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JaLCDOI 10.18926/21158
タイトル(別表記) Experimental study of sulfur isotope exchange between S0(4)(2-) and H(2)S (aqueous) at 400℃ and 1000 bars water pressure
フルテキストURL pitsr_050_001_015.pdf
著者 鎌田 恵美| 酒井 均| 木島 宣明|
抄録 Experimental procedures used in this study are the same as those developed by Sakai and Dickson (1978). 0.005 M Na(2)S(2)O(3) solutions were heated to 400℃ under 1000 bar water pressure in a gold bag of Dickson gold-bag equipment (Fig. 1). At an elevated temperature Na(2)S(2)O(3) quickly and completely decomposed into 1:1 mixture of SO(4)(2-) and H(2)S (eq. (1)) and subsequent isotope exchange (eq. (2)) was monitored by consecutively withdrawing aliquots of solution for chemical and isotopic analyses at desired time intervals. For the preparation of SO(2) for isotope analyses, 2 to 5 mg BaSO(4) was thoroughly mixed with silica glass powder of 10 times the BaSO(4) in weight and heated to 1400℃ or so in sealed, evacuated silica glass tubings (see Fig. 2 and equation (4)). The technique is a modification of Holt and Engelkemeir (1971). The (18)O/(16)O ratios of SO(2) thus formed stayed constant by exchange with silica glass powder (Fig. 3). Numerical data of the three runs performed in this study are summarized in Tables 1 to 3. In runs 2 and 3, a small aliquot of (34)S- enriched H(2)SO(4) was added into the starting solution and thus equilibrium was approached from above the quilibrium value (see Fig. 4). When isotope exchange occurs between two molecules, X and Y, the reaction rate, r, is related to the extent of exchange, F, at given time, t, by equation (17), where X and Y indicate concentrations of given species, α(e), α(o) and α denote the fractionation factor at equilibrium, at time t=0 and at an arbitrary time t, and F = (α - α(o))/(α(e) - α(0)) or the extent of isotope exchange. Assuming the exchange rate is of the first order with respect to both X and Y and to the β'th power of hydrogen ion activity, a(H)(+), eq. (17) reduces to eq. (19), where k(1) denotes the rate constant. If X, Y and pH of solution stayed constant during the run, the half-time, t(1/2), of the exchange reaction can be obtained graphically as shown in Fig. 5. The t(1/2) for runs 1, 2, and 3 are determined to be 5.8, 5.5 and 6.1 hrs, respectively. Introducing F=0.5 and t=t(1/2) into eq. (19), we obtain eq. (20) which is graphically shown in Fig. 6 using the data by the present work and those by Sakai and Dickson(1978). The numerical values of log k(1) + 0.16 may be obtained by extrapolating the lines to pH=0 and, from these values, the rate constant, k(1) , may be calculated for temperatures of 300° and 400℃. From these two values of k(1) and from the Arrhenius plot, the activation energy of the exchange reaction was calculated to be 22 kcal/mole, a much smaller value than 55 kcal/mole obtained by Igumnov (1977). The value of β is found to be 0.29 at 300℃ and 0.075 at 400℃, although the physico-chemical nature of β is not clear to the present authors. Using these values, eq. (24), where C is a constant, is derived which would enable us to calculate the t(1/2) of any system of known ΣS and pH. However, as we do not know yet how β varies with different systems, eq. (24) is applicable only to limited systems in which temperature, total sulfur contents and pH are similar to those of the present study. Fig. 7 illustrates how t(1/2) varies with pH and total sulfur content at 300° and 400℃ and predicts t(1/2) for some solutions obtainable by hydrothermal reactions of seawater with various igneous rocks. The average equilibrium fractionation factor at 400℃ obtained by this study is 1.0153, in good accord with 1.0151 given by Igumnov et al. (1977). Theoretical fractionation factors between SO(4)(2-) and H(2)S have been calculated by Sakai (1968) , who gives too high values compared to the experimental data obtained by this and other researchers (Fig. 9). In the present study, the reduced partition function ratio (R.P.F.R.) of SO(4)(2-) was recalculated using two sets of the vibrational frequencies of SO(4)(2-) (shown in Table 5) and the valence force fields of Heath and Linnett (1947), which reproduces the observed frequencies of SO(4)(2-) better than Urey-Bradley force field used by Sakai (1968). The results of new calculation are shown in Table 6. This table also includes the R.P.F.R. of H(2)S which was calculated by Thode et al. (1971). Using these new R.P.F.R. of SO(4)(2-) and H(2)S, the fractionation factors between SO(4)(2-) and H(2)S were calculated and are listed in the last column of Table 6 and plotted in Fig. 9. Fig. 9 indicates that the new calculation gives values more shifted from the experimental values than before. The major sulfate ions in our solution at 300° and 400℃ exist as NaSO(4)(-) (Sakai and Dickson, 1978; see also Table 4 of this paper) and, therefore, the measured fractionation factors are those between NaSO(4)(-) and H(2)S. The discrepancy between the theory and experiments may, at least, be partially explained by this fact, although other more important reasons, which are not known to us at the moment, may also exist.
出版物タイトル 岡山大学温泉研究所報告
発行日 1980-03-25
50巻
開始ページ 1
終了ページ 15
ISSN 0369-7142
言語 日本語
論文のバージョン publisher
NAID 120002310990
JaLCDOI 10.18926/fest/19742
フルテキストURL 004_147_158.pdf
著者 陳 丹平| 渡辺 智大| 三浦 嘉也| 難波 徳郎|
抄録 Photo-induced phenomena such as photoconductive and photovoltaic effects were investigated for the glasses in CdO-Bi(2)O(3)-Al(2)O(3) system. Photoconductive effect was characterized by a slow decay of photocurrent (persitent photoconductivity). The decay rate decreased with increasing CdO content and decreasing Bi(2)O(3) content. Photovoltage was very small at room temperature but increased to an obvious value on heating. The photoconductivity and photovoltage were increased with CdO content and enhanced by heat treatment in air. The valence band spectra of X-ray photoelectron spectroscopy showed that the hybridization of Cd 4d and O 2p orbitals increases with decreasing Bi(2)O(3) content and increasing CdO content in the glasses. As the results maximum tends to flat. This type of band structure inhibits the rapid recombination of electrons and holes. The persistent photoconductivity of the glasses may be attributed to deep energy level of DX centers. Deep energy levels of the glasses are able to prevent the recombination because they have a repulsive barrier for both electron emission and capture.
キーワード Photoconductivity Photovoltage Persistent photoconductivity CdO-Bi(2)O(3)-Al(2)O(3) glasses Electronic state
出版物タイトル 岡山大学環境理工学部研究報告
発行日 1999-02-26
4巻
1号
開始ページ 147
終了ページ 158
ISSN 1341-9099
言語 英語
論文のバージョン publisher
NAID 120002309190
JaLCDOI 10.18926/19596
フルテキストURL Mem_Fac_Eng_OU_31_2_45.pdf
著者 尾坂 明義| Kobayashi Keizo| 早川 聡| 大槻 主税|
抄録 The thermal expansion coefficient of some bioactive glasses in the system CaO-SiO(2)-B(2)O(3) were adjusted to be similar to that of titanium by controlling the composition. A glass of composition 45CaO・30SiO(2)・25B(2)O(3) was selected among those as the enameling glass. A slurry was prepared by mixing the glass powder and ethanal to be developed on titanium and heated at 740℃ for 30 min. Thus treated specimen was soaked in a simulated body fluid (Kokubo solutiion). FT-IR reflection and thin film X-ray diffraction analyses indicated apatite formation on the glass coating layer within 12 h of soaking in the fluid. Thus titanium could be provided with bioactivity due to the enameling.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1997-03-28
31巻
2号
開始ページ 45
終了ページ 51
ISSN 0475-0071
言語 英語
論文のバージョン publisher
NAID 120002309181
JaLCDOI 10.18926/19594
フルテキストURL Mem_Fac_Eng_OU_31_2_39.pdf
著者 Imayoshi Naoki| 早川 聡| 大槻 主税| 尾坂 明義|
抄録 Nb(2)O(5)-and Ta(2)O(5)-doped calcium si1icate glasses were soaked for various periods in a simulated body fluid(Kokubo solution) up to 30 days. Apatite formation ability of the surface of these glasses were investigated with thin-film X-ray diffraction and FT-IR reflection spectroscopy. The effects of these additive oxides on the bioactivity of CaO・SiO(2) based glass were discussed. A small amount of Nb(2)O(5) and Ta(2)O(5) suppressed the rate of silica hydrogel layer formation and the apatite formation on the surface of the glasses. The rate of the apatite nucleation on the surface of Nb(2)O(5)-doped calcium silicate glass was slower than that on the surface of Ta(2)O(5)-doped calcium silicate glass. It was concluded that the decrease in the apatite forming ability of calcium silicate glasses by these additive oxides is attributed to the suppression of formation of silica hydrogel layer which plays an important role in apatite nucleation.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1997-03-28
31巻
2号
開始ページ 39
終了ページ 44
ISSN 0475-0071
言語 英語
論文のバージョン publisher
NAID 120002309151
著者 石光 宏|
発行日 1979-08-30
出版物タイトル 岡山医学会雑誌
91巻
7-8号
資料タイプ 学術雑誌論文
JaLCDOI 10.18926/15824
フルテキストURL Mem_Sch_Eng_OU_17_1_97.pdf
著者 Oda Kiichi| Yoshio Tetsuo| O-oka Kazuo|
抄録 A series of ferroelectric glass-ceramics was elaborated by the controlled growth of Ba(1-x)Sr(x)TiO(3) crystal particles in the glass system 60[Ba(1-y)Sr(y)]TiO(3)-10Al(2)O(3)-30SiO(2)(0≦y≦0.2) in molar basis. Analysis of crystal phases by X-ray diffraction revealed that Sr content in Ba(1-x)Sr(x)TiO(3) increased with increasing content of SrO in glasses by its preferential transfer into the crystal phase, and the appropriate temperature for the crystal growth was 1100°C. Curie temperatures of glass -ceramics shifted to lower temperature with increasing SrO content in the crystal and comparatively high dielectric constant was obtained at room temperature for a glass-ceramics with y=0.2. Frequency dependences of dielectric constant and loss tangent were examined in the frequency range from 1 K to 1 M Hz.
出版物タイトル Memoirs of the School of Engineering, Okayama University
発行日 1983-02-25
17巻
1号
開始ページ 97
終了ページ 105
ISSN 0475-0071
言語 英語
論文のバージョン publisher
NAID 120002307890
JaLCDOI 10.18926/15787
フルテキストURL Mem_Sch_Eng_OU_19_1_45.pdf
著者 Oda Kiichi| Yoshio Tetsuo| O-oka Kazuo|
抄録 Succeeding to 60(Ba,Sr)TiO(3)-10A1(2)O(3)-30SiO(2)glassceramics reported in our previous paper, another type of ferroelectric glass-ceramics was elaborated by the controlled growth of Ba(l-x)Ca(x)TiO(3) crystal particles in the glass system 60 (Ba(l-y)Ca(y)) TiO(3)-10Al(2)O(3)-30SiO(2) (0.0
出版物タイトル Memoirs of the School of Engineering, Okayama University
発行日 1984-11-26
19巻
1号
開始ページ 45
終了ページ 51
ISSN 0475-0071
言語 英語
論文のバージョン publisher
NAID 120002307972
JaLCDOI 10.18926/15639
フルテキストURL Mem_Sch_Eng_OU_6_47.pdf
著者 Takahashi Katsuaki| Goto Yasumasa|
抄録 The glass forming limit by substitution of CdS for CdO in a CdO-B(2)0(3) glass was determined by chemical analysis. When x CdS-(60-x)CdO-40B(2)0(3) nominal mixtures in weight ratio were heated at 1100°C in flowing nitrogen gas for 1/2 hour, about 40~50% of mixed CdS and 10-15% of the mixed CdS were evaporated. The limit of nominal composition for glass forming was 10CdS-50CdO-40B(2)0(3) and the corresponding virtual composition after the above heat treatment was found to be 4.9CdS-46.4CdO-48.7B(2)O(3). Further addition of CdS made the melt devitrefied with CdS precipitation. D.C. conductivity measurements revealed that the current density was not linear with respect to the applied voltage, but the resistivity ranged around 10(12)Ω・cm for 4.1CdS-48.8CdO-47.1B(2)O(3) (virtual composition) glass and around 10(11.5)Ω·cm for 4.9CdS-46.4CdO-48.7B(2)O(3) glass. These sulphur containing glasses did not show photoconduction, although CdS-precipitated materials showed slight photoconductivity when disposed in ultra violet radiation. Apparent dielectric constant and tan 8 were also measured as a function of frequency, revealing a moderate dispersion in the CdS-precipitated glasses.
出版物タイトル Memoirs of the School of Engineering, Okayama University
発行日 1971-09-01
6巻
1号
開始ページ 47
終了ページ 52
ISSN 0475-0071
言語 英語
論文のバージョン publisher
NAID 120002307147
JaLCDOI 10.18926/15486
フルテキストURL Mem_Fac_Eng_OU_25_1_23.pdf
著者 三浦 嘉也| 高田 潤| 尾坂 明義| 河村 利夫|
抄録 Zinc oxide films were prepared on silica glass substrates by the use of an r.f. activated reactive evaporation (ARE) method, and were examined by X-ray diffraction (XRD) and scanning electron micrograph (SEM). XRD measurements indicate that the films were c-axis oriented and that an r.f. plasma of Zn and O was necessary for the ZnO film deposition. Substrate temperature, oxygen gas pressure, evaporation rate, r.f. power and inlet position of oxygen gas effect the c-axis orientation, the growth rate and the microstructure of the films. Optimum conditions for a dense film with a fine texture of the surface and having good crystallinity were as follows: the substrate temperature;400℃, the evaporation rate;5.0(A)/s, the oxygen pressure;2.0x10(-4) Torr, the r.f. power;150 to 200W, and the oxygen gas inlet near the substrate. For the film prepared under the optimum conditions, the standard deviation σ of the rocking curve for the (002) diffraction was 1.9deg, smaller than that of the film prepared by using an r.f. sputtering method.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1990-12-14
25巻
1号
開始ページ 23
終了ページ 35
ISSN 0475-0071
言語 英語
論文のバージョン publisher
NAID 120002307600
JaLCDOI 10.18926/15474
フルテキストURL Mem_Fac_Eng_OU_24_1_53.pdf
著者 尾坂 明義| Takao Seiji| 小田 喜一| 高田 潤| 三浦 嘉也|
抄録 Electrical resistance and X-ray photoelectron depth profile analysis are studied for antimony doped tin oxide films developed on silica, alkali-free and sodalime slide glass substrates. The sodium ions diffused from the substrates to the films prevented the crystal growth of rutile type tin oxide in the film, resulting in the high electrical resistance. A diffusion layer has been detected for each film with diffuse profiles of multi valent cations (Sn, Si or Ca) at the interface of the tin oxide film and substrate. A greater amount of sodium atoms have been detected in the film developed on the soda-lime glass while almost no sodium atoms have been found in those on the other substrates. This can be explained by the diffusion of the sodium ions in the substrate due to a drastic hydronium-sodium exchange mechanism under highly acidic conditions during the dipping and drying processes.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1989-11-29
24巻
1号
開始ページ 53
終了ページ 61
ISSN 0475-0071
言語 英語
論文のバージョン publisher
NAID 120002307279
JaLCDOI 10.18926/15428
フルテキストURL Mem_Fac_Eng_OU_29_2_83.pdf
著者 都留 寛治| Nishiyama Chikako| 大槻 主税| 尾坂 明義|
抄録 One of the CaO,SiO(2)-based bioactive glasses(5OCaO・ 5OSiO (2) in mol%) were soaked for various periods in a simulated body fluid(SBF) with or without containing alcohols such as methanol, ethanol, and 1-propanol. Effect of the alcohols was investigated on the apatite formation on the glass surface with thin-film X-ray diffraction, FT-IR reflection spectroscopy and scanning electron microscopy. Under the presence of alcohols up to 0.1mol/l in the SBF an apatite layer was formed on the glass, while it consisted of crystallites similar in morphology but larger in size than that found for the SBF without the alcohols. It was concluded that the alcohols little influenced the the apatite forming ability of the CaO,SiO(2)-based glasses.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1995-03-27
29巻
2号
開始ページ 83
終了ページ 88
ISSN 0475-0071
言語 英語
論文のバージョン publisher
NAID 120002307301
JaLCDOI 10.18926/15426
フルテキストURL Mem_Fac_Eng_OU_29_2_77.pdf
著者 都留 寛治| Nishiyama Chikako| 大槻 主税| 尾坂 明義|
抄録 Poly(methyl methacrylate) substrates were immersed in suspensions containing bioactive 50CaO・50SiO(2) (mol%) glass particles (45 μm in diameter) and a 6:4 (volume fraction) mixture of ethanol and THF, and an ultrasonic energy was applied to the system. A layer of glass particles was implanted and covered more than 50% of the substrate surface. Thin film X-ray diffraction patterns and FT-IR reflection spectra indicated deposition of apatite on the glass-implanted substrates after they were soaked for 12 h in a simulated body fluid similar in apatite-deposition ability to the human blood plasma. Flake-like apatite crystallites formed on the substrate soaked in SBF for 3 days.
出版物タイトル Memoirs of the Faculty of Engineering, Okayama University
発行日 1995-03-27
29巻
2号
開始ページ 77
終了ページ 81
ISSN 0475-0071
言語 英語
論文のバージョン publisher
NAID 120002307332
著者 高場 成治|
発行日 1994-10
出版物タイトル 岡山医学会雑誌
106巻
9-10号
資料タイプ 学術雑誌論文
JaLCDOI 10.18926/fest/11614
タイトル(別表記) Preparation and Properties of ZnO Transparent Conductive Thin Films by Activated Reactive Evaporation Method
フルテキストURL 002_121_129.pdf
著者 藤原 貴| 藤井 達生| 難波 徳郎| 高田 潤| 三浦 嘉也|
抄録 Zinc oxide films were prepared on silica glass substrates by the use of an r.f. activated reactive evaporation (ARE) method, and were examined by X-ray diffraction (XRD) and scanning electron microscope (SEM). The electrical conductivity of the films and the doping effect of Al ions were also investigated. XRD measurements indicate that the films were c-axis oriented and that an r.f. plasma of Zn and O was necessary for the ZnO film deposition. Substrate temperature, oxygen gas pressure, evaporation rate, r.f. power and Al doping amount affect the c-axis orientation, the growth rate, the microstructure of the films and electrical conductivity. Optimum conditions with a fine texture of the surface and having good ctystallinity as well as good conductivity (≒10(-4)Ω・cm) were as follows : the substrate temperature; 200℃, the total evaporation rate; 1.0Å/s, the oxygen pressure; 2.0×10(-4) Torr, the r.f. power; 250W and the Al evaporation rare ratio; 2~6%. The films with 1.0×10(-3)Ω・cm were prepared at 50℃ for the substrate temperature.
キーワード ZnO film Al doped ZnO transparent conductive film r.f. activated reactive evaporation method
出版物タイトル 岡山大学環境理工学部研究報告
発行日 1997-01-10
2巻
1号
開始ページ 121
終了ページ 129
ISSN 1341-9099
言語 日本語
論文のバージョン publisher
NAID 120002313550
JaLCDOI 10.18926/fest/11541
タイトル(別表記) Upconversion property and light scattering in Tm(3+)-doped glass-ceramics
フルテキストURL 007_119_125.pdf
著者 三浦 嘉也| 丁 勇| 村田 隆| 姫井 裕助| 難波 徳郎|
抄録 Glass-ceramics containing Pb(x)Cd(1-x)F(2) microcrystallites were prepared through heat treatment of Tm(3+)/Yb(3+)doped SiO(2)-Al(2)O(3)-PbF(2) glasses. The crystallite size was controlled by varying the heat-treatment time. By changing glass composition, two types of strong optical scattering, Rayleigh and Mie scattering modes were observed for the glass ceramics. In the case of Rayleigh scattering, the scattering region expanded to the long-wavelength side with increasing the heat-treatment time. On the other hand, in the case of Mie scattering, the region were hardly dependent on wavelength, and visible light was widely scattered. It was argued that the different scattering phenomena were caused by the different size of the crystallites or their morphogical texture. Furthermore, the glass-ceramics with strong optical scattering showed higher upconversion fluorescence intensity than the matrix glass. The mechanisms for the enhanced upconversion due to the scattering were discussed.
キーワード Optical scattering Glass-ceramics Oxyfluoride glass Microcrystallite Upconversion fluorescence
出版物タイトル 岡山大学環境理工学部研究報告
発行日 2002-03-22
7巻
1号
開始ページ 119
終了ページ 125
ISSN 1341-9099
言語 日本語
論文のバージョン publisher
NAID 120002313480
JaLCDOI 10.18926/fest/11538
タイトル(別表記) Effects of ultrasonic treatment on the preparation of transparent glass-ceramic phosphor
フルテキストURL 007_113_118.pdf
著者 井上 輝英| 中島 瑞穂| 難波 徳郎| 三浦 嘉也|
抄録 The effects of ultrasonic surface treatment (UST) on the crystallization behavior and optical emission properties were investigated for the transparent glass-ceramics prepared from calcium aluminosilicate glasses co-doped with Eu(2+), Nd(3+). The glass-ceramics A were prepared by sintering a glass 45CaO・45Al(2)O(3)・10SiO(2) (mol%) containing 0.5Eu(2)O(3)+1Nd(2)O(3) under a 2% H(2)+98% Ar reducing atmosphere. In the glass-ceramics A, three crystalline phases, CaAl(2)O(4) (CA), CaAl(4)O(7) (CA2) and Ca(2)Al(2)SiO(7) (CAS) were commonly confirmed by X-ray diffraction. No drastic change in the amount of the precipitated crystalline phases was observed even in the case using UST of CA powders. It was suggested that the optical emission properties of the glass-ceramics A was responsible for the CA2 crystals. The glass-ceramics B were also prepared from a 51CaO・42Al(2)O(3)・7SiO(2) glass. The CA crystals were separately precipitated in the glass-ceramics B. In particular, a large amount of CA was successfully produced by stirring the UST suspension to prevent the sedimentation of the UST particles. The glass-ceramic B so-prepared showed strong photoluminescence but weak phosphorescence compared with other glass-ceramics B, indicating that the photoluminescence and phosphorescence were originated in different electron-trapping levels. The amount of the trap levels associated with the long lasting phosphorescence, such as oxygen vacancies, was probably small in the glass-ceramic B prepared with the stirring UST.
キーワード ultrasonic surface treatment (UST) surface crystallization glass-ceramics long lasting phosphorescence calcium aluminosilicate glass
出版物タイトル 岡山大学環境理工学部研究報告
発行日 2002-03-22
7巻
1号
開始ページ 113
終了ページ 118
ISSN 1341-9099
言語 日本語
論文のバージョン publisher
NAID 120002313433
著者 吉田 敏治|
発行日 1976
出版物タイトル 岡山大学農学部学術報告
48巻
1号
資料タイプ 紀要論文
著者 須藤 浩| 内田 仙二|
発行日 1958
出版物タイトル 岡山大学農学部学術報告
12巻
1号
資料タイプ 紀要論文