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무전극 램프 구동용 영전압 스위칭 고주파 인버터에 관한 연구
박동현,김희준,조기연,계문호,Park, Dong-Hyun,Kim, Hee-Jun,Joe, Kee-Yun,Kye, Mun-Ho 대한전자공학회 1998 電子工學會論文誌, S Vol.s35 No.8
무전극 램프의 점등은 램프 양단에 고주파를 갖는 고전압을 인가해야 한다. 종래의 무전극 램프의 구동 회로로 선형 증폭기가 이용되어져 왔으나, 낮은 에너지 변환 효율로 인해 PWM 스위칭 방식의 인버터로 교체되고 있다. 그러나 고주파 스위칭시 인버터의 스위칭 소자에서 스위칭 손실의 증가 및 노이즈 발생의 문제로 인해 PWM 인버터는 고주파 동작이 제한된다. 이러한 문제점을 해결하기 위해 영전압 스위칭 기술을 PWM 인버터에 적용하여 고주파 스위칭이 가능하게 하고, 또한 스위칭 손실과 노이즈 발생을 줄일 수 있다. 본 논문에서는 무전극 램프 구동회로로 영전압 스위칭 고주파 인버터에 대하여 동작 해석과 설계 지침 제시하였다. 또한, 실험을 통하여 해석된 결과의 타당성을 확인하였다. Driving the electrodeless fluorescent lamp, the high ac voltage with high frequency is required. The linear power amplifier has been widely used as a driving circuit of electrodeless fluorescent lamp. However, the low efficiency of the power amplifier causes the driving circuit to be replaced by a PWM switching inverter. In order to use a PWM switching inverter as the driving circuit to be replaced by a PWM switching inverter. In order to use a PWM switching inverter as the driving circuit of an electrodeless fluorescent lamp, the high switching frequency is required. But due to the switching loss at switches of the inverter, the limitation of high switching frequency appears in the inverter. One solution to this limitation is to reduce the switching loss by using the zero voltage switching technique. In this paper, zero voltage switching resonant inverter for driving an electrodeless fluorescent lamp is discussed. The results of analysis about the inverter are presented and the equations for design are established. And the validity of the analyzed results are verified through the experiment.
카드뮴이 뇌혈관 내피세포에서의 $PGE^2$ 및 COX-2 발현에 미치는 영향
박동현,김영채,문창규,정이숙,백은주,문창현,이수환,Park Dong-Hyun,Kim Young-Chae,Moon Chang-Kiu,Jung Yi-Sook,Baik Eun-Joo,Moon Chang-Hyun,Lee Soo-Hwan 환경독성보건학회 2006 환경독성보건학회지 Vol.21 No.3
In order to get insight into the mechanism of cadmium (Cd)-induced brain injury, we investigated the effects of Cd on the induction of COX-2 in bEnd.3 mouse brain endothelial cells. Cd induced COX-2 expression and $PGE_2$ release, which were attenuated by thiol-reducing antioxidant N-acetylcysteine (NAC) indicating oxidative components might contribute to these events. Indeed, Cd increased cellular reactive oxygen species (ROS) level and DNA binding activity of nuclear factor-kB (NF-kB), an oxidative stress sensitive transcription factor. Cd-induced $PGE_2$ production and COX-2 expression were significantly attenuated by Bay 11 7082, a specific inhibitor of NF-kB and by SB203580, a specific inhibitor of p38 mitogen activated protein kinase (MAPK). These data suggest that Cd induces COX-2 expression through activation of NF-kB and p38 MAPK, the oxidative stress-sensitive signaling molecules, in brain endothelial cells.
N - 포밀 아스파르테임의 산화 탈포밀 반응에 의한 아스파르테임의 제조 방법
박동현,이윤식 ( Dong Hyun Park,Yoon Sik Lee ) 한국공업화학회 1990 공업화학 Vol.1 No.1
For-α-APM을 For-Asp anhydride와 Phe-OMe를 MEK, CH_3CN, 물 등의 용매를 사용하여 반응시켜 효율적으로 합성하였다. For-α-APM과 For-β-APM의 혼합물로부터 순수한 For-α-APM의 회수는 pH 4.00에서의 연속적인 분별추출로 분리 수거가 가능하였다. H_2O_2/HCl/MeOH등의 다양한 산화계를 사용하여, H_2O_2에 의한 산화방법으로 탈포밀반응을 성공적으로 수행하여 높은 수율로 아스파르테임을 얻을 수 있었다. 이때, HCl이나 TsOH와 같은 산이 H_2O_2의 분해를 억제시키고 산화능을 증대시킴으로써 탈포밀 반응의 효율을 높일 수 있었다. For-α-APM was efficiently prepared by the reaction of For-Asp anhydride and Phe-OMe in methylethylketone, CH_3CN, and in water. The selective recovery of For-α-APM from the resulting For-α-APM and For-β-APM mixture was possible via repetitive extraction at constant pH of 4.00. The oxidative deformylation was successfully performed by using several oxidants including H_2O_2/THF, sodium percarbonate, and H_2O_2/HCl/MeOH giving APM in high yields. The efficiency of the oxidative deformylation was raised in acidic condition for all the deformylation reactions.
음력(陰曆)을 양력(陽曆)으로 환산(換算)하는 간편(簡便)한 방법(方法) - 고려(高麗) 이조(李朝) 천문(天文) 연구(硏究) 1 -
박동현,Park, Dong-Hyun 한국천문학회 1968 Journal of The Korean Astronomical Society Vol.1 No.1
A simple method for solar-lunar calendar conversion is obtained by means of Meton period for the convinience of the date conversion in the study of the old records of astronomical observations in Korea.
박동현,명노해,Park, Dong-Hyun,Myung, Ro-Hae 대한인간공학회 2005 大韓人間工學會誌 Vol.24 No.3
Little research has been performed regarding auditory icons even though auditory icons have great potentials as a strategy for creating informative, intuitively accessible, and unobtrusive interface. Therefore, this study was conducted to design new auditory icons through the iconic mapping for ten most frequently used mobile phone menus, and to show the usability of auditory icons. Two most familiar auditory sounds for each menu were collected and compared to the current button-pressing sound. The results show that the newly designed auditory icons had shorter recognition times, better satisfaction than the current icons. In other words, auditory icons could be an effective interface to provide a redundant feedback along with visual feedbacks in navigating mobile devices.