scholarly journals Sintering process and temperature dependence of the dielectric behavior of snow samples

2003 ◽  
Vol 65 (6) ◽  
pp. 511-522
Author(s):  
Iwao TAKEI
Keyword(s):  
Temperature Dependence ◽  
Dielectric Behavior ◽  
Sintering Process ◽  
Snow Samples

Investigation of Polarization Mechanism of Relaxor Ferroelectrics

1996 ◽  
Vol 453 ◽  
Author(s):  
Z. -Y. Cheng ◽  
R. S. Katiyar ◽  
Yao Xi
Keyword(s):  
Dielectric Constant ◽  
Low Temperature ◽  
Temperature Dependence ◽  
High Precision ◽  
Relaxor Ferroelectrics ◽  
Dielectric Behavior ◽  
Polar Regions ◽  
Thermally Activated ◽  
Polarization Mechanism ◽  
Constant Maximum

AbstractAddition to thermally activated flips of polar regions in relaxor ferroelectrics, a new polarization mechanism, which originates from the vibrations (breathing) of surface of polar regions, is introduced to explain the dielectric behavior of relaxor ferroelectrics. This new mechanism plays an important role in the dielectric behavior of such materials at low temperature. Based on the above assumption and general dielectric theory, a formula is given to characterize the temperature dependence of the dielectric constant. The correctness of the formula is verified by using it to fit the experimental results of the two typical relaxors. The fitted results show that the method is of high precision and that the temperature of the dielectric constant maximum is decided by the two polarization behavior. It also indicates that the new polarization is a resonance polarization.

Rescaled temperature dependence of dielectric behavior of ferroelectric polymer composites

2005 ◽  
Vol 86 (17) ◽  
pp. 172905 ◽  
Author(s):  
Zhi-Min Dang ◽  
Lan Wang ◽  
Hai-Yan Wang ◽  
Ce-Wen Nan ◽  
Dan Xie ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Polymer Composites ◽  
Dielectric Behavior ◽  
Ferroelectric Polymer

scholarly journals The Sintering Process in Snow

1966 ◽  
Vol 6 (45) ◽  
pp. 421-424 ◽  
Author(s):  
René O. Ramseier ◽  
Charles M. Keeler
Keyword(s):  
Mass Transfer ◽  
Unconfined Compressive Strength ◽  
Volume Diffusion ◽  
Silicone Oil ◽  
The Other ◽  
Atmospheric Conditions ◽  
Sintering Process ◽  
Transfer Coefficients ◽  
Major Mechanism ◽  
Snow Samples

The growth of bonds between snow grains or ice spheres has been variously attributed to surface diffusion, volume diffusion, and evaporation–condensation. To distinguish among these possible mechanisms the unconfined compressive strength of two groups of snow samples was determined as a function of time. One group was allowed to sinter under atmospheric conditions while the other group was kept immersed in silicone oil. The much lower rate of strengthening of the latter group suggests that evaporation–condensation must be the major mechanism of mass transport in snow under atmospheric conditions. The possible magnitudes of the various mass transfer coefficients are discussed.

scholarly journals The Sintering Process in Snow

1966 ◽  
Vol 6 (45) ◽  
pp. 421-424 ◽  
Author(s):  
René O. Ramseier ◽  
Charles M. Keeler
Keyword(s):  
Mass Transfer ◽  
Unconfined Compressive Strength ◽  
Volume Diffusion ◽  
Silicone Oil ◽  
The Other ◽  
Atmospheric Conditions ◽  
Sintering Process ◽  
Transfer Coefficients ◽  
Major Mechanism ◽  
Snow Samples

The growth of bonds between snow grains or ice spheres has been variously attributed to surface diffusion, volume diffusion, and evaporation–condensation. To distinguish among these possible mechanisms the unconfined compressive strength of two groups of snow samples was determined as a function of time. One group was allowed to sinter under atmospheric conditions while the other group was kept immersed in silicone oil. The much lower rate of strengthening of the latter group suggests that evaporation–condensation must be the major mechanism of mass transport in snow under atmospheric conditions. The possible magnitudes of the various mass transfer coefficients are discussed.

scholarly journals Studies of electrical conductivity and magnetic properties of Bi1-xGdxFeO3 multiferroics

2014 ◽  
Vol 04 (02) ◽  
pp. 1450011 ◽  
Author(s):  
Samita Pattanayak ◽  
R. N. P. Choudhary ◽  
Piyush R. Das
Keyword(s):  
Temperature Dependence ◽  
Room Temperature ◽  
Spontaneous Magnetization ◽  
Sample Surface ◽  
Dielectric Behavior ◽  
Arrhenius Behavior ◽  
Universal Power Law ◽  
Wide Range ◽  
Temperature Scanning ◽  
Frequency Temperature

The polycrystalline samples of Bi 1-x Gd x FeO 3 (x = 0, 0.1, and 0.2) multiferroic oxides have been synthesized by a solid-state reaction/mixed oxide technique. The preliminary X-ray structural analysis with room temperature diffraction data confirmed the formation of single-phase systems. Study of room temperature scanning electron micrograph (SEM) of the surface of the above samples exhibits a uniform distribution of plate- and rod-shaped grains throughout the sample surface with less porosity. The dielectric behavior of the materials was studied in a wide range of frequency (1 kHz–1 MHz) and temperature (30–400°C). The nature of temperature dependence of dc conductivity confirms the Arrhenius behavior of the materials. The frequency–temperature dependence of ac conductivity suggests that the material obeys Jonscher's universal power law. An increase in Gd -content results in the enhancement of spontaneous magnetization BiFeO 3 (BFO) due to the collapse of spin cycloid structure. The magnetoelectric coupling coefficient of BFO has been enhanced on Gd -substitution.

Temperature Dependence of the Critical Electron Dose for Fatty Acid Monolayers

1982 ◽  
Vol 40 ◽  
pp. 78-79
Author(s):  
Kenneth H. Downing ◽  
Robert M. Glaeser
Keyword(s):  
Electron Beam ◽  
Fatty Acid ◽  
Inelastic Scattering ◽  
Temperature Dependence ◽  
Structural Damage ◽  
Direct Result ◽  
Second Step ◽  
Strong Temperature Dependence ◽  
Electron Dose ◽  
Covalent Bonds

The structural damage of molecules irradiated by electrons is generally considered to occur in two steps. The direct result of inelastic scattering events is the disruption of covalent bonds. Following changes in bond structure, movement of the constituent atoms produces permanent distortions of the molecules. Since at least the second step should show a strong temperature dependence, it was to be expected that cooling a specimen should extend its lifetime in the electron beam. This result has been found in a large number of experiments, but the degree to which cooling the specimen enhances its resistance to radiation damage has been found to vary widely with specimen types.

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