Three-dimensional quantification of composition and electrostatic potential at individual grain boundaries in doped ceria

2016 ◽  
Vol 4 (14) ◽  
pp. 5167-5175 ◽  
Author(s):  
David R. Diercks ◽  
Jianhua Tong ◽  
Huayang Zhu ◽  
Robert Kee ◽  
George Baure ◽  
...  
Keyword(s):  
Grain Boundaries ◽  
Electrostatic Potential ◽  
Three Dimensional ◽  
Electrostatic Potentials ◽  
Nanometer Scale ◽  
Doped Ceria

Three-dimensional nanometer-scale quantification of all species is made around grain boundaries in Nd-doped CeO2allowing three-dimensional determination of electrostatic potentials.

scholarly journals Evaluation of Electrostatic Potentials and Madelung Constants in Ionic Crystals by the Method of Spherically Symmetric Equivalent Charges

1992 ◽  
Vol 45 (2) ◽  
pp. 239 ◽  
Author(s):  
DN Argyriou ◽  
CJ Howard
Keyword(s):  
Electrostatic Potential ◽  
Three Dimensional ◽  
Electrostatic Potentials ◽  
Spherically Symmetric ◽  
Ionic Crystals ◽  
Interaction Energies ◽  
Spherical Charge ◽  
Simple Derivation ◽  
Charge Distributions ◽  
Electrostatic Calculations

A simple derivation is given of the electrostatic potential in a periodic three-dimensional array of spherically symmetric charge distributions. By noting the equivalence in electrostatic calculations of point charges and suitably chosen spherical charge distributions, this leads to expressions for electrostatic potentials and (Madelung) interaction energies in ionic crystals. The expressions involve sums in reciprocal space only. The approach is illustrated by the calculation of Madelung constants for NaCl and CaF2, and the electrostatic interaction energy of Ti02 (rutile). A previous controversy is resolved by showing that the two expressions for the electrostatic potential, which are apparently different, under certain conditions give the same result.

Conformation of Ribosomes from Escherichia Coli

1974 ◽  
Vol 32 ◽  
pp. 210-211
Author(s):  
M. Boublik ◽  
W. Hellmann ◽  
F. Jenkins
Keyword(s):  
Binding Sites ◽  
Ribosomal Proteins ◽  
Fluorescent Dyes ◽  
Protein Biosynthesis ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Dimensional Structure ◽  
Complete Understanding ◽  
And Function

The present knowledge of the three-dimensional structure of ribosomes is far too limited to enable a complete understanding of the various roles which ribosomes play in protein biosynthesis. The spatial arrangement of proteins and ribonuclec acids in ribosomes can be analysed in many ways. Determination of binding sites for individual proteins on ribonuclec acid and locations of the mutual positions of proteins on the ribosome using labeling with fluorescent dyes, cross-linking reagents, neutron-diffraction or antibodies against ribosomal proteins seem to be most successful approaches. Structure and function of ribosomes can be correlated be depleting the complete ribosomes of some proteins to the functionally inactive core and by subsequent partial reconstitution in order to regain active ribosomal particles.

Determination of the lattice translation across {110} APBs in GaAs

1988 ◽  
Vol 46 ◽  
pp. 600-601
Author(s):  
D.R. Rasmussen ◽  
N.-H. Cho ◽  
C.B. Carter
Keyword(s):  
Grain Boundaries ◽  
Lower Energy ◽  
Antiphase Boundary ◽  
The Other ◽  
Boundary Structure ◽  
Interface Plane ◽  
Inversion Symmetry ◽  
High Angle ◽  
Equilibrium Distance

Domains in GaAs can exist which are related to one another by the inversion symmetry, i.e., the sites of gallium and arsenic in one domain are interchanged in the other domain. The boundary between these two different domains is known as an antiphase boundary [1], In the terminology used to describe grain boundaries, the grains on either side of this boundary can be regarded as being Σ=1-related. For the {110} interface plane, in particular, there are equal numbers of GaGa and As-As anti-site bonds across the interface. The equilibrium distance between two atoms of the same kind crossing the boundary is expected to be different from the length of normal GaAs bonds in the bulk. Therefore, the relative position of each grain on either side of an APB may be translated such that the boundary can have a lower energy situation. This translation does not affect the perfect Σ=1 coincidence site relationship. Such a lattice translation is expected for all high-angle grain boundaries as a way of relaxation of the boundary structure.

scholarly journals Meso-Scale Transmission Electron Microscope Tomography Applied for Wax Distribution in Toner Particles

2013 ◽  
Vol 19 (S5) ◽  
pp. 58-61 ◽  
Author(s):  
Mino Yang ◽  
Jun-Ho Lee ◽  
Hee-Goo Kim ◽  
Euna Kim ◽  
Young-Nam Kwon ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Three Dimensional ◽  
Chromatic Aberration ◽  
Laser Printer ◽  
Medium Voltage ◽  
Transmission Electron ◽  
Z Contrast ◽  
Contrast Image

AbstractDistribution of wax in laser printer toner was observed using an ultra-high-voltage (UHV) and a medium-voltage transmission electron microscope (TEM). As the radius of the wax spans a hundred to greater than a thousand nanometers, its three-dimensional recognition via TEM requires large depth of focus (DOF) for a volumetric specimen. A tomogram with a series of the captured images would allow the determination of their spatial distribution. In this study, bright-field (BF) images acquired with UHV-TEM at a high tilt angle prevented the construction of the tomogram. Conversely, the Z-contrast images acquired by the medium-voltage TEM produced a successful tomogram. The spatial resolution for both is discussed, illustrating that the image degradation was primarily caused by beam divergence of the Z-contrast image and the combination of DOF and chromatic aberration of the BF image from the UHV-TEM.

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