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        검색결과 101

        1.
        2023.05 구독 인증기관·개인회원 무료
        There have been a variety of issues related to spent nuclear fuel in Korea recently. Most of the issues are related to intermediate storage and disposal of spent nuclear fuel. However, recently, various studies have been started in advanced nuclear countries such as the United States to reduce spent nuclear fuel, focusing on measures to reduce spent nuclear fuel. In this study, a simple preliminary assessment of the thermal part was performed for the consolidation storage method which separates fuel rods from spent nuclear fuel and stores them. The preliminary thermal evaluation was analyzed separately for storing the spent fuel in fuel assembly state and separating the fuel rods and storing them. The consolidation storage method in separating the fuel rods was advantageous in terms of thermal conductivity. However, detailed evaluation should be performed considering heat transfer by convection and vessel shape when storing multiple fuel bundles simultaneously.
        4.
        2021.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the layered structures of immiscible Fe and Cu metals were employed to investigate the interface evolution through solid-state mixing. The pure Fe and Cu powders were cold-consolidated by high-pressure torsion (HPT) to fabricate a layered Cu-Fe-Cu structure. The microstructural evolutions and flow of immiscible Fe and Cu metals were investigated following different iterations of HPT processing. The results indicate that the HPTprocessed sample following four iterations showed a sharp chemical boundary between the Fe and Cu layers. In addition, the Cu powders exhibited perfect consolidation through HPT processing. However, the Fe layer contained many microcracks. After 20 iterations of HPT, the shear strain generated by HPT produced interface instability, which caused the initial layered structure to disappear.
        4,000원
        5.
        2021.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목조건축물에 주로 적용되고 있는 철물 접합 시스템은 모재인 나무와 접합부재인 철재 간의 강도 차이 및 재질의 이질성으로 인한 외관상의 위화감 등이 문제점으로 대두되고 있다. 재료 가공의 편의성으로 프리컷 시스템이 도입되었고, 시공성 을 해결하기 위한 새로운 재료 및 시스템의 개발이 요구된다. 본 연구에서는 자연재료를 그 원료로 하여 미관상 목조건축물에 위화감이 없는 황토 압밀 플레이트를 개발하였다. 황토 및 소석회를 원료로 하여 제작한 시험체의 양생방법(기건 양생, CO2 양 생)에 따른 성능을 평가하기 위해 질량 변화, 지압 강도, 흡수율, 표면상태, 열중량변화 측정 및 SEM을 통한 생성광물의 미시적인 부분을 관찰하였다. 또한 제조과정에서의 온실가스 배출 및 흡수에 따른 환경성능평가를 수행하였다. 기건 양생한 시험체에 비해 CO2 챔버에 양생한 시험체는 원료인 소석회의 탄산화 반응으로 인한 탄산칼슘의 생성으로 역학적 성능이 향상되었다는 것을 알 수 있었으며, 원료인 소석회의 탄산화반응으로 인해 생석회 제조시 발생하는 CO2량의 70% 이상을 재흡수 한다는 것을 알 수 있었다.
        4,000원
        6.
        2020.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this research, a new medium-entropy alloy with an equiatomic composition of FeCuNi was designed using a phase diagram (CALPHAD) technique. The FeCuNi MEA was produced from pure iron, copper, and nickel powders through mechanical alloying. The alloy powders were consolidated via a high-pressure torsion process to obtain a rigid bulk specimen. Subsequently, annealing treatment at different conditions was conducted on the four turn HPT-processed specimen. The microstructural analysis indicates that an ultrafine-grained microstructure is achieved after post-HPT annealing, and microstructural evolutions at various stages of processing were consistent with the thermodynamic calculations. The results indicate that the post-HPT-annealed microstructure consists of a dual-phase structure with two FCC phases: one rich in Cu and the other rich in Fe and Ni. The kernel average misorientation value decreases with the increase in the annealing time and temperature, indicating the recovery of HPT-induced dislocations.
        4,000원
        8.
        2018.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        ZrO2 is a candidate material for hip and knee joint replacements because of its excellent combination of biocompatibility, corrosion resistance and low density. However, the drawback of pure ZrO2 is a low fracture toughness at room temperature. One of the most obvious tactics to cope with this problem is to fabricate a nanostructured composite material. Nanomaterials can be produced with improved mechanical properties(hardness and fracture toughness). The high-frequency induction heated sintering method takes advantage of simultaneously applying induced current and mechanical pressure during sintering. As a result, nanostructured materials can be achieved within very short time. In this study, W and ZrO2 nanopowders are mechanochemically synthesized from WO3 and Zr powders according to the reaction(WO3 + 3/2 Zr→W+ 3/2 ZrO2). The milled powders are then sintered using high-frequency induction heating within two minutes under the uniaxial pressure of 80MPa. The average fracture toughness and hardness of the nanostructured W-3/2 ZrO2 composite sintered at 1300oC are 540 kg/mm2 and 5 MPa·m1/2, respectively. The fracture toughness of the composite is higher than that of monolithic ZrO2. The phase and microstructure of the composite is also investigated by XRD and FE-SEM.
        4,000원
        9.
        2018.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Recently, the properties of nanostructured materials as advanced engineering materials have received great attention. These properties include fracture toughness and a high degree of hardness. To hinder grain growth during sintering, it is necessary to fabricate nanostructured materials. In this respect, a high-frequency induction-heated sintering method has been presented as an effective technique for making nanostructured materials at a lower temperature in a very short heating period. Nanopowders of W and Al2O3 are synthesized from WO3 and Al powders during high-energy ball milling. Highly dense nanostructured W-Al2O3 composites are made within three minutes by high-frequency induction-heated sintering method and materials are evaluated in terms of hardness, fracture toughness, and microstructure. The hardness and fracture toughness of the composite are 1364 kg/mm2 and 7.1 MPa·m1/2, respectively. Fracture toughness of nanostructured W-Al2O3 is higher than that of monolithic Al2O3. The hardness of this composite is higher than that of monolithic W.
        4,000원
        10.
        2017.04 구독 인증기관 무료, 개인회원 유료
        Geotextile tubes are excellent design strategies for both shoreline protection and dewatering of fine materials. A difficulty with regard to designing geotextile tubes is the matching of the appropriate fabric with the site-specific infilled material and the unavailability of a test to determine the soil-geotextile consolidation properties. Existing methods simulate and predict the final tube shape based on the initial and final unit weights of the infill but the time required to reach the final shape or the compatibility of the infill are not being considered. This study proposes an improved hanging bag test to evaluate the compatibility of an infill with the geotextile fabric, and at the same time, to obtain the soil-geotextile consolidation properties. With the obtained consolidation properties, a big prototype simulation was possible, explaining the deformation behavior of the tube in the field. An analytical procedure used in modeling the tube was coupled with the large strain consolidation theory to simulate the filling and dewatering process.
        3,000원
        11.
        2016.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Waste oyster shells create several serious problems; however, only some parts of them are being utilized currently. The ideal solution would be to convert the waste shells into a product that is both environmentally beneficial and economically viable. An experimental study is carried out to investigate the recycling possibilities for oyster shell waste. Bulk ceramic bodies are produced from the oyster shell powder in three sequential processes. First, the shell powder is calcined to form calcium oxide CaO, which is then slaked by a slaking reaction with water to produce calcium hydroxide Ca(OH)2. Then, calcium hydroxide powder is formed by uniaxial pressing. Finally, the calcium hydroxide compact is reconverted to calcium carbonate via a carbonation reaction with carbon dioxide released from the shell powder bed during firing at 550oC. The bulk body obtained from waste oyster shells could be utilized as a marine structural porous material.
        4,000원
        12.
        2015.11 구독 인증기관 무료, 개인회원 유료
        특허소송의 항소심 관할 집중을 주요 골자로 한 민사소송법 및 법원조직법 개정안이 2016 년부터 시행된다. 이번 개정안은 지식재산권(특 허권, 실용신안권, 디자인권, 상표권, 품종보호권) 침해소송의 관할에 대하여 1심은 고등법원 소재지 지방법원(서울⋅광주⋅대전⋅대구⋅부산), 2심은 특허법원으로 집중하는 내용을 담고 있다. 그런데 특허침해소송에 대한 관할 집중을 1982 년부터 이미 이룬 바 있는 미국의 경우 CAFC의 운용에 대한 장⋅단점에 대한 논의 및 그 혁신안에 대한 연구가 상당히 축적되어 있고, 최근에는 CAFC의 권한을 축소하려는 대법원의 견제가 감지되는 상황이다. 유럽통합특허법원에 이어 아시아권의 통합특허법원의 설립가능성이 논의되는 현시점에서 우리나라 특허법원이 전문성과 국제적 위상을 강화하여 IP 허브코트로 도약하기 위해서는 전 자소송의 국제적 활용, 국제재판부 신설, 증거 조사의 실효성 강화, 진보성 심리 강화, 손해배 상의 적정화 등 제도적인 혁신이 선행되어야 할 것이다.
        4,000원
        13.
        2015.05 구독 인증기관 무료, 개인회원 유료
        2015년 제334회 국회 법제사법위원회에서 특허권 등의 사건의 사법 관할집중에 관한 민사소송 법 일부개정법률안 2건 및 법원조직법 일부개정 법률안 1건이 심의되었다. 민사소송법 일부개정 법률안은 지식재산권을 ‘특허권, 실용신안권, 디자인권, 상표권, 품종보호권(이하 ‘특허권 등’이라 한다)’ 그 외 지식재산권으로 구분하여 특허권 등에 관한 제1심 사건의 관할을 5개의 고등법원 소재지 지방법원으로 집중하는 것을 내용으로 하고 있으며, 법원조직법 일부개정법률안은 특허권 등 에 관한 사건의 항소심을 특허법원으로 관할 집중 하는 것을 골자로 하고 있다. 이외 2015년 입법 예고된 정부발의 특허법 일부개정법률안은 법원직권 뿐 아니라 당사자의 신청에 의해서도 특허에 관한 심결이 확정될 때까지 소송절차를 중지할 수 있도록 하고 있다. 국회에서 심의되었던 개정안들 에 따른 특허권 등에 대한 관할 집중은 지금까지 제기되었던 소송지연, 판결의 신뢰성 저하, 2중의 비용과 노력 문제, 전문성의 문제 등을 해소하는 데 도움이 될 것으로 본다. 그러나 지식재산권을 설권적 권리와 비설권적 권리로 구분하여 관할집 중 대상 범위를 법률로 정하는 것은 자의적인 측 면이 있어서 좀 더 신중히 접근할 필요가 있다고 생각한다. 관할 집중의 필요성과 장점에 대해서는 오랜 논의 결과 어느 정도의 공감대는 형성된 것 으로 보인다. 그럼에도 불구하고 사법접근성 저하 와 실효성에 대한 의문 등의 우려가 여전히 제기 되고 있다. 한편, 관할집중으로 인한 병합심리에 서 발생할 수 있는 실무적 절차 및 소송대리권의 범위 등에 대한 검토가 충분히 되지 않았다는 점 이 지적될 수 있다. 지식재산권 사건의 관할집중 은 제기되고 있는 우려와 관련 이슈들에 대해서 신중히 검토하여 방안을 마련하여 시행한다면 보 다 성공적인 결과를 가져올 것이다.
        4,200원
        14.
        2015.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In industrial society, the core competency of company was depend on the productivity. However the knowledge information era of the 21st century, the market power moved to downstream, the core competency of company is moved from productivity to how to make the products meet the market. Inventory was the burden of the company management. Most of company trying to reduce the inventory. In this study, analyze the impact of inventory to company's operating profit and the impact of distribution center consolidation to total inventory of company.
        4,000원
        15.
        2015.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the behavior of densification of copper powders during high-pressure torsion (HPT) at room temperature is investigated using the finite element method. The simulation results show that the center of the workpiece is the first to reach the true density of copper during the compressive stage because the pressure is higher at the center than the periphery. Subsequently, whole workpiece reaches true density after compression due to the high pressure. In addition, the effective strain is increased along the radius during torsional stage. After one rotation, the periphery shows that the effective strain is increased up to 25, which is extensive deformation. These high pressure and severe strain do not only play a key role in consolidation of copper powders but also make the matrix harder by grain refinement.
        3,000원
        16.
        2015.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        TiH2 nanopowder was made by high energy ball milling. The milled TiH2 and CNT powders were then simultaneously synthesized and consolidated using pulsed current activated sintering (PCAS) within one minute under an applied pressure of 80 MPa. The milling did not induce any reaction between the constituent powders. Meanwhile, PCAS of the TiH2-CNT mixture produced a Ti-TiC composite according to the reaction (0.92TiH2 + 0.08CNT→0.84Ti + 0.08TiC + 0.92H2, 0.84TiH2 + 0.16CNT→0.68Ti + 0.16TiC + 0.84H2). Highly dense nanocrystalline Ti-TiC composites with a relative density of up to 99.7% were obtained. The hardness and fracture toughness of the dense Ti-8 mole% TiC and Ti-16 mole% TiC produced by PCAS were also investigated. The hardness of the Ti-8 mole% TiC and Ti-16 mole% TiC composites was higher than that of Ti. The hardness value of the Ti-16 mole% TiC composite was higher than that of the Ti-8 mole% TiC composite without a decrease in fracture toughness.
        4,000원
        17.
        2014.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        사용후핵연료 또는 고준위폐기물의 안전한 처분을 위하여 지난 수십 년 동안 많은 나라들이 다양한 처분대안을 연구하여 왔다. 본 논문에서는 심지층처분기술에 있어서 사용후핵연료를 직접 처분하는 방안으로서 처분효율 향상을 위한 다양한 방 안 중의 하나로 고려할 수 있는 PWR 사용후핵연료 집합체를 해체하여 연료봉을 밀집한 경우에 대한 처분 효율을 분석하였 다. 이를 위하여, 우선 사용후핵연료 연료봉 밀집개념과 관련 처분용기 및 심지층처분 개념을 설정하였다. 이 개념에 근거하 여 심지층 처분시스템의 공학적방벽 설계에 있어서 가장 중요한 요건인 완충재의 온도 제한요건을 만족시키는지 여부를 확 인하기 위하여 각 처분개념 별로 열해석을 수행하였다. 그리고, 처분공 간격, 처분터널 간격 및 처분용기 열발산 면적에 따 른 열해석 결과를 바탕으로, 단위처분면적 관점에서의 처분효율을 비교/분석하고 평가하였다. 또한, 사용후핵연료봉을 밀 집시킨 경우에 있어서 냉각기간에 따른 처분개념을 분석하였다. 분석결과에 따르면 사용후핵연료봉을 밀집하여 심지층처 분하는 경우 처분효율 측면에서 불리한 것으로 판단되었다. 다만, 사용후핵연료의 냉각기간을 70년 이상으로 장기화 할 경 우 처분효율은 향상될 것으로 예상되지만, 사용후핵연료의 내구성 및 장기저장에 따른 조건 등 추가적인 분석이 필요하다.
        4,200원
        18.
        2014.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The current concern about these materials (MoSi2 and NbSi2) focuses on their low fracture toughness below theductile-brittle transition temperature. To improve the mechanical properties of these materials, the fabrication of nanostructuredand composite materials has been found to be effective. Nanomaterials frequently possess high strength, high hardness, excellentductility and toughness, and more attention is being paid to their potential application. In this study, nanopowders of Mo, Nb,and Si were fabricated by high-energy ball milling. A dense nanostructured MoSi2-NbSi2 composite was simultaneouslysynthesized and sintered within two minutes by high-frequency induction heating method using mechanically activated powdersof Mo, Nb, and Si. The high-density MoSi2-NbSi2 composite was produced under simultaneous application of 80MPa pressureand an induced current. The sintering behavior, mechanical properties, and microstructure of the composite were investigated.The average hardness and fracture toughness values obtained were 1180kg/mm2 and 3MPa·m1/2, respectively. These fracturetoughness and hardness values of the nanostructured MoSi2-NbSi2 composite are higher than those of monolithic MoSi2 orNbSi2.
        4,000원
        19.
        2013.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Nanocrystalline materials have recently received significant attention in the area of advanced materials engineering due to their improved physical and mechanical properties. A solid-solution nanocrystalline powder, (Ti,Mo)C, was prepared via high-energy milling of Ti-Mo alloys with graphite. Using XRD data, the synthesis process was investigated in terms of the phase evolution. Rapid sintering of nanostuctured (Ti,Mo)C hard materials was performed using a pulsed current activated sintering process (PCAS). This process allows quick densification to near theoretical density and inhibits grain growth. A dense, nanostructured (Ti,Mo)C hard material with a relative density of up to 96 % was produced by simultaneous application of 80 MPa and a pulsed current for 2 min. The average grain size of the (Ti,Mo)C was lower than 150 nm. The hardness and fracture toughness of the dense (Ti,Mo)C produced by PCAS were also evaluated. The fracture toughness of the (Ti,Mo)C was higher than that of TiC.
        4,000원
        20.
        2013.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Spherical Ti-6Al-4V powders in the size range of 250 and 300 µm were uniformly doped with nano-sized hydroxyapatite (HAp) powders by Spex milling process. A single pulse of 0.75-2.0 kJ/0.7 g of the Ti-6Al-4V powders doped with HAp from 300 mF capacitor was applied to produce fully porous and porous-surfaced Ti-6Al-4V implant compact by electro-discharge-sintering (EDS). The solid core was automatically formed in the center of the compact after discharge and porous layer consisted of particles connected in three dimensions by necks. The solid core increased with an increase in input energy. The compressive yield strength was in a range of 41 to 215 MPa and significantly depended on input energy. X-ray photoelectron spectroscopy and energy dispersive x-ray spectrometer were used to investigate the surface characteristics of the Ti-6Al-4V compact. Ti and O were the main constituents, with smaller amount of Ca and P. It was thus concluded that the porous-surfaced Ti-6Al-4V implant compacts doped with HAp can be efficiently produced by manipulating the milling and electro-discharge-sintering processes.
        4,000원
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