• JSTS:Journal of Semiconductor Technology and Science
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• 제9권2호
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• pp.91-97
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• 2009

The performance of GaInP/GaAs tandem solar cells with AlInP growth temperatures of 680$^{\circ}C$ and 700 $^{\circ}C$ on n-type GaAs (100) substrate with 2$^{\circ}$ and 6$^{\circ}$ tilt angles has been investigated. The series resistance and open circuit voltage of the fabricated tandem solar cells are affected by the substrate tilt angles and the growth temperatures of the window layer when zinc is doped in the tunnel diode. With carbon doping as a p-type doping source in the tunnel diode and the effort of current matching between top and bottom cells, GaInP/GaAs tandem solar cell has been exhibited 25.58% efficiency.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2001년도 춘계종합학술대회
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• pp.311-316
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• 2001

소자의 고집적을 위한 특성분석 기술은 빠른 변화를 보이고 있다. 이에 따라 고집적 소자의 특성을 시뮬레이션을 통하여 이해하고 이에 맞게 제작하는 기술을 매우 중요한 과제 중의 하나가 되었다. 소자가 마이크론급에서 나노급 이하로 작아지면서 그에 맞는 소자개발을 위해 여러 가지 구조가 제시되고 있는데 본 논문에서는 TCAD를 이용하여 여러 가지 구조 중에서 고농도로 도핑된 ground plane 위에 적층하여 만든 EFI MOSFET와 LDD구조의 단점을 개선한 newEPI MOSFET에 대해 조사하였다. 이 구조의 특성과 임팩트이온화와 전계 그리고 I-V 특성 곡선을 저 농도로 도핑된 드레인(LDD) MOSFET와 비교 분석하였다. 또한 TCAD의 유용성을 조사하여 시뮬레이터로서 적합함과 나노구조 소자에서의 스켈링이론의 적합함을 보았다.

• 대한물리의학회지
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• 제10권4호
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• pp.123-131
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• 2015

PURPOSE: This study attempts to examine the impact of respiratory muscle exercises on the respiratory function and quality of sleep among stroke patients. METHODS: A total of 20 stroke patients were randomly divided into a breathing-exercise training group(n=10) and a breathing-device-training group(n=10). Changes in pulmonary function, as well as the quality, were measured before and after the intervention. The breathing exercise was performed three times a week for a total of eight weeks. Breathing-device exercises made use of a lung-capacity-strengthening device and were performed for three times a week for eight weeks. One Flow FVC was used as a measurement tool for the pulmonary function test. The Pittsburgh Sleep Quality Index(PSQI) and a sleep measurement tool were used for sleep evaluation. RESULTS: In a comparison of changes in pulmonary function before and after the training, the breathing-exercise group and the breathing-device-training group showed a significant difference. In changes of sleeping measure and PSQI, the breathing-exercise group and the breathing-device-training group also showed significant differences. CONCLUSION: Diverse index analyses confirmed that breathing exercises and exercises using a lung-capacity-strengthening device, were effective in improving respiratory function and quality of sleep among stroke patients experiencing respiratory function disorders and sleep disorders.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제52권10호
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• pp.469-475
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• 2003

Resistive leakage current flowing ZnO blocks increases with its ages, which is an important indicator of arrester deterioration. However, a complicated circuitry is essential to measure the resistive leakage current included in the total leakage current, and the difficult handling of the measurement makes few applications to the fields. In this paper, we propose a resistive leakage current measurement device which is composed of a current detection circuit and an analysis program operated on a microprocessor. The device samples the input leakage current waveform digitally, and discriminate the zero-cross and the peak point of the waveform to analyze the current amplitude vs. phase. The capacitive leakage current is then eliminated from the total leakage current by using an algorithm to extract the resistive leakage current only. Also, the device can be operated automatically and manually to analyze the resistive leakage current even when the leakage current waveform is distorted due to various types of arrester deterioration. To estimate the performance of the device, we carried out a test on ZnO blocks and lightning arresters. From the results, it is confirmed that the device could analyze most parameters needed for the arrester diagnostics such as total leakage current. resistive leakage current, and the $3^rd$ harmonic leakage current.

• 한국전문물리치료학회지
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• 제29권3호
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• pp.235-240
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• 2022

Background: A spinal extension and intensive rehabilitation program reduced the symptoms and pain of kyphosis, and improved function. Objects: This study aimed to demonstrate the effect of a spine extension device on the degree of thoracic kyphosis and extension angles, confirm reduction of the kyphosis angle and an increase in flexibility. Methods: Thirteen adults were enrolled in the experiment, using the spine extension device, which was set to passively extend the spine. The angle between the spinous process of the first thoracic vertebra and the spinous process of the twelfth thoracic vertebra was measured by dual inclinometer before and after using the spine extension device. Results: In the static posture, the thoracic kyphosis decreased after using the spine extension device in the thoracic extension posture, and there was a significant difference (p < 0.05); thoracic extension angle increased with statistical significance (p < 0.05). Conclusion: In this study, the thoracic kyphosis angle and thoracic extension angle of the subjects before and after using spine extension device was compared and analyzed, which proved that the spine extension device can effectively improve the mobility of spinal extension.

• 대한의용생체공학회:의공학회지
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• 제43권4호
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• pp.219-229
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• 2022

In this study, we propose a miniaturized micro-ceramic heater device. After screen-printing a silver paste between pre-sintered two aluminum oxide plates to integrate a heating circuit, the device was fabricated through a low-temperature sintering process. In order to configure the optimal heating circuit integration condition, the output current evaluation and heating test were performed according to the number of screen prints of the silver paste at various voltages. A silver paste-based heating circuit printed with a line width of 200 ㎛ and a thickness of 60 ㎛ was successfully integrated on a pre-sintered alumina substrate through a low-temperature sintering process. In the case of the 5 times printed device, the thermal response showed a response rate of 18.19 ℃/sec. To demonstrate feasibility of the proposed device in the medical field, such as bio-tissue suturing and hemostasis, a voltage was applied to pig tissue in the device to test tissue change due to heat generated from the device. These results show the possibility that the proposed small ceramic heater could be used in the medical field based on its excellent temperature response.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2009년도 하계학술대회 논문집
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• pp.152-152
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• 2009

We investigate micro-tip properties as Ni-Co plating and CMP processes for MEMS probe card and units. The micro-tip are fabricated by using Ni-Co plating machine, lapping machine, and chemo-mechanical polisher. In order to get high conductive and reliable micro-tip, we control Co contents and thickness by CMP speed. We have found that about 20-25% of Co contents are required and have to lapping speed of 30 rpm. Also, we investigate photolithography and Ni-Co plating processes conditions for the one-step and the three-step micro-tips.

• Ocean and Polar Research
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• 제36권4호
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• pp.475-485
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• 2014

Seawater flow characteristics around a manganese nodule mining device in deep sea were analyzed through numerical investigation. The mining device influences the seawater flow field with complicated velocity distributions, and they are largely dependent on the seawater flow speed, device moving speed, and injection velocity from the collecting part. The flow velocity and turbulent kinetic energy distributions are compared at several positions from the device rear, side, and top, and it is possible to predict the distance from which the mining device affects the seawater flow field through the variation of turbulent kinetic energy. With the operation of the collecting device the turbulent kinetic energy remarkably increases, and it gradually decreases along the seawater flow direction. Turbulent kinetic energy behind the mining system increases with the seawater flow velocity. The transient behavior of nodule particles, which are not collected, is also predicted. This study will be helpful in creating an optimal design for a manganese nodule collecting device that can operate efficiently and which is eco-friendly.

• 전기학회논문지
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• 제65권6호
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• pp.1103-1107
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• 2016

The automatic tensioning device of the catenary system constantly maintains the tension of the trolley wire by absorbing the variations due to the elasticity of the line caused by temperature variation. The tension plays an important role in affecting the electric motorcar operation directly. This paper suggests the methodology of the life cycle extension and the maintenance of the automatic tensioning device by means of performance diagnosis of the pulley type automatic tensioning device which has been commonly used for the electric railway system. Through conducting performance diagnosis and comparative test for the wornout pulley type automatic tensioning device by replacing the components such as the bearing and the bearing shaft without replacing all the assembly, the tensioning device is analyzed whether it is properly functioned. Provided that the maintenance regulation is reinforced so as to implement the bearing replacement through periodical precise inspection along with random check-up inspection which is now carried out by the operating organizations, it is ensured that the life cycle extension and the reduction of maintenance cost of the tensioning device could be achieved.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2012년도 추계학술대회
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• pp.495-497
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• 2012

의료기기 소프트웨어 테스트 위험관리 적용 방안에 대해 연구하였다. 먼저 설문조사를 통해 의료기기 제조업체의 소프트웨어 밸리데이션 및 위험관리 현황을 분석하고 두 번째로 블랙박스 테스트와 화이트 박스 테스트를 비교하여 차이점을 분석하였다. 세 번째로 소프트웨어 분석 도구를 활용한 코드 분석 후 잠재적인 위해요인을 도출하고 이를 정량화 하였으며, 마지막으로 도출된 위해요인을 FMEA 기법을 이용하여 의료기기 위험관리 프로세스에 적용할 수 있도록 프레임워크를 구축하였다. 이를 통해 의료기기 품질관리(GMP) 업무 중 소프트웨어 밸리데이션 및 위험관리 프로세스를 구축하기 어려운 제조업체를 위한 업무 지원에 활용하고자 한다.