• Journal of the Korean Society for Precision Engineering
• /
• v.25 no.4
• /
• pp.53-60
• /
• 2008

Electron detectors used in scanning electron microscope accept electrons emitted from the specimen and convert them to an electrical signal that, after amplification, is used to modulate the gray-level intensities on a cathode ray tube, producing an image of the specimen. Electron detector is one of the key components dominating the performance of scanning electron microscope so that the development of electron detectors having high performance is indispensable to acquire high quality images using scanning electron microscope. In this paper, we designed and manufactured an electron detector and conducted a couple of image capture experiments using it. In particular, scintillator which generates light photons when it is struck by high-energy electrons was manufactured and experimental studies on the optimization of manufacturing condition was carried out. From experiments to evaluate the performance of our detector, it was verified that the performance of our detector is equivalent to or better than that of the conventional one.

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.8 no.2
• /
• pp.41-44
• /
• 1971

• Electrical & Electronic Materials
• /
• v.12 no.2
• /
• pp.19-23
• /
• 1999

• Journal of the Korean Institute of Telematics and Electronics
• /
• v.2 no.2
• /
• pp.17-22
• /
• 1965

• Proceedings of the IEEK Conference
• /
• 2003.11a
• /
• pp.107-110
• /
• 2003

본 논문은 LTJ 적응필터의 실용적 구현에 관한 연구이다. 음성코덱(codec)을 사용하는 응용분야에서는 코덱 복호화단의 LPC 계수정보를 얻을 수 있으므로 이를 반사계수로 변환하여 사용하므로서 반사계수 적응에 소용되는 계산량을 감소시킬 수 있으며, 코덱에서는 프레임 또는 서브프레임 단위로 LPC 계수를 적응시키므로 시변 변환 영역 적응필터에 해당하는 LTJ 적응필터의 필터 계수 보상에 필요한 계산량을 감소시킬 수 있다. 실제 음성신호를 사용하여 제안된 실용적 구현 방법의 타당성을 검증하였다.

• Electronics and Telecommunications Trends
• /
• v.15 no.1 s.61
• /
• pp.38-40
• /
• 2000

자동 요금 징수 시스템인 ETC(Electronic Toll Collection) 시스템에서 차량의 탑재장치와 비컨(Beacon) 간에 마이크로파가 전파되는 경로를 모델화하였으며 다중 경로에 따른 페이딩 효과를 분석하였다. 또한 환경 변화 즉 강우 시 마이크로파 전파도 고려하여 수치분석을 하였다. 분석결과 강우에 의한 반사면의 반사계수가 변하여 페이딩 효과가 크게 증가하였다. 이런 수치해석 결과를 탑재장치에서 수신된 전압의 크기와 비컨과 차량 사이의 거리로 도시하였다.

• The Magazine of the IEIE
• /
• v.38 no.1
• /
• pp.50-55
• /
• 2011

초음파 시스템은 진단 영상뿐만 아니라 초음파 수술과 같이 초음파를 사용하여 특정 세포를 제거하거나, 또는 일반적인 수술을 위한 가이드 영상을 제공하는 등 그 활용이 증가되고 있다. 반면, 기존 초음파 시스템은 크기가 커서 클리닉 센터나 종합병원 등에서 이동성 및 공간 효율성이 낮고 환자에 관한 주치의들의 진단 활동 반경이 매우 제한적이라는 불편함을 초래한다. 본 논문은 서버 클라이언트 기반의 무선 초음파 진단 시스템에서 프루브가 수신한 초음파 반사 신호를 무선으로 실시간 전송하기 위해서 압축센싱과 산술 부호의 연접을 통한 손실 압축 알고리즘을 제안한다.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.37 no.11
• /
• pp.36-42
• /
• 2000

We calculate the facet reflectivity as a function of the waveguide width of buried channel waveguides using the angular spectrum method and the field profiles obtained by the effective index method, the variational method and the modified variational method, respectively and discuss the results. As the waveguide width increases, the facet reflectivity of buried channel waveguides approaches to that of slab waveguides. As the waveguide width decreases, the facet reflectivity of quasi-TE mode decreases from that of slab waveguides, while that of quasi-TE mode increases from that of slab waveguides. The variation of the facet reflectivity of quasi-TE mode as a function of waveguide width is much larger than that of quasi-TM mode. When the aspect ratio is one, the difference between the facet reflectivity of quasi-TE mode and that of quasi-TM mode using the variational method and the modified variational method is negligible, while the difference between the facet reflectivity of quasi-TE mode and that of quasi-TM mode using the effective index method is large. In the case of quasi-TE mode, the facet reflectivity using the angular spectrum method and the field profiles obtained by the modified variational method could be more accurate than that obtained by the effective method. In the case of quasi-TM mode, the facet reflectivities obtained by the various methods are almost the same.

• The Journal of the Korea institute of electronic communication sciences
• /
• v.15 no.5
• /
• pp.813-818
• /
• 2020

This study is a study on the characteristics and analysis of the reflected signals about the target in the VHF band. In advance, the RCS(Radar Cross Section) characteristics of the target were analyzed by using the CST electromagnetic analysis tool, and the target was detected by using the Bi-Static method, and the change in the signal-to-noise ratio was tested. The test results show similar results with no significant fluctuations in the signal-to-noise ratio characteristics for the detection of signals reflected on the target, such as the results for RCS analysis according to the pre-incidence angle. In the future, this study will be used for RCS analysis of the targets and target detection of Radar in VHF/UHF band with relatively large wavelength compared to the X band.

• Journal of the Institute of Electronics Engineers of Korea SD
• /
• v.42 no.5 s.335
• /
• pp.9-14
• /
• 2005

Simulation method for a pure radio-frequency (rf) mode of reflection-type and a pure rf mode of transmission-type radio-frequency single-electron transistor (RF-SET) operation is introduced. In this method, the solutions of differential equations based on Kirchhoff's law are obtained self-consistently at frequency-domain. Also, the steady-sate single-electron transistor (SET) current model and the time-dependent SET current model are used in this method. The reflected wave of a typical reflection-type RF-SET and the transmitted wave of a typical transmission-type RF-SET are calculated, and the accuracy of our developed method including the steady-state SET current model is verified with the method introduced by reference 2. At high frequency over GHz, results of our developed method including the time-dependent SET current model are considerably different from that including the steady-state SET current model. At high frequency over GHz, an exact time-dependent SET current model is needed to analyze RF-SET operation.