A Raman Scattering Study of the Temperature Dependence of Boroxol Ring Clusters in B2 O3-GeO2 and B2 O3-GeO2-SiO2 Glasses.

1984 ◽  
Vol 41 ◽  
Author(s):  
I. N. Chakraborty ◽  
R. A. Condrate
Keyword(s):  
Raman Scattering ◽  
Temperature Dependence ◽  
Room Temperature ◽  
Arrhenius Plot ◽  
Scattering Data ◽  
Intensity Data ◽  
Kcal Mole ◽  
Raman Study ◽  
Scattering Study ◽  
Composition Ring

AbstractThis Raman study indicates that the boroxol ring concentrations for glasses in the B2 O3-GeO2 and B2 O3-GeO2-SiO2 systems are dependent upon temperature and composition. Ring breakage and formation occur well below Tg. An Arrhenius plot of intensity data for borogermanate g glass indicates that the heat of ring rupture is ca. 7.7 Kcal/mole. The boroxol ring concentrations in various glasses were also investigated at room temperature after various heat treatments. The structural interpretation from Raman scattering data was compared with that from IR data.

A Study of the Temperature-Dependence of Low-Frequency, Raman-Active Phonons in Stage-2 Graphite-K and Graphite-Rb Intercalation Compounds

1982 ◽  
Vol 20 ◽  
Author(s):  
J. Giergiel ◽  
P. C. Eklund ◽  
R. Al-Jishi ◽  
G. Dresselhaus
Keyword(s):  
Phase Transitions ◽  
Raman Scattering ◽  
Temperature Dependence ◽  
Raman Spectra ◽  
Lattice Dynamics ◽  
Low Frequency ◽  
Frequency Region ◽  
Intercalation Compounds ◽  
Dynamics Model ◽  
Scattering Study

ABSTRACTWe report results from a Raman scattering study of stage 2 Graphite-Rb and Graphite-K in the low frequency region (ω < 150 cm-1) as a function of temperature (80K < T < 300K). Four features are seen in the 80K spectra and are interpreted in terms of a Born– von Kármán lattice dynamics model. The temperature-dependence of the Raman spectra is discussed in connection with reported phase transitions in stage 2 alkalimetal graphite compounds.

scholarly journals Coherence lifetime broadened optical transitions in a 2 atom diameter HgTe nanowire: a temperature dependent resonance Raman study

RSC Advances ◽  
2016 ◽  
Vol 6 (98) ◽  
pp. 95387-95395 ◽  
Author(s):  
Joseph H. Spencer ◽  
David C. Smith ◽  
Liam P. McDonnell ◽  
Jeremy Sloan ◽  
Reza J. Kashtiban
Keyword(s):  
Raman Scattering ◽  
Temperature Dependence ◽  
Resonance Raman ◽  
Strong Temperature Dependence ◽  
Optical Transitions ◽  
Temperature Dependent ◽  
Raman Study ◽  
Electronic Coherence ◽  
Excitonic Effects

The paper sets out the role of electronic coherence in the strong temperature dependence of the intensity of Raman scattering from two atom diameter HgTe nanowires. It argues the behavior is likely common in extreme nanowires, and possibly due to excitonic effects.

Raman Scattering Study of H2O2-Etched Zn0.1Cd0.9Te Surfaces

1996 ◽  
Vol 450 ◽  
Author(s):  
Brajesh K. Rai ◽  
R. S. Katiyar ◽  
K. -T. Chen ◽  
H. Chen ◽  
A. Burger
Keyword(s):  
Raman Scattering ◽  
Quantum Confinement ◽  
Laser Power ◽  
Peak Position ◽  
Downward Shift ◽  
Te Precipitates ◽  
Raman Modes ◽  
Raman Study ◽  
Scattering Study ◽  
High Irradiation

ABSTRACTRaman study of as-grown and H2O2-etched surfaces of Zn0.1Cd0.9 Te single crystal has been performed. A distribution of Te precipitates on the surface of as-grown ZCT, which increases after etching, has been encountered. With high irradiation powers, due to the oxidation of the surfaces, new bands of TeO32− are evolved. A downward shift in the peak position, as well as a halfwidth broadening, of all Raman modes has been observed with increasing laser power. The phenomenon, due to the formation of insulating oxide of tellurium in a dispersion of Te precipitates and vice-versa, has been attributed to the quantum confinement of phonons.

Size-effect Stabilization of the Low-T Ferroelectric Phase in Nanocrystalline WO3

1994 ◽  
Vol 332 ◽  
Author(s):  
Xiang-Xin Bi ◽  
W. T. Lee ◽  
Kai-An Wang ◽  
D. F. Collins ◽  
S. Bandow ◽  
...  
Keyword(s):  
Particle Size ◽  
Raman Scattering ◽  
Size Effect ◽  
Room Temperature ◽  
Ferroelectric Phase ◽  
Average Particle Size ◽  
Average Particle ◽  
Narrow Size Distribution ◽  
Experimental Conditions ◽  
Scattering Study

ABSTRACTUsing a CO2 laser to drive the pyrolysis of W(CO)6 and O2, we have synthesized nanocrystalline WO3-x particles. These nanopowders are found to exhibit a narrow size distribution with an average particle size produced in the range 5 to 10 nm, depending on the experimental conditions. Typical production rates are ∼ 2 g/h. Results from a Raman scattering study on WO3 nanopowder samples annealed in O2 indicate that a smaller particle size appears to stabilize the low-T ferroelectric phase ( < -40 °C) at room temperature.

ABOUT HEAT CAPACITY OF TITANIUM CARBIDE TiCx

2019 ◽  
pp. 56-66
Author(s):  
I. Khidirov ◽  
V. V. Getmanskiy ◽  
A. S. Parpiev ◽  
Sh. A. Makhmudov
Keyword(s):  
Heat Capacity ◽  
High Temperature ◽  
Titanium Carbide ◽  
Temperature Dependence ◽  
Carbon Concentration ◽  
Room Temperature ◽  
Thermodynamic Characteristics ◽  
Liquid Nitrogen Temperature ◽  
Analysis Data ◽  
Thermal Excitation

This work relates to the field of thermophysical parameters of refractory interstitial alloys. The isochoric heat capacity of cubic titanium carbide TiCx has been calculated within the Debye approximation in the carbon concentration  range x = 0.70–0.97 at room temperature (300 K) and at liquid nitrogen temperature (80 K) through the Debye temperature established on the basis of neutron diffraction analysis data. It has been found out that at room temperature with decrease of carbon concentration the heat capacity significantly increases from 29.40 J/mol·K to 34.20 J/mol·K, and at T = 80 K – from 3.08 J/mol·K to 8.20 J/mol·K. The work analyzes the literature data and gives the results of the evaluation of the high-temperature dependence of the heat capacity СV of the cubic titanium carbide TiC0.97 based on the data of neutron structural analysis. It has been proposed to amend in the Neumann–Kopp formula to describe the high-temperature dependence of the titanium carbide heat capacity. After the amendment, the Neumann–Kopp formula describes the results of well-known experiments on the high-temperature dependence of the heat capacity of the titanium carbide TiCx. The proposed formula takes into account the degree of thermal excitation (a quantized number) that increases in steps with increasing temperature.The results allow us to predict the thermodynamic characteristics of titanium carbide in the temperature range of 300–3000 K and can be useful for materials scientists.

scholarly journals Temperature dependence of the rigid amorphous fraction of poly(butylene succinate)

RSC Advances ◽  
2021 ◽  
Vol 11 (41) ◽  
pp. 25731-25737
Author(s):  
Maria Cristina Righetti ◽  
Maria Laura Di Lorenzo ◽  
Patrizia Cinelli ◽  
Massimo Gazzano
Keyword(s):  
Body Temperature ◽  
Temperature Dependence ◽  
Human Body ◽  
Room Temperature ◽  
Rigid Amorphous Fraction ◽  
Butylene Succinate ◽  
Amorphous Fraction ◽  
Human Body Temperature ◽  
Rigid Amorphous

At room temperature and at the human body temperature, all the amorphous fraction is mobile in poly(butylene succinate).

Sign in / Sign up

Export Citation Format

Share Document