bluuebunny/crossref_metadata_2025 huggingface dataset:
Schallgeschwindigkeitsmessung in Bi-Cu Schmelzen zur Bestimmung der Kompressibilität und der partiellen Strukturfaktoren / Sound Velocity, Compressibility, und Partial Structure Factors (q = 0) in Bi-Cu Melts
Authors: Ebert Helmut , Höhler Jochen , Steeb Siegfried
Published: February 2015

The adiabatic velocity of ultrasound in molten Bi-Cu alloys was measured at various concentrations and temperatures. For the alloys with concentrations between 40 and 80 a/0 Cu the μ(T)- curves consist of two linear regions with a transition region. Within the concentration range mentioned ⊿u/⊿T and the compressibility show respectively positive and negative deviations from linearity. The deviations can be detected at temperatures up to 1200 C. The total structure factors I(O) for Bi and Cu as well as the partial structure factors aij(O) were obtained. aCuCu(O) shows rather high values, indicating the existence of inhomogeneities containing mainly Cu-atoms. The slope of ⊿Nj' [which is a linear combination of the aij (O)] versus concentration is negative. From this fact follows that segregation must exist in these melts. This also follows from the rather large density fluctuations given by the partial factors SCC(O) obtained in this work.
Enrichment of Radiocarbon for Dating Samples up to 75,000 Years
Authors: Grootes P. M. , Mook W. G. , Vogel J. C. , Vries A. E. de , Haring A. , Kistemaker J.
Published: February 2015

The range of the radiocarbon dating method can be extended by about 20,000 years by means of thermal diffusion isotopic enrichment. A description of the Clusius-Dickel type enrichment columns and their operation is given. Prior to enrichment the carbonaceous sample material is combusted to CO2 and then reduced to CO. The enriched sample is re-oxidized to CO2 . The combustion-, reduction-and oxidation-apparatus and their operation are described.

The performance of the thermal diffusion columns has been tested and an empirical, volume independent relation between the isotope separation factors of 14C 16O and all molecules with mass 〈30〉 is given

q14 - 1 = (1.13 ± 0.05) (q30 - 1) + (0.035 ± 0.005) (q30 - 1)2 .

The influence of contaminations on the reability of 14C dates obtained with this method is discussed. Laboratory contaminations can be kept below the detection limit as is shown by the preparation of two anthracite samples. Still there may be some influence on dates obtained for very old samples. As far as laboratory contaminations are concerned, dates up to 75,000 years can be obtained.
EPR of Fe3+ in Low Quartz Isomorphs A(III)B(V)O4
Authors: Krauß Ulrich , Lehmann Gerhard
Published: February 2015

Electron spin resonance spectra of Fe3+ in hydrothermally grown single crystals of AlPO4 , GaPO4, AlASO4 and GaAsO4 were measured at X-band and analyzed using a Spin-Hamiltonian for rhombic symmetry. The zero field splitting was found to be between about one and two times the microwave frequency, increasing regularly from AlPO4 to GaAsO4. This increase is largely due to an increase in the axial parameter D whereas the second order rhombic parameter E is practically constant. The fourth order parameter a increases exponentially with the lattice parameter ratio c0/a0 . The variation of D indicates a site distortion for GaPO4 about twice as large as in AlPO4 . For the arsenates, influences of increased covalency are apparent in addition to site distortions of comparable size. Halfwidths in the range of 18 Gauss for the phosphates and 38 Gauss for the arsenates indicate hyperfine interactions with 31P and 75As, and estimates of 0.5 and 1% spin density resp. at these nuclei are obtained, again showing increased covalency for the arsenate compounds.
A Method for Measuring Interdiffusion Coefficients in Liquids by Wave-front-shearing Interferometry
Authors: Gustafsson Silas E. , Karawacki Ernest , Okada Isao
Published: February 2015

A new method for measuring interdiffusion coefficients in transparent liquids is presented. By using a diffusion vessel made of fused quartz with optically flat surfaces perpendicular to the optic axis it is possible to follow the complete concentration distribution with a wave-front-shearing interferometer during the diffusion process.
Hydrogen Isotope Fractionation between HCl2
- Ion and HCl
Authors: Szydłowski J.
Published: February 2015

Hydrogen isotope fractionation between hydrogen dichloride ion in the condensed phase and gaseous hydrogen chloride has been studied both theoretically and experimentally. Quite good agreement between the experimental tritium fractionation factor and that theoretically calculated for two sets of vibrational data was found. Theoretical calculations of the fractionation factors of both deuterium and tritium over the large temperature range of 100-2000 K revealed some anomalies (minima and crossover points) in their temperature dependences. The relative tritium-deuterium isotope effect has also been discussed within the framework of the presently accepted statistical-thermodynamic theory in the harmonic approximation and recent works by Stern et al.
Über die Temperaturabhängigkeit der Dichte von dünnen Kupferaufdampfschichten / On the Temperature Dependence of the Density of thin Vacuum Deposited Copper Films
Authors: Wagendristel A. , Söllner E.
Published: February 2015

A short literature survey on the subject is given with special emphasis on discrepancies and contradictional interpretations of results. Our own experiments on thin copper films evaporated onto glass substrates at different condensation temperatures are reported. Density values were calculated from the film thickness, which was measured by Kiessig's method and from the deposited mass determined by atomic absorption spectrometry as well as gravimetric measurements. The density defect decreases with increasing film thickness, as already established, and also with temperature.

From these results together with those obtained from films which were deposited during a rapid temperature rise from the low substrate temperature to room temperature we conclude that the density defect is localized at the substrate - film boundary.
Densities and Excess Volumes of Fused Halides
Authors: Brookes H. C. , Paul R. L.
Published: February 2015

Densities of molten AgBr-AX (A = Li, Na, K, Rb, Cs; X = Br or Cl), AgBr-AgCl, KBr-NaBr, KBr-CsBr, KCl-KBr, and KCl-CsBr mixtures have been measured at 0.5 mole fraction using the method of Archimedean displacement. The excess volumes of mixing are all positive, except for the AgBr-LiBr system. Attempts to relate the excess volumes of the binary AgBr-ABr systems to the second order conformal solution theory of Reiss, Katz, and Kleppa are unsuccessful, since V E is large even when the diameter difference parameter, δ12, is close to zero. However, the excess volumes of the reciprocal AgBr-ACl systems at 0.5 mole fraction are found, within experimental error, to have a linear dependence on δ12. The positive deviations from conformal solution theory which occur for the alkali halide mixtures have been interpreted in terms of non-Coulombic polarisation and van der Waals interactions.
Magnetowiderstand und Bandverschiebungen an halbleitenden Wismut-Antimon-Legierungen unter hohem hydrostatischem Druck / Magnetoresistance and Band Shifts in Semiconducting Bismuth-Antimony Alloys under High Hydrostatic Pressure
Authors: Schneider Detlef , Kruse Rolf , Neubauer Helmut
Published: February 2015

Magnetoresistance The magnetoresistance of semiconducting Bi100-xSbx single crystals (x = 5.5 and 6.3 at % Sb) at T = 297, 77 and 63 K was measured in magnetic fields up to B = 15 T. In this region, the dependence of the magnetoresistance on the magnetic field strength exhibits a negative slope, which is characteristic for semiconductor-semimetal or semiconductor-quasimetal transitions, as previously observed by other authors in Bi-Sb alloys in the liquide He-temperature range.

The influence of hydrostatic pressure (p ≦ 15 kbar) on the extrema of magnetoresistance oscillations at T = 77 and 63 K arising from the Shubnikov-de Haas effect has been examined. The results confirm the concept of approaching and mutually repelling L-point conductivity and valence bands. For the samples investigated, the energy gaps [Eg(x = 5.5) =6.94 meV and Eg(x = 6.3) = 7.64 meV] show pressure dependences of dE/dp= -1.16 · 10-6 eV/bar at 77 K and -1.39 · 10 -6 eV/bar at 63 K, respectively.

Preparation of the samples, their characterization in terms of chemical microanalysis and dislocation densities as well as the method of applying high hydrostatic pressure are described in detail.
Magnetic-field Induced Change of the Viscosity of Diamagnetic Gases with Anisotropic Magnetic Susceptibility
Authors: Hess S.
Published: February 2015

The influence of a high magnetic field on the viscosity of diamagnetic gases of linear, symmetric and asymmetric top molecules is studied within the frame-work of the kinetic theory based on the Waldmann-Snider equation. The quadratic Zeeman effect associated with the anisotropic magnetic susceptibility is taken into account in addition to the usual linear Zeeman splitting.
Ground State Rotational Bands in 16O, 40Ca and 208Pb?
Authors: Lezuo K.
Published: February 2015

It is pointed out that a considerable amount of evidence exists to support the concept of a ground state rotational band based on tetrahedral deformation for 16O, 40Ca and 208Pb. The possible meaning of this interpretation as well as other well-known alternatives are discussed.
Gamma-Ray Induced Luminescence of Silica Gel
Authors: Breitkreutz K. , Kirmaier P. , Rabe J. G.
Published: February 2015

Luminescence observed on adsorption of gases and vapours (RSL) on silica gel previously ex-posed to y-rays has been investigated. The dependence of RSL intensity on absorbed radiation dose and degassing temperature of the gel prior to irradiation parallels the dependence of radio-thermoluminescence (RTL) intensity: A limiting value is reached around 1 Mrad and the intensity increases steeply on raising the degassing temperature. The RSL intensity is largest on adsorption of H2 and decreases in the order H2; O2; N2O; N2; He. The stronger the RSL effect, the more is the subsequent measured RTL reduced. The RSL emission spectrum has a maximum at 450 nm and is identical with the spectrum of RTL. In some cases bands at longer wavelengths have been observed. The RSL decays with hyperbolic kinetics which may be related to the logarithmic rate of adsorption as given by the Elovich equation. The results are discussed in terms of detrapping of charges, in this case stimulated by adsorption, and the recombination of carriers leading to excitation of luminescent centers as in RTL. The emission bands at longer wavelengths are thought to involve electron transfer from interacting molecules neutralizing holes trapped in the solid.
Bestimmung kernresonanzspektroskopischer Parameter durch Lorentz-Kurven-Form-Analyse: I [C6F5Si(CH3)2]2 / Determination of NMR Parameters by Lorentzian-Line-Shape-Analysis I: [C6F5Si(CH3)2]2
Authors: Hägele Gerhard , Lueg Volker
Published: February 2015

The set-up of digital-out-put for HR-CW-NMR-spectrometers and computer-programs suitable for Lorentzian-line-shape-analysis is reported. The values for 5JHF AND 6JHF IN [C6F5Si(CH3)2]2 are determined.
Absolutmessung der Leistungseinkopplung in ein Deuterium-Plasma bei der unteren Hybrid-Resonanz / Absolute Measurement of Power Transfer to a Deuterium Plasma Near the Lower Hybrid Resonance
Authors: Lammers B. , Oberlack U. , Schlüter H.
Published: February 2015

Absolute Measurement of Power Transfer to a Deuterium Plasma Near the Lower Hybrid Resonance The power transfer to a deuterium plasma generated by a high frequency discharge near the lower hybrid resonance is investigated in the range of several hundred watts. The results are compared with linear theories. Reasonable agreement is found between measurements and the linear theory of a bounded plasma as far as the wings of the resonance are concerned. But the dominant radial modes predicted by theory are not observed. Introduction of an empirical effective collision frequency ν* = 0.2 ωpe, however, results in good agreement between measurements and theory in the domain of these radial modes.
Spektroskopische Untersuchungen des Plasmas einer Glimmentladungslampe / Spectroscopic Investigations of the Plasma of a Glow Discharge Lamp
Authors: Büger P. A.
Published: February 2015

The electron concentration, the excitation temperatures (from Ar-I-, Ar-II-and Cu-lines) and the rotation-and vibration temperatures (from N2-and N2
+ -bands) have been measured in a glow discharge lamp. Spectral lines of neutral molecules indicate temperatures in the range of 3000 K. Using ion lines as indicator it could be shown that Texc > Tvib > Trot (30 000; 9300; 1190 K). The former are hardly affected by discharge parameters, the latter ones are strongly affected. At the edge of the glow the temperature is distinctly lower. The electron concentration is approx. 10 14 cm-3. The results are discussed.
EPR of Radiation Damage Centers in NaNO3, Sr(NO3)2, BaS, and MgC2O4·2H2O
Authors: Köksal F. , Yüksel H.
Published: February 2015

NaNO3, Sr(NO3)2, BaS, and MgC2O4·2 H2O powders have been gamma-irradiated at room temperature and their electron spin resonance spectra examined for paramagnetic species. The species identified were NO3 and NO2 radicals in the nitrates, SO2
- and S in BaS, and H2C2O4
- in magnesium oxalate. Theoretical predictions agree with these assignments.
Molecular Nature of the g Anomalies in Bis(diselenocarbamate)copper(II) Complexes
Authors: Buluggiu E. , Dascola G. , Gruppo D. C. Giori
Published: February 2015

It is pointed out that from the measured principal g values in single crystals of bis (diethyldiselenocarbamate) copper (II) it is possible to deduce the g values for the single molecular unit. By a reasonable choice of its principal directions it turns out that the g tensor is axial along the bisecting line of the major angle between the Cu-Se bonds, with g∥ ∼ 2.05 and g⊥ ∼ 2.01. These values seem to confirm the presence, also in the pure Cu crystals, of the main g anomaly, recently observed in the Cu : Ni diluted crystals. Therefore, one can infer that the anomaly is essentially due to the nature of the Cu-Se bonds and not to distortions produced by the Ni diamagnetic matrix.
Kinetics and Mechanism of Solid State Reactions in the Agl-TlI System
Authors: Flor Giorgio , Massarotti Vincenzo , Riccardi Riccardo
Published: February 2015

The kinetics of the solid state reactions

AgI + TiI → AgTlI2 (I)

Agl + AgTl2I3 → 2 AgTlI2 (II)

AgTlI2 + Til → AgTl2I3 (III)

are investigated with reactant pellets by the contact method.

With the aid of inert marker experiments and transport number determinations it was possible to state that the governing mechanism is the cation counter-diffusion in all cases and that the rate determining step is the diffusion of Tl+.

The experimental reaction rate constants agree reasonably with those calculated on the basis of the Wagner's thermodynamic theory.
Gitterschwingungsspektren. XIV NiAs-und Fe3Se4 -Struktur / Lattice Vibration Spectra. XIV. NiAs and Fe3Se4 Structure
Authors: Lutz H. D. , Haeuseler H. , Willich P.
Published: February 2015

The results of a factor group analysis, the symmetry coordinates and vibrational modes of the lattice vibrations of compounds crystallizing in NiAs structure respectively NiAs defect structure (Fe3Se4 type) are presented. A normal coordinate treatment of the NiAs structure is performed using the GF-matrix-method assuming a valence force field with 3 force constants.
Q-values for (d,p) and (d,t) Reactions on Even-A Tin Isotopes
Authors: Bechara M. J. , Dietzsch O.
Published: February 2015

Relative Q-values for (d, p) and (d, t) reactions on all even-A tin isotopes have been determined by simultaneous detection in nuclear emulsions placed in the focal plane of a magnetic spectrograph of the particle groups corresponding to the ground state transitions. The results when combined to other input data for the atomic mass tables provide more accurate mass excesses for nuclides in this mass region.
Decoration of Cleavage Steps on CaF2 Crystal Surfaces
Authors: Büger P. A. , Reichelt K.
Published: February 2015

Cleaved crystal surfaces of CaF2 were decorated by means of gold deposited on the crystal surface by vacuum evaporation. The influence of the substrate temperature on the decoration behaviour was studied.
Folgerungen aus der fundamentalen Ungleichung / Consequences of the Fundamental Inequality
Authors: Kern W.
Published: February 2015

Consequences of the Fundamental Inequality An important feature of the entropyfree thermodynamics of processes is the well-known fundamental inequality. In the case of simple thermodynamic materials and on certain analytical assump-tions we deduce from it the representation of the constitutive equations for processes which remain sufficiently close to an equilibrium state.

We further consider materials which are of the differential type and of complexity one. It is shown that for such materials the equilibrium entropy, which can be used as a well-defined auxiliary function during a process, can be regarded as a possible entropy in non-equilibrium. This theorem is only based on the validity of the fundamental inequality. It is therefore an improvement of the theorem of Keller and König.
The Two Center Oscillator Potential with Finite Depth
Authors: Ong Piet-Tjing , Scheid Werner
Published: February 2015

It is suggested to diagonalize the Hamilton operator of a two-or more center shell model in terms of oscillator functions concentrated around the individual centers. The method is applied to the case of a two center oscillator with finite depth.
Dynamic Screening Model of the Electric Microfield Distribution
Authors: Ecker Günter H. , Schumacher Alex
Published: February 2015

Starting from the linearized Klimontovich equations and the pair approximation we study the probability distribution of the electric microfield. We deduce the separation of the total microfield distribution into a high and a low frequency component. We further prove that each of these com-ponents can be calculated from a model of uncorrelated, dynamically screened particles. The low frequency component, which is of prominent interest for applications, is evaluated. The results show devations from all earlier theories.
Frequency Dependence of Collisional Depolarization of Resonance Radiation
Authors: Schuller Frédéric , Behmenburg Wolfgang
Published: February 2015

We have studied collisional depolarization of resonance radiation with special attention given to the line wings. It is shown that in the one particle quasistatic limit the fluorescence radiation is completely depolarized, independently of frequency and perturber density. By comparison with the integrated polarization degree it is concluded, that the polarization state of the radiation must exhibit a frequency dependence.
Messung von Anregungstemperaturen in einer Glimmentladungslampe / Measurement of Excitation Temperatures in a Glow Discharge Lamp
Authors: Büger P. A. , Alfy S. El
Published: February 2015

Measurement of Excitation Temperatures in a Glow Discharge Lamp Excitation temperatures indicated from Fe-I and Fe-II spectral lines have been measured in a glow discharge lamp using relative intensities of 49 selected spectral lines. Different excitation temperatures resulted: the temperatures were in the range of 3000 -5000 K (Fe-I lines) and 20000 K (Fe-II lines). The former are hardly, the latter ones strongly affected by discharge parameters. The results are discussed.
Oxidation von Nickelschichten untersucht mittels Elektronenbeugung / Oxydation of Thin Ni-foils Investigated by Electron Diffraction
Authors: Drautz Siegfried , Steeb Siegfried
Published: February 2015

Recrystallized nickel foils were treated by oxygen (2·10-4 Torr up to 10-3 Torr) at temperatures up to 550 °C within an electron diffraction set. The treatment was done isothermal and isobaric during few minutes up to several hours. The change in structure was observed. Additional reflexions occured and could be interpreted as due to double reflexion. Under the conditions mentioned above nickel changed into nickel monoxide directly, i. e. without formation of sub-oxides or other intermediate phases. This is in accordance with the fact that up to now no sub-oxides to the transition metals of group VIII a have been found.
Bestimmung elastischer Konstanten von MBBA und EBBA mit der elektrischen Leitfähigkeitsmethode / Determination of the Elastic Constants of MBBA and EBBA by Electric Conductivity Measurements
Authors: Greulich M. , Heppke G. , Schneider F.
Published: February 2015

Several methods of studying the elastic behaviour of nematic liquid crystals by means of measuring the electric conductivity are discussed. The temperature dependence of the ratio of the splay and bend elastic constants to the anisotropy of the magnetic susceptibility is determined for N-(p-methoxybenzylidene) -p-n-butylaniline (MBBA), N-(p-ethoxybenzylidene) -p-n-butylaniline (EBBA) and mixtures of both.
Dispersion of Localized Mode Polaritons in K3Cu(CN)4
Authors: Nitsch Wilhelm
Published: February 2015

The dispersion of polaritons of symmetry A1 and E is investigated in the region of four isotopic vibrations originating from C13- and N15 -atoms in their natural abundances. The measured dispersion curves are explained in terms of a theory for localized mode polaritons (LMP) developed by Ohtaka. The dispersion relation is generalized for a polyatomic crystal and applied to K3Cu(CN)4. The comparison of experimental data with calculated dispersion curves shows a quite satisfying agreement for a certain value of the coupling constant which is approximately the same for E-type and A1-type polaritons.
Microwave Spectrum and Quadrupole Coupling Constants of 2-Bromothiophene
Authors: Mjöberg P. J. , Ralowski W. M. , Ljunggren S. O.
Published: February 2015

The microwave spectra of the two 79Br and 81Br isotopic species of 2-bromothiophene have been measured in the region 18000-40000 MHz.

For both isotopic species, the rotational constants of the ground state and one vibrationally excited state were determined, as well as the centrifugal distortion coefficients of the ground state. The ground state rotational constants in MHz are as follows:

C4H3
32S79Br C4H3
32S81Br

A = 5403.432 ±0.111 5403.563 ±0.095,

B = 1139.0689±0.0010 1126.5173±0.0011

C = 940.5142±0.0018 931.9315±0.0009.

In order to perform a second-order perturbation treatment of the quadrupole interaction, the matrix elements of products of direction cosines in terms of the symmetric top wave functions have been derived. By the first-and second-order perturbation analysis of the hyperfine splittings of the rotational lines, the nuclear quadrupole coupling constants have been determined. The values in MHz are

Xaa = 592.7 ±1.5 493.7 ±1.5,

Xbb = -295.3 ±0.6 -245.6 ±0.7,

Xcc = -297.4 ±1.6 -248.1 ±1.6,

Xab = 80 ±9 64±8 ,

in the principal axes system of the molecule.
Notizen: The Heats of Adsorption of the Trichloroethanes on Porous Alumina
Authors: Tribbeck T. D.
Published: February 2015

The trichloroethanes undergo rapid dehydrochlorination in the presence of porous transitional aluminas, at temperatures as low as 80 °C. Attempts to measure their heats of adsorption on these solids above 80 °C are therefore unsuccessful. Silica gel is an inactive dehydrochlorination catalyst, and the heat of adsorption of 1,1,2-trichloroethane measured for this material is reported.
On Excess Electron Mobility in Liquid and Glassy 3-Methylpentane
Authors: Kalinowski I. , Rabe J. G. , Schmidt W. F.
Published: February 2015

The temperature dependence of the excess electron mobility in liquid 3-methylpentane was measured from 258 K to 371 K. The results are compared with the data obtained by Maruyama and Funabashi in the glassy state between 4.2 K and 77 K.
Krypton-85 in the Ocean
Authors: Schröder Jörg
Published: February 2015

A method is described to determine for the first time the 85 Kr concentration in seawater. Samples of 220 l of seawater are degassed aboard a research vessel. The krypton contained in the gas sample is isolated in the laboratory and its 8s Kr activity is measured in a gas counter. The background of the lowel-level counting-array is 0.026 cpm; surface water samples yield a netto count-rate of 0.13 cpm. The reproducibility of the method was checked by gas standards (krypton-air mixtures) and moreover by three surface water samples; both sets agree within ± 1 σ, or ± 5%. The mean value of three samples of great depths (1600, 2000, 2000 m) is 5% of the surface water concentration. This figure represents the possible contamination of the samples by atmospheric 85 Kr during the various preparation stages (blank value). Two profiles have been measured from the North Atlantic (about 40°N, 18°W, November 1972). A strong decrease of the 85 Kr concentration is found in the upper 1000 m. In a simple one-dimensional vertical diffusion-advection model the profiles can be simulated with a coefficient of apparent vertical eddy diffusion of 5 cm 2 / sec in the depth range of 300 to 1000 m (main thermocline). A possible application of oceanic 85 Kr data is the combination of depth profiles with those of other tracers, in particular 3 H. Another application of the 85 Kr method is the dating of groundwaters younger than 20 years.
Ground State Centrifugal Distortion Constants of Trans-Acrolein, CH2 = CH — CHO from the Microwave and Millimeter Wave Rotational Spectra 1,2
Authors: Winnewisser Manfred , Winnewisser Gisbert , Honda T. , Hirota E.
Published: February 2015

The pure rotational spectrum of trans-acrolein in the ground vibrational state has been assigned in the frequency region from 8 GHz to 180 GHz. The measured absorption lines encompass a-type transitions from the qRK, qQ1,
qQ2 branches and 6-type transitions from the rP0, rP1, rP2, rR0 brandies for values of J up to 23. The rotational constants have been refined and all quartic and sextic centrifugal distortion constants have been determined using Watson's reduced Hamiltonian. This information has been used to predict line positions of astrophysical interest to warrant the interstellar line search for trans-acrolein.
Notizen: Resonance Quenching of Anti-Stokes Luminescence from Rhodamine B in Water Solutions
Authors: Bojarski C. , Bujko A. , Dudkiewicz J. , Twardowski R.
Published: February 2015

It was found that when exciting the photoluminescence of water solutions of rhodamin B in the anti-Stokes region the concentrational changes of quantum yield decrease with the decreasing frequency of the exciting light.
Electron Temperature Determination from Non-LTE Populations in a Nitrogen Plasma JET
Authors: Catherinot A. , Sy A.
Published: February 2015

Atomic nitrogen electronic state populations and electron density have been measured in a high power nitrogen plasma jet in the pressure range 50 < P (Torr) < 150. A Boltzmann plot of the excited state populations led to electronic excitation temperatures depending on the groups of levels considered. Low and high lying levels yielded excitation temperatures which differed up to 80% at P = 120 Torr. The measured data are analysed in the frame of a two-temperatures diffusiondominated plasma model
Holographische Interferometrie zeitlich stationärer und instationärer Zustände / Holographie Inter}erometry of Stationary and lnstationary Processes
Authors: Neumann G. M. , Müller U. , Schmidt E.
Published: February 2015

The influence of instationary processes such as turbulences on the interference pattern of the well-known double-exposure technique for holography is shown. A new single-exposure technique is described which enables more detailed and direct information on instationarities in gas-flow. Examples are shown in which turbulences in gas-filled incandescent lamps can be detected by failure of the typical interference pattern when using the double-exposure technique or far better by direct appearance of black striations when using the single-exposure technique
Temperatur und Druck explodierender Drähte beim Verdampfungsbeginn / Temperature and Pressure of Exploding Wires at the Onset of Vaporization
Authors: Seydel U. , Schöfer R. , Jäger H.
Published: February 2015

Results of comparative investigations of the thermodynamic states of exploding wires in air and water under different pressures based on time correlated electrical and optical measurements are presented. From the energy input and from the "action integral", respectively, the time behaviour of the temperature up to the beginning of vaporization can be calculated with sufficient accuracy. Inbedding the wires in water especially under high static pressures leads to a remarkable increase of energy input up to the beginning of vaporization. In this way temperatures of more than 8000 K at homogenious conditions and solid state density could be realized
Temperaturabhängigkeit der Phosphor-HFS bei Iminophosphoran- Radikalen / Temperature Dependence of ESR-Phosphorus Coupling Constants of Iminophosphorane Radicals
Authors: Scheffler K. , Hieke S. , Haller R. , Stegmann H. B.
Published: February 2015

ESR-spectra of iminophosphorane radicals exhibit a strong temperature dependent coupling constant of the phosphorus nucleus. This splitting is described by a superposition of π-σ- and hyperconjugative interactions with the free electron. Because of hindered internal rotation of the iminophosphorane group the hyperconjugation term becomes temperature dependent. Differences in the phosphorus data of ortho- and para-iminophosphorane radicals respectively may be explained by a change of the potential barriers hindering the internal rotation
Principles of Trace Structure Analysis in Electron Microscopy
Authors: Hoppe W.
Published: February 2015

Structure analysis done with X-rays or with electrons, corresponds to an averaging of the specimen configuration over the exposure time. Such an analysis leads to the structure of the specimen only if the configuration does not change during exposure or if the change is negligible (stable molecule, crystal). Some time ago for instable configurations the method of "trace structure analysis" was proposed. The present paper explains the general principles of this method in detail. The static image of the structure will be divided into a dynamic succession of images along the time axis ("three-dimensional film"). But this division is not really characteristic for the method (it is in fact trivial). The main idea is to work with non-significant three-dimensional elementary structures and to use redundancies of the radiation induced physico-chemical processes for the combination of these elementary structures. Obviously these "redundancy laws" can only be unravelled in detail by trace structural work. It will be shown further that for special classes of these laws correlation analysis and pattern recognition procedures can be applied
A Note on the Generation of Twisting "D" Metrics from Non-Twisting "D" Metrics
Authors: Basey T. C.
Published: February 2015

Using a method of complexification of coordinates it is shown how certain of the Twisting "D" metrics may be obtained from corresponding Non-Twisting "D" metrics
Mass Renormalization and Chiral Symmetry Breaking in Nonlinear Spinor Theory
Authors: Bauhoff W. , Englert D.
Published: February 2015

The chiral invariance of conventional nonlinear spinor theory is assumed to be broken. This results in a finite mass renormalization of the nucleon mass. The self-consistency of the assumption is demonstrated. The meson mass eigenvalue equation is solved in lowest approximation. The spectrum which is no longer parity degenerate is in reasonable agreement with experiment.
53Cr Fourier Transform Nuclear Magnetic Resonance Studies
Authors: Epperlein B. W. , Krüger H. , Lutz O. , Nolle A. , Mayr W.
Published: February 2015

In various alkali chromate solutions in H2O and D2O the dependence of the Larmor frequency of 53Cr on the concentration of the solutions was measured by Fourier transform NMR and a large solvent isotope effect on the chemical shift of 53Cr was found. Further in potassium Chromate solutions the chemical shifts of 39K were observed and in a 2.2 molal solution of K2CrO4 in D2O a ratio of the Larmor frequencies of 53Cr and of 39K was measured with high accuracy. Using the concentration dependence of the Larmor frequencies of 53Cr and of 39K, an extrapolated ratio v(53Cr) /v (39K) extrapol. in infinitely diluted K2CrO4 in D2O is given. From this ratio a value of the magnetic moment of 53Cr in the Chromate ion is derived.

In chromium hexacarbonyl the 53Cr signal was observed and the chemical shift is given.
Microwave Spectrum and Barrier to Internal Rotation of 5-Methylisoxazole
Authors: Mjöberg P. J. , Ralowski W. M. , Ljunggren S. O.
Published: February 2015

The ground state rotational spectrum of 5-methylisoxazole has been studied in the region 18 000 -36 000 MHz. The A and E state transitions have been assigned.

The rotational constants are A = 9230.831 MHz, B = 3559.334 MHz and C = 2610.255 MHz and the three-fold barrier to internal rotation of the methyl group was calculated to be 777.2 ± 5.5 cal mol-1 .
Optische Spektren und Wanderungsmechanismen von Triplettexcitonen in reinen Naphthalinkristallen/Optical Spectra and Transport Mechanism of Triplet Excitons in Pure Naphthalene Crystals
Authors: Port H. , Wolf H. C.
Published: February 2015

Phosphorescence spectra of pure naphthalene and perdeutero-naphthalene crystals have been investigated between 4.2 and 300 K. Free-triplet exciton emission can be observed above 40 K only. The temperature dependence of phosphorescence line-width and line-shape has been studied between 60 and 300 K. With increasing temperature the lines are strongly broadened and become asymmetric. Above 150 K they show a red-shift (60 cm-1 at 300 K). The analysis is based on the decomposition of the lines into two components: an unshifted Lorentzian part resulting from coupled coherent and incoherent exciton motion and a sideband contribution built up with the phonon density of states of the naphthalene crystal. The Lorentzian line width is proportional to temperature. The degree of incoherence of exciton motion and characteristic parameters for the energy transfer mechanism are evaluated.
Zustandsdichte von Polaritonen in kubischen und einachsigen Kristallen / Density of States of Polaritons in Cubic and Uniaxial Crystals
Authors: Rath K. , Borstel G. , Lamprecht G. , Merten L.
Published: February 2015

The density of states of polaritons in cubic and uniaxial crystals is calculated. It is shown that closed mathematical expressions for the density of states of polaritons may be given. For uniaxial crystals the density of states of ordinary and extraordinary polaritons must be distinguished. With respect to extraordinary polaritons four different cases are possible
Untersuchungen mit der Linsenmethode über den Raumladungseinfluß auf den Richtstrahlwert / Investigations Performed with the Lens Method Concerning the Influence of Space Charge on Brightness
Authors: Lauer R.
Published: February 2015

According to earlier measurements with the two-aperture method, the brightness of electron guns has sometimes a maximum value near the cut-off potential. This result has been confirmed by means of the lens method. Experiments with well-oriented monocrystalline spherical cathodes lead to the result that a brightness maximum only occurs when the cathode apex has a lower emission density than its environment. In this case, the axial brightness is increased by electrons emitted from the off-axial cathode area which feed the space-charge cloud in front of the cathode. Under space-charge conditions, the cathode adjustment is not very critical, because the axial brightness differs less than the emission densities of different crystal surfaces
Dielektrische Relaxation von aliphatischen Kettenmolekülen mit endständigen Halogen-Gruppen in verdünnter Lösung / Dielectric Relaxation of α, ω-Halogen Alkanes in Dilute Solution
Authors: Klages G. , Straßmann M.
Published: February 2015

Dielectric loss in the 0.3 to 140 GHz range, and to some extent dispersion, of seven selected aliphatic chain molecules, substituted by Cl, Br, and I at both ends have been measured in dilute solutions of n-heptane, benzene, and decalin. Chain length varied from 3 to 10 carbon atoms. For 1,10-dichlorodecane in decalin and mesitylene the temperature was also varied from -30 to + 60 °C. The unsymmetric absorption curves have been resolved in a weak FIR region and a predominant region with a symmetric relaxation time distribution (log. scale) according to Fröhlich. The width of this distribution is shown to be independent of chain length and halogen. Its mean relaxation time increases linearly with chain length, while the dipole moment goes through a minimum for the butyl compounds.

Monoderivatives, three chlorides and one bromide, have also been measured in the same solvents at 20 °C. Their absorption curves can be fitted by a predominant absorption region with the same width as for the corresponding di-derivatives and, besides the FIR wing, by another low frequency Debye-region, the weight of which decreases with increasing chain length. The molecular motions related to these three regions are discussed, and the corresponding magnitudes of dipole moments in mono- and di-derivatives are compared for long and short chains
The Influence of Higher Order Modes upon the Accuracy of Dielectric Constant Determinations Using Transmission Measurement Cells for Electrolyte Solutions Having Strongly Depressed Dielectric Constants in the Gigahertz Range
Authors: Krüger J. , Schollmeyer E. , Barthel J.
Published: February 2015

The results of absorption measurements on aqueous electrolyte solutions (KF, KI and CsF) with high dielectric loss at five frequencies (8.25; 10.015; 11.88; 27.2 and 38.5 GHz) are reported. With the help of statistical data analysis methods the influence of the higher order modes on the accuracy of the data has been investigated. The use of measuring cells whose construction is based upon the theory of time independent, sourcefree ports, in connection with a highly precise amplitude receiver, allows the analysis of attenuation produced by these solutions. Interpretation of the data obtained using transmission techniques shows that the accuracy of such attenuation measurements is limited to 0.1% by higher order modes
Leitfähigkeitsmessungen an konzentrierten Alkalichlorid-und -nitratlösungen / Conductivity Measurements withConcentrated Solutions of Alkali Chlorides and Nitrates
Authors: Behret H. , Sdimithals F.
Published: February 2015

The conductivity of aqueous and non-aqueous liquid electrolyte solutions was determined in a low frequency region where no dispersion due to dielectric relaxation of the solvent-solute system can be found. The values of the equivalent conductance of concentrated alkali chloride and nitrate solutions were obtained by measurements in a special cell with high cell constant
Symmetrie-Gruppe eines geschlossenen Weltalls/ Symmetry Group of a closed Universe
Authors: Vollendorf F.
Published: February 2015

Symmetry Group of a closed Universe The fourteen degrees of freedom of a free falling and rotating body are described by means of a non-compact simple 14-parameter Lie group G14 . It is shown that this group can be interpreted as the symmetry group of a spherically closed space. Finally an outlook is made to the combination of an internal and an external symmetry group in a nontrivial way.
Electron Density Determination in an Are Plasma by Laser Interferometry
Authors: Brünger M. , Kock M.
Published: February 2015

By means of a 2 λ-Michelson-Interferometer the electron density has been determined with a mean accuracy of 2% in the axis of a wall-stabilized arc which has been operated in Argon at atmospheric pressure in a range from 10 to 100 A. The measurements have been performed with He-Ne-lasers at wavelengths λ1=0.63 μ and λ2 = 1.15 μ.
Functional Calculus of a Transferable Scalar in a Turbulent Flow
Authors: Ahmadi Goodarz
Published: February 2015

The problem of dispersion of a transferable scalar in a turbulent fluid is considered. The Hopf functional equation for the characteristic functional of the velocity vector and transferable scalar is derived and discussed. The special case of heat conduction with random initial condition is studied in detail. It is shown that the Hopf equation accepts a Gaussian characteristic functional solution and several examples are discussed.
Coupled Proton and Fluorine Nuclear Spin-Lattice Relaxation in Polycrystalline Magnesium and Zinc Fluorosilicate Hexahydrate
Authors: Jannek Horst-Dieter , Rager Helmut
Published: February 2015

Coupled proton and fluorine nuclear spin-lattice relaxation mechanisms have been studied in polycrystalline MeSiF6·6H2O (Me = Zn, Mg) at 30 MHz over the temperature range 130 K ≦ T ≦ 420 K. The results indicate that below 280 K in the magnesium complex and below 390 K in the zinc complex, respectively, the reorientations of the [SiF6]2- ions are the dominant relaxation mechanism. Reorientations of individual water molecules have not to be taken into account as an effective relaxation mechanism. The phase transition in MgSiF6·6H2O at 298 K is reflected by a change in the spin-lattice relaxation rate (T1)-1. In MgSiF6·6 H2O the relaxation behavior becomes purely exponential above the phase transition temperature, whereas in ZnSiF6·6H2O there is a non-exponential relaxation behavior over the whole temperature range investigated. The activation energies and frequency factors obtained from (T1)-1 measurements are consistent with the data obtained by use of the Waugh-Fedin relation.
Magnetische und Mößbauer-spektroskopische Untersuchungen von zeolithischen Eisenkontakten/ Magnetic and Mössbauer Spectroscopic Studies of Iron-Clusters in Zeolites
Authors: Schmidt F. , Gunsser W. , Knappwost A.
Published: February 2015

Iron clusters have been prepared within zeolite holes by reduction of zeolites containing ferrous ions. The diameter of these particles must therefore be smaller than 13 Å. They are super-paramagnetic and their Mössbauer spectra show no HFS, even at 4 K.

The temperature dependence of the magnetic susceptibility of the unreduced zeolites obeys a Curie-Weiss law with peff = 4,54 μB and Θ = 105 K. The Weiss curves of the reduced samples lie distinctly below those of the bulk material.
The Electrical Properties of Thin Films of TiNx and TiCx
Authors: De Maayer P. J. P. , Mackenzie J. D.
Published: February 2015

Thin films of metallically conductive titanium mononitride and carbide were prepared by means of electron beam evaporation. The composition of the samples could be changed over appreciable ranges by introducing nitrogen in the system or adding carbon to the pure starting material, respectively. The transport properties of the resulting compounds were studied as a function of nonstoichiometry and defect structure. A plausible explanation for the different behavior of the films compared to corresponding bulk samples is given and a correlation between the change in electron concentration and the electron transfer theory is presented.
Die Ringöffnungsreaktion des C3H3
+ -Ions/The Ring-opening Reaction of the C3H3
+-ion
Authors: Kebabcioglu R. , Dyczmons V.
Published: February 2015

The mechanism of the opening of the C3H3
+-ring was investigated by ab-initio SCF-calculations. In this ring-opening process the H-atoms move out of the CCC-plane. The reason for this is that for a CCC-angle of ≈ 90° a deformed π-system within the CCC-plane is formed. The reaction barrier is 83 kcal/Mol. The final result of the ring-opening is the linear propargyl cation.
Anwendung der Charakterordnungen zur Interpretation von Absorptionsspektren (N-Acylcarbazole)/ Application of Character Orders for the Interpretation of Absorption Spectra (N-Acyl-carbazoles)
Authors: Fratev Filip , Polansky Oskar E. , Zander Maximilian
Published: February 2015

Application For the first time character orders are applied to interprete absorption spectra: a high acetamid character order in N-acetylcarbazole explains the blue shift observed. The hypsochromic effect of acyl groups in such compounds is clarified. Also an explanation of the changes of CO stretch frequencies is given on the basis of character orders.
Kernresonanzuntersuchung der Molekülrotation und Selbstdiffusion in festem Benzol: T1ϱ-Spektroskopie/ Nuclear Magnetic Resonance Investigation of Molecular Rotation and Diffusion in Solid Benzene: T1ϱ-Spectroscopy
Authors: Noack F. , Weithase M. , Schütz J. von
Published: February 2015

We have extended previous NMR investigations of the molecular motion in solid benzene to lower proton spin Larmor frequencies using the rotating frame (T1ϱ) technique. The new data show two relaxation mechanisms, namely the well-known rotation of the benzene rings around their sixfold axis and, additionally, the self-diffusion by vacancies. The rotation and diffusion was analyzed by computer optimization of the relaxation models of Haeberlen and Torrey, respectively. The parameters of rotation are essentially consistent with results derived recently from high-frequency T1 measurements. The diffusion parameters are in agreement with preliminary low-frequency T1 measurements, but reveal a dramatic discrepancy by nearly 4 orders of magnitude with respect to tracer experiments of Fox and Sherwood. This behaviour is discussed in terms of correlation effects similar to those observed in plastic and liquid crystals.
Notizen: Sign Reversal of Thermo EMF on Hydrogen Diffusion in thin Nickel Foils
Authors: Nigam Amar Nath , Rani Ratna
Published: February 2015

On cathodic hydrogen diffusion thin foils of nickel (6 micron thickness) show a sign reversal in their thermo electric power. The original value -17 μV/ °C changes to + 3μV/°C after diffusion. The results are interpreted in terms of a possible 4p band filling by the electrons donated by hydrogen. Annealed foils retain hydrogen longer than the unannealed ones.
Notizen: Grünleuchtende Zentren im "kalt" aktivierten ZnS-Pb/Green Luminescent Centres in "Cold" Activated ZnS-Pb
Authors: Kynev K. , Dafinova R.
Published: February 2015

Green luminescent zinc sulphide activated with lead has been prepared by coprecipitation. A surface sensitivity of the emission spectrum is established and a participation of adsorbed ions in the luminescent centres located on the surface is assumed.
Notizen: Quantum Chemical Investigations on the Structure of the Gas Phase Ion Solvates M+(DMF-CH3
+)
Authors: Rode B. M. , Ahlrichs R.
Published: February 2015

The structure of the dimethylformamide fragment (DMF-CH3
+) and its complexes with Li+ and Na+ being observed in low pressure gas phase solvation has been investigated by means of ab initio SCF calculations with two different basis sets. Stabilization energies, charge transfer and polarization effects upon complex formation are discussed.
The Electric Conductivities and Densities of Molten SnCl2-ZnCl2 Binary Mixtures
Authors: Mentus S. V. , Šušić M. V.
Published: February 2015

The specific electric conductivities and densities of molten ZnCl2 -SnCl2 binary mixtures were measured as a function of composition in the temperature range 260 -530 °C. The electric con-ductivities show small, mainly negative, deviations from additivity. The densities show positive deviations from additivity, especially in the SnCl2-rich composition range. The structural properties of the melts causing such a behaviour are discussed.
Berechnung der freien Exzeßenergie und des osmotischen Koeffizienten zur Gewinnung von Potential-Parametern kurzreichender Wechselwirkungen bei Elektrolytlösungen
Authors: Schollmeyer Eckhard
Published: February 2015

Short-range interactions of Electrolyte Solutions Short range interaction potentials between ions are approximated by a step function with a hard core. Then from general statistical-mechanical formulas the first correction to the limiting law of the free excess energy F* (S(2) -term of the cluster theory) is computed for low concentrations, i.e. small plasm parameter μ=e2 x/D0 kT ⪡ -. Fitting to a Lennard-Jones potential for symmetrical electrolytes results in values for F*, the osmotic pressure and the osmotic coefficient. Numerical fitting to experimental results of Lange for the osmotic coefficient gives information concerning the contact distance a and attraction parameter E for some water-tetraalkylhalogenide-systems.