• Korean Journal of Optics and Photonics
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• v.6 no.2
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• pp.93-100
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• 1995

3구면경계에서 aplanat 조건을 해석적으로 유도하고 이를 바탕으로 3종의 3차수차가 보정된 3구면 경계의 형태 및 존재영역을 조사하였다. 실상을 맺으면서 aplanat 저건을 만족하는 3구면경계는 유효초점거리가 양수인 경우 PPN, NPP, PNP 형태의 해가 존재하였으며 N은 볼록 거울, P는 오목 거울을 나타낸다. 유효초점거리가 음수인 경우 NPN, NPP, PNP, NNP형의 4종류의 형태가 존재하였다. 3종의 3차수차가 보정된 3구면경계에서 astigmatic aplanat는 실상을 맺는 해가 존재하지 않았다. Flat field aplanat는 PPN, PNP, NPP형태의 해가 존재하였고 distortion free aplanat의 경우는 PPN, PNP, NPN, NPP, NNP형의 해가 존재하였다.

• Proceedings of the Optical Society of Korea Conference
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• 1991.06a
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• pp.81-87
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• 1991

A design of a four-mirror optical system for submicron lithography using KrF excimer laser beam(λ=248nm) is presented. By using the third order aberration theory, analytic solutions for a telecentric, flat-field, and anastigmatic four-spherical-mirror system (reduction magnification 5$\times$) are found. Aspherization is carried out to the spherical mirror surfaces in order to reduce the residual higher order aberrations and vignetting effect. Finally we obtain a reflection system useful in submicron lithographic application.

• Journal of the Korean Institute of Telematics and Electronics
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• v.26 no.9
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• pp.1348-1358
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• 1989

We analyzed electrostatic lens with axi-symmetic configurations using the analytic equation for a single apertured lens. The developed computer code afforded to estimate ion optical properties such as ion trajectories, aberrations and ion beam diameters, and was found to have advantages of a shorter calculation time. The calculated ion optical properties for several types of electrostatic lens were in good agreement with Burghard's ones and it was seem that 20% reduction of ion beam diameter could be obtained by the change of aperture diameters.

• 대한방사선방어학회:학술대회논문집
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• 2009.04a
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• pp.164-165
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• 2009

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• Proceedings of the Optical Society of Korea Conference
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• 2003.02a
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• pp.134-135
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• 2003

인체안의 단색수차는 시력의 한계를 규정하고 또한 안광학 기기의 설계에 있어서 중요한 요소이기 때문에 오래 전부터 많은 관심을 갖게 되었다. 또한 단색수차를 정밀하게 측정함으로써 가장 이상적인 시력 교정 방법을 찾을 수 있다. 본 연구에서는 먼저 그림 1과 같은 Shack-Hartmann (SH) 파면분석기를 구성하였다. 이 파면분석기는 대물렌즈, 결상렌즈, 미소렌즈배열(microlens array, MLA), 그리고 이미지 센서(CCD)로 구성되어 있다. (중략)

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2002.05a
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• pp.66-66
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• 2002

• Vacuum Magazine
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• v.2 no.2
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• pp.24-28
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• 2015

The brightness of an electron source, along with the aberrations of an objective lens, determines the image resolution and beam current on samples, which are two important parameters for evaluating the performance of an electron microscope. Here we introduce thermal electron source, Schottky emitter and cold field electron emitter. Thermal electron source is the cheapest and stable electron source but it has the lowest brightness. Schottky emitter is 10000 times brighter than tungsten thermal electron source, but requires ultrahigh vacuum operating condition. Cold field electron emitter is 10 times brighter than Schottky emitters, but it is rather unstable and its operation requires most stringent vacuum condition, hindering its widespread use.

• Proceedings of the Korean Society of Toxicology Conference
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• 2003.10b
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• pp.147-147
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• 2003

Human exposure to benzene is derived occupationally from the petrochemical and petroleum refining industries. This study was carried out to find whether the frequencies of chromosome aberrations in workers exposed to low level benzene in a petroleum factory were elevated compared to non-exposed workers.(omitted)

• Journal of Space Technology and Applications
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• v.1 no.1
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• pp.104-120
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• 2021

Some optical schemes of lenses for spacecraft developed by the author are considered. The main optical characteristics of telescope lenses of various architectures are compared. We propose compact solutions of mirror, lens-mirror, and lens systems with maximum available angular resolutions and other parameters. Examples of calculating the optical systems of lenses used for various tasks both in the field of astronomy and in the field of remote sensing of the Earth and other planets are given. The example of onboard computer system is discussed. Practical recommendations on the development and use of telescope lenses are given.

• The Bulletin of The Korean Astronomical Society
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• v.46 no.2
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• pp.55.5-56
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• 2021

The optical design of the Linear-Astigmatism-Free Three-Mirror-System (LAF-TMS) for KASI-Deep Rolling Imaging Fast-optics Telescope(K-DRIFT) is presented. LAF-TMS is an all-reflective imaging system consists of three freeform mirrors. Due to its well-corrected aberrations and obstruction-free clear aperture, the LAF-TMS provides a wide field of view with very low scattered lights.