나노/마이크로 압입 시험에 의한 플라즈마 세라믹 용사코팅의 특성 평가

최세영(Se-Young Choi),채영훈(Young-Hun Chae),김석삼(Seock-Sam Kim) 한국트라이볼로지학회 2003 한국트라이볼로지학회 학술대회 Vol.36 No.-

The most controversial topics in plasma sprayed ceramic coating systems are recently mechanical properties such as bond strength, cohesive strength, toughness and so on. In this research, critical fracture load(Pc) and interface toughness(Ks) of four coatings materials were computed from the applied load, crack length and Young's modulus data which were measured by micro-vickers and nano indentation test. It is reasonable to consider the Pc value as comparison data of bond strength, and the Kc value, considering a trace of indent in the interface, was computed by a modified (E/H)I<SUP>½</SUP> ratio. In the case of the high loads (9.8N and 19.6N) in the Al₂O₃+13%TiO₂ coating, the critical point(Pco) at which the coating was broken was found. Also, used by a XRD phase analysis, we checked a change of coating' s properties, predicting a possible change of the phases in plasma sprayed coating.

정신분열병에 대한 리스페리돈의 효과 및 안정성

이민수,김용구,김영훈,연병길,오병훈,윤도준,윤진상,이철,정희연,강병조,김광수,김동언,김명정,김상훈,김희철,나철,노승호,민경준,박기창,박두병,백기청,백인호,손봉기,손진욱,양병환,양창국,우행원,이정호,이종범,이홍식,임기영,전태연,정영조,정영철,정인과,정인원,지익성,채정호,한상익,한선호,한진희,서광윤 大韓神經精神醫學會 1998 신경정신의학 Vol.37 No.1

연구목적 : 본 시험의 목적은 임상시험 시작전에 연구자들을 대상으로 PANSS Workshop을 통하여 PANSS, ESRS에 대한 국내에서의 표준화 작업을 구축하고 새로운 정신병 치료제인 리스페리돈의 효과와 안정성을 재확인하여 리스페리돈 사용에 대한 적정화를 이루는데 있다. 연구방법 : 1996년 4월부터 1996년 9월까지 국내 39개 대학병원 정신과에 입원중인 혹은 증상이 악화되어 입원하는 정신분열병 환자 377명을 대상으로 다시설 개방 연구를 시행하였다. 1주일간의 약물 배설기간을 가진후, 리스페리돈을 8주간 투여하였고, 기준점, 1주, 2주, 4주, 그리고 8주후에 평가되었다. 용량은 제1일에는 리스페리돈 1mg씩 1일 2회, 제2일에는 2mg씩 1일 2회, 제3∼7일에는 3mg씩 1일 2회 투여하였다. 이후 환자의 임상상태에 따라 임의로 증량할 수 있으며, 최대 일일 16mg을 초과하지 않도록 하였다. 추체외로 증상을 조절하기 위한 투약을 허용하였다. 임상증상 및 부작용의 평가는 PANSS(Positive and Negative Syndrome Scale), CGI(Clinical Global Impression) 그리고 ESRS(Extrapyramidal Symptom Rating Scale)을 사용하였다. 연구결과 : 377명중 343명(91%)이 8주간의 연구를 완결하였다. 치료 종결시점인 8주후 PANSS 총점수가 20% 이상 호전된 경우를 약물 반응군으로 정의할때, 약물반응군은 81.3%였다. 리스페리돈에 반응하는 예측인자로는 발병연령, 이전의 입원 횟수, 유병기간이 관련 있었다. 리스페리돈은 1주후부터 PANSS양성, 음성, 및 일반정신병리 점수상에 유의한 호전을 보여 효과가 빨랐다. CGI의 경우도 기준점에 비해 1주후부터 유의한 감소를 나타내었다. ESRS의 경우, 파킨슨 평가점수는 기준점과 비교해 투여 1주, 2주, 4주후 유의하게 증가되었다가 8주후 기준점과 차이가 없었다. Dystonia 평가점수는 1주후만 유의한 증가를 보였으며, dyskinesia 평가점수는 유의한 차이가 없었다. 혈압, 맥박수의 생명징후 및 일반 혈액학 검사, 생화학적 검사, 심전도 검사에서 유의한 변화는 없었다. 결 론 : 이상의 다시설 개방 임상 연구를 통해 리스페리돈은 정신분열병 환자에서 양성증상뿐만 아니라 음성증상 및 전반적인 증상에도 효과적인 것으로 사료된다. 보다 명확한 평가를 위해서는 다른 항정신병약물과의 이중맹검 연구가 필요할 것으로 생각되며, 또한 장기적 치료에 대한 평가도 함께 이루어져야 하겠다. Objective : The purpose of this study was to investigate the efficacy and safety of risperidone in the treatment of Korean schizophrenic patients. Method : This multicenter open study included 377 schizophrenic patients drawn from 39 university hospitals. After a wash-out period of 1 week, the schizophrenic patients were treated with risperidone for 8 weeks and evaluated at 5 points ; at baseline, and 1, 2, 4 and 8 weeks of treatment. The dose was increased from 2mg/day(1mg twice daily) to 6mg/day(3mg twice daily) during the first week and adjusted to a maximum of 16mg/day over the next 7 weeks according to the patient's clinical response. Medication to control extrapyramidal symptoms was permitted. The psychiatric and neurological status of the patients was assessed by PANSS, CGI, and ESRS scales. Results : 343(91%) of 377 patients completed the 8-week trial period. Clinical improvement, as defined by a 20% or more reduction in total PANSS score at end point, was shown by 81.3% of patients. The predictors of response to risperidone were associated older age, shorter duration of illness, fewer previous hospitalization. Risperidone had rapid onset of action ; a significant decrease of the total PANSS and three PANSS factor(positive, negative, general), and CGI was already noticed at the end of first week. For the ESRS, parkinsonism rating scores were significantly increased until week 4 comparing with baseline. Dystonia rating scores were significantly increased until week 1, and dyskinesia rating scores were not significantly changed during the study. Laboratory parameters including vital sign, EKG, hematological, and biochemical values showed no significant changes during the trial. Conclusions : This study suggests that risperidone is generally safe and effective against both the positive and negative symptoms in our group of patients.

일부 농촌지역 노인들의 인식기능에 관한 조사 연구

심운택,배일훈,오장균,조영채 충남대학교 의과대학 지역사회의학연구소 1991 충남의대잡지 Vol.18 No.1

For the purpose of promotion of mental health in the rural elderlies, we surveyed 506 elderlies by means of Mini-Mental State Examination(MMSE) for evaluation of cognitive functions. We assesed degree of cognitive function impairments and association between cognitive function and socio-environmental conditions. The results were as follows : 1. Proportion of severe and mild cognitive function impairments were increased as incresing age, and mean scores of MMSE became decreased significantly among them(P<0.001). 2. In female, rates of severe and mild cognitive function impairment were high and mean scores of MMSE were significantly lower than male(P<0.001). 3. In widow group, proportion of severe and mild cognitive function impairment were high and mean scores of MMSE were significantly low(P<0.001). 4. As decreasing familly numbers, proportion of severe and mild cognitive function impairment became high and mean scores of MMSE were significantly low(P<0.01). 5. In physical handicaped group, proportions of severe and mild cognitive function impairment were high and mean scores of MMSE were significantly low(P<0.001). 6. In low scores of physical ability group, proportions of severe and mild cognitive function impairment were high and mean scores of MMES were significantly low(P<0.001). 7. Most item-scores of MMSE were significantly correlated. 8. In stepwised multiple regression analysis, age, existence of physical disorder, sex and scores of physical ability were selected highly correlated variables and power of explanation was 0.1528.

급성충수돌기염으로 발현된 방선균증 2예

조진원,송진영,김창억,민영훈,최창순,우흥정,현인규,김종현,유기철,채승완,손진희 대한화학요법학회 2001 대한화학요법학회지 Vol.19 No.1

The Actinomyces species are normal flora of oral cavity and upper intestine characterized as gram-positive, non-spore-forming anaerobic or mjcroaerophilic rods. Actinomycosis is a chronic suppurative and granulomatous disease characterized by abscess, sinus, abundant granulation and mass. The appendix is the commonly involved site among abdominal actinomycosis. Abdominal actinomycosis is often difficult to diagnose before operation because of no reliable clinical features and infrequency of the disease. We report two cases of abdominal actinomycosis which were manifested as acute appendicitis. Those were detected Incidentally tv the pathologist after routine appendectomy. Both patients were successfully treated with appendectomy followed by proper antibiotics use.

Al₂O₃-40% iO₂ 용사층의 연구 (Ⅱ) : 마멸기구 모델링 modelling of wear mechanism

김우섭,오명석,채영훈 영남이공대학 1998 論文集 Vol.27 No.-

The wear behaviors of Al₂O₃-40%TiO₂ deposited on Al-alloy of casting(ASTM A356) by plasma spray against SiC ball have been investigated experimentally. Friction and wear tests are carried out at room temperature. The thickness of Al₂O₃-40%TiO₂ coatings indicated the existence of the optimal coating thickness. The columnar grain of coating will be fractured to achieve the critical stress. It is suggested that the mismatch of thermal expansion of substrate and coating play an important role in wear performance. Tensile and compressive of coating under thermo-mechanical stress may be occurred by the mismatch between thermal expansion of substrate and coating. This crack propagation above interface is observed in SEM.

Keratotic melanocytic nevus mimicking a seborrheic keratosis(초)

( Chae Young Lee ),( Jin Woo Hong ),( Ki Yeol Lee ),( Young Hun Kim ),( Ki Ho Kim ) 대한피부과학회 2010 초록집 Vol.48 No.10

A case of complex regional pain syndrome(초)

( Chae Young Lee ),( Jin Woo Hong ),( Ki Yeol Lee ),( Young Hun Kim ),( Ki Ho Kim ) 대한피부과학회 2010 초록집 Vol.48 No.10

A case of monocytic Leukemia cutis

Chae Young Lee,Ki Yeol Lee,Kyu Won Choi,Young Hun Kim,Ki Ho Kim 대한피부과학회 2009 대한피부과학회 학술발표대회집 Vol.61 No.1

A case of monocytic Leukemia cutis (초)

( Chae Young Lee ),( Ki Yeol Lee ),( Kyu Won Choi ),( Young Hun Kim ),( Ki Ho Kim ) 대한피부과학회 2009 초록집 Vol.47 No.10

Friction Behavior of Micro-scale Groove Surface Patterns Under Lubricated Sliding Contact

Chae Young-Hun Korean Tribology Society 2005 KSTLE International Journal Vol.6 No.2

Surface texturing of tribological applications is an attractive technology of engineered surface. Therefore, reduction of friction is considered to be necessary for improved efficiency of machines. The current study investigated the potential of textured micro-scale grooves on bearing steel flat mated with pin-on-disk. We discuss reducing friction due to the influence of sliding direction at surface pattern. We can indicate lubrication mechanism as a Stribeck curve, which has a relationship between the friction coefficient and a dimensionless parameter for the lubrication condition. It was found that the friction coefficient was changed by the surface pattern and sliding direction, even when surface pattern was the same. It was thus verified that micro-scale grooves could affect the friction reduction considerably under mixed and hydrodynamic lubrication conditions. The lubrication regime influences the friction coefficient induced by the sliding direction of groove pattern. The friction coefficient depends on a combination of resistance force and hydrodynamic.