[건강기획] 발목 통증, 방치하면 평생 ‘삐끗’

서동현 넥스트미디어 2015 넥스트 이코노미 Vol.- No.136

總輸膽管 側方成形術을 施行한 膽石症患者에 關한 臨床的 硏究

徐東鉉 충남대학교 의과대학 지역사회의학연구소 1979 충남의대잡지 Vol.6 No.2

An analytic review of the clinical records of 24 cases who had been made by-pass surgery of common bile duct among 73 cases of cholelithiasis at Department of Surgery, Chungnam National University Hospital from April, 1974 to April, 1979. The results were obtained as follows : 1. The incidence of cholelithiasis was following orders : common bile duct stone : 54.8%, gallbladder stone : 46.6% and intrahepatic stone : 15.1% 2. The incidence was hight in 30-49 years and mean age was 46.6 and males predominated over females by 1.9 : 1 in cholelithiasis. 3. Operative procedures were as follows : choledochoduodenostomy : 18 cases(75%), choledochojejunostomy : 5 cases (20.8%), and sphincteroplasty : 1 case(4.2%). 4. The indications for by-pass surgery of common bile duct were as follows : intrahepatic stone : 11 cases(45.8%), dilated common bile duct with multiple muddy stone : 8 cases(33.3%), residual or recurrent stone : 4 cases(16.7%), and common bile duct stone with stenosis of sphincter : 1 case(4.2%). 5. The incidence was hight in 30-49 years and males predominated over females by 1.7 : 1 in operated patients with by-pass surgery of common bile duct. 6. The prominent symptoms and signs were pain in right upper quadrant of abdomen, tenderness, nausea and vomiting, jaundice, fever and chillness, indigestion and hepatomegaly etc. in order of frequency. 7. The rate of positive findings was 63.6% in oral cholecystogram or intravenous cholangiogram preoperatively. 8. Postoperative complications were wound infection in 2 cases(8.3%). respiratory infection in 2 cases(8.3%) residual stone in common bile duct in 1 case(4.2%) etc. choledochoduodenostomy was lesser incidence of complication than choledochojejunostomy. 9. The operative mortality was 4.2% and severe jaundice and hepatic coma were the cause of death.

AcciMap, STAMP, FRAM을 이용한 반응기 세척 작업 중 화재 사고 분석

서동현,배계완,최이락,한우섭,Seo, Dong-Hyun,Bae, Gye wan,Choi, Yi-Rac,Han, Ou-Sup 한국안전학회 2021 한국안전학회지 Vol.36 No.4

Representative systematic accident analysis methods proposed so far include AcciMap, STAMP, and FRAM. This study used these three techniques to analyze a fire accident case that occurred during routine manufacturing work in a domestic chemical plant and compared the results. The methods used different approaches to identify the cause of the accident, but they all highlighted similar causal factors. In addition to technical issues, the three accident analysis methods identified factors related to safety education, risk assessment, and the operation of the process safety management system, as well as management philosophy and company culture as problems. The AcciMap and STAMP models play complementary roles because they use hierarchical structures, while FRAM is more effective in analyses centered on human and organizational functions than in technical analyses.

지역 다지점 통신 서비스용 Ka-band MMIC 전력 증폭기 설계

서동현,김남영 광운대학교 신기술연구소 1998 신기술연구소논문집 Vol.27 No.-

지역 다지점 통신 중계기에 사용되는Ka-Band(26.7~27.5GHz)대역의 단일칩 초고주파 집적 회로 평형 전력 증폭기를 본 논문에서 설계하였다. 능동 소자로는 고속 전자 이동도 트랜지스터가 사용되었으며 on-wafer상에서 측정을 하기 위하여 설계한다. 칩 크기는 6.5×3.5mm^2로 예상되며, 입출력단의 반사손실을 감소시키기 위해 lange coupler를 사용하였다. 설계된 평형 전력 증폭기는 27.45dBm의 출력 전력과 20.45dB의 전력 이득, 그리고 24.05dB의 선형 이득을 나타내었으며. 입출력 반사 손실은 최대 -20.7dB와 -20.8dB의 특성을 보인다. A Monolithic Microwave Integrated Circuit(MMIC) Ka-band(26.7 ~27.5GHz) balanced power amplifier for LMCS was designed in this paper. Pseudomrphic High Electron Mobility Transistors (P-HEMTs) were used to design MMIC power amplifier for RF on-wafer measurement with a Ground-Signal-Ground(GSG) Pattern and its chip size is expected 6.53.5mm^2. The balanced power amplifier was designed to decrese the input and output return loss using lange coupler This designed balanced MMIC power amplifier resulted in 27.45dBm output power. 20.45dB power gain and 24.05dB linear gain. Input return loss(S_11) and output return(S_22) are maximum -20 7dB and -20.8dB.

서울지역 지역계수가 적용된 직산분리 모델의 성능 비교

서동현,김혜진 한국태양에너지학회 2019 한국태양에너지학회 논문집 Vol.39 No.3

Decomposition models are essential in TMY development and solar energy system design. Up until recently, only a few decomposition model related researches are implemented in Korea due to lack of measured direct normal solar irradiance. In contrast, numerous researches have been conducted in various countries, and some quasi-universal composition models have been recommended by several papers. In this research, three decomposition models – Watanabe model, Reindl-2 model and Engerer1 model - are selected and their site-fitted coefficients are developed using measured direct normal solar irradiance in Seoul. R-squared, RMSE, MBE of the site-fitted models are compared with the case of original coefficients and then each other. The comparison result shows that the Reindl-2 model with site-fitted coefficients is best suitable for Seoul. Further researches will be conducted to find the best model using more various measured data of Korean cities and site-fitting methods.

에너지다소비건물의 에너지사용특성 분석에 관한 연구

서동현 한국퍼실리티매니지먼트학회 2013 한국퍼실리티매니지먼트학회지 Vol.8 No.1

Characterizing building energy consumption at the level of nationwide per building type is mandatory data-base for developing building energy policies, energy efficient technologies, low or zero energy buildings, etc. This DB is also very valuable for developing benchmark building model for detailed building energy simulation and building energy labelling program of Korean government which uses computer simulation tool. However, there is no such a DB that is well organized for building energy management. None the less, Energy Consumption Survey (KEEI, 2012) is the most available DB to obtain energy consumption features of national building stock. The DB only for Large Buildings (defined by government that use over 2,000 TOE per year) is re-defined for building energy labelling program’s EUI definition with some additional analysis such as end-user break-down and monthly energy use. The result shows that high-rise apartment building and university campus are satisfying national building energy labelling program and the others are out of criteria by using over 700 kWh/m2-yr. Relative to the various and vast data base in the Energy Consumption Survey, useful data for characterizing building energy consumption is very limited.

전자의 속도 Overshoot 현상이 단자 전류에 주는 영향

서동현,박영준,민홍식 대한전자공학회 1995 대한전자공학회 학술대회 Vol.1995 No.1

III-V족 화합물 반도체 MESFET 연구동향

서동현,김남영,김종헌 한국전기전자재료학회 1998 전기전자재료 Vol.11 No.8

세라믹 담체를 이용한 생물반응기의 악취원인물질 제거

서동현,오길용,김대근 한국냄새환경학회 2020 실내환경 및 냄새 학회지 Vol.19 No.2

This study was conducted to evaluate the applicability of a carrier media with natural minerals as packing material in a biofilter to remove odor-causing compounds. The carriers were prepared by mixing powdered zeolite, barley stone, and clay. They have a pellet type with a length of 5m m to 10 mm, 3.2 m2/g of a specific surface area, and 0.04 cm3/g of a pore volume. The adsorption capacity and the biodegradation by biomass formation on the media were experimented with toluene and ammonia as the test compounds. The carrier possessed the ability to adsorb toluene and ammonia. The adsorption capacity of toluene and ammonia at the inlet concentration of 100 ppmv was 58 g/g and 96 g/g, respectively. In the biofilter using the carrier as the packing material, the biofilter performances were different depending on the supply of moisture and liquid-nutrient. The critical loading was found to be 33.13 g/m3/hr for toluene removal and 6.5g /m3/hr for ammonia removal even when no nutrients were supplied. The proposed material has been confirmed to be capable of adsorbing inorganic and organic compounds, and can be effectively applied as packing materials for the biofiltration.

알칼리 활성화 모르타르의 메타카올린 치환율에 따른 특성

서동현,형원길,Seo, Dong-Hyeon,Hyung, Won-Gil 한국건축시공학회 2016 한국건축시공학회지 Vol.10 No.4

The aim of this study is to look into the metakaolin replacement ratio of blast furnace slag based alkali activated slag mortar and its mechanical characteristics according to changes in stimulant concentration. Metakaolin has high fineness, and therefore the fluidity becomes lower as the replacement ratio becomes higher. So in this study, a sufficient value of mixing water was provided to secure fluidity for the characteristic experiment, and a different W/B was derived for each specimen in order to make the fluidity identical. A characteristic experiment was conducted according to the mol concentration of NaOH, which was used as the mixing water that affects fluidity. Additionally, compressive strength measurement, observation of inner microstructure through SEM, acid resistance experiment, and neutralization resistance was conducted. The results of this study revealed that for a high concentration NaOH solution to have even fluidity, a high W/B is necessary, and the functions were enhanced, not degraded. 본 연구의 목적은 고로슬래그 베이스 AAS 모르타르의 메타카올린 치환율과 자극제 농도의 변화에 따른 역학적 특성과 내구성에 대하여 알아보는 것이다. 메타카올린은 분말도가 높아서 치환율이 높아질수록 유동성이 많이 저하되기 때문에 본 연구에서는 충분한 NaOH 수용액를 가하여 시공성을 확보한 상태에 실험을 진행하였다. 따라서 모든 시험체의 시공성을 동일하게 하는 각기 다른 Ws/B를 도출하였고, 이에 따라 시공성에 영향을 미치는 NaOH 수용액의 몰 농도별 특성에 대한 실험을 진행하였다. 또한 압축강도 측정실험, SEM을 통한 내부 미세구조 관찰, 내산성 실험 실험을 진행하였다. 본 연구 결과 메타카올린 치환율이 높은 배합은 Ww가 많이 필요로 하였지만, 그에 따른 성능 저하는 나타나지 않으며 오히려 우수한 역학적 내구적 성능을 보여주었다. 또한 [6M]보다 [8M]농도의 NaOH 자극제를 사용했을 때 메타카올린 치환 효과가 극대화 되었다.