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        검색결과 19

        3.
        2015.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study suggested comprehensive structural characterization methods for the commercial blue light emitting diodes(LEDs). By using the Z-contrast intensity profile of Cs-corrected high-angle annular dark field scanning transmission electron microscope(HAADF-STEM) images from a commercial lateral GaN-based blue light emitting diode, we obtained important structural information on the epilayer structure of the LED, which would have beendifficult to obtain by conventional analysis. This method was simple but very powerful to obtain structural and chemical information on epi-structures in a nanometer-scale resolution. One of the examples was that we could determine whether the barrier in the multi-quantum well(MQW) was GaN or InGaN. Plan-view TEM observations were performed from the commercial blue LED to characterize the threading dislocations(TDs) and the related V-pit defects. Each TD observed in the region with the total LED epilayer structure including the MQW showed V-pit defects for almost of TDs independent of the TD types: edge-, screw-, mixed TDs. The total TD density from the region with the total LED epilayer structure including the MQW was about 3.6 × 108 cm−2 with a relative ratio of Edge- : Screw- :Mixed-TD portion as 80%: 7%: 13%. However, in the mesa etched region without the MQW total TD density was about 2.5 × 108 cm−2 with a relative ratio of Edge- : Screw- :Mixed TD portion of 86%: 5%: 9 %. The higher TD density in the total LED epilayer structure implied new generation of TDs mostly from the MQW region.
        4,000원
        4.
        2013.04 구독 인증기관·개인회원 무료
        미국선녀벌레는 노린재목 선녀벌레과(Flatidae)의 외래유입 흡즙성 해충으로 2012년 31개 시군구로 분포가 도로변을 중심으로 확산 추세에 있다. 미국선녀벌레 는 아카시나무 등에서 알로 월동을 하고 년 1회 발생을 하는데 5-6월에 부화된 약충 이 10월까지 기주식물을 흡즙하여 직접 피해를 주며 왁스물질과 감로를 분비하기 때문에 외관상 혐오감과 잎과 과일에 그을음병을 유발하여 상품가치를 저하시켜 농가에 피해를 준다. 우리나라에서는 단감, 포도, 배, 사과 등 과수작물과 콩, 옥수 수 등 식량작물에 피해가 우려되고 있다. 따라서 국립농업과학원에서는 외래 돌발 해충인 미국선녀벌레에 대한 피해를 최소화하기 위해 기초적 생리·생태적 정보를 바탕으로 한 친환경해충관리기술을 개발하고 있다. 본 연구에서는 해부현미경과 주사전자현미경을 이용하여 미국선녀벌레 약충과 성충의 구기와 구침, 더듬이의 감각기 분포와 형태를 관찰하고 다른 흡즙성 해충과 비교하였다. 구기의 미세구 조 정보를 바탕으로 미국선녀벌레의 섭식행동에 대한 연구가 앞으로 진행될 예 정이다.
        5.
        2011.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Glutamate-induced oxidative injury contributes to neuronal degeneration in many central nervous system (CNS) diseases, such as Parkinson’s disease, Alzheimer’s disease, epilepsy and ischemia. Inducible heme oxygenase (HO)-1 acts against oxidants that are thought to play a role in the pathogenesis of these diseases. The EtOH extracts of Viola mandshurica (NNMBS274), Viola patrinii (NNMBS275) and Viola papilionacea Pursh (NNMBS276), origin plants of Violae Herba, showed the potent neuroprotective effects on glutamate-induced neurotoxicity. Among them, NNMBS275, the extract of V. patrinii possessed the protective effects against glutamate toxicity by inducing the expression of heme oxygenase (HO)-1 in the mouse hippocampal HT22 cells. These results suggest that extracts of V. patrinii could be the effective candidates for the treatment of ROS-related neurological diseases. Furthermore, it is suggested that the protective effects of V. patrinii extract due to inducing the expression of HO-1 asAs the exfoliated keratinocytes (EKs) in oral mucosa are aging and degenerating cells, of which cytoplasms are almost replaced by cross-linked keratin materials. Consequently, the EKs become apoptotic with nuclear lysis. A question is arisen what is the biological role of these EKs in oral cavity? Are they simply degrading as aging keratinocytes or do they have some essential function still remained in the exfoliated status? The buccal smear samples from ten healthy adult subjects were observed under scanning electron microscope. On the outer surface of the EKs the features of bacterial adhesion were explored. The microorganisms attached on the surface of EKs were much deformed, shrunken and teared. Only a few microorganisms were found on the EK surface, aggregated focally. The attached microorganisms were gradually fused on the cell membrane of EKs, and subsequently endocytosed. Resultantly, many round endocytotic concave cavities similar size to the cocci were remained on the surface of EKs similar to the sequels of caveolae endocytosis. These data indicate that the degenerating EKs can actively engulf microorganisms attached on their cell surface via the processes of caveolae endocytosis. Therefore, it is presumed that the oral EKs still play a role for endocytotic scavenging of oral microorganisms using the denatured cell bodies themselves, which become highly adherent to oral microorganisms and still function for caveolae endocytosis in mixed saliva environment. an antioxidant/cytoprotective target
        4,000원
        6.
        2007.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The external ultrastructural morphology and distribution of antennal sensilla and hair-pencils of Palpita indica (Saunder) were examined by scanning electron microscopy. The antennal flagellum of male and female has six types of sensilla: long trichodea, short trichodea, chaetica, coeloconicum around spines, camaniformia and styloconica. There are sexual differences in antennae of P. indica. The female antenna has a coeloconicum sensillum without spines nearby the long trichodea sensilla on ninth flagellomere. Otherwise, auricillica sensilla are distribute on the basal segment of male antenna. These structures are not showed in the female antenna. There are a lot of pores on the hair tufts of the male hair-pencils.
        4,000원
        7.
        2005.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Hemicycliophora minora Wu, 1966와 Pratylenchoides ivanovae Ryss, 1980를 국내 미기록종으로 보고한다. 현재 국내에는 Hemicycliophora속에서 총 5종, Pratylenchoides속에서 총 3종의 선충이 보고되었으며, 이들 종에 대한 검색표를 첨부하였다. 아울러 주사전자현미경을 이용하여 Pratylenchoides utahensis Baldwin, Luc & Bell 와 Rotylenchus feroxcis Eroshenko의 형태적 특징을 추가적으로 기록하였다.
        4,000원
        18.
        2020.09 KCI 등재 서비스 종료(열람 제한)
        생물체의 활동 특히 미생물의 활동은 직·간접적으로 전 지구적으로 분포하는 퇴적물 및 암석 내부 광물의 형성 및 변형에 영향을 주고, 일부는 특징적인 생물기원구조를 형성한다. 특히, 특징적인 생물기원구조에 분포하는 광물은 기존에 알려진 무기적 과정을 통하여 형성되기 어려운 환경에서 형성되기도 하고, 무기적 과정을 통하여 형성된 광물과는 다른 물성 및 특성을 나타낸다. 이러한 생물체의 영향을 받아 형성된 생물기원구조에 대해 연구·분석하는 것은 새로운 광물 형성 메커니즘을 규명하는데 필수적이라 할 수 있다. 따라서 본 논문은 심해저 망간각 및 해저열수분출공 지역 미생물 매트 시료를 예로 들어, 주사전자현미경 분석을 통한 자연환경에 분포하는 생물기원구조 관찰에 대해 소개하고 분석방법, 장점 및 활용에 대해 설명하고자 한다.