bluuebunny/crossref_metadata_2025 huggingface dataset:
Streuung schneller Elektronen in einem Gasplasma/Scattering of Fast Electrons by a Gas Plasma
Authors: Boersch H. , Geiger J. , Topschowsky M.
Published: February 2015

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

n- and p-type Germanium at 77 °K has been irradiated by 14 MeV-neutrons and subsequently annealed. The results are compared with those obtained from reactor irradiated materials.

The observed changes of Hall-constant and electrical resistivity of n- and p-type Ge can be de-scribed by the disordered regions model.

In p-Ge the disordered regions decay by isochronal annealing between 77 °K and 230 °K. This process is superposed by the process of the creating and the decay of a type of defect that has also been observed after electron irradation.

After reactor-neutrons irradiation n-Ge shows a reverse annealing between 100 °K and 150 °K. In this temperature interval no steady state annealing effects have been observed after 14 MeV-neutrons. It is suggested that during each annealing stage vacancies diffuse out of the defect zones and are trapped by small defect clusters in reactor irradiated n-Ge. In 14 MeV irradiated material nearly no such small clusters are present, so the vacancies diffuse until they are retrapped by the disordered regions. The process of back diffusion can be measured. It obeys an exponential law. Between 150 °K and 230 °K after either type of irradiation a reverse annealing takes place. It is suggested that in this annealing interval the defects of the disordered regions become divacancies.
Notizen: Die Rotation der γγ-Winkelkorrelation der Kaskaden (570 – 797) keV, (570 – 797 – 605) keV und (797 – 605) keV von Ba134 in einem äußeren Magnetfeld/ The Rotation of the γγ Angular Correlation of the Cascades (570–797) keV, (570–797–605) keV and (797–605) keV of Ba134 in an External Magnetic Field
Authors: Beer H.
Published: February 2015

The over all γγ angular correlation of the cascades (570-797) keV, (570-797-605) keV and (797-605) keV in Ba134 was perturbed by an external magnetic field of 41.4 kG perpendicular to the directions of observation of the quanta. The rotation of the angular correlation was found to be

ωτ=0.05±0.03 .

This result could be due to the 2+ 605 keV or te 4+ 1400 keV energy level or to both level with measurable portion. The aspects of these alternatives are discussed.
Hyperfeinstruktur, Stark-Effekt und Lebensdauern in den angeregten 5d6s6p y2D3/2,5/2 -Zuständen des Lanthan I-Spektrums/ Hyperfine Structure, Stark-Effect and Lifetimes of the Excited 5d6s6p y 2D3/2,5/2-States of the Lanthanum I Spectrum
Authors: Hese A. , Büldt G.
Published: February 2015

The levelcrossing method has been used for an investigation of the hyperfine structure and lifetimes in the excited 5d6s6p y 2D3/2, 5/2-states of Lanthanum I. From a detailed analysis of the measured change in intensity of the resonance light the following hyperfine interaction constants and lifetimes were deduced:

Applying an additional homogeneous electric field parallel to the usual magnetic field the constants β of the quadratic Stark effect in the y 2D-states were derived from the observed shifts of the levelcrossing signals:

The experimental results are interpreted theoretically by the concept of intermediate coupling using appropriate eigenvectors. The observed lifetimes and the β-values are compared with the Bates and Damgaard approximation.
Symmetry Conditions on Nonlinear Spinor Field Functionals/The symmetry conditions of nonlinear spinor theory of elementary particles, i.e. the definitions of quantum numbers, are given for the nonlinear spinor field functionals.
Authors: Stumpf H. , Scheerer K. , Märtl H.G.
Published: February 2015

The operator equations of quantum theory can be replaced formally by functional equations of corresponding Schwinger functionals 1-3. To give this formalism a physical and mathematical meaning one has to develop a complete functional quantum theory as has been proposed in a preceding paper4. Then the complete physical information has to be given by functional operations only. Especially the quantum numbers of ordinary quantum theory have to be reproduced functionally. As the quantum numbers are defined by the eigenvalues of the generators of the corresponding invariance groups, one has to investigate these quantities in functional space. This is done in this paper. To have a definite model we consider the nonlinear spinor field with noncanonical relativistic Heisenberg quantization 5 the form invariance group of which is the Poincare group. Although this model has still other symmetry properties we restrict ourselves to the discussion of the quantum number conditions resulting from this group, as the considerations for other groups and models are quite analogous.
Zur Begrenzung der radialen Ausdehnung des Lichtbogenstromes durch ein axiales Magnetfeld
Authors: Klüber O.
Published: February 2015

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

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

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

The nuclear magnetic relaxation times T1 and T2 may be determined by observing the relaxation that follows after a stop of an adiabatic fast passage at different points of the resonance signal.

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

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

Experimental dynamic nuclear polarization (DNP) studies at 176 gauss, 3420 gauss, and 13 200 gauss and at various temperatures have been concerned with the Overhauser effect of solvent carbon-13 nuclei in solutions of free radicals. Detailed measurements have been made in solutions of benzene and methyl iodide. The relative importance of scalar and dipolar coupling, the correlation times and spectral intensity functions have been of the greatest interest. The importance of the “three-spin-effect” has been investigated by applying triple-resonance irradiation. Dipolar and scalar hyperfine couplings between carbon-13 nuclei and odd electrons are of comparable magnitude, where the main difference of the DNP enhancement factors is caused by different shapes of the spectral intensity function for the fluctuations of the scalar interaction. The results are discussed in terms of the molecular structure and of the collision attitudes.
Valence Force Constants and Normal Vibrations of Methanol
Authors: Timidei A. , Zerbi G.
Published: February 2015

The possibility of reproducing the normal vibrations of methanol, CH3OH, and its deutero-derivatives CH3OD, CD3OH, CD3OD using a valence force field has been critically analyzed. A 13 parameter valence force field has been determined by least square calculations. The meaning of the obtained numbers and their validity in molecular spectroscopy are discussed and compared with the information already available in the literature. It is concluded that the vibrational modes of this molecule are fairly well known within the harmonic approximation.
Decomposition of Equimolar NaBr-KBr Mixed Crystal
Authors: Ahtee M. , Inkinen O. , Koski H. , Pehkonen S.
Published: February 2015

The decomposition of equimolar NaBr-KBr mixed crystal has been studied within a temperature range of 115 to 251 °C. The measurements were made with an apparatus suitable for continuous recording of the changes in specimen capacitance. The results indicated that the decomposition takes place in three steps. A report is made on the decay constants, half-lives, and activation energies of the first two steps - the nucleation of a freshly prepared specimen, and the subsequent decomposition of the nucleated mixed crystal into components which are nearly pure. It was found that above 150 °C the rate of these processes is affected by a temperature-dependent effect of do-main formation. The experimental result for the activation energy associated with the processes, 0.84 ± 0.05 eV, compares favourably with the value derived from a simple diffusion model.
Notizen: On a New Theory of the Magnetization Curve of Plastically Deformed Nickel Single Crystals
Authors: Markert H.
Published: February 2015

A new theory of the magnetization process in plastically deformed nickel single crystals of single slip orientation is outlined. It is based on the interaction between the (101)-180°-domain walls and the three types of primary edge dis-location dipole and multipole arrangements dominating in stage I, in the transition region and in stage II of the stress-strain curve, respectively, i.e. the [121]-dipole bundles, the rope-like clusters of such bundles extended along [121], and the [121] -multipole walls, all having [T01]-Burgers-vectors. In increasing magnetic fields the primary edge dislocation arrangements are shown to be capable to glide to new ob-stacles under the pressure of the (101) -180°-domain walls which will follow them and whose segments at the same time start to vault themselves cylindrically or pillow-shapedly be-tween these dislocation barricades, finally overcoming them at the coercive force by Barkhausen jumps. In an earlier paper 1 first experimental results had been reported concerning the large decrease of num-ber and size of Barkhausen jumps observed on samples of plastically deformed nickel and on magnetite dur-ing simultaneously superposed intensive ultrasonic ir-radiation. To explain this unexpected effect in terms of domain wall motion, an attempt had been made to mo-dify the usual potential theory of the magnetization curve by introducting a new hypothetical magnetization process which should enable the domain walls also to move to some extent irreversibly and continuously but without Barkhausen jumps. In the meantime, the mentioned problems were sub-ject of a recently published extensive dissertation 2 which contains, in addition to a more detailed descrip-tion of the experiments and of the apparatus used, also the analysis of the main consequences of these experi-mental facts with respect to the usual potential theories of the magnetization curve of deformed nickel, showing the strong inconsistency between these theories on the one hand and the experimental results, reported in 1 and 2 , and certain other important empirical facts on the other. Last not least this dissertation contains a new consistent quantitative theory of the magnetization curve of plastically deformed nickel single crystals of single slip orientation. The aim of this note is to summarize in a qualitative manner the main statements of that new theory. Its basic assumptions which could be proved by quoting numerous experimental facts as well as by detailed quantitative estimations are the following ones:
Notizen: Microwave Spectrum of BaO
Authors: Hoeft J. , Lovas F.J. , Tiemann E. , Törring T.
Published: February 2015

Observation of the J=1 → 2 rotational transition of BaO in a microwave absorption spectrometer at 1700 °C is described. For 135BaO and 137BaO the nuclear electric quadrupole constants, e q0 Q, in the ground vibrational state are reported.
Notizen: The Ternary System K(CNS, HCOO, NO3)
Authors: Berchiesi Gianfrancesco , Cingolani Augusto , Leonesi Dante
Published: February 2015

As a part of our current researches, we report in the present paper on solid-liquid equilibria in the K (CNS, HCOO, N03) ternary system. Experimental
Notizen: Abschätzung der Frequenzen des IR-Spektrums des Schwefeldifluorids/Estimation of the IR-Frequencies of Sulphurdifluoride
Authors: Bliefert C. , Wanczek K.-P.
Published: February 2015

The theoretical IR-frequencies of sulphurdifluoride are computed from force constants, which are evaluated by means of molecules with S-F-bonds:

ν1 = 795 ± 10cm-1, ν2 = 430± 5cm-1, ν3= 830 ± 10cm-1.
Strain Effects on the Tunneling Levels of KCl: Li
Authors: Dischler B.
Published: February 2015

The effects of internal strains on the tunneling levels of KCl : Li are investigated quantitatively. The method, as developed in a preceding paper by TIMME, DISCHLER, and ESTLE1 , is further improved here. A reinterpretation is presented for two experimental results reported in the literature: the resonances in the phonon spectrometer curve and the specific heat (Schottky) anomaly. The agreement with these experiments and also with paraelectric resonance is good, if isotropic strains are assumed with an average energy of 20 GHz, corresponding to a stress of 30 ± 10 kp/cm2 . For the cube edge tunneling interaction a value of 10 GHz is derived.
The Vibrational Spectra of Strontium Chromate (SrCrO4) and Lead Chromate (PbCrO4)
Authors: Scheuermann W. , Ritter G.J.
Published: February 2015

The Raman spectra of the monoclinic compounds strontium Chromate, lead Chromate and of the mineral crocoite (PbCrO4) have been recorded at 300 °K and 77 °K. The spectrum of the orthorhombic modification of lead Chromate has also been recorded. The spectra of the monoclinic and of the orthorhombic PbCrO4 were found to be indistinguishable, whereas the spectra of the isomorphous monoclinic salts SrCrO4 and PbCrO4 are remarkably different. Inversion doubling was observed in SrCrO4 but less distinctly in monocrystalline crocoite.
Gestörte Diffusion von Argon in neutronenbestrahltem Kaliumchlorid
Authors: Müller M. , Felix F.W.
Published: February 2015

The influence of the neutron dose, the neutron spectrum and the sample preparation on Argon diffusion in neutron-irradiated KCl crystals was investigated. No effect of the concentration of the rare gas atoms nore of any other aliovalent atoms produced by nuclear reactions was observed. However radiation damage introduced by the fission neutrons seemed to influence the diffusion behavior. This radiation-damage could be annealed in the presence of thermal or slow epithermal neutrons. Lattice defects which are developed by cleaving of the crystals influenced the gas diffusion too.
Phase Diagram and Transport Properties of Cubic Lithium Sulphate with Small Quantities of Thulium Sulphate and Aluminium Sulphate
Authors: Bengtzelius Ante , Josefson Ann-Mari , Kvist Arnold , Schroeder Kjell
Published: February 2015

The phase diagram and electrical conductivity of cubic lithium sulphate with small quantities of thulium sulphate and aluminium sulphate have been measured. We have also measured the tracer diffusion coefficients of Tm3+ and Al3+ in pure cubic lithium sulphate. The diffusion coefficients of the trivalent ions are much lower than those of the univalent and divalent cations. The results indicate that the trivalent ions are trapped in the lattice.
The Problematic Charge-Transfer Triplet State of Electron-Donor-Acceptor-Complexes
Authors: Briegleb G. , Wolf D.
Published: February 2015

Iwata, Tanaka and Nagakura, and Hayashi, Iwata and Nagakura have observed in ethylether-isopentane solutions (1 : 1) at 77 °K, in the case of the complexes of tetracyanobenzene (TCNB) as the electron acceptor with the electron donors mesitylene (Me), durene (Du) and hexamethyl-benzene (HMB), an unstructured long-lived, long-wave emission band by exciting the complexes in the charge transfer (CT) band. They interpreted the 11, lw band as a CT-phosphorescence of a t t charge transfer triplet excited state | D + A" | . This would be of considerable theoretical interest and significance also for an interpretation of photochemical processes. In the present communication, we report results which lead us to a different interpretation of the 11, lw emission band under discussion. The emission spectra of the complexes of tetracyanobenzene (TCNB) with the electron donors toluene (To), p-xylene (Xy), mesitylene (Me), durene (Du) and hexamethylbenzene (HMB) were studied in glassy solutions in propylether at 100 °K. In the case of TCNB-To, -Xy, -Me and -Du, when the complexes were irradiated in the CT-band so that the complex components were not excited, we observed either the structured phosporescence band of TCNB which originates from a locally excited triplet state of complexed TCNB or, at large donor concentrations, the unstructured long-lived, long-wave emission band within the green spectral range. In the case of TCNB-HMB, only the 11, lw emission may be observed. The 11, lw unstructured emission superimposed on the structured TCNB phosphorescence may also be observed when TCNB, singly soluted in glassy solvents or crystallized, is irradiated in the 31,600 cm -1 (St S0) peak. Obviously, the 11, lw emission band may not be characteristic of the complexes of TCNB. Simultaneously with the 11, lw emission, a new molecular species X can be identified by a new absorption spectrum after irradiating either TCNB itself within the S0 —St 31,600 cm -1 peak or the TCNB-complexes within the CT-absorption band. X is formed by a reaction of the triplet ex-cited TCNB. The excitation in the long-wave absorption peak of X at about 21,000 — 22,000 cm -1 gives rise to an emission with a maximum in the same spectral range as the 11, lw emission band. Accordingly, we interpret the 11, lw emission as a delayed emission of X due to an energy transfer from the triplet excited TCNB.
The Use of the Modified Extended Hiickel Method in Molecular Dynamics
Authors: Yeranos Walter
Published: February 2015

Our previously proposed modification of Hoffmann's extended Hückel method is discussed, and its use in the determination of the dissociation energies of H3M-H type molecules where the H3M moiety is taken as a unit examined. The proposed technique is also used to study the angular dependence of the total potential energy of the previously studied molecules, as a consequence of which it is suggested that the proportionality constants (in this case the Fe 's) are atom-atom parameters, transferable from molecule to molecule. The latter concept is used in the theoretical determination of the geometries and energetics of CH3, SiH3, NH3, PH3,_as well as some of their ionic forms. Finally, as a result of our calculations, we suggest that CH3 is planar with a much flatter potential minimum than CH3.
Zum Vorkommen von Promethium in der Natur
Authors: Meier H. , Zimmerhackl E. , Albrecht W. , Bösche D. , Hecker W. , Menge P. , Unger E. , Zeitler G.
Published: February 2015

After a discussion of former publications on the problem of the existence of promethium in nature, studies o f our own on this problem are reported. In these researches, 200 kg of gadolinite were separated with regard to Pm by using one- and two-stage cation-exchange separations and nitrilotri-aceticacid for elution and Cu2+ as barrier-ion.

The experiments yielded a beta-activity in the mixture-fractions between Sm and Nd. Because of its chemical behaviour and its half-thickness of 4.4 mg/cm2 that corresponds with a β-maximum energy of 230 keV (147Pm: 223 keV), this beta activity could be identified as 147Pm. For the lanthanide oxides of gadolinite a 147Pm content of 7.3 · 10 - 17% could be deduced, which agrees well with the value of 4.5 · 10 - 17% found by Erämetsä in 20 t lanthanide oxides of 6000 t apatite. The possible origin o f the 147Pm-isotope we found in gadolinite is discussed (fallout, actinium anomaly, spontaneous fission of 238U, and others), and the reaction 11,Id 2,6a 14 6Nd (n, y)

is supposed to be the cause of the relatively short-lived isotope. The difference between the neutron flux (36 n/cm2 · min) that was deduced from the saturation activity of 147Pm, and the values of the neutron flux at the earth's surface or crust (0.001-0.24 n/cm2 · min) that up to now have been looked upon as probable by other authors, is also mentioned. Moreover, the question of the possible existence of a long-lived isomer of one of the known Pm-isotopes is rised.
Knight-Shift in kleinen Lithiumtröpfchen
Authors: Engelhardt A. , Sotier S. , Kalus J.
Published: February 2015

In der vorliegenden Arbeit wird untersucht, wie sich die Knight-Shift von kleinen Lithiumtröpfchen in LiF-Kristallen mit der Größe der Tröpfchen verändert; die Tröpfdien wur-den durch Neutronenbestrahlung erzeugt, ihre Größe konnte durch Tempern verändert werden.
On the Field Emission from Ni, Gd, and EuS Evaporated on to Tungsten
Authors: Eckstein W. , Georg K.F. , Heiland W. , Kirschner J. , Müller N.
Published: February 2015

Tungsten tips coated with Ni, Gd and EuS are studied in a field electron microscope. Reproducible patterns are observed. The Gd-patterns show epitaxy with the W-substrate. With tempered tips the work functions are: Ni 5.1 ± 0.3 eV, Gd 3.2 ± 0.3 e V and EuS 3.1 ± 0.3eV.

For the production of polarized electrons by field emission from materials with spin polarized bandstructure 1 - 4 the field emission from Gd, Ni and EuS is of interest.
Exakte Dämpfungskennwerte bei linearen Schwingungen
Authors: Troost A. , Betten J.
Published: February 2015

In der vorliegenden Untersuchung werden Dämpfungskennwerte allgemein formuliert. Als Beispiele sind Kennwerte freier und erzwungener gedämpfter Schwingungen aufgeführt. Die erörterten Abweichungen der meistens benutzten Umrechnungsbeziehungen von den strengen Gleichungen erklären zwanglos einander widersprechende Angaben im Schrifttum.
Stoichiometric FeO as Metastable Intermediate of the Decomposition of Wustite at 225 °C
Authors: Hentschel Bernhard
Published: February 2015

If a wustite sample prepared above 1000 °C is annealed at 225 °C stoichiometric FeO occurs as a metastable decomposition intermediate, as has been demonstrated röntgenographically and by means of the Mössbauer-effect.
Anwendung der Methode der Korrelationsfunktion auf die Berechnung der Richtungsabhängigkeit von Hc2 im kubischen Einkristall
Authors: Harms Klaus-Dieter
Published: February 2015

The upper critical magnetic field for a monocrystalline superconductor with cubic symmetry is calculated using the Method of the Correlation Function. The symmetry of the system leads to an eigenvalue equation which is solved with perturbation-theoretic methods. The upper critical field is calculated for dirty superconductors in the lowest order for which anisotropy is present. For clean superconductors, a higher order is calculated. Some results are critically compared with those in a paper by HOHENBERG and WERTHAMER.
Oberflächenspannung und Thermodynamik des perfekten Gases
Authors: Hilf Eberhard
Published: February 2015

A thermodynamic system of N Fermions or Bosons, bound by an external potential but with almost no additional contribution of the interaction energy between the particles to the binding of the system is called a bound perfect quantum gas. Its single particle energy level density ρ (ε) depends on the properties of the external potential. This is chosen to be zero inside and infinite outside a given arbitrary simple connected closed shape. Within the leptodermous assumption A N1/3 ≫ 1 then ρ (ε) can be written explicitly as a sum of three terms which are proportional to the volume, surface, curvature tension. Its thermodynamics is developed: 1) one thermodynamic variable can be eliminated, reducing the phase space dimensions; 2) the Gibbs - Duhem relation is disfigured only by surface - and curvature terms, stating that the system is still makroscopically homogenious except in the surface area, where e.g. the particle density falls down to zero smoothly; 3) the Landsberg-definition p · V = ⅔ U still holds, confirming that our microscopically defined system is macroscopically a perfect gas in the sense of Landsberg, despite the surface phenomena. In the appendix the advantages of an operatorlike shortwriting of the partial derivative notation are demonstrated.
Ein einfaches statistisches Modell für Transportvorgänge mit beschränkter Ausbreitungsgeschwindigkeit. I
Authors: Keller J.U.
Published: February 2015

A simple statistical model for transport-processes in material systems like heat conduction, diffusion and Rrownian motion is given. The model consists of a one-dimensional unrestricted random walk process. The jump-probabilities of the random-walk-particle generally depend on the history of the particle. The transport equations following from this model describe, contrary to the equations given by Fick, Fourier, Smoluchowski and Fokker-Planck always transport-processes with bounded velocity of propagation.
Ein einfaches statistisches Modell für Transportvorgänge mit beschränkter Ausbreitungsgeschwindigkeit. II
Authors: Keller J.U.
Published: February 2015

In a paper 1 published recently a one-dimensional random walk-model for transport-processes with bounded velocity of propagation like heat conduction, diffusion and Brownian-motion has been given. Now this model is generalized to processes in 3 dimensions. We consider the transport process as a random-walk process in a primitive cubic lattice without boundaries and without external forces. The jump-probabilities of the random-walk-particle generally depend on the history of the particle. The resulting transport-equation contains terms which are due to the structure of the lattice not invariant under rotation. Further on this equation always describes transport-processes with bounded velocity of propagation.
Schwingungsspektren und Kraftkonstanten einiger Tertiärbutylacetylene
Authors: Hüttner W. , Zeil W.
Published: February 2015

A normal co-ordinate analysis of the vibrational spectra of the (CH3)3C-C = C-H, - D, -Cl, -Br and -J compounds has been carried out, and force constants of three slightly different simplified valence force fields have been obtained. Both the iteration procedure described in the preceding paper, and a well-known least-squares technique were used in the computations. The first method proved successful for all species and all force fields. The least-squares method yielded converging results in the case of tertiary butyl acetylene, when the two isotopic frequency sets were refined simultaneously and when a sufficient amount of constraint was introduced into the force field. The force constants belonging to the same force field as obtained by the two independent methods are in good agreement. The valence constants of the acetylenic chain seem to reveal some expected distinctions in the bond properties of the pure acetylene and the halogenated compounds.
Messungen der radialen Verteilung der elektrischen Feldstärke im Wasserstofflichtbogen mit axialem Magnetfeld
Authors: Schwenn R.
Published: February 2015

In a stationary hydrogen arc with axial magnetic field the radial distribution of the axial electric field Ez was measured by shooting a double potential probe across the arc. It was found that Ez strongly decreases outside the magnetic flux tube defined by the cathode radius and tends to zero. The measured distribution of Ez agrees qualitatively with computations allowing for the observed rotation profile. In a very fast rotating arc with a hollow anode Ez was found to vanish not only outwards, but also towards the axis, as predicted by the theory.
Radiales Druckprofil in einem magnetoplasmadynamischen Wasserstoff-Lichtbogen
Authors: Bohn W. L. , Mccann T. E.
Published: February 2015

Within the framework of the five-moments approximation the radial pressure profile of an MPD-arc is calculated as a function of the ambient pressure and the superimposed magnetic field. In addition to the well known pressure increase due to ambipolar diffusion, the typical axi-symmetric MPD geometry provides further pressure increase or decrease by the interaction of current density (Hall-effect) or mass flow with the magnetic field. Characteristic pressure profiles for assumed current and flow fields and for various superimposed magnetic field strengths are shown in numerous diagrams and are discussed by use of the generalized Ohm's law. A significant pressure decrease due [to mass entrainment becomes evident. Deviations from LTE are considered in the frozen flow approximation. The theoretically predicted pressure decrease in the axial region of the plasma flow of an MPD-arc subjected to mass entrainment agrees qualitatively with experimental results.
Bestimmung der Ionendichte aus der Stark- Verbreiterung der Hβ-Linie bei elektrischen Entladungen in H2-cluster-Strahlen
Authors: Klingelhöfer R. , Moser H. , Röhl H.
Published: February 2015

A transient plasma column is produced by discharging a 0.1 μF-capacitor at 20 kV along a beam of hydrogen clusters. The time dependance of the ion density is obtained from Stark broadening measurements of Hβ (4861 Å). A maximum density of 6.6 × 1016 ions/cm3 is achieved, the initial density of the neutrals in the beam being 8.5 × 1017 H2 molecules/cm3. The background number density in the surrounding vacuum amounts to about 7 × 1010 molecules/cm3.
Atom Transport Under Varying Pressure * *
Authors: lazarus D , Yoon D. N. , Jeffery R. N.
Published: February 2015

Study of the effect of hydrostatic pressure on the rate of diffusion-limited processes gives in­ formation regarding the intrinsic volume changes associated with formation and motion of defects. While there are basic problems associated with interpretation of the motional volume, such effects may be measured directly in some cases and subtracted to give unambiguous results for the defect formation volume. Experimentally, precise measurement of specimen temperature within a high-pressure environment poses the most severe practical constraint. Results are given for measurements to pressures of 7 kilobars of ionic conductivity in a series of pure and doped alkali halides: NaCl, KCl, NaBr, and KBr, all of which are predominantly cationic vacancy conductors. The activation volumes are found to be pressure dependent in the intrinsic regions. In all cases the Schottky pair vacancy formation volume is found to be larger than the molar volume, the ratio being largest for NaCl and smallest for KBr. Results are also given for the total activation volume for diffusion of Ti44 in beta-Ti, a case of "anomalous" bulk diffusion. The tracer penetration plots do not follow a perfect gaussian profile. However, if the penetration plots are fit to a single gaussian, the activation volume derived is consistent with that expected for a vacancy mechansm in bcc metals
Elektronenstoßspektrometrische Bestimmung von Besetzungsdichten in einem Heliumplasma / Determination of Population Densities in a Helium Plasma by Electron Impact Spectroscopy
Authors: Boersch H. , Geiger J. , Topschowsky M.
Published: February 2015

Determination The energy spectrum of a narrow electron beam (primary energy 25 keV, energetic width 0,08 eV) has been measured after having passed a low voltage helium discharge constricted by a metal capillary. Besides the resonance series, which is characteristic for the helium atoms in the ground state, electron energy losses are found due to transitions from excited states. In addition superelastic collisions occur which are caused by de-excitation processes. Population densities of the atoms in excited states are derived from the intensities in the electron energy spectrum using the wellknown transition probabilities. The result is compared with population densities obtained by means of Saha's equation as well as with those in both cases.
Lassen sich Quantenzustände als Ensembles streufreier Zustände darstellen? II / Can quantum-states be considered as ensembles of dispersionfree states? II
Authors: Ochs W .
Published: February 2015

In part I of this paper we constructed a model representing quantum states by ensembles of dispersionsfree states. In part II we study further properties of this model and analyse their logical relations. It is also shown that the main results do not depend on the assumption that each self-adjoint operator corresponds to an observable.
Ein Mikrowellen-Mikrowellen-Doppelresonanz-Spektrograph mit gekreuzten Feldern
Authors: Rudolph H. D. , Dreizler H. , Andresen U.
Published: February 2015

Es wird ein Mikrowellen-Mikrowellen-Doppelresonanz-Spektrograph mit gekreuzten Feldern beschrieben. Dieser Spektrograph hat den Vorteil, daß vom experimentellen Aufbau her die Pump-und Signalfrequenz unabhängig voneinander sind. Die theoretische Linienform für gekreuzte Felder wird abgeleitet und den entsprechenden Messungen gegenübergestellt.
Investigations on Diffuse Reflectance Spectra of V2O5 Powder
Authors: Karvaly Bela , Hevesi Imre
Published: February 2015

On the base of Schuster-Kubelka-Munk's theory, quantitative relations between the bulk absorp­ tion and diffuse reflectance spectra of undiluted and diluted semiconductor powder samples are established in the region of the long-wave tail of the absorption edge. Investigations in the long­ wave region of the diffuse reflectance spectra of V2O5, based on these relations, led to the result that in contradiction with earlier observations on single crystals7, 22, 27, allowed direct optical transitions between valence band and conduction band do not seem to be excluded. Quantitative optical activation energies are obtained from diffuse reflectance spectra.
Electronic Spectra of Antimony Monobromide
Authors: Avasthi M.N.
Published: February 2015

Antimony monobromide was excited with the help of a microwave oscillator of 2450 mega cycles. Three new band systems in emission have been observed in the regions 2950 -3020 Å, 3050 - 3340 Å and 4905 -5340 Å; of which the first two have been discussed in this paper. All bands are degraded towards the red; they have been classified and attributed to the new molecule SbBr. Isotopic effects due to Br79 and Br81 have been observed in one of the systems.
Zur Selbststabilisierung der Gegenstromelektrolyse bei Verwendung starker Säuren als Gegenstromelektrolyten
Authors: Bilal B.A. , Mühlig B. , Schwarz B.
Published: February 2015

Es wurden Bedingungen ermittelt, bei denen eine Selbststabilisierung der Salzverteilung bei Verwendung starker Säuren als Gegenstromelektrolyten möglich ist. Die Grenzen, innerhalb derer sich die Selbststabilisierung vollzieht, wurden diskutiert.
The Isotope Effect of Electromigration in Some Solid Alkali Halides
Authors: Morimoto Takeshi , Okada Isao , Saito Nobufusa
Published: February 2015

The isotope effect of electromigration in some solid alkali halides was determined in their intrinsic ionic conductivity region. The external cationic mass effect (i. e., relative difference in cationic mobility/relative difference in mass) of lithium fluoride, chloride, bromide and iodide and potassium chloride was -0.243, -0.207, -0.195, -0.190 and -0.254, respectively, at 750, 540, 470, 370 and 600 °C, respectively. No difference of the mass effect was found between polycrystalline and single crystal potassium chloride. When the available data for the mass effect of the solid salts are plotted against the activation energy for electric conductance, there is a tendency for the mass effect to increase as the activation energy increases.
Einfluß der Rotation auf die Lebensdauer prädissoziierender Moleküle
Authors: Comes F. J. , Schumpe G.
Published: February 2015

The D 1∏u - X1∑g
+system of H2 and D2 shows strong predissociation. High resolution m easurements on the line widths of isolated absorption lines have been carried out, showing the influence of rotation on the predissociation probability of the corresponding rotational states. Their lifetime decreases with increasing rotation of the molecule and with decreasing mass due to the coupling of electronic and rotational motion. Both results are in excellent agreement with theoretical predictions given by Kronig.

The shape of the absorption lines broadened by predissociation was found to be typically asymmetric. They are of the Beutler type, well known form the autoionisation of the rare gases.
Infrarot-und Raman-Spektren von TiCl4/TiBr4-Gemischen
Authors: Bürger Hans , Kluess Carsten , Wiegel Klaus , Höfler Friedrich
Published: February 2015

Die Raman- und Fern-IR-Spektren der Verbindungen TiClnBr4-n (n = 0 - 4) wurden aufgenommen und durch Kraftfelder wiedergegeben, die sich von TiCl4 und TiBr4 herleiten. Die Ergebnisse erweisen eindeutig die Anwesenheit aller Zwischenglieder in statistischer Verteilung, sichern die lückenlose Zuordnung der gemessenen Spektren und bestätigen die Übertragbarkeit von Kraftkonstanten für eine Gruppe von Übergangsmetall-Verbindungen.
A Simple Algebraic Calculation of the Resolvent in the Vθ-Sector of the Lee Model
Authors: Dewitz H. v. , Helmers K.
Published: February 2015

It is shown that the resolvent in the Vθ-sector of the Lee model may be expressed by simple algebraic operations in terms of known matrix elements between states of the V-sector.
Level-Crossing-Untersuchung des 6p 2P3/2-Terms im Au I-Spektrum durch Resonanz­streuung von Licht im elektrischen und magnetischen Feld zur Bestimmung der Hyperfeinstrukturtermordnung / Stark Effect Investigation of the 6p 2P3/2-State in Au I -Spectrum in Order to Determine the Signs of the Hyperfine Structure Constants
Authors: Einfeld D. , Ney J. , Wilken J.
Published: February 2015

Level crossing technique, applying parallel electric and magnetic fields, has been used to determine the signs of the hyperfine structure constants A and B as well as the magnitude of the Stark-constant β . From the Stark-shift of the signal at 45 Oe in the wing of the Hanle-effect and of the level-crossing near 140 Oe to higher magnetic field strengths the ratios A/β > 0 and B/ß > 0 could be determined. An estimation of β by calculating the electric dipole matrix elements with Coulomb approximation yields a positive sign. Both signals and their shift with electric field then can be explained with the following results:

A = + 14.0 (5) Mc/sec; 5=+327.6 (1.6) Mc/sec and β= +5.7(3) (kc/sec) (kV/cm)-2.
Level Structure of 143Pr from γ Decay
Authors: Bashandy E.
Published: February 2015

The γ decay of 143Ce has been investigated using both a Ge(Li) γ ray and a high resolution iron free double focusing β-ray spectrometer. In addition to γ rays previously reported, more γ rays could be observed. Internal conversion coefficients and multipolarities of γ transitions were determined. Ten excited nuclear energy states have been established in 143Pr at 57, 341, 491, 722, 939, 1045, 1061, 1161, 1382 and 1452 keV. Possible spin values have been assigned to all these states on the basis of conversion coefficients of γ rays. The level structure of 143Pr is discussed in terms of existing nuclear models.
Low Temperature Heat Capacities of Transition Metal Borides
Authors: Hanson B. D. , Mahnig M . , Toth Louis E.
Published: February 2015

Low temperature heat capacities from 1.5 to 15 K have been measured for a number of transition metal borides with the compositions Me2B, MeB and MeB2 , and their solid solutions. The measurements show that the borides are characterized by a narrow d-band with a relatively large density of electron states. The variation of γ with position of the transition metal in the Periodic Table for the borides is considerably different from that of the transition metals and solid solutions. This result suggests considerable differences in the shapes of the respective band struc­tures. There is evidence for an electron transfer from the boron atoms to the d-bands of the transition metal.
Vibration Spectra and Debye Temperatures of Some Transition Metals
Authors: Sharma P. K. , Semwal B. S. , Mehrotra K. N.
Published: February 2015

The lattice vibration spectra and the associated constant volume specific heats of the transition metals niobium, tantalum, chromium, and palladium have been determined by using Sharma and Joshi's three-force constant model which includes the effect of electrons on lattice vibrations in metals. The calculated values of the specific heats and the equivalent Debye temperatures are com­pared with available calorimetric data. The frequency versus wave vector dispersion relations along the three major symmetry directions of chromium and palladium are determined and compared with curves deduced from recent neutron scattering experiments. Reasonably satisfactory agreement between theory and experiment is obtained.
Interdiffusion Studies in Molten Alkali Nitrates
Authors: Arvidsson Torkel E. G. , Afsenius Sven-Åke , Gustafsson Silas E.
Published: February 2015

Interdiffusion of anions in fused alkali nitrates has been studied with a plane source diffusion technique; the concentration gradients in the diffusion cell being measured with a wave-front-shearing interferometer. By choosing the same cations in the experiments the diffusional mixing of different anions at low concentrations into three alkali nitrates has been studied. The diffusion coefficients of F- and Br- in LiNO3; F-, Br-, I-, CO3
2-, and SO4
2- in NaNO3; and I- and CO3
2- in RbNO3 were obtained over a temperature range of some 100 °C above the melting point of the different solvents.
Verzögerte Fluoreszenz und Phosphoreszenz in reinen Naphthalin-Kristallen
Authors: Benz K. W. , Port H. , Wolf H. C.
Published: February 2015

In extremely purified naphthalene crystals triplet exciton lifetimes up to 500 msec at room temperature were measured. The triplet annihilation coefficient is measured from an analysis of the light intensity dependence of delayed fluorescence as γ = 3.5 · IO-12 cm3 sec-1 at 300 °K and at 135 °K. The quantum yields in the weak excitation limit at room temperature are ηDF = (3 ± 0.6) · 10-3 for delayed fluorescence and ηp = (1.2 ± 0.3) • 1O-3 for prompt phosphorescence, both after triplet excitation. The phosphorescence spectra of naphthalene and perdeuteronaphthalene crystals are analyzed between 300 and 50 °K. The line width decreases from 270 cm-1 at 300 °K down to 42 cm-1 at 60 °K.
Zum Einfluß elektrischer Felder auf den Szintillationsprozeß in CsJ/Tl
Authors: Scharmann A. , Traunfelder H.
Published: February 2015

The luminescence yield of CsJ/Tl-crystals under the influence of electric fields is investigated. At excitation with ionizing radiation the intensity depends on the incident particles and their differential energy loss. The Tl-centres are not influenced by the electric field during UV-irradiation, while at β-and γ-excitation a decrease of luminescence intensity is observed, depending on the Tl-concentration. When a-irradiated, the intensity of the Tl-band remains unaffected. The possible mechanisms of the energy transfer are discussed in terms of the excitation density and Tl-concen­tration.
Random Walk Theory of Elastic and Inelastic Time Dependent Collisional Processes in an Electric Field
Authors: Englert Gerald W.
Published: February 2015

Random walk theory is applied to the motion of electrons in the early stage of breakdown of helium in an electric field. Details of inelastic and elastic interactions are based on integral and differential cross section data. The concept of mean free time is extended to include the effect of acceleration between collisions due to the electric field.

The relaxation of electron energy distributions from initial delta functions to steady terminal distriubtions is studied. Relaxation time determined by the random walk is shown to be closely approximated by a simple energy exchange relation between electrons and the electric field.

Drift velocity and the first Townsend ionization coefficient are determined and compared with experimental results. Various simplifying assumptions which have been used in analytical studies are appraised by use of the random walk procedure.