Grain Boundaries and Gas Barrier Property of Graphene Revealed by Dark-Field Optical Microscopy

2017 ◽  
Vol 122 (1) ◽  
pp. 902-910 ◽  
Author(s):  
Dong Ding ◽  
Hiroki Hibino ◽  
Hiroki Ago
Keyword(s):  
Grain Boundaries ◽  
Optical Microscopy ◽  
Dark Field ◽  
Barrier Property ◽  
Gas Barrier

Optics, Optical Methods, and Microscopy

2021 ◽  
pp. 345-407
Author(s):  
Kannan M. Krishnan
Keyword(s):  
Optical Microscopy ◽  
Polarization State ◽  
Three Dimensional ◽  
Polarized Light ◽  
Dark Field ◽  
Optical Methods ◽  
Transverse Waves ◽  
Dark Field Imaging ◽  
Propagation Of Light ◽  
Scanning Optical Microscopy

Propagation of light is described as the simple harmonic motion of transverse waves. Combining waves that propagate on orthogonal planes give rise to linear, elliptical, or spherical polarization, depending on their amplitudes and phase differences. Classical experiments of Huygens and Young demonstrated the principle of optical interference and diffraction. Generalization of Fraunhofer diffraction to scattering by a three-dimensional arrangement of atoms in crystals forms the basis of diffraction methods. Fresnel diffraction finds application in the design of zone plates for X-ray microscopy. Optical microscopy, with resolution given by the Rayleigh criterion to be approximately half the wavelength, works best when tailored to the optimal characteristics of the human eye (λ = 550 nm). Lenses suffer from spherical and chromatic aberrations, and astigmatism. Optical microscopes operate in bright-field, oblique, and dark-field imaging conditions, produce interference contrast, and can image with polarized light. Variants include confocal scanning optical microscopy (CSOM). Metallography, widely used to characterize microstructures, requires polished or chemically etched surfaces to provide optimal contrast. Finally, the polarization state of light reflected from the surface of a specimen is utilized in ellipsometry to obtain details of the optical properties and thickness of thin film materials.

scholarly journals Texture Evolution in AA6082-T6 BFSW Welds: Optical Microscopy and EBSD Characterisation

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3215 ◽  
Author(s):  
Abbas Tamadon ◽  
Dirk J. Pons ◽  
Don Clucas ◽  
Kamil Sued
Keyword(s):  
Grain Boundary ◽  
Grain Boundaries ◽  
Optical Microscopy ◽  
Electron Backscatter Diffraction ◽  
Texture Evolution ◽  
Grain Structure ◽  
Friction Stir ◽  
Fine Grain ◽  
Grain Structures ◽  
Dynamic Recrystallisation

One of the difficulties with bobbin friction stir welding (BFSW) has been the visualisation of microstructure, particularly grain boundaries, and this is especially problematic for materials with fine grain structure, such as AA6082-T6 aluminium as here. Welds of this material were examined using optical microscopy (OM) and electron backscatter diffraction (EBSD). Results show that the grain structures that form depend on a complex set of factors. The motion of the pin and shoulder features transports material around the weld, which induces shear. The shear deformation around the pin is non-uniform with a thermal and strain gradient across the weld, and hence the dynamic recrystallisation (DRX) processes are also variable, giving a range of observed polycrystalline and grain boundary structures. Partial DRX was observed at both hourglass boundaries, and full DRX at mid-stirring zone. The grain boundary mapping showed the formation of low-angle grain boundaries (LAGBs) at regions of high shear as a consequence of thermomechanical nature of the process.

Hyperspectral Dark Field Optical Microscopy of Single Silver Nanospheres

2016 ◽  
Vol 120 (13) ◽  
pp. 7295-7298 ◽  
Author(s):  
Patrick Z. El-Khoury ◽  
Alan G. Joly ◽  
Wayne P. Hess
Keyword(s):  
Optical Microscopy ◽  
Dark Field ◽  
Silver Nanospheres

Post-Leaching Studies of Defect Rodlets

2003 ◽  
Author(s):  
D. H. Wegen ◽  
D. Papaioannou ◽  
J.-P. Glatz ◽  
P. D. W. Bottomly ◽  
M. Amme ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Optical Microscopy ◽  
Fission Products ◽  
Intergranular Attack ◽  
Mox Fuel ◽  
Metallographic Observation ◽  
History Of ◽  
Release Data

UO2 and MOX fuel rodlets are examined by optical microscopy after 5 years leaching in water to correlate the irradiation history of the fuels and of the fuel behaviour and with the release data for fission products and actinides. Metallographic observation revealed a strong intergranular attack of the MOX fuel in contrast to UO2. The latter effect could be responsible for the particularly high releases from the MOX fuel (upto 12% of the Cs inventory), compared to the UO2 fuel (only 0.6% of the Cs inventory). The large inventory of volatile fission products at grain boundaries can be explained by the high linear power rating (350 W/cm) with extremely high central temperatures in the MOX fuel during the irradiation.

Detection and study of magnetic micro-and nanostructures using dark-field optical microscopy

2003 ◽  
Vol 45 (3) ◽  
pp. 519-528 ◽  
Author(s):  
V. I. Belotelov ◽  
A. S. Logginov ◽  
A. V. Nikolaev
Keyword(s):  
Optical Microscopy ◽  
Dark Field

Evolution of gold nanoparticle clusters in living cells studied by sectional dark-field optical microscopy and chromatic analysis

2015 ◽  
Vol 9 (7) ◽  
pp. 738-749 ◽  
Author(s):  
Sheng-Hann Wang ◽  
Chia-Wei Lee ◽  
Fan-Gang Tseng ◽  
Kuo-Kan Liang ◽  
Pei-Kuen Wei
Keyword(s):  
Optical Microscopy ◽  
Gold Nanoparticle ◽  
Living Cells ◽  
Dark Field ◽  
Nanoparticle Clusters
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