• Proceedings of the Korean Society of Precision Engineering Conference
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• 2013.05a
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• pp.641-642
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• 2013

• Journal of the Optical Society of Korea
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• v.13 no.3
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• pp.330-334
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• 2009

A simple and compact frequency swept laser is demonstrated at $1.3{\mu}m$ using a wavelength scanning filter based on a rotating slit disk. The laser is comprised of a pigtailed semiconductor optical amplifier, a circulator, and a wavelength scanning filter in an extended cavity configuration. The wavelength scanning filter is composed of a collimator, a diffraction grating, a rotating slit disk, and a mirror. The instantaneous laser output power is more than 5 mW. The scanning range of the laser is extended to 80 nm at the maximum level, and 55 nm in the full width at half maximum at a scanning rate of 2 kHz.

• Journal of the Optical Society of Korea
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• v.20 no.1
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• pp.180-187
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• 2016

The independent operation of a color filter for incident polarization is demonstrated using a guided-mode resonance (GMR) filter employing a metal-insulator-metal (MIM) waveguide. To achieve independent operation, a rectangular MIM grating is proposed as a wave-guide resonator. The design considerations are discussed and include how to determine the grating period and slit width. Power flow distribution is observed with slit width variation. Blue-green, green-red, and blue-red filters for corresponding x- and y-polarizations are demonstrated as application examples with numerical simulation with rectangle-shaped MIM grating. As a practical application, feasibility as a chromatic polarizer is discussed.

• Publications of The Korean Astronomical Society
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• v.15 no.spc1
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• pp.39-60
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• 2000

We will discuss two-dimmensional spectrophotometry including long-slit spectroscopy and narrow-band imaging. The basic principles, applications, and techniques of observations and data reduction of spectroscopy and spectrophotometry for extended objects are described. This discussion will focus on practical long-slit spectroscopy using a Cassegrain spectrograph attached with 2 or 4m class telescopes and on imaging spectrophotometry using narrow-band interference filter sets. We will discuss scientific applications.

• Bulletin of the Korean Space Science Society
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• 2011.04a
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• pp.31.2-31.2
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• 2011

IGRINS (Immersion GRating INfrared Spectrometer) is a high resolution wide-band infrared spectrograph developed by Korea Astronomy and Space Science Institute (KASI) and the University of Texas at Austin (UT). The slit-viewing camera is one of four re-imaging optics in IGRINS including the input relay optics and the H- and K- band spectrograph cameras. Consisting of five lenses and one Ks-band filter, the slit viewing camera relays the infrared image of $2'{\times}2'$ field around the slit to the detector focal plane. Since IGRINS is a cryogenic instrument, the lens barrel is designed to be optimized at the operating temperature of 130 K. The barrel design also aims to achieve easy alignment and assembly. We use radial springs and axial springs to support lenses and lens spacers against the gravity and thermal contraction. Total weight of the lens barrel is estimated to be 1.2 kg. Results from structural analysis are presented.

• Journal of Institute of Control, Robotics and Systems
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• v.7 no.8
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• pp.656-663
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• 2001

This paper presents a sensor fusion method to recognize a cylindrical object a CCD camera, a laser slit beam and ultrasonic sensors on a pan/tilt device. For object recognition with a vision sensor, an active light source projects a stripe pattern of light on the object surface. The 2D image data are transformed into 3D data using the geometry between the camera and the laser slit beam. The ultrasonic sensor uses an ultrasonic transducer array mounted in horizontal direction on the pan/tilt device. The time of flight is estimated by finding the maximum correlation between the received ultrasonic pulse and a set of stored templates - also called a matched filter. The distance of flight is calculated by simply multiplying the time of flight by the speed of sound and the maximum amplitude of the filtered signal is used to determine the face angle to the object. To determine the position and the radius of cylindrical objects, we use a statistical sensor fusion. Experimental results show that the fused data increase the reliability for the object recognition.

• 전기의세계
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• v.34 no.9
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• pp.548-552
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• 1985

서울대학교 병원에서는 약2년간의 이분야에 대한 기초 및 임상연구 결과를 토대로 하여 D.S.R.System을 개발하고 있다. 현재 개발하고 있는 Systme은 다음과 같다. 1) X선 발생장치 및 Control부분 2) 산란효과 제거를 위한 fore-slit 및 after-slit과 구동장치 3) X선을 광신호로 변환하기 위한 rare earth screen과 광신호를 전기적인 신호로 변환시키기 위한 photo-diode array detector의 결합체, 4) data 수집부분, 증폭장치와 A/D변환기, 고속 data 저장용 기억장치 부분 5) data 처리와 display를 위한 Bit-slice processor 5) Picture Archiving and Communication Systems (PACS) 이러한 부분 이외에 SNR을 향상시키고 좁은 부위의 region of interest를 보다 정확하게 관찰하기 위해서 511p/mm의 고밀도 선형검출기를 병행으로 사용하고 있다. 이 선형검출기를 이용하여 일부의 영상을 관찰하여 그 결과를 Wiener filter 등의 방법의 매개변수 선정에 이용하여 전체적인 영상의 질을 향상시키고자 하는 것이다.

• Journal of The Korean Astronomical Society
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• v.36 no.spc1
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• pp.45-47
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• 2003

A white light flare was observed at the limb on 16 August 1989 in He 10830 ${\AA}$ spectra, H$\alpha$ slit jaw photo-grams, and white light filter-grams of ${\lambda}=5600{\AA}{\pm}800{\AA}$. The kernels of the white light flare are not spatially related with Ha brightenings, suggesting that the flare energy would be released at the photosphere.

• Journal of the Korean Society of Tobacco Science
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• v.16 no.2
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• pp.191-197
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• 1994

Relationships between surface structure and adsorption properties of smoke components were investigated in surface-modified and un-modified activated carbon filter cigarettes. Commercially available activated carbon was treated with nitric acid and hydrogen peroxide as oxidant, and their pore volume, surface structure, BET surface area, pore type and size were studied. BET surface area and pore volume were decreased by nitric acid treatment, but median pore diameter was 8.1 $\AA$, which showed better development of pore compared with that of un-modified activated carbon, 6.9 $\AA$. In case of hydrogen peroxide treatment, BET surface area and pore volume were increased. Their pore was found to be a slit type based on V-t plot analysis. Neutralization capacities for bases of different strength (NaHCO3, Na2CO3, NaOEt and NaOH) showed that the majority of the acidic surface groups are of weak acidity. Modification of the activated carbon surface led to a slight change in adsorption properties when analyzing the smoke of triple-filter cigarette with surface-modified activated carbon.

• Journal of the Korean Society for Precision Engineering
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• v.9 no.1
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• pp.82-95
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• 1992

There is the high interest for sensing of tool wear with the aim of controlling machine tools productivity from the point of view of qualitity. Difficulties in this measurement are also known. This study is on the development of measurement setup for crater wear by CCD image inturning. In this study, the crater wear measurement system consists of the He-Ne gas laser, diffraction grating. CCD camera, noise filter, slit, microcomputer, diverging lens, converging lens and so on. He-Ne laser beam passes through a diverging lens and a diffraction grating is positioned properly. A converging lens focuses so that the interference fringes can be obtained on the crater wear. Performance test revealed that the developed image technique provides precise, absolute tool-wear quantification and reduces human measurement errors. The results obtained are as follows 1. The digitizing of one image requires less than 2ses. 2. It can give detailed information on crater wear with limited times and errors 3. All parameters required by specification are easily obtained for several points of the cutting edge.