• Title/Summary/Keyword: Light microscopy

Search Result 1,397, Processing Time 0.027 seconds

Enhanced Photocatalytic Properties of Visible Light Responsive La/TiO2-Graphene Composites for the Removal of Rhodamin B in Water

  • Areerob, Yonrapach;Oh, Won-Chun
    • Journal of the Korean Chemical Society
    • /
    • v.61 no.4
    • /
    • pp.168-178
    • /
    • 2017
  • $La/TiO_2$ - graphene composites were synthesized in this study, and applied to the photocatalytic degradation of Rhodamine B (RhB) under UV-visible light irradiation. X-ray diffraction (XRD), surface analysis, X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM), and Transmission electron microscopy (TEM) analysis demonstrated that $La/TiO_2$ nanoparticles were well distributed on the surface of graphene, and formed the heterostructure of $La/TiO_2$-graphene. Compared to the pure $TiO_2$, $La/TiO_2$-graphene composites displayed much higher photocatalytic activities in RhB degradation under UV-visible light irradiation. The photocatalytic data of $La/TiO_2$-graphene composites exhibit extended light absorption in the visible light region, and possess better charge separation capability than that of pure $TiO_2$. The high photocatalytic activity was attributed to the composite's high adsorptivity, extended light absorption, and increased charge separation efficiency, due to the excellent electrical properties of graphene, and the large surface contact between graphene and $La/TiO_2$ nanoparticles.

Electron Microscopic Observations of Endocrine Cells on the Squirrel's Gastrointestinal Tract (다람쥐 소화관의 내분비세포에 관한 전자현미경적 연구)

  • Lee, Hyeung-sik;Lee, Jae-hyun
    • Korean Journal of Veterinary Research
    • /
    • v.26 no.1
    • /
    • pp.19-30
    • /
    • 1986
  • Endocrine cells were observed in the gastrointestinal tract of the squirrels by light microscopy using Grimelius and Masson-Hamperl silver impregnation, and in the stomach and duodenum by electron microscopy. Light microscopically, argyrophil cell decreased gradually in number in the pyloric region and ileum, stomach, duodenum and jejunum and rectum in the order listed. Argentaffin cells were moderately distributed in the stomach, pyloric region and duodenum, while absent in the jejunum, ileum and rectum. Five kinds of cell types, EC, ECL, D, $D_1$ and G cells were identified in the stomach and three kinds of cell types, S, $EC_1$ and $EC_2$ were also identified in the duodenum by electron microscopy. A cilium noted in the cytoplasm of $D_1$-type cell. The species differences in the distribution, size and structure of the secretory granules were discussed.

  • PDF

Morphological Discretion of Basidiospores of the Puftball Mushroom Calostoma by Electron and Atomic Force Microscopy

  • Kim, Mi-Sun;Kim, Ki-Woo;Jung, Hack-Sung
    • Journal of Microbiology and Biotechnology
    • /
    • v.17 no.10
    • /
    • pp.1721-1726
    • /
    • 2007
  • Comparative morphology among species of the genus Calostoma, including C. cinnabarina, C. ravenelii, and C. japonicum, was investigated by scanning electron microscopy and atomic force microscopy. Spore morphology of C. cinnabarina and C. ravenelii showed no dramatic differences by light microcopy and scanning electron microscopy. To differentiate these species, atomic force microscopy was employed. Quantitative analysis of the surface roughness of basidiospores revealed subtle differences in height fluctuation at the nanometer scale between the species of Calostoma. Basidiospores of C. cinnabarina had a relatively rougher surface than those of C. ravenelii at $2.0{\times}2.0\;{\mu}m^2$ scan areas.

Synthesis of GaN nanowires using thermal chemical vapor deposition (열화학기상증착법을 이용한 GaN nanowire 합성)

  • 류승철;이태재;이철진
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
    • /
    • 2001.07a
    • /
    • pp.931-934
    • /
    • 2001
  • GaN nanowires has much interest as one-dimensional materials for blue light LED. GaN-based materials have been the subject of intensive research for blue light emission and high temperature/high power electronic devices. In this letter, the synthesis of GaN nanowires by the reaction of mixture of GaN nanowires by the reaction of mixture of Ga meta and GaN powder with NH$_3$ using thermal chemical vapor deposition is reported. X-ray diffraction, energy dispersive x-ray spectrometer, scanning electron microscopy, and transmission electron microscopy indicate that those GaN nanowires with hexagonal wurtzite structure were about 60nm in diameter and up to several hundreds of micrometers in length.

  • PDF

Synthesis and Characterization of CdSe/graphene Nanocomposites and their Catalytic Reusability Studies under Visible Light Radiation

  • Ali, Asghar;Oh, Won-Chun
    • Journal of the Korean Ceramic Society
    • /
    • v.52 no.6
    • /
    • pp.502-507
    • /
    • 2015
  • We examined the photo catalytic activity and catalytic recyclability of CdSe/graphene nanocomposites fabricated via modified hydrothermal technique. The prepared composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) with energy dispersive X-ray (EDX), transmission electron microscopy (TEM), Raman spectroscopic analysis, and X-ray photoelectron spectroscopy (XPS). The photocatalytic behavior was investigated through decomposition of RBB as a standard dye under visible light radiation. Our results indicate that there is significant potential for graphene based semiconductor hybrids materials to be used as photocatalysts under visible light irradiation for the degradation of organic dyes from industry effluents.

Light and electron microscopical characteristics of Perkinsus sp. from Manila clam, Ruditapes philippinarum, in Korea

  • Ahn Kyoung Jin;Huh Sung-Hoi;Kim Ki Hong
    • Fisheries and Aquatic Sciences
    • /
    • v.3 no.3_4
    • /
    • pp.205-212
    • /
    • 2000
  • Light and electron microscopical characteristics of Perkinsus sp. parasitizing in Manila clam, Ruditapes philippinarum, in Korea were investigated. Trophozoite within the tissue was spherical or ovoid and ranged $2.5-10.5\mu m$ $(mean = 6.2\mu m)$ in diameter. Trophozoite had a nucleus with a prominent nucleolus and a large cytoplasmic vacuole within the cytoplasm. Single trophozoite was phagocytozed by host hemocyte and cluster cells were encapusulated by hemocytes aggregation within the host tissues. Hypnospores incubated in thioglycollate medium (FTM) for 1 to 15 days were also spherical or ovoid and ranged $10-132\mu m$ $(mean\pm S.D.\;:\;44.25\pm 7.91\mu m)$ in diameter. Zoospores were spherical or ovoid, had a nucleus and two flagella. Zoospores contained apical complex, which consisted of conoid, subpellicular microtubules, rhoptries and rectilinear micronemes.

  • PDF

Characterization of Light Effect on Photovoltaic Property of Poly-Si Solar Cell by Using Photoconductive Atomic Force Microscopy (Photoconductive Atomic Force Microscopy를 이용한 빛의 세기 및 파장의 변화에 따른 폴리실리콘 태양전지의 광전특성 분석)

  • Heo, Jinhee
    • Korean Journal of Materials Research
    • /
    • v.28 no.11
    • /
    • pp.680-684
    • /
    • 2018
  • We investigate the effect of light intensity and wavelength of a solar cell device using photoconductive atomic force microscopy(PC-AFM). A $POCl_3$ diffusion doping process is used to produce a p-n junction solar cell device based on a polySi wafer, and the electrical properties of prepared solar cells are measured using a solar cell simulator system. The measured open circuit voltage($V_{oc}$) is 0.59 V and the short circuit current($I_{sc}$) is 48.5 mA. Moreover, the values of the fill factors and efficiencies of the devices are 0.7 and approximately 13.6 %, respectively. In addition, PC-AFM, a recent notable method for nano-scale characterization of photovoltaic elements, is used for direct measurements of photoelectric characteristics in limited areas instead of large areas. The effects of changes in the intensity and wavelength of light shining on the element on the photoelectric characteristics are observed. Results obtained through PC-AFM are compared with the electric/optical characteristics data obtained through a solar simulator. The voltage($V_{PC-AFM}$) at which the current is 0 A in the I-V characteristic curves increases sharply up to $18W/m^2$, peaking and slowly falling as light intensity increases. Here, $V_{PC-AFM}$ at $18W/m^2$ is 0.29 V, which corresponds to 59 % of the average $V_{oc}$ value, as measured with the solar simulator. Furthermore, while the light wavelength increases from 300 nm to 1,100 nm, the external quantum efficiency(EQE) and results from PC-AFM show similar trends at the macro scale but reveal different results in several sections, indicating the need for detailed analysis and improvement in the future.

Microscopic Studies and Simulations of Bloch Walls in Nematic Thin Films

  • Park, Jung-Ok;Zhou, Jian;Srinivasarao, Mohan
    • 한국정보디스플레이학회:학술대회논문집
    • /
    • 2005.07a
    • /
    • pp.493-495
    • /
    • 2005
  • The director profiles of the Bloch walls are directly visualized using fluorescence confocal polarizing microscopy. Both pure twist Bloch walls and diffuse Bloch walls are analyzed. Polar anchoring energy was measured from optical simulation of the transmitted light interference pattern or the fluorescence intensity profile of a pure twist wall..

  • PDF

Ultrastructural Studies of the Nucleus of Cancer Cells

  • Kim Chung-Sook;Lee Yoo-Bock
    • Applied Microscopy
    • /
    • v.5 no.1
    • /
    • pp.21-30
    • /
    • 1975
  • To investigate ultrastructural characteristics of cancer cell nucleus, 29 cases of malignant tumors of 9 different types were examined. The common findings were marked irregularity of nuclear membrane with pronounced infoldings, clumping of heterochromatin along inner nuclear membrane, enlargement and disturbance of configuration and composition of nucleolus, and frequent observations of nuclear bodies and nuclear inclusions. These findings confirm what have been observed by light microscopy, and are also the signes that can be observed in hyperactive cells. Thus, ultrastructural characteristics of cancerous nucleus are the great variability of nuclear size, shape and composition, but none of them appear to be specific.

  • PDF

Luminescence Properties of Blue Light-emitting Diode Grown on Patterned Sapphire Substrate

  • Wang, Dang-Hui;Xu, Tian-Han;Wang, Lei
    • Current Optics and Photonics
    • /
    • v.1 no.4
    • /
    • pp.358-363
    • /
    • 2017
  • In this study, we present a detailed investigation of luminescence properties of a blue light-emitting diode using InGaN/GaN (indium component is 17.43%) multiple quantum wells as the active region grown on patterned sapphire substrate by low-pressure metal-organic chemical vapor deposition (MOCVD). High-resolution X-ray diffraction (HRXRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), Raman scattering (RS) and photoluminescence (PL) measurements are employed to study the crystal quality, the threading dislocation density, surface morphology, residual strain existing in the active region and optical properties. We conclude that the crystalline quality and surface morphology can be greatly improved, the red-shift of peak wavelength is eliminated and the superior blue light LED can be obtained because the residual strain that existed in the active region can be relaxed when the LED is grown on patterned sapphire substrate (PSS). We discuss the mechanisms of growing on PSS to enhance the superior luminescence properties of blue light LED from the viewpoint of residual strain in the active region.