국민건강보험 청구자료원을 이용한 임상연구의 입문

류동열 이화여자대학교 의과학연구소 2017 EMJ (Ewha medical journal) Vol.40 No.2

대한 외국인 직접투자의 소유지분 유형과 변화추이에 관한 탐색적 연구

뱍영렬,김택권,김동재 연세대학교 경영연구소 1998 연세경영연구 Vol.35 No.2

본 연구에서는 1962년부터 1993년 3월 말까지의 한국내 외국인 직접투자에 있어 소유지분의 변화를 중심으로 이들 국가 및 그룹 간의 차이를 비교·분석하였다. 본 연구결과에 의하면 통제수단으로서의 소유지분의 역할이 국가에 따라 다르게 나타났다. 미국기업의 경우 소유지분이 중요한 통제수단으로 나타나고 있으나, 일본기업의 경우는 그렇지 못하다. 그리고 일본기업의 경우 기존 연구와는 달리 합작투자의 규모가 작음에도 불구하고 소수지분을 선호하는 것으로 나타났다. 또한, 프로젝트의 규모가 클수록 소수지분을 선호한다는 기존의 연구와는 달리 일본기업들의 경우에는 프로젝트의 규모가 작은데도 불구하고 여전히 소수지분을 선호하는 현상을 보이고 있다.

휘발성유기화합물로 오염된 토양의 계면활성제 세척시 처리효율 비교 -환경부의 환경주제도 및 승인통계를 중심으로-

오동익,최청렬 대구대학교 환경기술연구소 2005 미래환경기술 Vol.1 No.2

지반 내에서의 휘발성 유기 화합물의 수착 거동을 이해하고 계면활성제를 이용한 추출효율을 측정하여 적용가능성을 검토하기 위하여 수착 실험과 연속 탈착 실험을 실시하였다. 김포 수도권 매립지 3공구 원지반 흙을 대상으로 하였고, 휘발성 유기 화합물로는 benzene, ethylbenzene, toluene, o-xylene, p-xylene등과 같은 BTEX류와 TCE를 사용하였다. 계면활성제로는 Brij 35, Triton X-100, Tween 20 등의 비이온성 계면활성제와 DowFax(음이온성 계면활성제)를 사용하였다. 실험에 선정된 대상 유기 화합물의 김포매립지 원지반 흙으로의 수착은 4일 이내 평형에 도달하였다. 대상 유기 화합물로 오염된 흙을 계면활성제 용액을 주입하여 세척한 결과, 물만으로 세척했을 때보다 좋은 세척효율을 보였다. 실험에 선정된 계면활성제들은 CMC값의 2배로 주입된 경우가 1배, 4배의 경우로 주입된 경우에 비하여 세척효율이 가장 우수하였다. Twin-head group을 가진 음이온성 계면활성제인 DowFax가 비이온성 계면활성제(Triton X-100, Tween 20, Brij 35)에 비해 대상 휘발성 유기 화합물에 대한 세척효율이 우수하였다. Sorption isotherm tests and successive reverse isotherm tests using Kimpo Sudokwon landfill soil were conducted (1) to understand the sorption behavior of volatile organic compounds onto a soil; (2) to investigate the extraction efficiencies of surfactants; and (3) to evaluate the field application of surfactant extraction technology. Benzene, ethylbenzene, toluene, trichloroethylene, o-xylene, and p-xylene were selected as the target compounds. Three nonionic surfactants, i.e., Brij 30, Triton X-100, and Tween 20 and a anionic, DowFax were used for tests. The sorption of the VOCs tested in this study onto the soil reached equilibrium in 72 hours. The VOC extraction efficiencies of surfactants from the VOC contaminated soil specimens were higher than those of distilled water. When the dosage of surfactant were two times of CMC, the VOC extraction efficiency were the greatest among the dosages tested. DowFax which contains two-head group showed much higher VOC extraction efficiency than the other tested nonionic surfactants.

수종 수산화칼슘 Sealer의 근관폐쇄효과에 관한 전기화학적연구

신동훈,최국렬,홍찬의 大韓齒科保存學會 1995 Restorative Dentistry & Endodontics Vol.20 No.1

AbstractThe purpose of this electrochemical study was to determine and compare the sealing effect of three commonly used calcium hydroxide-based sealers (Sealapex, Apexit, and CRCS) with that of Roth 801 which is a ZOE-based sealer.64 single rooted teeth were used in this experiment. After removing the crown, the teeth were devided into 4 groups of 15 in each and obturated with gutta-percha and experi- mental sealers. 4 teeth were as controls(2 positive and 2 negative).The results were as follows : 1. During the observation period, all sealers showed varying degree of microleakage. 2. The mean leakage currents according to the electrochemical study of each group showed 0.418??0.006mV for Roth 801, 2.03??0.035mV for Sealapex, 3.33??0.069mV for Apxit and 6.48??0.097mV for CRCS group. The positive control group showed 600mV. 3. There were statistically significant difference in mean leakage among experimental groups. ZOE-typed Roth 801 sealer was the lowest, and Sealapex, Apexit, CRCS group in that order showed increased leakage (P<0.05). 4. Roth 801, Sealapex and Apexit group showed increasing leakage with time, but CRCS group showed stable or decreasing leakage tendency.

PECVD로 제작한 수소화된 비정질 탄소(a-C:H) 박막의 광학적에너지 갭과 전기전도도

박혁렬,이석호,오동선,홍선화 木浦大學校基礎科學硏究所 1996 基礎科學硏究誌 Vol.14 No.-

Hydrogenated amorphous carbon(a-C:H) films were deposited onto glass or Si-wafer substrate from CH₄ gas by using PECVD(plasma Enhanced Chemical Vapor Deposition) method. The films were deposited at various substrate temperatures and two different position of the substrate. The optical and electrical properties of the deposited films were characterized by measuring such as UV/VIS transmission spectrum, FTIR absorption spectrum and dark electrical conductivity. We found a decreased in deposition rate and optical energy gap as the substrate temperature was increased. The deposition rate was increased for the films deposited at IS(ion-sheath) region than at BP(bulk-plasma) region, while the optical energy gap was increased for the films deposited at BP than at IS region. We obtained a very hard diamond-like-carbon(DLC) films at IS region and in optimal substrate temperature. The films showed a thermally activated conduction with an activation energy of about 0.24 eV above 400 K, while a variable range hopping conduction below about 400 K.

KC80196을 이용한 Profibus Interface Card 구현

송동섭,신동렬 成均館大學校 科學技術硏究所 1999 論文集 Vol.50 No.1

Due to the advances in data communication and hardware technology, many centralized control systems have been replaced by distributed digital systems. Fieldbuses are low level industrial networks and are currently undergoing enormous revolution. Industries have recently observed lots of applications using fieldbus networks. Profibus is one of fieldbus currently available. In this paper we describe the interface between the applications and the Profibus network and then implement an interface card on DIN 19 245 Profibus Standard. We show that this implementation is a useful technique of converting serial communication to intelligent polling network as well as the efficient and simple design.

타타늄의 열처리 조건에 따른 동전위 양극분극특성 및 표면 미세구조 변화

주동현,이용렬,정영화,양홍서,박상원,이도재,송호준,박영준 大韓齒科器材學會 2002 대한치과재료학회지 Vol.29 No.2

The corrosion resistance of metallic implants is essential for successful implant osseointegration. Moreover, the implant surface should have appropriate surface roughness for the attachment of the osteoblast and collagen fibrils. When titanium is exposed to air a thermodynamically very stable oxide film is formed at once. This oxide is very thin and yet it protects the metal from corrosion instantaneously. However, the oxide would not be ideal, and it would be supposed that the state of oxide film would be various by the different conditions when it is formed. The objective of this study was to evaluate the electrochemical properties and surface microstructural changes of titanium after passivation treatment or exposure to high heat (in vacuum or in air). ASTM grade 2 commercially pure titanium (Ti) disks of 10㎜ diameter were wet ground and polished with 240 and 600 grit SiC, and then ultrasonically cleaned with distilled water and ethanol. Cleansed as-received samples (As-R group) were passivated with 30% nitric acid solution at 50℃ for 15 minutes to make the Pas group. The Std-V samples were made by treating the Ti disks in vacuum quartz tube (10^-8 Torr) at 530℃ for 40 min for stress relieving, followed by annealing at 700℃ for 90 min, and then slow cooling to room temperature. The Std-A samples undergo identical procedure as the Std-V group except that it is done in air. For 530℃-V samples, Ti disks were heated at 530℃ for 40 minutes and slow cooled to room temperature. The 1000℃-V samples were produced by heating Std-V specimens again at 1000℃ for 2 hr, followed by cooling to room temperature. 530℃-A and 1000℃-A samples were also prepared. Potentiodynamic anodic polarization measurement, SEM, AFM and XRD analysis were performed to evaluate the effects of the various treatments. The difference in the mean values of E_corr between groups showed statistically significant difference (P<0.05), but that of I_corr did not show significance (P>0.05). When Ti surface was passivated there was a shift of corrosion potential (E_corr) in the noble direction and a lower corrosion current density (I_corr) value. Std-A samples showed most noble E_corr value among the tested groups. 530℃-V samples showed more noble E-corr than other tested groups except Std-A group. 1000℃-V samples showed more noble E-corr than those of Std-V sample. In the case of Std-, 530℃- and 1000℃-groups, -A sub-groups showed better corrosion resistant characteristics than -V sub-groups in regard to E-corr and I_corr values. In the SEM observations, the surfaces of the As-R samples showed only scratch line on smooth surface. In Pas samples, thick oxide layer covered the surface under high magnification observation. 530℃-A samples were covered by oxide granules, and Std-A samples had 25~50 nm-thick acicular oxides. The 1000℃-A samples were covered by coarse oxide crystals with a granule diameter of 0.1~0.6 μm having a gross appearance of milky white color, which was identified by XRD as a rutile. On the other hand, 1000℃-V samples showed an Widmansta¨tten structrue of which the orientation of the lattice is formed along crystallographic planes of the parent crystals. On the AFM observation, 530℃-A samples showed RMS roughness of 79.38 nm which is 5 times rougher than those of the As-R samples. Std-A sample had a roughness of 330.47 nm which is about 20-times rougher than that of the As-R sample. 1000℃-A samples were covered by coarse granular oxides and the roughness were about 0.56 μm. Vacuum sub-group samples showed a more smooth surface than air sub-group samples, and the oxide film was more dense. Due to variability of the surface treatment and heat treatment conditions, the process of the oxide formation seems to be affected thereby making the corrosion properties and surface micro-morphology different. However, more various electrochemical analysis together with surface analysis, and an investigation for the effects of those on the osteoblast cell adhesion and calcium phosphate apposition are needed for the improvement of the osseointegration rates of the titanium implants.

인공방광대치술을 받은 환자에서의 대사 산증 발생

김새인,이동현,김광현,류동열,김승정,강덕희,최규복,이신아 이화여자대학교 의과학연구소 2015 EMJ (Ewha medical journal) Vol.38 No.3

Objectives: Metabolic acidosis frequently develops in patients after neobladder reconstruction. However, the incidence of metabolic acidosis in patients with neobladder and the factors associated with the development of metabolic acidosis have not been well elucidated. We aimed to investigate the incidence and the potential predictors for the development of metabolic acidosis after neobladder reconstruction with intestinal segment. Methods: We included patients who underwent neobladder reconstruction using intestinal segment at Ewha Womans University Mokdong Hospital between January 1, 2005 and December 31, 2014. A subgroup of patients according to the time of metabolic acidosis occurrence was further analyzed in order to characterize predictors for metabolic acidosis. Results: Metabolic acidosis was encountered in 79.4% of patients with neobladder during follow up period. When patients were divided into 2 groups according to anion gap (AG), total CO2 (18.9±2.1 mEq/L vs. 20.0±1.3 mEq/L, P=0.001) and chloride (106.6±4.9 mE/L vs. 109.4±3.6 mEq/L, P<0.001) were significant different between groups with AG>12 and AG≤12. Furthermore, when patients were divided into 3 groups; patients with metabolic acidosis at postoperative day (POD) 1; from POD 2 to 14 days; after 14 days, there was significant difference among those subgroups. Conclusion: Our study showed the rate of metabolic acidosis in patients underwent neobladder reconstruction and the difference between patients with metabolic acidosis and those without metabolic acidosis for the first time in Korea. In the future, well designed prospective study will be needed to prevent metabolic acidosis after neobladder reconstruction.

소형보행로봇의 이동방법에 관한 연구

박재준, 김동주, 최혁렬 성균관대학교 기계기술연구소 2001 성균관대학교 논문집 기계기술편 Vol.4 No.1

This paper describes the locomotion method of Walking robots by introducing two robots, a biped walking robot and a quadraped walking robot, whnch we have manufactured. The biped robot made of LEGO MINDSTORM has bean destined to have the minimal number of actuator. It presents a locomotion method in which robots can walk with a few actuators. The Quadraped Walking robot has three dgree of freedom per a leg, and use RC Servo motor as actuator. we researched walking pattern of quadrated walking robot through this robot. In this paper we also discuss the problems of developing walking robots and solutions.

정보통신 서비스 산업에서의 신규투자 및 인수결정요인

박영렬,김동재,이정훈 연세대학교 경영연구소 2001 연세경영연구 Vol.38 No.1

본 연구는 세계 정보통신 서비스 기업의 해외시장 진입에 있어서 신규투자와 인수의 선택에 영향을 미치는 결정요인을 거래비용이론과 인수합병이론을 이용하여 실증적으로 분석하였다. 본 연구결과에 의하면 무선통신 사업분야에 진출할 경우, 그리고 잠재성장률이 높은 시장에 진출할 경우 정보통신 기업은 인수를 선호하는 것으로 나타났다. 그러나 정보통신 기업의 규모, 기술적 지식, 해외 사업경험 및 진입시장의 과거성장률은 신규투자와 인수 결정에 영향을 미치지 않는 것으로 분석되었다.