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        검색결과 9

        1.
        2022.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, using deep learning, super-resolution images of transmission electron microscope (TEM) images were generated for nanomaterial analysis. 1169 paired images with 256  256 pixels (high resolution: HR) from TEM measurements and 32  32 pixels (low resolution: LR) produced using the python module openCV were trained with deep learning models. The TEM images were related to DyVO4 nanomaterials synthesized by hydrothermal methods. Mean-absolute-error (MAE), peak-signal-to-noise-ratio (PSNR), and structural similarity (SSIM) were used as metrics to evaluate the performance of the models. First, a super-resolution image (SR) was obtained using the traditional interpolation method used in computer vision. In the SR image at low magnification, the shape of the nanomaterial improved. However, the SR images at medium and high magnification failed to show the characteristics of the lattice of the nanomaterials. Second, to obtain a SR image, the deep learning model includes a residual network which reduces the loss of spatial information in the convolutional process of obtaining a feature map. In the process of optimizing the deep learning model, it was confirmed that the performance of the model improved as the number of data increased. In addition, by optimizing the deep learning model using the loss function, including MAE and SSIM at the same time, improved results of the nanomaterial lattice in SR images were achieved at medium and high magnifications. The final proposed deep learning model used four residual blocks to obtain the characteristic map of the low-resolution image, and the super-resolution image was completed using Upsampling2D and the residual block three times.
        4,000원
        2.
        2014.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, nano-scale copper powders were reduction treated in a hydrogen atmosphere at the relativelyhigh temperature of 350℃ in order to eliminate surface oxide layers, which are the main obstacles for fabricating anano/ultrafine grained bulk parts from the nano-scale powders. The changes in composition and microstructure beforeand after the hydrogen reduction treatment were evaluated by analyzing X-ray diffraction (XRD) line profile patternsusing the convolutional multiple whole profile (CMWP) procedure. In order to confirm the result from the XRD lineprofile analysis, transmitted electron microscope observations were performed on the specimen of the hydrogen reduc-tion treated powders fabricated using a focused ion beam process. A quasi-statically compacted specimen from the nano-scale powders was produced and Vickers micro-hardness was measured to verify the potential of the powders as thebasis for a bulk nano/ultrafine grained material. Although the bonding between particles and the growth in size of theparticles occurred, crystallites retained their nano-scale size evaluated using the XRD results. The hardness results dem-onstrate the usefulness of the powders for a nano/ultrafine grained material, once a good consolidation of powders isachieved.
        4,000원
        3.
        2012.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We present a method of graphene synthesis with high thickness uniformity using the thermal chemical vapor deposition (TCVD) technique; we demonstrate its application to a grid supporting membrane using transmission electron microscope (TEM) observation, particularly for nanomaterials that have smaller dimensions than the pitch of commercial grid mesh. Graphene was synthesized on electron-beam-evaporated Ni catalytic thin films. Methane and hydrogen gases were used as carbon feedstock and dilution gas, respectively. The effects of synthesis temperature and flow rate of feedstock on graphene structures have been investigated. The most effective condition for large area growth synthesis and high thickness uniformity was found to be 1000˚C and 5 sccm of methane. Among the various applications of the synthesized graphenes, their use as a supporting membrane of a TEM grid has been demonstrated; such a grid is useful for high resolution TEM imaging of nanoscale materials because it preserves the same focal plane over the whole grid mesh. After the graphene synthesis, we were able successfully to transfer the graphenes from the Ni substrates to the TEM grid without a polymeric mediator, so that we were able to preserve the clean surface of the as-synthesized graphene. Then, a drop of carbon nanotube (CNT) suspension was deposited onto the graphene-covered TEM grid. Finally, we performed high resolution TEM observation and obtained clear image of the carbon nanotubes, which were deposited on the graphene supporting membrane.
        4,000원
        4.
        2011.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We study the relationships between the thermal emissivity of nuclear graphites (IG-110, PCEA, IG-430 and NBG-18) and their surface structural change by oxidation using scanning electron microscope and X-ray diffraction (XRD). The nonoxidized (0% weight loss) specimen had the surface covered with glassy materials and the 5% and 10% oxidized specimens, however, showed high roughness of the surface without glassy materials. During oxidation the binder materials were oxidized first and then graphitic filler particles were subsequently oxidized. The 002 interlayer spacings of the non-oxidized and the oxidized specimens were about 3.38~3.39a. There was a slight change in crystallite size after oxidation compared to the nonoxidized specimens. It was difficult to find a relationship between the thermal emissivity and the structural parameters obtained from the XRD analysis.
        4,000원
        5.
        2010.10 구독 인증기관·개인회원 무료
        Bombus terrestris was released for pollination of apple flowers at apple orchards in Uileumgol, Milyang-sity, mid spring, 2008. Numbers of out-going bees and in-coming bees were 38heads at 10 a.m. and 23heads at 4 p.m., respectively. 75% bees per total in-coming bees collected the pollens about 10 a.m. and 63% bees per total in-coming bees collected the pollens around 4 p.m.. The SEM photography(A) showed that 82.7% of a pollen load were collected on apple flowers and 17.3% of a pollen load were collected from another plants and trees flowers. The another SEM photography(B) showed that 89.1% of a pollen load were collected on apple flowers and 10.9% of a pollen load were collected from another plants and trees flowers. Therefore these results show that B. terrestris mainly pollinates on the apple flowers but the bee seems to visit flowers of other plant species from time to time.
        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
        8.
        1991.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Dacetini족의 1미기록종이 Smithistruma japonica(Ito)가 거금도에서 채집확인 되었기에 한국명을 톱니비늘개미속 톱니비늘개미로 명명 기재하여 보고하며, 주사전자현미경을 사용하여 비늘개비와 톱니비늘개미의 형질특성 차이에 대하여 기재한다. 한국산 비늘개비족(Dacetini tribe)은 모두 2속 2종이 된다.
        4,000원