방전 플라스마에 의한 CFC-12(CCl2F2)의 분해

황명환,우인성,조정국,강현춘,안형환,이한섭,강안수 한국산업안전학회 1999 한국안전학회지 Vol.14 No.3

Decomposition efficiency, power consumption, and applied voltage of CFC(Chlorofluorocarbon) were investigated by SPCY(surface induced discharge plasma chemical processing) reactor to obtain optimum process variables and maximum decomposition efficiencies. Decomposition efficiency of CFC-12 with various electric frequencies(5∼50㎑). flow rates (100∼1,000mL/min), initial concentrations(100∼1,000ppm), electrode materials(W, Cu. Al), electrode thickness(1, 2, 3mm) and reference gases(N₂, O₂, air) were measured and the products were analyzed with FT-IR. Experimental results showed that at the frequency of 10kHz, the highest decomposition efficiency of 92.7% for CFC-12 were observed at the power consumptions of 29.6W, respectively, and that decomposition efficiency decreased with increasing frequency above 20㎑ and decomposition efficiency per unit power were 3.13%/W for CFC-12. Decomposition efficiency was increased with increasing residence times and with decreasing initial concentration of pollutants. Decomposition efficiency was increased with increasing thickness of discharge electrode and the highest decomposition efficiency was obtained for the electrode diameter of 3mm. As the electrode material, decomposition efficiency was in order that tungsten(W), copper(Cu), aluminum (Al).

프로골프선수의 슬관절 등속성 근력에 관한 굴곡근과 신전근의 비교연구

박성태,정성태,정덕조,정영수,엄우섭,전태원,우재홍,박익렬 한국운동과학회 2000 운동과학 Vol.9 No.1

프로골프선수의 슬관절 등속성 근력에 관한 굴곡근과 신전근의 비교연구. 운동과학, 제 9권 제 1호. (201)-(209), 2000. 본 연구는 장기간의 골프운동이 슬관절의 단축성 굴근력과 신근력의 발달에 미치는 영향을 규명하여 경기력 향상을 위한 트레이닝 방법의 기초자료를 제공하고자 수행 되었다. 연구의 대상은 24명의 프로골프선수들(29.60±3.8세)로 골프경력은 12±1.7년으로 대상자 전원이 오른손을 주로 사용(우타)하였다. 측정은 등속성근력계(Cybex 770)를 이용하여 각속도 60°/sec와 180°/sec에서 3회씩 좌·우 교대로 측정하였다. 측정변인은 peak torque, peak torque 발현각, 평균파워, 총운동량 등이었다. 자료분석은 SPSS통계프로그램을 이용하여 실시하였으며 다음과 같은 결론을 얻었다.; 슬관절 굴곡근과 신장근의 좌·우 근력 비교에서 각속도 180°/sec로 굴곡성 운동시 총 운동량(total work)에서 좌·우측간에 유의한 차이가 있는 것으로 나타났으나(p<.05), 나머지 측정변인에서는 굴곡근과 신전근 모두 부하각속도에서 통계적으로 유의하지 않았다. 굴곡력의 경우 우측하지가 좌측하지에 비하여 높았으나 신전력의 경우 좌측하지가 다소 높은 경향을 보였다. 각 변인의 평균치에 대한 60°/sec와 180°/sec간의 비교에서는 모든 변인에서 통계적으로 유의한 차이를 나타내었다(p<.05). 슬관절 굴곡근의 신전근에 대한 비율(Flexor/Extensor Ratio)은 60°/sec에서 60%보다 낮게 나타났으나 좌·우측간 유의하지는 않았다. 결론적으로 다년간의 골프운동은 하지의 슬관절 근기능을 발달시키며 우측하지에 비해 좌측하지의 신전근에 더 많은 발달을 가져온다고 할 수 있다. A study on isokinetic concentric torque of kee extensor and flexor in golf players. Exercise Science, 9(1): 201-209, 2000. The purpose of this stydy was to investigate the effect of long therm golf exercise on isokinetic concentric torque of kee extensor and flexor. The subjects of this study were 24 men progolf players(29.60±3.8yrs) who have experience of 12±1.7yrs golf exercise and use mainly a right hand. The measurement was performed by use of Cybex 770 in angular velocity 60˚ /sec, 180˚ /sec and 3 repetitions. The variable of measure were peak torque, angle of peak torque, average power, total work and so on. The result of this study were as follow: There only was statistical difference between both low limb in Total work of knee flexor in angular velocity 180°/sec(p<.05) but not in other variables in both angular valocity. Right low limb was little stronger than reft low limb in flexor but there was opposite result in extensors. There was statistical difference between 60°/sec and 180°/sec in all varible. Knee flexors and extensors ratio was lower than 60% in angular velocity 60°/sec but there was no statistical difference between right and left low limb. It might be concluded from the test that long term golf exercise strengthen muscle function of knee flexors and extensor and left knee extensors more strengthen than right knee extensors.

중증근무력증 환자 마취 8 예 경험

김용철,길찬일,신정순,장진경,임혜자,우설희 대한마취과학회 1983 Korean Journal of Anesthesiology Vol.16 No.3

Myasthenia Gravis is a chronic disease of disputed etiology, possibly an auto-immune reaction to the moter end-plate, characterized by exacerbations and remissions, a rare disease entity in Korea. Myasthenia Gravis has offered many anesthetic problems because it affects respiratory muscles occasionally and bronchial secretion from preoperative anticholinesterase therapy. The chief concern is to ensure adequate respiration both during and after operation. During the year 1976-1982, we have experienced the anesthetic management of 8 patients with myasthenia gravis and thymectomy. From our experiences, we conclude that respiratory care and disuse of relaxants is the key to successful management.

진동형 분진 최소착화에너지측정장치에서 분진 응집현상이 미치는 영향

정재희,최충석,목연수,최광석,황명환,우인성,Yamaguma, M.,Kodama, T.,Cheung, W.L. 한국산업안전학회 1999 한국안전학회지 Vol.14 No.3

It is widely recognized that Hartmann tube for measuring the minimum ignition energy(MIE) of powder. But It requires long time and operational skills for measuring. As a variety of new fine powders are being produced day by day in industry, Japen has been developing a measurement system which employs a new method to create a dust/air mixture in a miniature combustion box. In this system, by vibration, the powder is successively fed downward through a hopper made up of metal mesh, and then it is formed into a thin, certain-like, dust/air mixture. With this new apparatus, three types of powder-Lycopodium, Anthraquinone, and Polyacrylonitrile-were tested and the data of MIE were compared with those of a conventional apparatus (the Hartmann tube). Two of them agreed satisfactory, but the other, Anthraquinone, showed quite different values. It is guessed that the agglomerations of the powder particles appear because of particle shapes, static-charge and humidity.

B 첨가 고탄소강의 흑연화에 미치는 냉간압연의 영향

박영구,우기도,이창희,류재화,나종필 한국열처리공학회 1999 熱處理工學會誌 Vol.12 No.2

The graphitization is affected by the addition of small amount of the elements(such as Si, Al, Ni, B, Cr and Mn etc.) and the pre-treatment(such as cold rolling). Boron is well known element to accelerate the graphitization of cementite in high carbon steels. Also, cold rolling is known to accelerate the graphitization. But the graphitization nucleation mechanism by cold rolling is few reported. Therefore the effect of cold rolling in Fe-0.5%C-1.0%Si-0.47%Mn-0.005%B steel on the graphitization is investigated quantitatively using hardness test, optical microscope and scanning electron microscope, neutron induced microscopic radiography. The nucleation of graphite in cold-rolled Fe-0.5%C-1.0%Si-0.47%Mn-0.005%B steel is formed at void which is formed at pearlite/pearlite boundary by cold rolling. But the effect of cold rolling on graphitization in boron addition steel is more effective than that of no boron addition steel due to segregation of BN at void in boron addition steel.

리튬이차전지용 Li1.05CoO2 음극재료의 전기화학적 특성 연구

김정식,우선기,류호진,이학로,김인석 대한금속재료학회(대한금속학회) 1999 대한금속·재료학회지 Vol.37 No.7

A Li_(1.05)CoO₂ powder has been prepared by the solid state reaction of Li₂CO₃ and Co₃O₄ at 1000℃. Li_(1.05)CoO₂ powder was characterized a layered structure with space group of R3￣m by XRD analysis. But Li_(1.05)CoO₂ has a shorter c-axis than LiCoO₂ because, in the former case, a coulombic interaction is more dominent than elastic strain energy effect. In this experiment, electrochemical properties about porous Li_(1.05)CoO₂ were investigated by galvanostatic, CV(Cyclic Voltammetry) and GITT(Galvanostatic Intermittent Transient Technique) method.

중첩방전 반응기에 의한 오존의 생성

이영희,YAMAGUMA,M .,목연수,황명환,우인성,조정국 한국산업안전학회 1999 한국안전학회지 Vol.14 No.3

In this paper, characteristics of ozone generation by using coil and SPCP+DC corona reactor was studied. The ceramic-based surface discharge electrode, which was first invented as a high-efficiency ozonizer, has been used as an experimental plasma chemical reactor.(Surface Induced Plasma Chemical Processing, SPCP.) The electrode, however, has a structural disadvantage that a highly energetic plasma region is localized near the electrode surface, which may make it impossible for higher efficiency to realize. In an attempt to overcome this advantage, we have developed a hybrid reactor which employs a corona discharge unit together with the surface discharge unit. Experimental results suggest that the efficiency of the ozone production rate is improved when positive corona discharge is added.

원호형 문비(Tainter Gate) 의 동적 거동 해석

이성행,정경섭,우상익,전제상 충북대학교 건설기술연구소 1996 建設技術論文集 Vol.15 No.1

A fluid analysis and transient dynamic analysis were performed for tainter gate to find out a proper bottom geometries of gate and to investigate the dynamic behaviors. Firstly, natural frequencies were analyzed to examine the dynamic characteristics of fainter gate, then natural frequencies and mode shapes were displayed in each mode. Secondly, the distribution of pressure and velocity were analyzed, and these results were loaded at the boundary of fainter gate to implement the transient dynamic analysis of the flow at the boundary of bottom geometries of gate with $quot;A$quot; and $quot;B$quot; type models which were tested at previous study. In this paper, the dynamic behaviors of fainter gate were discussed, and the bottom geometries of gate to reduce the amplitudes of vibration were proposed.

고온자전합성법에 의한 Ti/Al 복합판재의 미세조직 형성과정

박우진,안상호,정재영,김낙준,이원철 대한금속재료학회(대한금속학회) 1998 대한금속·재료학회지 Vol.36 No.10

Microstructural evolution of Ti/Al layered structures annealed at various temperature has been investigated by using optical microscopy, scanning electron microscopy, and X-ray diffractometry. Ti/Al layered sheets have been produced by dipping two Ti sheets in Al melt. The Ti/Al interfaces showed good bonding characteristics in as-dipped sheet. Microstructure of the heat-treated Ti/Al sheet varies depending on the subsequent annealing temperature. In the Ti/Al layered composite annealed at temperature below Al melting point, thin TiAl₃ layer was formed by the diffusion process at the Ti/Al interfaces. In the case of composite exposed at temperature above Al melting point, the equiaxed TiAl₃particles protruded into Al matrix from the thin TiAl₃ layer as well as the formation of thin TiAl₃ layer. TiAl₃ particles become homogeneously distributed within the Al matrix away from the Ti/Al interface with increasing annealing time. The formation of TiAl₃ phase in Ti/Al sheet annealed at temperature above Al melting point is believed to be formed by the exothermic chemical reaction.

역사이클하중하에서의 균열길이 측정법에 따른 파괴저항곡선의 평가

원종일,우흥식,석창성 한국산업안전학회 1998 한국안전학회지 Vol.13 No.4

J-R curve tests were performed on 1T compact specimens of SA516 Gr. 70 carbon steels under reverse cyclic loading. A Direct-Current Potential Drop (DCPD) method, one of the nondestructive techniques to detect flaw of structure, is being increasingly used for monitoring crack initiation and stable crack growth in typical fracture mechanics specimens for J-R testing. In many aspects this method is simpler than the unloading compliance method. The objective of this paper is to evaluate the J-R Curve according to the crack length measurement techniques under reverse cyclic loading. In order to prove the reliability and repeatability of the DCPD method, the crack length measured by using DCPD method was compared to one determined from unloading compliance. Consequently, this DCPD method correlated well with J-R curves and crack extension measurements determined from unloading compliance method.