• Journal of Korean society of Dental Hygiene
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• v.17 no.5
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• pp.721-733
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• 2017

Objectives: This study was conducted to help reduce the anxiety about dental radiation exposures of people and to provide a way to instill proper awareness of dental radiation. Methods: To fulfill the research aim, this study conducted a survey to 330 subjects who are 20 years old or over living in Seoul and Gyeonggi-do during the month of December 2016. The collected data were analyzed using frequency analysis, t-test, one-way ANOVA, Pearson's correlation coefficient and multiple regression analysis among others. Results: As a result of examining the correlation between the anxiety of dental radiography and the correlations between the variables showed that the knowledge of radiation knowledge and the need for radiography (r=0.186, p<0.01), thinking about shooting (r=0.137, p<0.05), and the effectiveness of wearing protective equipment (r=0.120, p<0.01), showing statistically significant differences. As a result of examining the factors influencing anxiety of dental radiography among adults, high awareness of the need for dental radiography (p<0.01), the more the idea of dental anxiety in dental radiography is radiography showed higher (p<0.01). Conclusions: It seems proper that adequate dental radiography requires adequate explanation about it to patients, wearing of protective equipment, and appropriate dental radiation safety education.

• Journal of the Korean Physical Society
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• v.73 no.9
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• pp.1263-1268
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• 2018

Three different ice core samples from Antarctica were analyzed to identify activity concentrations of radioactive isotopes. Tracking migration of radioactive isotopes to Antarctica can provide a key clue to understand global environmental changes caused by radiation exposures because the Antarctic ice cores can preserve unique characteristics of various environmental conditions. We are particularly interested in the $^{137}Cs$ nucleus, because it is closely related to radiation exposure from nuclear power plant accidents and nuclear bomb tests. With its half life of $30.17{\pm}0.03$ years, $^{137}Cs$ can also be used to assess the age of sedimentation occurring after around the year 1945. We selected three ice core samples, called Tarn8, Styx27, and H25, from different time periods; the Tarn8 sample is known to be from earlier than ~ 1000 AD, the Styx27 sample is approximately from the year 1945, and the H25 sample is from the year 2012. Radioactive isotope measurements of the ice core samples were performed using a 100% HPGe detector at Cheongpyeong Underground Radiation Laboratory (CURL). We measured the activity of $^{137}Cs$ in the H25 sample to be $0.98{\pm}0.82mBq/kg$. Although the activity has a large uncertainty mainly due to the limited sample quantity, the $^{137}Cs$ isotopes in the Antarctic ice core were measured for the first time in Korea.

• Nuclear Engineering and Technology
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• v.54 no.4
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• pp.1431-1438
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• 2022

In this study, natural radioactivity concentrations and dosimetric values of fly ash samples were evaluated for the landfill area of the coal-fired power plant (CFPP) complex at Binh Thuan, Vietnam. The average activity concentrations of ²³⁸U, ²²⁶Ra, ²³²Th and ⁴⁰K were 93, 77, 92 and 938 Bq kg^-1, respectively. The average results for radon dose, indoor external, internal, and total effective dose equivalent (TEDE) were 5.27, 1.22, 0.16, and 6.65 mSv y^-1, respectively. The average emanation fraction for fly ash were 0.028. The excess lifetime cancer risks (ELCR) were recorded as 20.30×10^-3, 4.26×10^-3, 0.62×10^-3, and 25.61×10^-3 for radon, indoor, outdoor exposures, and total ELCR, respectively. The results indicated that the cover of shielding materials above the landfill area significantly decreased the gamma radiation from the ash and slag in the ascending order: Zeolite < PVC < Soil < Concrete. Total dose of all radionuclides in the landfill site reached its peak at 19.8 years. The obtained data are useful for evaluation of radiation safety when fly ash is used for building material as well as the radiation risk and the overload of the landfill area from operation of these plants for population and workers.

• Journal of Radiation Industry
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• v.17 no.1
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• pp.61-67
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• 2023

A Study on the Introduction of Dose Constraints for Occupational Exposures: Focusing on Experts' Opinions by Field of Radiation Industry. The International Commission on Radiological Protection suggests Justification, Optimization, and Dose Limits as the three principles of radiological protection, among which, as a means of protection optimization, ICRP 103 recommends to set dose constraints. In this study, opinions are collected from experts in each category of radiation industries for stakeholder participation to qualify dose constraints. A guidance and questionnaire for analyzing the dose constraints have been developed for their collection, and opinions were collected from radiation protection experts in selected categories. 20 out of 22 experts, consisted with 91%, have assessed the dose constraints setting is necessary, and 2 experts, consisted with 9%, assessed it is unnecessary. The average of dose constraint presented by experts for RI production institutions is to be the highest level of 15.3 mSv, and light-water reactors (14.6 mSv), non-destructive inspection (14.4 mSv), heavy-water reactor and medical institutes (13.9mSv) is to be above the overall average dose constraint. In case of public institutions, the average dose constraint is to be 8.6mSv, and research institutions (8.8mSv), educational institutions (9.6 mSv), waste disposal sites (9.7 mSv), and general industries (10.6 mSv) are resulted to below the overall average dose constraint. As for the means of setting dose constraints, 8 experts out of 22 suggested setting dose constraints for each specific industry or task. And, 5 experts especially suggest setting dose constraints for the specific groups with relatively high exposure, such as workers with above the record levels. As a countermeasure for workers who exceed the dose constraints, 15 experts out of 22 expressed that the cause analyses for them and preparation for a plan of reducing them are necessary.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.507-513
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• 2010

This paper is described the analysis of time-varying low-frequency electric magnetic field emitted from electric rolling stocks fed by VVVF inverter, in reference to allowable magnitude for exposures to time-varying electromagnetic field issued by International Commission on Non-Ionizing Radiation Protection(ICNIRP). The level of the magnetic field strength was measured, in reference to the standard for occupational environments, which takes into account the public person's protection against the excessive emission of the low-frequency magnetic field, 5 Hz ~ 2 kHz.

• The Korean Journal of Ceramics
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• v.3 no.3
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• pp.213-217
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• 1997

In this paper, the imparct of X-ray and plasma process-induced-damages to La doped Lead Zirconate Titanate (PLZT, (Pb1-xLa)(Zr0.5Ti0.5)O3) capacitor characteristics have been investigated from the viewpoint of gigabit scale dynamic random access memory (DRAM) applications. Plamsa damage causes asymmetric degradation on hysteresis characteristics of PLZT films. On the other hand, X-ray damage results in a symmetrical reduction of charge storage densities (Qc's) for both polarities. As La concentration increases in the films, the radiation hardness of PLZT films on X-ray and plasma exposures is improved. It is observed that the damaged devices are fully recovered by thermal annealing under oxygen ambient.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2017.11a
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• pp.111-112
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• 2017

Radon has been considered the greatest source of exposure within the total radiation exposure of the human body. xposure from radon, which exists in indoor air quality, lacks public perception, Radon, which exists anywhere on earth, is not regarded as a state of attention even if it is above the average level. Indoor radon exposure situations are not intentionally introduced, and essentially the attention and responsibilities of radon exposures are assumed to be in indoor occupants. So, these are caused by common uranium and thorium scattering on Earth, and are brought into the building by fine cracks or exposed indicators of the buildings. Therefore, this study aims to reduce the risk of radon rays and reduce radon, which induces diseases caused by breathing in the body of indoor air pollutants and emitting diseases by emitting alpha rays from the radon gas.

• Journal of the Korean Society of Safety
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• v.26 no.5
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• pp.23-26
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• 2011

The aim of this paper is to evaluate noise characteristics of an electric power driven hammer. These investigation and analysis were made according to the ISO 1680/1 and MIL-STD 7410-1 and lead-wrapping experiment method that was used to identify the principal noise sources and analyze its noise. Hammer generates loud noise and it irritates and affects many people. Repeated exposures to loud noise can lead people to permanent hearing loss. Based on the contribution analysis, we confirm that the striker part is a major noise source and it has directional noise radiation pattern, which is left and right.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.21 no.2
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• pp.247-253
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• 2023

According to NSSC Notice No. 2021-10, safety analysis needs to be introduced in the decommissioning plan. Public and occupational dose analyses should be conducted, specifically for unexpected radiological accidents. Herein, based on the risk matrix and analytic hierarchy process, the method of selecting accident scenarios during the decommissioning of nuclear power plants has been proposed. During decommissioning, the generated spent resin exhibits relatively higher activity than other generated wastes. When accidents occur, the release fraction varies depending on the conditioning method of radioactive waste and type of radioactive nuclides or accidents. Occupational dose analyses for 2 (fire and drop) among 11 accident scenarios have been performed. The radiation doses of the additional exposures caused by the fire and drop accidents are 1.67 and 4.77 mSv, respectively.

• Journal of Pharmaceutical Investigation
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• v.22 no.3
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• pp.35-47
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• 1992

Hydrogel coated ring shaped ocular inserts (containing the antibiotic, tylosin tartrate) were used in an evaluation of the effectiveness of polymeric ocular drug release devices for treating infectious bovine keratoconjunctivitis. The in vivo experiments represent the first experiments using hydrogel ocular inserts containing an antibiotic for treating infectious bovine keratoconjunctivitis. In the infection tests, ten calves. were challenged with $2.4{\times}10^8{\sim}1.6{\times}10^9$ Moraxella bovis (a bacterium) colonies per eye following two ten minute ultraviolet radiation eye preconditioning exposures. Ninety five percent of the eyes (19 of 20 eyes) were successfully infected by this method. All infected eyes were monitored for the presence of the bacteria quantitiatively, and clinical observations were made for 14 days. The test was performed by three consecutive steps: 1) inoculation with 2 ultraviolet (UV) radiations, 2) growth of bacterial colonies and 3) treatment with medicated ring-shaped devices. The first. bacteriological measurements after 2 UV exposures were performed at day 3 of the tests. At day 7 after inoculation of both eyes of a calf with M. bovis, a medicated or a non-medicated ring-shaped device was inserted into each eye of a calf. The eye receiving the non-medicated ring was taken as a control for comparison with the eye that received a medicated ring. During the next 7 day period following a medicated ring insertion, the number of bacteria in the treated eyes dropped dramatically to negligible levels (0 to 30 colony forming units/swab), while the control eyes which received a non-medicated ring still exhibited a relatively high number of bacteria ($10^3\;to\;10^6$ colony forming units/swab). The number of bacteria was significantly reduced by the antibiotic released from the medicated ocular insert.