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        검색결과 344

        161.
        2011.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Effect of Cu content on microstructural and magnetic properties of a (wt.%), (x = 0.2, 0.3, 0.4, 0.5) strip-cast was studied. The average inter-lamellar spacing in the free surface and wheel side of the strip cast increased as the Cu content increases. The grain uniformity, the grain alignment, and (00L) texture of the strip cast increased with Cu contents up to 0.4 wt.%. These microstructural changes were attributed to the decrease of the effective cooling rate of the melted alloy caused by the decrease of the melting temperature of resulting from Cu addition. Coercivity and remanence were increased because of the grain alignment and (00L) texture improvement with Cu contents up to 0.4 wt.%.
        4,000원
        162.
        2011.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Energy resistance welding (ERW) is a pipe-producing process that has high productivity and low manufacturing cost. However, the high heat input of ERW degrades the mechanical property of the pipe. This study investigates the effect of heat input and alloying elements on microstructure and mechanical properties of ERW pipes. As the heat input increased, the ferrite amount increased. The ferrite amount in the weld centerline was larger than t at in the weld boundary. Medium carbon steels (S45C and K55) having 0.3~0.4wt.% carbon yielded a significant difference of ferrite amount in the weld centerline and weld boundary. High alloyed steels (DP780 and K55) having 1.5~1.6wt.% Mn showed a ferrite rich zone in the weld centerline. These phenomena are probably due to decarburization and demanganisation in the weld centerline. As the ferrite fraction increased, the hardness decreased a little for the S45C steels. In addition, DP780 steels and K55 steels showed that the hardness drops when those steels have a ferrite rich zone. But we demonstrated the good tensile property of the DP780 steels and K55 steels in which Mn is included.
        4,000원
        163.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, as high temperature performance capable thermoelectric materials was manufactured by powder metallurgy.The as-casted Fe-Si alloy was annealed for homogenization below for 3 h. Due to its high brittleness, the cast alloy transformed to fine powders by ball-milling, followed by subsequent compaction (hydraulic pressure; 2 GPa) and sintering (, 12 h). In order to precipitate , heat treatment was performed at with varying dwell time (7, 15 and 55 h). As a result of this experiment thermoelectric phase was quickly transformed by powder metallurgical process. There was not much change in powder factor between 7h and 55h specimens.
        4,000원
        164.
        2010.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        High strength sheet steels for automobile are seriously compromised by hydrogen embrittlement. This issue has been continuously studied, but the field of interest, which lies between microstructural characteristics and hydrogen behavior with hydrogen charging, has not yet been thoroughly investigated. This study was done to investigate the behavior of hydrogen according to the hydrogen volume fraction on 590MPa grade DP steels, which are developed under hydrogen charging conditions as high strength sheet steels for automobiles. The penetration depths and the mechanical properties, according to charging conditions, were investigated through the distribution of micro-hardness and the microstructural observation of the subsurface zone. It was found that the amount of hydrogen trapping in 590MPa DP steels was related to the austenite volume fraction. It was confirmed that the distribution of micro-hardnesses according to the depth of the subsurface zone under the free surface showed the relationship of the depth of the hydrogen saturation between the charging conditions.
        4,000원
        165.
        2010.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Mo thin films were used for the back electrode because of the low resistivity in the Mo/CuInGaSe2 contact inchalcopyrite solar cells. 1µm thick Mo thin films were deposited on soda lime glass by varying the Ar pressure with the dc-magnetron sputtering process. The effects of the Ar pressure on the morphology of the Mo back electrode were studied andthe relationships between the morphology and electro-optical properties, namely, the resistivity as well as the reflectance of theMo thin films, were investigated. The resitivity increased from 24µΩ·cm to 11833µΩ·cm; this was caused by the increasedsurface defect and low crystallinity as the Ar pressure increased from 3×10−3 to 3×10−2Torr. The surface morphologies ofthe Mo thin films changed from somewhat coarse fibrous structures to irregular and fine celled strucutures with increased surfacecracks along the cell boundaries, as the Ar pressure increased from 3×10−3 to 3×10−2Torr. The changes of reflectances in thevisible light range with Ar pressures were mainly attributed to the surface morphological changes of the Mo thin films. Thereflectance in the visible light range showed the highest value of 45% at 3×10−3Torr and decreased to 18.5% at 3×10−2Torr.
        4,000원
        166.
        2010.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        High speed steels (HSS) were used as cutting tools and wear parts, because of high strength, wear resistance, and hardness together with an appreciable toughness and fatigue resistance. Conventional manufacturing process for production of components with HSS was used by casting. The powder metallurgy techniques were currently developed due to second phase segregation of conventional process. The powder injection molding method (PIM) was received attention owing to shape without additional processes. The experimental specimens were manufactured with T42 HSS powders (59 vol%) and polymer (41 vol%). The metal powders were prealloyed water-atomised T42 HSS. The green parts were solvent debinded in normal n-Hexane at for 24 hours and thermal debinded at mixed gas atmosphere for 14 hours. Specimens were sintered in , gas atmosphere and vacuum condition between 1200 and . In result, polymer degradation temperatures about optimum conditions were found at and . After sintering at gas atmosphere, maximum hardness of 310Hv was observed at . Fine and well dispersed carbide were observed at this condition. But relative density was under 90%. When sintering at gas atmosphere, relative density was observed to 94.5% at . However, the low hardness was obtained due to decarbonization by hydrogen. In case of sintering at the vacuum of torr at temperature of , full density and 550Hv hardness were obtained without precipitation of MC and in grain boundary.
        4,000원
        167.
        2010.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A new High Frequency Induction Heating (HFIH) process has been developed to fabricate dense reinforced with Fe-Ni magnetic metal dispersion particles. The process is based on the reduction of metal oxide particles immediately prior to sintering. The synthesized /Fe-Ni nanocomposite powders were formed directly from the selective reduction of metal oxide powders, such as NiO and . Dense /Fe-Ni nanocomposite was fabricated using the HFIH method with an extremely high heating rate of . Phase identification and microstructure of nanocomposite powders and sintered specimens were determined by X-ray diffraction and SEM and TEM, respectively. Vickers hardness experiment were performed to investigate the mechanical properties of the /Fe-Ni nanocomposite.
        4,000원
        168.
        2010.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Sm-16.7wt%Co alloy powders were prepared by high energy ball milling under the conditions of various milling time and the content of process control agent (PCA), and their microstructure and magnetic properties were investigated to establish optimum processing conditions. The initial powders employed showed irregular shape and had a size ranging from 5 to . After milling for 5 h, the shape of powders changed to round shape and their mean powder size was approximately , which consisted of the agglomerated nano-sized particles with 15 nm in diameter. The coercivity was reduced with increasing the milling time, whereas the saturation magnetization increased. As the content of PCA increased, the powder size minutely decreased to approximately at the PCA content of 10 wt%. The XRD patterns showed that the main diffraction peaks disappeared apparently after milling, indicating the formation of amorphous structure. The measured values of coercivity were almost unchanged with increasing the content of PCA.
        4,000원
        169.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        기업의 소유와 경영에 관한 논의는 기업의 사회적 역할과 윤리의식이 결부되면서, 기업과 사회 환경이 소유와 경영에 어떠한 영향을 미치는지에 대한 관계를 모색하고자 하는 논의가 활발하게 진행되고 있다. 이러한 논의가 진행되는 이유는 기업의 사회적 책임이 강조되면서 기업의 경영체제가 장기적으로는 기업의 경영성과를 결정하는 중요한 이슈 중의 하나로 인식되고 있기 때문이다. 기업경영에는 여러 가지의 유형이 있지만, 그 중 하나가 가족경영(family busine
        4,600원
        170.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 조직문화가 점진적혁신에 미치는 효과와 두 변수간의 관계에서 창의성과 A형성격의 조절효과를 검증하고자 하였다. 서비스업에 종사하는 접점종업원 306명으로부터 받은 설문을 바탕으로 실증분석하였다. 분석 결과 조직문화의 구성요소 중 친화적문화와 진취적문환는 프로세스혁신, 운영혁신, 서비스혁신 모두에 대하여 긍정적 영향을 미치는 것으로 나타났으며, 보존적문화와 합리적문화는 영향을 미치지 않거나 매우 미미한 영향을 미치는 것으로 나타났다. 조절효과에
        4,800원
        172.
        2009.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The pressureless sintering behavior of /Cu powder mixtures, prepared from /CuO and /Cu-nitrate, has been investigated. Microstructural observation revealed that powders with nano-sized Cu particles could be synthesized by hydrogen reduction method. The specimens, pressureless-sintered at for 4 min using infrared heating furnace with the heating rate of /min, showed the relative density of above 90%. Maximum hardness of 16.1 GPa was obtained in /MgO/Cu nanocomposites. The nanocomposites exhibited the enhanced fracture toughness of 4.3-5.7 , compared with monolithic . The mechanical properties were discussed in terms of microstructural characteristics
        4,000원
        173.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 2007년 만경강의 중∙상류의 3개 지점을 선정하여 어류의 길드특성 및 조직별 수은 함량을 분석하였다. 어류의 종조성 분석에 따르면 7과 26종이 채집되었으며, 주요 우점종은 갈겨니(47%)로 수질오염에 쉽게 사라지는 민감종(Senstive species)이 우점하였다. 상류의 S1지점은 균등도 및 종 다양도가 낮게 나타났으나 그 밖의 2개의 지점들에서는 종다양도 및 풍부도가 높은 것으로 나타났다. 내성도 길드 분석에 의하면 S1과 S2 지점에서는 민감종의 비율이 각각 70%, 42%을 보였으나 반면 공단이 나 도심지의 점오염원에 의해 영향을 받는 S3 지점은 민감종의 비율 감소(1%) 및 내성종의 비율(60%)이 증가하였다. 트로픽 길드 분석에서는 충식종의 비율이 S1에서 S3으로 갈수록 감소하였다. 이런 특성은 유기물질(BOD, COD), 영양염류(TN, TP), 전기전도도, 대장균수 및 부유물질에 근거한 이∙화학적 수질 평가 결과와 일치하였다. 물리적서식지평가(QHEI)는 3지점에서 모두 ‘양호’상태로 나타나 물리적 서식지가 양호한 상태일지라도 수질에 의해 어류의 종구성이 달라질 수 있음을 나타냈다. 어류의 조직(tissue) 내의 총 수은 함량 분석에 따르면, 평균 농도는 149.6 μg kg-1로서 식약청의 기준(500 μg kg-1) 에 따르면 어류 건강성에 영향을 줄만한 농도는 아닌 것으로 평가되었다. 각 조직별 수은 농축도는 근육에서 가 장 높았고, 신장, 척추, 간, 아가미의 순으로 나타났다.
        4,200원
        174.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 배추 재배시 기후변화에 대비하여 고온과 고농도의 이산화탄소 조건에서 생육반응과 세포조직의 변화를 알아보고자 수행하였다. 처리는 '대기중 온도+대기중 CO2 농도(Control)', '대기중 온도+대기보다 CO2 2배 상승(Elevated CO2)' '(대기온도보다 4℃ 상승+대기중 CO2 농도(Elevated temp.)', '대기온도보다 4℃ 상승+대기보다 CO2 2배 상승(Elevated temp.+CO2)'의 4가지 조건으로 처리하였다. 그 결과, 대기조건보다 온도만 높아지게 되면 배추의 생체중이 현저하게 저하되어 수량이 떨어지는 것으로 나타났고, 온도가 높아지고 CO2 농도가 동시에 올라가게 되면 생육이 어느정도 회복되는 것으로 나타났다. 또한 칼륨과 인산함량은 처리별로 차이가 없었지만 칼슘과 총질소함량은 온도만 높인 처리에서 높았고, 마그네슘 함량은 온도와 CO2 농도를 동시에 높인 처리에서 높게 나타났다. 배추잎의 세포 관찰결과 CO2 농도를 2배 정도 높인 처리에서 잎내의 전분함량이 증가하는 것으로 나타났고, 온도만 높인 처리에서 전분 함량이 가장 낮았다.
        4,000원
        175.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper is to test the modulating effect of organizational culture on the relationship between personality and incremental innovation, and study of the relationship between incremental innovation and service Quality in service industry. Based on 507 da
        4,200원
        176.
        2009.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The degree of WC decomposition and hardness of thermally sprayed WC-Co coatings are important factors determining the wear resistance of the coatings. In order to minimize the degree of decomposition and to increase hardness, the effects of processing parameters of high velocity oxyfuel(HVOF) spraying on various characteristics of nanostructured WC-12Co coating have been evaluated by an experimental design method. The HVOF sprayed WC-12Co coatings consisted of various carbide phases including WC, and , with a much reduced carbon content. The degree of WC decomposition and decarburization was affected by changing barrel length and spray distance. The hardness of WC-Co coatings was strongly related to droplet temperature at substrate, and increased with increasing fuel addition and/or decreasing spray distance. The effective control of processing parameters was discussed in detail for manufacturing a high performance WC-Co coating.
        4,000원
        177.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to research the characteristics of the pattern design and the weave construction of 67 fashion fabrics in women's Hanbok. All the fabrics were made by 100% silk. Arrangement, size, and the type of patterns were investigated for research of the pattern characteristics. Pattern weave and background weave were analyzed, then the weight and the thickness were measured for studying the fabric construction. The results were as follows. First, irregular arrangement was more commonly used than regular arrangement, and then the complex arrangement and the combination arrangement were appeared considerably because of the existence of the various patterns in a fabric. Third, the types of pattern weave construction were much more than those of background weave construction. This is caused by the expression of dimensional effect for patterns. This survey can be practically used for development of pattern design for Hanbok industry and furthermore it will contribute to revitalizing of Hanbok market to overcome design limit in the future.
        4,800원
        180.
        2008.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study addresses the development of a soy hamburger patty containing enzyme-treated textured soy protein (TSP) as a meat analogue. In order to reduce the beany flavor and enhance the texture, TSP was treated with 0.3% Flavourzyme for 5, 10, 20, or 30 min. The degree of hydrolysis and the water holding capacity of the TSP increased with increasing hydrolysis time. The oil binding capacity of the TSP also increased with increasing hydrolysis time, approaching the maximal value, 175.82%, at 30 min, whereas that of pork scored with the lowest value of 128.67%. The volume of pork was reduced to 81.5% as the result of heat treatment, whereas that of the TSP increased to 140.57%. The values of 'L', 'b', and 'δE' differed significantly (p〈0.001) with heat treatment, but the 'a' values did not differ significantly. With regard to texture, the hardness values were highest in the pork hamburger patty (PHP), and were lowest in the soy hamburger patty (SHP) containing untreated TSP. The hardness of the SHP containing TSP treated for 20 min did not differ significantly from that of the PHP. The cohesiveness and gumminess of the SHP treated for 20 min were highest, whereas those treated for 10 min were the lowest. The gumminess of the SHP treated for 20 min did not differ significantly from that of pork. The chewiness of the PHP was the highest, whereas that of the SHP treated for 5 min was the lowest. In our sensory evaluation, PHP evidenced the highest scores, followed by the SHP treated for 30 min, as color, texture, beany flavor, and overall quality all improved as the consequence of increasing enzyme treatment duration. In conclusion, it is believed that SHP has great potential as a substitute for meat, in that the flavor, texture, and beany flavor of SHP did not differ significantly from those of PHP.
        4,000원