Papers by Author: Iwao Katayama

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Authors: Iwao Katayama, Toshihiro Tanaka, Shin-ichi Akai, Kisao Yamazaki, Takamichi Iida
Abstract: Activity of tin in liquid Sn-Ag-Bi alloys was derived by EMF measurement of galvanic cell with fused salts electrolyte in the temperature range of 700 to 900K in the whole composition range. Activity of tin at 900K shows very small positive deviation from Raoult’s low for Sn-Bi alloys. Activity of ternary alloys was measured along three pseudo binary systems of Sn-(Ag,Bi) (where xAg/xBi =1/3,1/1 and 3/1). Its concentration dependence is very complex. From the iso-activity curves in the ternary system excess free energy of mixing is derived using Darken’s method for Gibbs-Duhem equation
Authors: Hiromi Yamashita, Yoshikatsu Nishida, Osamu Chiyoda, Hiroyuki Nose, Masaki Narisawa, Tesutaro Ohmichi, Iwao Katayama
Abstract: TiO2/SiC was prepared by oxidizing the TiC-SiC precursor obtained by carbothermic reduction process of TiO2-SiO2 binary oxide. An XRD analysis indicated the formation of the mixture of anatase and rutile phases of TiO2 crystalline after the oxidation of TiC-SiC sample. TiO2/SiC photocatalyst exhibited a higher photocatalytic reactivity than TiO2-SiO2 binary oxide prepared by the conventional sol-gel method. These results indicate the advantages of SiC nano powders as catalyst support of the TiO2 photocatalysts, and TiO2/SiC photocatalyst is effective for the degradation of organic compounds diluted in water.
Authors: Iwao Katayama, Yusuke Sendai, Dragana Zivkovic, Dragan Manasijević, Zivan Zivkovic, Hiromi Yamashita
Abstract: EMF of galvanic cell with zirconia –based solid electrolytes was measured to determine the activity of Ga in liquid Ga-Sb-Tl alloys between 946 and 1233 K along the tree pseudobinary lines of Ga-(Sb/Tl), (xSb/xTl = 1/3, 1/1 and 3/1) The cell used was: Ga,Ga2O3|(ZrO2)0.92(Y2O3) 0.08|Ga-Sb-Tl, Ga2O3. The activity of Ga (aGa ) was derived by :-3EF = RT ln aGa , where E is cell potential, F is Faraday’s constant, R is gas constant and T is cell temperature. The activity of Ga shows slight negative deviations from ideality in the section with positive deviation from ideality in the whole composition range. The activity of gallium shows slight negative deviations from Raoult’s law in the section with xSb/xTl = 3/1, moderately positive deviations in xSb/xTl =1/1 section and large positive deviations in xSb/xTl =1/3 section.
Authors: Dragana Živković, Iwao Katayama, Živan Živković, Dragan Manasijević
Abstract: The results of thermodynamic investigation of some liquid alloys in Ga-Sb-Bi-Sn system, obtained by calculation according to different thermodynamic predicting methods, are presented in this paper. The research was done based on the known experimentally obtained thermodynamic properties of related binary and ternary subsystems. Calculated data on a Ga-Sb-Bi-Sn system include thermodynamic properties for liquid alloys at temperature of 900K in chosen sections of investigated quarternary system with molar ratios of Sn:Sb:Bi = 6:3:1; 8:1:1 and 6:1:3.
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