Computers and diffraction analysis

1989 ◽  
Vol 47 ◽  
pp. 44-45
Author(s):  
J. A. Eades
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Electron Diffraction ◽  
Diffraction Analysis ◽  
Electron Diffraction Analysis ◽  
Image Simulation ◽  
Correct Interpretation ◽  
High Profile ◽  
High Resolution Images ◽  
Image Simulations

For well over two decades computers have played an important role in electron microscopy; they now pervade the whole field - as indeed they do in so many other aspects of our lives. The initial use of computers was mainly for large (as it seemed then) off-line calculations for image simulations; for example, of dislocation images.Image simulation has continued to be one of the most notable uses of computers particularly since it is essential to the correct interpretation of high resolution images. In microanalysis, too, the computer has had a rather high profile. In this case because it has been a necessary part of the equipment delivered by manufacturers. By contrast the use of computers for electron diffraction analysis has been slow to prominence. This is not to say that there has been no activity, quite the contrary; however it has not had such a great impact on the field.

Atomic structure of YB56 studied by digital high-resolution electron microscopy and electron diffraction

2001 ◽  
Vol 16 (1) ◽  
pp. 101-107 ◽  
Author(s):  
Takeo Oku ◽  
Jan-Olov Bovin ◽  
Iwami Higashi ◽  
Takaho Tanaka ◽  
Yoshio Ishizawa
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Electron Diffraction ◽  
High Resolution Electron Microscopy ◽  
Charge Coupled Device ◽  
X Ray ◽  
Resolution Electron ◽  
High Resolution Images ◽  
Diffraction Patterns ◽  
Simulated Images

Atomic positions for Y atoms were determined by using high-resolution electron microscopy and electron diffraction. A slow-scan charge-coupled device camera which had high linearity and electron sensitivity was used to record high-resolution images and electron diffraction patterns digitally. Crystallographic image processing was applied for image analysis, which provided more accurate, averaged Y atom positions. In addition, atomic disordering positions in YB56 were detected from the differential images between observed and simulated images based on x-ray data, which were B24 clusters around the Y-holes. The present work indicates that the structure analysis combined with digital high-resolution electron microscopy, electron diffraction, and differential images is useful for the evaluation of atomic positions and disordering in the boron-based crystals.

The National Center for Electron Microscopy at Berkeley: An Update

1988 ◽  
Vol 46 ◽  
pp. 812-813
Author(s):  
K. H. Westmacott ◽  
U. Dahmen
Keyword(s):  
Electron Microscopy ◽  
Fourier Transforms ◽  
Microstructural Characterization ◽  
Atomic Resolution ◽  
Image Simulation ◽  
Correct Interpretation ◽  
Maximum Information ◽  
On Line ◽  
High Resolution Images ◽  
User Friendly

Since its establishment in 1984 the National Center for Electron Microscopy (NCEM) has provided a wide variety of users with advanced electron microscopy facilities for microstructural characterization. It has, in addition continued to develop and improve its resources to expand the range of features available to users.A major effort has been expended in building up a comprehensive computing facility to assist microscopists in optimizing instrument performance and extracting the maximum information from experimental data. The best currently available hardware has been assembled and a long menu of user-friendly software programs have been developed for general use. Sophisticated image simulation and image enhancement programs provide users of the Atomic Resolution Microscope all the necessary information for the correct interpretation of high resolution images. Direct links to both the ARM and the 1.5 MeV Kratos HVEM allow Fast Fourier Transforms to be performed, producing on-line diffractograms and greatly facilitating the effective and efficient use of the microscopes.

High Resolution Tem Studies of β-Alumina Type Structures

1983 ◽  
Vol 31 ◽  
Author(s):  
K. J. Morrissey ◽  
Z. Elgat ◽  
Y. Kouh ◽  
C. B. Carter
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Analytical Electron Microscopy ◽  
Image Simulation ◽  
Commercial Alumina ◽  
Transmission Electron ◽  
Analytical Electron ◽  
High Resolution Tem ◽  
High Resolution Images

ABSTRACTHigh resolution transmission electron microscopy (HRTEM) has been used to study structures found in secondphase particles in commercial alumina compacts. Analytical electron microscopy has been used to identify elements present in the particles. Computer image simulation has been used for both the structural interpretation of high resolution images and predicting the effect which the presence of other elements would have on the observed structures.

Characterization of the (0110) α-Ti/γ-TiH Interface Using High-Resolution Transmission Electron Microscopy (TEM) and Electron Energy Loss Spectroscopy (EELS)

1996 ◽  
Vol 54 ◽  
pp. 108-109
Author(s):  
M. M. Tsai ◽  
J. M. Howe
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Hydrogen Atoms ◽  
Transmission Electron ◽  
High Resolution Tem ◽  
High Resolution Images ◽  
Electron Energy Loss ◽  
Image Simulations

Precipitation of γ-TiH in α-Ti-H alloys involves a hcp → fct lattice transformation with hydrogen as an interstitial diffusing element Results obtained from a previous TEM study have shown that the lengthening rate of γ-TiH is diffusionally controlled at 25°C, and possibly interfacially controlled at temperatures of 50°C and higher. Therefore, it is essential to ascertain the presence or absence of hydrogen atoms at the interface. TEM foils from a 800 ppm wt.% Ti-H alloy were analyzed using high-resolution TEM and image simulations in order to determine the effects of hydrogen on high-resolution images of the α-Ti/γ-TiH interface, and EELS was used to determine the whether the hydnde structure was fully formed up to the interface.

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