• 전기학회논문지
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• 제58권8호
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• pp.1504-1511
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• 2009

By development of renewable energies and high-efficient facilities and deregulated electricity market, the operation cost of distributed generation(DG) becomes more competitive. The amount of distributed resource is considerably increasing in the distribution network consequently. Also, international environmental regulations of the leaking carbon become effective to keep pace with the global efforts for low-carbon paradigm. It contributes to spread out the business of DG. Therefore, the operator of DG is able to supply electric power to customers who are connected directly to DG as well as loads that are connected to entire network. In this situation, community energy system(CES) having DGs is recently a new participant in the energy market. DG's purchase price from the market is different from the DG's sales price to the market due to the transmission service charges and etc. Therefore, CES who owns DGs has to control the produced electric power per hourly period in order to maximize the profit. If there is no regulation for carbon emission(CE), the generators which get higher production than generation cost will hold a prominent position in a competitive price. However, considering the international environment regulation, CE newly will be an important element to decide the marginal cost of generators as well as the classified fuel unit cost and unit's efficiency. This paper will introduce the optimal operation of CES's DG connected to the distribution network considering CE. The purpose of optimization is to maximize the profit of CES and Particle Swarm Optimization (PSO) will be used to solve this problem. The optimal operation of DG represented in this paper is to be resource to CES and system operator for determining the decision making criteria.

• 대한전자공학회논문지
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• 제26권5호
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• pp.46-51
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• 1989

DC 스트레스에 의해 노쇠화된 짧은 채널 LDD NMOSFET에서 문턱전압과 subthreshold 전류곡선의 변화를 관측하여 hot-carrier 주입에 의한 노쇠화를 연구하였다. 포화영역에서 정의된 문턱전압의 변화 ${Delta}V_{tex}$를 trapped charge에 기인한 변화성분 ${Delta}V_{ot}$와 midgap에서 문턱전압 영역에 생성된 계면상태에 의한 변화성분${Delta}V_{it}$로 분리하였다. 게이트 전압이 드레인 전압보다 큰 positive oxid field ($V_g>V_d$) 조건에서는 전자들이 게이트 산화막으로 주입되어 문턱전압이 증가되었으나 subthreshold swing은 크게 변화하지 않고 subthreshold 전류곡선만 높은 게이트 전압으로 평행 이동하였다. 게이트 전압이 드레인 전압보다 낮은 negative oxide field ($V_g) 조건에서는 hole이 주입되고 포획된 결과를 보였으나 포획된 positive charge수 보다 더 많은 계면상태가 동시에 생성되어 문턱전압과 subth-reshold swing이 증가되었다.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.396-399
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• 2002

Intense quasi-monochromatic x-ray irradiation from the linear plasma target is described. The plasma x-ray generator employs a high-voltage power supply, a low-impedance coaxial transmission line, a high-voltage condenser with a capacity of about 200 nF, a turbo-molecular pump, a thyristor pulse generator as a trigger device, and a flash x-ray tube. The high-voltage main condenser is charged up to 55 kV by the power supply, and the electric charges in the condenser are discharged to the tube after triggering the cathode electrode. The x-ray tube is of a demountable triode that is connected to the turbo molecular pump with a pressure of approximately 1 mPa. As electron flows from the cathode electrode are roughly converged to the molybdenum target by the electric field in the tube, the weakly ionized plasma, which consists of metal ions and electrons, forms by the target evaporating. In the present work, the peak tube voltage was almost equal to the initial charging voltage of the main condenser, and the peak current was about 20 kA with a charging voltage of 55 kV. When the charging voltage was increased, the linear plasma x-ray source grew, and the characteristic x-ray intensities of K-series lines increased. The quite sharp lines such as hard x-ray lasers were clearly observed. The quasi-monochromatic radiography was performed by a new film-less computed radiography system.

• 한국정보통신학회논문지
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• 제13권6호
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• pp.1157-1166
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• 2009

경락선상에서 침을 이용한 침술효과가 서양과학에 의해 현재까지 증명되지 않고 있다. 본 연구에서는 일반 수기침술에 의한 전기적 해석에 근거하여 수기자침을 사용하지 않고 전자기장 자극을 통한 경락전위변화를 측정함으로써 통증치료에 유의한 자극 시스템을 개발하였다. 특히 전자계를 발생시키고 집중시키기 위해서 전극 코어의 자성체에 코일을 감아 인가전류에 따른 자속밀도(강도)를 다양하게 발생시킬수 있도록 설계하였다. 자극모드도 다양하게 선택할수 있어서 다양한 치료효과를 기대할수 있도록 하였다. 유의성 평가를 위해 족양명위경상의 상거허혈과 하거허혈에 전극을 부착하고, 족삼리에 전자기자극을 하여 두 경혈점 사이에서 임피던스 변화에 따른 경락전위를 측정하였다. 그 결과, 수기자극에서 측정된 전위패턴과 유사한 전위를 관찰하였으며, 다양한 자극에 대한 반응특성도 확인하였다. 따라서, 비침습 전자기장 자극을 통한 인체의 유도전류를 유발시킬수 있음을 확인하였다.

• 한국재료학회지
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• 제12권1호
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• pp.75-81
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• 2002

The ferroelectric properties of Pb(Zr,Ti)O$_3$[PZT] films degrade when the films with Pt top electrodes are annealed in hydrogen containing environment. This is due to the reduction activity of atomic hydrogen that is generated by the catalytic activity of the Pt top electrode. At the initial stage of hydrogen annealing, oxygen vacancies are formed by the reduction activity of hydrogen mainly at the vicinity of top Pt/PZT interface, resulting in a shift of P-E (polarization-electric field) hysteresis curve toward the negative electric field direction. As the hydrogen annealing time increases, oxygen vacancies are formed inside the PZT film by the inward diffusion of hydrogen ions, as a result, the polarization degrades significantly and the degree of P-E curve shift decreases gradually. The direction and the magnitude of the remnant polarization in the PZT film affect the motion of hydrogen ions which determines the degradation of polarization characteristics and the shift in the P-E hysteresis curve of the PZT capacitor during hydrogen annealing. When the remnant polarization is formed in the PZT film by applying a pre-poling voltage prior to hydrogen annealing, the direction of the P-E curve shift induced by hydrogen annealing is opposite to the polarity of the pre-poling voltage. The hydrogen-induced degradation behavior of the PZT capacitor is also affected by the internal field that has been generated in the PZT film by the charges located at the top interface prior to hydrogen annealing.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1078-1080
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• 1995

The pulsed electro-acoustic method was used as a nondestructive measurement technique of spare charge distribution in dielectric materials. In our work presented here, we measured simultaneously the space charge distribution and conduction current in the low-density polyethylene samples with elevated temperatures up to $80^{\circ}C$ and electric field up to 20kV/mm. In the temperature less than $50^{\circ}C$, homocharges are mainly accumulated close to the electrodes under DC bias and after grounding. At the temperature exeeds $50^{\circ}C$, heterocharges are accumulated near the opposite electrode under DC bias. However after grounding the upper electrode, this charges immediately disappeared. The conduction current in LDPE at $20^{\circ}C$ and $30^{\circ}C$ was reduced slowly with increasing interval of applied voltage. But as temperature increased, the conduction current tended to increase slowly with the time and the degree of increase is enlarged.

• 조명전기설비학회논문지
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• 제21권3호
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• pp.82-87
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• 2007

본 논문은 수용가에 대한 전력요금이 각 모선별로 부과될 경우 모선들의 전력품질을 측정하여 이를 비용화할 수 있다고 가정하였다. 이를 계통계획에 반영하여 예상되는 비용은 샘플계통을 통하여 다음과 같은 계산 방법을 제안하였다. 먼저 모선가격을 계산하기 위해서는 계통에서 전력설비의 운전조건은 최적조류계산에 의해 최적화되어 있는 상황으로 가정하여 모선가격[$/MVAH]을 산정하고, 계통의 각 모선에 연결된 부하들의 연중 발생하는 고장에 의해 탈락되는 피해비용을 산출하였다. 결과적으로 제안된 방법은 전력품질을 포함한 모선 총합 비용을 계산시 매우 효과적이였다.

• KIEAE Journal
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• 제5권1호
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• pp.43-49
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• 2005

People grow up and build up most of their character through living in dwelling space and have relax and refresh at home. Creating healthy dwelling space is being considered very important in architectural planning and design for providing comfortable living environment and improving quality of life. One of the properties of the earth is that the earth has a magnetic field associated with it- the Geomagnetic field. The geomagnetic field is produced by a combination of crustal rocks, external electric current systems that surround the earth that surround the earth and currents induced in the outer layers of the earth by magnetic field variations. Human beings have evolved with the background of magnetic field, they are accustomed to living in its presence. Geopathic stress occurs at geopathic zones where the geomagnetic field is disturbed. Geopathic zones exhibit magnetic charges. Geopathic zones are characterized by variations in geomagnetism, for the geomagnetic field is not uniform but exhibits many highly localized distortions, some random, some fairly regular. These occur in geological faults, caves and underground water channel. Many research papers and experiments of the western countries indicates that the geomagnetic field affects the people and living organism in dwellings. Therefore, it is necessary to investigate the geomagnetic field and people's response in living space. In this study the Health Hazard of geomagneic field in dwelling are studied through literature survey of related science field.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.597-601
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• 2001

Waste plastics amount is more than 3.5 million tons and 30% of industrial waste in 1998, Korea but recycling rate of industrial waste plastics is quite low because the material separation technology from the mixed waste plastic powders is not commercially available so far. This study covers the triboelectrostatic separation of polyvinylchloride (PVC) materials collection chambers and controllers. PVC and PET powders can be imparted negative and positive surface charges, respectively, due to the difference of triboelectric charging series between particles and particles in the fluidized bed tribocharger, and can be separated by passing them through an external electric field. The extract content and yield of PVC separation from the mixed PVC and PET plastic powders are 90.0% and 98.2%, respectively. The electrostatic separation system using the fluidized bed tribocharger shows the potential to be an effective method for removing PVC materials from other mixed plastics.

• JSTS:Journal of Semiconductor Technology and Science
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• 제6권2호
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• pp.101-105
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• 2006

Nanoscale floating-gate characteristic of colloidal Au nanoparticles electrostatically assembled on the oxidized surface of Si nanowires have been investigated. The Si nanowire split-gate transistor structure was fabricated by electron beam lithography and subsequent reactive ion etching. Colloidal Au nanoparticles with ${\sim}5$ nm diameters were selectively deposited onto the Si nanowire surface by 2 min electrophoresis. It was found that electric fields applied to the self-aligned split side gates allowed charge to be transferred on the Au nanoparticles. It was observed that the depletion mode cutoff voltage, induced by the self-aligned side gates, was shifted by more than 1 V after Au nanoparticle electrophoresis. This may be due to the semi-one dimensional nature of the narrow Si nanowire transport channel, having much enhanced sensitivity to charges on the surface.