• 대한방사선기술학회지:방사선기술과학
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• 제41권6호
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• pp.603-610
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• 2018

This study examined the following: accuracy of the exposure conditions in the inverter device and three-phase device; output waveform over the exposure conditions; and average and standard deviation of the output waveform. After assessing whether the dose corresponding to the theoretical dose was presented, the following conclusions were obtained: 1. The accuracy of the tube voltage(kVp) and tube current(mA) exposure time(sec) was within the tolerable level prescribed in Korea's Safety Management Standards. In the error, Inverter device was large the tube voltage and exposure time, the three-phase device was large the tube current. 2. In terms of the output waveform of the exposure conditions and the average and standard deviation of the output waveform, the higher tube voltage and larger tube current resulted in greater standard deviation in pulsation. Moreover, the standard deviation of pulsation was shown to be greater in the inverter device than the three-phase device; there was also greater standard deviation in the inverter device considering the exposure time. 3. Regarding the exposure conditions over the output dose, all linearity showed the coefficient of variation which had an allowable limit of error within 0.05. Although the output dose ratio for the inverter device was 1.00~1.10 times no difference that of the three-phase device, there was almost no difference in dose ratio between the tube currents.

• 방사성폐기물학회지
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• 제12권1호
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• pp.79-88
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• 2014

원자력이용시설에서 발생한 작은 크기의 금속 조각들을 효과적으로 제염하는 스마트 장치를 개발하였다. 이 장치는 자성연마재를 포함한 영역의 자속밀도를 연속적으로 변화시키는 방법과 초음파를 이용하는 다중 제염장치이다. 한편, 제염 효율을 높이기 위해 제염 장치가 제염 대상 전체에 작용하도록 장치들의 구성을 수정하였다. 개발된 장치들의 최적 작동조건을 도출하여 샘플로 선정한 소형의 금속방사성페기물에 대하여 자기장과 초음파제염을 각각 15분간 실시하였다. 그 결과 제염계수의 범위는18~56으로 크게 향상되었으며 제염 후 모든 샘플은 백그라운드(BKG)값 이하로 확인되었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.245-248
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• 2000

This paper presents the test and operation results of the domestic demonstration of the reactive power compensation device called STATCOM (STATic COMpensator). The object of the paper is to describe the reliability of the unit based on the extensive operation databases. By controlling reactive power, the technology offers utilities the opportunity for increased efficiency and their capabilities will permit transmission planners make the best use of their existing transmission resources STATCOM is a custom power device in a way and can be used in a similar way for the dynamic compensation of power transmission systems, mitigation of voltage flicker and improving the power factor. It is shown that the STATCOM has clear advantages in areas such as: mitigation of voltage flicker and improving power factor.

• 한국기계가공학회지
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• 제19권4호
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• pp.24-29
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• 2020

Measuring the torque of the wheel loader of a driving device is a preemptive task to ensure its performance. In this study, wireless torque measurements were successfully conducted. Moreover, based on the experimental results and the adopted design method, the key factor of torque generation, which is the main load in driving devices, was analyzed. Other data not analyzed in this paper will be the basis for the logical design of wheel loader-based driving devices.

• 대한기계학회논문집A
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• 제24권9호
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• pp.2220-2227
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• 2000

In this paper, dynamic photoelastic hybrid method is developed and its validity is certified. The dynamic photoelastic hybrid method can be used on the obtaining of dynamic stress intensity factors and dynamic stress components. The effect of crack length on the dynamic stress intensity factors is less than those on the static stress intensity factors. When structures are under the dynamic mixed mode load, dynamic stress intensity factor of mode I is almost produced. Dynamic loading device manufactured in this research can be used on the research of dynamic behavior when mechanical resonance is produced and when crack is propagated with the constant velocity.

• JSTS:Journal of Semiconductor Technology and Science
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• 제11권4호
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• pp.272-277
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• 2011

The ambipolar behavior of tunneling field-effect transistors (TFETs) has been investigated quantitatively by introducing a novel parameter: ambipolarity factor (${\nu}$). It has been found that the malfunction of TFET can result from the ambipolar state which is not on- or off- state. Therefore, the effect of ambipolar behavior on the device performance should be parameterized quantitatively, and this has been successfully evaluated as a function of device structure, gate oxide thickness, supply voltage, drain doping concentration and body doping concentration by using ${\nu}$.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1998년도 Proceedings ICPE 98 1998 International Conference on Power Electronics
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• pp.506-511
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• 1998

This paper gives and analytical expression of the average and rms currents of switching devices in volt-age-fed PWM inverters. It is shown that the device currents are represented by a function of the power factor of the load and the normalized output voltage of the inverter. The validity of the derived formulas is confirmed with simulation and experiment, showing that the modulation method has a minor effect on the characteristics of the device current.

• 한국전자통신학회논문지
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• 제13권4호
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• pp.745-750
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• 2018

WLAN 통신 기술 적용을 위한 위상 반전 장치를 갖는 슬롯 배열 안테나가 제안되었다. 제안된 안테나 설계를 위해 배열 안테나의 Array Factor와 방사 특성을 분석하였고 실질적인 적용이 가능한 방사 패턴을 위해, 위상 반전 장치를 사용하였다. 제안된 안테나는 $30mm{\times}96mm{\times}0.2mm$의 유전 기판의 양면에 구현되었다. 제안된 안테나의 측정 결과, 임피던스 대역폭은 156 MHz (2.392-2.548 GHz)이고, 최대 이득은 8.31 dBi이다.

• 한국산학기술학회논문지
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• 제14권1호
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• pp.13-19
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• 2013

국내 승용차용 삼원촉매의 경우 열적 내구성을 만족시키지 못하고 조기 파손되는 사례가 증가하고 있다. 이것은 차량의 배기가스 정화장치의 신뢰성에 치명적 손상을 유발시키므로 삼원촉매의 내구성 평가 모델을 파악할 필요가 있다. 따라서 본 연구에서는 세라믹 모노리스 담체에서 발생되는 열응력을 구한 뒤 강도저하계수모델과 파손확률을 기초로 삼원촉매의 열적 내구성을 평가하였다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제6권3호
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• pp.652-669
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• 2014

This paper concerns the kinematic characteristics of a coupling device in a deep-seabed mining system. This coupling device connects the buffer system and the flexible pipe. The motion of the buffer system, flexible pipe and mining robot are affected by the coupling device. So the coupling device should be considered as a major factor when this device is designed. Therefore, we find a stable kinematic device, and apply it to the design coupling device through this study. The kinematic characteristics of the coupling device are analyzed by multi-body dynamics simulation method, and finite element method. The dynamic analysis model was built in the commercial software DAFUL. The Fluid Structure Interaction (FSI) method is applied to build the deep-seabed environment. Hydrodynamic force and moment are applied in the dynamic model for the FSI method. The loads and deformation of flexible pipe are estimated for analysis results of the kinematic characteristics.