• Journal of the Korea Institute of Military Science and Technology
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• v.18 no.3
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• pp.293-299
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• 2015

We analyzed the damage effect on Glass Fibre Reinforced Plastics(GFRP) under air flow by irradiation of continuous wave near-IR laser. Damage process and temporal temperature distribution were demonstrated and material characteristics were observed with laser intensity, surface flow speed and angle. Surface temperature on GFRP rapidly increased with laser intensity, and the damaged pattern was different with flow characteristics. In case of no flow, penetration on GFRP by burning and flame generation after laser irradiation was appeared at once. GFRP was penetrated by the heat generated from resin ignition. In case of laser irradiation under flow, a flame generated after burning extinguished at once by flow and penetration pattern on GFRP were differently shown with flow angle. From the results, we presented the damage process and its mechanism.

• Journal of Radiation Industry
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• v.4 no.4
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• pp.381-384
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• 2010

In this study, the microbial safety and mechanical properties of xeno-bone graft material irradiated were investigated during the storage. Xeno-bone graft of the deminerlized bone matrix in carboxy-methyl-cellulose was gamma-irradiated and was cultured in PCA and PDA agar to check microbial contamination. Total aerobic bacteria and fungi were not detected in the irradiated and non-irradiated sample stored in accelerator at $30^{\circ}C$ for 10 months. Viscosity of CMC treated gamma irradiation was also not changed by holding period.

• Food Science and Preservation
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• v.14 no.3
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• pp.239-246
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• 2007

The effects of gamma irradiation on the physiochemical and physical characteristics of apples were investigated during post-irradiation storage at $4^{\circ}C\;and\;25^{\circ}C$. The contents of total and reducing sugars were analyzed and the results indicated that apples receiving 1 kGy of gamma irradiation did not show significant differences in sugar contents compared to non-irradiated controls. Important physiological characteristics were evaluated by measurement of total phenolic content and total flavonoid content, reducing power, and radical scavenging ability, and the results indicated that gamma irradiation at a dose of 1 kGy did not affect physiological activities. Changes in physical parameters such as weight loss, strength, cohesiveness and hardness, during post-irradiation storage, were temperature-dependent, whether the apples were irradiated or not The color and sensory acceptance of the apples were not affected by irradiation during cold storage. However, minor deterioration in color quality and sensory acceptance of irradiated apples was noted under ambient temperature storage. We conclude that gamma irradiation(1 kGy) does not affect apple nutritional content stability, functional properties, or physical characteristics, especially upon cold storage after radiation treatment.

• Nuclear Engineering and Technology
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• v.56 no.1
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• pp.147-159
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• 2024

Plutonium-238 has always been considered as the one of the promising radioisotopes for space nuclear power supply, which has long half-life, low radiation protection level, high power density, and stable fuel form at high temperatures. The industrial-scale production of ²³⁸Pu mainly depends on irradiating solid ²³⁷NpO₂ target in high flux reactors, however the production process faces problems such as large fission loss and high requirements for product quality control. In this paper, a conceptual design study of producing ²³⁸Pu in a multi-purpose high flux reactor was evaluated and analyzed, which includes a sensitivity analysis on ²³⁸Pu production and a further study on the irradiation scheme. It demonstrated that the target structure and its location in the reactor, as well as the operation scheme has an impact on ²³⁸Pu amount and product quality. Furthermore, the production efficiency could be improved by optimizing target material concentration, target locations in the core and reflector. This work provides technical support for irradiation production of ²³⁸Pu in high flux reactors.

• Nuclear Engineering and Technology
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• v.45 no.3
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• pp.311-322
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• 2013

High-Cr martensitic steel HT-9 is one of the candidate materials for advanced nuclear energy systems. Thanks to its excellent thermal conductivity and irradiation resistance, ferritic/martensitic steels such as HT-9 are considered for in-core applications of advanced nuclear reactors. The harsh neutron irradiation environments at the reactor core region pose a unique challenge for structural and cladding materials. Microstructural and microchemical changes resulting from displacement damage are anticipated for structural materials after prolonged neutron exposure. Consequently, various irradiation effects on the service performance of in-core materials need to be understood. In this work, the fundamentals of radiation damage and irradiation effects of the HT-9 martensitic steel are reviewed. The objective of this paper is to provide a background introduction of displacement damage, microstructural evolution, and subsequent effects on mechanical properties of the HT-9 martensitic steel under neutron irradiations. Mechanical test results of the irradiated HT-9 steel obtained from previous fast reactor and fusion programs are summarized along with the information of irradiated microstructure. This review can serve as a starting point for additional investigations on the in-core applications of ferritic/martensitic steels in advanced nuclear reactors.

• KSBB Journal
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• v.26 no.2
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• pp.177-181
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• 2011

This study was conducted to investigate the effects of gamma irradiation on the change of volatile flavor compounds of raw oyster and its cooking drips using headspace methods. Major volatile flavor compounds of the raw oyster were identified as methylthiomethane and 1,5-hexadiene. When the raw oyster was irradiated at the dose of 5 kGy, 1-pentane was newly detected. On the other hand, 9 compounds including N-methoxyformaldehyde were identified as the major volatile compounds of cooking drips from oyster. Among them, N-methoxyformaldehyde contents in cooking drip was decreased by the gamma irradiation. By the gamma irradiation above 30 kGy, new heterocyclic compounds was found in oyster cooking drips. Therefore, the amount of volatile flavor compounds in the raw oyster and cooking drips were changed by gamma irradiation, and these results could be potentially used in the seasoning industry.

• Food Science and Biotechnology
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• v.16 no.1
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• pp.138-141
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• 2007

The aim of this study was to investigate the effect of irradiation treatment on the inactivation of pathogens in ready-to-use cooked carrot. The pathogens tested were Salmonella typhimurium, Escherichia coli, Staphylococcus aureus, and Listeria inocua. Following the inoculation of these organisms into cooked carrot (about $10^6-10^8\;CFU/g$), the growth of each was inhibited due to irradiation for 24 hr of storage at $20^{\circ}C$. S. typhimurium and E. coli inoculated into cooked carrot were not detected following irradiation with 3 kGy. S. aureus and L. inocua inoculated into the cooked carrot decreased by 5 logs (CFU/g) following 2 kGy irradiation. The range of $D_{10}$ values was from 0.30-0.50. The Hunter color, $L^*-,\;a^*-$, and $b^*-values$, and the hardness of the cooked carrot were not effected by irradiation treatment. The sensory score of irradiated cooked carrot was not statistically different from that of non-irradiated samples (p>0.05). These results indicate that low dose irradiation can enhance the microbial safety and extend the shelf-life of ready-to-eat foods such as cooked carrot.

• Carbon letters
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• v.16 no.1
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• pp.41-44
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• 2015

We report the preparation of sulfonated reduced graphene oxide (SRGO) by the sulfonation of graphene oxide followed by radiation-induced chemical reduction. Graphene oxide prepared by the well-known modified Hummer's method was sulfonated with the aryl diazonium salt of sulfanilic acid. Sulfonated graphene oxide (SGO) dispersed in ethanol was subsequently reduced by ${\gamma}$-ray irradiation at various absorbed doses to produce SRGO. The results of optical, chemical, and thermal analyses revealed that SRGO was successfully prepared by ${\gamma}$-ray irradiation-induced chemical reduction of the SGO suspension. Moreover, the electrical conductivity of SRGO was increased up to 2.94 S/cm with an increase of the absorbed dose.

• Journal of Plant Biotechnology
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• v.46 no.2
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• pp.88-96
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• 2019

Terpenes constitute a large class of secondary metabolites in plants. The Oryza sativa terpene synthase is a vital gene in plant defense response. In this study, the molecular and physiological functions of Oryza sativa terpene synthase 30 (OsTPS30, LOC_Os08g07080) were investigated after exposure of the seeds and plants to gamma-rays. The OsTPS30 expression was slightly induced at 200 Gray (Gy), but was significantly induced at 400 Gy. The total terpenoid was synthesized more in OsTPS30-overexpressing (OX-OsTPS30) Arabidopsisthaliana plants than in wild-type (WT) plants. The OX-OsTPS30 plants exhibited resistance to gamma-rays, as compared to WT. The OX-OsTPS30 plants had significantly increased height and weight after gamma irradiation. Additionally, the activity of antioxidant enzymes was increased more in OX OsTPS30 plants than in WT plants after gamma irradiation. Furthermore, the OsTPS30-GFP fusion protein was mostly localized in the chloroplast, suggesting that OsTPS30 is putative MEP pathway-related terpene synthase.

• Food Science and Preservation
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• v.15 no.3
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• pp.377-384
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• 2008

The gamma irradiation process was performed to prolong a shelf-life of peaches and the effects of a gamma irradiation on the nutritional, physiochemical and sensory characteristics of peaches were evaluated during a post-irradiation storage at $4^{\circ}C$ and $25^{\circ}C$. Nutritional, physiochemical and sensory characteristics of peaches were stable at 1 kGy of an irradiation, a recommended dose for fruits and vegetables by CODEX, and the viable cell counts of contaminated microorganisms were reduced by 2 decimal reduction, at this dose. After a 1-week storage at ambient condition, the microbiological quality of the 1 kGy irradiated peach was stable, while all the non-irradiated peaches were deteriorated Furthermore, cold storage enhanced the shelf-life of the gamma irradiated peach and the nutritional and physiochemical characteristics of the peaches were comparatively stable up to 6 weeks. Right after gamma irradiation, the sensory evaluation results were not different in any of the samples, and the sensory quality of the irradiated peaches was adequate for a 4-week storage at $4^{\circ}C$. Our results suggested that gamma irradiation at 1 kGy can be used to enhance the shelf-life of peach without a significant loss in the quality attributes, especially upon cold storage after radiation treatment.