• 전기학회논문지P
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• 제51권4호
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• pp.219-221
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• 2002

This paper presents an electric scooter development using blushless DC motor. In recent scooters was to develop for sport leisure and short transportation. Most of scooter are used petroleum gas. This gas scooter has disadvantage to pollute the air. Some of scooters have developed by DC motor which require a brush. However brushless motors have higher maximum speed and greater capacity, save maintenance labour and produce less noise. There is also greater freedom in planing the usage of brushless motors. In this paper we develop an electric scooter driving BLDC motor for design smart system and control speed of scooter with current reference signal to apply voltage to motor by means of three phase inverter. Using accelerator device we generate current reference to control speed and send the current to a MICOM by A/D converter. This MICOM produces the voltage signal and hall sensors signal and PWM controller drive three phase inverter to minimize error between the reference and an actual current.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제55권1호
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• pp.26-29
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• 2006

Transparent ZnO thin films were prepared by KrF pulsed laser deposition (PLD) technique and applied to a bottom-gate type thin film transistor device as an active channel layer. A high conductive crystalline Si substrate was used as an metal-like bottom gate and SiN insulating layer was then deposited by LPCVD(low pressure chemical vapour deposition). An aluminum layer was then vacuum evaporated and patterned to form a source/drain metal contact. Oxygen partial pressure and substrate temperature were varied during the ZnO PLD deposition process and their influence on the thin film properties were investigated by X-ray diffraction(XRD) and Hall-van der Pauw method. Optical transparency of the ZnO thin film was analyzed by UV-visible phometer. The resulting ZnO-TFT devices showed an on-off ration of $10^6$ and field effect mobility of 2.4-6.1 $cm^2/V{\cdot}s$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 제4회 영호남학술대회 논문집
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• pp.128-132
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• 2002

Many compound semiconductors which have high carrier mobility and small band gap have attentive in application of various practical a field. Especially, InSb served for Hall device and magnetic resistor such as magnetic sensor because InSb thin film has high mobility. Many studies on InSb thin film deposistion because In and Sb has been very different feature of vapor pressure($10^{-4}$ times) When In and. Sb deposited. In this paper studied it In and Sb deposited simultaneously using by method of co-sputtering deposotion. This process, get to effects of manufacture process simplification. After that this paper observed micro structure and electronic behavior of InSb thin film using by co-sputtering and we study properties of magneto-resistance by annealing

• 한국기후변화학회지
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• 제6권2호
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• pp.143-158
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• 2015

This study developed the emission intensity estimation method of GHGs by considering the characteristics of the models and time series. The telematics device was installed on the vehicle (OBD-II) to collect information on the operation conditions from each sample vehicle of public authorities. As a result of comparing the mileage distance and fuel consumption, the matching degree is analyzed very high, showed a ${\pm}1{\sim}4%$ error for each vehicle. By comparing driving record diary of vehicles managed by public authorities, this study presents the method that can be used to verify driving information in order to derive the GHGs emission intensity.

• 한국자기공명학회논문지
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• 제23권2호
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• pp.46-50
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• 2019

Spin orbit torque would be applied as the next generation of MRAM, so many researchers are interested in related field. To make a more efficient device, electric current should convert into spin current with high efficiency. Moreover, it becomes important to measure efficiency of spin orbit torque accurately. We measured spin torque FMR of W/CoFeB hetero structure system with direct current. The efficiencies of the damping like torque and field like torque were measured by using the linewidth and on-resonance field proportional to direct current. In addition, we analyzed that a quadratic shift of the on-response field was caused by the Joule heating.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.280-283
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• 2007

The first grid-connected, building-integrated transparent amorphous silicon photovoltaic installation has been operated since October 2004 in Yongin, Korea. The 2.2kWp transparent PV system was applied to the facade of entrance hall in newly constructed KOLON E&C R&D building. The PV module is a nominal 0.98m ${\times}$ 0.95m, 10% transparent, laminated, amorphous(a-Si) thin-film device rated at 44 Wp per module. To demonstrate the architectural features of thin film PV technologies for daylighting application, transparent PV modules are attached to the building envelope with the form of single glazed window and special point glazing(SPG) frames. Besides power generation, the 10% transmittance of a-Si PV module provides very smooth natural daylight to the entrance hall without any special shading devices for whole year. The installation is fully instrumented and is continuously monitored in order to allow the performance assessment of amorphous silicon PV operating at the prevailing conditions. This paper presents measured power performance data from the first 12 months of operation. For the first year, annual average system specific yield was just 486.4kWh/kWp/year which is almost half of typical amorphous silicon PV output under the best angle and orientation. It should be caused by building orientation and self-shading of adjacent mass. Besides annual power output, various statistical analysis was performed to identify the characteristics of transparent thin film PV system.

• JSTS:Journal of Semiconductor Technology and Science
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• 제15권5호
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• pp.490-496
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• 2015

We have grown AlN/GaN heterostructure which is a promising candidate for mm-wave applications. For the growth of the high quality very thin AlN barrier, indium was introduced as a surfactant at the growth temperature varied from 750 to $1070^{\circ}C$, which results in improving electrical properties of two-dimensional electron gas (2DEG). The heterostructure with barrier thickness of 7 nm grown at of $800^{\circ}C$ exhibited best Hall measurement results; such as sheet resistance of $215{\Omega}/{\Box}$electron mobility of $1430cm^2/V{\cdot}s$, and two-dimensional electron gas (2DEG) density of $2.04{\times}10^{13}/cm^2$. The high electron mobility transistor (HEMT) was fabricated on the grown heterostructure. The device with gate length of $0.2{\mu}m$ exhibited excellent DC and RF performances; such as maximum drain current of 937 mA/mm, maximum transconductance of 269 mS/mm, current gain cut-off frequency of 40 GHz, and maximum oscillation frequency of 80 GHz.

• 한국재료학회지
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• 제22권10호
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• pp.508-512
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• 2012

ZnO thin films were grown on a sapphire substrate by RF magnetron sputtering. The characteristics of the thin films were investigated by ellipsometry, X-ray diffraction (XRD), atomic force microscopy (AFM), photoluminescence (PL), and Hall effect. The substrate temperature and growth time were kept constant at $200^{\circ}C$ at 30 minutes, respectively. The RF power was varied within the range of 200 to 500 W. ZnO thin films on sapphire substrate were grown with a preferred C-axis orientation along the (0002) plan; X-ray diffraction peak shifted to low angles and PL emission peak was red-shifted with increasing RF power. In addition, the electrical characteristics of the carrier density and mobility decreased and the resistivity increased. In the electrical and optical properties of ZnO thin films under variation of RF power, the crystallinity improved and the roughness increased with increasing RF power due to decreased oxygen vacancies and the presence of excess zinc above the optimal range of RF power. Consequently, the crystallinity of the ZnO thin films grown on sapphire substrate was improved with RF sputtering power; however, excess Zn resulted because of the structural, electrical, and optical properties of the ZnO thin films. Thus, excess RF power will act as a factor that degrades the device characteristics.

• 영재교육연구
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• 제26권2호
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• pp.235-255
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• 2016

본 연구는 영재교육기관 컨설팅에 대한 관심도를 조사하기 위하여, 영재교육 이해관계자를 대상으로 설문을 실시하였다. 122명의 이해관계자가 SoCQ(The Stages of Concerns Questionnaire, Hall & Hord, 2011)에 응답하였으며, Hall과 Hord(2011)의 채점표(SoCQ scoring device)를 활용하여 이해관계자의 응답 반응을 상대적 강도(relative intensity)로 환산하였다. 본 연구는 영재교육 이해관계자의 특성(소속기관, 영재교육경력, 영재업무 지속여부, 영재 연수유형)에 따른 영재교육기관 컨설팅에 대한 관심도를 살펴보기 위하여 t 분석과 일원분산분석을 실시하였다. 연구결과, 영재교육 이해관계자들은 1단계(정보)에 대한 관심이 가장 높고, 4단계(결과)에 대한 관심이 가장 낮은 변화초기 단계의 양상을 보여주었다. 한편, 전문가 연수를 받은 이해관계자들은 6단계(재조정)에 대한 관심도가 높게 나타나, 영재교육기관 컨설팅에 대하여 저항을 보이는 것으로 나타났다. 이에 본 연구에서는 연구결과에 기초하여 성공적인 영재교육기관 컨설팅을 정착하고 확산하는 방안을 제안하였다.

• 마이크로전자및패키징학회지
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• 제14권3호
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• pp.1-6
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• 2007

본 연구에서는 유기박막트랜지스터(OTFT, Organic Thin film Transistor)에 응용을 위해 용액(soluble) 공정을 통하여 제작된 pentacene 박막의 특성을 분석하여 pentacene 박막의 OTFT 소자에 적용 가능성을 조사하였다. Pentacene을 용해시키기 위해 toluene과 chloroform의 두 종류의 용제를 사용하였으며, 이들 용제가 pentacene 박막의 특성에 미치는 영향을 연구하였다. Pentacene 용액은 ITO/Glass 기판위에 spin-coating 법으로 유기 반도체 박막을 제작하여 각 박막의 표면형상, 결정화 특성과 전기적 특성을 조사하였다. AFM을 이용한 표면 형상 관찰 결과 chloroform을 이용한 pentacene 박막이 toluene을 이용한 박막에 비하여 표면 거칠기가 개선되는 경향을 보여주었다. XRD 회절 분석 결과 모든 pentacene 박막 시료에서 결정화가 되지 않은 비정질 형태를 보여주었다. Hall effect measurement 분석 결과 chloroform 용제를 이용한 pentacene 박막이 toluene용제를 사용한 시료에 비해 보다 우수한 전기적 특성을 나타내었다. 즉, chloroform에 용해된 pentacene 박막의 경우 전하농도와 이동도는 $-3.225{\times}10^{14}\;cm^{-3}$와 $3.5{\times}10^{-1}\;cm^2\;V^{-1}{\cdot}S^{-1}$를 각각 나타내었다. 또한 비저항은 약 $2.5{\times}10^2\;{\Omega}{\cdot}cm$를 얻었다.