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        검색결과 25

        1.
        2019.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        인공지능 시대의 도전에 종교학적으로 답하기 위해 폴 리쾨르(Paul Ricoeur)의 미메시스(mimèsis) 이론을 그의 종교적 해석학에 접붙였다. 이 접붙임을 통해 드러나는 종교적 텍스트의 본유적인 기능은 개인과 공동체가 종교적 텍스트를 읽고 해석하면서 개인과 공동체가 자신들이 가지고 있는 한정적인 시간성(Zeitlichkeit)을 넘어선 영원성(eternity)이나 공(空)과 같은 근원적인 시간성과 새로운 존재의 가능성을 보면서 일어나는 영혼의 변형과 서사적 정체성이다. 약한 인공지능(weak AI)의 경우, 인공지능이 지식적이고 교리적인 측면의 기능을 감당하게 되어 영혼의 변형이라는 종교적 텍스트의 본유적 기능이 강화될 것이다. 강한 인공지능(strong AI)의 경우, 인공지능이 앞으로 인간과 함께 살아가는 동반자가 될 수 있다는 점에서 강한 인공지능이 등장하기 전에 지금까지 종교적 텍스트가 형성해 온 다양한 종교적인 서사적 정체성을 인공지능 프로그램 안에 적극적으로 포함하는 컴퓨터 공학과의 협업이 강력하게 요청된다.
        5,500원
        2.
        2007.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbon contamination from the binder resin is an inherent problem with the metal powder injection molding process. Residual carbon in the W-Cu compacts has a strong impact on the thermal and electric properties. In this study, uncertainty was quantified to evaluate determination of carbon in a W-15%Cu MIM body by the combustition method. For a valid generalization about this evaluation, uncertainty scheme applied even to the repeatability as well as the uncertainty sources of each analyse step and quality appraisal sources. As a result, the concentration of carbon in the W-Cu part were measured as 0.062% with expanded uncertainty of 0.003% at 95% level. This evaluation example may be useful to uncertainty evaluation for other MIM products.
        4,000원
        4.
        2006.09 구독 인증기관·개인회원 무료
        Ti-6Al-4V has low specific gravity, high corrosion resistance and superior mechanical properties but it is very difficult to control oxygen content in MIM process. It is necessary to use powders with coarse particle size to decrease oxygen content of powders, so feedstocks with poor fluidity and sintered bodies with lower density are obtained in such cases. Fine titanium hydride-dehydride powders were blended with atomized powders to accomplish higher fluidity and sintered density. Sintered bodies had higher sintered density and mechanical properties equivalent to those of wrought materials by controlling oxygen content less than 0.35mass%.
        5.
        2006.09 구독 인증기관·개인회원 무료
        The metal injection molding process was applied to produce Ti-6Al-7Nb alloys using 3 types of mixed powders, first is a mixture of Ti and Al53.3Nb pre-alloyed powders, second is a mixture of Ti, TiAl and Nb powders, and third is a mixed elemental powders of Ti, Al and Nb. The effects of the 3 types of mixed powders and sintering conditions on the microstructure, relative density and mechanical properties of injection molded compacts were mainly investigated. The sintered compacts using first and second powders showed higher density and mechanical properties as compared to the compacts using the third powder which existed many and a little large pores in the microstructure because of the melting of Al during sintering steps. Also the oxygen content of the compacts using second powder was higher than that of the compacts using other powders. Eventually, the mechanical properties of the compacts using a mixture of Ti+Al53.3Nb or Ti+TiAl+Nb powders were above 800MPa in tensile strength and above 10% in elongation, which were similar to the properties of wrought materials.
        6.
        2006.09 구독 인증기관·개인회원 무료
        The MIM industry is currently focusing on parts that are used in automobiles and medical instruments. Many of the parts in these categories are very small and often not easy to machine because of its complex geometry. Therefore MIM is well suited for the production of these parts. We tested the sinterability of SUS316L ultra fine powders (3,4, 6, 8micron) produced by ATMIX high-pressure water-atomization, and it showed excellent results. A density of 97% theoretical was obtained by sintering at 1373K when using the ultra fine powder (3micron). Specifically, the finer the powder size, higher was the sintered density. The surface roughness and accuracy are also greatly improved with ATMIX ultra fine powder.
        7.
        2006.09 구독 인증기관·개인회원 무료
        Mo2FeB2 boride base cermets produced by a novel sintering technique, called reaction boronizing sintering through a liquid phase, have excellent mechanical properties and wear and corrosion-resistances. Hence, the cermets are applied to the injection molding die-casting machine parts and so on. We investigated that the effect of deoxidization and sintering temperature on mechanical properties and deformation of the MIM processed cermets. As a result, deoxidization temperature of 1323K and sintering temperature of 1518K were suitable. The MIM products of the cermets showed allowable dimensional accuracy and the same mechanical properties as the presssintered ones.
        9.
        2006.04 구독 인증기관·개인회원 무료
        The MIM technology is an alternative process for fabricating near net shape components that usually uses gas atomised powders with small size (< 20 μm) and spherical shape. In this work, the possibility of changing partially or totally spherical powder by an irregular and/or coarse one that is cheaper than the former was investigated. In this way, different bronze 90/10 components were fabricated by mixing three different types of powder, gas and water atomised with different particle sizes, in order to evaluate how the particle shape and size affect the MIM process.
        10.
        2006.04 구독 인증기관·개인회원 무료
        The kneading process and formulations of feedstock obviously affect the quality of MIM products. In the present work, the rheological behaviour of the composite MIM feedstock, metal matrix (Cu) with few additions of ceramic powders (Al2O3), was measured by a self-designed/manufactured simple capillary rheometer. Experimental results show that the distribution between powders and binder is more uniformly when blending time increased. Though high powder loading will increase the feedstock viscosity, the fluidity reveals relatively stable through the load curves of extrusion. Besides, the temperature-dependence of viscosity of the feedstock approximately follows an Arrehnius equation. Basing on Taguchi’s method, the kneading optimization conditions and the rheological model of the feedstock were established, respectively.
        11.
        2006.04 구독 인증기관·개인회원 무료
        In this paper, rheological characteristics of Metal Injection Moulding (MIM) feedstock using locally binder of palm stearin are presented. The feedstock consisted of 316L-grade stainless steel powder with three different particle sizes and the binders comprise palm stearin and polyethylene. The viscosity of MIM feedstock at different temperatures and shear rates was measured and evaluated. Results showed that, the feedstock containing palm stearin exhibited suitable rheological properties and suitable to produce a homogeneous feedstock that is favorable for injection molding process.
        12.
        2006.04 구독 인증기관·개인회원 무료
        More and more applications or demands for machine parts etc are expected for AISI 440C (hereinafter referred to as "440C") Stainless Steel because of its characteristic features, i.e. high-strength as well as high-corrosion resistance. This research has enabled us to obtain sintered products with good quality even under a wide range of temperature by utilizing the pinning effect of NbC, improving the relevant sintering feature of 440C Stainless Steel in the MIM method.
        13.
        2006.04 구독 인증기관·개인회원 무료
        To lower the cost of MIM products, the gate and runner materials and green parts with defects are usually recycled. It is necessary to understand what causes the recycled products to deteriorate. The results show that the viscosity of the 1R (recycled once) feedstock was slightly lower than that of the fresh material. However, as the number of recyclings increased, the viscosity increased, while the density decreased, and more defects were noticed duri ng solvent debinding. These deteriorations were mainly caused by the increase of the melting point of the backbone binder and the oxidation of the filler or paraffin wax.
        14.
        2006.04 구독 인증기관·개인회원 무료
        The results of investigations in screw design for metall injection molding (MIM) will be presented. The consistency of cavity pressure, metering time and MFQ (monitoring of feedstock quality; parameter measured during metering) was chosen to compare different screws. A simulation program was used to optimize the conveying and melting mechanisms in the plastification unit. The theoretical background of this simulation programm will be explained.
        15.
        2006.04 구독 인증기관·개인회원 무료
        The relationship between the powder particle size change and a mechanical property of the Metal Injection Molding (MIM) product was examined in detail. The XRD results indicate that the diffraction peaks of BCC appeared in compacts of powder particle size of 4 to as well as the bulk SUS630. However, the diffraction peaks from both BCC and FCC were observed in the compact with powder size less than . TEM observation revealed that the powder with those BCC/FCC two phase structure have a finely dispersed precipitates. Because the Si is ferrite stabilizing element, decrease of Si composition in the matrix phase by the precipitation resulted in formation of the retained austenite. Therefore, controlling the elements such as Si as well as oxygen decrease is very important to obtain a normal microstructure in ultra-fine powder (<3μm) injection molding.
        16.
        2006.04 구독 인증기관·개인회원 무료
        The development of Micro MIM as a new manufacturing process for metallic micro parts made of advanced functional materials has been the subject of considerable research over the last years. This paper addresses important quality aspects on processing of new materials by Micro-MIM. Three examples of new functional materials that can be processed are reviewed in this paper. The first example is two-component-Micro-MIM to obtain multi-functional devices. A micro positioning encoder consisting of a magnetic / non-magnetic material combination is presented. The second issue is series production of the replicate of the smallest human bone in the ear (stapes) from Titanium as an example of medical application. Quality assurance and reproducibility in terms of injection moulding parameters are addressed. In the third part, first results on the processing of the shape memory alloy NiTi by Micro-MIM are presented. Potential applications include biocompatible devices and transportation, for example automotive and aerospace. Processing routes and initial microstructures obtained are discussed.
        18.
        2002.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        For the austenitic stainless steel (304L) manufactured by metal injection molding(MIM), the effects of copper content and sintering temperature on the mechanical properties, antibacterial activities, corrosion resistance, and electric resistances were investigated. The specimens were prepared by injection molding of the premixed powders of water-atomized 304 L and Cu with poly-acetyl binders. The green compacts were prepared with various copper contents from 0 to 10 wt.% Cu, which were debound thermally at 873 K for 7.2 ks in gas atmosphere and subsequently sintered at various temperatures from 1323 K to 1623 K for 7.2 ks in Ar gas atmosphere. The relative density and tensile strength of the sintered compacts showed the minimum values at 5 and 8 wt.% Cu, respectively. Both the relative density and the tensile strength of the specimen with 10 wt.% Cu sintered at 1373 K showed the highest values, higher than those of copper-free specimen. Antibacterial activities investigated by the plastic film contact printing method for bacilli and the quantitative analysis of copper ion dissolved in water increased as the increase of the copper content to stainless steels. It was also verified by the measurement of pitting potential that the copper addition in 304 L could improve the corrosion resistance. Furthermore the electric conductivity increased with the increase of copper content.
        4,000원
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