• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.216-216
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• 1999

The usage of a stationary plasma thruster (SPT) ion source, invented previously for space application in Russia, in experiments with surface modifications and film deposition systems is reported here. Plasma in the SPT is formed and accelerated in electric discharge taking place in the crossed axial electric and radial magnetic fields. Brief description of the construction of specific model of SPT used in the experiments is presented. With gas flow rate 39ml/min, ion current distributions at several distances from the source are obtained. These was equal to 1~3 mA/$\textrm{cm}^2$ within an ion beam ejection angle of $\pm$20$^{\circ}$with discharge voltage 160V for Ar as a working gas. Such an extremely high ion current density allows us to obtain the Ti metal films with deposition rate of $\AA$/sec by sputtering of Ti target. It is shown a possibility of using of reactive gases in SPT (O2 and N2) along with high purity inert gases used for cathode to prevent the latter contamination. It is shown the SPT can be operated at the discharge and accelerating boltages up to 600V. The results of presented experiments show high promises of the SPT in sputtering and surface modification systems for deposition of oxide thin films on Si or polymer substrates for semiconductor devices, optical coatings and metal corrosion barrier layers. Also, we have been tried to establish in application of the modeling expertise gained in electric and ionic propulsion to permit numerical simulation of additional processing systems. In this mechanism, it will be compared with conventional DC sputtering for film microstructure, chemical composition and crystallographic considerations.

• Steel and Composite Structures
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• 제7권6호
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• pp.457-468
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• 2007

Analytical and experimental investigation on dynamic properties of extra lightweight concrete sandwich beams reinforced with various lay ups of carbon reinforced epoxy polymer composites (CFRP) are discussed. The lightweight concrete used in the core of the sandwich beams was made up of extra lightweight aggregate, Lica. The density of concrete was half of that of the ordinary concrete and its compressive strength was about $100Kg/cm^2$. Two extra lightweight unreinforced (control) beams and six extra lightweight sandwich beams with various lay ups of CFRP were clamped in one end and tested under an impact load. The dimension of the beams without considering any reinforcement was 20 cm ${\times}$ 10 cm ${\times}$ 1.4 m. These were selected to ensure that the effect of shear during the bending test would be minimized. Three other beams, made up of ordinary concrete reinforced with steel bars, were tested in the same conditions. For measuring the damping capacity of sandwich beams three methods, Logarithmic Decrement Analysis (LDA), Hilbert Transform Analysis (HTA) and Moving Block Analysis (MBA) were applied. The first two methods are in time domain and the last one is in frequency domain. A comparison between the damping capacity of the beams obtained from all three methods, shows that the damping capacity of the extra lightweight concrete decreases by adding the composite reinforced layers to the upper and lower sides of the beams, and becomes most similar to the damping of the ordinary beams. Also the results show that the stiffness of the extra lightweight concrete beams increases by adding the composite reinforced layer to their both sides and become similar to the ordinary beams.

• Composites Research
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• 제24권5호
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• pp.39-43
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• 2011

탄소나노튜브로 보강된 고분자 수지에 대한 연구는 지난 20년간 활발히 수행되어 왔다. 또한 이를 이용하여 탄소섬유복합재의 물성을 증대시키기 위한 연구도 최근 그 영역을 넓혀가고 있다. 탄소섬유복합재는 탄소섬유의 비약적인 발전으로 섬유 방향의 기계적 물성은 상당히 만족할 만한 수준에 도달했으나, 수지에 의해 좌우되는 기계적 물성은 아직 기대에 못미치고 있다. 특히, 층간의 분리 (delamination)는 탄소섬유복합재의 가장 전형적이며 치명적인 파손의 원인중 하나이다. 이 층간분리에 대한 저항성을 알아보는 모드 1 파괴인성 실험 (혹은 double cantilever beam, DCB test)을 다양한 작용기로 기능화된 SWNT가 첨가된 탄소섬유복합재 시편에 대하여 수행하였다. 부직포 형태의 탄소나노튜브층을 이용한 시편의 경우 10.6%의 파괴인성 증대를 보였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.95-95
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• 2014

An OLED(Organic Light-Emitting Diode) device based on the emissive electroluminescent layer a film of organic materials. OLED is used for many electronic devices such as TV, mobile phones, handheld games consoles. ULVAC's mass production systems are indispensable to the manufacturing of OLED device. ULVAC is a manufacturer and worldwide supplier of equipment and vacuum systems for the OLED, LCD, Semiconductor, Electronics, Optical device and related high technology industries. The SMD Series are single-substrate sputtering systems for deposition of films such as metal films and TCO (Transparent Conductive Oxide) films. ULVAC has delivered a large number of these systems not only Organic Evaporating systems but also LTPS CVD systems. The most important technology of thin-film encapsulation (TFE) is preventing moisture($H_2O$) and oxygen permeation into flexible OLED devices. As a polymer substrate does not offer the same barrier performance as glass substrate, the TFE should be developed on both the bottom and top side of the device layers for sufficient lifetimes. This report provides a review of promising thin-film barrier technologies as well as the WVTR(Water Vapor Transmission Rate) properties. Multilayer thin-film deposition technology of organic and inorganic layer is very effective method for increasing barrier performance of OLED device. Gases and water in the organic evaporating system is having a strong influence as impurities to OLED device. CRYO pump is one of the very useful vacuum components to reduce above impurities. There for CRYO pump is faster than conventional TMP exhaust velocity of gases and water. So, we suggest new method to make a good vacuum condition which is CRYO Trap addition on OLED evaporator. Alignment accuracy is one of the key technologies to perform high resolution OLED device. In order to reduce vibration characteristic of CRYO pump, ULVAC has developed low vibration CRYO pumps to achieve high resolution alignment performance between Metal mask and substrate. This report also includes ULVAC's approach for these issues.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.394.2-394.2
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• 2014

We fabricated highly transparent and flexible Ti doped In2O3 (TIO)/Ag nanowire(NW)/TIO (TAT) multilayer electrodes by linear facing target sputtering (LFTS) and brush-painting for used as flexible for anode organic solar cells(FOSCs). The characteristics of TAT transparent anode as a function of number of brush-painting cycles was also investigated. At optimized conditions we achieved highly flexible TAT multilayer electrodes with a low sheet resistance of $9.01{\Omega}/square$ and a high diffusive transmittance more than 80% in visible region as well as superior mechanical stability. The effective embedment of the Ag NW network between top and bottom TIO films led to a metallic conductivity, high transparency. Based on FE-SEM HRTEM, and XRD analysis, we can find that the Ag NW network was effectively embedded between top and bottom TIO layers due to good flexibility of Ag NW, the TAT multilayer showed superior flexibility than single TIO layer. Successful operation of FOSCs with high power conversion efficiency of 3.01% indicates that TAT hybrid electrode is a promising alternative to conventional ITO electrode for high performance FOSCs.

• 분석과학
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• 제29권5호
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• pp.225-233
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• 2016

입자 표면에 고분자를 화학적으로 접목하는 것은 수용성 액체 이상 시스템(ATPS)과 같이 분리된 액체 층에서 마이크로/나노입자를 선택적으로 분배시키는데 중요한 구실을 한다. 본 연구에서는 덱스트란, 폴리에틸렌 글리콜, 알부민을 화학적으로 폴리스티렌 자성 마이크로입자 표면에 화학적으로 부착시켰다. 분배 현상을 역전시킬 수 있는 긴 고분자 사슬의 부착은 일차 아민 작용기를 가진 다양한 고분자를 p-톨루엔술폰산(토실)기를 부착시킨 폴리스티렌 자성 마이크로입자와의 S_N2 치환에 의해 간단히 수행될 수 있었다. 이 후 적외선 현미경을 사용하여 마이크로입자의 표면 변화의 유무를 검사하였다. 반응 후 입자들은 세 가지 폴리머 모두 N-H 신축 진동 피크를 보였으며 대부분의 주요 피크들의 위치는 반응 전후에 유사하였으나 지문 영역에서 구별 가능한 차이를 보였다.

• 한국화재소방학회논문지
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• 제24권2호
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• pp.21-30
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• 2010

본 연구는 화학보호복 원단들에 대하여 내화학성 및 난연성을 조사하기 위하여 ASTM 및 ISO의 방법을 이용하여 내화학성 및 화재위험성시험을 실시하였다. 시험결과 폴리에틸렌의 경우 전혀 난연성이 없는 것으로 분석되었지만 고무에 데카브롬 등 난연성 물질이 첨가된 불소고무 원단이 뛰어난 난연성을 보였다. 특히 현재 소방용 방열복으로도 사용되고 있는 알루미늄 필름에 아라미드원단을 라미네이팅한 원단이 가장 뛰어난 난연성을 보였다. 하지만 내화학성에 있어 알루미늄은 4% NaOH에 부식되는 결과를 보이고 있어 이를 극복하기 위한 방안으로는 다층의 베리어성 필름을 사용하는 것이 좋을 것으로 사료된다. 아울러 난연성 시험결과 알루미늄필름과 폴리머 베리어성 필름을 소재로 만든 Dual skin과 불소고무에 난연성 물질이 포함된 것을 소재로 만든 Single skin이 화학보호복으로 적합한 것으로 판단된다. 또한 열방호실험과 열전달지수실험결과 두께의 증가와 다층구조일수록 TPP와 HTI 증가하는 것으로 나타났다. 향후 화학 보호복 원단의 화재위험성 및 내화학성시험 등 지속적 연구와 보완이 적절한 화학보호복 원단 성능개선에 기여할 것으로 기대된다.

• 대한본초학회지
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• 제31권5호
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• pp.41-46
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• 2016

Objectives : The Skin is composed of multiple layers, including the epidermis, dermis, and hypodermis. It provides a vital barrier structure that protects vertebrates from external environmental antigens, solvents, ultraviolet light, microorganisms, toxins, and weather conditions. Although several biological effects of Mori Follium have been reported, beneficial effects of Mori Follium in skin health remain unclear. In this study, we prepared water extract of Mori Follium (MLE) and evaluated the effects on melanin accumulation and expression levels of skin fibril-related proteins.Methods : The cytotoxicities of MLE in B16F10 melanoma and human skin fibroblasts (HSF) were examined by MTT assay. Inhibitory effect of MLE on the α-MSH- and IBMX-induced melanosis in B16F10 melanoma was examined. The expression levels of fibronectin, collagen 1α2, and CCN2 in MLE-treated HSF were analyzed by reverse transcription-polymer chain reaction (RT-PCR) and western blotting.Results : The MLE treatment for 24 h did not affect to the B16F10 and HSF at concentrations of 1, 10, 50, 100, 200, 400 and 800 ㎍/ml. The MLE treatment for 72 h significantly and dose dependently suppressed melanin accumulation in B16F10 melanoma. In addition, the MLE treatment up-regulated expression levels of skin fibril-related genes such as fibronectin, collagen 1α2, and CCN2 in HSF. Our western blot analysis revealed MLE-induced up-regulation of skin fibril-related genes required the activation of CCN2 protein.Conclusions : In conclusion, these findings suggest that the MLE could be used in development of cosmetic natural material of maintaining healthy skin.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제44회 동계 정기학술대회 초록집
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• pp.631-631
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• 2013

Battery has major drawbacks including its size and life expectancy, and environmental problem. As an alternative, energy harvesting is emerging as a potential solution to replace battery along with more energy-efficient IT devices. The idea of harnessing energy from our living environment is sustainable, semi-permanent, and eco-friendly. Also, unlike battery, energy harvester does not require much space to store energy. Therefore, energy harvesting can provide a better source of power for small, portable, and wireless devices. Among various ways of harvesting energy from our surroundings, triboelectricity is chosen due to its potential to be miniaturized, and efficient. Triboelectric effect occurs as two different materials with different polarity of charge separation come into contact through friction, and then become separated so that electric potential difference is achieved. In this research, such characteristic of triboelectricity is used as a way to convert ambient mechanical energy into electric energy.Series of recent researches have shown promising results that the triboelectric energy harvester can be simple and cost effective. However, sufficient electricity level required to operate mobile devices has not yet been achieved.In this research, our group focuses on the design and optimization of triboelectric energy harvesting device to enhance its output. By using maskless lithography to pattern Kapton film and silicon substrate, which is used as a mold for PDMS thin layer, and sputtering metal electrodes on each side, we fabricate and demonstrate different designs of triboelectric energy harvester that utilizes the contact electrification between a polymer thin film and a metal thin foil. In order to achieve optimized result, the output voltage and current are measured under diverse conditions, which include different surface structure and pattern, material, and the gap between layers.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 G
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• pp.2541-2543
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• 1998

This paper describes the fabrication process to fabricate metallic structure of high aspect ratio using LlGA-like process. SU-8 is used as an electroplating mold. SU-8 is an epoxy-based photoresist, designed for ultrathick PR structure with single layer coating [1,2]. We can get more than $100{\mu}m$ thick layer by single coating with conventional spin coater, and applying multiple coating can make thicker layers. In the experiments, we used different kinds of SU-8, having different viscosity. To optimize the conditions for mold fabrication process, experiments are performed varying spinning time and speed, soft-bake, develop and PEB (Post Expose Bake) condition. With the optimized condition, minimum line and space of $3{\mu}m$ pattern with a thickness of $40{\mu}m$ and $4{\mu}m$ pattern with a thickness of $130{\mu}m$ were obtained. Using the patterned PR as a plating mold, metallic structure was fabricated by electroplating. We have fabricated a electroplated nickel comb actuator using SU-8 as plating mold. The thickness of PR mold is $45{\mu}m$ and that of plated nickel is$40{\mu}m$. Minimum line of the mold is $5{\mu}m$. Patterned metallic layer or polymer layer, which has selectivity with the structural plated metallic layer, can be used as sacrificial layer for fabrication of free-standing structure.