• 대한전기학회논문지
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• 제34권7호
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• pp.289-296
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• 1985

The Townsend primary ionization coefficient a was measured by the luminous-flux method using the fact that the intensity of radiant light is proportional to electron density in the townsend discharge domain. The ranges of measurements were 15for He gas and 10

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2006년도 춘계종합학술대회
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• pp.365-367
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• 2006

광용적맥파를 이용하여 일상생활에서 심장 박동을 관찰하고 심장 박동의 이상을 경고할 수 있는 저렴하면서도 간단한 심박 측정 장치를 구성하고 심장박동을 검출하였다. 심장박동의 검출을 위해 Ring형 광용적맥파 센서를 635nm의 적색 LD와 Si Photodiode로 제작하였다. 제작된 Ring형 광용적맥파 센서는 잡음 및 오차로 작용하는 외부 광원을 차단하였으며, 동(動)잡음의 영향을 최소화하기 위해 측정부위에 밀착하도록 하였다, 측정결과 제작된 센서는 심장박동 신호를 외부 영향 없이 안정적인 검출이 가능함을 알 수 있었다.

• Journal of the Optical Society of Korea
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• 제17권1호
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• pp.73-80
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• 2013

In the process of lithography using ultra violet light sources for semiconductor devices, most of defects are made by sub-micrometer pollutants generated at photochemical reactions. We proposed and developed a novel vibration-insensitive on-axis interferometer with a sub-micrometer lateral resolution by using the interference between two beams: one scattered from defects and the other reflected from a reference area without defects. The proposed system was successfully demonstrated to detect a small Al defect of 0.5 ${\mu}m$ diameter within the inspection time of less than 30 minutes over the area of the photo-mask which is 6 inch by 6 inch square.

• 한국입자에어로졸학회지
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• 제13권1호
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• pp.25-31
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• 2017

This paper offer the characteristics for the detection and classification of biological and non-biological aerosol particles in the air by using laser-induced-fluorescence (LIF) based Bio-aerosol Detection System (BDS). The BDS is mainly consist of an optical chamber, in-outlet nozzle system, 405 nm diode laser, an avalanche photo detector (APD) for scattering signal and photomultiplier tubes (PMT) for fluorescence signals in two different wavelength range ; F1, 510-600 nm and F2, 435-470 nm. The detection characteristics, especially ratio of fluorescence signal intensity were examined using well-known components : polystylene latex (PSL), fluorescence PSL, $2{\mu}m$ of SiO2 micro sphere, dried yeast, NADH, ovalbumin, fungicide powder and standard dust. The results indicated that the 405 nm diode laser-based LIF instrument can be a useful bio-aerosol detection system for unexpected biological threaten alter in real-time to apply for dual-use technology in military and civilian fields.

• 한국정보통신학회논문지
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• 제13권10호
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• pp.2189-2196
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• 2009

광파이버 네트웍에서 광전믹싱 광검파의 가용 주파수대역 확장을 위한 이론을 제시하고 시뮬레이션을 실시하였다. 광전믹싱 광검파의 정규화 이득을 정의하고, 검파소자의 차단주파수를 초월하는 고주파 영역의 신호도 검파가 가능함을 확인하였다. 포토다이오드 내부의 캐리어 천이에 대한 연속방정식을 풀어서 광전믹싱 현상의 메카니즘을 해석하였다. 정규화 이득은 신호주파수와 차주파수의 크기에 의존하였으나, 포토다이오드에 흐르는 광전류의 크기는 신호주파수와는 무관하였다. 신호 검파효율의 최대화를 위해서는 바이어스 전압과 국부신호의 진폭을 동시에 최적화할 필요가 있다.

• 전기학회논문지
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• 제58권7호
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• pp.1386-1392
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• 2009

An analysis is presented for super-high-speed optical demodulation by an avalanche photodiode(APD) with electric mixing. A normalized gain is defined to evaluate the performance of the optical mixing detection. Unlike previous work, we include the effect of the nonlinear variation of the APD capacitance with bias voltage as well as the effect of parasitic and amplifier input capacitance. As a results, the normalized gain is dependent on the signal frequency and the frequency difference between the signal and the local oscillator frequency. However, the current through the equivalent resistance of the APD is almost independent of signal frequency. The mixing output is mainly attributed to the nonlinearity of the multiplication factor. We show also that there is an optimal local oscillator voltage at which the normalized gain is maximized for a given avalanche photodiode.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2011년도 전력전자학술대회
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• pp.378-379
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• 2011

PV system's islanding occurs when the uitilty grid is removed but local sources continue to operate and provide power to local loads. Islanding is one of the serious problems in an electric power system connected with dispersed power sources. Also, this can present safety hazards and the possibility of damage to other electric equipments. If the real and reactive power of RLC load and PV system are closely matched, islanding detection by passive methods becomes difficult. Novel islanding detection method is proposed for grid-connected PV system.

• 한국전자통신학회논문지
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• 제7권2호
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• pp.303-308
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• 2012

실린더 형태의 롤러에 감기는 원단들의 가장자리에 있는 선 이나 면들을 감지할 수 있는 1차원 선면감지 센서에 대하여 연구하였다. 선면감지 센서는 광학계의 정렬을 필요로 하지 않는 1안 렌즈를 사용한 1:1 광학계를 사용하였고 2분할 실리콘 수광소자를 사용한 두 개 채널로 부터의 차 및 합 신호를 처리하여 구현하였다. 측정된 결과는 다양한 재질 및 색상을 갖는 피사체에 대해서도 0.1mm 까지 선폭을 감지할 수 있었으며 감기는 원단은 0.2mm 편차 이내로 감기는 것을 보여주었다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.540-540
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• 2012

Selective detection of single nucleotide polymorphism (SNP) of Cytochrome P450 2C19 (CYP2C19) was carried out by the PNA chips which were electrically-interfaced with interdigitated nanogap electrodes (INEs). The INEs whose average gap distance and effective gap length were about ~70 nm and ${\sim}140{\mu}m$, respectively, were prepared by the combination of the photo lithography and the surface-catalyzed chemical deposition, without using the e-beam lithography which is almost inevitable in the conventional lab-scale fabrication of the INEs. Four different types of target DNAs were successfully detected and discriminated by the INE-based PNA chips.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권6호
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• pp.789-796
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• 2014

A CMOS photo detection bias quenching circuit is developed to be used with single photon avalanche photodiodes (SPADs) operating in Geiger mode for the detection of weak optical signals. The proposed bias quenching circuits for the performance improvement reduce the circuit size as well as improve the performance of the quenching operation. They are fabricated in a $0.18-{\mu}m$ standard CMOS technology to verify the effectiveness of this technique with the chip area of only $300{\mu}m^2$, which is about 60 % of the previous reported circuit. Two types of proposed circuits with resistive and capacitive load demonstrated improved performance of reduced quenching time. With a commercial APD by HAMAMATSU, the dead time can be adjusted as small as 50 ns.