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        검색결과 113

        41.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the present study, Zr-base metallic glass(MG)/diamond composites are fabricated using a combination of gas-atomization and spark plasma sintering (SPS). The densification behaviors of mixtures of soft MG and hard diamond powders during consolidation process are investigated. The influence of mixture characteristics on the densification is discussed and several mechanism explaining the influence of diamond particles on consolidation behaviour are proposed. The experimental results show that consolidation is enhanced with increasing diamond/Metallic Glass(MG) size ratio, while the diamond fraction is fixed.
        4,000원
        42.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        High-pressure abrasive entrained jet have rapidly become important machining technology over the last two decades. However, suspension jet by high-pressure has been recently developed for packaging sawing. Ideally, diamond materials should be used for components in abrasive water-jet systems that are subject to high erosive conditions. Using the diamond orifices improve maintenance and extend wear part life. This paper gives insights to using an abrasive suspension jet with diamond orifice. The influences of orifice material and orifice design are evaluated.
        4,000원
        43.
        2008.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This article presents the successful consolidation of the mixed Co and Diamond powders for a drilling segment by the combined application of magnetic pulsed compaction (MPC) and subsequent sintering, and their properties were analyzed. Homogeneous hardness (Hv 220) and density (97%) of sintered bulks fabricated by MPC were obtained by the new technique, where higher pressure has been employed for short period of time than that of general process. A fine microstructure and homogeneous hardness in the consolidated bulk were observed without cracks. Relatively higher drilling speed of 9.61 cm/min and life time of 6.55 m were found to the MPCed specimens, whereas the value of the specimens fabricated by general process was 11.71 cm/min and 7.96 m, respectively. A substantial improvement of mechanical properties of segment was achieved through this study.
        4,000원
        44.
        2007.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본고에서 두 번역자의 번역에 대한 고찰을 통해 다음과 같은 점을 확인할 수 있었다. 우선 두 사람은 불교의 종교적 권위을 세우는 문제에 대해 고심하였던 것으로 보인다. 그래서 붓다의 완성된 모습, 위대성, 성스러움 등을 부각시키기 위하여 번역과정에 미묘한 가필이나 왜곡을 감행한다. 이 점은 두 사람 모두에게 적용되지만 특히 구마라집의 경우 특징적으로 나타나고 있다. 그러나 수부티(Subhūti)를 구마라집은 須菩提로, 玄獎은 善現으로 옮긴 것을 보면 직역, 의역의 원칙이 역전되어 나타나는 경우도 있다. 구마라집은 중국인들의 쉬운 이해를 통해 중국의 사유방식 속에서 인도의 것과 유사한 것을 찾기 위해 노력하였고, 현장은 인도 불교의 사유방식을 중국인들에게 분명하게 보여주고자 하였던 것으로 이해하는 것이 적절할 것으로 보인다. 보살승(현장)과 아뇩다라삼먁삼보리(구마라집)의 번역차이는 이러한 번역원칙의 역전이 나타나는 대목인 동시에 또 다른 설명을 필요로 한다. 구마라집은 인도에서 이미 극복된 소승의 수행법을 중국에서 답습할 필요가 없다고 생각하여 보살이 추구하는 무상정등각, 즉 아뇩다라삼먁삼보리를 바로 수행의 목적으로 제시하였던 것으로 살펴볼 수 있다. 한편 어떻게 마음을 유지하고(住), 닦아가며(修), 번뇌를 항복시킬 것인가(降) 하는 수행방법의 질문과 답변을 옮기면서 구마라집과 현장의 번역에 차이가 나타남을 살펴보았다. 이와 관련하여 필자는 구마라집이 소승의 계율주의와 수행주의에 반기를 들었던 대승불교의 출발을 교리와 수행에도 일관되게 적용하고자 하는 생각으로 修를 번역하지 않았다고 보았다.
        6,100원
        45.
        2006.09 구독 인증기관·개인회원 무료
        For improvement of wear resistance property of atmospheric thermal plasma sprayed molybdenum (Mo) coating, diamond deposition on the atmospheric plasma sprayed molybdenum coating by the combustion flame chemical vapor deposition (CFCVD) has been operated. In this study, to diminish the thermal damage of the substrate during operation, a thermal insulator was equipped between substrate and water-cooled substrate holder. Consequently, diamond particles could be created on the Mo coating without fracture and peeling off. From these results, it was found that this process had a high potential in order to improve wear resistance of thermal sprayed coating.
        46.
        2006.09 구독 인증기관·개인회원 무료
        Diamond tools were fabricated by cold pressing and sintering under pressure at the temperature up to . Investigation of the microhardness behaviour of the segments was showed that increasing the cobalt ratio causes the increase of the hardness of the matrix material. This caused to decrease of the wear rate of the matrix. Because the matrix wears more slowly than the diamonds, the space between the cutting edges and the matrix is constantly reduced. The swarf cannot be carried away properly, and the segment will continuously lose its ability to cut with higher cobalt contents.
        47.
        2006.09 구독 인증기관·개인회원 무료
        High-purity and super-hard nano-polycrystalline diamond has been successfully synthesized by direct conversion from high-purity graphite under static pressures above 15 GPa and temperatures above . This paper describes research findings on the formation mechanism of nano-structure and on the contributing factor leading to high hardness.
        48.
        2006.09 구독 인증기관·개인회원 무료
        The purpose of this study was to examine the interfacial reaction between diamond grits and Ni-based, Ag-based, brazing filler metal, respectively. The morphology of the interface between diamond grits and Ni-based, filler metal exhibited a very good condition after this heat treatment. Cr-carbide and Ni-rich compounds were detected by XRD analysis in the vicinity of the interface between diamond grits and Ni-based, filler metal after vacuum induction brazing. Chromium carbide is considered to play an important role in the high bonding strength achieved between diamonds grits and the brazing alloy.
        50.
        2006.09 구독 인증기관·개인회원 무료
        Diamond segments were fabricated by cold pressing and sintering under pressure at the temperature up to . Based on the results of this investigation, it can be concluded that the segments containing 39wt.% cobalt in the matrix material have the highest bending strength at a fracture probability of 50 % due to the weibull distribution method. According to the weibull statistics, it was also determined that the transverse rupture strength was the best for 39 wt.% cobalt ratio in the matrix material for the fracture probability when the other variables are the same.
        51.
        2006.09 구독 인증기관·개인회원 무료
        In this paper, the fundamental attributes, phase composition of three pre-alloyed powders for diamond tools by water atomization were investigated. The density, hardness, bend strength and bending modulus of their hot pressing samples were examined. The results showed that the three pre-alloyed powders have excellent low temperature sintering characteristics. The physical and mechanical properties of the samples were found to be nearly the same as those of fine cobalt powders.
        52.
        2006.09 구독 인증기관·개인회원 무료
        The present study has shown that the effect of boron and phosphorus in Ni-Cr-Si-X alloy to interfacial reactions and bonding strength of diamond-steel substrate, and the influence of various construction parameters on the formation of the topography of the tool. And these factors are required to making a good brazed tool. The microstructures and phase change of the brazed region were analyzed into SEM, EDS. According to the electron probe microanalysis, while brazing, the chromium present in the brazing alloy segregated preferentially to the surface of the diamond to form a chromium rich reaction product, which was readily wetted by the alloy.
        53.
        2006.09 구독 인증기관·개인회원 무료
        The ultrahigh pressure process for synthesizing diamond grits is due to make a quantum leap: the raw materials will incorporate diamond seeds with a predetermined pattern. The result is doubling the diamond yield with a narrower size distribution. Moreover, the shape of diamond crystals can be precisely tuned. For example, diamond octahedra or diamond cubes, that are not available today, can be mass-produced. The new technology is now being implemented worldwide so the future diamond grits will have improved quality at reduced prices.
        54.
        2006.09 구독 인증기관·개인회원 무료
        A revolutionary "Active Braze Coated Diamond" (ABCD) has been developed for bonding diamond grits firmly in the metal matrix. The molten braze is wetted and reacted with diamond to form strong chemical bond at the interface so that the diamond does not become knocked out of tools. The ABC is a nickel alloy that can form metallurgical diffusion bondswith the metal matrix. In essence, ABCD turns diamond into a metal grain so that the diamond tools can be made by conventional powder metallurgical process without being concerned about the poor bonding between matrix metal powder and the diamond as before.
        55.
        2006.09 구독 인증기관·개인회원 무료
        Metal-bonded diamond impregnated tools are being increasingly used in the processing of stone and ceramics, road repair, petroleum exploration, etc. Although the main tool wear mechanisms have been identified, the scientific background is inadequate and fundamental research has to be carried out to better understand the tool field behaviour. This work addresses the complex issues of modelling abrasive wear of the metallic matrix under laboratory conditions. The generated data indicates that the matrix wear resistance can be assessed in a simple manner; whereas tests carried out on diamond impregnated specimens may aid prediction of the tool life in abrasive applications.
        56.
        2006.09 구독 인증기관·개인회원 무료
        We found that the """interface reaction between Ni-based alloy bond, diamond, and steel core is very critical in bond strength of diamond tool. None element from metal bond diffuses into the steel core but the Fe element of steel core was easily diffused into the bond. This diffusion depth of Fe has a great effect on the bonding strength. The Cr in steel core accelerated the Fe diffusion and improved the bond strength, on the other hand, carbon decreased the strength. Ni-based alloy bond including Cr was chemically bonded with diamond by forming Cr carbide. However, the Cr and Fe in STS304 were largely interdiffused, the strength was very low. The Cr passivity layer formed at surface of STS304 made worse strength at commissure in brazing process.
        57.
        2006.09 구독 인증기관·개인회원 무료
        Currently Chemical Mechanical Planarization (CMP) has become an essential step in the overall semiconductor wafer fabrication technology. Especially the CMP pad conditioner, one of the diamond tools, is required to have strong diamond cohesion. Strong cohesion between diamond and metal matrix prevents macro scratch on the wafer during CMP Process. Typically the diamond tool has been manufactured by sintered, brazed and electro-plated methods. In this paper, some results will be reported of cohesion between diamond and metal matrix of the diamond tools prepared by three different manufacturing methods. The cohesion force of brazed diamond tool is found stronger than the others. This cohesion force is increased in reverse proportion to the contact area of diamond and metal matrix. The brazed diamond tool has a strong chemical combination of the interlayer composed of Cr in metal matrix and C in diamond, which enhance the interfacial cohesion strength between diamonds and metal matrix.
        58.
        2006.09 구독 인증기관·개인회원 무료
        Thermal management is one of the critical aspects in the design of highly integrated microelectronic devices. The reliability of electronic components is limited not only to operating temperature but also by the thermal stresses caused during the operation. The need for higher power densities calls for use of advanced heat spreader materials. A copper diamond composite has been developed with high thermal conductivity (λ) and tailorable coefficient of thermal expansion (CTE). Copper diamond composites are processed via gas pressure assisted infiltration with different copper alloys. Emphasis has been placed on the addition of trace elements in deisgning the copper alloys to facilitate a compromise between thermal conductivity and mechanical adhesion. The interfaces between the alloy and the diamond are related to the thermal properties of these copper composites.
        59.
        2006.09 구독 인증기관·개인회원 무료
        Amorphous diamond has a very low work function (1 eV) at modest temperature (150℃). It has been coat coated on electron emitting electrodes. Such electrodes are used for cold cathode fluorescence lamps (CCFL) that illuminate liquid crystal displays (LCD) for rnote books and television sets. Amorphous diamond can dramatically reduce the turn-on voltage to lit CCFL so the lamp life can be greatly extended. Moreover, the electrical current can be increased to enhance the brightness of the light.
        60.
        2006.09 구독 인증기관·개인회원 무료
        A new extra-fine grade Ni powder (XF Ni) has demonstrated increased sintering activity in Co-Fe-Ni binders for diamond tool applications. XF Ni has the advantage of significantly lower cost than XF Co. Up to 30% of XF Co was substituted with XF Ni while maintaining comparable apparent hardness and transverse rupture strength to pure Co binders. Ni substantially increased the diffusion of Fe. Diamond tool producers can take advantage of the improved sintering properties of XF Ni powder to substantially lower material costs.
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