bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elektronen-Spin-Resonanz und ENDOR-Messungen an Fe3+ und Cr3+ in Zinndioxid
Authors: Rhein W 
Published: February 2015

Abstract
ESR measurements on Fe3+ and Cr3+ at interstitial sites in SnO2 show that two of the magnetic main axes form an angle of 0.7° to the crystallographic axes. Additional information as to which kind of sites are occupied is yielded by ENDOR measurements of the Fe57, Cr53 hyperfine inter-action, and of the superhyperfine interaction with neighbouring Sn-ligands. It is, furthermore, shown that hydrogen is present in the immediate surroundings of both 3d-ions at interstitial sites
Einige Bemerkungen über die Erzeugung von elektromagnetischen Wanderwellen und stehenden Wellen zur induktiven Plasmabeschleunigung
Authors: Meert A 
Published: February 2015

Abstract
Some comments are made for the generation of e.m. travelling and standing waves used for in-ductive plasma acceleration. Resulting from a simple mathematical formulation the different features lead to a non-conventional method for travelling wave generation, which is compared with the basic method - i. e. the standing wave generation - with regard to Ohmic losses and mag-netic energy density
Relaxation Phenomena in the Biological Carbon Cycle under Conditions of Variable Atmospheric CO2 -Content
Authors: Wagener K , Forstel H 
Published: February 2015

Abstract
Under normal conditions the carbon cycle is a stationary process. A varying CO2 partial pres-sure would cause deviations from the steady state. This process is analysed using a differen-tiated flow scheme of the carbon through the biosphere. For this purpose the biomass on land is divided into three reservoirs with average fixation times of 1 day (day-night-cycle), 2 years (annual period), and 100 years (timber, humus), respectively. The kinetic analysis shows that about 70% of the global respiration follow fluctuations of the rate of photosynthesis immediately, so that this portion of the excess of fixed carbon will be returned in the atmosphere within a few years. Only 30% of the total cycle passes through the largest reservoir (timber, humus) which could serve as a buffering system. But since the time constant of this partial cycle is about 100 years, the CO2 exchange with the ocean is the faster process
Protonenrelaxation und dynamische Kernpolarisation in Metall-Ammoniaklösungen
Authors: Mehner A.-W , Müller-Warmuth W 
Published: February 2015

Abstract
Relaxation times and Overhauser enhancements for protons in metal (K, Li, Na, Ca) ammonia solutions have been measured at 176, 3400 and 11 200 G over a wide range of concentrations and temperatures. Both the relaxation rate due to the interaction with unpaired electrons and the Overhauser coupling parameter are strongly frequency-dependent and undergo a characteristic change at metal concentrations of 0.05 - 0.5 M. They can be explained by a mixed scalar and di-polar coupling. Coupling amplitudes, spectral intensity functions and correlation times with their temperature-dependence have been determined. The results and a comparison with Knight shift data show that more than one paramagnetic species in the solution, and different mechanisms of relative motion between protons and electrons must contribute. The major part of the coupling is of a short range type, where the electrons, by some kind of tunneling, are the carriers of the motion. The discussion postulates dissolved electrons with rather flexible solvation spheres where spin density is greatly smeared out. The second paramagnetic species may be the "monomer" often dis-cussed in the literature. Additional experiments which support our conclusions have concerned the self diffusion coefficient of the protons, and the Overhauser enhancement of lithium-7
Zur nukleon-nukleon-s-streuung. Ii. der numerische stabilitätstest / On nucleon-nucleon s-scattering. ii. the numerical stability test
Authors: Drumm H , Trübenbacher E 
Published: February 2015

Abstract
On Nucleon-Nucleon S-Scattering. II. The Numerical Stability Test The numerical stability test is discussed which prevented the decision on the usefulness of a non-relativistic nucleon-nucleon potential of a previous paper, and this decision is finally accomplished by fulfilling the stability condition
Die bildung unsymmetrischer excimerer zwischen pyren und 4.5-iminophenanthren / Pyrene and 4.5-iminophenanthrene form unsymmetrical excimers in cyclohexane solutions
Authors: Steidl H. , Hoffmann G. 
Published: February 2015

Abstract
Aromaten bilden mit einigen ihrer Derivate unsym- metrische Excimere1. Ob unsymmetrische Excimere auch zwischen dem aromatischen Pyren (I) und dem heteroaromatischen, zu Pyren isoelektronischen 4.5- Iminophenanthren (II) gebildet werden, soil hier un- tersucht werden. Da beide Molekiile nahezu gleiche Elektronenanregungszustande haben2, jeweils sym- metrische Excimere bilden 1,3 und (II) 4 ebenfalls wie (I) ein planares Molekiil ist, erscheint es naheliegend, die Bildung unsymmetrischer Excimerer zwischen (I) und (II) zu erwarten. Abbildung 1 zeigt die Struktur- formeln beider Molekiile
The Ground State Energy of the Hubbard Model in Hubbard's Approximation
Authors: Jelitto Rainer 
Published: February 2015

Abstract
We have calculated the ground state energy of the Hubbard model in the approximation of Hubbard's first paper1 . For the neutral model with nearest neighbour interaction the energy resulting from the selfconsistent paramagnetic solution is compared with those ones following from the (ferromagnetic) Hartree-Fock and an (antiferromagnetic) single particle theory. The energy of the latter one turns out to be the best approximation of the true ground state energy of the model for all values of the coupling constant V0 , but the energy derived from Hubbard's approximation, in spite of the absence of magnetic ordering, is a reasonable approximation at least for sufficiently large values of V0.
Elastic Constants of Nematic Liquid Crystals
Authors: Gruler Hans , Scheffer Terry J. , Meier Gerhard 
Published: February 2015

Abstract
We present a theoretical treatment and give experimental observations of the deformation that occurs in a nematic liquid crystal when electric or magnetic fields are applied. We consider only normal deformations in the nematic material where fluid flow and other dynamic phenomena play no role. Three important sample geometries are considered in the magnetic field, and the experimentally observed deformations are in good agreement with theory. The normal deformation induced by electric fields is of interest from a device standpoint, and we give a solution for the deformation that is valid even for large dielectric anisotropics. This solution has been experimentally verified. We give a detailed comparison of the distortions produced by electric and magnetic fields and show that the deformations are of a similar form even though the field is nonuniform in the electric case. The change in birefringence and electrical capacitance as a function of distortion is discussed as a means of observing the deformation.
Microwave Spectrum and Quadrupole Coupling Constants of Orthochloropyridine
Authors: Scappini F , Guarnieri A 
Published: February 2015

Abstract
The rotational spectrum of 2-chloropyridine was measured in the region between 8-40 GHz. The rotational constants for the vibrational ground state are:
A = 5872.01 ± 0.02 MHz, B = 1637.82 ± 0.02 MHz, C=1280.51 ± 0.02 MHz.
The value 0.0385 amu · A2 of the inertia defect indicates a planar nuclear frame. From the hyper-fine splittings of the rotational lines the nuclear quadrupole coupling constants of 35Cl were determined. The values are:
χaa = 70.79 ± 0.17 MHz, χbb = 39.01 ± 0.45 MHz, χcc = 31.78 ± 0.62 MHz.
Notizen: Empirical Evidence for Shell Effects in (n,p)- and (n,α)-Reaction Cross Sections Induced By 14 Mev Neutrons
Authors: Holmberg P. 
Published: February 2015

Abstract
Cross section values for (n,p)-and (n,α)-reactions have been analysed as functions of the proton and neutron numbers of the target nuclei. When these numbers equal or approach those of a closed shell structure, the cross section values tend to increase. Far from closed shells the cross sections are small.
Elastische und thermoelastische Konstanten des LiBaF3 / Elastic and Thermoelastic Constants of LiBaF3
Authors: Haussühl S. , Leckebusch R. , Recker K. 
Published: February 2015

Abstract
The elastic and thermoelastic constants of cubic LiBaF3 are measured by ultrasonic methods. As a consequence of the larger packing density which results from the higher coordination number of the Ba ions in LiBaF3 the values for the mean elastic stiffness and for the refractive index exceed those of LiF and BaF2 . A quantitative explanation of these properties is given. The values of many other properties range between those of LiF and BaF2.
Non-Equilibrium Thermodynamics of Phase-Transitions
Authors: Waldmann L , Rübsamen R 
Published: February 2015

Abstract
The entropy production - (3.8.) - in the boundary between two phases of a one-component system contains two scalar force-flux pairs. The "forces" are the jumps of the temperature and of (essentially) the chemical potential at the interface; the "fluxes" are the heat and mass fluxes nor-mal to the interface. So, four phenomenological coefficients appear in the pertaining local linear constitutive laws - (4.14 and 15) - for the boundary conditions. They can in principle be de-termined by a stationary heat conduction and phase transition experiment. Only measurements of temperature jumps - (5.14 and 15) - are involved. These jumps vanish if the four coefficients vanish
The Sulfur Dioxide Photosensitized cis-trans Isomerization of Butene-2 The Quenching Effect of Oxygen and Nitric Oxide
Authors: Penzhorn R.-D. , Güsten H 
Published: February 2015

Abstract
Rate constants were determined for the quenching reaction of excited triplet sulfur dioxide (3SO2) with the typical triplet quenchers oxygen and nitric oxide, employing the sulfur dioxide photosensitized cis-trans isomerization of butene-2. While the rate constant for 3SO2 quenching by nitric oxide (k=7.8±1.9x1010 liters/mole sec) is near the collision number, the rate constant for quenching by oxygen (k=2.4±0.5x108 liters/mole sec) is surprisingly low. The possible signi-ficance of these quenching processes on aerosol formation in photochemical smog is discussed.
Massentrennung in kondensierten Molekularstrahlen durch Wechselwirkung von Clustern und unkondensiertem Restgas
Authors: Becker E. W. , Gspann J. , Körting K. 
Published: February 2015

Abstract
The spatial mass distribution of the clusters in condensed molecular beams of nitrogen produced with one-sided beam guidance are studied by using an accelerating-field time-of-flight arrangement. In the range investigated the mean number of molecules per cluster increases monotonously by about two orders of magnitude with decreasing distance from the guiding plane. The strong spatial mass separation can be explained by the interaction of the clusters with a flow of uncondensed gas expanding out of the collimator.
Calculation of the Correlation Factor for Diffusion in the Diamond Structure Including Electrostatic Impurity-Vacancy Interaction
Authors: Barker H. , Mirani H 
Published: February 2015

Abstract
An expression for the correlation factor of impurity diffusion in the diamond structure as a function of five distinct atom-vacancy exchange rates is derived.
Furthermore, the effect on the correlation factor of electrostatic vacancy-impurity interaction is included in the calculation. Differences with results obtained by other authors are discussed.
Ein Vergleich von Eigenkanal-und R-Matrix-Theorie
Authors: Petzold R. , Grauel A. 
Published: February 2015

Abstract
The convergence of the eigenchannel (EK) and R-matrix (RM) theories - depending on their free parameters - is numerically investigated by comparing with a simple, analytically solvable model. The comparison shows that the results of the EK-theory are in general closer to the exact solution than those of the RM-theory. Especially in regions of sharp resonances the dependence of the expansion of the wave functions on the interaction radius ac and on the boundary condition Bc is very strong in the RM-theory and one needs very many levels to achieve good results.
Notizen:Elastische und thermoelastische Konstanten von Gadolinium-Gallium-Granat Gd3Ga5012
Authors: Haussühl S , Mateika D 
Published: February 2015

Abstract
The elastic and thermoelastic constants of cubic Gd3Ga5O12 are measured by ultrasonic methods. The differences in the elastic behaviour between this garnet and other synthetic garnets are very small; they may be partially explained by the r-4-rule which is valid in other ionic crystals of cubic symmetry.
Notizen: NQR-Untersuchungen an Charge-Transfer- Komplexen mit einer N-J-Bindung / NQR-Studies of Charge-Transfer-Complexes Containing a N-I-Bond
Authors: Brüggemann R. , Reiter F. , Voitländer J. 
Published: February 2015

In a number of charge-transfer-molecules containing a N-I-bond we have found NQR-transition-frequencies of the I-atom adjacent N in the range between 300-970 MHz (Table 1).
The used spectrometer works automatically and it is possible to cool the sample with liquid nitrogen even at highest frequencies.
We have tried to interpret the results using MO-theory. Especially it was shown that the σg-orbital in I-I contributes to the bond in the three-centre-system N-I-I. This fact does not agree with calculations in LCMO-theory, which is the MO-analoge of the Mulliken-VB-theory. According to Mulliken the contribution of the σg-orbital of I-I is equivalent to a polarisation of the I-I-molecule interacting with the donor.
CNDO/2-Elektronenladungsdichten und 13C-chemische Verschiebungen von Phenylacetylenen / CNDO/2-Electron Charge Densities and 13C-Chemical Shifts of Phenylacetylenes
Authors: Klasinc L , Knop J.V. , Meiners H.-J , Zeil W 
Published: February 2015

Abstract
The 13C FT NMR spectra of phenylacetylene (1), p-methoxyphenylacetylene (2), p-fluorophenyl-acetylene (3), p-chlorophenylacetylene (4), p-bromophenylacetylene (5), p-ethylphenylacetylene (6) and p-isopropylphenylacetylene (7) as well as of a number of monosubstituted benzenes have been measured. The 13 C-chemical shifts in these compounds are correlated with the total charge densities at the corresponding carbon atoms, calculated by the CNDO/2 method. The present results show that a simple additivity exists between 13C-chemical shifts in substituted benzenes, phenylacetylene and substituted phenylacetylenes and that practically no charge transfer between the linked sub-stituted phenyl and the ethinyl groups takes place. The interaction of the ethinyl substituent and the π-electron system can mainly be attributed to inductive effects.
Theory of Damped Polaritons
Authors: Merten L , Borstel G 
Published: February 2015

Abstract
The basic equations of damped polaritons in orthorhombic crystals and those of higher symmetry are set up. From these basic equations a general dispersion equation for the complex frequencies (real frequency and damping factor) is derived.
Essential differences of the dispersion curves are demonstrated for the case of purely temporally damped polaritons (ω complex, k real) and of purely spatially damped polaritons (ω real, k com-plex). A detailed discussion and numerical evaluations are given for ZnF2 as an example.
On the Motion of Small Spheres in Gases. I. General Theory
Authors: Williams M.M.R. 
Published: February 2015

Abstract
We have developed a global scattering kernel which describes the scattering of gas atoms by spherical particles which are small compared with a mean free path in the gas. The global kernel, which is analogous in many ways to the thermal neutron scattering kernel employed in neutron thermalization studies, is given in terms of the gas-surface scattering law for the particle. Thus the global kernel can be studied as a function of specular reflection and incomplete accommodation. The recent model of KUŠČER and of CERCIGNANI is used for the latter investigation and we find that on the average the angular distribution of the scattered gas atoms depends sensitively on the tangential momentum accommodation coefficient but only very weakly on the energy coefficient. However, the phenomenon is strongly dependent on the speed of the approaching gas atom and, for low speed gas atoms, the sensitivity to energy accommodation becomes much more important.
The net scattering rate is obtained and put in a form convenient for later calculations to be described in a series of companion papers.
On the Motion of Small Spheres in Gases. II. Thermo-phoresis, Diffusio-phoresis and Related Phenomena
Authors: Williams M.M.R. 
Published: February 2015

Abstract
Using the general theory developed by the author in the previous paper, the problems of thermo-phoresis and diffusio-phoresis have been examined with a view to elucidating the effect of a general gas-surface scattering law on the associated forces. It is found that, in thermo-phoresis, there exists a close coupling between the first anisotropic moment of the gas-surface scattering law and the solution of the Chapman-Enskog conductivity equation. Explicit calculations indicate that for an arbitrary combination of any type of purely elastic scattering, e. g. specular, Lambert or backward, there is no change in the creep velocity of the particle. On the other hand, diffuse scattering with redistribution, leads to a marked decrease in the creep velocity. These conclusions are independent of the force law between gas atoms and depend only on the gas-surface interaction.
In diffusio-phoresis, using only the simplest Chapman-Enskog solution for a binary mixture, it is found that unless the gas-surface laws differ greatly for the two species, there is virtually no influence of gas-surface scattering on the particle motion: the effect is due almost entirely to the mass difference and concentration ratio.
We also investigate the way in which particles move in gas streams close to boundaries; slip flow is used as an example and it is shown that for diffuse reflection a particle at the wall travels with a speed which is about 60% of the gas speed at the wall.
Orbital Valence Force Field Constants of Tetrachlorides, Tetrabromides and Tetraiodides of Titanium, Zirconium and Hafnium
Authors: Pandey A. N. , Sharma D. , Mital H. 
Published: February 2015

Abstract
The orbital valence force field has been employed to calculate the force constants for tetra-chlorides, tetrabromides, and tetraiodides of titanium, zirconium, and hafnium making use of recent vapor-phase Raman spectral data. The results are compared with the Urey-Bradley force constants, and it has been found that these are well comparable. The applicability of the Lennard-Jones potential has been examined to understand the nature of non-bonded interactions. The force constants have also been utilized to study the relative strength of the chemical bonds in tetrahalides and hexahalide anions
Die Bestimmung der Terme äquivalenter Elektronen bei LS-Kopplung / Determination of Terms for LS-coupled Equivalent Electrons
Authors: Kleindienst Heinz 
Published: February 2015

Abstract
In this paper a simple method for the determination of all antisymmetric terms allowed according to Pauli principle is presented. Using group theory it allows to evaluate the terms for all electronic configurations of the type lr with l≦ 3.
Altersbestimmung nach der K-Ca-Methode an Sylvin des Oberen Zechsteines des Werragebietes Potassium
Authors: Wilhelm Hans G. , Ackermann Wilhelm 
Published: February 2015

Abstract
The potassium-calcium age determination method was applied to two sylvite samples from the upper Zechstein salinar deposit of the Werra region, Germany. Age values were obtained of 133 million years for one sample and of 40.5 million years for the other one, a recrystallised sample.
Massenspektrometrische Analyse der Hg2
+ -Bildung in der positiven Säule der Hg-Ar-Niederdruckentladung / Mass-spectrometric Analysis of Hg2
+ Formation in the Positive Column of the Mercury-Argon Low Pressure Discharge
Authors: Franck G. , Lüdemann H. 
Published: February 2015

The ions effusing ambipolar out of the positive column of a mercury-argon low pressure dis­charge are analyzed in a quadrupol mass spectrometer. Besides the Hg+-ion we find the Hg2
+-ion molecule. The measured current ratio i(Hg2
+)/i(Hg+) in the mass spectrometer is proportional to the mercury vapour pressure pHg in the discharge. i(Hg2
+)/i(Hg+) lies between 10-2 at pHg = 10-3 Torr and 1 at pHg = 0.1 Torr. - At constant argon- and mercury pressures i(Hg2
+)/i(Hg+) is inversely proportional to the discharge current. - At constant discharge current and mercury vapour pressures the ratio i(Hg2
+)/i(Hg+) is nearly independent of the argon pressure.
An analysis of our measurements with the help of balance equations for excited Hg-atoms in the resonance level (3P1) and in the metastable 3P0 and 3P2 levels is carried out. It turns out that the only relevant process leading to the Hg2
+*ion molecule is the reaction
Hg*+ Hg*→ Hg2
++e
of Hg-atoms in the levels 3P0, 3P1 and 3P2. It can be shown that the Hornbeck-Molnar-process Hg**+Hg → Hg2
++e and the reactions Hg++2Hg→Hg2
++ Hg, Hg++Hg+Ar→Hg2
++Ar play an unimportant role in the Hg2
+-ion formation.
Improved Uncoupled Hartree-Fock Perturbation Theory. V. Electric Dipole Polarizabilities of 12-and 18-Electron Atomic Systems
Authors: Sadlej Andrzej J. 
Published: February 2015

Abstract
The variation-perturbation uncoupled Hartree-Fock scheme is applied to the calculation of the electric dipole polarizabilities of Mg and Ar-like atomic systems. The results are compared with more elaborate coupled Hartree-Fock calculations and with experimental data and indicate the validity of the method.
Zur Biochemie der Schilddrüsenfunktion V: Der Einfluß substituierter Thioharnstoffe auf die Kaninchenthyreoidea
Authors: Hüter Friedrich 
Published: February 2015

Bei langdauernder Injektion von Benzylthioharnstoff, der schwer resorbiert wird, entsteht beim Kaninchen keine Struma baśedowificata, sondern nur ein Präbasedow-Zustand. Eine Aktivierung der Schilddrüsen(SD)-Follikel tritt bei kurzfristiger Verfütterung von Benzylthioharnstoff auf.
Der symm. Dibenzylthioharnstoff erzeugt bei täglicher Injektion ein Vorstadium der Struma diffusa parenchymatosa. Seine Resorption ist schlecht.
Die Isothioharnstoffe sind für den Tierversuch wahrscheinlich zu giftig.
Thiouracil, subcutan gespritzt, ruft SD-Vergrößerung hervor und ist bei weitem nicht so toxisch wie Allylthioharnstoff. Die Größen der entarteten Drüsen sind den zugeführten Thiouracilmengen nicht proportional und meines Erachtens von der Konstitution der Versuchstiere weitgehend abhängig.
2-Thio-barbitursäure wirkt bei einer Injektion über drei Monate schwach schilddrüsenaktiv.
Die Natriumsalze des S-Kupfer-N-Allyl-N'-[m-carboxyphenyl]-iso-thioharnstoffes (Cuprion) und des S-Gold-N-Allyl-N'-[m-carboxyphenyl]-iso-thioharnstoffes (Lopion), parenteral gegeben, üben einen nachteiligen Einfluß auf die Schilddrüse aus. Lopion wird besser als Cuprion vertragen. Der N-Allyl-N'-[m-carboxyphenyl]-iso-thioharnstoff wird offenbar schnell vom Körper ausgeschieden, weshalb große Mengen des Grundkörpers erforderlich sind, um eine stärkere SD-Aktivität hervorzurufen.
Sulfanilylthioharnstoff verändert ein wenig die Kaninchen-SD, wenn er über zwei Monate verabfolgt wird.
Mengt man Sulfanilylguanidin dem Futter bei, dann wird die SD in geringem Grade aktiviert. Eine leichte Hypertrophie der Drüse wurde bei subcutaner Behandlung eines Tieres festgestellt.
Möglicherweise führen unter gewissen Bedingungen Benzylthioharnstoff, Sulfanilylguanidin, Cupro-N-Allyl-N'- [m-carboxyphenyl]-iso-thioharnstoff und Thiouracil, in dieser Reihe zunehmend wirksam, zu einer SD-Hypertrophie.
Die Art und Weise, wie die Kaninchen auf die schilddrüsenwirksamen Substanzen reagierten, weist auf die Entwicklung eines anormalen Zustandes der Thyreoidea hin. Unsere Befunde stehen mit der Erklärung der thyreostatischen Wirksamkeit chemischer Verbindungen durch amerikanische Autoren in Einklang.