검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 498

        41.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Climate change due to global warming causes a rise in atmospheric air temperature to rise and extreme shift in precipitation patterns. Carbon dioxide (CO2) is widely known as one of the major cause of global warming and accounts for about 72% of total greenhouse gas emissions. Agriculture is more vulnerable to climate change than other industries. Many studies have been conducted to investigate how agroecosystems, both natural and controlled, will respond to the rising level of CO2. Studies on the responses of crops and agricultural environments to climate change are crucial in predicting changes in agro-ecosystems. Research facilities for various types of CO2 treatment have been developed. The representative research facilities are SAR (Soil-Plant-Atmosphere-Research), OTC (Open Top Chamber), FACE (Free Air CO2 Enrichment System), and TGC & CTGC (Temperature Gradient Chamber & CO2-Temperature Gradient Chamber). Therefore, this study reviewed research data and their application in agriculture.
        4,000원
        45.
        2022.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        살리실산은 식물의 생장 및 발달, 항산화 방어기작, 광합성 작용 그리고 생물적 및 비생물적 스트레스 조건에서 다양한 생리적 기능을 조절하는 물질로 알려져 있다. 본 연구에서는 고온・건조 스트레스 조건에서 살리실산 경엽처리가 고추의 생육, 광합성 특성 및 항산화효소 활성에 미치는 영향을 구명 하고자 하였다. 광합성 특성 측정결과 광합성 속도, 기공전도 도 및 증산 속도가 증가하였고, 3회차 처리에서 가장 높았다. 세포내 MDA와 H2O2 함량은 살리실산 3회차 처리에서 현저 하게 감소하는 경향을 보였다. APX, CAT, POD 및 SOD 활 성이 현저하게 증가하였으며, 무처리 대비 최대 247, 318, 55 및 54% 증가하였다. 고추의 생육 특성은 무처리구와 유의한 차이를 보이지 않았으나, 상품 수량은 15% 정도 증가하였다. 이러한 결과들을 종합해 볼 때, 살리실산의 경엽처리는 고추 의 광합성 특성과 항산화효소 활성을 증진시켜 고온・건조 스트 레스에 의한 피해 경감에 긍정적 효과를 유발함을 확인하였다
        4,000원
        46.
        2022.10 구독 인증기관·개인회원 무료
        For highly contaminated elements such as reactor pressure vessels or reactor internals, it is a viable option to cool-down and dismantle these elements in submerged (e.g. underwater) state. Several tools and processes such as saw cutting, water jet cutting or plasma cutting are currently used for underwater cutting, with each of them having their own advantages and disadvantages. The main disadvantage of these existing methods, especially saw and water jet cutting, is the generation of secondary waste that then needs to be filtered out of the water. In addition, in the case of water jet cutting, a considerable amount of abrasive material is added, which must also be stored. To overcome this drawback, the feasibility of using laser cutting under water to minimize secondary waste production has been actively studied recently. One of the challenges with the underwater laser cutting is to visually monitor the cutting process. Flowing air bubbles generated by the cutting gas and the flashing light emitted from the laser and melting material prohibit visual monitoring of the cutting process. This study introduces a method to enhance the video from a monitoring camera. Air bubbles can be detected by computing optical flows and the video quality can be enhanced by selective removal of the detected bubbles. In addition, suppressing the frame image update from flashing light area can also effectively enhance the video quality. This paper describes the simple yet effective video quality enhancement method and reports preliminary results.
        48.
        2022.09 구독 인증기관·개인회원 무료
        Sustainable capacity building of the rice value chain in Africa is essential in achieving the rice self-sufficiency and poverty alleviation. The breeding capacity enhancement has also been at the heart of AfricaRice’s mandate. Therefore, the Korea-Africa Food and Agriculture Cooperation Initiative (KAFACI) has concentrated breeding capacity enhancement for young breeders or breeding technicians of national research institutes in the KAFACI member countries. Four-month trainings have been conducted at the Regional Training Center located in Saint Louis, Senegal. The actual practice training is as follows; First is to learn practical skills and techniques of key aspects of rice breeding which are field preparation and layout, sowing, transplanting, fertilizer application, weed control, water management, hybridization/crossing, selection, yield and yield components determination, and rice palatability testing. Second is to learn some theoretical aspects of plant breeding through lectures including basic principles of breeding, evaluation for biotic and abiotic stresses, and statistical analysis. Third is to learn about the accurate use of field and lab equipment for rice breeding. Forth is to learn about proper scientific reporting and presentation. The courses were organized twice per year following two rice cultivation seasons in Senegal. From 2019, a total of 24 trainees participated in the 4 month courses. We believe they have acquired the basic knowledge and skills to implement rice breeding activities indpendently in their countries.
        50.
        2022.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Rapid development of carbon nanotubes (CNTs) reinforced to polymer composites has been recently noticed in many aspects. In this work, the latest developments on fatigue and fracture enhancement of polymer composites with CNTs reinforcement with diverse methods are thoroughly compiled and systematically reviewed. The existing available researches clearly demonstrate that fatigue fracture resistance of polymer composites can be improved accordingly with the addition of CNTs. However, this work identifies an interesting research gap for the first time in this field. Based on the systematic reviewing approach, it is noticed that all previously performed experiments in this field were mostly focused upon studying one factor only at a time. In addition, it is also addressed that there were no previous studies reported a relationship or effect of one factor upon others during examining the fatigue fracture of carbon nanotubes. Moreover, there was no adequate discussion demonstrating the interaction of parameters or the influence of one parameter upon another when both were examined simultaneously. It is also realized that the scope of the conducted fatigue fracture studies of carbon nanotubes were mainly focused on microscale fatigue analysis but not the macroscale one, which can consider the effect of environment and service condition. In addition, the inadequacy of fatigue life predicting models via analytical and numerical methods for CNT-reinforced polymer composites have also been highlighted. Besides, barriers and challenges for future directions on the application of CNT-reinforced polymer composite materials are also discussed here in details.
        4,600원
        52.
        2022.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this paper is to propose part management and standardization to reduce cost and increase compatibility of parts through standardization and standardization of parts to be applied to urban air mobility(UAM) systems, Personnel Air Vehicle(PAV), Vertical Take-Off and Landing (VTOL), and so on. In other words, parts used in the urban air transportation system must be verified from the initial design stage in accordance with the aviation standard, and a systematic management system for various parts must be established to secure stability and improve quality. Therefore, as a system similar to the aviation component management system, it should be thoroughly managed for urban aviation components.
        4,000원
        53.
        2022.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Thermoelectric materials can reversely convert heat and electricity into each other; therefore, they can be very useful for energy harvesting from heat waste. Among many thermoelectrical materials, SnSe exhibits outstanding thermoelectric performance along the particular direction of a single crystal. However, single-crystal SnSe has poor mechanical properties and thus it is difficult to apply for mass production. Therefore, polycrystalline SnSe materials may be used to replace single-crystal SnSe by overcoming its inferior thermoelectric performance owing to surface oxidation. Considerable efforts are currently focused on enhancing the thermoelectric performance of polycrystalline SnSe. In this study, we briefly review various enhancement methods for SnSe thermoelectric materials, including doping, texturing, and nano-structuring. Finally, we discuss the future prospects of SnSe thermoelectric powder materials.
        4,000원
        57.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Carbon quantum dots (CQDs) as a rising class of carbon family have gained widespread attention in view of their multiple properties such as great photoluminescence (PL) properties, facile synthesis route, needing economical and cheap raw material, high physiochemical stability, and simple functionalization. This makes CQDs highly versatile and with potential for different applications. To date, CQDs-enabled photocatalysts are regarded as one of the most efficient technologies to degrade pollutants in water; however, poor activity under visible light and the recombination of photogenerated electron and hole pairs hinder getting an ideal performance that may be applied on a large scale. Conventional techniques have been modified via a new advanced method. In this review, we highlighted the strategies to improve the activity of conventional semiconductor photocatalysis via coupling with CQDs, and strategies to improve the photocatalytic activity such as functionalization, doping, and Z-scheme heterojunctions were discussed in detail. This review also covered the CQDs heterojunction application in pollutant degradation and discussed several examples with high-performance photocatalytic activity.
        5,100원
        58.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 발효노니를 건강기능식품 소재로 활용 시 기초자료로 제공하고자 발효노니 추출물 및 지표성분의 면역활성 증진 효과를 평가하였다. RAW 264.7 대식세포 에서 발효노니 추출물 및 지표성분 6종을 처리하여 XTT 세포독성평가, Nitric Oxide 생성 측정, Cyokine 생성 측 정, immune marker genes 발현분석 수행하였다. 뿐만 아 니라 양성대조군으로 LPS와 기능성 원료로 사용되고 있 는 발효홍삼 추출물을 사용하였다. 그 결과 모든 처리 농 도 및 처리군에서 세포독성이 관찰되지 않았으며, 지표성 분 6종 중 SCP 및 ASE에서 NO 생성이 증가됨을 확인하 였다. 뿐만 아니라 ASE 처리군에서는 IL-6 및 IL-1β의 생 성이 증가되었으며, iNOS 및 TNF-α의 immune marker genes 발현이 증가됨을 확인하였다. 발효노니 추출물 효능 평가에서는 발효시 NO 생성 및 IL-6, IL-1β의 생성, COX2 의 발현이 증가되는 것으로 나타났다. 이러한 연구 결과 는 발효노니 추출물 및 지표성분의 선천면역 활성증가를 타나내며 노니 및 발효노니 표준화 연구에서 지표성분으 로 사용 가능성을 제시한다. 따라서 발효노니는 면역증진 활성을 갖는 제품 개발에 있어서 유용한 기능성 식품소재 로써 사용될 수 있으며, 우수한 효능을 나타내는 지표성 분은 유용성분으로 이용이 가능할 것으로 사료된다.
        4,000원
        59.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This in vitro study investigated the enhancement of rumen bacterial adhesion on a substrate to increase the digestibility of rice straw in Hanwoo cattle. The rice straw was pretreated with enzymes, probiotics, or ammonia, and the effects on the enhancement of bacterial adhesion and fiber degradation were analyzed using in vitro rumen fermentation. Enzyme treatment included spraying of cellulase and xylanase at 40 and 120 U per g of rice straw, respectively; Saccharomyces cerevisiae culture of 1.0×107 CFU was sprayed as a probiotic treatment per gram of rice straw; ammonia was sprayed at 0.3% per gram of rice straw. Following enzyme treatment, Fibrobacter succinogenes formed a higher adhesion colony than the control group (7.26±0.03 and 8.43±0.20) after 6h and 12h of in vitro culture (p<0.05), respectively. Attachment of Ruminococcus flavefaciens also increased following enzyme treatment (p<0.05) after 6 and 12 h compared to that of the control (5.18±0.06 and 6.60±0.15); and R. albus attachment showed a significant increase compared to that of the control (5.94±0.15) after 6 h of incubation (p<0.05). Probiotic treatment increased attachment of F. succinogenes in comparison with untreated rice straw after 6 h and 12 h of fermentation (p<0.05); R. flavefaciens attachment showed an increase only after 6 h of culture (p<0.05); R. albus was not affected. Attachment of F. succinogenes, R. flavefaciens, and R. albus increased with ammonia treatment after 6 h and 12 h (p<0.05). Dry matter digestibility was higher after the enzyme treatment (3.45±0.21 and 7.04±0.09) than in the control group(1.85±0.08 and 3.94±0.04) after 6 and 12 h of in vitro culture (p<0.05), respectively. It was also higher than that of untreated rice straw after probiotic and ammonia treatments (p<0.05). There was an increase in the enhancement levels of bacterial adhesion depending on the type of fibrolytic bacteria following enzyme, probiotic, and ammonia treatment. These treatments improved digestibility. This enhancement is considered to be greater following enzyme and ammonia treatments than with probiotics.
        4,300원
        60.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        1. 본 연구는 한국-미얀마 농업분야 개발협력(ODA)의 지속 가능성 강화 방안을 분석하기 위해 2001~2017년 시계열(time series)자료를 토대로 자기회귀분포시차 모델(Autoregressive Distributed Lag, ARDL)방법과 최소자승법(Ordinary Least Square, OLS)을 사용하였다. 2. 분석결과 1) 미얀마 농업 개발에 지원된 국제사회의 ODA, 한국이 지원한 농업 분야 ODA, 농촌 개발에 대한 한국 ODA 등의 변수가 미얀마의 농업 GDP에 긍정적으로 기여한 반면, 2) 한국 ODA는 가치사슬 분야 및 기술전수 분야에 미친 영향이 부정적으로 나타났다. 이는 이 분야의 지원 규모가 매우 작아 미얀마 농업발전에 미친 영향을 측정하기 어렵기 때문인 것으로 해석할 수 있다. 또한 한국이 미얀마에 제공한 농업 ODA 중 농산물 생산 및 유통 분야에 대한 지 원은 영향이 미미한 것으로 나타났으나 양(+)의 영향을 나타 내었다. 3. 분석 결과 한국의 미얀마 대상 농업 분야 ODA는 선택과 집중을 토대로 미얀마 농업 발전에 긍정적인 영향을 미치고 있는 농촌개발 분야에 장기적으로 지원을 확대할 필요성이 있음을 확인하였다.
        4,000원
        1 2 3 4 5