• 한국초전도학회:학술대회논문집
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• v.9
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• pp.196-199
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• 1999

The coexistence of the superconductivity and magnetism in the Ho1-xDyxNi2B2C is studied by using Ginzburg-Landau theory. This material violates the standard do Gennes scaling showing the coexistence and complex interplay of superconducting and magnetic order yielding an anomalous phase diagram. We propose a phenomenological model which includes two magnetic and two superconducting order parameters accounting for the multi-band structure of this material. We describe the magnetic fluctuations and order and demonstrate that they lead to anomalous behavior of the upper critical field. The doping dependence of Tc in Ho1-xDyxNi2B2C showing a reentrance behavior are analyzed yielding a very good agreement with experimental data.

• Journal of Microbiology and Biotechnology
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• v.30 no.5
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• pp.749-752
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• 2020

In the search for novel, natural melanogenesis inhibitors, a new sesquiterpene, inularin, was isolated from the flowers of Inula britannica, and the structure was determined using spectroscopic and chemical methods. The antimelanogenic effects of inularin on B16F10 melanoma cells and zebrafish embryos were evaluated. Inularin dose-dependently reduced melanocyte-stimulating hormone-induced melanin production and L-DOPA oxidation in B16F10 cells. Zebrafish embryos were used to confirm the antimelanogenic activity. Inularin significantly decreased the pigmentation of embryos compared with untreated controls.

• Progress in Superconductivity
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• v.12 no.1
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• pp.36-40
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• 2010

We have studied the anisotropy of the London penetration depth of carbon doped $MgB_2$ single crystals, which was obtained from reversible magnetization measurements with the magnetic field both parallel and perpendicular to the c-axis. Similar to the pure $MgB_2$, the anisotropy of the upper critical field ${\gamma}_H$ decrease with temperature while the anisotropy of the London penetration depth ${\gamma}_{\lambda}$ slowly increases with temperature. However, the temperature dependence of ${\gamma}_H$ is drastically reduced and the value of ${\gamma}_{\lambda}$ becomes nearly ~1 as C is introduced. These results indicate that C substitution increases impurity scattering mainly in the $\sigma$ bands. The temperature dependence of the anisotropies agree well with the theoretical predictions with impurity scattering.

• Proceedings of the Korean Biophysical Society Conference
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• 1996.07a
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• pp.43-43
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• 1996

Bovine angiogenin (bAng) is a potent blood vessel inducing protein purified from cow milk. Fluorescence spectroscopy has been used to study the interaction of bAng with actin in 50 mM Tris-HCl, pH 7.5, and 1 mM CaCl$_2$ at 25$^{\circ}C$. Actin contains four tryptophans but bAng contains no tryptophans. A 50% decrease in intrinsic fluorescence accompanied formation of the bAng/actin complex. (omitted)

• Proceedings of the IEEK Conference
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• 2006.06a
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• pp.993-994
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• 2006

현대 Mobile module에 알맞은 IP들은 고속에서 얼마나 소비 전력을 낮춰주느냐 하는 방향으로 진화하고 있다. 본 논문에서는 저전력 구현을 위해 digital block에서의 신호를 제어해주는 방법을 사용한 UWB system용 6B 2.5Gsample/s Flash ADC를 소개한다. 소개된 ADC는 2.5GS/s의 clock, 1240MHz의 input 신호에서 36,7dB의 SNDR과 5.80 비트의 ENOB를 가지며 385mW의 전력을 소모한다.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.523-524
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• 2006

The $TiB_2$ dispersion strengthened copper alloy was attracted as thermal and electrical functional material for the high mechanical strength, high thermal stability and good conductivity of $TiB_2$. In the present study, the focus is on the synthesis of $TiB_2$ dispersed copper alloy by spark plasma sintering process using copper oxide and titanium diboride as raw materials. The mechanical, thermal and electrical properties of sintered bodies were discussed with the sintering parameters, and developed microstructure and phase of sintered bodies.

• Journal of Powder Materials
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• v.14 no.5
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• pp.292-297
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• 2007

The present study was focused on the synthesis of a $TiB_2$ dispersed copper matrix composite material by the combination of the mechanical milling and plasma activated sintering processes. The $Cu/TiB_2$ mixed powder was prepared by the combination of the mechanical milling and reduction processes using the copper oxide and titanium diboride powder as the raw material. The synthesized $Cu/TiB_2$ mixed powder was sintered by the plasma activated sintering process. The hardness and electric conductivity of the sintered bodies were measured using micro vickers hardness and four probe method, respectively. The relative density of $Cu/TiB_2$ composite material sintered at $800^{\circ}C$ showed about 98% of theoretical density. The $Cu-1vol%TiB_2$ composite material has a hardness of about 130Hv and an electric conductivity of about 85% IACS. The hardness and electric conductivity of $Cu-3vol%TiB_2$ composite material were about 140 Hv and about 45% IACS, respectively.

• Elastomers and Composites
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• v.33 no.1
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• pp.27-36
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• 1998

The surface of wiper blade(W/B) rubber was chlorinated by chemical treatment method using the hydrochloric acid(HCI) and sodium hypochlorite(NaOCl). From the results of contact angle measurement, friction coefficient measurement, and ATR-IR spectra, the surface characteristics of chlorinated W/B rubber with time of chlorination were studied. Contact angles for W/B rubber with increasing time of chlorination and chlorine concentration were measured for the water and ethylene glycol. From the results, contact angle fell rapidly with increasing time of chlorination and chlorine concentration, reaching a constant value after about 10min. And the wettability of W/B rubber surface by means of chlorination has been improved. For an unchlorinated W/B rubber, the friction coefficient with time of chlorination decreased from 1.27 to 0.20~0.23 on full chlorination. As the results it was considered that abrasion resistance of W/B rubber surface has been also improved. The values of pH and $Cl^-$ ion concentration in a chlorine treatment solution decreased as the extent of chlorination of W/B rubber surface increased. From the results of ATR-IR spectra, it was observed that C=C double band of W/B rubber surface transformed into C-Cl band, but quantitative determination of the extent of chlorination was not feasible because of the complexity of chlorination reactions.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.2073-2075
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• 2004

본 논문에서는 nonradiative dielcctric (NRD) 도파로를 이용하여 28GHz대에서의 single balanced mixer를 설계하였다. 혼합기에 필요한 $90^{\circ}$ hybrid direction기 3dB 결합기를 NRD 도파로를 이용하여 설계 하였고 CST MWS를 이용하여 설계 결과를 검중 하였으며 결과는 중심 주파수 28GHz에서 대역폭이 1GHz의 결합기를 설계하였음을 확인할 수 있었다. 이와동시에 다이오드를 부착하기 위해 NRD 도파로와 마이크로스트립의 매칭 구조를 1 pole UDR과 patch를 이용하여 혼합기를 설계, 제작하였다.

• Proceedings of the KIEE Conference
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• 1996.07a
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• pp.127-129
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• 1996

A 3-dimensional analysis is desired for a magnet of magnetically levitated vehicle because the geometrical shape of the magnet is complicated and nonsymmetric. A FEM package of FLUX3D is used to analyze the characteristic of the magnet. Various quantities could be observed like levitation force, flux density distribution along the air gap, edge and fringing effect, leakage flux pattern, etc. The simulation results from FLUX3D are compared with those of 2-D analysis and test results. There are a little difference between results due to the boundary conditions and magnetized B-H curve of the core.