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2.4GHz대역 ZigBee 송수신기를 사용한 과학화 전투훈련 시스템에서 최소송신전력과 간섭에 관한 연구
곽현상,유호준,김영호,전상현,김종헌,이찬주,임승찬,Kwak, Hyun-Sang,Yoo, Ho-Joon,Kim, Young-Ho,Chun, Sang-Hyun,Kim, Jong-Heon,Lee, Chan-Joo,Lim, Seung-Chan 한국군사과학기술학회 2008 한국군사과학기술학회지 Vol.11 No.6
In this paper, interference analysis has been performed between RF receiver and transmitters on each soldier for Multiple Integrated Laser Engagement System(MILES) which are following ZigBee standard. In order to obtain minimum transmit power without interference, 1% Packet Error Rates(PER) from 14 transmitters attached on a soldier to a receiver are measured with the scenarios for simple transmitting and receiving network configuration and for repeating network configuration. Based on this transmit power, the available distance for interference free among soldiers is simulated using Spectrum Engineering Advanced Monte Carlo Analysis Tool(SEAMCAT). Later scenario gives the benefit of 10dB lower transmit power, smaller and lighter power source, and better activity of trainee.
플라즈마 응용을 위한 선택적 감쇠기를 사용한 고안정 고효율 전력증폭기
김지연(Ji Yeon Kim),이동헌(Dong Heon Lee),전상현(Sang Hyun Chun),유호준(Ho Joon Yoo),김종헌(Jong Heon Kim) 한국전자파학회 2009 한국전자파학회논문지 Vol.20 No.1
본 논문에서는 플라즈마 응용을 위한 고효율 및 고안정성을 가지는 RF 발생기용 1 ㎾급 전력증폭기를 설계 및 제작하였다. 전력증폭기는 푸쉬풀 MOSFET 1개와 고전류 구동 IC로 구성하였으며, E급 증폭기의 구조를 사용함으로써 효율을 개선하였다. 플라즈마 응용에 적합하도록 전력증폭기에 선택적 감쇠기를 사용하여 3가지 모드로 동작하게 함으로써 효율과 안정성을 선택적으로 고려할 수 있도록 하였다. 초기 방전 구간의 불안정성을 개선하기 위하여 RF 발생기의 출력 안정영역을 선택적 감쇠기를 사용하여 전압정재파비(VSWR)를 3.8:1미만보다 개선된 4.5:1미만으로 확장하였다. 또한 기존에 적용되는 증폭기에 비하여 크기를 30 % 줄였으며, 주파수 13.56 ㎒, 출력 1 ㎾에서 효율 80 %를 얻으므로 기존에 비하여 효율을 약 13 % 개선하였다. In this paper, a new 1 ㎾ power amplifier with high efficiency and high stability in a RF generator is designed and fabricated for plasma applications. The efficiency of power amplifier is improved by using class-E amplifier that consists of one push-pull MOSFET and high current drive IC instead of class-C amplifier composed of several single ended MOSFET. Switchable damper that allows selecting three different modes of amplifiers for considering efficiency and stability is added into the amplifier for plasma applications. Stable region of an early electronic discharge section is extended to VSWR of 4.5:1 compared to conventional VSWR of 3.8:1 through using switchable damper. The dimension of the amplifier is also reduced to 30 % of conventional amplifier. The 80 % efficiency of power amplifier with switchable damper is obtained the output power of 1 ㎾ in operating frequency of 13.56 ㎒. In comparison of conventional power amplifier for plasma applications, 13 % efficiency is improved.
임인서(In Seo Lim),이건웅(Gun Young Lee),전상현(Sang Hyun Chun),김근호(Gheun Ho Kim),구자룡(Ja Ryong Goo),전노원(Rho Won Chun),채동완(Dong Wan Chae),김형직(Hyung Jik Kim),노정우(Jung Woo Noe) 대한내과학회 1995 대한내과학회지 Vol.49 No.5
N/A Objectives: Several factors have been raised as contributing to morbidity and mortality among patients with end-stage renal disease treated with hemodialysis. We performed this study to evaluate morbidity and the factors contributing to them in chronic hemodialysis patients. Methods. We analyzed retrospectively the demo- graphic chracteristics, regularly tested laboratory findings (CBC, blood chemistry, chest X-ray, ECG), hospitalization rate, and gross mortality among 84patients in the Hallym University Medical Center from February I, 1992 to January 31, 1994. Results: 1) Age distribution of the patients was 54±13(mean±SD) years (range, 23-79 years); 41 patients were men, 43patients were women: 30patients(35.7%) had diabetes. The duration of hemodialysis was 33±30 months (range, 3-125 months). 2) Forty four patieints(52.4%) required hospitalization during the 2-year follow-up period, and the most common causes of hospitalization were infection and cardiovascular disease. 3) A total of 1H(21.4%) of the patients died the 2-year follow-up period, and cardiovascular disease was commonest cause of death. 4) The factors such as advancing age, the duration of hemodialysis, and diabetes were neither associated with the risk hospitalization nor with that of death. The serum albumin concentration in dead patients(3.4±0.4g/d1) was lower(p<0.001) than that in survived patients(3.8±0.4g/dL). As compared with patients who had serum albumin concentration ≥3.5g/dL, patients with serum albumin concentration <3.5g/dL had increased odds ratio(8.14) for death. The serum creatinine concentration in dead patients (9.5+3.0g/dL) was lower(p<0.%! than that in survived patients(11.8±3.1g/dL). Conclusion: We concluded that regularly tested serum albumin concentration was the most important predictive factor for death in chronic hemodialysis patients.