• Transactions on Electrical and Electronic Materials
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• 제3권2호
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• pp.10-15
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• 2002

In this paper, the electrical characteristics of fabricated p+-n junction diode are demonstrated and interpreted with different theoretical calculations. Dopants distribution by boron ion implantation on silicon wafer were simulated with TRIM-code and ICECaEM simulator. In order to make electrical activation of implanted carriers, thermal annealing treatments are carried out by RTP method for 1min. at $1000^{circ}C$ under inert $N_2$ gas condition. In this case, profiles of dopants distribution before and after heat treatments in the substrate are observed from computer simulations. In the I-V characteristics of fabricated diodes, an analytical description method of a new triangular junction model is demonstrated and the results with calculated triangular junction are compared with measured data and theoretical calculated results of abrupt junction. Forward voltage drop with new triangular junction model is lower than the case of abrupt junction model. In the C-V characteristics of diode, the calculated data are compared with the measured data. Another I-V characteristics of diodes are measured after proton implantation in electrical isolation method instead of conventional etching method. From the measured data, the turn-on characteristics after proton implantation is more improved than before proton implantation. Also the C-V characteristics of diode are compared with the measured data before proton implantation. From the results of measured data, reasonable deviations are showed. But the C-V characteristics of diode after proton implantation are deviated greatly from the calculated data because of leakage currents in defect regions and layer shift of depletion by proton implantation.

• Biomolecules & Therapeutics
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• 제4권2호
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• pp.148-153
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• 1996

Activation of the T lymphocytes results in a variety of early biochemical events ultimately leading to cell proliferation and lymphokine production. Stimulation of the signal transduction cascade in T cells through the T cell receptor coincides with activation of the phosphatidylinositol-phospholipase C (PI-PLC) pathway. Therefore, we have established a model system to screen immune-simulator that can increase the hydrolysis of phosphoinositides in human T cell leukemia Jurkat cells. As a result of screening from herbal medicine extract, 4 extracts (O1ibanum, Ephedrae Herba, Real Gar, Saussureae Radix) were found 14 increase the production of inositol phosphates. All the active fraction from the four kinds of extract were fluted in a different retention time on C-18 HPLC and these active fraction also showed difference in cell specificity. And all the active fractions increased DNA synthesis in T cell. Therefore, it is suggested that the active fraction among 4 extracts might contain a compound having different properties one another.

• 전력전자학회논문지
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• 제20권6호
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• pp.498-508
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• 2015

In the simulation of photovoltaic (PV) power conditioning systems, PSIM is a widely accepted circuit simulation platform because of its fast speed and C-code support. PSIM provides two kinds of generic PV panel models: functional model and physical model. Whereas the functional model simulates PV in the standard test condition (STC) only, the physical model can emulate changing PV characteristics under varying temperatures and irradiation conditions and is thus more suitable for system simulation. However, the physical model requires complicated parameters from users, and thus it is prone to errors and is difficult to use. In this study, a new PSIM model for PV is presented to solve these problems. The proposed model utilizes manufacturers' datasheet values specified under STC only and excludes user-defined information from input parameters. To achieve good accuracy even in varying environmental conditions, single-diode model parameters are successively tuned to a time-varying virtual datasheet. Comparison with a conventional physical model shows that the proposed model provides more accurate simulation according to error analysis based on the EN50530 standard.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 하계종합학술대회 논문집(2)
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• pp.229-232
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• 2001

Modified Materka-Kacprzak 대신호 MESFET(Metal Semiconductor Field Effect Transistor) model을 사용하여 4H-SiC MESFET의 대신호 모델링을 수행하였다. Silvaco사의 소자 시뮬레이터인 ATLAS를 사용하여 4H-SiC MESFET 소자 시뮬레이션을 수행하고, 이 절과를 modified Materka 대신호 모델을 사용하여 모델링 하였다. 시뮬레이션 및 모델링 결과는 -8V의 pinch off 전압과 V/sub GS=0V, V/sub DS=25V에서 I/sub DSS=270㎃/㎜, G/sub m=45㎳/㎜를 얻을 수 있었고, 진력 특성 시뮬레이션을 통해 2㎓, V/sub GS=-4V, V/sub DS=25V에서 1()dB의 Gain과 34dBm(1dB compression point)의 출력전력, 7.6W/㎜의 전력밀도, 37%의 PAE(power added efficiency)를 얻을 수 있었다.

• 한국항공우주학회지
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• 제35권9호
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• pp.783-791
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• 2007

FAA AC 120-63 등급 C 또는 FTD 등급 5에 규정된 헬리콥터 모의 비행 훈련장치에 사용될 단일 로터 회전익기의 수학적 모델에 대해 고찰하였다. 선정된 비행 운동 모델의 비행 운동 성능 평가를 통해서 그 유용성을 파악하였다. 이로부터 훈련은 물론 조종 성능시험이 가능한 비행 훈련장치 개발을 통해서 헬리콥터 비행성 평가를 위한 모의 비행 시험환경을 구현하였다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 추계학술대회 논문집
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• pp.231-234
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• 2005

The high temperature deformation behavior of AZ 31 Mg alloy was investigated by designing a back propagation neural network that uses a gradient descent-learning algorithm. A neural network modeling is an intelligent technique that can solve non-linear and complex problems by learning from the samples. Therefore, some experimental data have been firstly obtained from continuous compression tests performed on a thermo-mechanical simulator over a range of temperatures $(250-500^{\circ}C)$ with strain rates of $0.0001-100s^{-1}$ and true strains of 0.1 to 0.6. The inputs for neural network model are strain, strain rate, and temperature and the output is flow stress. It was found that the trained model could well predict the flow stress for some experimental data that have not been used in the training. Workability of a material can be evaluated by means of power dissipation map with respect to strain, strain rate and temperature. Power dissipation map was constructed using the flow stress predicted from the neural network model at finer Intervals of strain, strain rates and subsequently processing maps were developed for hot working processes for AZ 31 Mg alloy. The safe domains of hot working of AZ 31 Mg alloy were identified and validated through microstructural investigations.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 1999년도 제14차 학술회의논문집
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• pp.37-40
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• 1999

ETRI has successfully completed and delivered to KARI the KOMPSAT Mission Control System. This system was designed to work in the conventional TT&C modulation scheme with the pre-assigned frequencies. As a way to accelerate in catching up with future TT&C technology evolutions, a preliminary study needs to be carried out to prepare for the development of a spread spectrum applicable to TT&C. A brief study was carried out to review some points to be considered in designing and implementing spread spectrum schemes to the ground TT&C system intended for a LEO spacecraft. Also a simulation and link design revisit was performed to see the operational and technical benefits with the KOMPSAT TT&C parameters. An experiment concept is proposed to test as many functions at a time once the prototype is developed. In this configuration, a ground-model TT&C transponder is connected via LAN to the ETRI-developed KOMPSAT S/W simulator and linked to the KOMPSAT TM/TC processing s/w via spread spectrum signals through a GEO satellite bent-pipe link. A satellite data relay link simulation could be carried out in this configuration.

• 한국전기전자재료학회논문지
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• 제22권2호
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• pp.128-131
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• 2009

Silicon carbide (SiC) has attracted significant attention for high frequency, high temperature and high power devices due to its superior properties such as the large band gap, high breakdown electric field, high saturation velocity and high thermal conductivity. We performed Al ion implantation processes on n-type 4H-SiC substrate using a SILVACO ATHENA numerical simulator. The ion implantation model used Monte-Carlo method. We simulated the effect of channeling by Al implantation in both 0 off-axis and 8 off-axis n-type 4H-SiC substrate. We have investigated the effect of varying the implantation energies and the corresponding doses on the distribution of Al in 4H-SiC. The controlled implantation energies were 40, 60, 80, 100 and 120 keV and the implantation doses varied from $2{\times}10^{14}$ to $1{\times}10^{15}\;cm^{-2}$. The Al ion distribution was deeper with increasing implantation energy, whereas the doping level increased with increasing dose. The effect of post-implantation annealing on the electrical properties of Al-implanted p-n junction diode were also investigated.

• 한국화재소방학회논문지
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• 제27권2호
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• pp.31-39
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• 2013

원자력발전소의 강제 환기가 적용된 밀폐된 다중구획에서 실규모 pool 화재를 모사하기 위하여 FDS가 적용되었다. FDS의예측성능은 수치결과와 OECD/NEA 화재실증실험 국제공동연구 프로젝트(PRISME)를통해 얻어진 실험결과의비교를 통해 평가되었다. 단순한 연소모델의 적용으로 발생되는 FDS의 본질적인 한계를 제외하고 FDS 수행과정에서 발생된 사용자 의존성에 따른 FDS의 예측결과 차이를 명확히 확인하기 위하여, 과환기 화재조건이 본 연구에서 검토되었다. 특히 강제 환기시스템에서 정확한 경계조건의 중요성이 상세하게 논의되었다. 급기 및 배기를 위한 환기구의 경계조건은 구획 내부의 열 및 화학적특성에 큰 영향을 주고 있음을 FDS 결과를 통해 알 수 있었으며, 정확한 경계조건이 부여된 FDS는 원전 타입의 다중 구획 내부의 온도, 열유속 및 화학종 농도를 정량적으로 잘 예측하고 있음을 확인하였다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2000년도 춘계학술대회논문집A
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• pp.666-671
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• 2000

In this paper, we developed a Windows 95 version off-line programing system which can simulate a track vehicle model in 3D graphics space. The track vehicle was adopted as an objective model. The interface between users and the off-line program system in the Windows 95's graphic user interface environment was also studied The developing language is Microsoft Visual C++. Graphic libraries, OpenGL, by Silicon Graphics, Inc. were utilized for 3D Graphics.