• The Bulletin of The Korean Astronomical Society
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• 제38권2호
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• pp.68.2-68.2
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• 2013

Camera for QUasars in EArly uNiverse (CQUEAN) is an optical CCD camera system made by Center for Exploration of the Origin of the Universe (CEOU). CQUEAN is developed for follow-up observation of red sources such as high-redshift quasar candidates ($z{\geq}5$), gamma-ray bursts (GRB), brown dwarfs and young stellar objects. The CQUEAN is composed of a science camera with deep-depletion CCD chip which is sensitive at around $1{\mu}m$, a set of custom-made wide-band filters for detection of quasar candidates at z~5, and a guide camera. A focal reducer was developed to secure $4.8^{\prime}{\times}4.8^{\prime}$ field of view, and an in-house user software for efficient data acquisition. CQUEAN was attached to 2.1m Otto Struve Telescope in McDonald Observatory, USA, in August 2010. About 1000 quasar candidates including 3 confirmed with follow-up spectroscopy, have been observed so far, and many high-z galaxy cluster candidates, GRBs and supernovae were also observed. And monitoring of HBC 722, a young stellar object, is under way since 2011. Further enhancement of CQUEAN including the introduction of narrow-band filters is planned.

• Journal of Dental Rehabilitation and Applied Science
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• 제20권2호
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• pp.109-120
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• 2004

INTRODUCTION: The build-up method has been used for application of porcelain powder on the metal framework to make final tooth shape conventionally. This method takes time and need skill to mimic final shade and shape of porcelain fused to metal crown. The purpose of this study was to develop standard shape and shade laminating porcelain forms to reduce build-up time. METHODS: To make tooth form porcelain paste, several liquid organic compounds were added to conventional feldspathic porcelain. The amount of additives and rheologic property were tested to find out best composition. Comparison of mixing methods to reduced porosity, proper heating schedule, and measurement of shrinkage amount and residual organic materials were performed to set-up standard procedures. Finally, biaxial flexural strength and color of preformed laminated paste porcelain were compared with those of porcelain which fabricated by the conventional build-up method. RESULTS: There was no significant difference in physical properties and color stability between two fabrication methods after various testing methods. Conclusion: This new build-up method can be applied to fabricate the PFM crown and bridge without any loss of strength and optical properties.

• Journal of the Korea institute for structural maintenance and inspection
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• 제13권1호통권53호
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• pp.88-96
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• 2009

This study proposes a wireless measurement system that is a new safety management system by using an FBG sensor and a PDA. The sensor part has many advantages of implementing a wireless measurement system, and the study emploies an FBG-LVDT sensor, FBG-STRAIN sensor, FBG-TEMP sensor, and FBG-ACC sensor, using FBG sensors. Also, the study show a configuration of a signal process system for operating a wireless transmission system of FBG sensors applied to the signal process system, and engrafted the cutting edge information technology industry in order to display from a remote distance using a PDA. In order to verify the applicability of the developed FBG sensors and wireless measurement monitoring system to the field, their accuracy, and usability, the study has conducted a static and dynamic test to a bridge in the field. The study made an assessment of service for the vibration of the bridge by applying dynamic data measured by an FBG-LVDT sensor and FBG-ACC sensor to Meister's curve and prepared methods for assessing the vibration of the bridge by proposing a standard of vibration limitation given the service of vibration of the bridge. As a follow up for this study, it would be necessary to set up an overall model for the standard of service assessment established in this study.

• Journal of Korean Ophthalmic Optics Society
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• 제16권4호
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• pp.409-415
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• 2011

Purpose: To design applied anamorphic lens that focal length ratio is 3:1 optical system to improve detecting distance. Methods: We defined a boundary condition as $50^{\circ}{\sim}60^{\circ}$ for viewing angle, horizontal direction 36mm, vertical direction 12 mm for focal length, f-number 4, $15{\mu}m{\times}15{\mu}m$ for pixel size and limit resolution 25% in 33l p/mm. Si, ZnS and ZnSe as a materials were used and 4.8 ${\mu}m$, 4.2 ${\mu}m$, 3.7 ${\mu}m$ as a wavelength were set. optical performance with detection distance, narcissus and athermalization in designed camera were analyzed. Results: F-number 4, y direction 12 mm and x direction 36 mm for focal length of the thermal optical system were satisfied. Total length of the system was 76 mm so that an overall volume of the system was reduced. Astigmatism and spherical aberration was within ${\pm}$0.10 which was less than 2 pixel size. Distortion was within 10% so there was no matter to use as a thermal optical camera. MTF performance for the system was over 25% from 33l p/mm to full field so it was satisfied with the boundary condition. Designed optical system was able to detect up to 2.9 km and reduce a diffused image by decreasing a narcissus value from all surfaces except the 4th surface. From sensitivity analysis, MTF resolution was increased on changing temperature with the 5th lens which was assumed as compensation. Conclusions: Designed optical system which used anamorphic lens was satisfied with boundary condition. an increasing resolution with temperature, longer detecting distance and decreasing of narcissus were verified.

• Journal of the Institute of Electronics Engineers of Korea TC
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• 제43권5호
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• pp.182-188
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• 2006

In this study, we have designed the millimeter-wave passive imaging system which records energy that is reflected or emitted from the source and produces image. The lens and front-end of receiver appeared to be important in the system to detect input thermal noise signal. The lens for signal focusing has been designed by optical transfer function. Amplifier of the imaging systemhas been set up with 40dB in maximum gain, 5 dB in maximum noise figure, and 10GHz in bandwidth to enhance sensitivity for thermal noise and to receive it in wide-band width as well. The SBD MSS-20 141B10D diode has been used for the detector circuit to convert amplified millimeter-wave signals to DC output.

• Journal of the Korea Convergence Society
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• 제8권12호
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• pp.391-395
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• 2017

In this research, we conducted a questionnaire survey of contents necessary for eyeglass dispensing & fitting fee and characterization solution of eyeglass dispensing & fitting fee. From August 1, 2016 to September 30, questionnaires were set up for 202 spectators of Seoul and Gyeonggi area, questionnaire survey was conducted online and offline. Statistical processing of all data was performed using Origin Pro 8.5. 92.1% (186 people) and 93.1% (188 people) were positively evaluating the necessity of introduction for the necessity of introducing eyeglass dispensing & fitting fee, respectively. The result suggested that it is necessary to establish the position of the optician as a medical service expert by providing a more stable policy through analysis of overseas cases of eyeglass dispensing & fitting fee.

• Journal of the Korean Wood Science and Technology
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• 제36권6호
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• pp.96-104
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• 2008

In this study, the observation of test pieces with an optical microscope was carried out after fabricating 4 groups of standard lacquer, in order to inquire into the ancient lacquering techniques. Group I had transparent reddish brown color, and the part of layer was indefinite, and the layer polished was easily distinguished. Group II had mostly transparent yellowish brown color, and it was possibility distinguished the layers when they were varnished with mixed lacquer after prime coating, and when they were varnished with lacquer as the prime coating. Group III set up membrane in the hardening process of the lacquer, and the lacquer and the unsaturated fatty acid of internal part was dried, so the top layer and the lacquer layer were separated and observed. Group IV: When the lacquer coat film of Group IV test pieces were observed in polarized light, the ferrous components were seen as the black and red color were mixed, and the silica crystals of silty soil were distinguished by reflection of lights. And the colors were distinguished as the lacquer layer of ruddle had red color, and the mixed lacquer of reddish lacquer and ruddle had the deep red color at the top and the bottom, but the middle part had the bright red color.

• Journal of the Korean Society for Nondestructive Testing
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• 제14권2호
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• pp.112-121
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• 1994

This paper discusses the feasibility of ultrasonic C-scan technique for nondestructive evaluation of spot weld quality. Ultrasonic evaluation for spot weld quality was performed by immersion method with the mechanical and the electronic scanning of point-focussed ultrasonic beam(25 MHz). For the sake of the approach to the quantitative measurement of nugget diameter and the discrimination of the corona bond from nugget, preliminary infinitesimal gap experiment by newton ring is tried in order to set up the optimum ultrasonic test condition. Ultrasonic image data obtained were confirmed and compared by optical microscope and SAM(Scanning Acoustic Microscope) observation of the spot-weld cross section. The results show that the nugget diameter can be measured with the accuracy of 1.0mm, and voids included in nugget can be detected to $10{\mu}m$ extent with simplicity and accuracy. Finally, it was found that it is necessary to make a profound study of definite discrimination of corona bond from nugget and the approach of quantitative evaluation of nugget diameter by utilizing the various image processing techniques.

• Journal of Plant Biotechnology
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• 제30권2호
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• pp.207-214
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• 2003

This study was carried out to establish a novel bioassay system for screening of compounds affecting aromatic amino acid or anthocyanin biosynthesis through investigating a degree of sucrose-induced anthocyanin formation such as size of plant material, buffer conditions, light intensity and irradiated duration, incubation temp., etc were determined and standard procedure (suitable experimental condition) was set up as follows. The second leaf blade of white corn seeding induced by fluridone treatment were segmented into a size of 5${\times}$5 min. The segments were floated on the solution of 1% sucrose in 1.0mM MES buffer (pH6.0∼6.5) and incubated at 26$^{\circ}C$ for 2days under the continuous light condition(70∼100$\mu$mol m$^{-2}$ s$^{-1}$ ). Anthocyanin in the purpled tissues was extracted with methanol containing 1% HCl and the optical density of the clear supematants was determined at 528mm. Influences of some chemicals were tested using this system. Glyphosate, 5-enolpyruvylshikimate 3-phosphate synthase inhibitor, showed most sensitive response with I$_{50}$ value at 3.3$\mu$M. Dicyclohexylcarbodiimide(DCCD) and parachloromercuribenzenesulfonic acid(PCMBS) had a relatively strong ingibition with I50 value at 7.1$\mu$M and 10.2$\mu$M, respectively. These results show that sucrose-induced anthocyanin formation in white com leaf segment provide a very simple and rapid system for searching new compounds affecting aromatic amino acid or anteocyanin biosynthesis by screening at less than 10$\mu$M.

• Korean Journal of Optics and Photonics
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• 제15권6호
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• pp.519-526
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• 2004

We developed a 2-D imaging system to detect ultra weak biophoton by using a high sensitive fast CCD camera. We installed an illumination apparatus to generate delayed luminescence from plant leaves. Shutters at the illumination system and detector were synchronized to each other. The lens system of the CCD camera was newly designed to accommodate the specific requirements to enhance the collection efficiency for biophoton. Based on the lens simulation, commercial lenses were chose for the lens system. All the equipment was installed in a multi-purpose dark box and the delayed luminescence of Euonymus japonica was successfully acquired.