• ETRI Journal
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• 제23권4호
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• pp.199-201
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• 2001

The phase noise reduction in a configuration of the HEMT oscillator with a dielectric resonator coupled by a quarter-wavelength impedance inverter is investigated. Two HEMT oscillators for a satellite payload system are manufactured in the same configuration except for the coupling configuration of the dielectric resonator (DR) in order to empirically demonstrate the phase noise reduction. Experimental result shows that a phase noise reduction by 14 dB can be enhanced by increasing the characteristic impedance of a coupling microstrip impedance inverter.

• Journal of the Optical Society of Korea
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• 제2권1호
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• pp.30-33
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• 1998

We present the analysis of phase-shifted fiber Bragg gratings by coupled-mode equations. The transmission is expressed as that of a Fabry-Perot resonator with complex reflectance and complex transmittance. The transmission spectrum, the effective cavity length, and the behaviors with different phase-shifts are investigated. A very flattered transmission peak is obtained by introducing three phase-shifts in a grating.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 추계학술대회 논문집 학회본부 A
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• pp.139-141
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• 2000

High voltage direct current(HVDC) transmission system uses the phase controlled rectifier triggered by means of IPC(individual phase control) or EPC(equidistant pulse control). Most HVDC system has adopted EPC method that can solve the harmonic instability problem of IPC method in weak power system. But EPC has inherent indirect synchronizing problem requiring the closed loop control. This paper presents the new gate pulse generating method for 12-pulse HVDC converter, which combines IPC with EPC. Simulation and test results are presented. The basic concept is that it generates the gating pulse for 12-pulse converter by synthesizing the internal phase reference using the frequency and phase information of a sin91e phase voltage. To ensure the reliability of the external phase input, Potential transformer that detects the phase voltage has redundancy. Using fault detecting algorithm the healthy input is always guaranteed. And the frequency compensation function was reinforced.

• Biotechnology and Bioprocess Engineering:BBE
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• 제9권1호
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• pp.47-51
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• 2004

Ceramide III was prepared by the cultivation of Saccharomyces cerevisiae. Ceramide III was partitioned from the cell extracts by solvent extraction and analyzed by Normal Phase High Performance Liquid Chromatography (NP-HPLC) using Evaporative Light Scattering Detector (ELSD). We experimentally determined the mobile phase composition to separate ceramide III with NP-HPLC. Three binary mobile phases of n-hexane/ethanol, n-hexane/lsoprophyl Alcohol(IPA) and n-hexane/n-butanol and one ternary mobile phase of n-hexane/IPA/methanol were demonstrated. For the binary mobile phase of n-hexane/ethanol, the first mobile phase composition, 95/5(v/v), was step-increased to 72/23(v/v) at 3 min. In the binary mobile phase, the retention time of ceramide III was 7.87min, while it was 4.11 min respectively in the ternary system, where the mobile phase composition of n-hexane/IPA/methanol, 85/7/8(v/v/v), was step-increased to 75/10/15(v/v/v) at 3 min. However, in the ternary mobile phase, the more peak area of ceramide III was observed.

• Investigative Magnetic Resonance Imaging
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• 제19권3호
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• pp.200-204
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• 2015

Image findings of hepatic lymphoma have been reported as variable, ranging from single or multiple small nodules to diffuse infiltrative patterns. On MRI, most hepatic lymphomas show T1 low signal intensity, T2 high signal intensity. Dynamic imaging reveals a hypointense appearance in the arterial phase, followed by delayed enhancement in the portal venous and transitional phase. In the hepatobiliary phase using a hepatocyte-specific contrast agent (which have recently aided in increasing the access to the focal liver lesions), hepatic lymphoma is known to exhibit low signal intensity. We report a case of hepatic lymphoma, which shows iso-signal intensity on hepatobiliary phase, using gadoxetic acid (Gd-EOB-DTPA).

• 대한화장품학회지
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• 제39권2호
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• pp.83-88
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• 2013

수성 이상계는 물에 친수 성분만을 용해시킨 후 용해 물질들 사이에 유발되는 단순한 물리적 불친화성에 의해 액상 다중 층으로 분리되기 때문에 생체적합성에 대한 장점을 가지고 있다. 본 연구에서는 물에 친수 성분만을 용해시킨 후 두 층으로 분리되는 수성 이상계 상분리 원리를 수성 다중 층 액상 화장료에 응용하여 수성 다중 층 화장료에 적용이 가능한 대표적인 두 종의 수성 이상계를 선정하였으며, 이들에 대해 바이노달 곡선과 임계점 및 농도 대응선 그리고 새로운 개념의 상분리 부피 및 상분리 시간 대응곡선을 포함하는 상도를 실험을 통해 작성하였으며, 상 도표로부터 액상 다중 층으로 분리되는 최적의 조건을 관찰할 수 있었다.

• Macromolecular Research
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• 제15권7호
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• pp.656-661
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• 2007

The effects of a neutral solvent of dioctyl phthalate (DOP) on the phase behavior of symmetric polystyrene-block-poly(n-butyl methacrylate) copolymers (PS-b-PnBMA) were assessed herein. Closed-loop phase behavior with a lower disorder-to-order transition (LDOT) and an upper order-to-disorder transition (UODT) was observed for PS-b-PnBMA/DOP solution when the quantity of DOP was carefully controlled. When the molecular weight of PS-b-PnBMA became larger, the LDOT did not appreciably change at smaller quantities of DOP. With larger quantities of DOP, the reduction in the UODT is greater than the increase in the LDOT. This behavior is discussed in accordance with a molecular theory predicated on a compressible random-phase approximation.

• 한국표면공학회지
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• 제40권2호
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• pp.91-97
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• 2007

In this study we investigated the oxygen effect on the nucleation and its residual stress during unbalanced magnetron sputtering. Up to 0.5% in oxygen flow rate, cubic phase (c-BN) was dominated with extremely small fraction of Hexagonal phase (h-BN) of increasing trend with oxygen concentration, whereas hexagonal phase is dominated beyond 0.75% flow rate. Interestingly, the residual stress in cubic-phase-dominated films was substantially reduced with small amount of oxygen (${\sim}0.5%$) down to a low value comparable to the h-BN case. This may be because oxygen atoms break B-N $sp^3$ bonds and make B-O bonds more favorably, increasing $sp^2$ bonds preference, as revealed by FTIR and NEXAFS. It was confirmed by experimental facts that the threshold bias voltage for nucleation and growth of cubic phase were increased from -55 V to -70 V and from -50 V to -60 V respectively. The reduction of residual stress in O-added c-BN films is seemingly resulting from the microstructure of the films. The oxygen tends to increase slightly the amount of h-BN phase in the grain boundary of c-BN and the soft h-BN phase of 3D network including surrounding nano grains of cubic phase may relax the residual stress of cubic phase.

• Korean Journal of Acupuncture
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• 제39권2호
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• pp.63-67
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• 2022

Objectives : The purpose of this study was to investigate the needling depth of five-phase acupoints and discuss the association with the depth of meridian qi. Methods : DongUiBoGam was used to determine the depth of five-phase acupoints. The depth of needling at 60 five-phase acupoints was compared between well, spring, stream, river, and sea acupoints. Results : The proximal part of the extremities had deeper needling depth than the distal part of the extremities. The targeted deqi sensation can be related to the needling depth. Conclusions : The depth of the meridian qi is related to the distinct patterns of needling depth of five-phase acupoints.

• Bulletin of the Korean Chemical Society
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• 제29권10호
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• pp.1941-1945
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• 2008

A new chromatographic stationary phase has been prepared by cross polymerization between allylsilica and perallyloxycucurbit[6]uril and characterized by elemental analysis and FT-IR spectroscopy. The double endcapping has been proven to improve the separation efficiency of the cucurbituril-based stationary phase material. The first end-capping was carried out when allylsilica was made. The second end-capping was done as the final step of the whole process, and the use of a mixture of hexamethyldisilazane (HMDS) and trimethylchlorosilane (TMCS) as an end-capping reagent was found better than the use of only HMDS or TMCS. Our stationary phase has shown generally good results in separation of nonpolar and polar analytes. This phase showed even better separation performance than the commercial C18 phase for the case where hostguest chemistry was properly incorporated in solute retention.