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        검색결과 219

        1.
        2024.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study investigated an appropriate saw-cut time frame for jointed concrete pavements. Rectangular slabs (400–500 × 500 × 150 mm) were prepared for saw-cutting tests, and experimental specimens were made using different mixes (type I cement, slag, Fly ash, high early strength cement, etc.) and temperature curing conditions (10, 20, and 25 ℃ as well as variable field conditions). METHODS : A prototype saw-cut device was manufactured to avoid unwarranted joint cutting using uncontrolled saw-cut equipment. The setting times were determined using Proctor penetration resistance (PR) and Ultrasonic pulse velocity (UPV) tests. The setting times were converted to setting maturities. To link the setting time of the concrete with the initiation time for saw cutting, successive parallel cuts were performed on the rectangular slabs for all mixes. A series of saw-cutting attempts were made between the final setting time and the time when the raveling index (denoted by R) exceeded a value of 2. Reconstructed images of the saw-cut segments were then analyzed using ImageJ, which is a commonly used, open-source software tool. RESULTS : Considering the PR and UPV settings, the final setting of the PR test was adopted as the basis for the correlation curve. The saw-cutting maturity at R = 2 was correlated with the setting maturity of each mix and curing condition. CONCLUSIONS : The relationship between the saw-cutting maturity and setting maturity was represented by a lower limit line, based on the test results of this study. The coefficient of determination (R2) for the test was 0.74, indicating that the proposed PR test at the final setting and image-based techniques provided an optimal method by which to determine the saw-cut initiation time. Another upper limit line can be introduced by using the HYPERPAV software tool for any concrete mix under diverse curing conditions..
        4,300원
        2.
        2024.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Due to climate change and the expansion of cultivation areas through the use of reclaimed land, changes in the selection of Italian ryegrass (Lolium multiflorum L.) varieties are anticipated. This study was conducted to compare the growth characteristics before overwintering, productivity, and feed value of eight Italian ryegrass varieties with different maturing stages under the same cultivation conditions. The variety ‘Lm4ho’, a medium-maturing type, showed superior growth characteristics before overwintering, including plant height, leaf length, and leaf width. The heading date was advanced in all varieties, with a greater degree of advancement observed in varieties with earlier heading dates. When harvested at the heading stage of the early-maturing types, the dry matter yield of the medium-maturing types was not significantly different from that of the early-maturing types. However, when harvested at the heading stage of the medium-maturing types, the dry matter yield was higher than that of the early-maturing types. Specifically, ‘Lm4ho’ produced 2,518 kg/ha more than ‘Kowinearly’. The late-maturing variety IR901 and the medium-maturing varieties ‘Lm4ho’ and ‘Kowinmaster’ showed statistically superior dry matter yields. In terms of forage value, including crude protein (CP), total digestible nutrients (TDN), and relative feed value (RFV), the medium- and late-maturing types outperformed the early-maturing types. Notably, ‘Lm4ho’, ‘IR 901’, and ‘Hwasan 104’ were evaluated as suitable varieties for high-quality forage production. These results suggest that medium-maturing varieties may be suitable for double cropping in the central regions due to climate change. We propose that future breeding of Italian ryegrass should expand from focusing on cold tolerance and early-maturing varieties to include mediumand late-maturing varieties that consider both productivity and quality.
        4,300원
        3.
        2024.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        해방 이후의 시기인 탈식민지기에 들어서면서 일본어교육은 철저히 배 제되었다. 한국어를 국가의 언어로 인정함과 동시에 생활언어와 교육언 어에 있어서 한국어를 되돌리고자, 대한민국 각처에 남아있는 일본어 간 판 및 일본 서적 등 일본어적 색채를 일소시키기 위한 신문화 운동이 일 어났다. 이러한 반일 및 배일 관념의 심화로 인해 일본어교육은 공백기 에 들어갔지만, 장면 정권기, 대(對)일 적극책으로 노선을 변경함에 따라 반일 감정이 조금씩 완화되었다. 이 시기 일본 서적 및 영화 등 일본의 대중문화가 유입되었고 그에 따라 일본어를 배우려는 20대 수요층이 크 게 늘어났다. 전국적으로 일본어 강습소가 우후죽순으로 생겨났고 한일 국교정상화를 앞두고 일본어교육의 필요론을 제기하는 시민들, 개인의 출세를 위해 암암리에 일본어를 학습하는 자들도 많았다. 박정희 정권기 인 1965년 한일기본조약이 체결되면서 양국의 경제교류는 활발해졌고 1973년부터 고등학교 제2외국어로 일본어교과목 지정과 대학에서의 일 본어학과 개설 등이 본격적으로 행해졌다. 이를 통해 국민의 주체의식 확립을 위해 ‘부정’적이었던 일본어교육이 ‘수용’이라는 관념으로 시대적 기능이 전환되었다. 본고에서는 해방 이후 일본어교육의 성행 과정과 양 상을 살펴보고 일본어교육이 성행하게 된 요인과 시대적 기능의 변화를 살펴봄으로써 향후 한국에서 일본어교육이 나아가야 할 방향에 대해 의 미있는 시사점을 찾고자 한다.
        5,500원
        5.
        2024.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the context of a globalized society where diversity, equity, and inclusion (DE&I) have emerged as pivotal values, the fashion industry is undergoing scrutiny for its practices related to body DE&I. This study examines the nature of the discourse surrounding body DE&I within the fashion industry, focusing on how such discussions are shaped, disseminated, and manifested in both the industry and broader society. Critical discourse analysis is applied by utilizing, content from the New York Times and leveraging Fairclough’s analytical framework encompassing textual, discursive, and social practices. The findings indicate that the New York Times emphasizes diversity, with a significant focus on the shapes and sizes of women’s bodies, developing a narrative centered around women’s bodies through visible and representative domains. The analysis suggests conflicted discourse, with prevailing critiques against the fashion industry’s standardization of beauty and superficial inclusivity efforts. Moreover, the industry’s adaptation to social demands for body DE&I is observed as sporadic, often leveraging non-normative bodies as a marketing strategy rather than genuinely embracing diversity. This study highlights the importance of continuous, in-depth discourse and social practices regarding DE&I within the fashion industry, as well as the need for systemic changes and policies that genuinely reflect societal demands for inclusivity. The findings provide a foundation for future investigations into the multifaceted relationship between fashion discourse, DE&I, and social practices, advocating for a more inclusive and critically aware fashion industry.
        5,100원
        6.
        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
        7.
        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
        8.
        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
        9.
        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.
        11.
        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
        12.
        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.
        13.
        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
        15.
        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
        16.
        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
        17.
        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
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