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Mitsunobu 반응을 이용한 Ethyl 2-Fluoro-2-phenylsulfonylethanoate의 벤질화 반응
허선철,김대영 순천향대학교 기초과학연구소 1999 순천향자연과학연구 논문집 Vol.5 No.1
1-1'-(아조디카르보닐)-디피페리딘(ADDP)-트리부틸포스핀(TBP)을 이용한 Mitsunobu 반응을 통하여 에틸 2-플루오르-2-페닐술포닐에탄오에이트와 벤질알콜로부터 에틸 2-플루오르-3-페닐-2-페닐술포닐프로판오에이트를 비교적 높은 수율로 합성 하였다.
허선철,박영철,이동화,이광영,박원조 경상대학교 해양산업연구소 2002 해양산업연구소보 Vol.15 No.-
In this study, it is peformed to optimize important design variables of 3 dimensional GMI-36 Yoke which has a complicated shape. The design variables are a long and a short axis of an ellipse and parameters of upper part of Yoke and outer diameter of lower part of Yoke and the constraints are maximum stress and displacement. The weight of Yoke is minimized using Subproblem Approximation Method. The result is that 3.8% of total weight is reduced through this optimization and the feasibility of design compared with that of conventional model can be verified..
박영철,허선철,윤두표,강재욱 동아대학교 공과대학부설 생산기술연구소 1997 生産技術硏究所硏究論文集 Vol.2 No.1
Since the ceramic/metal joints at high temperature, the residual stress will develops during when it is cooled from bonding temperature due to remarkable difference of thermal expansion coefficient betwen ceramic and metal. Moreover, the edge of jointed interface makes singular stress field in the ceramic/metal joints and this singular stress field much influences on the strength of joints. In this study, the influence of residual stress, mechnical load and repeat thermal cycle were estimated in the ceramic/metal joints. According to this influence, the change of singular stress field was analyzed. The results are as follow : 1) Strength of joints was evaluated by the stress singularity index λ and the intensity K of singular stress field. 2) the stress singularity index λ and the intensity K of singular stress field also increase as adding temperature of thermal cycle and its number of cycle. 3) In the case of mechanical load, the influence of residual stress reduces since the difference(Δλ) of stress singular index between existence and inexistence of residual stress decreases in proportion to the increasing of tensile load.
FRONT SUSPENSION의 LOWER ARM에 대한 최적설계
박영철,윤두표,허선철,조용배 동아대학교 공과대학부설 생산기술연구소 1997 生産技術硏究所硏究論文集 Vol.2 No.1
LOWER ARM which jointed Independent Front Suspension is resulted in stress sidtribution analysis by using Finite Element Method. These datas represented in the condition of 8 loads and 3-type-section(I, H and H+I) type. On the basis of it, it is optimized shape and dimension fo LOWER ARM. The optimized performance shows that the H type of 3 types has an available strength and H´ section, which proved by H type, finds safety factor and yield strength in each case of load condition.
박원조,허선철,신동인 경상대학교 해양산업연구소 2002 해양산업연구소보 Vol.15 No.-
STS 304 has been developed with Nickel and Chromium containing about 8% Nickel and 18% Chromium. In case of STS 304 could be apply to ship hull and ship materials as well as various industries because it has a specific strength, high tensile strength and heat resistant. The experiments of mechanical properties and plain stress fracture toughness(J_IC) were carried out to obtain the characteristics of STS 304. Fracture strength tests were performed in accordance with the ASTM standard test method Standard Test Method for Plane-Strain Fracture Toughness of Metallic Materials (ASTM E8l3). The influence of thickness on the plane strain fracture toughness of this STS 304 steel was also investigated. The fractured specimens were examined by SEM.
SCM에 의해 제조된 금속기복합재료의 파괴인성 및 미끄럼마모 특성
이광영,박원조,허선철,신동인 경상대학교 해양산업연구소 2002 해양산업연구소보 Vol.15 No.-
AC4CH-based metal matrix composites with All_8B_40_33w reinforcement have been produced using squeeze casting method Metal matrix composite that is produced from matrix material AC4CH and inorganic binders Al_2O_3 and TiO_2 are added to the metal matrix composite for strength so binding among the whisker can take place. In this paper, an investigation was performed on frictional abrasion and the fracture toughness of AC4CH alloy reinforced with 20wt% aluminum borate whisker which contained a Al_20_3, TiO_2. The test of fracture toughness was using CT(half-size) specimen of thickness 12.5mm, width 25mm(ASTM E1820). To test for tribo a pin-on-disk machine and lubricant is used without paraffine 8.2CST at room temperature.
MoSi_2기 복합재료의 소결온도에 따른 미끄럼마모 특성
이광영,박원조,허선철,김형진,박성호 경상대학교 해양산업연구소 2002 해양산업연구소보 Vol.15 No.-
Molybdenum disilicide(MoSi_2) is considered to be a promising high temperature material for turbojet anhypersonic engines in aerospace and various industrial applications, because of a high melting point(2030℃),adequate density(6.3g/cm^3) and an excellent oxidation resistance. Mosi2 powder was evaluated from the variation of fabricating such as preparation temperature 1250℃, 1350℃ and 1500℃ respectively. Abrasion tester used a pin-on-disk type and a Si3N4 ceramic ball which used as machine structural materials. The test condition apply to load of 8kgf at 7.5rpm for 6 hours and the effect of hardness is also discussed. As a result of the tests, the friction coefficient was decreased with sintered MoSi_2 of increasing temperature but the function coefficient did not vary much for all specimens at all temperatures.
SCM에 의해 제조된 금속기 복합재료의 미끄럼마모 특성
이광영,박원조,허선철,박성호,허정원 경상대학교 해양산업연구소 2002 해양산업연구소보 Vol.15 No.-
AC4CH-based metal matrix composites with All_B_40_33w reinforcement have been produced using squeeze casting method. Metal matrix composite that is produced from matrix material AC4CH and inorganic binders SiO_2, Al_20_3 and TiO_2 are added to the metal matrix composite for strength so binding among the whisker can take place. In this paper, To test for tribo a pin-on-disk machine and lubricant is used without paraffine 8.2CST at room temperature which is 40℃. As the results of this study, the tribological properties of each specimen are more improved then AO4CH. The variation of coefficient resistance is more stable at the AC4CH, TiO_2, but the variation rates are higher at the inanimate binder
저방사화강(JLF-1)의 고온 피로균열진전거동에 관한 연구
박원조,정재욱,허선철,허정원 경상대학교 해양산업연구소 2002 해양산업연구소보 Vol.15 No.-
The objective of this study is to investigate life and fatigue crack propagation in the Reduced Activation Ferritic steel(RAFs) JLF-1. Crack growth rate tests on compact tension specimen of thickness 12mm were conducted by using sinusoidal waveform. Compact tension specimens were used and crack growth rate da/dN and stress intensity factor range ΔK were analyzed concerning to the R value of 0.1, 0.3 and 0.5 In order to find out the value of ΔK, load amplitude constant method was applied by the standard fatigue testing method describes in ASTM E647-95a. The effects of stress ratio and specimen size on the fatigue crack growth propagation for JLF-1 steel were discussed within the Paris law. As the result of this study, fatigue crack growth rate increased with in creasing the load ratio, Consequently, fatigue crack propagation of half size specimen was similar to those of full size specimen at room temperature. Also, there was no difference between base metal and weld metal at room temperature and high temperature.(400℃)
온도 변화에 따른 DW-100 용접재의 기계적특성에 관한 연구
박원조,정재욱,변상열,허선철,유재환 경상대학교 해양산업연구소 2002 해양산업연구소보 Vol.15 No.-
In recent years, the studies of mechanical property of weld materials were one of the most important basic test of our welding indursty. The used specimen in this study is weld metal of DW-100 flux cored wire which is using for flux cored are welding and one type of flux cored wires were used in this test. This paper is based on the quality of the mechanical property of welding material under the different temperture, test temperature of each weld metal is from RT to 900℃ and temperature gap is 100℃ for each weld metal. It is particularly important to assess tensile properties and each specimen was examined using by the following methods; Reduction of area rate, Tensile strength test, and observation of SEM. All tensile tests were performed in accordance with the ASTM standard test method, tension testing of metallic materials (ASTM I-8). This study proves that the mechanical properties of until 400℃ were good as the increasing temperature compare with mechanical properties of RT. As the results of this study, the tensile strength of 300℃ was higher than other weld metals. Also the reduction of area rate was the lowest at 300℃ according to the previous test results. Consequently, this weld metal is a good substitute for the existing welding materials until 400℃ which is used in the development of welding industries today.