• 대한안전경영과학회지
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• 제4권4호
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• pp.137-146
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• 2002

In order to investigate the effect of irradiation by $^{60}Co-\gamma$rays as well as the e thermal treatment on the dielectric deterioration in ethylene propylene rubber, insulating material for electric cables used in atomic power plants, charging discharging current, residual built- up voltage and dielectric properties are measu discussed in this study. Variance in the characteristic of relative dielectric constant as a function of tem was observed in relatively high dose of irradiation. Since glass transition tem appeared at tens of degree Celsius below zero, the characteristic is attributed orientation polarization. Dielectric loss is generally increased, with increasing d irradiation in the characteristic of dielectric loss as a function of temperature, No d loss by thermal treatment was observed. Dielectric resistance decreases with increa of irradiation in the characteristic of charging current as a function of temperature be considered that dielectric resistance seems to be recovered by thermal treatm characteristic of discharging current as a function of time in the specimen less ir become similar to that of the unirradiated, when thermal treated. A peak is shown residual built- up voltage as a function of time, and the corresponding time of the shorten as increasing dose of irradiation. It is also observed that the corresponding the peak is lengthened by thermal treatment.

• 한국농림기상학회:학술대회논문집
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• 한국농림기상학회 2011년도 학술발표회
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• pp.16-18
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• 2011

Evaluation of climate change on the rice productivity was conducted using crop growth simulation model, where Odae, Hwaseong, Ilpum were used as a representative cultivar of early, medium, and medium-late rice maturity type, respectively, and climate change scenario 'A1B' was applied to weather data for future climate change at 57sites. When cropping season was fixed, rice yield decreased by 4~35% as climate change which was caused by poor filled grain ratio with high temperature and low irradiation during grain-filling. When cropping season was changed, rice yield decreased by only 0~5% as climate change which was caused poor filled grain ratio with low irradiation during grain-filling period. However, this irradiation decline was less than when cropping season was fixed. Therefore, we need to develop rice cultivars resistant to low irradiation which can maintain high filled grain ratio under poor irradiation condition, and late maturity rice cultivars whose growing period is longer than the present medium-late maturity type.

• 한국식품저장유통학회지
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• 제31권3호
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• pp.499-505
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• 2024

Patulin has been reported as a risk factor in various foods, especially apple juice. This study monitored residual patulin and polyphenolic content in apple juice during post-irradiation storage conditions. Response surface methodology (RSM) was applied to monitor the changes in dependent variables (Yn, patulin, and polyphenolics) as affected by independent variables, such as storage temperature (Xi, -20℃ to 20℃), irradiation dose (Xii, 0-2 kGy), and storage period (Xiii, 0-20 days), which were based on a central composite design. The predicted peak point resulted in the lowest residual patulin content of 58.42 ppb with the corresponding independent parameter conditions, such as 18.19℃ of storage temperature, 1.24 kGy of irradiation dose, and 13.42 days of storage period. The residual patulin content of 58.42 ppb is the minimum desirable level, representing a 91% reduction compared to the non-irradiated control (675.00 ppb). A maximum polyphenolics content (11.98 mg/g) was obtained under the predicted maximum conditions of 14.40℃, 0.78 kGy, and 3.4 days. The most influential parameter in reducing residual patulin content while maintaining polyphenolic content in apple juice was irradiation dose (p<0.01), which showed potential to be applied in controlling the patulin levels in apple juice.

• Nuclear Engineering and Technology
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• 제48권3호
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• pp.758-764
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• 2016

Specimens of stainless steel reactor internals were irradiated with 240 keV protons and 6 MeV Xe ions at room temperature. Nanoindentation constant stiffness measurement tests were carried out to study the hardness variations. An irradiation hardening effect was observed in proton- and Xe-irradiated specimens and more irradiation damage causes a larger hardness increment. The Nix-Gao model was used to extract the bulk-equivalent hardness of irradiation-damaged region and critical indentation depth. A different hardening level under H and Xe irradiation was obtained and the discrepancies of displacement damage rate and ion species may be the probable reasons. It was observed that the hardness of Xe-irradiated specimens saturate at about 2 displacement/atom (dpa), whereas in the case of proton irradiation, the saturation hardness may be more than 7 dpa. This discrepancy may be due to the different damage distributions.

• 한국초전도ㆍ저온공학회논문지
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• 제21권3호
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• pp.18-21
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• 2019

We studied the effect of Fe ion irradiation on the upper critical field ($H_{c2}$) of 410 nm single-crystalline $MgB_2$ thin films. The irradiation energy was fixed at 140 keV when we increased the irradiation doses from $1{\times}10^{14}ion/cm^2$ to $4{\times}10^{14}ion/cm^2$. We found that $H_{c2}$ significantly increase with increasing irradiation dose, despite the low irradiation energy. The enhancement of $H_{c2}$ could be explained by the reduction of electron mean free path caused by defects induced from irradiation, leading to a decrease of coherence length (${\xi}$). We also discussed the effect of irradiation on temperature-dependent resistivity in details.

• 한국군사과학기술학회지
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• 제15권2호
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• pp.208-214
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• 2012

The spectral radiance received by a remote sensor is consisted of the self-emitted component directly from the target surface, the reflected component of the solar irradiance at the target surface, and the scattered component by the atmosphere without ever reaching the object surface. In general, the self-emitted component is the most important part in the infrared signatures from the target. We measured the solar irradiation, sky irradiation, air temperature, wind velocity, wind direction, relative humidity, and atmospheric pressure together with the surface temperatures of rectangular parallelepiped targets. The measured diurnal surface temperature variations on the three different rectangular parallelepiped targets constructed by the steel, aluminum and bakelite are obtained at the same time intervals. The measured surface temperature results show that the top surface temperature of bakelite recorded up tp $7.6^{\circ}C$ higher than that of aluminium and $6.1^{\circ}C$ higher than that of steel at 11 AM on the sunny condition. A complete set of measured data including the surface temperature of rectangular parallelepiped targets together with the detailed weather information can be a valuable reference for future study.

• 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.

• Journal of Dairy Science and Biotechnology
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• 제23권2호
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• pp.93-98
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• 2005

본 연구는 항원성을 저감한 우유 및 유제품 개발을 위한 기초자료 도출을 위해 열처리와 감마선 조사 처리 시 우유의 화학적, 미생물학적 및 면역적 변화를 비교하였다. 열처리와 감마선 조사 처리 시 열처리 온도와 조사량이 높을수록 유리지방산 함량이 증가하는 경향을 나타내었으며 UHT 처리시와 5 kGy 조사시 유리지방산 함량은 유사하였다. $10^3$ CFU/mL 수준의 원유를 저온, 고온, 초고온으로 열처리시와 1${sim}$10 kGy로 감마선 조사처리 시 모두 일반세균과 대장균 군이 검출되지 않았으나, 일주일 지난 후에도 UHT 처리유와 5kGy 이상 조사 처리유에서 일반세균과 대장균 군이 검출되지 않았다. 원유를 열처리시 arginine, asparate, iso-leucine, leucine, lysine, methionine이 감소된 반면 조사처리에 의해 aspartate, histidine, iso-leucine, leucine, lysine이 감소되어 열처리와 조사처리가 단백질의 일차구조에도 영향을 미칠 수 있는 것(p<0.05)으로 나타났다. 또한, 우유의 항원성은 감마선 조사처리시 5kGy 이상에서 유의적(p<0.05)으로 감소하였다. 이상의 결과로 볼 때 5 kGy 정도의 감마선 조사처리로 UHT 처리시와 유사한 화학적, 미생물학적 효과와 우유의 항원성 감소효과를 기대할 수 있다.

• 한국환경과학회지
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• 제15권6호
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• pp.579-586
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• 2006

The purposes of this paper were to monitor the temperature rising courses and spark discharge of the modified granular activated carbon (GAC) by microwave (MW) irradiation and to evaluate absorption of benzene. The GAC coated on $SiO_2$, boron, talc, ferrite was named as the modified GAC. Thermal and spark discharge measurement of virgin GAC and modifed GAC has been carried out using a MW device operating at 2450 MHz under various energy conditions. The results of this paper as follows. First, the modified GAC is more efficient than the virgin GAC in temperature control. Temperature gradient of the modified GAC is more lower than that of virgin GAC. The temperature gradient of GAC was observed in the following order : virgin GAC, Mn-Zn ferrite/GAC, Ni-Zn ferrite,/GAC, $SiO_2/GAC$, Boron/GAC, Talc/GAC. Second, the spark discharge of the modified GAC was diminished, compared with that of virgin GAC. Because of its excellent electrical insulating properties, the coating material prevents the spark discharge. Finally, the benzene adsorption capacity of the modified GAC decreased due to diminishing of adsorption site by the coating material. Considering the temperature gradient and spark discharge of GAC, the GAC coated $SiO_2$ would be appropriate absorbent under irradiation of MW.

• 한국입자에어로졸학회지
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• 제11권3호
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• pp.77-85
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• 2015

A Belousov-Zhabotinsky reaction in a liquid-liquid system under microwave radiation was observed under non-stirring conditions. To control this non-equilibrium reaction, nano-particle, which is active under microwave irradiation, was added to the solution. Color changes of the solution during the oscillatory reaction were found to be influenced by the irradiation power although the droplet temperature was equal to the temperature of surrounding oil. During the irradiation, the period of oscillation became shorter because the reaction rate was faster. It could also be observed that there is possibility to eliminate oscillatory behaviors of the reaction using higher power of microwave. The possibility of controlling non-linear reaction using microwave was shown since microwave can easily travel through oil phase and reach water phase.