• Journal of Radiation Protection and Research
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• 제26권3호
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• pp.183-190
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• 2001

The activity concentration of primordial radionuclides i.e., $^{238}U$ series, $^{232}Th$ series and $^{40}K$, in soil samples collected from Udagamandalam environment, have been measured by employing NaI (Tl) Gamma ray Spectrometer. The absorbed gamma dose rate has also been simultaneously measured by using both Environmental Radiation Dosimeter at each soil sampling location (ambient gamma dose) as well as from the gamma dose derived from the activity concentration of the primordial radionuclides. The results of activity concentration of each radio nuclides in soil, absorbed dose rate in air due to soil activity and possible cosmic radiation at each location along with human effective dose equivalent for Udagamandalam environment are presented and discussed.

• 방사선산업학회지
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• 제8권2호
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• pp.105-109
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• 2014

This study was conducted to investigate the sensitivity of Arthrobacter sp. PAMC 25486 to various mutagens. ${\gamma}-ray$, UV-ray, Ethyl methane sulfonate (EMS) and hydrogen peroxide ($H_2O_2$) were used as mutagen, and the survival rate of Arthrobacter sp. was measured at various doses of ${\gamma}-ray$ and UV-ray, and concentrations of EMS and $H_2O_2$. Decimal reduction dose ($D_{10}$ value) of Arthrobacter sp. was determined 370 Gy for a gamma irradiation treatment, 0.019 J for a UV ray, 2.5 mM for EMS, and 230 mM for $H_2O_2$. This result will be applied for the development of superior mutant strain of Arctic bacteria producing valuable compounds.

• Nuclear Engineering and Technology
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• 제55권6호
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• pp.1966-1973
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• 2023

Virtual reality technology has been widely used in the field of nuclear and radiation safety, dose rate computing in virtual environment is essential for optimizing radiation protection and planning the work in radioactive-controlled area. Because the CPU-based gamma dose rate computing takes up a large amount of time and computing power for voxelization of volumetric radioactive source, it is inefficient and limited in its applied scope. This study is to develop an efficient gamma dose rate computing code and apply into fast virtual simulation. To improve the computing efficiency of the point kernel algorithm in the reference (Li et al., 2020), we design a GPU-based computing framework for taking full advantage of computing power of virtual engine, propose a novel voxelization algorithm of volumetric radioactive source. According to the framework, we develop the GPPK(GPU-based point kernel gamma dose rate computing) code using GPU programming, to realize the fast dose rate computing in virtual world. The test results show that the GPPK code is play and plug for different scenarios of virtual simulation, has a better performance than CPU-based gamma dose rate computing code, especially on the voxelization of three-dimensional (3D) model. The accuracy of dose rates from the proposed method is in the acceptable range.

• 미생물학회지
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• 제11권2호
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• pp.79-88
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• 1973

In order to investigate the effect of gamma radiation on Salmonella typhi, Ty2, the components of amino acids, proteins, carbohydrates and lipids in irradiated cells were compared with those in unirradiated control cells respectively. The results obtained were as follows ; 1) The inactivation curves of Salmonella typhi with $Co^{60}$ .gamma.-ray irradiation were exponential over a wide range to the irradiated doses. 2) Dose for the inactivation factor of $10^8$ was 94.0 Krad in physiological saline or in phosphate buffered saline, 104.2 Krad in nutrient broth, 220.4Krad in frozen state, 552.0 Krad in dried state, 88.3 Krad in the abundance of oxygen and 188.0 Krad in the deficience of oxygen, respectively. 3) Five consecutive irradiation of Salmonella typhi suspension at the dose of 90 Krad gave no additional increase in resistance. 4) Even at the smallest dose of 500 Krad, compositions of amino acids, proteins, carbohydrates, and lipids were more or less decreased and the distinct banding patterns were also lost possibly due to degradation of the protein molecules.

• KIEE International Transactions on Electrophysics and Applications
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• 제3C권2호
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• pp.48-54
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• 2003

To evaluate the radiation degradation of ethylene propylene rubber (EPR), radiation effects on EPR were investigated by using dielectric analysis and thermal-gravimetric analysis. Permittivity, loss factor, tan$\delta$, and thermal decomposition temperature were observed for ${\gamma}$-ray irradiated EPR. As the radiation dose was increased, the peak temperature of the loss factor and tans of EPR were increased and loss factor and tan$\delta$ at peak temperature were decreased. Activation energies were calculated using loss factor and thermal decomposition for ${\gamma}$-ray irradiated EPR as well. The trends of both calculated activation energies showed the same tendencies as radiation dose was increased.

• 아시안잔디학회지
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• 제22권1호
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• pp.25-34
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• 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.

• 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.

• Nuclear Engineering and Technology
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• 제6권4호
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• pp.239-247
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• 1974

방사선 안전관리의 효과적인 연구를 위해 유사인체 모형을 설계, 제작하였다. 이 모형의 치수는 한국인의 체격과 근사하게 맞추었으며 두께 2.5cm인 포리에칠렌판 35매로 구성되었다. 유사인체모형의 표면에 착용한 열형광 설량계(Disc type TLD)로써 외부 ${\gamma}$-방사선에 의한 신체특정부위의 피폭선량을 측정하였으며, 아울러 깊이에 따른 흡수선량에 대해서 열형광 선량계(micro rod type TLD)로써 측정하여 결정장기 부위의 각단면에 대한 등가선량선을 얻었다. 선량측정은 방사선 작업자의 작업환경조건에 유사하도록 유사인체 모형에 대해 배치하고 여러 입사방항에 대해서 실시하였다. 그 결과 Cs-137, ${\gamma}$-방사선에 대하여 두께 20cm인 유사인체 모형에서의 감쇄는 0.439였으며 이는 보고된 자료들과 잘 일치하였다.

• Journal of Electrical Engineering and Technology
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• 제9권6호
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• pp.2065-2069
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• 2014

The DAC-7512E is a 12-bit digital to analog converter that is low power and a single package with internal buffers. The DAC-7512E takes up minimal PCB area for applications of space power electronics design. The spacecraft mass is a crucial point considering spacecraft launch into space. Therefore, we have performed a TID test for the DAC-7512E 12-bit serial input digital to analog converter to reduce the spacecraft mass by using a low-level Gamma-ray irradiator with $Co^{60}$ gamma-ray sources. The irradiation with $Co^{60}$ gamma-rays was carried out at doses from 0 krad to 100 krad to check the error status of the device in terms of current, voltage and bit error status during conversion. The DAC-7512E 12-bit serial digital to analog converter should work properly from 0 krad to 30 krad without any error.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.437-440
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• 2004

The radiation-induced changes taking place in poly(vinylidene fluoride)(PVDF) exposed to $^{60}Co\;\gamma-ray$ irradiation were investigated in correlation with the applied doses. Samples were irradiated in air at room temperature by $^{60}Co\;\gamma-ray$ to doses in the range of 200 to 1000 kGy. Various properties of the irradiated PVDF were studied using nm, differential scanning calorimetry(DSC) and gel fraction. $^{60}Co\;\gamma-ray$ irradiation was found to induce changes in chemical, thermal, structural properties of PVDF and such changes vary depending on the radiation dose.