SM45C용접부에서 회전굽힘시험에 의한 피로 및 파단면의 특성

이용복,Lee, Yong-Bok 한국생산제조학회 2010 한국생산제조학회지 Vol.25 No.3

SM45C steel rods using generally for machine components were selected and welded by butt-GMA welding method for this study. And then they were studied about characteristics of fatigue behavior and fracture surfaces by rotary bending test. Fatigue strength in weld zone present highly in order of the boundary between deposited metal zone and heat affected zone, deposited metal zone, heat affected zone. The region of infinite life by Haigh diagram present highly in order of the boundary between deposited metal zone and heat affected zone, deposited metal zone, heat affected zone. Fatigue cracks in unnotched specimens of base metal and weld zone introduce simultaneously from extensive out-side of circumferential cross-section and propagate to the other side indicating beach markings and dimples according to consolidation of fatigue cracks. Fatigue cracks in all of notched specimens introduce simultaneously in out-side of circumferential cross-section by high stresses and propagate to center of it indicating beach markings.

나프록센의 비선형 체내동태에 미치는 페노바르비탈의 영향

이용복,채명애,고익배 ( Yong Bok Lee,Myung Ae Chae,Ik Bae Koh ) 한국약제학회 1997 Journal of Pharmaceutical Investigation Vol.27 No.2

N/A In order to elucidate the effect of phenobarbital (PB) on the nonlinear pharmacokinetic behavior of naproxen (NAP), we compared the dose dependent hepatic intrinsic clearance, biliary excretion and protein binding of NAP in control rats to those in the PB-pretreated rats which were intraperitoneally pretreated with PB sodium (75 ㎎/㎏) once a day for four days. NAP was injected via femoral (1.5 ㎎/㎏) and portal(0.25, 0.5, 1.5, 15 and 30 ㎎/㎏) vein to the control and PB-pretreated rats, respectively. And also. we measured the plasma free fraction of NAP with the equilibrium dialysis method and the biliary excreted total amounts of NAP in both rats. Plasma free fraction of NAP was decreased in lower concentration than 150 ㎍/㎖ of NAP due to PB pretreatment. In higher concentration, however, plasma free fraction was increased. These in vitro results suggest that the total protein concentration was increased but the total binding capacity of NAP to protein was decreased by PB-pretreatment. The total plasma clearance and the hepatic intrinsic clearance of NAP had similar values in both groups, respectively. And, both clearances of NAP were significantly increased by PB-pretreatment. Even though the plasma free fractions of NAP in both groups were constantly remained within the concentration range according to the increase of administration dose, the hepatic intrinsic clearances of NAP were significantly increased in both groups with the increased dose. And, the biliary excreted total amounts of NAP were significantly increased by PB-pretreatment at the lower dose, but decreased at the higher dose. These in vivo results suggest that NAP represents the uncommon nonlinear pharmacokinetic behavior that the hepatic intrinsic clearance was enhanced with the increased dose, and that PB enhances further the hepatic intrinsic clearance of NAP with the increased dose due to its enzyme induction effect.

회전체 동역학 및 Tribo 요소의 연구동향

이용복,Lee, Yong-Bok 한국유체기계학회 2007 한국유체기계학회 논문집 Vol.10 No.1

SS330 용접재에서 재분포 잔류응력 및 균열닫힘영향을 고려한 파로거동에 관한 연구

이용복,정진성,조남익,Lee, Yong-Bok,Jeong, Jin-Seong,Jo, Nam-Ik 대한기계학회 1996 大韓機械學會論文集A Vol.20 No.7

In this study residual stress in weldment was considered about the effect on the fatigue propagation and about the effect of redistribution of residual stress. Then, fatigue tests were conducted by the center notched specimens machined with welded plate. The residual stress and its redistribution after the crack growth were measured by the magnetizing stress indicator and hole-drilling method. Fatigue crack propagation was estimated by the specimens having residual stress redistributed after the cracks growth and having the effects of crack closure. Crack growth rates were predicted and compared with experimental results. It had been found that the predicted crack propagation rates have a good agreement with experimental results when the redistribution of residual stress was considerd.

천문학의 발생과 발전과정

이용복,Lee, Yong-Bok 한국과학기술단체총연합회 1998 과학과 기술 Vol.31 No.10

랫트에 있어서 페노바르비탈 전처리가 딜티아젬의 생체내 동태에 미치는 영향

이용복,고익배,이민화,Lee, Yong-Bok,Koh, Ik-Bae,Lee, Min-Hwa 한국약제학회 1992 Journal of Pharmaceutical Investigation Vol.22 No.3

The influence of phenobarbital (PB) pretreatment (75 mg/kg/day, i.p. for 4 days) on the pharmacokinetics of diltiazem (DTZ) and its metabolite, desacetyldiltiazem (DAD), was investigated in rats. DTZ was injected via femoral (3 mg/kg) or portal (10 mg/kg) vein to the control and PB-pretreated rats. DAD was also injected separately via femoral (3 mg/kg) vein to both groups of rats. The intrinsic hepatic plasma clearance of DTZ was found to be significantly increased (6.8-fold) by the PB pretreatment. However, the fraction of an intravenous DTZ dose converted to DAD $(F_mi)$ was only slightly (6%) increased and calculated metabolic rate constant of DTZ to DAD was not affected by the pretreatment. On the other hand, plasma free fraction of DTZ was increased (1.8-fold) from $4.24{\pm}0.25%$ to $7.45{\pm}0.54%$ by the pretreatment. However, the l.8-fold increase in the free fraction of DTZ would not explain the 6.8-fold increase in the hepatic intrinsic clearance of DTZ. Therefore, the increase in either the hepatic blood flow or the metabolism other than to DAD was expected as the probable mechanism(s) of the increased hepatic clearance of DTZ. Sequential metabolism of DAD to further metabolites, however, would be a more potential cause of the apparently unchanged metabolism of DTZ to DAD by the PB-pretreatment.

공공기관의 입장에서본 AI

이용복,Lee, Yong-Bok 한국과학기술단체총연합회 1987 과학과 기술 Vol.20 No.11

압연 및 용접방향이 같은 맞대기 용접강판의 하중방향에 따른 피로균열 진전특성

이용복,김성엽,오병덕,Lee Yong-Bok,Kim Sung-Yeup,Oh Byung-Duck 대한용접접합학회 2005 대한용접·접합학회지 Vol.23 No.6

Most of the welding steel plate structures have complicated mechanical problems such as rolling directional characteristics and residual stresses caused by manufacturing process. For the enhancement of reliability and safety in those structures, therefore, a systematic investigation is required. SS400 steel plate used for common structures was selected and welded by FCAW butt-welding process for this study, and then it was studied experimently about characteristics of fatigue crack propagations with respect to rolling direction and welding residual stress of welded steel plates. When the angles between rolling direction and tensile loading direction in base material are increased, their ultimate strength not show a significant difference, but yielding strength are increased and elongations are decreased uniformly. It is also shown that fatigue crack growth rate can be increased from those results. When the angles between welding bead direction and loading direction in welded material are increase, fatigue crack growth rate of them are decreased and influenced uniformly according to the conditions of residual stress distribution. In these results, it is shown that the welded steel plate structures are needed to harmonize distributed welding residual stress, rolling direction and loading direction fur the improvement of safety and endurance in manufacture of their structures.

시메티딘이 간혈류량에 미치는 영향 - Rat에 있어서 Indocyanine Green의 체내 동태를 중심으로 -

이용복,고익배,Lee, Yong-Bok,Koh, Ik-Bae 한국임상약학회 1993 한국임상약학회지 Vol.3 No.2

The influence of cimetidine pretreatment(100mg/kg, single i.p.) on the hepatic blood flow was investigated using pharmacokinetic parameters of indocyanine green(ICG) in the rat on the basis of hepacc perfusion-limited model. ICG(1mg/kg) was respectively administered via femoral and portal vein to the control and to the cimetidine-pretreated rats. The rate constant K12, K20 and the systemic clearance(CLt) of ICG were significantly(p<0.05) decreased ill the cimetidine-pretrea-to(B rats, but no significant diffirences were observed in hematocrit and liver weight. The biliary excretion rates of ICG were also decreased regardless of the route of administration in the cimetidine-pretreated rats. And also the hepatic blood flow in rats was decreased about $16\%$ by cimetidine. It may be concluded that the decreased hepatic blood flow with cimetidine mainly contributed to the decreased hepatic uptake and the decreased systemic clearance of ICG.

기계적 프레스 접합의 최적접합조건에 관한 연구

이용복,김태윤,정진성,최지훈,Lee, Yong-Bok,Kim, Tae-Yun,Jeong, Jin-Seong,Choe, Ji-Hun 대한기계학회 2000 大韓機械學會論文集A Vol.24 No.3

Mechanical press joining has been used in sheet metal joining processes because of its simple process and possibility of joining dissimilar metals, such as steel and aluminum. The strength of mechanical press joining varies with joining conditions. The optimum joining conditions considering tensile-shear and peel-tension strength have to be established to assure the reliability in the joining strength. Therefore, optimization of joining conditions has been investigated for improving joining strength of sheet metal. It is possible to obtain optimum strength from improvement on the joining strength of peel-tension mechanical press joint under multiaxial stress states.