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        검색결과 214

        1.
        2024.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this research, a detailed analysis of the decay heat contributions of both actinides and non-actinides (fission fragments) from spent nuclear fuel (SNF) was made after 50 GWd·tHM−1 burnup of fresh uranium fuel with 4.5% enrichment lasted for 1,350 days. The calculations were made for a long storage period of 300 years divided into four sections 1, 10, 100, and 300 years so that we could study the decay heat and physical disposal ratios of radioactive waste in medium- and long-term storage periods. Fresh fuel burnup calculations were made using the code MCNP, while isotopic content and then decay heat were calculated using the built-in stiff equation solver in the MATLAB code. It is noted that only around 12 isotopes contribute more than 90% of the decay heat at all times. It is also noted that the contribution of actinides persists and is the dominant ether despite decreasing decay heat, while the effect of fission products decreases at a very rapid rate after about 40 years of storage.
        4,000원
        2.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        제충국(Tanacetum cineariaiaefolium), 데리스(Derris elliptica), 고삼(Sophora flavescens) 추출물은 다양한 해충을 방제하는데 사용되고 있다. 하지만, 국내에서 판매되고 있는 식물추춞물 자재는 유효성분의 표기가 없고, 살충농도와 살충시간에 대한 자료가 전무한 상황이다. 본 연구에서는 상 용화된 주요 식물추출물의 살충유효성분의 농도를 결정하고 복숭아혹진딧물에 대해 살충농도와 살충시간을 측정하였다. 식물추출물의 살충활성성분 인 pyrethrins, rotenone, matrine과 oxymatrine의 농도는 액체 크로마토그래피에서 표준물질을 활용하여 질량분석을 통해 측정하였다. 식물추출 물을 농도별로 희석하여 복숭아혹진딧물에 살포하여 살충력을 측정하였다. 표준화합물과 비교한 후 질량분석 및 결정했습니다. Myzus persicae에 대 한 lethal concentation과 lethal time을 조사했다. 살포 후 48시간 후 치사 농도(LC50)는 pyrethrins (20.4 ppm), roteone (34.1 ppm), matrine (29.6 ppm)였고, 100 ppm 살포한 LT50은 pyrethrins (13.4시간), rotenone (15.1시간), matrine (14.4시간)로 측정되었다. Kaplan-Meier 생존분 석 결과, 100 ppm에서 세 가지 식물 추출물의 LT50은 대조구인 화학 살충제인 Sulfoxaflor를 살포 처리구보다 유의하게 빨랐습니다. 본 결과는 복숭 아혹진딧물 방제를 위해 식물추출물의 제형화에 단일 또는 혼합 제제를 개발하는데 기준 살충농도와 살충시간을 제고하는데 의미가 있다.
        4,000원
        3.
        2023.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        압축센스(Compressed SENSE) 기법은 검사 시간을 획기적으로 단축할 수 있으나, 시간 단축을 위한 기법적용 시 가속계수를 증가시키면 인공물의 발생이 영상에서 증가하는 문제점이 있다. 이에 인공물이 발생하지 않으면서 검사 시간을 최대한 단축할 수 있는 최적의 압축센스 가속계수를 제시하고자 하였다. 연구 방법은 인공물이 발생하지 않는 가속계수 1.0을 기준으로 0.5 간격씩 5.0까지 무릎관절 자기공명영상의 팬텀 실험과 임상실험 영상을 획득한 후, 방사선사 10명이 5점 척도로 영상을 평가하여 유의한 차이가 있는지 판단하였다. 연구 결과 T1 강조영상과 T2 강조 영상 모두 팬텀 실험은 가속계수 2.0 이하로 하였을 때 임상실험은 3.0 이하로 하였을 때 기준이 되는 1.0 영상과 차이가 없었다. 결론적으로 무릎관절 자기공명영상 검사 시 인공물이 발생하지 않으며 검사 시간을 최대로 단축할 수 있는 최적의 압축센스 가속계수는 팬텀 실험의 경우 2.0, 임상실험의 경우 3.0이 적정하리라 판단된다.
        4,200원
        4.
        2023.10 구독 인증기관·개인회원 무료
        Botanical extracts are employed in management of aphids. Extracts from Tanacetum cineariaiaefolium, Derris elliptica, and Sophora flavescens are widely used to control various insects. In this study, we determined concentrations of active insecticidal compounds (Ais) in commercial botanical extracts of these plants, and we investigated the time and concentration for lethal results with the green peach aphid, Myzus persicae. The concentrations of Ais, pyrethrins from T. cineariaiaefolium, rotenone from D. elliptica, and matrine and oxymatrine from S. flavescens, were determined after their fractionation by liquid chromatography followed by mass analysis and comparison with standard compounds. The extracts were tested for lethality in a bioassay with green peach aphids. Sprays at defined doses were applied to tobacco leaves infested with aphid nymphs. The lethal concentrations (LC50) were 20.4 ppm for pyrethrins, 34.1 ppm for rotenone, and 29.6 ppm for matrine at 48 h after treatments. At 100 ppm application levels, the lethal time LT50 was 13.4 h for pyrethrin, 15.1 h for rotenone, and 14.4 h for matrine. Kaplan - Meier analysis indicated the lethal times for the three botanical extracts at 100 ppm were significantly faster than application of a chemical insecticide, Sulfoxaflor, applied at the recommended level. These results provide baselines to develop and formulate single or mixed preparations containing botanical extracts to control green peach aphids on commercial crops.
        6.
        2023.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : Most Red bus1) (metropolitan bus) routes to Seoul need to increase supply by increasing the number of buses and number of trips because of the high level of congestion in buses, which also accommodate standing passengers. Due to the recent Itaewon disaster, people have been banned from standing on Red buses due to concerns over the excessive use of public transportation, adding to the inconvenience of passengers, such as increased travel time. However, some routes incur a large deficit owing to excess vehicles and trips relative to the number of passengers, thereby increasing the financial burden of Gyeonggi. Therefore, in this study, a reasonable operation plan is required based on the demand on Red bus routes. METHODS : Using accurate data from smart cards and a Bus Management System, the model was applied to consider bus usage, bus arrival distribution, waiting time, and operating conditions, such as actual bus usage time and bus dispatch interval. RESULTS : As a result of applying the model, buses between 7:00 and 9:00 and 16:00 and 18:00 were very crowded because of standing passengers, and passenger inconvenience costs decreased because of the longer waiting times for bus stops in Seoul. Currently, there are 15 buses in operation for the red bus G8110. However, considering the annual transportation cost, transportation income, and support fund limit, up to 12 buses can be operated per day. The G8110 route was analyzed at 23.6 million won for passenger discomfort cost, as 15 buses operated 97 times per day on weekdays. However, when establishing optimal scheduling, 12 buses per day operated 75 times per day, with a 19.7 million won passenger discomfort cost. CONCLUSIONS : As all red buses run from the starting point, passengers at the bus stop wait for more than an hour before entering Seoul, and the passenger discomfort cost of using demand-responsive chartered buses decreases only when commuting from Jeongja Station and Namdaemun Tax Office stops. Currently, many people commuting from Gyeonggi-do to Seoul are experiencing significant inconvenience owing to the ban on standing in Red buses; a suitable level of input can be suggested for the input and expansion of chartered buses.
        4,200원
        7.
        2023.07 구독 인증기관·개인회원 무료
        Insurance and unit trust (also known as mutual funds) are high-involvement financial products that require investors to hold for long term to gain desired returns. These financial products are also considered unsought products, which require salespeople’s personal touch with their potential customers to make sales. Therefore, the relationship between salespeople and their potential or existing customers becomes crucial in the sales of insurance and unit trust. In theoretical terms, this relationship represents business ties. A strong business ties between the salespeople and the customers enable them to exchange resources and knowledge, and co-create values in their business relationships. Such exchange and co-creation of values are desirable in a business network. Weak ties are irregular and infrequent exchanges, creating structural holes that bring about an opportunity for bridging but have not yet been capitalized.
        8.
        2023.07 구독 인증기관 무료, 개인회원 유료
        Agility involves dynamic capabilities that can adapt to change, reduce complexity, and reconfigure resources. Research on B2B firms' agility in complex international ecosystems is limited. This study explores the essential dynamic capabilities necessary for B2B marketing to enhance organizational agility. Qualitative methods are applied, including focus groups and interviews with managers and officials in various industries. The aim is to contribute to the discussion on B2B firms' capabilities, strategies, and patterns to gain agility in internationalization efforts.
        4,000원
        10.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Chinese land system has gone through several changes since modern times. Although some transformations are only tentative explorations, they have strong practical significance. During the period from 1851 to 1949, it included the National Land System, Sun Yat-sen’s idea of “equal land rights”, Jinggangshan Land Law and Xingguo Land Law during the Agrarian Revolution, as well as Outline of Chinese Land Law during the Liberation War. The changes of the land system has a distinct characteristics, productivity and production relations decide the change of land system in modern China, and the shackles of feudal ideas hindering such changes, moreover spontaneity and compulsory unification has carried out on the basis of the change of land system, while the cause of revolution in modern China emerging from such transformations.Review since modern times of China tell us the history of the land system change, we will improve the system of land laws and regulations, adhere to protect farmers’ interests, strengthen the position of public ownership is not moved, build a new era of agricultural management system can guarantee the healthy and orderly development of China’s land system, thus to promote the rural revitalization of the foundation and guarantee.
        5,200원
        11.
        2022.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was performed to evaluate the quality characteristics and antioxidant activity of Nurungji by varying the purple sweet potato powder addition time (AR: added after rice cooking, BR: added before rice cooking) and powder ratio (0, 2, 4, 6, 8%) on the prepared rice during Nurungji’s manufacturing. In both AR and BR samples, water binding capacity, soluble solid content, reducing sugar, and hardness increased with an increasing proportion of purple sweet potato powder; however, the pH and moisture content decreased. The L value and b value decreased and increased with the influence of anthocyanin in purple sweet potato powder. The total polyphenol, flavonoid, anthocyanin contents, DPPH, and ABTS radical scavenging activity were highest in Nurungji with 8% of purple sweet potato powder. Moreover, AR samples showed higher antioxidant activity than BR samples. Based on the study results above, the preparation of Nurungji with 8% purple sweet potato powder by AR process was more favorable based on the content of antioxidants and antioxidant activity.
        4,000원
        12.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the antioxidant activity of methanol extracts of wheat sprouts grown in wild fields and cultivated fields and harvested at various times were analyzed to compare the quality characteristics of the wheat sprouts as a function of their cultivation and harvest time, as well as for the development of functional materials. The total polyphenolic and flavonoid content, as well as antioxidant activity of the wheat extracts, were subsequently analyzed. The ABTS radical scavenging activity of the wheat extract increased from 16.97 mg TEAC/g sample on cultivation day three in cultivated field wheat sprouts to 25.99 mg TEAC/g sample after seven days of wild field cultivation. The total polyphenol content increased from 17.08 mg GA eq/100 g in cultivated field wheat sprouts grown for three days to 28.70 mg GA eq/100 g after seven days of wild field cultivation. In addition, the flavonoid content increased from 7.02 mg catechin eq/100 g (7 days) to 8.47 mg/g after 12 days of wild field cultivation. Notably, the activity subsequently decreased. These results suggest that the wheat sprouts with higher biological activity were those produced from the wild field after 20 days.
        4,000원
        16.
        2021.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, we investigate the effect of the duration of mechanical alloying on the microstructures and mechanical properties of ODS ferritic/martensitic steel. The Fe(bal.)-10Cr-1Mo pre-alloyed powder and Y2O3 powder are mechanically alloyed for the different mechanical alloying duration (0 to 40 h) and then constantly fabricated using a uniaxial hot pressing process. Upon increasing the mechanical alloying time, the average powder diameter and crystallite size increased dramatically. In the initial stages within 5 h of mechanical alloying, inhomogeneous grain morphology is observed along with coarsened carbide and oxide distributions; thus, precipitate phases are temporarily observed between the two powders because of insufficient collision energy to get fragmented. After 40 h of the MA process, however, fine martensitic grains and uniformly distributed oxide particles are observed. This led to a favorable tensile strength and elongation at room temperature and 650oC.
        4,000원
        17.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It has long been speculated that the visual system should use a coding strategy that takes advantage of statistical redundancies in images. But how such a coding strategy should manifest in neural responses has been less clear. Low-level image structure related to the power spectrum of natural images appears to be captured by a hard-wired efficient code in the retina of the fly and precortical structures like the LGN of cats that maximizes information content through the limited capacity channel of the optic nerve. But visual images are typically filled with higher-order structure beyond that captured by the power spectrum and visual cortex is not constrained by the same capacity limits as the optic nerve. Whether and how visual cortex can flexibly code for higher order redundancies is unknown. Here we show using psychophysical techniques that the neural response in early human visual cortex may be modulated by orientation redundancies in images such that a visual feature that is contained within a predictive pattern results in slower reaction times than a feature that deviates from a pattern, suggesting lower neural responses to predictable stimuli in the visual cortex. Our results point to a neural response in early visual cortex that is sensitive to global patterns and redundancies in visual images and is in marked contrast to standard models of cortical visual processing.
        4,000원
        18.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Steaming is a method that has traditionally been used for medicinal plant extraction. This study investigated nitrite oxide production, ferrous ion chelating activity, α-glucosidase, xanthine oxidase, and acetylcholinesterase inhibitory activities of ethanol, acetone and hot-water extracts of Codonopsis lanceolata prepared by steaming seven times. MTT assay showed that each extract was non-toxic up to a concentration of 700 μg/mL confirming that there was no cytotoxicity in all extracts. The α-glucosidase, xanthine oxidase, and acetylcholinesterase inhibitory activities exhibited by the hot-water extract obtained from steaming seven times were higher (83.1%) than the other extracts. Higher production of nitrite oxide and better ferrous chelating activity was recorded with hot-water extract compared to ethanol and acetone extracts. These results indicated that more steaming of Codonopsis lanceolata extracts would be required to validate the possibility of developing antioxidants. Also, further study is needed to determine if the components present in the tested extracts might be useful in the prevention of Alzheimer's disease. These results showed that hot-water extracts may be useful for their antioxidant and the production inhibitory activity of nitrite oxide. It will be helpful in the investigation of the constituent analysis of the steam-processed product of Codonopsis lanceolata.
        4,000원
        19.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        1970년대 후반 동양화는 일군의 전위적인 작가들과 화단에 진입하기 시작한 신진작가들에 의해 시대정신에 입각한 새로운 전통회화를 수립하기 위한 혁신적인 미술운동이 일어났다. 이러한 과정에서 미술계는 동양화라는 명칭을 한국화로 개칭하고 일제강점기에 유입된 일본 화풍의 배격과 전통 채색기법에 기 반을 둔 새로운 채색화를 만들기 위해 다양한 실험을 시도했다. 이는 1980년대 한국 사회에 불어 닥친 일본 제국주의의 잔재를 청산하고 민족의 정체성을 정립시켜 새로운 국가를 수립하자는 국학운동과 궤를 같이하는 미술운동이었다. 이러할 때 박생광은 1977년 일본에서의 작품활동을 끝내고 귀국하여 그동안 연구해온 민족 정서가 충만한 새로운 채색화를 시도했다. 일제강점기 이후 맥이 끊어진 전통 채색기법과 색채를 시대 감각에 맞게 복원하고 작품 속에 민족 정서를 표현하고자 했다. 이를 위해 그는 사회 전체가 서구 문화에 경도 되어 잊혀 가던 전통 민속 그림과 종교화에서 오히려 모티브를 찾아 작품을 제작하였다. 박생광의 이러한 시도는 당시에 선진 화풍으로 인식된 서양화에 비해 시대정신과 감각이 사회와 이질적으로 멀어지던 동양화를 개혁하여 미술계와 일반 대중들에게 새로운 한국화로서의 가능성을 보여주었다. 특히 한국의 전통미감이 서려 있는 1977년 이후 작품들은 미술사적으로 한국 채색화의 모범으로 인정받았으며 세계로부터도 아시아 미술의 가능성을 제시하였 다고 평가받았다. 1980년대 한국 사회는 군부 집권세력의 타도와 민주주의 건설이라는 대명제를 이루기 위한 민중의 궐기로 매우 혼란스러웠다. 박생광이 1977년부터 1985년에 제작한 여러 유형의 작품 들을 살펴보면 이러한 시대정신을 내포한 다양한 작품들이 존 재한다. 이 작품들은 민주화 운동가들이 제작한 걸개그림과는 결은 다르지만, 순수회화를 지향하는 작가로서 시대의 아픔을 같이하고 기록으로 남기는데 큰 역할을 하였다.
        7,800원
        20.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 시험은 무가온 시설재배 조건에서 북부하이부쉬 블루베리의 전정시기가 영양 생장과 과실 생산에 미치는 영향을 구명하고자 수행되었다. 180L 용기에서 재배한 7-9년생 ‘듀크’ 품종을 대상으로 2018년과 2019년 6월 20일(수확 후 30일경), 7월 20일, 8월 20일에 하계전정을 실시하였고, 2019년과 2020년 1월 20일에 동계전정(관행)을 목질부 생장량의 30%를 제거하는 방법으로 처리하였다. 하계 전정구들은 2년 연속 전정 이듬해인 2020년 10월 15일에 신초 생장이 현저히 감소하였는데, 주당 총 신초장은 6월, 7월, 8월 전정구가 동계 전정구에 비해 각각 47%, 37%, 33%로 작았고 하계전정 시기가 늦을수록 신초 생장이 감소하는 경향이었다. 하계전정 1년 차와 2년차 이듬해의 과실 특성은 전정 시기의 영향이 없었고, 주당 수량은 전정 1년차 이듬해인 2019년에는 차이가 없었으나 2년 연속 처리 이듬해 2020년에는 동계 전정구가 2.9kg인데 반해 하계 전정구들은 동계 전정구에 비해 21~38%가 감소 하였다. 따라서 무가온 시설재배 조건에서 북부하이부쉬 ‘듀크’의 하계 전정은 동계 전정에 비해 수세가 약화되어 수량이 감소할 수 있는 것으로 나타났다.
        4,000원
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