研究者詳細 - 亀島　欣一

MISC - 亀島　欣一

分割表示 97 件中 61 - 80 件目／全件表示 >>

Preparation and simultaneous ion uptake properties of CaO-Fe2O3-SiO2 compounds

Atsushi Kobayashi, Fahmida Gulshan, Yoshikazu Kameshima, Akira Nnakajima, Kiyoshi Okada

JOURNAL OF THE CERAMIC SOCIETY OF JAPAN 116 ( 1350 ) 187 - 191 2008年2月

記述言語：英語出版者・発行元：CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI

CaO-Fe2O3-SiO2 (CFS) compounds were prepared from mixtures of Ca(OH)(2), FeOOH and SiO2 and their simultaneous uptake properties for cations and anions were investigated. The starting powders were mixed in various ratios using a planetary ball mill and heated at various temperatures in air and flowing N-2 atmospheres. Amorphous compounds were formed by heating up to <600 degrees C while hematite (alpha-Fe2O3) was crystallized at >= 600 degrees C and calcium silicates and/or calcium iron silicates at >= 800 degrees C. Simultaneous ion uptake experiments were carried out by a batch method using solutions containing same concentrations of Ni2+, NH4+ and H2PO4-. The samples heated at 600 degrees C showed the highest ion uptake ability. The uptake abilities were higher for Ni2+ and H2PO4- than for NH4+ and increased with increasing CaO content in the CFSs. The uptake abilities for three ions enhanced by heating the samples in flowing N-2. The simultaneous uptake mechanisms are thought to be similar to those observed in the CAS compounds, i.e. ligand change (Ca2+ -> Ni2+), compound precipitation and adsorption. The CFS compounds have the following advantages compared with CaO-Al2O3-SiO2 (CAS); (1) higher uptake ability for phosphate ions (a model for harmful oxyanions) and (2) easy separation of a contaminated sorbent from the solution after uptake using a magnet.

DOI： 10.2109/jcersj2.116.187

Voltage swing interval effects on photocatalytic decomposition of 1,4-dioxane in aqueous media using TiO2-coated stainless mesh

Sayaka Yanagida, Akira Nakajima, Yoshikazu Kameshima, Kiyoshi Okada

JOURNAL OF THE CERAMIC SOCIETY OF JAPAN 116 ( 1350 ) 181 - 186 2008年2月

記述言語：英語出版者・発行元：CERAMIC SOC JAPAN-NIPPON SERAMIKKUSU KYOKAI

This study investigates the effects of a voltage swing interval on 1,4-dioxane decomposition in aqueous media. The concentration of 1,4-dioxane decreases with the decreasing voltage swing interval, but the change is small. In contrast, the concentration of EGDF increases with the decreasing interval. Its difference is much greater than that of 1,4-dioxane. These results suggest that the diffusion constant of EGDF in a pore structure differs from that of 1,4-dioxane and that the response to the voltage swing interval depends on the chemical species. For effective water purification using this system, proper material design and optimization of operation conditions are necessary.

DOI： 10.2109/jcersj2.116.181

Sliding behavior of water droplets on line-patterned hydrophobic surfaces

Shunsuke Suzuki, Akira Nakajima, Kouichi Tanaka, Munetoshi Sakai, Ayako Hashimoto, Naoya Yoshida, Yoshikazu Kameshima, Kiyoshi Okada

APPLIED SURFACE SCIENCE 254 ( 6 ) 1797 - 1805 2008年1月

記述言語：英語出版者・発行元：ELSEVIER SCIENCE BV

We prepared line-patterned hydrophobic surfaces using fluoroalkylsilane (FAS) and octadecyltrimethoxysilane (ODS) then investigated the effect of line direction on sliding behavior of water droplets by direct observation of the actual droplet motion during sliding. Water droplets slide down with a periodic large deformation of the contact line and sliding velocity fluctuation that occurred when they crossed over the 500-mu m ODS line regions in FAS regions on a Si surface tilted at 35 degrees. These behaviors are less marked for motion on a 100-mu m line surface, or on lines oriented parallel to the slope direction. Smaller droplets slide down with greater displacement in the line direction on 500-mu m line patterning when the lines were rotated at 13 degrees in-plane for the slope direction. This sliding behavior depended on the droplet size and rotation angle, and is accountable by the balance between gravitational and retentive forces. (C) 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.apsusc.2007.07.171

Slipping and rolling ratio of sliding acceleration for a water droplet sliding on fluoroalkylsilane coatings of different roughness

Shunsuke Suzuki, Akira Nakajima, Munetoshi Sakai, Yuu Sakurada, Naoya Yoshida, Ayako Hashimoto, Yoshikazu Kameshima, Kiyoshi Okada

CHEMISTRY LETTERS 37 ( 1 ) 58 - 59 2008年1月

記述言語：英語出版者・発行元：CHEMICAL SOC JAPAN

The effect of surface roughness on the internal fluidity of a water droplet during sliding on an inclined Si surface treated fluoroalkylsilane (FAS) was investigated using particle image velocimetry (PIV). A water droplet slid down by caterpillar-like rotation flow with or without slippage on the solid-liquid interface. The slipping/rolling ratio on the sliding acceleration depended on the surface roughness; the droplet advanced on the rough surface mainly by the rolling mechanism.

DOI： 10.1246/cl.2008.58

Direct Measurement of the Motion of Water Droplets on a Hydrophobic Self-assembled Monolayer Surface under Airflow

A. Hashimoto, M. Sakai, N. Yoshida, S. Suzuki, Y. Kameshima, A. Nakajima

J. Surf. Finishing Soc. Jpn. 59 ( 12 ) 907 - 912 2008年

記述言語：英語出版者・発行元：一般社団法人表面技術協会

A wind tunnel to produce a uniform air stream and a high-speed camera system assembled for this study enabled direct and simultaneous measurements of sliding droplets' shape and acceleration. Using this system, wind velocity dependence of deformation and the moving acceleration of a water droplet on an inclined octadecyltrimethoxysilane (ODS) coating were investigated. The motions of a water droplet in an air stream are classifiable into three : sliding, stopping, and climbing. In the sliding zone, the sliding acceleration decreases with increasing wind velocity. During stopping, the droplet shape changes from a forward-bent to backward-bent posture against the surface inclination. In the climbing zone under large wind velocity, water droplets have large climbing acceleration with large shape deformation.

DOI： 10.4139/sfj.59.907

高酸量の酸化物ゾル／スメクタイト複合体の作製

亀島欣一, 岡田清

化学工業 59 ( 5 ) 337 - 342 2008年

Properties of TiO2 prepared by acid treatment of BaTiO3

Kiyoshi Okada, Tomoki Yanagisawa, Yoshikazu Kameshima, Akira Nakajima

MATERIALS RESEARCH BULLETIN 42 ( 11 ) 1921 - 1929 2007年11月

記述言語：英語出版者・発行元：PERGAMON-ELSEVIER SCIENCE LTD

TiO3 powders were prepared by acid treatment of BaTiO3 and their properties were investigated. The BaTiO3 powder was subjected to HNO3 in concentrations ranging from 10(-3) to 8 M at 90 degrees C for 0.5-6 h. Dissolution of BaTiO3 and precipitation of TiO2 occurred at acid concentrations of 2-5 M. BaTiO3 dissolves completely to form a clear solution at reaction times of 0.5-1 h, but a rutile precipitate is formed after 2 h of acid treatment. By contrast, anatase is precipitated by adjusting the pH of the clear solution to 2-3 using NaOH or NH4OH solution. The rutile crystals were small and rod-shaped, consisting of many small coherent domains connected by grain boundaries with small inclination angles and edge dislocations, giving them a high specific surface area (S-BET). With increasing HNO3 concentration, the SBET value increased from 100 to 170 m(2)/g while the crystallite size decreased from 25 to 11 nm. The anatase crystals obtained here were very small equi-axial particles with a smaller crystallite size than the rutile and S-BET values of about 270 m(2)/g (higher than the rutile samples). The photocatalytic activity of these TiO3 was determined from the decomposition rate of Methylene Blue under ultraviolet irradiation. Higher decomposition rates were obtained with larger crystallite sizes resulting from heat treatment. The maximum decomposition rates were obtained in samples heated at 500-600 degrees C. The photocatalytic activity of the TiO3 was found to depend more strongly on the sample crystallite size than on S-BET. (C) 2006 Elsevier Ltd. All rights reserved.

DOI： 10.1016/j.materresbull.2006.12.011

Synthesis and characterization of mesoporous silica from selectively acid-treated saponite as the precursors

Kiyoshi Okada, Hisako Yoshizaki, Yoshikazu Kameshima, Akira Nakajima, Chengala D. Madhusoodana

JOURNAL OF COLLOID AND INTERFACE SCIENCE 314 ( 1 ) 176 - 183 2007年10月

記述言語：英語出版者・発行元：ACADEMIC PRESS INC ELSEVIER SCIENCE

Mesoporous silicas were synthesized by hydrothermal treatment of selectively acid-treated saponite (an ideal structural formula: Na1/3Mg3-(Si11/3Al1/3)O-10(OH)(2)), having a 2:1 type layered structure as the silica source and its porous properties were examined and compared with that from kaolinite (an ideal structural formula: Al2Si2O5(OH)(4)), having a 1:1 type layered structure. Synthetic saponite was selectively leached in H2SO4 solutions with various concentrations (0.05-1 M) at 70 degrees C for 0.5 h. The resulting products (precursors) were mixed with cetyltrimethylammonium bromide (CTABr), NaOH and H2O, hydrothermally treated at 110 degrees C and removed the CTABr by calcining at 560 degrees C. A hexagonal mesoporous phase was obtained with higher Si/(Al(+Mg)) ratios of the resulting precursors. The XRD patterns of these products show the peaks assigned by a hexagonal lattice with a(0) = 4.0-4.6 nm and the crystatlinity becomes higher with higher Si/(Al(+Mg)) ratios of the precursors. The specific surface area (S-BET) values of the present mesoporous silicas range from 800 to 1100 m(2)/g at CTABr/precursor = 0.1 and although they are not as high as those from precursors prepared from calcining and acid-treatment of kaolinite (1420 m(2)/g), they are increased to 14001500 m2/g by increasing the ratio CTABr/precursor >= 0.2. The reason for the difference in the optimum preparation conditions between saponite and kaolinite may be attributed to the difference in the linkage of the SiO4 tetrahedra in these precursors (i.e. layered or framework structures), which result in great differences in the selective leaching rates and structures of the resulting silica-rich products. (c) 2007 Elsevier Inc. All rights reserved.

DOI： 10.1016/j.jcis.2007.05.036

A7 メソポーラスシリカの多孔体特性に与えるカオリナイトの結晶性の影響

岡田清, 吉崎久子, 亀島欣一, 中島章

粘土科学討論会講演要旨集 ( 51 ) 44 - 45 2007年9月

B14 インドメタシン/層状複水酸化物複合体の作製とその放出挙動

亀島欣一, 小幡宏美, 中島章, 岡田清

粘土科学討論会講演要旨集 ( 51 ) 116 - 117 2007年9月

P31 アスコルビン酸ナトリウム/層状複水酸化物複合体の作製とその評価

佐々木洋和, 亀島欣一, 中島章, 岡田清

粘土科学討論会講演要旨集 ( 51 ) 208 - 209 2007年9月

Freezing of water droplets on silicon surfaces coated with various silanes

Shunsuke Suzuki, Akira Nakajima, Naoya Yoshida, Munetoshi Sakai, Ayako Hashimoto, Yoshikazu Kameshima, Kiyoshi Okada

CHEMICAL PHYSICS LETTERS 445 ( 1-3 ) 37 - 41 2007年9月

記述言語：英語出版者・発行元：ELSEVIER SCIENCE BV

The freezing behavior of a supercooled water droplet on a silicon surface treated with using various silanes was observed directly using a high-speed camera system. Freezing stability is best ensured by heterogeneous nucleation from a three-phase (solid-liquid-air)- contact line. Differential scanning calorimetry measurements revealed that the freezing temperature of a supercooled water droplet on a fluoro-alkylsilane monolayer was lower than that of alkylsilane. Interaction between the fluorocarbon and water molecule, in addition to structural characteristics of silanes, might play an important role in the heterogeneous nucleation of supercooled water. (C) 2007 Published by Elsevier B.V.

DOI： 10.1016/j.cplett.2007.07.066

Effect of electrification conditions on the freezing of supercooled water droplets on a hydrophobic coating

Akira Nakajima, Akihito Imase, Shunsuke Suzuki, Naoya Yoshida, Munetoshi Sakai, Ayako Hashimoto, Yoshikazu Kameshima, Hiroshi Toshiyoshi, Kiyoshi Okada

CHEMISTRY LETTERS 36 ( 8 ) 1020 - 1021 2007年8月

記述言語：英語出版者・発行元：CHEMICAL SOC JAPAN

The effects of electrification processes on ice nucleation on an octadecanethiol (ODT) coating were investigated under two different conditions. Electrification provides the driving force of the movement to the three-phase contact line. This change promotes ice nucleation on the supercooled water droplet. In contrast, electrification before cooling inhibits freezing, probably because of the limitation of orientational freedom by the interaction between the surface charge and the dipole moment of water molecules.

DOI： 10.1246/cl.2007.1020

Hydrophobicity and freezing of a water droplet on fluoroalkylsilane coatings with different roughnesses

Shunsuke Suzuki, Akira Nakajima, Naoya Yoshida, Munetoshi Sakai, Ayako Hashimoto, Yoshikazu Kameshima, Kiyoshi Okada

LANGMUIR 23 ( 17 ) 8674 - 8677 2007年8月

記述言語：英語出版者・発行元：AMER CHEMICAL SOC

Smooth (Ra approximate to 0. 1 nm) and rough (Ra approximate to 20 nm) coatings of 1H, 1H,2H,2H-perfluorodecyltrimethoxysilane (FAS17) were prepared by controlling process conditions. The water contact angles for the smooth and rough coatings were similar (107 degrees and 110 degrees, respectively), but their sliding angles differed considerably (10 degrees and 27 degrees, respectively). The surface potential on the smooth coating, assessed using Kelvin force microscopy, showed a sharp distribution, but that on the rough coating ranged widely, implying large chemical heterogeneity including residual SiOH groups. The freezing temperature of a supercooled water droplet on the rough coating was higher than that on the smooth coating.

DOI： 10.1021/la701077p

Bioactivity of CaSiO3/poly-lactic acid (PLA) composites prepared by various surface loading methods of CaSiO3 powder

Kiyoshi Okada, Fumikazu Hasegawa, Yoshikazu Kameshima, Akira Nakajima

JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE 18 ( 8 ) 1605 - 1612 2007年8月

記述言語：英語出版者・発行元：SPRINGER

Mixing bioactive ceramic powders with polymers is an effective method for generating bioactivity to the polymer-matrix composites but it is necessary to incorporate up to 40 vol% of bioactive ceramic powder. However, such a high mixing ratio offsets the advantages of the flexibility and formability of polymer matrix and it would be highly advantageous to lower the mixing ratio. Since surface loading of ceramic powders in the polymer is thought to be an effective way of reducing the mixing ratio of the ceramic powder while maintaining bioactive activity, CaSiO3/poly-lactic acid (PLA) composites were prepared by three methods; (1) casting, (2) spin coating and (3) hot pressing. In methods (1) and (2), a suspension was prepared by dissolving PLA in chloroform and dispersing CaSiO3 powder in it. The suspension was cast and dried to form a film in the case of method (1) while it was spincoated on a PLA substrate in method (2). In method (3), CaSiO3 powder was surface loaded on to a PLA substrate by hot-pressing. The bioactivity of these samples was investigated in vitro using simulated body fluid (SBF). Apatite formation was not observed in the samples prepared by method (1) but some apatite formation was achieved by mixing polyethylene glycol (PEG) with the PLA, producing a porous polymer matrix. In method (2), apatite was clearly observed after soaking for 7 days. Enhanced apatite formation was observed in method (3), the thickness of the resulting apatite layers becoming about 20 mu m after soaking for 14 days. Since the amount of CaSiO3 powder used in these samples was only <= 0.4 vol%, it is concluded that this preparation method is very effective in generating bioactivity in polymer-matrix composites by loading with only very small amounts of ceramic powder.

DOI： 10.1007/s10856-007-3059-9

Photoinduced surface roughness variation in polycrystalline TiO2 thin films under different atmospheres

Naoki Arimitsu, Akira Nakajima, Ken-Ichi Katsumata, Tadashi Shiota, Toshiya Watanabe, Naoya Yoshida, Yoshikazu Karneshima, Kiyoshi Okada

JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY A-CHEMISTRY 190 ( 1 ) 53 - 57 2007年7月

記述言語：英語出版者・発行元：ELSEVIER SCIENCE SA

For this study, we evaluated photoinduced surface roughness variation of polycrystalline anatase thin films under different atmospheres using atomic force microscopy (AFM). A TiO2 thin film with large grains was prepared using the sol-gel process and vacuum ultraviolet (VUV) irradiation before firing. Upon UV illumination, the surface image became blurred with an apparent surface roughness increase in ambient air. The appearance of this image change was delayed in dry air, and was not observed in dry nitrogen. These results imply that this photoinduced surface change is related to water adsorption from the atmosphere. (c) 2007 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.jphotochem.2007.03.013

Bioactivity of CaSiO3/poly-lactic acid (PLA) composites prepared by various surface loading methods of CaSiO3 powder

Kiyoshi Okada, Fumikazu Hasegawa, Yoshikazu Kameshima, Akira Nakajima

JOURNAL OF MATERIALS SCIENCE-MATERIALS IN MEDICINE 18 ( 5 ) 899 - 907 2007年5月

記述言語：英語出版者・発行元：SPRINGER

Mixing bioactive ceramic powders with polymers is an effective method for generating bioactivity to the polymer-matrix composites but it is necessary to incorporate up to 40 vol% of bioactive ceramic powder. However, such a high mixing ratio offsets the advantages of the flexibility and formability of polymer matrix and it would be highly advantageous to lower the mixing ratio. Since surface loading of ceramic powders in the polymer is thought to be an effective way of reducing the mixing ratio of the ceramic powder while maintaining bioactive activity, CaSiO3/poly-lactic acid (PLA) composites were prepared by three methods; (1) casting, (2) spin coating and (3) hot pressing. In methods (1) and (2), a suspension was prepared by dissolving PLA in chloroform and dispersing CaSiO3 powder in it. The suspension was cast and dried to form a film in the case of method (1) while it was spin-coated on a PLA substrate in method (2). In method (3), CaSiO3 powder was surface loaded on to a PLA substrate by hot pressing. The bioactivity of these samples was investigated in vitro using simulated body fluid (SBF). Apatite formation was not observed in the samples prepared by method (1) but some apatite formation was achieved by mixing polyethylene glycol (PEG) with the PLA, producing a porous polymer matrix. In method (2), apatite was clearly observed after soaking for 7 days. Enhanced apatite formation was observed in method (3), the thickness of the resulting apatite layers becoming about 20 mu m after soaking for 14 days. Since the amount of CaSiO3 powder used in these samples was only <= 0.4 vol%, it is concluded that this preparation method is very effective in generating bioactivity in polymer-matrix composites by loading with only very small amounts of ceramic powder.

DOI： 10.1007/s10856-006-0094-x

Preparation of cobalt-titanium dioxide nanocomposite films by combining inverse micelle method and plasma treatment

Naoki Arimitsu, Akira Nakajima, Yoshikazu Kameshima, Yuko Shibayama, Hisashi Ohsaki, Kiyoshi Okada

MATERIALS LETTERS 61 ( 11-12 ) 2173 - 2177 2007年5月

記述言語：英語出版者・発行元：ELSEVIER SCIENCE BV

We investigated the processing of a metal nanogranular thin film of Co-Ti-O system by combining a colloidal wet process (inverse micelle method) and a dry process (plasma treatment). Both TEM and EDS analyses revealed,that the film was prepared along with suppression of metal cobalt nanoparticles' oxidization. Results showed that plasma processing provides new possibilities for processing of materials that are difficult to prepare under equilibrium conditions. (c) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.matlet.2006.08.044

Mn-Ce/ZSM5 as a new superior catalyst for NO reduction with NH3

Gabriela Carja, Yoshikazu Kameshima, Kiyoshi Okada, Changalla D. Madhusoodana

APPLIED CATALYSIS B-ENVIRONMENTAL 73 ( 1-2 ) 60 - 64 2007年4月

記述言語：英語出版者・発行元：ELSEVIER SCIENCE BV

Mn-Ce/ZSM-5 catalyst prepared in an aqueous phase at 423 K exhibits a broad temperature window (517-823 K) for high NO conversions (75-100%) in the process of selective catalytic reduction (SCR) by NH3 even in the presence of H2O and SO2. Both the zeolite matrix and the over-exchanged amounts of manganese and cerium contribute to obtain a complex structure that owns microporous-mesoporous characteristics and specific surface properties. (c) 2006 Elsevier B.V. All rights reserved.

DOI： 10.1016/j.apcatb.2006.06.003

P22.チタニア/スメクタイト複合体の細孔制御とその吸着特性(ポスターセッション,第50回粘土科学討論会発表論文抄録)

亀島欣一, 井川史彦, 中島章, 岡田清

粘土科学 46 ( 1 ) 86 - 86 2007年2月

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