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        검색결과 16

        1.
        2023.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        많은 생태학자는 식물군락 및 군집이 환경요인과 상호작용하여 나타내는 변화 과정을 이해하기 위해 노력하고 있다. 산림식생 보다 역동적인 하천 주변에 형성되는 식물군집은 하천의 교란동태에 밀접하게 연관되어 있다. 비술나무는 한반도 중부이북에 분포하는 하천의 가장자리에 군집을 형성한다. 우리는 남한강의 상류 지역에서 비술나무 군집이 정착하고 발달하는 과정을 이해하고자 하였다. 하천의 수면으로부터 군집의 중앙지점의 높이는 수령등급이 증가함에 따라 높아졌다. 반면에 비술나무의 높이는 수령등급이 증가함에 따라 증가하였다가 감소하는 경향을 나타내었다. 풍부도 (Richness(S)), 균등도(Evenness(J')), 다양도(Diversity(H') 및 최대다양도(Maximum diversity(H'max))도 수령등급이 증가함에 따라 증가하였다가 감소하는 경향을 나타내었다. 반면에 개체 당 줄기의 수 및 밀도(Density(D))는 수령등급이 증가함에 따라 감소하였다. 비술나무의 유묘는 수령등급 중간 단계이상의 군집 내에는 재정착에 성공하지 못했다. 유묘의 재정착은 하천에서 주기적으로 발생하는 범람에 의해 생성된 공간에 정착하였다. 재정착 이후 비술나무 군집은 하나의 유기체와 같이 성장하였다. 반면에 비술나무 군집을 구성하는 식물 종은 군집이 발달함에 따라 풍부도 (Richness(S)), 다양도(Diversity(H')는 증가하였다가 감소하는 과정을 나타내었다. 즉 구성종의 변화는 각각의 종과 군집의 환경변화와 연관된다고 판단되었다. 비술나무 군집의 재생을 위해서는 종자에 의한 유묘의 재정착이 가능한 공간이 공급되어야 한다. 본 조사가 이루어진 남한강의 중상류 지역에서는 비술나무의 재정착에 필요한 공간이 소멸되어 새롭게 생성되는 군집은 매우 드물었다. 따라서 남한강 상류 지역에서 비술나무 군집의 유지를 위해서는 유묘의 재정착 에 필요한 적절한 공간의 확보가 필요함을 제안한다.
        5,800원
        2.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        한국산 둥글장수풍뎅이(Pentodon quadridens bidentulus)의 3령 유충과 번데기의 형태를 처음 기술한다. 서식지와 실험실 사육에서 둥글장수 풍뎅이의 생태, 분포, 생활사 또한 제공한다.
        4,000원
        3.
        2019.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        본 논문은 공학적방벽시스템의 THM 복합거동을 분석하기 위해 구축한 In-DEBS를 실제 운영하며 취득한 운영 초기 100일간의 현장데이터에 대해 살펴보고자 한다. 콘크리트로 플러깅을 한 In-DEBS 상부에서는 콘크리트가 양생하는 동안 열을 발생하게 되어 In-DEBS의 완충재 및 근계암반에 영향을 미치게 된다. 콘크리트 플러깅에서 멀어질수록 완충재 및 근계암반의 온도는 점점 감소하게 되는데, 이러한 현상을 이용하여 센서 및 계측 시스템을 검증하였다. 처분용기를 모사한 히터는 온도제어를 통해 용기 표면 온도를 100℃로 유지할 수 있도록 설정하였으며, 시스템의 안전을 위해 일주일 동안 서서히 목표온도까지 올렸다. 히터 가동 직후 완충재의 온도는 약 4일 만에 정상상태에 도달하였으며, 상대습도는 증가하였다가 일정시간이 지난 뒤에 서서히 감소하는 것을 관찰할 수 있었다. 또한 지하수 포화에 따른 팽윤에 의해 완충재의 압력이 증가하는 것을 볼 수 있었다. 근계암반에서는 히터 가동 후 온도가 계속 증가하며, 암반의 변위도 계속 증가하는 것을 관찰할 수 있었다.
        4,800원
        4.
        2019.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        본 논문은 고준위폐기물 처분시스템에서 공학적방벽의 열-수리-역학적(Thermal-hydraulic-mechanical) 복합거동 실증을 위 In-DEBS (In-situ Demonstration of Engineered Barrier System) 를 개발하여 구축하는 과정에 대해 설명한다. 공학적방벽은 크게 처분용기, 완충재 그리고 근계암반으로 이루어져 있는데, In-DEBS는 완충재 및 근계암반을 대상으로 지하수 유입 및 처분용기의 발열에 의한 THM 복합거동을 분석할 수 있도록 설계되어 있다. In-DEBS 현장시험은 A-KRS의 1/2.3 규모로 설계되어 있기 때문에 처분공의 지름이 약 860 mm로 작게 굴착하였다. 따라서, 처분공 안에서 센서와 히터를 삽입하면서 완충재 블록을 조립하는 것은 힘들기 때문에 완충재 블록 일체형 설치 틀(OBPA)를 개발하여 외부에서 모두 조립하였다. 완충재블록, 센서 및 히터가 조립 완료된 일체형 설치 틀은 총 무게가 약 3톤으로 매우 무겁기 때문에, 처분공에 정확히 삽입하기 위해서는 특별한 운송기구가 필요하다. 본 연구에서는 레일을 이용하여 5톤 이상의 무게를 들어서 정확한 위치에 정치 시킬 수 있는 In-DEBS 전용 크레인을 개발하여 조립완료된 완충재 블록을 삽입하였다. 근계암반의 THM 복합거동을 분석하기 위해 In-DEBS 주위로 4개의 시험공을 굴착하여 총 40개의 온도 센서와 5개의 간극수압계를 설치하였다. 또한 근계암반의 변위를 측정하기 위해 원거리에서 두 개의 경사공을 굴착하여 총 10개의 변위 센서를 삽입하였다. In-DEBS에는 공학적방벽시스템에 온도, 상대습도, 압력, 그리고 변위 센서 등 총 185개의 센서가 설치되어 있으며, 이 센서들은 모두 다채널 동시 측정이 가능한 계측시스템에 연결되어 실시간으로 현장데이터를 저장하게 된다.
        5,400원
        6.
        2015.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Yongneup wetland protected area, the only high moor in Korea, is a core area to conserve biodiversity. Even though the Yongneup wetland protected area is relatively small, various plant species are distributed in the Yongneup wetland protected area because it includes various habitats showing different environmental gradients. Vascular plants distributed in the Yongneup wetland protected area were identified as a total of 376 taxa that is composed of 73 families, 217 genera, 322 species, 3 subspecies, 44 varieties and 7 forms. For endangered plants designated by the Ministry of Environment, 5 species including Trientalis europaea var. arctica, Lilium dauricum, Halenia corniculata, Lychnis wilfordii and Menyanthes trifoliata were found and 34 taxa were confirmed to be distributed only in the mountainous wetland habitats. Regarding naturalized plants, a total of 11 taxa were distributed, but most of them were distributed in the areas where artificial interference has occurred. And in areas inside the wetlands that are relatively well preserved, 2 species of Bidens frondosa and Erigeron annuus were observed. In this study, the occurrence and distribution of Pseudostellaria baekdusanensis M. Kim, which was recently found in Mt. Baekdu and reported as a new species, were identified in the Yongneup wetland protected area. A wetland is a very vulnerable area to drastic environmental changes and damages to its ecosystem could cause the extinction of rare plant species which are distributed only in the wetlands. Therefore, it is mandatory that current status of the Yongneup wetland protected area is evaluated and actions to prevent rapid environmental changes are taken. Fourteen separate investigations were conducted in 2013 and another four in 2014, to evaluate current status of the Yongneup wetland protected area. These investigations have provided us the basic information for future actions of conservation and restoration.
        4,500원
        7.
        2012.03 구독 인증기관 무료, 개인회원 유료
        This study was conducted in order to evaluate the alleviating effects of Phellodendrin cortex water extract (PCWE) on skin aging in hairless mice via observation of morphogical and histological changes. Skin aging was induced by UVB irradiation and application of squalene monohydroperoxide (Sq-OOH) to the back skin of hairless mice for six weeks. And, at the same time, saline (C), jojoba oil (VC), PCWE (E), and 0.01% retinoic acid diluted with polyethylene glycol (PC) were applied topically twice per day, six days per week, for a period of six weeks. Improved wrinkle formation in a pattern of shallow furrows and thin and narrow crests was observed in the retinoic acid and PCWE application groups, compared to the C group. On the morphologic analysis for skin wrinkles, the E group showed lower levels in skin roughness, maximum roughness, average roughness, smoothness depth, and arithmetic average roughness by 13.1, 17.2, 18.4, 15.4, and 16.1%, respectively, compared with the C group, indicating that PCWE inhibited potential formation of wrinkles in the skin. In the C group, structures of lipid lamellae and collagen fibers were broken or deformed with an irregular arrangement. Application of retinoic acid and PCWE protected against the deformity of lipid lamellae and collagen fibers. Elastic fibers in dermis of the C group also showed severe transformation; however, applications of retinoic acid and PCWE resulted in a significant decrease in the number of denatured elastic fibers. Therefore, PCWE could have an alleviating effect on skin aging induced by UVB irradiation and application of Sq-OOH.
        4,300원
        8.
        2011.12 구독 인증기관 무료, 개인회원 유료
        This study was conducted for evaluation of the alleviating effects of Phellodendrin cortex water extract (PCWE) on skin inflammation in hairless mice. Skin inflammation was induced by UVB irradiation and application of squalene monohydroperoxide (Sq-OOH) to the back skin of hairless mice for six weeks. At the same time, saline (C), jojoba oil (VC), PCWE (E), and 0.01% retinoic acid diluted with polyethylene glycol (PC) were applied topically twice per day, six days per week for a period of six weeks. The skin erythema index of the E group was lower than that of the C group. Epidermis and dermis of the C group were remarkably thickened, compared to the PC or E group. In the C group, infiltration of many inflammatory cells, including neutrophils and lymphocytes, was observed in dermis, and a large number of mast cells were observed in dermis and hypodermis; the degree of degranulation was remarkable. However, these phenomena were alleviated in the PC and E2 groups. The E group showed a lower activity in skin xanthine oxidase but a higher activity in skin superoxide dismutase, compared to the C group (P<0.05). The VC, PC, and E groups also showed a high activity of skin catalase by 25.3%, 58%, and 42%, respectively, compared to the C group. Taken together, these results indicate that PCWE could have an alleviating efficacy on skin inflammation induced by UVB irradiation and application of Sq-OOH in hairless mice.
        4,000원
        9.
        2011.10 구독 인증기관·개인회원 무료
        Pigs may be considered as a suitable organ source for its characteristics in xenotransplantation if significant immunological barriers can be overcome. However, xenograft could be rejected by T cells, especially CD8+ cytotoxic T lymphocytes (CTL)-mediated response, because these elements show great cytotoxicity against xenograft by recognizing Swine Leukocyte Antigen (SLA)-I. Human cytomegalovirus (HCMV) encodes unique short (US) 11 gene, which interferes with cellular immune responses by inducing rapid degradation of newly synthesized heavy chains (HC) of MHC class I from endoplasmic reticulum (ER) to the cytosol. In this study we established two US11 clonal cell lines by transfection into minipig fetal fibroblasts and confirmed the integration of US11 gene by PCR and FISH. The reduction of Swine Leukocyte Antigen (SLA)-I which was expressed on the cell surface by US11 was also detected by flow cytometry assay. The level (14.6 % to 21.2%) of SLA-I expression in US11 clonal cell lines was decreased relative to the control. The reconstructed embryos were produced with these clonal cells and transferred to nine surrogate gilts. Ultrasound examination of recipient surrogates on days 35 after embryo transfer confirmed established pregnancies in two recipients. One recipient delivered one piglet with normal birth weight. PCR analysis revealed that transgene vector was integrated in the offspring genome. Transgene-expression analysis and CTL assay are currently underway. The present results show that transgenic pig was produced with US11 cDNA for controlling cell-mediated rejection. This result indicated that grafts of transgenic pigs expressing human cytomegalovirus protein US11 could control the cellular immune response to xenografts, and create a window of opportunity to facilitate xenograft survival. This research was supported by the BioGreen 21 Program (#20110301-061-541- 001-05-00), Rural Development Administration, Republic of Korea.
        10.
        2010.12 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to evaluate the alleviative effects of a nude pack containing black tea water extract (NPBT) on inflammation and skin barrier damage in hairless mice. Skin inflammation and skin barrier damage were induced by UVB irradiation to the backs of hairless mice for five weeks. And, at the same time, saline (C), NPBT (1%: E1, 2%: E2), and 0.01% retinoic acid diluted with polyethylene glycol (PC) were applied topically twice per day, five days per week, for a period of five weeks. The skin erythema indices of the E1 and E2 groups were significantly lower (p<0.05) than those of the C group through one week after the beginning of the experiment. Meanwhile, water contents of the E1 and E2 groups were significantly higher (p<0.05) than those of the C group through two weeks after the beginning of the experiment. Remarkable thickening of epidermis and dermis was observed in the C group, compared with the PC, E1, or E2 groups. In the C group, infiltration of many inflammatory cells, including neutrophils and lymphocytes, was observed in dermis and a large number of mast cells were observed in dermis and hypodermis, and the degree of degranulation was remarkable. However, these phenomena were alleviated in the PC, E1, and E2 groups. Therefore, NPBT could have considerable inhibitory efficacy on inflammation and skin barrier damage induced by UVB irradiation.
        4,000원
        11.
        2009.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The field emitters were fabricated by screen-printing of carbon nanotube paste, and their emission stabilities were evaluated. It was found that the emission stability measured in a sealed device is much higher than that measured in a vacuum chamber in spite of similar pressure. This was because oxygen gas was scarcely remained in the sealed device, while the gas is continuously supplied into the vacuum chamber during the stability measurement. It was found that the plasma treatment etched the protruded CNTs, resulting in the uniform height of CNT tips. As a result, the stability was increased remarkably. It was also found that the stability of CNT paste emitter was improved by electrical aging and that the optimum condition for the aging was varied with the size of emitter.
        4,000원
        13.
        2002.01 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The land-cover of two regions of South and North Korea included in one Landsat TM scene was investigated by comparing different seasons and different band data over the multiple land-cover types. The relationships between the intensities of two bands in the 2-D plot are mainly linear in band2 versus band1 and band3 versus band1, polygonal sporadic in band5 versus band1 and band7 versus band1, and almost tri-polarized in band4 versus band3. The 2-D plot of band4/band3 shows the best capability to discriminate different main land-cover such as water, vegetation and dry soil. Some discriminations are not clear between city and dry field, or mountain and plain field in the scene of September. The digital number data of band4 from vegetated zones show stronger reflectance in September rather than April, while other band values tend to be lager in April than in September over each land-cover. NDVI presents high value in both regions in September. However the image of Wonsan area in April suggests weak vigor of vegetation in comparison with Cholwon area. Band ratios are very effective in eliminating the influence of the complex topography. The proper pairing of the band ratio improved the discrimination capability of the land-cover; band5/band2 for dry soil, band4/band3 for vegetation and band1/band7 for the water. The RGB combination of the three band ratio pairs showed the best results in the discrimination of the land-cover of Wonsan, Cholwon and even the Demilitarized Zone.
        4,600원
        14.
        1995.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The HII region S140 and the associated molecular cloud L1204 have been observed with 10 molecular transitions, CO (1-0), 13CO (1-0), C18O (1-0), CS (2-1), HCO+ (1-0), HCN (1-0), SO (22-11), SO2(220-313), OCS (8-7), and HNCO (404-303) with ~ 50" angular resolutions. More than 7,000 spectra were obtained in total. The morphology of this region shows a massive fragment (the S140 core) and the extended envelope to the northeast. Several gas condensations have been identified in the envelope, having masses of ~103M⊙ and gas number densities of ≾104cm-3 to 3×105cm-3 in their cores. The column densities of the observed molecular species toward the S140 core appear to be the typical warm clouds' abundances. It seems to be that the S140 core and L1204 have been swept up by an expanding shell called the Cepheus bubble. The large value of LIR(embedded stars)/Mcloud ~5 L⊙/M⊙ of the S140 core may suggest that the star formation has been stimulated by the HII region, but the shock velocity and the pressure of the region seem to give a hint of the spontaneous star formation by the self gravity.
        4,000원
        15.
        2020.04 서비스 종료(열람 제한)
        Sport activities of the local residents are admitted as a positive and awarding welfare. This study reviews the current status of and the way to activate life sport program on the policy level that would bring a number of effects. By reviewing related-literature review, this study presents theoretical and practical foundation regarding on the necessity for the local social welfare, organization operation, facilities, participation, leadership, and program management. Finally, the authors suggest policies for life sport development on local level below. First, in order to the function of sport for all in social welfare system, it is needed to pursue institutional changes to secure diversity in the age group which participates in sports for all. Second, connectivity in public sports facilities should be fortified. The government should develop sports program in conjunction with public sports facilities built for the interest of community members. Third, club advisors should be educated with well organized-manual and reeducated to rebuild their capacity to develop the programs and manage them if necessary. In the similar view, the policy which can check the advisor’s field experience and ability should be prepared. Fourth, for economic sustainability, a profit generating project developing a target marketing strategy is required.
        16.
        2014.03 KCI 등재 SCOPUS 서비스 종료(열람 제한)
        This paper describes an experimental approach to evaluate the effective doses of space radiations at high-altitude by combining the measured data from the Liulin-6K spectrometer loaded onto the air-borne RC-800 cockpit and the calculated data from CARI-6M code developed by FAA. In this paper, 15 exposed dose experiments for the flight missions at a highaltitude above 10 km and 3 experiments at a normal altitude below 4 km were executed over the Korean Peninsula in 2012. The results from the high-altitude flight measurements show a dramatic change in the exposed doses as the altitude increases The effective dose levels (an average of 15.27 μSv) of aircrew at the high-altitude are an order of magnitude larger than those (an average of 0.30 μSv) of the normal altitude flight. The comparison was made between the measure dose levels and the calculated dose levels and those were similar each other. It indicates that the annual dose levels of the aircrew boarding RC- 800 could be above 1 mSv. These results suggest that a proper procedure to manage the exposed dose of aircrew is required for ROK Air Force.