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        검색결과 984

        682.
        1990.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Korean economic growth in exports has been phenomenal in the past two decades. This paper deals with a series of export studies of small- and medium-sized manufacturing firms in Korea which look at export behavior and the conditions which influence export sales in these firms. Profiles of the firms are provided, in addition to discussions of the key influences on initiating exports, channels selection, profitability, and attitudes toward exporting.
        4,900원
        685.
        1976.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        벼를 가해하는 4종의 멸구매미충 즉 애멸구, 끝동 매미충, 벼멸구 및 흰등멸구의 경제적 중요성에 대한 지역적 차이를 수원과 남부 그리고 남서 해안지역에서 수행한 개체군의 밀도조사를 토대로 분석 검토하였다. 한국에서 년중 볼 수 있는 애멸구와 끝동 매미충의 경제적 중요성은 중부지방이 덜한 것으로 보인다. 이는 겨울의 추운 기후조건, 벼, 보리의 경작 방법 및 거미류 같은 천직에 의해서 지연 치사작용이 효과적으로 일어나는 때문인 것으로 믿어진바. 그러나 남부지방에서는 겨울이 덜 춥고 벼, 보리의 경작방법이 이 두 해충의 생활환과 기주식물의 계절적 변천 양자의 재일성에 유리한 편이어서 이들의 경제적 중요성은 확실히 크다고 하겠다. 한국에서 원동을 하지 못하는 벼멸구와 흰등멸구의 매년 첫 발생개체군은 동지나해를 건너 원거리를 이동해 오는 것들에 기인된다. 이들의 이동과 관련을 갖고 있는 기상요소로 해서 이동되어오는 벼멸구와 흰등멸구의 양은 중부지방보다 남부지방에서 월등히 많다. 그러므로 벼를 가해하는 멸구매미충류에 대한 종합방제책으로 중부와 남부지방 별로 지침을 달리 세울 것이 요망된다.
        4,900원
        686.
        1976.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        According to distribution maps of pests published by the Commonwealth Institute of Entomology, in 1969, codling moth occurs in Korea. However, it has never been found in Korea, and it is thought this record is due to a misunderstanding of the literature.
        3,000원
        687.
        1971.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 시험은 우리나라에서 발생하는 푸른곰팡이병균의 종의 빈도와 발병환경 및 방제법을 구명코져 실시하였다. 시험결과 Trichoderma koningi, T. lignorum, T. glaucum과 미동정의 1종등 4종의 병원균이 분리되었고 이들의 빈도는 각각 와 이었다. 푸른곰팡이병균은 감자배양액, 왁스만배양액과 리차드배양액에서 생육이 잘 되었으며 중성-염기성배지에서는 생육이 불량한 반면 산성에서 생육이 왕성하였으며 최적산도는 pH4였다. 양송이 수확기간 중 재배사내의 온도는 내외 일 때 본명의 발생이 적었고 수량이 많으며 이상에서는 본병의 발생이 격심하였다. 푸른곰팡이병균은 복토흙 소독시 에서 60분, 혹은 에서 30분간 열처리하므로서 완전히 사멸하였고 퇴비 후발효 과정에서도 사멸되었다.
        4,000원
        688.
        2021.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        GLONASS, a satellite navigation system developed in Russia since 1976, is defunct and orbits in an unstable attitude. The satellites in these problems are not managed and there is no precise information, which can increase the risk of collisions with other space objects. In this study, detailed attitude dynamic have to be analyzed through photometry data, which requires spin period and spin axis. The light curve data is obtained by observing through the photometer at the Graz station and the power spectrum is calculated to obtain the cycle of the satellite. The geometric relationship between observer and sun is analyzed for GLONASS-50 satellite. The box-wing model is applied to obtain the phase reflection of the satellite and obtain the Irradiation of the satellite through this information. In Light Curve and Irradiation, the spin axis is calculated for each peak points with the distance square minimum technique. The spin axis of the GLONASS-50 satellite is RA = 116°, Dec = 92°.
        689.
        2021.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        In this paper, we present observations of the Space Radiation Detectors (SRDs) onboard the Next Generation Small Satellite-1 (NEXTSat-1) satellite. The SRDs, which are a part of the Instruments for the study of Stable/Storm-time Space (ISSS), consist of the Medium-Energy Particle Detector (MEPD) and the High-Energy Particle Detector (HEPD). The MEPD can detect electrons, ions, and neutrals with energies ranging from 20 to 400 keV, and the HEPD can detect electrons over an energy range from 0.35 to 2 MeV. In this paper, we report an event where particle flux enhancements due to substorm injections are clearly identified in the MEPD A observations at energies of tens of keV. Additionally, we report a specific example observation of the electron distributions over a wide energy range in which we identify electron spatial distributions with energies of tens to hundreds of keV from the MEPD and with energy ranging up to a few MeV from the HEPD in the slot region and outer radiation belts. In addition, for an ~1.5-year period, we confirm that the HEPD successfully observed the well-known outer radiation belt electron flux distributions and their variations in time and L shell in a way consistent with the geomagnetic disturbance levels. Last, we find that the inner edge of the outer radiation belt is mostly coincident with the plasmapause locations in L, somewhat more consistent at subrelativistic energies than at relativistic energies. Based on these example events, we conclude that the SRD observations are of reliable quality, so they are useful for understanding the dynamics of the inner magnetosphere, including substorms and radiation belt variations.
        690.
        2020.12 KCI 등재 서비스 종료(열람 제한)
        The green synthesis of inorganic nanoparticles (NPs) using biomaterials has garnered considerable attention in recent years because of its eco-friendly, non-toxic, simple, and low-cost nature. In this study, we synthesized NPs of noble metals, such as Ag and Au using an aqueous extract of a marine seaweed, Ecklonia cava. The formation of AgNPs and AuNPs was confirmed by the presence of surface plasmon resonance peaks in UV-Vis absorption spectra at approximately 430 and 530 nm, respectively. Various properties of the NPs were evaluated using characterization techniques, such as dynamic light scattering, transmission electron microscopy, energy-dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction analysis. Phytochemicals in the seaweed extract, such as phlorotannins, acted as both reducing and stabilizing agents for the growth of the NPs. The green-synthesized AgNPs and AuNPs were found to exhibit high catalytic activity for the decomposition of organic dyes, including azo dyes, methylene blue, rhodamine B, and methyl orange.
        691.
        2020.12 KCI 등재 서비스 종료(열람 제한)
        In this study, we were performed to elucidate the antioxidant and anticancer activity by leaves extracts from Acer tegmentosum (AT-L). In DPPH, ABTS radical scavenging activity, the AT-L revealed the high scavenging activity. Especially, the AT-L measured the highest ABTS radical scavenging activity, which is higher than ascorbic acid. The types of human cancer cells for evaluating the anticancer activity were colorectal cancer (SW480), prostate cancer (PC-3), breast cancer (MCF-7), pancreatic cancer (AsPC-1), lung cancer (A549) and liver cancer (HepG2). Human cancer cell viability was measured using MTT assay. Treatment of the AT-L decreased the cell viability and induced apoptosis in SW480 cells. These results suggest that extracts of the AT-L can be used as supplementary material for developing the natural antioxidant and anticancer drug for human cancer cells.
        692.
        2020.06 KCI 등재 서비스 종료(열람 제한)
        This study explores the frequency distribution of the verb seem together with its three alternating complement structures: to-infinitive, that-clause, and adjectival/nominal complements. Based on an analysis of sample data selected from COCA, we investigate the conditions that may influence the choice among these argument structures. Our analysis has shown the following results: First, of the three complement structures, the that-clause complement was rarely used, a pattern consistent with the findings of previous studies. Second, discourse pragmatic factors such as information status and topichood of the subject, and judgement/evaluative semantics of complements were shown to be involved in the selection of the argument structure. Third, the preference for simpler structures evidenced in the usage data suggests the economy principle as a possible force behind the argument selection. The preliminary findings of this study should be complemented by future research with bigger sample data.
        693.
        2020.04 KCI 등재 서비스 종료(열람 제한)
        Mankind has been using ships for more than 5,000 years and has developed a range of related technologies. However, despite such a long history, compared to aircraft with a history of approximately one century, the pace of progress has been markedly slow. Even though technological progress of ships or the installation of various navigation equipment have been achieved, seaborne collisions have occurred quite frequently. This study analyzed the TCAS( Traffic Collision Avoidance System) that has contributed to the prevention of collisions with other transport methods including aircraft to suggest a collision avoidance system that can be deployed for ships. To apply the technologies applied to aircraft that move in 3D to ships that move in 2D, the difference in the operational environment between the two modes was analyzed to identify elements that need to be applied to ships. The suggested display of data on the collision prevention system is one that manipulates the augmented reality display device used in automobiles that over the past few years has undergone rapid development. Based on the presentation of technological elements that need to be considered when adopting the SCAS or the Seaborne Collision Avoidance System as suggested in this study, the authors hope to contribute to the prevention of collisions.
        694.
        2020.04 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The study aims to investigate the relationship between hedging with derivatives and subsequent firm-level stock price crash risk. Our sample consists of KOSPI- and KOSDAQ-listed companies from 2004 to 2014. The total firm-year observation is 4,886. We find that hedging with derivatives is related to greater possibilities of crash risk. The results suggest that the complexity of economic and financial reporting for derivatives may aggravate the company's information opacity, ultimately increasing the crash risk. We contribute to the growing body of literature on hedging with derivatives. Academics and practitioners have debated on whether or not hedging enhances transparency or rather makes the information environment more opaque. Theoretical research on the role of corporate hedging on information environment shows that hedging enhances earnings informativeness. Meanwhile, pieces of anecdotal and empirical evidence show that the economic and financial reporting complexity of derivatives can harm information transparency. Our results shed light on the question of whether and how hedging with derivatives affects information environment by examining the relationship between hedging with derivatives and crash risk. Furthermore, our findings provide useful insights for policymakers and practitioners. Specifically, our results raise a need for a more transparent disclosure on corporate hedging activities with derivatives.
        695.
        2020.04 KCI 등재 서비스 종료(열람 제한)
        본 연구에서는 예비교사를 대상으로 이루어지는 뇌관련 교육의 현황을 확인하고 이러한 교육과 뇌가소성 지식 및 믿음 간 관계를 확인하고자 하였다. 이를 위해 955명(초등 349명, 중등 606명)의 예비교사가 뇌 관련 경험에 대해 응답하였으며 이들 중 514명(초등 266명, 중등 248명)은 추가적으로 뇌가소성 지식과 믿음 수준에 대해 응답하였다. 연구 결과 30%(955명 중 288명)의 예비교사들이 뇌관련 교육 경험을 가지고 있었다. 뇌가소성 지식 4문항 중 한 문항("학습은 신경연결망의 변화와 관련이 있다")이 초등 예비교사와 전체에서 뇌관련 교육 경험이 있을 때 더 높은 정답률을 보이는 것으로 나타났다. 뇌가소성에 대한 믿음은 뇌지식이 교수에 도움이 된다고 믿는 정도와 중요하다고 생각하는 정도와 정적 상관을 보였으며 이러한 관계는 초등 및 중등 예비교사에서 모두 나타났다. 본 연구의 결과는 현재 이루어지고 있는 뇌관련 교육 경험이 예비교사들의 뇌가소성 지식 및 믿음과 낮은 연관을 가짐을 보여준다. 예비교사를 대상으로 한 뇌가소성 지식과 믿음을 높일 수 있는 프로그램이 개발되어야 할 것이다.
        696.
        2020.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        This study designs and analyzes satellite formation flying concepts for the Small scale magNetospheric and Ionospheric Plasma Experiments (SNIPE) mission, that will observe the near-Earth space environment using four nanosats. To meet the requirements to achieve the scientific objectives of the SNIPE mission, three formation flying concepts are analyzed: a crossshape formation, a square-shape formation, and a cross-track formation. Of the three formation flying scenarios, the crosstrack formation scenario is selected as the final scenario for the SNIPE mission. The result of this study suggests a relative orbit control scenario for formation maintenance and reconfiguration, and the initial relative orbits of the four nanosats meeting the formation requirements and thrust limitations of the SNIPE mission. The formation flying scenario is validated by calculating the accumulated total thrust required for the four nanosats. If the cross-track formation scenario presented in this study is applied to the SNIPE mission, it is expected that the mission will be successfully accomplished.
        697.
        2019.12 KCI 등재 서비스 종료(열람 제한)
        Oxidative DNA damage negatively affects humans and the research is currently ongoing to find ways to reduce oxidative stress. Oxidative stress has been identified as a key factor in triggering various diseases. Thus, its alleviation is important for human health. Broussonetia kazinoki (B. kazinoki) has been used in traditional Korean medicine as a dermatological therapy to treat burns, pruritus, and acne. B. kazinoki is generally segregated into peeled root (PR), root bark (RB), peeled stem (PS), and stem bark (SB). To assess these components for their antioxidant activity and protection against DNA damage, their ethyl acetate fractions were examined by 1,1-diphenyl-2-picryl hydrazyl (DPPH) and 2,2'-Azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS) radical scavenging assay. As a result of confirming the expression of factors involved in attenuating DNA damage, the protective effect of SB on oxidative stress suppressed the expression of p-p53 and γ-H2AX. Additionally, the levels of p53 and H2AX mRNA were significantly downregulated. In conclusion, these results indicated that the SB component of B. kazinoki had the potential to be used as an effective natural antioxidant compared to the other parts of the plant.
        698.
        2019.08 KCI 등재 서비스 종료(열람 제한)
        The pathological condition of excessive melanogenesis causing freckles, melasma, senile lentigo, pigmented acne scars, and cancer has a critical impact on the wellness of individuals. The mechanism of melanogenesis is related to the expression of melanogenic enzymes. Here, we evaluated the inhibitory effect of pine cone (Pinus densiflora) extracts on melanogenesis. P. densiflora, the Korean Red Pine, is the predominant tree species in the cool, temperate forests of northeast Asia, occurring in pure stands across Korea, Japan, and parts of northern China and Russia. P. densiflora leaves, pollen, and bark have been widely used for traditional medicine, or edible purposes. However, pine cones are rarely used as natural raw materials, although they contain many bioactive phytochemicals. The pine cone ethyl acetate fraction (PEF) showed no toxicity to B16F10 cells at a concentration of less than 100 ㎍/mL. PEF inhibited the expression of microphthalmiaassociated transcription factor (MITF), tyrosinase and tyrosinase-related factors in B16F10 cells treated with 3-Isobutyl- 1-methylxanthine (IBMX). These results suggest that pine cones can be used as an effective natural melanogenesis inhibitory agent.
        699.
        2019.08 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        This study examines the color image of uniform of airline cabin crew according to the demographic characteristics of the customer and demonstrates how it affects the cognitive image of airlines. Adjective adjectives were derived for uniform color images of all eight airlines in Korea and analyzed the image of airline brand color. Based on the analysis of color images, the difference in perception according to the demographic characteristics of passengers was analyzed. When the colors of airline uniforms are mainly blue, sky blue, white and ivory, they have a lot of trust, neat and elegant images. Uniforms with primary colors such as red, orange and green beans are found to have a lot of cheerful, developmental and enterprising images. In addition, the empirical analysis of the impact of the customer's cognitive perception and favoritism on the uniform color image of the airline crew showed that the more positive the airline's positive perception of the uniform color image, the more positive the cognitive image is. In other words, the empirical analysis revealed that the airline's uniform color image, its cognitive image of the airline, and its popularity have significant positive relationships.
        700.
        2019.06 KCI 등재 서비스 종료(열람 제한)
        This study explores the distribution of the multi-functional V-ing construction in Korean college freshmen’s written English, focusing on its use across different proficiency levels and text types. A small corpus (75,000 words) consisting of narrative and argumentative essays was analyzed, producing the following results: 1) The overall frequency of the V-ing construction exhibited a relation, though non-linear, with L2 proficiency. 2) The V-ing construction was more common as the gerund than the participle, a pattern consistent with what was observed in previous NS studies. 3) In argumentative essays, gerunds as sentential subjects were as common as the prepositional object function in contrast to the overwhelming number of prepositional objects in NS data. 4) The adverbial participle clause emerged ahead of the nominal modifier, and the subordinate participle clauses tended to precede the matrix clauses in the narrative essays and in the argumentative essays of the lower level learners. Influence of the essay prompts, learners’ insufficient knowledge of the lexico-discourse features of the gerund and the participle clauses were conjectured to have attributed to the pattern incongruent with that of NS usage. Pedagogical implications are suggested to enhance L2 learners’ knowledge of the target construction.