Ultrastructure, organization and cytochemistry of cytoplasmic crystalline inclusions in Origanum dictamnus L. leaf chlorenchyma cells

1983 ◽  
Vol 64 (1) ◽  
pp. 231-244
Author(s):  
A.M. Bosabalidis ◽  
D. Papadopoulos
Keyword(s):  
Rectangular Prism ◽  
Square Lattice ◽  
Tetragonal Symmetry ◽  
Pepsin Digestion ◽  
Crystalline Inclusions ◽  
Double Helices ◽  
Diffraction Patterns ◽  
Crystallographic Planes

In the cytoplasm of chlorenchyma cells in primary Origanum dictamnus leaves, rectangular prism-like crystals occur, which, as shown by pepsin digestion, are proteinaceous. In sections they usually show either a square lattice or striations running parallel to the short or long axis. In both cases the interspacings are estimated to be about 100 A, suggesting that the arrangement of the crystallographic planes possesses tetragonal symmetry. High magnifications of the crystalline inclusions together with analysis of their diffraction patterns showed that the striations are composed of double helices of protein macromolecules. In leaves 3–4 mm long, eroded crystals are often observed. When leaves are larger than 5 mm, no crystalline bodies can be identified in chlorenchyma cells. It is possible that they represent a storage form of protein, which is used later by the developing cells.

The Structure of the Macromolecular Units on the Cell Walls of Bacillus Polymyxa

1967 ◽  
Vol 2 (4) ◽  
pp. 587-591
Author(s):  
J. T. FINCH ◽  
A. KLUG ◽  
M.V. NERMUT
Keyword(s):  
Cell Wall ◽  
Electron Micrographs ◽  
Electron Scattering ◽  
Cell Walls ◽  
Single Layer ◽  
Optical Diffraction ◽  
Square Lattice ◽  
Bacillus Polymyxa ◽  
Optical Filtering ◽  
Diffraction Patterns

Electron micrographs of negatively stained preparations of cell walls of Bacillus polymyxa have been investigated by optical diffraction and optical filtering techniques. Images of single layers of the cell wall, from which the ‘noise’ has been filtered optically, show hollow, square-shaped morphological units arranged on a square lattice of side 100 Å. Single-layer images showing the same pattern have been filtered from moiré patterns arising from two overlapping single layers. The morphological units are composed of four smaller subunits. The optical diffraction patterns from regions of two overlapping layers show extra reflexions which are attributed to multiple electron scattering.

scholarly journals Optical diffraction of the Z lattice in canine cardiac muscle.

1977 ◽  
Vol 75 (3) ◽  
pp. 818-836 ◽  
Author(s):  
M A Goldstein ◽  
J P Schroeter ◽  
R L Sass
Keyword(s):  
Cardiac Muscle ◽  
Electron Micrographs ◽  
Cross Sections ◽  
Optical Diffraction ◽  
Square Lattice ◽  
Thin Sections ◽  
Diffraction Patterns ◽  
Nemaline Rods

Optical diffraction patterns from electron micrographs of both longitudinal and cross sections of normal and anomalous canine cardiac Z bands have been compared. The data indicate that anomalous cardiac Z bands resembling nemaline rods are structurally related to Z bands in showing a repeating lattice common to both. In thin sections transverse to the myofibril axis, both electron micrographs and optical diffraction patterns of the Z structure reveal a square lattice of 24 nm. This lattice is simple at the edge of each I band and centered in the interior of the Z band, where two distinct lattice forms have been observed. In longitudinal sections, oblique filaments visible in the electron micrographs correspond to a 38-nm axial periodicity in diffraction patterns of both Z band and Z rod. We conclude that the Z rods will be useful for further analysis and reconstruction of the Z lattice by optical diffraction techniques.

Powder X-Ray Diffraction Characterization of Laser Deposited Ferroelectric Thin Films

1991 ◽  
Vol 35 (A) ◽  
pp. 211-220
Author(s):  
W. Wong-Ng ◽  
T.C. Huang ◽  
L.P. Cook ◽  
P.K. Schenck ◽  
M.D. Vaudin ◽  
...  
Keyword(s):  
Thin Films ◽  
Substrate Surface ◽  
Analytical Techniques ◽  
Surface Strain ◽  
Tetragonal Symmetry ◽  
X Ray Diffraction ◽  
X Ray ◽  
Peak Splitting ◽  
Pzt Films ◽  
Diffraction Patterns

AbstractThin films of BaTiO3 and Pb(Zr53 Ti47)O3 (PZT) have been deposited on Pt and Pt-coated silicon substrates using both Nd-YAG and excimer lasers. The BaTiO3 films were prepared using heated substrates and were crystalline. The PZT films were deposited at room temperature and were amorphous; on annealing, they crystallized and gave rise to well-defined powder x-ray diffraction patterns.To compare and correlate the properties and processing conditions of these thin films, characterizations were performed using a variety of analytical techniques including x-ray diffraction, TEM, SEM/EDX and ferroelectric and dielectric property measurements. The x-ray diffraction technique was used for identifying the various phases formed and also for analyzing the profiles of the diffraction peaks. Both the PZT films annealed below 800°C and the BaTiO3 films typically show polycrystalline x-ray diffraction patterns corresponding to a pseudo-cubic structure (i.e no peak splitting) instead of the tetragonal patterns characteristic of the target materials. It was found that for the BaTiO3 films the pseudosymmetry was due to crystallographic alignment of the longer c-axis In the substrate surface to relieve strain. In the FZT films annealed below 900°C, it is suggested that the residual surface strain and/or small crystallite size of these materials may have precluded the peak splitting; at higher annealing temperatures, the tetragonal symmetry was recovered.

scholarly journals Microtextural Characterization of a Beryllium Weldment

1995 ◽  
Vol 23 (1) ◽  
pp. 7-19 ◽  
Author(s):  
Stuart I. Wright ◽  
James D. Cotton
Keyword(s):  
Electron Backscatter Diffraction ◽  
Growth Direction ◽  
Fracture Plane ◽  
Grain Orientations ◽  
Diffraction Patterns ◽  
Crystallographic Planes ◽  
Individual Grains ◽  
Backscatter Diffraction ◽  
Growth Analyses

Local grain orientations in a beryllium weldment have been characterized using an automatic technique based on computer indexing of electron backscatter diffraction patterns. The results indicate that many weld grains are epitaxially nucleated from the base metal. The number of grains allowed further growth is quickly reduced based on their orientations relative to the macroscopic growth direction. Grains with <101¯0> crystallographic directions parallel to the macroscopic growth direction tend to dominate. Examination of the spatial distribution of orientation within individual grains shows that, while the macroscopic growth direction changes during solidification, the crystallographic orientation does not. That is, substantial deformation of the weld grains does not occur during grain growth. Analyses adjacent to the centerline fracture indicate that the fracture plane correlates best with {112¯0} crystallographic planes.

Dielectric Behavior and Impedance Spectroscopy of Ba1-xBixTi1-xFexO3 System

2012 ◽  
Vol 585 ◽  
pp. 190-194 ◽  
Author(s):  
Arvind Kumar ◽  
R.K Dwivedi ◽  
Vijayeta Pal
Keyword(s):  
Impedance Spectroscopy ◽  
Spectroscopic Studies ◽  
Dielectric Behavior ◽  
Tetragonal Symmetry ◽  
X Ray Diffraction ◽  
Cubic Symmetry ◽  
Thermally Activated ◽  
State Ceramic ◽  
Diffraction Patterns ◽  
Single Phase Formation

Studies on the analysis of impedance spectroscopy of polycrystalline samples with compositions x ≤ 0.20 in the system Ba1-xBixTi1-xFexO3 are made. For this all the samples are prepared using solid state ceramic route. Preliminary X-ray diffraction patterns showed single phase formation of all compositions with tetragonal symmetry for x = 0.02 and cubic symmetry for compositions with x ≥ 0.10. For composition with x = 0.02, the dielectric anomaly at ~100 °C indicates paraelectric to ferroelectric transition. Impedance spectroscopic studies over the temperature range 25 °C to 180 °C have shown the presence of both bulk and grain boundary effects. The bulk conductivity has exhibited Arrehenius type thermally activated hopping process which is supported by ac conductivity behavior as a function of frequency.

Characterization of an Inorganic Cryptomelane Nanomaterial Synthesized by a Novel Process Using Transmission Electron Microscopy and X-Ray Diffraction

2008 ◽  
Vol 14 (4) ◽  
pp. 328-334 ◽  
Author(s):  
Longzhou Ma ◽  
Thomas Hartmann ◽  
Marcos A. Cheney ◽  
Nancy R. Birkner ◽  
Pradip K. Bhowmik
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Surface ◽  
High Surface Area ◽  
Rietveld Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Potential Applications ◽  
Diffraction Patterns ◽  
Crystallographic Planes

Layer- and tunnel-structured manganese oxide nanomaterials are important because of their potential applications in industrial catalysis. A novel soft chemistry method was developed for the synthesis of inorganic cryptomelane nanomaterials with high surface area. Bright field transmission electron microscopy (BF-TEM) and high-resolution transmission electron microscopy (HRTEM) techniques were employed to characterize this nanomaterial. A nanosized material with fibrous texture comprised of 140–160 nm striations was identified by BF-TEM imaging. HRTEM images show multiple atomic morphologies such as “helix-type,” “doughnut-like,” and tunnel structures lying on different crystallographic planes. The crystallographic parameters of this material were analyzed and measured by X-ray powder diffraction (XRD) showing that the synthesized nanomaterial is single phased and corresponds to cryptomelane with major diffraction peaks (for 10° < 2θ < 60°) at d-spacing values of 6.99, 4.94, 3.13, 2.40, 2.16, 1.84, 1.65, and 1.54 Å. A “doughnut-like” crystal structure was confirmed based on the crystallographic data. Structure and lattice parameters refinement was performed by XRD/Rietveld analysis. Simple simulation of HRTEM images and selected area diffraction patterns were applied to interpret the HRTEM images as observed.

scholarly journals The Effect of Annealing Ambience on the Material and Photodetector Characteristics of Sputtered ZnGa2O4 Films

Nanomaterials ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 2316
Author(s):  
Anoop Kumar Singh ◽  
Shiau-Yuan Huang ◽  
Po-Wei Chen ◽  
Jung-Lung Chiang ◽  
Dong-Sing Wuu
Keyword(s):  
Thermal Annealing ◽  
Crystalline Structure ◽  
Visible Region ◽  
X Ray Diffraction ◽  
Substantial Impact ◽  
Single Crystalline ◽  
X Ray ◽  
Transmission Electron ◽  
Diffraction Patterns ◽  
Crystallographic Planes

Spinel ZnGa2O4 films were grown on c-plane sapphire substrates at the substrate temperature of 400 °C by radio-frequency magnetron sputtering. Post thermal annealing was employed at the annealing temperature of 700 °C in order to enhance their crystal quality. The effect of thermal annealing on the microstructural and optoelectronic properties of ZnGa2O4 films was systematically investigated in various ambiences, such as air, nitrogen, and oxygen. The X-ray diffraction patterns of annealed ZnGa2O4 films showed the crystalline structure to have (111) crystallographic planes. Transmission electron micrographs verified that ZnGa2O4 film annealed under air ambience possesses a quasi-single-crystalline structure. This ZnGa2O4 film annealed under air ambience exhibited a smooth surface, an excellent average transmittance above 82% in the visible region, and a wide bandgap of 5.05 eV. The oxygen vacancies under different annealing ambiences were revealed a substantial impact on the material and photodetector characteristics by X-ray photoelectron spectrum investigations. ZnGa2O4 film exhibits optimal performance as a metal-semiconductor-metal photodetector when annealed under air ambience. Under these conditions, ZnGa2O4 film exhibits a higher photo/dark current ratio of ~104 order, as well as a high responsivity of 2.53 A/W at the bias of 5 V under an incident optical light of 240 nm. These results demonstrate that quasi-single-crystalline ZnGa2O4 films have significant potential in deep-ultraviolet applications.

More features, more tools, moreCrysTBox

2017 ◽  
Vol 50 (4) ◽  
pp. 1226-1234 ◽  
Author(s):  
Miloslav Klinger
Keyword(s):  
Atomic Structure ◽  
Automated Analysis ◽  
Inverse Pole Figure ◽  
Input Image ◽  
Accurate Analysis ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
Diffraction Patterns ◽  
Crystallographic Planes ◽  
Convergent Beam

A new release of theCrysTBoxsoftware is introduced. The original toolbox allows for an automated analysis of transmission electron microscope (TEM) images and for crystallographic visualization. The existing tools, which are capable of highly precise analyses of high-resolution TEM images, as well as spot, disc and ring diffraction patterns, are extended to include a tool for automatically measuring TEM sample thickness using convergent beam electron diffraction in a two-beam approximation. An implementation of geometric phase analysis is newly available, employing one of the existing tools to identify parameters and indices of crystallographic planes depicted in the input image and allowing easier and more accurate analysis. The crystallographic visualization capabilities are extended as well. Along with the simulated diffraction pattern and atomic structure, a stereographic projection and inverse pole figure tool is newly offered. A new tool able to visualize the atomic structure of two different phases and their interface is also introduced.

Improvement of beamline 4B9A and results of an X-ray diffraction experiment

1998 ◽  
Vol 5 (3) ◽  
pp. 503-505
Author(s):  
D. W. Wang ◽  
H. Y. Jiang ◽  
Z. H. Wu ◽  
X. S. Wu ◽  
S. S. Jiang ◽  
...  
Keyword(s):  
Thin Film ◽  
Photon Energy ◽  
Tetragonal Symmetry ◽  
Second Phase ◽  
Diffraction Experiment ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cylindrical Mirror ◽  
Diffraction Patterns ◽  
Maximum Photon

4B9A is a focusing and monochromatic photon beam at the BSRF, which was constructed in 1990. During the second phase of the BSRF program, the surface of the cylindrical mirror has been coated with Pt, covering the original Ni, and the monochromator has been upgraded. The maximum photon energy extends to 11 keV and the intensity has increased about tenfold with respect to the previous intensity at 6 keV. Synchrotron X-ray diffraction patterns for the Hg-1223 (HgBa2Ca2Cu3O8+δ) superconducting bulk and thin film have been measured at 1.54014 Å. Results indicate that the bulk and film can be indexed as possessing tetragonal symmetry; lattice parameters a = 3.856 Å and c = 15.851 Å for the bulk Hg-1223 compound, and a = 3.8517 Å and c = 15.8511 Å for the film. Their structures are similar.

Light Optical Diffraction Studies of Macromolecular Ultrastructure

1970 ◽  
Vol 28 ◽  
pp. 258-259
Author(s):  
Glen B. Haydon
Keyword(s):  
High Resolution ◽  
Diffraction Analysis ◽  
Diffraction Pattern ◽  
Electron Micrographs ◽  
Optical Diffraction ◽  
Electron Micrograph ◽  
Its Analysis ◽  
Resolution Electron ◽  
Diffraction Patterns

Analysis of light optical diffraction patterns produced by electron micrographs can easily lead to much nonsense. Such diffraction patterns are referred to as optical transforms and are compared with transforms produced by a variety of mathematical manipulations. In the use of light optical diffraction patterns to study periodicities in macromolecular ultrastructures, a number of potential pitfalls have been rediscovered. The limitations apply to the formation of the electron micrograph as well as its analysis.(1) The high resolution electron micrograph is itself a complex diffraction pattern resulting from the specimen, its stain, and its supporting substrate. Cowley and Moodie (Proc. Phys. Soc. B, LXX 497, 1957) demonstrated changing image patterns with changes in focus. Similar defocus images have been subjected to further light optical diffraction analysis.

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