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MAKOTO WATANABE, NAOKI ASAI, MAKOTO SAKURAI, MIOKO MAEDA
1998 Volume 8 Pages
1-6
Published: 1998
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Sodium hexaphosphate was made by hydrolyzing
cyclo-hexaphosphate in a 10M sodium hydroxide solution at -7°C, neutralizing the solution with hydrochloric acid, sampling a hexaphosphate solution by column separation, and then adding methanol to the hexaphosphate solution. Ammonium hexaphosphate was prepared by dissolving sodium hexaphosphate in water, removing sodium ions by passing the solution through a cation exchange resin, and then adding ammonia water and ethanol to the resulting solution. Alkaline earth hexaphosphates were made by dissolving the sodium hexaphosphate in water, adding alkaline earth chlorides to the solution, and aging it for 1h at 0°C with stirring. Sodium and alkaline earth hexaphosphates were amorphous and unstable. They decomposed to phosphates with shorter chain lengths at room temperature. Ammonium hexaphosphate was crystalline and stable at room temperature.
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Y. Moriyoshi, Y. Chiba, M. Koide, E. Ishibe, J. Fukawa, H. Monma, T. I ...
1998 Volume 8 Pages
7-10
Published: 1998
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Porous hydroxyapatite(HA) prepared on the surface of mortar by a wet process at 40-100°C and pH 10 was characterized with a scanning electron microscope(SEM) and by energy dispersed analysis of X-ray(EDX) and X-ray diffractometry. The appropriate conditions of HA preparation and the formation mechanisms of the HA were briefly discussed.
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TATEOKI IIZUKA, AKIYO NODUMA
1998 Volume 8 Pages
11-16
Published: 1998
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The whisker-like hydroxyapatite (HAp) crystals have been synthesized by the precipitation reaction of the buffer solution containing calcium acetate and phosphoric acid. The growth mechanism of the whisker-like HAp prepared at 90°C for various heating time was studied by analyzing the morphology, composition and structures of the precipitates. It was found that during the precipitation reaction, the whisker-like octacalcium phosphate (OCP) crystals formed at first from the dehydration reaction of brushite, and the structure then gradually converted from OCP to HAp as the heating time increased. The Ca/P atomic ratios of whisker-like HAp varied from 1.60 to 1.67 depending on the heating time.
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KIYOKO SAKAMOTO, ATSUSHI NAKAHIRA, MASAYUKI OKAZAKI, NOBUYUKI MATSUDA, ...
1998 Volume 8 Pages
17-21
Published: 1998
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The transformation of α-tricalcium phosphate (α-TCP) to hydroxyapatite (HAp) in organic media has been investigated. Hydrolysis of α-TCP in a series of aliphatic alcohols was carried out under the control of pH and the reaction temperature. The transformation rates and shape of HAp depended on aliphatic alcohols. The formation rates of HAp increased with increasing hydrophobicity of alcohols. The rates in 1-octanol and 1-hexanol were 5-times faster than that in the hydrophilic alcohols and were compatible to that without alcohols. The shape of HAp prepared in the hydrophobic alcohols were the needle-like particle (length; 1.0~3.5μm) and differed from HAp prepared in hydrophilic alcohols or without alcohol.
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SHIGERU SUGIYAMA, TOMOMI NAKANISHI, HIROMU HAYASHI, JOHN B. MOFFAT
1998 Volume 8 Pages
23-30
Published: 1998
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Four preparation procedures for barium hydroxyapatite have been compared. Of these only one produced high pure nonstoichiometric barium hydroxyapatite and can be recommended as facile preparation procedure.
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Tomohiro Umeda, Keishi Nishio, Yuichi Watanabe, Toshio Tsuchiya
1998 Volume 8 Pages
31-36
Published: 1998
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Hydroxyapatite (HAp: Ca
10(PO
4)
6(OH)
2 thin films having porous structure were prepared by sol-gel process with dip-coating using calcium acetate (Ca(CH
3COO)
2·H
2O) and triethylene phosphate.
In the present study, the surface of titanium metal was coated with a sodium-titanium oxide layer by sol-gel process treatment with alkali hydroxide solutions. HAp thin film prepared on modified titanium substrate was then obtained at 800°C (under transformation point of titanium metal) so at lower temperature than previous process. Peeling of HAp thin film was prevent by the formation of sodium-titanium oxide layer. Calcium oxide free HAp films were synthesized with acetate as a raw materials of calcium and rapid heating at 800°C for 1 hr. The films were chemically bonded to the substrate and had a porous structure which was expected to show a good bioactivity.
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MASATAKA OHGAKI, KIMIHIRO YAMASHITA
1998 Volume 8 Pages
37-42
Published: 1998
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The coatings of α-tricalcium phosphate (α-TCP) and hydroxyapatite (HAp) were carried out on titanium plates by a plasma spraying technique. The characterizations for the α-TCP and HAp coatings were done by X-ray diffraction analysis, SEM observation, X-ray fluorescence analysis. In the HAp coatings on titanium plate, amorphous-like layers were observed for the inside layers of coating near to the substrata, while crystalline layers were observed for the coating surface. In the α-TCP coatings, the inside layer of coating had the same crystallinity as the surface layer.
In vitro Cell proliferation tests of the coating layers indicated that both the α-TCP-and HAp-coatings on titanium plate had better biocompatibility than the titanium plate without coatings.
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MAMORU AIZAWA, TAMAKI SHIMIZU, KIYOSHI ITATANI, F. SCOTT HOWELL, AKIRA ...
1998 Volume 8 Pages
43-48
Published: 1998
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The porous hydroxyapatite (HAp) ceramics were fabricated using the fibrous HAp particles prepared by the homogeneous precipitation method. The silicone was induced into the open pores of porous HAp ceramics by a cold isostatic pressing; then this induced silicone was polymerized by heating at 150°C for 30min. The SEM observation showed that the silicone was present inside the porous HAp ceramics. The resulting HAp-silicone composites were elastically fractured rather than the porous HAp ceramics alone.
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S. SHIMABAYASHI, S. NISHINE, T. HINO, T. UNO
1998 Volume 8 Pages
49-54
Published: 1998
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Adsorption of hydroxypropylcellulose(HPC) on hydroxyapatite (HAP) in the presence of sodium dodecylsulfate (SDS) and its effect on zeta potential of the HAP in an aqueous phase were studied. Although the adsorption amount of HPC was low in the absence of SDS, it increased with a concentration of SDS by virtue of formation of the complex between them on the surface. Zeta potential of the HAP was negative(-14mV) in an aqueous solution of 0.9% NaCl. Its absolute value decreased with a concentration of HPC because the slipping plane moves to the outside of the particle with the adsorption amount of HPC. The zeta potential, on the contrary, became more negative with a concentration of SDS after its adsorption and formation of the surface complex with HPC.
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HIROYUKI SAWA, ATSUSHI TAKENAKA, MASAMI HASEGAWA, KAORU AOKI
1998 Volume 8 Pages
55-58
Published: 1998
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Removal and separation of lead(II) and cadmium(II) and those of chromium(III), nickel(II), and zinc(II) in aqueous solution were examined by use of hydroxyapatite (n-HAp) prepared from fish scales. These removal reactions proceeded quickly, and lead(II) and chromium(III) could be removed well. And the possibility of separating lead ion from cadmium ion in aqueous solution was confirmed. As the n-HAp can be supplied at a low price by using scales of fishery waste, it is expected to be available for practical use to remove and recover some toxic heavy metal ions from industrial waste.
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YOSHIYUKI KOJIMA, TOMONORI HAYASHI, TAMOTSU YASUE, YASUO ARAI
1998 Volume 8 Pages
59-63
Published: 1998
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The present study was made to investigate adsorption of bovine serum albumin (BSA) on hydroxyapatite (HAp) which was crystallized by dipping amorphous calcium phosphate (ACP) in Ringer solution having a composition similar to body fluid
in vivo. Characterization of products was determined by means of X-ray diffraction, ion chromatography and ultraviolet spectrophotometry. When ACP was dipped for 48 hours in Ringer solution, maximum amount of BSA adsorbed on HAp prepared by crystallizing ACP was 190mg/g. Adsorption velocity till reaching to maximum amount of BSA adsorbed on HAp was speeded up by increasing concentration of BSA. The equilibrium amount of BSA adsorbed on HAp was 1.2mg/m
2. When ACP was dipped in Ringer solution, the largest quantity of BSA could be adsorbed to HAp crystallized in a short time.
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TAKESHI TOYAMA, TAMOTSU YASUE, YASUO ARAI
1998 Volume 8 Pages
65-69
Published: 1998
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The principal component of bovine bone waste was low crystalline hydroxyapatite (HAp), which was more effective to substitution of phosphorus resources. The present work was investigated about mechanochemical synthesis of amorphous calcium phosphate (ACP) from bovine bone obtained by removing protein. The raw material was used HAp obtained by heating bovine bone at 800°C. A mixture of HAp and ammonium dihydrogenphosphate in the weight ratio of 8/1 (Ca/P atomic ratio = 1.50) was ground for 24 hours. The products were characterized by means of X-ray diffraction patterns, thermal analysis (TG- DTA), transmission electron microscopic (TEM) observation, chemical analysis measurements of BET specific surface area and density. The crystalline of the mixture was decreased with increasing grinding time and amorphous phase was formed after 10 minutes. Ca/P atomic ratio of the ground mixture with particle size of 200 nm was 1.48. As results of TG-DTA, ACP obtained by liquid phase synthesis had usually exothermic peak to crystallization from ACP into β-tricalcium phosphate (β-TCP) at 670°C. Also, the ground mixture was confirmed exothermic peak at 625°C.
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ZAHID AMJAD
1998 Volume 8 Pages
71-83
Published: 1998
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The crystal growth of dicalcium phosphate dihydrate (DCPD) from aqueous solution at sustained supersaturation has been investigated by a constant-composition technique. A variety of polymeric (i.e., fulvic acid, FA; tannic acid, TA; poly(acrylic acid), PAA) and non-polymeric compounds (i.e., salicylic acid, SA; and benzene hexacarboxylic acid, BHCA) have been examined for their effects as DCPD growth inhibitors. The results indicate that crystal growth of DCPD is strongly influenced by changing the functional group, ionic charge, and the concentration of inhibitor. The retarding effect of these inhibitors is discussed in relation to Langmuir adsorption model. The ranking, in terms of decreasing effectiveness on DCPD crystal growth, of various natural and synthetic inhibitors studied is PAA, BHCA, FA, and TA. Salicylic acid, under the experimental conditions employed, did not exhibit any inhibitory activity.
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YASUO HIKICHI, TOSHITAKA OTA, TOMOTOSHI HATTORI
1998 Volume 8 Pages
85-88
Published: 1998
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Xenotime-type RPO
4 (R=Ho or Tm) powder was dry-pressed to disks and bars. The disks and bars could be sintered to the relative density ≥ 98% in air without cracking at 1400°C for R=Tm or 1550°C for R=Ho, depending on the grain size. Young's modulus, Poisson's ratio, linear thermal expansion coefficient (20-1000°C) and bending strength (20°C) of sintered xenotime-type RPO
4 ceramics were 170 GPa, 0.299, 6.2×10
-6/°C and 93 ± 25 MPa for R=Ho; 162 GPa, 0.303, 6.0×10
-6/°C and 131 ± 37 MPa for R=Tm, respectively.
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HIROKAZU NAKAYAMA, AKI HAYASHI, MITSUTOMO TSUHAKO, TARO EGUCHI, NOBUO ...
1998 Volume 8 Pages
89-94
Published: 1998
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In order to characterize various forms of layered cerium phosphates,
31P MAS and CP/MAS NMR spectra were measured in the solid state. Two peaks around -10 and -30 ppm suggest them to be γ-type structure with the non-stoichiometric amount of hydration waters.
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MASAMI NANZYO, SHIN-ICHI YAMASAKI
1998 Volume 8 Pages
95-100
Published: 1998
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The occurrence of apatite was confirmed in three unweathered andesite and rhyolite tephras from the northern part of Japan. The apatite mineral was identified using a scanning electron microscope (SEM) and energy dispersive X-ray analysis (EDX). The apatite mostly occurred as inclusions in the heavy minerals. The apatite was soluble in an acidic soil testing solution (Truog method) to determine plant-available phosphorus (P) in the soil.
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HIROYUKI NARIAI, SHINJI SHIBAMOTO, HIDESHI MAKI, ITARU MOTOOKA
1998 Volume 8 Pages
101-106
Published: 1998
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Influence of mechanochemical effects on the formation and property of MNiPO
4 (M: alkaline metal) was examined by using XRD, DTA-TG, UV-VIS, and so on. Starting mixtures were ground with grinding mill. The samples were calcined to synthesize MNiPO
4 compounds. Amorphous phase was observed in all ground samples, although mechanochemical reaction occurred partly in some ground samples. When the ground samples were heated, these crystallization temperatures were lower than those of unground samples. The intensities of XRD peaks of MNiP
O 4 produced from ground samples were stronger than those of unground samples, too. From the result of UV-VIS, mechanochemical treatment was more effective in the case of synthesizing MNiPO
4 as pigments.
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ATSUSHI TAKENAKA, HIROYUKI SAWA, MANABU HIRATA, AKIHIDE YAMAMOTO, ITAR ...
1998 Volume 8 Pages
107-112
Published: 1998
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Mixtures of sodium dihydrogenphosphate and urea were heated in a stream of nitrogen gas to prepare inorganic phosphates with phosphorus-nitrogen bonds. Although they were not produced, addition of a large amount of urea was effective for the formation of sodium cyclo-triphosphate. Lithium carbonate-ammonium dihydrogenphosphate-urea mixtures were also heated in order to prepare lithium cyclo-hexaphosphate. The cyclo-hexaphosphate was hardly obtained, while lithium cyclo-tetraphosphate produced.
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HIROYUKI NARIAI, TETSUYA TATSUKAWA, HIDESHI MAKI, ITARU MOTOOKA
1998 Volume 8 Pages
113-118
Published: 1998
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Lead cyclo-triphosphate (P
3m) was synthesized and its thermal behavior was investigated by DTA-TG, XRD, and HPLC-FIA. It hydrolyzed to various short-chain lead phosphates at about 200°C, and they condensed to long-chain lead polyphosphate through lead
cyclo-tetraphosphate (P
4m) and
cyclo-octaphosphate (P
8m), or directly condensed to long-chain lead polyphosphate.
For the purpose of increasing the yield of P
8m, the thermal change of P
3m at various heating rates was investigated. P
8m was obtained in a 90% yield at heating rate of 3°C/min, while its yield at 20°C/min was about 30%.
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HIROYUKI NARIAI, HIRONORI TANIGUCHI, HIDESHI MAKI, ITARU MOTOOKA
1998 Volume 8 Pages
119-124
Published: 1998
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Cyclo-tetraphosphates with heavy metals which are known to have high catalytic activities were synthesized and investigated on their catalytic activities for the dehydration of 2-propanol. Specific surface area, acid strength, and acidity of various
cyclo-tetraphosphates were also measured and the correlation between catalytic activities and physicochemical properties were discussed.
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NORIYASU OKAZAKI, HIDENOBU ITOH, AKIO TADA
1998 Volume 8 Pages
125-130
Published: 1998
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AlPO
4, YPO
4, and BPO
4 were ground, and their physical properties and catalytic activities for the isomerization and/or oligomerization of
n-olefins were investigated. It was found that the activity of BPO
4 for the oligomerization was enhanced by grinding, while those of AlPO
4 and YPO
4 for the isomerization were suppressed. These changes were mainly related to the increase (in the case of BPO
4) or decrease (AlPO
4 and YPO
4) in the specific surface areas.
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Noriyasu OKAZAKI, Yoshikazu SHIINA, Yoshitaka YAMAMOTO, Akio TADA
1998 Volume 8 Pages
131-136
Published: 1998
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Among various phosphates tested, only BPO
4 was active for the oligomerization of
n-olefins. The preadsorption of ammonia on BPO
4 caused the marked decrease in the activity, suggesting that the active sites are the acid sites. Acidic properties were observed on all the phosphates used. BPO
4 possessed both Lewis- and Brønsted-acid sites, but the other phosphates except for Ti(HPO
4)
2·H
2O had almost only Lewis-acid sites, suggesting that the acid sites which are essential for the oligomerization are of Brønsted type.
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NORIYASU OKAZAKI, MITURU OISHI, AKIO TADA
1998 Volume 8 Pages
137-142
Published: 1998
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Crystalline bis-(monohydrogenorthophosphate) of titanium (α-TiP) and titanium pyrophosphate were prepared and their catalytic activities for 1-butene isomerization were investigated. The activity of α-TiP strongly depends on the evacuation temperature; it reached a maximum at 600°C. Though titanium pyrophosphate showed negligibly low activity before grinding, it showed substantial activity after grinding. Ground titanium pyrophosphate exhibited similar evacuation-temperature dependence of the activity to that for α-TiP.
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JUNKO ICHIHARA, SHUNRO YAMAGUCHI
1998 Volume 8 Pages
143-146
Published: 1998
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Catalytic activities of a series of Keggin-type heteropoly acids with structural similarity were examined based on the H
2O
2-oxidation reaction of 1-octen-3-ol. Structural changes in the heteropoly acids reflected the selectivities of the oxidation reaction. Thus, we found that H
2O
2-oxidation reaction of 1-octen-3-ol is a useful probe reaction for comparison of the catalytic activities of a series of heteropoly acids with partial modification.
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A. LEDOUX, J. Y. DAUPHIN, G. MESMAQUE, P. VAST
1998 Volume 8 Pages
147-153
Published: 1998
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Polyphosphates glasses may be used as a sintering aid for alumina based ceramics composites. The knowledge of the mechanism of the wettability of alumina by melted polyphosphate glasses is an fundamental point for the sinterring control. We show that the wettability on inactive alumina is obtained in two stages. The first stage consists in a reaction between alumina and phosphorus pentoxyde exhaust from the melted glass bulk. The formation of a thin layer of aluminium phosphate permits, in a second stage, the wettability of the alumina. So the control of wettability needs to adapt the glasses formula to the phosphorus pentoxyde exhaust power in melted phase.
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