• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.2_spc
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• pp.227-235
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• 2020

In this study, we discussed the limitations of gross alpha measurements for the characterization of radioactive wastes produced in nuclear facilities through experimental tests and Monte Carlo N-particle transport simulations. The determination of gross alpha is essential for the disposal of radioactive waste produced in nuclear facilities in Korea. The measurements of gross alpha are easy to perform and yield rapid analytical results, but it cannot be used for quantitative analysis. The error of counting efficiency for gross alpha with various masses of the deposit on planchets using KCl and ²⁴¹Am was determined. The relative deviation of the counting efficiency in samples having the same mass was 20%. Uranium was extracted from the soil through acid leaching and extraction chromatography, and the concentration of U determined by inductively coupled plasma-mass spectrometry (ICP-MS) was compared with the results for gross alpha. The gross alpha was underestimated by 50% compared to the U concentration by ICP-MS. The counting efficiency depended on the energy from the alpha emitters, which differed by up to three times in determination of the counting efficiency depending on the kinds of alpha radionuclides of interest. Therefore, the gross alpha is not compatible with the sum of radioactivity for each alpha emitter and is suitable as a screening method.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2007.05a
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• pp.243-244
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• 2007

• 대한방사선방어학회:학술대회논문집
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• 2009.11a
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• pp.228-229
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• 2009

• Journal of Radiation Protection and Research
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• v.37 no.4
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• pp.226-230
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• 2012

The gross alpha analysis of nasal smear samples for the radiation emergency and the additional follow-up steps were established. Cotton swab sticks using in local hospitals for nasal smear in Korea were used for the verification. The measurement results of standard samples spiked with certified reference source were well agreed within ${\pm}20%$ compared with reference values. The clearance ratio of smear samples conducted with wet smear condition showed higher value. To eliminate the quenching effect of liquid scintillation samples, dry of smear samples should be followed up before counting samples. Based on the measurement results, medical decision levels and internal dose assessment were established for the victims in the beginning of radiation emergency.

• 대한방사선방어학회:학술대회논문집
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• 2009.11a
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• pp.84-85
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• 2009

• Journal of the Korean Society of Food Culture
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• v.10 no.2
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• pp.101-106
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• 1995

The effects of ${\alpha}-rice$ flour on the physicochemical properties of Korean rice cake were investigated. Before cooking, the degree of gelatinization of rice cake without ${\alpha}-rice$ flour was 5.75%, but 16% for adding ${\alpha}-rice$ flour. After cooking, the degree of gelatinization of rice cake were increased from 52% to 85% by adding ${\alpha}-rice$ flour. The L value of rice cake with ${\alpha}-rice$ flour increased, but there was no significant difference in L value between samples. The hardness of rice cake before and after cooking were increased by adding ${\alpha}-rice$ flour whereas after frozen stoarge there was no apparent effect on the color values of rice cake. The water absorption ratio of rice cakes during cooking were increased by addition of ${\alpha}-rice$ flour. Scanning electron photomicrographs revealed that the rice cake with ${\alpha}-rice$ flour has more porous structure with rapid rehydration.

• Journal of Radiation Protection and Research
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• v.17 no.1
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• pp.31-41
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• 1992

A study for the evaluation of selected filter media that need further characterization particularily in the context of alpha measurements of radon progeny has been carried out by investigating physical characteristics and using the alpha spectroscopy. Physical characteristics was investigated by electrostatic charging and mechanical strength of filters, and then pressure drop before and after sampling was tested. Alpha spectroscopy was used to analyze the energy spectra from the deposition of radon progeny into filters. The results of the assessment showed that the newer filter types do not have a great advantage over the 'old standard' Millipore type AA. But Metricel DM-800 is recommended for those situations where electrostatic charging is a problem. Also this method will be used more effective for the evaluation of new developing filters in future.

• Proceedings of the KIEE Conference
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• 2006.07d
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• pp.2177-2178
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• 2006

학습 행동에서의 뇌파 측정은 실시간으로 두뇌 기능 상태를 연구하는데 유용한 연구 방법이며 대뇌의 부위 중 전두엽은 새로움에 대한 지향 반응과 사고 활동에 중요한 역할을 한다. 본 연구에서는 중학교 2학년 학생에게 새로운 시청각 학습 자료를 제시하고 5회의 반복학습이 이루어지는 과정에서의 전두부($Fp_2,Fp_2$)의 뇌파를 측정하고 Fourier, Wavelet 변환을 하여 정량적으로 분석하였다. 주의 집중, 정서 등 인지와 관련지어 특정파의 조절 능력 및 파의 특성을 이용한 여러 연구들을 종합해보면, 기억력, 주의지속과 연관되어 알파파, 베타파와 세타파가 발생되는 것을 볼 수 있다. 이 중 알파파는 기존의 뇌 상태를 동기화시키고 주의나 기억의 과정에 영향을 미칠 수 있는 것으로 증명되었다. 본 논문에서는 신호 처리에 높은 효율을 보이는 Wavelet 변환을 이용하여, 학습이 됨에 따라 변화하는 EEG 신호 가운데 알파파의 패턴과 활성도를 분석하고자 한다.

• Korean Journal of Clinical Laboratory Science
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• v.52 no.3
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• pp.253-260
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• 2020

Alzheimer's disease (AD) is a chronic and progressive neurodegenerative disease that can be described by the occurrence of dementia due to a decline in cognitive function. The disease is characterized by the formation of extracellular and intracellular amyloid plaques. Amyloid beta (Aβ) is a hallmark of AD, and microglia can be activated in the presence of Aβ. Activated microglia secrete pro-inflammatory cytokines. Furthermore, S100A9 is an important innate immunity pro-inflammatory contributor in inflammation and a potential contributor to AD. This study examined the effects of metformin and α-LA on the inflammatory response and NLRP3 inflammasome activation in Aβ- and S100A9-induced BV-2 microglial cells. Metformin and α-LA attenuated inflammatory cytokines, such as tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). In addition, metformin and α-LA inhibited the phosphorylation of JNK, ERK, and p38. They activated the nuclear factor kappa B (NF-κB) pathway and the NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasome. Moreover, metformin and α-LA reduced the marker levels of the M1 phenotype, ICAM1, whereas the M2 phenotype, ARG1, was increased. These findings suggest that metformin and α-LA are therapeutic agents against the Aβ- and S100A9-induced neuroinflammatory responses.

• 대한방사선방어학회:학술대회논문집
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• 2009.04a
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• pp.270-271
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• 2009