مراد وهبه بروفيسور وأستاذ الفلسفة في جامعة عين شمس وعضو في مجموعة من الأكاديميات والمنظمات الدولية المرموقة كما أنه المؤسس ورئيس الجمعية الدولية لابن رشد والتنوير العام 1994 م. واسمه مذكور في موسوعة الشخصيات العالمية حيث يعتبر من بين ال500 شخصية الأكثر شهرة في العالم.
هو مراد وهبه جبران ولد في 13 أكتوبر 1926 م. في مدينة أسيوط في مصر. درس الفلسفة في جامعات القاهرة وعين شمس، ونال الدكتوراة من جامعة الأسكندرية.
Electro-Thermal and Semiconductivity Behaviour of Natural Sintered Complex Ca...Al Baha University
The polymetal (Zn, Pb, Fe, Ca, Mg, Cd, Ba, Ni, Ti, and SiO2) complex Umm-Gheig carbonate ore is subjected to sintering treatment at 573, 773, 973 and 1273 K respectively for four hours. Chemical, spectral, X-ray and differential thermal analyses are applied for the native ore as well as for the samples preheated and sintered. The I-V characteristics, bulk density (Db), percent shrinkage (%S), activation energy (Ea) and energy gap (Eg) are established for the sintered ore. The electrical conductivity (), thermal conductivity (K) and thermoelectric power coefficient () have been investigated as a function of applied temperature for the sintered ore materials. The electrical and thermal measurements show that the sintered ore has semiconductivity behaviour with temperature. The electrical conduction is mainly achieved by electrons or n-type. As the sintering temperature (Ts) increases the conduction of the ore is also increased owning to the recombination process takes place between the electrons and holes. Electrons hopping between Fe2+ and Fe3+ are the main charge carriers. The formation of Fe3O4 at high sintering temperature acts as an active mineralizer, thus inducing an increased degree of crystallinity and the more ordered crystal structure is produced.
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