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        검색결과 4

        1.
        2006.09 구독 인증기관·개인회원 무료
        W-Cu alloy was very useful material for a heat sink, high electric contact and EDM electrode. Powder injection molding (PIM) is the optimum manufacturing technology to provide W-Cu components with low-cost and high-volume. We used various compositions of tungsten coated copper powders (W-Cu with 10 to 80 wt-% of copper) to manufacture W-Cu components by PIM. The optimum mixing, injection molding, debinding and sintering conditions to provide the high performance W-Cu components were investigated. The thermal and mechanical properties of W-Cu parts by PIM were measured. Finally, we can verify the high performance of W-Cu components by PIM with the tungsten coated copper.
        2.
        2006.04 구독 인증기관·개인회원 무료
        Chip breaker of cutting tool is an important feature to enhance cutting performance. Powder injection molding process was used to produce a triangular-shape cermet grooving insert which has three chip breakers. Attrition milled cermet powders were mixed with wax-based binder system in continuous twin screw extruder. Three-plate injection mold with slide cores was used to produce injection-molded parts. After molding, solvent and thermal debinding was carried out. Sintering was conducted in a batch furnace with a graphite heater. The sintered parts satisfy the requirements of dimensional tolerances and material properties.
        3.
        2006.04 구독 인증기관·개인회원 무료
        Thermal management technology is a critical element in all new chip generations, caused by a power multiplication combined with a size reduction. A heat sink, mounted on a base plate, requires the use of special materials possessing both high thermal conductivity (TC) and a coefficient of thermal expansion (CTE) that matches semiconductor materials as well as certain packaging ceramics. In this study, nano tungsten coated copper powder has been developed with a wide range of compositions, 90W-10Cu to 10W-90Cu. Powder technologies were used to make samples to evaluate density, TC, and CTE. Measured TC lies among theoretical values predicted by several existing models.
        4.
        2003.12 서비스 종료(열람 제한)
        This study was carried out to obtain informations on the variations of oil content and fatty acid composition among 90 Korean perilla collections. Average oil content of 90 perilla collections was 44.2% with a range from 29.7% to 61.9%. Perilla collections with late-maturing, super-large seed and gray seed coat showed higher oil content than other types in general. Average saturated fatty acid content in perilla oil was 9.0% with a range from 8.2% to 10.7%, while average unsaturated fatty acid content varied from 89.3% to 91.8% with a mean of 91.0%. Contents of saturated and unsaturated fatty acids were not related to maturity. There were no differences in the contents of saturated and unsaturated fatty acids according to maturity. Linoleic acid and linolenic acid contents were the highest in the super large-sized group(15.5%) and in the large-sized seed group(61.4%), respectively, while contents of fatty acids among the perilla collections were variable with different seed coat colors. Most of the traits studied were not significantly correlated with oil content, but linoleic acid(Ω-6) content was negatively correlated (r=-0.217*) with linolenic acid(Ω-3) content.