질소이온주입에 의한 Al 합금의 조직변화 및 내식성 향상에 관한 연구

엄기원(Khey W. Urm),윤주선(Joo S. Yoon),한전건(Jeon G. Han),연윤모(Yun M. Yeon) 한국진공학회(ASCT) 1995 Applied Science and Convergence Technology Vol.4 No.2

고에너지 (50~200 keV)로 가속된 이온을 모재표면에 물리적으로 투입하므로써 표면의 조성 및 조직을 변화시키는 공정인 이온주입기술을 이용하여 경량고강도소재로 각광받고 있는 Al2218 합금의 내식성 향상을 연구하였다. 질소이온주입은 DuoPIGatron 이온원을 사용하여 가속전압 100 keV, 조사량 1×10^(l7) ions/㎠~5×10^(17) ions/㎠의 조건으로 행하였으며 Al 합금의 열화를 방지하기 위하여 시편온도를 60℃ 이하로 유지하였다. 질소이온 주입재의 내식성 평가를 위하여 35% NaCl 용액에서 양극분극시험 및 5% NaCl 용액에서 염수분무시험을 행하였다. Auger Electron Spectroscopy와 Transmission Electron Microscopy을 이용하여 표면의 질화물형성 여부를 조사하였으며, Scanning Electron Microscopy을 이용하여 부식된 표면을 관찰하였다. Al2218 합금에 질소이온을 주입한 결과 표면에 미세한 AlN 석출물을 형성하였으며 이러한 질화물형성에 의해 공식(pitting) 발생을 억제하고 부식전류밀도를 감소시켜 내식성이 향상되었다. The micro structure change and corrosion behavior of nitrogen implanted Al2218 aluminium alloy has been investigated. Nitrogen implantation was carried out by using Duo-PIGatron ion source at an accelerating energy of 100 keV to total dose of 1×10^(17) ions/㎠ and 5×10^(17) ions/㎠ with current density of 40 μA/㎠. The temperature of substrate was maintained below 60℃ during implantation. The structure change of implanted layer was analyzed by AES and TEM and the corrosion behavior was evaluated by anodic polarization test in 3.5% NaCl solution and salt spray test in 5% NaCl solution. Nitrogen implantation produced fine precipitates of aluminium nitride and fairly reduced corrosion rate as well as enhanced corrosion potential. The improvement of corrosion resistance becomes effective with increasing total nitrogen ion dose. The enhancement of corrosion resistance was observed to be closely associated with AlN formation as well as irradiation damage which promotes passivation and higher pitting potential.

안드로이드 접근 제어 정책 연구 동향 분석

엄서정 ( Seo-jung Urm ),조영필 ( Yeong-pil Cho ) 한국정보처리학회 2023 한국정보처리학회 학술대회논문집 Vol.30 No.1

PT와 NPT 구조를 가진 3300V HVIGBT 스위칭 특성 비교 연구

엄기주(Kee-Ju Urm),서범석(Burn-Seok Suh),현동석(Dong-Seok Hyun) 전력전자학회 1999 전력전자학술대회 논문집 Vol.1999 No.7

이 논문은 3300V 정격의 PT와 NPT HVIGBT의 스위칭 특성을 비교하여 제시한다. 실제적인 응용을 고려하여 hard 스위칭 조건에서 실험하여 얻어진 데이터 수치들을 보인다. 이 비교 평가가 보다 나은 스위칭 특성들을 얻기 위한 기반이 될 수 있을 것이다.

만성 간질환 환자의 삶의 질 평가 (논평)

엄상화 ( Sang Hwa Urm ) 대한간학회 2007 Clinical and Molecular Hepatology(대한간학회지) Vol.13 No.1

GMS-5 위성의 가시자료를 이용한 동아시아 지역의 에어로솔 광학두께 추정

엄영대(Young-Dae Urm),손병주(Byung-Ju Sohn) 한국기상학회 2005 대기 Vol.15 No.4

韓國의 國際팩토링決濟方式의 問題點에 關한 硏究

嚴珖烈 건국대학교 1998 학술논문집 : 건국대 대학원 Vol.47 No.1

International commercial transaction have performed generally through the instrument known as the L/C which has proven effective In setting accounts between exporters and importers. From the viewpoint of cost and process, however, the L/C transaction incurs considerable burden to traders, particulary small and medium enterprises. The objective of this study is to set an academic theory on international factoring transaction in Korea and to expand trade volume threrby after determining beneficial aspects of international factoring transactions for exports as well as imports. Merits for exporters are as follows: First, it can reduce the risk of payment default in the part of importers because the exporter factors guarantee the payment. Second, business activities can be expanded as working capital is received in advance from exporters factors. Third, more buyers can be induced as exporter factors furnish information about goods and markets. Finally, and most importantly, the international factoring transaction should be newly provided as an indepentant export-import transaction in Foreign Trade Act.

Modeling, simulation and structural analysis of a fluid catalytic cracking (FCC) process

Kim, Sungho,Urm, Jaejung,Kim, Dae Shik,Lee, Kihong,Lee, Jong Min Springer-Verlag 2018 Korean Journal of Chemical Engineering Vol.35 No.12

미용업 종사자들의 피부, 호흡기 및 근골격계 자각증상에 관한 유병률

이종태,박봉진,엄상화,김성준,강동묵,손혜숙,정귀원,강민숙,박성희 大韓産業醫學會 1999 대한직업환경의학회지 Vol.11 No.3

Objectives: Present study was conducted to evaluate work-related symptom prevalence among hairdressers. Methods: Exposed group comprised 184 employee employed 73 hair salons in 6 district of Pusan city, and non-exposed group comprised 119 people living recent apartments. A trained interviewer interviewed them with organised questionnaire which included dermatologic, respiratory and musculo-skeletal symptoms. Results : Prevalence of hand eczema was 28.3% in exposed group, and 5.8% in non-exposed group. Adjusted odds ratio for age and atopy history was 4.30(2.34-7.93). Prevalence of respiratory symptom (coughing) in exposed group was 22.1%, and 9.4% for non-exposed group. Adjusted odds ratio for coughing which was adjusted for age, smoking and atopy history was 2.76(1.32∼5.78). Prevalences of musculo-skeletal symptoms among exposed group were neck(59.9%), shoulder(76.6%), upper back(41.2%), lower back(72.2%), arm and elbow(31.3%), wrist(44.2%), finger(35.0%), leg(71.1%). Adjusted Odds Ratios for musculo-skeletal symptoms which was adjusted for age were neck 2.13(1.29∼3.51), shoulder 2.52(1.50∼4.24), upper back 1.71(1.01∼2.88), lower back1.78(1.06∼2.99), arm and elbow 3.10(1.62∼5.94), wrist 2.09(1.23∼3.57), finger 4.83(2.41∼9.68), leg 3.46(2.07∼5.79). Conclusions : These results show that employees in hair salon are likely to have high risk for work-related dermatologic, respiratory and musculo-skeletal symptoms and diseases. Hence, prevention methods from those work-related diseases are required to be developed. Also, the scope of occupational and environmental medicine should be expanded to service area including hairdressers.

서울 일부 지역 사무직 근로자들의 고혈압 유병률 및 고혈압 근로자들의 정밀 검사에 대한 조사

정귀원,엄상화,최순석,김정호,이종태,전진호,이채언,배기택 인제대학교 1997 仁濟醫學 Vol.18 No.1

근로 기준법 및 근로자 건강진단 실시 지침(노동부)에 의거 매년 건강진단을 받아야 하는 서울 일부 지역 근로자 1,480명(남:1.028명, 여:452명)을 조사 대상으로 고혈압의 유병률을 조사한 결과 남녀에서 각 18.8%, 6.0%였으며, 연령별로 구분한 고혈압의 비교 위험도는 40세 이상이 40세 미만보다 약 2배 높았다. 고혈압 정밀 대상자(160명)의 심전도와 안저 검사 이상율은 두항목 모두에서 정상군에 비해 높은 비율을 보였으며, 검사 항목들 간의 상관 관계에서 수축기 혈압은 이완기 혈압과, 혈청 콜레스테롤은 비만도, 중성 지질과 유의한 양(陽)의 상관 관계를 보인반면, 고밀도 지단백질은 중성 지질과 혈청 콜레스테롤과 음(陰)의 관계를 시현하였다. To determine the prevalence rate of hypertension by aging and hypertension-related factors, the authors carried out the survey of the on 1480 clerical employees and the results of detailed clinical examination (Lab data, echocardiography, fundoscopic finding) on 160 persons with hypertension in Seoul area from Jan 1, 1993 through Dec 31, 1993 The results are as follows : 1.The prevalence rate of hypertension among total subjects was 11.9% (male : 18.8%, female:6.0%), and it was gradually increasing with aging in male. 2.A prevalence rate of hypertension in subjects over 40 years old was about two times as large as that under the age of 40. 3.The prevalence rates of hypertension in obesity group(120% and over of standard body weight) and normal group(under 109% of standard body weight) were 14.1% and 6.1%. 4.The mean concentration of total cholesterol, HDL and triglyceride level in the hypertensive group were 223.7 37.1 mg/dl, 42.6 9.7 mg/dl. 197.4 61.0 mg/dl, respectively. 5.The abnormality rate in echocardiographic finding in the hypertensive group was 62.5%, and it was gradually increased as blood pressure increased. 6.The abnormality rate in fundoscopic finding of the hypertensive group was 42.5%, and it was gradually increased as systolic blood pressure increased. 7.The positivity rates of urinary protein in uristix were 1.5%(male:1.3%, female:1.7%) in normal group and 2.6% (male : 2.4%, female : 2.7% ) in hypertensive group. 8.There were positive correlation between systolic blood pressure and diastolic blood pressure; total cholesterol and index of obesity, triglyceride: and negative correlation between HDL and total cholesterol and triglyceride.

근로자 건강진단 결과 분석과 활용 실태 조사

정귀원,엄상화,최순석,정수진,배기택,이정열 인제대학교 1998 仁濟醫學 Vol.19 No.2

산업안전보건법(근로자건강진단 실시규정) 및 의료보험법에 의거 1997년 1월 1일 부터 12월까지 서울지역 근로자 516명(남:381명, 여:135명)을 대상으로 일반건강진단시 실시한 각 검사 항목의 평균치는 모두 정상 범위에 있었고, 남녀별 비만도는 여자에서 정상율이 높았으며, 특히 여자 20대에서 93.8%로 가장 높았다. 고혈압의 경우 남녀별 평균 혈압은 116.8/78.3 mmHg, 109.9/71.6 mmHg, 유병율은 수축기 혈압의 기준치에 의하면 6.8%, 5.9%, 이완기 혈압에 의하면 16.0%, 8.9%로 남자에서 모두 높게 나타났다. 혈액검사 기준치에 따른 이상자율은 남녀별로 각각 혈색소 6.2% 5.2%, 적혈구 용적치 1.6%. 10.5%, 적혈구수 1.6%, 10.5%, 백혈구수 4.9%, 10.4%, 혈소판수 5.1%, 10.5%, AST 3.2%, 4.5%, ALT 22.3%, 5.9%, rGTP 8.1%, 12.6%, 총콜레스테롤 6.7%, 8.2%, 트리글리세라이드 22.8%, 14.1%, BUN 3.5%. 14.3%, Creatinine 1.5%, 28.0%, 공복시 혈당치 4.3%, 74%이었으며, B형간염 표면항원 양성율은 남녀별로 5.2%, 3.7%였고, 표면항체 양성율은 67.8%, 69.1%였다. 건강진단 결과에 따른 질병 유소견자들에 대한 사후 관리는 일반 질병 유소견자의 경우 근무중 치료가 60%(18명)로 가장 높았으며. 추적 정밀검사 8명(26.7%), 입원 요양치료 2명(6.7%), 금주, 금연, 식이습관 조절, 규칙적 운동 등 기타 의학적 조치 1명(3.3%)의 순으로 나타났고, 여자의 경우 근무중 치료와 추적 정밀검사가 6명중 각 3명씩 차지하였다. 질환 요주의자의 사후 관리에서는 남녀 모두 추적 정밀검사가 각각 23명(58.9%), 8명(47.0%)으로 가장 많았고, 다음이 근무중 치료 9명(23.0%), 5명(29.4%), 금주, 금연, 식이습관 조절, 규칙적 운동 등 기타 의학적 조치가 7명(20.0%), 4명(23.5%)순이었다. To survey the follow-up services and results of health examination among white collar workers who received health examination at Seoul Paik hospital, the authors analyzed some labaratory findings of blood(hemoglobin, hematocrit, RBC, WBC, platelet, AST ALT. r-GTP, tonal cholesterol. triglyceride, BUN, creatinine, fasting blood sugar), obesity index, blood pressure and follow-up services according to results of health examination of them. The subjects were 516 persons(male 381, female : 135) in total and study period was from Jan 1, 1997 to Dec 31, 1997. 1.Abnormal rates of obesity(120% and over standard body weight) among total subjects were 17.0% in male and 4.7% in female, and prevalence rate of hypertension were 6.8% in male, 5.9% in female by systolic pressure and 16.0% in male, 8.9% in female by diastolic pressure and it was gradually increasing with aging in total subjects. 2.The mean values of hematologic findings were all within normal limit but there were significant differences at WBC, Platelet. r-GTP, Total cholesterol, triglyceride, BUN, fasting blood sugar in male and hematocrit, total cholesterol in female between each age groups.(p<0.05) 3.Positive rate of Hepatitis type B surface Antigen and Antibody were 5.2%, 67.8% in male 3.7%, 69.1% in female each other. 4.Follow-up services of the subjects who were in abnormal conditions by health examination among white collar workers were insufficient to a view of practical management, those were treatment while on duty, putting on protectors and other recuperation, follow up study, a change of working places, shortening of working hours and restriction and prohibition of service.