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        검색결과 10,259

        3301.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Modern manufacturing industries is to produce both precise and robust mechanical parts without failure while they are in service. In order to prevent a part failure for its lifetime, a mechanical design for a part should be examined on a basis of mechanical simulation. A nozzle plate, being a key part in steam engines, changes flow directions of steam in a turbine used in power plant. This paper is to the design and test for part safety and durability. Currently, nozzle plates are fabricated by welding nozzles to their plates. Welding causes some defects on the used materials while they are being manufactured. Another major defect is un-even pitches between welded nozzles. Welding causes phase changes because of high melting temperature of metal. This leads to decay on the welding spots, which weakens their structural strength and then, may lead to early damages on mechanical structures. This research proposes assembly-typed nozzle plate without welding. From the beginning, nozzle and plate are designed for insertion-typed assembly. Nozzle head and foot are designed in accordance with the grooves on outer ring and inner ring of a plate to make mating surfaces. Then the nozzle plate should be proved for structural and fatigue safety before they are put in manufacturing. This research adopts commercial softwares for modeling and mechanical simulation. The test result shows that the design with smaller mating area and deeper insertion produces higher safety in terms of structure and durability. From the conclusion, this paper proposes the assembly-typed nozzle plate to replace the welding typed.
        4,000원
        3302.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Humic substances that can be obtained from coal resources such as leonardite in a bulk scale have been employed as crop stimulators and soil conditioners. The polymeric organics containing a variety of aromatic and aliphatic structures are known to activate plants in a multifunctional way, thus resulting in enhanced germination rate and abiotic stress resistance concomitant with induction of numerous genes and proteins. Although detailed structural-functional relationship of humic substances for plant stimulations has not been deciphered yet, cutting-edge analytical tools have unraveled critical features of humic architectures that could be linked to the action mechanisms of their plant stimulations. In this review article, we introduce key findings of humic structures and related biological functions that boost plant growth and abiotic stress resistance. Oxygen-based functional groups and plant hormone-like structures combined with labile and recalcitrant carbon backbones are believed to be critical moieties to induce plant stimulations. Some proteins such as HIGH-AFFINITY K+ TRANSPORTER 1, phospholipase A2 and H+-ATPase have been also recognized as key players that could be critically involved in humic substance-driven changes in plant physiology.
        4,000원
        3303.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        While the term online shopping refers to all online transactions, cross-border online shopping means shopping activities purchasing products or services over the internet for the customers abroad. As Internet use for the international shopping activity increasing, cross border online shopping has grown substantially for last decade. This study is about the problem regarding the cross border online shopping for two different countries and the variables that influence their shopping behavior. The cross border online shopping has been increased by the growth of Internet access. However, the growth of the Internet use does not guarantee a successful development of cross border e-commerce for every country. To find out the perception for cross-border online shopping for two different cultures, shoppers from two countries with different cultural background were chosen, and the perception for cross-border online shopping from each culture is contrasted. For statistical Analysis, ANOVA is used to find the relationship between a single non-metric independent variable, and multiple metric dependent variables. Hofstede’s cultural dimensions model is adopted for this study as a tool to find out the patterns of cross border online shopping. This study showed what the variables would affect the perception in cross border online shopping. The results of this study indicated that cross border online shoppers with different culture were notably different on two variables identified-timeliness and ease of use.
        4,000원
        3307.
        2018.09 구독 인증기관 무료, 개인회원 유료
        Jeju has been transformed into an international city and English has been a significant communication means in Jeju. Since English is essential for globalization, English education in Jeju has become the focus of public attention. The purpose of this study is to examine students' opinions about the effectiveness of college English instruction in the Department of Tourism English in Jeju. Subjects’ perceptions regarding the effectiveness of college English instruction were analyzed in this study. The data showed students generally agreed that native and Korean teachers’ team teaching is helpful (M=4.261), that the courses are practical and useful for the students' career development (M= 3.565), and that generally, English learning in the class is satisfactory (M=3.543). However, students disagreed with the idea that the English courses help students understand foreign cultures (M= 2.935).
        4,000원
        3308.
        2018.09 구독 인증기관 무료, 개인회원 유료
        Aging are both global and domestic issues. In Korea, the population aged 65 and over accounted for 14.8% of the total population in 2018 and 14.4% in Jeju island. The Korea National Statistical Office estimates it will reach 41% by 2060. As the elderly population increases, socioeconomic policy changes and researches on health aging have been carried out especially in developed countries. Representative studies are telomere studies and molecular inflammation. Korean researchers also have made efforts to elucidate the secret of aging including TLR5 (Toll-like receptor 5)/caveolin study in Jeolla province, and ROS (reactive oxygen species) and molecular inflammation in Gyungsang province. However, Research on aging is still underway and research on gut microbiota started in Jeju province, centering on progeria, is expected to give hope.
        3,000원
        3309.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to determine the effect of injection application of pig slurry on ammonia (NH3) and nitrous oxide (N2O) emission from timothy (Phleum pretense L.) sward. The three treatments were applied: 1) only water as a control, 2) pig slurry application by broadcasting, 3) pig slurry application by injection. The pig slurry was applied at a rate of 200 kg N ha-1. Total NH3 and N2O emission, expressed as a cumulative amount throughout the measurement time (40 days), was 2.68 kg NH3-N ha-1 and 6.58 g N2O-N ha-1, respectively, in the control. The injection application of pig slurry decreased total NH3 and N2O emission by 39.8% and 33.3%, respectively, compared to broadcasting application of pig slurry. The present study clearly showed that injection application exhibited positive roles in reducing N losses through NH3 and N2O emission.
        4,000원
        3310.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Phalaenopsis ‘Blanc Rouse’ 품종은 국립원예특작과학원에서 2013년도에 육성한 신품종이다. 이 품종은 2007년에 백색 바탕에 분홍색의 소형 P. ‘KV 600’ 품종을 모본으로 하고 진한 핑크색의 P. ‘Kang 1’ 품종을 부본으로 교배시킨 후대 계통 중에서 선발하였다. 2010년에 화색, 초장, 화경 및 식물체의 생육상태 등을 고려하여 1차 선발 후 2013년에 2차 특성검정을 통하여 품종의 안정성과 균일성을 확인하고 ‘Blanc Rouse’로 명명하였다. 이 품종은 흰색바탕에 자주색 순판을 가졌으며 꽃 가운데 분홍색의 줄무늬가 크게 형성되어 있는 품종이다. 화형은 꽃잎과 꽃받침이 평편한 모양이고 꽃의 길이와 폭은 4.3cm, 4.8cm로 소형이다. 꽃대가 평균 2개 발생하며 복총상 화서로 화서당 꽃 수가 39.4개로 볼륨이 있어 소형분화에 적합하다. 자연 개화시기는 11월 하순으로 개화가 빠른 조생종 이다. 잎의 길이와 폭은 각각 17.3, 6.2cm이며 엽형은 수평이다. 기내 증식력이 높고 변이가 거의 없으며 내병성이 강하여 재배관리가 용이하다.
        4,000원
        3311.
        2018.09 구독 인증기관 무료, 개인회원 유료
        Resveratrol (3,4',5,-trihydroxystilbene), a phytoalexin present in grapes, exerts a variety of actions to reduce superoxides, prevents diabetes mellitus, and inhibits inflammation. Resveratrol acts as a chemo-preventive agent and induces apoptotic cell death in various cancer cells. However, the role of resveratrol in odontoblastic cell differentiation is unclear. In this study, the effect of resveratrol on regulating odontoblast differentiation was examined in MDPC-23 mouse odontoblastic cells derived from mouse dental papilla cells. Resveratrol significantly accelerated mineralization as compared with the control culture in differentiation of MDPC-23 cells. Resveratrol significantly increased expression of ALP mRNA as compared with the control in differentiation of MDPC-23 cells. Resveratrol significantly accelerated expression of ColⅠmRNA as compared with the control in differentiation of MDPC-23 cells. Resveratrol significantly increased expressions of DSPP and DMP-1 mRNAs as compared with the control in differentiation of MDPC-23 cells. Treatment of resveratrol did not significantly affect cell proliferation in MDPC-23 cells. Results suggest resveratrol facilitates odontoblast differentiation and mineralization in differentiation of MDPC-23 cells, and may have potential properties for development and clinical application of dentin regeneration materials.
        4,000원
        3312.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        기후변화는 곤충의 성장, 발육, 생존, 생식력, 분포범위 등 생활사의 변수들에 영향을 준다. 특히 외래곤충의 경우 생태계 정착 및 확산이 빨라 지고 있으며, 생태계 교란, 토착종 감소 등 생물다양성을 감소시키는 직접적인 원인 중 하나이다. 알팔파바구미는 1990년대 제주도에서 처음 발견 후 남부지방에 대량 발생하여 농업해충으로 인식되었다. 최근 하면처로 이동하는 개체에 의한 밭작물의 피해와 여러 시군에서 서식이 확인되며 확산의 우려되고 있다. 본 연구에서는 기후변화가 알팔파바구미에 미치는 영향에 대해 파악하였다. 미래의 기후 시나리오 RCP 4.5와 RCP 8.5에서 알팔파바구미의 잠재적 분포를 추정하기 위해 MaxEnt 모델을 적용하였다. 모형의 변수는 2015~2017년까지 알팔파바구미의 서식이 확인된 66개 지점과 종의 생태특성 및 예측변수간 상관성을 고려한 6개(bio3, bio6, bio10, bio12, bio14, bio16)의 생물기후를 사용하였다. 예측된 모형의 적합 도는 평균 0.765로 잠재력이 의미 있는 값이며, 최고 따뜻한 분기의 평균기온(bio10)이 60~70%로 높은 기여도를 나타냈다. 2050년과 2070년의 시나리오(RCP 4.5, RCP 8.5)에 대한 모형의 결과는 한반도 전역에서 알팔파바구미의 분포 변화를 보여 주었으며, 기온상승에 따른 전국적 확산이 예측되었다.
        4,000원
        3313.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        대부분의 자동관수시스템 기술은 생산측면에서의 원예산물 효율적 재배에 초점을 맞추고 있으나, 화훼식물의 관상가치를 유지하며 효율적으로 식물을 유지 관리하는데 적용될 수도 있다. 이에 본 연구는 실내 조경식물로 많이 이용되고 있는 산호수(Ardisia pusilla)의 관상가치를 유지하기 위한 최적의 용적수분함량(volumetric water content, v/v) 조건을 알아보기 위하여 실시되었다. 토양수분센서와 데이터로거를 이용한 자동관수시스템으로 처리구별 상토 용적수분함량을 0.3, 0.4, 0.5 및 0.6m3・m-3으로 유지하도록 하였으며, 처리 당일과 처리 1, 2, 4주 후에 초장, 초폭, 엽수, 엽면적, SPAD, 잎 수분함량, 생체중, 건물중, 광합성률 및 엽록소 형광과 각 화분의 관수량을 측정하였다. 상토 용적수분함량 처리 1주일 후에는 처리에 따른 생육 및 생리 반응의 차이를 보이지 않았으나, 처리 2주일 후에는 가장 낮은 용적수분함량인 0.3m3・m-3 처리구에서 다른 처리구에 비해 낮은 Fv/Fm 값을 나타냈다. 처리 4주일 후에는 처리에 따른 생리 반응 차이를 보이지 않았으나 초폭, 지상부 생체중, 지상부 건물중, 엽수, 엽면적과 같은 생육 반응은 가장 낮은 용적수분함량 처리구에서 감소하였다. 본 실험 결과를 통해 산호수는 생육 반응에 비하여 생리 반응이 비교적 빠르다는 것을 확인할 수 있었다. 또한 0.5m3・m-3 처리 구의 관수량이 가장 많았으며, 처리구와 관계없이 관수량은 지상부 생체중에 비례하는 것으로 나타났다. 종합적으로 살펴보았을 때, 0.4m3・m-3 처리구에서 산호수의 관상가치가 우수하게 유지되었고, 이를 통해 효율적이고 용이한 물관리가 가능하므로 실내에서 산호수 생육시 0.4m3・m-3 수준의 상토 용적수분함량이 가장 적절한 것으로 판단된다.
        4,000원
        3314.
        2018.09 구독 인증기관·개인회원 무료
        In this experiment comparison was made for the agronomic characteristics and quality of forage rye among the different growing stages. Rye was harvested every 5 days, then separated into three parts and determined the quality. Before harvesting, plant height and yield were recorded. Dry matter yield increased continuously, while fresh matter yield decreased after heading. ADF and NDF value increased before blooming and then showed a slight fluctuate. In addition, highest CP content appeared on jointing stage. TDN and RFV went down until blooming stage and then showed a steady trend. So the proper harvest time is from heading to blooming stage for forage rye.
        3316.
        2018.09 구독 인증기관 무료, 개인회원 유료
        Taste is closely related to intake of food. Taste perception is also influenced by type of food ingested, and nutrition and health status. Bitter taste plays an important role in the survival of human and animals to avoid probable toxic and harmful substances. Vertebrate animals recognize bitter taste through type 2 taste receptors (T2Rs). Several T2Rs have been expressed extra-oral such as the gastrointestinal tract, respiratory tract, urogenital tract, brain and immune cells, and parts of their functions are being revealed. This review will discuss physiological roles of T2Rs in relation to innate immunity, secretion and smooth muscle contraction expressed in extra-oral cells and tissues, and we summarize relationships between polymorphisms in T2Rs and general or oral diseases. It is not a coincidence that animals pay much genetic costs for taste and smell during evolution.
        4,000원
        3317.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 식용화 팬지의 UV-B 주·야간 처리에 따른 항산화물질 변화와 생장반응을 알아보고자 수행되었다. 식용화 팬지(Viola comuta ‘Purple’, ‘Blue’)를 대상으로 인공 재배기에서 광원을 LED(백색) 120μmol·m-2s-1로 16시간으로 하였으며, 자외선 UV-B(310~320nm)처리는 기존연구에서 UV-B처리 효과가 좋았던 20분을 주간(11:50~12:10)과 야간(23:50~00:10)으로 처리하였다. 처리 결과, 두 품종 모두 대조구와 UV-B 주·야간 처리간의 꽃과 잎의 생체중 및 건물중은 유의한 차 이가 없었으며, ‘Blue’의 야간 UV-B 처리를 제외한 모든 처리구에서 꽃수도 유의차가 없었다. 처리 후 1, 3, 5주차에 분석한 결과, 잎의 엽록소함량은 ‘Purple’의 3주차를 제외한 모든 처리구에서 유의차가 없었으며, 두 품종 모두 Fv/Fm과 NPQ(Non Photochemical Quenching)값이 처리 간 유의차가 없었다. 또한 UV-B 처리 5주차에 활성산소(superoxide, O2 -)의 Nitrotetrazolium blue chloride(NBT) 염색 후 현미경으로 관찰한 결과, 처리 간 차이가 없었다. 항산화물질인 총 플라보노이드 함량을 분석한 결과, ‘Purple’은 3주차까지 대조구보다 주간 UV-B 처리구가 많은 것을 알 수 있었고, ‘Blue’의 경우 5주차까지 유의차는 없었지만 주·야간 UV-B 처리구가 대조구에 비해 높은 것을 알 수 있었다. 안토시아닌 함량은 ‘Purple’의 경우 3주차만 제외하고 야간 UV-B 처리구가 가장 높은 것을 알 수 있었으나, ‘Blue’의 경우 처리 간 유의차가 없었다. 결론적으로, 주·야간 UV-B 20분처리는 팬지 ‘Purple’과 ‘Blue’의 생장에 거의 영향을 주지 않았으며, ‘Purple’의 총 플라보노이드 함량은 처리 3주까지 증가하였다.
        4,000원
        3318.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this plan is to regenerate by improving the overall residential environment, that create harmony with the fine natural environment The planning method is to review the current status, draft the basic concept, and set detailed plans by sector. Each process is planned to be implemented based on local residents’ participation. The major content of the plan is as follows. First, the use district that is the biggest obstacle for housing rehabilitation was changed into a residential zone from a green zone, and accompanied by street network planning and organization that is essential for an area’s designation as a residential district. Second, district units plan and landscape guidelines were established to enable construction of special buildings with windows facing east that allow a view of the Mangyeong River. Third, a landscape refinement project surrounding Mangyeonggang-ro was set as the key project, to improve the image of the village and pursue common interests in the community of local residents. Fourth, business facilities, rental housing, and residents’ community facilities for young people are comprehensively planned in the downtown area, which has been declining because of the closing of the bus terminal, to reanimate the community’s landmarks, in terms of both function and space. Fifth, the project pursues regional economic regeneration from promotion of tourism based on full utilization of the landscape of the Mangyeong River, which is a local asset. The planning is conducted in a way that enables the refined residential area to work as another tourism resource. Sixth, unused and less used national owned land is actively utilized to allow for a smoother implementation of the project. In addition, plans to reinforce residents’ capabilities, to develop in connection with the KAB, and HUG are pursued, so that the implementation of the project can be led by local residents.
        4,200원
        3319.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        지난 5년 동안 HMD(Head Mounted Displays)가 개발되어 사람들이 가상현실을 통해 게임에서 몰입형 콘텐츠를 즐길 수 있게 되었다. 이러한 시각을 위한 장치인 HMD는 널리 보급되어 사용되고 있지만, 가상현실에 사용자의 입력을 제공하는 장치는 아직 표준화되지 않았다. 그 결과 다양한 유형의 대화형 장비들 (Leap Motion, Marker-Based Devices 등)이 각자의 장단점을 가지고 개발되어 현재 사용 중에 있다. 예를 들어, Leap Motion은 손동작만 추적할 수 있으며 마커 기반 장치는 사용자와 추적 카메라 사이에 장애물이 있거나 어두운 환경의 경우 동작의 추적에 어려움이 있다. 착용형 모션 캡처는 신체에 착용되는 상호 작용 장치이며 인간과 카메라 사이에 장애물이 있어도 움직임을 추적할 수 있는 장점이 있다. 본 논문에서는 가상현실을 위하여 연구/ 개발된 상호작용 방법들을 설명하고 축구 게임을 통해 검증한다. 우리가 아는 한 본 연구는 착용형 모션 캡쳐를 가상현실 게임에 적용한 세계 최초의 연구이다.
        4,000원
        3320.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to analyze the efficiencies of project management offices in large information system construction projects using the data envelopment analysis. In addition, we tried to estimate the confidence interval of those efficiencies using bootstrap DEA to give a statistical meaning. The efficiency by the CCR model is analyzed as eight project management offices are fully efficient and 22 project management offices are inefficient. On the other hand, there are 15 project management offices are fully efficient, but 15 project management offices are inefficient in the BCC model. As the result of the scale efficiencies, of the inefficient project management offices, 13 project management offices are inefficient in scale. It is possible to eliminate the inefficiency in the CCR model by improving their project performances. And, the nine project management offices showed that the inefficiency was due to pure technical efficiency, and these companies should look for various improvements such as improvement of project execution system and project management process. In order that the inefficient project management offices be efficient, it is analyzed that more efforts must be made for on-budget and on-time as a result of examining the potential improvement potentials of inefficient project management offices.
        4,200원