High-resolution electron microscopy and image simulations of coincidence site patterns due to overlap of variants in Au4Mn

1984 ◽  
Vol 40 (a1) ◽  
pp. C389-C389
Author(s):  
W. Coene ◽  
D. Van Dyck ◽  
G. Van Tendeloo ◽  
J. Van Landuyt
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Resolution Electron ◽  
Image Simulations

Atomic chemistry by HREM and image simulations?

1986 ◽  
Vol 44 ◽  
pp. 828-829
Author(s):  
J.M. Howe ◽  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Structural Information ◽  
High Resolution Electron Microscopy ◽  
Resolution Electron ◽  
Image Simulations

The technique of high-resolution electron microscopy (HREM) is invaluable to the materials scientist because it allows examination of microstructural features at levels of resolution that are unobtainable by most other methods. Although the structural information which can be determined by HREM and accompanying image simulations has been well documented in the literature, there have only been a few cases where this technique has been used to reveal the chemistry of individual columns or planes of atoms, as occur in segregated and ordered materials.

High resolution electron microscopy of bismuth and thallium superconductors

1988 ◽  
Vol 46 ◽  
pp. 868-869
Author(s):  
J. P. Zhang ◽  
D. J. Li ◽  
H. Shibahara ◽  
L. D. Marks
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Shear Wave ◽  
High Resolution Electron Microscopy ◽  
Double Layers ◽  
Resolution Electron ◽  
New Frontier ◽  
Image Simulations

A new frontier has opened up in the field of superconductivity with the very recent discovery of compounds of bismuth and thallium which appear to superconduct above 100 K. Both of these compounds appear to be perovskite derivatives with intergrowth of the basic perovskite with bismuth double-layers and perhaps thallium double layers. The structure of these compounds, however, is not as yet completely established, particularly the thallium material which to date has only been produced in very small quantities due to the toxic nature of thallium.We have very recently been studying both the bismuth and thallium superconductors by high resolution electron microscopy. The bismuth material appears to be an intergrowth of a five layer perovskite with a buckling of the structure along the b axis (see Figure 1) which preliminary image simulations suggest is in the form of a shear wave of amplitude in the region of 0.25 Angstroms.

Hrem Investigation of Ai-MgO Interface

1993 ◽  
Vol 319 ◽  
Author(s):  
W.P. Vellinga ◽  
M. Verwerft ◽  
J.Th.M. De Hosson ◽  
Tj. Hibma
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Resolution Electron ◽  
Metal Ceramic ◽  
Mgo Substrate ◽  
Image Simulations

AbstractA metal-ceramic interface was produced by depositing Al on a {100} MgO substrate in a MBE system. The interface was studied with High Resolution Electron Microscopy. Results of some image simulations are shown, raising the question if effects of ionicity and charging should be taken into account.

High-Resolution Electron Microscopy of Dislocation Cores in NiAl

1998 ◽  
Vol 552 ◽  
Author(s):  
D. Stöckle ◽  
W. Sigle ◽  
A. Seeger
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Peierls Stress ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Stress Components ◽  
Vector Distribution ◽  
Image Simulations ◽  
High Resolution Electron Micrographs

ABSTRACTThe atomic structure of dislocation cores in NiAl is studied by high-resolution transmission electron microscopy (HRTEM) and molecular dynamics (MD) calculations. Results are presented on dislocations with Burgers vectors b=a<100> and a<111>. A comparison with HRTEM image simulations indicates that the core of a 45° a <100> dislocation consists of Al atoms. The Burgers vector distribution shows a width of 2.2b. This corresponds very closely to MD results and is consistent with the relatively low Peierls stress of this dislocation. By detailed image analysis the angular dependence of the shear stress components of the dislocation are made visible. MD results obtained from 45° dislocations with opposite screw components suggest, that the helicity of the screw component might be discernible from high-resolution electron micrographs. A a<111> dislocation with <110> line direction is shown which exhibits a rather wide dissociation, probably into two a/2<111> partials.

High-resolution electron microscopy of dislocations of MgO

1994 ◽  
Vol 9 (11) ◽  
pp. 2953-2958 ◽  
Author(s):  
J. Ohta ◽  
K. Suzuki ◽  
T. Suzuki
Keyword(s):  
Electron Microscopy ◽  
Plastic Deformation ◽  
High Resolution ◽  
Ion Irradiation ◽  
High Resolution Electron Microscopy ◽  
Burgers Vector ◽  
Resolution Electron ◽  
Lattice Images ◽  
Simulated Images ◽  
Image Simulations

Dislocations in MgO introduced by ion irradiation and by plastic deformation are observed by HREM. Depending on the Burgers vector and the dislocation character, various types of lattice images are obtained. Image simulations are performed for the inclination of dislocations, as well as for dissociated dislocations. A comparison of observed and simulated images shows that inclination of nondissociated dislocations makes them appear as if they were dissociated; in reality a/2(110) dislocations in MgO are not dissociated.

scholarly journals Comparisons Of Observed And Simulated Atomic Structures Of Pd/NiO Heterophase Interfaces

1992 ◽  
Vol 295 ◽  
Author(s):  
M. I. Buckett ◽  
J. P. Shaffer ◽  
Karl L. Merkle
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Rigid Body ◽  
Atomic Structure ◽  
High Resolution Electron Microscopy ◽  
Boundary Plane ◽  
Misfit Dislocations ◽  
Atomic Structures ◽  
Resolution Electron ◽  
Image Simulations

AbstractHigh-resolution electron microscopy (HREM) and image simulations using the multislice algorithm have been used to study the atomic structure of a Pd/NiO (111) interface in an intemally oxidized sample. Samples prepared in this way result in cube-on-cube oriented or twin-related precipitates whose (111) interfaces exhibit a contrast modulation along the boundary plane in HREM images. Previous studies have reported that the observed structural period of this modulation corresponds qualitatively to the expected spacing if the boundary was composed of a network of misfit dislocations. In this study, rigid models of the (111) interface as viewed from the [110] direction were simulated using the EMS suite of programs. The questions we address are: (1) whether the terminating plane on the oxide side is made up of a Ni or an 0 layer, and (2) whether a rigid body translation normal to the interface exists. Finally, the results of the simulations are compared and contrasted to through-focal experimental images to investigate the origin of the contrast modulations and their possible relation to the extent of the misfit localization in these systems.

Structural analysis of the surface-layer protein of spirillum serpens by high-resolution electron microscopy

1983 ◽  
Vol 41 ◽  
pp. 738-739
Author(s):  
W. H. Wu ◽  
R. M. Glaeser
Keyword(s):  
Electron Microscopy ◽  
Surface Layer ◽  
Structural Analysis ◽  
High Resolution ◽  
Low Dose ◽  
High Resolution Electron Microscopy ◽  
Optical Diffraction ◽  
Surface Layer Protein ◽  
Morphological Unit ◽  
Resolution Electron

Spirillum serpens possesses a surface layer protein which exhibits a regular hexagonal packing of the morphological subunits. A morphological model of the structure of the protein has been proposed at a resolution of about 25 Å, in which the morphological unit might be described as having the appearance of a flared-out, hollow cylinder with six ÅspokesÅ at the flared end. In order to understand the detailed association of the macromolecules, it is necessary to do a high resolution structural analysis. Large, single layered arrays of the surface layer protein have been obtained for this purpose by means of extensive heating in high CaCl2, a procedure derived from that of Buckmire and Murray. Low dose, low temperature electron microscopy has been applied to the large arrays.As a first step, the samples were negatively stained with neutralized phosphotungstic acid, and the specimens were imaged at 40,000 magnification by use of a high resolution cold stage on a JE0L 100B. Low dose images were recorded with exposures of 7-9 electrons/Å2. The micrographs obtained (Fig. 1) were examined by use of optical diffraction (Fig. 2) to tell what areas were especially well ordered.

Electron microscopy of rabbit FC crystals

1983 ◽  
Vol 41 ◽  
pp. 730-731
Author(s):  
Robert A. Grant ◽  
Laura L. Degn ◽  
Wah Chiu ◽  
John Robinson
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Molecular Replacement ◽  
X Ray ◽  
X Ray Crystallography ◽  
Resolution Electron ◽  
Replacement Technique ◽  
Hydrated Crystal ◽  
Molecular Structure Analysis

Proteolytic digestion of the immunoglobulin IgG with papain cleaves the molecule into an antigen binding fragment, Fab, and a compliment binding fragment, Fc. Structures of intact immunoglobulin, Fab and Fc from various sources have been solved by X-ray crystallography. Rabbit Fc can be crystallized as thin platelets suitable for high resolution electron microscopy. The structure of rabbit Fc can be expected to be similar to the known structure of human Fc, making it an ideal specimen for comparing the X-ray and electron crystallographic techniques and for the application of the molecular replacement technique to electron crystallography. Thin protein crystals embedded in ice diffract to high resolution. A low resolution image of a frozen, hydrated crystal can be expected to have a better contrast than a glucose embedded crystal due to the larger density difference between protein and ice compared to protein and glucose. For these reasons we are using an ice embedding technique to prepare the rabbit Fc crystals for molecular structure analysis by electron microscopy.

High resolution electron microscopy of lanthanum phosphate crystals

1978 ◽  
Vol 36 (1) ◽  
pp. 274-275
Author(s):  
J. C. Wheatley ◽  
J. M. Cowley
Keyword(s):  
Electron Microscopy ◽  
Catalytic Activity ◽  
High Resolution ◽  
Petroleum Industry ◽  
High Resolution Electron Microscopy ◽  
Lanthanum Phosphate ◽  
Good Catalyst ◽  
Resolution Electron ◽  
Good Catalytic Activity ◽  
Physical And Chemical

Rare-earth phosphates are of particular interest because of their catalytic properties associated with the hydrolysis of many aromatic chlorides in the petroleum industry. Lanthanum phosphates (LaPO4) which have been doped with small amounts of copper have shown increased catalytic activity (1). However the physical and chemical characteristics of the samples leading to good catalytic activity are not known.Many catalysts are amorphous and thus do not easily lend themselves to methods of investigation which would include electron microscopy. However, the LaPO4, crystals are quite suitable samples for high resolution techniques.The samples used were obtained from William L. Kehl of Gulf Research and Development Company. The electron microscopy was carried out on a JEOL JEM-100B which had been modified for high resolution microscopy (2). Standard high resolution techniques were employed. Three different sample types were observed: 669A-1-5-7 (poor catalyst), H-L-2 (good catalyst) and 27-011 (good catalyst).

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