• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2001년도 유체기계 연구개발 발표회 논문집
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• pp.373-380
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• 2001

Solid Oxide Fuel Cells (SOFCs) have received considerable attention because of the advantages of high effiiciency, low pollution, cogeneration application and excellent integration with simplified reformer In this paper, we reported development of anode-tubular SOFC by wet process. For making tubular cell, Ni-cermet YSZ anode tube was fabricated using extrusion process, and YSZ electrolyte layer and LSM-YSZ composite, LSM, LSCF cathode layer were coated onto the anode supported tube using slurry dipping process and sintered by co-firing process. By using this tubular cell, we fabricated single cell consisted of the various cathode layers and 4 cell stack with an effective area of $75 cm^2$ per single cell, and evaluated their performance characteristics.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.710-713
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• 2002

In order to improve the power efficiency of multi-layer organic light emitting diodes (OLEDs), electron injection into ETL(electron transport layer) from cathode at the interface between ETL and cathode was enhanced by interposing a proper electron injection layer at the interface. The HTL(hole transport layer) and ETL materials used were N, N'diphenyl- N, N' - bis(3-methylphenyl-1, 1'- biphenyl - 4, 4 'diamine (TPD) and tris (8-hydroxyquinoline) aluminum ($Alq_3$) respectively. Cathodes using co-evaporated Al-CsF, Al-KF, and Al-NaF composites are adopted to enhance the electrical and optical properties of OLEDs. OLEDs with alkaline metal-doped cathode show a luminance of as high as 35,000 cd/$m^2$, and external quantum efficiency about 1.35 %. In addition, they show higher power efficiency at all bias conditions and good reproducibility.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.437-437
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• 2010

DC Hollow cathode 방전은 약 100여 년 전, Paschen에 의해 실험된 이후로 광원, 스퍼터링 공정, 이온빔 소스 등 다양한 분야에 이용되어 왔다. 최근 태양전지용 마이크로 결정질 실리콘 증착 시, RF CCP의 전극에 복수의 홀 혹은 트렌치 구조를 두어 Hollow cathode 방전 효과를 이용하여 향상된 공정 속도로 공정을 진행한다. 그러나 RF-MHCD (Multi hole cathode discharge) 공정을 위한 최적 규격의 홀 기에 관한 연구는 그 중요성과 응용성에도 불구하고 깊게 이루어지지 못한 바 있다. 그러므로 저자는 Capacitively Coupled Plasma (전극 간격 : 4cm, 전극 직경 : 14cm) 장비에서 평면 전극과 10mm 깊이와 각각 3.5mm, 5mm, 7mm, 10mm 직경의 홀이 있는 4개의 전극을 이용하여 Argon RF-MHCD 방전을 관찰하여 조건 별 최적의 홀 전극 디자인을 도출하였다. 실험 조건은 64.5mTorr ~ 645mTorr압력 범위/ 1A~9A이며, 플라즈마는 전극 사이 중앙에 설치한 RF-compensated Langmuir Probe와, 전극과 전기적으로 접촉하는 1000:1 Probe 와 Voltage-Current Probe를 이용하여 측정되었다. 실험 결과 압력 조건 별로, 최적의 전자 밀도를 유도하는 전극 상 홀의 직경이 달라짐을 확인하였다.

• Bulletin of the Korean Chemical Society
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• 제14권5호
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• pp.610-614
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• 1993

Laser induced impedance changes in hollow cathode lamps containing sputtered metal atoms have been employed to measure the spectroscopic properties of metal. This technique, known as optogalvanic spectroscopy, has been shown to be a powerful and inexpensive technique for the investigation of atomic and molecular species. Characteristic optogalvanic signals from hollow cathode lamps (HCL) made of different metal species and induced with a pulsed dye laser were observed, and the dependence of the optogalvanic signal on the discharge current and wavelength of laser was measured. Based on the results obtained, the mechanisms involved in evoking the optogalvanic signals were consisted of single-photon absorption, multi-photon absorption, and photoionization. Moreover the current dependence of the optogalvanic signal indicates that the optogalvanic technique could be one of the most sensitive optical methods of detecting atomic species.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2004년도 학술논문집
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• pp.337-337
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• 2004

As one of researches for the P ＆ T purposes, a basic experiment on the recovery of actinide elements from the mixture with rare earth elements by means of electrorefining using a liquid cadmium cathode in the LiCl-KC1 eutectic melt was carried out. In order to examine the behaviors of electrodeposition of metal ions on a liquid electrode, recovery experiments of rare earth metals resulting from forming electrodeposits were performed by a galvanostatic electrolysis method at various current densities. A cyclic voltammetric technique was applied to determine reduction-oxidation potential of each metal element in the melt and to detect the changes of the multi component melt composition for on-line monitoring. Also, a collaboration study with RIAR was completed to test the preliminary feasibility on a recovery of actinide elements from the mixture with rare earth elements using a liquid cadmium cathode and actinide metals. Experimental results showed that the ratio of actinides to rare earths, 9: 0.5∼1 led to the rare earth content of about 5∼10 wt% in the deposit.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2018년도 춘계학술논문요약집
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• pp.57-57
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• 2018

The electrorefining process is generally composed of two recovery steps in pyroprocessing - the deposit of uranium onto a solid cathode and the recovery of the remaining uranium and TRU elements simultaneously by a liquid cadmium cathode. The liquid cathode processing is necessary to separate cadmium from the actinide elements since the actinide deposits are dissolved or precipitated in a liquid cathode. Distillation process was employed for the cathode processing. It is very important to avoid a splattering of cadmium during evaporation due to the high vapor pressure. In this study, a multi-layer porous round cover was proposed and examined to develop a splatter shield for the Cd distillation crucible. Cadmium vapor can be released through the holes of the shield, whereas liquid drops can be collected in the multiple hemisphere. The collected drops flow on the round surface of the cover and flow down into the crucible. The crucible cover was fabricated and tested in the Cd distiller. The cover was made with three stainless steel round plates with a diameter of 33.50 mm. The distance between the hemispheres and the diameter of the holes are 10 and 1 mm, respectively. About 40 grams of Cd and about 4 grams of Bi was distilled at a reduced pressure for two hours at $470^{\circ}C$. After the Cd distillation experiment, cadmium was not detected and more than 90 % of Bi remained in the ICP-OES analysis. Therefore the crucible cover can be a candidate for the splatter shield of the Cd distillation crucible. Further development of the crucible cover is necessary for the decision of the optimum cover geometry and the operating conditions of the Cd distiller.

• 한국재료학회지
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• 제19권12호
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• pp.667-673
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• 2009

The electrocatalytic characteristics of oxygen reduction reaction of the $PtxM_{(1-x)}$ (M = Co, Cu, Ni) supported on multi-walled carbon nanotubes (MWNTs) have been evaluated in a Polymer Electrolyte Membrane Fuel Cell (PEMFC). The $Pt_xM_{(1-x)}$/MWNTs catalysts with a Pt : M atomic ratio of about 3 : 1 were synthesized and applied to the cathode of PEMFC. The crystalline structure and morphology images of the $Pt_xM_{(1-x)}$ particles were characterized by X-ray diffraction and transmission electron microscopy, respectively. The results showed that the crystalline structure of the Pt alloy particles in Pt/MWNTs and $Pt_xM_{(1-x)}$/MWNTs catalysts are seen as FCC, and synthesized $Pt_xM_{(1-x)}$ crystals have lattice parameters smaller than the pure Pt crystal. According to the electrochemical surface area (ESA) calculated with cyclic voltammetry analysis, $Pt_{0.77}Co_{0.23}$/MWNTs catalyst has higher ESA than the other catalysts. The evaluation of a unit cell test using Pt/MWNTs or $Pt_xM_{(1-x)}$/MWNTs as the cathode catalysts demonstrated higher cell performance than did a commercial Pt/C catalyst. Among the MWNTs-supported Pt and $Pt_xM_{(1-x)}$ (M = Co, Cu, Ni) catalysts, the $Pt_{0.77}Co_{0.23}$/MWNTs shows the highest performance with the cathode catalyst of PEMFC because they had the largest ESA.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2018년도 추계학술논문요약집
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• pp.103-103
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• 2018

The liquid cathode processing is necessary to separate cadmium from the actinide elements in the pyroprocessing since the actinide deposits are dissolved or precipitated in a liquid cathode. Distillation process was employed for the cathode processing owing to the compactness. It is very important to avoid a splattering of cadmium during evaporation due to the high vapor pressure. Several methods have been proposed to lower the splattering of cadmium during distillation. A multi-layer porous round cover was proposed to avoid a cadmium splattering in our previous study. In this study, distillation behavior of $Cd-ZrO_2$ and Cd - Bi systems were investigated to examine a multi-layer porous round cover for the development of the cadmium splatter shield of distillation crucible. It was designed that the cadmium vapor can be released through the holes of the shield, whereas liquid drops can be collected in the multiple hemisphere. The cover was made with three stainless steel round plates with a diameter of 33.50 mm. The distance between the hemispheres and the diameter of the holes are 10 and 1 mm, respectively. Bismuth or zirconium oxide powder was used as a surrogate for the actinide elements. About 40 grams of Cd was distilled at a reduced pressure for two hours at various temperatures. The mixture of the cadmium and the surrogate was distilled at 470, 570 and $620^{\circ}C$ in the crucible with the cover. Most of the bismuth or zirconia remained in the crucible after distillation at 470 and $570^{\circ}C$ for two hours. It was considered that the crucible cover hindered the splattering of the liquid cadmium from the distillation crucible. A considerable amount of the surrogate material reduced after distillation at $620^{\circ}C$ due to the splattering of the liquid cadmium. The low temperature is favorable to avoid a liquid cadmium splattering during distillation. However, the optimum temperature for the cadmium distillation should be decided further, since the evaporation rate decreases with a decreasing temperature.

• 한국산업정보학회논문지
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• 제10권2호
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• pp.76-81
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• 2005

본 연구에서는 차세대 디스플레이 소자로 각광을 받고 있는 유기발광 소자의 전기적인 특성을 해석적으로 접근하였다. 기본적인 OLED의 동작 메카니즘은 일함수(work function)가 낮은 음극(cathode) 전극으로부터 주입된 전자(electron)와 양극(anode) 전극으로 주입된 정공(hole)이 수송층을 지나 발광층으로 유입되어 여기상태(exciton state)를 거치며 재결합함으로써 발광되는 것으로 알려져 있다. 따라서 음극과 양극을 통해 들어오는 수송자(carrier)들이 원활한 전자-정공 쌍(electron - hole pair)을 이루기 위해 다층 박막 구조로 소자를 제작하여 높은 에너지 장벽을 완만하게 만들고 또한 박막의 두께를 조절하여 정공과 전자의 이동도 밸런스(balance)를 맞추어 수송자-전자와 정공-들이 수송층(CTL : carrier transport layer)을 통해 발광층(EML : emitting material layer)으로 주입을 용이하게 만든다 따라서 본 논문에서는 유기 발광소자의 최적의 발광특성을 얻기 위해서는 수치 해석을 통한 가장 높은 발광 효율을 가지게되는 박막의 두께를 예측하고 예측된 유기발광소자의 수치해석 값이 실제 제작된 소자의 특성 값과 일치하여 타당성이 있음을 증명하고자 한다.

• 한국기계가공학회지
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• 제8권3호
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• pp.38-45
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• 2009

Recently, LCD Backlight Unit is being replaced from cold cathode fluorescent lamp(CCFL) to external electrode fluorescent lamp(EEFL) because the EEFL has high energy efficiency and long life. Also, it can reduce energy consumption and weight. So far, external electrode ring for EEFL is produced by sheet metal press forming process. Therefore it had low precision and much material loss. To solve these problems, Multi-Forming process that has five step forming process was invented. However, low productivity is another barrier. Product speed that is controlled by the rotational speed cannot be increased due to the unsatisfied design specification. The reason is that the gap between rolled two edge parts of the sheet plate is tightly inspected. Regarding this factor, the understanding of forming behavior to each process is inevitable. This paper describes the CAE analysis of the multi-forming process by PAM-STAMP.