Transport properties of tungsten-doped VO2

1976 ◽  
Vol 54 (4) ◽  
pp. 408-412 ◽  
Author(s):  
J. M. Reyes ◽  
M. Sayer ◽  
R. Chen
Keyword(s):  
Transport Properties ◽  
Effective Mass ◽  
Conduction Band ◽  
Ac Conductivity ◽  
Impurity Content ◽  
Donor Level ◽  
Mass Ratio ◽  
Compensation Ratio ◽  
Dc And Ac Conductivity ◽  
Effective Mass Ratio

Measurements of DC and AC conductivity and thermopower show that VO2: W can be treated as a conventional n-type extrinsic semiconductor with a donor level 0.06–0.08 eV below the conduction band. For samples with an impurity content from 0.67 → 1.70 at.% W, an effective mass ratio m*/m of 65 ± 10 and a compensation ratio of 0.7 ± 0.1 are deduced from conventional semiconductor theory assuming donor exhaustion just below the metal semiconductor transition.

de Haas–van Alphen Effect and Localized Spin Fluctuations in Dilute Al–Mn Alloys

1971 ◽  
Vol 49 (13) ◽  
pp. 1813-1822 ◽  
Author(s):  
B. E. Paton
Keyword(s):  
Effective Mass ◽  
Localized States ◽  
Spin Fluctuations ◽  
Mass Ratio ◽  
Electron Phonon Interaction ◽  
Impurity Atoms ◽  
Localized State ◽  
Effective Mass Ratio ◽  
Field Modulation ◽  
Impurity Sites

The de Haas–van Alphen effect in dilute alloys of aluminum-manganese has been measured using the field modulation technique at magnetic fields up to 60 kG and temperatures between 1.1 and 4.2 °K. The period, effective mass ratio, and collision parameter of the third zone y orbits were found to increase linearly on alloying. The increase in the collision parameter attributed to the resonant d scattering by the localized states on the impurity atoms was found to be approximately 10 times larger than the increase observed in aluminum alloys with nontransition element impurities. The effective mass ratio was shown to be enhanced by the electron–phonon interaction and by the localized spin fluctuations on the impurity sites. The parameters which describe the localized state were calculated from the experimental results in the framework of a renormalized theory of localized spin fluctuations and were found to be in agreement with similar parameters calculated from other physical properties. The de Haas–van Alphen results are consistent with the conclusion that the localized state of manganese impurities in aluminum are nonmagnetic but strongly enhanced by localized spin fluctuations.

Transport properties of CVD diamond elucidated by DC and AC conductivity measurements

2004 ◽  
Vol 13 (2) ◽  
pp. 277-281 ◽  
Author(s):  
G Conte ◽  
M.C Rossi ◽  
S Salvatori ◽  
F Spaziani ◽  
G Vitale ◽  
...  
Keyword(s):  
Transport Properties ◽  
Ac Conductivity ◽  
Cvd Diamond ◽  
Conductivity Measurements ◽  
Dc And Ac Conductivity ◽  
Ac Conductivity Measurements

Measurement of the Modeling Parameters for a Maxiflex “B” Springboard

1990 ◽  
Vol 6 (3) ◽  
pp. 325-335 ◽  
Author(s):  
Eric J. Sprigings ◽  
Denise S. Stilling ◽  
L. Gien Watson ◽  
Paul D. Dorotich
Keyword(s):  
Effective Mass ◽  
Spring Stiffness ◽  
Mass Ratio ◽  
Characteristic Modeling ◽  
Effective Mass Ratio ◽  
Local Stiffness

The characteristic modeling parameters (spring stiffness and effective mass ratio) were determined experimentally for a Maxiflex “B” board. The results indicated that the Maxiflex “B” board was substantially less stiff than a Duraflex board. Most of this decrease in stiffness is a result of the added second taper in the Maxiflex “B” board. Calculations, based on theory, revealed that the perforations in the Maxiflex “B” board reduced the local stiffness over the end region of the board by an additional 10%. As a result of its greater compliancy, the Maxiflex board also had an effective mass ratio that was greater than that of the Duraflex. It was clear from these experiments that the acknowledged superiority of the Maxiflex “B” board over the Duraflex could be attributed directly to the increased compliancy found in the Maxiflex “B” board.

Theoretical Modeling of TLD With Different Tank Geometries Using Linear Long Wave Theory

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
X. Deng ◽  
M. J. Tait
Keyword(s):  
Effective Mass ◽  
Virtual Work ◽  
Damping Ratio ◽  
Wave Theory ◽  
Mass Ratio ◽  
Flat Bottom ◽  
Tuned Liquid Dampers ◽  
Long Wave ◽  
Effective Mass Ratio ◽  
Energy Dissipated

This study focuses on the modeling of tuned liquid dampers (TLDs) with triangular-bottom, sloped-bottom, parabolic-bottom, and flat-bottom tanks using the linear long wave theory. The energy dissipated by damping screens is modeled theoretically utilizing the method of virtual work. In this proposed model, only the fundamental sloshing mode is considered, and the assumption of small free surface fluid response amplitude is made. Subsequently, the equivalent mechanical properties including effective mass, natural frequency, and damping ratio of the TLDs, having different tank geometries, are compared. It is found that the normalized effective mass ratio values for a parabolic-bottom tank and a sloped-bottom tank with a sloping angle of 20 deg are larger than the normalized effective mass ratio values for triangular-bottom and flat-bottom tanks. An increase in the normalized effective mass ratio indicates that a greater portion of the water inside the tank participates in the sloshing motion. The derived equivalent mechanical models for the TLD tank geometries considered in this study can be used for the preliminary design of structural-TLD systems.

A Percolation Equation for Modeling Experimental Results for Continuum Percolation Systems

2001 ◽  
Vol 699 ◽  
Author(s):  
D.S. McLachlan ◽  
C. Chiteme ◽  
W.D. Heiss ◽  
Junjie Wu
Keyword(s):  
Experimental Data ◽  
Ac Conductivity ◽  
Volume Fraction ◽  
Power Laws ◽  
Second Order ◽  
Experimental Results ◽  
Analytical Equation ◽  
Scaling Properties ◽  
First Order ◽  
Dc And Ac Conductivity

AbstractThe standard percolation equations or power laws, for dc and ac conductivity (dielectric constant) are based on scaling ansatz, and predict the behaviour of the first and second order terms, above and below the percolation or critical volume fraction (øc), and in the crossoverregion. Recent experimental results on ac conductivity are presented, which show that these equations, with the exception of real σm above øc and the first order terms in the crossover region, are only valid in the limit σi/σc = 0, where for an ideal dielectric σi=ωε0εr.A single analytical equation, which has the same parameters as the standard percolation equations, and which, for ac conductivity, reduces to the standard percolation power laws in the limit σi(ωε0εr)/σc = 0 for all but one case, is presented. The exception is the expression for real σm below øc, where the standard power law is always incorrect. The equation is then shown to quantitatively fit both first and second order dc and ac experimental data over the entire frequency and composition range. This phenomenological equation is also continuous, has the scaling properties required at a second order metal-insulator and fits scaled first order dc and ac experimental data. Unfortunately, the s and t exponents that are necessary to fit the data to the above analytical equation are usually not the simple dimensionally determined universal ones and depend on a number of factors.

DC and AC Conductivity Study of Basalt Glasses Containing High Concentrations of Na+ Ions

Silicon ◽  
2018 ◽  
Vol 10 (5) ◽  
pp. 2153-2160 ◽  
Author(s):  
M. Y. Hassaan ◽  
A. G. Mostafa ◽  
H. A. Saudi ◽  
M. A. Ahmed ◽  
Hatem M. H. Saad
Keyword(s):  
Ac Conductivity ◽  
Dc And Ac Conductivity ◽  
Na Ions ◽  
High Concentrations ◽  
Basalt Glasses
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