직접 메탄올 연료전지를 위한 anode 전극재료 개발

박경원,이설아,오인환,남석우,하홍용,임태훈,홍성안,성영은 한국공업화학회 1999 응용화학 Vol.3 No.2

Direct methanol fuel cell (DMFC) needs better anode electrocatalysts than Pt, which suffers from self CO poisoning phenomena. The improved oxidation kinetics enabled by Pt promoters such as Ru, Sn, Mo, W or Os has been attributed to a bifunctional and/or an electronic effect. The alloy electrode materials were prepared by reduction and colloidal methods. It was generally proved that binary system such as those based on Pt, these components are much more active in promoting DMFC reactions than pure platinum catalysts. The oxidation onset on pure Pt was 0.45 V and the potentials decreased with alloying. Pt-Ru showed the lowest onset potential. However, chronoamperometry provided high stability at Pt-Mo on CO poisoning, which shows a promising candidate as DMFC anode material. The strategy of ternary or quaternary electrocatalysts, the effects of synthesis and particle sizes will be discussed.

한국형 출혈열 후유증으로 발생된 만성 신우신염

김연수,한진석,이정상,김성권,진호준,안규리,오국환,오윤규 대한내과학회 1997 대한내과학회지 Vol.52 No.4

It has been known that most patients with Korean Hemorrhagic Fever (KHF) were recovered without any significant renal complication. But several cases of renal hypertension, chronic pyelonephritis, and chronic renal failure after KHF have been reported. Recently, we experienced one case of chronic pyelonephritis as a sequela of KHF, which has been diagnosed at the 78th month of illness. This case showed reduced thickness of renal parenchyme, small and irregular shaped kidney, focal loss of normal cupping of calyces, and accumulation of radiacontrast media at distal calyes by IVP. This case suggested that chronic pyelonephritis may develop as a sequela of KHF,

기관지내 전이암

김현수,이상수,오미희,이재갑,원구태,홍희승,용석중,신계철 대한내과학회 1991 대한내과학회지 Vol.40 No.4

The lung is the most common site of metastasis of extrapulmonary malignant tumor. According to past reports, metastatic cancer of the lung has been found in about 2% of all patients at autopsy. But these days, a diagnosis of endobronchial metastatic cancer utilizing bronchoscopy only is not easy. Thus we need other means of gathering more informaction, such as past history, discovery of other metastatic sites, and pathologic findings with special staining and electronmicroscope, especially in cases of poorly differentiated adenocarcinoma and epidermoid cancer, which are common types of primary lung cancer. We present 5 cases of endobronchial metastatic cancer. We found endobronchial metastatic cancer 2 cases of cervix cancer (epidermoid, adenocarcinoma), 1 case of colon cancer (adenocarcinoma), hypernephroma (renal cell carcinoma), and bladder cancer (transitional cell carcinoma). Since it was impossiole to diagnose the metastatic adenocarcinoma from the cervix only with lightmicroscopic findings, we could use past history and unusual radiologic and bronchoscopic findings which was thought to be the specific endoscopic finding of metastic endobronchial cancer. The interval between the diagnosis of the primary cancer and endobronchial metastatic cancer was 25.7 months. In the future, development of immunohistochemistry, monoclonal antibody, and molecular biologic techniques will give us diagnostic clue for differential diagnosis of metastatic endobronchial cancer from primary bronchogenic lung cancer.

실리콘 직접 접합/전기화학적 식각정지를 이용한 실리콘 다이아프램의 형성과 실리콘 압력센서 제조에의 응용

김성환,주병권,김철주,차균현,오명환,하병주,김근섭,송만호 한국센서학회 1994 센서학회지 Vol.3 No.3

A new type of Si diaphragm was fabricated using Si-wafer direct bonding and two-step electrochemical etch-stopping methods. Using the new diaphragm structure in mechanical sensors, more precise control of cavity depth and diaphragm thickness was achievable. Also, the propagation of the stress, which was generated near the bonding interface, to the surface can be avoided. Finally, a piezoresistive-type Si pressure sensor was fabricated utilizing the diaphragm and a digital pressure gauge, which can display units of pressure, was realized.

중탄소 Boron 강의 가스침질탄화처리에 의해 형성된 화합물층의 마모특성에 관한 연구

이상윤,이해우,조효석,이준범,박기원,오도원 한국열처리공학회 1999 熱處理工學會誌 Vol.12 No.2

The study on the wear characteristics of compound layers formed during gaseous nitrocarburising in the medium carbon boron steels and the plain carbon steel has been carried out by using a pin-on-disc type wear test machine under the oil lubricating condition at room temperature and by varying applied loads, sliding speeds and wear distances. Values of friction coefficient measured at the sliding speed of 0.4m/sec under the oil lubricating condition have been shown to decrease considerably with increasing applied load and become gradually a constant value as load is increased to a higher value, showing that the transition load for friction coefficient appears at an applied load of 247.2N. The length and volume wear rates of compound layer have been revealed to relatively constantly increase, also showing that the wear life per unit thickness of compound layer turns out to be superior as porous layer has a denser and thinner appearance. As the sliding speed increases during wear test performed by varying sliding speed at a load of 63.2N under the oil lubricating condition for medium carbon boron steel nitrocarburised in gas atmosphere, the wear rate has been found to increase, the friction coefficient to decrease and the wear life per unit thickness of compound layer to decrease considerably.

일부 영세 도금사업장의 국소배기성능과 공기중 총크롬 , 6가 크롬 및 니켈농도와의 관계분석

박동욱,박두용,신용철,오세민,정규철 한국산업위생학회 1993 한국산업보건학회지 Vol.3 No.1

To evaluate efficiencies of the local exhaust systems installed in chromium and nickel electroplating tanks, specifications of each tank and general performances of the local exhaust systems were measured in 16 electroplating plants from July 3 to November 24, 1992. Airborne concentrations of total chromium, hexa-chromium and nickel were also measured. Most of the local exhaust systems installed in electroplating plants were inadequately designed. Average capture velocities of local exhaust systems in chromium and nickel tanks were 0.45 m/sec and 0.29 m/sec. Average slot velocities in chromium and nickel tanks were 7.30 m/sec and 2.87 m/sec respectively. Both average capture and slot velocities were in noncompliance with the standards recommended by American Conference of Governmental Industrial Hygienists (ACGIH) and National Institute for Occupational Safety and Health (NIOSH). Exhausted air volume was insufficient in all local exhaust systems surveyed. Worker exposure levels to total chromium, hexa-chromium and nickel were 43.0 ㎍/㎥, 1.7 ㎍/㎥ and 9.3 ㎍/㎥, which were below the Korean Standard and U.S. Occupational Health and Safety Administration (OHSA) Permissible Exposure Limit (PEL). However, Worker exposure level to hexa-chromium exceeded the NIOSH Recommended Exposure Limit(REL) of 1 ㎍/㎥. As the result of Scheffee's multiple comparions, worker exposure levels to all metals were significantly different between two groups by the management state of existing local exhaust systems (p$lt;0.05). However, Difference between a group with local exhaust systems which were poorly managed and another group without local exhaust system was satatistically non-significant.

매설 천연가스배관의 지반침하에 의한 응력 분석

홍성호,김우식,김형식,방인완,오규환 한국산업안전학회 1998 한국안전학회지 Vol.13 No.2

This study was initiated to examine the stress and deformation characteristics of the pipelines which were subjected to various environmental conditions in order to confirm their integrity. As the part of them, this paper presents the analysis results for the effect of ground subsidence combined with main loads on buried natural gas pipelines. The ground subsidence which can occur for buried gas pipeline has been classified to the three cases. Finite element method was used to analyze the effect of ground subsidences on pipeline of 26 inch(0.660 m) and 30 inch(0.762 m) diameter used as high pressure (70㎏_f/㎠(6.86 ㎫)) main pipelines of KOGAS. This paper shows the result of stress analysis for the pipelines subjected to those three case ground subsidence. Comparing these results with safety criterion of KOGAS(0.9 σ_y), maximum allowable settlement and loads have been calculated.

리튬 2 차 전지의 양극재료인 스피넬 망간산화물의 용해와 용량감소

오승모,이종화,홍진규,장동훈 한국공업화학회 2001 공업화학 Vol.12 No.2

복사전열 가열로 튜브의 파손방지에 대한 연구

윤기봉,심상훈,유홍선,오현환 한국산업안전학회 1998 한국안전학회지 Vol.13 No.1

Radiant heater tubes with an inside burner are designed to transfer the heat generated from the burner to the outside of the tube by radiation. Hence, tube metal must suffer high temperature of approximately 900-1000℃. The radiant tube is usually manufactured by centrifugal casting with high Ni-Cr alloys. In this study, failure analysis results of the radiant tube arc reported. Failure mechanism of the tube was investigated by visual observation of the failed tube, metallographic study of the cracked region and chemical analysis of tube metal and oxide scales. It was argued that the main cause of the cracking is repeated oxidation of the tube metal located beneath the thick oxide scale. Oxidation was caused by abnormally high operating temperature which can be verified by aged microstructure and internal void formation.

Dodeyl diamino thyi glycin hydrochloride(Hygien 51)의 각종항산균에 대한 항균작용에 관한 시험관내 실험

황청자,진재신,김주덕,오흥근 대한마취과학회 1970 Korean Journal of Anesthesiology Vol.3 No.1

In order to prevent cross-infection, the sterilization of used and/or contaminated anesthetic- apparatus is still a difficult problem in clinical practice, particularly, following anesthesia for known advanced pulmonary tuberculosis cases. Therefore the antibacterisl activities of, an amphoteric detergent, Dodecyl diaminoethyl glycin hydrochloride (Hygien 51) were tested in vitro as a disinfectant against mycobacteria (M. tuberculosis H37 Rv, M. bovis, M. avium, M. tuberculosis H37 Ra, M. phlei, B.C.G.) The antimycobacterial activity tests were perfomed according to the modified Kolmer method. The testing organisms were cultured in Dubos broth at 37°C, and the detergent, Hygien 51, was: diluted with sterile distilled water to 1,3,5 and 10%. One half milliliter of culture was pipetted into each tube containing 4.5 ml of diluted detergent, and at intervals of 3, 15, 30, 60, 120, 180 and 240 minutes, a 4mm loopful of the material was removed from each tube, and transferred to Ogawa media. The tests were carrid out at two different temperatures, 20°C and 50°C. The subcultures were incubated at 37°C for more than 8 weeks. The results were obtained as follows: 1) At room temperature (20°C), all mycobateria, except M. bovis, were destroyed by treatment- with 10% solution of the detergent for more than 60 minutes. M. bovis was relatively sensitive to the detergent, and was killed by 5% solution for 30 min. and 10% for 15 min., but M. avium. was very resistant, and was not killed by 10% solution for 240 min. 2) By treatment with the detergent at 50°C, the antimycobacterial activities of the detergent were highly increased. All mycobacteria were destroyed by 1% solution for 180 min, and by 10% for less than 30 min at 50°C. In the comparison of the antibacterial activities against mycobacteria and other bacteria, it shows that mycobacteria are generally more resistant to the detergent, Hygien 51.