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1996[X]
141Author    T. A. Mirnaya, G. G. Yaremchuk, S. V. VolkovRequires cookie*
 Title    Phase Diagrams of Binary Alkanoate Systems with Common Cation: Potassium Isobutyrate-Propionate, and Sodium Butyrate-Isobutyrate  
 Abstract    The phase diagrams of the binary mixtures of mesogenic potassium isobutyrate with non-meso-genic potassium propionate and mesogenic sodium butyrate with non-mesogenic sodium isobu-tyrate have been investigated by differential thermal analysis and hot stage polarization microscopy. Both systems have one eutectic and one metatectic phase equilibriums. Pecularities of liquid crystal formation in binary alkanoate systems with common alkali metal cation are discussed and compared with those of systems with common anion. 
  Reference    Z. Naturforsch. 51a, 957—959 (1996); received May 3 1996 
  Published    1996 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0957.pdf 
 Identifier    ZNA-1996-51a-0957 
 Volume    51 
142Author    HansH. Diebner, Thomas Kirner, OttoE. RösslerRequires cookie*
 Title    Time Reversibility and the Logical Structure of the Universe  
 Abstract    Both Fredkin's findings on the reversibility of logical oper-ations and the novel capability to integrate Newton's equa-tion of motion in an exactly reversible manner enables one to perform a gedankenexperiment in the form of a molecular dynamics simulation of the universe. This leads to a new validation of the reversible structure of the universe. Alterna-tively, the role of information needs to be upgraded in accor-dance with a recent proposal by Stonier. 
  Reference    Z. Naturforsch. 51a, 960—962 (1996); received March 11 1996 
  Published    1996 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0960_n.pdf 
 Identifier    ZNA-1996-51a-0960_n 
 Volume    51 
143Author    H.-G Köhne, M. StockhausenRequires cookie*
 Title    A Remark on the Two-State Model of Dielectric Relaxation  
 Abstract    The two state model with exchange between the tumbling modes of the relaxing molecules is treated by computer sim-ulation. Some results are given in dependence on the reorien-tational angular steps characterizing the respective states, which compare well with recent literature results obtained analytically. 
  Reference    Z. Naturforsch. 51a, 963—964 (1996); received May 15 1996 
  Published    1996 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0963_n.pdf 
 Identifier    ZNA-1996-51a-0963_n 
 Volume    51 
144Author    U. Ochs, M. SorgRequires cookie*
 Title    Non-Linear Generalization of the Relativistic Schrödinger Equations  
 Abstract    The theory of the Relativistic Schrödinger Equations is further developped and extended to non-linear field equations. The technical advantage of the Relativistic Schrödinger approach is demonstrated explicitly by solving the coupled Einstein-Klein-Gordon equations including a non-linear Higgs potential in case of a Robertson-Walker universe. The numerical results yield the effect of dynamical self-diagonalization of the Hamiltonian which corresponds to a kind of quantum de-coherence being enabled by the inflation of the universe. 
  Reference    Z. Naturforsch. 51a, 965—982 (1996); received November 11 1995 
  Published    1996 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0965.pdf 
 Identifier    ZNA-1996-51a-0965 
 Volume    51 
145Author    P. Lamparter, S. SteebRequires cookie*
 Title    Structure of Metallic Glasses: Experiments and Models  
 Abstract    The topological and the chemical short range order in metallic glasses is discussed by means of representative examples from the systems Ni-P, Ni-B, Nb-Ni, and Dy-Ni. The characterization of the chemical short range order, e.g. in terms of a short range order parameter, depends on the definition of an appropriate hypothetic statistical reference system. The consideration of the size effect is essential. Some structural features of metallic glasses point to relationships with the related individual crystalline phases, whereas other features show that the different types of metallic glasses have certain construction principles in common. Small angle scattering with hydrogenated metallic glasses suggests the presence of extended two-dimensional structures. Reverse Monte Carlo models reveal rather broad distributions of the local structural properties and show that metallic glasses are not built as assemblies of defined structural units. 
  Reference    Z. Naturforsch. 51a, 983—990 (1996); received June 3 1996 
  Published    1996 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0983.pdf 
 Identifier    ZNA-1996-51a-0983 
 Volume    51 
146Author    M. Grottel, A. Kozak, Z. PająkRequires cookie*
 Title    *H and 19 F NMR Study of Cation and Anion Motions in Guanidinium Hexafluorozirconate  
 Abstract    Proton and fluorine NMR second moments and spin-lattice relaxation times of polycrystalline guanidinium hexafluorozirconate and its deuterated analogue were studied in laboratory (60 MHz) and rotating (H, = 20 G) frames over a wide range of temperature. An analysis of the experimental results enabled us to reveal a dynamical inequivalence of two crystallographically independent cations and an unexpected high mobility of nonspherical anion dimers. A comparison of the ions dynamics in 2:1 complex studied with the guanidinium 1:1 and 3:1 complexes has shown a significant contribution of the hydrogen bonds to the potential barriers hindering the anion reorien-tations. At low temperatures a proton motion in the hydrogen bond and at 400 K a solid-solid phase transition have been discerned. 
  Reference    Z. Naturforsch. 51a, 991—996 (1996); received May 14 1996 
  Published    1996 
  Keywords    NMR, Ion Motions, Hydrogen Bonds, Phase Transitions 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0991.pdf 
 Identifier    ZNA-1996-51a-0991 
 Volume    51 
147Author    I. Pak, M. Hepp, D. A. Roth, G. Winnewisser, K.M T YamadaRequires cookie*
 Title    Detection of Ar-CH 4 Complexes in the 7jim Region by Diode Laser Spectroscopy  
 Abstract    The absorption spectrum of the Ar-CH 4 van der Waals complex was measured for the first time in the 7 pm region. The complexes were produced in a pulsed slit supersonic jet and detected by a tunable diode laser spectrometer with 40 MHz spectral resolution. The strongest absorption features of the Ar-CH 4 complex were observed in the spectral region 1310.57-1311.05 cm -1 , located between the Q(l) and the R(0) lines of the v 4 fundamental band of the methane monomer. It was found that the newly detected absorption lines belong to three Q-branches of the Ar-CH 4 complex. The transitions of these Q-branches are related to the Q(l) transition in the v 4 fundamental band of the methane molecule, which can rotate almost freely inside the complex. The three Q-branches have been assigned. 
  Reference    Z. Naturforsch. 51a, 997—1001 (1996); received May 22 1996 
  Published    1996 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-0997.pdf 
 Identifier    ZNA-1996-51a-0997 
 Volume    51 
148Author    Prasanta Chatterjee, Rajkumar RoychoudhuryRequires cookie*
 Title    Ion Acoustic Soliton in an Electron Beam Plasma  
 Abstract    The pseudopotential method is used to study ion acoustic compressive and rarefactive solitons in an electron beam plasma with hot isothermal electron beam and plasma electrons and warm ions. It is shown that for small amplitude cases our results completely agree with the published results. 
  Reference    Z. Naturforsch. 51a, 1002—1006 (1996); received March 29 1996 
  Published    1996 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-1002.pdf 
 Identifier    ZNA-1996-51a-1002 
 Volume    51 
149Author    Bernward StukeRequires cookie*
 Title    A Fundamental Structure of Continuum Mechanics I. Elastic Systems  
 Abstract    Continuum mechanics and thermodynamics are complementary areas of classical field theory. Their fundamental structure, however, is rather different according to the present view: on the one hand there is the equation of motion or the equivalent balance of momentum, on the other there is Gibbs' fundamental equation. In a preceding paper it has been shown that systems having a potential of acceleration possess a structure of continuum mechanics which corresponds to the one of thermodynamics. This discus-sion is extended to elastic systems. In this case a tensorial potential of acceleration must be introduced. The equation of motion derived for this extended structure contains two additional terms (reactive forces) not present in the conventional balance of forces. 
  Reference    Z. Naturforsch. 51a, 1007—1011 (1996); received October 31 1994 
  Published    1996 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-1007.pdf 
 Identifier    ZNA-1996-51a-1007 
 Volume    51 
150Author    AdelN. Asaad, El Sayed, H.El AshryRequires cookie*
 Title    A Theoretical Study on Intramolecular Cyclization of Azidobenzotriazine to Tetrazolobenzotriazines  
 Abstract    The cyclization equilibrium of 3-azidobenzo[l,2,4]triazine (la) with tetrazolo[5,l-b]benzo[l,2,4] triazine (linear isomer, lb) and tetrazolo[5,l-c]benzo[l,2,4]triazine (angular isomer, lc) is investi-gated computationally using the molecular orbital MNDO-SCF method. The results suggest that the higher reactivity of atom N(4) with respect to N(2) towards the cyclization is due to: (i) The negative charge density upon N(4) is 1.3 time larger than that upon N(2); (ii) In the highest occupied molecular orbital (HOMO) the coefficient at N(4) is 2.4 times larger than that at N(2); (iii) The heat of reaction to (lc) and (lb) are calculated to be —74.9 and —14.8 kJ mol" 1 , respectively; (iv) The thermodynamic stabilization of the angular isomer (1 c) is 60.1 kJ mol" 1 larger than that of the linear isomer (1 b), and (v) The potential barrier heights calculated for the cyclization favour the angular product. From these considerations and the perturbation theory, the calculated yield of the cycliza-tion reaction is 70.8+0.1% of lc, which is in good agreement with the experimental yield 64%. 
  Reference    Z. Naturforsch. 51a, 1012—1018 (1996); received March 18 1996 
  Published    1996 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-1012.pdf 
 Identifier    ZNA-1996-51a-1012 
 Volume    51 
151Author    S. Heinemann, H. Kresse, S. Saito, D. DemusRequires cookie*
 Title    Dielectric Studies of a Series of Liquid Crystalline Pyridine Derivates  
 Abstract    Measurements of the temperature and frequency dependence of dielectric constants have been performed for five homologues in the range 100 Hz -10 MHz. These substances exhibit a negative anisotropy of the dielectric constants and two relaxation regions (rotation of the molecules around the short resp. long axis) in the investigated frequency range. Even in the crystalline state dipolar reorientations are possible which have been interpreted as rotations of the alkoxy group. Changes of the static dielectric constants, relaxation frequencies and transition entropies are discussed as a measure of structural changes passing the several liquid crystalline phases. 
  Reference    Z. Naturforsch. 51a, 1019—1026 (1996); received May 3 1996 
  Published    1996 
  Keywords    Dielectric constants, Relaxation frequencies, Transition entropies, Tilted smectic phases 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-1019.pdf 
 Identifier    ZNA-1996-51a-1019 
 Volume    51 
152Author    Hideta Ishihara, Shi-Qi Dou, Keizo Horiuchi, V. G. Krishnan, Helmut Paulus, Hartmut Fuess, Alarich WeissRequires cookie*
 Title    Isolated versus Condensed Anion Structure: the Influence of the Cation Size and Hydrogen Bond on Structure and Phase Transition in MXj" Complex Salts. 2,2-Dimethyl-l,3-propanediammonium Tetrabromocadmate(II) Monohydrate, Dimethylammonium Tetrabromozincate(II), and Dimethylammonium Tetrabromocadmate(II)  
 Abstract    In the course of work on the anion condensation of Cd and Zn halides, the crystal structures and 79,81 Br NQR spectra of 2,2-dimethyl-l,3-propanediammonium tetrabromocadmate(II) monohy-drate (1) and dimethylammonium tetrabromozincate(II) (2), and 79-81 Br NQR spectra of dimethyl-ammonium tetrabromocadmate(II) (3) have been studied. An isolated [CdBrJ 2-ion of the salt [H 3 NCH 2 C(CH3) 2 CH 2 NH 3 ]CdBr 4 • H z O (1) is formed, with polar orthorhombic space group Pbc2j, Z = A, a = 645.5(3), b = 1628.3(8), c -1389.5(6) pm. [(CH 3) 2 NH 2 ] 2 ZnBr 4 (2) has also an isolated anion lattice, with monoclinic space group, P2 l /c, Z = 4, a = 870.6(3), b = 1195.6(4), c = 1628.9(5) pm, ß = 121.84(1)°. The 81 Br NQR spectrum of (1) is a quartet (v in MHz, T = 77 K/ 303 K): v, = 68.403/64.278; v 2 = 65.296/62.663; v 3 = 56.525/54.660; v 4 = 43.211/45.422. The 81 Br NQR spectrum of (2) is a quartet too (v in MHz, T= 77 K/300 K): v, = 66.848/64.784; v 2 = 63.152/ 61.883; v 3 = 57.498/55.890; v 4 = 49.416/50.224. The 81 Br NQR spectrum of [(CH 3) 2 NH 2 ] 2 CdBr 4 (3) is also a quartet (v in MHz, T =77 K/310 K): v t = 68.606/67.272; v 2 = 65.806/63.296; v 3 = 58.096/ 57.369; v 4 = 55.757/53.393. The change of NQR frequencies with temperature is smooth for all three compounds. One of the 81 Br NQR lines in both (1) and (2) increases slightly in frequency with increasing T. In the compound (1), the H 2 0 coordinates to NH 3 groups and to bromines forming a distorted tetrahedron (Br.. .) 2 • • • H 2 0 • • • (... HN) 2 , the six angles lying between 69° and 131°. The relations between the bromine NQR and the crystal structures are discussed for the title compounds. 
  Reference    Z. Naturforsch. 51a, 1027—1036 (1996); received June 3 1996 
  Published    1996 
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 Identifier    ZNA-1996-51a-1027 
 Volume    51 
153Author    A. Kawski, Z. Gryczyński, I. Gryczyński, J. R. Lakowicz, G. PiszczekRequires cookie*
 Title    Photoselection of Luminescent Molecules in Anisotropic Media in the Case of Two-Photon Excitation. Part II. Experimental Studies of Hoechst 33342 in Stretched Polyvinyl alcohol) Films  
 Abstract    It was found by investigating dichroism and emission anisotropy in the case of one-and two-pho-ton excitation of Hoechst 33342 [bis-benzimide,2,5'-bi-lH-benzimidazole, 2'-(4-ethoxyphenyl)-5-5(4-methyl-l-piperazinyl)] in stretched poly(vinyl alcohol) (PVA) films, that the absorption and fluores-cence transition moments lie along the long molecular axis of the molecule studied. The slight deviation of the transition moment direction in fluorescence (about 8°) from that in absorption can be due to the incomplete linearity of the Hoechst molecule. 
  Reference    Z. Naturforsch. 51a, 1037—1041 (1996); received June 25 1996 
  Published    1996 
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 Identifier    ZNA-1996-51a-1037 
 Volume    51 
154Author    Zoran Marković, Stanimir Konstantinović, Ivan GutmanRequires cookie*
 Title    The Dependence of Vicinal Proton-Proton Coupling Constants of Norbomenes on Molecular Structure  
 Abstract    A modification of the Karplus equation, containing four mutually independent structural terms and five adjustable parameters, is put forward. The new structural factor, intro-duced into this modification is sin {6 1 -I-6 2)/2. The new equa-tion reproduces experimental NMR vicinal coupling con-stants of norbornenes with a standard deviation of about 0.45 Hz. 
  Reference    Z. Naturforsch. 51a, 1042—1044 (1996); received April 27 1996 
  Published    1996 
  Keywords    Norbornenes, Coupling Constants, Molecular Mechanics, Karplus Equation, NMR 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-1042_n.pdf 
 Identifier    ZNA-1996-51a-1042_n 
 Volume    51 
155Author    H. Stumpf, W. PfisterRequires cookie*
 Title    Resolution of constraints and gauge equivalence in algebraic Schrödinger representation of quantum electrodynamics  
 Abstract    The algebraic formalism of QED is expounded in order to demonstrate both the resolution of constraints and to verify gauge equivalence between temporal gauge and Coulomb gauge on the quantum level. In the algebraic approach energy eigenstates of QED in temporal gauge are represented in an algebraic GNS basis. The corresponding Hilbert space is mapped into a functional space of generating functional states. The image of the QED-Heisenberg dynamics becomes a functional energy equation for these states. In the same manner the Gauß constraint is mapped into functional space. By suitable transformations the functional image of the Coulomb forces is recovered in temporal gauge. The equivalence of this result with the functional version of QED in Coulomb gauge is demonstrated. The meaning of the various transformations and their relations are illustrated for the case of harmonic oscillators. If applied to QCD this method allows an exact derivation of effective color "Coulomb" forces, in addition it implies a clear conception for the incorporation of various algebraic representations into the formal Heisenberg dynamics and establishes the algebraic "Schrödinger" equation for quantum fields in functional space. PACS 12.20: Quantum electrodynamics 
  Reference    Z. Naturforsch. 51a, 1045—1066 (1996); received June 17 1996 
  Published    1996 
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 Identifier    ZNA-1996-51a-1045 
 Volume    51 
156Author    T.Lakshmi Kasturi, Geetha Jayaram, V. G. KrishnanRequires cookie*
 Title    EPR Investigation of V0 2+ Ion in IC(NH 2 ) 3 ] 3 A1F 6 Single Crystals  
 Abstract    X-band EPR spectra have been recorded at room temperature for V0 2+ impurity in single crystals of tris-Guanadiniumhexafluoroaluminate, [C(NH 2) 3 ] 3 A1F 6 . 19 F super hyperfine structure has been observed on the 51 V hyperfine lines. V0 2+ replaces Al 3+ to form an effective VOF 5 complex. There are three possible V-O bond orientations in the A1F 6 octahedron but with differing occupancy factors. Bonding parameters have been evaluated. 
  Reference    Z. Naturforsch. 51a, 1067—1072 (1996); received June 28 1996 
  Published    1996 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-1067.pdf 
 Identifier    ZNA-1996-51a-1067 
 Volume    51 
157Author    J. Brunvoll, B. N. Cyvin, S. J. Cyvin, G. Brinkmann, J. BornhöftRequires cookie*
 Title    Enumeration of Chemical Isomers of Polycyclic Conjugated Hydrocarbons with Six-Membered and Five-Membered Rings  
 Abstract    Polygonal systems P consist of exclusively hexagons and pentagons. They correspond (as chem-ical graphs) to a certain class of polycyclic conjugated hydrocarbons. This class includes proto-fullerenes. General formulations for the maximum numbers of internal vertices for P systems with p<6 are derived; here p is the number of pentagons. The C"H S chemical formulas of P systems are studied with special emphasis on the semibuckminsterfullerene (C 30 H 12), circum-semibuckminster-fullerene (C 58 H 16) and corannulene (C 20 H 10) isomers. Numbers of all C"H S isomers for P systems with r< 6 are computed; here r is the total number of polygons. 
  Reference    Z. Naturforsch. 51a, 1073—1078 (1996); received April 4 1996 
  Published    1996 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-1073.pdf 
 Identifier    ZNA-1996-51a-1073 
 Volume    51 
158Author    Ilie Fishtik, István Nagypál, Ivan Gutman, Str Academiei, Republica MoldovaRequires cookie*
 Title    Novel Formulation of the Gibbs-Energy Change in Terms of Stoichiometrically Unique Response Reactions  
 Abstract    The equation for the change of Gibbs energy in complex chemical systems is reformulated in terms of the newly conceived response reactions (RERs). The present formulation has the remarkable property of being unique: the composition of the species unequivocally determines the response reactions and via them the change of the Gibbs energy of the system. Furthermore, it enables one to reinterpret and rationalize some basic concepts of chemical thermodynamics, as coupling between reactions, sensitivity coefficients, etc. 
  Reference    Z. Naturforsch. 51a, 1079—1083 (1996); received July 9 1996 
  Published    1996 
  Keywords    Chemical thermodynamics, Sensitivity analysis, Response reactions, Thermodynamic coupling (of chemical reactions) 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-1079.pdf 
 Identifier    ZNA-1996-51a-1079 
 Volume    51 
159Author    T. Böttjer, M. StockhausenRequires cookie*
 Title    EPR Spectroscopy of Some Mn 2 + Doped Langbeinites with Regard to Low Temperature Phases  
 Abstract    Electron paramagnetic resonance (EPR) spectra of Mn 2+ centers in 11 langbeinites, A 2 + B 2 + (S0 4) 2 ~, with A + = NH;,K + ,Rb + or Tl + and B 2+ -Mg 2 + ,Ca 2 + ,Zn 2+ or Cd 2+ , are measured over relatively large temperature ranges chosen to cover phase transitions, if any. For 7 langbeinites which do not contain Mg 2 + , phase transitions are observed, but no more than one low temperature phase is distinguishable by EPR. Except for the K-Zn langbeinite, only one defect center is noticeable in that phase. The low temperature EPR parameters are reported, and their temperature dependence is discussed with respect to correlations between structure and phase transition characteristics and to the trigger mechanism. 
  Reference    Z. Naturforsch. 51a, 1084—1090 (1996); received June 16 1996 
  Published    1996 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-1084.pdf 
 Identifier    ZNA-1996-51a-1084 
 Volume    51 
160Author    F. Lorenzo, J.-U Grabow, H. DreizlerRequires cookie*
 Title      
 Abstract    We report on an observation in molecular beam rotational spectroscopy: using Methane rather than rare gases as carrier extends the range of observable transitions towards levels of higher rotational energy. 
  Reference    Z. Naturforsch. 51a, 1091—1095 (1996); received July 16 1996 
  Published    1996 
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 TEI-XML for    default:Reihe_A/51/ZNA-1996-51a-1091.pdf 
 Identifier    ZNA-1996-51a-1091 
 Volume    51 
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