• 전기학회논문지
• /
• 제62권10호
• /
• pp.1421-1424
• /
• 2013

The electronic equipment which is exposed to high level pulsed radiation is damaged by Upset, Latchup, and Burnout. Those damages come from the instantaneous photocurrent from electron-hole pairs generated in itself. Such damages appear as losses of a power in military weapon system or as a blackout in aerospace equipment and eventually caused in gross loss of national power. In this paper, we have implemented a RDC(Radiation detection and control module) as a part of the radiation protection technology of the electronic equipment or devices from the pulsed gamma radiation. The RDC, which is composed of pulsed gamma-ray detection sensor, signal processors, and pulse generator, is designed to protect the an important electronic circuits from the a pulse radiation. To verify the functionality of the RDC, LM118s, which had damaged by the pulse radiation, were tested. The test results showed that the test sample applied with the RDC was worked well in spite of the irradiation of a pulse radiation. Through the experiments we could confirm that the radiation protection technology implemented with the RDC had the functionality of radiation protection for the electronic devices.

• Journal of Radiation Protection and Research
• /
• 제6권1호
• /
• pp.8-24
• /
• 1981

This paper presents flux-to-dose-rate conversion factors for neutrons and gamma rays based on the American National Standard Institute(ANSI) N666. These data are used to calculated the dose rate distribution of neutron and gamma ray in radiation fields. Neutron flux-to-dose-rate conversion factors for energies from $2.5{\times}10^{-8}$ to 20 MeV are presented; the corresponding energy range for gamma rays is 0.01 to 15 MeV. Flux-to-dose-rate conversion factors were calculated, under the assumption that radiation energy distribution has nonlinearity in the phantom, have different meaning from those values obtained by monoetiergetic radiation. Especially, these values were determined with the cross section library. The flux-to-dose-rate conversion factors obtained in this work were in a good agreement to the values presented by ANSI. Those data will be a useful for the radiation shielding analysis and the radiation dosimetry in the case of continuous energy distributions.

• 대한수의학회지
• /
• 제55권1호
• /
• pp.21-30
• /
• 2015

The immune system is specifically sensitive to oxidative stress induced by ionizing radiation because of its rapid proliferative activity. For this reason, an instructive immune system is one of the best ways to minimize side effects, such immunodeficiency, of gamma radiation. Over the past few decades, several natural plants with antioxidant and immunomodulatory properties have been identified as adjuncts for nontoxic and successful radiotherapy. Hizikia fusiforme extract (HFE) containing plentiful dietary fiber and fucoidan is known for its instructive antioxidant capacity, immunomodulation abilities, and immune activation. In this study, we determined whether HFE protects radiosensitive immune cells from gamma radiation-induced damage. C57BL/6 mice were irradiated with gamma-ray. The effect of HFE on the ionizing radiation damage of immune cells was then evaluated with an MTT assay, 3H-thymidine incorporation assay, and PI staining. We found that HFE stimulated the proliferation of gamma-ray irradiated immune cells without cytotoxic effects. We also observed that HFE not only decreased DNA damage but also reduced gamma radiation-induced apoptosis of the immune cells. Our results suggest that HFE can protect immune cells from gamma-ray damage and may serve as an effective, non-toxic radioprotective agent.

• 아시안잔디학회지
• /
• 제22권1호
• /
• pp.25-34
• /
• 2008

본 연구는 잔디종자에 감마선을 조사하였을 때 종자 발아율 및 초기 생육을 관찰하여 잔디 종류에 따른 방사선 감수성을 관찰하고 돌연변이 유기를 위한 적정 방사선 선량을 결정하고자 수행되었다. 난지형 잔디인 zoysiagrass, bermudagrass, seashore paspalum과 한지형 잔디인 Kentucky bluegrass, tall fescue, perennial ryegrass, creeping bentgrass를 실험에 사용하였다. 다양한 방사선 선량으로 24시간 처리한 후 발아율 및 신초, 뿌리 길이와 생체중을 조사한 결과 방사선 선량이 증가할수록 발아율 및 초기 생육이 감소하는 것으로 나타났다. 감마선에 의해 생육이 50% 억제되는 반치사선량을 조사한 결과 잔디 종류에 따라 다양하게 관찰됨을 알 수 있었다. 잔디 종류별 반치사선량 ($LD_{50}$)은 zoysiagrass, seashore paspalum, bermudagrass, Kentucky bluegrass, perennial ryegrass, tall fescue, creeping bentgrass 각각 300, 150, 600, 150, 200, 100, 200 Gy로 bermudagrass가 가장 높고, tall fescue가 가장 낮게 나타났다.

• 한국식품영양과학회지
• /
• 제37권3호
• /
• pp.362-366
• /
• 2008

본 연구는 감마선 조사가 재구성 돈육포의 이화학적 및 관능적 품질에 미치는 영향을 파악하고자 0, 3, 5, 7, 10 kGy 선량으로 조사된 재구성 돈육포의 일반성분, 지방산패도, 색도, 전단력 및 관능검사를 실시하였다. 일반성분 분석 결과에서 감마선 조사에 따른 수분, 조단백, 조지방의 함량 및 TBA값의 변화는 없었다. 그러나 색도 측정 결과 적색도인 a값이 유의적으로 증가함을 확인할 수 있었다(p<0.05). 전단력 측정 결과 조사선량이 증가할수록 전단력은 낮아졌으며, 관능검사 결과 모든 조사구에서 유의적인 차이를 보였다(p<0.05). 관능평가에서 기호도는 감마선 조사에 의해 낮아졌다. 따라서 재구성 돈육포에 있어 감마선의 조사는 육색 및 조직감을 개선시킬 수 있는 좋은 수단이나 관능적 개선을 위한 추가적인 연구가 필요하였다.

• 한국원자력학회:학술대회논문집
• /
• 한국원자력학회 1997년도 춘계학술발표회논문집(2)
• /
• pp.566-570
• /
• 1997

The effect of average gamma energy on the external radiation dose has been analyzed. Cloud- and groundshine have been calculated according to the average gamma energy. Monte Carlo integration method was used for the calculation of cloudshine and Romberg quadrature method was adopted for groundshine. The analysis shows that the external gamma exposure is strong]y dependent on the gamma energy and the distribution of radiation sources.

• Rapid Communication in Photoscience
• /
• 제1권1호
• /
• pp.21-24
• /
• 2012

Influence of gamma rays on the cyanobacterium Synechocystis sp. PCC 6803 cells was investigated in terms of a bidirectional hydrogenase, which is encoded by hoxEFUYH genes and responsible for biohydrogen production. Irradiated cells revealed a substantial change in stoichiometry of photosystems at one day after gamma irradiation at different doses. However, as evaluated by the maximal rate of photosynthetic oxygen evolution, maximal photochemical efficiency of photosystem II, and chlorophyll content, net photosynthesis or photosynthetic capacity was not significantly different between the control and irradiated cells. Instead, transcription of hoxE, hoxH, or lexA, which encodes a subunit of bidirectional hydrogenase or the only transcriptional activator, LexA, for hox genes, was commonly enhanced in the irradiated cells. This transcriptional enhancement was more conspicuously observed immediately after gamma irradiation. In contrast, hydrogenase activities were found to somewhat lower in the irradiated cells. Therefore, we propose that transcription of hox genes should be enhanced by gamma irradiation in a LexA-mediated and possibly photosynthesis-independent manner and that this enhancement might not induce a subsequent increase in hydrogenase activities, probably due to the presence of post-transcriptional and/or post-translational regulatory mechanisms.

• 환경생물
• /
• 제22권3호
• /
• pp.472-477
• /
• 2004

본 연구에서는 감마선으로 유도된 돌연변이체들에서 공통으로 발현되는 방사선 관련 유전자들의 발현을 연구하기 위하여, B. lentimorbus WJ5 의 방사선 유도 돌연변이체에서 발현되는 유전자를 DNA microarray로 동시에 탐색하였다. DNA microarray는 B. lentimorbus WJ5 genome을 무작위로 절단하여 2,000 단편으로 구성하였으며, 감마선 $(^{60}/Co)$으로 유도된 7 돌연변이체의 발현을 정량적으로 관찰하였다. 클러스터 분석결과 발현된 408 유전자 중 27개가 감마선 유도 돌연변이체 모두에서 유의하게 발현이 증가되었다. 특히, 복구(mutL, mutM) 에너지 대사 (acsA, sdhB, pgk, yhjB, citB), protease (npr), 산화자극에 대한 환원 (HMM)관련 유전자들이 동시에 증가되었다. 이는 감마선 유도 돌연변이체들에서 자발적인 직/간접 복구 관련 유전자의 발현 증가는 방사선 노출 직후 보이는 stress response와는 다른 현상임을 나타내는 것으로 생각된다.

• Nuclear Engineering and Technology
• /
• 제53권6호
• /
• pp.1991-1999
• /
• 2021

The response changes of the specific growth rate of Lemna minor duckweed was modeled using the logarithms of frond numbers on tritium activity concentration and gamma radiation dose from cobalt 60. The concept of average specific growth rate depends on the general exponential growth pattern, where toxicity is estimated based on the effect on the growth rate. One of the main questions of the effect of the radiation dose on duckweed is how to correlate the effect of beta radiation with the effect of any other radiation for modeling radiation on Lemna minor. Experimental data were extrapolated by utilizing the OECD guidelines. A linear relationship of absorbed dose and activity concentration was obtained for the average dependency growth rate of Lemna minor as D = (0.1257)·A^0.585. The dose rate of gamma irradiation from ⁶⁰Co increases with tritium activity dependence, on the specific growth rate of the Lemna minor duckweed. An increase in the tritium activity causes a decrease in the specific growth rate of the Lemna minor duckweed. It indicates that as the quantity of the beta radiation dose increase in Lemna minor duckweed, a higher quantity of gamma radiation will be required to cause the same effect in the specific growth rate of Lemna minor duckweed. The relation between the inhibition of the Lemna minor seedling growth and gamma and beta radiation dosage agrees roughly with that between the decrease of survival rate or fertility and dosage.

• Toxicological Research
• /
• 제20권2호
• /
• pp.117-122
• /
• 2004

The present study was carried out to establish a short-term teratogenicity study for detecting developmental toxic potential induced by gamma radiation in ICR mice. Pregnant mice were exposed at dose levels of 0, 0.5, 1, 2, or 4 Gy on gestational day 8.5. All dams were subjected to caesarean section on gestational day 10.5 and their embryos were examined for growth, differentiation, and morphological abnormalities. An increase in the number of resorption was found at 4 Gy in a dose-dependent manner. Dose-dependent decreases in the developmental score of yolk sac circulation and olfactory system at above 1 Gy, in the number of somite pairs and developmental score of allantois, optic system, and maxillary process at above 2 Gy, and in the all growth and developmental parameters examined at 4 Gy were found. Various types of morphological abnormalities were seen at dose levels of 0.5 Gy or greater. Characteristic malformations induced by gamma radiation were abnormal axial rotation, hematoma, craniofacial hypoplasia, open neuropore, shortened prosencephalon, kinked somites, irregular somites, swelling, hydropericardium, absent branchial bar, and absent limb bud. Morphological alterations such as hematoma, craniofacial hypoplasia, open neuropore, and kinked somites were noted even in the lowest dose (0.5 Gy). These results indicated that the short-term teratogenicity study established in this study can be a useful tool for not only detecting the developmental toxic potential induced by gamma radiation, but also screening radio-protective agents in ICR mice.