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        검색결과 1,359

        81.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was designed to evaluate antihyperglycemic and antihyperlipidemic effects of ethanol extracts of Taraxacum mongolicum (T.m.) on streptozotocin (STZ)-induced diabetic rats. Sprague-Dawley rats were randomly assigned to five groups: normal (NC), STZ-control (DC), and three experimental groups. Diabetes was induced in Sprague-Dawley rats with a single intravenous injection [45 mg/kg body weight (b.w.)] of STZ. An ethanol extract of T.m. was orally given to diabetic rats for 14 days. Three experimental groups were additionally treated with T.m. extract at doses of 1 g/kg b.w./day for T.m.-1, 2 g/kg b.w./day for T.m.-2, and 3 g/kg b.w./day for T.m.-3. Oral administration of T.m.-2 significantly increased their body weights. T.m.-1 and T.m.-2 significantly decreased aspartate aminotransferase (AST) levels than DC. T.m.-1 and T.m.-2 group significantly decreased blood glucose levels. Total cholesterol, triglycerides, and free fatty acids were significantly decreased whereas high-density lipoprotein cholesterol was significantly increased in groups treated with T.m. extract than those in the DC group. These results support the fact that administration of T.m. extract can reduce hyperglycemia and hyperlipidemia risk in diabetic rats.
        4,000원
        82.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Labidocera pavo Giesbrecht, 1889 and L. sinilobata Shen and Lee, 1963, belonging to the detruncata group in the genus Labidocera were collected from the southwestern coastal waters of Korea, using a Norpac net (0.2 mm mesh size). Labidocera sinilobata, known to be endemic species in estuary of Chinese rivers, is the first record in Korean waters. In Chinese waters, this species has only been briefly documented and illustrated. In the study, their morphological characteristics were fully redescribed with careful examination of the fine epidermal structure using a SEM (Scanning Electron Microscope) in addition to their illustrations and compared with species of the detruncata species-group.
        4,000원
        83.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 SAP를 국화(Chrysanthemum morifolium) 분화 생산에 활용하고 SAP의 혼합 비율에 따른 물 사용량과 국화 의 생육을 비교하고자 수행하였다. SAP를 배지의 부피비인 0, 0.05, 0.1, 0.2%로 섞었으며 각각의 처리구는 토양수분함 량 0.50m3・m-3로 일정하게 유지시켰다. 국화의 성장은 초장, 초폭, 뿌리 길이, 개화소요일수를 조사하였다. SAP 0, 0.05, 0.1, 0.2% 처리구에 따르면 식물체의 초장, 초폭, 생체중은 처리구간에 유의한 차이가 없었다. 그러나 지하부 건물중에서 는 0.2% SAP 처리가 대조구보다 유의하게 높았다. 실험 기간 동안 SAP의 혼합 비율에 따라 사용되는 관수량에는 상당한 차이가 있었다. 관수량은 0, 0.05, 0.1, 0.2% SAP 처리에서 각각 43.5, 37.2, 30.1, 29.4L이었다. 결론적으로 동일한 토 양수분조건하에서 SAP의 양에 따른 국화의 생육에는 차이가 없었으나, SAP를 통해 토양의 보수력을 향상시켜 사용되는 물의 양을 크게 줄일 수 있었다.
        4,000원
        84.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The paint removal of fighter jets is just as important as the painting, because perfect paint removal ensures the quality of the exterior painting on the aircraft. However, the current conditions for paint removal work of the ROKAF’s are poor. It is identified that the painting process currently implemented by the ROKAF is not only exposed to harmful compounds such as harmful dust and hexavalent chromium, but also consumes a lot of water. Thus, the introduction of advanced facility is considered. This study compares the fighter jets painting removal process currently applied by the Korean Air Force with the improved laser coating removal process of the US Air Force, and conducts an incremental analysis to perform economic analysis for the introduction of advanced facility. Four scenarios were envisioned on the premise of an increase in the number of fighters in the future, incremental analysis shows that laser coating removal method is advantageous in all scenarios. In addition, it is recommended that paint removal cycle keeps the current 12-year and the outsourcing amount to civilian depot is reduced.
        4,500원
        94.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this experiment was to investigate the effect of drip irrigation volume on tomatoes (Solanum lycopersicum L.) grown in a greenhouse using perlite medium. Plants were treated by three different irrigation treatment I0, I25, and I50 (where irrigation volume of I25 and I50 was 25% and 50% higher than I0, having limited or no leaching). Growth characteristics of plants, yield and water use efficiency were measured. The result showed that plant height, leaf length and leaf width were lowest in the I0 treated plants. However, these parameters were not statistically significant differences between the plants that were grown in the I25 and I50 treatment. Soluble solids content, acidity and dry matter of 111th, 132nd, and 143rd days harvested tomato were higher in the plants irrigated with lowest volume (I0) than the higher volume (I25 or I50). In addition, water content was lower in the 111th and 132nd days of harvested tomatoes from the I0 treatment. The number of big-size tomatoes (>180 g) was significantly higher in the I25 irrigated plants. There was no significant difference in the total number of harvested fruits among the treatments. The average fruit weight and total yield of harvested tomatoes were lowest in the I0 treated plants. The water consumption of tomato was not significantly different amongst the treatments but water use efficiency was lowest in the I0 treatment. Principal component analysis revealed that total soluble solid and acidity of tomato showed a positive correlation between each other. These results suggest that I25 was the optimum irrigation treatment for tomato based on its measured growth characteristics, yield and water use efficiency.
        4,200원
        95.
        2022.10 구독 인증기관·개인회원 무료
        Since radon was detected in mattresses of famous bed furniture brands in 2018, the nuclear safety and security commission (NSSC) announced the radiation safety management act in April 2021 to protect the public health and environment. This act stipulates the safety management of radiation that can be encountered in the natural environment such as the notification of radioactivity concentration of source materials, process by-products, the installation and operation of radioactive monitors. In this study, a model was established to predict radioactive exposure dose from radioactive materials such as radon and uranium detected in consumer products such as bed mattresses, pillows, shower, bracelets and masks in order to identify major radioactive substances that largely affect the exposure dose. A period of seven years from 2014 to 2020 was investigated for the source materials and exposure doses of consumer products containing naturally occurring radioactive materials (NORMs). We analyzed these using machine learning models such as classification and regression tree (CART), Random Forest and TreeNet. Index development and verification were performed to evaluate the predictive performance of the models. Overall, predictive performance was highest when Random Forest or TreeNet was used for each consumer product. Thoron had a great influence on the internal exposure dose of bedding, clothing and mats. Uranium had a great influence on the internal exposure dose of other consumer products except whetstones. When the number of data is very small or the missing value rate is high, it is difficult to expect accurate predictive performance even with machine learning techniques. If we significantly reduce the missing value rate of data or use the limit of detection value instead of missing values, we can build a model with more accurate predictive performance.
        96.
        2022.10 구독 인증기관·개인회원 무료
        Republic of Korea (ROK) is operating the Integrated Environmental Radiation Monitoring Network (IERNet) in preparation for a radioactive emergency based on Article 105 of the Nuclear Safety Act (Monitoring of Nationwide Radioactive Environment). 215 radiation monitoring posts are monitoring a wide area, but their location is fixed, so they can’t cover areas where the post is not equipped around the Nuclear Power Plants (NPPs). For this, a mobile radiation monitoring system was developed using a drone or vehicle. However, there are disadvantages: it is performed only at a specific cycle, and an additional workforce is required. In this study, a radiation monitoring system using public transportation was developed to solve the above problems. Considering the range of dose rates from environmental radiation to high radiation doses in accidents, the detector was designed by combining NaI (TI) (in the low-dose area) and GM detector (in the high-dose area). Field test was conducted by installed on a city bus operated by Yeonggwang-gun to confirm the performance of the radiation monitoring system. As a result of the field test, it was confirmed that data is transmitted from the module to the server program in both directions. Based on this study, it will be possible to improve the radiation monitoring capability near nuclear facilities.
        97.
        2022.10 구독 인증기관·개인회원 무료
        Waste containers for packaging, transportation and disposal of NPP (Nuclear Power Plant) decommissioning wastes are being developed. In this study, drop tests were conducted to prove the safety of containers for packaging of the wastes and to verify the reliability of the analysis results by comparing the test and analysis results. The drop height of the waste containers was considered to be 30 mm, which is the maximum lifting speed of a 50 tons crane in the waste treatment facility converted to the drop height. Drop orientation of the containers was considered for bottom-end on drop. The impact acceleration and strain data were obtained to verify the reliability of the analysis results. Before and after the drop tests, measurement of the dose rate and the radiographic testing for concrete wall, and measurement of the wall thickness of steel plate were conducted to evaluate the radiation shielding integrity. Also, measurement of bolt torque, and visual inspection were conducted to evaluate the loss or dispersion of radioactive contents. After the drop tests, the radiation dose rate on the container surface did not increase by more than 20%, and there was no crack in the concrete. In addition, the thickness of the steel plate did not change within the measurement error. Therefore, the radiation shielding integrity of the container was maintained. After the drop tests, the lid bolts were not damaged and there was no loss of pretension in the lid bolts. In addition, there was no loss or dispersion of the contents as a result of visual inspection. In order to prove the reliability of the drop analysis results, safety verifications were performed using the drop test results, and the appropriate conservatism for the analysis results and the validity of the analysis model were confirmed. Therefore, the structural integrity of the waste containers was maintained under the drop test conditions.
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