• Journal of Information Display
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• v.2 no.3
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• pp.66-71
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• 2001

MCFEDs (MOSFET-Contoolled Field Emission Displays) were fabricated to evaluate the validity of MCFEA for display application. The electrical properties of FEAs (Field Emitter Arrays), HVMOSFETs (High-Voltage MOSFETs), and MCFEAs (MOSFET-Controlled Field Emitter Arrays) were measured. The extraction gate voltage of the FEAs to obtain the anode current of 10 nA/tip was around 71 V. The breakdown voltages of the HVMOSFETs were above 81 V for all the samples. The I-V characteristics of the MCFEAs showed that the emission currents of the FEAs were well controlled depending on the control gate voltages of the HVMOSFETs. To avoid the harmful effects during the packaging process, the performance of the MCFEDs was evaluated in a high vacuum chamber. The emission images of the MCFEDs were controlled through very-through operation. From the comparison with a conventional FED, it was proven that the poor uniformity of FED could be improved through the integration with HVMOSFET.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.262-262
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• 2012

A multi-purpose cyclotron, MC50 has been operated to provide multi-ions of proton, deuteron and alpha at Korea Institute of Radiological and Medical Sciences (KIRAMS). Neutron is also produced through the (p,n) nuclear process with a Be target. However, a wide spectrum of current of ions is requested by beam users for carrying their various application fields. Therefore a simulation study is requested on the design of an axial injection system for high current proton and alpha beam extraction for radio-isotope productions and scientific researches. The purpose of this study is seeking a relatively simple method for the MC50 having higher alpha beam capability and also improving proton and deuteron beams currently used. We are considering two possibilities to improve the internal ion source and to install a new external axial injection system. The external injection system will be consisted of an Einzel lens, a steering magnet, a buncher, and a glazer lens placed in front of an inflector, which is located at the center of the main magnet.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.196.2-196.2
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• 2015

There are various issues fabricating the successful and efficient solar cell structures. One of the most important issues is band alignment technique. The solar cells make the carrier in their active region over the p-n junction. Then, electrons and holes diffuse by minority carrier diffusion length. After they reach the edge of solar cells, there exist large energy barrier unless the good electrode are chosen. Many various conductor with different work functions can be selected to solve this energy barrier problem to efficiently extract carriers. Tungsten oxide has large band gap known as approximately 3.4 eV, and usually this material shows n-type property with reported work function of 6.65 eV. They are extremely high work function and trap level by oxygen vacancy cause them to become the hole extraction layer for optical devices like solar cells. In this study, we deposited tungsten oxide thin films by sputtering technique with various sputtering conditions. Their electrical contact properties were characterized with transmission line model pattern. The structure of tungsten oxide thin films were measured by x-ray diffraction. With x-ray photoelectron spectroscopy, the content of oxygen was investigated, and their defect states were examined by spectroscopic ellipsometry, UV-Vis spectrophotometer, and photoluminescence measurements.

• Journal of the Korea Institute of Military Science and Technology
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• v.15 no.3
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• pp.231-240
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• 2012

During the past two decades, Metal Injection Molding(MIM) has become a very competitive technology to fabricate small, precise and complex-shaped parts in large quantities. In this research, the applicability of MIM technology in the mass-production of the high precision fuze parts to save manufacturing cost was investigated. The water-atomized 17-4PH stainless steel powder, one of the best corrosion-resistant high strength materials, was injection-molded into real-shape fuze part and flat tensile specimens. The injection-molded parts were thermally debound in hydrogen gas flow without solvent extraction. Sintering of the debound parts was carried out in vacuum at temperatures ranging from $1150^{\circ}C$ to $1370^{\circ}C$. The sintering behavior, mechanical properties, dimensional precision, corrosion resistance of the MIMed 17-4PH stainless parts were investigated. It was found that almost all the properties of the MIMed parts were comparable to those of the mechanically machined parts. Also, actual military field tests using both MIMed and mechanically machined fuze parts were performed as well and were found to be very successful.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.496-496
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• 2013

스마트윈도우는 디스플레이, 산업용 외장재 등 다양한 분야에 응용이 가능하며, 특히 전기변색을 이용한 디바이스는 나노코팅 기술을 통한 나노입자 및 나노가공제어 등 나노융합기술을 접목할 수 있다. 전기변색 디바이스는유리 또는 필름 기판소재를 통해 제작이 가능하며, 본 연구에서는 전기변색의 산화, 환원반응에 의해 재료의 광특성이 가역적으로 변화할 수 있는 물질을 증착하여 기존 라미네이터 및 Sol-Gel방식의 전해질보다 열화현상에의한 성능저하를 막아주는 박막전해질 코팅 연구이다. 전기변색 소자는 외부 인가 전압(external voltage)에 의해 유도된 전하의 주입(injection) 과 추출(extraction)을 통하여 그 광학적 특성(optical property)을 가역적으로(reversibly) 변 화시킬 수 있는 특징을 가지고 있다. 전기변색소재의 원리를 간략하게 설명하면 대표적인 환원착색 물질인 전기변색층(WO, MoO, Nb2O5 등)으로 Li+ 또는 H+과 전자가 주입되면 전기변색되고 방출 시는 투명하게 되며, 반대로산화착색 물질인(V2O5, NiO, IrO, MnO 등)으로 Li+ 또는 H+과 전자가 방출되면 변색되고 주입되면 투명하게 되는 것이다. 본 연구에서는 전자가 주입되는 환원착색물질인 WO와 함께 Ta2O5박막을 증착하여 광학적특성을 연구하고 박막의 두께 및 전압인가에따른 변색 및 응답속도를 연구하고자 한다.

• Journal of the Korean Professional Engineers Association
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• v.18 no.2
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• pp.6-15
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• 1985

A new process disregraded the H$_2$SO$_4$ treatment process heretofore in use, was developed and substituted for mineral base engine used oil of homemade SAE-30 grade H.V.I., which was used covering 4,500km, as samples, and the following results in research, was obtained. (1) A good quality of rerefinded base oil was obtained through roughly a course of developed processes of vacuum distillation process, solvent extraction process, neutralization treatment process and clay treatment process. (2) Through vacuum distillation process, the size of fine grains of insoluble colloid carbon that is, colloid carbon which was produced by burning of internal combustion engine oil and fuel, could be brought up and precipitated (3) The insoluble matters and admixtures could be easily dispersed and dissolved by mixing and extracting solvent disregarded the H$_2$SO$_4$ treatment process heretofore in use (4) waste matter heretofore called acid sludge in consequence of the process, did not appear at all. accordingly, the environmental pollution could be removed. (5) The troubles of corrosion to copper strip which was faults of the usual used oil refined products and peculiar offensive odor of the rerefined oil, could be solved through the neutralization process. (6) The yield of rerefined oil obtained through a course of processes was over 86 percent, and it is of practical use, not to speak of commercial value.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.39 no.6
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• pp.441-446
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• 2006

Volatile flavor compounds in meat of the blue crab Portunus trituberculatus were compared using vacuum simultaneous steam distillation-solvent extraction (V-SDE) and solid phase microextraction (SPME)/ gas chromatography (GC)/ mass selective detection (MSD) methods. A total of 100 volatile flavor compounds were identified by both methods: 77 by V-SDE and 59 by SPME. These compounds were composed of 17 aldehydes, 12 ketones, 19 alcohols, 5 esters, 4 sulfur-containing compounds, 6 nitrogen-containing compounds, 23 aromatic compounds, 6 hydrocarbons, 2 terpenes, and 6 miscellaneous compounds. Although more compounds were detected using V-SDE than using SPME, the levels of all groups detected, except esters, were higher using SPME than using V-SDE. In addition to trimethylamine, aldehydes, and aromatic compounds, the S- and N-containing compounds with low thresholds are thought to have positive roles for flavors in the meat of the blue crab.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.251.1-251.1
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• 2014

Oraganic Light Emitting Diodes (OLED) 소자의 광추출 효율을 향상시키기 위한 방안으로 나노급 사이즈의 고 굴절률 패턴을 기판의 내부 패턴에 적용하였다. 100 nm 및 300 nm의 직경을 갖는 Si3N4 나노 패턴을 나노 임프린트 리소그래피와 건식 식각 공정을 통하여 OLED의 유리기판에 형성을 하였다. 그리고 Silicon On Glass (SOG) 물질을 패턴이 전사된 기판에 스핀 코팅으로 평탄화 공정을 진행 함으로써 OLED소자의 전기적인 특성이 떨어지는 문제점을 개선하였다. 그러고 나서 Si3N4 나노 패턴이 형성되고 평탄화 공정을 마친 기판상 OLED 소자를 제작하였다. OLED의 발광층에서 발생한 빛은 Si3N4 나노패턴에 의해 산란되어 광 추출 효율을 개선할 수 있다. 본 연구에서 두 가지 종류 100nm, 300nm 높이의 Si3N4 나노패턴으로 높이에 따른 광 추출 효율을 비교하고자 OLED 소자를 제작하였다. 기판에 Si3N4 패턴이 형성된 OLED의 효율은 Si3N4 300nm에서 13.1% 증가하였다.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.134.2-134.2
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• 2014

Photonic crystal solar cells have the potential for addressing the disparate length scales in polymer photovoltaic materials, thereby confronting the major challenge in solar cell technology: efficiency. One must achieve simultaneously an efficient absorption of photons with effective carrier extraction. Unfortunately the two processes have opposing requirements. Efficient absorption of light calls for thicker PV active layers whereas carrier transport always benefits from thinner ones, and this dichotomy is at the heart of an efficiency/cost conundrum that has kept solar energy expensive relative to fossil fuels. This dichotomy persists over the entire solar spectrum but increasingly so near a semiconductor's band edge where absorption is weak. We report a 2-D, photonic crystal morphology that enhances the efficiency of organic photovoltaic cells relative to conventional planar cells. The morphology is developed by patterning an organic photoactive bulk heterojunction blend of Poly(3-(2-methyl-2-hexylcarboxylate) thiophene-co-thiophene) and PCBM via PRINT, a nano-embossing method that lends itself to large area fabrication of nanostructures. The photonic crystal cell morphology increases photocurrents generally, and particularly through the excitation of resonant modes near the band edge of the organic PV material. The device performance of the photonic crystal cell showed a nearly doubled increase in efficiency relative to conventional planar cell designs. Photonic crystals can also enhance performance of other optoelectronic devices including organic laser.

• Proceedings of the Korean Vacuum Society Conference
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• 1996.02a
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• pp.102-102
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• 1996

This paper represents a new type low power High Frequency technological ion source (HF TIS) for ion - beam processing: the surface modification of materials, cleaning of surface, sputtering, coating of thin films, and polishing. The operational principle of HF TIS is based on the excitation of electrostatic waves in plasma located in the external magnetic field. Low power HF TIS with diameter 92 rom gives the opportunity to obtain beams of inert and chemically reactive gases with currents range from 5 to 150 mA (current density $0.015\;~\;3.5\;mA/\textrm{m}^2$) and ion beam energy 100 ~ 2500 eV at a HF power level 10 ~ 150 W. Three grid concave type ion optical system (IOS) is used for extraction and formation ofion beam.n beam.