De Haas – van Alphen effect and Fermi surface of the intermetallic compound PtSn

1970 ◽  
Vol 48 (10) ◽  
pp. 1151-1160 ◽  
Author(s):  
W. N. Cathey ◽  
P. T. Coleridge ◽  
J.-P. Jan
Keyword(s):  
Intermetallic Compound ◽  
Fermi Surface ◽  
Cross Sections ◽  
Experimental Results ◽  
The Other ◽  
Platinum Atom ◽  
Spin Splitting ◽  
Approximate Determination ◽  
Formula Unit

Extremal cross sections of the Fermi surface of the intermetallic compound PtSn (NiAs structure) have been determined by means of the de Haas – van Alphen effect. The Fermi surface proposed here is similar to that found in isostructural AuSn by Edwards et al. Several of the frequencies have been inverted to yield the profile of the corresponding sheets of the Fermi surface. An approximate determination of the dimensions of the other sheets shows that the observed Fermi surface encloses 4.60 ± 0.27 electrons per formula unit; this suggests that one or several sheets of the Fermi surface containing 0.6 d-band holes per platinum atom have remained undetected. Some cyclotron masses have been measured and to explain all the features of the experimental results, it is necessary to invoke spin splitting with a g factor different from 2, and to postulate magnetic breakdown.

scholarly journals Diffusion and chemical reaction velocity as joint factors in determining the rate of uptake of oxygen and carbon monoxide by the red blood corpuscle

1932 ◽  
Vol 111 (769) ◽  
pp. 1-36 ◽  
Keyword(s):  
Carbon Monoxide ◽  
Cross Sections ◽  
The Other ◽  
Blood Corpuscle ◽  
Reaction Velocity ◽  
Two Fluids ◽  
Mixing Chamber ◽  
Haemoglobin Solution ◽  
Moving Fluid

In a paper on this subject published four years age, Hartridge and Roughton (1927) described some preliminary experiments upon the rate of uptake of oxygen and carbon monoxide by the red blood corpuscle, the observations being made by means of their reaction velocity technique (Hartridge and Roughton, 1922–1927). The general principles of the method were as follows. Through one lead of the apparatus a suspension of reduced corpuscles in saline was forces into the mixing chamber, whilst through the other lead was forced a solution of oxygen (or carbon monoxide) in saline. The two fluids mixed in the mixing chamber within 0·001 second or less and then travelled down the observation tube. Determination of the percentage of oxyhæmoglobin (or carboxyhæmoglobin) in the moving fluid at various cross sections of the observation tube was made by means of the reversion spectroscope, these measurements, together with a knowledge of the rate of flow of the fluid down the observation tube, giving the necessary data for plotting the rate of uptake of O 2 or CO by the corpuscles against time. The most interesting feature of the results was the much slower uptake of O 2 by hæmoglobin in the intact corpuscle as compared with the of O 2 by hæmoglobin in laked solution as previously recorded by Hartridge and Roughton (1925). In the corpuscle experiments the time scale had to be expressed in hundredths of a second instead of in thousandths of a second as in the hæmoglobin solution experiments ( vide fig. 2 of Hartridge and Roghton, 1927). Confirmatory results by somewhat different technique have been obtained lately by Dirken and Mook (1931). These will be referred to again later.

Quantitative Determimatioh of Sulfur, Chlorine, Potassium, Calcium, Scandium and Titanium in Aqueous Solutions by Radioisotopic Excited Fluorescent Spectrometer and by Conventional X-Ray Spectrometer

1970 ◽  
Vol 14 ◽  
pp. 102-126 ◽  
Author(s):  
Frank L. Chan ◽  
W. Barclay Jones
Keyword(s):  
Particle Size ◽  
Aqueous Solutions ◽  
Experimental Results ◽  
The Other ◽  
X Rays ◽  
Helium Atmosphere ◽  
X Ray ◽  
Effect Of Particle Size ◽  
The One

AbstractAn x-ray spectrometer with experimental results is herewith described using a radiosotope source Fe55 having a halflife of 2.6 years. As a result of the disintegration, the managanese x-rays are capable of exciting fluorescent x-rays of such elements as sulfur, chlorine, potassium, calcium, scandium and titanium in aqueous solutions. These elements with the Ka wavelengths ranging from 5.3729 Å to 2.7496 Å may be designated as between the very soft x-rays on the one hand and the hard x-rays on the other. The x-ray spectrometer presently described has achieved a resolution of 136 ev, FWHM.Simultaneously, these elements have also been quantitatively determined by conventional x-ray fluorescent spectrometers. Since one of the spectrometers is designed to operate in vacuum as well as in helium or air, determination of sulfur, potassium and calcium were carried out in vacuum. Determination of chlorine was carried out in a helium atmosphere, Calcium, scandium and titanium were determined in air with an air-path spectrometer.In the present study aqueous solutions containing these elements were used. The use of aqueous solutions has the inherent advantages of being homogeneous and free from effect of particle size.

Etude des mouvements de molécules linéaires en phase liquide par analyse du profil des bandes d'absorption infrarouge.: II. Bande v3 du sulfure de carbonyle

1972 ◽  
Vol 50 (2) ◽  
pp. 217-225 ◽  
Author(s):  
A. M. Bize ◽  
J. Soussen-Jacob ◽  
J. Vincent-Geisse ◽  
D. Legay ◽  
J. P. Perchard
Keyword(s):  
Potential Barrier ◽  
Correlation Functions ◽  
Carbonyl Sulfide ◽  
Experimental Results ◽  
The Other ◽  
Band Width ◽  
Saturated Hydrocarbons ◽  
Rotational Effect ◽  
The Mean

The band width and profile of v3 mode of carbonyl sulfide (OCS) dissolved in about 30 solvents have been examined. The study of temperature broadening permits the separation of the vibrational and rotational effects and the determination of the potential barrier to rotation. Correlation functions have been plotted from the experimental results; the mean squared torques acting on carbonyl sulfide in various solvents have been calculated from the second and the fourth moments. The obtained results bear evidence of a dominant rotational effect for solutions in saturated hydrocarbons while, for the other solvents, vibrational broadening proves important.

Uniaxial strain derivatives of the Fermi surface of copper

1983 ◽  
Vol 61 (2) ◽  
pp. 177-187 ◽  
Author(s):  
D. W. Ruesink ◽  
J. M. Perz
Keyword(s):  
Experimental Study ◽  
Tensile Stress ◽  
Fermi Surface ◽  
Shear Strain ◽  
Cross Sections ◽  
The Other ◽  
Quantum Oscillations ◽  
Self Consistent ◽  
Torque Values ◽  
Derivatives Of

From a comprehensive experimental study of quantum oscillations in magnetostriction and torque, values have been deduced for all nonvanishing tetragonal and angular shear strain derivatives for the five principal extremal cross sections of the Fermi surface of copper, viz., the neck and belly normal to [111], the dogsbone normal to [110], and the rosette and belly normal to [001]. It is found that the neck is most sensitive to angular shear strain, whereas the bellies are most affected by uniform dilation. For the other orbits the magnitudes of shear and dilation derivatives are comparable.The results are self-consistent and agree with the experimental tensile stress results of Shoenberg and Watts. Earlier magnetostriction results for the neck obtained by Aron and by Slavin can be brought into agreement with the present data by recalculating the former using the now accepted value for the neck effective mass. The present experimental derivatives are in qualitative agreement with the theoretical values calculated by Lee, except for the tetragonal shear derivative of the [001] belly, for which the theoretical value is about 50% higher than the experimental one. This discrepancy is not fully understood.

The determination of cross-sections for the quenching of resonance radiation of metal atoms. IV. Results for lithium

1968 ◽  
Vol 306 (1486) ◽  
pp. 413-421 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Cross Section ◽  
Cross Sections ◽  
Hollow Cathode ◽  
Alkali Metals ◽  
Resonance Radiation ◽  
The Other ◽  
Fluorescence Technique ◽  
Metal Atoms

The flame fluorescence technique has been used to study the fluorescence of lithium in sets of isothermal hydrogen-oxygen flames diluted with each of the gases argon, nitrogen and carbon dioxide. The measurements have given the following values (Å 2 ) for the quenching cross-sections, σ 2 , of lithium in the 2 p 2 P state: σ 2 H 2 = 5⋅2, σ 2 H 2 O ═ 1⋅9, σ 2 N 2 ═ 6⋅75, σ 2 CO ═ 12⋅6, σ 2 CO 2 ═ 9⋅2, σ 2 Ar ≼ 0⋅3. The cross-section is defined as the square of the distance between centres of colliding species. These values are compared with those previously reported (Jenkins 1966, 1968) for the other alkali metals and their interpretation discussed. Details of the high intensity hollow cathode lamp used as a source of lithium resonance radiation are also given.

Application of methods for analysing combinations of wheelset sizes and switch elements to determine the size of gutters of check-rail assemblies

2021 ◽  
pp. 3-9
Author(s):  
B. E. Glyuzberg ◽  
◽  
A. A. Loktev ◽  
V. V. Korolev ◽  
V. S. Kuskov ◽  
...  
Keyword(s):  
Cross Sections ◽  
Accurate Method ◽  
The Other ◽  
Conditional Probabilities ◽  
Rail Wear ◽  
Method Of Determination ◽  
Train Operation ◽  
Motion Paths ◽  
The One

The paper considers methods for analysis of size combinations of wheelsets and elements of switches that are used at determination of dimensions of gutters for check-rail assemblies. The method of limit combinations, from the one side, doesn’t guarantee a reliable train operation on crossing assemblies in real operation, but, from the other side, it makes unreasonably strict demands to the design of the assembly. In order to eliminate the contradictions the paper proposes to use a method of probable compositions that allows not only solving an issue of limited safe dimensions of gauge and gutters, but also determining repeatability of impacts on check-rails in the most loaded cross sections and repeatability of motion paths of wheels on crossing. However, while using this method the authors have revealed a number of contradictions between calculated results and real operation. They show that it is possible to avoid the contradictions by the use of conditional probabilities method that allows calculating probabilities of phenomena for specific size combinations of gauge and gutters. As a result, the authors have concluded that it is the most accurate method of determination of permissible dimensions for gauge and gutters on switches. With the use of the method the authors have determined the maximal values of check-rail wear for straight track made of SP special profiles in conditions of nonexceedance of «impact effect» in bent part of the check-rail for switches with various angles.

Determination of K shell absorption parameters for some lanthanides using the X-ray attenuation method

2015 ◽  
Vol 93 (12) ◽  
pp. 1532-1540 ◽  
Author(s):  
F. Akman ◽  
R. Durak ◽  
M.R. Kaçal
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Experimental Results ◽  
Secondary Source ◽  
X Rays ◽  
Strength Parameters ◽  
X Ray ◽  
Total Attenuation ◽  
First Time

The total attenuation cross section at the K edge, absorption jump ratio, jump factor, Davisson–Kirchner ratio, and oscillator strength parameters for the K shell were determined by measuring the total attenuation cross sections around the K edge for Pr, Nd2O3, and Sm. The measurements were performed in a secondary excitation geometry using the Kα2, Kα1, Kβ1, and Kβ2 X-rays (in the region from 31.817 to 55.293 keV) from different secondary source targets excited by the 59.54 keV γ-photons from an 241Am annular source. It is the first time that the Davisson–Kirchner ratio values have been determined for present samples. The experimental results were compared with the theoretically calculated and other available experimental results.

Determination of the spin-splitting factor gc for Landau levels from the first three harmonics in the de Haas–van Alphen effect

1976 ◽  
Vol 54 (24) ◽  
pp. 2445-2455 ◽  
Author(s):  
A. V. Gold ◽  
P. W. Schmor
Keyword(s):  
Band Structure ◽  
Fermi Surface ◽  
Landau Levels ◽  
Spin Splitting ◽  
Structure Model ◽  
The Third ◽  
Splitting Factor ◽  
Dimensionless Ratio ◽  
Band Structure Model

A simple and convenient method is proposed for extracting the spin-splitting factors gc associated with extremal orbits around the Fermi surface from knowledge of the amplitudes Ar of the first three harmonics in the de Haas–van Alphen effect. In the approach suggested here, the quantity of prime interest is the dimensionless ratio α = A22/A1A3, which is independent of both the detailed shape of the Fermi surface and the Dingle temperature. Information about the relative phases of the harmonics allows corrections to be made for the Shoenberg magnetic interaction.In a first application of this three-harmonic method, the dHνA waveform has been studied in disk-shaped samples of Pb using a sensitive magnetoresistive-probe technique, and gc has been determined for the orbits ν and ν′ on the third-zone electron surface. We have also attempted to calculate the splitting factors within the framework of the 4 OPW band-structure model of Anderson, O'Sullivan, and Schirber. However, the simplification of using 4 OPW's throughout the Brillouin zone is found to lead to serious errors and inconsistencies as far as these differential magnetic quantities are concerned.

Determination of the Recombination Processes in Copper Ternary Chalcopyrites by Phototransport Measurements

1996 ◽  
Vol 426 ◽  
Author(s):  
Y. Lubianmker ◽  
G. Bitton ◽  
I. Balberg ◽  
O. Resto ◽  
S. Z. Weisz
Keyword(s):  
Level Structure ◽  
Experimental Results ◽  
The Other ◽  
Recombination Level ◽  
Recombination Processes ◽  
General Recombination ◽  
Level Model ◽  
Ternary Chalcopyrites ◽  
Two Level Model

AbstractWe have measured the phototransport properties of CuGaSe2 films as a function of temperature. The simplest model which is consistent with all the experimental results consists of two recombination levels, one of which is donor-like and the other is acceptor-like. This model is similar to the symmetrical two-level model, which we have recently suggested for CuInS2 films. We thus conclude that this model, with slight variations, represents the general recombination level structure in all copper ternary chalcopyrites.

scholarly journals Textile wing fabric for emergency response UAS

2020 ◽  
Vol 71 (04) ◽  
pp. 321-326
Author(s):  
ADRIAN SĂLIȘTEAN ◽  
CARMEN MIHAI
Keyword(s):  
Emergency Response ◽  
Mechanical Characteristics ◽  
Statistical Data ◽  
Breaking Strength ◽  
Air Permeability ◽  
Experimental Results ◽  
The Other ◽  
Shape Stability ◽  
International Testing

The fabrics used to manufacture parachutes and paragliders must have several specific characteristics: the mass of fabric per unit of surface must be low while the other physical-mechanical characteristics (the axial breaking strength load, the relative and absolute elongation, the tear resistance of the fabric and the assemblies, air permeability) must have high values. The paper deals with the analysis of qualitative aspects of several parachute fabrics that are used as a baseline in the development of a novel fabric. The results of experiments have materialized in statistical data, diagrams and graphs and their interpretation leads to the determination of the fabric variant that best meets the requirements of the destination. The destination is a patent pending inflatable wing design that utilizes a single skin construction and solid reinforcements in the sewing for shape stability. It is worth noting that the experimental results were compared with values indicated in specific international testing norms.

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