• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2000년도 하계학술대회 논문집 C
• /
• pp.1754-1756
• /
• 2000

Organic semiconductors based on fused-ring polycyclic aromatic hydrocarbon have great potential to be utilized as an active layer for electronic and optoelectronic devices. In this study, pentacene thin films and electrode materials were deposited by Organic Molecular Beam Deposition(OMBD) and vacuum evaporation respectively. For the gate dielectric, polyamic acid was spin-coated and cured into polyimide at 350$^{\circ}C$. Electrical characteristics of the devices were investigated, where the channel length and width was 50${\mu}m$ and 5mm. It was found that field effect mobility was 0.012$cm^{2}/Vs$, and on/off current ratio was $10^5$.

• 한국복합재료학회:학술대회논문집
• /
• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
• /
• pp.127-130
• /
• 2004

In this paper, active shape control of composite structure actuated by shape memory alloy (SMA) wires is presented. Hybrid composite structure was established by attaching SMA actuators on the surfaces of graphite/epoxy composite beam using bolt-joint connectors. SMA actuators were activated by phase transformation, which induced by temperature rising over austenite finish temperatures. In this paper, electrical resistive heating was applied to the hybrid composite structures to activate the SMA actuators. For faster and more accurate shape or deflection control of the hybrid composite structure, PID feedback controller was designed from numerical simulations and experimentally applied to the SMA actuators.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1999년도 추계학술대회 논문집
• /
• pp.586-589
• /
• 1999

Organic semiconductors based on conjugated thiophene oligomer have great potential to be utilized as an active layer far electronic and optoelectronic devices. In this study, $\alpha$ -sexithiophene($\alpha$-6T) thin films and various electrode materials were deposited by Organic Molecular Beam Deposition(OMBD) and vacuum evaporation respectively. Those films were photolithographically patterned fur measurements. Electrical characterization of the thin film transistor with various channel length were measured, and field effect mobility is calculated by formula.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2001년도 하계학술대회 논문집 D
• /
• pp.2243-2245
• /
• 2001

진동을 감소시키는 방법으로 과거에는 최적의 설계 변수를 선정하는 수동 제어 방법이 주로 연구되었으나, 보다 확실한 진동 제어를 위하여 최근에는 피드백 루프(Feedback loop)를 이용하는 능동제어에 대한 연구가 활발히 진행되고 있다. 본 연구에서는 능동제어에 의한 진동을 억제하는 방법에 대하여 연구하려고 한다. 진동체로는 외팔보를 선택하였으며 진동체의 진동을 제어하는 장치로는 제어코일과 베이스코일로 구성된 Push-Pull 타입의 전자석 제어회로를 직접 제작하고 시스템을 모델링 하고자 한다.

• Restorative Dentistry and Endodontics
• /
• 제42권1호
• /
• pp.65-71
• /
• 2017

A revascularization procedure was shown to be the best alternative therapy for immature teeth with necrotic pulp and apical infection. A 12 year old female with a history of trauma to her upper central incisor and a sinus tract was referred for endodontic treatment. She was an active orthodontic patient and had undergone regenerative endodontic treatment for the past 2 years. Clinical examination revealed no response to sensibility, percussion, and palpation tests. The preoperative radiograph showed an open apex and apical rarefaction. The case was diagnosed as previously treated tooth with asymptomatic apical periodontitis. Regenerative endodontic retreatment was performed, and the case was followed for 3 years. Clinical, radiographic, and cone-beam computed tomography follow-up examination revealed an asymptomatic tooth, with evidence of periapical healing and root maturation.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2007년도 제38회 하계학술대회
• /
• pp.1112-1113
• /
• 2007

능동형 자기베어링과 보(Beam)와 피봇으로 구성되는 시소 (SISO)는 제어적 관점에서 보면 많은 유사성이 있다. 본 논문에서는 Carl R. Knospe 등이 제안한 보와 피봇을 이용한 1자유도 자기베어링 시뮬레이터를 실제 제작하여, 비레 미분 적분 제어 알고리즘을 적용한 디지털 제어기와, 큰 힘을 발생시키기 위해서는 필연적인 전자석 코일의 큰 인덕턴스에 의해 제한되는 Bandwidth(BW)를 보상하기 위해 앞섬 보상기를 가지는 전류제어기를 구현하였다. 복잡한 자기베어링 시스템을 기구적으로 간단한 보와 피봇 시스템으로 상사시킴으로써, 자기베어링 제어 알고리즘 개발 및 파라미터 튜닝의 목적을 달성할 수 있었다.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2009년도 제38회 동계학술대회 초록집
• /
• pp.140-140
• /
• 2010

Non-mass analyzed ion shower doping (ISD) technique with a bucket-type ion source or mass-analyzed ion implantation with a ribbon beam-type has been used for source/drain doping, for LDD (lightly-doped-drain) formation, and for channel doping in fabrication of low-temperature poly-Si thin-film transistors (LTPS-TFT's). We reported an abnormal activation behavior in boron doped poly-Si where reverse annealing, the loss of electrically active boron concentration, was found in the temperature ranges between $400^{\circ}C$ and $650^{\circ}C$ using isochronal furnace annealing. We also reported reverse annealing behavior of sequential lateral solidification (SLS) poly-Si using isothermal rapid thermal annealing (RTA). We report here the importance of implantation conditions on the dopant activation. Through-doping conditions with higher energies and doses were intentionally chosen to understand reverse annealing behavior. We observed that the implantation condition plays a critical role on dopant activation. We found a certain implantation condition with which the sheet resistance is not changed at all upon activation annealing.

• Earthquakes and Structures
• /
• 제17권3호
• /
• pp.317-327
• /
• 2019

High-speed railway bridge piers in seismically active area may be subjected to multiple earthquakes and then produce cumulative residual deformation. To study the cumulative residual deformation of high-speed railway bridge piers under multiple earthquakes, a nonlinear numerical analytical model with multi-DOF (MDOF) system is presented and validated against two shaking table tests in this paper. Based on the presented model, a simple supported beam bridge pier model of high-speed railway is established and used to investigate the cumulative residual deformation of high-speed railway bridge pier under mainshock-aftershock sequences and swarm type seismic sequences. The results show that the cumulative residual deformation of the bridge pier increases with earthquake number, and the increasing rates are different under different earthquake number. The residual deformation of bridge pier subjected to multiple earthquakes is accumulated and may exceed the limit of code.

• Current Applied Physics
• /
• 제18권11호
• /
• pp.1399-1402
• /
• 2018

Nanorod films of cobalt oxide ($Co_3O_4$) have been grown by a unique oblique angle deposition (OAD) technique in an e-beam evaporator for supercapacitor electrode applications. This technique offers a non-chemical route to achieve large aspect ratio nanorods. The fabricated electrodes at OAD $80^{\circ}$ exhibited a specific capacitance of 2875 F/g. The electrochemically active surface area was $1397cm^{-2}$, estimated from the non-Faradaic capacitive current region. Peak energy and power densities obtained for $Co_3O_4$ nanorods were 57.7 Wh/Kg and 9.5 kW/kg, respectively. The $Co_3O_4$ nanorod electrode showed a good endurance of 2000 charge-discharge cycles with 62% retention. The OAD approach for fabricating supercapacitor nanostructured electrodes can be exploited for the fabrication of a broad range of metal oxide materials.

• Geomechanics and Engineering
• /
• 제30권4호
• /
• pp.353-362
• /
• 2022

The seismic failure-prone region in Istanbul has been examined in terms of the segmented pipelines. Although some researchers have suggested that this territory should be left as a green land, many people continue to live in this area. This region is about 9-10 km away from the North Anatolian Fault Line. This fault zone is an active right-lateral strike-slip fault line in Turkey and an earthquake with a magnitude of 7.0-7.5 is expected in the Marmara Sea. Therefore, superstructures and infrastructures are under both land sliding risks and seismic risks in this area. Because there are not any pipeline-fault line intersection points in the region, in this study, it has been focused on the behaviors of the segmented (sewage or stormwater) pipelines subject to earthquake-induced permanent ground deformation and seismic wave propagation. Based on the elastic beam theory some necessary analyses have been carried out and obtained results of this approximation have been examined.