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곽승근,천재민,박남숙,박상은,박수진,윤환중,김삼용,조덕연 충남대학교 의학연구소 2003 충남의대잡지 Vol.30 No.2
Megaloblastic anemias are disorders caused by impaired DNA synthesis and chara-cterized by the presence of megaloblastic cells. Clinical data on these disorders in Korea are limited. The aim of this study was to analyze clinical characteristics of megaloblastic anemias caused by vitamin B12 deficiency. We identified 40 cases who were diagnosed as megaloblastic anemia from January 1993 to December 2002 in a retrospective study on the basis of chart review. We investigated the annual distribution of diagnosed patients, clinical manifestations and response to treatment. 19 cases were complicated with a previous total gastrectomy(gastrectomy group) and 21 cases had no history of surgical operation(non-gastrectomy group). The most common presenting complaint was generalized weakness. The median age at diagnosis was 7(range: 38-79) years in non-gastrectomy group. The mean pos-toperative duration was 7(range: 4-25)years in group of total gastrectomy and mean level of serum vitamin B12 was lower than 100 pg/mL in both group. Peripheral blood revealed thrombocy-topenia, macrocytic anemia and hypersegmented neutrophil in all cases. After treatment of pareliteral vitamin B12, Their clinical symptoms and hematologic findings improved except two patients who had bone marrow with lower cellularity. Cobalamin replacement after total gastrectomy is still missing. Diagnoses are made too late in a population of patients, resulting in irreversible neurological sequale, and we suggest that Pernicious anemia seems not to be very rare in Korea.
후드를 이용한 협소 터널 미기압파 감소 효과에 대한 수치적 연구
윤수환(Su-Hwan Yun),김병열(Byung-Yeol Kim),구요천(Yo-Cheon Ku),이동호(Dong-ho Lee),권혁빈(Hyeok-Bin Kwon),고태환(Tae-hwan Ko) 한국철도학회 2005 한국철도학회 학술발표대회논문집 Vol.- No.-
The train entry into a tunnel generates a strong compression wave in the tunnel The high amplitude of compression wave causes high pressure gradients that are responsible for both the aural discomfort of passengers and the impulsive acoustical wave called the mira-pressure wave. This paper provides a numerical study on effects of hood for micro-pressure wave reduction. An axisymmetric numerical solver, considering the crass-sectional area of Korean Tilting Train express, is used for a transient flow field in the tunnel Results show that the micro-pressure wave is able to be reduced by a hood. In this results, the maximum reduction of micro-pressure wave is shown at 2L(length), 1.35D(diameter) hood around 56% against the non-hood case.
비례 유압 릴리프 밸브 내 오일오염입자제거 제어 알고리즘 검증
천수환 ( Su-hwan Cheon ),박진감 ( Jin-kam Park ),장민호 ( Min-ho Jang ),이진웅 ( Jin-woong Lee ) 한국농업기계학회 2021 한국농업기계학회 학술발표논문집 Vol.26 No.1
비례 유압 릴리프밸브는 입력전류에 비례하여 압력을 제어하는 밸브로써 주로 변속기의 유압 클러치 구동에 활용된다. 변속기가 동작할 때 유압오일은 크기가 다양한 금속, 비 금속성분으로 이루어져 있는 오염입자들과 섞이게 된다. 오일오염입자들이 밸브 바디와 스풀사이에 끼이게 되면 스풀의 거동이 불안정해지고 압력제어성이 저하되며 트랙터의 유압 클러치에 심각한 손상을 유발하게 된다. 본 연구는 오일오염입자가 비례 유압 릴리프밸브 바디와 스풀사이에 끼이는 현상을 해결하기 위한 제어 로직개발의 기초연구로서 수행되었다. 오일오염입자를 제거하기 위하여 짧고 강한 밸브 스풀의 움직임을 일으키기 위한 솔레노이드 밸브의 전류 제어 로직을 개발하였으며 실제 오염원을 밸브에 주입하는 시험을 통해 로직의 효용성을 검증하였다. 로직을 개발하기 위하여 프로그램은 MATLAB/SIMULINK를 활용하였다. 전류를 제어하기 위해 PWM 제어를 이용하였으며 갑작스런 전류 변화에 의한 클러치 면압의 변화를 최소화하기 위해 Duty비를 조정하였다. 검증방법은 정상적인 비례 유압 릴리프밸브의 Command 신호 대비 압력 반응성을 기준 삼아 오염원을 주입한 비례 유압 릴리프 밸브의 안정성을 판단하였으며, 제어로직을 적용하여 효과의 유무를 확인하였다. 시험결과로 제어로직을 적용했을 때 전류에 따른 밸브압력의 반응이 안정해졌고 오일오염입자가 제거되었다고 판단하였다. 향후 연구에서는 비례 유압 릴리프밸브의 안정성을 위해 제어로직을 최적화시키는 것이 바람직할 것으로 판단되며 클러치의 구동과 같이 고려하여 검증할 계획이다.
보건의료 R&D 연구성과 활용·확산을 위한 특허맵 분석 및 활용방안 연구
전수환(Su-Hwan Cheon),이경민(Kyung-Min Lee),김미경(Mi-Kyoung Kim),제영태(Young-Tae Je),신상훈(Sang-Hun Shin),김명환(Myung-Hwan Kim),김동석(Dong-Seok Kim),박성호(Seong-Ho Park),김기택(Gi-Tae Kim),곽정애(Jung-ae Kwak),전혜경(Hye-Kyoung 한국생물공학회 2013 KSBB Journal Vol.28 No.6
Translational research (TR) as high quality research can accelerate collaboration strongly between biotechnology-based researchers and clinical-research experts for overcoming diseases. TR facilitates basic science translated to clinical efficacy and effectiveness from bench (basic science) to bedside (clinical practice) for the enhancement of human health. Disease-oriented TR programs were defined as unilateral, bilateral and multilateral TR in this patent performance analysis. Patent performance was measured in a R&D project on Health and Medical Technology to enhance the productivity of R&D investment on disease-oriented TR in Health Technology (HT). Patent Map (PM) analysis and Bibliometrics were conducted to collect information for the assessment of research patents of TR programs. Futhermore, PIAS (Patent Information Analysis System) and Thinklear programs were applied for quantitative and qualitative analysis successfully. These indicate that multi-dimensional analysis of patent performance for disease-oriented TR could promote the connection of R&D-IP (Research and Development-Intellectural Property) and R&BD (Research and Business Development) supporting system significantly.
전자식 비례 압력제어밸브 내 오일 오염 입자 제거 제어 알고리즘 검증
천수환(Su Hwan Cheon),박진감(Jin Kam Park),장경제(Kyoung Je Jang),심성보(Sung Bo Sim),장민호(Min Ho Jang),이진웅(Jin Woong Lee) 유공압건설기계학회 2021 드라이브·컨트롤 Vol.18 No.4
An electro proportional pressure control valve is mainly used to control the clutch of an agricultural tractor’s automatic transmission. During transmission, the operating, hydraulic oil is mix with many kinds of contaminants. The contaminants can be trapped between the valve body and spool of the proportional pressure control valve leading to abnormal operating conditions and finally critical damage to the transmission hydraulic system. The present study aimed to verify the valve control algorithm as a basic study of developing control logic that removes contaminants between the spool and the body of the proportional pressure control valve. To develop the algorithm, MATLAB/SIMULINK was used. PWM method was used to control the applied solenoid coil current. The effectiveness of the algorithm was verified by comparing the actual pressure of the normal valve with the actual pressure of the abnormal valve. Based on the present study findings, when the algorithm was applied, the response of the valve pressure according to the current became stable and oil contaminated particles were removed. In the future study, the control algorithm will be optimized for the stability of the proportional pressure reducing valve, and it will be verified in consideration with the driving of the clutch.