• Korean journal of food and cookery science
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• 제17권1호
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• pp.55-59
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• 2001

To investigate the usefulness of Allium senescens as a aromatic edible plant, volatile flavor components and flavor pattern were analyzed. Essential oils of fresh and freeze dried Allium senescens were extracted by SDE(simultaneous steam distillation and extraction) method using diethyl ether as solvent. And their volatile flavor components were analyzed by gas chromatography(GC) and gas chromatography-mass spectrometry (GC-MS). A total of 46 components, including 11 hydrocarbons, 9 aldehydes, 4 alcohols, 2 esters, 7 acids, 4 ketones and 9 sulfur containing compounds were identified in fresh Allium senescens. In freeze dried Allium senescens, 8 hydrocarbons, 5 aldehydes, 3 alcohols, 5 esters, 2 acids, 3 ketones and 4 sulfur containing compounds were identified. Volatile flavor patterns of Chinese chive and Allium senescens were compared using electronic nose. The score of first principal component was significantly different in Allium senescens and Chinese chive.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제31권2호
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• pp.102-106
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• 2018

Recently, there has been an increasing interest in the use of graphene as electrode materials for supercapacitors. In this regard, graphene oxide (GO) films were prepared using GO slurry obtained by dispersing GO powder in deionized (DI) water. The degree of dispersion of GO powder in DI water depends on the concentration of GO slurry, pH, impurity content, GO particle size, types of functional groups contained in GO, and manufacturing method of GO powder. In this study, the dispersivity of the GO powder was improved by adjusting the pH using only DI water (without additives), and a uniform GO film was obtained. The GO film was reduced by exposure to xenon intense pulsed light for a few milliseconds, and the reduced GO film was used as electrodes of a supercapacitor. The supercapacitor was characterized using cyclic voltammetry (CV), charge-discharge cycle, and electrochemical impedance spectroscopy measurements, and the specific capacitance of the supercapacitor was found to be ~140 F/g from the CV data.

• Korean journal of food and cookery science
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• 제14권5호
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• pp.547-552
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• 1998

Essential oils in leaf of fresh Aster glehni were extracted by SDE (simultaneous steam distillation and extraction) method using diethyl ether as solvent. The yield of the essential oils was 0.05%. And their volatile flavor components were analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC-MS) and identified by the RI of GC and mass spectrum of GC-MS. A total of 31 components, including 17 hydrocarbons, 2 aldehydes, 7 alcohols, 3 esters, 1 acid and 1 oxide were identified. The major volatile flavor components of fresh Aster glehni were ${\alpha}$-pinene, limonene, $\delta$-elemene, ${\beta}$-pinene, cis-3-hexenol and myrcene. Volatile flavor patterns of fresh ind dried Aster glehni were analyzed using an electronic nose. Sensor PA2 that was sensitive to alcohols showed the highest resistance for fresh and dried Aster glehni. Resistance of six metal oxide sensors was decreased in fresh sample compared with dried one.

• The KIPS Transactions:PartD
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• 제10D권1호
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• pp.67-76
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• 2003

The reuse of software is to use the components of software to be made beforehand to improve the productivity of it. The development of electronic commerce requires it which can be shown from changing the change of business models Reuse is the necessary solution to cope with a rapid change in the electronic commercial transaction. These reuse business models have the defects that they are not offered from version management. This paper has the purpose that by doing the supplementation of defects not to be offered from the version management and by introducing the quick change management about reuse business models, reusing the components and saving a development and reducing a development af period. The reuse of components by the new reuse business models has the advantages to minimize the danger elements from the design to the finish. We use the version management and try to present the method to make the efficiency of reuse by introducing components and managing the elements about components to the version in the technique to accomplish the reuse of software.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2003년도 추계학술대회 논문집 Vol.16
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• pp.36-41
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• 2003

This paper presents the results of power spectra using the fundamental and low frequency harmonic components of leakage current waveform to study aging on contaminated EPDM insulator(was serviced during 1997-2001, region Pohang, korea) under salt fog conditions. Experiments have been conducted in the chamber salt fog and at the 16KVrms. The salt contents adjusted as 0g,25g,50g and 75g per liter of deionized water. The onset of dry-band arcing on polymer insulators could be determined by signal processing the low frequency harmonics components. A correlation has been found between the fundamental and low harmonic components of power spectra on leakage current. Where aging could be associated with an increase in the level of both the fundamental and low frequency harmonics components of leakage current. Surface aging for contaminated EPDM insulators occurred when the fundamental component of leakage current was greater then some level On the other hand, when the polymer insulator approached failure, the fundamental component of leakage current reached relatively high values and low frequency harmonics components of the leakage current trended to decrease. The results suggest that both the fundamental and low frequency harmonics of leakage current can be used as a tool to determine both the beginning of aging and before flashover, end of life EPBM insulator in salt fog.

• The Journal of Natural Sciences
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• 제17권1호
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• pp.31-37
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• 2006

We have found that the polarization mode coupling between the orthogonally linearly polarized dual mode laser results from the anisotropy of dipole moments. Rate equation analysis demonstrated that high anisotropy in dipole moment components can give rise to law intrinsic mode coupling constants while isotropic dipole moment components give high intrinsic mode coupling constant. The populations at active ion sites are shown to self-organize the populations such that laser mode gain is constant adove threshold while the gain contributions from the each site adjust themselves with pump power.

• Proceedings of the KIPE Conference
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.417-418
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• 2016

일반적인 상용차에서 사용되고 있는 기계식 에어컨 시스템은 엔진의 가동(주행 또는 공회전)에 의해 발생되는 에너지를 이용해 차량 실내온도를 유지시켜준다. 이러한 기계식 에어컨 시스템의 작동은 엔진 구동력의 일부를 사용하기 때문에 상용차의 연비와 큰 관련성 있다. 상용차량은 경우 하절기 작업대기, 차량 내 야간취침 등이 빈번해 운전자의 운행습관에 따라 연료 소비량이 증가하는 단점을 가지고 있다. 본 논문에서는 이러한 단점을 개선하고자 대형 상용차량이 정차중인 무시동 기간에도 일정 온도의 유지가 가능한 전동식 압축기 구동용 Cascaded Push-Pull 컨버터를 제안하였다.

• Proceedings of the KIEE Conference
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• 대한전기학회 1996년도 하계학술대회 논문집 A
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• pp.355-357
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• 1996

With the wide-spread use of rectifier in electronic equipments, such problems as electronic components failures or equipment disorders have been occurred due to current harmonics. To overcome these problems, power factor correction circuits employing boost converter have been used. The switching stress of boost converter can be reduced by snubber circuit. Recently, research activities in snubber circuits have been directed to energy recovery snubber for improving the efficiency of power converter. In this study, a new passive snubber circuit which can recover trapped snubber energy without added control is proposed for boost converter The control of boost converter with proposed snubber is the same as the conventional one. In addition, the energy recovery circuit can be implemented with a few passive components. The circuit operation is confirmed through simulation.

• Journal of the Korean Graphic Arts Communication Society
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• 제28권1호
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• pp.1-13
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• 2010

Gravure printing and manufacturing of advanced electronic components in a way that is going extra hold position. It is to print the electronic components of the rapid productivity improvements as well as cost-saving and environment-friendly industries such as the transition is a big advantage. However the mechanism of gravure is difficult to study scientifically because of high speed and excessively small size of the cell. To approach the mechanism we experimented using gravure printability. The condition of variables of IGT is pressure and velocity. By using Flow-3D simulation software, we built up the theoretical model under the constant variables. Then, we compared the real test with the simulation results. Therefore, it is studied the mechanism of gravure scientifically and it can be analysed the effect of the variable conditions.

• The Transactions of the Korean Institute of Electrical Engineers P
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• 제60권2호
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• pp.94-98
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• 2011

Electrolytic power capacitors today form essential components for virtually any power electronic system such as DC/DC converter or UPS. Frequently, electrolytic capacitors for DC link voltage smoothing are the key components which determine the life cycle of the whole unit and often are responsible for converter breakdown failures. In this paper, ethernet-based remote diagnosis system for DC voltage smoothing capacitor using DSP control board is developed. To estimate the status of the capacitor, the equivalent series resistor(ESR) of the component has to be determined. The ESR detection scheme is based on the determination of the capacitor ripple power losses calculated from DC link voltage/current measurement. Experimental results show the veridity and reliability of the proposed ethernet-based remote on-line capacitor diagnosis system.