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1999[X]
21Author    C. Bessada, V. Lacassagne, D. Massiot, P. Florian, J.-P Coutures, E. Robert, B. GilbertRequires cookie*
 Title    Structural and Dynamic Approaches of Molten Salts by High Temperature Spectroscopies  
 Abstract    The combination of 27 AI NMR expriments and Molecular Dynamics simulation confirms the exis-tence of penta-coordinated Aluminium in several molten aluminium oxides. In the case of fluoroalumi-nate molten salts, NMR and Raman spectroscopies provide complementary approaches leading to a structural description in term of AIF4, AlF 2-and AlF^f species. 
  Reference    Z. Naturforsch. 54a, 162—166 (1999); received November 27 1998 
  Published    1999 
  Keywords    27 A1 High Temperature NMR, Oxides, NaF-AlF 3 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0162.pdf 
 Identifier    ZNA-1999-54a-0162 
 Volume    54 
22Author    Rui-Hua Xie, Paul BrumerRequires cookie*
 Title    Quantum Reflection of Ultracold Atoms in Magnetic Traps  
 Abstract    Ultracold neutral atoms can be trapped in spatially inhomogeneous magnetic fields. In this paper, we present a theoretical model and demonstrate by using Landau-Zener tool that if the magnetic resonant transition region is very narrow, "potential barriers" appear and quantum reflection of such ultracold atoms can be observed in this region. 
  Reference    Z. Naturforsch. 54a, 167—170 (1999); received February 26 1999 
  Published    1999 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0167.pdf 
 Identifier    ZNA-1999-54a-0167 
 Volume    54 
23Author    Rui-Hua Xie, Paul BrumerRequires cookie*
 Title    Coherent Control Theory of off Resonance Refractive Index of Medium with a Gaussian Pulse of Coherent Light  
 Abstract    In this paper we develop a coherent control theory of the off resonance refractive index of a medium with a Gaussian pulse of coherent light. The refractive index of gaseous Ni is studied by using this theory. It is found that the off resonance refractive index of gaseous N2 can be enhanced through the coherent control approach by changing the coherent parameters or the pulse duration of the coherent light. 
  Reference    Z. Naturforsch. 54a, 171—176 (1999); received March 4 1999 
  Published    1999 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0171.pdf 
 Identifier    ZNA-1999-54a-0171 
 Volume    54 
24Author    F. Köksal, İ. Kartal, B. KarabulutRequires cookie*
 Title    Electron Paramagnetic Resonance of Cu 2+ in KHC0 3 Single Crystals  
 Abstract    The electron paramagnetic resonance spectra of Cu 2+ doped KHC0 3 single crystals were studied at room temperature. The results indicate a substitutional entrance of the Cu 2+ ions in place of the magnetically inequivalent K + sites. The charge compensation is supposed to be fulfilled by proton vacancies. The hyperfine lines were well resolved and the 65 Cu hyperfine coupling tensors were also found. The ground state of Cu 2+ indicates the dominance of the d x i_ y 2 orbital and, therefore, elongation of the polyhedron, similar to a lengthened octahedron. 
  Reference    Z. Naturforsch. 54a, 177—179 (1999); received January 9 1999 
  Published    1999 
  Keywords    EPR, Cu 2+, Potassium Bicarbonate, Crystal Field, Substitution, Impurity 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0177.pdf 
 Identifier    ZNA-1999-54a-0177 
 Volume    54 
25Author    Z. Akdeniz, M. P. TosiRequires cookie*
 Title    A Refined Ionic Model for Clusters Relevant to Molten Chloroaluminates  
 Abstract    A model of ionic interactions in neutral and ionized aluminium trichloride clusters, which accounts for ionic deformability through (i) effective valences and (ii) electrostatic and overlap polarizabilities, is evaluated for applications to classical simulation studies of the pure melt and of molten alkali chloroaluminates. The disposable parameters in the model are determined from the measured values of the bond length in the (A1C1 4)~ molecular ion and of an Al-Cl bond length and a vibrational frequency in the A1 2 C1 6 molecular dimer. The model is tested against the remaining available data from experiment and from quantum chemical calculations on molecular bond lengths, bond angles and vibrational frequencies for A1 2 C1 6 , (A1C1 4)~ and (A1 2 C1 7)~ clusters. Structural and dynamical properties are also evaluated for the (A1 2 C1 5) + , A1C1 3 and (A1C1 2) + clusters. The results for the energetics of dissociation, ion transfer and isomer excitation reactions are compared with as yet unpublished data obtained by P. Ballone in first-principles calculations by a density functional method. The overall quality of the tests supports the approximate validity and transferability of the model. 
  Reference    Z. Naturforsch. 54a, 180—186 (1999); received February 17 1999 
  Published    1999 
  Keywords    Ionic Clusters, Liquid Structure, Molten Salts 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0180.pdf 
 Identifier    ZNA-1999-54a-0180 
 Volume    54 
26Author    H. Klein, E. Klisch, G. Winnewisser, A. Königshofen, J. HahnRequires cookie*
 Title    CP's Triple-bond Strength Experienced in its THz Spectrum  
 Abstract    The submillimeter-wave rotational spectrum of the CP radical in the electronic and vibrational ground state (X 2 Z +) was recorded in the frequency region between 572 GHz and 1.05 THz, covering rotational quantum numbers from N = 11 up to 21. The CP radical has been produced by discharging CH4 over red phosphorus buffered with Ar at liquid nitrogen temperature. Analysis of the new rotational data of CP together with those available in the literature allows the derivation of an accurate set of molecular constants, including rotational, BQ = 23859.91521(28) MHz and the centrifugal distortion constant Do = 39.8140(19) kHz, the fine structure and hyperfine structure parameters. The stiffness of the CP bond can be inferred by requiring only one distortion constant Do to fit the measured rotational spectrum. 
  Reference    Z. Naturforsch. 54a, 187—190 (1999); received January 19 1999 
  Published    1999 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0187.pdf 
 Identifier    ZNA-1999-54a-0187 
 Volume    54 
27Author    B. Pranszke, P. Kierzkowski, A. KowalskiRequires cookie*
 Title    A Search for Isotope Effects in Chemiluminescent Reactions of Metastable Ca*( 3 Pj, *D 2 ) Atoms with CH 3 I and CD 3 I Molecules  
 Abstract    Chemiluminescent reactions of calcium atoms in the metastable Pj and 'D, states with CH 3 I and CD 3 I were studied in a beam-gas arrangement. Calcium monoiodide spectra associated with transitions from the electronic A IT, B 2 Z + and C 2 n states to the X 2 L + ground state were recorded. Total collision and chemiluminescence cross sections were measured. It was found that isotopic substitution in the methyl group does not change the reaction cross sections and the chemiluminescence spectra. 
  Reference    Z. Naturforsch. 54a, 191—194 (1999); received February 2 1999 
  Published    1999 
  Keywords    Chemiluminescence, Energy Transfer, Atomic Collisions, Molecular Collisions, Isotopic Effect 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0191.pdf 
 Identifier    ZNA-1999-54a-0191 
 Volume    54 
28Author    Jian-Song Yang, Sen-Yue LouRequires cookie*
 Title    Solitary Wave Solutions of High Order Scalar Fields and Coupled Scalar Fields  
 Abstract    An arbitrary Klein-Gordon field with a quite general constrained condition (which contains an arbitrary function) can be used as an auxilialy field such that some special types of solutions of high order scalar fields can be obtain by solving an ordinary differential equation (ODE). For a special type of constraint, the general solution of the ODE can be obtained by twice integrating. The solitary wave solutions of the model are treated in an alternative simple way. The obtained solutions of the model can be changed to those of the 0 8 field and coupled scalar fields. 
  Reference    Z. Naturforsch. 54a, 195—203 (1999); received December 13 1998 
  Published    1999 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0195.pdf 
 Identifier    ZNA-1999-54a-0195 
 Volume    54 
29Author    J. Choy, K. L. Liu, C. F. Lo, F. SoRequires cookie*
 Title    Thermodynamic Properties of Bosons in Symmetric Double-well Potentials  
 Abstract    We study the thermodynamic properties and the Bose-Einstein condensation (BEC) for a finite num-ber N of identical non-interacting bosons in the field of a deep symmetric double-well potential (SDWP). The temperature dependence of the heat capacity C(T) at low temperatures is analyzed, and we derive several generic results which are valid when the energy difference between the first two excited states is sufficiently large. We also investigate numerically the properties of non-interacting bosons in three-dimensional superpositions of deep quartic SDWP's. At low temperatures, we find that C(T) displays microstructures which are sensitive to the value of N and the thermal variation of the condensate frac-tion shows a characteristic plateau. The origin of these features is discussed, and some general conclu-sions are drawn. PACS numbers: 03.75.Fi, 05.30.Jp 
  Reference    Z. Naturforsch. 54a, 204—212 (1999); received December 7 1998 
  Published    1999 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0204.pdf 
 Identifier    ZNA-1999-54a-0204 
 Volume    54 
30Author    S. Kassi, H. DreizlerRequires cookie*
 Title      
 Abstract    We present a general consideration how many structural conformers are compatible with one set of rotational constants if one rotational spectrum of a dimer is investigated. A selection of a certain con-former should be guided by the investigation of isotopomers, quantum chemical calculations or other arguments. 
  Reference    Z. Naturforsch. 54a, 213—217 (1999); received December 16 1998 
  Published    1999 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0213.pdf 
 Identifier    ZNA-1999-54a-0213 
 Volume    54 
31Author    N. Nissen, J. Doose, A. Guarnieri, H. Mäder, V. N. Markov, G. Yu, Golubyatnikov, 1. Leonov, V. N. Shanin, A. F. KrupnovRequires cookie*
 Title    Foreign Gas Broadening Studies of the J' <-J = 1 0 Rotational Line of CO by Frequency and Time Domain Techniques  
 Abstract    The collisional broadening of the J' J = 1 <— 0 rotational line of carbon monoxide by the buffer gases He, Ne, Ar, Kr, CO, N 2 , 0 2 , and air has been studied at room temperature. Two different experimental techniques in time-and frequency-domain, respectively, were used. The obtained data are in good agreement. Time-domain investigations on the temperature dependence of the foreign gas broadening parameters are also presented. 
  Reference    Z. Naturforsch. 54a, 218—224 (1999); received December 14 1998 
  Published    1999 
  Keywords    CO, Line Broadening, Buffer Gases, Temperature Dependence 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0218.pdf 
 Identifier    ZNA-1999-54a-0218 
 Volume    54 
32Author    E. Mikuli, A. Migdał-Mikuli, S. WróbelRequires cookie*
 Title    Phase Transitions in Crystalline [Me(H 2 0) 6 ](BF 4 ) 2 . Part I (Me = Mn, Fe, Co, Ni and Zn)  
 Abstract    Solid polymorphism in five compounds of the type [Me(H 2 0) 6 ](BF 4) 2 , where Me = Mn, Fe, Co, Ni and Zn, have been studied in the temperature range 120 -330 K by DSC. For each substance at least three solid modifications have been found. In addition, for compounds with Me = Mn, Fe and Zn some new low temperature phase transitions have been observed. The transition temperatures for the [Me(H 2 0) 6 ](BF 4) 2 compounds are distinctly lower than those for the [Me(H 2 0) 6 ](C10 4) 2 compounds. The entropy-and enthalpy-changes at the phase transitions of the hexaaquametal(II) tetrafluoroborates are significantly lower than those for the corresponding chlorates(VII). Linear correlations between the highest transition temperature and the crystal density are found for both series of these isomorphous compounds. 
  Reference    Z. Naturforsch. 54a, 225—228 (1999); received December 12 1998 
  Published    1999 
  Keywords    Hexaaquametal(II) tetrafluoroborates, Phase Transitions, DSC Method 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0225.pdf 
 Identifier    ZNA-1999-54a-0225 
 Volume    54 
33Author    M. Gaune-Escard, L. RycerzRequires cookie*
 Title    Heat Capacity of K 3 LnCl 6 Compounds with Ln = La, Ce, Pr, Nd  
 Abstract    The heat capacities of the solid and liquid K 3 LnCl 6 compounds (Ln = La, Ce, Pr, Nd) have been determined by differential scanning calorimetry (DSC) in the temperature range 300 -1100 K. Their temperature dependence is discussed in terms of the phase transitions of these compounds as reported in literature. The heat capacity increases and decreases strongly in the vicinity of a phase transition but else varies smoothly. The C p data were fitted by an equation which provides a satisfactory representation up to the temperatures of C p discontinuity. The measured heat capacities were checked for consistency by calculating the enthalpy of formation of the liquid phase, which had been previously measured. The results obtained compare satisfactorily with these experimental data. 
  Reference    Z. Naturforsch. 54a, 229—235 (1999); received December 17 1998 
  Published    1999 
  Keywords    Lanthanum Chloride, Cerium Chloride, Praseodymium Chloride, Neodymium Chlo-ride, Alkali Metals Chlorides, Heat Capacity, Differential Scanning Calorimetry 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0229.pdf 
 Identifier    ZNA-1999-54a-0229 
 Volume    54 
34Author    J. Breidung, H. Bürger, M. Senzlobei^, W. ThielRequires cookie*
 Title    High Resolution FTIR Spectrum of Chlorofluoroethyne  
 Abstract    , FCCC1, below 1000 cm -1 . Analysis of the v v v v v s , 2v 4 , v A + v 5 and 2i/ 5 Bands, and ab initio Calculations High resolution infrared spectra of FCCC1 have been measured and analyzed by polynomial methods. In the region below 350 cm -1 , the analysis is straightforward and yields parameters for the V4 = 1 and = 1 states. Between 350 and 800 cm -1 there are strong anharmonic interactions in the 2v 5 /u 4 + u^lu^llu^ tetrad which have been unravelled with the use of a model that employs ab initio interaction constants. Observed and theoretically predicted wavenumbers are in excellent agreement for all bands studied. 
  Reference    Z. Naturforsch. 54a, 236—244 (1999); received December 2 1998 
  Published    1999 
  Keywords    Infrared Spectrum, High Resolution, Alkyne, Fermi Resonance, ab initio Calculations 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0236.pdf 
 Identifier    ZNA-1999-54a-0236 
 Volume    54 
35Author    Hsing-Ya LiRequires cookie*
 Title    Determination of Multiple Steady States in an Active Membrane Transport Model  
 Abstract    A necessary and sufficient condition is applied to determine the possibility of multiple positive steady states in a complex, active membrane transport model with a cycle, which is performed by pump pro-teins coupled to a source of metabolic energy. A set of rate constants and two corresponding steady states are computed. Hysteresis phenomena are observed. A signature of multiplicity is derived, which can be applied in mechanism identifications if steady-state concentrations for some species are measured. The bifurcation of multiple steady states is also displayed. 
  Reference    Z. Naturforsch. 54a, 245—250 (1999); received September 11 1998 
  Published    1999 
  Keywords    Multiple Steady States, Bifurcation, Active Membrane Transport Models 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0245.pdf 
 Identifier    ZNA-1999-54a-0245 
 Volume    54 
36Author    G. Abed, SalimM. KhalilRequires cookie*
 Title    Amel  
 Abstract    MINDO-forces calculations have been performed on the uncatalysed and acid-catalysed Friedel-Crafts reaction between CH 3 F and CH 4 . It has been found that the catalysed reaction is exothermic, spontaneous and has a smaller potential-energy barrier than the uncatalysed reaction. The mechanisms for uncatalysed and catalysed reactions are discussed. 
  Reference    Z. Naturforsch. 54a, 251—255 (1999); received December 22 1998 
  Published    1999 
  Keywords    Melting, Liquid Structure, Molecular Liquids 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0251.pdf 
 Identifier    ZNA-1999-54a-0251 
 Volume    54 
37Author    B. Karabulut, R. Tapramaz, A. BulutRequires cookie*
 Title    EPR Studies of Cu 2+ in dl-Aspartic Acid Single Crystals  
 Abstract    EPR studies of Cu 2+ doped dl-Aspartic Acid [NH 2 CH(CH 2 COOH)COO] powder and single crystal have been carried out at 113 and 300 K. The principal hyperfine and g values, covalancy parameter, mixing coefficients and Fermi-contact term of the complex were obtained, and the ground-state wavefuntion of the Cu 2+ ion in the lattice has been constructed. 
  Reference    Z. Naturforsch. 54a, 256—260 (1999); received January 11 1999 
  Published    1999 
  Keywords    Electron Paramagnetic Resonance, dl-Aspartic Acid, Amino Acid 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0256.pdf 
 Identifier    ZNA-1999-54a-0256 
 Volume    54 
38Author    B.Thimme Gowda, D.Krishna Bhat, Hartmut Fuess, Alarich WeissRequires cookie*
 Title    C1 NQR Spectra of Substituted N-(Phenyl)-2^-THchloroacetamides  
 Abstract    Several substituted acetamides, XX: 6 H 5 _ V NHC0CC1 3 (X=CH ? , N0 2 , or Br and y= 1 or 2) have been synthesized and studied by NQR. The effect of ring substitution on the average v(35 Cl) NQR of the trichloroacetyl group is not substantial, but it affects the crystal structure of the substituted com-pounds. The NQR spectra of X y C 6 H 5 NHCOCCl 3 (where X } .=4-CH 3 , 4-N0 2 , and 2,3-(CH 3) 2) show six 35 C1 NQR frequencies, each indicating the presence of two molecules in their respective asym-metric units. The temperature dependence of v (35 C1) NQR of N-(4-methylphenyl)-2,2,2-trichloroacet-amide reveals that it undergoes a first order phase transition around 205 K. Its spectrum shows six lines up to 205 K and three lines thereafter. The latter triplet part of the spectrum fades out around 250 K due to librational motions in the crystal lattice, as the torsional motions of the CC1 3 group are easily excit-ed. The 35 C1 NQR spectra of all the methylsubstituted amides have been compared with those of the corresponding chlorosubstituted compounds. Generally there is no systematic variation of the mean val-ues of v(35 Cl) NQR or the trichloroacetyl group with the substituents in the phenyl ring. The co C-Cl frequencies of the trichloroacetyl group of all the v-substituted N-(phenyl)-2,2,2-trichloroacetamides have been estimated using NQR substituent parameters (k) and the frequencies of N-(phenyl)-2,2,2-tri-chloroacetamide. Agreement between these values and the experimental frequencies is quite good. The v(35 Cl) NQR of these amides has also been correlated with of the substituents. Further v (35 C1) NQR spectra of mono-and trichloroacetamides have been correlated. 
  Reference    Z. Naturforsch. 54a, 261—267 (1999); received January 29 1999 
  Published    1999 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0261.pdf 
 Identifier    ZNA-1999-54a-0261 
 Volume    54 
39Author    Sebastian Fischer, Andreas Weiler, Dieter Fröhlich, OttoE. RösslerRequires cookie*
 Title    Kleiner-Attractor in a Piecewise- Linear C 1 -System  
 Abstract    A maximally simple 3-variable ODE with a single letter-V shaped nonlinearity is shown to reproduce the experimentally discovered Kleiner chaos. Further numerical and analytical studies are encouraged. 
  Reference    Z. Naturforsch. 54a, 268—269 (1999); received December 22 1998 
  Published    1999 
  Keywords    Chaotic Attractors, Spiral-type Chaos, 2-Domain Piecewise-Linear Systems, Dynamical Prototype, Simplicity 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0268_n.pdf 
 Identifier    ZNA-1999-54a-0268_n 
 Volume    54 
40Author    Wilfried Schröder, Hans-Jürgen TrederRequires cookie*
 Title    Ertel's Potential Vorticity and Irreversible Processes  
 Abstract    According to Ertel's potential vorticity the thermodynamical parameters in the equation of state define the forces which move the vortices and modify them in space and time. 
  Reference    Z. Naturforsch. 54a, 270—271 (1999); received January 8 1999 
  Published    1999 
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 TEI-XML for    default:Reihe_A/54/ZNA-1999-54a-0270_n.pdf 
 Identifier    ZNA-1999-54a-0270_n 
 Volume    54 
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