bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radiales Druckprofil in einem magnetoplasmadynamischen Wasserstoff-Lichtbogen
Authors: Mccann T. E. , Bohn W. L. 
Published: February 2015

Abstract
The calculation of the radial pressure profile of an MPD-arc as a function of the ambient pres-sure and the superimposed magnetic field as has been developed in a previous paper is extended to the 13-moments approximation. The higher moments approximation introduces additional thermomagnetic forces and changes significantly the structure of the velocity-dependant part of the external viscous forces. While the Hall-effect and the mass flow are practically unaffected by the higher approximation, as far as their influence on the radial pressure profile is concerned, the ambipolar diffusion leads to an appreciably smaller pressure increase than the 5-moments theory. Qualitative differences of the two approximations are discussed beyond the scope of pressure profiles via the generalized Ohm's law. Quantitative results for a partially as well as for a fully ionized plasma are shown in diagrams. The importance of thermomagnetic forces (especially the Nernst effect) for MPD-arcs is clearly pointed out.
Thermotransport of solutes in liquid silver *,**
Authors: Bhat B. N. , Swalin R. A. 
Published: February 2015

Abstract
Thermotransport studies have been made for liquid silver which contained trace amounts of gold, antimony and sulfur. Capillaries containing silver and homogeneously distributed solute were sub­jected to a temperature gradient and solute redistribution at the stationary state was determined by sectioning and radiotracer technique. The net heat of transport was obtained from the slope of a plot of the logarithm of solute concentrations versus reciprocal of absolute temperature. The segregation was rather small for Au but pronounced for Sb and S. Values of Q* for Au, Sb and S are 1688 cal/mole, -6768 cal/mole and -29,000 cal/mole respectively. The experimental results are discussed in terms of the various factors which contribute to the heat of transport.
Thermal Diffusion in Mixtures of Alcohols and Aromatic Hydrocarbons
Authors: Belton P. S. , Tyrrell H. J. V. 
Published: February 2015

Abstract
The thermal diffusion factors observed for these systems vary considerably with concentration, and frequently show a change in sign at some concentration. New data on ethanol-toluene mixtures show that the sign and magnitude of the separation of the components in a thermal gradient are also strongly dependent on the mean temperature of the system. These observations, together with earlier ones on similar systems, can be given a semi-quantitative interpretation in terms of a shift in the average degree of association of the alcohol along the temperature gradient.
Anharmonicity in Diffusion * *
Authors: Flynn C. P. 
Published: February 2015

Abstract
It is emphasized that anharmonic effects are important in determining the parameters describing diffusion processes at elevated temperatures in crystals. The relevance of anharmonicity to the reaction rate and the dynamical theories of diffusion, and to models of defect formation and migra­tion, is discussed. A comparison is made between the theoretical results and some collected experi­mental data pertaiining mainly to ionic crystals
On the Dielectric Constant of Zirconia and Lime-zirconia
Authors: Sanesi Manlio , Cremante Giorgio , Pizzini Sergio , Wagner Vittoriano 
Published: February 2015

Abstract
The dielectric constant of monoclinic zirconia and of lime-zirconia (up to a CaO content of 20% mole) has been measured at 25 °C by the powder method. For pure ZrO2 the D.C. is 13.5, while for lime-zirconia a non linear dependence on the CaO content has been observed in the measured range, with a maximum at about 14% mole CaO. The results are discussed, in the light of the authors previous density data for the same systems, in terms of the width of the homo­geneity range of the solid solutions
Investigation of Excited States of Helium Atoms in a Stationary PIG-Discharge
Authors: Drawin H. W. , Klan F. , Ringler H. 
Published: February 2015

Abstract
Spectral line intensities emitted by a quiescent PIG-discharge have been measured and the population densities up to a principal quantum number n = 24 have been derived from them. The experimentally determined population densities have been compared with theoretical ones calculated on the basis of a collisional-radiative model in which one accounts for electron and atom collisions. I t is shown that even in the case of different electron and atom temperatures, Te and Ta, an evaluation of the Boltzmann plot at medium and moderately high quantum numbers always leads to the electron temperature, whereas the Saha-Eggert equation for the same states may yield incorrect electron densities. The theoretical calculations predict an inflection of the slope of the Boltzmann plot from Te to Ta for very highly excited states. For the plasma para­ meters under which the PIG-discharge was operated (ne ≅ 2.5 × 1012 cm-3, Te ≅ 1200°K, n0 ≅ 1.5 × 1015 cm-3, 300°K) the change of the slope should become visible for states having principal quantum numbers n > 18. Due to the large experimental error bars it was not possible to check this behaviour.
Experimental Effects of R. F. Irradiation on N. M. R. Lines in Solids
Authors: Haupt J. , Steenwinkel R. van 
Published: February 2015

Abstract
In this paper measurements about the steady state of both Zeeman and dipolar energies of a spin system submitted to r. f. irradiation are presented. These experiments were performed in order to provide a quantitative check of the existing theories. Two samples are investigated, polycrystalline benzene in which relaxation is caused by molecular motions and a monocrystal of CaF2 + 0.01% Ce+++ impurities. For both samples the regions of extreme narrowing and of large T1Z/T1D ratio are investigated. The results are discussed in terms of Provotorov's and Redfield's theories. While in the extreme narrowing region fairly good agreement is obtained some restriction to the Provotorov theory is observed in the region of long correlation times.
Activation Volume Measurements
Authors: Beyeler Michele , Lazarus David 
Published: February 2015

Abstract
The determination of the activation volume of diffusion is one of the best methods for the in­vestigation of the relaxation of atoms or ions around defects. This paper discusses two experimental techniques for the determination of the activation volume for diffusion, by studying the effect of hydrostatic pressure on tracer diffusion and on ionic conductivity. Such experiments require a very clean hydrostatic pressure environment, accurate temperature control and measurement, and well defined specimen geometry. The difficulties encountered during such experiments are discussed. Results are given for the activation volumes of diffusion in beryllium and in sodium chloride.
Magnetic Behavior of Europium Silicates Using Nuclear Gamma Resonance Spectroscopy
Authors: Kalvius G.M. , Shenoy G.K. 
Published: February 2015

Abstract
The ferromagnetic transition temperature, the quadrupole interaction, the hyperfine magnetic field, and the isomer shift have been measured in Eu2SiO4 and Eu3SiO5 using the 21.6 keV nuclear gamma resonance in 151Eu. The isomer shifts found (-0.6 mm/sec for Eu2SiO4 and +0.1 mm/sec for Eu3SiO5 against EuS) are less negative than the values typical for other ionic Eu2+ compounds. The magnetic hyperfine fields (280 kOe for Eu2SiO4 and 240 kOe for Eu3SiO5) are much lower than the Eu2+ free ion value. A brief qualitative discussion of these hyperfine parameters is given. A rough correlation between the isomer shift and the transition temperature for various divalent Eu compounds is indicated. The effect of trivalent of the silicates is demonstrated.
Mössbauer Isomer Shifts and Hyperfine Splitting of the 145.4 keV γ-rays of 141Pr
Authors: Kapfhammer W.H. , Maurer W. , Wagner F.E. , Kienle P.E. 
Published: February 2015

Abstract
The Mössbauer scattering of the 145.4 keV γ-rays of 141Pr was observed in a number of praseodymium compounds. From the isomer shifts between trivalent and tetravalent fluorine compounds the value Δ/(r2) = + 12 · 10-3 fm2 was derived for the change of the nuclear charge radius. The magnetic moment of the 145.4 keV state, μ7/2= (2.8 ± 0.2) μN, was deduced from the magnetic hyperfine pattern observed with scatterers of antiferromagnetic PrO2 .
Messung kohärenter Streulängen mit Christiansen-Filtern für Neutronenstrahlung
Authors: Koester L. , Knopf K. 
Published: February 2015

Abstract
Measurements of Neutron-Scattering-Amplitudes using the Christiansen-Filter- Technique By means of Christiansen-Filters it is possible to make use of the high accuracy achieved for the scattering amplitudes of liquids also for solids in form of powders. We investigated the scattering law for the small angle scattering of Neutrons by Christiansen-Filters and found a good agreement between theory and experiment. Using powders of several elements we could measure the scattering amplitudes of the elements with an uncertainty within ± 0.2% to ± 1%.
We got for the bound atoms of
Al: a = (3.449±0.009) F; Nb: a = (7.11 ± 0.04 ) F;
Cr: a = (3.532 ± 0.010) F; Te: a= (5.43 ± 0.04 ) F;
Sb: a = (5.641 ± 0.012) F; and Ta: a = (6.91 ± 0.07) F.
Si: a = (4.159±0.006) F;
Bestimmung von (n n'γ)-Querschnitten für 14,4 MeV-Neutronen im Massebereich A = 46 — 88
Authors: Breunlich W. , Stengel G. , Vonach H. 
Published: February 2015

Abstract
Es wurde eine systematische Untersuchung der (n,n'γ) -Querschnitte für 14 MeV-Neutronen an gg-Kernen im Massenbereich A = 46 - 88 durchgeführt und die Querschnitte für die Anregung des ersten 2+-Niveaus für 19 Kerne im genannten Massenbereich wurden gemessen. Die Ergebnisse können durch das statistische Modell der Kernreaktionen befriedigend erklärt werden.
Einfluß von Neutronenbestrahlung bei 4 °K auf den Schermodul von Kupfer, Aluminium und Platin
Authors: Wenzl Helmut , Kerscher Franz , Fischer Veit , Ehrensperger Klaus , Papathanassopoulos Konstantinos 
Published: February 2015

Abstract
The change of the shearmodulus of pure polycrystalline Al, Cu and Pt due to reactor neutron irradiation at 4 °K has been studied. The shearmodulus was determined by measuring the vibrational frequencies of a helical spring in two different modes (between 50 and 300 Hz) together with internal friction and electrical resistance. Large relative decreases of the shearmodulus ΔG/G per molar fraction c of Frenkel defects were found, namely ΔG/Gc - 47, - 39, - 67 for Al, Cu and Pt, respectively. The absolute values are much larger than expected from lattice theory. The effects cannot be explained by a relaxation of the defects.
Representation of Symmetries and Observables in Functional Hilbert Space. I.
Authors: Rieckers A. 
Published: February 2015

Abstract
A representation of symmetry transformations motivated by the functional formulation of quantum field theory is rigorously discussed in a functional Hilbert space. The set of generating functionals is equipped with an inner product by means of the Friedrichs-Shapiro-integral and completed to an Hilbert space. Unitarity, continuity, and reducibility are investigated for the symmetry operations in this space. Also non-unitary transformations are considered.
Electronic Excitation and Thermodynamic Properties of High Temperature Gases
Authors: Capitelli M. , Ficocelli E. 
Published: February 2015

Abstract
Different cut-off criteria of partition functions have been utilized in order to evaluate the con­tribution of electronic excitation to thermodynamic properties of high temperature gases (5000 °K to 35 000 °K, 10-2-10 atm).
It is shown that properties of single species are strongly affected by the cut-off criterion adopted, i. e. the contribution of electronic excitation to these properties is important.
It is also shown that the reported absence of this contribution to total enthalpies and specific heats of plasmas is the result of an almost complete compensation between "reactional" and "frozen" terms which are all dependent on electronic excitation.
Thermodynamic Investigations of Thin Liquid Layers Between Solid Surfaces II. Water Between Entirely Hydroxylated Fused Silica Surfaces
Authors: Peschel G. , Adlfinger K. H. 
Published: February 2015

Abstract
By a special method the disjoining pressure of water caused by a molecular long range orienta­tion between fully hydroxylated and highly polished fused silica surfaces at different temperatures (0-74 °C) and plate distances ≦ 1000 Å was determined. Four marked maxima were found at about 15°, 32°, 45°, and 61 °C for not too small plate distances. At these temperatures many authors have detected anomalies in the temperature dependence of some physical properties of water. This evidence is discussed in regard to our results which particularly imply thermodynamic quantities derived from the aqueous surface zone.
Thermodynamic Investigations of Thin Liquid Layers Between Solid Surfaces III. Benzene Between Differently Polar Fused Silica Surfaces
Authors: Peschel G. , Adlfinger K. H. 
Published: February 2015

Abstract
Former measurements showed that benzene exhibits a disjoining pressure in extremely thin layers between fused silica plates in a temperature range just above the melting point. An extended theory for evaluating the disjoining pressure and various thermodynamic quantities of the liquid surface zone which displays a molecular long range orientation leads to results which indicate a small structural transition range at about 12 - 13 °C in bulk benzene. The splitting effect is more pronounced in layers adjacent to fully hydroxylated surfaces since in this case the benzene mole­cules in the first adsorbed layer are more tightly bound than in the case of surfaces entirely free from hydroxyl groups.
Temperature Dependence of Electrical and Thermal Resistivities of Noble Metals
Authors: Semwal B. S. , Mehrotra P. K. , Mehrotra K. N. 
Published: February 2015

Abstract
The electrical and thermal resistivities of noble metals copper, silver and gold have been de­termined at different temperatures in the free electron approximation using Sharma and Joshi's model for the phonon dispersion relations. A modified Houston's method is used to evaluate the formidable integral over the scattering vector. The normal and Umklapp contributions to the resistivity are considered separately from the conservation laws of wave vector. The theoretical and experimental resistivity curves are found to be of similar nature, but the agreement is not detailed. The Lorentz numbers of noble metals deduced from theoretical and experimental resistivity data show considerable deviation from Wiedemann-Franz law.
Thermodynamik heterogener Gasgleichgewichte I. Freie Bildungsenthalpie ΔGB
0 der Verbindungen in den Wolfram-Halogen-Systemen
Authors: Neumann G. M. , Knatz W. 
Published: February 2015

Abstract
Zur Beurteilung der chemischen Transportreaktionen in den Wolfram-Halogen Systemen werden nach dem Verfahren der 3. Ulichschen Näherung Gleichgewichtskonstanten Kp und freie Bildungs­ enthalpien ΔGB° der Verbindungen WF2 , WF4 , WF5 , WBr2 , WBr4 und der hypothetischen Verbindungen WJ, WJ2 , WJ4 , WJ5, WJ6 bis zur Temperatur des flüssigen Wolframs ermittelt.
Im Zusammenhang mit bekannten Daten zeigt sich, daß in den Systemen Wolfram-Chlor und Wolfram-Brom die Reaktionen über die Verbindungen WX4 und WX2 ablaufen, während im System Wolfram-Fluor daneben die Verbindungen WX5 und WX6 eine Rolle spielen. Die Daten des Systems Wolfram-Jod zeigen, daß die reinen Wolfram-Jod-Verbindungen energetisch nicht stabil sind. Die in der Literatur beschriebenen experimentellen Befunde von der Nichtexistenz dieser Verbindungen werden dadurch vom Standpunkt der Thermodynamik bestätigt.
Über die elektronischen Energieniveaus des N-Isopropylcarbazols und seiner Radikalionen 2. Teil: Elektronenspinresonanzspektren
Authors: Klöpffer W. , Kaufmann G. , Naundorf G. 
Published: February 2015

Abstract
Well resolved spectra have been obtained from the radical anion of N-isopropylcarbazole (NIPCA). The splitting parameters have been evaluated by simulation of the spectrum. It is shown that in accordance with HMO calculations the spin density at the nitrogen atom is very small. The poorly resolved NIPCA·+ spectrum points to a high spin density at the nitrogen atom. The mean square zero field splitting parameter of NIPCA is identical with that reported for carbazole.
Self-Diffusion, Conductivity and Transport Numbers in Alkali Halide Single Crystals
Authors: Beniere Franqois , Beniere Michelle , Chemla Marius 
Published: February 2015

Abstract
The self-diffusion coefficients of the anions and cations have been measured in pure and doped NaCl and KCl crystals, together with the ionic conductivity. The experimental results give evidence for migration mechanisms via free cation and anion vacancies and vacancy pairs. Analysis of the complete set of diffusion data leads to the determination of the entropy and enthalpy of formation and migration of these defects.
In a second part, the diffusion coefficients via free vacancies are compared with the conductivity data in order to investigate the validity of the Nernst-Einstein relation. This relation is found to be verified within 2%, in NaCl as well as in KCl, no appreciable correlation effect being detected.
The Existence Diagram — A Useful Theoretical Tool in Applied Physics
Authors: Ecker G. 
Published: February 2015

Abstract
The complexity of theoretical work in physics applications often forces severe neglections and crude approximations. Insufficient experimental knowledge of important parameters increases the uncertainty. In this situation the E-diagram method still allows to arrive at useful results through controlled choice of the approximations and sensible limitation of the aims. Choosing “unidirected” deviations only, existence limits can be calculated which restrict the existence of the system to a narrow region - the existence area - of the coordinate plane of variables under consideration. The example of the vacuum arc cathode demonstrates the procedure and its suitablility.
On the Senftleben-Beenakker Electric Effect in Gaseous Ammonia
Authors: Levi A.C. , Tommei G.E. 
Published: February 2015

Abstract
The viscosity of gaseous ammonia in the presence of a static homogeneous electric field is calculated using the Waldmann-Snider equation. Special attention is paid to the field dependence of the effect which is strongly influenced by molecular inversion. The latter causes a coupling of tensors of different rank in J in the expansion of the distribution matrix, thereby leading to an infinite set of equations which is solved numerically by a limiting procedure. The effect has a complicated dependence on pressure p and field E but to a good approximation turns out to depend on E/p a t pressures high with respect to an inversion pressure (about 5 atm for NH3, 300 torr for ND3) and, in agreement with the experiments, on E2/p at low pressures.
Untersuchung des 5p2P3/2-Terms im Silber I-Spektrum durch Resonanzstreuung von Licht in elektrischen und magnetischen Feldern
Authors: Bucka H. , Einfeld D. , Ney J. , Wilken J. 
Published: February 2015

Abstract
Using separated isotopes the hyperfine structure of the 5p 2P3/2-state in Ag I-spectrum was investigated by scattering the resonance line on an atomic beam in parallel magnetic and electric fields. With the theoretical positive sign of the Stark-constant β, the shift of the Heydenburg- and level-crossing-signals with electric fields can be explained by the following parameters:
Ag (107) : A = - (32,4 ± 0.5) Mc/sec ,
Ag (109): A - - (37,3 ± 0.8) Mc/sec ,
β (2P3/2) = (5.15 ± 0.15) (kc/sec) (kV/cm) -2 ,
τ (2p3/2) = (6.3 ± 0.6 ) · 10-9 sec.
Kinetic Theory for a Dilute Gas of Particles with "Spin"
Authors: Hess S. , Waldmann L. 
Published: February 2015

Abstract
The Senftleben-Beenakker effect of the viscosity of dilute polyatomic gases is investigated theoretically for the case where an alternating magnetic field parallel to the usual static field is present. The starting point is a set of transport-relaxation equations obtained from the kinetic equation for the one-particle distribution by application of the moment method. The transport-relaxation equations are solved for the viscosity problem and the relevant viscosity coefficients averaged over many periods of the oscillating field are calculated as functions of the frequency of the alternating field and of the magnitudes of both magnetic fields. The importance of the obtained results for the dynamic behaviour of the thermomagnetic gas torque (Scott effect) is discussed.
Lösungskalorimetrische Bestimmung der Energieaufnahme von naßvermahlenem Aluminiumpulver
Authors: Wagendristel A. , Berger R. 
Published: February 2015

Abstract
Gitterdefekte erhöhen den Energieinhalt eines Festkörpers. Dies zeigt sich bei chemischen Umsetzungen in einem zusätzlichen Beitrag zur Reaktionsenthalpie. Im folgenden wird über die Veränderung der Lösungswärme von Aluminiumpulver durch eine Sdiwingmahlbehandlung mit steigender Mahldauer berichtet. Die Zunahme der Lösungswärme entspricht den bei einer Wärmebehandlung ermittelten Werten der Speicherenergie1.
Messungen der Bildfehler eines elektrostatischen Sektorfeldes / Measurement of Image Aberrations of an Electrostatic Sector Field
Authors: Bäuml Alfred 
Published: February 2015

Abstract
The ion-optical properties of a cylinder-condenser (sector angle φ = 50° and curvature radius of the middle equipotential surface r0 = 100mm) are investigated by an experimental ray-tracing technique.
A narrow electron beam entering the field under a known angle and at a known place is observed on the exit side of the field by means of a luminescent screen combined with a special micro-scope. The measurement of the lateral distances of this ray from the central beam in several distances behind the exit field-boundary yields the information about the imaging properties of the sector field. The analysis of the measurements indicates the existence of a third-order angular aberration. The experimentally determined values of second-order α-, u-, and δ-aberration-coefficients do not differ substantially from the theoretical ones.
Das Verhältnis der Flußdichten thermischer und intermediärer Neutronen in der Umgebung von Neutronenquellen im Wasser
Authors: Bortfeldt H. J. , Matzke M. 
Published: February 2015

Abstract
Measuring the cadmium-ratio as function of the distance from (α,n) -neutron sources in water we found a clearly distinguishable maximum followed by a small decrease with increasing distance. This behaviour can be explained by a calculation in diffusion approximation using special source terms.