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        검색결과 1,031

        801.
        2003.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Pure WC powders which does not include a binder phase were consolidated by spark plasma sintering (SPS) process at 1600~185 for 0~30 min under 50 MPa. Microstructure alid mechanical properties of binderless WC prepared by SPS were investigated. With increasing sintering temperature, sintered density and Vickers hardness of binderless WC increased. The fracture toughness of binderless WC was 7~15 MPa depending on the sintered density and decreased with increasing the Vickers hardness. It is found that the binderless WC prepared by SPS at 175 for 10 min under 50 MPa showed nearly full densification with fine-grained structure and revealed excellent mechanical properties of high hardness (~HV 2400) and considerably high fracture toughness (~7 MPa ).
        4,000원
        807.
        2002.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Aligned multi-wall carbon nanotubes (MWNTs) were synthesized through the catalytic decomposition of hydrocarbons in a quartz tube reactor. In this study, we investigated the influence of reaction parameters such as gas flow rate, ferrocene-xylene ratio and partial pressure, and reaction time on the yield and structure of vertically aligned carbon nanotubes produced by the floating catalyst method. The MWNTs produced had diameters in the range of 20~l00 nm, length around 100μm and bulk density about 0.51g/cm3 at a pressure of l0000 psi. It was possible to produce MWNTs with much faster growth rate of 12μm/min than that reported previously by the increase of ferrocene-xylene partial pressure.
        4,000원
        809.
        1999.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국내 미기록종인 배나무를 가해하는 배잎녹응애(Phyllocoptes pyrivagrans Kadono, 1985)를 발견하였으므로 이에 기재 보고한다.
        3,000원
        810.
        1990.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        4,000원
        811.
        2021.12 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The auroral observation has been started at Jang Bogo Station (JBS), Antarctica by using a visible All-sky camera (v-ASC) in 2018 to routinely monitor the aurora in association with the simultaneous observations of the ionosphere, thermosphere and magnetosphere at the station. In this article, the auroral observations are introduced with the analysis procedure to recognize the aurora from the v-ASC image data and to compute the auroral occurrences and the initial results on their spatial and temporal distributions are presented. The auroral occurrences are mostly confined to the northern horizon in the evening sector and extend to the zenith from the northwest to cover almost the entire sky disk over JBS at around 08 MLT (magnetic local time; 03 LT) and then retract to the northeast in the morning sector. At near the magnetic local noon, the occurrences are horizontally distributed in the northern sky disk, which shows the auroral occurrences in the cusp region. The results of the auroral occurrences indicate that JBS is located most of the time in the polar cap near the poleward boundary of the auroral oval in the nightside and approaches closer to the oval in the morning sector. At around 08 MLT (03 LT), JBS is located within the auroral oval and then moves away from it, finally being located in the cusp region at the magnetic local noon, which indicates that the location of JBS turns out to be ideal to investigate the variabilities of the poleward boundary of the auroral oval from long-term observations of the auroral occurrences. The future plan for the ground auroral observations near JBS is presented.
        812.
        2019.12 KCI 등재 서비스 종료(열람 제한)
        Avocado, superfood, contains a variety of essential nutrients and phytochemicals. The purpose of this study was to explore whether avocado could modulate skin inflammation in vivo. We elucidated the pharmacological effects of avocado on compound 48/80- or histamine-induced scratching behaviors and 2, 4-dinitrochlorobenzene (DNCB)-induced atopic dermatitis (AD)-like skin lesions in mice. Additionally, we investigated the anti-inflammatory activity of avocado and its underlying mechanism including its effect on the expression levels of inflammatory-related genes and nuclear factor -κB (NF-κB) in DNCB-induced AD-like skin lesions. The findings of this study demonstrate that avocado attenuated AD clinical symptoms including itching, eczematous, erythema and dryness and histamine levels in mice. Moreover, avocado suppressed both inflammatory cytokines expression as well as NF-κB and caspase-1 activation in AD-like skin lesions in mice. Taken together, these results demonstrate that avocado may be a potential candidate for treating skin inflammatory diseases like AD.
        813.
        2018.12 KCI 등재 서비스 종료(열람 제한)
        Aralia cordata (A. cordata), which belongs to Araliaceae, is a perennial herb widely distributed in East Asia. We evaluated the anti-inflammatory effect of stems (AC-S), roots (AC-R) and leaves (AC-L) extracted with 100% methanol of A. cordata and elucidated the potential signaling pathway in LPS-stimulated RAW264.7 cells. The AC-L showed a strong anti-inflammatory activity through inhibition of NO production. AC-L dose-dependently inhibited NO production by suppressing iNOS, COX-2 and IL-β expression in LPS-stimulated RAW264.7 cells. AC-L inhibited the degradation and phosphorylation of IκB-α, which donated to the inhibition of p65 nuclear accumulation and NF-κB activation. Furthermore, AC-L suppressed the phosphorylation of ERK1/2 and p38. These results suggested that AC-L may utilize anti-inflammatory activity by blocking NF-κB and MAPK signaling pathway and indicated that the AC-L can be used as a natural anti-inflammatory drugs.
        814.
        2018.09 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        본 연구는 완주에서 재배된 세계 주요 11개 적포도 품종으로 제조된 적포도주의 향기 성분을 headspace-solid phase microextraction 분석법으로 확인하였다. 향기성분은 총 75종이 확인되었다. 아로마화합물은 그들의 OAV 값에 의해 5 그룹으로 나뉘었다. 알콜, 알데하이드, 에스테르, C6 화합물이 11개 적포도주의 주요한 향기성분이었다. Isoamy alcohol 알콜과 phenylethyl 알콜은 11개 포도주에서 공통적으로 꽃향기, 달콤한 향을 나타내는데 중요한 물질이었다. Octanoic acid, ethyl ester, hexanoic acid ethylester은 모든 레드와인에서 과실향과 꽃향, 달콤한 향을 내는 중요한 성분이었다. 1-Hexanol은 모든 포도주에서 분석되었으나 풀향을 나타내는 향으로 나타났다. Chanceller, Malbec, marchel, Nsrsha, Pinot Meunier, Sangiovetto 포도주의 주요 향기성분은 과실 향인 것으로 나타났으며 Cabernet Franc, Cabernet Sauvignon, Sauvignon Vert 포도주의 주요 향기성분은 풀향인 것으로 조사되었다. 또한, MBA와 Narsha 포도주의 경우 꽃향이 주요 향인 것으로 조사되었다. 본 연구 결과를 바탕으로 적포도주용 품종을 육성할 때 선발기준으로 향기성분 분석을 활용할 수 있을 것으로 판단되었다.
        815.
        2018.08 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Paying close attention to those new to an organization, whether fresh or experienced, whose primary interest is in (re)socialization, the current study intends to (1) further the concept of mentoring from a bilateral relationship to a community and culture fostered by developmental networks, (2) propose an integrated conceptual framework for organizational socialization, and (3) suggest implications for practice and future research. This study reviews, analyzes, and integrates research assets and subsequently re-conceptualizes the aggregate information as valid propositions and a conceptual framework. The findings include (1) 11 propositions regarding the relationships among network characteristics (embeddedness, diversity), developmental functions (career support, psychosocial support, and role modeling), and socialization outcomes (learning and attitudinal outcomes); and (2) an integrated conceptual framework that depicts a comprehensive mechanism through which developmental networks conduce to organizational socialization of newcomers. Implications are that developmental networking must be an individual’s fundamental competency and an essential part of organizational onboarding processes, and imperative for both members’ career development and innovative organizational culture. By integrating research assets on the developmental phenomenon into conceptualizations, this study furthers the concept of mentoring to organizational culture and stimulates a substantive discourse for theory-building towards organizational socialization from the developmental network perspective.
        816.
        2018.06 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Dendropanax morbifera Leveille (Araliaceae) is an endemic species growing in the south-western part of South Korea that has been used in folk medicine and health functional food. In this study, we investigated an extract of quercetin in Jeju D. morbifera by varying different parts (fruit, sprouts, leaves, sprigs, and branches), harvest times, and extraction solvents. In addition, we aimed to establish a simple and reliable HPLC/UV analytical method to determination of quercetin for the quality control and base line data of the Jeju D. morbifera extract as a health functional food ingredient. The analytical specificity was determined with retention time and photo diode array (PDA) spectrum by analyzing quercetin using HPLC and comparing the results to those of extracts. This analytical method for quercetin was validated for its limit of detection (LOD), limit of quantitation (LOQ), precision, and accuracy. A high linearity in the standard calibration curve was obtained, with a coefficient of determination (R2) of 0.9996. Also, the LOD and LOQ values were found to be 0.28 μg/mL and 0.85 μg/mL, respectively, and the recoveries of quantified compounds ranged from 97.91% to 104.10%. Furthermore, the relative standard deviation (RSD) values of data from the intra- and inter-day precision analyses were less than 1.36% and 3.65%, respectively. As a result, the highest quercetin content among the extracts of Jeju D. morbifera leaves was found to be 20.14 mg/g, which was extracted at harvest in May (cultivation period 10 years) with 60% EtOH. All in all, we believe that the results obtained would be helpful in the development of nutraceutics and natural medicines and for the quality control of D. morbifera.
        817.
        2018.06 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        This study was conducted to compare the volatile flavor compounds of Artemisia annua L. after extraction by simultaneous steam distillation extraction (SDE) and solid-phase micro extraction (SPME) followed by gas chromatography-mass spectrometry (GC-MS) analysis. Via SDE and SPME processes, 79 (1,254.00 mg/kg) and 39 (488.74 mg/kg) compounds were identified respectively. The compounds extracted by SDE included 27 alcohols, 13 aldehydes, 22 hydrocarbons, 3 esters, 12 ketones, 1 oxide and 1 N-containing compound, on the other hand, using the SPME method, 7 alcohols, 5 aldehydes, 1 ester, 18 hydrocarbons, 7 ketones, and 1 oxide were extracted. The major volatile flavor compounds of Artemisia annua L. isolated by the two methods were caryophyllene oxide, -caryophyllene, camphor, -selinene, -muurolene, 1,8-cineol, (E)-pinocarveol and pinocarvone. β β γ The sesquiterpene named caryophyllene oxide was the most abundant volatile flavor compound with relative contents of 234.16 mg/kg and 195.44 mg/kg obtained by the SDE and SPME methods, respectively. Among the identified volatiles, sabinene, β-pinene, α-terpinene, γ-terpinene, yomogi alcohol, myrtenol, (Z)-nerolidol, p-cymen-8-ol and eugenol were detected by the SDE method only while (E)-anethole and α-cubebene were detected by the SPME method only. This study confirmed that the composition and contents of the volatile flavor compounds vary between different extraction methods. More volatile flavor compounds were identified using the SDE method than the SPME method.
        818.
        2018.04 KCI 등재 서비스 종료(열람 제한)
        흡연 유무의 남성을 대상으로 뇌 회백질의 손상 유무를 파악 할 수 있는 확산텐서영상을 검사하여 영상을 획득 한 후 Tract-Based Spatial Statics(TBSS)방법으로 뇌 회백질 부위의 기저핵 신경섬유로의 비등방도 FA(fractional anisotropy)값을 측정 분석한 결과 모든 영역에서 흡연자가 비흡연자보다 비등방성 측정값이 낮게 관찰되었으며 FA값은 통계적으로 유의하였다. 본 연구의 측정한 FA결과 값으로 추측하자면 즉, 흡연이 뇌 회백질 기저핵의 모든 해부학적 미세 구조성 변화에 크게 영향을 미치며 신경 섬유로를 손상시키고 이와 관련된 기능적 이상에 영향을 준다고 할 수 있다.
        819.
        2018.04 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        Fermented halla gold kiwifruit (FHK) was prepared with Lactobacillus plantarum CK10, a bacterium derived from kimchi. We investigated the quality characteristics and antioxidative activity of madeleine added with FHK. The madeleine dough was prepared by mixing flour, sugar, baking powder, and then followed by adding salt, rum, different amount of the FHK (0, 1, and 3%) and butter. The total titratable acidity of madeleine increased significantly with the amounts of added FHK (p<0.05), while the pH value and total soluble solids showed the reverse trend. The color of madeleine became substantially redder with increasing amounts of FHK (p<0.05), and it appeared darker and less yellow at the same time. The total polyphenol contents of madeleines increased significantly with increasing amounts of FHK (p<0.05), but there was little difference in the total flavonoid content. When the antioxidant activities were measured in terms of 2,2-diphenyl-1-picrylhydrazyl (DPPH)- and 2,2’-azino-bis-3-ethylbenzothiazoline- 6-sulfonic acid-diammonium salt (ABTS)- radical scavenging, both measured activities of madeleines increased dramatically with added FHK in a dose-dependent manner. Our results suggested that the acidity, color, polyphenol content, and antioxidant activities of madeleines can be improved by adding the fermented gold kiwifruit.
        820.
        2018.04 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        The study compared the juice and wine odorants of the Cheongsoo grape cultivar with those of Chardonnay and Reisling wines. The volatile compounds of the three grape varieties were analyzed using headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry. The most common volatile compounds in the juices from the three cultivars were terpenes, C13-norisoprenoids, etones, alcohols, and aldehydes. Terpenes were established as the most abundant group of volatiles in Cheongsoo grape juice, where as aldehydes predominated in Chardonnay and Riesling juices. Forty-two volatile compounds (acids, alcohols, esters, and others) were detected in the three white wines. The concentration of esters was about four times higher in Cheongsoo wine than in Chardonnay and Riesling wines. Five esters found in the Cheongsoo wine, namely, isoamyl acetate, ethyl butanoate, ethyl hexanoate, ethyl octanoate, and ethyl decanoate, exhibited high odor activity values (OAV) of >1. Furthermore, only Cheongsoo wine had a high OAV for isoamyl acetate odorant, which is associated with banana and sweet aromas. Therefore, the abundant and varied esters are believed to be key volatile fruity/sweet odorants in Cheongsoo wine.