scholarly journals Akhiezer mechanism dominates relaxation of propagons in amorphous material at room temperature

2021 ◽  
Vol 130 (3) ◽  
pp. 035101
Author(s):  
Yuxuan Liao ◽  
Junichiro Shiomi
Keyword(s):  
Room Temperature ◽  
Amorphous Material

The Crystallization of a-ZnTe

1975 ◽  
Vol 53 (22) ◽  
pp. 2481-2484 ◽  
Author(s):  
J. B. Webb ◽  
D. E. Brodie
Keyword(s):  
Activation Energy ◽  
Room Temperature ◽  
Crystallization Process ◽  
Amorphous Material ◽  
Amorphous State ◽  
Zinc Telluride ◽  
Thermally Activated ◽  
Maximum Time

The crystallization of amorphous zinc telluride (a-ZnTe) has been studied as a function of temperature in the range 350 K < T < 390 K. The crystallization process is thermally activated with an activation energy of 1.6 eV. The time for the onset of significant crystallization at room temperature for films of air-annealed a-ZnTe is found to be ~100 years. The study of the crystallization process is essential in order to determine the maximum time allowed for a measurement to be performed at a given temperature on a sample of amorphous material without significantly altering its amorphous state.

Fibering of Rubber. Time Lag and Its Relation to Rubber Structure

1934 ◽  
Vol 7 (3) ◽  
pp. 505-515 ◽  
Author(s):  
John D. Long ◽  
William E. Singer ◽  
Wheeler P. Davey
Keyword(s):  
Room Temperature ◽  
Mechanical Energy ◽  
Amorphous Material ◽  
Time Lag ◽  
Temperature History ◽  
Time Interval ◽  
X Rays ◽  
Mechanical Working ◽  
Typical Data ◽  
Lag Effect

Abstract FOR several years it has been known that in the unstretched condition ordinary rubber acts toward x-rays like an amorphous material, but that, when it is sufficiently stretched, it acts toward the rays like a fibrous material. In 1931 Acken, Singer, and Davey (1) reported that at room temperature a time interval was required to build up the fibrous structure in cyclically stretched rubber. Investigation showed that the time-lag effect could not be accounted for in terms of a temperature change during the act of stretching. Even if all the mechanical energy of stretching were instantaneously changed into sensible heat, the temperature of the rubber sample could not have been increased momentarily by more than 5.2° C., whereas the fibering of rubber continuously stretched at 420 per cent elongation could be demonstrated up to a temperature of 47° C. Experimentally no temperature rise greater than 1.0° C. could be found in the samples used. Since the time-lag effect appeared, therefore, to be a real effect, it seemed worth while to study it in detail. It is the purpose of this paper to report: (1) typical data on the effects on the time lag, of temperature, previous temperature history, mechanical working and aging, time of relaxation, time of stretch, and rate of stretch; and (2) the relation of these results to the possible structure of the rubber fiber.

Magnetic and Microstructural Aspects of the Bulk Metallic Glassy Materials Nd60Fe30Al10

2001 ◽  
Vol 674 ◽  
Author(s):  
N. H. Dan ◽  
N. X. Phuc ◽  
V. H. Ky ◽  
N. M. Hong ◽  
N. Chau ◽  
...  
Keyword(s):  
Room Temperature ◽  
Amorphous Material ◽  
Magnetic Hysteresis ◽  
Degree Of Crystallinity ◽  
Nominal Composition ◽  
X Ray Diffraction ◽  
Cast Sample ◽  
X Ray ◽  
Glassy Materials ◽  
Ferromagnetic Bulk

ABSTRACTThe ferromagnetic bulk metallic glass (BMG) Nd60Fe30Al10system exhibits extremely large coercivities at low temperature and moderate coercivities near room temperature. The magnetic hardness, as best evidenced by the onset of magnetic irreversibility, was studied in bulk suction-cast and melt-spun alloys with the nominal composition Nd60Fe30Al10. Systematic x-ray diffraction studies of the degree of crystallinity performed as a function of position within the bulk suction-cast samples is found to correlate with the variation in the room-temperature magnetic hysteresis character. X-ray diffraction data clearly shows the presence of both crystallites and amorphous material on the samples' outmost surfaces; the amorphous phase content increases with distance into the cast sample. These results underscore the importance of solidification conditions and attendant nanophase selection, on the resultant magnetic properties of this class of alloys.

scholarly journals Physical properties of reactive RF sputtered a-IZON thin films.

2019 ◽  
Vol 65 (2) ◽  
pp. 133
Author(s):  
J. J. Ortega ◽  
C. R. Escobedo-Galván ◽  
F. Avelar-Muñoz ◽  
A. A. Ortiz-Hernández ◽  
H. Tototzintle-Huitle ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Physical Properties ◽  
Room Temperature ◽  
Amorphous Material ◽  
Optoelectronic Devices ◽  
Rf Magnetron Sputtering ◽  
High Transparency ◽  
Reactive Rf Magnetron Sputtering ◽  
Incorporated Nitrogen

The physical properties of amorphous indium zinc oxynitride (a-IZON) thin films, which were deposited at room temperature by reactive RF magnetron sputtering, were investigated. The results of the investigations indicated that the a-IZON films possessed excellent qualities: high transparency with a very low resistivity from 10-3 Ω∙cm to 10-4 Ω∙cm, while the carrier concentration showed values over 1020 cm-3 with mobility between 10 and 21 cm2⸱V-1⸱s-1. The incorporated nitrogen reduces the typical crystallization of IZO and favors the deposition of transparent thin films. These results show that the IZON is an ideal amorphous material for applications in transparent and flexible optoelectronic devices.

scholarly journals The elastic properties of steel at moderately high temperatures

1915 ◽  
Vol 91 (628) ◽  
pp. 291-303
Keyword(s):  
Viscous Fluid ◽  
Elastic Properties ◽  
Room Temperature ◽  
Amorphous Material ◽  
Good Deal ◽  
Torsional Stress ◽  
Steel Tubes ◽  
Permanent Set ◽  
Stress Strain Relation ◽  
Suitable Temperature

In a recent paper the author give the results of measurements of the elastic hysteresis of steel tubes, when subjected to torsional stress, within what is ordinary room temperature, and the chief points established by them were, that the hysteresis of the hard-drawn tubes is much less than that for the same tubes after annealing, and that in the latter case, the loss of energy in the cycle of stress is independent of the speed of performance of the cycle, or, in other words, time is not a factor in the stress-strain relation.. The present research is the outcome of a suggestion by Prof. B. Hopkinson, that at a suitable temperature the hard-drawn tube, which contains a good deal of amorphous material, would begin to behave like a viscous fluid, that is, it would flow more or less freely when under stress, whereas at the same temperature, the annealed tube, being crystalline, though it might take a permanent set, could not flow, or would flow in a much less degree corresponding to the small amount of amorphous material in it.

Microstructure of radiation-damaged zircon under pressure

2003 ◽  
Vol 36 (4) ◽  
pp. 1006-1012 ◽  
Author(s):  
Susana Ríos ◽  
Tiziana Boffa-Ballaran
Keyword(s):  
Room Temperature ◽  
High Pressures ◽  
Amorphous Matrix ◽  
Amorphous Material ◽  
Uniform Structure ◽  
Simultaneous Increase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Peak Intensity ◽  
Crystalline Domains

Radiation-damaged zircons have been studied at high pressures, up to 7 GPa, by means of single-crystal X-ray diffraction at room temperature. The zircons studied contained high fractions of amorphous material (65 and 85%, respectively). Peak profiles of selected Bragg reflections at room pressure give evidence of the complex microstructure of defective crystalline regions. A differential stress of ∼20 GPa is found between expanded and compressed regions. Two clear stages are observed as a function of pressure: (i) below 3 GPa, diffraction maxima do not show significant changes; (ii) above 3 GPa, a simultaneous increase in peak intensity and decrease in mosaic spread is observed. The effects are attributed to reorientation of crystalline domains within the amorphous matrix. The starting peak profile is recovered after releasing pressure, implying that no significant defect healing is induced in this pressure range, and that all observed effects are reversible. Results are interpreted in terms of the non-uniform structure of amorphous cascades.

Neutron Diffraction Study of Highly Radioactive U3Si2 Reactor Fuel

1994 ◽  
Vol 373 ◽  
Author(s):  
J. W. Richardson ◽  
R. C. Birtcher ◽  
M. H. Mueller
Keyword(s):  
Neutron Diffraction ◽  
Room Temperature ◽  
Amorphous Material ◽  
Neutron Diffraction Study ◽  
General Purpose ◽  
Crystalline Lattice ◽  
Sample Container ◽  
Scattering Pattern ◽  
Nanocrystalline Particles ◽  
Mini Plate

AbstractNeutron diffraction data were collected from a highly radioactive, low-enrichment uraniumU3Si2/A1 fuel mini-plate that had been irradiated to 42% uranium burnup. The experiment was performed using the General Purpose Powder Diffractometer at IPNS. Most prominent in the diffraction pattern were the Bragg reflections from crystalline Al (fuel plate) and V (sample container). Rietveld refinement revealed a broad oscillatory signal from the U3Si2 typical of amorphous material. This “amorphous” scattering pattern has peaks at the same positions as the amorphous scattering components observed following room temperature neutron irradiation of U3Si2 powder. The irradiated U3Si2 is amorphous with a remote possibility that it consists of recrystallized nanocrystalline particles subject to the requirements that the crystallites: (i) are no larger than 100-200 Å in size, and (ii) possess a crystalline lattice which is distorted relative to the unirradiated material.

An electronic structure for a-ZnSe

1977 ◽  
Vol 55 (19) ◽  
pp. 1641-1647 ◽  
Author(s):  
P. K. Lim ◽  
D. E. Brodie
Keyword(s):  
Optical Properties ◽  
Electronic Structure ◽  
Room Temperature ◽  
Amorphous Material ◽  
Amorphous Semiconductor ◽  
Drift Mobility ◽  
Type Model ◽  
Electrical And Optical Properties ◽  
Energy Level Scheme ◽  
Consistent Manner

Some electrical and optical properties for a-ZnSe have been studied and the results have been analysed in a consistent manner with the help of a Mott-type model for an amorphous semiconductor. Mature samples are reproducible and for these an energy level scheme is obtained. Many experiments are required to characterize an amorphous material and hence we have presented the results for dc conductivity, photoconductivity, optical absorption, thermoelectric power, ac conductivity, and drift mobility experiments for this material. a-ZnSe is n-type, with the Fermi level near the middle of the mobility gap. Drift mobilities are dispersive and have values of the order of 10−6 cm2 V−1 s−1 at room temperature.

Dependence of Intergranular Fracture on Boundary Topography and Cohesion

1973 ◽  
Vol 31 ◽  
pp. 150-151
Author(s):  
J. E. Doherty ◽  
A. F. Giamei ◽  
B. H. Kear ◽  
C. W. Steinke
Keyword(s):  
Grain Boundary ◽  
Room Temperature ◽  
Nickel Base Superalloy ◽  
Boundary Shear ◽  
Room Temperature Ductility ◽  
Solid Solution Matrix ◽  
Nickel Base ◽  
Solution Matrix ◽  
Different Levels ◽  
Base Superalloy

Recently we have been investigating a class of nickel-base superalloys which possess substantial room temperature ductility. This improvement in ductility is directly related to improvements in grain boundary strength due to increased boundary cohesion through control of detrimental impurities and improved boundary shear strength by controlled grain boundary micros true tures.For these investigations an experimental nickel-base superalloy was doped with different levels of sulphur impurity. The micros tructure after a heat treatment of 1360°C for 2 hr, 1200°C for 16 hr consists of coherent precipitates of γ’ Ni3(Al,X) in a nickel solid solution matrix.

Hepatocyte Alterations in Guinea Pigs FED Polychlorinated Biphenyls (PCBs), Dibenzodioxins (PCDD), AND DIBENZOFURANS (PCDF)

1982 ◽  
Vol 40 ◽  
pp. 56-57
Author(s):  
J. N. Turner ◽  
D. N. Collins
Keyword(s):  
Guinea Pigs ◽  
Room Temperature ◽  
Dose Group ◽  
Methyl Cellulose ◽  
Uranyl Acetate ◽  
Target Organ ◽  
Office Building ◽  
Lead Citrate ◽  
Control Groups ◽  
Cooling Fluid

A fire involving an electric service transformer and its cooling fluid, a mixture of PCBs and chlorinated benzenes, contaminated an office building with a fine soot. Chemical analysis showed PCDDs and PCDFs including the highly toxic tetra isomers. Guinea pigs were chosen as an experimental animal to test the soot's toxicity because of their sensitivity to these compounds, and the liver was examined because it is a target organ. The soot was suspended in 0.75% methyl cellulose and administered in a single dose by gavage at levels of 1,10,100, and 500mgm soot/kgm body weight. Each dose group was composed of 6 males and 6 females. Control groups included 12 (6 male, 6 female) animals fed activated carbon in methyl cellulose, 6 males fed methyl cellulose, and 16 males and 10 females untreated. The guinea pigs were sacrificed at 42 days by suffocation in CO2. Liver samples were immediately immersed and minced in 2% gluteraldehyde in cacadylate buffer at pH 7.4 and 4°C. After overnight fixation, samples were postfixed in 1% OsO4 in cacodylate for 1 hr at room temperature, embedded in epon, sectioned and stained with uranyl acetate and lead citrate.

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