• 한국재료학회:학술대회논문집
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• 한국재료학회 2010년도 춘계학술발표대회
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• pp.37.1-37.1
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• 2010

The multi-component olivine cathode material, $LiMn_{1/3}Fe_{1/3}Co_{1/3}PO_4$, was prepared via a novel coprecipitation method of the mixed transition metal oxalate, $Mn_{1/3}Fe_{1/3}Co_{1/3}(C_2O_4){\cdot}2H_2O$. The stoichiometric ratio and distribution of transition metals in the oxalate, therefore, in the olivine product, was affected sensitively by the environments in the coprecipitation process, while they are the important factors in determining the electrochemical property of electrode materials with multiple transition metals. The effect of the pH, atmosphere, temperature, and aging time was investigated thoroughly with respect to the atomic ratio of transition metals, phase purity, and morphology of the mixed transition metal oxalate. The electrochemical activity of each transition metal in the olivine synthesized through this method clearly was enhanced as indicated in the cyclic voltammetry (CV) and galvanostatic charge/discharge measurement. Three distinctive contributions from Mn, Fe, and Co redox couples were detected reversibly in multiple charge and discharge processes. The first discharge capacity at the C/5 rate was $140.5\;mAh\;g^{-1}$ with good cycle retention. The rate capability test showed that the high capacity still is retained even at the 4C and 6C rates with 102 and $81\;mAh\;g^{-1}$, respectively.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1999년도 하계학술대회 논문집 E
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• pp.2287-2289
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• 1999

In this paper, a new method for calculating capacitance in multi-electrode system with arbitrarily shape is presented. This new approach based on divergence theorem and Gauss's law is achieved by Surface-Contacted Element(SCE) for Gaussian surface. To evaluate capacitance in multi-electrode system, two dimensional finite element method using only the elements which is contacted one nod (PE: Point-Element) or two nod (FE: Face-Element) with surface is employed. The proposed SCE method has short computing time to calculate capacitance which is because it uses only SCE elements and needs one calculation loop while exiting FEM method in servral loops. This method is verified by application in calculating capacitance using potential detection device model which is composed with anode, cathode, and floating electrode.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2001년도 Proceedings ICPE 01 2001 International Conference on Power Electronics
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• pp.80-83
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• 2001

As a LCD monitor is larger and thinner, a Cold Cathode Fluorescent Lamp (CCFL) for backlight in LCD monitor gradually becomes longer and thinner. The backlight of a large LCD monitor, however, has a limitation in its brightness. In this study, a parallel multi-lamp is used in order to supply enough brightness. Though the CCFLs are made through a detail and equal manufacturing process, they don't have exactly the same features individually in their brightness, frequency, voltage and current. Consequently, it is difficult to have equal brightness at an early lighting condition or during lighting time. In this paper, a parallel multi-lamp which can have the same output under the same condition is designed. For this, 18 inch LCD monitor with four lamps is used. An inverter for multi-lamp driving is also used in this study. The newly designed inverter shows more than $90\%$ efficiency in its brightness input and output. Besides, it is also available for a multi-drive of other lamps.

• 전력전자학회논문지
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• 제10권2호
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• pp.130-137
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• 2005

LCD는 광변조기능을 가지는 수광 소자로서 발광원인 백라이트를 필요로 하는데 일반적으로 냉음극 방전램프(CCFL: Cold Cathode Fluorescent Lamp)가 사용된다. 기존의 권선형 변압기를 이용한 인버터를 구성하여 멀티램프를 구동하고 있지만 이는 코어나 권선 손실에 의한 효율 저하와 부피나 중량의 증가, 그리고 과열에 의한 화재의 위험성을 가지고 있다. 이러한 문제들을 해결하기 위해 본 논문에서는 압전 변압기를 이용한 멀티램프 구동용 인버터를 설계 지침에 따라 구성하였다. 인버터 하나로 압전 변압기를 병렬로 연결하는 방식을 이용하였고, 또한 전류 부담이 적은 외관 전극 형광 램프(EEFL: External Electrode Fluorescent Lamp)를 이용한 멀티램프 구동 방법이 압전 인버터에 적용 가능한지를 확인하였다.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2003년도 하계종합학술대회 논문집 II
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• pp.722-726
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• 2003

본 논문에서는 Porous poly-silicon cold cathode에 의해 전자를 방출하는 Ballistic electron surface-emitting display(BSD)의 전계방출 특성을 실험했다. BSD는 nanocrystalline을 둘러싼 산화막을 multi-tunneling한 전자에 의해 발광이 되는 mechanism이기 때문에 산화막의 두께를 변수로 두어 특성을 실험했다. 900℃에서 1시간에서 3시간까지 30분 간격으로산화 반응을 진행하였으며, leakage current와 emission current의 비로 효율을 나타내었을 때 1시간 30분 동안 산화 반응을 한 시료가 가장 좋은 특성을 나타내었다.

• 한국광학회:학술대회논문집
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• 한국광학회 1991년도 제6회 파동 및 레이저 학술발표회 Prodeedings of 6th Conference on Waves and Lasers
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• pp.41-44
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• 1991

수은 원자의 6 1So - 6 3P1 - 6 2D2, 3D1, 2 - continuum 간의 다단계 광이온화 과정을 수은 hollow cathode lamp를 사용하여 optogalvanic 효과를 관찰하므로써 연구하였다. 단색 단일공명, 이색 단일공명, 이색 이중공명 및 삼색 이중공명 여기과정에 대한 optogalvanic 신호의 time profile 과 스펙트럼을 관측하여 분석했으며, optogalvanic 스펙트럼으로부터 6 3P1 - 61, 3D1 전이들의 상대적 진동차 세기를 측정하였다.

• 한국재료학회지
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• 제17권6호
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• pp.313-317
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• 2007

In-situ micro-channeled multi tubular solid oxide fuel cell(SOFC) was fabricated using multi-pass extrusion process with out side diameter of 2.7 mm and active length of 5 mm that contained 61 individual cells. Cell materials used in this work were NiO-YSZ (50 : 50 vol.%), 8 mol% yttria-stabilized zirconia(8YSZ), $La_{0.8}Sr_{0.2}MnO_3(LSM)$ as anode, electrolyte, and cathode, respectively. The arrangement of each electrode and electrolyte layer in green bodies showed uniformity and integrity after extrusion and sintering. The XRD analysis confirmed that no reaction phases appeared and the microstructure of the electrolyte was fairly dense (relative density > 96%) after sintering.

• 한국소음진동공학회논문집
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• 제19권7호
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• pp.736-745
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• 2009

Fuel cells convert a fuel together with oxygen in a highly efficient electrochemical reaction to electricity and water. Since the electrochemical reaction in the fuel cell stack dose not generate any noise, Fuel cell systems are expected to operated much quieter than combustion engines. However, the tonal noise and the broad band noise caused by a centrifugal compressor and an electric motor cause which is required to feed the ambient air to the cathode of the fuel cell stack with high pressure. In this study, the multi-camber perforated muffler is used to reduce noise. We propose optimized muffler model using an axiomatic design method that optimizes the parameters of perforated muffler while keeping the volume of muffler minimized.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 학술대회 논문집 전문대학교육위원
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• pp.165-169
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• 2007

Organic EL has been expected to adopt to a new styles of technology that make flat display after Tang & Vanslyke made food electric luminescence device in late 1980s. Their studies based on multi layer structure that consists of emitting layer and carrier transporting layer using proper organic material. In this study we made multi layer device using $Eu(TTA)_3(phen)$ as a luminescence material by PVD and investigate luminous properties of each device. But oxidization of organic layer by ITO, energy walls in both pole interface, contaminations of ITO surface, importance of protecting membrane, diffusive dimming of light to cathode organic layer, these causes of degradations are common facts of a macromolecule and micromolecule. We think these degradation caused by the impact of heat and electro-chemical factor, bulk effect and interface phenomenon, and raise a question.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.530-532
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• 2008

Inorganic metal multi-layer(IMML) consisting of Al/Al:SiO/Al was developed as a cathode for OLED to reduce the reflectance generated from ambient light. Device structure of green OLED was ITO/2-TNATA/$\alpha$-NPD/$Alq_3$:C545T/Balq/$Alq_3$/LiF/IMML and IMML was composed of three different layers: thin aluminum layer, aluminum layer doped with silicon monoxide and thick aluminum layer. Average reflectance of green OLED was 9.63% while that of conventional OLED with or without polarizer showed the average reflectance of 8.54% and 66% respectively at visible range from 380 nm to 780 nm.