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1997[X]
61Author    MichaelC. Böhm, Joachim Schulte, Robert SchlöglRequires cookie*
 Title    An ab initio Study of the C 60 Particle-Hole Pair + and Cjj"  
 Abstract    The C 60 ions C^ 4 " and C^ -are discussed comparatively on the basis of ab initio calculations. The basis set employed is of 3-21 G* quality. By analogy with the neutral molecule the geometry of the anion is icosahedral (I h). Both I h systems differ, however, in the bondlength alternation. In the neutral molecule the hexagon-hexagon bondlength exceeds the hexagon-pentagon value; vice versa in the anion. C^ is of C s symmetry with a strong intermixing in the length of the two types of CC bonds. Calculated geometries, total energies and net charges are adopted to evaluate differences in the electronic structure of C^ and . 
  Reference    Z. Naturforsch. 52a, 331—334 (1997); received January 9 1997 
  Published    1997 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0331.pdf 
 Identifier    ZNA-1997-52a-0331 
 Volume    52 
62Author    Yi-Tian Gao, Bo TianRequires cookie*
 Title    On the Variant Boussinesq Equations  
 Abstract    We extend the generalized tan h method to the variant Boussinesq equations and obtain certain solitary-wave and new exact solutions. 
  Reference    Z. Naturforsch. 52a, 335—336 (1997); received June 27 1996 
  Published    1997 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0335.pdf 
 Identifier    ZNA-1997-52a-0335 
 Volume    52 
63Author    J. Seliger, V. ŽagarRequires cookie*
 Title    A New Nuclear-Quadrupole Double-Resonance Technique based on Solid Effect  
 Abstract    A new nuclear-quadrupole double-resonance technique is described. It has a higher sensitivity and a higher resolution than the conventional nuclear-quadrupole double-resonance technique based on solid effect. The new technique involves magnetic field cycling between a high and a low static magnetic field and simultaneous application of two //magnetic fields when the sample is in the low static magnetic field. A strong rf magnetic field induces "forbidden" simultaneous transitions in a magnetic (usually 1 H) and in a quadrupole spin system and thus couples the two spin systems. A weak//magnetic field induces transitions between the energy levels of the quadrupole nuclei and simulates a fast spin-lattice relaxation of the quadrupole nuclei when its frequency matches an NQR frequency. The sensitivity and resolution of the new technique are discussed and test measurements in tris-sarcosine calcium chloride are presented. 
  Reference    Z. Naturforsch. 52a, 337—342 (1997); received October 9 1996 
  Published    1997 
  Keywords    NQR, NMR, Double Resonance, Magnetic Field Cycling, Solid Effect 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0337.pdf 
 Identifier    ZNA-1997-52a-0337 
 Volume    52 
64Author    P. Käuper, V. Göbbels, P. Blümler, B. BlümichRequires cookie*
 Title    Two-Dimensional NQR Spectroscopy for the Characterization of Crystalline Powders  
 Abstract    Two-dimensional NQR spectroscopy for correlation of homogeneous and inhomogeneous linewidths has been applied to the 35 C1 resonance of sodium chlorate powders of different origin. Powder from a ground crystal could be discriminated from technical powder by the ratio of linewidths along the two orthogonal axes in the 2D spectrum. These experiments indicate the applicability of NQR spectroscopy in material science. 
  Reference    Z. Naturforsch. 52a, 343—347 (1997); received December 20 1996 
  Published    1997 
  Keywords    Material science, NQR, Sodium chlorate, 2D spectroscopy, Separation of interactions 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0343.pdf 
 Identifier    ZNA-1997-52a-0343 
 Volume    52 
65Author    C. Margheritis, A. Marini, C. SinistriRequires cookie*
 Title    Thermodynamics of /J-cyclodextrine/water Interactions  
 Abstract    From a purely enthalpic standpoint, the ß-CD hydration, as studied by semiempirical calcula-tions, appears improbable, in contrast to experiment. For the spontaneous hydration process, a compensation mechanism, connected with substrate stabilization and/or entropy increase, is sug-gested on the basis of simple thermodynamic considerations. The analysis is done on the basis of a single parameter £ w (> 0), which represents the energy needed to transfer a mole of water from the liquid to the ß-CD absorbed phase. The model, although simple, allows predictions largely consistent with the experimental results, while suggesting possible interpretations. 
  Reference    Z. Naturforsch. 52a, 348—350 (1997); received January 3 1996 
  Published    1997 
  Keywords    ß-cyclodextrine, Water interactions, Thermodynamics 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0348.pdf 
 Identifier    ZNA-1997-52a-0348 
 Volume    52 
66Author    A. Kondoh, T. OiRequires cookie*
 Title    Interaction of Alkaline Earth Metal Ions with Acetic and Lactic Acid in Aqueous Solutions Studied by 13 C NMR Spectroscopy  
 Abstract    Interaction of alkaline earth metal (magnesium, calcium, strontium and barium) ions with acetic and lactic acid in aqueous media was investigated by 13 C NMR spectroscopy. In the acetate systems, signals whose chemical shifts were the averages of those of the free and bound acetate ions were observed. Downfield shifts of the carboxylate carbon signals with increasing metal ion concentration indicated that the acetate ion acted as a monodentate ligand coordinating to the metal ion using the carboxylate group. The metal ion concentration dependence of the peak positions of the methine and carboxylate carbon signals of the lactate ion in the lactate systems suggested that the lactate ion coordinated to a metal ion using the carboxylate and hydroxyl groups. Unique upfield shifts upon complexation in the magnesium lactate systems suggested that the lactate ion coordinated to the magnesium ion from outside the primary hydration sphere. The present results were consistent with the isotope effects of the alkaline earth metals observed in cation exchange chromatography. 
  Reference    Z. Naturforsch. 52a, 351—357 (1997); received December 4 1996 
  Published    1997 
  Keywords    13 C NMR, Alkaline Earth Metals, Acetic Acid, Lactic Acid, Isotope Effects 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0351.pdf 
 Identifier    ZNA-1997-52a-0351 
 Volume    52 
67Author    Michio Nishida, Masashi MatsumotoRequires cookie*
 Title    Thermochemical Nonequilibrium in Rapidly Expanding Flows of High-Temperature Air  
 Abstract    • This paper describes a computational study of the thermal and chemical nonequilibrium occuring in a rapidly expanding flow of high-temperature air transported as a free jet from an orifice into low-density stationary air. Translational, rotational, vibrational and electron temperatures are treated separately, and in particular the vibrational temperatures are individually treated; a multi-vibrational temperature model is adopted. The governing equations are axisymmetric Navier-Stokes equations coupled with species vibrational energy, electron energy and species mass conservation equations. These equations are numerically solved, using the second order upwind TVD scheme of the Harten-Yee type. The calculations were carried out for two different orifice temperatures and also two different orifice diameters to investigate the effects of such parameters on the structure of a nonequilibrium free jet. 
  Reference    Z. Naturforsch. 52a, 358—368 (1997); received June 26 1996 
  Published    1997 
  Keywords    Thermal Nonequilibrium, Chemical Nonequilibrium, High Temperature Air, Free Jet, Computational Fluid Dynamics 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0358.pdf 
 Identifier    ZNA-1997-52a-0358 
 Volume    52 
68Author    R. C. Sharma, P. KumarRequires cookie*
 Title    Thermal Instability in Rivlin-Ericksen Elastico-Viscous Fluids in Hydromagnetics  
 Abstract    The thermal instability of a layer of Rivlin-Ericksen elastico-viscous fluid acted on by a uniform vertical magnetic field is considered. For stationary convection, a Rivlin-Ericksen elastico-viscous fluid behaves like a Newtonian fluid. The magnetic field has a stabilizing effect. It is found that the presence of a magnetic field introduces oscillatory modes which were non-existent in its absence. The sufficient condition for the non-existence of overstability is also obtained. 
  Reference    Z. Naturforsch. 52a, 369—371 (1997); received January 17 1996 
  Published    1997 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0369.pdf 
 Identifier    ZNA-1997-52a-0369 
 Volume    52 
69Author    Bo Tian, Keyi Zhao, Yi-Tian GaoRequires cookie*
 Title    Modification of the Generalized tanh Method with sech Function for Generalized Hamiltonian Equations  
 Abstract    We modify the generalized tanh method with the sech function, so as to obtain a new class of the soliton-like solu-tions to a coupled set of generalized Hamiltonian equations. 
  Reference    Z. Naturforsch. 52a, 372 (1997); received January 9 1997 
  Published    1997 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0372_n.pdf 
 Identifier    ZNA-1997-52a-0372_n 
 Volume    52 
70Author    J. Dolinšek, G. Lahajnar, B. Marin, J. Pirš, A. Sepe, J. Slak, F. Milia, R. BlincRequires cookie*
 Title    Temperature Dependence of the Proton NMR Spectra of Bitumen  
 Abstract    The temperature dependence of the proton NMR spectra of bitumen samples of different origin and quality has been measured between 400 K and 80 K. Whereas the linewidths of different samples are essentially identical above 340 K and below 240 K, there is a significant difference in the linewidth transition region around room temperature. The results show that it is possible to discriminate between bitumen samples of different composition and quality by simply measuring the proton NMR linewidth at room tem-perature. 
  Reference    Z. Naturforsch. 52a, 373—375 (1997); received December 7 1996 
  Published    1997 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0373_n.pdf 
 Identifier    ZNA-1997-52a-0373_n 
 Volume    52 
71Author    P. Stifter, C. Leichtie, W. P. Schleich, J. MarklofRequires cookie*
 Title    Das Teilchen im Kasten: Strukturen in der Wahrscheinlichkeitsdichte The Particle in a Box: Structures in the Probability Density  
  Reference    Z. Naturforsch. 52a, 377—385 (1997); eingegangen am 28. Januar 1997 
  Published    1997 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0377.pdf 
 Identifier    ZNA-1997-52a-0377 
 Volume    52 
72Author    Thomas Wieder, Hartmut FuessRequires cookie*
 Title    A Generalized Debye Scattering Equation  
 Abstract    The Debye scattering equation for amorphous material and the Laue scattering equation for crys-talline material follow from different assumptions on the orientation distribution of the interatomic distance vector A generalization of these assumptions leads to a new scattering equation which is presented here. 1. Theory Consider the interatomic distance vector r 
  Reference    Z. Naturforsch. 52a, 386—392 (1997); received January 27 1997 
  Published    1997 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0386.pdf 
 Identifier    ZNA-1997-52a-0386 
 Volume    52 
73Author    Ruedi StoopRequires cookie*
 Title    Fingerprints of Superpositions of Multifractals and Second Order Phase Transitions  
 Abstract    The generic model of superimposed multifractal measures is discussed from the generalized entropy point of view. Natural conditions for the existence of second order critical lines are given. The second order phase transitions may manifest themselves in stopping points of the entropy-like thermodynamic functions. The findings are of experimental relevance. 
  Reference    Z. Naturforsch. 52a, 393—397 (1997); received December 19 1996 
  Published    1997 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0393.pdf 
 Identifier    ZNA-1997-52a-0393 
 Volume    52 
74Author    D. Sen, A. N. Basu, S. SenguptaRequires cookie*
 Title    Is the Uncertainty Relation at the Root of all Mutual Exclusiveness?  
 Abstract    It is argued that two distinct types of complementarity are implied in Bohr's complementarity principle. While in the case of complementary variables it is the quantum mechanical uncertainty relation which is at work, the collapse hypothesis ensures this exclusiveness in the so-called wave-particle complementarity experiments. In particular it is shown that the conventional analysis of the double slit experiment which invokes the uncertainty principle to explain the absence of the simul-taneous knowledge of the which-slit information and the interference pattern is incorrect and implies consequences that are quantum mechanically inconsistent. 
  Reference    Z. Naturforsch. 52a, 398—402 (1997); received October 10 1994 
  Published    1997 
  Keywords    Bohr's Complementarity Principle, Wave-Particle Duality, Uncertainty Relation, Mu-tual Exclusiveness, Quantum Mechanics 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0398.pdf 
 Identifier    ZNA-1997-52a-0398 
 Volume    52 
75Author    S. Urban, H. Kresse, R. DąbrowskiRequires cookie*
 Title    Low Frequency Dielectric Relaxation Process in Liquid Crystals with Nematic and Liquid-Like Smectic Phases  
 Abstract    Results of dielectric studies of the low frequency relaxation process in several substances exhibiting nematic -smectic C polymorphism are presented. They are compared with the data obtained re-cently for substances with nematic-smectic A and nematic-smectic B phase sequences. It was found that the rate of molecular reorientation around the short axes does not change at the transition between the nematic and a liquid-like smectic phase (Sm A, Sm C), whereas it is considerably retarded at that of the nematic-solid-like smectic (Sm B) phase. However, the activation barrier for this motion is markedly lower in the orthogonal smectics (Sm A, Sm B) than in the nematic and Sm C phases. The analysis of numerous experimental data on the activation enthalpy in the nematic phase shows that the Arrhenius equation conforms better with results than the Diogo-Martins approach, if the nematic range exceeds 10 K. 
  Reference    Z. Naturforsch. 52a, 403—408 (1997); received February 17 1997 
  Published    1997 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0403.pdf 
 Identifier    ZNA-1997-52a-0403 
 Volume    52 
76Author    A. Kawski, G. PiszczekRequires cookie*
 Title    Absorption, Fluorescence and Emission Anisotropy Spectra of 4-Cyano-N,N-dimethylaniline in Different Media and at Different Temperatures  
 Abstract    The effect of temperature on fluorescence and emission anisotropy spectra of 4-cyano-N,N-dimethylaniline (CDMA) was investigated in viscous (glycerol and paraffin oil) and rigid (polyvinyl alcohol) PVA and polyvinyl chloride) PVC) media. A strong effect of temperature on the intensity of a and b emission bands was observed. It was also found that the emission anisotropy, r, does not vary in the longwave emission band a at a fixed temperature but decreases in the emission band b together with the decreasing wavelength. The latter effect is due to the fact that the transition moment in this band is perpendicular to the long axis of the CDMA molecule. For CDMA in paraffin oil, a normal b band with negative emission anisotropy only occurs. In all other media used, the emission anisotropy has lower values, approaching zero, which results from the considerable covering of band b with a broad emission band a. 
  Reference    Z. Naturforsch. 52a, 409—414 (1997); received March 3 1997 
  Published    1997 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0409.pdf 
 Identifier    ZNA-1997-52a-0409 
 Volume    52 
77Author    B. Sedelmeyer, S. SteebRequires cookie*
 Title    Structure of Fe-Si-melts by X-ray Diffraction  
 Abstract    X-ray diffraction was done with molten Fe 66 7 Si 33 3 and molten Fe 33 3 Si 66 7 . The coordination numbers versus the concentration lie above the connection line between the coordination numbers of the unalloyed molten elements Fe and Si, respectively, which means a tendency for microsegrega-tion. The pair correlation function of molten Fe 66 7 Si 33 3 was modeled using the data of crystalline Fe 2 Si. At the same time, the pair correlation function of the molten alloy Fe 33 3 Si 66 7 can be modeled using the data of the corresponding crystalline alloy. Thus for molten Fe 33 3 Si 66 7 microsegregation into FeSi 2 and Si or FeSi and for molten Fe 66 7 Si 33 3 microsegregation into Fe 2 Si and Fe or FeSi exists. 
  Reference    Z. Naturforsch. 52a, 415—419 (1997); received February 26 1997 
  Published    1997 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0415.pdf 
 Identifier    ZNA-1997-52a-0415 
 Volume    52 
78Author    A. A. Red 'kin, A. B. Salyulev, M. V. Smirnov, V. A. KhokhlovRequires cookie*
 Title    Density and Electrical Conductivity of Molten (2K, Fe)Cl 2 , (2K, Co)Cl 2 , and (2K, Ni)Cl 2  
 Abstract    The density and electrical conductivity of molten (2 K, Fe) Cl 2 , (2 K, Co) Cl 2 and (2 K, Ni) Cl 2 have been investigated. The density was measured by the maximum bubble pressure and dylatometric methods, the electrical conductivity by an AC technique. The molar volume and equivalent conduc-tance were calculated. 
  Reference    Z. Naturforsch. 52a, 420—424 (1997); received October 25 1996 
  Published    1997 
  Keywords    Molten chlorides, Density, Electrical conductivity 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0420.pdf 
 Identifier    ZNA-1997-52a-0420 
 Volume    52 
79Author    Christian Gebauer, Olaf Klein, Ralf Schmidt, Wolfhart SeidelRequires cookie*
 Title    Helium Atom Scattering from Cyclopentane, Pyrrolidine and Tetrahydrofurane in Crossed Molecular Beams  
 Abstract    Scattering of helium atoms by cyclopentane, pyrrolidine and tetrahydrofurane molecules was ob-served in crossed molecular beam experiments. The intensity of scattered helium atoms, depending on the scattering angle, was measured with high resolution, and the damping of the diffraction oscil-lations of the differential cross sections was used to extract elastic anisotropic interaction potentials for these molecules. The evaluation included a geometric transformation concerning the puckered states of the envelope and the twisted conformation of the molecules. The potentials were found to be rather similar. 
  Reference    Z. Naturforsch. 52a, 425—431 (1997); received February 27 1997 
  Published    1997 
  Keywords    Molecular beams, helium, saturated 5-rings, interaction potentials, ring puckering 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0425.pdf 
 Identifier    ZNA-1997-52a-0425 
 Volume    52 
80Author    Axel Kohlmeyer, Wolfgang Witschel, Eckhard SpohrRequires cookie*
 Title    Long-range Structures in Bulk Water. A Molecular Dynamics Study  
 Abstract    We present recent calculations of pair correlation functions and partial structure factors derived from molecular dynamics simulations of large bulk water systems (up to 12 167 water molecules). We observe small amplitude oscillations of the pair correlation functions in the range between 10 and 20 Ä. 
  Reference    Z. Naturforsch. 52a, 432—434 (1997); received March 7 1997 
  Published    1997 
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 TEI-XML for    default:Reihe_A/52/ZNA-1997-52a-0432.pdf 
 Identifier    ZNA-1997-52a-0432 
 Volume    52 
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