• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1991년도 추계학술대회 논문집
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• pp.56-59
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• 1991

The polyervstalline $Cu_{0.28}Ag_{0.72}InSe_{4.4}S_{0.6}$ thin films are prepared by vacuum heat treatment of laver, which is deposited by direct resisting vacuum evaporation. From optical absorption spetra, the optical hand gap energy is determined to be 1.5[eV] at room temerature. From electrical method. hole concentration, resistivity and mobility are 9.3*$10^{18}$[$cm^{-3}$], 6*$10^{-2}$[$\Omega$$.$cm], 11.2[$\textrm{cm}^2$/V$.$sec] respectively at room temperature.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2004년도 춘계학술대회 논문집
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• pp.139-142
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• 2004

Nickel base superalloys are widely used for high temperature applications due to heat resisting capability and corrosion resistance at high temperatures. Superalloys with many strengthening alloying elements are frequently used in powder form to alleviate harmful effects of alloy segregation. HIP (hot isostatic pressing) and DB (diffusion bonding) as a form of solid-state bonding process is used to make turbine components, such as integrated turbine rotors. HIP/DB process requires many technical overcomes related to dimensional changes as well as microstructural control. In this research, HIP/DB process for nickel base superalloys, Udimet 720 and MM 247, were investigated with a view to control the dimensional change during the consolidation process. Simple disc-shaped cans were used to select the conceptual die design for the control of the dimensional change especially in radial direction. The change in the shape of consolidated shape was investigated using commercial FE code with constitutive equations fur low temperature plasticity deformation.

• 한국세라믹학회지
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• 제16권2호
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• pp.77-82
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• 1979

Diopside-Anorthite body was easily synthesized at relatively low temperature 1225℃, compared with the synthesizing temperature 1425℃ of Anorthite. Of Diopside-Anorthite body, the synthesizing temperature was considered to be higher than 1225℃ because Gehlenite, probably formed at 1220℃, was detected by X-ray diffraction. This body has excellent physical and electrical properties, i.e. electric resistivity (1.2×1014Ωcm), low dielectric constant (6.26) and low thermal expansion coeffcient (61.9×10-7/℃). It's hardness was good enough for electrical subsidiary. In addition, this body, Diopside-Anorthite, has exellent properties for heat resisting wares.

• 한국전산구조공학회논문집
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• 제14권1호
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• pp.11-19
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• 2001

기능경사재(FGM)는 구성 물질의 체적분율(volume fraction)이 복합재 전체에 걸쳐 연속적 그리고 기능적으로 분포되어 있어, 기존의 이종물질 접합식(bi-material-type) 복합재보다 현저히 우수한 열기계적 특성을 가진다. 하지만, 기능경사 내열복합재의 열-탄소성 거동은 체적분율의 분포형태와 경사층이 차지하는 상대두께비에 따라 절대적으로 좌우된다. 본 연구는 기능경사 내열복합재의 열-탄소성 특성의 이들 두 설계인자에 대한 파라메트릭 FEM해석을 다룬 것이다. 열-탄소성 이론과 유한요소 근사화에 따라 연구용 2차원 FEM 프로그램을 개발하고, 대표적인 3층 구조의 2차원 기능경사 내열복합재의 열-탄소성 특성을 설계변수의 다양한 조합에 따라 분석하였다.

• Journal of Welding and Joining
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• 제21권6호
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• pp.40-45
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• 2003

Steel members have advantages of resisting torsion and axial compression. In design, residual stresses at the welded joint of T-shape steel pipes are one of the most important points to be considered. In this paper, characteristics of residual stresses of welded joints are clarified by carrying out 3D non-steady heat conduction analysis and 3D thermal elastic-plastic FE-analysis. According to the results, the production mechanism of residual stresses at the welded joint of T-shape steel pipe is clarified. In this paper, circumferential stresses depended on thermal histories but axial and radial stresses were more dependent on geometrical shape than thermal histories. Residual stresses in the axial direction on the lower part of pipe member were tensile, controlled by geometrical shape. However, in case of middle part, residual stresses in all the directions were controlled by thermal histories.

• 한국해양공학회지
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• 제11권4호
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• pp.40-48
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• 1997

There are many research results as individual uni-axial tension creep test of heat-resisting materials. However, there are very few about the study on the high temperature creep test for the Initial Strain Method, and especially any study on it about the friction welded joints of SUH3 to SUH35. One of the important concerns is a reliable method of evaluating static creep properties. No reliable method seems available at present to evaluate or predict static creep properties. So, the reliable method to evaluate and predict them by the ISM and AE techniques was made.

• 한국생산제조학회지
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• 제20권6호
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• pp.740-744
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• 2011

Carbon-carbon composite material is the reinforced carbon fiber. Because of its high strength, elasticity and the excellent heat-resisting property in high temperature, carbon-carbon composite material has been used in many fields such as aerospace and automotive industries, etc. Especially, aircraft brake discs used at aerospace can be cracked due to its fatigue and vibration under various loading condition. This research is focused on the influence of the vibration of carbon-carbon composite material by using accelerometer with impact hammer excitation. And the change of vibration mode will be known by applying tensile loading test.

• Journal of Biosystems Engineering
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• 제23권2호
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• pp.187-194
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• 1998

This study was carried out to investigate mechanical properties o major part for agricultural machinery in Korea. The results are as follows ; 1. The mechanical Properties for heat resisting steel bars, alumium alloy castings, carbon steel for machine structural use, chromium molybdenum steels, high strength brass castings and carbon tool steels are proper for Korean standard. 2. The mechanical properties fir spring steels used to mould board, share of plow and blade of rotary are not suitable to Korean standard. Ⅰ think that a counterplan for quality rising is necessary such as supply of good quality materials and improvement of new materials in Korean agricultural machinery.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2003년도 유체기계 연구개발 발표회 논문집
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• pp.346-352
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• 2003

The study was performed to search on alternative material for turbopump parts made of Russian material by analyzing and comparing chemical and mechanical material properties. Iron base material was generally used for turbopump. This material can be categorized into stainless steel and heat resisting steel by quantity of additional elements. Each steel was also classified into austenite steel, ferrite steel, and martensite steel. Alternative materials for turbopump inducer, impeller and casing are chosen by JIS SUS 631 and 321 as a result of this study. Because the material of Russian turbopump turbine may be developed by Russia itself, alternative material can be hardly found. However, Inconel 718 for turbine material is thought to be proper in the aspect of hardness considering general use of this material for turbopump turbine in Japan and France.

• 한국안전학회지
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• 제26권5호
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• pp.27-32
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• 2011

Recently new technological development needs the advances in the fields of new materials. The most advanced design is not useful if new material's performance is not realized adequately for bearing the service loads and conditions. FGMs suggests the reasonable solution for the those requirements because of its wide range microstructure and the continuous constitutions. It's especially good for the heat-resisting components, piezoelectricity and aerocraft fields. However the fabrication and its experimental estimation methods have not been established because of its various freedom of material's properties. Therefore it is necessary to develope the fabrication method and estimation of strength and deformation. The experiments are conducted under a four point flexural test. According to results, this study shows that FGMs is well fabricated and the deformation and strain fields are expressed very well by digital image correlation method.