• Journal of Korean Society for Atmospheric Environment
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• v.24 no.E1
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• pp.24-31
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• 2008

In this study, a new PM (particulate matter) sampler was developed and fabricated to collect fine particles in the atmosphere, and laboratory and field tests were carried out to evaluate the performance of the sampler. The PM sampler, which was based on impingers, employed an aerosol condensation system as a PM magnifier to improve its collection efficiencies. Sodium chloride, ammonium sulfate and ammonium nitrate aerosols were used as test particles, because these components are rich in ambient aerosols. As a result, it was found that the collection efficiency of the novel PM sampler was very high. Thus, it is believed that the PM sampler is an effective device for sampling fine particles. In addition, it was demonstrated that this work could contribute to the collection or removal of fine particles and be applied to the semicontinuous sampling of ambient aerosols for chemical composition analysis.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.4
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• pp.479-485
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• 2014

Purpose: This study relates to the development of the prism dot-sight combined with the thermal imaging camera. Methods: We have placed a reflector designed to the doublet type in the front of a BS (beam splitting) prism, have placed an OLED panel and a dot reticle generator to the top and bottom of the reflecting surface of the BS prism, and have placed a detachable magnifier between the BS prism and the observer by which the observer can see the magnified image of the OLED panel. By doing this, we were able to configure the new type prism dot-sight combined with the thermal imaging camera. Results: By placing the removable magnifier designed with a new type between the BS prism and the observer, we could design the new type prism dot-sight which performs the role of the dot sight by removing the magnifier during the day-time, and performs the role of the night scope during the night-time by which we can observe the enlarged image of the thermal imaging camera through the BS prism by attaching the removable magnifier. Conclusions: In this study, we have developed the prism dot-sight combined with the thermal imaging camera which is able to play the role of the day or night scope selectively, by disposing the designed magnifier characterized by the focal length of 44 mm, the viewing angle of ${\pm}7.0^{\circ}$, and the MTF value of 0.5 or more at the criterion of 50 lp/mm and the 0.7 field between the BS prism and the observer. By doing so, we could design and fabricate the new type prism dot-sight combined with the thermal imaging camera which can further increase the rapidity of firing and provide more convenience in the mounting of a firearm than the detachable combination of an existing dot sight and an existing night scope.

• Journal of Technologic Dentistry
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• v.20 no.1
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• pp.5-11
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• 1998

The purpose of this study is to evaluate the castability and surface roughness of the casts using Non-percious alloys. For samples of 25 wax patterns, it is made from eight layers of sheet wax, arranged in the escalating layers. After fabricated wax patterns, using 5 kinds of Ni-Cr alloys is casted, and the casts are sandblasted. To castability, magnifier is used and values of surface roughness of the casts is measured with profilometer(tracing length 1.75mm, cutoff value 0.25mm) The results are as follows : 1. The castanbility of alloys, in case of C alloys, showed with $8.0{\pm}0.0000$, and in case of CS alloys and N alloys showed equal with $7.8{\pm}0.4472$, respectively. T alloys and V alloys showed equal with $7.2{\pm}0.4472$, respectively. 2. The values of surface roughness of the casts are decreased more T alloys than in case of order alloys, and in order, increased in case of CS alloys, C alloys, V alloys, N alloys, respectively.