• KSBB Journal
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• v.26 no.4
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• pp.277-282
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• 2011

The penetration of outside material into skin is not easy. It is since the skin, which is a very hard barrier, protects the body against outside chemical and physical stimulation. Microneedle system which can help improve drug penetration into skin is advancing variously in transdermal drug delivery system (TDDS) in the field of skin care. After inserting microneedle into skin by using electrical or artificial forces, it makes microhole and drug penetration easily and induces natural skin rejuvenation. Diffusion and penetration of drug by optical and electrical force of microneedle is better for fast and effective TDDS. This is more developed than the traditional method such as the manual stamp, roller, and meso gun. The drug absorbed into dermal layer by microneedle helps revive and repair damaged skin. In the future, utilization of microneedle for skin care will progress constantly because of its human-friendly biodegradable materials and the development of the no pain microneedle.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.157-157
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• 2015

Recently, the growing interest in organic microelectronic devices including OLEDs has led to an increasing amount of research into their many potential applications in the area of flexible electronic devices based on plastic substrates. However, these organic devices require a gas barrier coating to prevent the permeation of water and oxygen because organic materials are highly susceptible to water and oxygen. In particular, high efficiency OLEDs require an extremely low water vapor transition rate (WVTR) of $1{\times}10^{-6}g/m^2day$. The Key factor in high quality inorganic gas barrier formation for achieving the very low WVTR required ($1{\times}10^{-6}g/m^2day$) is the suppression of defect sites and gas diffusion pathways between grain boundaries. In this study NBAS process was introduced to deposit enhanced film density single gas barrier layer with a low WVTR. Fig. 1. shows a schematic illustration of the NBAS apparatus. The NBAS process was used for the $Al_2O_3$ nano-crystal structure films deposition, as shown in Fig. 1. The NBAS system is based on the conventional RF magnetron sputtering and it has the electron cyclotron resonance (ECR) plasma source and metal reflector. $Ar^+$ ion in the ECR plasma can be accelerated into the plasma sheath between the plasma and metal reflector, which are then neutralized mainly by Auger neutralization. The neutral beam energy is controlled by the metal reflector bias. The controllable neutral beam energy can continuously change crystalline structures from an amorphous phase to nanocrystal phase of various grain sizes. The $Al_2O_3$ films can be high film density by controllable Auger neutral beam energy. we developed $Al_2O_3$ high dense barrier layer using NBAS process. We can verified that NBAS process effect can lead to formation of high density nano-crystal structure barrier layer. As a result, Fig. 2. shows that the NBAS processed $Al_2O_3$ high dense barrier layer shows excellent WVTR property as a under $2{\times}10^{-5}g/m^2day$ in the single barrier layer of 100nm thickness. Therefore, the NBAS processed $Al_2O_3$ high dense barrier layer is very suitable in the high efficiency OLED application.

• Korean Journal of Materials Research
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• v.11 no.3
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• pp.215-220
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• 2001

Amorphous Ti-Si-N films of approximately 200 and 650 thickness were reactively sputtered on Si wafers using a dc magnetron sputtering system at various $N_2$/Ar flow ratios. Their barrier properties between Cu (750 ) and Si were investigated by using sheet resistance measurements, XRD, SEM, RBS, and AES depth profiling focused on the effect of the nitrogen content in Ti-Si-N thin film on the Ti-Si-N barrier properties. As the nitrogen content increases, first the failure temperature tends to increase up to 46 % and then decrease. Barrier failure seems to occur by the diffusion of Cu into the Si substrate to form Cu$_3$Si, since no other X- ray diffraction intensity peak (for example, that for titanium silicide) than Cu and Cu$_3$Si Peaks appears up to 80$0^{\circ}C$. The optimal composition of Ti-Si-N in this study is $Ti_{29}$Si$_{25}$N$_{46}$. The failure temperatures of the $Ti_{29}$Si$_{25}$N$_{465}$ barrier layers 200 and 650 thick are 650 and $700^{\circ}C$, respectively.ely.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.30 no.2
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• pp.61-68
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• 2018

This study was conducted to propose the optimum minimum requirement of cutoff system composed of the impermeable soil layer and vertical barrier in offshore landfill for prevention pollution leakage by seepage, advection, and dispersion numerical analyses under steady state. According to the study results, the minimum requirement of impermeable soil layer is below $1{\times}10^{-6}cm/s$ of hydraulic conductivity with more than 500 cm thickness or a system with equivalent cutoff effect. The minimum requirement of vertical barrier is below $1{\times}10^{-6}cm/s$ of hydraulic conductivity with more than 50 cm thickness or a system with equivalent cutoff effect. In addition, the vertical barrier should be embedded enough to seal securely with the impermeable soil layer for working cutoff effect.

• Journal of the Korean institute of surface engineering
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• v.31 no.1
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• pp.12-23
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• 1998

The Thermal Barrier Coating(TBC) has been used to improve the heat barrier and tribological properties of the aircraft engine and the automobile engine in high temperature. Especially, the high temperature tribological propertied of the cylinder haed and the piston crown of diesel engine was emphasized. Therefore, the purpose of this work was to evaluate the microstructure, tribological propeer in high tempearmal shock resistance and bonding strength of five layer functionally gradient TBC for the applications. The five layerwere composed with 100% ceramic insulating later, 75(ceramic):25 (metal) layer, 50:50 layer, 25:75 layer and 100% metal bonding layer to redude the thermal stress. the YSL and MSL poweders were the insulation ceramics powers. The NiCrAly, Inconel625 and SUS powders were the bonding and mixingg powders for plasma spray process. According to the result of high temperature wear test, the wera resistance of YSZ/NiCrAlY siytem was most out standing at 600 and $800^{\circ}C$. At $400^{\circ}C$, the wear resistance of YSZ/Inconel system was better than others. Wear volume at other temperature because of the low temperature degration of zirconia. The thermal shock mechanism of 5 later is the vertical crack gegration in insulating layer. this means that the initial cracks were generated in the top layer, and then developed into the composite layers during thermal shock test. Finally, these cracks werereached to the interface of coating and substrate and also, these vertioal cracks join with the horizontal cracks of the each layers. The bonding strength of YSZ/NiCrAlY and YSZ/Inconel 5 layer system is better than other 5layer systems. The theramal shock resistance of thermal barrier coating s with 5 layer system is better than that of 3 layers and 2 layers.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.3
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• pp.499-507
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• 2023

The core of the liquefied natural gas (LNG) carrier cargo containment system (CCS) is to store and transport LNG safely under temperatures below -163 degrees Celsius. The secondary barrier of the LNG CCS is adopted to prevent LNG leakage from CCS to the ship's hull structure. Recently, as the size of the LNG CCS increases, various studies have been conducted on the applied temperature and load ranges. The present study investigates the working condition-dependent bonding strength of the PU15 adhesives of the secondary barrier. In addition, the mechanical performance is analyzed at a cryogenic temperature of -170 degrees Celsius, and the failure surface and failure mode are investigated depending on the working condition of the bonded process. Even though the RSB and FSB-based fracture mode was confirmed, the results showed that all the tested scenarios satisfied the minimum requirement of the regulation.

• The Journal of Engineering Geology
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• v.29 no.1
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• pp.13-21
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• 2019

The rainfall intensity-duration curve (I-D curve) was used for selecting the dredging time of sediments behind a debris barrier which is located at the study area in Inje-gun, Kangwon Province. The I-D curve was newly suggested by using the data of rainfall-induced landslides for about 30 years from June to September in Kangwon Province. According to the monitoring results, the landslides have been not occurred during the monitoring period of the dredged sediments management system at the study area, and also all of the rainfall events were located below the I-D curve. The weight of the dredged sediments measured at the management system in the field was increased but the weight increment was small. It means that the increase of the dredged sediments was not the effect of landslide but the effect of soil erosion at the ground surface due to heavy rainfall. The weight of the dredged sediments behind a debris barrier could be known in real time using the rainfall data measured at the management system. Also, when the I-D curve is used with the management system, it is possible to select the optimum dredging time for sediments behind debris barrier.

• Journal of the Korea Safety Management & Science
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• v.10 no.2
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• pp.143-154
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• 2008

With the recent rapid growth of RFID technologies, the Application of RFID systems into the medical or the military industries as well as into the distribution and logistics industry are now attempted continuously. The government and private sectors plan to carry out various small and large scale projects related to RFID systems. However, many companies attempting to apply RFID systems applications into their organizations are encountering many several difficulties because of the lack of installation experience and the absence of an useful guideline. This paper focuses on identification and classification of typical barriers to the successful application of RFID systems according to the five-step method of system application process. Moreover a "barrier map" is produced by conducting a survey and interviews by specialists. In addition, a practical guideline to overcome such barriers is presented and discussed.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.306-314
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• 2003

Engineered barrier test facility is specially designed to demonstrate the performance of engineered barrier system for the near-surface disposal facility under the domestic environmental conditions. Comprehensive measurement systems for the water content, temperature, matric potential are installed within each test cell. In this study, short-term monitoring of the behavior of multi-layered cover system is implemented with artificial rainfall system. The periodic measurement data are collected and analyzed by a dedicated database management system, and provide a basis for performance verification of the disposal cover design.

• Proceedings of the Korean Nuclear Society Conference
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• 2005.05a
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• pp.227-228
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• 2005