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        검색결과 102

        1.
        2023.05 구독 인증기관·개인회원 무료
        In Korea, many characteristic component facilities and technologies in general experimental areas for non-radiative materials are owned by industry-academia research. Still, no characteristic analysis test technology has been developed for large, intermediate-level decommissioning waste emitted by neutron irradiation. Since Korea plans to decommission nuclear power plants in 2027, securing analysis technology for intermediate-level decommissioning waste is essential. Accordingly, the Korea Research Institute of Decommissioning (KRID) plans to secure an infrastructure (hot cell) to analyze the characteristics of intermediate-level dismantled waste. Afterward, we intend to stably dispose of the waste generated while decommissioning the current Gori Unit 1/Wolseong Unit 1 using the intermediatelevel dedicated hot cell. It aims to secure high-dose/high-radiation decommissioning waste handling technology through intermediate-level hot cells for the first time in Korea, supports domestic nucleardecommissioning projects, and secure and validate procedures related to material characteristics and nuclide analysis of intermediate-level waste. Furthermore, research on intermediate-level radioactive materials is expected to be carried out in cooperation with schools and research institutes.
        4.
        2022.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This research investigated the effect of Si addition on the microstructure, mechanical properties, electric and thermal conductivity of as-extruded Al 6013 alloys. As the content of Si increased, the area fraction of the second phase increased. As the Si content increased, the average grain size decreased remarkably, from 182 (no Si addition) to 142 (1.5Si), 78 (3.0Si) and 77 μm (4.5Si) due to dynamic recrystallization by the dispersed second particles in the aluminum matrix during the hot extrusion. As the Si content increased, the yield strength and ultimate tensile strength increased. The maximum values of yield strength and ultimate tensile strength were 224 MPa and 103 MPa for the 6013-4.5Si alloy. As the amount of Si added increased, the electrical and thermal conductivity decreased. The electrical and thermal conductivity of the Al6013-4.5Si alloy were 44.0% IACS and 165.0 W/mK, respectively. The addition of Si to Al 6013 alloy had a significant effect on its thermal conductivity and mechanical properties.
        4,000원
        5.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Kale (Brassica oleracea var. acephala) is one of the most frequently consumed leafy vegetables globally, as it contains numerous nutrients; essential amino acids, phenolics, vitamins, and minerals, and is particularly rich in glucosinolates. However, the differences in the biosynthesis of glucosinolates and related gene expression among kale cultivars has been poorly reported. In this study, we investigated glucosinolates profile and content in three different kale cultivars, including green (‘Man-Choo’ and ‘Mat-Jjang’) and red kale (‘Red-Curled’) cultivars grown in a vertical farm, using transcriptomic and metabolomic analyses. The growth and development of the green kale cultivars were higher than those of the red kale cultivar at 6 weeks after cultivation. High-performance liquid chromatography (HPLC) analysis revealed five glucosinolates in the ‘Man-Choo’ cultivar, and four glucosinolates in the ‘Mat-Jjang’ and ‘Red-Curled’ cultivars. Glucobrassicin was the most predominant glucosinolate followed by gluconastrutiin in all the cultivars. In contrast, other glucosinolates were highly dependent to the genotypes. The highest total glucosinolates was found in the ‘Red-Curled’ cultivar, which followed by ‘Man-Choo’ and ‘Mat-Jjang’. Based on transcriptome analysis, eight genes were involved in glucosinolate biosynthesis. The overall results suggest that the glucosinolate content and accumulation patterns differ according to the kale cultivar and differential expression of glucosinolate biosynthetic genes.
        4,200원
        8.
        2021.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this paper, the effect of Ni (0, 0.5 and 1.0 wt%) additions on the microstructure, mechanical properties and electrical conductivity of cast and extruded Al-MM-Sb alloy is studied using field emission scanning electron microscopy, and a universal tensile testing machine. Molten aluminum alloy is maintained at 750 oC and then poured into a mold at 200 oC. Aluminum alloys are hot-extruded into a rod that is 12 mm in diameter with a reduction ratio of 39:1 at 550 oC. The addition of Ni results in the formation of Al11RE3, AlSb and Al3Ni intermetallic compounds; the area fraction of these intermetallic compounds increases with increasing Ni contents. As the amount of Ni increases, the average grain sizes of the extruded Al alloy decrease to 1359, 536, and 153 μm, and the high-angle grain boundary fractions increase to 8, 20, and 34 %. As the Ni content increases from 0 to 1.0 wt%, the electrical conductivity is not significantly different, with values from 57.4 to 57.1 % IACS.
        4,000원
        9.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study attempted to determine the characteristic features of postpartum dairy cows during their return to estrus. Moreover, it investigated the effects of abnormal ovarian cycles (AOC) on subsequent reproductive performance and the relationship between normal ovarian cycles (NOC) and the blood urea nitrogen (BUN) level postpartum. Incidentally, 56.3% of the Holstein cows and 66.7% of the Jersey cows had NOC, whereas the 43.7% and 33.3% of the Holstein and Jersey, respectively, had AOC. Within 100 days of calving, the cows with AOC had significantly lower rates of artificial insemination (AI) submission as well as pregnancy and a significantly longer interval to first AI, as compared to that in the cows with NOC. Additionally, the cows with NOC had a significantly higher first AI conception rate than that in the cows with AOC. In this study, of the 32 Holstein cows, 8 resumed their ovarian cycle within 20 days of calving, 10 resumed the cycle with 21-40 days of calving, 8 within 41-60 days of calving, while the remaining 6 did not resume their ovarian cycles until 60 days postpartum. Furthermore, the likelihood ratios of incidence of NOC are 0.93, 1.94, and 0.38, respectively, in the groups with BUN levels < 15, 15-19.9, and ≥ 20 mg/ dl. In conclusion, AOC postpartum adversely affects reproductive performance such as AI submission rate, pregnancy rate, interval to first AI and first AI conception rate; moreover, an increase or decrease in the BUN levels beyond 15-19.9 mg/dL leads to the AOC postpartum.
        4,000원
        10.
        2021.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Purpose: The aim of this study was to describe and understand the experiences of pain and the perceptions of treatment through a traditional Korean medicine clinical trial in patients with non-acute pain after back surgery. Methods: The data collection was recorded through in-depth interviews with 20 participants and transcribed with verbatim. The data were analyzed with qualitative contents analysis. Results: Patients with persistent or recurring pain after back surgery experienced physical and psychological symptoms that resulted in severe difficulties in daily and working life. Their persistent or recurring pain after surgery was a burden in their life and a major source of depression. Because of the difference in the perception of pain between doctors and patients, the patients continuously sought and received various treatments. The patients also wanted to receive customized self-management in exercise so that they could control pain themselves in daily life. Conclusion: A multidisciplinary approach that includes psychological counseling, pain management, individualized exercise, and education for proper posture should be needed to reduce low back pain in patients with pain after back surgery.
        4,000원
        13.
        2021.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper considers a joint problem for blood inventory planning at hospitals and blood delivery planning from blood centers to hospitals, in order to alleviate the blood service imbalance between big and small hospitals being occurred in practice. The joint problem is to determine delivery timing, delivery quantity, delivery means such as medical drones and legacy blood vehicles, and inventory level to minimize inventory and delivery costs while satisfying hospitals’ blood demand over a planning horizon. This problem is formulated as a mixed integer programming model by considering practical constraints such as blood lifespan and drone specification. To solve the problem, this paper employs a Lagrangian relaxation technique and suggests a time efficient Lagrangian heuristic algorithm. The performance of the suggested heuristic is evaluated by conducting computational experiments on randomly-generated problem instances, which are generated by mimicking the real data of Korean Red Cross in Seoul and other reliable sources. The results of computational experiments show that the suggested heuristic obtains near-optimal solutions in a shorter amount of time. In addition, we discuss the effect of changes in the length of blood lifespan, the number of planning periods, the number of hospitals, and drone specifications on the performance of the suggested Lagrangian heuristic.
        4,200원
        14.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        이끼의 분쇄번식 시, 가장 적합한 배양토, 광, 온도를 구명 하기 위해 날개양털이끼(Brachythecium plumosum)와 쥐꼬리이끼(Myuroclada maximowiczii)를 이용하여 실험을 수행하였다. 실험 개시 4주 후에 사진을 찍어 Photoshop에서 이끼 면적과 녹색 평균값을 구하여 이끼의 생육 정도를 나타내었다. 배양토의 경우, 두 이끼 모두 다스란 상토에서 생육이 가장 좋았고, 상토:마사토(50:50), 원예상토, 마사토:피트모스(50:50) 에서는 비슷한 수준이었다. 버미큘라이트 단용에서는 생육이 부진하였다. 광도실험에서는 날개양털이끼는 25umol・m-2・s-1 에서 100umol・m-2・s-1까지 광도가 높아질수록 생육이 조금씩 좋아지는 경향이었으나, 쥐꼬리이끼는 3개의 광환경에서 비슷한 수준이었다. 온도 실험에서는 두 이끼 모두 23℃에서 면적과 녹색값이 가장 높아 생육도 좋았다. 이러한 결과를 종합 하면, 건조한 이끼를 분쇄하여 번식할 때, 배양토로는 보습력이 좋은 다스란 상토나 원예용 상토가 무난하며, 광도는 25~100umol・m-2・s-1 범위, 온도는 20~23℃가 적당할 것으로 판단된다.
        4,000원
        17.
        2020.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        2019년 경기도내 전통시장, 대형마트, 반찬전문점에서 수거한 반찬류의 미생물 품질을 조사하였다. 반찬류 108 건의 식중독 원인균을 검사하였고, 그 중 75건에 대해서는 구매 장소별, 조리 방법별 위생세균 검사를 진행하였 다. 14건(12.9%)에서 Bacillus cereus가 검출되었으며, 나머지 94건에서는 식중독 원인균이 검출되지 않았다. 위생 세균 검사에서 일반세균의 평균 검출량(범위)은 전통시장이 5.8 log CFU/g (3.0-8.2 log CFU/g), 대형마트는 4.3 log CFU/g(2.3-7.8 log CFU/g), 반찬전문점에서는 3.8 log CFU/g (0.0- 6.9 log CFU/g)로 나타났으며, 구입 장소에 따른 유의적인 차이가 있었다(Ρ <0.05). 전통시장의 일반세균수와 대장균 군은 대형마트, 반찬점과 통계적으로 유의한 차이가 있었고, 생채류, 나물류, 볶음류, 젓갈류, 조림류 순으로 일반 세균수와 대장균군이 높게 검출되었다. 콩나물 무침의 보 관온도별 일반세균수의 변화는 냉장보관(4oC)에서는 72시간 경과에서도 큰 변화가 없었으나, 상온보관(20oC) 및 고 온보관(35oC) 시 구입 후 각각 9시간, 6시간 경과 시 부패의 가능성이 제기되어 구입 즉시 냉장보관 할 것을 권장하며, 제품을 판매하는 시설에서도 냉장보관을 하여야 할 것이다.
        4,000원
        19.
        2020.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        군락 광합성 모델의 도출을 위하여 생육 챔버가 필요하며, 이를 위한 광합성의 효율적인 측정 방법이 필요하다. 본 연구의 목적은 내부 환경 제어가 가능한 생육 챔버를 이용하여 광도 및 이산화탄소 농도 변수를 갖는 로메인 상추(Lactuca sativa L.)의 군락 광합성 곡선을 도출하는 방법을 확립하는 것이다. 실험에 사용한 상추는 식물공장 모듈에서 재배되었으며, 군락 광합성을 측정하기 위하여 아크릴로 제작된 생육 챔버(1.0x0.8x0.5m)를 이용하였다. 첫 번째로, 다음의 두 방법을 적용하여 측정된 군락 광합성 속도를 통해 각 방법의 시정수를 계산하여 비교하였다. 즉, 1) CO2 농도를 고정(1,000μmol·mol-1) 하고 광도를 변화(340, 270, 200, and 130μmol·m-2·s-1) 시키거나, 2) 광도를 고정(200μmol·m-2·s-1)하고 CO2 농도를 변화(600, 1,000, 1,400, and 1,800μmol·mol-1) 시켰다. 두 번째로, 1)과 2)의 방식을 적용하여 군락 광합성을 측정했을 때, 특정 광도(200μmol·m-2·s-1)와 특정 CO2 농도(1,000μmol·mol-1)에서 측정된 군락 광합성 속도 값을 비교하였다. 실험 결과 CO2 농도를 변화시키는 방식의 시정수는 광도를 변화시키는 방식에 비해 3.2배 큰 값을 나타내었다. 광도를 변화시키며 측정할 때 군락 광합성 속도는 1분 이내에 안정되었고, CO2 농도를 변화시킬 경우에는 6분 이상의 시간이 소요되었다. 따라서 광도를 변화시키는 측정 방식이 생육 챔버를 이용하여 작물의 군락 광합성 속도를 측정할 때 적합한 방식임을 확인하였다.
        4,000원
        20.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        To attenuate and control the spread of infectious disease, a body of research has been conducted to generate safe vaccines and to continue national-level surveillance. However, understanding on viability and persistence of avian influenza virus (AIV) in infected carcasses, and effective disposal approaches are still limited up to date. Here, using HA test and RT-PCR, we assessed active status of AIV and degradation of viral RNA in collected specimens at different sites and time points. First, AIV infectivity was recovered until day 2, and viral nucleic acids persisted to day 14 and 21 in inorganic and organic samples, respectively, in sealed vials incubated at room temperature. Second, AIV was totally inactivated in all examined specimens, and viral RNA was not detectable at all time points tested at least one month post-infection in AIV-inoculated carcasses buried directly in soil or fiber reinforced plastic (FRP) bin. Lastly, among different burial sites in South Korea, 6 out of 17 sampling sites in Jeonbuk province showed the presence of viral genetic materials, while the rest of the field samples displayed neither the presence of infective AIV nor detectable viral RNA. This study showed a linear relation between time and degradation degree of viral RNA in buried samples suggesting that burial disposal method is effective for the control or at least attenuation of spread of AI infection in infected animals although consistent monitoring is required to verify safety of disposal.
        4,000원
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