잔류응력을 고려한 SS400재의 피로특성에 관한 연구

최병희,이종범,정장만,장경천,최병기 朝鮮大學校 機械技術硏究所 2007 機械技術硏究 Vol.10 No.2

In this study is about the fatigue characteristics which appears in the welding residual stress field. The welding residual stress takes place mostly at the portion where SS400 materials are automatical welded. The effects of the welding residual stress in the growth and propagation of fatigue crack, so as to study the fatigue behavior in the welding residual stress field. The results, in case of the load range is constant, as the stress ratio is changing to 0.1, 0.33. 0.5 the propagation life is constant but the growth life decreases. And than, when maximum load or minimum load is constant, as the stress ratio increases the growth life and propagation life increase. The fatigue crack propagations rate da/dN appears to accelerate when the stress intensity factor range △K is less than 15MPa-m^(1/2). The growing and propagation fatigue crack in the welding residual stress field is similar to original specimen after being passed the original residual stress field.

蓄熱用 TMA 包接化合物의 熱物性에 關한 實驗 硏究(Ⅰ)

최영범,한영옥,하옥남,김병철,김진흥 조선대학교 동력자원연구소 1996 動力資源硏究所誌 Vol.18 No.2

This paper presents the test-tube experimental results of thermal properties of TMA clathrate compounds for latent heat storage applications. The results are : ⅰ) subcooling in TMA clathrate compound is the lower than water, ⅱ) Phase change temperature in TMA clathrate compound is the higher than water. ⅲ) Latent heat of 25wt% TMA clathrate compounds of 220.4kJ/㎏K appear to be maximum. ⅳ) Comparing with water, volume of TMA clathrate compounds decreased as the phase change. ⅴ) TMA clathrate compounds precipitated because of increase of density as phase change. Thus, TMA clathrate compounds are found to be the promising compounds for the heat storage from the viewpoint of thermal property.

수소 자기 공명 분광 영상으로 확인된 후두엽성 중첩성 복합 부분 간질에 의한 뇌신경 세포의 손상

서범천,김옥준,김현숙,최철희,김서현,이병인 대한신경과학회 1999 대한신경과학회지 Vol.17 No.1

Methotrexate 치료를 받고 있는 활동성 류마티스 관절염 환자에서 etanercept의 유효성과 안전성에 관한 연구

최병렬,강태영,정청일,이혜순,엄완식,김태환,전재범,유대현,배상철 대한내과학회 2004 대한내과학회지 Vol.66 No.5

목적 : 류마티스 관절염을 앓고 있는 한국인 중에 기존 DMARDs로 치료 실패하였고, 고정용량의 MTX를 복용하고 있는 환자들에 있어서 etanercept의 유효성과 안전성을 평가하고자 하였다. 방법 : 기존 DMARDs로 치료 실패한 활동성 류마티스 관절염 환자 76명을 대상으로 하여 단일군, 공개시험을 하였다. 대상 환자들은 고정용량의 MTX를 복용하면서 etanercept 25 mg을 1주일에 두 번 피하 주사하였으며 12주간 투여하였다. 유효성은 ACR 20, ACR 50,조조강직 시간으로 평가하였고, 약제의 안전성은 이상반응 등으로 평가하였다. 결과 : 대상 환자는 총 76명으로 평균 연령은 45.2세, 남자 5명, 여자 71명이었다. 84.4%인 54명이 12주째에 ACR 20을 만족하였고, 53.1%인 34명이 12주째에 ACR 50을 만족하였다. 조조 강직 시간은 치료 전 203.3분에서 치료 12주째 42.6분을 평균 74.5% 호전되었다. 가장 흔한 이상반응은 주사부위 반응이었다. 이외에도 상기도 감염, 오심, 안면부종 등이 발생하였으나 심각한 부작용은 없었다. 결론 : etanercept는 효과적이고, 안전한 류마티스 관절염 치료 방법이며 특히 MTX치료에도 불구하고 활동성인 류마티스 관절염에 기대되는 치료라고 할 수 있다. Background : This study was performed to investigate the efficacy and safety of etanercept in active rheumatoid arthritis patients with stable dose of methotrexate in Korean. Methods : In a 12 week, single arm, open trial, we assigned 76 patients with active rheumatoid arthritis who had an inadequate response to disease-modifying antirheumatic drugs. Patients received twice-weekly subcutaneous injections of etanercept 25 ㎎ while containing to receive methotrexate at a stable dose of 7.5~25 ㎎ per week. The clinical response was defined as the percent improvement in disease activity according to the criteria of the American Collage of Rheumatology (ACR) at 12 weeks. Results : Etanrecept led to significant improvements in disease activity and was safe and well tolerated. At 12 week, 84.4% of the patients receiving 25 ㎎ of etanercept achieved a 20% ACR response, and 53.1% of those receiving etanercept achieved a 50% ACR response. The most common adverse event was injection-site reaction. Other advanse events were upper respiratory infection, nausea, and facial edema, but there were no serious adverse events associated with etanercept. Conclusion : In active rheumatoid arthritis patients, etanercept was safe, well tolerated, and provided rapid clinical improvements.

순수 Ti 용접재의 기계적 특성 및 피로크랙 성장특성에 관한 연구

최병희,이종범,정장만,장경천,최병기 朝鮮大學校 機械技術硏究所 2007 機械技術硏究 Vol.10 No.2

In this study, fatigue fracture often occurs due to the fatigue crack in the machine and welding structure and this is the result of severe operational environment, operational condition, and design condition caused by the large scaled and light weighted machine and structure in recent days. Therefore, safety and reliability should be secured to prevent the fatigue fracture of machine and structure, and the use of titanium has been increased in the metal material for the safety and reliability. The purpose of this thesis was to investigate the welding characteristics and fatigue crack growth characteristics of titanium, commonly using power station, aircraft and ship. The experimented material was TIG welded in order to look over the characteristics according to the notch position and compare with other material. The results, at the same welding condition, 4 pass specimen which had the smallest number of welding pass had the highest tensile strength with 51kgf/㎟ and the tensile strength of 4 pass specimen was 10% higher than the one of 7 pass specimen, and its elongation reduced about 30%. The initial fatigue crack growth characteristic is slower in this order, boundary zone < welding zone < HAZ < base metal. Especially boundary zone's growth speed is slower about 30 times than base metals.

膨脹率이 一定한 超音速 노즐흐름에 있어서 非平衡 凝縮과 傾斜衝擊波

권순범,최태민,김병지 慶北大學校 1990 論文集 Vol.49 No.-

In the present study the case of expansion of moist air through a supersonic nozzle of constant expansion rate, which behaves similar to that of wet steam, was adopted. The effect of noneqilibrium condensation on the oblique shock wave generated by placing the wedge into the supersonic part of the nozzle was investigated. Furthermore, the variation of the condensation onset Mach number with the initial stagnation supersaturation, the relationship between noneqilibrium condensation zone and incident point of the oblique shock wave, the varation of angles of incident and reflected shock waves due to the variation of initial stagnation supersaturation, and the relationship between the height of Mach stem and initial stagnation supersaturation are discussed.

재발성 호흡기 유두종증의 임상양상과 보조 치료의 유용성

성명훈,최병윤,진정욱,성원진,박범정,노종렬,김대우,원태빈,김광현 대한이비인후과학회 2001 대한이비인후과학회지 두경부외과학 Vol.44 No.12

Serratia marcescens Purine Nucleoside Phosphorylase의 생합성에 대한 글리옥실산의 대사적 역할

신종란,방선권,최병범 한국식품영양학회 1999 韓國食品營養學會誌 Vol.12 No.1

최소 배지에 여러 퓨린 분해 대사 산물을 첨가하여 배양시킨 Serratia marcescens ATTC 25419 세포 추출물에서 purine nucleoside phosphorylase(PNP)의 활성을 조사한 결과, 구아노신은 대조군에 비해 효소의 활성을 5∼15mM에서 60% 이상 감소시켰고, 이노신은 7∼15mM에서 30% 정도 감소시켰으나 0.1∼1mM에서 효소의 활성을 원래대로 회복시켰다. 아데노신, 히포크산틴 및 크산틴도 5∼15mM에서 효소의 활성을 40∼50%정도 감소시켰으나 0.1∼0.5mM에서는 원래대로 회복시켰다. 한편, 요산은 효소의 활성을 0.5mM에서 20% 증가시킨 반면 15mM에서 80% 감소시켰다. 요산의 최종 분해 산물인 글리옥실산도 효소의 활성을 0.5mM에서 20% 증가시킨 반면 3∼15mM에서 30∼50% 정도 감소시켰다. 5mM 농도의 이노신, 히포크산틴 및 요산을 동시에 첨가했을 경우 효소의 활성을 20% 정도 감소된 반면, 이노신과 요산, 세 퓨린 분해 대사 산물은 각각 0.5mM씩 동시 첨가했을 경우는 각각 22, 33%씩 증가시켰다. 이 결과는 낮은 농도 (0.5mM)의 글리옥실산이 S. marcescens purine nucleoside phosphorylase (PNP)의 활성을 증가시키고 고 농도의 글리옥실산은 감소시키는 것을 나타내기 때문에 퓨린 분해 대사 과정에서 글리옥실산이 PNP 생합성의 조절 역할을 하는 것으로 분석된다. The effects of purine catabolites in growth media on the Serratia marcescens purine nucleoside phosphorylase activity were examined. The enzyme activity was decreased above 60% by guanosine (5 to 15mM). The enzyme activity was decreased approximately by 30% in the presence of high concentrations of inosine (7∼15mM), but was not affected at low concentration of inosine (0.1∼1mM). The enzyme activity was decreased approximately by 40∼50% in the presence of high concentrations of adenosine, hypoxanthine, and xanthine (5∼15mM), but was not affected at low concentration of adenosine, hypoxanthine, and xanthine (0.1∼0.5mM). However, the enzyme activity was increased by 20% with low concentrations of uric acid (0.5mM), but was decreased by 80% with high concentrations of same purine catabolite (15mM). Also, the enzyme activity was increased by 20% with low concentration of glyoxylate (0.5mM), final degradative product of uric acid , but was decreased by 30∼50% with high concentrations of glyoxylate (3∼15mM). The enzyme activity was decreased approximately by 20% by the simultaneous addition of inosine, hypoxanthine and uric acid at 5mM each, whereas it was increased by 22 and 33% by the combination of inosine and uric acid, three purine catabolites at 0.5 mM, respectively. These data suggest that S. marcescens purine nucleoside phosphorylase is positively regulated by a glyoxylate concentration, and then may play a regulatory role in a purine catabolism.

경동맥 스텐스의 조기결과

심원흠,홍범기,최동훈,김선호,김동익,김승민,이도연,장병철 대한순환기학회 1998 Korean Circulation Journal Vol.28 No.1

이면성 및 도플러 심초음파도를 이용하여 진단한 선천성 거대 좌회선지-좌심실 관동맥루

진승원,박준철,이영중,유병현,박현옥,김용주,윤호중,김재형,홍순조,최규보,권종범,원용순,박건 대한순환기학회 2000 Korean Circulation Journal Vol.30 No.4