Computer generation and automatic plotting of perfect and twinned electron diffraction patterns for cubic crystal structures

Although a few X-ray crystal structures of normal-chain esters of long chain acids and short chain alcohols have been carried out, attention has been paid mostly to the long-spacings of waxes synthesized from longer chain alcohols. We have been interested in exploring the crystal structures of the more symmetric waxes via electron diffraction studies.Myristyl stearate thin crystals were epitaxially grown on benzoic acid by the method developed by Wittmann et al. Some samples with or without the presence of the nucleating substrates were annealed at 45°C for 4 hours on a Met tier FP82 hot stage. The thin crystals before or after annealing were examined with a JEOL JEM-100CX electron microscope operated at 100 kV, and selected area electron diffraction patterns from [100] and [110] directions were recorded on Kodak DEF-5 X-ray film. The calibration of the camera length was carried out with a gold Debye-Scherrer diagram. Models of molecular packing were scanned with an Optronics P-1000, and their Fourier transforms were calculated with a program in IMAGIC.

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Classification of crystal structures using electron diffraction patterns with a deep convolutional neural network

RSC Advances ◽

10.1039/d1ra07156d ◽

2021 ◽

Vol 11 (61) ◽

pp. 38307-38315

Author(s):

Moonsoo Ra ◽

Younggun Boo ◽

Jae Min Jeong ◽

Jargalsaikhan Batts-Etseg ◽

Jinha Jeong ◽

...

Keyword(s):

Neural Network ◽

Electron Diffraction ◽

Convolutional Neural Network ◽

Crystal Structures ◽

Network Architecture ◽

Deep Convolutional Neural Network ◽

Neural Network Architecture ◽

Selected Area Electron Diffraction ◽

Diffraction Patterns

The off-the-shelf deep convolutional neural network architecture, ResNet, could classify the space group of materials with cubic crystal structures with the prediction accuracy of 92.607%, using the selected area electron diffraction patterns.

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Pollutant Identification by Selected Area Electron Diffraction

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100052675 ◽

1974 ◽

Vol 32 ◽

pp. 532-533

Author(s):

R. E. Ferrell ◽

G. G. Paulson ◽

C. W. Walker

Keyword(s):

Thermal Treatment ◽

Electron Diffraction ◽

Sample Preparation ◽

Crystal Structures ◽

Water Samples ◽

Environmental Samples ◽

Short Review ◽

Selected Area Electron Diffraction ◽

Multiple Component

Selected area electron diffraction (SAD) has been used successfully to determine crystal structures, identify traces of minerals in rocks, and characterize the phases formed during thermal treatment of micron-sized particles. There is an increased interest in the method because it has the potential capability of identifying micron-sized pollutants in air and water samples. This paper is a short review of the theory behind SAD and a discussion of the sample preparation employed for the analysis of multiple component environmental samples.

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Computer Indexing of Electron Diffraction Patterns Including the Effects of Lattice Symmetry

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010007775x ◽

1977 ◽

Vol 35 ◽

pp. 22-23

Author(s):

J. S. Lally ◽

R. J. Lee

Keyword(s):

Electron Diffraction ◽

Zone Axis ◽

Crystal Thickness ◽

Double Diffraction ◽

Automated Method ◽

Lattice Symmetry ◽

Intensity Calculations ◽

Unknown Structure ◽

Diffraction Patterns ◽

Orientation Parameters

In the 50 year period since the discovery of electron diffraction from crystals there has been much theoretical effort devoted to the calculation of diffracted intensities as a function of crystal thickness, orientation, and structure. However, in many applications of electron diffraction what is required is a simple identification of an unknown structure when some of the shape and orientation parameters required for intensity calculations are not known. In these circumstances an automated method is needed to solve diffraction patterns obtained near crystal zone axis directions that includes the effects of systematic absences of reflections due to lattice symmetry effects and additional reflections due to double diffraction processes.Two programs have been developed to enable relatively inexperienced microscopists to identify unknown crystals from diffraction patterns. Before indexing any given electron diffraction pattern, a set of possible crystal structures must be selected for comparison against the unknown.

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Electron-diffraction studies in synthetic polymer materials

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100075579 ◽

1983 ◽

Vol 41 ◽

pp. 362-365

Author(s):

D.T. Grubb

Keyword(s):

Electron Diffraction ◽

Synthetic Polymer ◽

Polymer Materials ◽

Crystallographic Structure ◽

High Dose ◽

Electron Dose ◽

Dose Rates ◽

First Case ◽

Diffraction Patterns ◽

The Many

Diffraction studies in polymeric and other beam sensitive materials may bring to mind the many experiments where diffracted intensity has been used as a measure of the electron dose required to destroy fine structure in the TEM. But this paper is concerned with a range of cases where the diffraction pattern itself contains the important information.In the first case, electron diffraction from paraffins, degraded polyethylene and polyethylene single crystals, all the samples are highly ordered, and their crystallographic structure is well known. The diffraction patterns fade on irradiation and may also change considerably in a-spacing, increasing the unit cell volume on irradiation. The effect is large and continuous far C94H190 paraffin and for PE, while for shorter chains to C 28H58 the change is less, levelling off at high dose, Fig.l. It is also found that the change in a-spacing increases at higher dose rates and at higher irradiation temperatures.

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An Interactive Minicomputer Program for the Indexing and Simulation of Electron Diffraction Patterns

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100092670 ◽

1976 ◽

Vol 34 ◽

pp. 542-543

Author(s):

R.P. Goehner ◽

W.T. Hatfield ◽

Prakash Rao

Keyword(s):

Electron Diffraction ◽

Real Time ◽

Pattern Analysis ◽

Flow Diagram ◽

Hard Copy ◽

Time Analysis ◽

Real Time Analysis ◽

Transmission Electron ◽

One Step ◽

Diffraction Patterns

Computer programs are now available in various laboratories for the indexing and simulation of transmission electron diffraction patterns. Although these programs address themselves to the solution of various aspects of the indexing and simulation process, the ultimate goal is to perform real time diffraction pattern analysis directly off of the imaging screen of the transmission electron microscope. The program to be described in this paper represents one step prior to real time analysis. It involves the combination of two programs, described in an earlier paper(l), into a single program for use on an interactive basis with a minicomputer. In our case, the minicomputer is an INTERDATA 70 equipped with a Tektronix 4010-1 graphical display terminal and hard copy unit.A simplified flow diagram of the combined program, written in Fortran IV, is shown in Figure 1. It consists of two programs INDEX and TEDP which index and simulate electron diffraction patterns respectively. The user has the option of choosing either the indexing or simulating aspects of the combined program.

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