• Journal of the Korean institute of surface engineering
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• v.26 no.2
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• pp.71-81
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• 1993

Thed effects of Ar or Oxygen RF plasma treatment on the adhesion behavior of Cr films to polyimide sub-strates have been investigated by using SEM, XRD, AES, and $90^{\circ}$peel test. By applying RF plasma treatment of the polyimide surface prior to metal deposition, the peel adhesion strength of Cu/Cr films sputtered onto the fully cured BPDA-PDA polyimide was highly increased from about 3g/mm to 90 ~ 100g/mm. Improved peel adhesion strength of Cr/polyimide interfaces due to RF plasma treatment was attributed to the contributions from surface cleaning, Cr-polyimide bonding at the interface, and force required for plastic deformation of the film. While the surface topology change of the polyimide caused by RF plasma treatment makes a little contri-bution to the improved adhesion.

• Journal of Power Electronics
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• v.16 no.1
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• pp.374-387
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• 2016

This paper derives an improved analytical model to estimate switching loss and analyze the effects of parasitic elements on the switching performance of SiC MOSFETs. The proposed analytical model considers the parasitic inductances, the nonlinearity of the junction capacitances and the nonlinearity of the trans-conductance. The turn-on process and the turn-off process are illustrated in detail, and equivalent circuits are derived and solved for each switching transition. The proposed analytical model is more accurate and matches better with experimental results than other analytical models. Note that switching losses calculated based on experiments are imprecise, because the energy of the junction capacitances is not properly disposed. Finally, the proposed analytical model is utilized to account for the effects of parasitic elements on the switching performance of a SiC MOSFET, and the circuit design rules for high frequency circuits are given.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.05b
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• pp.34-37
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• 2004

It is well known that Ag-CdO alloy for electrical contactor has been widely used in weak or middle electric current field. But it is necessary to decrease Cd contents without decrease of contactor property because Cd is harmful to human body. The present work has been carried out to investigate effects of Mm (misch metal) addition on the property of Ag-CdO alloy for electrical contactor. As the results of present works, hardness and strength was improved and arc resistance was improved, also, in spite of decrease Cd contents by the Mm addition. It was estimated that Ag-oxide particle was refined by Mm addition.

• Journal of the Korean institute of surface engineering
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• v.30 no.2
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• pp.144-154
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• 1997

Effects of plasma nitriding on the surface charcteristice of stainless steel(SS) were investjgated by utilizing wear tester, micro-hardness tester and potentiostat. The surface and corrosion morphology of plasma nitrided SS were analyzed by utilizing optical microscopy, SEM, XRD and WDX. It was found that plasma nitriding at $550^{\circ}C$, compared with $380^{\circ}C$, prodiced a good wear resistance and hardness as nitriding time increased, whereas Mo addition showd that were resistance and hardness decreased. Intergranular corrosion(IGC) resistance improved significantly in the case of plasma nirtrided SS containing 4.05wt% Mo at $380^{\circ}C$ because that nitrogen and Mo ast syner gidically to form a protective layer on surface which is responsible for the aggresive SCN-ion. Plasma nitrided at $550^{\circ}C$ decreased IGC as Mo content increased. Pitting improved in the plasma nitirided SS at Mo content incresased owing to retard a nucleation and growth of chromium carbide or nitirde in grain boundary.

• Elastomers and Composites
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• v.39 no.4
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• pp.263-273
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• 2004

The effects of zinc surfactant (ZB) on the bis(triethoxysilylpropyl)disulfide (TESPD)-silica mixture in natural rubber (NR) and solution butadiene-co-styrene rubber(S-SBR) were compared with respect to their rheological property, processability, physical properties, and silica dispersion. In the NR compound, addition of the ZB increased the reversion resistance time (T-2), the tensile modulus, and the BO time; however, lowered the viscosity, the HBU, and tans values. In the S-SBR copound, addition of the ZB increased the $tan{\delta}$ values while lowered the T-2, the tensile modulus the BO time, the viscosity, and the HBU of the compound. In the NR compounds, addition of the ZB significantly increased the processability and mechanical property. However, in the S-SBR compounds, it improved the processability the mechanical property was not improved.

• Journal of International Academy of Physical Therapy Research
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• v.9 no.4
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• pp.1608-1613
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• 2018

The purpose of this study was to investigate the effects of sling exercise on muscle activity and balance on football players with chronic ankle instability. Eight subjects performed Biodex and sling exercises for four weeks and compared the muscle activity and balance ability of the uninjured and injured feet. Stable and unstable foot % MVIC did not change significantly after treatment in all muscles. The total balance ability was not significantly different between the two groups, however, increased only in the unstable side. The anterior/posterior balance ability also represented no significant difference between the groups and was significantly improved only in the unstable side. The medial/lateral balance ability was not significantly different between the groups and was significantly improved only in the unstable side. This study suggests that sling exercise contributes to improving % MVIC, total balance ability, anterior/posterior balance ability, and medial/lateral balance ability of the unstable side.

• Elastomers and Composites
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• v.57 no.2
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• pp.40-47
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• 2022

The effects of maleic-anhydride-grafted polypropylene (PP-g-MAH) and montmorillonite (MMT) on the wear resistance of polypropylene (PP) were investigated. The surface of MMT was modified with 3-aminopropyltriethoxysilane, and the interfacial interaction between PP and MMT was improved using PP-g-MAH. Fourier-transform infrared spectroscopy was used to confirm that silane was grafted on the surface of MMT. The Taber abrasion test and scanning electron microscopy were used to determine the wear resistance and observe the surface morphology of PP, respectively, after wear testing. Energy-dispersive X-ray spectroscopy was used to compare the effects of PP-g-MAH and silane modification of MMT on the dispersion of MMT. The results indicated that silane was successfully grafted onto the surface of MMT. Moreover, the wear resistance of PP was improved by the addition of MMT. The wear resistance of PP composites comprising silane-modified MMT and PP-g-MAH was higher than those of other PP composites. This was attributed to silane improving the interfacial interaction between MMT and PP.

• KDI Journal of Economic Policy
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• v.45 no.3
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• pp.1-24
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• 2023

This paper empirically examines the relationship between inter-Korean trade and inter-Korean relations over the past three decades. It asks two questions: (1) Does inter-Korean trade contribute to improved inter-Korean relations and peace on the Korean Peninsula? (2) Does improved inter-Korean relations lead to increased inter-Korean trade? The study employs a time-series causal relationship analysis methodology to answer these questions. The findings show that during the progressive government's reign, inter-Korean trade was not impacted by inter-Korean relations. This is due to the implementation of a political-economic separation policy towards North Korea. Moreover, the increase in general trade and processing on commission did enhance inter-Korean relations, reflecting the "inclusive policy" aimed at achieving peace on the Korean Peninsula through inter-Korean trade. In contrast, during the conservative government's reign, inter-Korean relations had a direct impact on inter-Korean trade, with deteriorating relations leading to a significant decrease in trade. This was due to the implementation of North Korea policies that were linked to politics and the economy.

• Journal of Communications and Networks
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• v.7 no.3
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• pp.278-283
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• 2005

This paper proposes a blind channel estimation scheme for long code direct sequence code division multiple access (DS­CDMA) systems with multipath fading channels. This scheme combines the advantages of Toeplitz displacement and correlation matching methods to achieve improved performance. The basic idea is to remove the effects of noise and interferences with Toeplitz displacement operation and then estimate the multi path channel parameters with the correlation matching method. Simulation results are presented to show that the proposed scheme provides better MSE performance and robustness against the near-far problem.

• Journal of the Korean Chemical Society
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• v.14 no.2
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• pp.179-184
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• 1970

Four-ball EP and wear testers were used to study the effects of thickeners and additives on the EP and wear properties of some Korean greases. The EP property improved in the order of Li < Al < Ca, and the concentration of thickener did not affect the property when the same base oil and additives were used. The anti-wear property was improved in general when the additives were used.