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Pt/TiO<sub>2</sub> 촉매의 물리화학적 특성이 CO 상온산화 반응에 미치는 영향 연구
김성철 ( Sung Chul Kim ),김거종 ( Geo Jong Kim ),홍성창 ( Sung Chang Hong ) 한국공업화학회 2018 공업화학 Vol.29 No.6
본 연구에서는, Pt/TiO<sub>2</sub> 촉매의 물리화학적 특성이 CO 상온산화 반응에 미치는 영향을 조사하기 위하여 각기 다른 물리적 특성을 가지는 다양한 TiO<sub>2</sub> 지지체를 이용하여 Pt/TiO<sub>2</sub> 촉매를 제조한 후 평가하였다. 촉매의 물리화학적 특성을 조사하기 위하여 XPS, CO-chemisorption, BET, CO-TPD 분석을 수행하였다. 그 결과, active particle diameter가 작을 수록, metal dispersion, surface area가 클수록 우수한 CO 상온산화 반응을 나타내었다. 이러한 물리적 특성은 active site의 수를 증진시켜 대상물질은 CO의 흡착량의 증가를 야기시켰다. 또한, O<sub>2</sub>-consumption이 클수록 우수한 산소 전달 능력을 통해 보다 높은 CO 상온산화 반응활성을 나타내었다. In this study, the effect of Pt/TiO<sub>2</sub> catalysts on the CO oxidation reaction at room temperature was investigated using various TiO<sub>2</sub> supports with different physical properties to compare and evaluate Pt/TiO<sub>2</sub> catalysts. Physicochemical properties of the catalyst were alanyzed using XPS, CO-chemisorption, BET, and CO-TPD. As a result, when the active particle diameter was smaller, while the metal dispersion and surface area were larger, the CO room temperature oxidation reaction was better. These physical properties increased the number of active sites, causing the target material to increase the adsorption amount of CO. In addition, when the O<sub>2</sub>-consumption increased, the CO-room temperature oxidation reaction activity increased due to the excellent oxygen-transferring ability.
Design Considerations for Low Voltage Claw Pole Type Integrated Starter Generator (ISG) Systems
Lee, Geun-Ho,Choi, Geo-Seung,Choi, Woong-Chul The Korean Institute of Power Electronics 2011 JOURNAL OF POWER ELECTRONICS Vol.11 No.4
Due to the need for improved fuel consumption and the trend towards increasing the electrical content in automobiles, integrated starter generator (ISG) systems are being considered by the automotive industry. In this paper, in order to change the conventional generator of a vehicle, a belt driven integrated starter generator is considered. The overall ISG system, the design considerations for the claw pole type AC electric machine and a low voltage very high current power stage implementation are discussed. Test data on the low voltage claw pole type machine is presented, and a large current voltage source DC/AC inverter suitable for low voltage integrated starter generator operation is also presented. A metal based PCB (Printed Circuit Board) power unit to attach the 4-parallel MOS-FETs is used to achieve extremely high current capability. Furthermore, issues related to the torque assistance during vehicle acceleration and the generation/regeneration characteristics are discussed. A prototype with the capability of up to 1000 A and 27 V is designed and built to validate the kilo-amp inverter.
손미아 ( Mia Son ),전거송 ( Geo-song Jeon ),배동철 ( Dong-chul Bae ),손병창 ( Byungchang Son ),김태운 ( Taeun Kim ),윤재원 ( Jae-won Yun ) 한국산업보건학회 (구 한국산업위생학회) 2021 한국산업보건학회지 Vol.31 No.2
Objectives: To investigate the trends of industrial injuries among long-term health care workers in Korea Methods: T7866 injuries were selected from the total industrial injuries approved by the Industrial Accident Compensation Insurance Act(Occupational Safety and Health Act) among long-term health care workers between 2007 and 2016 in Korea. We analyzied the trends of industrial injuries according to work process, occurrence type, and causes. Results: The industrial injuries among long-term health care workers increased since 2012. The mostly occurred area for industrial injuries were low back areas, which is related that the most serious industrial injuries occurred when the one long-term healthcare worker lift manually the recipient, from bed(ondol, Korean floor heating system) to a wheelchair, bed to bath bed, and wheelchair to bath chair. In addition to this, lack of workforce, increased work intensity due to overwork contributed the increasing of occupational injury. Conclusions: This study suggests that the main causes of industrial injuries were Lack of facilities and equipment for small private long-term care institutions, The physical load that goes into lifting the recipient directly, work intensity such as excessive workload and increased work speed. We suggest that the social publicization of long-term care service for the elderly, avoiding ways to lift recipients directly, introducing lifting machines as well as improving working methods, and reducing the workload of caregivers are required.
Effect of Material Characteristics on PMDC Motors based on the Grade of Electrical Steel Sheet
Jun-Young Kim,Dong-Woo Kang,Tae-Chul Jeong,Hyun-Soo Seol,Han Kim,Geo-Chul Jeong,Myung-Sik Jeong,Huai-Cong Liu,Ju Lee 한국자기학회 2019 Journal of Magnetics Vol.24 No.2
In this study, the effect of the material characteristics of electrical steel sheet on permanent magnet direct current (PMDC) motors is investigated using finite-element analysis. The motor design and test results are examined and verified through fabrication. The characterizations of brushless direct current (BLDC) motors according to the materials used in their cores have been actively studied. On the other hand, the effect of material characteristics on a PMDC motor consisting of brushes and commutators has not been studied as much. In the case of the PMDC motors, electrical steel sheets are infrequently used because this motor is relatively smaller than the BLDC motor. However, the iron loss characteristics, which are proportional to the frequency and the magnetic flux density, affect the efficiency even in small motors. Further, the output of the motor changes owing to saturation due to iron loss. The outcome presented in this study provides core materials selection guidelines to improve motor efficiency.
자기부상 운송시스템 추진용 선형 유도 전동기의 설계 파라미터 분석
지우영(Woo-Young Ji),정거철(Geo-Chul Jung),박찬배(Chan-Bae Park),이형우(Hyung-Woo Lee) 한국철도학회 2017 한국철도학회 학술발표대회논문집 Vol.2017 No.05
선형 유도 전동기(Linear Induction Motor, LIM)는 1차측에서 발생시킨 이동 자속과 2차측에 유도된 와전류의 전자기적 상호작용으로 발생하는 로렌츠 힘을 이용하여 추진하는 방식이다. 1차측의 코어와 2차측의 도체판의 형상에 따라 자속의 흐름이 바뀌고 유도되는 와전류 또한 변하기 때문에 LIM의 성능 특성이 달라진다. 본 논문은 LIM의 추력, 추력리플, 효율, 역률을 반응변수로 설정하고 이에 영향을 미치는 주요 설계변수를 설정하였다. 유한요소 법과 반응 표면법을 사용하여 주요 설계 변수에 따른 반응변수 변화를 분석하였고 목적함수 값을 만족하는 최적 모델을 도출하였다. In this study, the analysis of design parameters of linear induction motor was conducted. Linear induction motor is propelled by Lorentz force generated by electromagnetic interaction between magnetic flux and current. The primary makes moving magnetic flux and eddy current is induced in the secondary plate. Therefore, performances of the LIM such as thrust force, ripple, efficiency is changed as shape of the primary and the secondary vary. This paper presents the analysis of the effects of design parameters by using Finite Elements Method (FEM). And derive the optimal model that satisfy the required thrust force, low ripple, high efficiency and power factor by using Response Surface Method (RSM).