• Journal of Korean Dental Science
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• 제14권2호
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• pp.69-78
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• 2021

Purpose: The primary objective of this study was to evaluate the change in the temperature of the adhesive resin in polycrystalline ceramic brackets irradiated using a diode laser at different irradiation energy levels and times. Materials and Methods: For the measurement of the temperature of the adhesive resin, it was applied at the base of the ceramic bracket, a thermocouple was placed at the center of the base surface, the bracket was placed on prepared resin specimens for light curing, and a laser was irradiated to the center of the bracket slot at 5, 7, and 10 W. For the measurement of the temperatures of the enamel under the bracket and pulp cavity, extracted premolar was fixed to a prepared mold and the ceramic bracket was bonded to the buccal surface of the premolar. The Kruskal-Wallis H test and Friedman test were used for statistical analysis. Result: At 5 W, the temperature of the adhesive resin did not reach the resin softening temperature of 200℃ within 30 seconds. At 7 W, it reached 200℃ when the ceramic bracket was irradiated continuously for 28 seconds. At 10 W, it reached 200℃ when the ceramic bracket was irradiated continuously for 15 seconds. During laser irradiation, the temperature of the enamel under the bracket increased by over 5℃ within 15 seconds. Conclusion: The use of diode laser irradiation for bracket debonding should be carefully considered because the pulp cavity temperature increases by over 5℃ within the irradiation time for resin thermal softening.

• 한국재료학회지
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• 제33권11호
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• pp.497-501
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• 2023

ZnO/Cu/ZnO (ZCZ) thin films were deposited at room temperature on a glass substrate using direct current (DC) and radio frequency (RF, 13.56 MHz) magnetron sputtering and then the effect of post-deposition electron irradiation on the structural, optical, electrical and transparent heater properties of the films were considered. ZCZ films that were electron beam irradiated at 500 eV showed an increase in the grain sizes of their ZnO(102) and (201) planes to 15.17 nm and 11.51 nm, respectively, from grain sizes of 13.50 nm and 10.60 nm observed in the as deposited films. In addition, the film's optical and electrical properties also depended on the electron irradiation energies. The highest opto-electrical performance was observed in films electron irradiated at 500 eV. In a heat radiation test, when a bias voltage of 18 V was applied to the film that had been electron irradiated at 500 eV, its steady state temperature was about 90.5 ℃. In a repetition test, it reached the steady state temperature within 60 s at all bias voltages.

• 비파괴검사학회지
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• 제21권3호
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• pp.307-312
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• 2001

운전중인 원자로 재료의 건전성 평가를 위한 기계적 시험의 하나인 샤르피 충격 시험편에 대하여 초음파 신호분석이 이루어졌나 시험편으로는 모재와 용접재를 사용하였는데 이들 재료는 고온, 고압의 냉각수 및 지속적인 고속중성자가 방출되고 있는 가동중인 발전소에서 감시시험을 통한 원자로재료의 건전성평가를 목적으로 정지기간동안 인출된 깃이다. 분석결과 속도 및 감쇠와 같은 초음파 특성들이 재질이 비교적 균일한 모재에 있어서는 중성자 조사량과 밀접한 관련이 있는 것으로 보였으며 이를 활용하여 비파괴적인 방법으로 재료에 대한 중성자 조사량이 어느 정도인지를 예측할 수 있는 가능성을 보여주었다.

• 한국세라믹학회지
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• 제45권6호
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• pp.345-349
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• 2008

$TiO_2$ coating ceramic tile for self-cleaning purpose was prepared by the precipitant dropping method using $TiCl_4$ as a precursor. $TiO_2$ film was formed on the ceramic tile by spray-coating technique and heat-treated at $500^{\circ}C$ for 1 h. The size and crystalline structure of $TiO_2$ particles were 15.3 nm and anatase phase. The outdoor exposure tests were conducted and the effects of outdoor exposure test conditions, such as exhaust concentration of contamination materials (test places), the UV light intensity (irradiation direction) and coating amounts of $TiO_2$ on the self-cleaning properties were investigated by the brightness measurements. As a results, self-cleaning property of $TiO_2$ coating tile was affected by the coating amount of $TiO_2$ however, not affected by the UV light intensity included in sun's ray (irradiation direction). $TiO_2$ coating ceramic tile can be utilized for exterior finishing materials because of self-cleaning property of $TiO_2$ coating tile.

• 도서관문화
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• 제17권2호
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• pp.3-8
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• 1976

We sampled the fungi on the grounds of the floor and books in the library for the purpose of attack the fungi in the traditional library. We cultured it on the Sabouraud Dextrose Agar(Baltimore Biological Laboratory) and was obtained the fungi of six species, Here irradiated the ultra violet lamp(100V, 15W, 253Å), which was occurred to the colony after 24 hours. And irradiation by 2hrs/day for 2days here. The other method, we were sterilized test by the methanal fumigation The following results were obtained 1. All rearing is suspensed the result of the ultra violet rays irradiation, but the colony that is gained from the grounds of the floor in the library is not sterilized. 2. The result of air tight box to methanal 14ℊ/㎥ for the 24hours fumigation, each test group(the fungi of six species) is all sterilized.

• Journal of Welding and Joining
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• 제19권1호
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• pp.88-94
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• 2001

DUPIC (Direct use of spent PWR fuel in CANDU reactors) nuclear fuel is a CANDU fuel fabricated remotely from spent PWR fuel materials in a hot cell. The soundness of the end closure welds of nuclear fuel elements is an important factor for the safety and performance of nuclear fuel. To evaluate the soundness of the end closure welds of DUPIC fuel element, a precise X-ray inspection system is developed using a micro-focus X-ray generator with an image intensifier and a real time camera system. The fuel elements made of Zircaloy-4 and stainless steel by an Nd:YAG laser welding and a TIG welding aye inspected by the developed inspection system. The soundness of the welds of the fuel elements was confirmed by the X-ray inspection process, and the irradiation test of DUPIC fuel elements has been successfully completed at the HANARO research reactor.

• 한국식품조리과학회지
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• 제24권1호
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• pp.114-120
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• 2008

In this study, the effects of gamma irradiation on the microbial, physical characteristics, sensory qualities and antioxidant activity of Kongnamul Muchim(cooked soybean sprouts) were investigated. Gamma irradiation at 3 kGy inhibited microbial growth until 4 weeks of storange at $4^{\circ}C$ and until 5 days at and $25^{\circ}C$. The 3 kGy dose did not significantly affect the hardness of the sprouts; however Hunter's color values for lightness, redness and yellowness were changed. Low-dose gamma irradiation(up to 2 kGy) did not significantly affect the antioxidant activity of the Kongnamul Muchim. Also, based on a triangle sensory test, the gamma irradiated Kongnamul Muchim was not significantly different from the control. From these results, it is suggested that the applying gamma irradiation to cooked vegetables at doses lower than 3 kGy is recommended to extend shelf-life and maintain quality characteristics.

• Journal of Radiation Protection and Research
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• 제32권4호
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• pp.134-139
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• 2007

In order to find out the Radioprotective effect of algin-oligosaccharide(AOS), this study, with a mouse of which whole frame irradiated by 3 Gy radiation once, measured caspase-3 and caspase-9 amid cell signaling connected to apoptosis in order to observe cell activation. In Caspase-3 and Caspase-9 test for observing cell activation, both of Caspase-3 and Caspase-9 showed highly increased O.D. value in the irradiation control group, while the whole groups treated with algin-oligosaccharide before or after irradiation indicated lower O.D. value than the irradiation control group, especially showed big difference in 7 day's treatment group of before irradiation (P<0.001). It confirmed that Caspase generation was restrained in AOS treatment group. Consequently, this study inquired into the fact that algin-oligosaccharide with superior antioxidant activity performed radiation protection by inducing restraint of Caspase generation and confirmed that natural product with less chemical toxicity was able to be applied as radioprotector.

• 한국압력기기공학회 논문집
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• 제10권1호
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• pp.113-121
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• 2014

In this work, an integrated model including molecular dynamics and chemical rate theory was implemented to calculate the growth of point defect clusters(PDC) and copper-rich precipitates(CRP) which could change the mechanical properties of reactor pressure vessel(RPV) steels in a nuclear power plant. A number of time-dependent differential equations were established and numerically integrated to estimate the evolution of irradiation defects. The calculation showed that the concentration of the vacancies was higher than that of the self-interstitial atoms. The higher concentration of vacancies induced a formation of the CRPs in the later stage. The size of the CRPs was used to estimate the mechanical property changes in RPV steels, as is the same case with the PDCs. The calculation results were compared with the measured values of yield strength change and Charpy V-notch transition temperature shift, which were obtained from the surveillance test data of Korean light water reactors(LWRs). The estimated values were in fair agreement with the experimental results in spite of the uncertainty of the modeling parameters.

• 한국콘텐츠학회논문지
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• 제9권7호
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• pp.211-217
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• 2009

본 연구에서는 알긴산올리고당의 일부 방사선 방어효과를 규명하기 위해 마우스에 3 Gy 선량의 방사선을 1회 전신 조사하여 방사선 유도 nitric oxide를 측정하였다. 측정결과 방사선조사 대조군에서 nitric oxide 생성이 하강된 반면 방사선조사 전 3일간 처치군 및 방사선조사 후 3일간 처치군에서 유의한 생성 증가를 보였고, 특히 방사선조사 전 3일간 처치군에서 가장 큰 차이를 보였다(P<0.001). 결론적으로, 항산화효과가 탁월한 알긴산올라고당은 nitric oxide의 생성 증가를 촉진시킴으로써 일부 방사선 방어작용을 수행한다는 사실을 규명하였고, 화학적 독성이 적은 자연산생물이 방사선방어제로 활용될 수 있음을 확인하였다.