THE ATTENUATION OF HIGH-AMPLITUDE WAVES IN ROCKS

1964 ◽  
Vol 42 (3) ◽  
pp. 526-534
Author(s):  
R. F. Mereu
Keyword(s):  
Absorption Coefficient ◽  
Seismic Energy ◽  
High Amplitude ◽  
Absorption Coefficients ◽  
The Absolute ◽  
Coefficients Of Absorption

The pin-contactor method was modified so that it could be used to measure coefficients of absorption of high-amplitude waves in cylinders of rocks and metals. Experiments performed with granite, marble, and aluminum showed that the coefficients of absorption for marble and aluminum for pressures below 100 kb are more than three times that for granite. Also, for pressures greater than 22 kb the absorption coefficient for marble is more than twice that for pressures below this level. It should be emphasized that the absolute values of the absorption coefficients found in these experiments depend on the geometry; however, the relative values indicate the extent of the differences in the properties of the rocks. The compressibilities of both marble and granite were found to be constant for pressures in the 2 to 100 kb range. The results of these experiments and similar ones could lead to a better understanding of how the energy of explosions can be coupled into seismic energy more efficiently.

The Electrically Controlled Birefringence Measurement Influence of Liquid Crystal Caused by Absorption Effect in Infrared Region

2014 ◽  
Vol 875-877 ◽  
pp. 467-471
Author(s):  
Ning Wang ◽  
Xiao Xia Li
Keyword(s):  
Liquid Crystal ◽  
Absorption Coefficient ◽  
Approximate Method ◽  
Nematic Liquid Crystal ◽  
Infrared Region ◽  
Interference Method ◽  
Absorption Coefficients ◽  
Absorption Effect ◽  
Ordinary Light

The electrically controlled birefringence of nematic liquid crystal BL-009 was measured by polarized interference method. The influence of LC absorption effect, the birefringence variation, is discussed in this paper. The experiments results showed the influence to birefringence is big in infrared region. Not only the birefringence value is greatly different with that of unconsidering absorption effect, but also the gradient changing of birefringence curves is obvious. Furthermore, the electrically controlled birefringences of two conditions are compared when the absorption coefficients of ordinary light and the extraordinary light are nearly same and greatly different. The analysis demonstrated the approximate method of absorption coefficient is feasible.

The Use of Reverse Mirage Spectroscopy to Determine the Absorption Coefficient of Liquid Methanol at CO2 Laser Wavelengths

1989 ◽  
Vol 43 (1) ◽  
pp. 148-153 ◽  
Author(s):  
Dane Bićanić ◽  
Siegfried Krüger ◽  
Paul Torfs ◽  
Bruno Bein ◽  
Frans Harren
Keyword(s):  
Absorption Coefficient ◽  
Co2 Laser ◽  
Probe Beam ◽  
Laser Emission ◽  
Wavelength Region ◽  
Experimental Setup ◽  
Absorption Coefficients ◽  
Experimental Conditions ◽  
Liquid Samples

An experimental setup for performance of reverse mirage spectroscopy at CO2 laser wavelengths on liquid samples having high values of absorption coefficients is described. One and the same liquid is used as both the absorbing and deflecting medium. The Rosencwaig-Gersho theory has been applied, and the choice of experimental conditions that would enable determination of absorption coefficient β from the magnitude of photothermal signals measured at two different probe beam distances (probing locations) is discussed. The usefulness of this technique (essentially not inhibited by the requirements imposed on the sample's thickness) is tested on methanol having absorption coefficients β close to 300 cm−1 in the wavelength region covered by CO2 laser emission.

scholarly journals Absorption Corrections for X-Ray Fluorescence Analysis of Environmental Samples

1975 ◽  
Vol 19 ◽  
pp. 381-391 ◽  
Author(s):  
F. Bazan ◽  
N. A. Bonner
Keyword(s):  
Absorption Coefficient ◽  
Environmental Samples ◽  
Fluorescence Analysis ◽  
Coherent Scattering ◽  
Absorption Coefficients ◽  
X Ray

The discovery of a very simple and useful relationship between the absorption coefficient of a particular element and the ratio of incoherent to coherent scattering by the sample containing the element is discussed. By measuring the absorption coefficients for a few elements in a few samples, absorption coefficients for many elements in an entire set of similar samples can be obtained.

Complex seismic trace analysis of thin beds

Geophysics ◽  
1984 ◽  
Vol 49 (4) ◽  
pp. 344-352 ◽  
Author(s):  
James D. Robertson ◽  
Henry H. Nogami
Keyword(s):  
Instantaneous Frequency ◽  
Trace Analysis ◽  
Frequency Tuning ◽  
Seismic Energy ◽  
High Amplitude ◽  
Opposite Polarity ◽  
Peak Period ◽  
Seismic Wavelet ◽  
Porous Sandstone ◽  
Seismic Sections

Displays of complex trace attributes can help to define thin beds in seismic sections. If the wavelet in a section is zero phase, low impedance strata whose thicknesses are of the order of half the peak‐to‐peak period of the dominant seismic energy show up as anomalously high‐amplitude zones on instantaneous amplitude sections. These anomalies result from the well‐known amplitude tuning effect which occurs when reflection coefficients of opposite polarity a half period apart are convolved with a seismic wavelet. As the layers thin to a quarter period of the dominant seismic energy, thinning is revealed by an anomalous increase in instantaneous frequency. This behavior results from the less well‐known but equally important phenomenon of frequency tuning by beds which thin laterally. Instantaneous frequency reaches an anomalously high value when bed thickness is about a quarter period and remains high as the bed continues to thin. In this paper, complex trace analysis is applied to a synthetic model of a wedge and to a set of broadband field data acquired to delineate thin lenses of porous sandstone. The two case studies illustrate that sets of attribute displays can be used to verify the presence and dimensions of thin beds when definition of the beds is not obvious on conventional seismic sections.

Finite element sound field analysis on measurement of absorption coefficient in a reverberation room -Relationships between inclination of walls and measurement results-

2021 ◽  
Vol 263 (1) ◽  
pp. 5571-5577
Author(s):  
Reiji Tomiku ◽  
Noriko Okamoto ◽  
Toru Otsuru ◽  
Shun Iwamoto ◽  
Shoma Suzuki
Keyword(s):  
Finite Element ◽  
Absorption Coefficient ◽  
Sound Field ◽  
Field Analysis ◽  
Reverberation Time ◽  
Absorption Coefficients ◽  
Sound Fields ◽  
Measurement Results ◽  
Coefficient Measurement ◽  
Absorption Performance

The absorption coefficients in a reverberation room are most representative measure for evaluating absorption performance of architectural materials. However, it is well known that measurement results of the coefficient vary according to a room shape of the measurement and area of the specimen. Numerical analyses based on wave acoustics are effective tools to investigate these factors on absorption coefficient measurement in reverberation room. In this study, sound fields for the measurement of absorption coefficient in reverberation room are analyzed by time domain finite element method (TDFEM). This study shows effectiveness of the analysis for investigation on causes of variation in the measurement results and improvement methods of the measurement. First, some measurement sound fields for absorption coefficient in reverberation rooms the walls of which are incline or decline are analyzed by the TDFEM. Next, reverberation times in each sound fields are calculated from the results obtained by TDFEM and the absorption coefficients are evaluated from the reverberation time of the room with and without specimen. Finally, the relationships among room shape, degree of inclination of the wall, the sound absorption coefficient of the specimen, frequencies and the measurement absorption coefficient are investigated.

Absorption Coefficients of Inelastic Dynamic X-Ray Diffraction

2014 ◽  
pp. 483-502
Keyword(s):  
Absorption Coefficient ◽  
Inelastic Scattering ◽  
Waller Factor ◽  
Time Dependent ◽  
X Ray Diffraction ◽  
Absorption Coefficients ◽  
X Ray ◽  
Charge Current ◽  
Dispersion Equations ◽  
Debye Waller Factor

The X-ray inelastic scattering phenomena during the time-dependent perturbations are described with the aid of dynamical dispersion equations coupled with charge current in the Maxwell equations towards the appearance of the Debye-Waller factor driving the absorption coefficient, either for inelastic thermal diffusion and the Compton scattering, respectively.

Mass Absorption Coefficient Measurements Using Thin Films

1969 ◽  
Vol 13 ◽  
pp. 632-638 ◽  
Author(s):  
P. Lublin ◽  
P. Cukor ◽  
R. J. Jaworowski
Keyword(s):  
Thin Films ◽  
Absorption Coefficient ◽  
Mass Absorption Coefficient ◽  
Absorption Coefficients ◽  
Electron Probe Analysis ◽  
Mass Absorption ◽  
Probe Analysis ◽  
Absorption Correction ◽  
Thin Foils ◽  
Metal Organic

For quantitative electron probe analysis, the raw intensity ratios must be corrected to take into account deviations due to absorption, fluoresecnce and electron beam penetration. The major correction is usually the absorption correction, so that for best results, accurate mass absorption coefficients are required. Many tables of absorption coefficients are calculated by interpolation or extrapolation from available measured values, and therefore new measurements are required for increased reliability. The region which requires the most attention for present-day probe analysis is the 2 to 10 Å range.Thin foils of the lighter metals are available for mass absorption coefficient measurements, but heavy metal foils, which must be extremely thin, are not obtainable, A method has been developed to prepare thin films of heavy metals on a suitable substrate by pyrolytic decomposition of metal organic compounds.

Measurement of Mass Absorption Coefficients Using Compton-Scattered Cu Radiation in X-ray Diffraction Analysis

1990 ◽  
Vol 34 ◽  
pp. 325-335 ◽  
Author(s):  
Steve J. Chipera ◽  
David L. Bish
Keyword(s):  
Chemical Composition ◽  
Solid State ◽  
Absorption Coefficient ◽  
Mass Absorption Coefficient ◽  
X Rays ◽  
X Ray Diffraction ◽  
Absorption Coefficients ◽  
Solid State Detector ◽  
X Ray ◽  
Mass Absorption

AbstractThe mass absorption coefficient is a useful parameter for quantitative characterization of materials. If the chemical composition of a sample is known, the mass absorption coefficient can be calculated directly. However, the mass absorption coefficient must be determined empirically if the chemical composition is unknown. Traditional methods for determining the mass absorption coefficient involve measuring the transmission of monochromatic X-rays through a sample of known thickness and density. Reynolds (1963,1967), however, proposed a method for determining the mass absorption coefficient by measuring the Compton or inelastic X-ray scattering from a sample using Mo radiation on an X-ray fluorescence spectrometer (XRF). With the recent advances in solid-state detectors/electronics for use with conventional powder diffractometers, it is now possible to readily determine mass absorption coefficients during routine X-ray diffraction (XRD) analyses.Using Cu Kα radiation and Reynolds’ method on a Siemens D-500 diffractometer fitted with a Kevex Si(Li) solid-state detector, we have measured the mass absorption coefficients of a suite of minerals and pure chemical compounds ranging in μ/ρ from graphite to Fe-metal (μ/ρ = 4.6-308 using Cu Kα radiation) to ±4.0% (lσ). The relationship between the known mass absorption coefficient and the inverse count rate is linear with a correlation coefficient of 0.997. Using mass absorption coefficients, phase abundances can be determined during quantitative XRD analysis without requiring the use of an internal standard, even when an amorphous component is present.

scholarly journals Linear and Nonlinear Intersubband Optical Properties of Direct Band Gap GeSn Quantum Dots

Nanomaterials ◽  
2019 ◽  
Vol 9 (1) ◽  
pp. 124 ◽  
Author(s):  
Mourad Baira ◽  
Bassem Salem ◽  
Niyaz Madhar ◽  
Bouraoui Ilahi
Keyword(s):  
Quantum Dots ◽  
Refractive Index ◽  
Absorption Coefficient ◽  
Electron Energy ◽  
Energy State ◽  
Total Absorption ◽  
Absorption Coefficients ◽  
Third Order ◽  
Index Changes ◽  
Total Absorption Coefficient

Intersubband optical transitions, refractive index changes, and absorption coefficients are numerically driven for direct bandgap strained GeSn/Ge quantum dots. The linear, third-order nonlinear and total, absorption coefficients and refractive index changes are evaluated over useful dot sizes’ range ensuring p-like Γ-electron energy state to be lower than s-like L-electron energy state. The results show strong dependence of the total absorption coefficient and refractive index changes on the quantum dot sizes. The third order nonlinear contribution is found to be sensitive to the incident light intensity affecting both total absorption coefficient and refractive index changes, especially for larger dot sizes.

THEORY OF TRANSLATIONAL ABSORPTION IN GASES

1961 ◽  
Vol 39 (1) ◽  
pp. 189-204 ◽  
Author(s):  
J. D. Poll ◽  
J. Van Kranendonk
Keyword(s):  
Absorption Coefficient ◽  
Infrared Absorption ◽  
Dipole Moments ◽  
Gas Mixtures ◽  
Absorption Coefficients ◽  
Monatomic Gas

The theory of translational infrared absorption in gases is developed. Invariant expressions for the integrated absorption coefficients are derived. The absorption coefficients are expanded in powers of the density, and the binary absorption coefficients are expressed in terms of a model for the induced pair dipole moments. Monatomic gas mixtures, diatomic gases, and diatomic–monatomic gas mixtures are considered in detail. As an application the binary absorption coefficient of the translational band of hydrogen is calculated.

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