검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 57

        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.
        4.
        2023.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국내 현대정원의 조성 디자인 경향성을 확인하고자 우수 경 관 정원 80개소 대상으로 적용 양식 및 정원 식물을 조사하였 다. 조사 대상 80개소 정원 중 53.7%는 서울 및 수도권, 46.3%는 그 외 지역에 소재하고 있다. 또한, 관리 유형에 따 라 공동 정원, 상업시설 정원, 개인 정원으로 구분 되었으며, 각 62.5%, 21.3%, 16.2%로 나타났다. 19~20세기 해외 정원 사조에 따라 조성 양식은 12유형(정형식, 비정형식, 정형 및 비정형 복합식, 건축식, 자연, 신풍경, 뉴저먼 스타일, 모더니 즘, 프레리 스타일, 뉴웨이브 스타일, 낭만주의, 예술작품 정 원)으로 분류되었다. 우리나라 현대 정원은 단일 및 복합 양식 활용이 각 55.0%와 45.0%로 유사하였다. 주로 정형 및 비정 형 복합식 정원이 활용되는 반면, 정형 및 비정형 복합식 정원 대비 낭만주의, 모더니즘, 프레리 및 뉴웨이브 스타일 이용 빈 도는 0.02~0.06배 수준이었다. 조성 양식 활용에 따라 이용 되는 식물 소재 유형에는 큰 차이가 없었으나, 특정 디자인에 서 식재 빈도가 높은 분류군을 확인했다.
        4,600원
        5.
        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.
        6.
        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.
        7.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 수확 후 저장 기간에 따른 절화 장미의 수명 변화를 알아보았다. 절화장미 ‘Antique Curl’을 수확 직후 4℃ 암조건의 저장고에서 0일(무처리), 1일, 3일, 5일, 7일간 보존 용액 처리 후 습식 저장하였다. 저장이 끝난 절화는 24℃ 실 내 광환경으로 옮겨 절화 보존제 유무 조건에서 절화수명을 조사하였다. 그 결과, 절화수명은 저장기간 3일차까지는 20일 전후로 높았으나, 5일차 이후 유의적으로 감소했다. 절화 보 존제는 절화수명 연장에 효과적이지는 않았으나 절화의 꽃목 굽음 현상을 완화시켰다. 엽록소 형광(Fv/Fm)은 저장 기간과 관계없이 0.78~0.82 수준으로 나타났으며 저장기간에 의한 광 생리 기능저하는 확인되지 않았다. 결과적으로 절화장미 ‘Antique Curl’의 상업적 저장 기한은 최대 5일로 확인되었다.
        4,000원
        8.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        계절에 따른 정원의 경관 변화 특성을 알아보고자, 우수 정 원 4개소를 대상으로 계절별 식재 특성과 색채 변화를 분석하 였다. 대상 정원에서 계절별로 조사된 식재 종수 합은 346분 류군이었고, 교목:관목:초본의 식재 백분율(%)은 8:21:71로 나 타났다. 초본은 봄을 기준으로 여름과 가을에 각각 6%와 15% 증가하였다. 관목은 봄에서 가을까지 계절 변화에 따라 64-100% 증가하였다. 계절에 따라 정원의 포인트 식물이 달라 졌으나, 꽃이 만발하는 초본과 관목으로 나타났다. 색채 분석 결과, 정원의 주조색은 식물 생육이 왕성한 봄과 여름에는 녹 색에서 짙은 녹색으로 나타났고, 가을에는 갈색으로 확인되었 다. 강조색은 계절에 따라 분명하게 달라졌으며, 주로 계절별 특징적인 화색이나 잎무늬로 결정되었다.
        4,000원
        12.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        우리나라 정원의 식물 이용 현황을 알아보고자 전국 36개 정원을 대상으로 정원식물을 조사하였다. 정원은 6가지 유형 으로 구분하였다. 그 결과, 36개소 정원에는 정원식물 712종 류가 식재되고 있었다. 교목, 관목, 초본의 비중은 평균 1:2:7 이었다. 개별 정원(10×10㎡)에서 교목은 평균 2.5종으로 12.6%, 관목은 4.1종 20.7%, 초본은 13.2종 66.7%를 차지했다. 식재 빈도 상위 5%에 40여 종이 포함되었으며, 맥문동, 일본조팝나 무, 수국, 회양목, 단풍나무, 옥잠화, 에키네시아, 산철쭉이 대 표적이었다. 양지형 정원에는 관목이 상대적으로 적고 초본이 많았으며 다른 유형보다 20~40% 이상 다양했다. 그늘형은 초 본보다 교목이 많았으며, 건조형 및 습지형과 마찬가지로 식 재 다양성이 20% 감소했다. 옥상정원의 도시형 정원은 초본 이 전체의 80~90%를 차지하고, 해안형 정원에는 목본과 초본 이 1:1로 목본 중심의 식재 특성을 보였다. 결과적으로 정원 유형에 따라 식재 다양성과 구성 비율이 명확한 차이를 나타 냈다.
        4,000원
        13.
        2022.03 구독 인증기관 무료, 개인회원 유료
        Humulus japonicus (HJ) is a widely used herbal medicine for pulmonary tuberculosis, hypertension, leprosy, and venomous wounds in Asia, particularly in China. Although HJ has certain physiological activities, such as longitudinal bone growth, antioxidation and alleviation of rheumatism, its anticancer activities, other than in colorectal and ovarian cancer, are yet to be studied. In this study, we investigated the anti-cancer activity and mechanism of methanol extracts of HJ (MeHJ) against human FaDu hypopharyngeal squamous carcinoma cells. MeHJ suppressed FaDu cell viability without affecting normal cells (L929), which was demonstrated using the MTT and Live & Dead assays. Furthermore, MeHJ effectively inhibited colony formation of FaDu cells, even at non-cytotoxic concentrations, and significantly induced apoptosis through the proteolytic cleavage of caspase-9, -3, -7, poly (ADP-ribose) polymerase and through the downregulation of BCL-2 and upregulation of BAX in FaDu cells, as determined by DAPI staining, flow cytometry, and western blot analyses. Collectively, these findings suggest that the inhibitory effects of MeHJ on the growth and colony formation of oral cancer cells may be mediated by caspase- and mitochondrial-dependent apoptotic pathways in human FaDu hypopharyngeal squamous carcinoma cells. Therefore, MeHJ has the potential to be used as a natural chemotherapeutic drug against human oral cancer.
        4,000원
        19.
        2021.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To increase the selection efficiency for new cultivars in cut roses during breeding programs, phenotypes of seedlings in two cross combinations, C1 (Rosa hybrida ‘Yellow King’ x ‘Aladin’) and C2 (R. hybrida ‘Evelien’ x ‘Sunny Isle’), were investigated. Although most seedlings showed classic-type flower shapes, some (0.4% - 0.7%) had tomato-shaped flowers, especially at the young plant stage (6 months old). The variation in petal color was high, and pink and pink-mixed flowers were dominant, accounting for 72% in C1 and 76% in C2 at the mature plant stage (13-month-old plants). However, the seedlings had changes in the expression of petal color at different growth stages. The number of petals at the young plant stage had a strong positive correlation with those at the mature plant stage in C1 (r = 0.84***) and C2 (r = 0.73***). Sizes of flowers and petals increased with the growth of the seedlings, and their traits at the young plant stage had positive correlations with those at the mature plant stage in both C1 (r = 0.32***) and C2 (r = 0.39***). Prickle expression on stems was mostly in level 5 at the young plant stage and then dispersed to various classes at the mature plant stage, which increased the variation and coefficient of variation. To select seedlings for new cultivars through breeding processes, breeders should consider the growth stage for targeted traits.
        4,000원
        1 2 3