• Journal of the Korean Society for Heat Treatment
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• v.17 no.4
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• pp.236-240
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• 2004

Effect of plasma power on PECVD process were investigated in this study. TiN and TiCN films were deposited on nitrided STD11 steel with 600W, 1,200W and 1,600W plasma power. As the plasma power was increased, the preferred orientation was reinforced from (200) to (111) and the hardness of films was improved. The low plasma power was, however, effective for improving of adhesion force of films. Regarding above properties, TiN and TiCN films were deposited by gradient plasma power. It was possible to get high hardness as well as adhesion force through gradient plasma power.

• Communications for Statistical Applications and Methods
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• v.6 no.1
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• pp.267-274
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• 1999

We consider a doubly stochastically perturbed dynamical system {$X_n$} generated by $X_n\Gamma_n(X_{n-1})+W_n where \Gamma_n$ is a Markov chain of random functions and $W_n$ is i.i.d. random elements. Sufficient conditions for stationarity and geometric ergodicity of $X_n$ are obtained by considering asymptotic behaviours of the associated Markov chain. Ergodic theorem and functional central limit theorem are proved.

• Journal of the Chungcheong Mathematical Society
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• v.30 no.3
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• pp.337-340
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• 2017

In this article, we present characterizations of the power distribution via the identical hazard rate of lower record values that $X_n$ has the power distribution if and only if for some fixed n, $n{\geq}1$, the hazard rate $h_W$ of $W=X_{L(n+1)}/X_{L(n)}$ is the same as the hazard rate h of $X_n$ or the hazard rate $h_V$ of $V=X_{L(n+2)}/X_{L(n+1)}$.

• Journal of the Microelectronics and Packaging Society
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• v.25 no.3
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• pp.67-74
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• 2018

Thermoelectric thin film devices of the in-plane configuration consisting of 8 pairs of n-type $Bi_2Te_3$ and p-type $Sb_2Te_3$ legs were processed on Si submounts by electrodeposition. The thermoelectric generation characteristics of the thin film devices were investigated with respect to the apparent temperature difference ${\Delta}T$ caused by LED lighting as well as the change of the leg thickness. When ${\Delta}T$ was 7.4 K, the open circuit voltages of 6.1 mV, 7.4 mV, and 11.8 mV and the maximum output powers of 6.6 nW, 12.8 nW, and 41.9 nW were measured for the devices with the thermoelectric legs of which thickness were $2.5{\mu}m$, $5{\mu}m$, and $10{\mu}m$, respectively.

• Korean Journal of Materials Research
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• v.5 no.4
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• pp.445-450
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• 1995

AIN 완충층을 이용하여 대기압 유기금속에피텍셜 (MOVPE)법으로 사파이어 기판위에 성장시킨 AlGaN/GaN 이중 이종접합구조(double heterostructure : DH)의 고밀도 광여기에 의한 자외선 영역에서의 단면모드 유도방출 특성에 대하여 조사하였다. 실온에서 여기광 밀도 200kW/$cm^{2}$에서 방출된 AlGaN/GaN DH의 유도방출 피크파장과 반치폭은 각각 369nm와 22.4meV이었으며, 80K의 온도에서는 각각 360.1nm와 13.4meV이었다. 고밀도 광여기에 의하여 단면모드 자외영역 유도방출을 얻기에 필요한 입사광 밀도의 임계치는 실온과 80K의 온도에서 각각 89kW/$cm^{2}$와 44kW/$cm^{2}$이었다.

• Journal of the Korean institute of surface engineering
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• v.55 no.2
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• pp.77-83
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• 2022

Nanocrystalline MoN coatings were prepared by inductively coupled plasma magnetron sputtering (ICPMS) changing the plasma power from 0 W to 200 W. The properties of the coatings were analyzed by x-ray diffraction, field emission scanning electron microscopy, atomic force microscopy, nanoindentation tester and semiconductor characterization system. As the ICP power increases, the crystal structure of the MoN coatings changed from a mixed phase of γ-Mo₂N and α-Mo to a single phase γ-Mo₂N. MoN coatings deposited by ICPMS at 200 W showed the most compact microstructure with the highest nanoindentation hardness of 27.1 GPa. The electrical resistivity of the coatings decreased from 691.6 μΩ cm to 325.9 μΩ cm as the ICP power increased.

• Journal of Pharmaceutical Investigation
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• v.32 no.4
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• pp.291-297
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• 2002

For preventing and curing the stretching mark, TECA Niosome/W/O system creams were formulated using Titrated Extract of Centella Asiatica (TECA) which is well known for its excellent wound healing effect. The lipid-water partition coefficients and the stabilities of TECA were evaluated and TECA Niosome/W/O system (TECA N/W/O) creams were prepared with different concentrations of cetyl alcohol and ceramide. TECA N/W/O cream was evaluated with respect to their rheological properties, permeation through excised skin of hairless mouse and in vitro and in vivo accumulation in the skin of hairless mouse. In addition, dermal thicknesses of hairless mouse skins were determined following the in vivo application of TECA N/W/O cream and control cream. TECA N/W/O creams showed pseudoplastic flow and hysteresis loop. The permeation of TECA from formulations through excised skin of hairless mouse did not observed. Amount of accumulated drug in the excised skin of hairless mouse was deσeased with an increase in the concentration of cetyl alcohol and showed no relationship with concentration of ceramide. Amount of accumulated drug in formulation A-3 was higher than in niosome suspension and other formulations. In in vivo experiment, amount of accumulated drug in formulation A-2 and A-3 was much higher than that of niosome suspension. Being treated with the N/W/O cream for 8 weeks, the dermal thickness of hairless mouse skin was increased 3.2 times than that of 16 weeks-control group.

• Journal of Environmental Health Sciences
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• v.31 no.2 s.83
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• pp.160-164
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• 2005

This study was performed to evaluate the effects of washing food wastes before aerobic composting on temperature, pH and salinity, and the effects of washing after composting on salinity of sample mixtures. Weight ratios of food wastes to water in washing were 1:0(Control), 1:1(W-1), 1:2(W-2), 1:3(W-3) and 1:0(N-4), respectively. Ratios of food wastes to wood chips in reactor of Control, W-1, W-2, W-3 and N-1 were $5\;kg:0\iota,\;5\;kg:5\iota,\;5\;kg:5\iota,\;5\;kg:5\iota\;and\;5\;kg:5\iota$, respectively. Reactors were operated for 24 days with 1 hour stirring by 1 rpm and 2 hours of forced aeration per day. The increase in the ratio of water to food wastes resulted in the increase of the maximum reaction temperature and the shortening of the high temperature reaction period. The increase in the ratio of water to food wastes also resulted in faster reaching to the lowest pH and then to the steady state of pH 9.0. The final salinities of Control, N-1, W-1, W-2 and W-3 were $1.04\%,\;0.92\%,\;0.78\%,\;0.64\%\;and\;0.53\%$, respectively. The salinities of the N-l samples which were washed by the weight ratios (water:N-l) of 1:1, 2:1 and 3:1 after composting were $0.72\%,\;0.61\%\;and\;0.51\%$, respectively. Therefore, washing food wastes before aerobic composting is more efficient method than that after aerobic composting.

• Journal of the Korean Geotechnical Society
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• v.33 no.2
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• pp.5-15
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• 2017

PHC-W retaining wall method is one of the economical retaining wall methods. PHC-W pile used in PHC-W retaining wall method has special shape with flat surfaces so that the PHW-C retaining wall, with overlapped piles, shows outstanding vertical control and impermeability. In order to evaluate two types of retaining walls, numerical analysis were performed. The selection of cases depended on N values of the ground and ground properties, and two types of PHC-W retaining walls (defined as type A and B) were constructed. For a case that consists of inorganic clay and sand with less than 30 of N value, the maximum excavation depths for type A and B were respectively 10.5 m and 11.0 m. At the other case of which N value is above 30, the depths were 17.0 m and 19.5 m. From the results, it was found that maximum excavation depth, horizontal displacement, and safety factor for flexural strength of the wall were influenced by ground properties.

• Journal of IKEEE
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• v.26 no.1
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• pp.77-82
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• 2022

The effect of the bias network on the performance of the W-band power amplifier(PA) was investigated. The performances of the typical RC and radial stub networks were examined, and a hybrid network was proposed for W-band application and its performance was confirmed. To verify this, a W-band PA was designed using a 60-nm GaN pHEMT process. When hybrid networks were applied, the PA had improved stability in all frequency bands, secured about 9 dB of power gain at operating frequencies 87 GHz to 93 GHz, and the maximum PAE was found to be about 12.3% at output power of 26.7 dBm.