• The Transactions of the Korean Institute of Electrical Engineers
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• v.32 no.7
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• pp.234-238
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• 1983

This paper presents a steady-state computer solution of one-dimensional transport equations, describing a double(metal-semiconductor-metal) contact device, involving only one type of charge carrier. Most of the assumptions and approximations which are ordinarily introduced in order to make the transport equations analytically soluble are avoided here. The results are presented mainly in the form of(a) energy contours (b) concentration contours and (c) I-V characteristics. A computation of differential system capacitance as a function of applied voltage is also presented and schematic corrections are introduced for image force effects.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.615-617
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• 2005

대기중에 위치한 뇌운안에 전하가 떠다니는 상태에서는 구름안과 주변에 높은 전계의 전위가 발생한다. 이 전하가 축적되면 대지 방전이 발생하고 송전선로 등에 뇌격이 침입하게 된다. 뇌 방전은 수 km에 달하는 대기중에 발생하는 거대한 전기현상이지만 이 낙뢰가 전기의 흐름이라는 것은 벤자민 프랭클린의 현장 시험에 대해 최초로 증명되었다. 이러한 대기중에 발생하는 거대한 전기현상인 낙뢰가 송전선로에 침입하여 송선선로 애자련을 섬락시키는 과정은 대단히 복잡한 전자기적인 현상이다. 그것은 가스 방전 현상, 감속에 중요한 역할을 하는 전자계의 빠른 변화, 도체와 철탑에 나타나는 코로 나와 관련된 비선형 효과 및 주파수 및 전류와 관련된 대지의 임피던스 통 다양한 현상이 종합적으로 관련된다. 따라서 가공 송전선로의 낙뢰에 대한 동작특성의 평가시 낙뢰 현상의 불규칙한 특성 및 신뢰할만한 데이터의 부족에 따른 많은 불확실성이 존재한다. 이 때문에 가공 송전선로에서 낙뢰에 의한 트립(Trip) 사고수의 계산을 위해 단순화된 방법이 아주 유용하며 효과적일 수 있다. 본 논문에서는 EGM (Electrogeometric Model) 모델을 사용하여 대지경사자의 크기에 따른 차폐실패 트립 사고율의 영향을 검토하였다.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.40 no.6
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• pp.442-446
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• 2003

This paper proposes a new two-stage two-phase VPP charge pump configured in such a manner that body effect and the threshold voltage loss are eliminated. The newly proposed circuit is fabricated using 0.18um triple-well CMOS process and the measurement result shows that the VPP level tracks 3VDD when VDD is above the threshold voltage.

• Proceeding of EDISON Challenge
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• 2013.04a
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• pp.125-137
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• 2013

2012년 G 단백질 연결 수용체(G-Protein Coupled Receptors ; GPCR) 연구가 노벨 화학상을 받았다. 상당히 많은 병과 관련되어 있어 잠재력이 크고, 많은 연구가 진행 중이다. 현재 리간드와 단백질간의 정전기적 포텐셜 연구를 통한 예측 연구가 진행되고 있지만, GPCR과 리간드 간의 연구에서 아직 리간드의 전하를 통한 단백질과 리간드간의 상호작용 예측 연구가 되어 있지 않다. 그렇기 때문에 이번 연구에서는 8가지 방법으로 전하(charge)를 띠게 하여서 단백질과 리간드의 상호작용을 계산을 통하여 예측하여 보았다.

• Journal of Life Science
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• v.16 no.1
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• pp.37-43
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• 2006

Gap junction is an ion channel forming between adjacent cells. It also acts as a membrane channel like sodium or potassium channels in a single cell. The amino acid residues up to the $10^{th}$ position in the amino (N)-terminus of gap junction hemichannel affect gating polarity as well as current-voltage (I-V) relation. While wild-type Cx32 channel shows negative gating polarity and inwardly rectifying I-V relation, T8D channel in which threonine residue at $8^{th}$ position is replaced with negatively charged aspartate residue shows reverse gating polarity and linear I-V relation. It is still unclear whether these changes are resulted from the charge effect or the conformational change of the N-terminus. To clarify this issue, we made a mutant channel harboring cysteine residue at the $8^{th}$ position (T8C) and characterized its biophysical properties using substituted-cysteine accessibility method (SCAM). T8C channel shows negative gating polarity and inwardly rectifying I-V relation as wild-type channel does. This result indicates that the substitution of cysteine residue dose not perturb the original conformation of wild-type channel. To elucidate the charge effect two types of methaenthiosulfonate (MTS) reagents (negatively charged $MTSES^-$ and positively charged $MTSET^+$) were used. When $MTSES^-$ was applied, T8C channel behaved as T8D channel, showing positive gating polarity and linear I-V relation. This result indicates that the addition of a negative charge changes the biophysical properties of T8C channel. However, positively charged $MTSET^+$ maintained the main features of T8C channel as expected. It is likely that the addition of a charge by small MTS reagents does not distort the conformation of the N-terminus. Therefore, the opposite effects of $MTSES^-$ and $MTSETT^+$ on T8C channel suggest that the addition of a charge itself rather than the conformational change of the N-terminus changes gating polarity and I-V relation. Furthermore, the accessibility of MTS reagents to amino acid residues at the $8^{th}$ position supports the idea that the N-terminus of gap junction channel forms or lies in the aqueous pore.

• The korean journal of orthodontics
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• v.33 no.4 s.99
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• pp.247-257
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• 2003

Various methods have been used on patients with skeletal Class II division 1 malocclusion. The activator, Frankel appliance, headgear, Herbst appliance, and Twin-block appliance are some examples. The ideal treatment effect using these appliances would be to inhibit horizontal and vertical growth of the maxilla while promoting mandibular growth and obtaining optimum dentition. The Teuscher appliance has a simultaneous combined headgear effect with maxillary growth inhibition and an activator effect with mandibular growth promotion. The purpose of this study was to examine how well these effects were clinically obtained and the results are as follows. 1. The forward growth of the maxilla was effectively inhibited. 2. The downward-forward growth of the maxillary dentoalveolar complex was inhibited. 3. Growth promotion of the mandible was not observed. 4. The overjet, overbite, molar key were effectively improved. 5. The protruded upper lip and facial profile were unproved.

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.348-348
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• 2012

CTF 메모리 소자는 높은 집적도와 낮은 구동전압과 CMOS 공정을 그대로 사용할 수 있고 비례 축소가 용이하다는 장점을 가지기 때문에 많은 연구가 진행되고 있다. CTF 메모리의 게이트 크기가 30 nm 이하로 작아짐에 따라 메모리 셀 간의 간섭이 매우 크게 증가하는 문제점이 있다. 이 문제점을 해결하기 위해 낸드 플래쉬 메모리 소자에서 셀 간 간섭 현상에 대한 많은 연구가 진행되고 있다. 본 연구에서는 $TaN-Al_2O_3-SiN-SiO_2-Si$ (TANOS) 플래쉬 메모리 소자에서 recess field의 모양에 따른 전기적 특성을 시뮬레이션 하였다. Recess field는 각 전하 트랩 층의 word 라인 방향에 존재하며 셀 간 간섭 효과를 줄이고 메모리 소자의 coupling ratio를 증가시키는 효과를 가지고 있다. TANOS 메모리 소자의 게이트 크기를 25 nm 에서 40 nm 로 변화하면서 round 타입의 recess field와 angular 타입의 recess field 에 대한 전기적 특성을 3차원 시뮬레이션 툴인 Sentaurus를 이용하여 시뮬레이션 하였다. Recess field를 가지지 않은 TANOS 메모리의 셀 간 간섭 효과는 게이트의 크기가 40 nm에서 25 nm 줄어들 때 많이 증가한다. 시뮬레이션된 결과에서 recess field의 모양에 상관없이 깊이가 늘어남에 따라 셀 간 간섭효과가 감소하였다. Recess field 의 깊이가 커짐에 따라 surrounding area가 늘어나 coupling ratio 가 증가하였다. Recess field 의 깊이가 증가함에 따라 프로그램 동작 시 트랩 층에 트랩 되는 전하의 수가 증가하고 recess field가 Si 기판의 표면에 가까이 위치할수록 coupling ratio, 드레인 전류 및 동작속도가 증가하였다. Recess field의 모양에 달리 하였을 때는 round 타입의 recess field를 가진 플래쉬 메모리 디바이스가 angular 타입의 recess field를 가진 소자와 비교하여 채널 표면의 잉여 전계가 감소하여 subthreshold leakage current 감소하였다. 본 연구의 시뮬레이션 결과는 수십 나노 스케일의 CTF 낸드 플래쉬 메모리 전기적 특성을 이해하는데 도움을 줄 것이다.

• Journal of Adhesion and Interface
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• v.24 no.2
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• pp.64-68
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• 2023

Organic field-effect transistors (OFETs) are attracting attention in the field of next-generation electronic devices, and they can be fabricated on a flexible substrate using an organic semiconductor as a channel layer. In particular, DPP-based semiconducting conjugated polymers are actively used because they have higher charge carrier mobility than other organic semiconductors, but they are still lower than inorganic semiconductors, so various studies are being conducted to improve the charge carrier mobility. In this study, the charge carrier mobility is improved by controlling the surface energy of the substrate by forming self-assembled monolayers (SAMs). As the surface energy of the substrate is controlled by the SAMs, the crystallinity increases, thereby improving the charge carrier mobility by 14 times from 3.57×10^-3 cm²V^-1s^-1 to 5.12×10^-2 cm²V^-1s^-1

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.49 no.2
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• pp.47-55
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• 2012

A discrete-time(DT) filter with high-order temporal moving average(TMA) using actively-weighted charge sampling is proposed in this paper. To obtain different weight of sampled charge, the variable transconductance OTA is used prior to charge sampler, and the ratio of charge can be effectively weighted by switching the control transistors in the OTA. As a result, high-order TMA operation can be possible by actively-weighted charge sampling. In addition, the transconductance generated by the OTA is relatively accurate and stable by using the size ratio of the control transistors. The high-order TMA filter has small size, increased voltage gain, and low parasitic effects due to the small amount of switches and sampling capacitors. It is implemented in the TSMC $0.18-{\mu}m$ CMOS process by TMA-$2^2$. The simulated voltage gain is about 16.7 dB, and P1dB and IIP3 are -32.5 dBm and -23.7 dBm, respectively. DC current consumption is about 9.7 mA.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1992.11a
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• pp.123-127
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• 1992

When MOS devices is exposed to radiation, radiation effects of P-type MOS capacitor can cause modulation and/or degradation in devices characteristics and its operating life. The oxide layer is grown in $O_2$+T.C.E. and its thickness ranges from 40 to 80 nm. Irradiations on MOS capacitor were performed by Cobalt-60 gamma ray source and total dose ranges from $10^4$ to $10^8$ rads. The radiation effect on electrical conduction characteristics(I-V) in MOS capacitor was measured as a function of gate oxide thickness and total dose. From the experimental result, I-V characteristics is found to be influenced strongly by total dose in irradiated p-type MOS capacitors. The ohmic current is dependant on of total dose in irradiated P-type MOS capacitors. This results are explained using surface states at interface radiation-induced traps.