• Journal of Electrochemical Science and Technology
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• 제11권4호
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• pp.430-436
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• 2020

Lithium thionyl chloride (Li/SOCl₂) batteries exhibit the highest energy densities seen in commercially available primary batteries because of their high operating voltages and discharge capacities. They are widely used in various extreme environments; however, they show signs of degradation at high discharge currents. The discharge performance of Li/SOCl₂ is considered to be greatly dependent on the carbon materials used in the cathode. Therefore, suitable carbon materials must be chosen to improve discharge performances. In this work, we investigated the discharge properties of Li/SOCl₂ batteries in which the cathodes contained various ratios of acetylene black (AB) and multi-walled carbon nanotubes (MWCNTs) at high discharge currents. It was confirmed that the MWCNTs were effectively dispersed in the mixed AB/MWCNT cathodes. Moreover, the discharge capacity and operating voltage improved at high discharge currents in these mixed cathodes when compared with pure AB cathodes. It was found that the mesopores present in the cathodes have a strong impact on the discharge capacity, while the macropores present on the cathode surface influence the discharge properties at high discharge rates in Li/SOCl₂ batteries. These results indicate that the ratio of mesopores and macropores in the cathode is key to improving the discharge performance of Li/SOCl₂ batteries, as is the dispersion of the MWCNTs.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2003년도 추계학술발표회
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• pp.426-430
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• 2003

Subsurface biobarrier technology has potential applications to contain contaminated groundwater and/or to degrade toxic pollutants in groundwater. Effective biobarrier formation is need to assess of hydrogeologic characteristics and to conduct practical operation strategies and design based on this prior to design biobarrier. Thus, in this study, we examined hydrogeologic characteristics in biobarrier construction site. Hydraulic conductivities which calculated from slug test data have shown difference with each well as 1.20$\times$10$^{-3}$ -6.00$\times$10$^{-5}$ cm/sec. Tracer test is a method in which concentration of tracer solution during withdrawal in each well by vacuum extraction system is measured with time. Tracer solution was continuously injected by constant head tank. Measured tracer concentration versus time data were fitted to analytical solution of convection dispersion equation (CDE). The fitting data of CDE to the measured data at each extraction well yielded were 0.61cm/min(pore velocity), 5.38$\textrm{cm}^2$/min(dispersion coefficient) for discharge rate of 0.47 1/min and 1.75cm/min(pore velocity), 36.34$\textrm{cm}^2$/min(dispersion coefficient) for discharge rate of 0.93 1/min. As a result, we acquired fundamental parameters which need to design biobarrier and operation strategies.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2007년도 추계학술대회 논문집
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• pp.203-204
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• 2007

This paper investigated the influence on partial discharge distribution of various defects at the model power cable joints interface using K-means clustering. As the result of analyzing discharge number distribution of ${\Phi}-n$ cluster, clusters shifted to $0^{\circ}\;and\;180^{\circ}$ with increasing applying voltage. It was confirmed that discharge quantity and euclidean distance between centroids were increased with applying voltage from the analyzing centroid distribution of ${\Phi}-q$ cluster. The degree of dispersion was increased with calculating standard deviation of ${\Phi}-q$ cluster centroid. The tendency both number of discharge and mean value of ${\Phi}-q$ cluster centroid were some different with defect types.

• 한국산업보건학회지
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• 제10권1호
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• pp.18-31
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• 2000

A stack must be designed to 1) reduce or eliminate rainfall or snowfall into a industrial exhaust system, 2) minimize a resistance to flow, 3) maximize the vertical dispersion of the contaminated air and 4) minimize maintenance. The weather cone stacks and the elbow-type stacks are very popular in Korea. But they add some resistance to the exhaust system resulting in reduction of air flow rate, but also deflect the noxious contaminants downward in undiluted form. To solve these problems, ACGIH (American Conference of Governmental Industrial Hygienists) suggested the vertical discharge stack with concentric space between the upper stack with larger diameter and the lower stack with smaller diameter. The preliminary test showed that the vertical discharge stacks did not have the good rainfall protection. The reversed cone were newly devised to satisfy the requirements for the good stack. Subsequently, the amount of rain being penetrated through the stacks was measured while the stacks were simultaneously and naturally exposed to rain in the same area outside. Test results indicate that none of the stacks tested completely exclude rain. The efficiency of rainfall protection and the pressure loss coefficient were compared. The temporary conclusion was reached to the point that the reversed cone stack is the best one. Further research is underway.

• 물과 미래
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• 제23권2호
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• pp.213-225
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• 1990

본 연구는 불규칙한 단면을 가지면서 완곡을 이루는 일반하천에서 공장이나 가정으로부터 방류되는 오염물질의 횡확산현상을 예측하기 위한 수치모형을 제안하였다. 이 수치모형은 자연좌표계와 누적유량개념을 도입하였으며 여기에 필요한 여러가지 요소들을 직접측정하지 않고 컴퓨터 프로그래밍을 통하여 간단히 결과를 얻을수 있는 효율적인 방법을 개발하여 실험결과와 비교검토하므로서 본수치모형의 현지적용성을 검토하였다.

• 수산해양교육연구
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• 제13권2호
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• pp.132-145
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• 2001

The cold discharge from LNG(liquefied natural gas) terminal makes the water temperature around the terminal fall down. This temperature reduction may result in serious changes on marine ecosystem of the coastal area. The numerical model experiments of material transport and tidal circulation in the inner bay, Chinhae Bay are investigated in the dispersion of cold discharge from LNG terminal. The condition of ambient water is exposed to tide, tidal current and cold discharge temperature. Simple numerical model experiments highlight the importance of tidal circulation and cold discharge at each case and some results are discussed. The results of this study can be used as the guideline for the site selection of LNG terminals and long-term marine environmental impact assessment.

• 동의생리병리학회지
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• 제16권4호
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• pp.630-636
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• 2002

After The Yellow Emperor's Canon of Internal Medicine, The text researches of pathologic change to the liver disease concluded the next, 1, The category of liver-disease(肝病) include the Symptoms of abnormality due to vital energy and blood motion, emotion and intention, muscular and reproductive function, and legions around descending liver channel. 2. In the theory that Liver-Yang energy(肝陽氣) is always overproducing, Liver-Yin blood(肝陰血) is always lacking, pathologic characteristics for liver disease is functional change of malfunction of the use of body(體用失調), So nourishing the liver and kidney is used for the principal aspects of a disease. regulating and calm the liver is used for the secondary aspects of a disease as the treatment plan, 3. If malfunctioning of the functions of dispersion and discharge(疏泄), Iiver-energy(肝氣) is becoming degected, So overproduct and overflow of ascent and exhalation of liver-yang(肝陽) is becoming blood are ascending following energy. complete usage of Yin-blood(陰血) is responsible for some kinds of mass formed by blood stasis in the early stage of pathogenesis of liver disease syndrome of the energy system as the progession of disease extravasated blood is forming. the pathologic characteristics is appeared loss of control of the vital energy and blood(體用失調) at the liver disease. 4. Sthenia-syndrome of liver(肝實證) and liver-heat syndrome(肝熱證) is appered that overproducing and overflow of dispersion(疏泄太過) and discharge is responsible for overfunctioning of liver disease or some kinds of heat syndrome such as liver fire(肝火), Sthenia of liver-yang(肝陽上亢), the syndromes of sthenic liver heat(肝實熱) are appered. deficiency of the liver(肝虛證) and cold syndrome of liver(肝寒證) is classified pathologic characteristics of cold and heat, deficiency and excess that regression of sensory, motor, mental due to lack of dispersion and discharge(疏泄不及), or intruding of the cold miasma, are degected. 5. The liver is close relation of physiologic function and internal organ such as spleen, stomach, lung, heart, kidney, gall bladder by the meridian channels, because of property of wind Zang, rapid progession is classified by phthologic charateristics.

• 항공우주기술
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• 제10권1호
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• pp.63-69
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• 2011

본 연구에서는 기존의 가스발생기 사이클 액체로켓 엔진 모드해석 프로그램(GEMAT)을 개선하여 엔진 구성품이 가지는 성능 분산으로 인한 시스템 수준에서의 성능 분산을 계산 하는 프로그램을 개발하였다. 본 프로그램을 이용하여 엔진 내부 인자의 성능 분산을 보정하기 위해 필요한 각 배관에서의 보정용 여유차압을 산정하는 방법을 제시하였다. 또한 이를 활용하여 기존의 엔진 보정 방법을 보완하여 보정용 차압을 최적화하고 이를 통해 펌프 토출압을 감소시키거나 연소실의 연소압을 높임으로써 전체 엔진의 비추력 향상을 꾀할 수 있는 보정 방법을 제시하였다.

• 한국표면공학회지
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• 제41권5호
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• pp.194-198
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• 2008

Several methods for improving dispersion of carbon nanotubes (CNTs) have been investigated. CNTs modified by acids and hydrogen peroxide ($H_2O_2$) showed improved dispersion. From SEM micrographs and photos of dispersion, CNTs modified with nitric acid and $H_2O_2$, showed no agglomeration in solution even standing for 4 months, which means successfully improved dispersion property. TEM micrographs of surface modified single CNT treated with 69% $HNO_3$ in boiling acid solution as the optimum method were obtained. For confirmation of CNTs' application to EDLC electrode materials, characteristics of EDLC have been analyzed by cyclic voltammetry curve, specific capacitance of unit cell, electrode discharge curves and AC impedance curve. From the results, it could be confirmed that electrochemical properties of CNTs were enhanced after surface modification with 69% $HNO_3$ acid treatment.

• 물과 미래
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• 제28권5호
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• pp.151-162
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• 1995

자연하천에서 오염물질의 횡확산과정은 정확하게 모의하기 위하여 2차원 유관확산모형을 개발하였다. 본 모형에서는 독립변수로서 횡방향거리 대신에 횡방향누가유량을 도입하였고, 하천의 주흐름을 따라 좌표축을 설정하는 자연좌표계를 사용하였다. 유도한 유관확산방정식을 풀기 위한 수치방법으로서 Eulerian-Lagrangian method를 이용하였다. 유관확산방정식을 연산자분리방법을 이용하여 이송을 지배하는 방정식과 확산을 지배하는 방정식으로 분리하였다. 그리고 이송방정식은 Eulerian 계산격자상에서 특성곡선법을 이용하였고 확산방정식은 중앙차분법을 이용하여 수치모의 하였다. 본 연구에서는 이송방정식의 풀이에서 사용되는 보간다항식으로 cubic spline 보간다항식을 이용하였다. 본 연구에서 개발한 모형을 적용하여 실제 자연하천에서 행해진 정상상태의 색소실험 결과를 모의한 결과개발된 모형이 우수한 거동을 보이고 있음이 밝혀졌다.