• KOMUNHWA
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• no.66
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• pp.87-112
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• 2005

Stain removal on ivory has been, for a long time, considered an undesirable treatment in conservation field because ivory is hygroscopic and anisotropic, having different physical properties in different directions. Cyclododecane, which sublimes at room temperature, has been investigated for its use in conservation field since 1995, as a reversible temporary consolidant, sealing agent or coating, water repellent, and barrier layer. This research aims to remove stains on ivory, temporarily protecting the none-stained area or painted area from methanol, acetone or the aqueous cleaning system using cyclododecane as a hydrophobic sealing agent. This research also aims to obtain information regarding whether cyclododecane can be safely and effectively used on archaeological wet ivory. Melted cyclododecane and saturated solutions of cyclododecane in mineral spirits, and hexanes were applied to ivory samples. Application methods, working properties of cyclododecane on ivory, and effect of cyclododecane coating on moisture content of wet ivory were evaluated. The sealing layer formed by molten cyclododecane or by saturated cyclododecane solution in hexane or saturated cyclododecane solution in mineral spirits did not form a secure contact with the surface of the highly polished ivory. The sealing formed with two different layers, in which saturated cyclododecane solution in hexane was applied initially and then molten cyclododecane was applied over the first layer, was found to securely protect the painted area. When the wet samples were kept in 100% RH environments for a month, active mold growths were observed except in the samples sealed with molten cyclododecane. In conclusion, cyclododecane was an efficient hydrophobic sealing agent to protect painting area while cleaning stains on ivory. It also prevented mold growing on wet ivory and wet bone. Evenness of cyclododecane film on ivory will be determined in UV light. Analytical techniques will include visual observation, polarized light microscopy, Scanning Electron Microscope, and Gas Chromatography.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.72-72
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• 2010

Recent development of organic solar cell approaches the level of 8% power conversion efficiency by the introduction of new materials, improved material engineering, and more sophisticated device structures. As for interface engineering, various interlayer materials such as LiF, CaO, NaF, and KF have been utilized between Al electrode and active layer. Those materials lower the work function of cathode and interface barrier, protect the active layer, enhance charge collection efficiency, and induce active layer doping. However, the addition of another step of thin layer deposition could be a little complicated. Thus, on a typical solar cell structure of Al/P3HT:PCBM/PEDOT:PSS/ITO glass, we used Li:Al alloy electrode instead of Al to render a simple process. J-V measurement under dark and light illumination on the polymer solar cell using Li:Al cathode shows the improvement in electric properties such as decrease in leakage current and series resistance, and increase in circuit current density. This effective charge collection and electron transport correspond to lowered energy barrier for electron transport at the interface, which is measured by ultraviolet photoelectron spectroscopy. Indeed, through the measurement of secondary ion mass spectroscopy, the Li atoms turn out to be located mainly at the interface between polymer and Al metal. In addition, the chemical reaction between polymer and metal electrodes are measured by X-ray photoelectron spectroscopy.

• Corrosion Science and Technology
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• v.11 no.1
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• pp.29-36
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• 2012

The resistance spot welding of high strength steel degrades the weldability because of its high strength with rich chemical composition and coating layer to protect from corrosion. During the each resistance welding process the electrodes tip reacts with coating layer, then subsequently deteriorates and shorten electrode life. In this study, the Al-coated HPF (Hot Press Forming) steels and Zn-coated TRIP steels were used to investigate the electrode life for resistance spot welding. Experimental results show that the reactivity of Al-coating on HPF steels to electrode tip surface behaviors different from the conventional Zn-coated high strength steels. The electrode tip diameter and nugget size in electrode life test of Al-coated HPF steels are observed to be constant with respect to weld numbers. For Al-coated HPF steels, the hard aluminum oxide layer being formed during high temperature heat treatment process reduces reactivity with copper electrode during the resistance welding process. Eventually, the electrode life in resistance spot welding of Al-coated HPF steels has the advantage over the galvanized steel sheets.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2006.04a
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• pp.60-61
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• 2006

In this paper, the inorganic-organic thin film encapsulation layer was newly adopted to protect the organic layer from moisture and oxygen. Using the electron beam, Sputter and Spin-Coater system, the various kinds of inorganic and organic thin-films were deposited onto the Ethylene Terephthalate(PET) and their interface properties between organic and inorganic layer were investigated. Results indicates that the SiON/PI/SiON/PI/PET barrier coatings have high potential for flexible organic light-emitting diode(OLEO) applications.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.5
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• pp.588-597
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• 1999

Sokkuram grotto, a UNESCO cultural heritage in Kyongju Korea, was originally covered with crushed rocks over its dome with ventilating holes. The grotto was perfectly preserved for more than 12 centuries until the upper structure was replaced with a concrete dome in the early 20th century to protect from total collapse. Since then, heavy dew formed on the granite surface to seriously damage the sculptures until it was further remodeled with air-conditioning facilities in the 60s. It is considered that the original upper porous structure had a dehumidifying capability. This research is made to unveil the dehumidifying mechanism of the rock layer during the rainy season in that area. A rock layer and a concrete layer are tested in a temperature/humidity-controlled room. No dew formation is observed for the two specimen for continued sunny days or continued rainy days. However, heavy dew formed on the concrete surface for a sunny day after long rainy days. It is thought that the sun evaporates water on the ground and dew is formed at the surface as the highly humid air touches the yet cold concrete. On the contrary, no dew formation is observed for the rock layer at any time. Even in the above worst situation, air flows downward through the cool rock layer and moisture is removed before reaching inside. Temperature measurement, flow visualization, observation of dew formation and measurement of air velocity are made to verify the mechanisms.

• Proceedings of the Korea Information Processing Society Conference
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• 2006.05a
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• pp.1117-1120
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• 2006

Wide applications because of their flexibilities and conveniences of Wireless Mobile Ad-hoc Networks (MANETs) also make them more interesting to adversaries. Currently, there is no applied architecture efficient enough to protect them against many types of attacks. Some preventive mechanisms are deployed to protect MANETs but they are not enough. Thus, MANETs need an Intrusion Detection System (IDS) as the second layer to detect intrusion of adversaries to response and diminish the damage. In this paper, we propose an algorithm for detecting bogus nodes when they attempt to intrude into network by attack routing protocol. In addition, we propose a procedure to find the most optimize path between two nodes when they want to communicate with each other. We also show that our algorithm is very easy to implement in current proposed architectures.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.20 no.5
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• pp.972-978
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• 2016

MACsec is a cryptographic function that operates on Layer 2, the international standard defined in the IEEE 802.1AE. As industries such as IoT(Internet of Things) devices are receiving attention recently are connected to the network and Internet traffic is increasing rapidly, and is exposed to the risk of a variety of Internet attacks. Traditional network security technologies were often made in Layer 3, such as IPsec. However, to be increased as rapidly as the current traffic situation is complicated, and became interested in the security function of protecting the entire traffic instead of for a specific application or protocol. It appeared as these technologies is technology MACsec technology to protect all traffic in Layer 2. In this paper, we propose a Layer 2 security technology adapter MACsec MACsec a technology that allows you to simply and easily add them to the existing Layer 2 networks.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.160-160
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• 2010

Organic electronic devices require a passivation layer to ensure sufficient lifetime. Specifically, flexible organic electronic devices need a barrier layer that transmits less than $10^{-6}\;g/m^2/day$ of water and $10^{-5}\;g/m^2/day$ of oxygen. To increase the lifetime of organic electronic device, therefore, it is indispensable to protect the organic materials from water and oxygen. Severe groups have reported on multi-layerd barriers consisting inorganic thin films deposited by plasma enhenced chemical deposition (PECVD) or sputtering. However, it is difficult to control the formation of granular-type morphology and microscopic pinholes in PECVD and sputtering. On the contrary, atomic layer deoposition (ALD) is free of pinhole, highly uniform, conformal films and show good step coverage. In this study, the passivation layer was deposited using single-process PEALD. The passivation layer, in our case, was a bilayer system consisting of $Al_2O_3$ films and a $TiO_2$ buffer layer on a poly (ether sulfon) (PES) substrate. Because the deposition temperature and plasma power have a significant effect on the properties of the passivation layer, the characteristics of the $Al_2O_3$ films were investigated in terms of density under different deposition temperatures and plasma powers. The effect of the $TiO_2$ buffer layer also was also addressed. In addition, the water vapor transmission rate (WVTR) and organic light-emitting diode (OLEDs) lifetime were measured after forming a bilayer composed of $Al_2O_3/TiO_2$ on a PES substrate.

• Korean Journal of Materials Research
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• v.25 no.5
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• pp.233-237
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• 2015

Silicon oxynitride that can be deposited two times faster than general SiNx:H layer was applied to fabricate the passivation protection layer of atomic layer deposition (ALD) $Al_2O_3$. The protection layer is deposited by plasma-enhanced chemical vapor deposition to protect $Al_2O_3$ passivation layer from a high temperature metallization process for contact firing in screen-printed silicon solar cell. In this study, we studied passivation performance of ALD $Al_2O_3$ film as functions of process temperature and RF plasma effect in plasma-enhanced chemical vapor deposition system. $Al_2O_3$/SiON stacks coated at $400^{\circ}C$ showed higher lifetime values in the as-stacked state. In contrast, a high quality $Al_2O_3$/SiON stack was obtained with a plasma power of 400 W and a capping-deposition temperature of $200^{\circ}C$ after the firing process. The best lifetime was achieved with stack films fired at $850^{\circ}C$. These results demonstrated the potential of the $Al_2O_3/SiON$ passivated layer for crystalline silicon solar cells.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.1
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• pp.191-198
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• 1999

Fifteen varieties of Oryza sativa mainly including those of Korean native rice were exactly cutted into three layers such as L1 layer(the outer part of 92% from rice center), L2 layer(the part of 81∼91% from the rice center) and L3 layer(the inner part of 80% from the rice center) We biologically evaluated the antioxidative effect on the every layer(L1, L2 and L3) of all the varieties, by observing malondialdehyde (MDA) produced by galactosamine in the mouse. L1 layer of some varieties showed significant antiox idative effect, while L2 and L3 layer didn't show the activity. It was also suggested that coloured rice(Suwon 425 and Sanggaehangbyeolna) showed stronger activity than other general rices, probably due to high contents of anthocyanins. Successively, we evaluated antihepatotoxic effect, based on the determination of serum ALT and AST activity. Some varieties of only L1 layer, except for L2 and L3 layer, significantly decreased the serum ALT and AST activity. This finding indicate that oral diet of some raw rice are able to protect hepatotoxicities. Among all the samples tested, L1 layer of Suwon 425 showed the strongest antihepatotoxic effect. From quantitative analysis on ferulic acid derivatives, it was found that the more it enters from the surface into the rice center, the more those secondary metabolites contents were highly reduced. These findings above suggested that Suwon 425 could be a promising candidate for the development of health rice food.