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        검색결과 562

        42.
        2022.10 구독 인증기관·개인회원 무료
        This study was performed to assess the cosmic-ray effect caused by altitude in the aerial gammaray measurement. For the gamma-ray measurement experiment by altitude, the aerial survey system composed of four 4×4×16 inches large volume NaI (Tl) detectors was used. The aerial survey system was installed in a rotor-craft to stably keep its flight altitude and position. In addition, in order to avoid to time-dependent shielding effects with the amount of fuel, a rotor-craft of which the fuel tank is not located beneath the cabin floor was selected. In this study, the ROI (Region Of Interest) was set to the 3~6 MeV range to assess the cosmic-ray contribution to the gamma-ray spectrum that could ignore the contribution of the dominant natural radionuclides. The gamma-ray spectra measured inside and outside of the rotor-craft on the ground were compared to evaluate the shielding effects of the aircraft body. As a result, the count rate of the 40K photo peak was decreased by about 10% when measuring the inside compared to the outside. On the other hand, the total count rate of the 3~6 MeV region was decreased by about 0.7% under the same condition. Therefore, the aircraft body effect was insignificant in 3~6 MeV region considering the relative uncertainty of 0.04~0.78% (1σ). In addition, the count rate in the 3~6 MeV range according to altitude was evaluated to assess the cosmic-ray effect. In order to evaluate the change in the ROI count rate according to the altitude, the gamma-ray spectrum was measured in the range of 300~2,000 m above the sea to avoid the effect of terrestrial radiation. As a result, the relationship between altitude and count rate in the 3~6 MeV range showed a high correlation with the R2 value of 0.99, when the approximate equation was derived in the form of a quadratic polynomial. Also, the count rate of 3~6 MeV at 50~500 m above the ground was estimated using the correlation equation, and this value was compared with the measured count rate. As a result of comparing the average value of estimated count rate and measured count rate, the relative difference is less than 2%. Considering the relative uncertainty of 0.78~4.11% (1σ), it was possible to evaluate the count rate of the 3~6 MeV region relatively accurately. The results of this study could be used for further study on background dose corrections in aerial survey.
        46.
        2022.10 구독 인증기관·개인회원 무료
        For safe management of spent nuclear fuels, they should be delivered to repository or waste disposal site. As the amount of spent nuclear fuel transportation is expected to increase in the future due to the provision of an intermediate storage facility, the necessity to secure transportation cask is emerging. In order to secure the spent nuclear fuel transportation cask, it is necessary to analyze the regulatory processes for domestic and foreign spent nuclear fuel transportation cask. In this study, the regulatory processes for domestic and foreign spent nuclear fuel transportation cask was analyzed. In this study, the IAEA, US, and Korea spent nuclear fuel transportation cask regulatory processes were analyzed. The domestic and foreign spent nuclear fuel transportation cask regulatory processes consist of design phase, manufacturing phase, and operation phase. In the design stage, the transport requirements are designed in accordance with the safety requirements of international organizations and countries. The application to be submitted when applying for approval should include a safety analysis report, evidence proving compliance with safety requirements et al. In the manufacturing stage, it is a stage to check whether the safety requirements are satisfied before the first use after manufacturing the transportation cask. Inspections include welding inspection, leakage inspection, shielding inspection, and thermal inspection. In the operation stage, it is a stage of periodically performing inspections for continuous maintenance of the package when the transportation cask is used. The inspection items to be performed are similar to the manufacturing stage and typically include performance inspection of components and leakage inspection. In this study, domestic and foreign spent nuclear fuel transportation cask regulatory processes were analyzed. It was found that the domestic and foreign spent nuclear fuel transportation cask regulatory processes consist of the design phase, the manufacturing phase, and the operation phase. The results of this study can be used as basic data for policy decision-making for the spent nuclear fuel cask.
        47.
        2022.10 구독 인증기관·개인회원 무료
        One of the promising candidates for heat transfer fluid is molten chloride salts. They have been studied in various fields such as the electrolyte of pyroprocessing, the molten salt reactor coolant, and the energy storage system media. Main considerations for utilizing molten chloride salts are the compatibility of salts with structural materials. The corrosion behavior of structural materials in molten chloride salts must be understood to identify suitable materials against the corrosive environment. In this study, the corrosion behavior of a candidate structural material, Hastelloy N, in molten LiCl- KCl salt at 500°C were investigated by the electrochemical impedance spectroscopy (EIS) method. The sheet type of Hastelloy N was utilized as the working electrode in LiCl-KCl to measure the EIS data for 100 hours with 5 hours of time intervals. The EIS data were measured in the frequency range from 104 Hz to 10-2 Hz with the AC signal (amplitude = 20 mV) at open circuit potential. The capacitance semicircle observed in Nyquist plots for all periods indicates that charge-transfer controlled reactions occur. As the immersion time progresses, the radius of the semicircle in Nyquist plots and the impedance and phase angle in Bode plots decrease. These behaviors suggest a decreasing reaction resistance and the corrosion reactions are accelerated with the immersion time. The EIS data were fitted using the equivalent circuit to achieve quantitative results. Two capacitor-resistor components were considered due to the overlapped shape of two valleys in phase angle. The depressed shape of the semicircle in Nyquist plots led to the use of the constant phase element(Q) instead of the capacitor. Therefore, R(Q(R(QR))) circuit was selected to fit the EIS data. Fitting results show that the charge transfer resistance decreases dramatically within 1 day and then converges. The film resistance shows no clear trends, but the increase of the film admittance value indicates the decreased film thickness. Consequently, the film appears to exist like the oxide layer but it does not act as a protective layer. The real-time EIS data were measured in molten salt and provides the corrosion behavior over time. The corrosion mitigation strategy should consider that the corrosion of Hastelloy N accelerates over time and its intrinsic film cannot act as the protective layer. The next steps of this study are to evaluate other candidate structural materials and to demonstrate the presence of the film.
        51.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Digitization and automation technologies have rapidly maximized productivity and efficiency in all industries over the past few decades. Construction automation technology has either stagnated over the same period or has not kept pace with overall economic productivity. According to the research studies up to now, the output of concrete structures using coarse aggregates (8mm or more) is very limited due to the limitations of equipment and materials. In this study, information on the development process of 3DCP equipment that can print concrete structures with the printing width (100 mm or more) and printing thickness (30 mm or more) using a 3DCP material mixed with coarse aggregate (8 mm or more) is provided. To verify the performance of the developed 3DCP equipment, experimental data are provided on output variables, the number of layers, and the inter-layer printing time interval. The evaluation and verification data of various mechanical properties (compressive and splitting tensile strength) of printed materials using coarse aggregates are provided.
        4,300원
        53.
        2022.05 구독 인증기관·개인회원 무료
        In Korea, research on the introduction of dry storage facility is being conducted as an alternative to saturation of temporary storage facilities for spent nuclear fuel. The introduction of dry storage facilities requires a radiological impact assessment on the workers of the facility, and for this, an appropriate exposure scenario must be derived through work procedure analysis. In this study, the procedure for storing spent nuclear fuel in dry storage facilities was analyzed based on the case of evaluating the radiological impact of workers in dry storage facilities abroad. We investigated cases of radiological impact assessment on workers at on-site dry storage facilities by PNNL, Dominion, and P. F. Weck. PNNL and Dominion analyzed the storage work procedure of the VSC (Vertical Storage Cask) method using CASTOR V/21, TN-32, respectively, and conducted a radiological impact assessment. P. F. Weck analyzed the storage work procedure of various spent nuclear fuel casks for VSC and HSM (Horizontal Storage Module), conducted a radiological impact assessment. As a result of comparing the procedure for storing spent nuclear fuel by case, it was found that the storage procedure was determined by the storage method and the cask type. In the case of VSC method, canister-type casks and basket-type casks are used, and the storage procedure are partially different according to each. Canister-type cask requires repackaging from transfer overpack to storage overpack, but basket-type cask doesn’t require that procedure. In the case of the HSM method, only the canister type cask was found to be used. However, the storage procedure was different depending on the type of HSM system. Depending on the type of HSM system, the necessity of cask for on-site transport was different. In this study, we investigated and analyzed the work procedure according to the storage method of dry storage facilities abroad. It was found that the dry storage procedure of spent nuclear fuel different according to the storage method and type of cask. The results of this study can be used as basic when deriving the exposure scenario for spent nuclear fuel dry storage workers suitable for the domestic situation.
        54.
        2022.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Non-destructive estimation of leaf area is a more efficient and convenient method than leaf excision. Thus, several models predicting leaf area have been developed for various horticultural crops. However, there are limited studies on estimating the leaf area of strawberry plants. In this study, we predicted the leaf areas via nonlinear regression analysis using the leaf lengths and widths of three-compound leaves in five domestic strawberry cultivars (‘Arihyang’, ‘Jukhyang’, ‘Keumsil’, ‘Maehyang’, and ‘Seollhyang’). The coefficient of determination (R2) between the actual and estimated leaf areas varied from 0.923 to 0.973. The R2 value varied for each cultivar; thus, leaf area estimation models must be developed for each cultivar. The leaf areas of the three cultivars ‘Jukhyang’, ‘Seolhyang’, and ‘Maehyang’ could be non-destructively predicted using the model developed in this study, as they had R2 values over 0.96. The cultivars ‘Arihyang’ and ‘Geumsil’ had slightly low R2 values, 0.938 and 0.923, respectively. The leaf area estimation model for each cultivar was coded in Python and is provided in this manuscript. The estimation models developed in this study could be used extensively in other strawberry-related studies.
        4,000원
        58.
        2022.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted at the National Institute of Animal Science (NIAS) from 2010 to 2017 to develop a late-maturing variety with high productivity for cultivation in the southern region of South Korea. The new variety of Italian ryegrass, ‘IR901’, was a late-maturing variety, and its heading date was 22 May, 17 days later than that of the control variety ‘Kowinearly’. ‘IR901’ had a flag leaf width of 11.2 mm, flag leaf length of 31.8 cm, and plant length of 103 cm on its heading date. The combined average dry matter yield of ‘IR901’ in all three adaptability evaluation regions (Cheonan, Pyeongchang and Haenam) was 7,747 kg/ha, which was similar to that of the ‘Kowinearly’ variety (7,734 kg/ ha). However, the average dry matter yield over three years in Cheonan and Pyeongchang was 82% and 96%, respectively, compared to that of the control, which was most likely because of the poor cold tolerance of ‘IR901’. By contrast, in Haenam, in the southern region, the average dry matter yield of ‘IR901’ was 19% higher than that of the ‘Kowinearly’ variety. The proportions of crude protein (CP), total digestible nutrients (TDN), acid detergent fiber (ADF), and neutral detergent fiber (NDF) in ‘IR901’ were 8.6%, 59.7%, 36.9%, and 54.8%, respectively; the proportions were 0.2% lower, the same, the same, and 2.5% lower than those in the ‘Kowinearly’ variety. The determined in vitro dry matter digestibility (IVDMD) of ‘IR901’ was 72.2% higher than that of ‘Kowinearly’ (67.2). In general, of the two varieties, the forage quality of ‘IR901’ was marginally superior to that of ‘Kowinearly’.
        4,000원
        59.
        2021.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Colorectal cancer causes the most cancer-associated death worldwide, having a high cancer incidence. Pectin is a complex polysaccharide present in various fruits, emerging as an anti-carcinogenic candidate. Although pectin has a suppressive capacity for colon carcinogenesis, the effect of reactive oxygen species (ROS) generation and colonic aberrant foci formation in the colon carcinogenesis mouse model remains unclear. Therefore, this study investigates the regulatory effect of pectin supplementation on colon carcinogenesis induced by azoxymethane (AOM) and dextran sodium sulfate (DSS) in mice. In an animal experiment, thirty male institute for cancer research (ICR) mice were divided into two experimental groups; AOM/DSS (control group) and AOM/DSS + pectin (5% in drinking water). Furthermore, the number of aberrant crypt foci (ACF) and aberrant crypt (AC) on colonic mucosa were counted, and thiobarbituric acid-reactive substances (TBARS) assay was performed to estimate lipid peroxidation in feces. Pectin treatment significantly decreased the number of ACF and AC per colon compared with the control. Additionally, fecal TBARS level in the pectin group was significantly lower than those in the control group. Conclusively, these findings indicate that pectin-inhibited hyperplastic alteration and oxidative stress suppress colitis-associated colon carcinogenesis.
        4,000원
        60.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Trading card game은 사용자들이 카드를 수집하고 교환하면서 게임을 진행한다. 사용자는 카드별로 존재하 는 특수 능력과 필요 비용 등을 고려하여 카드를 수집한다. 한정판 카드는 카드에 희소가치를 부여하여 사용 자들의 수집욕을 자극하여 구매를 유도할 수 있다. 기존 Trading card game인 Slay the Spire나 Hearths Sto ne는 초기 덱 빌딩할 때, 사용자의 능력보다는 운이 영향을 끼친다. 카드 구성을 변경하는 것이 쉽지 않으므 로, 초기 덱 빌딩 결과가 게임의 승패에 결정적인 영향을 주기도 한다. 반면에, Legends of Runeterra는 게임 의 규칙이 너무 복잡해서, 초보자들이 게임을 어렵다고 느낀다. 이러한 점을 고려하여, 제안하는 게임 매직 파이트는 다음과 같은 특징이 있다. 초보자들도 쉽게 게임을 플레이할 수 있도록, 제안하는 게임은 덱 빌딩 방법을 단순하게 구성한다. 사용자들이 다양한 전략을 시도해 볼 수 있도록, 매 판마다 덱 구성을 변경할 수 있다. 실험결과 덱 빌딩시 카드의 종류를 일부 제한하면 상대적으로 카드 구성이 단순해서, 사용자가 카드의 효과와 이미지를 쉽기 이해하는 경향을 보인다. 반면에, 모든 종류의 카드를 대상으로 덱 빌딩을 하면, 사용 할 수 있는 카드의 수가 상대적으로 많으므로, 사용자가 다양한 전략을 시도해 볼 수 있어서 더 재미있었다 고 응답하였다.
        4,000원
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