FEM and FIM Study of Reaction Zones on Platinum

1997 ◽  
Vol 62 (2) ◽  
pp. 213-217
Author(s):  
Zlatko Knor ◽  
Jan Plšek ◽  
Luboš Dvořák
Keyword(s):  
Temperature Field ◽  
Low Temperature ◽  
Single Crystals ◽  
Room Temperature ◽  
Effect Of Temperature ◽  
Surface Anisotropy ◽  
Initial Shape ◽  
Reaction Zones

The initial shape of the reaction zones for the interaction of hydrogen and oxygen on the surfaces of the single crystals of platinum in FEM and FIM devices is discussed in connection with the effect of temperature and surface anisotropy. Interaction of the (H2 + O2) mixture has been studied at room temperature and the results were confronted with the interaction of hydrogen and preadsorbed oxygen at low temperature and with the anisotropy of the low-temperature field-corrosion of platinum.

Spin-Lattice Coupling and Peculiarities of Magnetic Behavior of Ferrimagnetic Ludwigites Mn0.52+M1.52+Mn3+BO5(M=Cu, Ni)

2015 ◽  
Vol 233-234 ◽  
pp. 133-136 ◽  
Author(s):  
Leonard Bezmaternykh ◽  
Evgeniya Moshkina ◽  
Evgeniy Eremin ◽  
Maxim Molokeev ◽  
Nikita Volkov ◽  
...  
Keyword(s):  
Temperature Field ◽  
Low Temperature ◽  
Magnetic Anisotropy ◽  
Single Crystals ◽  
Magnetic Behavior ◽  
Temperature Hysteresis ◽  
Spin Lattice ◽  
Field Magnetization ◽  
Lattice Coupling

Temperature-field and orientational magnetization dependences of single crystals were measured. Both samples demonstrate significant field-depending temperature hysteresis and low-temperature counter field magnetization. The correlation of orientational dependences of these effects and magnetic anisotropy is analyzed; the role of spin-lattice interactions is discussed.

Effect of Temperature on Crater Formation and Ejecta Composition in Aluminum Alloy Targets

2012 ◽  
Vol 706-709 ◽  
pp. 768-773
Author(s):  
Masahiro Nishida ◽  
Koichi Hayashi ◽  
Junichi Nakagawa ◽  
Yoshitaka Ito
Keyword(s):  
Aluminum Alloy ◽  
High Temperature ◽  
Low Temperature ◽  
Room Temperature ◽  
Effect Of Temperature ◽  
Crater Formation ◽  
Influence Of Temperature ◽  
Gas Gun ◽  
Influence Of Temperature On ◽  
Increasing Temperature

The influence of temperature on crater formation and ejecta composition in thick aluminum alloy targets were investigated for impact velocities ranging from approximately 1.5 to 3.5 km/s using a two-stage light-gas gun. The diameter and depth of the crater increased with increasing temperature. The ejecta size at low temperature was slightly smaller than that at high temperature and room temperature. Temperature did not affect the size ratio of ejecta. The scatter diameter of the ejecta at high temperature was slightly smaller than those at low and room temperatures.

Dislocation Structures in Deformed Tin Single Crystals

1982 ◽  
Vol 40 ◽  
pp. 468-469
Author(s):  
G.W. Qiao
Keyword(s):  
Plastic Deformation ◽  
Electron Beam ◽  
Low Temperature ◽  
Single Crystals ◽  
Current Density ◽  
Perchloric Acid ◽  
Room Temperature ◽  
High Mobility ◽  
Tetragonal Structure ◽  
Methanol Mixture

Although β-tin is a familiar metal with tetragonal structure, its dislocation structures in bulk specimens after plastic deformation or irradiation have not been reported with observations by TEM probably because of difficulties in preparing specimens and the relatively high mobility of dislocations under electron beam illumination at room temperature (T/Tm~0.7). It proved possible to prepare specimens of β-tin for TEM observation using low temperature, double-jet electro-polishing techniques using 8% perchloric acid in methanol mixture at -30 °C under 80 volts and a typical current density of 0.7 Acm-2.

Solution-Based Processing of Sc2O3 Nanopowders Yielding Transparent Ceramics

2004 ◽  
Vol 19 (3) ◽  
pp. 733-736 ◽  
Author(s):  
Ji-Guang Li ◽  
Takayasu Ikegami ◽  
Toshiyuki Mori
Keyword(s):  
Low Temperature ◽  
Single Crystals ◽  
Ammonium Sulfate ◽  
Room Temperature ◽  
Wavelength Region ◽  
Transparent Ceramics ◽  
Vacuum Sintering ◽  
Visible Wavelength ◽  
Mixed Solutions

A basic sulfate precursor [Sc(OH)SO4·2H2O] for well-sinterable Sc2O3 powders was precipitated from mixed solutions of scandium nitrate [Sc(NO3)3] and ammonium sulfate [(NH4)2SO4] at room temperature and which was subsequently converted to Sc2O3 via dehydroxylization and desulfurization at temperatures ≥900 °C. With the reactive powders synthesized in this work, polycrystalline Sc2O3 ceramics showing high inline transmittances of approximately 70% in the visible wavelength region (corresponding to ∼90% of the theoretical value of single crystals) have been fabricated via vacuum sintering at a relatively low temperature of 1700 °C.

Photoluminescence Study of p-ZnGeP2 Crystals

1996 ◽  
Vol 450 ◽  
Author(s):  
Yurri V. Rud ◽  
Vasilii Yu ◽  
M. C. Ohmer ◽  
P. G. Shunemann
Keyword(s):  
Low Temperature ◽  
Single Crystals ◽  
Room Temperature ◽  
Directed Crystallization ◽  
Acceptor Pair ◽  
Long Wavelength ◽  
Donor Acceptor ◽  
Donor Acceptor Pair ◽  
Nonlinear Devices ◽  
Conversion Efficiencies

ABSTRACTPhotoluminescence (PL) steady-state spectra of p-ZnGeP2 (ZGP) single crystals grown by high- and low-temperature directed crystallization have been investigated. It is determined that the long-wavelength component PL with a maximum in the interval 1.2–1.5 eV for different crystals quenched in the temperature range 77–300 K. The long-wavelength component PL are due to donor-acceptor pair transitions. At room temperature the short-wavelength PL with a maximum near 1.85 eV becomes the determining component. The nature of this band discussed. The use of low-temperature directed crystallization reduces the concentration of lattice defects in ZGP single crystals and opens up the new possibilities for increasing the conversion efficiencies of nonlinear devices.

Structure of solid chlorine at 1.45 GPa

2019 ◽  
Vol 234 (4) ◽  
pp. 277-280 ◽  
Author(s):  
Laura Henry ◽  
Volodymyr Svitlyk ◽  
Gaston Garbarino ◽  
David Sifre ◽  
Mohamed Mezouar
Keyword(s):  
High Pressure ◽  
Low Temperature ◽  
Single Crystal ◽  
Single Crystals ◽  
Room Temperature ◽  
Diamond Anvil Cell ◽  
Ambient Pressure ◽  
Orthorhombic Symmetry ◽  
Single Crystal Diffraction ◽  
Diamond Anvil

Abstract Single crystals of solid chlorine (Cl2) were synthesized at room temperature and high pressure (HP, P=1.45 GPa) in a diamond anvil cell (DAC). At these conditions Cl2 adapts the same structure as its corresponding low-temperature (LT) ambient pressure modification (T<172 K), as concluded from HP single crystal diffraction experiments. Namely, it crystallizes in an orthorhombic symmetry (Cmce spacegroup) with Cl2 molecules forming monolayers parallel to the bc plane and this structure is preserved up to at least 64 GPa. The pressure of 1.45 GPa is to be considered as a solidification point of liquid Cl2 at room temperature.

Slip Transition in [001] Oriented Nial at High Temperatures

1990 ◽  
Vol 213 ◽  
Author(s):  
J.T. Kim ◽  
R. Gibala
Keyword(s):  
Transition Temperature ◽  
Single Crystals ◽  
High Temperatures ◽  
Room Temperature ◽  
Effect Of Temperature ◽  
Slip Direction ◽  
Annealing Temperatures ◽  
The Stability ◽  
Slip Transition

ABSTRACTThe present work was undertaken to understand the transition in slip direction In [001] oriented NiAl as a function of temperature. Single crystals of [001] NiAl were deformed at room temperature to produce <111> dislocations and were subsequently annealed at various temperatures in order to see the effect of temperature on the stability of the <111> dislocation. These results were compared with corresponding dislocation substructures of specimens deformed directly at high temperatures. During annealing <111> dislocations are dissociated into <001>+<110> dislocations at 773–923 K. It is also observed that <111> dislocations can be dissociated into <001>+<110> dislocations during deformation in the vicinity of the transition temperature of around 773 K. The quantitative details of these changes depend on deformation or annealing temperatures.

Low Temperature Transport Properties of Ru2Si3 Single Crystals

1995 ◽  
Vol 402 ◽  
Author(s):  
U. Gottlieb ◽  
R. Madar ◽  
O. Laborde
Keyword(s):  
Low Temperature ◽  
Transport Properties ◽  
Single Crystals ◽  
Room Temperature ◽  
Scaling Law ◽  
Band Model ◽  
Metal Insulator ◽  
Typical Behaviour ◽  
Two Band Model ◽  
Resistivity Behaviour

AbstractWe present here low temperature transport properties of Ru2Si3 single crystals. Below room temperature the resistivity behaviour of this material is extrinsic. The Hall coefficient is positive down to about 10 K and the becomes negative below. We explain this crossover with a two band model. At very low T, the magnetoresistance of our crystals shows the typical behaviour for a doped semiconductor on the metallic side of the metal-insulator transition and can be described by a scaling law characteristic for weak localisation with strong electronelectron interactions.

Dislocation structures around SiO2 Particles in aged Cu-Cr-SiO2

1978 ◽  
Vol 36 (1) ◽  
pp. 594-595
Author(s):  
N.J. Long ◽  
M.H. Loretto ◽  
C.H. Lloyd
Keyword(s):  
Flow Stress ◽  
Single Crystals ◽  
Room Temperature ◽  
Thin Foil ◽  
Age Hardening ◽  
Dispersion Strengthening ◽  
Accurate Picture ◽  
The Matrix ◽  
Very High ◽  
Good Agreement

IntroductionThere have been several t.e.m. studies (1,2,3,4) of the dislocation arrangements in the matrix and around the particles in dispersion strengthened single crystals deformed in single slip. Good agreement has been obtained in general between the observed structures and the various theories for the flow stress and work hardening of this class of alloy. There has been though some difficulty in obtaining an accurate picture of these arrangements in the case when the obstacles are large (of the order of several 1000's Å). This is due to both the physical loss of dislocations from the thin foil in its preparation and to rearrangement of the structure on unloading and standing at room temperature under the influence of the very high localised stresses in the vicinity of the particles (2,3).This contribution presents part of a study of the Cu-Cr-SiO2 system where age hardening from the Cu-Cr and dispersion strengthening from Cu-Sio2 is combined.

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