• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2012년도 춘계학술논문요약집
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• pp.253-254
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• 2012

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2020년도 추계학술대회
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• pp.111-114
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• 2020

이 연구는 해운산업의 해운물류통합에 적용된 ICT기술들의 적용현황을 문헌연구를 통해 자료를 수집하고 정리하여 요약하여 conceptual model을 개발하고 전체적인 로드맵을 제시하였다.

• 공업화학
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• 제10권5호
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• pp.639-643
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• 1999

동시중합방법으로 에폭시수지와 castor oil형 폴리우레탄수지로 상호침투고분자(IPNs)를 형성하였다. 사슬연장제인 1,4-butanediol (BD)가 가교제인 BD/trimethylolpropane(TMP)에 따라 두 종류의 폴리우레탄(PU)을 제조했다. PU가 증가함에 따라, BD를 사슬연장제로 사용한 PU/epoxy가 BD/TMP를 가교제로 사용한 PU/epoxy SINs보다 damping피크의 이동이 컸다. BDPU/epoxy SINs는 BD/TMP-PU/epoxy SINs에 비해 사용성이 좋았다. 이러한 두 구조에서, 사슬연장제와 가교제에 따라 PU/epoxy SINs의 특이한 netwok 형성이 상혼합의 정도를 변화시켰음을 가정하였다. PU의 사슬연장제의 종류가 IPNs의 상혼합을 결정하는 중요한 인자였다. BD/TMP-PU의 반응이 에폭시수지의 가교반응보다 빠를 때, 가교구조의 entanglement가 감소하여 상혼합정도가 감소하였다. 두 PU/epoxy SINs는 굴곡특성과 파괴인성이 증가하였다. BDPU/epoxy SINs와 BD/TMP-PU/epoxy SINs의 파괴단면에서 PU의 공동화에 의한 응력백화현상과 전단변형을 보였다.

• 대한한의학회지
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• 제21권4호
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• pp.183-192
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• 2000

Objectives : The present study was carried out to investigate the effects of Danchun-hwan(DCH) on the peroxynitrite-induced neural cell death in human neuroblastoma cell line, SH-SY5Y. Methods : The cultured cells were pretreated with DCH and exposed to 3-morpholinosydnonimine(SIN-1) that simultaneously generates NO and superoxide, thus possibly forming peroxynitrite. The cell damage was assessed by using MTT assay and crystal violet staining. Results : Exposure of the cells to SIN-1 for 24hr induced 75% apoptotic cell death, as evaluated by the occurrence of morphological nuclear changes characteristic of apoptosis using 4', 6-diamidino-2-phenylinole(DAPI). However, pretreatment of SH-SY5Y with the water extracts of DCH, inhibited the apoptotic cell death in a dose-dependent manner. DCH also inhibited SIN-1-induced apoptotic caspase 3-like protease activity in a dose-dependent manner. DCH recovered the depleted glutathione levels by SIN-1. Conclusions : Taken together, it is suggested that DCH protected human neuroblastoma cell line, SH-SY5Y, from the free radical injury mediated by peroxynitrite by a mechanism of elevating antioxidant, GSH.

• 한국해양학회지
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• 제5권1호
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• pp.6-13
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• 1970

Ten days and monthly mean temperatures were analysed daily data observed during July, 1916 to March, 1970 statistically. Periodic characters were calculated by Δn, new method of approximate solution of Schuster Method. According to ten days mean temperatures, annual variation function is F($\theta_d$)=16.29-5.27 cos $\theta_d$+0.75 cos2 $\theta_d$-3.14 sin $\theta_d$+1.16 sin2 $\theta_d$-0.63 sin $\3{theta}_d$, where $\theta_d$=$-\frac{\pi}{18}$(d-3), d is the order of ten days period, 1 to 36. Annual mean water temperature is 16.3$^{\circ}C$, minimum in the last ten days of February 10.9$^{\circ}C$, maximum in the last ten days of August 24.5$^{\circ}C$. Periodic character of secular variation shows 11 year and its curve is F($\theta_y$)=16.29+0.53 cos $\theta_y$ -0.16cos $2{\theta}_y$+0.10 cos$3{\theta}_y$-0.10 sin $\theta_y$, where $\theta_y$=2$-\frac{2\pi}{11}$(y-1920), y is calendar year. And the relation between air temperature x and water temprature y is following. y=9.67 1.035$\^x$

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 C
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• pp.1694-1697
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• 2002

KEPCO is planing to adopt a preventive diagnostic system to obtain the reliability of transformer and GIS in 765kV substation. KEPRI has developed the preventive diagnostic system for 765kV substation since 1997. We used various sensors and fault detecting devices such as a dissolved gas analyzer in oil, a ultrasonic detector and LA leakage current detector, etc., and carried out adaptation tests at the both a laboratory and a site. We developed a data acquisition system, a communication control unit and a server system as well. Furthermore, monitoring program and diagnostic expert system were also developed. This paper describes the preventive diagnostic system for 765kV Sin-Ga-Pyong and Sin-Tae-Baek substations which will be operated from 2004.

• 한국자동차공학회논문집
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• 제10권6호
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• pp.150-157
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• 2002

In textured material, diffraction angle $2{\theta}$ usually shows a nonlinear relation against $sin^2{\psi}$ due to elastic anisotropy of crystals. SPHD and SPCD steel is cold-rolled carbon steel for automobile. The characteristics X-ray for stress measurement is Cr $K_{\alpha}\;and\;Mo\;K_{\alpha}$ characteristic X-ray. The $2{\theta}-sin^2{\psi}$ diagram under elastic strain seems to have a linear behavior using regression line of data but has a nonlinear behavior in distribution of data by Cr $K_{\alpha}$ characteristic X-ray. As the plastic strain of specimen increases, the nonlinearity of $2{\theta}$ with respect to $sin^2{\psi}$ increases remarkably. On the other hand, the diffraction angle $2{\theta}$ by Mo $K_{\alpha}$ characteristic X-ray shows a good linearity on $2{\theta}-sin^2{\psi}$ diagram under plastic strain as well as elastic strain. Therefore, this paper presents the measurement of residual stress in cold-rolled carbon steel for automobile using penetration depth of Mo $K_{\alpha1}$ characteristic X-ray and multiplicity factor of crystal diffraction plane.

• Journal of Electrical Engineering and Technology
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• 제9권4호
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• pp.1437-1445
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• 2014

In this paper a novel method for angular position determination using sensors with sin/cos output and without an excitation signal, is presented. The linearization of the sensor transfer characteristic and digitalization of the measurement results are performed simultaneously with a goal to increase the measurement resolution. This improvement is particularly important for low angular velocities, and can be used to increase the resolution of incremental Hall, magnetic and optical sensors. This method includes two phases of sin/cos signal linearization. In the first linearization phase the pseudo-linear signal is generated. The second linearization phase, executed by the two-stage piecewise linear ADC, is an additional linearization of the pseudo-linear signal. Based on the LabVIEW software simulations of the proposed method, the contribution of each processing phase to a final measurement error is examined. After the proposed method is applied within $2{\pi}$ [rad] range, the maximal nonlinearity is reduced from 0.3307 [rad] ($18.9447^{\circ}$) to $3{\cdot}10^{-4}$ [rad] ($0.0172^{\circ}$).

• 대한한방피부미용학회지
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• 제1권1호
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• pp.91-97
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• 2005

(1) Objectives: To discover natural skin-lightening agents, we have evaluated the inhibitory activity of EtOH extracts from 20 medicinal plants against mushroom tyrosinase. (2) Methods: Tyrosinase activity was determined by the dopachrome method using L-tyrosine as the substrates. (3) Results: Of the plant extracts tested, the extracts of 4 plants, Albizzia julibrissin, Curcuma longa, Anethum graveolens and Sophora flavescens, exhibited potent inhibitory activity (> 50%) in mushroom tyrosinase assay. Four plant extract, extracts of Agrimonia pilosa, Paeonia moutan, Magnolia obovata and Eugenia caryophyllata also showed relatively strong inhibitory (> 40%) against mushroom tyrosinase. (4) Conclusion: These active medicinal plants may be useful for the development of skin-whitening agents. Since the active medicinal plants may contain effective tyrosinase inhibitors even more than kojic acid, further study to identify the active constituents from the plants is expected.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1993년도 하계학술대회 논문집 B
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• pp.572-574
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• 1993

In order to obtain superior breakdown properties of Epoxy/$SiO_2$ composite materials at room and high temperature, the simultaneous interpenetrating polymer networks(SIN) is introduced into the Epoxy resin. As a result, it is observed that dielectric breakdown strength tends to increase according to the following order ; Epoxy/$SiO_2$ specimens, specimens treated with coupling agent and SIN introduced specimens which have stable temperature characteristics at room and high temperature. For introducing SIN Epoxy/$SiO_2$ composite material, rise of glass transition temperature and suppression of defects in its internal structure is achieved. This in turn improves the dielectric breakdown strength and the heat proof property of Epoxy/$SiO_2$ composite materials.