scholarly journals Spectroscopy of nanoscale crystalline structural elements

2020 ◽  
Vol 99 (3) ◽  
pp. 46-53
Author(s):  
Y.V. Borodin ◽  
◽  
K.V. Sysolov ◽  
V.R. Rande ◽  
G.V. Vavilova ◽  
...  
Keyword(s):  
Electronic States ◽  
Optical Methods ◽  
High Electron ◽  
Structural Elements ◽  
Conventional Theory ◽  
Point Symmetry Group ◽  
Electron Microscopic ◽  
X Ray ◽  
Nanoscale Structures ◽  
Microscopic Studies

The study of structural elements, nanoparticles, microblocks and other nanoscale objects was an important part of the study of crystals non-equilibrium properties. The behavior of nanoscale structures allows us to judge the dynamics of the crystal lattice during doping, deformation, and interactions with radiation. Along with x-ray and electron microscopic studies, optical methods for determining the size of nanoscale objects, the energy of their electrons, and the symmetry of electronic States are increasingly being used. Among nanoscale objects, proton-separated structural elements (PSE) attract special attention in connection with the development of crystal structure block-hierarchical (BH) model. In this paper, we consider the possibility of calculating the size of PSE crystals in a model of quantum-dimensional structures. According to this model except values of the crystal potential in PSE, you should consider the area of high electron density, the existence of which is beyond the scope of conventional theory. Experimental data allow us to determine the position of this zone as localized around the atomic core of the PSE. Note that the atomic backbone generally coincides with the unit cell, that is, it consists of the same number of atoms and has the same point symmetry group.

Chrysiasis: electron microscopic studies and X-ray microanalysis

1984 ◽  
Vol 9 (2) ◽  
pp. 174-180 ◽  
Author(s):  
F. SCHULTZ LARSEN ◽  
H. BOYE ◽  
E. HAGE
Keyword(s):  
Electron Microscopic ◽  
X Ray ◽  
Microscopic Studies

Synthesis of nanometer-sized particles of barium orthotitanate prepared through a modified reverse micellar route: Structural characterization, phase stability and dielectric properties

2004 ◽  
Vol 19 (10) ◽  
pp. 2905-2912 ◽  
Author(s):  
Tokeer Ahmad ◽  
Ashok K. Ganguli
Keyword(s):  
Martensitic Transition ◽  
Line Broadening ◽  
X Ray Diffraction ◽  
Electron Microscopic ◽  
X Ray ◽  
Transmission Electron ◽  
Transmission Electron Microscopic ◽  
Microscopic Studies ◽  
Size Of Particles ◽  
Reverse Micellar

Nanoparticles of barium orthotitanate (Ba2TiO4) was obtained using microemulsions (avoiding Ba-alkoxide). Powder x-ray diffraction studies of the powder after calcining at 800 °C resulted in a mixture of orthorhombic (70%) and monoclinic (30%) phases. The high-temperature orthorhombic form present at 800 °C was due to the small size of particles obtained by the reverse micellar route. Pure orthorhombic Ba2TiO4 was obtained on further sintering at 1000 °C with lattice parameters a = 6.101(2) Å, b =22.94(1) Å, c = 10.533(2) Å (space group, P21nb). The particle size obtained from x-ray line broadening studies and transmission electron microscopic studies was found to be 40–50 nm for the powder obtained after heating at 800 °C. Sintering at 1000 °C showed increase in grain size up to 150 nm. Our studies corroborate well with the presence of a martensitic transition in Ba2TiO4. The dielectric constant was found to be 40 for Ba2TiO4 (at 100 kHz) for samples sintered at 1000 °C. The dielectric loss obtained was low (0.06) at 100 kHz.

Electron Microscopy of Alcohol Oxidase Crystals from Pichia Pastoris

1990 ◽  
Vol 48 (1) ◽  
pp. 108-109
Author(s):  
Janet Vonck ◽  
Ernst F.J. van Bruggen
Keyword(s):  
Pichia Pastoris ◽  
Hansenula Polymorpha ◽  
Alcohol Oxidase ◽  
Unit Cell ◽  
Electron Microscopic ◽  
X Ray ◽  
X Ray Crystallography ◽  
Cell Dimensions ◽  
Microscopic Studies ◽  
Unit Cell Dimensions

Several yeast species are able to grow on methanol. When they are grown in a methanol-restricted culture, their peroxisomes contain large crystalline inclusions, consisting of alcohol oxidase (AOX). A monomer of AOX has a molecular weight of ca. 74,000. Inside the peroxisome, AOX occurs as octamers.Electron microscopic studies of AOX from Hansenula polymorpha have revealed that the eight subunits are slightly elongated and form two layers of four, which are twisted relative to each other. The molecule measures ca. 12 nm in all directions.Recently, crystals suitable for x-ray diffraction have been formed of AOX from Pichia pastoris . The space group is P21, with unit cell dimensions a=157.3Å, b=171.45Å, c=231.6Å, β=94°. These dimensions indicate that the unit cell contains four octamers, too much to solve by x-ray crystallography alone. Therefore, we have started an EM study of the crystals, to get information about the organization of the molecules in the crystal lattice.

X-Ray Line Broadening and Electron Microscopic Studies on ZnTe Thin Films

1989 ◽  
Vol 111 (2) ◽  
pp. 515-522 ◽  
Author(s):  
U. Pal ◽  
S. Saha ◽  
B. K. Samantaray ◽  
H. D. Banerjee ◽  
A. K. Choudhuri
Keyword(s):  
Thin Films ◽  
Line Broadening ◽  
Electron Microscopic ◽  
X Ray ◽  
Microscopic Studies ◽  
Znte Thin Films

X-ray and electron-microscopic studies of a sodium-rich low plagioclase

1970 ◽  
Vol 131 (1-6) ◽  
pp. 418-436 ◽  
Author(s):  
M. Korekawa ◽  
H.-U. Nissen ◽  
D. Philipp
Keyword(s):  
Electron Microscopic ◽  
X Ray ◽  
Microscopic Studies
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