http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
인버터 구동 시스템에서의 EMI 저감을 위한 새로운 PWM 구현
함년근(Hahm Nyon Kun),김이훈(Kim Lee-Hun),전기영(Jun Ki-Young),천광수(Chun Kwang-Su),원충연(Won Chung-Yuen),한경희(Han Kyung-Hee) 전력전자학회 2004 전력전자학술대회 논문집 Vol.- No.-
High frequency common mode voltage produced by power inverters are a major cause of conducted EMI, creating motor ground currents, bearing currents and other harmful by products. This paper focuses on a new SVPWM method with random PWM injection to reduce conducted EMI noise. A New PWM technique associated with the common mode voltage can be significantly reducing and contributes to mitigate. The common mode voltage to 50% in comparison with that for conventional SVPWM technique. Validation of the theory and reduction methods are then performed experiment ally based on an induction motor drive.
Jang, Pill Gyu,Suh, Kwang S.,Park, Min,Kim, Jun Kyung,Kim, Woo Nyon,Gyu Yoon, Ho Wiley Subscription Services, Inc., A Wiley Company 2007 Journal of applied polymer science Vol.106 No.1
<P>We have studied the electrical conductivity and percolation threshold of polyurethane (PU) composites filled with multiwalled carbon nanotubes (MWCNT) purified by increasing immersion time in aqueous solutions of either nitric acid or a mixture of nitric and sulfuric acids at 80°C. The MWCNT crystallinity peaks after 2 h of treatment, which enables the PU composites to enhance the percolation threshold and electrical conductivity in the conductive network formation region. MWCNT treated under either a milder or severer acidic condition deteriorate the electrical behavior of the composites, since MWCNT are poorly dispersed in the PU matrix in the former condition, but lost their intrinsic electrical conductivity due to the partial destruction of their crystalline structure in the latter. Therefore, the acid treatment needs to be carefully controlled to effectively purify the MWCNT, maintain the crystalline structure without further damage, and thereby improve the electrical behavior of PU/MWCNT composites. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007</P>
金鍾禹,羅光淵 忠南大學校 1974 論文集 Vol.13 No.1
These studies were conducted to find out the preparation of milk-clotting enzyme from the stomach of dairy goat, have widely raised in Korea, and it's properties. The effects of various extracting conditions from the stomach of kid on the milk-clotting activity, keeping quality and utility for cheese-making of the enzyme preparations were determined, and the results obtained were as follows. 1) Milk-clotting activities of the enzyme preparations extracted from 1∼3 weeks aged kids were stronger than these from 4 or more weeks aged kids. 2) When the enzyme preparation were extracted with 5% NaCl solution for 10 days, the milk-clotting activities were increased for their extracting time up to 10 days and their increasing rate was gradually show after 3 days. 3) The most effective pH value for the extraction of the enzyme was pH 5.0. 4) Potassium sorbate was more effective than boric acid as a antiseptics for the extraction of the enzyme. 5) Calcium chloride solution was the most effective salts for the extraction of the enzyme, and potassium chloride soluton. 6) When the enzyme preparations were stored at various temperatures and times, the higher temperature and the longer times were treated, the less milk-clotting activities were remained. 7) The addition of lactose or starch to the enzyme preparation was not effective to the maintenance of milk-clotting activity. 8) Milk-clotting activity of the enzyme preparation was completely disappeared by the treatments at 65℃ or more for 10 minutes. 9) When the enzyme preparation were exposed to the sunlight for 10 hours, the milk clotting activities of those contained in colorless and brown bottles were decreased to 34 and 23% respectively compared to those stored at dark and chilling room. 10) The yield and quality of Gouda cheese made with the kid rennet were superier to that with calf rennet powder.
양원호 ( Won Ho Yang ),김치년 ( Chi Nyon Kim ),김태형 ( Tae Hyeung Kim ),노영만 ( Young Man Roh ),심상효 ( Sang Hyo Sim ),원정일 ( Jung Il Won ),이채관 ( Chae Kwan Lee ),정광호 ( Kwang Ho Chung ),정지연 ( Jee Yeon Jeong ),조기홍 ( 한국산업위생학회 2013 한국산업보건학회지 Vol.23 No.2
Objectives: This study was performed in order to investigate by questionnaire the factors affecting the occupational satisfaction of work-environment measurement workers, as well as to suggest fundamental materials for systematic, administrative and economic improvements which are necessary to create a vision for the future. Material and Methods: A structured questionnaire was used at a total of 152 institutions and 1,254 work-environment measurement workers throughout the country from February to September 2012. Responses came from 97 institutions (64%) and 941 work-environment measurement workers (75.1%). The factors affecting the job satisfaction of work-environment measurement workers were statistically evaluated through χ 2 -test and ordinal logistic regression analysis. Results: Major factors affecting the job satisfaction of workers in relation to work-environment measurement were working, financial, and psychological conditions (p<0.05). Conclusions: Considering the results of this study, the improvement of labor conditions should be undertaken because workers engaged in work-environment measurement are fundamental to occupational health.
Kweon Hyung Han(한권형),Seung Hwan Lee(이승환),Tae Seok Kim(김태석),Kwang Ho Song(송광호),Chong Min Koo(구종민),Woo Nyon Kim(김우년) 한국고분자학회 2021 폴리머 Vol.45 No.2
폴리프로필렌(polypropylene, PP)/탄소섬유 복합재료의 반사손실(reflection loss, RL)과 임피던스 매칭(impedance matching) 특성을 두 가지 다른 방법으로 제조된 PP/탄소섬유 복합재료에 관하여 연구하였다. 탄소섬유 함량을 10wt% 첨가하여 사출성형 가공방법으로 제조된 PP/탄소섬유 복합재료의 RL 값은 -29.1 dB로 나타났고, 같은 탄소섬유 함량을 첨가하여 압출성형 가공방법으로 제조된 PP/탄소섬유 복합재료의 RL 값은 -15.6 dB로 나타났다. 이와 같이 사출성형 방법을 이용하여 제조된 PP/탄소섬유 복합재료의 우수한 RL 특성은 제조된 복합재료의 임피던스 매칭 특성으로 인한 것으로서 이는 사출성형 방법으로 제조된 PP/탄소섬유 복합재료의 섬유길이가 압출성형 방법으로 제조된 복합재료의 섬유길이보다 더 길어서 발생하는 것으로 사료된다. 이상의 결과로부터 효과적인 전자파 흡수 PP/탄소섬유 복합재료를 얻기 위해서는 제조된 복합재료의 섬유길이가 중요한 요인임을 알 수 있다. The reflection loss (RL) performance and impedance matching characteristics of polypropylene (PP)/carbon fiber composite were studied according to two different composite preparation methods. For the PP/carbon fiber composite prepared by injection molding process, the RL value of -29.1 dB was achieved at low carbon fiber content (10 wt%), compared with the composite prepared by screw extrusion process (-15.6 dB). This good RL performance of the PP/carbon fiber composite prepared by the injection molding process was attributed to the impedance matching characteristic originating from the longer fiber length in the composite, than in the composite prepared by screw extrusion. The results suggest that the carbon fiber length in the composite is an important factor to achieve PP/carbon fiber composites that have effective electromagnetic wave absorbing properties.
PWM 기법을 이용한 인버터-유도전동기 구동 시스템의 전도 노이즈 및 스위칭 소음 저감
박현석(Park Hyun-Seok),김이훈(Kim Lee-Hun),정정길(Jeong Jeong-Gil),천광수(Chun Kwang-Su),원충연(Won Chung-Yuen),함년근(Hahn Nyon-Kun),신한순(Shin Han-Soon) 전력전자학회 2003 전력전자학술대회 논문집 Vol.2003 No.11
The random pulse width modulation(RPWM) on the noise and vibration abatement in inverter-fed induction motor drive is presented.<br/> This paper describes a RPWM technique based on space vector PWM strategy for shaping the switching noise spectrum in such a way it can merge with the natural system noise.<br/> To verify the validity of the proposed RPWM scheme, the experiment based on the TMS320 C31 microprocessor was executed.<br/> Finally, the simulation and experimental results will be given to demonstrate the effectiveness of the proposed RPWM technique.
대도시 대리운전 기사의 안전 운행에 영향을 주는 고객의 폭언 및 폭행 실태에 관한 연구
이준희 ( June Hee Lee ),원종욱 ( Jong Uk Won ),노재훈 ( Jae Hoon Roh ),김치년 ( Chi Nyon Kim ),석홍덕 ( Hong Deok Seok ),이완형 ( Wan Hyung Lee ),김영광 ( Yeong Kwang Kim ),황정호 ( Jung Ho Hwang ),윤진하 ( Jin Ha Yoon ) 한국산업보건학회 2015 한국산업보건학회지 Vol.25 No.3
Objectives: The purpose of this study was to research ‘Daeri’ drivers who work for drunken customers as a substitute driver. This was the first study in Korea to investigate assault and verbal abuse experienced while employed as a ‘Daeri’ driver. Methods: In this study, we conducted a survey to investigate people who work as ‘Daeri’ drivers. The survey was performed from September 1 to 7, 2014. The participants were 166 adult men and women who work as full-time ‘Daeri’ drivers. Results: Participants who experienced physical violence and assault from the customers to the point of disturbing safe driving in a year were 36.1% of total respondents. People who experienced verbal abuse to the point of disturbing safe driving in a year totaled 80.4% of respondents. In addition, there were also qualitative research results. Conclusions: Acts that impede safe driving are a danger to both passengers and drivers. By protecting the safety of ‘Daeri’ drivers, we will be able to protect the safety of citizens. Therefore, it is necessary to make an effort to protect ‘Daeri’ drivers from customer violence. Furthermore, it is also necessary to research policy to emplace a legal system that can protect ‘Daeri`` drivers