• 전기의세계
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• 제29권8호
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• pp.524-531
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• 1980

In order to investigate the effect of inorganic dielectric fine particle mixed in Low Density Polyethylene on the deterioration by treeing, a comparative study for initiation and development of the tree has been carried out between the pure thin film specimen and the same geometrical specimen mixed with a constant weight percent by a defiend particle size of $Al_{2}$O$_{3}$ and SiO$_{2}$, having larger dielectric constants than that of the base material. According to the results, it has been observed that as increasing dielectric constant, the initiation of tree is expedited, however, the development of the tree reached at the surface of filler particles shows the suppressive trends. From these facts, a reasonable interpretation may be possible by considering the effect of intensified electrical field around the tip in the presence of filler particles, that the initiation and the development of tree are a mechanical break down process caused by Maxwell stress due to the concentration of electrical field at the tip. This suppressive effect is specifically suggestive for the reason that a discharge route must be constructed around the particle surface because of the intensified field strength near filler, which, in turn, reduces the geometrical curvature of the tip so that the local intensity of electrical field can be relaxed. Further more an experimental evidence for this assumption was able to observe in this investigation.

• 대한전자공학회논문지SD
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• 제45권4호
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• pp.49-56
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• 2008

본 논문은 효율적인 회로 시뮬레이션을 위한 긴 채널 공핍 모드 n형 나노선 전계효과트랜지스터(nanowire field-effect transistor: NWFET)의 간단한 해석적 전류 전도 모델을 소개한다. 본 연구에서 사용된 NWFET는 bottom-up 방식으로 제작되었으며 게이트가 채널의 아래에 존재하는 구조를 가진다. 이 모델은 다양한 바이어스 조건에서 동작하는 NWFET의 모든 전류 전도 메카니즘을 포함한다. 새롭게 개발된 NWFET 모델로 계산된 결과는 이전에 발표된 NWFET 실험 데이터와 비교할 때 10% 오차범위 안에서 서로 일치한다.

• 전자공학회논문지A
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• 제33A권10호
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• pp.107-114
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• 1996

Monte carlo method is especially a useful method for the analysis of thermal noise of semiconductor devices since the time dependence of microscopic details is simulated directly. Recently, a mthod for the calculation of the instantaneous currents of 2-dimensional devices, which is numerically more accurate than the conventional method, has been proposed using the generalized ramo-shockley theorem. Using this mehtod we investage the validity of the existing thermal noise theories of field-effect transistors. First, the 1-dimensional analysis of thermal noise theories of field-effect transistors. First, the 1-dimensional analysis of thermal noise theories of field-effect transistors. First, the 1-dimensional analysis of thermal noise using ramo-shockley theorem is shown to be applicable to 2 dimensional devices if the frequency of interest is low enough. The correlation between electrons in different regions of th echannel is shown not to be negligible. And we also obtian the spatial map of the noise in the channel region. By doing so, we show that the steady state nyquist theorem is the correct theory rather than the theory by van der ziel et.al.

• Nuclear Engineering and Technology
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• 제52권7호
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• pp.1380-1385
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• 2020

An annular linear induction electromagnetic pump (ALIP) which has a developed pressure of 0.76 bar and a flow rate of 100 L/min is designed to analysis end effect which is main problem to use ALIP in thermohydraulic system of the prototype generation-IV sodium-cooled fast reactor (PGSFR). Because there is no moving part which is directly in contact with the liquid, such as the impeller of a mechanical pump, an ALIP is one of the best options for transporting sodium, considering the high temperature and reactivity of liquid sodium. For the analysis of an ALIP, some of the most important characteristics are the electromagnetic properties such as the magnetic field, current density, and the Lorentz force. These electromagnetic properties not only affect the performance of an ALIP, but they additionally influence the end effect. The end effect is caused by distortion to the electromagnetic field at both ends of an ALIP, influencing both the flow stability and developed pressure. The electromagnetic field distribution in an ALIP is analyzed in this study by solving Maxwell's equations and using numerical analysis.

• Macromolecular Research
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• 제17권9호
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• pp.646-650
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• 2009

We report the fabrication of pentacene organic field-effect transistors (OFETs) using a fluorinated styrene-alt-maleic anhydride copolymer gate dielectric, which was prepared from styrene derivatives with a fluorinated side chain [$-CH_2-O-(CH_2)_2-(CF_2)_5CF_3$] and maleic anhydride through a solution polymerization technique. The fluorinated side chain was used to impart hydrophobicity to the surface of the gate dielectric and maleic anhydride was employed to improve its wetting properties. A field-effect mobility of 0.12 cm$^2$/Vs was obtained from the as-prepared top-contact pentacene FETs. Since various functional groups can be introduced into the copolymer due to the nature of maleic anhydride, its physical properties can be manipulated easily. Using this type of copolymer, the performance of organic FETs can be enhanced through optimization of the interfacial properties between the gate dielectric and organic semiconductor.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2016년도 추계학술대회
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• pp.611-613
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• 2016

TCAD 시뮬레이션을 이용하여 소스영역으로 오버랩된(overlapped) 게이트를 가진 터널링 전계효과 트랜지스터(Tunnel Field-Effect Transistor; TFET)의 오버랩된 게이트 길이에 따른 터널링 전류 특성을 조사하였다. 터널링은 크게 라인터널링과 포인트 터널링으로 구분되는데, 라인터널링이 포인트터널링보다 subthreshold swing(SS), on-current에서 더 높은 성능을 보인다. 본 논문은 Silicon, Germanium, Si-Ge Hetero TFET구조에서 게이트 길이를 소스영역으로 오버랩될 경우에 포인트 터널링과 라인터널링의 효과를 조사해서 SS와 on-current에 최적합한 구조의 가이드라인을 제시한다.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 추계학술대회
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• pp.115-117
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• 2022

피드백 전계 효과 트랜지스터(feedback field-effect transistor; FBFET)로 구성된 모놀리식 3차원 정적 랜덤 액세스 메모리(monolithic 3-dimensional static random access memory; M3D-SRAM)에 대해 TCAD(technology computer-aided design) 프로그램을 사용하여 전기적 특성을 조사하였다. FBFET로 구성된 M3D-SRAM(M3D-SRAM-FBFET)는 FDSOI(fully depleted silicon on insulator) 구조의 N형 FBFET와 N형 MOSFET(metal oxide semiconductor field effect transistor)로 이루어져 있으며 각각 하부와 상부에 위치한다. M3D-SRAM-FBFET의 메모리 동작 시, 공급 전압이 1.9 V에서 감소함에 따라 읽기 전류가 낮아졌으며, 공급 전압이 1.6 V 일 때 읽기 전류가 약 10배 감소하였다.

• 무역학회지
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• 제46권1호
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• pp.23-38
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• 2021

This paper investigated the preference change of payment terms in international trade along with counteroffer or first offer conditions of the other parties. Studies on trade payment terms have mainly focused on payment term determination factors such as firm size, product price level, country credit rate, etc. We tried to find other factors affecting payment terms choice, during the negotiation process. We applied behavioral economics theories such as 'Status Quo Bias' and 'Anchoring effect' to build our research model. To prove the existence of the above effects, we proceeded with field experiments to the exporting companies in Alibaba.com. Both 'Status Quo Bias' and 'Anchoring effect' were found in the field experiment. Most of the exporting companies preferred traditional payment methods to new payment methods. And an initial request for a low advance payment ratio led to a lower advance payment ratio. Also, the experience of using new payment methods could diminish status quo bias. This paper applied behavioral economics theories and field experiment methodology to the payment term studies in international trades. These attempts could contribute to expanding the diversity of methodology and scope of international trade studies.

• Earthquakes and Structures
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• 제10권4호
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• pp.757-768
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• 2016

In the past decades, effect of near field earthquake on the historical monuments has attracted the attention of researchers. So, many analyses in this regard have been presented. Tunnels as vital arteries play an important role in management after the earthquake crisis. However, digging tunnels and seismic effects of earthquake on the historical monuments have always been a challenge between engineers and historical supporters. So, in a case study, effect of near field earthquake on the historical monument was investigated. For this research, Finite Element Analysis (FEM) in soil environment and soil-structure interaction was used. In Plaxis 2D software, different accelerograms of near field earthquake were applied to the geometric definition. Analysis validations were performed based on the previous numerical studies. Creating a nonlinear relationship with space parameter, time, angular and numerical model outputs was of practical and critical importance. Hence, artificial Neural Network (ANN) was used and two linear layers and Tansig function were considered. Accuracy of the results was approved by the appropriate statistical test. Results of the study showed that buildings near and far from the tunnel had a special seismic behavior. Scattering of seismic waves on the underground tunnels on the adjacent buildings was influenced by their distance from the tunnel. Finally, a static test expressed optimal convergence of neural network and Plaxis.

• 한국환경보건학회지
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• 제34권6호
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• pp.403-413
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• 2008

Toxic effect of methyl tert-butyl ether (MTBE), tert-butyl alcohol (TBA) and formaldehyde (FA) on microbial activity and diversity was compared in rice field, leek patch, and tidal mud flat soil samples. MTBE, TBA and FA with different concentrations were added into microcosms containing these soil samples, and placed at room temperature for 30 days. Then the microbial activities such as dehydrogenase and viable cell numbers and microbial community using a DGGE (Denaturing gradient gel electrophoresis) fingerprinting method were measured. Among the samples, dehydrogenase activity in rice field was inhibited the most by MTBE, TBA and FA. The toxic effect was higher according to the following orders: FA > MTBE > TBA. Dominant species in the microcosms contaminated with MTBE, TBA and FA were Chloroflex, Bacilli, gamma-proteobacteria in the rice field sample, Sphingobacteria, Flavobacteria, Actinobacteria, Bacilli, gamma-proteobacteria in the leek patch sample, and Sphingobacteria, Flavobacteria, delta-proteobacteria, gamma-proteobacteria in the tidal mud flat sample.