http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
누설변압기 1차측의 스위칭 제어에 의한 펄스형 $CO_2$레이저에 관한 연구
정현주,이동훈,김희제,Chung, Hyeon-Ju,Lee, Dong-Hoon,Kim, Hee-Je 대한전기학회 2000 전기학회논문지C Vol.52 No.10
We propose a pulsed $CO_2$laser below 30W by the AC(60Hz) switching control of leakage transformer primary which has some advantages of cost and size compared to a typical pulsed power supply. Pulse repetition rate is adjusted from 5 Hz to 60 to Hz control laser output. In this laser a low voltage open loop control for high voltage pulse discharge circuit is employed to aviod the Hv sampling or switching and high voltage leakage transformer is used to convert low voltage pulse rectified from AC to high voltage one. A ZCS(Zero Crossing Switch) circuit and a PIC(programble one-chip microprocessor are used to control gate signal of SCR precisely. The pulse repetition rate is limited by 60Hz due to the frequency of AC line and a high leadkage inductance. The maximum laser output was about 23 W at pulse repetition rate of 60Hz total gas mixture of $CO_2$ : $N_2$ : He=1: 9: 15 and total pressure of 18 Torr
양창섭,정현주,신승제,Yang, Chang-Seob,Chung, Hyun-Ju,Shin, Seung-Je 한국군사과학기술학회 2006 한국군사과학기술학회지 Vol.9 No.2
The underwater electromagnetic signatures of a naval ship are mainly generated from three sources which are the permanent and induced magnetic field in the ship's hull and other ferrous components, the cathodic current electromagnetic field established by the Impressed Current Cathodic Protection(ICCP) system or the Sacrificial Anode and the stray electromagnetic fields generated by onboard equipment. These signatures can be minimized by certain design methods or installation of signature reduction equipment. In this paper, we represented the characteristic of the underwater electromagnetic signature and the signature reduction techniques for a naval ship. Also, we measured the electromagnetic field changes emitted from the real ship using the Electric and Magnetic field Measurement System(EMMS). We found that the underwater electromagnetic signature for a naval ship can be used as input or trigger signal in a surveillance system and an influence mine.
이동훈,임규호,정현주,김희제,조정수,Lee, Dong-Hoon,Im, Kyu-Ho,Jeong, Hyun-Ju,Kim, Hee-Je,Jo, Jung-Soo 대한전기학회 1999 전기학회논문지C Vol.48 No.8
In this study, it is the purpose to develope a cheap and compact $CO_2$ laser and to apply 60 Hz AC discharges as a new exciting source. An axial and water cooledtype was adopted as the laser mode. The laser performance characteristics as various parameters, such as gas pressure and discharge current, have been investigated. And the laser output and the efficiency of DC and 60 Hz AC discharge-exciting type have been measured and compared for the different input powers at the static operational pressure. As a result, the case of 60 Hz AC discharge-exciting type, the laser oscillation began at the condition of operational pressure 6 Torr and discharge current 5 mA. A maximum laser output of about 32 W was obtained at an operational pressure of 18 Toorr and a discharge current of 30 mA. In addition, the laser output was saturated from an operational pressure of about 14 Torr and a discharge current of about 20 mA. In this $CO_2$ laser, the laser output of 60 Hz AC discharge-exciting type was slightly higher than that of DC discharge-exciting type. And the laser efficiency was about 10 to 13% for the various operational pressures and the discharge currents.
정지비행시 헬리콥터 로터 블레이드의 공력해석 및 최적화
제상언(S.E. Je),정현주(H.J. Jung),김도준(D.J. Kim),조창열(C.Y. Joh),명노신(R.S. Myong),박찬우(C.W. Park),조태환(T.H. Cho) 한국전산유체공학회 2007 한국전산유체공학회 학술대회논문집 Vol.2007 No.-
In this paper a method for the design optimization for helicopter rotor blade in hover is studied. Numerical analysis of aerodynamic characteristics of the flow around a rotor blade is analysed by usign panel method and CFD code based on Navier-Stokes equation. The result is validated by comparing with existing experimental result. Optimization methods RSM(Response Surface Method) and DOE(Design of Experiments) are applied in combination. The object functions are power, twist angle, taper ratio, and thrust. The optimized result showed a decrease of 17% of the power required.