• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.2 no.3
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• pp.155-164
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• 2004

Advanced spent fuel Conditioning Process(ACP) project which is under development for efficient spent fuel management has finished process feasibility study and is preparing $\alpha$-${\gamma}$ type hot cell construction for process experimentation. Radiation dose evaluation for the radioactive nuclides were preliminarily performed for normal operation and accident case with the basic concept design report, the meteorological data and the recent site specific data. According to the production and release rate of nuclides, dose evaluations for residents around facility were performed. The evaluation result shows a safe margin for regulation limits and SAR(Safety Analysis Report) limit of IMEF(Irradiated Material Examination Facility) where this facility will be constructed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.274-278
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• 2002

Surface finishing is still indispensable for most rapid prototyping (RP) processes because of the inherent stair-stepped surface and shrinkage of the parts. These problems can be minimized in the $VLM-_ST$ Process, because it uses expandable polystyrene foam sheets, each of which has a thickness of3.9 mm and a linear-interpolated side slope. The use of thick layers, however, limits the process capability of constructing fine details. This study focuses on the design of post-processing tool for fine details of $VLM-_ST$ parts and investigation of thermal characteristics during EPS foam cutting using the post-processing tool. To calculate the heat flux from the tool into the foam sheet, the tool was modeled as a heat source of radiation for finite element analysis. Results of the analysis agreed well with those of the experiment.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.26 no.1
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• pp.1-10
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• 2016

Objectives: The aim of this study is to review the results of exposure to chemicals and to extremely low frequency(ELF) magnetic fields generated in wafer fabrication operations in the semiconductor industry. Methods: Exposure assessment studies of silicon wafer fab operations in the semiconductor industry were collected through an extensive literature review of articles reported until the end of 2015. The key words used in the literature search were "semiconductor industry", "wafer fab", "silicon wafer", and "clean room," both singly and in combination. Literature reporting on airborne chemicals and extremely low frequency(ELF) magnetic fields were collected and reviewed. Results and Conclusions: Major airborne hazardous agents assessed were several organic solvents and ethylene glycol ethers from Photolithography, arsenic from ion implantation and extremely low frequency magnetic fields from the overall fabrication processes. Most exposures to chemicals reported were found to be far below permissible exposure limits(PEL) (10% < PEL). Most of these results were from operators who handled processes in a well-controlled environment. In conclusion, we found a lack of results on exposure to hazardous agents, including chemicals and radiation, which are insufficient for use in the estimation of past exposure. The results we reviewed should be applied with great caution to associate chronic health effects.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.596-600
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• 2003

The Advanced spent fuel Conditioning Process(ACP) is under development for the effective management of spent fuel which had been generated in nuclear plants. The ACP needs a hot cell where most operations will be peformed. To give priority to the environment safety, radiation doses evaluation for the radioactive nuclides were preliminarily peformed in both normal operation and accident case. The evaluation result shows a safe margin for regulation limits and SAR limit of IMEF where this facility will be constructed.

• Microbiology and Biotechnology Letters
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• v.33 no.3
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• pp.222-225
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• 2005

Stimulatory effects of near infra-red (NIR) rays radiation have been studied within the limits of photosynthesis, phototaxis, and photodermatology. While most of these studies have been done by direct NIR radiation, we investigated the effects of the NIR rays-treated materials on microbial growth. NIR in wavelength of 1,400${\~}$1,700 nm was applied for different kind of materials. Under fast growing conditions in rich media, materials treated with the NIR rays or not did not show any differences in growth of microorganisms. However, under slow growing conditions in minimal media, data showed that NIR rays-treated cloths and hygienic bands affect negatively on the growth of bacteria (Salmonella enteritidis) and fungi (Candida albicans). In addition, it was estimated that the effect of NIR rays on bacterial growth is kept going on S. enteritidis.

• Journal of Radiation Industry
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• v.11 no.3
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• pp.139-144
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• 2017

To evaluation of clinical usefulness for B1+RMS limits, we compared image quality of Routine, Specific absorption rate (SAR) and Root mean square (RMS) protocol. 5 volunteers underwent Magnetic Resonance Imaging (MRI) scan of the brain using three different protocols. We draw Region of interest ROI in cortex, white matter, gray matter, putamen and thalamus of axial plan. Signal to noise ratio (SNR) were evaluated in each area and Contrast to noise ration (CNR) were evaluated between white matter and gray matter. Qualitative evaluation was used to score each ROI. B1+RMS is confirmed its usefulness compared to conventional SAR standard on the aspect of improvement of image quality, reduction of scan time and easy adjusting parameter.

• Journal of Microbiology and Biotechnology
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• v.31 no.4
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• pp.630-636
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• 2021

Glabridin, a compound of the flavonoid, has shown outstanding skin-whitening and anti-aging properties, but its water insolubility limits its wide application. Therefore, glabridin liposome (GL) has been developed to improve its poor bioavailability, while there are few studies to evaluate its amelioration of UVB- induced photoaging. This study is performed to investigate the amelioration of GL against UVB- induced cutaneous photoaging. The prepared GL has a spheroidal morphology with an average diameter of 200 nm. The GL shows lower cytotoxicity than glabridin, but it has a more effective role in inhibition of melanin. Moreover, the application of GL can effectively relieve UV radiation induced erythema and leathery skin, associated with the down-regulated expression of inflammatory cytokines (TNF-α, IL-6 and IL-10). Taken together, these results demonstrate that GL has potentials as topical therapeutic agents against UVB radiation induced skin damage through inhibiting inflammation.

• Nuclear Engineering and Technology
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• v.55 no.5
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• pp.1757-1762
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• 2023

Radiological hazards from external exposure of naturally occurring radioactive materials (NORM) scales residues, generated during the extraction process of oil and gas production in southern Algeria, are evaluated. The activity concentrations of ²²⁶Ra, ²³²Th, and ⁴⁰K were measured using high-purity gamma-ray spectrometry (GeHP). Mean activity concentration of ²²⁶Ra, ²³²Th and ⁴⁰K, found in scale samples are 4082 ± 41, 1060 ± 38 and 568 ± 36 Bq kg^-1, respectively. Radiological hazard parameters, such as radium equivalent (Ra_eq), external and internal hazard indices (H_ex, H_in), and gamma index (I_γ) are also evaluated. All hazard parameter values were greater than the permissible and recommended limits and the average annual effective dose value exceeded the dose constraint (0.3 mSv y^-1). However, for occasionally exposed workers, the dose rate of 0.65 ± 0.02 mSv y^-1 is lower than recommended limit of 1 mSv y^-1 for public.

• Nuclear Engineering and Technology
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• v.56 no.2
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• pp.707-714
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• 2024

Different degrees of natural radioactivity found in quartz can have negative consequences on health. Quartz vein along the investigated Abu Ramad area, Egypt, had its natural radioactivity assessed. The HPGe spectrometer was used to determine the role played by the radionuclides ²³⁸U, ²³²Th, and ⁴⁰K in the gamma radiation that was emitted, and the results showed that these concentrations are 484.64 ± 288.4, 36.8 ± 13.1 and 772.2 ± 134.6 Bq kg^-1 were higher than the corresponding reported global limits of 33, 45, and 412 Bq kg^-1 for each radionuclide (²³⁸U, ²³²Th, and ⁴⁰K). Among the radiological hazard parameters, the excess lifetime cancer risk (ELCR) is estimated and it's mean value of ELCR (1.2) is higher than the permissible limit of 0.00029. The relationship between the radionuclides and the associated radiological hazard characteristics was investigated based on multivariate statistical methods including Pearson correlation, principal component analysis (PCA), and hierarchical cluster analysis (HCA). According to statistical research, the radioactive risk of quartz is primarily caused by the ²³⁸U, ²³²Thand ⁴⁰K. Finally, applying quartz to building materials would pose a significant risk to the public.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2239-2246
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• 2024

The present study aimed to assess the radioactive hazards associated with the application of granitoid rocks in building materials. An HPGe spectrometer was used to detect the levels of the radioactive elements uranium-238, thorium-232, and potassium-40 in the granitoid rocks. The results showed that the levels of these elements were lower (38.32 < 33 Bq kg^-1), comparable (47.19-45 Bq kg^-1) and higher (992.26 ≫> 412 Bq kg^-1) than the worldwide limits for ²³⁸U, ²³²Th, and ⁴⁰K concentration, respectively. The exposure to gamma radiation of granitoid rocks was studied by various radiological hazard variables like the absorbed dose rate (D_air), the outdoor and indoor annual effective dose (AED_out and AED_in), and excess lifetime cancer risk (ELCR). A variety of statistical methods, including Pearson correlation, principal component analysis (PCA), and hierarchical cluster analysis (HCA) was used, to study the relationship between the radioactive elements and the radiological hazards. According to statistical analysis, the main radioactive risk of granitoid rocks is contributed to by the elements uranium-238, thorium-232, and potassium-40. Granitoid rocks can be applied in building materials, but under control to prevent risk to the public.