Drift velocity of holes in germanium and silicon

1979 ◽  
Vol 57 (8) ◽  
pp. 1233-1238 ◽  
Author(s):  
H. Nakagawa ◽  
S. Zukotynski
Keyword(s):  
Experimental Data ◽  
Drift Velocity ◽  
Coupling Constants ◽  
Phonon Coupling ◽  
Key Factor ◽  
Maxwellian Distribution Function ◽  
Valence Bands ◽  
P Type ◽  
Theoretical Results ◽  
Good Agreement

The displaced Maxwellian distribution function as it applies to semiconductors with lattice limited scattering is discussed. It is shown that good agreement between theoretical results and experimental data for the drift velocity can be obtained if the phonon coupling constants are lowered somewhat from their correct values. Calculations are presented for p-type germanium and silicon and it is shown that the key factor that must be considered in both materials is the non-parabolicity of the valence bands.

Explanation of the Influence of Inflow Air Content on the Lift of Cavitating Hydrofoils

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Eduard Amromin
Keyword(s):  
Experimental Data ◽  
Theoretical Study ◽  
Lift Coefficient ◽  
Cavity Surface ◽  
Air Bubbles ◽  
Incoming Flow ◽  
Fluid Density ◽  
Air Content ◽  
Theoretical Results ◽  
Good Agreement

According to several known experiments, an increase of the incoming flow air content can increase the hydrofoil lift coefficient. The presented theoretical study shows that such increase is associated with the decrease of the fluid density at the cavity surface. This decrease is caused by entrainment of air bubbles to the cavity from the surrounding flow. The theoretical results based on such explanation are in a good agreement with the earlier published experimental data for NACA0015.

In-Plane Vibrations of Thick Circular Rings With T or I Cross Sections

1979 ◽  
Vol 46 (2) ◽  
pp. 470-472
Author(s):  
H. Lecoanet ◽  
J. Piranda
Keyword(s):  
Experimental Data ◽  
Eigenvalue Problem ◽  
Cross Section ◽  
Cross Sections ◽  
Rectangular Cross Section ◽  
Circular Rings ◽  
Theoretical Results ◽  
Good Agreement

This paper deals with the problem of eigenfrequencies and eigenvectors for rings whose cross section may be decomposed in basic rectangular cross sections. The solution is derived from a solution of the in-plane eigenvalue problem for rectangular cross-section thick rings. A good agreement between theoretical results and experimental data is obtained.

Analysis of Thermal Effects in Hydrodynamic Bearings

1986 ◽  
Vol 108 (2) ◽  
pp. 219-224 ◽  
Author(s):  
R. Boncompain ◽  
M. Fillon ◽  
J. Frene
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Thermal Effects ◽  
Reynolds Equation ◽  
Energy Equation ◽  
Heat Transfer Equation ◽  
Reversed Flow ◽  
Theoretical Results ◽  
Generalized Reynolds Equation ◽  
Good Agreement

A general THD theory and a comparison between theoretical and experimental results are presented. The generalized Reynolds equation, the energy equation in the film, and the heat transfer equation in the bush and the shaft are solved simultaneously. The cavitation in the film, the lubricant recirculation, and the reversed flow at the inlet are taken into account. In addition, the thermoelastic deformations are also calculated in order to define the film thickness. Good agreement is found between experimental data and theoretical results which include thermoelastic displacements of both the shaft and the bush.

Thermal Behavior and Friction in Journal Bearings

1970 ◽  
Vol 92 (3) ◽  
pp. 373-380 ◽  
Author(s):  
Al. Nica
Keyword(s):  
Experimental Data ◽  
Thermal Behavior ◽  
Heat Dissipation ◽  
Journal Bearings ◽  
Friction Torque ◽  
Operating Characteristics ◽  
Lubricant Flow ◽  
Theoretical Predictions ◽  
Theoretical Results ◽  
Good Agreement

This paper deals with friction and the field of temperature in the lubricant film of journal bearings. Theoretical results regarding the thermal behavior are checked with experimental data and good agreement is found. Emphasis is put on the variation of temperature and lubricant flow with the operating characteristics of the bearing and it is seen that theoretical predictions for minima of friction torque are backed by temperature measurements. Further on, the friction torque and the mechanism of heat dissipation in bearings are dealt with, in order to verify the assumptions used in the calculation schemes. The means of efficiently cooling the bearing are also discussed, as well as the part played by the divergent zone in this process.

scholarly journals Added Mass and Damping of a Vibrating Rod in Confined Viscous Fluids

1976 ◽  
Vol 43 (2) ◽  
pp. 325-329 ◽  
Author(s):  
S. S. Chen ◽  
M. W. Wambsganss ◽  
J. A. Jendrzejczyk
Keyword(s):  
Experimental Data ◽  
Experimental Study ◽  
Cylindrical Shell ◽  
Closed Form Solution ◽  
Added Mass ◽  
Form Solution ◽  
Viscous Fluids ◽  
Series Of Experiments ◽  
Theoretical Results ◽  
Good Agreement

This paper presents an analytical and experimental study of a cylindrical rod vibrating in a viscous fluid enclosed by a rigid, concentric cylindrical shell. A closed-form solution for the added mass and damping coefficient is obtained and a series of experiments with cantilevered rods vibrating in various viscous fluids is performed. Experimental data and theoretical results are in good agreement.

scholarly journals First-Principles Calculations of the Structural, Electronic and Optical Properties of Yttrium-Doped SnO2

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Nabil Beloufa ◽  
Youcef Chechab ◽  
Souad Louhibi-Fasla ◽  
Abbes Chahed ◽  
Samir Bekheira ◽  
...  
Keyword(s):  
Optical Properties ◽  
Near Infrared ◽  
First Principles Calculations ◽  
Electronic And Optical Properties ◽  
Level Shifts ◽  
Type Semiconductor ◽  
Direct Band ◽  
P Type ◽  
Theoretical Results ◽  
Good Agreement

Abstract We use FP-LAPW method to study structural, electronic, and optical properties of the pure and Y-doped SnO2. The results show that by Y doping of SnO2 the band gaps are broadened, and still direct at Γ-point. For pure SnO2 material, the obtained values of the direct band gap are 0.607 eV for GGA-PBE and 2.524 eV for GGATB-mBJ, respectively. This later is in good agreement with the experimental data and other theoretical results. The Fermi level shifts into the valence band and exhibits p-type semiconductor character owing mainly from the orbital 4d-Y. Additionally, the calculated optical properties reveal that all concentrations are characterized by low reflectivity and absorption via wavelength λ (nm) in the visible light and near-infrared (NIR) ranges, which leads to a redshift in the optical transparency.

Non-Destructive Electrical Techniques as Means for Understanding the Basic Mechanisms of Electromigration

1994 ◽  
Vol 337 ◽  
Author(s):  
A. Scorzoni ◽  
I. De Munari ◽  
H. Stulens
Keyword(s):  
Experimental Data ◽  
High Resolution ◽  
Mechanical Stress ◽  
Diffusion Model ◽  
Physical Mechanism ◽  
Relative Resistance ◽  
Resistance Change ◽  
Non Destructive ◽  
Theoretical Results ◽  
Good Agreement

ABSTRACTIn this paper results of recently developed high resolution resistometric electromigration techniques will be described, with particular attention to the behaviour of narrow, near-bamboo metal lines. After a discussion on recent theoretical results published in the literature, a diffusion model correlating mechanical stress and electromigration will be adopted to describe experimental results of relative resistance change both during and after electromigration. The good agreement between experimental data and simulations must not hide that something must still be understood about the physical mechanism leading to resistance changes during electromigration experiments.

J/ψ PRODUCTION IN A GLAUBER MONTE CARLO FRAMEWORK

2010 ◽  
Vol 25 (05) ◽  
pp. 1009-1018 ◽  
Author(s):  
HONG-MIN WANG ◽  
ZHAO-YU HOU ◽  
BEN-AI ZHANG ◽  
XIAN-JING SUN
Keyword(s):  
Experimental Data ◽  
Monte Carlo ◽  
Center Of Mass ◽  
Nuclear Modification Factor ◽  
Center Of Mass Energy ◽  
Modification Factor ◽  
Energy Formula ◽  
Theoretical Results ◽  
Monte Carlo Framework ◽  
Good Agreement

By means of a Glauber Monte Carlo framework, the J/ψ production at RHIC energies is studied with the EKS98, EPS09 and HKN07 shadowing parameters. With a χ2 analysis of the experimental data given by PHENIX, a significant dependence of the absorption cross-section, σ abs , on the J/ψ-nucleon center-of-mass energy, [Formula: see text], is revealed with the HKN07 shadowing, but an unconspicuous dependence is shown with the EKS98 and EPS09 shadowing. In this paper, the nuclear modification factor Rd Au vs y, pT and N coll are also calculated and the theoretical results are in good agreement with the experimental data.

scholarly journals Theory determination of $$\varvec{\bar{B}\rightarrow D^{(*)}\ell ^-\bar{\nu }}$$ form factors at $$\varvec{\mathcal {O}(1/m_c^2)}$$

2020 ◽  
Vol 80 (2) ◽  
Author(s):  
Marzia Bordone ◽  
Martin Jung ◽  
Danny van Dyk
Keyword(s):  
Experimental Data ◽  
Light Cone ◽  
Sum Rules ◽  
Form Factors ◽  
Longitudinal Polarization ◽  
Polarization Fraction ◽  
Theoretical Results ◽  
Good Agreement ◽  
Lepton Flavour

Abstract We carry out an analysis of the full set of ten $$\bar{B}\rightarrow D^{(*)}$$B¯→D(∗) form factors within the framework of the Heavy-Quark Expansion (HQE) to order $$\mathcal {O}\left( \alpha _s,\,1/m_b,\,1/m_c^2\right) $$Oαs,1/mb,1/mc2, both with and without the use of experimental data. This becomes possible due to a recent calculation of these form factors at and beyond the maximal physical recoil using QCD light-cone sum rules, in combination with constraints from lattice QCD, QCD three-point sum rules and unitarity. We find good agreement amongst the various theoretical results, as well as between the theoretical results and the kinematical distributions in $$\bar{B}\rightarrow D^{(*)}\lbrace e^-,\mu ^-\rbrace \bar{\nu }$$B¯→D(∗){e-,μ-}ν¯ measurements. The coefficients entering at the $$1/m_c^2$$1/mc2 level are found to be of $$\mathcal {O}(1)$$O(1), indicating convergence of the HQE. The phenomenological implications of our study include an updated exclusive determination of $$|V_{cb}|$$|Vcb| in the HQE, which is compatible with both the exclusive determination using the BGL parametrization and with the inclusive determination. We also revisit predictions for the lepton-flavour universality ratios $$R_{D^{(*)}}$$RD(∗), the $$\tau $$τ polarization observables $$P_\tau ^{D^{(*)}}$$PτD(∗), and the longitudinal polarization fraction $$F_L$$FL. Posterior samples for the HQE parameters are provided as ancillary files, allowing for their use in subsequent studies.

QCD SUM RULES FOR THE $Z_c^+(3900)$ STATE

2014 ◽  
Vol 26 ◽  
pp. 1460069 ◽  
Author(s):  
F. S. NAVARRA ◽  
J. M. DIAS ◽  
M. NIELSEN ◽  
C. M. ZANETTI
Keyword(s):  
Experimental Data ◽  
Sum Rules ◽  
Coupling Constants ◽  
Tetraquark State ◽  
Point Function ◽  
Qcd Sum Rules ◽  
Decay Widths ◽  
Structure Formula ◽  
Good Agreement

We use the QCD sum rules to study the recently observed charmonium-like structure [Formula: see text] as a tetraquark state. We evaluate the three-point function and extract the coupling constants of the [Formula: see text] and [Formula: see text] vertices and the corresponding decay widths in these channels. The results obtained are in good agreement with the experimental data and supports to the tetraquark picture of this state.

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