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        검색결과 70

        21.
        2011.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study focused on the synthesis of Bi-Te-Se-based powder by an oxide-reduction process, and analysis of the thermoelectric properties of the synthesized powder. The phase structure, chemical composition, and morphology of the synthesized powder were analyzed by XRD, EPMA and SEM. The synthesized powder was sintered by spark plasma sintering. The thermoelectric properties of the sintered body were evaluated by measuring its Seebeck coefficient, electrical resistivity, and thermal conductivity. powder was synthesized from a mixture of , , and powders by mechanical milling, calcination, and reduction. The sintered body of the synthesized powder exhibited n-type thermoelectric characteristics. The thermoelectric properties of the sintered bodies depend on the reduction temperature. The Seebeck coefficient and electrical resistivity of the sintered body were increased with increasing reduction temperature. The sintered body of the powder synthesized at showed about 0.5 of the figure of merit (ZT) at room temperature.
        4,000원
        22.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The p-type thermoelectric compounds of based doped with 3wt% Te were fabricated by a combination of rapid solidification and spark plasma sintering (SPS) process. The effect of holding time during spark plasma sintering (SPS) on the microstructure and thermoelectric properties were investigated using scanning electron microscope (SEM), X-ray diffraction (XRD) and thermoelectric properties. The powders as solidified consisted of homogeneous thermoelectric phases. The thermoelectric figure of merit measured to be maximum () at the SPS temperature of .
        4,000원
        23.
        2010.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study focused on the synthesis of Bi-Sb-Te-based thermoelectric powder by an oxidereduction process. The phase structure, particle size of the synthesized powders were analyzed using XRD and SEM. The synthesized powder was sintered by the spark plasma sintering method. The thermoelectric property of the sintered body was evaluated by measuring the Seebeck coefficient and specific electric resistivity. The powder had been synthesized by a combination of mechanical milling, calcination and reduction processes using mixture of , and powders. The sintered body of the powder synthesized by an oxide-reduction process showed p-type thermoelectric characteristics, even though it had lower thermoelectric properties than the sintered body of the thermoelectric powder synthesized by the conventional melting-crushing method.
        4,000원
        24.
        2010.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbon-nanotube-embedded bismuth telluride (CNT/) matrix composites were fabricated by a powder metallurgy process. Composite powders, whereby 5 vol.% of functionalized CNTs were homogeneously mixed with alloying powders, were successfully synthesized by using high-energy ball milling process. The powders were consolidated into bulk CNT/ composites by spark plasma sintering process at for 10 min. The fabricated composites showed the uniform mixing and homogeneous dispersion of CNTs in the matrix. Seebeck coefficient of CNT/ composites reveals that the composite has n-type semiconducting characteristics with values ranging to with increasing temperature. Furthermore, the significant reduction in thermal conductivity has been clearly observed in the composites. The results showed that CNT addition to thermoelectric materials could be useful method to obtain high thermoelectric performance.
        4,000원
        30.
        2008.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study focused on the synthesis of a bismuth-antimony-tellurium-based thermoelectric nanopowders using plasma arc discharge process. The chemical composition, phase structure, particle size of the synthesized powders under various synthesis conditions were analyzed using XRF, XRD and SEM. The powders as synthesized were sintered by the plasma activated sintering. The thermoelectric properties of sintered body were analyzed by measuring Seebeck coefficient, specific electric resistivity and thermal conductivity. The chemical composition of the synthesized Bi-Sb-Te-based powders approached that of the raw material with an increasing DC current of the are plasma. The synthesized Bi-Sb-Te-based powder consist of a mixed phase structure of the , and phases. This powder has homogeneous mixing state of two different particles in an average particle size; about 100nm and about 500nm. The figure of merit of the sintered body of the synthesized 18.75 wt.%Bi-24.68 wt.%Sb-56.57 wt.%Te nanopowder showed higher value than one of the sintered body of the mechanically milled 12.64 wt.%Bi-29.47 wt.%Sb-57.89 wt.%Te powder.
        4,000원
        33.
        2006.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study is to analyze the thermoelectric properties of thermoelectric materials fabricated by the mechanical grinding process. The powders were prepared by the combination of mechanical milling and reduction treating methods using simply crushed pre-alloyed powder. The mechanical milling was carried out using the tumbler-ball mill and planetary ball mill. The tumbler-ball milling had an effect on the carrier mobility rather than the carrier concentration, whereas, the latter on the carrier concentration. The specific electric resistivity and Seebeck coefficient decreased with increasing the reduction-heat-treatment time. The thermal conductivity continuously increased with increasing the reduction-heat-treatment time. The figure of merit of the sintered body prepared by the mechanical grinding process showed higher value than one of the sintered body of the simply crushed powder.
        4,000원
        34.
        2006.04 구독 인증기관·개인회원 무료
        Thermoelectric thick film was fabricated by screen printing process with using p-type Bi-Te-Sb powders. The powder was synthesized by melting, milling and sintering process and hydrogen reduced to enhance the thermoelectric property. The thick film of Bi-Te-Sb powder was fabricated by screen printing method and baked at the optimized conditions. The thermal conductivity, the electrical resistivity and Seeback coefficient of thick film were measured and the thermoelectric performance was analyzed in terms of film characteristics and its microstructure. Finally, the feasibility of thermoelectric thick film into micro cooling device on CPU chip was discussed in this study.
        35.
        2006.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A nation's correction level develops in direct proportion to the nation's level. But the correctional principle does not suit our actuality. Since revival, our nation's correctional organization has been falling behind the other administrative organ's result of developmental reorganization. Nowadays, correction business is greatly increasing day by day and a second offense never decreased. Therefore correction administrative business' professional and effectual promotion needs increasingly. But now our nation's correction bureau is existing as a domestic shape of the ministry of justice which only is a assistance organ of the minister of justice. As a result, it is appeared that the difficulty of command and control in perfect order, the subordination of prosecutor, and correction civil servant's depressing the morale of the troops and so on. This study till now shows these theoretical problems at various literature but actually there was not smoothly allusion that how is the correction civil servant's thought who is charging with the correction business. Accordingly, I grasped the actual conditions for the development of correction administrative to correction civil servants who work at correction facility in the whole land's 46 sites and I understood what is necessary for this. As a result for the development of correction administrative, I knew that the modernization of correction facility, the independence of correction office, and the increment of correction facility are immediate. If the development of correction administrative is not, a criminal's social comeback is difficult. So the damage returns again a good general citizens. Consequently, now theoretically or actually the independence of correction service is not optional but indispensable. Any society, from the shady spot where has to advance for the first time we can say being advanced.
        6,600원
        38.
        2005.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The p-type semiconductor thermoelectric materials were fabricated by melting, milling and sintering process and their thermoelectric properties were characterized. The compound materials were ball-milled with milling time and the powders were sintered by spark plasma sintering process. The ball milled powders had equiaxial shape and approedmately in size. The figure of meritz of sintered thermoelectric materials decreased with milling time because of lowered electrical resistivity. The thermoelectric properties of materials have been discussed in terms of electrical property with ball mill process.
        4,000원
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