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1994[X]
161Author    Jun Chen, Mao-Lu, Zhao-Ming LiRequires cookie*
 Title    Jia  
 Abstract    This paper presents a cluster approach to the zero-field splitting (ZFS) of the ground state 3A2(F) of d8 ions with tetragonal symmetry, in which not only the spin-orbit coupling of the central transition-metal-ion but also that of ligands contributes. For some pseudo-tetragonal Ni(II) com­ pounds the calculated values of the ZFS parameter follow the order Cl -> Br-> I -. This agrees with the experimental finding, while the pure crystal field approach considering only the coupling of central metal ion yields the opposite trend. 
  Reference    Z. Naturforsch. 49a, 1013—1015 (1994); received July 28 1994 
  Published    1994 
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 Identifier    ZNA-1994-49a-1013 
 Volume    49 
162Author    O., Manfred HolzRequires cookie*
 Title    Xi-an M a  
 Abstract    The 14N quadrupole relaxation time in pure D M F is by 9% longer than in pure DMF-d7, showing the dependence of the reorientational molecular motion on the square root of the moment of inertia. But for traces of DM F and DMF-d7 in DMSO, the 14N quadrupole relaxation time tends to obey the "square-root-of-the-reduced-mass law", as expected from the kinetic theory of dense fluids. The vanishing of the moment-of-inertia effect on the intramolecular nuclear quadrupole relaxation is discussed in terms of molecular translation-rotation coupling. 
  Reference    Z. Naturforsch. 49a, 1016—1018 (1994); received 
  Published    1994 
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 Identifier    ZNA-1994-49a-1016 
 Volume    49 
163Author    Van Der LugtRequires cookie*
 Title     
 Abstract    Dedicated to Professor Hans-Uwe Schuster on the occasion of his 65th birthday Recent measurements of the electrical resistivity of liquid Li-Ge alloys enable us to check relations between N M R properties and resistivity in non-metallic alloys derived by Warren in 1971. It is shown that the predicted linear relationships hold, but that the proportionality between the square root of the conductivity and the Knight shift is violated to some degree. A possible cause is the neglect of quadrupole interactions. Also, the relations only hold if the composition rather than the temperature is taken as the implicit parameter. 
  Reference    Z. Naturforsch. 49a, 1019—1022 (1994); received May 4 1994 
  Published    1994 
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 Identifier    ZNA-1994-49a-1019 
 Volume    49 
164Author    F. WinterbergRequires cookie*
 Title      
 Abstract    It is shown that the Bekenstein-Hawking formula for the entropy of a black hole can be given a statistical mechanical interpretation in terms of Planck mass particles. It is furthermore shown that the previously proposed Planck aether model (assuming that space is densely filled with an equal number of positive and negative Planck masses) gives an expression for the black hole entropy, different from the Bekenstein-Hawking formula, with the entropy proportional to the 3/4 power of the black hole surface rather than proportional to its surface. The Planck aether model also gives an expression for the entropy of the gravitational field, which for a black hole is the entropy of negative Planck masses. To be consistent with Nernst's theorem, it is conjectured that this gravitational field entropy is negative. For a universe in which the sum of the positive matter energy and the negative gravitational field energy is zero, the sum of the matter and gravitational field entropy would therefore vanish as well. Because the positive and negative Planck masses are separated from each other, a cancellation of their entropy appears to be only possible in the event of a gravitational collapse of the universe as a whole. 
  Reference    Z. Naturforsch. 49a, 1023—1030 (1994); received October 6 1993 
  Published    1994 
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 Identifier    ZNA-1994-49a-1023 
 Volume    49 
165Author    Masatoshi Saito1, Makoto Wakeshima1, Nobuaki Sato1, Takeo Fujino1, Yoshio Waseda, Eiichiro Matsubara2, K.Thomas Jacob3Requires cookie*
 Title      
 Abstract    Anomalous X-ray scattering (AXS) has been applied to study the structure of amorphous plati­ num disulfide, Pt1_;cS2, prepared by the precipitation process. The local atomic arrangement in amorphous Pt: _XS2 was determined by the least-squares variational method so as to reproduce the experimental differential interference function at the Pt Lin absorption edge by the AXS method as well as the ordinary interference function by Mo Ka. The structural unit in amorphous Ptj-^Sj is found to be a PtS6 octahedron, similar to that in crystalline PtS2. These octahedra share both their corners and edges, while only edge-sharing linkages 
  Reference    Z. Naturforsch. 49a, 1031—1036 (1994); received September 13 1994 
  Published    1994 
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 Identifier    ZNA-1994-49a-1031 
 Volume    49 
166Author    H. DanielRequires cookie*
 Title      
 Abstract    The Concept of a Novel Heat Engine The concept of a novel heat engine based on Knudsen-thermotransport of gas is outlined. The conversion factor is calculated. For small temperature differences its theoretical value amounts to half the Carnot value. The novel engine may turn out to be particularly suitable for using solar energy. 
  Reference    Z. Naturforsch. 49a, 1037—1039 (1994); received October 31 1994 
  Published    1994 
  Keywords    Heat engine, Thermotransport, Porous plug, Energy conversion, Solar energy 
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 Identifier    ZNA-1994-49a-1037 
 Volume    49 
167Author    IvanG. Utm Anab, GyulaD. ÖmRequires cookie*
 Title      
 Abstract    It is shown that the values which the Wiener numbers of isomeric polyphenyls may assume are all congruent modulo 36. Similarly, the Wiener numbers of isomeric phenylens are always congruent modulo 18. These findings provide a rationalization for the known fact that the isomer-discriminat­ ing power of the Wiener number is rather weak. Extensions of the present results to more general classes of graphs are also pointed out. 
  Reference    Z. Naturforsch. 49a, 1040—1044 (1994); received September 26 1994 
  Published    1994 
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 Identifier    ZNA-1994-49a-1040 
 Volume    49 
168Author    A. I. Melker, T. V. VorobyevaRequires cookie*
 Title    Polymer Crystallization as the Self-Organization of Chain Macromolecules  
 Abstract    M D simulation is used to investigate ther self-organization exhibited by a chain o f atom s with strong interaction between nearest neighbours and weak interaction between more distant atoms. It is shown that the supermolecular structure is formed in several steps: at first, an initially straight chain becom es zigzag-shaped, then the zigzag ribbon folds, producing regions of crystalline and amorphous structure; after that the system contracts into a globe, the amorphous-structure regions transforming into crystalline ones by a reptile like motion. A simple analytical description of such polymer structuring is also given. 
  Reference    Z. Naturforsch. 49a, 1045—1052 (1994); received July 22 1994 
  Published    1994 
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 Identifier    ZNA-1994-49a-1045 
 Volume    49 
169Author    Tm An, Y.-N Yehb, S.-LL. Eec, H. H. Osoyad, S.J C Yvin£Requires cookie*
 Title     
 Abstract    The determinant of the adjacentcy matrix, the algebraic structure count and the Kekule structure count of circulenes are shown to conform to simple expressions containing Fibonacci numbers. 
  Reference    Z. Naturforsch. 49a, 1053—1058 (1994); received April 12 1994 
  Published    1994 
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 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-1053.pdf 
 Identifier    ZNA-1994-49a-1053 
 Volume    49 
170Author    J. G. Ripp, U. K. Retschm Er, H. DreizlerRequires cookie*
 Title    The 33S Nuclear Hyperfine Structure in the Rotational Spectrum of Isothiazole  
 Abstract    We investigated the 33S nuclear quadrupole coupling in the rotational spectrum of isothiazole in natural abundance by molecular beam Fourier transform microwave spectroscopy. In addition the 14N nuclear quadrupole coupling could be analyzed with high precision. We derived the rotational constants A = 8275.51880(80) MHz, B = 5767.06181 (40) MHz, and C = 3396.85702(36) MHz, quartic centrifugal distortion constants, and the quadrupole coupling constants xaa (33S) = 8.7015 (57) MHz, Xbb(33S) = -3 2 .9 6 9 6 (6 0) MHz, *aa(14N) = 1.0732(47) M H z and *bfc(14N) = -2 .4 7 5 3 (4 6) MHz. 
  Reference    Z. Naturforsch. 49a, 1059—1062 (1994); received Novem ber 15 1994 
  Published    1994 
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 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-1059.pdf 
 Identifier    ZNA-1994-49a-1059 
 Volume    49 
171Author    S. R. Huber, A. Bauder, V. Storm, H. DreizierRequires cookie*
 Title    Reanalysis of the Nuclear Quadrupole Coupling in the Rotational Spectrum of N-Methylpyrrole  
 Abstract    The rotational spectrum o f N-m ethylpyrrole has been measured with pulsed nozzle Fourier transform m icrowave spectrometers betw een 6 and 38 G H z. The quadrupole hyperfine structure due to 14N has been reanalyzed in the A (m = 0) state o f the methyl internal rotation. Improved rotational constants, centrifugal distortion constants, and quadrupole coupling constants have been sim ultaneously determ ined from the measured transition frequencies in an iterative least-squares fit. 
  Reference    Z. Naturforsch. 49a, 1063 (1994); received Septem ber 17 1994 
  Published    1994 
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 Identifier    ZNA-1994-49a-1063 
 Volume    49 
172Author    A. G. Oldbach1, F. H. Ensel1, K. R. Ad, Em An NRequires cookie*
 Title    Size-dependent Trends in the Scattering of Small Potassium Clusters by Water Molecules  
 Abstract    Scattering o f small potassium clusters by water molecules has been studied in a molecular beam experiment for the first time. In the size range up to eight atom s, trends for cross sections have been obtained by investigating low energy collisions. Significant differences in relative cross sections can be assigned to inelastic collisions. As in case o f scattering o f sodium clusters by argon (Goerke, A. et al., J. Chem. Phys. 98, 9653 (1993)), rotational excitation o f the clusters seems to be the dominating interaction. 
  Reference    Z. Naturforsch. 49a, 1067—1073 (1994); received September 28 1994 
  Published    1994 
  Keywords    Potassium clusters, Inelastic scattering, M olecular beam, Mass spectrometry, P hoto­ ionization 
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 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-1067.pdf 
 Identifier    ZNA-1994-49a-1067 
 Volume    49 
173Author    Vladimir SimulikRequires cookie*
 Title    Some Algebraic Properties of Maxwell-Dirac Isomorphism  
 Abstract    A new derivation of the M axw ell-D irac isom orphism is presented. A complete set of transforma­ tions connecting M axwell's electrodynam ics and wave mechanics is obtained. 
  Reference    Z. Naturforsch. 49a, 1074 (1994); received September 23 1994 
  Published    1994 
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 Identifier    ZNA-1994-49a-1074 
 Volume    49 
174Author    J. Jadży, L. H. Ellem, M. Stockhausen3, C. Legrand4, G. Czechowski1Requires cookie*
 Title    Dielectric Relaxation in Nematic and Isotropic Phases of 4-(f#*a/is-4'-n-Propylcy clohexyl) iso thiocyana to benzene  
 Abstract    The results o f a dielectric relaxation study (in the frequency region from about 1 kHz to 1 G Hz) of the liquid crystalline title com pound (C 3H 7-C y h x -P h -N C S , 3-CHBT) in the isotropic and the nematic phase (measurements with electric field parallel to alignment) are presented. The spectra of both phases can be described by two relaxation processes of Debye-type, possibly related to rotation around the long and short molecular axes. 
  Reference    Z. Naturforsch. 49a, 1077 (1994); received September 24 1994 
  Published    1994 
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 Identifier    ZNA-1994-49a-1077 
 Volume    49 
175Author    I. D. Ierking1, F. G. Ießelm Ann1, P. Zugenm, H. R2, H. Z. Aschke2, W. Kuczynski3Requires cookie*
 Title    The Origin of the Helical Twist Inversion in Single Component Cholesteric Liquid Crystals  
 Abstract    The cholesteric twist inversion by temperature variation o f a single com ponent thermotropic liquid crystalline system was experimentally investigated and is explained by the partial twisting power model, evaluating the temperature dependent pitch o f five different configurations of a benzoic acid biphenyl ester with two chiral centers. The temperature dependence o f the twisting power and the cholesteric pitch for several stereoisomeric com pounds can in first approximation be predicted by the partial twisting powers of the individual chiral centers determined from the partially racemic configurations. 
  Reference    Z. Naturforsch. 49a, 1081—1086 (1994); received August 12 1994 
  Published    1994 
  Keywords    Liquid crystal, Chirality, Cholesteric mesophase, Twist inversion 
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 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-1081.pdf 
 Identifier    ZNA-1994-49a-1081 
 Volume    49 
176Author    S.H H Üttenhain, W. Balzer, R. FeldmRequires cookie*
 Title    Fluorescence of 8-(Phenylamino)-l-naphthalene-ammonium- sulfonate in Solvents of Different Polarity  
 Abstract    The solvatochrom ic fluorescence properties of 8-(phenylam ino)-l-naphthalene-am m onium sulfo-nate (1) were investigated in 22 pure solvents of rising polarity. The measurements o f both Stokes' shifts and intensities discriminated between protic and aprotic solvents. Fairly good linear correla­ tion plots of the dependence could be obtained on neglection of the values o f tert.-butanol, D M F and DM SO . Key words: Solvatochrom ic fluorescence; 8-(Phenylam ino)-l-naphthalene-sulfonate (8,1 A N S); Protic solvents; Aprotic solvents. 
  Reference    Z. Naturforsch. 49a, 1087 (1994); received M ay 31 1994 
  Published    1994 
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 Identifier    ZNA-1994-49a-1087 
 Volume    49 
177Author    A. K. Aw Skia, I. Gryczyń Sk Ib, Z. Gryczyń, Sk IbRequires cookie*
 Title    Fluorescence and Phosphorescence Anisotropy Spectra o f Indole in P oly (V inyl A lcohol) Film at Room Temperature  
 Abstract    Excitation anisotropy spectra of indole were measured in poly (vinyl alcohol) film at room temperature. The behaviour of the phosphorescence anisotropy o f indole in isotropic and anisotropic PVA film enabled a conclusion to be drawn that the Tj — S0 transition is located outside the indole ring plane, close to the perpendicular direction. 
  Reference    Z. Naturforsch. 49a, 1091 (1994); received O ctober 11 1994 
  Published    1994 
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 Identifier    ZNA-1994-49a-1091_n 
 Volume    49 
178Author    G. GrimmRequires cookie*
 Title    Effective Gauge Theories with Symmetry Breaking  
 Abstract    In a previous paper a general group theoretical discussion of effective boson-fermion coupling theories (with com posite two-fermion bosons) resulting by weak m apping of nonlinear spinor-isospinor field models was given. In the present work these considerations are extended to the case of broken isospin symmetry and applied to a m icroscopic subfermion-description of phenom enolog­ ical gauge theories with Higgs symmetry breaking. PACS 11.10 -Field theory. PACS 12.10 -Unified field theories and models. PACS 12.35 -Com posite m odels of particles. 
  Reference    Z. Naturforsch. 49a, 1093—1101 (1994); received August 26 1994 
  Published    1994 
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 Identifier    ZNA-1994-49a-1093 
 Volume    49 
179Author    R. K. Sanghvi, R. K. ChhajlaniRequires cookie*
 Title    Hydromagnetic Kelvin-Heimholtz Instability in the Presence of Suspended Particles and Finite Larmor Radius Effect  
 Abstract    A linear analysis o f the com bined influence of a finite ion Larmor radius and suspended particles on K elvin-H elm holtz instability in the presence of a uniform magnetic field is carried out. The magnetic field is assumed to be uniform and transverse to the direction of streaming. The medium is assumed to be incompressible. Certain simplifying assumptions are made for the m otion of the suspended particles. A dispersion relation for such a medium has been obtained using appropriate boundary conditions. The stabilizing effect of a finite Larmor radius has been reasserted in the absence of the suspended particles. A stability criterion for the medium is derived, which is found to be independent o f the presence of the suspended particles. Similarly a condition of instability of the system is also derived. Num erical analysis is presented in a few limiting cases of interest. Furthermore, growth rates of unstable modes of the configuration with increasing relaxation fre­ quency of the particles and finite Larmor radius have been evaluated analytically. It is shown that the finite Larmor radius in the presence o f the suspended particles destabilizes a certain wave number band which is stable otherwise. Implications of the suspended particles on the growth rate of unstable modes are discussed in the limit of vanishing ion Larmor radius. 
  Reference    Z. Naturforsch. 49a, 1102 (1994); received September 28 1994 
  Published    1994 
  Keywords    Plasma instability, M agnetohydrodynam ic instability, Suspended particles, Kelvin-H elm holtz instability, Finite Larmor radius effect 
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 Identifier    ZNA-1994-49a-1102 
 Volume    49 
180Author    AxelH. Saleck1, M. Artin Liedtke, Alexandra Dolgner, Gisbert WinnewisserRequires cookie*
 Title      
 Abstract    The mm-wave spectra of 15N l s O and 14N 170 in both X 2n l/2 and Ar2/73/2 states have been measured and assigned for the first time. Improved rotational and, for the first time, 170 hyperfine coupling constants have been derived from the analysis. The 14N lvO data yield parameters o f the unpaired electron spatial distribution near both nuclei. Furthermore, the deviation from the Born-Oppenheim er approximation is confirmed on the basis of the rotational constants of five isoto-pomers. Finally, when comparing the nuclear spin-rotation constants to the ones o f other molecules containing 14N or 170 nuclei, a roughly linear proportionality with the rotational constant B is found. 
  Reference    Z. Naturforsch. 49a, 1111—1118 (1994); received September 16 1994 
  Published    1994 
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 TEI-XML for    default:Reihe_A/49/ZNA-1994-49a-1111.pdf 
 Identifier    ZNA-1994-49a-1111 
 Volume    49 
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