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KMID : 1059519870310050400
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Journal of the Korean Chemical Society
1987 Volume.31 No. 5 p.400 ~ p.405
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The Effects of Substituent, Pressure and Temperature on the Dissociation Constants of Organic Acids. (6) Dissociation Constants of Some Amino Acids in Aqueous Solution
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Hwang Jung-Ui
Lee Woo-Bung
Chae Jong-Keun
Kim Hag-Sung
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Abstract
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The electrical conductivities of α-Fe2O3 containing 2.5 and 5.0mol% of cadmium were measured from 300 to 900℃ under oxygen pressures of 10-7 to 10-1 atmosphere. Plots of log σ vs. 103/T show the extrinsic conductivity at oxygen pressure higher than 5 × 10-2 atm. The transition points appear at about 550℃ and the activation energies are 1.34 eV for the intrinsic region and 0.50 eV for the extrinsic region on 5mol% Cd-doped α-Fe2O3. The extrinsic conductivity disappears at oxygen partial pressures lower than 5 × 10-2 atm, and the intrinsic conductivity predominates. The electrical conductivities decrease with increasing mol% of cadmium doped. The predominant defect of α-Fe2O3 doped with Cd is believed to be Fe2+ interstitial for the intrinsic, however, oxygen vacancy predominates for the extrinsic region. The electrical conduction mechanisms are proposed and the conduction band model is suggested for the extrinsic region.
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KEYWORD
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