Kazuki Nakanishi - Academia.edu (original) (raw)
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Papers by Kazuki Nakanishi
New Journal of Chemistry, Mar 17, 2014
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MRS Proceedings, 2007
ABSTRACT Thermoporometry was employed to monitor the mesopore evolution in wet, drying and heat-t... more ABSTRACT Thermoporometry was employed to monitor the mesopore evolution in wet, drying and heat-treatment stages of monolithic macro/mesoporous silica with SBA-15 like structure. Direct comparison of mesopores in wet state was only possible with the samples extracted with sulfuric acid. In good agreement with the preceding study, the sulfuric acid not only removed the surfactant but also modified the silica gel network into that with reduced amount of micropores and increased stability against the drying stress. Thermoporometry revealed that the structural evolution takes place completely in the wet condition, which accompanies a decrease in the thickness of non-freezable water.
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RSC Advances, 2013
ABSTRACT Starting from an aqueous solution, porous zinc ferrite-based xerogel monoliths have been... more ABSTRACT Starting from an aqueous solution, porous zinc ferrite-based xerogel monoliths have been prepared via a sol–gel route accompanied by phase separation mediated by propylene oxide in the presence of poly(acrylamide). The xerogels possess well-defined macropores, and the macroporous morphologies could be easily controlled (macropore size ranges from 0.55 to 1.29 μm) by simply changing the starting composition. As-dried xerogel samples were amorphous under X-ray diffraction, while heat-treatment in air brought about the formation of spinel type ferrite phase, ZnFe2O4. Calcination under Ar atmosphere allowed the crystallization of various iron-based phases/carbon composites (Fe3O4, Fe1-δO, Fe3N, Fe4N, Fe3C, and Fe). Samples heated under Ar flow exhibited hierarchical pore structures, including continuous macropores, in addition to mesopores and micropores embedded in the carbon-containing composite matrices.
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MRS Proceedings, 2008
ABSTRACT
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Convertech E Print, Mar 1, 2014
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Chemistry of Materials, 2008
ABSTRACT
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Journal of the American Ceramic Society, 2010
ABSTRACT Monolithic titania (TiO2) with multiscale porous structures have been successfully prepa... more ABSTRACT Monolithic titania (TiO2) with multiscale porous structures have been successfully prepared via the sol–gel route accompanied by phase separation utilizing a chelating agent and mineral salt. The TiO2 gels obtained possess well-defined macropores derived from spinodal decomposition and mesopores as interstices of anatase TiO2 nanocrystallites. Most of the chelating agent were removed by hydrolysis and subsequent decarbonation through the gradual solvent exchange from ethanol to water. The TiO2 particles comprising TiO2 gel skeletons spontaneously converted from amorphous to anatase through the solvent exchange process in a mild condition at 60°C. The present method of the fabrication of porous TiO2 monoliths is advantageous for widespread applications because the reaction occurs under an almost neutral condition and does not require a hydrothermal process, which was indispensable to strengthen the monolith in the method previously reported.
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Analytical Chemistry, Oct 1, 1996
Continuous porous silica rods consisting of a mesoporous (pore size, 14 or 25 nm) silica skeleton... more Continuous porous silica rods consisting of a mesoporous (pore size, 14 or 25 nm) silica skeleton of ∼1 μm size and through-pores of ∼1.7 μm were prepared and derivatized to C(18) phase by on-column reaction with octadecyldimethyl-(N,N-diethylamino)silane. The C(18) silica rods gave plate heights of 10-20 μm for aromatic hydrocarbons in 80% methanol and 20-40 μm for insulin in acetonitrile-water mixtures in the presence of trifluoroacetic acid. The performance of the silica rods was much better at a high flow rate than that of conventional columns packed with 5 μm C(18) silica particles having 12 and 30 nm pores, especially for high molecular weight species.
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New J Chem, Jan 6, 2014
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Polymer Journal, 2006
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Colloids and Surfaces a Physicochemical and Engineering Aspects, Jun 1, 2007
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Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi, 2007
ABSTRACT
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Trac, 1998
High performance liquid chromatography (HPLC) has become one of the most used methods for the ana... more High performance liquid chromatography (HPLC) has become one of the most used methods for the analysis of compound mixtures in industry, especially for the quality control of products. Nowadays productivity is the major and dominant upcoming issue, i.e. the goal is to drastically reduce the analysis time and cost per analysis. The solution of the task is higher throughput and faster HPLC methods. Here we describe a new monolithic type of HPLC column, the SilicaROD™ column, which permits the fast HPLC separation of compound mixtures within a few minutes.
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Advanced Functional Materials, Jun 6, 2013
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Macromolecules, Oct 14, 2008
ABSTRACT
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Langmuir, Jul 1, 2003
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Journal of Sol Gel Science and Technology, 2003
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Chem Mater, 2006
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New Journal of Chemistry, Mar 17, 2014
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MRS Proceedings, 2007
ABSTRACT Thermoporometry was employed to monitor the mesopore evolution in wet, drying and heat-t... more ABSTRACT Thermoporometry was employed to monitor the mesopore evolution in wet, drying and heat-treatment stages of monolithic macro/mesoporous silica with SBA-15 like structure. Direct comparison of mesopores in wet state was only possible with the samples extracted with sulfuric acid. In good agreement with the preceding study, the sulfuric acid not only removed the surfactant but also modified the silica gel network into that with reduced amount of micropores and increased stability against the drying stress. Thermoporometry revealed that the structural evolution takes place completely in the wet condition, which accompanies a decrease in the thickness of non-freezable water.
Bookmarks Related papers MentionsView impact
RSC Advances, 2013
ABSTRACT Starting from an aqueous solution, porous zinc ferrite-based xerogel monoliths have been... more ABSTRACT Starting from an aqueous solution, porous zinc ferrite-based xerogel monoliths have been prepared via a sol–gel route accompanied by phase separation mediated by propylene oxide in the presence of poly(acrylamide). The xerogels possess well-defined macropores, and the macroporous morphologies could be easily controlled (macropore size ranges from 0.55 to 1.29 μm) by simply changing the starting composition. As-dried xerogel samples were amorphous under X-ray diffraction, while heat-treatment in air brought about the formation of spinel type ferrite phase, ZnFe2O4. Calcination under Ar atmosphere allowed the crystallization of various iron-based phases/carbon composites (Fe3O4, Fe1-δO, Fe3N, Fe4N, Fe3C, and Fe). Samples heated under Ar flow exhibited hierarchical pore structures, including continuous macropores, in addition to mesopores and micropores embedded in the carbon-containing composite matrices.
Bookmarks Related papers MentionsView impact
MRS Proceedings, 2008
ABSTRACT
Bookmarks Related papers MentionsView impact
Convertech E Print, Mar 1, 2014
Bookmarks Related papers MentionsView impact
Chemistry of Materials, 2008
ABSTRACT
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Journal of the American Ceramic Society, 2010
ABSTRACT Monolithic titania (TiO2) with multiscale porous structures have been successfully prepa... more ABSTRACT Monolithic titania (TiO2) with multiscale porous structures have been successfully prepared via the sol–gel route accompanied by phase separation utilizing a chelating agent and mineral salt. The TiO2 gels obtained possess well-defined macropores derived from spinodal decomposition and mesopores as interstices of anatase TiO2 nanocrystallites. Most of the chelating agent were removed by hydrolysis and subsequent decarbonation through the gradual solvent exchange from ethanol to water. The TiO2 particles comprising TiO2 gel skeletons spontaneously converted from amorphous to anatase through the solvent exchange process in a mild condition at 60°C. The present method of the fabrication of porous TiO2 monoliths is advantageous for widespread applications because the reaction occurs under an almost neutral condition and does not require a hydrothermal process, which was indispensable to strengthen the monolith in the method previously reported.
Bookmarks Related papers MentionsView impact
Analytical Chemistry, Oct 1, 1996
Continuous porous silica rods consisting of a mesoporous (pore size, 14 or 25 nm) silica skeleton... more Continuous porous silica rods consisting of a mesoporous (pore size, 14 or 25 nm) silica skeleton of ∼1 μm size and through-pores of ∼1.7 μm were prepared and derivatized to C(18) phase by on-column reaction with octadecyldimethyl-(N,N-diethylamino)silane. The C(18) silica rods gave plate heights of 10-20 μm for aromatic hydrocarbons in 80% methanol and 20-40 μm for insulin in acetonitrile-water mixtures in the presence of trifluoroacetic acid. The performance of the silica rods was much better at a high flow rate than that of conventional columns packed with 5 μm C(18) silica particles having 12 and 30 nm pores, especially for high molecular weight species.
Bookmarks Related papers MentionsView impact
New J Chem, Jan 6, 2014
Bookmarks Related papers MentionsView impact
Polymer Journal, 2006
Bookmarks Related papers MentionsView impact
Colloids and Surfaces a Physicochemical and Engineering Aspects, Jun 1, 2007
Bookmarks Related papers MentionsView impact
Nippon Seramikkusu Kyokai Gakujutsu Ronbunshi, 2007
ABSTRACT
Bookmarks Related papers MentionsView impact
Trac, 1998
High performance liquid chromatography (HPLC) has become one of the most used methods for the ana... more High performance liquid chromatography (HPLC) has become one of the most used methods for the analysis of compound mixtures in industry, especially for the quality control of products. Nowadays productivity is the major and dominant upcoming issue, i.e. the goal is to drastically reduce the analysis time and cost per analysis. The solution of the task is higher throughput and faster HPLC methods. Here we describe a new monolithic type of HPLC column, the SilicaROD™ column, which permits the fast HPLC separation of compound mixtures within a few minutes.
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Advanced Functional Materials, Jun 6, 2013
Bookmarks Related papers MentionsView impact
Macromolecules, Oct 14, 2008
ABSTRACT
Bookmarks Related papers MentionsView impact
Langmuir, Jul 1, 2003
Bookmarks Related papers MentionsView impact
Journal of Sol Gel Science and Technology, 2003
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Chem Mater, 2006
Bookmarks Related papers MentionsView impact