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        검색결과 5

        1.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Since the launch of the Herschel Space Observatory, our understanding about the photo-dissociation regions (PDR) has taken a step forward. In the bandwidth of the Fourier Transform Spectrometer (FTS) of the Spectral and Photometric Imaging REceiver (SPIRE) on board Herschel, ten CO rotational transitions, including J = 4-3 to J = 13-12, and three fine structure lines, including [Ci] 609, [Ci] 370, and [Nii] 205 μm, are covered. I present our findings from the FTS observations at the nuclear region of M83, based on the spatially resolved physical parameters derived from the CO spectral line energy distribution (SLED) map and the comparisons with the dust properties and star-formation tracers. This article discusses (1) the potential of using [Nii] 205 and [Ci] 370 μm as star-formation tracers; (2) the excitation mechanisms of warm CO in the nuclear region of M83.
        3,000원
        2.
        2006.09 구독 인증기관·개인회원 무료
        The new alloy1) is made from rapidly solidified Al-Ni-Zr-Ce aluminum alloy powder, and has the following unique mechanical characteristics:(1) The stress-strain curve shows a yield point; (2) The alloy shows high heat resistance; (3) Although the alloy is submicron particle diameter, it shows excellent creep resistance. We observed the micro structures of this new alloy, and it is thought that is based on the following reasons:(1) The dislocation strongly adheres to the alloy’s many crystal boundaries;(2) The added alloying elements have a small diffusion coefficient in aluminum;(3) The tiny intermetallic compound particles crystallizing at the grain boundary.
        3.
        2006.09 구독 인증기관·개인회원 무료
        We successfully developed Al-Si-Transition Metal (TM) -Rare Earth (RE) Powder Metallurgy (P/M) alloy with fine microstructure, which has high strength at high temperature. This material was compacted rapidly solidified powder and directly consolidated by hot extruding or forging. Before consolidating, rapid heating was performed on powder compaction in order to keep the fine microstructure in powder state. We have also investigated the processing conditions of this new alloy by computing simulations and experiments.
        4.
        2006.04 구독 인증기관·개인회원 무료
        TiC-and Ti(C,N)-based cermets are excellent in semi-and final finishing of work piece during cutting operations. Typical microstructure of the cermets is a core/rim structure. The undissolved Ti(C,N) cores contribute to their high hardness while the rim phases, (Ti,M1,M2)(C,N)-type solid solutions, play great roles in enhancing the toughness. In this paper, various ultrafine pre-mixed MeC-Ni powders were synthesized and the powders were sintered or hot pressed after mixing in order to control the size and volume fractions of core and rim phases in the system. This paper will present the factors determining the microstructure along with mechanical properties.
        5.
        2000.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 Electron Cyclotron Resonance plasma etching system 을 이용한 Ta 박막의 미세 식각 특성을 연구하였다. 염소 plasma를 사용하여 microwave power, RF Power, working pressure, gas chemistry 등의 변화에 따른 식각 profile의 영향을 조사하였고, pattern density가 증가함에 따라 발생하는 microloading 현상을 0.2μm 이하의 패턴에서 확인 하였다. 이를 개선하기 위하여 식각 과정을 두 단계로 분리하는 2단계 식각 공정을 수행하였으며 이를 통해 우수한 식각 profile을 얻을 수 있었다.
        4,000원