Uranium Fixation During Uranium Migration Under an Oxidizing Condition

1994 ◽  
Vol 353 ◽  
Author(s):  
Takashi Murakami ◽  
Katsuyuki Tsuzuki ◽  
Tsutomu Sato ◽  
Hiroshi Isobe ◽  
Toshihiko Ohnuki
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Rock Specimen ◽  
Uranium Mineral ◽  
Ore Deposit ◽  
Iron Minerals ◽  
Transmission Electron ◽  
Uranium Migration ◽  
20 Nm

AbstractA rock specimen, collected downstream of the Koongarra uranium ore deposit, Australia, was examined mainly by high resolution transmission electron microscopy in order to understand the uranium fixation mechanism. Uranium was found to exist as saleeite (Mg(UO2)2(PO4)2.10H2O) microcrystals of 1 – 20 nm scattered between iron minerals (mainly goethite and hematite) of 2 – 50 nm. The microtextural relationship between saléeite and the iron minerals revealed that the iron minerals function as catalyst for the formation of saléeite. The intermediate metamict microstructures of the saléeite microcrystals are consistent with the estimated formation age of saléeite, 1 to 3 × 106 years. Uranium has been, thus, fixed as saléeite downstream as well as in the secondary ore deposit. Saléeite in the secondary ore deposit showed completely periodic to fully metamict microstructures, suggesting that saléeite, a major uranium mineral in the secondary ore deposit, probably began to form a few million years ago and continued to form for the next million years.

A High Resolution Study of G.P. Zones in Aluminum - 4.2 at % Silver

1982 ◽  
Vol 40 ◽  
pp. 722-723 ◽  
Author(s):  
R. Gronsky
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Computer Simulations ◽  
Structural Characteristics ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Resolution Study

The phenomenon of clustering in Al-Ag alloys has been extensively studied since the early work of Guinierl, wherein the pre-precipitation state was characterized as an assembly of spherical, ordered, silver-rich G.P. zones. Subsequent x-ray and TEM investigations yielded results in general agreement with this model. However, serious discrepancies were later revealed by the detailed x-ray diffraction - based computer simulations of Gragg and Cohen, i.e., the silver-rich clusters were instead octahedral in shape and fully disordered, atleast below 170°C. The object of the present investigation is to examine directly the structural characteristics of G.P. zones in Al-Ag by high resolution transmission electron microscopy.

Improved quantification of curvature in high-resolution transmission electron microscopy lattice fringe micrographs of soots

Carbon ◽  
2017 ◽  
Vol 117 ◽  
pp. 174-181 ◽  
Author(s):  
Chang’an Wang ◽  
Thomas Huddle ◽  
Chung-Hsuan Huang ◽  
Wenbo Zhu ◽  
Randy L. Vander Wal ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Lattice Fringe ◽  
Transmission Electron

Vertical self-organization of Ge1−xMnx nanocolumn multilayers grown on Ge(001) substrates

2016 ◽  
Vol 30 (20) ◽  
pp. 1650269 ◽  
Author(s):  
Thi Giang Le ◽  
Minh Tuan Dau
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Resolution ◽  
Molecular Beam Epitaxy ◽  
Elastic Constant ◽  
Structural Properties ◽  
Molecular Beam ◽  
Self Organization ◽  
Transmission Electron ◽  
2D Model

High-resolution transmission electron microscopy (HR-TEM) has been used to investigate the structural properties of GeMn/Ge nanocolumns multilayer samples grown on Ge(001) substrates by means of molecular beam epitaxy (MBE) system. Four bilayers with the spacer thickness in the range between 6 nm and 15 nm and 10 periods of bilayers of Ge[Formula: see text]Mn[Formula: see text]/Ge nanocolumn are presented. A simplified 2D model based on the theory of elastic constant interactions has been used to provide reasonable explanations to the vertical self-organization of GeMn nanocolumns in multilayers.

Sign in / Sign up

Export Citation Format

Share Document