• Title/Summary/Keyword: electron lens

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A Simple Method to Determination the Rotation Angle Between an Image and its Diffraction Pattern with LACBED Patterns (LACBED 패턴으로부터 전자현미경 상에 대한 회절도형의 회전각을 측정하는 간단한 방법)

  • Kim, Hwang-Su;Kim, Jong-Pil
    • Applied Microscopy
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    • v.33 no.3
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    • pp.187-193
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    • 2003
  • When electron microscope images and selected area diffraction patterns of crystalline materials are being compared, it is important to know for the rotation of the diffraction pattern with respect to the image caused by the magnetic lens in the Electron Microscope. A well-known method to determine this rotation is to use a test crystal of $MoO_3$. But this method of determination of the rotation angle contains an uncertainty of $180^{\circ}$. Thus one has to devise another way to eliminate this uncertainty. In this paper we present a new and simple method of determining this rotation without any complexity. The method involves a process of obtaining LACBED patterns of crystalline materials. For the J2010 electron microscope, the rotation is determined to be $180^{\circ}$ and this angle remains unchanged for changing of the magnification and the camera length.

Three Dimensional Reconstruction of Cellular Structure in Drosophila Retina Using High Voltage Electron Microscopy (초고압전자현미경을 이용한 초파리 망막 세포의 3차원 구조)

  • Mun, Ji-Young;Lee, Kyung-Eun;Han, Sung-Sik
    • Applied Microscopy
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    • v.39 no.2
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    • pp.185-189
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    • 2009
  • Studies about the structure of Drosophila melanogaster retinal cell using electron microscopy have been carried out in details since 1960s. However, these results can have limitations in functional research because of two-dimensional structure. In this study, the adult retina of Drosophila melanogaster was investigated by employing high pressure freezing method, serial sections, high voltage electron microscopy, and 3-dimensional reconstruction method. From there results, mitochondria, microtubules, and nuclei were reconstructed as 3-dimensional structure using IMOD program. The 3D structure of these organelles showed that mitochondira mainly located in distal region near lens, and microtubule mainly located in distal and basal region. The 3D reconstruction of these organelles can be used for a critical evaluation in the dynamic change of cellular organelles caused by functional abnormality like retinal degeneration.

Dosimetric characteristics of an independent collimator system using measurements performed quarter fields. (Tungsten eyeball shield block의 임상적용에 관한 고찰)

  • Jeong, Deok-Yang;Lee, Byoung-Koo;Hwang, Woong-Koo
    • The Journal of Korean Society for Radiation Therapy
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    • v.14 no.1
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    • pp.89-94
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    • 2002
  • During radiation therapy with electron beam to eyelid, we must keep the minimal dose on eyeball as possible. especially in the treatment of Sebaceous gland carcinoma, Squamouse cell ca., and basal cell ca. of eyelid and low grade MALToma etc. But if radiation field covered the upper & lower eyelid, it makes a cataract on lens of treated eye, in late complications. Now we reports the advantages of Tungsten eyeball shielding block compare to previously used lead block. with BOLX-I material, we made a eyeball model and measured the absorbed dose of 6MeV & 9MeV electron hem at 6 point of eyeball model with TLD chip. And compare the absorbed dose to previously lead block and other types of Tungsten eyeball shielding block.

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Hydrogenotrophic Sulfate Reduction in a Gas-Lift Bioreactor Operated at $9^{\circ}C$

  • Nevatalo, Laura M.;Bijmans, Martijn F. M.;Lens, Piet N. L.;Kaksonen, Anna H.;Puhakka, Jaakko A.
    • Journal of Microbiology and Biotechnology
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    • v.20 no.3
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    • pp.615-621
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    • 2010
  • The viability of low-temperature sulfate reduction with hydrogen as electron donor was studied with a bench-scale gas-lift bioreactor (GLB) operated at $9^{\circ}C$. Prior to the GLB experiment, the temperature range of sulfate reduction of the inoculum was assayed. The results of the temperature gradient assay indicated that the inoculum was a psychrotolerant mesophilic enrichment culture that had an optimal temperature for sulfate reduction of $31^{\circ}C$, and minimum and maximum temperatures of $7^{\circ}C$ and $41^{\circ}C$, respectively. In the GLB experiment at $9^{\circ}C$, a sulfate reduction rate of 500-600 mg $l^{-1}d^{-1}$, corresponding to a specific activity of 173 mg ${SO_4}^{2-}g\;VSS^{-1}d^{-1}$, was obtained. The electron flow from the consumed $H_2$-gas to sulfate reduction varied between 27% and 52%, whereas the electron flow to acetate production decreased steadily from 15% to 5%. No methane was produced. Acetate was produced from $CO_2$ and $H_2$ by homoacetogenic bacteria. Acetate supported the growth of some heterotrophic sulfate-reducing bacteria. The sulfate reduction rate in the GLB was limited by the slow biomass growth rate at $9^{\circ}C$ and low biomass retention in the reactor. Nevertheless, this study demonstrated the potential sulfate reduction rate of psychrotolerant sulfate-reducing mesophiles at suboptimal temperature.

펜던트형 감성조명 LED 등기구 모듈개발

  • Seo, Dong-Won;Kim, Yeong-Geun;Kim, Jin-Sa;Kim, Geum-Taek;Choe, Un-Sik;Song, Min-Jong;Song, Myeong-Hyeon;Park, Chun-Bae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.11a
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    • pp.264-264
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    • 2009
  • The sensitivity lighting of pendant type used Micro-controller AVR, embodiment method for Munsell chromaticity diagram system and adoption method for light source lens respectively. About a plan design of light fixture, LED circuit designed flow chart of circuits and LED driver of organizations in electron device. For used Solidworks soft ware program, LED light source must take a heat shink part and LED light fixture module for sensitivity lighting of pendant type into considerations

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Studies on semiconducting metal-oxide(ZnO) Nanoweb from Electrospinning (전기방사를 이용한 반도체 산화물(ZnO) 나노웹 제조에 관한 연구)

  • Jo, Na-Gyeong;Kim, Han-Seong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.11a
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    • pp.253-253
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    • 2009
  • Electrospinning is one of the simple, cost- efficient methods to produce long continuous semiconducting oxide nanofibers. Polyvinyl Alcohol (PVA) and zinc acetate were used. PVA/Zinc acetate aqueous solutions were electrospun into nonwoven webs. CCD camera, with a lens of long working distance and digital video board were used in capturing the drop and web deposition. The diameter and morphology of nanofibers were analyzed with a Field-emission scanning electron microscopy (FE-SEM). In this study, the average diameter and morphology of nanofibers have been explorered.

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Infrared Scanning Near-Field Optical Microscopy (IR-SNOM) Below the Diffraction Limit

  • Sanghera, J.S.;Aggarwal, I.D.;Cricenti, A.;Generossi, R.;Luce, M.;Perfetti, P.;Margoritondo, G.;Tolk, N.;Piston, D.
    • Ceramist
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    • v.10 no.3
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    • pp.55-66
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    • 2007
  • Infrared Scanning Near-field Optical Microscopy (IR-SNOM) is an extremely powerful analytical instrument since it combines IR spectroscopy's high chemical specificity with SNOM's high spatial resolution. In order to do this in the infrared, specialty chalcogenide glass fibers were fabricated and their ends tapered to generate SNOM probes. The fiber tips were installed in a modified near field microscope and both inorganic and biological samples illuminated with the tunable output from a free-electron laser located at Vanderbilt University. Both topographical and IR spectral images were simultaneously recorded with a resolution of ${\sim}50\;nm$ and ${\sim}100\;nm$, respectively. Unique spectroscopic features were identified in all samples, with spectral images exhibiting resolutions of up to ${\lambda}/60$, or at least 30 times better than the diffraction limited lens-based microscopes. We believe that IR-SNOM can provide a very powerful insight into some of the most important bio-medical research topics.

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The Study of the Ultrastructure on the Rigid Gas Permeable Contact Lenses (Rigid Gas Permeable Contact Lenses의 미세구조에 대한 연구)

  • Kim, Douk-Hoon
    • Journal of Korean Ophthalmic Optics Society
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    • v.3 no.1
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    • pp.259-262
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    • 1998
  • The Anterior surface and posterior surface of rigid gas permeable(RGP) contact lenses has been studied by scanning electron microscopy. Results point out that the ultrastructure of contact lenses surface was some different on the anterior and posterior surface of RGP. The Quantitative study of surface roughness suggest that the anterior surface was more smooth than the posterior surface. These results suggest that the materials characters appeared the contact lens surface. The morphology of the anterior and posterior surface have different, Maybe, these result have a manufacture processing of the contact lenses. But some surface appeared a foreign body particles.

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Synthesis and Properties of Ca8Gd2(PO4)6O2 Nano-Crystalline Structures

  • Bharat, L. Krishna;Yu, Jae Su
    • Proceedings of the Korean Vacuum Society Conference
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    • 2013.08a
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    • pp.286.1-286.1
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    • 2013
  • Nowadays, the glare towards the light-emitting diode (LED) lighting source has much attention due to its eco-friendly nature, reduced energy consumption, and low CO2 emission. LEDs can show versatile colors by changing the composition ratio of semiconductors. Phosphors re-emit light by absorbing light from LED, which is the key factor for emission. The endeavor to make replica of natural white light is increasing day by day. Industrially, blue LED chip crowned with a yellow phosphor coated lens gives low quality white light. Newly, many researchers are introducing modern approaches, adding red phosphor to the yellow phosphor to increase the quality of white light. Here, we synthesized structurally and chemically stable europium doped oxyapatite Ca8Gd2(PO4)6O2 nano-crystalline structures by a hydrothermal method. The ultrafine structures were formed due to the effect of ethylenediaminetetraacetic acid, which is confirmed by the transmission electron microscope images. The structural properties were analyzed using the X-ray diffraction patterns.

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Fabrication of ZnO Nanowires by Green Technology (녹색기술을 이용하여 제작된 ZnO 나노선)

  • Lee, Geun-Hyoung
    • Korean Journal of Metals and Materials
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    • v.50 no.3
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    • pp.233-236
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    • 2012
  • ZnO nanowires were fabricated through thermal evaporation of Zn or ZnS powder using solar energy. The Zn or ZnS powder was heated and evaporated by sunlight. The sunlight was concentrated on the Zn or ZnS powder by a converging lens and then the Zn or ZnS powder was evaporated and oxidized in air. After oxidation, ZnO nanowires were fabricated in the focal point. Strong ultraviolet emission, which corresponds to the near band-edge emission, was observed from the ZnO nanowires synthesized using Zn powder as a source material. Meanwhile, green emission, related to intrinsic defects such as oxygen vacancies, prevailed for the ZnO nanowires fabricated using ZnS powder. No catalysts were used in the fabrication of the ZnO nanowires, which suggested the ZnO nanowires were grown by a vapor-solid mechanism.