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1988 (183)
1Author    Gerhard KlagesRequires cookie*
 Title     
 Abstract    o le k ü lin te r n e D ip o lo rie n tie ru n g u n d d ie le k tris c h e A b s o rp tio n in v e rd ü n n te r L ö s u n g b ei M ik r o -u n d S u b m illim e te rw e lle n . IV . C h lo rm e th y l-V e rb in d u n g e n The dielectric loss of eight molecules with the polar group in aromatic bonds and three in aliphatic bonds has been measured in very dilute solutions of cyclohexane at 20 °C. The measurements have been made at microwave frequencies in the range 2 to 130 GHz and at five wave numbers in the range 8 to 85 cm " 1 (generated by a pumped molecular laser). These measurements are supplemented using a Fourier transform spectrometre up to 300 cm-1. The dielectric loss spectra e"(v) have been separated into a number of absorption regions (three or four in the microwave area) using the two variable Mori formalism. The power absorption spectra a(v) are fitted to the Lorentzian shapes in order to determine the FIR resonances. The dielectric dispersion step determined from loss measurements contains the contributions from all orientational processes of the permanent molecular dipole moment. The distribution of relaxa­ tion times indicates that the polar group reorientates by a fast intramolecular rotational process in five of the eight aromatic molecules investigated. Furthermore these five substances show character­ istic broad resonance centred at approximately 39 cm-1. In order to determine the influence of the other substituted groups, the components of the dipole moment parallel and perpendicular to the internal axis of rotation are calculated from the dispersion steps. The perpendicular component does contribute as well to the Debye relaxation according to the Budo model as to the Poley and FIR absorptions. The relative magnitudes of these contributions are rather similar in the five molecules. In two other molecules, the intramolecular orientational process plays a relatively minor role due to the steric hindrance by a neighbouring group. However in dichloro-o-xylene, the two neighbour­ ing groups do not prevent the fast process except that the net dipole moment is significantly reduced. Again, due to steric hindrance, the aliphatic bonded group molecules do not exhibit the fast dipolar orientational process or the characteristic resonance at 39 cm-1. 
  Reference    Z. Naturforsch. 43a, 1—13 (1988); eingegangen am 7. Oktober 1987 
  Published    1988 
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 TEI-XML for    default:Reihe_A/43/ZNA-1988-43a-0001.pdf 
 Identifier    ZNA-1988-43a-0001 
 Volume    43 
2Author    J. Peinke, J. Parisi, B. Röhricht, O. E. Rössler, W. MetzlerRequires cookie*
 Title      
 Abstract    Generalized Mandelbrot sets arise in perturbed (non-analytic) versions of the complex logistic map. Numerically, it contains smooth portions as shown previously. To exclude that this result is specific to particular initial conditions only, the structure of the analogue to the Fatou set is looked at in the region in question. The set of non-divergent points is being "eaten up" by a smooth invading boundary. Therefore, the same type of decomposition applies independent of position in parameter space, in the region in question. 
  Reference    Z. Naturforsch. 43a, 14—16 (1988); received October 15 1987 
  Published    1988 
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 TEI-XML for    default:Reihe_A/43/ZNA-1988-43a-0014.pdf 
 Identifier    ZNA-1988-43a-0014 
 Volume    43 
3Author    Georg Purwins, Christian Radehaus, Jürgen BerkemeierRequires cookie*
 Title    Hans  
 Abstract    We investigate experimentally stationary stable states of activator (w) inhibitor (v) type systems corresponding to the reaction diffusion equation S ■ v = Av + w — v; w = a Aw + f(w) — v; S, a — const > 0 with / (w) monotonically increasing for small and decreasing for large |w|. We first describe some general mathematical properties and present qualitative results obtained from numerical calcula­ tions. We then investigate experimentally electrical networks described by the spatially discretized version of the above equation. Calculation and experiment are in good agreement. We also interprete a two dimensional-network as an equivalent circuit for a composite material consisting of a linear and a nonlinear layer with an s-shaped current density electric field characteristic. This model is used for a phenomenological description of spatial structures and global current voltage characteristics observed experimentally in pin-diode like and gas discharge devices. The model accounts very well for the experimental results obtained so far. It is concluded that the above equation and the corresponding experimental setup are of great interest for fundamental investigations of self con­ trolled processes in nature. E x p e r im e n ta l I n v e s tig a tio n o f S p a t ia l P a t t e r n F o r m a tio n in P h y s ic a l S y s te m s o f A c tiv a to r I n h ib ito r T y p e 
  Reference    Z. Naturforsch. 43a, 17—29 (1988); received October 10 1987 
  Published    1988 
  Keywords    Activator Inhibitor System, Reaction Diffusion System, Electrical Network, Semicon­ ductor, Gas Discharge 
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 TEI-XML for    default:Reihe_A/43/ZNA-1988-43a-0017.pdf 
 Identifier    ZNA-1988-43a-0017 
 Volume    43 
4Author    NeueRequires cookie*
 Title     
 Abstract    2H-NMR relaxation time studies were performed on the adsorption system anthracene + cyclo-hexane/graphite at 295.2 K. Translational and rotational diffusion coefficients are determined for adsorbed anthracene molecules. No trace of rotational anisotropy with respect to the surface was found rendering the term orientation meaningless for a description of the structure of the adsorbed layer. Instead, a model is proposed viewing the solvent as the primary component forming a foam-like hollow structure on top of the solid, where each cavity contains an anthracene molecule which performs almost isotropic rotational diffusion. A n th ra c e n e A d s o rb e d a t th e S o lid /L iq u id I n te r fa c e . A 2H -N M R S tu d y o f th e D y n a m ic s a n d S tr u c tu r e 
  Reference    Z. Naturforsch. 43a, 30—34 (1988); received September 30 1987 
  Published    1988 
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 TEI-XML for    default:Reihe_A/43/ZNA-1988-43a-0030.pdf 
 Identifier    ZNA-1988-43a-0030 
 Volume    43 
5Author    -S Montjoie, W. Müller-Warmuth, Hildegard Stiller, J. StanislawskiRequires cookie*
 Title     
 Abstract    'H NMR spin-lattice relaxation times Tx and -if accessible -level-crossing peaks and inelastic neutron scattering spectra have been measured for solid 2-and 3-methylfuran, 2-and 3-methyl-thiophene, 3-and 4-methylpyrazole, 1-methylimidazole, and 5-methylisoxazole. From the tunnel splittings, the torsional excitations and the NMR relaxation rates, the molecular dynamics of the methyl rotators has been evaluated between the limits of quantum tunnelling at low temperatures and thermally activated random reorientation at elevated temperatures. M e th y l G ro u p R o ta tio n a n d T u n n e llin g in C r y s ta ls o f 5 -M e m b e re d R in g M o le c u le s 
  Reference    Z. Naturforsch. 43a, 35—42 (1988); received October 1 1987 
  Published    1988 
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 TEI-XML for    default:Reihe_A/43/ZNA-1988-43a-0035.pdf 
 Identifier    ZNA-1988-43a-0035 
 Volume    43 
6Author    Pálinkás, Y. Tamura, E. Spohr, K. HeinzingerRequires cookie*
 Title     
 Abstract    The structure of liquid methanol as a function of the molecular polarity has been studied by MD simulations. The results obtained by scaling the partial Coulombic charges located at the molecular interaction sites show that the polar forces leading to the hydrogen bonding phenomena also influence the relative orientation of nearest neighbor molecules and thus their local packing. It is shown that hydrogen bonding in liquid methanol contributes considerably to the X-ray structure function. The changes with polarity of the pair interaction energy distributions, the intramolecular geometry, and the vibrational frequencies are reported. The results are compared with those obtai­ ned from RISM calculations. M o le c u la r P o la r ity a n d th e S tr u c tu r e o f L iq u id M e th a n o l 
  Reference    Z. Naturforsch. 43a, 43—46 (1988); received October 8 1987 
  Published    1988 
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 TEI-XML for    default:Reihe_A/43/ZNA-1988-43a-0043.pdf 
 Identifier    ZNA-1988-43a-0043 
 Volume    43 
7Author    Olaf Böttcher, DieterH. SutterRequires cookie*
 Title     
 Abstract    itro g e n Q u a d r u p o le H y p e r f in e S t r u c t u r e in th e R o ta tio n a l S p e c tr u m o f 2 -, 3 -, a n d 4 -F lu o ro -B e n z o n itrile . A C o m p a ra tiv e H ig h R e s o lu tio n M ic ro w a v e F o u r ie r T r a n s f o r m S tu d y A microwave Fourier transform study of the rotational spectrum of 3-fluoro-benzonitrile was carried out to study the 14N quadrupole coupling and to give improved rotational constants and centrifugal distortion parameters. In order to fully exploit the high resolution inherent to the experimental technique, frequencies, linewidths, intensities and phases were directly fitted to the observed transient emission signals. The quadrupole coupling constants are discussed in comparison to those of the related molecules 2-fluoro-benzonitrile, 4-fluoro-benzonitrile, and benzonitrile itself. For this comparison a sufficient number of hfs-patterns of the latter molecules was remeasured to derive coupling constants of comparable reliability. The four molecules may be grouped into two pairs. In benzonitrile and in 3-fluoro-benzonitrile the CN-bond shows a smaller deviation from cylindrical symmetry than in 2-and 4-fluoro-benzonitrile. 
  Reference    Z. Naturforsch. 43a, 47—58 (1988); received October 14 1987 
  Published    1988 
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 TEI-XML for    default:Reihe_A/43/ZNA-1988-43a-0047.pdf 
 Identifier    ZNA-1988-43a-0047 
 Volume    43 
8Author    Requires cookie*
 Title     
 Abstract    h o to re a c tio n s o f 2 -A m in o -2 -P h e n y lin d a n -l,3 -E)io n e D e riv a tiv e s * 
  Reference    Z. Naturforsch. 43a, 59 (1988) 
  Published    1988 
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 TEI-XML for    default:Reihe_A/43/ZNA-1988-43a-0059.pdf 
 Identifier    ZNA-1988-43a-0059 
 Volume    43 
9Author    RomanF. NalewajskiRequires cookie*
 Title     
 Abstract    e n e r a l R e la tio n s b e tw e e n M o le c u la r S e n s itiv itie s a n d T h e ir P h y s ic a l C o n te n t* The molecular Legendre transformed representations are reexamined. They correspond to alter­ native sets of parameters defining the constraints imposed on the system. In the global description the molecular (equilibrium) states are defined by the global state parameter G = {N or p) and the state function / (r) = [y(r) or n(r)]; N is the system number of electrons, /u its chemical potential, v stands for the external potential due to the nuclei, and n is the electron density. In the local description, capable of defining non-equilibrium molecular density distributions, the state is defined by two state functions, g(r) = [n(r) or fi{r)] and / (r); here n(r) is the local chemical potential of the electron distribution in small volume element around r. The Maxwell cross differentiation identities in both approaches, relating various molecular sensitivities, are physically interpreted. A qualitative discussion of general relations between molecular sensitivities is given and their physical content and possible applications are commented upon. 
  Reference    Z. Naturforsch. 43a, 65—72 (1988); received September 11 1987 
  Published    1988 
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 TEI-XML for    default:Reihe_A/43/ZNA-1988-43a-0065.pdf 
 Identifier    ZNA-1988-43a-0065 
 Volume    43 
10Author    G. L. Hofacker, Lichtenbergstr, R. D. LevineRequires cookie*
 Title      
 Abstract    A principle of evolution of highly complex systems is proposed. It is based on extremal properties of the information I{X, 7) characterizing two states X and Y with respect to each other, I{X, Y) = H(Y) -H{Y/X), where H(Y) is the entropy of state Y,H(Y/X) the entropy in state Y given the probability distribu­ tion P(X) and transition probabilities P(Y/X). As I(X, 7) is maximal in P(Y) but minimal in P(Y/X), the extremal properties of I(X, 7) con­ stitute a principle superior to the maximum entropy principle while containing the latter as a special case. The principle applies to complex systems evolving with time where fundamental equations are unknown or too difficult to solve. For the case of a system evolving from X to Y it is shown that the principle predicts a canonic distribution for a state Y with a fixed average energy <£>. 
  Reference    Z. Naturforsch. 43a, 73—77 (1988); received July 11 1987 
  Published    1988 
  Keywords    Mutual information, Channel capacity, Maximum entropy principle, Extremal pro­ perties of information 
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 TEI-XML for    default:Reihe_A/43/ZNA-1988-43a-0073.pdf 
 Identifier    ZNA-1988-43a-0073 
 Volume    43 
11Author    Atsushi Kubo, Ryuichi Ikeda, Daiyu NakamuraRequires cookie*
 Title      
 Abstract    tu d ie s o n th e M o le c u la r D y n a m ic s o f A c e ty lfe rro c e n e in C r y s ta ls The temperature dependence of 'H spin-lattice relaxation time was determined at 20 MHz for solid acetylferrocene [(C5H5) (C5H4COCH3)Fe] from ca. 80 K up to the m.p. (359 K). Rather large activation energies of 21 and 24 kJ mol-1 for the C5 reorientations of the two crystallographically nonequivalent non-substituted cyclopentadienyl rings were obtained, indicating that the crystal has a closely packed structure. The two kinds of CH3 groups attached to the substituted cyclopenta­ dienyl rings were assumed to be approximately equivalent and gave a low activation energy of 4 kJ mol" for the C3 reorientation. No phase transition was observed in the relaxation times or in additional experiments of differential thermal analysis although the presence of two phase transi­ tions has been reported previously at temperatures immediately below the melting temperature by means of differential scanning calorimetry. 
  Reference    Z. Naturforsch. 43a, 78—80 (1988); received August 14 1987 
  Published    1988 
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 TEI-XML for    default:Reihe_A/43/ZNA-1988-43a-0078.pdf 
 Identifier    ZNA-1988-43a-0078 
 Volume    43 
12Author    S. Hirrle, Kemmler-SackRequires cookie*
 Title      
 Abstract    Energy Transfer in the System Ca3La2W2Ol2:Mn, Nd, Yb On codoping of the host Ca,La2W ,0,2 with Mn4T and Nd3+ or Mn4+ and Yb3 + , respectively, an efficient energy transfer Mn -> Nd or Mn4+ — > Yb3+ operates. The simultaneous introduc­ tion of Mn4 + , Nd3+ and Yb3+ yields additionally an energy transfer Nd3+ -» Yb3 + . The excitation, emission and diffuse reflectance spectra are discussed. E n e r g ie tr a n s f e r im S y s te m C a 3L a 2W 20 12 : M n , N d ,Y b 1. Einführung 
  Reference    Z. Naturforsch. 43a, 81—84 (1988); eingegangen am 23. Oktober 1987 
  Published    1988 
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 TEI-XML for    default:Reihe_A/43/ZNA-1988-43a-0081.pdf 
 Identifier    ZNA-1988-43a-0081 
 Volume    43 
13Author    Walter FabianRequires cookie*
 Title     
 Abstract    n d M e th y lb e n z o a te s . A S e m ie m p iric a l M o le c u la r O r b i ta l S tu d y The semiempirical AMI method is used to calculate relative proton affinities of a series of meta-and para-substituted benzaldehydes and methylbenzoates. Close agreement between the results of these calculations and experimental relative gas phase basicities could be obtained. The influence of a substituent on the stability of both neutral as well as protonated forms is estimated via isodesmic reactions. In any case the influence of a substituent is most pronounced in the protonated carbonyl compound. The contribution of the inductive/field effect of a substituent is approximated by the results of isolated molecule calculations. The resonance contribution is estimated by the charge transfer to or from the substituent as revealed by a Mulliken population analysis. Alternatively, the difference between isodesmic stabilization energies and isolated molecule results for the protonated compounds is taken as a measure for the resonance effect. Linear regression analyses with these substituent parameters show good correlation with both experimental as well as calculated relative basicities of the compounds studied. G a s P h a s e B a s ic ity o f S u b s titu te d B e n z a ld e h y d e s 
  Reference    Z. Naturforsch. 43a, 85—90 (1988); received November 4 1987 
  Published    1988 
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 Identifier    ZNA-1988-43a-0085 
 Volume    43 
14Author    Chao-Cheng Yang, Isao Okada, Masao Nomura, Makoto OkamotoRequires cookie*
 Title    The Isotope Effect of Li-Ions in Countercurrent Electromigration of Molten LiOH  
 Abstract    The relative difference, e, in the internal mobilities of 6Li and Li ions in molten LiOH has been measured with the Klemm method. In the investigated range of temperature from 763 K to 873 K, e has been determined to be 0.0068-0.0080 and seems to increase slightly with temperature. 
  Reference    Z. Naturforsch. 43a, 91—92 (1988); received December 1 1987 
  Published    1988 
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 Identifier    ZNA-1988-43a-0091_n 
 Volume    43 
15Author    K.J G Kruscha, B. PompeRequires cookie*
 Title    I n f o r m a tio n F lo w in I D M a p s  
 Abstract    An information theoretical description is given of the action of ID maps on probability measures (e.g. on ergodic invariant measures of chaotic maps). On the basis of a detailed analysis of the elements of information flow the problem of optimum measuring of initial states for state predictions is discussed. Moreover, we give an information theoretical description of the relaxation, under the action of a map, of an initial probability distribution to any, not necessarily steady, final distribution. In this connection we formulate an H-theorem for ID maps. 
  Reference    Z. Naturforsch. 43a, 93—104 (1988); received April 6 1987 
  Published    1988 
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 TEI-XML for    default:Reihe_A/43/ZNA-1988-43a-0093.pdf 
 Identifier    ZNA-1988-43a-0093 
 Volume    43 
16Author    S. Zachara, M. SzyncelRequires cookie*
 Title      
 Abstract    Absorption spectra in the far and intermediate infrared, as well as Raman and vibronic spectra were measured for three crystalline forms of four-ligand europium chelate with dibenzoylmethane and piperidine and a three-ligand chelate in the spectral ranges: 40-450, 450-4500, 0-4500 and 0-1600 cm " x, respectively. The analysis of the individual spectra enabled the identification of the frequencies corresponding to the vibrations of the Eu —O bond coupled with the lattice vibrations, and the frequencies of the intraligand vibrations. It is found that piperidine is bound to the complex molecule by hydrogen bond. T h e I n f r a r e d , R a m a n , a n d V ib ro n ic S p e c tr a o f E u ro p iu m C h e la te s 
  Reference    Z. Naturforsch. 43a, 105—109 (1988); received October 26 1987 
  Published    1988 
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 Identifier    ZNA-1988-43a-0105 
 Volume    43 
17Author    O. E. RösslerRequires cookie*
 Title      
 Abstract    A new experiment in the foundations of quantum mechanics is proposed. The existence of correlated photons -first seen by Wheeler -can be taken as a hint to devise a "double-wing" delayed choice experiment in Wheeler's sense. A path choice (polarization choice) measurement made on the one side should then block an interference type measurement made on the other side ("distant choice"). A precondition for the combined measurement to work in theory is that the correlated photons used are of the "prepolarized" (Selleri) rather than the "unpolarized" (Böhm) type. A first EPR experiment involving prepolarized photons was recently performed by Alley and Shih. It may be used as a partial experiment within the proposed experiment. 
  Reference    Z. Naturforsch. 43a, 110—114 (1988); received November 17 1987* 
  Published    1988 
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 TEI-XML for    default:Reihe_A/43/ZNA-1988-43a-0110.pdf 
 Identifier    ZNA-1988-43a-0110 
 Volume    43 
18Author    Claus KahlertRequires cookie*
 Title     
 Abstract    n a ly tic a l A p p r o x im a tio n s to T y p e I I I S e p a r a tio n T h r e s h o ld s in P o in c a r e H a lfm a p s The curves Qk, marking the frequency thresholds for type III separation in the parameter space of Poincare halfmaps, are investigated further analytically. In the limit of great values of their argument, the relaxation constant o, all frequency functions Qk are shown to grow algebraically -each with the same exponent being |. Furthermore, a perturbation expansion is presented that yields good results already at a level of approximation where the calculations can be performed 
  Reference    Z. Naturforsch. 43a, 115—122 (1988); received October 14 1987 
  Published    1988 
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 TEI-XML for    default:Reihe_A/43/ZNA-1988-43a-0115.pdf 
 Identifier    ZNA-1988-43a-0115 
 Volume    43 
19Author    J. A. Escriñá, M. L. Bañón, J. González-VelascoRequires cookie*
 Title      
 Abstract    flu e n c e o f S tr u c tu r e B r e a k in g a n d S tr u c tu r e F o rm in g Io n s o n th e D is s o c ia tio n M e c h a n is m o f A c e tic A c id in A q u e o u s S o lu tio n s Dedicated to Professor W. V ielstich on the Ocassion of his 65th Birthday. Using a rotating disc electrode, the dissociation rate of acetic acid in various aqueous electrolyte solutions is studied. Li + , Cs+ and (CH3)4N+ at 1 M concentration considerably modify the activa­ tion enthalpy and entropy of the reaction. Evidently the interaction between the cations and water influences the dissociation mechanism of the weak acid. In the presence of 1 molar Li+ the activated complex of acetic acid seems to contain only one water molecule instead of two in the other cases. 
  Reference    Z. Naturforsch. 43a, 123—128 (1988); received May 21 1987 
  Published    1988 
  Keywords    Dissociation mechanism, weak acids, structure breaking and structure forming ions 
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 TEI-XML for    default:Reihe_A/43/ZNA-1988-43a-0123.pdf 
 Identifier    ZNA-1988-43a-0123 
 Volume    43 
20Author    C. Margheritis, C. SinistriRequires cookie*
 Title      
 Abstract    This paper describes a method for a simple evaluation of the polarization energy in molten salt systems, by which it is possible to go, without heavy computational cost, from the rigid to the soft ion model. The method is based on the observation that, within the movements of single ions in the Monte Carlo chain, the deviation of the polarization energy is a linear function of the deviation of the Coulomb energy. An extended numerical application has been carried out for molten Lil at 800, 1200 and 1453 (b. p.) K. The parameters that are mostly affected by the used model are put into evidence. 
  Reference    Z. Naturforsch. 43a, 129—132 (1988); received November 19 1987 
  Published    1988 
  Keywords    Interionic potential, Polarization, Monte Carlo, Simulation, Molten Lil 
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 TEI-XML for    default:Reihe_A/43/ZNA-1988-43a-0129.pdf 
 Identifier    ZNA-1988-43a-0129 
 Volume    43 
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