scholarly journals Crystal Structure of the ZrO Phase at Zirconium/Zirconium Oxide Interfaces

2014 ◽  
Vol 17 (2) ◽  
pp. 211-215 ◽  
Author(s):  
Rebecca J. Nicholls ◽  
Na Ni ◽  
Sergio Lozano-Perez ◽  
Andrew London ◽  
David W. McComb ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Zirconium Oxide ◽  
Oxide Interfaces

scholarly journals Crystal Structure of Anhydrous Zirconium Oxide Sulfate

1988 ◽  
Vol 96 (1118) ◽  
pp. 980-984 ◽  
Author(s):  
Chunting LI ◽  
Keiji DAIMON ◽  
Yoshio MURASE ◽  
Etsuro KATO
Keyword(s):  
Crystal Structure ◽  
Zirconium Oxide ◽  
Oxide Sulfate

Influence of crystal structure on the light scatter of zirconium oxide films

1997 ◽  
Vol 36 (7) ◽  
pp. 1626 ◽  
Author(s):  
David Reicher ◽  
Kenneth Jungling
Keyword(s):  
Crystal Structure ◽  
Zirconium Oxide ◽  
Oxide Films ◽  
Light Scatter

Zirconium oxide crystal phase: The role of the pH and time to attain the final pH for precipitation of the hydrous oxide

1988 ◽  
Vol 3 (4) ◽  
pp. 787-797 ◽  
Author(s):  
Ram Srinivasan ◽  
Mary B. Harris ◽  
Stanley F. Simpson ◽  
Robert J. De Angelis ◽  
Burtron H. Davis
Keyword(s):  
Crystal Structure ◽  
Tetragonal Phase ◽  
Zirconium Oxide ◽  
Dominant Role ◽  
Crystal Phase ◽  
Dominant Factor ◽  
Hydrous Oxide ◽  
Supernatant Liquid ◽  
Oxide Crystal

Precipitated hydrous zirconium oxide can be calcined to produce either a monoclinic or tetragonal product. It has been observed that the time taken to attain the final pH of the solution in contact with the precipitate plays a dominant role in determining the crystal structure of the zirconium oxide after calcination at 500 °C. The dependence of crystal structure on the rate of precipitation is observed only in the pH range 7–11. Rapid precipitation in this pH range yields predominately monoclinic zirconia, whereas slow (8 h) precipitation produces the tetragonal phase. At pH of approximately 13.0, only the tetragonal phase is formed from both slowly and rapidly precipitated hydrous oxide. The present results, together with earlier results, show that both the pH of the supernatant liquid and the time taken to attain this pH play dominant roles in determining the crystal structure of zirconia that is formed after calcination of the hydrous oxide. The factors that determine the crystal phase are therefore imparted in a mechanism of precipitation that depends upon the pH, and it is inferred that it is the hydroxyl concentration that is the dominant factor.

Crystal structure of hafnia–zirconia mixtures obtained by calcination of hydrous oxide prepared by precipitation

1988 ◽  
Vol 3 (3) ◽  
pp. 561-562 ◽  
Author(s):  
Li-Min Tau ◽  
Ram Srinivasan ◽  
Robert J. De Angelis ◽  
Tim Pinder ◽  
Burtron H. Davis
Keyword(s):  
Crystal Structure ◽  
Tetragonal Phase ◽  
Zirconium Oxide ◽  
Monoclinic Phase ◽  
Dominant Role ◽  
Hydrous Oxide ◽  
Hydrous Zirconium Oxide ◽  
Low Concentrations ◽  
Definition Of ◽  
Hydrous Zirconium

The pH of the solution in contact with a hydrous zirconium oxide plays a dominant role in determining the crystal phase, tetragonal or monoclinic, in the calcined material. The substitution of low concentrations of hafnium for zirconium destabilizes the tetragonal phase so that only the monoclinic phase is formed; the amount of Hf required for destabilization depends upon the pH used for the preparation of the hydrous oxide. While this study has defined a phenomenon, the results do not permit a definition of the mechanism for it.

Synthesis, Characterization, and X-ray Crystal Structure of a Gallium Monohydroxide and a Hetero-bimetallic Gallium Zirconium Oxide

2006 ◽  
Vol 45 (3) ◽  
pp. 949-951 ◽  
Author(s):  
Sanjay Singh ◽  
Vojtech Jancik ◽  
Herbert W. Roesky ◽  
Regine Herbst-Irmer
Keyword(s):  
Crystal Structure ◽  
Zirconium Oxide ◽  
X Ray

Resolving Crystallites in Zirconium Oxide Films

1969 ◽  
Vol 27 ◽  
pp. 140-141
Author(s):  
R.A. Ploc
Keyword(s):  
Electron Microscope ◽  
Inelastic Scattering ◽  
Zirconium Oxide ◽  
Oxide Films ◽  
Optic Axis ◽  
Objective Lens ◽  
Microscope Objective ◽  
Linear Optic ◽  
A Current ◽  
Microscope Objective Lens

The optic axis of an electron microscope objective lens is usually assumed to be straight and co-linear with the mechanical center. No reason exists to assume such perfection and, indeed, simple reasoning suggests that it is a complicated curve. A current centered objective lens with a non-linear optic axis when used in conjunction with other lenses, leads to serious image errors if the nature of the specimen is such as to produce intense inelastic scattering.

Crystal Structure Determination of Glycerol-Containing Lipids from Electron Diffraction Data. Use of Analog Compounds Based upon Configurational Isomers of Cyclopentane-1, 2, 3-TRIOL

1977 ◽  
Vol 35 ◽  
pp. 24-25
Author(s):  
Douglas L. Dorset ◽  
Anthony J. Hancock
Keyword(s):  
Crystal Structure ◽  
Electron Diffraction ◽  
Diffraction Data ◽  
Structure Determination ◽  
Crystal Surface ◽  
Coherent Scattering ◽  
Crystal Structure Determination ◽  
Electron Diffraction Data ◽  
Polar Group ◽  
Axis Orientation

Lipids containing long polymethylene chains were among the first compounds subjected to electron diffraction structure analysis. It was only recently realized, however, that various distortions of thin lipid microcrystal plates, e.g. bends, polar group and methyl end plane disorders, etc. (1-3), restrict coherent scattering to the methylene subcell alone, particularly if undistorted molecular layers have well-defined end planes. Thus, ab initio crystal structure determination on a given single uncharacterized natural lipid using electron diffraction data can only hope to identify the subcell packing and the chain axis orientation with respect to the crystal surface. In lipids based on glycerol, for example, conformations of long chains and polar groups about the C-C bonds of this moiety still would remain unknown.One possible means of surmounting this difficulty is to investigate structural analogs of the material of interest in conjunction with the natural compound itself. Suitable analogs to the glycerol lipids are compounds based on the three configurational isomers of cyclopentane-1,2,3-triol shown in Fig. 1, in which three rotameric forms of the natural glycerol derivatives are fixed by the ring structure (4-7).

Spherulitic crystal growth in the prodissoconch larval of Crassostrea virginica

1983 ◽  
Vol 41 ◽  
pp. 518-519
Author(s):  
George G. Cocks ◽  
Louis Leibovitz ◽  
DoSuk D. Lee
Keyword(s):  
Crystal Structure ◽  
Crassostrea Virginica ◽  
Crystal Orientation ◽  
Developmental Changes ◽  
Gastrula Stage ◽  
Orthorhombic Crystal ◽  
Orthorhombic Crystal Structure ◽  
Stages Of Growth ◽  
Early Stages ◽  
Initial Deposition

Our understanding of the structure and the formation of inorganic minerals in the bivalve shells has been considerably advanced by the use of electron microscope. However, very little is known about the ultrastructure of valves in the larval stage of the oysters. The present study examines the developmental changes which occur between the time of conception to the early stages of Dissoconch in the Crassostrea virginica(Gmelin), focusing on the initial deposition of inorganic crystals by the oysters.The spawning was induced by elevating the temperature of the seawater where the adult oysters were conditioned. The eggs and sperm were collected separately, then immediately mixed for the fertilizations to occur. Fertilized animals were kept in the incubator where various stages of development were stopped and observed. The detailed analysis of the early stages of growth showed that CaCO3 crystals(aragonite), with orthorhombic crystal structure, are deposited as early as gastrula stage(Figuresla-b). The next stage in development, the prodissoconch, revealed that the crystal orientation is in the form of spherulites.

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