• 한국조명전기설비학회:학술대회논문집
• /
• 한국조명전기설비학회 2000년도 학술대회논문집
• /
• pp.179-182
• /
• 2000

This paper investigates characteristics of spiral charge for charge simulation method to calculate electric fields of spiral conductor bundles with spiral rods in 765 kV transmission line. We finds the simulating spiral charge as constant charge density give less potential calculation error than sinusoidal charge density. When a spiral rod is simulated as spiral charge, we also knows two spiral charge can simulate spiral rod best.

• 한국마린엔지니어링학회:학술대회논문집
• /
• 한국마린엔지니어링학회 2005년도 후기학술대회논문집
• /
• pp.15-16
• /
• 2005

In this study, the characteristics of NOx reduction by using charge air moisturizer system were evaluated by engine performance simulation in medium speed diesel engines. The results of performance simulation were verified by experimental results of single cylinder medium speed diesel engine equipped with charge air moisturizer system. Performance simulation was carried out to evaluate charge air moisturizer system of turbocharged diesel engine, HYUNDAI HiMSEN 9H25/33 engine. Those results show 50% NOx reduction at dew point $80^{\circ}C$ and charge air pressure 4bar.

• 한국초등과학교육학회지:초등과학교육
• /
• 제34권4호
• /
• pp.357-371
• /
• 2015

Even after learning electric current, elementary school students have various non-scientific conceptions and difficulties. Because flow of charge is not visible. Also elementary school students do not learn theory but phenomena, so they cannot transfer theoretical perspective to new situation. In this research, we have designed instruction based on PhET simulation visualizing flow of electric charge and applied it to 37 science-gifted students in elementary school for measuring conceptual understanding. As a result, six out of the seven Hake gains of question set are high gain and just one is middle gain because the students have understood the flow pattern of the charge through circuit elements such as light bulbs, wire, as well as battery with PhET simulation and it gives a chance to create various questions spontaneously about electric current. Also they become able to do spontaneous mental simulation without PhET simulation about flow of charges. This research, suggest that developed materials using PhET simulation could be used as not only program for gifted students in elementary school, but also the electrical circuit section in an elementary science curriculum.

• 한국군사과학기술학회지
• /
• 제12권3호
• /
• pp.378-387
• /
• 2009

The shaped charge consists of the cast or pressed explosive and the metal liner. The pressure formed in detonation wave is so high that the liner is collapsed and the jet of high temperature, pressure and velocity is produced. The jet penetrates the target. In this paper, the simulation for optimization of flexible linear shaped charge(FLSC) was carried out by AUTODYNE program. Based on the results of simulation, we made a prototype of FLSC and evaluated penetration performance, flexibility and its application. The test result of prototype was compared with that of simulation.

• Journal of Electrical Engineering and Technology
• /
• 제1권2호
• /
• pp.233-236
• /
• 2006

A 3-D numerical simulation of a buried-channel CCD (Charge Coupled Device) with a deep depletion has been performed to investigate its electrical and physical behaviors. Results are presented for a deep depletion CCD (EEV CCD12; JET-X CCD) fabricated on a high-resistivity $(1.5k\Omega-cm)\;65{\mu}m$ thick epi-layer, on a $550{\mu}m$ thick p+ substrate, which is optimized for X-ray detection. Accurate predictions of the Potential minimum and barrier height of a CCD Pixel as a function of mobile electrons are found to give good charge transfer. The depletion depth approximation as a function of gate and substrate bias voltage provided average errors of less than 6%, compared with the results estimated from X-ray detection efficiency measurements. The result obtained from the transient simulation of signal charge movement is also presented based on 3-Dimensional analysis.

• 조명전기설비학회논문지
• /
• 제15권4호
• /
• pp.31-36
• /
• 2001

본 논문은 765[kV] 송전선로의 풍소음 저감용 spiral rod의 전계를 계산하기 위해서 3차원 전하중첩법용 나선 전하의 특성에 관해 연구하였다. 본 연구에서 나선전하를 정현 함수 전하로 모의하는 것 보다 상수전하로 모의한 것이 전위오차가 적었고, 상수전하를 한 개로 모의하는 것 보다 2개를 배치하여 계산했을 때 spiral rod의 전하를 가장 잘 모의할 수 있는 것으로 나타났다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1994년도 추계학술대회 논문집 학회본부
• /
• pp.290-292
• /
• 1994

This paper presents a methodology for the electric field analysis of substation. For the electric field analysis of substation, the electrodes(substation busbars) must be represented by finite line with nonlinear charge density. In the case of dividing finite line into uniform segments, a large number of variables have to be used to obtain the accuracy within a desired tolerance. To deal with the problem, nonuniform charge arrangement modeling method is suggested. To reduce potential calculation errors, the linear charge density function is considered particularly for the segment charge model ling. If the charge arrangement is improper, the accuracy not improved regardless of increment in the number of segments. This paper proposes an optimal charge arrangement method through potential error analysis. And, the optimal charge arrangement function is formulated by a lot of simulation results.

• 에너지공학
• /
• 제24권3호
• /
• pp.61-66
• /
• 2015

Homogeneous charge compression ignition (HCCI) engine combines the combustion characteristics of a compression ignition engine and a spark ignition engine. HCCI engines take advantage of the high compression ratio and heat release rate and thus exhibit high efficiency found in compression ignition engines. In modern research, simulation has be come a powerful tool as it saves time and also economical when compared to experimental study. Engine simulation has been developed to predict the performance of a homogeneous charge compression ignition engine. The effects of compression ratio, cylinder pressure, rate of pressure rise, flame temperature, rate of heat release, and mass fraction burned were simulated. The simulation and analysis show several meaningful results. The objective of the present study is to develop a combustion characteristics model for a homogeneous charge compression ignition engine running with isooctane as a fuel and effect of compression ratio.

• 전력전자학회논문지
• /
• 제14권5호
• /
• pp.387-396
• /
• 2009

리튬전지는 생산과정에서의 핵심인 화성공정에 의해 수명 및 성능이 크게 좌우되며, 화성공정을 처리하기 위해서 충방전 시스템이 필수적으로 요구되고 있다. 리튬전지 충방전 시스템의 특성을 해석하기 위해 일반적인 방법으로 시뮬레이션하면 충전동작과 방전동작에 엄청난 시간이 소요되고 메모리 용량의 한계로 인해 범용 PC로는 시뮬레이션이 어렵다. 본 논문에서는 리튬전지를 저항-커패시터 직렬회로로 모델링하였으며 상태공간평균의 개념을 적용하여 리튬전지 충방전 시스템을 해석하고 시뮬레이션하였다. Simplorer를 사용하여 시뮬레이션을 수행한 결과 시뮬레이션 시간이 단축되어 범용 PC로도 3시간 내에 시뮬레이션이 가능해졌으며, 리튬전지 충방전 시스템의 정전류/정전압 충전 특성 및 정전류 방전 특성과 충방전 소요시간을 예측할 수 있었다. 또한 충방전 시스템을 구성하고 실험하여 리튬전지를 저항-커패시터 직렬회로로 등가화한 모델링의 타당성과 상태공간평균의 개념을 사용하여 해석하고 시뮬레이션한 방법의 유용성을 입증하였다.

• 설비공학논문집
• /
• 제12권5호
• /
• pp.486-493
• /
• 2000

A theoretical model for the transient performance of vapor-compression air-conditioning system has been developed to evaluate the influence of the refrigerant charge on the system performance. A set of mass and energy equations for the simulation of the heat exchangers and the capillary tube and a polytropic compression model for the compressor are used. The present model successfully predicts the transient behavior of the vapor-compression air-conditioner from the startup. As the refrigerant charge is increased, both the evaporating and condensing pressures increase gradually, and the cooling rate and the COP show a maximum in the range of 0.75-0.8 kg of refrigerant charge. This amount of refrigerant mass is determined to be the optimum charge of the model system. Also, the effect of outdoor air temperature on the optimum refrigerant charge is discussed.