scholarly journals Simulated Image Maps for Use in Experimental High-Resolution Electron Microscopy

1989 ◽  
Vol 159 ◽  
Author(s):  
Michael A. O'Keefe ◽  
Ulrich Dahmen ◽  
Crispin J.D. Hetherington
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Perfect Crystal ◽  
Phase Object ◽  
Simulated Image ◽  
Transmission Electron ◽  
Resolution Electron ◽  
High Resolution Images ◽  
Imaging Conditions

ABSTRACTA “map” of all possible high-resolution images may be simulated for a crystalline specimen in a chosen orientation for any particular transmission electron microscope (HRTEM). These maps are useful during experimental high-resolution electron microscopy and make it possible to locate optimum imaging conditions even for foil thicknesses beyond the weak-phase object limit. Although defects such as grain boundaries are not generally periodic, image maps of perfect crystal can be used to optimize defect contrast during operation of the microscope by reference to the image of the perfect crystal neighboring the defect.

High-Resolution Electron Microscopy of Interfaces In Ain - Braze Metal Alloy Systems

1989 ◽  
Vol 159 ◽  
Author(s):  
A. H. Carim
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Nitride Phase ◽  
Orientation Relationships ◽  
Transmission Electron ◽  
Resolution Electron ◽  
High Resolution Images ◽  
Lattice Planes ◽  
Specific Orientation

ABSTRACTThe microstructural aspects of active brazing of AIN with a Ag-Cu-Ti alloy have been investigated. A series of reaction product layers are formed. TiN is produced in contact with the polycrystalline, bulk AIN. High-resolution transmission electron microscopy and microdiffraction demonstrate that some of the TiN grains at the interface display specific orientation relationships with respect to the adjoining AIN crystallites. As has sometimes been observed in studies of epitaxy in other systems, these relationships are not necessarily those that provide the minimum geometrical mismatch between one or more sets of lattice planes. Farther from the substrate, an fl-type nitride phase with composition (Ti,Cu,Al)6N occurs as a reaction product. High-resolution images confirm the absence of amorphous or crystalline intervening phases at the TiN-ŋ interface and at ŋ grain boundaries.

High Resolution Transmission Electron Microscopy of an automobile catalytic converter

1990 ◽  
Vol 48 (4) ◽  
pp. 242-243
Author(s):  
Jan-Olle Malm ◽  
Jan-Olov Bovin
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Catalytic Converter ◽  
Active Material ◽  
Image Intensifier ◽  
High Resolution Electron Microscopy ◽  
Detailed Knowledge ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Atomic Surface

Understanding of catalytic processes requires detailed knowledge of the catalyst. As heterogeneous catalysis is a surface phenomena the understanding of the atomic surface structure of both the active material and the support material is of utmost importance. This work is a high resolution electron microscopy (HREM) study of different phases found in a used automobile catalytic converter.The high resolution micrographs were obtained with a JEM-4000EX working with a structural resolution better than 0.17 nm and equipped with a Gatan 622 TV-camera with an image intensifier. Some work (e.g. EDS-analysis and diffraction) was done with a JEM-2000FX equipped with a Link AN10000 EDX spectrometer. The catalytic converter in this study has been used under normal driving conditions for several years and has also been poisoned by using leaded fuel. To prepare the sample, parts of the monolith were crushed, dispersed in methanol and a drop of the dispersion was placed on the holey carbon grid.

Interpretation of the Contrast of High-Resolution Electron Microscopy Images of Ni4Mo by Means of Simulated Image Maps

1990 ◽  
Vol 48 (1) ◽  
pp. 28-29
Author(s):  
A. Thust ◽  
K. Urban
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Antiphase Boundary ◽  
High Resolution Electron Microscopy ◽  
Foil Thickness ◽  
Order Structure ◽  
Simulated Image ◽  
Resolution Electron ◽  
Fcc Lattice ◽  
Direct Interpretation

The alloy of composition Ni4Mo develops, at temperatures below 860 °C, an ordered Dla-structure which is based on the fcc-lattice. This alloy has been widely investigated with respect to its physical properties and its ordering behaviour. High resolution studies are rare and concentrated mainly on its short-range order structure. The aim of the present work was to develop a detailed understanding of image contrast and to apply the results to antiphase-boundary studies in ordered Ni4Mo by means of a JEOL 4000 EX electron microscope.In high-resolution electron microscopy, depending on defocus and foil thickness, a large variety of different images is obtained. Only a few of these allow a direct interpretation concerning the location and the type of the atoms. By computing a through-focus/through-thickness map (TFTT map) before starting experimental work it is possible to determine the proper conditions at which images can be obtained which are closely related to the projected potential.

Structure of InAs Quantum Dots in Si Matrix Investigated by High Resolution Electron Microscopy

1999 ◽  
Vol 571 ◽  
Author(s):  
N. D. Zakharov ◽  
P. Werner ◽  
V. M. Ustinov ◽  
A.R. Kovsh ◽  
G. E. Cirlin ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Critical Thickness ◽  
High Resolution Electron Microscopy ◽  
Geometrical Parameters ◽  
Inas Quantum Dots ◽  
Temperature Growth ◽  
Transmission Electron ◽  
Resolution Electron

ABSTRACTQuantum dot structures containing 2 and 7 layers of small coherent InAs clusters embedded into a Si single crystal matrix were grown by MBE. The structure of these clusters was investigated by high resolution transmission electron microscopy. The crystallographic quality of the structure severely depends on the substrate temperature, growth sequence, and the geometrical parameters of the sample. The investigation demonstrates that Si can incorporate a limited volume of InAs in a form of small coherent clusters about 3 nm in diameter. If the deposited InAs layer exceeds a critical thickness, large dislocated InAs precipitates are formed during Si overgrowth accumulating the excess of InAs.

Silicon-Sapphire Interface: A High Resolution Electron Microscopy Study

1980 ◽  
Vol 2 ◽  
Author(s):  
Fernando A. Ponce
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Silicon Layer ◽  
High Resolution Electron Microscopy ◽  
Microscopy Study ◽  
Electron Microscopy Study ◽  
Resolution Limit ◽  
High Concentration ◽  
Transmission Electron ◽  
Resolution Electron

ABSTRACTThe structure of the silicon-sapphire interface of CVD silicon on a (1102) sapphire substrate has been studied in crøss section by high resolution transmission electron microscopy. Multibeam images of the interface region have been obtained where both the silicon and sapphire lattices are directly resolved. The interface is observed to be planar and abrupt to the instrument resolution limit of 3 Å. No interfacial phase is evident. Defects are inhomogeneously distributed at the interface: relatively defect-free regions are observed in the silicon layer in addition to regions with high concentration of defects.

HIGH RESOLUTION ELECTRON MICROSCOPY OF THE HIGH Tc SUPERCONDUCTOR Bi2Sr2CaCu2O8+δ

1988 ◽  
Vol 02 (06) ◽  
pp. 835-839 ◽  
Author(s):  
M. HERVIEU ◽  
B. DOMENGES ◽  
C. MICHEL ◽  
B. RAVEAU
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Electron Diffraction Study ◽  
High Resolution Electron Microscopy ◽  
Basic Structure ◽  
Tetragonal Symmetry ◽  
High Tc ◽  
Resolution Electron ◽  
High Resolution Images ◽  
New Superconductor

The new superconductor Bi 2 Sr 2 CaCu 2 O 8+δ with T c ranging from 80 to 105K, was studied by electron microscopy. The electron diffraction study shows a pseudo-tetragonal symmetry with a≈b≈5.4 Å and c≈30.7 Å and satellites along a, which settle in an incommensurate way. The high resolution images agree with the proposed basic structure. The stacking of the ( BiO y)2 and [ Sr 2 CaCu 2 O 6] layers is quite regular, with only some defects corresponding to c≈24 Å. The lamellar character of the oxide results in splitting and bending of the crystals.

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.

High Resolution Electron Microscopy Observations About The Interface Structure In A Ti/TiN Multilayer Material

1991 ◽  
Vol 238 ◽  
Author(s):  
X. G. Ning ◽  
L. P. Guo ◽  
R. F. Huang ◽  
J. Gong ◽  
B. H. Yu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Orientation Relationship ◽  
High Resolution Electron Microscopy ◽  
Interface Structure ◽  
Multilayer Material ◽  
Transition Layers ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Specific Orientation

ABSTRACTThe interface structure in a Ti/TiN multilayer material has been investigated by high resolution transmission electron microscopy (HRTEM). It was shown that the α-Ti and β-TiN layers consisted of many cylindrical crystals growing along the close packed directions normal to the surface of a stainless steel. There existed specific orientation relationship at the Ti/TiN interfaces without transition layers: (111)TiN ‖ (001)Ti, [110]TiN ‖ [100]Ti. However there was no such orientation relationship at the Ti/TiN interfaces with TixN (x >1) transition layers.

Combined Use of Small Angle Neutron Scattering (Sans) and (Conventional and High Resolution) Electron Microscopy for the Characterization of Early Stages of Ordering and Phase Separation in Ni-Ti

1986 ◽  
Vol 82 ◽  
Author(s):  
A. Cerri ◽  
R. Schmelczer ◽  
P. Schwander ◽  
G. Kostorz ◽  
A.F. Wright
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
High Resolution Electron Microscopy ◽  
Tem Analysis ◽  
Zone Formation ◽  
Early Stages ◽  
Transmission Electron ◽  
Resolution Electron ◽  
Combined Use ◽  
Integrated Intensity

ABSTRACTThe decomposition of Ni ∼ 11.5 at.% Ti single crystals was studied for an ageing temperature of 540°C. In this alloy, coherent ordered zones of γ′-Ni3Ti (Cu3Au structure) are formed prior to the stable n precipitates. The early stages of zone formation were investigated by in-beam SANS and transmission electron microscopy (TEM). Electron diffraction, high resolution electron microscopy, TEM analysis of dislocation arrangements in samples deformed after ageing and X-ray measurements of the integrated intensity at L12 superstructure positions show that ordered regions already appear in quenched samples, whereas compositional changes, as determined by SANS measurements, occur only upon ageing.

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