• Journal of Physiology & Pathology in Korean Medicine
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• v.29 no.6
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• pp.475-484
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• 2015

In this paper, we studied the anti-oxidative capacities and protective effects of water extract of Gagam-Danguieumja(GDE) against Ultraviolet B(UVB)-induced oxidative damage in human keratinocytes(HaCaT). To evaluate the anti-oxidative activities of GDE, we measured scavenging activities on DPPH radical, hydroxyl radical, hydrogen peroxide, superoxide anion, lipid peroxidation and reducing power of GDE. To detect the protective effects of GDE against UVB, we irradiated with 40 mJ/㎠`s UVB to HaCaT cells then we measured reactive oxygen species(ROS) generation, apoptotic bodies and cell viability using DCFH-DA assay, Hoechst 33342 staining and MTT assay. GDE showed the anti-oxidative activities by scavenging DPPH radical, hydroxyl radical, hydrogen peroxide, superoxide anion, lipid peroxidation. Also GDE showed high reducing values. GDE reduced oxidative stress conditions by inhibition of ROS expression. Also the cell apoptosis by UVB-induced oxidative conditions was decreased by GDE treatment. These results could suggest that GDE had anti-oxidative activities and exhibited protective effects against UVB on HaCaT cells. GDE would be useful for the development of cosmetics treating UVB-induced skin aging.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.3
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• pp.264-269
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• 2016

A simple dry chemical approach was developed in order to load palladium (Pd) as a promoter on Pt/gas diffusion electrode (GDE) for polymer electrolyte membrane fuel cell (PEMFC). Palladium(II) bis (acetylacetonate), $Pd(acac)_2$ was sublimed, penetrated into Pt/GDE and then reduced to Pd nanoparticles simultaneously without any reducing agent and any solvent in a glass reactor of $N_2$ atmosphere at $180^{\circ}C$ for 3, 5 and 15 min. Pd distribution was analyzed by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS), and I-V curve was estimated by using a unit cell with $5{\times}5cm^2$ active area.

• The Journal of Internal Korean Medicine
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• v.34 no.4
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• pp.339-348
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• 2013

Objectives : Danguieumja is a traditional medicinal prescription to treat skin disease. It was commonly used for the treatment of itching, chronic urticaria and atopic dermatitis in Korea by the addition or omission of several herbs. This study investigated the anti-inflammatory potential of Gagam-Danguieumja (GDE) water extract. Methods : We examined the effects of GDE on the lipopolysaccharide (LPS)-induced production of nitric oxide (NO) in a murine macrophage cell line, RAW 264.7 cells. Results : GDE inhibited production of NO in a dose dependent manner and also decreased the expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2). As a possible molecular mechanism of anti-inflammatory effect increased phosphorylation of mitogen-activating protein kinases (MAPK) by LPS were blocked by GDE treatment. Conclusions : These results suggest that GDE has an anti-inflammatory therapeutic potential through the inhibition of MAPK phosphorylation, thereby decreasing the expression of pro-inflammatory genes.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.9
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• pp.1504-1510
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• 2016

The aim of this study is to improve properties both glass transition temperature($T_g$) and coefficient of thermal expansion(CTE) using epoxy/micro-nano alumina composites with adding glycerol diglycidyl ether (GDE:1,2,3,5g). This paper deals with the effects of GDE addition for epoxy/micro alumina contents (40, 50, 60wt%)+surface modified nano alumina(1_phr) composites. 20 kinds specimen were prepared with containing micro, nano alumina and GDE as a micro composites(10, 20, 30, 40, 50, 60, 70wt%) or a nano/micro alumina composites(1phr/40, 50, 60wt%). Average particle size of nano and micro alumina used were 30nm and $1{\sim}2{\mu}m$, respectively. The micro alumina used were alpha phase with Heterogeneous and nano alumina were gamma phase particles of spherical shape. The glass transition temperature and coefficients of thermal expansion was evaluated by DSC and TMA. The glass transition temperature decreased and coefficients of thermal expansion become smaller with filled contents of epoxy/micro alumina composites. On the other hand, $T_g$ and CTE as GDE addition variation(1,2,3,5g) of epoxy/micro-nano alumina composites decreased and increased respectively.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.05a
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• pp.303-308
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• 2002

A governing differential equation (GDE) of PSC flexural member with constant eccentricity considering the long-term losses including concrete creep, shrinkage, and PS steel relaxation is derived based on the two approaches. The first approach utilizes the force and moment equilibrium equations derived based on the geometry of strains of the uniform and curvature strains while the second one utilizes the principle of minimum total potential energy formulation. The identity of the two GDE's is verified by comparing the coefficients consisting of the GDE's. The boundary conditions resulting from the functional analysis of the variational calculus are investigated. Rayleigh-Ritz method provides a way to get the explicit form of the continuous deflection function in which the total potential energy is minimized with respect to the unknown coefficients consisting of the trial functions. As a closure, the analytically calculated results are compared with the experiments and show good agreements.

• The Journal of the Acoustical Society of Korea
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• v.20 no.4E
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• pp.24-30
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• 2001

This paper describes a fast harmonic estimation, referred to as Delta Adjustment (DA), using a low resolution pitch. The presented DA method is based on modification of the Generalized Dual Excitation (GDE) technique[1] which was proposed to improve speech enhancement performance. We introduce the GDE technique and modify it to be suitable for low bit rate harmonic coding that uses only an integer pitch estimate. Unlike the GDE, the DA matches a frequency-warped version of the original spectrum that conforms to a fixed pitch at all harmonic bands. In addition, complexity and performance of the presented method are described in comparison with those of the conventional Fractional Pitch (FP) based harmonic estimation. Experimental results showed that the DA algorithm significantly reduces the complexity of the FP method while maintaining the performance.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.10
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• pp.613-619
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• 2016

The aim of this study is to improve of dielectric properties using epoxy/nano alumina composites with adding glycerol diglycidyl ether (GDE:1,2 g). This paper deals with the effects of dielectric properties(${\epsilon}^{\prime}_r$ and $tan{\delta}$) for epoxy/nano alumina contents (1,3 phr) and GDE addition (1,2 g)composites. 5 kinds specimen were prepared with containing epoxy resins, epoxy nano alumina composites. Average particle size of nano used were 30 nm. The nano alumina used were gamma phase particles of spherical shape. The suppression of epoxy chain motion by addition of nano alumina+GDE decreased dielectric loss and relative permittivity magnitude.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.12
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• pp.796-802
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• 2016

In order to develop an electrical insulation material for gas GIS (insulation switch gear) spacer, 4 types of epoxy/micro-alumina (40, 50, 60, 70 wt%) composites and 9 types of epoxy/nano-alumina (1, 3, 5 g)/micro-alumina (40, 50, 60, 70 wt%) composites were prepared and tensile test was carried out. In here, nano-alumina was previously surface-treated with GDE (glycerol diglycidyl ether). As micro-alumina and GDE-treated nano-alumina contents increased, tensile strength increased and the highest value was shown in the system with 3 g GDE-treated nano-alumina.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.40-40
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• 2011

반도체 소자의 미세화와 더불어 세정공정의 중요성이 차지하는 비중이 점점 커지고, 이에 따라 세정 기술 개발에 대한 요구가 증대되고 있다. 기존 세정 기술은 화학약품 위주의 습식 세정 방식으로 패턴 손상 및 대구경화에 따른 어려움이 있다. 따라서 건식세정 방식이 활발하게 도입되고 있으며 대표적인 것이 에어로졸 세정이다. 에어로졸 세정은 기체상의 작동기체를 이용하여 에어로졸을 형성하고 표면 오염물질과 직접 물리적 충돌을 함으로써 세정한다. 하지만 이 또한 생성되는 에어로졸 내 발생 입자로 인해 패턴 손상이 발생하며 이러한 문제점을 극복하기 위하여 대두되는 것이 가스클러스터 세정이다. 가스 클러스터란 작동기체의 분자가 수십에서 수백 개 뭉쳐 있는 형태를 뜻하며 이렇게 형성된 클러스터는 수 nm 크기를 형성하게 된다. 그리고 짧은 시간의 응축에 의해 수십 nm 크기까지 성장하게 된다. 에어로졸 세정과 다르게 클러스터가 성장할 환경과 시간을 형성하지 않음으로써 작은 클러스터를 형성하게 되며 이로 인해 패턴 손상 없이 오염입자를 제거하게 된다. 이러한 가스 클러스터 세정을 최적화하기 위해서는 설계 단계부터 노즐 내부 유동의 수치해석에 기반한 입자 크기 분포를 계산하여 반영하는 것이 필요하다. 따라서 본 연구에서는 상용 수치해석 프로그램을 이용하여 세정 환경을 조성하는 조건에서의 노즐 내부 유동을 해석하고, 이를 통해 얻어진 수치를 이용하여 aerosol general dynamic equation (GDE)를 계산하여 발생하는 클러스터의 크기 분포를 예측하였다. GDE 계산 시 입자의 크기 분포를 나타내기 위해서는 여러 가지 방법이 존재하나 본 연구에서는 각 입자 크기 노드별 개수 농도를 계산하였다. 노즐 출구에서의 가스 클러스터 크기를 예측하기 위하여 먼저, 노즐 내부 유속 및 온도 분포 변화를 해석하였다. 이를 통하여 온도가 급격하게 낮아져 생성된 클러스터의 효과적 가속 및 에너지 전달이 가능함을 확인할수 있었다. 이에 기반하여 GDE를 이용한 입자 크기를 예측한 결과 수 나노 크기의 초기 클러스터가 형성되어 온도가 낮아짐에 따라 성장하는 것을 확인할 수 있었으며, 최빈값의 분포가 실험적 측정값과 일치하는 경향을 가지는 것을 볼 수 있었다. 이는 향후 확장된 영역에서의 유동 해석과 증발 등 세부 요소를 고려한 계산을 통해 가스 클러스터 세정 공정의 최적화된 설계에 도움이 될 것이다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.9
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• pp.1511-1517
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• 2016

The aim of this study is to improve of properties for electrical AC insulation breakdown strength using epoxy/micro-nano alumina composites with adding glycerol diglycidyl ether (GDE:1,3,5g). This paper deals with the effects of GDE addition for epoxy/micro alumina contents (40,50,60wt%)+surface modified nano alumina(1_phr) composites. 14 kinds specimen were prepared with containing epoxy resins, epoxy micro composites and epoxy nano-micro alumina mixture composites. Average particle size of nano and micro alumina used were 30nm and $1{\sim}2{\mu}m$, respectively. The micro alumina used were alpha phase with Heterogeneous and nano alumina were gamma phase particles of spherical shape. The electrical AC insulation breakdown strength was evaluated by sphere to sphere electrode system and raising velocity 1kV/s. The AC breakdown strength decreased insulation properties of multi-composites according to increasing micro alumina and GDE addition contents.