bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Finite-Amplitude Solution of the Self-Consistent Vlasov Equations
Authors: Lünow W. 
Published: February 2015

Abstract
The paper deals with the propagation of a finite-amplitude circularly polarized electromagnetic plane wave through a fully ionized hot collisionless plasma, composed of Q (≧1) types of ions and of electrons, as a strict solution of the non-relativistic self-consistent Vlasov equations within the scope of some given applicability criterions. A constant magnetic field and a constant total plasma stream, both parallel to the wave propagation direction, are allowed. Wave propagation and particle motion are separately discussed. Particularly, the possible existence of an anomalous wave, propagating with light speed through multi-component (Q>1) plasmas with arbitrary ratios plasmafrequency/wavefrequency, and the possible existence of multi-component plasmas with temperatures, far below thermonuclear temperatures, but under electromagnetically generated fusion conditions, are proved. The treated solution is of physical and astrophysical interest, likewise.
Double Shell Structure of the Periodic System of the Elements
Authors: Neubert D. 
Published: February 2015

Abstract
A new periodic system of the elements (PSE) is proposed which exhibits symmetry properties not apparent in the conventional arrangement of the elements. By discussing the solutions of the non-relativistic Schrödinger equation for the Coulomb problem it is shown that the PSE might be based on the filling of only four Coulomb shells as compared to the partial filling of up to eight shells in the conventional classification. On the other hand, the multiplicity of the states in the PSE appears to be four as compared to two due to spin in the hydrogen spectrum. A transformation of the PSE-spectrum into the hydrogen spectrum is possible by a rotation in quantum number space.
Photodissociation of H2 near Threshold Energies
Authors: Comes F. J. , Wenning U. 
Published: February 2015

Abstract
Measurements of the atomic hydrogen fluorescence (Lyα) yield important information on the dissociation behavior of molecular hydrogen under photon impact. Under certain assumptions the dissociation cross section of the molecule can be deduced from such experiments. By applying an appropriate electric field in the observation region those dissociations leading to the formation of metastable hydrogen atoms can be quantitatively determined. This information opens the possibility to describe the predissociation of the excited H2-molecules in the C-, D-and B″-states. The experiments show that the excited molecules in these particular states dissociate into H(1S) and H(2S) by configuration interaction with the B′-state.
Stoßbestimmte Grenzschicht in einem schwach ionisierten Plasma
Authors: Müller Karl Gerhard , Wahle Peter 
Published: February 2015

Abstract
In this work we develop a collision-dominated sheath model which includes the well known macroscopic models as extreme cases. We set up a description of the charge carriers with the help of the velocity distribution. In order to fulfil the microscopic boundary conditions at the wall we split up the velocity distributions into two parts. A basic set of new transport equations arises which differ from the usual equations by a correction term in the momentum transfer equations. Because of this splitting up of the velocity distribution we are able to take into account exactly specular reflection of the electrons at the wall. In a good approximation our results can also be obtained from the usual equations, if a suitably fitted factor is introduced into the electron boundary condition. at the wall.
On the Thermoelectric Power of Stabilized Zirconia
Authors: Pizzini S. , Riccardi C. , Wagner V. , Sinistri C. 
Published: February 2015

Abstract
Thermoelectric power of stabilized zirconia, at different CaO and MgO concentrations within the cubic phase, has been measured.
The results show a concentration dependence of the thermoelectric power which is preliminarly discussed.
The homogeneous part of the thermoelectric power, moreover, is discussed with the classical approach of irreversible thermodynamics.
Elektronenmikroskopische Untersuchungen an Tellur
Authors: Gottschalk H. , Kleinhenz K. , Wagner E. 
Published: February 2015

Abstract
In this paper a combined etching and electropolishing method to prepare thin Tellurium foils for transmission electron microscopy is described. This technique may be applied to massive sam-ples and is suitable for the preparation of thin foils at arbitrary points of deformed material. Speci-mens from deformed Tellurium single crystals were prepared in this way and examined in the electron microscope. Dislocations and grain boundaries were observed in these specimens.
Eine einfache Berechnung der Abbremsung schneller H-Atome durch kaltes H-Gas
Authors: Schäfer J. , Trefftz E. 
Published: February 2015

Abstract
In order to make a simple estimate of the thermalization of neutralized solar wind particles, classical elastic energy transfer cross sections are calculated for the H - H scattering process. A very simple approximation is also used for the macroscopic decelleration process. The estimated distance over which the hydrogen atoms lose half of their kinetic energy is 0.32 · 1018 cm and 24 · 1018 cm, for a starting velocity of 50 km/sec and 400 km/sec, resp., and for interstellar hydrogen density of 0.1 cm-3 . It appears that generally there is no thermalization shell around a star emitting a stellar wind.
Thermal Properties of Alkaline Earth Oxides II. Analysis of Experimental Results for MgO, CaO, SrO, and BaO
Authors: Gmelin E. 
Published: February 2015

Abstract
The heat capacities of MgO, CaO, SrO and BaO, reported in part I have been analysed in terms of the frequency spectrum of the lattice with the assumption that the effect of anharmonicity of the lattice may be neglected for T ≦ (ΘD/3).
Following the usual procedure the n-th moments of the frequency spectrum with n = - 3, -2, - 1, 0, 1 to 6 were calculated from the experimental data. From the low frequency expansion the apparent Debye characteristic temperature at 0 °K, Θ0, is calculated to be in good agreement with Θ0 (elast.), calculated from elasticity data. Also the limiting values at high temperatures,Θ∞, and the zero point energy, Ez, have been calculated.
A comparison between the heat capacity data, the elastic constants and thermal properties of these oxides and the alkali-halides suggest that the interatomic forces of the alkaline-earth-oxides are rather similar to those of the alkaline fluorides. But no specific divalent character has been detected for these oxides. An appreciable anharmonic effect is present for all oxides.
Massenspektrometrische Untersuchung der Sauerstoffverluste an heißen Rheniumoberflächen im Druckbereich 10–8 bis 10–4 Torr
Authors: Gross J. 
Published: February 2015

Abstract
The equivalent pumping speed of a heated rhenium surface for molecular oxygen has been measured. The surface was exposed to a constant oxygen gasflow and the oxygen pressure determined by means of a mass spectrometer. At a surface temperature of 2500 °K a pumping speed of Sn=7.6 ± 1.5 liters/sec cm2 was obtained for O2 . Because filaments of mass spectrometers have typically 5 to 10 mm2 heated surface this pumping speed may cause considerable errors during the calibration of the O2-sensitivity of mass spectrometers using rhenium filaments.
Relaxation des 5 1P1-Zustandes von Cadmium bei Stößen mit Edelgasatomen und Wasserstoffmolekülen
Authors: Pepperl R. 
Published: February 2015

Abstract
The linewidth of the Hanle effect signal of the orientation and alignment of the resonance level 5 1P1 of the cadmium isotop Cd114 is measured as a function of the pressure of various noble gases, of hydrogen and deuterium. The cross sections for broadening of the orientation and alignment signals due to atomic collisions are derived from the pressure dependence of the linewidth. The multipole depolarization-cross sections were found to be

In order to separate the depolarization effects from quenching effects in the case of hydrogen and deuterium polarization measurements of the resonance radiation were also undertaken. The alignment depolarization- and the quenching cross sections were found to
Lumineszenzuntersuchungen zum Problem der Energieübertragung in organischen Molekülkristallen
Authors: Belitz F. 
Published: February 2015

Abstract
From fluorescence spectra and decay times of single crystals of 2.3-dimethylnaphthalene, phenanthrene and p-terphenyl doped with one or two different types of fluorescence molecules (anthracene and, or tetracene) informations about the energy transfer processes are obtained. For doping concentrations smaller than 4·10-4 Mol/Mol the transfer by excitons is the main process. The dipole-dipole interaction over distances more than 80 Å (14 mean molecular distances) can be excluded. The mean travelling distance of the excitons in the three host lattices was found to be 250 - 300 mean molecular distances.
Notizen: Measurement of the Magnetic Moments of the Microsecond-isomers in 73As and 206Pb +
Authors: Quitmann D. , Jaklevic J. M. 
Published: February 2015

Abstract
The isomeric state of 73As (426 keV, 5.8 μsec) was produced and aligned by the reaction 71Ga (a,2n) in a liquid metal target. The anisotropics of the depopulating γ-rays were measured vs. the dc magnetic field applied perpendicular to the beam-detector plane. From the attenuation and rotation, we obtain g = + 1.03 ± 0.11. Limits of δ2 < 10-2 can be set to the multipole admixtures in both γ-transitions. The same technique was applied to the 123 μsee isomer of 206Pb (2200 keV) produced by 204Hg (a,2n). After estimating the relaxation time, g = - (0.035 ± 0.020) is obtained.
Notizen: Erzwungener Raman-Effekt an ausgedehnten Defektstrukturen in LiF
Authors: Heilmann G. 
Published: February 2015

Abstract
Raman-Effekt des idealen Kristallgitters von LiF tritt auf, wenn die 632,8 nm-Strahlung eines He-Ne-Lasers auf ausgedehnte Defektstrukturen mit Durchmessern in der Größenordnung von 10 ju und darüber fokussiert wird 1 . Die wichtigsten Merkmale dieser Spektren sind 1. das Auftreten von Linien, die Ein-, Zwei-und Drei-phononen-Prozessen zugeordnet werden können, 2. die geringe Intensität im Spektralbereich bis 1000 cm -1 , 3. das Verschwinden von Einzelheiten ihrer Struktur mit wachsender Intensität der anregenden Strahlung, das auf einen Schwellwert hindeutet, 4. ihr Fehlen in der vorwärts gestreuten Strahlung und 5. ihr Fehlen, wenn sich keine Defektstruktur der ge-nannten Art im Fokus der anregenden Strahlung befindet. Die Raman-Streuung im ungestörten Kristallinneren hat also nach 5. einen anderen Anregungsmechanismus als die hier beschriebene an Defektstrukturen. Eine solche Defektstruktur im Kristallinneren er-scheint bei ultramikroskopischer Beobachtung meist als nahezu kugelförmiger Kristallit. In 2 zeigen Abb. 1 und Abb. 2 einen besonders ausgedehnten Defekt, der auch zur Anregung von Raman-Spektren benutzt wurde. Ähnliche, als "negative Kristalle" bezeichnete Defekte gibt es z. B. auch in Cu20-Einkristallen 3 . Wie erst jetzt bekannt wird 4 , ist der zur Messung verwandte, farb-lose LiF-Einkristall Teilstück eines im Vakuum gezo-genen größeren, der zur Erzeugung von Farbzentren mit kurzwelliger Röntgen-Strahlung bestrahlt worden ist. Die Defekte sind nach dem Herstellungsverfahren der Kristalle wahrscheinlich Hohlräume. Wegen der Röntgen-Bestrahlung können sie auch F2 enthalten 5 . Ihre in den Kristall hineingewachsenen Oberflächen bleiben so vor äußeren Einwirkungen geschützt und sind daher als besonders gut zu bezeichnen. Damit ist gemeint, daß sich dort die Störung des idealen
Intramolekulare Excimere: Die Kinetik ihrer Bildung und Desaktivierung
Authors: Klöpffer Walter , Liptay Wolfgang 
Published: February 2015

A set of kinetic equations has been developed which allows to calculate the rate parameters of intramolecular excimer formation, dissociation and of radiative and non-radiative desactivation processes. Experimental data necessary for evaluating the equations are monomer lifetime and relative fluorescence intensities of monomer and excimer fluorescence in solution with and without added quenching substance.
Spectroscopical data of biscarbazolyl propane, diphenyl propane and derivatives are used in order to calculate the rate constants. It is shown that the stronger excimer fluorescence of diphenyl propane, as compared with biscarbazolyl propane, is due to the high rate constant of excimer formation in the former substance
Charakteristische Parameter der dielektrischen Relaxationszeit starrer Dipolmolekeln in verdünnter Lösung / Characteristic Parameters of the Dielectric Relaxation Time of Rigid Dipole Molecules in Diluted Solution
Authors: Hufnagel F. 
Published: February 2015

The dielectric relaxation time of rigid polar molecules in dilute solutions is shown to depend exponentially on an effective molecular radius which is independent of the solvent. This relation contains a temperature-dependent structure parameter, the coefficients of which are used to calculate the activation energy and -entropy of the rate process. The resulting entropies are now more satisfying due to a new formulation of the scattering factor.
Similarly the viscosity of the solvent and its structure parameters are related by an exponential law. A characteristical length in this relation is a measure of the "hole distance" of the rate process. From both exponential laws follows that the dielectric relaxation time raised to the power of the ratio of effective molecular radius to hole distance is proportional to the viscosity of the solvent
On the Thermomagnetic Gas Torque for Collinear Static and Alternating Magnetic Fields
Authors: Hess S. , Waldmann L. 
Published: February 2015

Abstract
Results obtained within the framework of kinetic theory are presented for the part of the thermo-magnetic gas torque which stems from the thermal pressure and is associated with the influence of the magnetic fields on the viscosity (Senftleben-Beenakker effect). Good qualitative agreement and a quantitative agreement within a factor of roughly 1.5 are found between the theory and the experimental data of Smith and Scott [1969].
Streuung schneller Elektronen in einem Gasplasma/Scattering of Fast Electrons by a Gas Plasma
Authors: Boersch H. , Geiger J. , Topschowsky M. 
Published: February 2015

Abstract
The elastic and inelastic scattering of 25-keV electrons by argon and by an argon discharge has been measured in the small angular region ϑ ≦ 2 x 10-2 rad. The angular resolution was 5 x 10-5 rad. The experimental result for scattering by neutral argon atoms is in agreement with theory. In the case of the argon plasma, where free charge carriers (ions and electrons) are present, the number of electrons scattered into the angular range ϑ ≦ 10-3 rad increases enormously. It is shown, that because of the large differential Rutherford cross section at small scattering angles multiple scattering occurs by the free charge carriers. The densities of ions and of electrons in the plasma can be obtained from the width of the multiple scattering distribution.
Experimentelle Untersuchung der Ausheilprozesse von Strahlenschäden, die durch 14 MeV-Neutronen bei 77 °K in Germanium entstehen/Investigation of the annealing processes in germanium irradiated at 77 °K with 14 MeV neutrons
Authors: Wolf Dieter 
Published: February 2015

Abstract
n- and p-type Germanium at 77 °K has been irradiated by 14 MeV-neutrons and subsequently annealed. The results are compared with those obtained from reactor irradiated materials.
The observed changes of Hall-constant and electrical resistivity of n- and p-type Ge can be de-scribed by the disordered regions model.
In p-Ge the disordered regions decay by isochronal annealing between 77 °K and 230 °K. This process is superposed by the process of the creating and the decay of a type of defect that has also been observed after electron irradation.
After reactor-neutrons irradiation n-Ge shows a reverse annealing between 100 °K and 150 °K. In this temperature interval no steady state annealing effects have been observed after 14 MeV-neutrons. It is suggested that during each annealing stage vacancies diffuse out of the defect zones and are trapped by small defect clusters in reactor irradiated n-Ge. In 14 MeV irradiated material nearly no such small clusters are present, so the vacancies diffuse until they are retrapped by the disordered regions. The process of back diffusion can be measured. It obeys an exponential law. Between 150 °K and 230 °K after either type of irradiation a reverse annealing takes place. It is suggested that in this annealing interval the defects of the disordered regions become divacancies.
Notizen: Die Rotation der γγ-Winkelkorrelation der Kaskaden (570 – 797) keV, (570 – 797 – 605) keV und (797 – 605) keV von Ba134 in einem äußeren Magnetfeld/ The Rotation of the γγ Angular Correlation of the Cascades (570–797) keV, (570–797–605) keV and (797–605) keV of Ba134 in an External Magnetic Field
Authors: Beer H. 
Published: February 2015

Abstract
The over all γγ angular correlation of the cascades (570-797) keV, (570-797-605) keV and (797-605) keV in Ba134 was perturbed by an external magnetic field of 41.4 kG perpendicular to the directions of observation of the quanta. The rotation of the angular correlation was found to be
ωτ=0.05±0.03 .
This result could be due to the 2+ 605 keV or te 4+ 1400 keV energy level or to both level with measurable portion. The aspects of these alternatives are discussed.
Zur Begrenzung der radialen Ausdehnung des Lichtbogenstromes durch ein axiales Magnetfeld
Authors: Klüber O. 
Published: February 2015

Abstract
In an arc without external magnetic field the current carrying region is identical with the conducting plasma column. This is no longer generally true if the arc is in an axial magnetic field and if the electrode radius is much smaller than the plasma radius. Radial current components then produce a rotational motion of the plasma and an azimuthal Hall current, and hence electromotive forces which try to suppress the current perpendicular to the magnetic field. In a plasma with finite viscosity the rotation is determined by the Navier-Stokes equation, which is solved here for a homogeneous plasma simultaneously with generalized Ohm's law. The results show that the plasma rotation is always an essential, and often the dominant, mechanism for guiding the arc current parallel to the magnetic field lines.
Studies on the PMR Spectra of Oxetanes
Authors: Jokisaari Jukka , Ruotsalainen Heikki 
Published: February 2015

Abstract
The oxetane parts of 2-(4-methylphenyl) oxetane, 2-(2,4-dimethylphenyl)oxetane and 2-(2,4,6-tri-methylphenyl) oxetane have been analysed as the ABCDE spin systems from the 60 MHz PMR spectra. The chemical shifts and the proton-proton couplings of the protons in the oxetane rings have been solved through iterative calculations. The possible phenomena which may affect the chemical shifts and couplings have been investigated. One of the most dominating factor seems to be the non-planarity of the oxetane ring. The ring current effects of the 2-substituents and the field effects of the methyl groups shift the resonances of the oxetane ring protons.
Supraleitung und Existenzbereich der A15-Phase im System Nb—Al—Ge
Authors: Müller A. 
Published: February 2015

Abstract
Es wird der isotherme Schnitt bei 1840 °C im System Nb-Al-Ge mit mehr als 60 At.-% Nb untersucht und der Existenzbereich der A 15-Phase abgegrenzt. Kritische Temperaturen, Gitterkonstanten und Härte werden abhängig von der Zusammensetzung der A 15-Phase dargestellt. Tc-Werte einphasiger Proben mit ≈ 75 At.-% Nb lassen sich sowohl nach Valenzelektronen als auch nach Quotienten aus errechneten und gemessenen Gitterkonstanten ordnen. Beide Korrelationen weisen darauf hin, daß die obere Grenze der kritischen Temperatur im ternären System auch für metastabile A 15-Phase nicht höher als 22 K liegt.
Messung kernmagnetischer Relaxationszeiten in Hochauflösung mittels schneller adiabatischer Passagen
Authors: Lütje Hans 
Published: February 2015

Abstract
The nuclear magnetic relaxation times T1 and T2 may be determined by observing the relaxation that follows after a stop of an adiabatic fast passage at different points of the resonance signal.
High resolution measurements are possible with external proton stabilization during the relaxation process if the chemical shifts are larger than 1 ppm and the relaxation times are longer than 1 sec. If no high resolution is required the lower limit is 0.2 seconds. Relaxation measurements are possible using conventional NMR-spectrometers without additional equipment. Since the signal to noise ratio is favourable, rather dilute solutions may be investigated. Relaxation measurements on benzene, on 4 different protons of 4-dimethylamino-benzaldehyde and on polyethylene oxide in solution are reported.
A Quantitative Study of the Nuclear-Electron Overhauser Effect of Phosphorus-31 in Solutions
Authors: Müller-Warmuth W. , Grützediek H. , Van Steenwinkel R. 
Published: February 2015

Abstract
The nuclear-electron Overhauser effect of 31 P and its spectral dependence has been studied in free radical solutions of two selected solvents containing phosphorus in the oxidation states three and five. Measurements of the dynamic polarization enhancement factor and of the relaxation times of 31 P and 1 H have been carried out on trimethylphosphite, (CH3O)3P, and triethylphosphate (C2H5O)3PO at three widely separated magnetic field values, and at various temperatures. Triple resonance experiments in the same solutions did not show any evidence of a “three spin effect”, in contrast to diethylphosphite (C2H5O)2P(H)O which was also investigated. From the polarization coupling parameter and the fluctuations of the dipolar interactions, the importance of scalar contact coupling, the spectral intensity functions and the (scalar) correlation times have been determined. The results have been discussed in terms of the pulse model of molecular collisions, where the average time dependence of the scalar coupling constant is calculated. The phosphorus-unpaired electron coupling is described by different coupling mechanisms of different ranges, depending upon the environment of phosphorus and the hybridization of the bonds. Among the mechanisms capable of affecting the dynamic nuclear polarizations of both triply and quadruply connected phosphorus, the interaction via the lone pair electrons which are present in the first case only, is the most likely to play a dominant rôle.
The Nuclear-Electron Overhauser Effect of Carbon-13 as Studied by Multi-Field Dynamic Polarization Experiments in Solutions
Authors: Grützediek H. , Müller-Warmuth W . , Van Steenwinkel R. 
Published: February 2015

Abstract
Experimental dynamic nuclear polarization (DNP) studies at 176 gauss, 3420 gauss, and 13 200 gauss and at various temperatures have been concerned with the Overhauser effect of solvent carbon-13 nuclei in solutions of free radicals. Detailed measurements have been made in solutions of benzene and methyl iodide. The relative importance of scalar and dipolar coupling, the correlation times and spectral intensity functions have been of the greatest interest. The importance of the “three-spin-effect” has been investigated by applying triple-resonance irradiation. Dipolar and scalar hyperfine couplings between carbon-13 nuclei and odd electrons are of comparable magnitude, where the main difference of the DNP enhancement factors is caused by different shapes of the spectral intensity function for the fluctuations of the scalar interaction. The results are discussed in terms of the molecular structure and of the collision attitudes.