항공기용 유압 시스템 신뢰도 및 정비도 분석 프로세스 고찰

한창환,김근배,Han, ChangHwan,Kim, KeunBae 한국시스템엔지니어링학회 2016 시스템엔지니어링학술지 Vol.12 No.1

An aircraft must be designed to minimize system failure rate for obtaining the aircraft safety, because the aircraft system failure causes a fatal accident. The safety of the aircraft system can be predicted by analyzing availability, reliability, and maintainability of the system. In this study, the reliability and the maintainability of the hydraulic system are analysed except the availability, and therefore the reliability and the maintainability analysis process and the results are presented for a helicopter hydraulic system. For prediction of the system reliability, the failure rate model presented in MIL-HDBK-217F is used, and MTBF is calculated by using the Part Stress Analysis Prediction and quality/temperature/environmental factors described in NPRD-95 and MIL-HDBK-338B. The maintainability is predicted by FMECA(Failure Mode, Effect & Criticality Analysis) based on MIL-STD-1629A.

우울증에 있어서의 생물학적 지표 ( I)

한창환 한림대학교의료원 1987 人間科學 Vol.11 No.7

당뇨병성 동결 견에서 Vascular Endothelial Growth Factor의 역할

한창환,김원유,최융섭,최동원,김정만 대한정형외과학회 2002 대한정형외과학회지 Vol.37 No.1

Purpose : To investigate the role of VEGF (vascular endothelial growth factor) and macrophage cells in the pathogenesis of diabetic frozen shoulders. Materials and Methods : Five diabetic frozen shoulders which were resistant to conservative treatment were involved in this study. Synovial tissue was obtained during arthroscopic adhesiolysis. The synovial tissue of the shoulders from cadava dominators who had no history of shoulder joint disease was used for the control study. Immunohistochemical staining was performed with polyclonal antibodies against VEGF and CD68 macrophage/synovial antigen. Results : Injection and hypertrophy of the synovium and thickening of the capsule were noted in all diabetic frozen shoulders. Strong immunostaining to VEGF and CD68 was observed in all diabetic frozen shoulders, whereas the control specimens showed little staining. Conclusion : From these results it would be postulated that the VEGF, synthesized and secreted by macrophage/synovial cells of the diabetic frozen shoulders stimulate regional angiogenesis which leads to synovitis and fibrosis could be one of the leading factors in the pathogenesis of frozen shoulders in diabetic patients. 목 적 : 당뇨병성 동결 견의 병인을 알아보고자 VEGF (vascular endothelial growth factor) 및 대식세포의 역할을 연구하는데 있었다. 대상 및 방법 : 보존적 요법에 반응하지 않은 당뇨병성 동결 견에서 관절경하 박리술 시행시 조직을 얻을 수 있었던 5예의 활액막 조직과 동결 견 병력이 없는 2예의 장기 기증자의 정상 견관절에서 얻은 활액막 조직을 이용하여 VEGF 및 CD68 (ma-crophage marker)에 대한 면역 조직 화학적 염색을 실시하여 비교 관찰하였다. 결 과 : 당뇨병성 동결 견의 관절경 소견상 충혈되고 증식된 활액막과 비후된 관절막을 관찰할 수 있었으며, VEGF 및 CD68에 대한 면역 조직 화학적 염색 결과 중등도 이상으로 강하게 염색되었으나, 대조군에서는 의미 있는 염색 소견은 관찰되지 않았다.

우울증에서의 생물학적 지표(II) 신경전달물질과 그 대사물

한창환 한림대학교의료원 1989 人間科學 Vol.13 No.11

새 정부의 건설 규제 개혁 과제

한창환,진광현,최상근,이재식,최상호,이의섭,백영권,강운산 한국건설산업연구원 2008 한국건설산업연구원 연구보고서 Vol.- No.-

Primary pancreas extranodal NK/T cell lymphoma

한창환,김태현,최금하,전형구 대한내과학회 2019 대한내과학회 추계학술대회 Vol.2019 No.1

항불안제의 부작용

韓昌桓 대한의학협회 1995 대한의학협회지 Vol.38 No.10

우울증 아형들의 이해

한창환,류성곤,Han, Chang-Hwan,Ryu, Seong Gon 대한생물정신의학회 2001 생물정신의학 Vol.8 No.1

우울증으로 고통받는 많은 환자들에서 보이는 다양항 양상과 다양한 경과를 자주 접하면서 분류를 어떻게 하여야 임상적으로 유용한가 의문을 가지게 된다. 이에 저자들은 우울증의 아형 평가의 필요성과 평가도구들을 문헌을 통하여 고찰하였다. 원래부터 이들이 이질적인 집단으로 구성되어 있는지, 하나의 유전적 소인이 있어 개인에 따라서 병의 진행 시기에 따라서 여러 우울증의 spectrum으로 표현되는 것인지 문제가 제기되어 왔지만, 현재로서는 분명히 알 수 없다. 저자들은 먼저 "우울증 스펙트럼" "양극성 우울과 단극성 우울이 공통의 하나의 유전적 인자를 가지는가" "양극성 스펙트럼 장애"등 강한 주장들이 있어 문헌 고찰을 통해서 알아보았다. 그리고, 최근 생물학적인 연구로부터 나온 세로토닌 관련 우울증 가설을 알아보았다. 이 우울증 가설(SeCA depression)은 조기 모성 분리 혹은 모성 박탈 같은 유년시절의 부정적 경험, 불안, 공격성, co-rtisol 증가, cortisol flattening, DST 양성, 스트레스 사건, CRF 상승, 5HIAA저하 등을 연결하여 우울증의 역동을 쉽게 설명하였고 생물-심리-사회적 접근을 가능하게끔 하는 우울증의 모델이다. 둘째로 고전적인 생물학적 지표 즉 DST, TRH 자극 검사, 및 뇨 MHPG 검사 결과에 따르는 우울증 아형을 구분하고 특징을 살펴보았고 이들의 역사적이고 임상적인 의미를 알아보았다. 그밖에 APOE epsilon 4 allele, 기질-성격이론(Temperament Character Inventory : TCI) 심박동 변이도(heart rate variability : HRV) 같은 요인들을 비롯하여 잘 알려진 증상이나 진단으로 분류된 아형들을 조사하여 임상적인 의미를 찾아보았다. The debate about whether depressive disorders should be divided into categories or arrayed along a continuum has gone for decade, without resolution. In our review, there is more evidence consistent with the spectrum concept than there is with the idea that depressive disorders constitute discrete clusters marked by relatively discontinuous boundaries. First, "depression spectrum", "is there a common genetic factors in bipolar and unipolar affective disorder", "threshold model of depression" and "bipolar spectrum disorder" are reviewed. And, a new subtype of depression is so called SeCA depression that is a stressor-precipitated, cortisol-induced, serotonin-related, anxiety/aggression-driven depression. SeCA depression is discussed. But, there is with the idea that depressive disorders constitute discrete subtypes marked by relatively discontinuous boundaries. This subtypes of depressive disorder were reviewed from a variety of theoretical frames of reference. The following issues are discussed ; Dexamethasone suppression test(DST), TRH stimulation test, MHPG, Temperament Character Inventory(TCI), and heart rate variability(HRV).

탄소섬유 복합재료 사각튜브의 압추에너지 흡수 특성

한창환,김근택,이종원,최윤호,Han, Chang-Whan,Kim, Keun-Taek,Lee, Jong-Won,Choi, Youn-Ho 한국항공우주연구원 2002 항공우주기술 Vol.1 No.2

본 연구는 탄소섬유 복합재료 사각튜브의 압축 에너지 흡수 특성을 실험적으로 규명하였으며, 유한요소해석을 통해서 그 특성을 예측하였다. 압축 속도는 0.003mm/sec 와 0.3mm/sec로 하여 사각튜브에 가하였으며, 적층각 별로 실험을 하여 각각에 대한 압축 에너지 흡수 특성인 최대 압축하중과 평균하중을 찾았다. [0/90]₄와 [0/±45/90]₂의 특정 적층각을 가지는 사각튜브에 대해 유한요소해석을 수행하여 최대 압축하중을 예측하였다. 유한요소모델은 좌굴해석을 통해서 나온 형상과 원래 형상을 중첩하였으며, 해석방법은 Tsai-Wu criteria를 사용하였다. 실험으로부터 최대 압축하중은 인 사각튜브에서 나타났고 평균 압축하중은에서 나타났으며, 특정각을 가지는 사각튜브에 대한 최대 압축하중 예측은 실험과 거의 일치하였다. Crush energy characteristics of graphite/epoxy square tubes are experimentally studied. Effect of the ply orientation on the peak load and the average load is investigated by applying compressive load on the top of the composite square tubes under the stroke control with crosshead speed of 0.003mm/sec and 0.3mm/sec. in addition to the experimental survey, the finite element analysis is used to estimate the peak load of the composite square tubes with [0/90]₄ and [0/±45/90]₂. The first buckling mode of the tube is superimposed to the perfect geometry and the distributed compressive load is applied on the top of the tubes. The applied compressive load that make Tsai-Wu criteria equal to one is regarded as the peak load of the tubes. The experimental data shows that the square tube with [45/-45]₄ has the highest peak load and the square tube with [60/-60]₄ has the average sustained load. The measure peak load of the composite tubes with [0/90]₄ and [0/±45/90]₂agree well with the estimated peak load using the finite element analysis.

정신분열병(精祥分裂病) 환자(患者)의 사회적(社會的) 지지망(支持網) 분석(分析)

한창환,김광진,석재호,Han, Chang-Hwan,Kim, Kwang-Jin,Suk, Jae-Ho 한국정신신체의학회 1996 정신신체의학 Vol.4 No.2

This study was designed to evaluate the social support network of schizophrenic patients. 64 schizophrenic patients being treated as out-door patient were compared with 30 neurotic control patients. Schizophrenics were divided into positive, subpositive, subnegative and negative subgroups by present symptom and social network of both schizophrenics and control group were evaluated. The results are as follows: 1) Social network of schizophrenics was smaller than that of control group. Size of social network of schizophrenics was 10.6 and that of control group was 23.5. 2) In both kin and nonkin, social network of schizophrenics was smaller than that of control group. Of the kin, schizophrenics were more supported by wife or husband, father, and mother, but were less supported by brother, son and other relatives. 3) There was no difference in the kin or nonkin or total supporters between the four subgroups of schizophrenics. But, subgroup of schizophrenics which was divided as having negative symptom had smaller network than control group in active formal and informal supporters. 4) When divided into 4 support areas, schizophrenics was remarkably less supported in emotional, instrumental and appraisal support area than control group, but there was no difference in the informational support areas. 5) Compared with control group, schizophrenics more often mentioned parent and ten often mentioned nonkin supporter as the one that is most important to him. 6) Schizophrenics had smaller cluster and less leisure activity than control group. Subgroup of schizophrenics who was divided as having negative symptom had less frequency of leisure activity than other subgroups.