• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-2
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• pp.186.4-187
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• 2003

Acanthoside-D, one of major components of Acanthopanacis Cortex, is known as a ginseng-like substance. it has been known to possess diverse biological effects. Acanthoside-D has a furofuran lignan structure and the synthesis of which poses interesting and often unsolved proplems of stereocontrol. Although a few interesting syntheses providing this natural product have been reported, an intermolecular McMurry coupling - intramolecular Mitsunobu cyclization route has not yet been explored. We report here a short and efficient synthetic pathway to the total synthesis of Acanthoside-D from aryl aldehydes and methyl acrylates via Baylis-Hillman reaction, intermolecular McMurry coupling and intramolecular Mitsunobu cyclization as key reaction.

• 한국정보통신학회논문지
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• 제22권7호
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• pp.1015-1020
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• 2018

공동공진기는 마이크로파 응용에서 많이 사용되는 부품 중의 하나이다. 무부하 Q, 공진주파수, 그리고 결합계수는 공진기 기본 파라미터이다. 손실결합이 있는 공동공진기의 무부하 Q를 측정하는 간편한 절차를 제안하였다. 공진주파수 근처 주파수 대역에서 결합손실을 포함한 등가회로를 보였으며, 결합손실은 공진기의 임피던스를 측정하여 구했다. 결합손실을 보상한 공진기의 임피던스를 스미스차트에 다시 그렸다. 보상한 임피던스 궤적에서 부하 Q와 결합계수를 구하여 무부하 Q를 계산하였다. 제안한 절차를 검증하기 위하여 결합 손실이 없는 공진기를 측정하였다. 결합 손실이 있는 경우와 손실이 없는 경우의 측정결과는 잘 일치 하였다. 측정된 결과는 제안한 절차가 유용함을 확인하였다.

• Bulletin of the Korean Chemical Society
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• 제32권spc8호
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• pp.3120-3122
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• 2011

• 한국정보과학회논문지:소프트웨어및응용
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• 제33권3호
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• pp.301-315
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• 2006

컴포넌트 기반 시스템에서 재사용 단위인 컴포넌트의 품질은 시스템 개발의 성공을 위해서 가장 중요하다. 컴포넌트의 품질을 향상시키기 위해서는 개발 이전에 측정 가능해야 하고, 그 결과를 컴포넌트 개발 과정에 반영할 수 있어야 한다. 또한 컴포넌트의 품질을 정확하게 측정하여야 한다. 따라서 본 논문에서는 클래스들 간의 상호작용에 의한 정적 그리고 동적인 특성을 적용하여 식별된 컴포넌트의 품질을 좀 더 정확하게 측정할 수 있는 컴포넌트의 응집도와 결합도 메트릭스를 제안한다. 제안된 메트릭스가 이론적으로 타당하다는 것을 검증하기 위하여 Briand이 정의한 프레임워크에 적용하여 증명한다. 또한 메트릭스의 실용성을 검증하기 위해서 사례를 제시하고 기존의 메트릭스와의 비교분석을 통해서 평가 결과를 제시한다. 본 논문에서 제안한 컴포넌트 메트릭스는 식별된 컴포넌트의 품질을 좀 더 정확하게 측정함으로써 컴포넌트 설계를 위한 개발 시간과 노력을 절감한다.

• 전기학회논문지
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• 제57권6호
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• pp.938-943
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• 2008

Coupling capacitor voltage transformers(CCVTs) have been used in extra or ultra high voltage systems to obtain the standard low voltage signal for protection and measurement. For fast suppression of the phenomenon of ferroresonance, three winding CCVTs are used instead of two winding CCVTs. A tuning reactor is connected between a capacitor voltage divider and a voltage transformer to reduce the phase angle difference between the primary and secondary voltages in the steady state. Slight distortion of the secondary voltage is generated when no fault occurs. However, when a fault occurs, the secondary voltage of the CCVT has significant errors due to the transient components such as dc offset component and/or high frequency components resulting from the fault. This paper proposes an algorithm for compensating the secondary voltage of a three winding CCVT in the time domain. With the values of the measured secondary voltage of the three winding CCVT, the secondary, tertiary and primary currents and voltages are estimated; then the voltages across the capacitor and the tuning reactor are calculated and then added to the measured voltage. Test results indicate that the algorithm can successfully compensate the distorted secondary voltage of the three winding CCVT irrespective of the fault distance, the fault impedance and the fault inception angle as well as in the steady state.

• 전력전자학회논문지
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• 제20권3호
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• pp.262-272
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• 2015

An integrated two-in-one transformer applicable to PSUs for a 120 W LED TV is proposed. This transformer comprises a PFC inductor and an LLC transformer placed and integrated on an E-I-E type magnetic core. Performance is evaluated by observing the coupling coefficients of the proposed two-in-one transformer under various air gap topologies. Among the topologies studied, an integrated transformer with centered air gap shows stable operational characteristics with a minimized mutual coupling (interference). Furthermore, applicability of the proposed integrated transformer to PSUs for a 120 W LED TV is studied from the viewpoint of integrating different magnetic components into one core, resulting to low weight, low cost, and high power density.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2000년도 춘계종합학술대회
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• pp.205-209
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• 2000

현재의 무선통신기기는 다양한 멀티미디어의 제공과 함께 저전력, 소형·경량화, 단말기 가격의 저렴화가 개발의 목표가 되고 있다. 그러나, 기존의 무선통신시스템인 헤테로다윈 방식으로는 사용부품의 다양성 때문에 소형·경량화 및 부품의 On-Chip 작업에 어려움이 있어 미래형무선통신의 시스템으로는 적합하지 못하다. 이에 현재 연구개발이 진행되고 있는 방식 직접변환(Direct-Conversion)방식이다. 직접변환방식은 무선주파수 대역을 바로 기저대역을 하향변환 하므로써, 부가적인 부품의 사용과 소비전력의 감소에 상당한 이점이 있다. 이에 직접변환방식에 대한 이론적 설명과 함께 현재 무선통신 시스템으로 사용하기 위해 해결해야될 과제인 DC-Offset의 설명과 그 제거방법중의 하나인 AC-Coupling 기법의 시스템 적용으로 인한 시스템의 성능향상을 예측하고자한다

• 한국초전도ㆍ저온공학회논문지
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• 제18권1호
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• pp.41-45
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• 2016

The technology of supplying the electric power by wireless power transfer (WPT) is expected for the next generation power feeding system since it can supply the power to portable devices without any connectors through large air gap. As such a technology based on strongly coupled electromagnetic resonators is possible to deliver the large power and recharge them seamlessly; it has been considered as a noble option to wireless power charging system in the various power applications. Recently, various HTS wires have now been manufactured for demonstrations of transmission cables, motors, MAGLEV, and other electrical power components. However, since the HTS magnets have a lower index n value intrinsically, they are required to be charged from external power system through leads or internal power system. The portable area is limited as well as the cryogen system is bulkier. Thus, we proposed a novel design of wireless power charging system for superconducting HTS magnet (WPC4SM) based on resonance coupling method. As the novel system makes possible a wireless power charging using copper resonance coupled coils, it enables to portable charging conveniently in the superconducting applications. This paper presented the conceptual design and operating characteristics of WPC4SM using different shapes' copper resonance coil. The proposed system consists of four components; RF generator of 370 kHz, copper resonance coupling coils, impedance matching (IM) subsystem and HTS magnet including rectifier system.

• Fibers and Polymers
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• 제2권3호
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• pp.159-163
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• 2001

Five yellow disperse dyes were synthesized and their dyeing, fastness and photodegradation behaviors were investigated. It was found that dyes derived from phenylindole and N-alkylaminobenzene showed dye uptake directly proportional to the dye concentration, but the build-up of dyes derived from carbazole and pyridone were not good. The wavelength at maximum absorption. molar extinction coefficient. and the tendency to the photodegradation were strongly dependent on the electron donating ability of the coupling component. The dye, whose coupling component was phenylindole, possessed the excellent dyeing properties and the high degree of lightfastness. UVA had an effect on the inhibition of the photodegradation especially for the easily photodegradabte dyes.

• 한국전기전자재료학회논문지
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• 제17권1호
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• pp.16-20
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• 2004

We present the fabrication and performance of wavelength tunable butt coupled (BT) sampled-grating (SG) distributed bragg reflector (DBR) - planar buried heterostructure (PBH) laser diodes (LD). The fabricated LD showed the high optical output power due to the high coupling efficiency between active and passive components by the BT coupling methods. The series resistance and diode ideality factor of LD were measured to be 3.7 $\Omega$ and 1.35, respectively. The average threshold current was 25 ㎃. The output powers of BT-SG DBR-PBH-LD were obtained to be as high as 12.3 and 24.56 ㎽ at 100 and 200 ㎃, respectively. The maximum wavelength tuning range was about 31 nm and the side mode suppression ratio was about 37 dB.