• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.261-262
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• 2009

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2009년도 춘계학술대회 논문집
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• pp.533-534
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• 2009

• 지질공학
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• 제30권4호
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• pp.577-588
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• 2020

일부 암석의 우라늄 함량이 높은 것으로 알려진 옥천층군 지역의 유효선량을 파악하기 위하여 휴대용 감마선분광분석기를 이용하여 421개 지점에서 지표방사능(40K, eU, eTh)을 측정하였다. 연구지역을 5개의 지질(og1, og2, og3, og4, 화성암)로 구분했을 때 지질별 지표방사능 강도에는 큰 차이가 없었다. 전체 421 암석의 40K, eU, eTh의 함량은 각각 0.7~10.3% (평균 5.2%), 0.6~287.0 ppm (평균 8.5 ppm), 4.0~102.4 ppm (평균 31.3 ppm) 을 보였다. 방사능강도로부터 구한 연구지역의 흡수선량은 28.84~1,714.5 nGy/h의 범위로서(평균 195.4 nGy/h) 지질별 평균값 최저는 og1의 166.3 nGy/h, 최고는 og2의 233.3 nGy/h(중앙값은 198.1 nGy/h였다. 흡수선량으로부터 구한 연구지역의 옥외 유효선량은 0.04~2.10 mSv/y (평균 0.24 mSv/y)의 범위이며 함 우라늄층이 협재된 og2에 위치한 4개 지점을 제외하면 옥외 유효선량이 1 mSv/y를 넘는 지점은 없었다.

• Journal of Radiation Protection and Research
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• 제41권4호
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• pp.378-383
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• 2016

Background: Radiation dose rates in PRIDE facility is evaluated quantitatively for assessing radiation safety of workers because of large amounts of depleted uranium being handled in PRIDE facility. Even if direct radiation from depleted uranium is very low and will not expose a worker to significant amounts of external radiation. Materials and Methods: ORIGEN-ARP code was used for calculating the neutron and gamma source term being generated from depleted uranium (DU), and the MCNP5 code was used for calculating the neutron and gamma fluxes and dose rates. Results and Discussion: The neutron and gamma fluxes and dose rates due to DU on spherical surface of 30 cm radius were calculated with the variation of DU mass and density. In this calculation, an imaginary case in which DU density is zero was added to check the self-shielding effect of DU. In this case, the DU sphere was modeled as a point. In case of DU mixed with molten salt of 50-250 g, the neutron and gamma fluxes were calculated respectively. It was found that the molten salt contents in DU had little effect on the neutron and the gamma fluxes. The neutron and the gamma fluxes, under the respective conditions of 1 and 5 kg mass of DU, and 5 and $19.1g{\cdot}cm^{-3}$ density of DU, were calculated with the molten salt (LiCl+KCl) of 50 g fixed, and compared with the source term. As the results, similar tendency was found in neutron and gamma fluxes with the variation of DU mass and density when compared with source spectra, except their magnitudes. Conclusion: In the case of the DU mass over 5 kg, the dose rate was shown to be higher than the environmental dose rate. From these results, it is concluded that if a worker would do an experiment with DU having over 5 kg of mass, the worker should be careful in order not to be exposed to the radiation.

• Nuclear Engineering and Technology
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• 제12권3호
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• pp.171-179
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• 1980

중성자 및 감마선에 대한 선량율 환산인자(flux-to-dose-rate conversion factors)를 최대흡수선량 개념을 근거로 하여 계산하였다. 중성자 및 감자선에 대한 선량율 군산인자는 에너지 범위가 각각 2.5$\times$$10^{-8}$ 20MeV 및 0.01-15MeV에 대하여 계산하였다. 이제까지 선량율 환산인자는 단일에너지에 대한 값이 였었는데 본 연구에서는 유사인체조직 (phantom)내에서 방사선의 에너지 분포가 직선적이 아니라고 가정하여 계산되었다. 특히 DLC-23, DLC-27, DLC-31 등 핵정수 자료의 각 근에 적합한 선량율 환산인자를 결정하였다는 점이 특색이다. 결과적으로 ANSI N666에 있는 값과 본 연구에서 계산된 값이 잘 일치된다는 것을 확인하였고, 본 결과는 어떤 방사선장에서도 중성자나 감마선 선량율 분포를 계산하는데 이용될 수 있고, 방사선 차폐해석, 방사선방어, radiation dosimetry 등에 필요한 값이 될 것이다.

• 환경생물
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• 제17권3호
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• pp.257-261
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• 1999

저선량 방사선 조사가 땅콩 “팔팔” 품종 종자의 발아율과 초기생육 및 수량에 미치는 효과를 알아보고자 ${\gamma}$선을 0.5~20.0 Gy 까지 조사하여 포장에 직파재배하였다. 땅콩 종자의 발아율은 저선량 조사에 의해 별다른 효과가 없었으나 유묘초장은 저선량 조사구에서 다소 양호하였다. 수량구성요소 중협수와 종실수 및 종자수량은 12.0 Gy 조사구에서 가장 높았으며, 대조구에 비해 각각 27%와 17% 및 19% 유의성있게 증가하였다. 100립중은 4.0 Gy 조사구가 87.2g으로 대조구의 78.3g에 비해 11%정도 증가하여 저선량 조사에 의해 땅콩 수량이 유의성있는 증가효과를 보였다.

• 방사선산업학회지
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• 제8권2호
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• pp.89-95
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• 2014

This study was conducted to determine the optimal dose of gamma-ray on the growth and nucleus DNA damage for mutation breeding in licorice. Gamma-rays irradiated to dry seeds with various doses (0 to 1000 Gy). Significant decreases in germination rate (%), survival rate (%) and growth characteristics (plant height, number of leaves, root length and fresh weight) were observed by dose of increased. $LD_{50}$ (lethal dose) was approximately 400 Gy to 500 Gy. Also, reduction doses ($RD_{50}$) of plant height, number of leaves, root length and flash weight were 428 Gy, 760 Gy, 363 Gy and 334 Gy, respectively. It is supplest that the optimal dose of gamma irradiation for licorice mutation induction might be about 400 Gy in this study. We also conducted comet assay to observe nucleus DNA damage due to gamma irradiation. In comet assay, a clear difference was identified over 300 Gy treatments. With increasing doses of gamma-ray in the range of 100 to 1000 Gy, the rate of head DNA was decreased significantly from 92.88% to 73.09%. Tail length(${\mu}m$) was increased as the dose of increased over 300 Gy. Growth characteristics (Germination rate, Survival rate, plant height, number of leaves, root length and fresh weight) were highly negatively ($P{\leq}0.01$) correlated with dose. While the tail length was highly positively ($P{\leq}0.01$) correlated with dose.

• Journal of Pharmaceutical Investigation
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• 제23권3호
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• pp.145-153
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• 1993

Retaining a drug in the stomach by some means is sometimes necessary to extend the G1 absorption time of the drug more than 6-8 hrs. Hydrogel has often been examined for its feasibility as a dosage form, so called platform, that could be retained in the stomach due to its excellent swelling properties in the gastric fluid. In this study, polyvinylpyrrolidone (PVP) hydrogel crosslinked by albumin or acrylated albumin was synthesized in a tablet form and evaluated for its possibility as the platform. The synthesis of the hydrogel was performed by $^{60}Co\;{\gamma}-ray$ irradiation of N-vinyl-2-pyrrolidone (monomer) in the presence of a crosslinking agent: aqueous solution of albumin or acrylated albumin. Synthetic conditions such as radiation dose, dose rate and concentration of crosslinking agent were varied in order to optimize the swelling and mechanical properties of the hydrogels. Degree of swelling of albumin-crosslinked PVP (Al-PVP) was highly dependent on radiation dose, dose rate and albumin concentration: it was decreased as they increased. On the other hand, that of acrylated albumin-crosslinked PVP (Acryl-PVP) was almost independent on them except dose rate: it was decreased as the radiation dose rate increased. The compressive strength of the two hydrogels was decreased as the dose rate increased. Digestion of both PVP in artificial gastric fluid containing pepsin was delayed by the ${\gamma}-ray$ irradiation. In conclusion, Al-PVP and Acry-PVP with diverse swelling and mechanical properties could be obtained by controlling synthetic conditions, mainly the irradiation dose rate.

• 한국환경농학회지
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• 제17권4호
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• pp.346-351
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• 1998

방사선 hormesis 효과를 알아보기 위하여 저선량의 방사선을 조사한 후 파종자의 발아양상을 비교하였다. 흥농종묘(주)에서 분양받은 1997년산 '온천'파종자는 대조구에 비해 저선량의 방사선이 조사구에서 약 10%정도 증가된 발아율 양상을 보였으며, 기내배양에서도 마찬가지로 8 Gy 조사구에서 약 10%정도 증가되는 것을 알 수 있었다. 중앙종묘(주)로부터 분양받은 1992년산 '석창외대'파종자의 경우 대조구에서는 약 42.7%의 발아율을 보인 반면 4Gy가 조사된 처리구에서는 약 78.0%까지 발아율이 증가하는 것으로 나타났다. 전반적으로 최적의 비옥토양에서 보다는 비경작지에서 방사선 유익효과가 증가되는 양상을 보였다. 흡습지에서의 발아율 양상은 대조구의 발아율이 22%로 매우 저조한 반면, 1 Gy 조사구에서는 38%까지 발아율이 증가되어 약 16%정도 증가율을 보였다. Paper towel을 이용한 발아율 실험에서 역시 1Gy 조사구에서 발아율이 증가되는 경향을 보였는데 역시 대조구에 비해 1 Gy 조사구에서 약 10% 정도 증가하는 양상을 보였다. 발아율이 증가되었던 저선량 방사선 조사구의 전기전도도를 조사해 본 결과 대조구에 비해 낮아지는 경향을 보였다. 결론적으로 1Gy에서 10Gy정도의 저선량 방사선 수준에서 파종자의 발아율 증가효과가 나타나는 것으로 사료된다.

• Journal of Radiation Protection and Research
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• 제30권4호
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• pp.167-174
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• 2005

The concentrations of natural and artificial radionuclides in soil and gamma ray dose rate in air at 233 locations in Korea have been determined. The national mean concentrations of $^{232}Th,\;^{226}Ra,\;^{40}K,\;^{137}Cs\;and\;^{90}Sr$ in soil were $60{\pm}31,\;33{\pm}14,\;673{\pm}238,\;35{\pm}9.3\;and\;5.0{\pm}3.4\;Bq\;kg^{-1}$, respectively. The mean gamma-ray dose rate at 1 m above the ground was $7918\;nGy\;h^{-1}$. $^{137}Cs$ concentration had highly significant correlation with organic matter content and cation exchange capacity. $^{90}Sr$ concentration had slightly coherent with pH. The results have been compared with other global radioactivity and radiation measurements.