Uniaxial stress and strain derivatives of the Fermi-surface necks in gold

1987 ◽  
Vol 65 (1) ◽  
pp. 13-15 ◽  
Author(s):  
H. Klimker ◽  
J. M. Perz ◽  
M. J. G. Lee
Keyword(s):  
Tensile Stress ◽  
Fermi Surface ◽  
Uniaxial Stress ◽  
Uniaxial Tensile ◽  
Direct Tension ◽  
Pressure Derivative ◽  
Cross Sectional ◽  
Uniaxial Tensile Stress ◽  
Compression Data ◽  
Derivatives Of

Simultaneous measurements of quantum oscillations in magnetostriction and torque in a single crystal of gold have been used to determine precise values for the derivatives of the cross-sectional area of the [111] neck of the Fermi surface with respect to uniaxial tensile stress along the [110] and [Formula: see text] directions. Independent estimates of the derivative with respect to uniaxial tensile stress along [111] of the neck area have been deduced from appropriate combinations of the [110] and [Formula: see text] stress derivatives with the established hydrostatic-pressure derivative. These estimates are in excellent agreement, giving ∂ lnA111/∂σ111 = (11.5 ± 0.3) × 10−12cm2∙dyn−1 (1 dyn = 10 μN). This result is significantly larger than the result of early direct-tension measurements in gold, suggesting that the latter suffered from systematic error. The present result is consistent with, and more precise than, earlier magnetostriction and direct uniaxial compression data. The angular shear derivative ∂ ln A/∂γ = 5.56 ± 0.17, deduced from the present data, is slightly larger than the theoretical value of 4.80 ± 0.20 obtained from a relativistic Korringa–Kohn–Rostoker phase-shift calculation based a rigid spherical muffin-tin pseudopotential.

Hydrostatic pressure and uniaxial stress derivatives of the Fermi surface of rhenium

1983 ◽  
Vol 61 (10) ◽  
pp. 1428-1433 ◽  
Author(s):  
J. R. Anderson ◽  
F. W. Holroyd ◽  
J. M. Perz ◽  
J. E. Schirber ◽  
I. M. Templeton
Keyword(s):  
Transition Temperature ◽  
Hydrostatic Pressure ◽  
Fermi Surface ◽  
Cross Sections ◽  
Solid Helium ◽  
Uniaxial Stress ◽  
Superconducting Transition ◽  
Cross Sectional ◽  
Effective Masses ◽  
Derivatives Of

Derivatives with respect to hydrostatic pressure of extremal cross-sectional areas normal to [Formula: see text] of all closed sheets of the Fermi surface of rhenium have been determined by both fluid–helium and solid–helium phase shift techniques. Precise values of de Haas–van Alphen frequencies and effective masses have also been measured for these cross sections. In addition, uniaxial stress derivatives of the zone seven cross sections have been deduced from quantum oseillations in magnetostriction and torque. Previously observed anomalies in the pressure dependence of the superconducting transition temperature are interpreted in terms of the present results.

Uniaxial strain dependence of the Fermi surface of tungsten

1977 ◽  
Vol 55 (4) ◽  
pp. 344-355 ◽  
Author(s):  
D. J. Stanley ◽  
J. M. Perz ◽  
M. J. G. Lee ◽  
R. Griessen
Keyword(s):  
Fermi Surface ◽  
Uniaxial Stress ◽  
Cross Sectional ◽  
Quantum Oscillations ◽  
Scattering Phase ◽  
Point Determination ◽  
Derivatives Of ◽  
Homogeneous Strain ◽  
Good Agreement

The derivatives of five representative cross sectional areas of the Fermi surface of tungsten with respect to uniaxial stress and strain along the cube axes, are determined experimentally from simultaneous measurements of quantum oscillations in magnetostriction and torque, and also in sound velocity and torque. The results are resolved into two components, the dependence on volume-conserving tetragonal shear, and the dependence on isotropic dilation. The tetragonal shear dependence is found to be in generally good agreement with the results of KKR calculations based on a fit to the unstrained Fermi surface. The isotropic dilation dependence agrees well with hydrostatic pressure measurements; from these results, the volume derivatives of the scattering phase shifts are deduced. This work is the first step towards a point-by-point determination of the distortion of the Fermi surface of tungsten in a lattice subjected to an arbitrary homogeneous strain.

Fracture Behaviors of Dam and Wet-Sreening Concrete by Direct Tensile Test

2008 ◽  
Vol 400-402 ◽  
pp. 233-238 ◽  
Author(s):  
Zhi Fang Zhao ◽  
Bo Pang ◽  
Zhi Gang Zhao
Keyword(s):  
Tensile Stress ◽  
Crack Width ◽  
Testing Machine ◽  
Tensile Load ◽  
Uniaxial Tensile ◽  
Direct Tension ◽  
Fracture Parameters ◽  
Fracture Behaviors ◽  
Uniaxial Tensile Stress ◽  
Dam Concrete

The emphasis of this paper is to experimentally study the fracture behaviors of dam and wet-screening concrete such as softening curve, uniaxial tensile strength , maximum crack width and fracture energy . The direct tension tests were performed on prismatic specimens with no initial notch include dam concrete specimens which size is 250mm×250mm×500mm and wet-screening concrete specimens which size is 150mm×150mm×300mm by employing a servo-hydraulic closed-loop testing machine with large stiffness. The uniaxial tensile load-strain curves, uniaxial tensile stress-strain curves, uniaxial tensile stress-deformation curves were acquired. On the basis of principle of fracture mechanics of concrete, the stress-crack width curves and the relative stress-relative crack width curves were obtained. Finally, the expressions of softening curves and fracture parameters such as , and of dam and wet-screening concrete were achieved. The relationships of the foregoing fracture parameters between dam concrete and wet-screening concrete were discussed in this paper. The achieved softening curves and fracture parameters can provide input data for the fracture simulating analysis of dam and wet-screening concrete.

Experimental uniaxial stress and strain derivatives of the Fermi surface of rhenium

1980 ◽  
Vol 58 (8) ◽  
pp. 1191-1199 ◽  
Author(s):  
E. Fawcett ◽  
F. W. Holroyd ◽  
J. M. Perz
Keyword(s):  
Fermi Surface ◽  
Uniaxial Stress ◽  
Stress And Strain ◽  
Strong Anisotropy ◽  
Quantum Oscillations ◽  
Band Structure Calculations ◽  
Landau Quantum ◽  
Derivatives Of ◽  
Structure Calculations ◽  
The Magnetic Field

The derivatives of the areas of extremal orbits on all the small sheets of the Fermi surface of rhenium, with respect to stress and strain along the hexad axis, have been determined from simultaneous measurements of Landau quantum oscillations in magnetostriction and torque, and also in sound velocity and torque. Strong anisotropy is observed in the stress derivatives of orbits in zones five and six as the direction of the magnetic field defining the normal to the orbit is varied; the anisotropy is most pronounced for orbits which come close to the line of degeneracy AL on the hexagonal Brillouin zone face. The derivatives of the small void in zone eight are found to be very large; this is consistent with the results of band structure calculations which show that this feature of the Fermi surface is very sensitive to small changes in the Fermi energy. Cyclotron effective masses for a number of orbits on the void have also been measured.

scholarly journals Determination of Direct Tensile Strength Values of Rock Materials by a New Test Method of Drilled Disc Tension

2019 ◽  
Author(s):  
Eren Komurlu ◽  
Serhat Demir
Keyword(s):  
Tensile Strength ◽  
Experimental Studies ◽  
Test Method ◽  
Uniaxial Tensile ◽  
Direct Tension ◽  
Rock Materials ◽  
Uniaxial Tensile Stress ◽  
Direct Tensile ◽  
Drill Holes ◽  
Direct Tensile Strength

Use of drilled disc specimens was investigated with both numerical and experimental studies to determine direct tensile strengths of rock materials. A new loading apparatus with rods to insert into the drill holes of discs has been designed and manufactured to supply tension by using the compression test presses. In addition to the use of popular compressive presses for direct tension, elimination of the gluing in the standard direct tensile strength test method is a significant advantage to make possible both hard and soft rocks to be tested. The Brazilian test discs with the diameter of NX size and length to diameter ratio of 0.5 were used in tests. Different loading apparatus designs were analyzed and ideal angle of contact between rock and the loading rods was assessed to be 50° within various choices investigated in this study. The drilled discs were determined to fail due to the crack initiation under the condition of uniaxial tensile stress distribution at sidewalls of the hole. In addition to the drilled disc tension test, standard direct tensile strength tests were also carried out to take as reference and compare the results obtained from different methods. According to the results of both numerical and experimental studies, an equation was suggested to determine uniaxial tensile strengths of drilled disc specimens with 20 mm hole diameter and the contact angle of 50°.

scholarly journals Mechanical behaviour and structure of snow under uniaxial tensile stress

1980 ◽  
Vol 26 (94) ◽  
pp. 275-282 ◽  
Author(s):  
Hidek Narita
Keyword(s):  
Tensile Stress ◽  
Strain Rate ◽  
Mechanical Behaviour ◽  
Maximum Strength ◽  
Ductile Deformation ◽  
Uniaxial Tensile ◽  
Strain Rates ◽  
Thin Sections ◽  
Uniaxial Tensile Stress ◽  
Small Cracks

AbstractThe mechanical behaviour of snow was studied at — 10°C under uniaxial tensile stress in a range of cross-head speed 6.8 × 10–8to 3.1 × 10–4ms–1and snow density 240-470 kg m–3.It was found from the resisting force-deformation curves that the snow was deformed in two different ways: namely, brittle and ductile deformation at high and low strain-rates, respectively. The critical strain-rate dividing the two deformation modes was found to depend on the density of snow. In ductile deformation, many small cracks appeared throughout the entire specimen. Their features were observed by making thin sections and they were compared with small cracks formed in natural snow on a mountain slope.The maximum strength of snow was found to depend on strain-rate: at strain-rates above about 10–5s–1, the maximum strength increased with decreasing strain-rate but below 10–5s–1it decreased with decreasing strain-rate.

scholarly journals Mechanical behaviour and structure of snow under uniaxial tensile stress

1980 ◽  
Vol 26 (94) ◽  
pp. 275-282 ◽  
Author(s):  
Hidek Narita
Keyword(s):  
Tensile Stress ◽  
Strain Rate ◽  
Mechanical Behaviour ◽  
Maximum Strength ◽  
Ductile Deformation ◽  
Uniaxial Tensile ◽  
Strain Rates ◽  
Thin Sections ◽  
Uniaxial Tensile Stress ◽  
Small Cracks

AbstractThe mechanical behaviour of snow was studied at — 10°C under uniaxial tensile stress in a range of cross-head speed 6.8 × 10–8 to 3.1 × 10–4 ms–1 and snow density 240-470 kg m–3.It was found from the resisting force-deformation curves that the snow was deformed in two different ways: namely, brittle and ductile deformation at high and low strain-rates, respectively. The critical strain-rate dividing the two deformation modes was found to depend on the density of snow. In ductile deformation, many small cracks appeared throughout the entire specimen. Their features were observed by making thin sections and they were compared with small cracks formed in natural snow on a mountain slope.The maximum strength of snow was found to depend on strain-rate: at strain-rates above about 10–5 s –1, the maximum strength increased with decreasing strain-rate but below 10–5 s–1 it decreased with decreasing strain-rate.

The damage mechanism of 17vol.%SiCp/Al composite under uniaxial tensile stress

2020 ◽  
Vol 782 ◽  
pp. 139274 ◽  
Author(s):  
Qiuyan Shen ◽  
Zhanwei Yuan ◽  
Huan Liu ◽  
Xuemin Zhang ◽  
Qinqin Fu ◽  
...  
Keyword(s):  
Tensile Stress ◽  
Damage Mechanism ◽  
Uniaxial Tensile ◽  
Al Composite ◽  
Uniaxial Tensile Stress
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