scholarly journals Temperature dependence of density and thermal expansion of oxides of praseodymium and dysprosium in the temperature range 300 to 1000 K

2020 ◽  
Vol 1495 ◽  
pp. 012032
Author(s):  
M. RangaRao ◽  
N. GopiKrishna ◽  
S Chandra lingam
Keyword(s):  
Thermal Expansion ◽  
Temperature Dependence ◽  
Temperature Range

scholarly journals Studies on Thermophysical Properties of CaO and MgO by γ-Ray Attenuation

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
A. S. Madhusudhan Rao ◽  
K. Narender
Keyword(s):  
Thermal Expansion ◽  
Temperature Dependence ◽  
Thermophysical Properties ◽  
Linear Thermal Expansion ◽  
Temperature Dependent ◽  
Degree Polynomial ◽  
Attenuation Coefficients ◽  
Temperature Range ◽  
Thermal Expansion Coefficients ◽  
Expansion Coefficients

The study on temperature dependent γ-ray attenuation and thermophysical properties of CaO and MgO has been carried out in the temperature range 300 K–1250 K using different energies of γ-beam, namely, Am (0.0595 MeV), Cs (0.66 MeV), and Co (1.173 MeV and 1.332 MeV) on γ-ray densitometer fabricated in our laboratory. The linear attenuation coefficients (μl) for the pellets of CaO and MgO as a function of temperature have been determined using γ-beam of different energies. The coefficients of temperature dependence of density have been reported. The variation of density and linear thermal expansion of CaO and MgO in the temperature range of 300 K–1250 K has been studied and compared with the results available in the literature. The temperature dependence of linear attenuation coefficients, density, and thermal expansion has been represented by second degree polynomial. Volume thermal expansion coefficients have been reported.

scholarly journals Thermal expansion of nickel-chromium ChS88U alloy at high temperatures

2021 ◽  
Vol 2057 (1) ◽  
pp. 012116
Author(s):  
Yu M Kozlovskii ◽  
S V Stankus
Keyword(s):  
Thermal Expansion ◽  
Phase Transformation ◽  
Temperature Dependence ◽  
High Temperatures ◽  
Reference Values ◽  
Experimental Results ◽  
Temperature Range ◽  
Nickel Chromium ◽  
Estimated Error

Abstract The experimental results of the study of thermal expansion of nickel-chrome alloy in the temperature range of 293.15–1400 K are presented. The phase transformation of the first kind in the alloy is observed. The estimated error of the obtained data is 3%. Approximation equations and a table of reference values for the temperature dependence of the studied properties are obtained.

Thermal expansion of decagonal Al70.7Co13.3Ni16.0 in the temperature range 15–300 K

2001 ◽  
Vol 216 (12) ◽  
Author(s):  
A. Kupsch ◽  
D. C. Meyer ◽  
P. Gille ◽  
P. Paufler
Keyword(s):  
Thermal Expansion ◽  
Temperature Dependence ◽  
Lattice Parameters ◽  
Temperature Range

AbstractThe temperature dependence of lattice parameters

THERMAL EXPANSION, GRUENEISEN PARAMETER, AND TEMPERATURE DEPENDENCE OF LATTICE VIBRATION FREQUENCIES OF ALUMINUM OXIDE

1965 ◽  
Vol 43 (4) ◽  
pp. 523-531 ◽  
Author(s):  
Alois Schauer
Keyword(s):  
Thermal Expansion ◽  
Aluminum Oxide ◽  
Temperature Dependence ◽  
Lattice Vibration ◽  
Linear Thermal Expansion ◽  
Vibration Frequencies ◽  
Polycrystalline Aluminum ◽  
Interferometric Method ◽  
Temperature Range ◽  
Wide Range

The linear thermal expansion coefficient of polycrystalline aluminum oxide has been measured in the temperature range from 100 °K to 1 500 °K by an interferometric method. The interferometer used is capable of giving high accuracy over a wide range of temperatures, and is described in some detail. The Grueneisen parameter of aluminum oxide is calculated and found to be 1.35 ± 0.05 over the whole temperature range. There is no significant change, such as might be expected from theory, of the Grueneisen parameter around 0.2 × Debye temperature. Based on the formulae given in an earlier publication, the temperature dependence of lattice vibration frequencies of aluminum oxide is calculated.

X-ray diffractometry of AlGaAs/GaAs superlattices and GaAs in the temperature range 5–295 K

1989 ◽  
Vol 22 (4) ◽  
pp. 372-375 ◽  
Author(s):  
G. Clec'h ◽  
G. Calvarin ◽  
P. Auvray ◽  
M. Baudet
Keyword(s):  
Thermal Expansion ◽  
Temperature Dependence ◽  
Low Temperatures ◽  
X Ray ◽  
Lattice Constants ◽  
Temperature Range ◽  
Thermal Expansion Coefficients ◽  
Gaas Substrates ◽  
Expansion Coefficients ◽  
Tetrahedrally Bonded

The temperature dependence of the lattice constants of Al x Ga1 − x As/GaAs superlattices MBE-grown on (001) oriented GaAs substrates was determined by X-ray diffractometry. The thermal expansion coefficients of these materials become negative at low temperatures, like that of GaAs and other tetrahedrally bonded covalent solids. The temperature dependence of the stress in these structures was also studied; although its value increases as temperature decreases, strain remains elastic down to 5 K.

The influence of the sapphire substrate on the temperature dependence of the GaN bandgap

1999 ◽  
Vol 572 ◽  
Author(s):  
Joachim Krüiger ◽  
Noad Shapiro ◽  
Sudhir Subramanya ◽  
Yihwan Kim ◽  
Henrik Siegle ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Temperature Dependence ◽  
Sapphire Substrate ◽  
Measured Temperature ◽  
Temperature Range ◽  
Thermal Expansion Coefficients ◽  
Small Influence ◽  
Expansion Coefficients ◽  
The Difference ◽  
First Time

ABSTRACTThis paper analyses the influence of the sapphire substrate on stress in GaN epilayers in the temperature range between 4K and 600K. Removal of the substrate by a laser assisted liftoff technique allows, for the first time, to distinguish between stress and other material specific temperature dependencies. In contrast to the prevailing assumption in the literature, that the difference in the thermal expansion coefficients is the main cause for stress it is found that the substrate has a rather small influence in the examined temperature range. The measured temperature dependence of stress is in contradiction to the published values for the thermal expansion coefficients for sapphire and GaN.

Specific features of the temperature dependence of tryptophan fluorescence lifetime in the temperature range of −170–20 °C

2020 ◽  
Vol 393 ◽  
pp. 112435
Author(s):  
Peter P. Knox ◽  
Vladimir V. Gorokhov ◽  
Boris N. Korvatovsky ◽  
Nadezhda P. Grishanova ◽  
Sergey N. Goryachev ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Fluorescence Lifetime ◽  
Tryptophan Fluorescence ◽  
Temperature Range

A neutron powder diffraction determination of the thermal expansion tensor of crocoite (PbCrO4) between 60 K and 290 K

1996 ◽  
Vol 60 (403) ◽  
pp. 963-972 ◽  
Author(s):  
Kevin S. Knight
Keyword(s):  
Thermal Expansion ◽  
Temperature Dependence ◽  
Powder Diffraction ◽  
Maximum Expansion ◽  
Lattice Constants ◽  
Thermal Expansion Tensor ◽  
Diffraction Determination ◽  
Line Passing ◽  
Neutron Time

AbstractThe thermal expansion tensor of crocoite has been determined from high-resolution neutron time-of-flight powder diffraction data. The temperature dependence of the lattice constants between 4.5 K and 290 K have been fitted to a quasi-harmonic Einstein model, and the temperature dependence of the thermal expansion tensor has been calculated for 60 K ≤ T ≤ 290 K. The magnitudes of the principal expansivities and their orientation exhibit saturation behaviour for temperatures above 300 K. The predicted saturated expansion coefficients are α11 = 33.1(1) × 10−6K−1, α22 = 15.72(3) × 10−6K−1, α33 = 3.36(1) × 10−6K−1, with α22 parallel to b and α11 lying at an angle of −37.86(5)° to c for the P21/n setting of the crystal structure. The direction of maximum expansion is approximately parallel to both and the least-squares line passing through the projection of the chromium atoms on (010). The direction of minimum expansion lies approximately parallel to [101]. No evidence was found for either a structural or magnetic phase transition between 4.5 K and 300 K.

Phonon Decay in GaN and AlN and Self-Heating in III-N Devices

2006 ◽  
Vol 955 ◽  
Author(s):  
Mark Holtz ◽  
D. Y. Song ◽  
S. A. Nikishin ◽  
V. Soukhoveev ◽  
A. Usikov ◽  
...  
Keyword(s):  
Thermal Expansion ◽  
Temperature Dependence ◽  
High Quality ◽  
Self Heating ◽  
Phonon Emission ◽  
Decay Properties ◽  
Phonon Properties

ABSTRACTWe report studies of the temperature dependence of Raman lines in high quality GaN and AlN. The temperature dependence of the phonon energies and linewidths are used to produce consistent phonon decay properties of zone center optic phonons. In GaN we observe the E22 phonon to decay into three phonons, while the A1(LO) phonon is well described according to the so-called Ridley process – one TO and one LA phonon. For AlN the E22 phonon decays by two phonon emission and the A1(LO) line also exhibits a dependence consistent with the Ridley process. Along with the phonon decay processes, it is important in each case to take into account the contribution of the thermal expansion, including the temperature dependence, to describe observed temperature shifts in the phonon properties.

Sign in / Sign up

Export Citation Format

Share Document