Relativistic calculation of the K-LL Auger spectrum

1959 ◽  
Vol 249 (1259) ◽  
pp. 555-573 ◽  
Keyword(s):  
Auger Spectrum ◽  
Relativistic Effects ◽  
Fluorescence Yield ◽  
Numerical Calculations ◽  
Approximate Estimate ◽  
Radiative Transitions ◽  
Relativistic Calculation ◽  
Electronic Computers ◽  
Good Agreement

Extensive relativistic calculations have been carried out for the K -L L Auger spectrum of mercury based on Moller’s semi-classical treatment for the interaction of radiation with electrons. Numerical calculations using electronic computers give, for the relative intensities and position of the different lines of the spectrum, values in very good agreement with observation and remove the discrepancies obtained earlier by Massey & Burhop for some of them. It is found that relativistic effects increase the Auger transitions by about 84% and decrease the radiative transitions by about 75%. An approximate estimate for the k-series fluorescence yield w k of 0.961 is also obtained.

scholarly journals A General Expression for the Stagnant Thermal Conductivity of Stochastic and Periodic Structures

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
X. Bai ◽  
C. Hasan ◽  
M. Mobedi ◽  
A. Nakayama
Keyword(s):  
Thermal Conductivity ◽  
General Expression ◽  
Metal Foam ◽  
Solid Angle ◽  
Periodic Structures ◽  
Three Dimensional ◽  
High Thermal Conductivity ◽  
Numerical Calculations ◽  
The One ◽  
Good Agreement

A general expression has been obtained to estimate thermal conductivities of both stochastic and periodic structures with high-solid thermal conductivity. An air layer partially occupied by slanted circular rods of high-thermal conductivity was considered to derive the general expression. The thermal conductivity based on this general expression was compared against that obtained from detailed three-dimensional numerical calculations. A good agreement between two sets of results substantiates the validity of the general expression for evaluating the stagnant thermal conductivity of the periodic structures. Subsequently, this expression was averaged over a hemispherical solid angle to estimate the stagnant thermal conductivity for stochastic structures such as a metal foam. The resulting expression was found identical to the one obtained by Hsu et al., Krishnan et al., and Yang and Nakayama. Thus, the general expression can be used for both stochastic and periodic structures.

Viscous Dissipation in Laminar Water Flows in Micro-Tubes

2007 ◽  
Author(s):  
In-Hwan Yang ◽  
Mohamed S. El-Genk
Keyword(s):  
Experimental Data ◽  
Viscous Dissipation ◽  
Temperature Rise ◽  
Experimental Results ◽  
Numerical Calculations ◽  
Analytical Expression ◽  
Water Flows ◽  
Good Agreement

Numerical calculations are performed to investigate the effect of viscous dissipation on the temperature rise and friction numbers for laminar water flows in micro-tubes. The calculated values are compared with those determined from reported experimental data for glass and diffused silica micro-tubes (D = 16 – 101 μm and L/D = 625 – 1479). The results confirm a definite slip at the wall with slip lengths of ∼ 0.7 μm and 1.0 μm, which decrease the friction number and the temperature rise in the micro-tubes, but their effect gradually diminishes as either D or L/D increases. The friction number decreases exponentially as D decreases and, to a lesser extent, as L/D increases. The effect of L/D on the friction number is insignificant for micro-tube diameters ≤ 20 μm. For D > 400 μm, the friction number approaches that of Hagen-Posieuille of 64 for macro-tubes when L/D > 1500, but approaches higher values at smaller L/D. The dimensionless analytical expression developed for calculating the friction number and the temperature rise for water flows in micro-tubes is in good agreement with both the numerical and experimental results.

scholarly journals DECAY CONSTANTS OF HEAVY–LIGHT MESONS IN THE RELATIVISTIC QUARK MODEL

2002 ◽  
Vol 17 (13) ◽  
pp. 803-807 ◽  
Author(s):  
D. EBERT ◽  
R. N. FAUSTOV ◽  
V. O. GALKIN
Keyword(s):  
Quark Model ◽  
Light Quark ◽  
Relativistic Effects ◽  
Relativistic Quark Model ◽  
Sum Rule ◽  
Decay Constants ◽  
Model Predictions ◽  
Relativistic Treatment ◽  
Light Mesons ◽  
Good Agreement

The decay constants of pseudoscalar and vector heavy–light mesons are calculated in the framework of the relativistic quark model with the completely relativistic treatment of the light quark. It is argued that relativistic effects play a significant role. Good agreement of the model predictions with recent lattice and QCD sum rule calculations as well as available experimental data are found.

A New Slip Theory of Plasticity

1974 ◽  
Vol 41 (3) ◽  
pp. 587-592 ◽  
Author(s):  
T. H. Lin ◽  
Y. M. Ito ◽  
C. L. Yu
Keyword(s):  
Experimental Data ◽  
Equilibrium Condition ◽  
Numerical Calculations ◽  
Thin Wall ◽  
Face Centered Cubic ◽  
Stress Strain ◽  
Elastic Range ◽  
Theory Of Plasticity ◽  
Face Centered ◽  
Good Agreement

A slip theory is presented for the calculation of the incremental stress-strain relations of a face-centered cubic polycrystal such as aluminum and its alloys, from its experimental uniaxial curves. This theory satisfies the conditions of equilibrium, condition of continuity of displacement as well as the slip characteristics of the component crystals. Numerical calculations based on this theory give results which are in good agreement with known experimental data on thin wall cylinders subject to different ratios of incremental axial and torsional loadings after being compressed beyond the elastic range.

Hyperfine structure of Eu I

1965 ◽  
Vol 289 (1416) ◽  
pp. 81-96 ◽  
Keyword(s):  
Theoretical Analysis ◽  
Hyperfine Structure ◽  
Relativistic Effects ◽  
Interaction Constant ◽  
Tensor Operator ◽  
Quadrupole Moments ◽  
Core Polarization ◽  
The Core ◽  
Least Squares Fit ◽  
Good Agreement

A theoretical analysis is made of the hyperfine structure of the twelve levels of Eu I 4 f 7 ( 8 S ) 6 s 6 p using intermediate-coupled eigenfunctions obtained from a least-squares fit of the energies of the levels. Relativistic effects for the 6 p electron are calculated throughout by tensor-operator techniques. Good agreement is obtained with the observed A values, treating as parameters the polarization of the core (by the f electrons) and the hyperfine interaction constant of the 6 s electron. The magnitude of the core polarization is related to data on Eu I 4 f 7 ( 8 S ) 6s 2 , Euii 4 f 7 ( 8 s ) 6 s , and Eu III 4 f 7 ( 8 S ). The hyperfine-structure anomalies also fall into a consistent pattern. The observed B values are related to quadrupole moments of 151 Eu and 153 Eu.

On the swimming of a flexible plate of arbitrary finite thickness

1964 ◽  
Vol 20 (1) ◽  
pp. 1-33 ◽  
Author(s):  
J. P. Uldrick ◽  
J. Siekmann
Keyword(s):  
Experimental Data ◽  
Finite Thickness ◽  
Numerical Calculations ◽  
Flexible Plate ◽  
Two Dimensional ◽  
Present Contribution ◽  
Fish Propulsion ◽  
Special Cases ◽  
Good Agreement

This paper studies the effect of profile thickness on the propulsive forces generated by the swimming of a two-dimensional fish. Comparison of numerical calculations with reported experimental data shows good agreement and demonstrates a decrease of thrust with increasing thickness. Previous two-dimensional linearized theories on fish propulsion dealing with the motion of an infinitesimally thin hydrofoil are included in the present contribution as special cases.

Role of Non-Radiative Transitions in X-RAY Analysis

1990 ◽  
Vol 48 (2) ◽  
pp. 10-11
Author(s):  
János L. Lábár
Keyword(s):  
Excited Atom ◽  
Fluorescence Yield ◽  
Initial State ◽  
Radiative Process ◽  
X Ray ◽  
Radiative Processes ◽  
Radiative Transitions ◽  
The Given ◽  
Electron Shells

Radiative and non-radiative transitions present alternative ways for the excited atom to reduce its energy when the initial state is an atom singly ionised in one of its inner electron shells. Since the fluorescence yield gives the probability that the empty state in the inner (sub)shell is filled in by a radiative process, it seems that the generated x-ray intensities are independent of the non-radiative rearrangements from the point on where the value of fluorescence yield is given for the (sub)shell in question. In that way the intensity of an x-ray line would solely be dependent on the ionisation probability of the given (sub)shell and on the rates of the radiative transitions (determining the relative intensities of the lines originating from the same subshell). That image involves that the non-radiative processes only influence the value of the fluorescence yield. For the simplest case i.e. for the K shell it is true.

Reflexionserscheinungen bei Torsions-Alfvén-Wellen in inhomogenen Magnetfeldern/ Reflection Phenomena of Torsional Alfvén Waves in Inhomogeneous Magnetic Fields

1975 ◽  
Vol 30 (12) ◽  
pp. 1594-1599
Author(s):  
E. Räuchle ◽  
P. G. Schüller
Keyword(s):  
Magnetic Fields ◽  
Experimental Results ◽  
Numerical Calculations ◽  
Wave Frequency ◽  
Field Inhomogeneity ◽  
Cylindrical Plasma ◽  
Spatially Inhomogeneous ◽  
Strong Reflection ◽  
Order Of Magnitude ◽  
Good Agreement

Abstract The propagation of torsional Alfen waves in a cylindrical plasma is investigated. Superimposed on the plasma are various types of spatially inhomogeneous axisymmetric magnetic fields. Characteristic examples are: in the direction of propagation spatially decreasing, increasing and periodically modulated magnetic fields. The wave lengths are of the same order of magnitude as the characteristic lengths of the inhomogeneities. Strong reflection is observed which depends on wave frequency and strength of the field inhomogeneity. There exists good agreement between experimental results and numerical calculations.

scholarly journals X-Ray Satellite Lines

1984 ◽  
Vol 86 ◽  
pp. 36-36
Author(s):  
J. Dubau
Keyword(s):  
Transition Probabilities ◽  
Relativistic Effects ◽  
Radiative Transition ◽  
Electron System ◽  
Great Accuracy ◽  
Atomic Data ◽  
X Ray ◽  
Spectroscopic Diagnostics ◽  
Radiative Transitions ◽  
Shell Vacancy

Satellite lines are typical features of X-ray spectra. They correspond to radiative transitions involving an inner-shell vacancy. The most studied satellite lines are of the - type, i.e., (ls–2p) transition.With the advent of Space Astronomy, X-ray spectra emitted by very hot solar plasma have been obtained. By a simple comparison of different spectra, it appears that, for highly ionized atoms, some satellite lines have intensities as large as resonance lines intensities and, more particularly, this is the case for the ls2n. – ls 2pn satellite lines of the 1s2 – ls2p resonance lines.The analysis of the different population mechanisms responsible for the satellite lines and resonance lines emission has shown that different spectroscopic diagnostics could be derived from line ratios only if atomic data of great accuracy were available. There exists nowadays different atomic data programs adapted to X-ray satellite lines. They have in common to give a great amount of data simultaneously: wavelengths, autoionization and radiative transition probabilities. They take into account correlation and relativistic effects.After tackling the simple 3-electron system, the programs give now appropriate data for more complex systems but this required large computers because the lines become blended. It is therefore impossible to limit the calculation to the most intense lines.

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