affected by the rotation of the benzene ring present in the molecule. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102082r [article] Effects of rotation of benzene rings on diffusion of solvents in polymer melts [texte imprimé] / Makoto Asai, Auteur ; Megumi Awata, Auteur ; Yasuhiro Koike, Auteur . - 2011 . - pp. 3280–3286. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 6 (Mars 2011) . - pp. 3280–3286 Mots-clés : Solvents  Polymer Résumé : Diffusion of a solvent through a polymer is one of the important phenomena in the industry. Such diffusion phenomena, however, have complicated multibody problems, and in general, they are difficult to tightly control. In this study, it was our objective to investigate the effects of the structure of the solvent on the diffusion in polymers, in particular, the effects of the structure on concentration dependence of a mutual diffusion coefficient. Knowledge pertaining to chemical structures and diffusion is very useful for controlling the diffusion phenomena because it allows the design of a solvent possessing the desired diffusion. The diffusion of diphenylsulfide and dibenzothiophene in poly(methyl methacrylate) (PMMA) was investigated. Diphenylsulfide and dibenzothiophene have nearly identical molecular structures and differ in a benzene ring with or without rotation within the molecule. The results indicated that the dependence of the mutual diffusion coefficient was significantly affected by the rotation of the benzene ring present in the molecule. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie102082r

Methodological approach to control the refractive index profile of graded-index polymer optical fiber / Makoto Asai in Industrial & engineering chemistry research, Vol. 50 N° 7 (Avril 2011) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 50 N° 7 (Avril 2011) . - pp. 3895–3899 Titre : Methodological approach to control the refractive index profile of graded-index polymer optical fiber Type de document : texte imprimé Auteurs : Makoto Asai, Auteur ; Yoshiki Mukawa, Auteur ; Satoshi Takahashi, Auteur Année de publication : 2011 Article en page(s) : pp. 3895–3899 Note générale : Chimie industrielle Langues : Anglais (eng) Mots-clés : Polymer  optical  Fiber Résumé : The graded-index polymer optical fiber (GI-POF) is a promising candidate for high-speed communication medium for very short reach networks such as home networks and office local area networks (LANs). It is well-known that there is an optimum refractive index profile to maximize bandwidth properties of GI-POF when the profile is expressed by the power law equation. The interfacial-gel polymerization technique, one of the major conventional fabrication methods of GI-POF, has many processes, and the formation mechanism of refractive index profiles intricately depends on many parameters of fabrication conditions. Thus is very difficult to control and form an optimum radial refractive index profile in the GI-POF. Recently, the coextrusion process has been proposed for mass production of GI-POF. In this process, the forming process of refractive index profiles can be expressed by a simple advection−diffusion equation. Therefore, we investigated the general methodology to control refractive index profiles by numerically solving the advection−diffusion equation. On the basis of our data, it was determined that refractive index profiles could be controlled by adjusting diffusion temperature and core ratio. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101888y [article] Methodological approach to control the refractive index profile of graded-index polymer optical fiber [texte imprimé] / Makoto Asai, Auteur ; Yoshiki Mukawa, Auteur ; Satoshi Takahashi, Auteur . - 2011 . - pp. 3895–3899. Chimie industrielle Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 50 N° 7 (Avril 2011) . - pp. 3895–3899 Mots-clés : Polymer  optical  Fiber Résumé : The graded-index polymer optical fiber (GI-POF) is a promising candidate for high-speed communication medium for very short reach networks such as home networks and office local area networks (LANs). It is well-known that there is an optimum refractive index profile to maximize bandwidth properties of GI-POF when the profile is expressed by the power law equation. The interfacial-gel polymerization technique, one of the major conventional fabrication methods of GI-POF, has many processes, and the formation mechanism of refractive index profiles intricately depends on many parameters of fabrication conditions. Thus is very difficult to control and form an optimum radial refractive index profile in the GI-POF. Recently, the coextrusion process has been proposed for mass production of GI-POF. In this process, the forming process of refractive index profiles can be expressed by a simple advection−diffusion equation. Therefore, we investigated the general methodology to control refractive index profiles by numerically solving the advection−diffusion equation. On the basis of our data, it was determined that refractive index profiles could be controlled by adjusting diffusion temperature and core ratio. DEWEY : 660 ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie101888y