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        검색결과 4

        1.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Thermal protection systems (TPS) are a group of materials that are indispensable for protecting spacecraft from the aerodynamic heating occurring during entry into an atmosphere. Among candidate materials for TPS, ceramic insulation materials are usually considered for reusable TPS. In this study, ceramic insulation materials, such as alumina enhanced thermal barrier (AETB), are fabricated via typical ceramic processing from ceramic fiber and additives. Mixtures of silica and alumina fibers are used as raw materials, with the addition of B4C to bind fibers together. Reaction-cured glass is also added on top of AETB to induce water-proof functionality or high emissivity. Some issues, such as the elimination of clumps in the AETB, and processing difficulties in the production of reusable surface insulation are reported as well.
        4,000원
        2.
        2019.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This is an experimental study where the coefficient of friction between engine pulley and V-Belt is obtained. The experimental method is applied pulleys made of existing steel and aluminium materials. The relative friction workpiece is a v-belt incorporating rubber with cloth. The friction test uses a pin-on-disk friction modulator and measures the coefficient of friction depending on the number of revolutions in the disc. As a result, in the case of aluminum material, there was a sliding phenomenon because the coefficient of friction was small when accelerating and decelerating. Also, the variation of the friction coefficient was severe when the rotation speed was increased or decreased. Therefore, it is considered that the aluminum pulley is slippery even if it is fit to the structural rigidity. Therefore, in order to secure a stable friction coefficient, the pulley groove surface will be surface-treated, a special alloy is added, or a heat treatment is required.
        4,000원
        3.
        2007.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
          A space launch vehicle system represents a typical example of large-scale multi-disciplinary systems, consisting of subsystems such as mechanical structure, electronics, control, telecommunication, propulsion, material engineering etc. A lot of cost is
        4,000원
        4.
        2004.10 구독 인증기관 무료, 개인회원 유료
        Risk Management is an organized method for identifying and measuring risk and for selecting, developing, and implementing options for the handling of risk. The Risk management covers all programatic and technical factors which affect the system development performance, cost, and schedule. While technical issues are primary concern for systems engineering during a program, the three elements(performance, cost, and schedule) must be balanced for a successful risk management process and program. This paper describes the risk management process and intial results for the KSLV-I(Korea Space Launch Vehicle-I) program using computer-aided systems engineering tool, Cradle. The risk management process of KSLV-I program is similar to the general risk management process, but it has its own specific features to manage large-scale complex characteristics of KSLV-I program.
        3,000원