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평면 다수 입출력 전력 분배/결합회로의 2 GHz에서의 구조 수정 연구
한용인,조치성,김인석 한국항행학회 2002 韓國航行學會論文誌 Vol.6 No.4
본 논문에서는 하나의 입력과 다수의 출력을 가지는 [10]에서에서 제시한 평면 Taper 형의 전력 분배/결합기를 2GHz대역에서 수정한 구조를 제안한다. 제안하는ㄱ n조의 전기적 특성을 결정하는 파라메터들을 HFSS시뮬레이션을 이용하여 분석하였다. 입력 정합 그리고 각 출력 단에서 출력 신호의 균형과 위상의 선형성을 위해 회로의중앙에 하나의 원형 모양을 애칭 제거하였다. 또 본 논문에서 제안한 구조의 1:2와 1:3의 전력 분배/결합기외 [10]의 구조와 S-Parameter를 비교?분석하였다. 결과적으로 본 연구에서 제시하는 수정된 형태를 적용할 경우 기존의 전력 분배/결합기의 반사손실 특성이 2 GHz에서 20dB이상 개선되었고 대역폭 또한 증가되는 것을 확인하였다. In this paper, tapered shape of multiport power divider/combiner modified for 2 GHz range from the model published by [10] is proposed. Parameters determining electrical property of the circuit structure have been analyzed by HFSS simulation. For input matching, balance of output signals and phase linearity at each output port, one circular hole has been etched out on the circuit surface. 1:2 and 1:3 power dividers/combiners designed by this study have been compared with the same circuits designed by the method of [10] in terms of S-parameters. As a result, it has been found that the modified structure of power divider/combiner have improved return loss more than 20 dB and another 18 dB, respectively, at 2 GHz.
고립성 폐결절의 조직학적 진단에 있어서 경기관지폐생검의 진단적 가치
김치훈,김정주,왕준호,연규민,김형수,리원연,용석중,신계철 건국대학교 의과학연구소 2002 건국의과학학술지 Vol.12 No.-
Transbronchial lung biopsy(TBLB) is a relatively simple and convenient diagnostic tool in solitary pulmonary nodule(SPN) on chest radiograph, which is cannot be diagnosed through routine tests. To investigate the diagnostic value and diagnostic rate of TBLB according to the variable factor, we analyzed 69 patients with radiologically SPN lesion on chest radiograph which was confirmed histologically. A histologic diagnosis of TBLB was made in 47 of 69 patients(68.1%), in which 26 of 37(70.3%) with malignancy and 21 of 32(65.6%) with benign lesion. There were no significant differences in diagnostic yield according to age, sex and location of the lesion. The diagnostic rate tended to increase with the more than 5 pieces to acquired by TBLB. When the size of SPN was less than 3 ㎝, it cannot be diagnosed. In conclusion, TBLB is a diagnostic procedure with good yield and safety, but percutaneous needle aspiration, transbronchial needle aspiration, and bronchial washing fluid cytology may be a complementary procedure to overcome the limitation of TBLB and get higher diagnostic yield for SPN.
김치엽,최만용,권일범,이승석 한국비파괴검사학회 2003 학술대회 논문집 Vol.- No.1
Structural health monitoring system should developed to be based on internet and database technology in order to manage efficiently large structures. This system is operated by internet connected with the side of structures. The monitoring system has some functions: self monitoring, self diagnosis, and self control etc. Self monitoring is the function of sensor fault detection. If some sensors are not normally worked, then this system can detect the fault sensors. Also Self diagnosis function repair the abnormal condition of sensors. And self control is the repair function of the monitoring system. Especially, the monitoring system can identify the replacement of sensors. For further study, the real application test will be performed to check some unconvinrences.
토끼에서 Etofenprox와 Spinosad 합제의 국소자극성 시험
황윤환,김명석,송인배,박병권,양승호,임용현,송치용,안성한,남현수,임정교,정상일,명노일,윤효인 忠南大學校 獸醫科大學 附設 動物醫科學硏究所 2008 動物醫科學硏究誌 Vol.15 No.1
This study was performed to evaluation the skin and eye irritation of etofenprox 8% and spinosad 4% combination in male New Zealand White rabbits. In skin irritation test, the combination of etofenprox and spinosad did not showed any change of body weight but caused slight skin irritation with the P.I.I. (primary irritation index) value 0.25. The etofenprox and spinosad combination showed severe eye irritation 1 h, 24 h, 48 h, and 72 h after ocular treatment, having the A.O.I. (acute ocular irritation) value of 37.3. Therefore, these result indicated that the combination of etofenprox and spinosad might be irritant formulation on eye and skin.
요부 외측구역 협착증에서 단순감압술과 기구고정술을 병행한 요추체간 골유합술과의 임상적 비교
손병길,최은석,정을수,신종현,김명진,지용철 대한척추신경외과학회 2004 Neurospine Vol.1 No.1
Objective: The lumbar spinal canal can be devided into the central zone and the lateral zone. The divisions of the lateral zone are the subarticular, the foraminal, and the extraforaminal zone. A common causes of the operation for the spinal stenosis are related to the association with the spondylolisthesis and the central stenosis. There is a paucity of data, however, regarding the operative intervention in the lateral zone stenosis(LZS). Our aim was to analyze the surgical result by the anatomical type and the operative method. Methods: 72 patients of LZS excepting the association with the spondyolisthesis have been operated by six neurosurgeons of our hospital from 30th April, 1994 through 30th September, 2002. The patients had been interviewed about surgical result through telephone by third party persons. The surgical results were analyzed by the four score rating system: ① medication, ② ADL(Ability of daily living), ③ the degree of improvement, ④ the degree of satisfaction. Results: Among 72 patients, there were 25 males and 47 females. The age group of the patients were in their thirties(1), forties(9), fifties(21), sixties(36) and seventies(5). Surgical methods were used on decompression(22), posterior lumbar interbody fusion(PLIF) with cage(1) and PLIF with transpedicular screw fixation system(49). The types of stenosis were subarticular(24), foraminal(16) and extraforaminal(30) and double crush(2). The overall surgical results were Excellent(18), Good(34), Fair(19), and Poor(1). The Non-success rate according to the methods of surgery were decompression(34.8%), PLIF with transpedicular fixation system(24.4%). The overall success rate was(53/72: 73.6%). The success rate according to the types were subarticular(17/24: 70.8%), extraforaminal(21/30: 70%), and foraminal(12/16: 75%). Conclusion: It is suggested that the result was more favorable on the cases of lateral zone stenosis operated with PLIF and transpedicular fixation system. According to the method used, the success rate of decompression was worse than PLIF with transpedicular fixation system.
Numerical study on the range enhancement of a centrifugal compressor with a ring groove system
Chi-Yong Park,Young-Seok Choi,Kyoung-Yong Lee,윤준용 대한기계학회 2012 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.26 No.5
A numerical study of casing treatments on a centrifugal compressor to improve stability and stall margin is presented. High efficiency,high pressure ratio, and a wide operating range are required for a high-performance centrifugal compressor. A ring groove casing treatment is effective for flow range enhancement in centrifugal compressors. Compressor performance was analyzed according to the ring groove location, and the results were compared with the case without a ring groove. The effect of guide vanes in the ring groove was also investigated. Four variants of grooves were modeled and simulated using computational fluid dynamics to optimize the groove location. Numerical analysis was performed using a commercial code ANSYS-CFX program. The simulation results showed that the ring groove increased the operating range of the compressor. The ring groove with guide vanes improved both performance of the compressor at low flow rates and the stall margin of the compressor.