Electron microscopy of alpha-plutonium

1986 ◽  
Vol 44 ◽  
pp. 564-565
Author(s):  
K. P. Staudhammer ◽  
K. A. Johnson ◽  
M. Stevens ◽  
W. J. Medina
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
World Wide ◽  
The Past ◽  
Thin Foils ◽  
Transmission Electron ◽  
Solid Phases ◽  
Primary Problem

During the past several decades metallurgists world-wide have sought for a reliable and reasonable method to characterize plutonium and its alloys via transmission electron microscopy. Metallurgically, plutonium (Pu) represents one of the most fascinating metals; it has six solid phases and contracts when melted.A number of workers over the years have tried to produce thin foils of plutonium, but the foils were later shown to have been completely converted to oxide. The primary problem has been in the preparation of electron transparent thin foils of a material having one of the highest atomic numbers that is highly oxidation prone, in addition to being radioactive. Advances in Pu metallography in the late 70's and early 80's produced a new series of electro-chemical thinning solutions modified for plutonium.

Phenomena Associated with Oxygen in Titanium

1967 ◽  
Vol 25 ◽  
pp. 310-311
Author(s):  
E. U. Lee ◽  
P. A. Garner ◽  
J. S. Owens
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Microscope ◽  
Microstructural Changes ◽  
Electrolytic Polishing ◽  
Interstitial Impurities ◽  
Thin Foils ◽  
Transmission Electron ◽  
Iodide Titanium ◽  
Alpha Titanium

Evidence for ordering (1-6) of interstitial impurities (O and C) has been obtained in b.c.c. metals, such as niobium and tantalum. In this paper we report the atomic and microstructural changes in an oxygenated c.p.h. metal (alpha titanium) as observed by transmission electron microscopy and diffraction.Oxygen was introduced into zone-refined iodide titanium sheets of 0.005 in. thickness in an atmosphere of oxygen and argon at 650°C, homogenized at 800°C and furnace-cooled in argon. Subsequently, thin foils were prepared by electrolytic polishing and examined in a JEM-7 electron microscope, operated at 100 KV.

On Future Directions in Pathology

1982 ◽  
Vol 40 ◽  
pp. 274-277
Author(s):  
Benjamin F. Trump ◽  
Irene K. Berezesky ◽  
Raymond T. Jones
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Clinical Pathology ◽  
Future Directions ◽  
Diagnostic Pathology ◽  
The Past ◽  
Transmission Electron ◽  
Organ Systems ◽  
The Many

The role of electron microscopy and associated techniques is assured in diagnostic pathology. At the present time, most of the progress has been made on tissues examined by transmission electron microscopy (TEM) and correlated with light microscopy (LM) and by cytochemistry using both plastic and paraffin-embedded materials. As mentioned elsewhere in this symposium, this has revolutionized many fields of pathology including diagnostic, anatomic and clinical pathology. It began with the kidney; however, it has now been extended to most other organ systems and to tumor diagnosis in general. The results of the past few years tend to indicate the future directions and needs of this expanding field. Now, in addition to routine EM, pathologists have access to the many newly developed methods and instruments mentioned below which should aid considerably not only in diagnostic pathology but in investigative pathology as well.

Simulation of three Dimensional Defect Images in Transmission Electron Microscopy

1976 ◽  
Vol 34 ◽  
pp. 470-471
Author(s):  
W. D. Cooper ◽  
C. S. Hartley ◽  
J. J. Hren
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Three Dimensional ◽  
Crystalline Lattice ◽  
Continuum Models ◽  
Thin Foils ◽  
Transmission Electron ◽  
Microscope Images ◽  
General Computer Program ◽  
General Computer

Interpretation of electron microscope images of crystalline lattice defects can be greatly aided by computer simulation of theoretical contrast from continuum models of such defects in thin foils. Several computer programs exist at the present time, but none are sufficiently general to permit their use as an aid in the identification of the range of defect types encountered in electron microscopy. This paper presents progress in the development of a more general computer program for this purpose which eliminates a number of restrictions contained in other programs. In particular, the program permits a variety of foil geometries and defect types to be simulated.The conventional approximation of non-interacting columns is employed for evaluation of the two-beam dynamical scattering equations by a piecewise solution of the Howie-Whelan equations.

scholarly journals Contributions of Electron Microscopy to Understand Secretion of Immune Mediators by Human Eosinophils

2010 ◽  
Vol 16 (6) ◽  
pp. 653-660 ◽  
Author(s):  
Rossana C.N. Melo ◽  
Ann M. Dvorak ◽  
Peter F. Weller
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Immune Responses ◽  
Innate Immune System ◽  
Innate Immune ◽  
Cell Secretion ◽  
The Past ◽  
Functional Capabilities ◽  
Immune Mediators ◽  
Transmission Electron

AbstractMechanisms governing secretion of proteins underlie the biologic activities and functions of human eosinophils, leukocytes of the innate immune system, involved in allergic, inflammatory, and immunoregulatory responses. In response to varied stimuli, eosinophils are recruited from the circulation into inflammatory foci, where they modulate immune responses through the release of granule-derived products. Transmission electron microscopy (TEM) is the only technique that can clearly identify and distinguish between different modes of cell secretion. In this review, we highlight the advances in understanding mechanisms of eosinophil secretion, based on TEM findings, that have been made over the past years and that have provided unprecedented insights into the functional capabilities of these cells.

scholarly journals Electron Microscopy Investigation of Magnetization Process in Thin Foils and Nanostructures

2007 ◽  
Vol 1026 ◽  
Author(s):  
Pascale Bayle-Guillemaud ◽  
Aurelien Masseboeuf ◽  
Fabien Cheynis ◽  
Jean-Christophe Toussaint ◽  
Olivier Fruchart ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Magnetic Anisotropy ◽  
Magnetic Induction ◽  
Perpendicular Magnetic Anisotropy ◽  
In Situ Observation ◽  
Magnetic Imaging ◽  
Thin Foils ◽  
Transmission Electron

AbstractThis paper presents investigations of magnetization configuration evolution during in-situ magnetic processes in materials exhibiting planar and perpendicular magnetic anisotropy. Transmission electron microscopy has been used to perform magnetic imaging. Fresnel contrasts in Lorentz Transmission Electron Microscopy (LTEM) and phase retrieval methods such as Transport of Intensity Equation (TIE) solving or electron holography have been implemented. These techniques are sensitive to magnetic induction perpendicular to the electron beam and can give access to a spatially resolved (resolution better than 10 nm) mapping of magnetic induction distribution and could be extended to dynamical studies during in-situ observation. Thin foils of FePd alloys with a strong perpendicular magnetic anisotropy (PMA) and self-assembled Fe dots are presented. Both are studied during magnetization processes exhibiting the capacities of in-situ magnetic imaging in a TEM.

Nano-Thermometry: Transmission Electron Microscopy of Femtosecond Laser Irradiated Co/Si Multilayer Thin Foils

2005 ◽  
Vol 899 ◽  
Author(s):  
Yoosuf Picard ◽  
Steven M. Yalisove
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Amorphous Silicon ◽  
Heat Dissipation ◽  
Crystalline Silicon ◽  
Pulse Length ◽  
Multilayer Systems ◽  
Hole Edge ◽  
Thin Foils ◽  
Transmission Electron

AbstractPre-thinned foils composed of amorphous silicon and polycrystalline cobalt were irradiated using femtosecond pulse-length lasers at fluences sufficient for ablation (material removal). The resultant ablated hole and surrounding vicinity was studied using transmission electron microscopy to determine modifications to the structure. Evidence of cobalt silicide formation was observed within a 3 micron radius of the laser hole edge by use of selected area electron diffraction (SAED). In addition, elongated grains of crystalline silicon was observed within 500 nm of the laser hole edge, indicating melting of the amorphous silicon and heat dissipation slow enough to allow recyrstallization. This initial work demonstrates the use of pre-designed nanostructured multilayer systems as a method for nanoscale profiling of heat dissipation following pulsed laser irradiation.

The Dislocation Patterns in Deformed Metals: Dislocation Densities, Distributions and Related Misorientations

2007 ◽  
Vol 550 ◽  
pp. 193-198
Author(s):  
Edgar F. Rauch ◽  
G. Shigesato
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Transmission Electron Microscopy ◽  
Dislocation Substructure ◽  
Metals And Alloys ◽  
The Past ◽  
Transmission Electron ◽  
Dislocation Densities ◽  
Broad Variety ◽  
The Relationship

The dislocation substructure that appears in deformed metals and alloys have been extensively investigated in the past by transmission electron microscopy (TEM). They are known to form a broad variety of microstructures. These substructures are characterized by three main parameters, namely the density of the dislocations that are trapped in the tangles, their degree of patterning and the misorientation between the cells. The aim of the present work is to investigate the relationship between these features and the mechanical properties of the material.

The Initial Stages of Oxide Film Formation on Copper and Some Copper Alloys

CORROSION ◽  
1969 ◽  
Vol 25 (7) ◽  
pp. 291-299 ◽  
Author(s):  
M. D. SANDERSON ◽  
J. C. SCULLY
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Electron Diffraction ◽  
Film Formation ◽  
Copper Alloys ◽  
Amorphous Layer ◽  
Oxide Formation ◽  
Thin Foils ◽  
Transmission Electron ◽  
Crystallographic Planes

Abstract The initial stages of oxide formation on thin foils of copper, Cu-2.5Al-2.5Si, and Cu-7.5Al-2Si alloys in moist atmospheres of oxygen and sulfur dioxide have been studied by transmission electron microscopy and electron diffraction over the temperature range 200-380 C (392-716 F). On the Cu-2.5Al-2.5Si alloy grain boundaries and twin boundaries are preferential sites for oxide nucleation. On the Cu-7.5Al-2Si alloy no preferential sites are observed. The relative reactivities of different crystallographic planes are the same for the alloys as for the metal. On oxidized thin foils a prenucleation thermal pitting phenomenon has been observed at temperatures very much lower than the thermal pitting observed by other workers. Oxide nuclei have been observed to form on a thin amorphous layer of oxide even when there is no metal directly underneath. These results are discussed with reference to current theories on the initial stages of oxide formation. It is concluded that in the prenucleation stage the metal surface is covered with a highly mobile layer of cations and anions.

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