Structural Aspects of NaV 2O 5 under High Pressure

1999 ◽  
Vol 68 (10) ◽  
pp. 3286-3291 ◽  
Author(s):  
Kenji Ohwada ◽  
Hironori Nakao ◽  
Yasuhiko Fujii ◽  
Masahiko Isobe ◽  
Yutaka Ueda
Keyword(s):  
High Pressure ◽  
Structural Aspects

Deformation Induced Percolating Porosity In High Pressure Torsioned (HPT) Copper

2011 ◽  
Vol 702-703 ◽  
pp. 105-108 ◽  
Author(s):  
Matthias Wegner ◽  
Jörn Leuthold ◽  
Sergiy V. Divinski ◽  
Daria Setman ◽  
Michael Zehetbauer ◽  
...  
Keyword(s):  
High Pressure ◽  
Impurity Concentration ◽  
High Pressure Torsion ◽  
Applied Pressure ◽  
Processing Parameters ◽  
Tracer Method ◽  
Radiotracer Technique ◽  
Degree Of Deformation ◽  
Radio Tracer ◽  
Structural Aspects

Copper of different purity levels (4N, 5N) produced by High Pressure Torsion (HPT) with varying processing parameters is investigated utilizing the radiotracer technique. While the degree of deformation is constant, the effect of the applied quasi-hydrostatic pressure and of the impurity concentration on the as deformed samples is analysed. By applying the radio tracer method micro structural aspects are revealed that are not easily accessible by conventional methods. The measurements indicate the formation of a percolating porosity during the HPT process as a function of the applied pressure and (although less pronounced) of the impurity concentration.

Structural aspects of solid iodine associated with metallization and molecular dissociation under high pressure

1982 ◽  
Vol 26 (2) ◽  
pp. 998-1004 ◽  
Author(s):  
K. Takemura ◽  
S. Minomura ◽  
O. Shimomura ◽  
Y. Fujii ◽  
J. D. Axe
Keyword(s):  
High Pressure ◽  
Molecular Dissociation ◽  
Structural Aspects

High-Pressure X-Ray Diffraction Studies of Elastic Anomalies in Superlattice

1991 ◽  
Vol 231 ◽  
Author(s):  
Y. Fujii ◽  
Y. Ohishi ◽  
H. Konishi ◽  
N. Nakayama ◽  
T. Shinjo
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Diamond Anvil Cell ◽  
Orthorhombic Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Layer Stacking ◽  
Diamond Anvil ◽  
Elastic Anomalies ◽  
Structural Aspects

AbstractThis paper has made an overview on elastic and structural aspects of three distinct superlattices under hydrostatic pressure up to about 8GPa, which were studied by our unique x-ray diffraction technique incorporated with a diamond-anvil cell. They are metallic fcc/fcc Au/Ni, bcc/fcc Mo/Ni, and semiconductive epitaxially-grown PbSe/SnSe superlattices. In their layer-stacking direction, both metallic superlattices show the supermodulus behavior while the semiconductive one doesn't. However, its pressure-driven cubic-to-orthorhombic phase transition, successively taking place in the SnSe and PbSe layers, has been found to significantly shift by stress due to its epitaxial growth.

Structural Aspects of Deformational Amorphization of Ti50Ni25Cu25 Crystalline Alloy under High Pressure Torsion

2018 ◽  
Vol 60 (6) ◽  
pp. 1168-1172 ◽  
Author(s):  
R. V. Sundeev ◽  
A. V. Shalimova ◽  
A. M. Glezer ◽  
E. A. Pechina ◽  
M. V. Gorshenkov
Keyword(s):  
High Pressure ◽  
High Pressure Torsion ◽  
Crystalline Alloy ◽  
Structural Aspects

First Principles Investigations on the Controversy of Structural Phase Transitions in Thorium Dialuminide under Pressure

2021 ◽  
Author(s):  
Ashok Kumar Verma ◽  
Paritosh Modak
Keyword(s):  
Crystal Structure ◽  
Phase Transition ◽  
High Pressure ◽  
Phase Transitions ◽  
First Principles ◽  
Structural Phase ◽  
First Principles Calculations ◽  
Structural Phase Transitions ◽  
Structural Aspects

We study the high pressure structural aspects of thorium dialuminide, ThAl2, by performing evolutionary crystal structure searches and first principles calculations. We predict a phase transition from the ambient AlB2-type...

High-pressure freezing of cells in suspension for low-voltage scanning electron microscopy (LVSEM)

1991 ◽  
Vol 49 ◽  
pp. 64-65
Author(s):  
Marek Malecki ◽  
James Pawley ◽  
Hans Ris
Keyword(s):  
Electron Microscopy ◽  
High Pressure ◽  
Low Voltage ◽  
Culture Media ◽  
Cell Structure ◽  
Freeze Substitution ◽  
Ice Crystal ◽  
High Pressure Freezing ◽  
Cell Culture Media ◽  
Voltage Scanning

The ultrastructure of cells suspended in physiological fluids or cell culture media can only be studied if the living processes are stopped while the cells remain in suspension. Attachment of living cells to carrier surfaces to facilitate further processing for electron microscopy produces a rapid reorganization of cell structure eradicating most traces of the structures present when the cells were in suspension. The structure of cells in suspension can be immobilized by either chemical fixation or, much faster, by rapid freezing (cryo-immobilization). The fixation speed is particularly important in studies of cell surface reorganization over time. High pressure freezing provides conditions where specimens up to 500μm thick can be frozen in milliseconds without ice crystal damage. This volume is sufficient for cells to remain in suspension until frozen. However, special procedures are needed to assure that the unattached cells are not lost during subsequent processing for LVSEM or HVEM using freeze-substitution or freeze drying. We recently developed such a procedure.

Structural aspects of osmoregulation in porphyra

1978 ◽  
Vol 36 (2) ◽  
pp. 412-413
Author(s):  
C. Wiencke ◽  
A. Lauchli
Keyword(s):  
Culture Medium ◽  
Point Of View ◽  
Chemical Fixation ◽  
Cellular Organization ◽  
Osmotic Adaptation ◽  
Osmotic Balance ◽  
Activity Of Enzymes ◽  
Osmotic Agents ◽  
Vacuolar System ◽  
Structural Aspects

Osmoregulatory mechanisms in algae were investigated mainly from a physiological point of view (KAUSS 1977, HELLEBUST 1976). In Porphyra two osmotic agents, i. e. floridoside/isofloridoside (KAUSS 1968) and certain ions, such as K+ and Na+(EPPLEY et al. 1960) are considered for osmotic balance. Accumulations of ions (particularly Na+) in the cytoplasm during osmotic adaptation is improbable, because the activity of enzymes is generally inhibited by high ionic concentrations (FLOWERS et al. 1977).The cellular organization of Porphyra was studied with special emphasis on the development of the vacuolar system under different hyperosmotic conditions. Porphyra was cultivated at various strengths of the culture medium ASP 12 (PROVASOLI 1961) ranging from normal to 6 times concentrated (6x) culture medium. Por electron microscopy freeze fracturing was used (specimens fixed in 2% glutaraldehyde and incubated in 30% glycerol, preparation in a BALZERS BA 360 M apparatus), because chemical fixation gave poor results.

Prolonged Fixation Studies For Spaceflight

1973 ◽  
Vol 31 ◽  
pp. 332-333
Author(s):  
Robert Corbett ◽  
Delbert E. Philpott ◽  
Sam Black
Keyword(s):  
High Pressure ◽  
Living Systems ◽  
Prolonged Storage ◽  
Time Intervals ◽  
Early Signs ◽  
Large Numbers

Observation of subtle or early signs of change in spaceflight induced alterations on living systems require precise methods of sampling. In-flight analysis would be preferable but constraints of time, equipment, personnel and cost dictate the necessity for prolonged storage before retrieval. Because of this, various tissues have been stored in fixatives and combinations of fixatives and observed at various time intervals. High pressure and the effect of buffer alone have also been tried.Of the various tissues embedded, muscle, cartilage and liver, liver has been the most extensively studied because it contains large numbers of organelles common to all tissues (Fig. 1).

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