PMMA 유기 게이트 절연막의 농도와 두께에 따른 특성

유병철,공수철,신익섭,신상배,이학민,박형호,전형탁,장영철,장호정,Yoo, Byung-Chul,Gong, Su-Cheol,Shin, Ik-Sub,Shin, Sang-Bea,Lee, Hak-Min,Park, Hyung-Ho,Jeon, Hyung-Tag,Chang, Young-Chul,Chang, Ho-Jung 한국반도체디스플레이기술학회 2007 반도체디스플레이기술학회지 Vol.6 No.4

The MIM(metal-insulator-metal) capacitors with the Al/PMMA/ITO/Glass structures were manufactured according to various PMMA concentration of 1, 2, 4, 6, 8 wt%. The lowest leakage current and the largest capacitance were found to be 2.3 pA and 1.2 nF, respectively, for the device with 2 wt% PMMA concentration. The measured capacitance of the devices was almost same values with the calculated one. The optimum film thickness was obtained at the value of 48 nm, showing that the capacitance and leakage current were 1.92 nF, 0.3 pA at 2 wt%, respectively. From this experiment, the PMMA gate insulator films can be applicable to the organic thin film transistors.

크롬 취급 사업장의 작업환경 및 근로자 폭로 실태에 관한 연구

유병철,손병철,전진호,손혜숙,한용수,이채언,정운,Yu, Byung-Chul,Son, Byung-Chul,Jun, Jin-Ho,Han, Yong-Soo,Son, Hye-Sook,Lee, Chae-Eun,Jeong, Woon 대한예방의학회 1994 예방의학회지 Vol.27 No.3

For the purpose of providing the basic data for health management of workers who are exposed to chromium and for improving the quality of working environment, the authors evaluated blood and urinary level of chromium, the occupational history. AST, ALT, Hb, Hct, nasal specular examinaton on 287 workers who have been dealed chromium compounds in 56 manufacturing Industries of five types, that is, 38 metal plating services(plating),4 manufacture of other fabricated metal products (fabricated metal product), 5 manufacturing of dyestuff(dyestuff), 6 dressing and dyeing of leather(leather), 3 others(manufacture of pottery and ceramic househod wares, motor vehicles, electronic valves and tubes and other electronic components) and also measured the level of chromium in air from February to October 1993. The results were as follows ; 1. The utilized type of chromium compounds was the hexavalent state in plating fabricated metal product dyestuff, leather and the trivalent state in .other, and atmosperic chromium concentration as geometric mean was $0.0138mg/m^3(0.001{\sim}0.068mg/m^3)$ in plating, $0.0115mg/m^3(0.006{\sim}0.015mg/m^3)$ in fabricated matal product, $0.068mg/m^3(0.002{\sim}0.019mg/m^3)$ in dyestuff, $0.0083mg/m^3(0.002{\sim}0.028mg/m^3)$ in leather $0.0039mg/m^3(0.003{\sim}0.005mg/m^3)$ in other by the type of industry and it exceeded TLV-TWA ($0.05mg/m^3$) in five (13.6%) of plating services. 2. The geometric mean of chromium in blood was $1.54{\mu}g/dl(0.10{\sim}3.62{\mu}g/dl)$ in Plantng, $0.94{\mu}g/dl(0.27{\sim}2.82{\mu}g/dl)$ in fabricated metal product, $0.51{\mu}g/dl(0.10{\sim}3.25{\mu}g/dl)$ in dyestuff, $0.87{\mu}g/dl(0.15{\sim}8.00{\mu}g/dl)$ in leather, $0.55{\mu}g/dl(0.20{\sim}2.28{\mu}g/dl)$ in other by the type of industry(p<0.001). 3. The geometric mean of chromium in urine was $14.47{\mu}g/l(6.90{\sim}28.00{\mu}g/l)$ in planting, $4.63{\mu}g/l(0.24{\sim}43.00{\mu}g/l)$ in fabricated metal product, $5.93{\mu}g/l(1.00{\sim}33.00{\mu}g/l)$ in dyestuff, $11.09{\mu}g/l(0.80{\sim}48.00{\mu}g/l)$ in leather, $12.41{\mu}g/l(10.10{\sim}41.00{\mu}g/l)$ in other by the type of industry(p<0.001). 4. As the result of nasal specular examination, twenty four cases (8.4%) of nasal septal perforation among 287 total subjects was observed, and there were 17 (9.7%) cases in plating, 4 csaes (14.3%) in dressing and dyeing of leather. In the comparison of chromium concentration in blood and urine between the perforated group and non-perforated group, the perforated group showed a significantly higher value as $1.883{\pm}3.055{\mu}g/dl\;and\;0.793{\pm}0.815{\mu}g/dl$(P<0.001), $21.31{\pm}34.610{\mu}g/L\;and\;9.304{\pm}11.079{\mu}g/L$ (P<0.001). 5. The mean concentration of chromium in blood, urine and the mean level of AST, ALT, Hb and Hct in exposure group were higher than those of control group(p<0.001).

디이젤기관에 있어서 매타놀의 사용

유병철,Yoo, Byung Chul 대한기계학회 1979 대한기계학회논문집 Vol.3 No.1

Methanol was examined as supplemental fuel for open chamber type and pre-combustion chamber type diesel engine. Pre-determined quantities of diesel oil were injected as ordinary diesel engines and methanol was added at inlet pipe using venturi, nozzel and and float chamber for the rest of the charge. In this mode of operation, addition of methanol reduced inlet and exhaust temperature. Inlet air quantities were essentially unchanged in spite of lower inlet temperature. Exhaust smoke was significantly reduced At light load when both diesel oil and methanol were introduced with small quantities, specific heat consumption was considerably increased. However, with the increase of the quantity of methanol or diesel oil, specific heat consumption was improved. With sufficient quantities of diesel oil enough to produce the power above 3/4 load, addition of methanol showed better thermal economy.

전신성 경화증과 동반된 자가면역성 간염에 의한 간경변

유병철 ( Byung Chul You ),정승원 ( Soung Won Jeong ),장재영 ( Jae Young Jang ),구소미 ( So Mi Goo ),김상균 ( Sang Gyune Kim ),김영석 ( Young Seok Kim ),전찬홍 ( Chan Hong Jeon ),진윤미 ( Yoon Mi Jeen ) 대한소화기학회 2012 대한소화기학회지 Vol.59 No.1

Systemic sclerosis (SSc) is a chronic systemic disease that affects the skin, lungs, heart, gastrointestinal tract, kidneys, and musculoskeletal system. Although up to 90% of patients with scleroderma have been estimated to have gastrointestinal involvement, liver disease has been reported only rarely. A 51-year-old woman was hospitalized due to esophageal variceal bleeding. Her serum was positive for anti-nuclear antibody and anti-centromere antibody. Sclerodactyly was noted on both hands, and she had recently developed Raynaud`s syndrome. Punch biopsy of the hand showed hyperkeratosis, regular acanthosis, and increased basal pigmentation in the epidermis, and thick pale collagenous bundles in the dermis. Liver biopsy showed chronic active hepatitis with bridging fibrosis. Consequently, she was diagnosed with liver cirrhosis due to autoimmune hepatitis (AIH) combined with SSc. AIH had subsided after administration of prednisolone at 40 mg per day. She received 5-10 mg/day of prednisolone as an outpatient, and her condition has remained stable. Patients with either AIH or SSc should be monitored for further development of concurrent autoimmune diseases. The early diagnosis of AIH combined with SSc will be helpful in achieving optimal management. (Korean J Gastroenterol 2012;59:48-52).

최근 3년간 급성 바이러스성 간염의 원인 분석

유병철 ( Byung Chul Yoo ),고광철 ( Kwang Cheol Koh ) 대한내과학회 2005 대한내과학회지 Vol.68 No.3

환율변동에 따른 우리나라의 장,단기 비대칭 해외관광수요 분석

유병철 ( Byung Chul Yu ),오지영 ( Ji Young Oh ) 서강대학교 시장경제연구소(구 서강대학교 경제연구소) 2011 시장경제연구 Vol.40 No.2

본 연구는 환율이 장·단기적으로 우리나라 아웃바운드 및 인바운드 관광수요에 어떠한 영향을 미치는가를 분석함에 있어서 장기 및 단기 비대칭성을 고려할 수 있는 비대칭 ARDL모형을 이용하였다. 분석결과, 우리나라 실질실효환율의 내국인 출국수요에 대한 영향력은 공적분 관계를 확인할 수 있었으며, 장기비대칭을 가정한 ARDL모형(장기 비대칭·단기 선형 모형, 장·단기 비대칭 모형)으로 분석 한 결과, 모두 장기 비대칭이 나타났으며, 단기 비대칭에서도 유의한 결과가 나타났다. 장기계수 추정결과환율 상승에 따른 내국인 출국자 수의 감소규모가 하락 시 증가폭 보다 크게 나타나 우리나라 해외 출국자는 환율인상에 더욱 크게 반응하는 것으로 나타났다. 반면 외래객의 입국에 관한 영향력 분석 결과 역시 유의한 공적분 결과가 나타났으며, 장기비대칭을 가정한 ARDL모형에서 장기 비대칭이 있는 것으로 나타났으나, 단기적으로는 유의하지 않은 결과가 나타났다. 또한 환율 상승에 따른 외래객 입국의 증가세가 환율 하락에 따른 감소세 보다 크게 나타나고 있어 외래객 역시 환율 인상에 더욱 민감하게 반응하는 것으로 보인다. The main purpose of this paper is to examine the short-run and long-run asymmetric effect of exchange rate on the inbound and outbound tourists in Korea using the non-linear ARDL Model. We find the cointegrating relations between variable on non-linear ARDL model. This paper finds asymmetries in the response of outbound and inbound tourists to exchange rate changes and long run coefficient is the greater when the won has depreciated than the won has appreciated. The analysis results show that outbound and inbound tourists respond more sensitive to increase in the exchange rate than decrease in the exchange rate.

[論文] 4氣筒 4사이클 스파크 點火機關 吸·排氣 系統의 流動에 關한 硏究

유병철(Byung Chul Yoo),이정현(Jung Hyun Lee) 한국자동차공학회 1988 오토저널 Vol.10 No.1

When gas exchange process is to be calculated, the evaluation of the variation of the thermo­dynamic properties with time and position in the intake and exhaust system is required. For this purpose the application of the method of characteristics to the gas exchange process is known as the best method. In order to apply the method of characteristics, the gas flow at carburettor and inlet and exhaust valves must be replaced by some simple models by which thermodynamic properties can be calculated easily giving good agreement with actual values.<br/> In this study, the carburettor is represented by an adiabatic pressure loss model. In this model resistance coefficients of carburettor are obtained by experiment. Using these resistance coefficients the pressure drop at carburettor can be calculated.<br/> In order to select adequate average discharge coefficients for the inlet and exhaust valves, mass flow rate through intake and exhaust system is calculated by the method of characteristics using above resistance coefficient at specific engine operating condition and then it is compared with measured mass flow rate. The discharge coefficient is determined so that calculated mass flow rate gives good agreement with the measured mass flow rate.<br/> For the engine used in this study average discharge coefficient of 0.6 gives good agreement with the measured mass flow rate over the whole engine operating conditions.

[論文] 單氣筒 2사이클 壓縮點火機關의 시뮬레이션

유병철(Byung Chul Yoo),김정순(Jung Soon Kim) 한국자동차공학회 1986 오토저널 Vol.8 No.1

The simulation of power cycle and unsteady gas exchange processes in the inlet and exhaust systems of the single-cylinder 2-stroke cycle compression ignition engine was studied in this paper.<br/> In power cycle process, the single-zone model proposed by Whitehouse and Way was used, and the convective and radiative heat transfer from cylinder contents to surroundings was considered. To solve the equations for gas exchange process, the generalized method of charac­teristics including area change, friction, heat transfer and entropy gradients was used. Also with the path line calculation, the entropy change along the path line and the variation of specific heat due to the change of temperature and the composition of cylinder gas were considered.<br/> As a result of the simulation, the change of pressure and temperature in the cylinder again­st the crank angle, the rate of net heat release, and the change of properties at each point in the inlet and exhaust pipe against the crank angle were obtained. The engine performances under various operating conditions were also calculated.

실무연구(實務硏究) : 민영교도소(民營矯導所)의 추진상황(推進狀況)과 효율적(效率的) 운영방안(運營方案)

유병철 ( Byung Chul Yoo ) 법조협회 2002 法曹 Vol.51 No.9

[FISITA 參席] 第22回 FISITA大會에 參席하고

유병철(Byung Chul Yoo) 한국자동차공학회 1988 오토저널 Vol.10 No.5