검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 16

        1.
        2023.11 구독 인증기관·개인회원 무료
        When the parent radionuclide decays, the progeny radionuclide is produced. Accordingly, the dose contribution of the progeny radionuclide should be considered when assessing dose. For this purpose, European Commission (EC) and International Atomic Energy Agency (IAEA) provide weighting factors for dose coefficient. However, these weighting factors have a limitation that does not reflect the latest nuclide data. Therefore, in this study, we analyzed the EC and IAEA methodology for derivation of weighting factor and used the latest nuclide data from ICRP 107 to derive weighting factors for dose coefficient. Weighting factor calculation is carried out through 1) selection of nuclide, 2) setting of evaluation period, and 3) derivation based on ICRP 107 radionuclide data. Firstly, in order to derive the weighting factor, we need to select the radionuclides whose dose contribution should be considered. If the half-life of progeny radionuclides sufficiently short compared to the parent radionuclide to achieve radioactive equilibrium, or if the dose coefficient is greater of similar to that of the parent radionuclide and cannot be ignored, the dose contribution of the progeny radionuclide should be considered. In order not to underestimate the dose contribution of progeny radionuclides, the weighting factors for the progeny nuclides are taken as the maximum activity ratio that the respective progeny radionuclides will reach during a time span of 100 years. Finally, the weighting factor can be derived by considering the radioactivity ratio and branch fraction. In order to calculate the weighting factor, decay data such as the half-life of the radionuclide, decay chain, and branch fraction are required. In this study, radionuclide data from ICRP 107 was used. As a result of the evaluation, for most radionuclides, the weighting factors were derived similarly to the existing EC and IAEA weighting factors. However, for some nuclides, the weighting factors were significantly different from EC and IAEA. This is judged to be a difference in the half-life and branch fraction of the radionuclide. For example, in the case of 95Zr, the weighting factor for 95mNb showed a 35.8% difference between this study and previous study. For ICRP 38, when 95Zr decays, the branch fraction for 95mNb is 6.98×10-3. In contrast, for ICRP 107, the branch fraction is 1.08×10-2, a difference of 54.7%. Therefore, the weighting factor for the dose coefficient based on ICRP 107 data may differ from existing studies depending on the half-life and decay information of the nuclide. This suggests the need for a weighting factor based on the latest nuclide data. The results of this study can be used as a basis for the consideration of dose contributions for progeny radionuclides in various dose assessments.
        2.
        2023.05 구독 인증기관·개인회원 무료
        Natural radionuclides-containing substances (NORM) contain natural radionuclides and cause radiation exposure. In Korea, safety management measures were needed to deal with and dispose of radon mattresses containing monazite in relation to such NORM. However, there is no clear safety management system related to NORM waste in Korea. In order to manage this reasonably and systematically, it is necessary to investigate and analyze standards and management measures related to the treatment and disposal of NORM waste. Therefore, this study investigated and analyzed the exemption and clearance level of NORM waste regulations in international organizations and foreign countries. IAEA GSR Part 3, 2013/59/Euratom, ANSI/HPS N13.53, CRCPD SSRCR Part N, and ARPANSA Publications 15 safety management regulations were analyzed to investigate safety management standards for NORM waste. The exemption and clearance level in international organizations and foreign countries were compared and analyzed based on radioactive concentration and dose. In addition, the management measures proposed for each literature were also investigated. As a result of the analysis, IAEA GSR Part 3 applied 1 mSv as a regulatory exemption level, 1 Bq/g for uranium and thorium series as a clearance level, and 10 Bq/g for K-40 nuclides. The IAEA recommends a differential approach to the potential and scale of exposure. The EU applied 1 Bq/g to uranium and thorium families and 10 Bq/g to K-40 nuclides for both regulatory exemption and clearance levels. The EU recommended that it be managed in proportion to the scale and likelihood of exposure as a result of the action. It is analyzed that this is similar to the IAEA’s management plan. In the United States, there was no single federal government radioactive concentration and dose for NORM management. The management plan differed in management status and level from state to state, and K-40 was excluded from regulation unless it was intentionally enriched. In the case of Australia, the radioactive concentration of uranium and thorium was 1 Bq/g as a standard for regulatory exemption and 1 mSv as a dose. As a management plan, it was suggested to dispose of waste by means of accumulation, dilution/dispersion, and reclamation. It was also suggested that the scale of exposure, like international organizations, take into account the possibility. The results of this study are believed to be used as basic data for presenting domestic NORM waste treatment and disposal methods in the future.
        3.
        2022.10 구독 인증기관·개인회원 무료
        Currently, low and intermediate-level radioactive wastes and spent nuclear fuels are continuously generated in Korea. For the disposal of the radioactive wastes, the transport demand is expected to increase. Prior to transportation, it is necessary to evaluate the radiation risk of transportation to confirm that is not high. In Korea, there is no transportation risk assessment code that reflects domestic characteristics. Therefore, foreign assessment codes are used. In this study, before developing the overland transportation risk assessment code that reflects domestic characteristics, we analyzed the radiation risk assessment methodology in transportation accident codes developed in other countries. RADTRAN and RISKIND codes were selected as representative overland transportation risk assessment codes. For the two codes we analyzed accident scenarios, exposure pathways, and atmospheric diffusion. In RADTRAN, the user classifies accident severity for possible accident scenarios, and the user inputs the probability for each accident severity. On the other hand, in the case of RISKIND, the accident scenarios are classified and the probabilities are determined according to the NRC modal study (LLNL, 1987) in consideration of the cask impact velocity, cask impact angle, and fire temperature. In the case of RISKIND, the accident scenarios are applied only to transportation of spent nuclear fuel, and cannot be defined for low and intermediate-level radioactive waste. However, in the case of RADTRAN, since the severity and probability of accidents are defined by user, it can be applied to low and intermediate-level radioactive wastes. As the exposure pathways considered in transportation accident, both RADTRAN and RISKIND consider external exposure (cloudshine and groundshine), and internal exposure (inhalation, resuspension inhalation and ingestion). In the case of RADTRAN, additionally, external exposure due to loss of shielding (LOS) is considered. Atmospheric diffusion calculation is essential to determine the extent to which radioactive materials are diffused. In both RADTRAN and RISKIND, atmospheric diffusion calculations are based on Gaussian diffusion model. Users must input Pasquill stability class, release height, heat release, wind speed, temperature and mixing height, etc. Additionally, RADTRAN can input weather information relatively simply by inputting only the Pasquill stability class fraction and selecting the US average weather option. This study results will be used as a basis for developing radioactive waste overland transportation risk assessment code that reflects domestic characteristics.
        4.
        2022.10 구독 인증기관·개인회원 무료
        Cement is widely used as representative industrial material. In Korea, about 50 million tons of cement are consumed every year. In the manufacture of cement, raw materials containing NORM such as fly ash and bauxite are used. Therefore, the workers can be subjected to radiation exposure. The major exposure pathway in NORM industries is internal exposure due to inhalation of aerosol. Internal radiation dose due to aerosol inhalation varies depending on physicochemical properties of the aerosol. Therefore, the objective of this study was to investigate aerosol properties influencing inhalation dose in cement industries. In this study, aerosol properties were measured for two cement manufacturers. A particulate size distribution and concentration at various processing areas in cement manufacturing industries in Korea were analyzed using a cascade impactor. The mass density of raw materials and byproducts were measured using pycnometer. Shape of particulates was analyzed using SEM. The radioactivity concentration of Ra-226, Ra-228 for U/Th decay series was measured using HPGe. Particulate concentration by size was distributed log-normally with maximum at particle size about 7.2 μm in manufacturer A and 5.2 μm in manufacturer B. The mass density of fly ash and cement were 2.3±0.06, 3.2±0.02 g/cm3 respectively in manufacturer A. In manufacturer B, the mass density of bauxite and cement were 3.4±0.02, 2.9±0.01 g/cm3 respectively. The shape of particulates appeared as spherical shape in manufacturer A and B regardless of sampling area. Thus, a shape factor of unity could be assumed. The radioactivity concentrations of Ra-226, Ra-228 were 82±9, 82±8 Bq/kg for fly ash, and 25±4, 23±3 Bq/kg for cement in manufacturer A. In manufacturer B, the radioactivity concentrations of Ra-226, Ra-228 were 344±34, 391±32 Bq/kg for bauxite, and 122±13, 145±12 Bq/kg for cement. The radioactivity concentrations of Ra-226, Ra-228 in cement were less than raw materials such as fly ash and bauxite. It is because the dilution of the radioactivity concentration occurred during mixing with other raw materials in cement production process. This study results will be used as database for accurate dose assessment due to airborne particulate inhalation by workers in cement industries.
        5.
        2021.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We study galaxies undergoing ram pressure stripping in the Virgo cluster to examine whether we can identify any discernible trend in their star formation activity. We fi rst use 48 galaxies undergoing different stages of stripping based on Hi morphology, Hi de ficiency, and relative extent to the stellar disk, from the VIVA survey. We then employ a new scheme for galaxy classi fication which combines Hi mass fractions and locations in projected phase space, resulting in a new sample of 365 galaxies. We utilize a variety of star formation tracers, which include g - r, WISE [3.4]-[12] colors, and starburstiness that are de fined by stellar mass and star formation rates to compare the star formation activity of galaxies at different stripping stages. We find no clear evidence for enhancement in the integrated star formation activity of galaxies undergoing early to active stripping. We are instead able to capture the overall quenching of star formation activity with increasing degree of ram pressure stripping, in agreement with previous studies. Our results suggest that if there is any ram pressure stripping induced enhancement, it is at best locally modest, and galaxies undergoing enhancement make up a small fraction of the total sample. Our results also indicate that it is possible to trace galaxies at different stages of stripping with the combination of Hi gas content and location in projected phase space, which can be extended to other galaxy clusters that lack high-resolution Hi imaging.
        5,400원
        7.
        2018.10 구독 인증기관·개인회원 무료
        벼메뚜기는 분류학적으로 메뚜기목(Orthoptera), 메뚜기과(Acrididae)에 속하는 곤충으로 작물에 피해를 주는 해충으로 인식하고 있지만 예로부터 단백질 보충을 위하여 채집하여 튀기거나 볶음요리 로 이용해 왔다. 벼메뚜기는 갈색거저리, 쌍별귀뚜라미 등과 함께 식품공전에 등록되어 있으나 1년 1세대로 가을철에 채집하여 이용하는 실정으로 공급확대에 한계가 있다. 최근 우리나라에서 벼메뚜기를 사육하고자 하는 농가와 다양한 용도로 가공을 통해 이용하려는 수요가 점차 증가하고 있으나 연중사육기술이 개발되지 않아 대량사육하는 농가가 거의 없는 실정이다. 이에 벼메뚜기의 연중대량사육기술 뿐만 아니라 인공사료 및 자동화 사육시설 개발에 따른 생산비 절감 기술 개발이 필요한 실정이다. 벼메뚜기의 먹이로는 여름작물로 옥수수, 수단그래스, 겨울작물로 밀, 보리 등의 볏과작물이 있으며 많은 양의 생엽과 발육에 적합한 작물의 선발 및 볏과작물의 통곡실 가루를 이용한 인공사료의 개발로 먹이공급 부족 시 15~20일 급여 가능하며, 벼메뚜기 사육시설로 단독형, 연결형, 절충형 등의 사육시설을 개발하여 연결형 사육시설의 수확량과 생존율이 가장 높았으며, 예취 급이 노동력이 단독형의 16% 소요되었다.
        8.
        2016.10 구독 인증기관·개인회원 무료
        This studies was conducted to compare functional diversity of terrestrial arthropods in commercial apple orchards under conventional and organic practices. We collected terrestiral arthropods using pitfall traps in four conventional and seven organic apple orchards from April to October, 2012-2014. Sampled arthropods were identified at the species level and then classified three functional groups (detritivores, herbivores and beneficial arthropods included pollinators, parasitoids and predators). Biodiversity was analyzed with species richness, abundance and shannon index for each group and compared between conventional and organic orchards. In results, species richness of detritivores and benefical arthropods were higher in organic orchards than in conventional orchards (detritivores: t=-2.68, df=9, P=0.03; beneficial arthropods: t=-3.98, df=9, P=0.003). Organic orchards showed significant difference at abundance of beneficial arthropods (t=-3.33, df=9, P=0.008) and higher shannon index at detritivores (t=-2.36, df=9, P=0.04) than conventional orchards. However, all biodiversity indices of herbivores were not significantly different between conventional and organic orchards at 95% confidence level.
        9.
        2015.04 구독 인증기관·개인회원 무료
        This studies was conducted to define community structure and diversity of epigeal spiders in apple orchards under different farming practices (organic and conventional). In 11 commercial apple orchards, epigeal spider community structure was investigated during 2012-2014 (3 orchards, 2012; 3 orchards, 2013, 5 orchards, 2014). Epigeal spiders were collected by pitfall traps from April to October, 2012 in Danyang-gun, Chungcheongbuk-do; 2013 in Muju-gun, Jeollabuk-do; 2014 in Cheongsong-gun and Uiseong-gun, Gyeongsangbuk-do, Korea. Sampled spiders were identified to the species level. Biodiversity was analyzed with species richness (total numbers of spider species), abundance (total numbers of individuals) and Shannon-Wiener diversity index (H΄) for each site and compared between organic and conventional orchards. In all regions, abundance of the spider communities were relatively higher in organic orchards than in conventional orchards. But, no significant difference in species richness and specie diversity (H΄) between organic and conventional orchards. Lycosidae was the most dominant family in all orchards regardless farming practices. However, Linyphiidae dominated in organic orchards only. The most dominant species were Pardosa laura (Lycosidae), Erigone koshiensis (Linyphiidae) in organic, Piratula procurvus (Lycosidae) in conventional orchards.
        10.
        2014.04 구독 인증기관·개인회원 무료
        This study was conducted to investigate the community structure and species distribution of ground beetle assemblages in western part of Yeongwol-gun, Korea. Ground beetles were collected by pitfall traps from 9 study sites during July to October in 2013. A total of 30 species were identified from 4,439 collected ground beetles. Two dominant species, Synuchus nitidus (1,916 individuals) and Synuchus cycloderus (1,900 individuals) were occupied 85.8% of total. Interestingly, Pterostichus orientalis orientalis and Synuchus melantho were only collected in relative high altitude above 350 m, such as Beopheung-ri, Unhak-ri, and Yongseok-ri. Large-sized beetles, such as Damaster, Leptocarabus, and Carabus species, were generally more collected from Suju-myeon (Beopheung-ri and Unhak-ri) and Jucheon-myeon (Docheon-ri and Yongseok-ri) as well-conserved area, but not occurred in Yeongwol-eup and Hanbando-myeon, which forests may have lower habitat quality for these species. These differences also lead to increasing of dissimilarity among study sites, which were diverged into 3 groups at 53.0% of similarity. In particular, species composition of Samok-ri was significantly different at 8.2% of similarity because of difference in habitat characteristics as river side. This study has an important value to provide the fundamental information of inventory and monitoring in Yeongwol-gun. For detail mapping of species distribution in Yeongwol-gun, however, further studies are necessary, especially eastern parts of Yeongwol-gun.
        11.
        2014.04 구독 인증기관·개인회원 무료
        Epigeic spiders (Araneae) were surveyed in apple orchards under different farming practices (organic and conventional) in Muju-gun, Jeollabuk-do, Korea. The study was conducted from April to October in 2013 with 2 weeks interval using pitfall traps. Collected spiders were identified as 20 species of 6 families from 819 individuals in organic orchardⅠ, 19 species of 10 families from 759 individuals in orchardⅡ and 16 species of 8 families from 209 individuals in conventional orchard for from 1,787 captured spiders. Biodiversity was analyzed with species richness, abundance and Shannon diversity index (H΄). Species richness was statistically higher in organic orchard than in conventional orchard. Organic orchardⅡ comprised the greatest abundance followed by organic orchard and conventional. But species diversity was the highest in organic orchardⅡ, intermediate in conventional orchard and the lowest in orchardⅠ. Lycosidae was the most dominant family in all orchards regardless farming practices. However, Linyphiidae dominated in organic orchards only. The most dominant species were Erigone koshiensis (Linyphiidae) in organicⅠ, Pardosa laura (Lycosidae) in organicⅡ and Arctosa pungcheunensis (Lycosidae) in conventional orchard.
        12.
        2014.04 구독 인증기관·개인회원 무료
        Selecting surrogated species is the first step for environmental risk assessment of GM crop on non-target arthropods. To select surrogated species considering the domestic environment, we surveyed the arthropod fauna in five main localities (Changnyeong-gun in Gyeongsangnam-do, Goesan-gun in Chungcheongbuk-do, Gokseong-gun in Jeollanam-do, Hongcheon-gun in Gangwon-do and Hwaseong-si in Gyeonggi-do) in which maize was cultivated with large scale. Maize is one of the main imported GM crop in Korea. Arthropods were surveyed with yellow sticky traps and pitfall traps from May to August with a week interval considering the crop growing season in 2012 and 2013. A total of 135 species of 51 families in 13 orders were identified from the 17,470 arthropods. Six orders (Coleoptera, Araneae, Hemiptera, Diptera, Hymenoptera and Lepidoptera) were dominant in species richness and three orders (Collembola, Thysanoptera and Diptera) in abundance, representing 84% and 86% of the total, respectively. In the composition of fuctional guilds, herbivore group was the most dominant followed by predator group occupying 40% and 37% of the total abundance.
        13.
        2013.04 구독 인증기관·개인회원 무료
        In apple orchards under different farming practices (organic and conventional), arthropod community structure was investigated. Arthropods were collected with pitfall traps, band traps, yellow sticky traps and pheromone traps from May to December, 2012 in Danyang-gun, Chungcheongbuk-do, Korea. Biodiversity was analyzed with species richness and Shannon diversity index (H΄). Sampled arthropods were identified 37 families in 14 orders from 21,618 individuals in organic orchard-1 and 33 families in 10 orders from 11,318 individuals in organic orchard-2 and 35 families in 13 orders from 27,711 individuals in conventional orchard. Species richness was relatively highest in organic orchard-1, intermediate in conventional orchard and lowest in organic orchard-2. In ecologically functional group, abundance of pests was higher in conventional orchard than in organic orchards due to the high occurrence of Phyllonorycte ringoniella (Gracillariidae) and Lyonetia prunifoliella (Lyonetiidae). Organic orchards showed higher abundance, species richness and species diversity of epigeic predators and those of parasitoids above ground than conventional orchard. Abundance of detritivores, mainly collembola, were higher in organic orchard than in conventional orchard.
        14.
        2016.05 서비스 종료(열람 제한)
        Background : Clematis trichotoma is a deciduous climber belonging to the family Ranunculaceae. This study was carried out to survey the effect of shading levels on growth characteristics in Clematis trichotoma seedling. Methods and Results : Seeds were collected from plants growing in the Mt. Kariwang Jeongseon, Gangwon-do in October 2013, and they were sown to 96 cell plug tray filled with Peatmoss (TKS-2) soil at March, 2015. The experiment was performed with four different shading levels (0, 30, 60, 90%) at July, 2015. According to the experiment, plant height was the highest under 90% of shading. It was found that fresh weight and dry weight of clematis trichotoma were the highest under 90% of shading. The leaf number was the highest under 30% of shading. The leaf number decreased as the shading level increased. Root number and length were the highest under 90% of shading. Conclusion : According to the results, Clematis trichotoma seedling showed the highest growth under 90% shading.
        15.
        2016.05 서비스 종료(열람 제한)
        Background : Scrophularia koraiensis is a herbaceous perennials belonging to the family Scrophulariaceae. This study was carried out to survey the effect of soil types on growth characteristics in Scrophularia koraiensis seedling. Methods and Results : Seeds were collected from plants growing in the Mt. Kariwang Jeongseon, Gangwon-do in September 2014, and they were sown to 128 cell plug tray filled with Peatmoss (TKS-2) soil at March, 2015. The experiment was performed with four different soil types (Peatmoss, Peatmoss + Perlite, Peatmoss + Granite soil, Commercial soil). According to the experiment, stem diameter was the highest under commercial soil. The leaf width and length were the highest under commercial soil. Main root diameter and lengh were the highest under commercial soil. Conclusion : According to the results, Scrophularia koraiensis seedling showed the highest growth in commercial soil.
        16.
        2016.05 서비스 종료(열람 제한)
        Background : Scrophularia koraiensis is a herbaceous perennials belonging to the family Scrophulariaceae. This study was carried out to survey the effect of LED on root develop characteristics in Scrophularia koraiensis seedling. Methods and Results : Seeds were collected from plants growing in the Mt. Kariwang Jeongseon, Gangwon-do in September 2014, and they were sown to 128 cell plug tray filled with Peatmoss (TKS-2) soil at March, 2015. The experiment was performed with three different LED (Blue, Red, Blue + Red) at July, 2015. Morphological characteristics of root (total root length, root projet area, root surface area, root diameter and root volume) were analyzed with WinRHIZO software. Seedling root growth of scrophularia koraiensis was surveyed to be the highest at the Blue + Red LED in all measuring. Total root length was measured high in the order of Blue + Red, Red, Blue LED. Conclusion : According to the results, Scrophularia koraiensis seedling showed the highest root growth in Blue + Red LED.