• 대한전자공학회논문지
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• 제27권7호
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• pp.1049-1058
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• 1990

Mathematical modeling equations of a parallel plate type reactor were obtained in the PECVD process in preparing hydrogenated amorphous silicon. Velocity profiles, temperature profiles and concentration profiles in the reactor were calculated from the model. The theoretical approach was attempted to obtain the deposition rate and film uniformity at different operating conditions by calculating RF discharge parameters and establishing the reaction mechanisms of a-Si:H thin film. The modelling equations are solved by a finite difference method with control volume balance. The mean electrom energy in discharge was applied to model simulation parameter. The magnitudes of the predicted deposition rate are in good aggrement with those of experiment. The results of computer simulation shows that uniform deposition profiles can.

• 한국광학회지
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• 제10권4호
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• pp.335-341
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• 1999

홀로그램 기록 매질로 acrylamide를 기초한 포토폴리머를 제작하고 광화학 표백 특성을 측정하였다. 포토폴리머의 광화학 표백 특성을 설명하기 위해 잘 알려진 Beer-Lambert 모델과 간단한 에너지 qosem 모델로부터 얻어진 율방정식에 기초한 광표백 모델에 관한 이론들을 유도하였다. 본 연구에 사용된 포토폴리머에 대해 Beer-Lambert 모델은 짧은 시간 영역에 대해서만 실험 결과와 일치하였으나 율방정식에 기초한 이론적인 광표백 모델은 짧고 긴 시간 영역 모두에 대해서 실험 결과와 잘 일치하였다.

• 반도체디스플레이기술학회지
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• 제23권2호
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• pp.60-64
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• 2024

The threshold voltage shift in thin-film transistors (TFTs) is modeled using stretched-exponential (SE) and stretched-hyperbola (SH) functions. These models are derived by introducing empirical parameters into reaction rate equations that describe defect generation or charge trapping caused by hydrogen diffusion in the dielectric or interface. Separately, the dielectric relaxation phenomena are also described by the same reaction rate equations based on defect diffusion. Dielectric relaxation was initially modeled using the SE model, and various models have been proposed using fractional calculus. In this study, the characteristics of the threshold voltage shift and the dielectric relaxation phenomena are compared and analyzed to explore the applicability of analytical models used in the field of dielectric relaxation, in addition to the conventional SE and SH models.

• 한국안전학회지
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• 제9권1호
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• pp.61-67
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• 1994

Rate of rise heat detectors that respond to the heat generated in fire plume and alarm when the temperature reaches a specified point, give a great influences to the loss of life and property according to their reaction sensitivity. In this study, simple equations were derived which can be predicted the response time and temperature of the rate of rise heat detector with the results of hot wind tunnel tests and compartment fire experiments.

• 충청수학회지
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• 제37권1호
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• pp.27-40
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• 2024

In this paper, we consider the higher-order HartreeFock equations. The higher-order linear Schrödinger equation was introduced in [5] as the formal finite Taylor expansion of the pseudorelativistic linear Schrödinger equation. In [13], the authors established global-in-time Strichartz estimates for the linear higher-order equations which hold uniformly in the speed of light c ≥ 1 and as their applications they proved the convergence of higher-order Hartree-Fock equations to the corresponding pseudo-relativistic equation on arbitrary time interval as c goes to infinity when the Taylor expansion order is odd. To achieve this, they not only showed the existence of solutions in L² space but also proved that the solutions stay bounded uniformly in c. We address the remaining question on the convergence of higherorder Hartree-Fock equations when the Taylor expansion order is even. The distinguished feature from the odd case is that the group velocity of phase function would be vanishing when the size of frequency is comparable to c. Owing to this property, the kinetic energy of solutions is not coercive and only weaker Strichartz estimates compared to the odd case were obtained in [13]. Thus, we only manage to establish the existence of local solutions in H^s space for s > $\frac{1}{3}$ on a finite time interval [-T, T], however, the time interval does not depend on c and the solutions are bounded uniformly in c. In addition, we provide the convergence result of higher-order Hartree-Fock equations to the pseudo-relativistic equation with the same convergence rate as the odd case, which holds on [-T, T].

• 한국물환경학회지
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• 제33권2호
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• pp.123-129
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• 2017

The purpose of this study is to identify potential methodologies to reasonably estimate the effectiveness of road vacuum cleaning in terms of pollution loads reduction. In this context, this study proposes two empirical equations to estimate the amount of diffuse pollution loads removed by road vacuum cleaning. The proposed equations estimate the removed amount of pollution loads respectively taking into consideration of: a) the distance of road vacuum cleaning; and b) the amount of road-deposited sediment(RDS). All of the parameters in these equations were evaluated based on results of field monitoring and laboratory analyses, except for the RDS generation rate. The results of this study suggest that pollutant removal efficiency is 46.3% for $BOD_5$ and 56.4% for TP; discharge ratios for particulate and dissolved $BOD_5$ are 35.0% and 21.2%, respectively; discharge ratios for particulate and dissolved TP are 35.0% and 19.4%, respectively. Average concentrations of pollutants in RDS are $BOD_5$ 977.3 mg/kg and TP 317.6 mg/kg. Some results of a case study imply that both equations can be potentially useful if the adopted parameters are reasonably evaluated. In particular, the RDS generation rate should be evaluated based on monitoring data collected from various road conditions.

• 한국식품과학회지
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• 제21권2호
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• pp.212-217
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• 1989

무우 및 고구마를 열풍건조하고 건조가 진행됨에 따라 표면적 변화를 측정하여 실험치와 잘 일치하는 건조수축식과 총괄적 건조 속도식을 구하였으며, 시료의 두께, 상대습도 및 풍속을 포함한 초기 건조속도의 함수관계 식을 구하였다. 건조속도 상수와 차수는 시료의 두께와 공기의 온도에 영향을 받았으며 일정한 건조 (d=4mm, $Ta=50^{\circ}C$, RH=10%, U=0.8m/s) 하에서 얻어진 총괄적 건조속도 식과 수축식은 무우는 $dx/dt=0.112{\times}10^{-2}{\cdot}A{\cdot}:(1-x)^{0.43}$, A=Ao(-0.480x+1)이었고, 고구마는 $dx/dt=0.115{\times}10^{-2}\;A(1-x)^{0.49}$, A=Ao(-0.368x+1)이었다. 또한 초기 건조속도의 변화는 시료의 두께, 상대습도, 및 풍속에 대해 무우는 $dx/dt=0.0648\;(RH)^{-0.31}\;(d)^{-0.75}\;(U)^{0.39}$이었고, 고구마는 $dx/dt=0.0547(RH)^{-0.28}\;(d)^{-0.63}\;(U)^{0.37}$이었다.

• Ocean Systems Engineering
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• 제5권4호
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• pp.319-329
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• 2015

Submerged breakwaters are used to prevent shore line erosion and sediment transportation. One of their advantages is low visual impact. In this paper, the effects of discontinuous submerged breakwaters over water surface elevation was numerically studied considering the extended Boussinesq equations as governing equations using MIKE21 software. The result of discontinuous breakwater was compared with a beach without breakwater. The results showed that the gap dramatically effects on surface elevation from shore line to offshore. It is also evident from results that with approaching the center of the gap, fluctuation of surface elevation is generated. It is because of passing longshore currents towards offshore through the gap which leads to an increase in sediment transportation rate. Nevertheless, transferring water mass from breakwater gap results in powerful rip currents leading to high changes on longshore wave profile.

• 한국수소및신에너지학회논문집
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• 제21권6호
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• pp.513-518
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• 2010

In the present work the second-order perturbation solutions of the simple physical model for liquid pool spreading is obtained for the case of instantaneous spill. To generalize the solution governing equations are non-dimensionalized, and two dimensionless parameters, dimensionless evaporation rate and aspect ratio of the initial pool, are identified to control the governing equations. The dimensional governing equations have three parameters. The second-order solution improves fairly the first-order solution for the pool volume.

• Composites Research
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• 제27권4호
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• pp.130-134
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• 2014

본 논문에서는 Kim 등[7]이 제시한 4가지의 다른 밀도를 갖는 원통형 시험편으로한 EPP(Expanded polypropylene)의 준정적(Quasi-static test) 및 충격 시험(Impact test) DB를 바탕으로 Jeong 등[12]이 제시한 폴리우레탄(Polyurethane)에 대한 구성방정식을 EPP 폼에 대하여 다시 정의 하여 충격량-운동량 이론을 접목시켜 새로운 구성방정식을 제안하기위한 DB 구축을 목표로 하였다.