scholarly journals The Electrical and Thermal Conductivities of Monovalent Metals

1954 ◽  
Vol 7 (1) ◽  
pp. 70 ◽  
Author(s):  
PG Klemens
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Fermi Surface ◽  
Reasonable Agreement ◽  
Spherical Shape ◽  
Lattice Vibrations ◽  
Electron Theory ◽  
Transverse Lattice ◽  
Conduction Electrons ◽  
Thermal Conductivities

The experimentally determined values of the high and low temperature electrical and thermal conductivities of pure sodium, copper, silver, and gold are such that the ratios of these quantities for each of these metals do not agree with the values expected from the Bloch free electron theory, except for the high temperature Wiedemann-Franz ratio. Reasonable agreement can be achieved by assuming (i) that the conduction electrons can interact directly with transverse lattice vibrations, and (ii) that the Fermi surface departs significantly from spherical shape in all these metals, and touches the boundary of the Brillouin zone in the case of copper, silver, and gold.

The relaxation time of conduction electrons in the noble met

1963 ◽  
Vol 275 (1361) ◽  
pp. 209-217 ◽  
Keyword(s):  
Electrical Conductivity ◽  
Relaxation Time ◽  
Boltzmann Equation ◽  
Fermi Surface ◽  
Low Temperatures ◽  
Lattice Vibrations ◽  
Thermo Electric ◽  
Multiply Connected ◽  
Conduction Electrons ◽  
Experimental Values

The Boltzmann equation for scattering by impurities and lattice vibrations is solved numerically for a metal having a multiply-connected Fermi surface. It is found that the relaxation time for scattering by lattice vibrations at high temperatures or by impurities is approximately constant over the Fermi surface. For scattering by lattice vibrations at low temperatures the relaxation time is highly anisotropic. These results are consistent with the experimental values of the electrical conductivity but cannot predict a positive thermo ­ electric power.

Infrared and Raman Spectra of Potassium and Sodium Borohydride

1971 ◽  
Vol 49 (20) ◽  
pp. 3272-3281 ◽  
Author(s):  
K. B. Harvey ◽  
N. R. McQuaker
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Raman Spectra ◽  
Sodium Borohydride ◽  
Vibrational Spectra ◽  
Phase Changes ◽  
Lattice Vibrations ◽  
Infrared And Raman Spectra ◽  
Laser Raman ◽  
Potassium Borohydride

Using both infrared and laser Raman techniques the low temperature vibrational spectra of KBH4, KBD4, NaBH4, and NaBD4 have been recorded. The spectra of the external lattice vibrations are consistent with the following borohydride ion site symmetries: Td for potassium borohydride and D2d for sodium borohydride. Translational frequencies are assigned and librational frequencies are inferred from absorptions tentatively assigned as second overtones. Comparison of the low and high temperature vibrational spectra suggests the following disorder–order phase changes: Oh5 → Td2 for potassium borohydride and Oh5 → D2d9 for sodium borohydride.

THERMOPOWER OF THE LAYERED MULTI-BAND SUPERCONDUCTOR Sr2RuO4

2003 ◽  
Vol 17 (04n06) ◽  
pp. 668-673
Author(s):  
MARIO CUOCO ◽  
CANIO NOCE
Keyword(s):  
Experimental Data ◽  
High Temperature ◽  
Boltzmann Equation ◽  
Low Temperature ◽  
Fermi Surface ◽  
Hall Coefficient ◽  
Surface Curvature ◽  
Band Calculation ◽  
The Boltzmann Equation ◽  
Multi Band

The dependence of in-plane thermopower and Hall coefficient of Sr 2 RuO 4 on temperature are discussed. The apparently contradiction found in experimental data in the sign of these quantities at low temperature is clarified within a simple multi-band calculation. Then, by means of the Boltzmann equation and taking into account the Fermi surface curvature and different time collisions for the electrons in the t2g bands, the calculation is extended at high temperature.

Exsolution and inversion in pigeonite from the Whin Sill, Northern England

1978 ◽  
Vol 36 (1) ◽  
pp. 474-475
Author(s):  
P.P.K. Smith
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Homogeneous Nucleation ◽  
Silicate Mineral ◽  
Antiphase Boundaries ◽  
Two Phase ◽  
Primitive Form ◽  
The Core ◽  
Nucleation Mechanisms ◽  
And Inversion

Grains of pigeonite, a calcium-poor silicate mineral of the pyroxene group, from the Whin Sill dolerite have been ion-thinned and examined by TEM. The pigeonite is strongly zoned chemically from the composition Wo8En64FS28 in the core to Wo13En34FS53 at the rim. Two phase transformations have occurred during the cooling of this pigeonite:- exsolution of augite, a more calcic pyroxene, and inversion of the pigeonite from the high- temperature C face-centred form to the low-temperature primitive form, with the formation of antiphase boundaries (APB's). Different sequences of these exsolution and inversion reactions, together with different nucleation mechanisms of the augite, have created three distinct microstructures depending on the position in the grain.In the core of the grains small platelets of augite about 0.02μm thick have farmed parallel to the (001) plane (Fig. 1). These are thought to have exsolved by homogeneous nucleation. Subsequently the inversion of the pigeonite has led to the creation of APB's.

Superconducting Wind Generators with Capacities of 10 MW and Larger

2020 ◽  
Vol 10 (10) ◽  
pp. 59-67
Author(s):  
Victor N. ANTIPOV ◽  
◽  
Andrey D. GROZOV ◽  
Anna V. IVANOVA ◽  
◽  
...  
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Wind Power ◽  
State Of The Art ◽  
Superconducting Materials ◽  
Commercial Application ◽  
Synchronous Generators ◽  
High Temperature Superconducting ◽  
Wind Generators ◽  
Main Factor

The overall dimensions and mass of wind power units with capacities larger than 10 MW can be improved and their cost can be decreased by developing and constructing superconducting synchronous generators. The article analyzes foreign conceptual designs of superconducting synchronous generators based on different principles: with the use of high- and low-temperature superconductivity, fully superconducting or only with a superconducting excitation system, and with the use of different materials (MgB2, Bi2223, YBCO). A high cost of superconducting materials is the main factor impeding commercial application of superconducting generators. In view of the state of the art in the technology for manufacturing superconductors and their cost, a conclusion is drawn, according to which a synchronous gearless superconducting wind generator with a capacity of 10 MW with the field winding made of a high-temperature superconducting material (MgB2, Bi-2223 or YBCO) with the «ferromagnetic stator — ferromagnetic rotor» topology, with the stator diameter equal to 7—9 m, and with the number of poles equal to 32—40 has prospects for its practical use in the nearest future.

SOMERS LTA COPPER

Alloy Digest ◽  
1980 ◽  
Vol 29 (12) ◽  
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Physical Properties ◽  
Copper Foil ◽  
Heat Treating ◽  
Dielectric Substrates ◽  
Printed Circuits

Abstract SOMERS LTA Copper is a wrought copper foil that can be annealed at 350 F in 15 minutes to the full-soft condition; its use simplifies the manufacture of printed circuits (LTA = Low-Temperature Annealable). LTA Copper is especially useful for foil weights up to and including one ounce per square foot (0.0014-inch thick) for laminating to high-temperature dielectric substrates. This datasheet provides information on composition, physical properties, and elasticity as well as fatigue. It also includes information on forming, heat treating, and machining. Filing Code: Cu-407. Producer or source: Olin Corporation.

CHRO-MOW

Alloy Digest ◽  
1958 ◽  
Vol 7 (2) ◽  
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Heat Treating ◽  
Steel Company ◽  
Temperature Performance ◽  
Hot Work Steel ◽  
Crucible Steel ◽  
Red Hardness

Abstract CHRO-MOW is a tough hot work steel which will harden from a relatively low temperature in air. It possesses a desirable combination of toughness and red-hardness. This datasheet provides information on composition, physical properties, hardness, and tensile properties. It also includes information on high temperature performance as well as forming, heat treating, and machining. Filing Code: TS-67. Producer or source: Crucible Steel Company of America.

NICLOY 5

Alloy Digest ◽  
1960 ◽  
Vol 9 (3) ◽  
Keyword(s):  
Fracture Toughness ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Low Temperature ◽  
Physical Properties ◽  
Tensile Properties ◽  
Ferritic Steel ◽  
Heat Treating ◽  
Low Carbon ◽  
Temperature Performance

Abstract NICLOY 5 is a low carbon, nickel ferritic steel reecommended for low temperature service. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SA-96. Producer or source: Babcock & Wilcox Company.

The Application of X-Ray Diffraction at Elevated Temperatures to Study the Mechanism of Formation of Sodium Tripolyphosphate

1961 ◽  
Vol 5 ◽  
pp. 276-284
Author(s):  
E. L. Moore ◽  
J. S. Metcalf
Keyword(s):  
High Temperature ◽  
Low Temperature ◽  
Amorphous Phase ◽  
Elevated Temperatures ◽  
Sodium Tripolyphosphate ◽  
X Ray Diffraction ◽  
Mechanism Of Formation ◽  
X Ray ◽  
Temperature Form ◽  
High Temperature Form

AbstractHigh-temperature X-ray diffraction techniques were employed to study the condensation reactions which occur when sodium orthophosphates are heated to 380°C. Crystalline Na4P2O7 and an amorphous phase were formed first from an equimolar mixture of Na2HPO4·NaH2PO4 and Na2HPO4 at temperatures above 150°C. Further heating resulted in the formation of Na5P3O10-I (high-temperature form) at the expense of the crystalline Na4P4O7 and amorphous phase. Crystalline Na5P3O10-II (low-temperature form) appears after Na5P3O10-I.Conditions which affect the yield of crystalline Na4P2O7 and amorphous phase as intermediates and their effect on the yield of Na5P3O10 are also presented.

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