bluuebunny/crossref_metadata_2025 huggingface dataset:
Elektrophotolumineszenz an ZnS: AI, Zn-Kristallen
Authors: Schmid Günter , Matossi Frank
Published: March 2015

Electrophotoluminescence (GUDDEN—PoHL-Effect) was observed with ZnS: Al, Zn single crystals. The effect is restricted to a narrow range near the anode, in agreement with previous assumptions. The dependence of the effect on bias voltage, temperature, duration of dark interval and excitation is investigated and discussed.
On the Relations between ESR-Hyperfine Splittings and Spin Densities in Simple Substituted Alkyl Radicals
Authors: Fischer Hanns
Published: March 2015

A simple treatment of spin densities and ESR-coupling constants of substituted alkylradicals

is developed. It is shown that the spin densities ρa in the α-carbon 2 pz-functions may be calculated by use of a product rule from substituent parameters 1 (Xi). Furtheron it is found, that the parameters Q in the well known relations a = Q-ρa are unique constants for rotating methylgroups, whereas for α-protons they depend on the electron withdrawing forces of the substituents.

Values of Δ (Xi) and QHH
CH are tabulated and discussed. The ESR-coupling constants of four new transient alkyl radicals are also given.
Plasmadiagnostik durch nichtlineare Resonanzwinkelstreuung
Authors: Salat A. , Schlüter A.
Published: March 2015

Nonlinear scattered light with twice the frequency of the incident beam is in phase with the mechanism by which it is produced for some particular angle of emission, and hence has a resonant character in that direction. The angle is a function of the electron density in the plasma. The intensity and the angular width of the resonant beam are discussed. The experimental application to present laboratory plasmas may be practicable, when strong lasers are developed in the infrared region.
Druckerhöhung in der zylindersymmetrischen Lichtbogensäule bei überlagertem axialem Magnetfeld
Authors: Witkowski S.
Published: March 2015

Numerical calculations of pressure increase in the plasma of a cylindrical arc column are presented. We assume applicability of the corona-equation. Results are given for magnetic fields up to 50 kΓ, external pressures of 10 –1 to 2·105 dyn/cm2 and temperatures up to 80 000°K. Finally, the results are compared with calculations using the SAHA-equation.
Zur Bestimmung von Temperatur und Geschwindigkeit der Plasmaströmung aus einem Plasmabrenner
Authors: Ahlborn B.
Published: March 2015

A two-step model of the heating processes in a plasma jet is given. In this model, a hot interior and colder sheath is postulated, and the conservation theorems for mass, momentum and energy are solved so that the plasma velocity and temperature can be calculated if the power supply, pressure fall over the heating length, and the cross-sectional area of the luminous plasma stream are known. The accelerating action of the electromagnetic forces is considered as well as the J o u l e heating caused by the arc current.

This model was tested by using a newly developed method to measure the average velocity and by using spectroscopy to measure the temperature of the plasma jet. The applicability of the “two step” model is shown by these experiments.
Notizen: Nachweis der bei der Spaltung von Alkalihalogeniden in Luft adsorbierten Wasserschichten mit dem „Omegatron“
Authors: Adam R. W. , Harsdorff M.
Published: March 2015

In der vorliegenden Arbeit wird die lagenweise Desorption von Wasseradsorptionsschichten von in Luft gespaltenen A lkalihalogeniden bei der Erhitzung im Hochvakuum untersucht.
Some Remarks on Gravitational Interaction and Gravitational Waves
Authors: Braunss G.
Published: March 2015

A brief consideration of the problem of gravitational waves is given on the basis of the following assumption: The components of the metric tensor are functionals of a field by which, in the sense of HEISENBERG’S nonlinear theory, all other fields resp. the corresponding interactions can be deduced. For the sake of mathematical simplicity a scalar field Φ (noncharged bosons) is considered instead of a spinor field. The condition gmn=gmn (Φ) resp. Rmn = Rmn (Φ) leads to the statement that the concept of a free gravitational wave, i. e. a wave which is a solution of Rmn=0 or Rklmn = 0, cannot be accepted. A free wave is here by definition a wave which is so far from the origin that one can neglect in the field eqs. all terms which represent a strong interaction. A comparison with a spinor field leads, with regard to this definition, to the conclusion that a free wave may be considered as a neutrino wave and gravitation as the weakest interaction possible of neutrino fields.
Durch Spallationsreaktionen und Neutroneneinfang erzeugtes 36Cl in Meteoriten und die prae-atmosphärische Größe von Steinmeteoriten
Authors: Begemann F. , Vilcsek E.
Published: March 2015

The 36Cl produced by spallation reactions and neutron capture on 35Cl has been measured separately in three stone meteorites and one iron meteorite.

The spallation produced 36Cl activities - given in dpm per kg (Fe+Ni + 10 x Ca) -have been found to be (20.5 ±2) for Abee - Centre, (21.8 ±2) for Abee - Surface, (21.3 -26.2) for Leedey, and ≦ (22 ±10) for Norton County- Surface. They are in good agreement with those found in iron meteorites of comparable size and known terrestrial age.

The neutron induced activities in the same samples are (0.21 ±0.2), (0.08 ± 0.17), (1.7 ±1), and ≦ (30 ± 15) dpm/100 mg Cl. In spite of the large uncertainties highly significant conclusions can be drawn from these data regarding the mass loss of the meteorites during approximately the last million years, either by space erosion or due to ablation during the passage through the terrestrial atmosphere. Based on calculations of EBERHARDT, GEISS, and LUTZ the ratio of post-atmospheric to pre-atmospheric radius derived for the three meteorites is Abee: rM/R=0.86 or rΜ/R > 0.7 on the 3 σ significance level, Leedey (meteorite shower): rM/R=0.5, and Norton County: rM/R=0.77 or rM/R > 0.63 (3 σ level).

No neutron induced activity could be detected in the iron meteorite Cranbourne (Nr. 4). The total and spallation produced 36Cl of two adjacent samples - although differing in their Cl content by more than a factor of twenty-was the same within the experimental limits of error (4.7 ± 0.2) dpm/kg. The low value is attributed to a high terrestrial age and/or the size of this meteorite. 39Ar could not be detected (< 0.64 dpm/kg. 3 σ level).
Atomic Distribution in Molten Silver-Tin Alloy
Authors: Joshi M. L. , Wagner C. N. J.
Published: March 2015

Molten silver-tin alloys have been studied by x-ray diffraction technique, using a focusing Θ--Θ diffractometer with Mo-Ka radiation (quartz crystal monochromator in the diffracted beam). The scattered intensities Icoh
eu in electron units and the interference function I (K)=Icoh
eu/ƒ2 being the scattering factor) have been measured in the range of K=4 π sin Θ/λ = 1.4 Å-1 to K = 15 Å~-1 for 6 different alloy compositions at temperatures 100 °C above the liquidus line. Four alloys (from 62% to 82% Ag) were measured at 825 ℃.

The positions of the first maximum of Ieu or I(K) shift considerably with increasing silver content from K=2.25 Å-1 for pure Sn to K=2.64 Å-1 for pure Ag. The radial distribution function 4 π r2ϱ (r) and the probability function W (r) = ϱ (r)/ϱ0, where ϱ (r) and ϱ0 are the atomic and average atomic densities respectively, were obtained by FOURIER transform of I(K). The positions of the first maximum of 4 π r2ϱ (r), (i. e., r1) and of W(r), (i.e., r1
1) are a measure of the interatomic distances, and vary from r1
1 = 3.18 Å for Sn to r1
1= 2.86 Å for Ag. The plot of r1
1 vs. composition of the alloys shows a negative deviation from a linear law. A discontinuity appears in the curve in the range of 50-60% Ag. The coordination number Z increases rapidly on addition of Ag to Sn (Z = 8.5 for Sn) and reaches a value of about 11 beyond 60% Ag.
Untersuchungen am inversen Pinch
Authors: Grönig H.
Published: March 2015

Es wird experimentell gezeigt, daß sich der inverse Pinch wegen seiner Symmetrieeigenschaften sehr gut dazu eignet, zylindrische Stoßwellen zu erzeugen, deren Leuchtfronten wohldefiniert und reproduzierbar sind. Zur Messung der Leuchtfront dienen eine KERR-Zellenkamera und ein Lichtleitersystem, während zur Untersuchung der Stoßfront selbst eine piezoelektrische Drucksonde verwendet wird. Die experimentellen Ergebnisse zeigen, daß Leuchtfront und Stoßwelle übereinstimmen und daß die Ausbreitung der Stoßwelle gut mit Hilfe des Schneepflugmodells beschrieben werden kann.
Zur Mechanik zweier Punktladungen bei Berücksichtigung der Retardierung
Authors: Schmutzer Ernst
Published: March 2015

The mechanics of two charged mass points is developed by taking into account retardation effects. Especially the formula for the force between the two charges is deduced. The result known from literature is not received.
Messungen der Argon-Diffusion in KCl und KBr
Authors: Richter A. H. K. , Zimen K. E.
Published: March 2015

Die Diffusion von radioaktivem Argon wurde in reinen und dotierten Einkristallen von KCl und KBr sowie in gepreßten Tabletten von KCl im Temperaturbereich von 300 — 700°C gemessen. Als Aktivierungsenergien wurden gefunden:

unterhalb 400°C 2,4 eV (55 kcal/mol) für KCl und 1,5 eV (36 kcal/mol) für KBr, oberhalb 400°C 0.6 eV (14 kcal/mol) für KCl und 0,4 eV (8 kcal/mol) für KBr.

Die Gasabgabe erfolgt unterhalb 400°C in den ersten 40 — 80 Minuten verzögert. Mit SrCl2 bzw. K2S dotierte KCl-Kristalle unterscheiden sich im Diffusionsverhalten nicht von KCl-Einkristallen. In den KCl-Tabletten beeinflussen geschlossene Poren die Edelgasabgabe.
Diffusion of Non-Gaseous Fission Products in UO2 Single Crystals II
Authors: Oi Noboru , Takagi Jinzaburo
Published: March 2015

The release of short-lived non-gaseous fission products from UO2 single crystals was studied in the temperature range of 1400 —2500°C by means of post-irradiation annealing. The release of the fission products studied appears to follow the kinetics of a diffusion process. Analysis of the data obtained gives the following diffusion constant,

DΜο = 3.9 × 10-4 exp(-54,000/RT), DI = 1.5 x 10-3 exp(-59,000/RT), DTe = 6.6 × 10-3 exp(— 70,000/RT), DLa (tentative) =2.2 x 10-6 exp (— 35,000/RT)

where the dimensions of D and RT are cm2/sec and cal/mol, respectively.
Bestimmung der Wärmeleitfähigkeit heißer Gase aus der Temperaturgrenzschicht im Stoßrohr
Authors: Smeets G.
Published: March 2015

Es wird eine Theorie der reinen Temperaturgrenzschicht entwickelt, wie sie sich nach der Reflexion der Stoßwelle am geschlossenen Ende des Stoßrohres ausbildet. Dann wird das Interferenzbild berechnet, das entsteht, wenn man die Temperaturgrenzschicht im Differentialinterferometer betrachtet.

Da die Temperaturgrenzschicht und deren Interferenzbild von der Wärmeleitfähigkeit des im Stoßrohr befindlichen Gases abhängen, kann man aus den Interferenzaufnahmen auf die Wärmeleitfähigkeit schließen. Es wird dafür ein allgemeines Verfahren angegeben. Dann wird am Beispiel der Luft die Wärmeleitfähigkeit im Temperaturintervall 1140°K < T < 6075°K und bei der Dichte ρ = 1/10 ρN bestimmt.
Modenselektive Eigenschaften einer planparallelen dielektrischen Platte als Reflektor eines Laserresonators
Authors: Gehrer G. , Röss D.
Published: March 2015

Die Resonanzeigenschaft eines dielektrischen Etalons führt bei seiner Anwendung als Reflektor eines Laserresonators zu einer starken axialen und transversalen Modenselektion. Es treten näherungsweise nur solche Moden auf, die Moden des Etalons selbst sind. Die Temperaturabhängigkeit der Verstärkungslinie führt bei einem Rubinlaser dazu, daß in einem Pumpimpuls mehrere Moden nacheinander emissionsfähig werden. Mit einer planparallelen Glasplatte als Reflektor ist es möglich, in einem Rubinlaser bei Zimmertemperatur nur jeweils einen axialen Mode gleichzeitig anzuregen.
Zur Entstehung von Nadelkristallen beim Aufdampfen
Authors: Wagner Wolf-Udo
Published: March 2015

Calculations are presented of the kinetics of beginning whisker formation from the gaseous phase. This is done for a simple mechanism involving the interaction of spiral growth about a dislocation and impurities. The radius of a whisker is found to be in most cases inversely proportional to the concentration of impurities in the vapour. Formulae are given for the transition from a simple growth spiral to the whisker. The particle density on the surface is computed. Reasons for the assumption of a quasistationary treatment are given. The expressions are modified to include the case of finite dwell periods of the particles.
Vierbein-Formulierung der Theorie des Schwerefeldes
Authors: Chao K. , Kohler M.
Published: March 2015

Bei den Darstellungen des Ricci-Tensors durch die Vierbeine wird ein asymmetrischer Tensor zweiter Stufe definiert. Sein symmetrischer Anteil ist der Ricci-Tensor und sein antisymmetrischer Anteil ist der MØLLERSche Tensor. Für das Schwerefeld im Vakuum wird der asymmetrische Tensor gleich Null angesetzt. Diese Formulierung ist äquivalent mit der Vierbein-Theorie von MØLLER. Die MØLLERSchen Bedingungen für ein orthogonales System werden untersucht
Irreversibilität im Rahmen der Liouville-Gleichung
Authors: Pfirsch D. , Priess S.
Published: March 2015

Im Rahmen des Vielzeitenverfahrens wird die Liouville-Gleichung für ein homogenes einatomiges Gas mit schwacher Wechselwirkung bis zur zweiten Ordnung im Wechselwirkungsparameter direkt, d. h. nicht im Rahmen der BBGKY-Hierarchie, gelöst. Die Lösungen gestatten eine gleichzeitige Diskussion der Η-Funktionen, die mit der N-Teilchenfunktion bzw. mit der aus der N-Teilchenfunktion durch Integration resultierenden Einteilchenfunktion oder Master-Funktion gebildet sind. Das Resultat führt zur Deutung der Irreversibilität im Rahmen der Liouville-Gleichung als Phasenmischung zwischen den einzelnen Systemen der durch eine Liouville-Funktion beschriebenen virtuellen Gesamtheit bzw. auch zur Deutung mittels des Priogogineschen Kaskadenmechanismus
Mehrkomponentige, stationäre Nichtgleichgewichtsströmung in einem MPD-Energiewandler
Authors: Mayser B. , Eichert K. , Siegert H. J.
Published: March 2015

Zur Erfassung kinetischer Vorgänge in einem magnetoplasmadynamischen (MPD-) Energiewandler wird ein Gleichungssystem zur Berechnung einer eindimensionalen Plasmaströmung mit vier Komponenten in einem senkrecht zur Strömung verlaufenden Magnetfeld angegeben. Dabei werden die im Plasma ablaufenden Ionisations- und Rekombinationsprozesse durch Reaktionsgleichungen beschrieben, die kein Gleichgewicht voraussetzen. Das vorliegende Gleichungssystem ist auf eine einzige hin- und rücklaufende Reaktion beschränkt, läßt sich aber ohne Schwierigkeiten auf mehrere Reaktionen erweitern. Das System wird zur Berechnung von Strömungen in MPD-Konvertern benützt. Das Strömungsverhalten für verschiedene Arbeitsgase und Impfsubstanzen bei mehreren Mach-Zahlen wird diskutiert
Hochfrequentes Rauschen von Elektronenlawinen und sein Zusammenhang mit dem Mechanismus des Kaltkathodenbogens
Authors: Prinzler Helmut
Published: March 2015

An Niederstrombögen mit kalten Metallelektroden treten sehr hohe Rauschspannungen auf, welche aus einer der Kathode vorgelagerten Dampfschicht stammen. Nimmt man an, daß die Erzeugung der Ladungsträger durch Lawinenprozesse in dieser Dampfschicht erfolgt, so ergibt eine Modellrechnung mit einer Ballung von ≈ 5 · 106 Elektronen pro Lawine Übereinstimmung mit der beobachteten Rauschspannung. Das hohe Rauschen wird durch die Korrelation der Ladungsträgerbewegung in einer Lawine hervorgerufen und verschwindet bei Frequenzen, welche groß gegen die Elektronenstoßfrequenz (≈ 3·1011s-1) sind. Eine Abschätzung des Energiebedarfes zwingt entweder zur Annahme einer hohen Startzahl (≈104 Elektronen pro Lawine) oder aber zur Annahme einer Ionisierung von angeregten Zuständen aus. Im letzteren Fall kann der für den Mechanismus erforderliche hohe Ionisierungskoeffizient einigermaßen plausibel gemacht werden.
Analyse kernmagnetischer Resonanzspektren vom Typ A2B2 mit Ergebnissen von para-disubstituierten Benzolen, Äthylengruppen und Pyrrol
Authors: Dischler B.
Published: March 2015

The analysis of A2B2 spectra, especially the assignment of lines is further treated. Explicit expressions for the A4 spectrum as a limiting case of an A2B2 spectrum have been calculated and are listed. The observation of multiple quantum transitions in an A2B2 system is reported. Spin coupling and shielding parameters are given for 30 para-disubstituted benzenes and some other compounds. For pyrrole an improved set of spin coupling parameters could be obtained, making use of the information from C13 satellites. Substituent effects for the meta spin coupling in paradisubstituted benzenes are derived. A correlation with the electronegativity of the substituent is demonstrated and some arguments for a theoretical treatment are discussed.
Über die Konzentrationsdepolarisation der Fluoreszenz von Fluorescein in Polymethylmethakrylat
Authors: Kawski A. , Krosnicka M.
Published: March 2015

Es werden für Fluorescein in Polymethylmethacrylat (0,001-n. HCl-Lösung mit 10% Äthanol) die Messungen des Polarisationsgrades in Abhängigkeit von der Konzentration des Farbstoffes durchgeführt. Die depolarisierende Wirkung der Sekundärfluoreszenz wurde mittels eines von GÁTI und SZALAY vereinfachten Korrektionsverfahrens berücksichtigt. In dem untersuchten Konzentrationsbereich (10-5—10-3 g/cm3) wurde eine geringe Depolarisation des Fluoreszenzlichtes beobachtet. Die Meßergebnisse wurden mit den Theorien von JABLOŃSKI und WAWILOV verglichen und die Radien der Wirkungssphären zu RJ=39 Å und RW=27,0 Å bestimmt. Das experimentell bestimmte Verhältnis RJ/RW=1,445 ist in guter Übereinstimmung mit der Relation RJ=3⅓ RW bei Anwendung des vereinfachten JABLOŃSKischen Modells mit Wirkungssphäre. Der aus der Überlappung der Absorptions- und Fluoreszenzspektren experimentell bestimmte FÖRSTERsche kritische Abstand R0 ist in guter Übereinstimmung mit dem aus der Konzentrationsdepolarisation gefundenen WAwiLovschen Radius RW.
Über die Isotopenzusammensetzung und über den Sitz der leichten Uredelgase in Steinmeteoriten
Authors: Hintenberger H. , Vilcsek E. , Wänke H.
Published: March 2015

Using newly developed techniques for the separate measurements of rare gases in different mineral components of stone meteorites, comprehensive investigations were carried out on meteorites containing primordial rare gases. For the bronzite chondrites Breitscheid and Pantar, we could prove that all main mineral components contain light primordial gases, probably this is also true for the carbonaceous chondrite Murray and for the achondrite Kapoeta. The light primordial gases are highly concentrated in the outmost layers of the single mineral grains. The ratios for 4He/3He and 20Ne/22Ne vary for different meteorites and also for different mineral components within a single meteorite. Both ratios shows a correlation with the diffusion coefficients of the minerals involved; the lighter isotope being always more depleted in those minerals with the higher diffusion losses. According to the observed diffusion losses, the original primordial Helium content of Pantar comes out to be at least about two orders of magnitude higher than at present. For the true and original elemental and isotopic ratios we obtained values of 13.8 and 14.0 for 20Ne/22Ne, 2200 for 4He/3He and 800 for 4He/20Ne. These ratios have been altered considerably on account of gas losses by diffusion.
Unelastische Streuung niederenergetischer Elektronen an Methan, Propan und n-Heptan
Authors: Ehrhardt H. , Linder F. , Meister G.
Published: March 2015

The inelastic scattering of 70 eV electrons (0.3 eV half width) by methane, propane, and nheptane has been measured in the angular range of 0 to 145°. From these data the relative total cross sections versus energy loss of the electrons for propane and n-heptane are calculated The energy distributions of the scattered electrons and the electrons ejected during the ionization processes are largely separated. In the case of n-heptane the ratio of the total number of processes leading to neutral excited states and the total number of processes leading to ionized states is determined. About 25% of the neutral excitations have energies below the first ionization potential, 75% above. Electronic levels of the ionized species are observed; some of them have been predicted by MO calculations. The amount of vibrational energy transferred to one electronic state is discussed, and the rapid change of the form of the energy transfer function with temperature (from 50 to 850°C) is experimentally demonstrated.
Zur Kristallstruktur von Proben der Nb3Sn-Phase mit unterschiedlichen Sprungpunktstemperaturen
Authors: Pfister H.
Published: March 2015

Aus der Gasphase hergestellte Proben der Nb3Sn-Phase mit unterschiedlichen Zusammensetzungen bzw. Sprungtemperaturen wurden röntgenographisch untersucht. Intensitätsmessungen des 110-Überstrukturreflexes ergaben, daß bei Abweichungen von der Stöchiometrie die überschüssigen Nb-Atome auf Sn-Gitterplätzen eingebaut werden. Eine Gitterunordnung wurde in keinem Fall festgestellt.
Notizen: Enrichment of Tritium by Diffusion through Palladium
Authors: Charalambus S. , Goebel K.
Published: March 2015

The different diffusion velocities of Hydrogen and Tritium through Palladium open the possibilities of Tritium enrichment in the residual gas mixture. The relative diffusion velocity of Tritium versus temperature and the enrichment related to the initial and final quantities of the mixture as well as the diffusion temperature are described.
Untersuchungen über die statistischen Schwankungen der infraroten Strahlung einer Hochdruck-Hochstrom-Argonentladung
Authors: Gubler W. , Strutt M. J. O.
Published: March 2015

An argon discharge at high pressure (up to 20 atmosph.) and large dc current is described. This discharge is used in the investigation of spontaneous fluctuations of photon radiation. Electron and ion densities are calculated as functions of pressure and temperature from which the continuous emission and absorption coefficients are determined. By comparing the calculated emission with the measured distribution of the infrared spectral radiation intensity in a disk of plasma, which is 0,2 mm in front of the cathode, the radial temperature distribution in the disk is determined. The temperature in the arc axis was found to be independent of the gas pressure and must be higher than 28 000°K. Investigations on electrical conductivity confirm the temperature distributions. Finally, the statistical radiation fluctuations can be calculated by means of the equations given in Part I and are compared with the experimental results. The infrared detector used for all these measurements is also described in Part I. A satisfactory coincidence between calculated and measured values was found.
Space-correlation Function Expression for the Real Part of the Electrical Conductivity
Authors: Gabriel Helmut
Published: March 2015

The real part of the frequency and wave-vector dependent conductivity is expressed in terms of single-particle and pair correlation functions starting from a generalized KUBO formula. The result is an analogon to ZWANZIG'S relation between the self-diffusion coefficient and the dynamical structure factor introduced by VAN HOVE in the theory of neutron scattering. As an application we calculate the real part of the mobility for the small polaron.
Anwendung der 13-Momenten-Näherung auf das Problem der Run-Away-Elektronen
Authors: Hertweck Friedrich
Published: March 2015

The non-linear 13 moment approximation is applied to the problem of run-away-electrons. The solution is compared with the results obtained by DREICER.
Über Stabilität und Liganden-Austauschgeschwindigkeit der Hexachloro- und Hexabromo-Komplexe des Technetium (IV) und Rhenium (IV)
Authors: Schwochau Klaus
Published: March 2015

Komplexbildungskonstanten und Liganden-Austauschgeschwindigkeiten der Hexachloro- und Hexabromotechnetate (IV) und -rhenate(IV) wurden unter jeweils vergleichbaren Bedingungen bestimmt. Die Bildungskonstanten k6 ergaben sich für [TcCl6]— und [TcBre]— nahezu um den Faktor 50 kleiner als für die entsprechenden Re-Komplexe. Die nach Markierung mit 36Cl bzw. 82Br gemessenen Austauschraten der Chloro- und Bromotechnetate sind fast 20- bzw. 50-mal höher als die der analogen Re-Verbindungen. Die Aktivierungsenergien der Austauschreaktionen wurden ermittelt.
Time-Resolved Profile Measurements of Impurity Lines in a Theta Pinch Discharge
Authors: Eberhagen A. , Bernstein M. J. , Hermansdorfer H.
Published: March 2015

Line profile measurements were carried out on a small theta pinch experiment in order to get information on the ion motions during the discharge. A FABRY-PEROT interferometer combined with a so-called Fafnir arrangement was used for measuring the shape of the investigated N V (4603 Å) and O VI (3811 Å) lines. The additional use of a polarizer and λ/4 plate made it possible to eliminate ZEEMAN splitting caused by a magnetic field present, which affects the line shape, and to measure the magnitude of the magnetic field strength at the site of line emission in the plasma. By means of a combined system comprising image converter and intensifier the emission regions of the investigated lines in the plasma could be identified. The experimentally obtained results are discussed considering the different influences leading to line broadening in the present experiment.
Zur paramagnetischen Elektronenresonanz metallorganischer Sandwich-Verbindungen,Teil lI
Authors: Nussbaum Manfred , Voitländer Jürgen
Published: March 2015

On the basis of the ionic model of ROBERTSON and MCCONNELL the energy levels and the wave functions of Ni (C5H5)2 are calculated quantitatively and the magnetic resonance properties derived from them. The results explain the fact that no ESR spectrum of the compound has been observed up till now. The calculations for Co (C5H5)2 show that the magnetic resonance effect is strongly dependent on the magnitude of the rhombic distortion (JAHN-TELLER effect) compared to the spinorbit coupling. The hyperfinestructure spectrum of a magnetic-diluted single crystal is qualitatively explained.
Energietransport zwischen Rekombinationszentren des Mn, Fe, Co, Ni und Cu bei der Elektrolumineszenz von ZnS-Phosphoren
Authors: Gumlich H.-E. , Moser R.
Published: March 2015

The transport of energy between Mn, Fe, Co, Ni, and Cu recombination centers in ac-electroluminescence of ZnS-phosphors has been investigated. The exchange of energy is explained to be due to hole migration via the valence band: during any cycle of the voltage electrons and holes are separated temporarily and recombine only after the direction of the electric field is reversed. The delay of recombinations gives rise to a change of the distribution of holes over the activators. Shortly after excitation the holes are distributed according to the capture cross sections. When the field is reversed within this period the recombinations take place in centres with high capture cross section. However when the frequency of the electric field is low and the temperature is so high that holes can be liberated by thermal energy, the holes are distributed following the FERMI-Statistics. The change of hole distribution has been studied by varying frequency, temperature and voltage.
Zentralsymmetrische statische Schwerefelder mit Räumen der Klasse 1
Authors: Kohler M. , Chao K. L.
Published: March 2015

Einbettungsfragen wurden in der Relativitätstheorie bisher selten betrachtet, da sich sofort die Frage nach der physikalischen Natur der Variablen des Einbettungsraumes stellt. Es gibt aber Fälle, wo sich das Einbettungsproblem von selbst stellt, das sind die Räume der Klasse 1, mit dem Rang ≥ 3 der 2. Fundamentalform bαβ dxα dxβ, da dann der 2. Fundamentaltensor bαβ aus der Metrik bestimmbar und der bαβ ein Tensor des Schwerefeldes wird. Behandelt sind nur zentralsymmetrische, statische Linienelemente, wo der Rang von bαβ gleich 4 ist. In diesem Fall folgen die Codazzi-Gleichungen aus jenen von GAUSS und brauchen nicht explizit berücksichtigt zu werden. Die Komponenten des RIEMANN–CHRISTOFFELSCHEN Tensors und die bαβ lassen sich in nichtrationaler Weise durch jene des EINSTEIN-Tensors Gαβ ausdrücken, wobei sich gewisse Bedingungen für die Gαβergeben, damit reelle Werte für die anderen Tensoren folgen. Die Anwendung auf das Schwerefeld einer Flüssigkeitskugel ergibt 2 Lösungen der Klasse 1, wobei eine davon die Innenlösung von SCHWARZSCHILD ist. Im letzten Abschnitt wird schließlich gezeigt, daß die Einbettung im 5-dimensionalen pseudoeuklidischen Raum dieselben Formeln für die bαβ liefert, die vorher ohne Bezugnahme auf die Einbettung gewonnen wurden.
Zur Berechnung von spezifischer Wärme und Entropie in der Quantenstatistik
Authors: Wagner F. , Koppe H.
Published: March 2015

Applying the variational principle of BOGOLIUBOV to calculate the free energy of a quantum system one does not get, automatically, physical meaningful results for entropy and specific heat. By using the temperature in the ansatz for the statistical operator as a variational parameter it is proved, that at any rate, the approximation expression for free energy has the properties of a thermodynamic function, that means, it leads to positive values for specific heat and entropy, and to a GIBBS—HELMHOLTZ equation for entropy and free energy.
Convergent S. C. F. Wave Function and Properties of the Ammonia Molecule
Authors: Rajagopal P.
Published: March 2015

A self consistent field wave function calculation for the ammonia molecule by the technique of accumulative accuracy is described. The molecular integrals required are calculated by numerical integration methods. Total and dissociation energies, dipole and quadrupole moments and ionization potentials calculated using the wave function are reported. The proton affinity of NH3 is also estimated.
Neutron Cross Sections for Some Threshold Reactions
Authors: Lagerwall Torbjörn
Published: March 2015

Three neutron reactions leading to production of the rare gases Ar41 and Xe135 have been investigated. Single crystal samples of KF, CaF2, and BaF2 were irradiated in the Berlin reactor and the target-free absolute activities of the rare gas isotopes measured by a β-γ-coincidence method. The calculated cross sections are

K41(n,p) Ar41: σ= ( 2,73±0,41) mb; σ0= (98,6±14,8) mb;

Ca44 (n,a)Ar41: σ = (61,1 ±9,2) μb; σ0= (64,7± 9,7) mb;

Ba138(n,a)Xe135: σ= ( 1,9 ±0,3) μb; σ0= ( 4,9± 0,7) mb.

The first set of values are valid for a fission-neutron spectrum. The second set are calculated cross sections for the high energy plateau. They can be considered as valid for 15 MeV neutrons.
Theoretical Efficiency of a Thermionic Diode
Authors: Shaked Hagai
Published: March 2015

A theoretical analysis of the efficiency of a thermionic diode is made in the highly efficient region of very low anode potential (Va<1 volt). Maximum efficiency is calculated as a function of the cathode temperature for optimum values of anode potential. The calculations are performed for different values of usuable power density, anode temperature and emissivity of electrodes.
Der Einfluß der Anordnung von Schraubenversetzungen auf die Gitterwärmeleitfähigkeit bei tiefen Temperaturen
Authors: Gruner Peter
Published: March 2015

Mit Hilfe der nichtlinearen Elastizitätstheorie wird der thermische Widerstand durch Schraubenversetzungen, die in bestimmter Weise angeordnet sind, berechnet. Es zeigt sich dabei, daß in Kupfer oberhalb der Temperatur des flüssigen Heliums die Art der Anordnung keine Rolle spielt und der Wärmewiderstand der Versetzungsgruppe in guter Näherung gleich ist dem bei statistisch verteilten Versetzungen. Unterhalb von etwa 4°K findet man, daß die Wärmeleitfähigkeit stärker als quadratisch mit zunehmender Temperatur ansteigt.
Investigation on the Rare Earth Terpyridyl System
Authors: Sinha Shyama P.
Published: March 2015

The preparation of terpyridyl chelates of heavier rare earths of the type M (Terp) (NO3)3 ·n H2O(M = Tb — Yb and n = O —3) is described. The infrared studies of the solid chelates show the coordinated nature of both terpyridyl and nitrate groups. A spectrochemical series based on the shift of the “breathing” vibration of terpyridyl in the complexes is proposed.
Mikrowellenspektrum, Struktur, Dipolmoment und internes Hinderungspotential von Dimethyldisulfid
Authors: Sutter D. , Dreizler H. , Rudolph H. D.
Published: March 2015

The microwave spectra of CD3 —S —S —CD3 and CH3 —S —S—CH3 have been measured in the frequency range from 5.5 to 34 kmc/sec. From the six rotational constants an r0-structure has been calculated. STARK-effect measurements have been made for the 101 —110 and 202—211 rotational transitions of CH3—S—S—CH3. The dipole moment was calculated to be (1.985±0.01) Debye. An approximate value for the barrier to internal rotation of the two methyl tops is given, V3= (1.6±0.1) kcal. The calculation has been based on triplet splittings of the rotational lines using second order perturbation theory in the torsional wavefunctions and neglecting first order and cross terms in angular momentum.
Mikrowellenspektrum, Hinderungspotential der internen Rotation und Dipolmoment des para-Fluortoluols
Authors: Rudolph Heinz Dieter , Seiler Helmut
Published: March 2015

The microwave rotational spectrum of para-fluoro-toluene has been investigated in the region from 7 to 31 kmc/s. The three types of absorption lines to be expected in the case of a molecule of this type, i. e. with a very low sixfold barrier hindering the internal rotation of the methyl group, have been found: m=0, | m | ≠ 0, 3 n, | m | = 3 n. From the lines m=0 the rotational constants and the dipole moment, (1.96 ± 0.02) D, have been deduced; from the lines |m|=3 the internal rotation barrier could be calculated as V6=13.82 cal/mole. This V6 is compared with the values found for similar molecules.
Über den Ablauf des Θ-Pinchs bei höheren Ausgangsdichten
Authors: Meiners Dieter
Published: March 2015

A linear θ-pinch discharge without preionization is investigated in Helium within that range of density, in which the mean free path of electrons between two elastic collisions diminishes to such a low value that the electrons cannot gain the ionization energy in the induced electric field over this distance. Compared to the well known observations at low densities in this high density range the instant of the first breakdown in the discharge tube is found to be shifted to later halfcycles with increasing initial pressure. In addition, the further development of the discharge at high initial densities shows a very different structure compared to the low density behaviour. Comparison of optical observations with measurements of the current density distribution obtained by means of magnetic probes (using a special difference method on account of the very small plasma currrents) shows the following result: In the half cycle immediately following the breakdown, a typical shock wave pinch is produced at high densities. The regions near the axis are heated only by an ionizing shock, while the contraction of the current sheath, which initially started the shock, is stopped very early in far outer regions. During the following half-cycle quite a different behaviour of the discharge is observed on account of the enhanced electrical conductivity: The contraction runs much faster and therefore the separation between the shock front and the driving current sheath decreases.
Mass Spectrometry: The Elimination of CO from Substituted Nitro Naphthalenes
Authors: Beynon J. H. , Job B. E. , Williams A. E.
Published: March 2015

The mass spectra of 1-nitronaphthalene, 2-nitronaphthalene and eight substituted nitro naphthalenes have been studied. The loss of neutral CO from the molecular ions of these compounds has been established by high resolution techniques and study of “meta stable” peaks. The probability of elimination has been related to the electron density at the 8-position.
Spectroscopic Studies of Molecular Constants in some Polyatomic Molecules
Authors: Nagarajan G.
Published: March 2015

Force constants have been evaluated by the WILSON group theoretical method for various ij3 molecules possessing a planar trigonal symmetry. Mean-square amplitude quantities and mean amplitudes of vibration for the bonded as well as nonbonded atom pairs have been computed at the temperatures T=0 and T=298 °K for C3 , Si3 , and XeF2 by the CYVIN method. The molar thermodynamic functions from spectroscopic data have been calculated for Si3 and XeF2 on the basis of a rigid rotator, harmonic oscillator model. BASTIANSEN-MORINO shrinkage effects have been calculated for various linear asymmetrical ijk, linear symmetrical ij2 and tetrahedral ij4 molecules at the temperatures T=0 and T=298 °K.
Über das Dissoziationsgleichgewicht realer Gase
Authors: Koppe H. , Spies G.
Published: March 2015

The quantum mechanical cluster expansion, when applied to the partition function of a gas consisting of atoms whose bound states are the rotational and vibrational states of diatomic molecules, provides an exact expression for the degree of dissociation. The approximation containing only the second cluster integral is shown to be identical with the law of mass action involving the binary collision approximation for the activity coefficient of the dissociated constituent. This coefficient can be calculated from the phase shifts and thus from the cross sections of the elastic atom-atom-scattering.
Self-Diffusion in Molten Silver Nitrate
Authors: Sjöblom C.-A. , Andersson J.
Published: March 2015

The self-diffusion coefficient of the Ag+-ion in molten AgNO3 has been measured with the glass fibre paper strip technique in the temperature interval 220—336 °C. The result can be described by the equation

D=3.2 × 10—4 exp{-3400/(RT)} cm2s—1.

A comparison with the results obtained by other workers shows good agreement between the two sets of values. Possible sources of error are discussed.
Zur F – F′-Reaktionskinetik in KCl
Authors: Wille Hans , Wahl Friedrich
Published: March 2015

Für die F—F′-Reaktionskinetik in Alkalihalogeniden wird ein Modell für den Übergang des Elektrons aus dem angeregten Zustand des F-Zentrums ins Leitungsband vorgeschlagen und quantitativ ausgewertet. Es handelt sich bei diesem Modell um einen optischen Übergang, der durch Absorption eines Lichtquants aus einem mit den transversalen optischen Gitterschwingungen in starker Wechselwirkung stehenden Strahlungsfeld zustande kommt. Ein direkter strahlungsloser Übergang ist auf Grund der zugehörigen Auswahlregeln verboten. Da das Dispersionsgesetz im Bereich der Resonanzfrequenz von Gitter und Strahlungsfeld sehr stark von dem des freien Strahlungsfeldes abweicht, und diese Frequenz gerade in der Größenordnung der erforderlichen Absorptionsenergie liegt, kommt der erwartete Übergang tatsächlich mit hoher Wahrscheinlichkeit zustande. Die Temperaturabhängigkeit der Quantenausbeute für diesen Prozeß steht in guter Übereinstimmung mit dem für KCl experimentell ermittelten Verlauf.
On the Temperature Dependence of Multi-Alkali Photocathodes
Authors: Hora H. , Kantlehner R. , Riehl N. , Thoma P.
Published: March 2015

Measurements of the temperature dependence of the photoemission from multi-alkali cathodes down to 77.4 °K are described. The general shape of the measured characteristics is compared with curves obtained by other authors for cathodes of different origin. It is found that the properties of the cathodes depend on the preparation method. In all measurements, decrease of photoemission with decreasing temperature is a property common to all cathodes if the trivial case of insufficient transverse conductivity can be eliminated. It is shown that this property may be connected with possible emission from acceptor levels in the long wavelength tail range.
Erzeugung energiereicher Plasmen durch Lichtimpulse
Authors: Opower H. , Press W.
Published: March 2015

Light pulses from a Q-switched laser with a peak power of 250 MWatts and 3.5 joules are focussed on carbon and LiH targets in a vacuum chamber. Thereby a rapidly expanding plasma is formed. The expansion velocities of the electrons and ions are nearly equal. By means of an electric field the electrons are drawn out of the plasma; the ions are detected in a FARADAY box. From time of flight measurements particles with a maximum energy of 6.3 keV are found in the case of carbon and 1.7 keV in the case of LiH (average mass number=4). The high values of the ion energies result from an energy transfer from the electrons to the ions during the expansion process. This energy transfer is explained by a simple electrostatic model. If the averaged ion energy is equally distributed to all particles of the plasma (electrons and ions), a mean energy of 340 eV per particle is obtained for a LiH target and 550 eV for a carbon target. These values are 5 times higher than the data previously reported. The number of expanding ions in a solid angle π is determined to be about 2.1015 in the case of LiH. The total kinetic energy of these ions is about 0.3 joules. It is hoped, that by an increase of the energy by a factor 4 and the use of a D—T mixture nuclear fusion reactions will be obtained.
Ionisationsgleichung für optisch dünne Plasmen
Authors: Bohn W. L.
Published: March 2015

An ionization formula for optically thin plasmas is proposed taking into account collisional ionization and both collisional and radiative recombination.

This rather simple formula allows the calculation of the plasma components over the whole range of electron densities and temperatures. In cases of extremely low or extremely high electron densities it approaches the well known corona, and SAHA-equation (for electron temperature), respectively. Furthermore it is shown that the SAHA-equation is not valid in a high temperature plasma having a great ionic charge even at high electron densities, and that the proposed ionization formula should be used. Results at constant pressure or constant electron density are given in numerous diagrams.
Investigation of the Cyclotron Harmonic Radiation from a Plasma in a Magnetic Field
Authors: Räuchle Eberhard , Hess Walther
Published: March 2015

The microwave emission of the positive column of a low pressure discharge in a magnetic field is investigated by means of a 10 000 Mc/sec radiometer. The radiation intensity as a function of the longitudinal magnetic field shows a number of peaks near the electron cyclotron harmonic frequencies. The measurements are performed for noble gases in the pressure range from 10 to 10-2 Torr at electron densities varying from 109 to 1013 cm-3. In order to compare the experimental results with a theoretical investigation performed by one of the authors12, the emission of harmonics was observed in dependence on the electron density. A satisfactory agreement between theory and experiment is shown.
Spallation, Fission, and Neutron Capture Anomalies in Meteoritic Krypton and Xenon
Authors: Marti K. , Eberhardt P. , Geiss J.
Published: March 2015

Measurements of the Kr and Xe concentrations and isotopic compositions in five meteorites are reported. Experimental techniques and reproducibility are discussed in detail. In the Stannern achondrite 75% of the total Kr and 30% of the total Xe are due to cosmic ray induced spallation reactions. Also Bruderheim and H - Ausson show distinct spallation components. The isotopic composition of pure spallation Kr is derived as Kr78 : Kr80 : Kr82 : Kr83 : Kr84 = 0.179 : 0.495 : 0.765 : 1.00 : 0.63

and of spallation Xe as Xe124 : Xe126 : Xe128 : Xe130 : Xe131 : Xe132 = 0.590 : 1.00 : 1.45 : 0.97 : 3.9 : 0.9. It is shown that the spallation components found were produced by the cosmic radiation late in the history of the meteorite during a period given by the radiation age. The observed Xe128/Xe124 spallation ratio rules out a substantial contribution of spallation products in the xenon of carbonaceous chondrites. The Xe fission spectrum derived by ROWE and KURODA from Pasamonte is corrected for spallation and the following composition is obtained for fission Xe : Xe131 : Xe132 : Xe134 : Xe136· = 0.22 : 1.00 : 1.02 : 1.00.

In Mezö-Madaras and Abee Kr80, Kr82 and Xe128 excesses are found, due to (n.γ) reactions on Br and I. It is shown that neutrons produced by the cosmic radiation during the radiation age can account for the observed effect in Abee and the evidence so far suggests that this is also true for Mezö-Madaras.
Das Mikrowellenrotationsspektrum des SnSe
Authors: Hoeft J.
Published: March 2015

In einem konventionellen Mikrowellenspektrometer mit heizbarer Absorptionszelle gelang die Beobachtung des reinen Rotationsspektrums einer weiteren (IV/VI)-Verbindung. Im Frequenzbereich 11—35 GHz wurden bei Temperaturen zwischen 650 und 700 °C Rotationsübergänge von 29 Isotopenkombinationen des SnSe gemessen. Es werden Rotationskonstanten, Kernabstände und Massenverhältnisse von Zinn- und Selenisotopen mitgeteilt. Für den Kernabstand des SnSe ergab sich der Wert re = (2,325603 ± 0,000070) Å.
Über die Reichweite von Triplett-Excitonen in reinem geschmolzenem Naphthalin
Authors: Bässler H.
Published: March 2015

In connection with the preceeding paper measurements are reported concerning the photocurrent arising in molten naphthalene with intense illumination. It has been shown that irradiation in the spectral regions of the forbidden singlet-triplet absorption band and of the longwave edge of the singlet absorption band can produce triplet excitons in the bulk of the liquid. If the incident light is parallel to the electrodes, it is able to build up a nearly homogenous distribution of excitons in a layer parallel to the electrodes. By variation of the distance of the layer from the anode one can get information about the migration and the diffusion length of the triplet-excitons, because they can only contribute to the conductivity if they have reached the anode and have dissociated there. The experiments demonstrate that in forty-times zone-refined molten naphthalene (oxygen pressure less than 10-2 Torr) the diffusion length of triplet excitons is about 1 cm. The migration obeys a diffusion law with a diffusion constant D= 1.5 cm2 sec-1 (error: factor 2). From the rise and decay times of the photocurrent it follows a mean life time τ = (0.4 ± 0.2) sec of the triplets in the limiting case of neglegible dissociation. The probability of primary dissociation is about 0.3 (error: factor 2). Because of the high recombination probability only a small part of the produced cations can move to the cathode, so that the resulting dissociation probability is much lower. The results cannot be explained by assuming diffusion of an excited molecule but demand the assumption of a high hopping probability of the triplet state in a pure liquid aromatic compound.
Über den Einfluß von Fänger- und Löschmolekülen auf die Reichweite von Triplett-Excitonen in geschmolzenem Naphthalin
Authors: Bässler Heinz
Published: March 2015

Recently it was found that in zone-refined, molten naphthalene triplet-excitons are able to diffuse over a distance of about 1 cm. This diffusion length can be greatly reduced by addition of quenchers. If the quenching molecules have a triplet level lying below the level of the host (energy difference ΔΕ), they can trap the exciton. For ΔE ⪅ 0.5 eV the probability that the exciton is released thermally and given to the host molecules again, exceeds the desactivation probability. Therefore the quencher only acts in slowing down the mean velocity of the moving exciton, the life-time remains constant. In this case enhancement of the photocurrent in naphthalene can be obtained by additional excitation of the S1 state of the quencher followed by intersystem-crossing and population of the desactivation probability of neighbouring host-molecules. Therefore the life-time of the excitons electrons increases.

Molecules wih a T1-state above the T1-state of the host can quench the exciton-motion, too, if the life-time of their T1-state is reduced by spin-orbit-coupling (p-dichlorbenzene). They increase the desactivation probability of neighbouring guest-molecules. Therefore the life-time of the excitons decreases.

A model is proposed predicting the decrease of the diffusion length with quencher-concentration according to

, which is in good agreement with the experiments. Thereby energy-transfer is presumed to be proportional to c. Finally it is reported that guest-molecules with higher electron-affinity can produce a cathodic photoeffect, too, by forming cations.