• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.229-233
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• 2003

The soundproof barrier used to reduce the traffic and rail noise is usually designed to the point of view of the acoustic performance such as absorption ratio and transmission loss. But, because the surface of soundproof barrier is polluted by the air pollutant or discharge gas of automobiles, so it's surface cleary maintained by the periodic washing with detergent. But in this case the environmental pollution and the working expenses are worried. So, the objective of this study is to develope the soundproof panel with the self-cleaning properties only by raining.

• Korean Chemical Engineering Research
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• 제59권1호
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• pp.100-105
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• 2021

본 연구는 적은 비용으로 분석 장치 없이 질병 진단 및 경과를 모니터링할 수 있는 종이-기반 분석 장치(paper-based analytical device, PAD)를 제작하기 위해 polydimethylsiloxane (PDMS) 블레이드 코팅 방법을 제안하였다. PAD 디자인은 레이저 커팅 기술로 쉽게 몰드에 적용할 수 있으며, 제작된 몰드로 블레이드 코팅을 수행하여 완전한 소수성 장벽 형성에 필요한 조건을 확립하였다. 코팅 조건인 잉크의 두께와 종이와의 접촉시간에 따라 PDMS 소수성 장벽의 구조와 친수성 채널의 크기 변화를 분석하여 안정적으로 소수성 장벽을 형성할 수 있는 조건을 최적화하였다. 최적화된 방법을 바탕으로 PAD를 제작하여 특별한 분석기기 없이 단백질, 당, 메탈이온을 검출하여 바이오센서에 응용가능함을 증명하였다.

• 대한화장품학회지
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• 제24권3호
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• pp.6-16
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• 1998

Ceramides are currently emerging as the major skin care ingredients due to !heir barrier properties in the stratum corneum of the human skin. Thus, major cosmetic companies have developed synthetic ceramide analogs for their own use. In this study, several ceramide mimic compounds , new skin barrier lipids, were designed and synthesized, and their physical and biological properties were investigated to evaluate their skin care capability. Several structures were designed from the variation of hydrophobic alkyl chain and hydrophilic moiety by the use of molecular modeling software. The selected targets were synthesized, and their properties and activities were studied as the pure form, in the emulsion, or in the lamellar mixture containing cholesterol and fatty acid. Some compounds, such as 1,3-bis(N-(2-hydroxyethyl)-palmitoylamino)-2-hydroxypropane, enhanced the restoration of skin barrier damaged by SDS(sodium dodecyl sulfate), and by acetone treatment. The rate of restoration was comparable to that of natural ceramides. The synthesized compounds alleviated SDS induced skin irritation and facilitated lamellar phase liquid crystal formation. The treatment of 1,3-Dis(N-(2-hydroxyethyl)-palmitoylam ino)-2-hyd roxypropane on the acetone damaged skin revealed that the compound promoted the recovery of intercellular lipid lamellar structure of stratum corneum layer. The replacement of palmitoyl groups of the compound with shorter alkyl chain gave lower emulsion viscosity and liquid crystal density, suggesting easier formulation and poorer barrier activity. Most of the synthesized compounds were non-irritable in various toxicological tests proving that they can be safely introduced to the skin care formulations.

• Carbon letters
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• 제14권4호
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• pp.247-250
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• 2013

In this study, we present a facile method of fabricating graphene oxide (GO) films on the surface of polyimide (PI) via layer-by-layer (LBL) assembly of charged GO. The positively charged amino-phenyl functionalized GO (APGO) is alternatively complexed with the negatively charged GO through an electrostatic LBL assembly process. Furthermore, we investigated the water vapor transmission rate and oxygen transmission rate of the prepared (reduced GO $[rGO]/rAPGO)_{10}$ deposited PI film (rGO/rAPGO/PI) and pure PI film. The water vapor transmission rate of the GO and APGO-coated PI composite film was increased due to the intrinsically hydrophilic property of the charged composite films. However, the oxygen transmission rate was decreased from 220 to 78 $cm^3/m^2{\cdot}day{\cdot}atm$, due to the barrier effect of the graphene films on the PI surface. Since the proposed method allows for large-scale production of graphene films, it is considered to have potential for utilization in various applications.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1999년도 춘계학술대회 논문집
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• pp.349-352
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• 1999

We have investigated the electrical characteristics of arachidic acid($C_{20}$), stearic acid(C_{18} and palmitic acid($C_{16}$) Langmuir-Blodgett(LB) films because the fatty acid systems have a same hydrophilic group and a different hydrophobic one (alkyl chain length). In this work, fatty acid systems were used as LB films and the status of the deposited films were confirmed by evaluating the capacitance and I-V characteristics. The conductivity of $C_{20}$, C_{18} and $C_{16}$ LB films obtained from I-V characteristics were about 5x $10^{15}$, 3x $10^{14}$ and 9x $10^{14}$[S/cm], espectively. These results have shown the insulating materials and could control the conductivity by changing the length of alkyl chain. Also, we have confirmed that the barrier height of fatty acid systems were about 1.32- 1.40[eV] and the relative dielectric constant were about 2.9~4.2. These values were almost the same ones obtained from dielectric characteristics.

• 한국섬유공학회:학술대회논문집
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• 한국섬유공학회 2002년도 봄 학술발표회 논문집
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• pp.187-190
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• 2002

Poly(vinyl alcohol) (PVA) is a representative hydrophilic and water-soluble polymer and widely employed in various applications such as fibers for clothes and industries, films, membranes, medicines for drug delivery system, and cancer cell-killing embolic materials. Moreover, PVA fibers, gels, and films are potentially high-performance materials because they have high tensile and impact strengths, high tensile modulus, high abrasion resistance, excellent alkali resistance, and oxygen barrier property which are superior to those of any known polymers[1,2]. (omitted)

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 C
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• pp.583-585
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• 2000

This study reports the fluidic handling method using hydrophobic patterns inside PDMS microchannels. In order to obtain hydrophobic patterns, we pattern fluorcarbon(FC) film surfaces by lift-off process. FC films are deposited by spin coating method and plasma polymerization method. Hydrophobic surfaces are used as the barriers to control fluid flow. Injected liquid is spontaneously filled up inside PDMS-microchannels by the capillary action. Liquid flow stops when it meets hydrophobic regions which can be the barrier against fluid flow. Then, again, when liquid is pressurized externally, liquid can move toward another hydrophilic region by external air pressure. Contact angle analyses are performed on fluorocarbon films to estimate the wettability of film surfaces.

• 반도체디스플레이기술학회지
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• 제8권2호
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• pp.15-21
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• 2009

Atmospheric pressure plasma equipment was successfully applied to the flip chip BGA manufacturing process to improve the uniformity of flux printing process. The problem was characterized as shrinkage of the printed flux layer due to insufficient surface energy of the flip chip BGA substrate. To improve the hydrophilic characteristics of the flip chip BGA substrate, remote DBD type atmospheric pressure plasma equipment was developed and adapted to the flux print process. The equipment enhanced the surface energy of the substrate to reasonable level and made the flux be distributed over the entire flip chip BGA substrate uniformly. This research was the first adaptation of the atmospheric pressure plasma equipment to the flip chip BGA manufacturing process and a lot of possible applications are supposed to be extended to other PCB manufacturing processes such as organic cleaning, etc.

• Journal of Pharmaceutical Investigation
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• 제30권3호
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• pp.179-189
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• 2000

Clebopride malate(Cm) is a new benzamide drug which has a potent central antidopaminergic activity possessing antiemetic and anxiolytic properties. A purpose of this study was to assess the feasibility of formulating sustained release preparation by dispersing a drug in hydrophilic polymeric matrices and double layered tablets(DLT), using HPMC, carbopol, PEO, PVP/VA and other polymers as a rate controlling barrier. The matrix and DLT showed optimum dissolution pattern up to 8 hours and the contents of polymer were optimized at 30% level in this preparation. After an oral administration in beagle dog, Cm concentration was determined by use of GC-ECD and pharmacokinetic parameters were calculated by Vallner's method. The AUC of DLT showed similar results and the duration of action was increased 55% compared to that of regular release dosage form. The calculated absorption rate effectiveness(ARE) and controlled release effectiveness(CRE) for DLT increased 50% compared to that of matrix, the overall effectiveness(E) of this product appears to be about 70%. in vivo effectiveness test, DLT showed significant differences from control on antiemetic action of Cm. In consequence, it was possible to conclude that double layered tablet might be a good candidate for the sustained release dosage forms.

• 공업화학
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• 제32권4호
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• pp.371-378
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• 2021

고체 표면의 박테리아 부착억제를 목적으로 고분자를 이용한 친수성 표면 개질 연구가 주목을 받고 있다. 부착억제기능은 세포독성이 아닌 작용으로 바이오필름 형성의 초기단계 방지를 목적으로 하며 친수성 또는 이온성 고분자가 도입된 고체 표면은 단백질, 박테리아 등 생물 개체의 부착방지에 효과적이다. 이는 표면에서의 친수층 형성으로 인한 표면 장벽 형성, 고분자 사슬에 의한 반발력과 삼투압성 응력 작용, 그리고 이온성 고분자와 세포 표면의 정전기적 상호작용에 기인한다. 부착억제를 위한 고분자의 표면 도입은 주로 표면 기능기와의 결합을 이용한 접합 방식과 자연모방 접착 기능기를 활용한 침적 방식으로 이루어지고 있다. 본 총설에서는 표면 도입 시 부착억제 기능을 보이는 대표적인 고분자의 종류, 코팅방법, 및 항균 특성을 소개하고 향후 공공시설, 산업 등으로의 대면적 응용을 위한 고려사항들을 다루고자 한다.