bluuebunny/crossref_metadata_2025 huggingface dataset:
Systematische Untersuchungen der dynamischen Protonenpolarisation in organischen Kristallen mit eingebauten Radikalzentren
Authors: Grude K. , Müller-Warmuth W.
Published: February 2015

In order to produce high proton polarizations, several organic hydrocarbons have been doped with stable free radical molecules. Through the "solid state effect" a part of the electronic polarization in a magnetic field has been transferred to the protons of these materials. For this purpose, the "forbidden electronic transitions" of the combined electron-proton system have been saturated at about 37 GHz. The enhancement factor of the dynamic proton polarization was measured by pulsed NMR at 56 MHz. In phenanthrene with about 4 w.% bis-diphenylen-phenylallyl (BPA) a maximum polarization of 10.5% has been obtained at 1.5 °K and 13 200 gauss. This value may be increased by extending the temperature and magnetic field range. Systematic investigations in numerous organic systems have been carried out and have particularly yielded data on the frequency dependence and on the saturation behaviour of the enhancement curves. - Spin temperature theories of dynamic polarization have been considered to explain the results and to find possibilities for improving the polarization. In particular, the exchange interaction of the radicals and the distinction between relaxing and polarizing paramagnetic centres had to be taken into account.
Notizen: Fallout der chinesischen Kernwaffenexplosion vom 27.12.1968
Authors: Fahland J.
Published: February 2015

Short-lived radionuclides have been measured in fallout of the Chinese nuclear test of Dec. 27th, 1968. The measured yield ratios of the nuclides 95Zr,111Ag, 115Cd, 156Eu, 237U and 239Np have been corrected for fractionation effects and compared to calculated ratios. Free parameters of the calculation such as most frequent neutron energy, time integrated neutron flux, and fission material were adjusted by means of a least square criterion. The most frequent energy was found to be 5 keV. The corresponding Maxwellian time integrated flux was 3·1023 n/cm2 . In addition, a 14 MeV-time integrated flux of 1·1023 n/cm2 had to be assumed. The converted fission material was 235U and 238 U with 15% 235U.
Zur Quantentheorie des elektrischen Restwiderstandes II.
Authors: Rauh A
Published: February 2015

The influence of short-range order on the residual resistivity of Cu3Au is investigated within a formalism previously reported. As compared to analogous methods based on the Boltzmann equation, the scattering of electrons by three correlated impurity centers is included. The characteristic numbers needed to describe the short-range order between the three centers can be determined within narrow limits by probability theory, using measured values for the Cowly-parameters. The change of restistivity due to the short-range order is found to be reasonably dealt with by including the two-center correlation only. However, as is further shown, this correlation cannot be taken into account correctly by the Boltzmann equation. For the electrical conductivity of alloys an expression is proposed which is to replace the familiar semiclassical result obtained from the Boltzmann equation.
Elektrolumineszenz in ZnS:Cu-Einkristallen
Authors: Haupt H. , Nelkowski H.
Published: February 2015

Electroluminescence (EL) in ZnS :Cu-crystals often occurs in the shape of comets and double-comets, which are orientated perpendicular to the pseudohexagonal c-axis, mostly within the 〈10.0〉 directions. Crystals with strong stacking disorder (drawn from the melt) contain a great deal of luminescing lines. The EL of crystals with well built cubic structure (grown by iodine transport) however consists of few long double-comets (up to 2.3 mm). EL of crystals doped after growth and its comparison with photoluminescence, optical birefringence and the result of Cu-diffusion measurements confirm the assumption that EL occurs along Cu-decorated dislocation lines. It is shown that the local distribution of brightness essentially is not affected by a variable Cu-concentration along the dislocation lines but by the field distribution in the crystals.
Anodennahe Vorläufer elektromagnetisch angetriebener konvergenter Zylinderstoßwellen
Authors: Dammann H , Kleist G , Kogelschatz U , Bötticher W
Published: February 2015

The precursor in front of the convergent cylindrical shock-wave of Z-pinch discharges in Helium and Argon (diameter/length ratio: 44 cm per 10 cm) is investigated by interferometric methods. The precursors separate from the shock wave at higher filling pressures. It is found that the precursor exists only in a thin layer near to the anode. This effect can be explained by the assumption that the gas density in this region is lowered by a blast wave, which is formed in the early stages of the discharge by a still unknown process which depends on the sign of the discharge voltage.
The Diffusion of 3He and 4He in LiF
Authors: Kalbitzer S , Kiko J , Zähringer J
Published: February 2015

Helium isotopes were produced in single crystals of LiF by means of the nuclear reaction 6Li(n, 3H) 4He and by the subsequent decay of 3H into 3He. At a constant temperature of 620 °C the isotopic ratios of the outgassed helium isotopes were measured as a function of time respectively as a function of the released fraction. The ratio of the diffusion constants D3/D4 was found to be at most 1.02 which is considerably smaller than the maximum classical value of 1.155.
Electron Spin Resonance Spectra of Aliphatic Nitrile Radicals
Authors: Brumby Steven
Published: February 2015

Nitrile radicals have been generated in solution by photolysis of azo-compounds at 20 °C, and their electron spin resonance spectra have been studied. The radicals have the formula CH3C(CN)R where R=-CH3, -CH2CH3, -CH2CH2CH3 or -CH2CO2CH3.
Relations between Adiabatic and Incompressible (Non-Adiabatic) Systems and Their Stability
Authors: Krüger J. G. , Callebaut D. K.
Published: February 2015

We examine in general whether the results valid for an incompressible, non-adiabatic system can be deduced from the results valid for an adiabatic (or a more general) system. A simple rule will be established by which an energy principle for incompressible, non-adiabatic perturbations is obtained from the energy principle for adiabatic perturbations. Application yields in particular the energy principles for magnetodynamic, respectively gravitational, respectively gravitational and magnetodynamic stability for incompressible, non-adiabatic perturbations which are the analogues of the energy principles of Bernstein et al., respectively Chandrasekhar, respectively Krüger and Callebaut for adiabatic perturbations.

It is proved that an equilibrium state is more stable or at least equally stable for incompressible, non-adiabatic perturbations than for adiabatic ones. The conditions under which the adiabatic regime and the incompressible one are both stable or both unstable are studied.

More detailed comparison theorems are enunciated for the case of magnetodynamic stability and all cases where the energy integral for γ=0 is independent of ξ∥ the component of % parallel to B. If div ξ can be chosen arbitrarily when ξ⊥ is given then the adiabatic and the incompressible regimes are both stable or both unstable. A detailed examination whether div ξ can be chosen arbitrarily or not due to the presence of closed field lines leads to a classification of the perturbations in two cases. We compare the stability between these two cases for the adiabatic regime and for the incompressible one and for each case, the stability between both regimes. A similar analysis is given for restrictive conditions on div ξ due to the presence of closed pressure shells. In general only one case of the complete classification has to be considered to decide on the stability. More-over the adiabatic and incompressible regimes are both stable or both unstable for most infinitely long tubes. The whole treatment is illustrated by the example of the linear pinch.
Über ein Verfahren zur gleichzeitigen Bestimmung von Elektronenkonzentration und Elektronenstoßzahl in einem homogenen isotropen oder in einem langsam veränderlichen Plasma
Authors: Muschler W.
Published: February 2015

A method is described, which allows determination of the complex refractive index of a plasma by separate measurement of the E-and H-component of an electromagnetic wave. By means of the complex refractive index simultaneously electron concentration and electron collision frequency of the medium can be stated.

The measuring frequency depends upon absorption, precision requirements, and - for a locally varying medium - upon the availability range of theory used.

General considerations are applied to a plasma model (terrestrial ionosphere without magnetic field): Simultaneous measurement of electron concentration and electron collision frequency should be well possible within a height range corresponding to the terrestrial D-region. In higher regions determination of the (decreasing) electron collision frequency becomes more and more difficult, whereas possibilities for determination of the (increasing) electron concentration seem to improve.

The influence of reflected waves is considered in a following paper 4.
Zur Theorie des Zeeman-Effekts in Rotationsspektren
Authors: Sutter D. , Guarnieri A. , Dreizler H.
Published: February 2015

Starting with the Lagrangian function of a free molecule in an external magnetic field a more complete Hamiltonian, including nuclear susceptibilities, is derived. A Stark effect due to the translation of the molecule in the external magnetic field is predicted.
Die Wärmeleitfähigkeiten von reinem Para-und Ortho-Wasserstoffgas und ihren Gemischen bei 21 °K
Authors: Müller K. H. , Eichenauer W. , Heinzinger K. , Klemm A.
Published: February 2015

Measurements on gases at 21 °K in the whole concentration range from pure p-H2 to pure o-H2 result in the equation

λ/λp = 1-3.61·10-3γ-5.66·10-3y2.

λ and λ are the thermal conductivity coefficients of a mixture with the molar fraction γ of o-H2 and of pure p-H2 respectively. Existing theories assuming a spherical interaction potential can account for only about half the differences in thermal conductivities found experimentally.
Polaritons in LiJO3
Authors: Claus R.
Published: February 2015

Polaritons in LiJ03 associated with the phonons of sym-metry A at 328 and 795 cm"" 1 and symmetry Et at 769 cm -1 have been recorded using ordinary and extraordinary incident photons.
Kinetic Theory of Subsonic and Supersonic Transport Processes for Screened Coulomb Interactions
Authors: Wilhelm H. E.
Published: February 2015

A statistical theory of the intercomponent transport processes is given for nonisothermal plasmas consisting of electron and ion components, when the particles interact through Coulomb collisions screened electrostatically beyond the Debye-radius. The associated collision integrals are evaluated analytically for arbitrary drift velocities of the components, and under consideration of the velocity dependence of the Coulomb logarithm. The resultant analytical relations form consistent mathematical foundations for a transport theory of systems with collisional Coulomb interactions. It is shown that different properties of the transport processes and the effective Coulomb logarithms result for subsonic and supersonic drift velocities of the components
Tentatively Standardized Symmetry Coordinates for Vibrations of Polyatomic Molecules
Authors: Cyvin S. J. , Hägen G. , Cyvin B. N.
Published: February 2015

Twelve six-atomic models are treated as a part of the work on tentatively standardized symmetry coordinates of molecular vibrations
Bestimmung des komplexen Brechungsindex eines Plasmas mittels des Ausbreitungsverfahrens beim Auftreten reflektierter Wellen
Authors: Muschler W.
Published: February 2015

In a preceding paper a propagation method has been described that allows simultaneous determination of electron concentration and electron collision frequency in a slowly varying plasma - using its complex refractive index. A regular progressive damped wave had been assumed. In this paper the treatment is extended to the case that the original wave is superimposed by a reflected one. The calculations show that for distinct points in the direction of wave propagation the determination of both modulus and argument of the complex refractive index is again possible. The discrete sequence of measuring points does not restrict the local resolution of the method.
Ultrarot-Intensitäten von Acetylenen des Typs (CH3)3X - C ≡ C - Y
Authors: Hoffmann V. , Stehlik G. , Zeil W.
Published: February 2015

The absolute integrated infrared intensities of the C ≡ C- and the ≡ C - H-stretching vibrations of four acetylenes of the type (CH3)3X-C≡C-Y (X = C, Si and Y = H, D) are reported. The obtained values are discussed with respect to the eigenvectors of the normal coordinates of these vibrations and with respect to coupling between these two vibrations and also between these and other vibrations of the type A1 . An attempt is made to involve the experimental values in an assumed (p-d) π-interaction.
Two-Group Neutron Transport Theory with Anisotropic Scattering
Authors: Thielheim K. O. , Claussen K.
Published: February 2015

Two-group transport theory with anisotropic scattering in infinite homogeneous media is pre-sented in this paper. The kernel of the integral equation is expanded into a finite series of Legendre polynomials. Eigenfunctions and eigenvalues of the transformed integral equation are found and the number of discrete eigenvalues is calculated. The full-range completeness theorem as well as the orthogonality and normalization relations are presented. As an example the expansion coeffi-cients of the infinite-medium Green's function are explicitly calculated.
Photoablösung von Elektronen bei einigen stabilen negativen Ionen
Authors: Feldmann D.
Published: February 2015

Photodetaehment of electrons from some stable negative ions has been measured. Cross sections of about 10-17 cm2, and the following minimal detachment energies were found: H-: 0.776 eV, C-*: < 0.5 eV, CH-: 0.74 eV, C2
- : 3.54 eV, C2H- : 3.73 eV, SO-: 1.09 eV, and SO-: 1.0 eV with an accuracy better than + 0.05 eV.
and Cyclic Hydrocarbons on y-Aluminium Oxide
Authors: Sanesi Manlio , Wagner Vittoriano
Published: February 2015

The heats of adsorption on weakly activated γ-Al2O3 of a number of linear 1-monoolefins (C4 to C9) and cyclic saturated and unsaturated hydrocarbons have been measured by gas-solid chromatography and extrapolated to zero surface coverage.

The double bond contribution to the adsorption energy is shown by comparison of the adsorption heats with those of the corresponding saturated molecules and is related to the existence of Brensted acid centers on the adsorbent surface. The effect of cyclization is also shown.
Theoretical Investigation of a Temperature Instability in a Modified Penning Discharge (Q-PIG)
Authors: Klan F.
Published: February 2015

An instability connected with strong coherent oscillations of the electron temperature as observed in a PIG discharge is investigated theoretically. The energy equation of the electron gas involving the electronic heat flux as well as certain source terms is linearized. A simple dimensional analysis is used in order to avoid more complicated calculations. The stability criterion obtained in this way is evaluated to give a stability boundary in a certain parameter space. It is also found that the temperature perturbation should move with just the Ex B drift velocity of the electrons. The experimental observations agree surprisingly well with the theoretical predictions despite of the crude approximations involved.
Ein 1-Zoll-Rubin-Riesenimpulslaser mit 50 Hz Impulsfolgefrequenz
Authors: Mahlein H. F. , Schollmeier G.
Published: February 2015

Zum reproduzierbaren und störungsfreien Riesenimpulsdauerbetrieb mit 50 Hz Impulsfolgefre-quenz eines 1-Zoll-Rubinlasers, der in einem Rotationsellipsoid exfokal durch eine gepulste Queck-silberdampf-Höchstdrucklampe gepumpt wird, werden verschiedene Resonatorausführungen mit me-chanischer Güteschaltung untersucht. Es wird über die Elektronik für den mit 400 Hz rotierenden Güteschalter und die mit den verschiedenen Resonatorausführungen erzielten Ergebnisse berichtet. Die rasche Impulsfolgefrequenz und die in den Resonatoren auftretenden hohen Leistungsdichten im 50 Hz-Riesenimpuls-Dauerbetrieb verursachen eine schnelle Zerstörung der üblichen dielektrischen Spiegelschichten. Die besten Ergebnisse zeigt ein Resonator ohne dielektrische Spiegelschichten, der aus einem Rubin mit angeschliffenem totalreflektierendem Prisma und rotierendem 3-Platten-Reso-nanzflektor als Güteschalter besteht. Diese Anordnung ermöglicht reproduzierbaren Einzelimpuls-dauerbetrieb mit 50 Hz Impulsfolgefrequenz im durch die Prismendachkante gefalteten Grundmode, falls die Laserleistung pro Riesenimpuls von 20 bis 25 ns Halbwertsbreite 50 bis 60 kW nicht über-schreitet.
Binary Systems Formed by Alkali Bromides with Barium or Strontium Bromide
Authors: Riccardi Riccardo , Sinistri Cesare , Campari Giuseppina Yiganó , Magistris Aldo
Published: February 2015

By DTA and visual methods the phase diagrams of the ten binary systems formed by lithium, sodium, potassium, rubidium and cesium bromide with barium or strontium bromide have been drawn. Moreover, the fusion thermal effects regarding the eutectics and the congruent compounds singled out in the systems have been evaluated.

The general thermodynamic behaviour of these systems is discussed in comparison with the ideal one.
Über die Existenz der Schwingerschen Funktionale in der Quantenmechanik
Authors: Sohr H.
Published: February 2015

In der Feldtheorie bedient man sich in zunehmendem Maße des Funktionalkalküls. Beispiele dafür sind die S'-Matrix-Theorie und die Theorie der Schwingerschen Funktionale. Meist wird dieser Formalismus nur formal benutzt, ohne Konvergenzuntersuchungen. In dieser Arbeit soll die Konvergenz und damit die Existenz der Schwingerschen Funktionale als unendliche zeit-geordnete Operatorprodukte für eine Klasse von Systemen der Quantenmechanik bewiesen werden. Solche Systeme, z.B. der anharmonische Oszillator, werden in der Feldtheorie häufig für Modell-untersuchungen verwendet.
Untersuchungen über das Verhalten der chemischen Bindung im elektrischen Feld I. Das Fluorwasserstoffmolekül HF
Authors: Drossbach P. , Schmittinger P.
Published: February 2015

Das Fluorwasserstoffmolekül HF wurde unter Berücksichtigung seiner 10 Elektronen bei 5 verschiedenen Kernabständen und 10 verschiedenen elektrischen Feldstärken von 0,00025 bis 0,022 at. Einh. nach dem SCF-MO-LC(LCGO)-Verfahren berechnet. Das Dipolmoment wurde als Funktion des Kernabstandes und der Feldstärken berechnet. Bei positiven Feldstärken tritt eine Lockerung bis Zerfall der Bindung ein; bei negativen Feldstärken wird die Bindung fester.
Phasengleichgewichte und thermodynamische Analyse des Systems Antimon—Thallium
Authors: Predel Bruno , Schwermann Werner
Published: February 2015

Eine Revision der Gleichgewichtsverhältnisse im System Tl-Sb unter Verwendung thermo-analytischer, röntgenographischer und metallographischer Methoden ergab Gleichgewichtsverhältnisse, die von den bisher bekannten merklich abweichen. Es konnte unter anderem eine Verbindung der Zusammensetzung SbTl nachgewiesen und die Existenz von intermetallischen Phasen bei 10 und 25 At.-Proz. Sb erhärtet werden. Die Bestimmung der Schmelzenthalpie ermöglichte die Er-schließung der Mischungsenthalpien und Mischungsentropien der β-Thallium-Mischkristalle. Ferner gelang es, die Bildungsenthalpien der intermetallischen Phasen zu ermitteln. Es wurde gezeigt, daß die thermodynamischen Eigenschaften der β-Phase durch einen Umwandlungsanteil dominierend beeinflußt werden, der mit dem Übergang des Antimons von seiner stabilen Modifikation in eine kubisch raumzentrierte Struktur verbunden ist. Es konnte die Umwandlungsenthalpie und Umwandlungsentropie dieser hypothetischen Phasenumwandlung ermittelt werden.
Regelmäßige Relaxationsschwingungen in Rubinlasern durch Änderung des Resonators / Regular Relaxation-Oscillations of a Ruby Laser with with Varying Resonators
Authors: Malota F.
Published: February 2015

Regular Relaxation-Oscillations of a Ruby Laser with with Varying Resonators Regular relaxation-oscillations were observed in ruby lasers with moving resonator mirrors. The appearance of these oscillations depends on the mirrors speed and population-inversion, and is explained as synchronisation of different emitting regions, whereby each emitting region fulfills the conditions for the appearance of these oscillations as given by Röss.
Notizen: An Investigation of the 5.36 MeV Level in 6Li by Electron Scattering
Authors: Hutcheon R. M. , Neuhausen R. , Eigenbrod F.
Published: February 2015

The form factor for the excitation of the 5.36 MeV level in 6 Li has been measured in a momentum transfer region q = 0.3 ÷ 1.8 fm -1. Calculations of this form factor were performed with L - S coupled intermediate-coupling shell model wave functions.
Instabilität der positiven Säule endlicher Länge im magnetischen Feld / Instability of the Positive Column of Finite Length in a Magnetic Field
Authors: Janzen G. , Moser F. , Räuchle E.
Published: February 2015

The instability of a diffusion-dominated positive column of a gas discharge in a longitudinal magnetic field is investigated both experimentally and theoretically. Dispersion relations are derived for the case of an m = l helical instability considering the finite length of the column. Regions of instability are calculated for various wavelengths of the instability.

Experiments were carried out in a positive column of variable length, ranging from 8.5 to 40 cm. at varying pressures of about 0.1 Torr of Neon. There is a satisfactory agreement between theory and experiments. The main results are:

a) in long tubes instability occurs at a distinct magnetic field, calculated first by Kadomtsev and Nedospasov. Stable intermediate regions are possible at higher fields depending on the relations between the plasma-parameters;

b) in short tubes the column is stable again for higher magnetic fields; c) in very short tubes there is no instability of this kind. The observed frequency spectrum agrees with the theoretical values
Experimental Evidence of Clusters in Molten Alloys of the Eutectic Aluminum-Tin System by Means of a X-Ray-high Temperature-small Angle Scattering Apparatus
Authors: Hezel R. , Steeb S.
Published: February 2015

An apparatus for measuring X-Ray small- and wide angle scattering of solid materials and especially of molten metals with temperatures up to 1100 °C is described. Alloys of the eutectic system Al -Sn with tin-contents up to 30 At.-% are investigated. The influence of surface oxide layers on the scattered intensity is discussed. Correlation functions as well as the Guinier approximation yielded inhomogeneities with mean diameters up to 10 Å in the investigated melts. Therefore the dimensions of these so-called short range segregation zones correspond to those of the first coordination sphere
Raman-Spektren eines AsJ3-Einkristalls und von SbJ3-und BiJ3-Kristallpulvern / Raman spectra of an AsJ3-single crystal and of SbJ3- and BiJ3--crystal powders
Authors: Kiefer W.
Published: February 2015

Raman spectra of an AsJ3-single crystal were recorded using a quasicontinuous ruby laser, a double monochromator and a special registration electronics. The polarization measurements allow the assignments of the internal, translational and rotational modes of AsJ3 (factor group S6). Since SbJ3 and BiJ3 have the same space group and the same number of molecules per unit cell, one can assign the wavenumbers of the crystal powder Raman spectra in analogy to AsJ3. The depolarization ratios of the Raman lines of AsJ3 in solutions were also determined
Fallout der chinesischen Kernwaffenexplosion vom 29. September 1969
Authors: Weinreich R. , Krebs E. , Wachner K.
Published: February 2015

The analysis of fallout from the Chinese nuclear test of September 29th, 1969, showed the typical features of a hydrogen bomb explosion. The fissionable material was probably 239Pu combined with 238U. However, the use of a combination of 235U and 238U employed in all earlier Chinese experiments cannot be excluded
Untersuchung alter Luftproben aus Salzen des deutschen Zechsteins
Authors: Freyer H. D. , Wagener K.
Published: February 2015

Samples of sylvinite, halite and kieserite of the German Zechstein formation have been analyzed for the content of atmospheric components. The gas contents are of the order of 10-3 cm3 NTP/g salt. N2, O2, Ar, CO2, CH4, H2 and sometimes H2S have been analyzed. Obviously, all gases are molecularly dispersed in the crystal lattice and, probably, have been in equilibrium with the corresponding components solved in the solution. On this basis it seems to be possible to obtain quantitative data on the atmospheric composition at the time of the salt formation.
The Propagation of Periodic Waves in a Two-level System
Authors: Hofelich F.
Published: February 2015

In this article the possibility for the propagation of periodic waves in a two-level system is discussed. It turns out, that in the absence of processes leading to loss and gain of energy, respectively, periodic waves only are possible. Their frequencies are always greater than the transition frequency of the two-level system. The frequency difference and the deviation of the wave profile from a sinusoidal form increases with the strength of interaction of light field and two-level systems.

After the introduction of loss and source terms it turns out that only isolated periodic waves exist. The asymptotically stable ones among them act as asymptotic solutions to all other wave solutions. The frequencies and wave forms are affected in a similar way as without loss and source terms.
Permittivity and Dielectric Relaxations in Liquid-Ammonia Solutions
Authors: Breitschwerdt K. G. , Schmidt W.
Published: February 2015

Dielectric constant and loss in liquid-ammonia solutions of alkali halides have been measured in the frequency range 0.7 - 70 GHz. At least one relaxation process exists in this frequency range in addition to the relaxation of the solvent molecules. The additional relaxation is ascribed to the orientational polarisation of ion pairs. The concentration of the ion pairs, calculated with a special model, is 30 - 50% of the total concentration. The interaction between ions and solvent molecules is discussed.
Notizen: Stabilisation der Emission eines Riesenimpuls- lasers gegen Kurzzeitschwankungen durch eine nichtlineare Resonatordämpfung
Authors: Zeidler G.
Published: February 2015

Die bei Riesenimpulslasern auftretenden Kurzzeitschwankungen im Subnanosekundenbereich werden mit Hilfe einer in den Resonator eingebrachten Farbstoffzelle mit Zwei-Photonenabsorption herausgedämpft, so daß ein glatter Zeitverlauf der Emission entsteht.
Einfluß eines homogenen Magnetfeldes auf die Polarisation von Fluoreszenzlinien des Cu I-Spektrums nach Elektron enstoßanregung/ Influence of a homogeneous magnetic field on the polarization of fluorescence lines of the Cu I-spectrum induced by electron bombardment
Authors: Anger G. , Hartrott M.V. , Martyn H.-U. , Oppen G.v.
Published: February 2015

Using atomic beam techniques the polarization of fluorescence lines of the Cu I-spectrum was measured in dependence on magnetic field strength. The Cu-atoms were excited by electron bombardment and the magnetic field was parallel to the electron beam. Due to the decoupling of the hyperfinestructure of excited levels of the Cu I-spectrum the polarization of some observed spectral lines [3247 Å (4p 2P3/2 -4s 2S1/2); 5153 Å (4d 2D3/2 -4p 2P1/2); 5218 Å (4d2D5/2 - 4p 2P3/2)] increases with increasing magnetic field strength. These polarization measurements, which correspond to investigations on resonance scattering of light done by HEYDENBURG et al., can be used for a determination of hfs-coupling constants of excited states. The measurements on the 3247 Å-resonance line are used for a comparison with results of accurate level-crossing-experiments. Satisfactory agreement is obtained. The discussion of the polarization of the 5153 Å-line yields an A-factor of (9.6 ± 1-0) MHz and a lifetime of τ ≈1.7 · 10 -8 sec for the 4d2D3/2-level.
Messungen der radialen Verteilungen von elektrischer Stromdichte und Temperatur im Wasserstofflichtbogen mit axialem Magnetfeld
Authors: Schwenn R.
Published: February 2015

The radial distribution of the axial electric current density in a stationary hydrogen arc with axial magnetic field was measured. This was done by shooting small induction coil probes across the arc. The experiments confirmed that the arc current is almost completely restricted to the magnetic flux tube defined by the cathode radius, as discussed in a previous paper. In the case of a hollow anode a distinctly tube-like current density distribution was found.

With the aid of the axial electric field measurements already presented temperature profiles in good agreement with other experimental methods were derived. In addition, the ohmic heat input into the arc could be determined. This is much larger than the energy that can be lost radially as a result of thermal conduction according to the measured temperature profile and the thermal conductivity known from the theory. The cause may be the Rayleigh-Taylor instabilities which were observed or radial mass flows directed outwards. Allowing for even relatively slow flows (υr ˂ 104 cm/sec) in the calculations one obtains good agreement with the measured distributions.
Notizen: Vibrational Excess Entropy of Equimolar KCl—KBr Solid Solution
Authors: Ahtee M. , Pesonen A. , Salmo P. , Inkinen O.
Published: February 2015

The Debye-Waller factors of the ions in equimolar KCl — KBr solid solution at 300 K have been determined from X-ray diffraction data. It was observed that the amplitudes of ther-mal vibration are slightly higher in the solid solution than in the pure components. The corresponding vibrational excess entropy was found to be about 10% of the entropy of ideal mixing.
Notizen: Impurity Diffusion in Isotopic 6Li and 7Li Metal
Authors: Ott A. , Lodding A.
Published: February 2015

The mobilities of foreign metal tracers in isotopically pure lithium matrices have been studied. Differential diffusivities have been obtained for Na, Ag, Au, Zn and Ga in Li. The behaviour of impurities whose diffusion is not of a regular vacancy character (Au, Ag, Zn) appears connected with the quantum effects in Li self-diffusion.
On the Heating of a Pinch
Authors: Mewe R.
Published: February 2015

The compression temperature of a theta pinch is calculated as a function of the circuit para-meters and the final /?-value of the plasma. One of the results is that the temperature, T, at the peak magnetic field, B, scales of (B B) t/s , where B is the initial rate of rise of the magnetic field. A possibility of combining two capacitor banks to increase the implosion heating rate is discussed.
Herstellung und Eigenschaften eines neuen (ZnCd)S: Mn-Präzipitat-LeuchtstofTes
Authors: Preslawski N.
Published: February 2015

Optimal conditions for the preparation of precipitate phosphors were determined by measurements of the spectral emission distribution under UV excitation (365 nm). The emission of the Mn peak goes with increasing Cd concentration through a maximum, independent of the method the Cd was incorporated. The increasing gain, stimulated by the addition of Cd, is discussed using known energy models.
Untersuchungen über das Verhalten der chemischen Bindung im elektrischen Feld. IV
Authors: Drossbach P. , Schmittinger P.
Published: February 2015

Es wurden nach dem SCF-LC(LCGO)-Verfahren die folgenden Moleküle geredinet: H2 ohne und mit elektrischem Feld, HCl, HCIO, LiF ohne und mit Feld, LiCl, NaF und NaCl. Die Dichte-verteilungsfunktionen der Orbitale des LiF und die Orbitalschwerpunkte aller Moleküle wurden aufgezeichnet.
Zur Strömung kompressibler Plasmen im Eigenfeld von Lichtbogenentladungen
Authors: Hügel Helmut
Published: February 2015

The flow of compressible plasmas in axisymmetric channels of constant or variable cross sections under the influence of electromagnetic bodyforces and of Joule heating is described in terms of magneto-gasdynamics. The existing electric and magnetic fields are not independently applied, but originate as the electric field and self-induced magnetic field from a d. c. arc-discharge.

Under the condition of low magnetic Reynolds numbers a quasi-one dimensional description of the flow is given using the flow parameters velocity, Mach number, pressure, density and temperature. For these quantities five coupled first-order differential equations are obtained. A qualitative discussion outlines typical solutions and points out some features which are the same for flows in arc-discharges and for flows in so-called crossed fields. The conditions for a continuous passage through the sonic point are discussed. For flows in diverging nozzles results of numerical integration are presented.

Experimental investigations are reported which verify the self-magnetic effect in nozzle flows. At arc currents of 500 to 3000 amps measured values of thrust and Mach number show satisfactory agreement with theoretical results.
Nuclear Structure of 6Li and High-Energy Electron Scattering
Authors: Lodhi M .A . K .
Published: February 2015

The nuclear charge form factgr from the high-energy elastic electron scattering on 6Li has been calculated from the modified independent-particle shell model (IPSM) wave function. The usual harmonic oscillator type IPSM wave function has been modified by the inclusion of a nucleon-nucleon correlation function which involves extra-core nucleons only. The technique is extremely simple and provides an excellent agreement with the experimental data.
Relative Line Intensities in the Lyman Bands of HD and H2
Authors: Becker K. H. , Fink E. H.
Published: February 2015

Relative intensities of P (J'+ 1) and R (J '-1) lines have been measured in the (ν′ = 3, ν") progressions of the Lyman bands of HD and H2 . The intensity ratios are in good agreement with previous experimental data and with the results of theoretical calculations which account for the centrifugal dis­tortion.
Ein Mikrowellen-Mikrowellen-Doppelresonanz- experiment. Abtrennung der höherfrequenten Pumpe vom Detektor durch Verwendung gekreuzter Felder
Authors: Andresen U , Rudolph H. D.
Published: February 2015

In a microwave double-resonance experiment involving three rotational levels of propylene oxide perpendicular polarization of the pump and signal radiation was employed to prevent the higher-frequency pump radiation (24 GHz) from reaching the signal detector (11 GHz). For this purpose the independent cut-off characteristics of the TE10 and TE01 waveguide mode were exploited which depend only on the broad or small-face waveguide dimension, respectively.
Atomic-K-X-Ray Intensity Ratios
Authors: Schult O.W.B.
Published: February 2015

Experimental K-X-ray intensity ratios Kα2/Kα1, Kα3/Kα , Kβ1/Kα1 , Kβ2/Kβ1 , Kβ3/Kβ1 , Kβ4/Kβ1 and Kβ5/Kβ1 have been determined for several elements with 63≤Z≤92. These ratios agree very well with the results of a fully relativistic calculation of transition probabilities by Rosner and Bhalla. The theoretical values are tested with an accuracy of better than one per cent for the ratios Kα2/Kα1 , Kβ2/Kβ1 and Kβ3/Kβ1 .
Elektronenbestrahlungsexperimente an Tantal
Authors: Meissner D. , Schilling W.
Published: February 2015

In high purity Ta-foils the damage production during electron irradiation at 4.5 °K has been studied using electrical resistivity measurements. The observed dose curves show a strong saturation effect, i. e., the effective damage rates decrease with increasing defect densities. Two mechanisms contribute to this radiation annealing effect: 1) Spontaneous recombination of newly produced interstitials or vacancies with vacancies or interstitials already present in the crystal (direct re­ combinations) and 2) spontaneous recombination of close Frenkel pairs under the influence of nearby low energy recoil events (subthreshold events). The contribution of both direct recombin­ations and subthreshold events can be separated by subthreshold test irradiations as well as by radiation doping experiments. Both methods yield mutually consistent results. From these one can deduce a value of the spontaneous recombination volume of about 50 atomic volumes and a value for the cross section for the spontaneous recombination of a close Frenkel pair by subthreshold energy transfers from 1.2 MeV electrons of about 90,000 barns.
Rotationsstruktur im 21,22 eV-Photoelektronenspektrum von H2
Authors: Brehmund Burkhard , Frey Rüdiger
Published: February 2015

Rotational Structure in the 21.22 eV Photoelectron-Spectrum of H2: The form of the vibrational steps in the 21.22 eV potoelectron-Spectrum of H2 was analysed using a retarding field electron energy spectrometer with 10 meV resolution and a computer programme for a least squares fit analysis. Even though the broadening caused by the thermal motion of the H2 molecules during the photoionization process prevented the complete resolution of the rotational structure, it is possible to conclude from the results that the angular momentum of the nuclear rotation does not change in the photoionization process of H2 molecules with 21.22 eV photons.
Curie-Weiß Temperature Dependence Of Paraelasticity
Authors: Tretkowski J. , Völkl J. , Alefeld G.
Published: February 2015

Anelastic strains exceeding elastic strains up to a factor of 30 have been observed close to the critical point of H in Nb. The temperature dependence of the relaxation strength follows a Curie-Weiß law for temperatures (T - Tc)/Tc ≥ 6-10-3.
Feldtheoretische Konstruktion der Jordan—Brans—Dicke-Theorie / Fieldtheoretic Construction of the Jordan-Brans-Dicke-Theory
Authors: Grünberg H. von
Published: February 2015

In the framework of Lorentz invariant theories of gravitation the fieldtheoretic approach of the generally covariant Jordan-Brans-Dicke-theory is investigated.

It is shown that a slight restriction of the gauge group of Einstein's linear tensor theory leads to the linearized Jordan-Brans-Dicke-theory. The problem of the inconsistency of the field equations and the equations of motion is solved by introducing the Landau-Lifschitz energy momentum tensor of the gravitational field as an additional source term into the field equations. The second order of the theory together with the corresponding gauge group are calculated explicitly. By means of the structure of the gauge group of the tensor field it is possible to identify the successive orders of the scalar-tensor theory as an expansion of the Jordan-Brans-Dicke-theory in flat space-time. The question of the uniqueness of the procedure is answered by showing that the structure of the gauge group of the tensor field is predetermined by the linear equations of motion. The mathematical proof of this fact confirms formally the meaning of the equations of motion for the geometry of space.
On the Stability of Superheavy Nuclei against Fission, Alpha Decay and Electron Capture
Authors: Grumann Jens , Morovic Tihomir , Greiner Walter
Published: February 2015

The potential energy surface has been calculated by two methods which are compared with re­spect to spontaneous fission. In the first one essentially the sum of the single particle energies is computed as was done in a previous paper3 while in the second one the Strutinsky technique of renormalizing to a liquid drop model has been applied. Also the half-lives for electron capture are investigated together with the predictions of the half-lives for spontaneous fission and α-decay. The results support the existence of superheavy nuclei in the regions around Z = 114 and Z = 164.
Spectral Investigations of Some Rare Earth β-Diketonates in the Region 750—250 cm-1
Authors: Mehta P. C. , Tandon S. P.
Published: February 2015

The infrared absorption spectra of fifteen La3+, Pr3+, Nd3+, and Sm3+ β-diketonates have been studied in the spectral region 750-250 cm-1. The existence of three metal-oxygen vibration modes suggests D3 symmetry for the chelates under study. The stretching force constants, fMO , of the MO bonds have been computed from the observed infrared M-O vibrations using the method of Müller. The value of fMO is nearly constant (~ 2.7x105 dynes/cm) in all the chelates suggesting similar bond strengths.
Notizen:Zinndioxidschichten auf stabilisiertem Zirkon­dioxid als Kathoden in Hochtemperatur- Brennstoffzellen
Authors: Böhm R. , Kleinschmager H.
Published: February 2015

Durch "Chemical Vapour Deposition" auf porös auf­gerauhtem Träger aus stabilisiertem ZrO2 abgeschiedene SnO2-Schichten mit mehr als 8 At.-Proz. Sb können als Ka­thoden in Hochtemperatur-Brennstoffzellen bei 1000 °C ver­wendet werden; die Materialkombination übersteht Tempera­turzyklen zwischen Betriebs-und Zimmertemperatur ohne Be­einträchtigung der Haftfestigkeit oder der elektrischen Funk­tion.
Untersuchung der Eigenschaften von Haftstellen in ZnS-Kristallen durch Leitungs-und Thermolumineszenzmessung
Authors: Thoma Peter
Published: February 2015

Measurements of the thermoluminescence between 4,2 and 200 K and of the conduction properties of different ZnS-single crystals with thicknesses between 1 mm and 2 μm are performed. It is shown that the trap centers, which cause the optical glow curves, are quite different from those centers, which act as traps for carriers being injected from outside in the course of conduction experiments.
The Strength of Piezoelectricity in Liquid Crystals
Authors: Helfreich W.
Published: February 2015

A simple method combining macroscopic and microscopic features is proposed to calculate approximate values for Meyer's piezoelectric coefficients. The numerical result suggests that the piezoelectricity of liquid crystals is weak and its effect on alignment fluctuations mostly negligible.
Notizen: Reversed Isotope Dependence for Hydrogen Diffusion in Palladium
Authors: Völkl J. , Wollenweber G. , Klatt K.-H. , Alefeld G.
Published: February 2015

Gorsky-effect measurements applied to H and D in Pd show that D diffuses faster than H in the temperature range from about -60 °C to 200 °C. The diagonal components of the dipolemoment tensor has been estimated as 3.5 eV.
The Slip Problems for a Simple Gas
Authors: Loyalka S.K.
Published: February 2015

Simple and accurate expressions for the velocity slip coefficient, the slip in the thermal creep, and the temperature jump coefficient are obtained by applying a variational technique to the linearized Boltzmann equation for a simple gas. Completely general forms of the boundary conditions are used, and the final results are presented in a form such that the results for any particular intermolecular force law or the gas-surface interaction law can easily be calculated. Further, it is shown that, with little extra effort, the present results can be easily extended to include the case of a polyatomic gas. It is felt that the present work, together with a recent paper in which the author has considered the solutions of the linearized Boltzmann equation for a monatomic multicomponent gas mixture, provide the desired basis for the consideration of the various slip problems associated with the polyatomic gas mixtures.
Nonisothermal Diffusion Measurements on Granular Solids: Noble Gas Diffusion in Fused Silica
Authors: Abe M. , Rauch B. , Brandt W. W.
Published: February 2015

Samples of fused SiO2 and of a soda-lime glass were exposed to He, Ne, and Ar at temperatures between 523 and 763 °K, cooled to room temperature, transferred to a desorption cell, and then heated slowly and uniformly. The cell was connected to a mass spectrometer and the desorption rates were measured as a function of time. From the data, the parameters E and Do of the Arrhenius equation for the diffusion coefficient [D = D0exp(-E/RT)] were calculated. The results were found to agree rather well with literature data obtained on similar glasses using isothermal methods. Since the nonisothermal technique may be very useful for the study of granular materials and powders, the problems related to the presence of a grain size distribution and to the irregularities of grain shapes are treated in this study in some detail.
Viscosity of Ammonia and its Mixtures with Noble Gases in an Electric Field
Authors: Tommasini F. , Levi A.C. , Scoles G.
Published: February 2015

The component η3 of the viscosity of ammonia increases in an electric field. The effect depends on E2/ p and tends to a saturation value close to that found from measurements in a magnetic field. In ammonia-helium mixtures the saturation value of the effect decreases and becomes negative at an ammonia concentration of about 40%.
Untersuchungen zur Streulichtverteilung an Gläsern mit Phasentrennung / Angular Dependence Light Scattering Studies of Glasses Showing Phase Separation
Authors: Becherer G. , Göcke W . , Herms G.
Published: February 2015

By investigating the angular distribution of light scattered by glasses showing diffusion con-trolled phase separations, data can be obtained about the dimensions of the scattering particles without knowing absolute scattering intensities or further physical and chemical properties of the glass. - A known model of the scattering particle, based on diffusion controlled growth, may satisfactorily describe the conditions within the scattering sample, as shown by Gaussian least square calculations. The model and its scattering curves may explain the experimentally observed maximum of intensity at large scattering angles. Interpretation of scattering curves shows the influence of the diffusion zone on the intensity curve and supplies not only the radius of the inner "nucleus" of the scattering particle, but also the dimensions of the diffusion zone. - According to diffusion controlled growth, the volumes, and not the radii, of the growing particles turned out to be proportional to heat treatment time.
Zweistufige metastabile Zerfallsprozesse in Feldionisations-Massenspektren
Authors: Beckey H. D.
Published: February 2015

The kinetics of metastable decomposition of primary fragment ions of organic molecules is studied by a field ionization mass spectrometer. It is shown that a water molecule is eliminated f r om 1-hexanol within a very short time interval after field ionization (10-12<t<10-8 sec).The(M-H2O)+ ion eliminates CH3 , CH4 or C2H4 , respectively, in a second step after about 2x10-6 sec. The equations for calculation of the apparent mass of a metastable secondary fragment ion formed by a fast primary fragment ion are given.