bluuebunny/crossref_metadata_2025_split huggingface dataset:
Application of a Generalized Frobenius-Perron Operator Scheme to Multivariate Nonlinear Dynamical Systems
Authors: Stoop R. , Steeb W.-H. 
Published: February 2015

Abstract
The concept of generalized Frobenius-Perron operators is applied to multivariante nonlinear dynamical systems, and the associated generalized free energies are investigated. As important applications, diffusion-related free energies obtained from normally and superlinearly diffusive one-dimensional maps are discussed.
Stable Kink-Antikink Pairs in Bistable Reaction-Diffusion Systems with Strong Nonlocalities
Authors: Christen Thomas 
Published: February 2015

Abstract
We investigate the statics, nucleation, and dynamics of stable kink-antikink pairs (KAP) in a one-dimensional, one-component reaction-diffusion equation with a piecewise linear nonlinearity. The stabilization of the KAP is due to the presence of a strongly nonlocal inhibitor. We find a saddle-node bifurcation of a metastable KAP with a separation proportional to In L, where L is the length of the sample. The KAP becomes globally stable at a characteristic separation proportional to √L. The nucleation of a KAP from the metastable uniform state differs from the case without nonlocality mainly by a change of the activation energy induced by the nonlocality. Furthermore, we investigate the dynamics of the stable KAP in the presence of an external driving force and a diluted density of pointlike impurities; in particular, we derive expressions for the mobility and the average elongation of the KAP.
An Approach to a Generalized Rössler System via Mode Analysis
Authors: Meyer Th. , Bünner M. J. , Kittel A. , Parisi J. 
Published: February 2015

Abstract
We investigate the generalized Rössler system introduced by Baier and Saale. They have linearly coupled additional degrees of freedom to the original Rössler system in order to construct a set of equations which shows maximum instability at an arbitrary dimension N, i. e., N - 2 positive Lyapunov exponents. We present a transformation into a mode picture. It enables a qualitative understanding of the mechanism generating the dynamics of this complex system. The advantages of our approach are demonstrated for the exemplary case N = 5.
Deterministic Continuous Molecular-Dynamics-Simulation of a Chemical Oscillator
Authors: Diebner Hans H. , Rössler Otto E. 
Published: February 2015

Abstract
A macroscopic chemical oscillator involving 3 autocatalytic second-order reactions is simulated microscopically. A deterministic Newtonian simulation involving 1024 particles with a smooth 1/r potential in two dimensions is presented.
ESR of Gamma Irradiated Single Crystals of Acetylcholine Picrate and Methoxycarbonylcholine Picrate Hemihydrate
Authors: Birey Mehmet , Zengin D. Mehmet , Aktas Huseyin , Alicilar Ahmet 
Published: February 2015

Abstract
We have observed two radicals in the ESR spectra of γ-irradiated single crystals of acetylcholine picrate and methoxycarbonylcholine picrate hemihydrate. These radicals have been identified as the CH3COOH and -CH2CH2 respectively.
Unusual Absorption and Fluorescence Properties of p-Substituted Stilbenes in Poly (vinyl alcohol) Films
Authors: Kawski A. , Kukliński B. , Nowosielski T. 
Published: February 2015

Abstract
The behaviour of absorbance, fluorescence and emission anisotropy of linear molecules with one double bond, i.e. 4-amino-4'-nitrostilbene (ANS), 4-dimethylamino-4'-nitrostilbene (DNS) and 4,4'-diphenylstilbene (DPS), was examined in polyvinyl alcohol) (PVA) films at different temperatures (293-423 K). The unusual behaviour of absorption and fluorescence properties of the molecules in­ vestigated, similar to those of linear polyenes in PVA, was, however, less pronounced.
Sub-Doppler Spectroscopy of Ammonia Near 570 GHz
Authors: Belov S. P. , Klaus Th. , Plummer G. M. , Schieder R. , Winnewisser G. 
Published: February 2015

Abstract
We have employed the Cologne terahertz spectrometer [ 1,2] to observe Lamb dip and crossover phenomena in rotational spectra at 572 GHz. Because of the large power output of the backward wave oscillators used in the system, no special means are required to induce this saturation effect; the coincidentally reflected radiation from the bolometer present in our quasi-optical absorption cell is sufficient to saturate the υz = 0 sub-group. This effect has allowed the observation of the three previously unresolved hyperfine components of the l4NH3 A ← S, JK = 10 ← 00 transition, and was also observed for the analogous 15NH3 transition in natural abundance (i. e. 0.366 %). These measurements indicate a possible improvement of molecular transition frequencies in the submillimeter region.
Hyperfine Interaction Induced K-type Doubling in the mmw Spectrum of HS33SH
Authors: Saleck Axel H. , Winnewisser Gisbert 
Published: February 2015

Abstract
The rotational spectrum of the disulfane isotopomer HS33SH has been recorded and assigned between 70 and 300 GHz. In the analysis, rotational constants and 33S hyperfine parameters are derived, the latter accounting for nuclear electric quadrupole as well as nuclear spin -rotation hyperfine interactions. The quadrupole constants are in qualitative agreement with a published ab-initio calculation. The electric field gradient principal axes are considerably rotated against the principal inertial axes, giving rise to off-diagonal elements in the electric field gradient tensor. In combination with the very small inertial asymmetry of the molecule, this causes the A'-doubling in the lowest rotational levels to be dominated by the hyperfine structure rather than the inertial asymmetry contributions. By diagonalization of the quadrupole tensor, an estimate for the dihedral angle (η≈94°) can be obtained, in good agreement with a previous value.
Calculations of 14N and 2H Nuclear Quadrupolar Coupling Constants for Liquid Ammonia
Authors: Laaksonen Aatto , Wasylishen Roderick E. 
Published: February 2015

Abstract
Nitrogen (14N) and deuterium (2H) nuclear quadrupolar coupling constants, ϰ(14N) and ϰ(2H), have been calculated for liquid ammonia at 197 K, 232 K, and 271 K, using a combination of molecular dynamics simulations and ab initio molecular orbital calculations. The basis set and cluster size dependence of the calculated results has been examined. The calculated value of ϰ(14N) for liquid ammonia at 197 K, -3.45 MHz, is found to be close to the accepted solid-state value. At 232 K and 271 K, the magnitudes of the calculated values are about 5 - 10% greater: -3.56 MHz and -3.67 MHz, respectively, but still well below the accepted gas-phase value, -4.09 MHz. The calculated values of ϰ (2H) for liquid ammonia are by about 20% smaller than the corresponding values calculated for the gas-phase monomer. On the basis of the calculations presented here and those of previous workers it is clear that the accepted experimental value of ϰ(2H) for solid ammonia-d3 is too small.
Self-Diffusion in Compressed Dimethylether: The Influence of Dipole-Dipole Interaction and Hydrogen Bonding Upon Translational Diffusivity in Simple Fluids
Authors: Heinrich-Schramm A. , Price W. E. , Lüdemann H.-D. 
Published: February 2015

Abstract
Self-diffusion coefficients of dimethylether have been measured as a function of temperature (185-458 K) and pressure (up to 200 MPa) by pulse-gradient field spin-echo NMR. Calculated activation volumes (ΔV*) fall from 15 (10-6 m3/mole) at the highest temperature to 7 (10-6 m3/mole) at the lowest. This trend is in keeping with values for other non-associating liquids. Comparison with self diffusion data for propane and ethanol reveals that the translational diffusivity in dimethylether is influenced by the substance's modest dipole moment (1.3 Debye). The effect is small but measur­able and becomes more pronounced at lower temperatures.
The Nature of the Mn Moment in Laves Phase Compounds: Evolution of the Magnetic Order in Ho1–xYxMn2
Authors: Ritte Clemens , Cywinski Robert , Kilcoyne Sue H. 
Published: February 2015

Abstract
Neutron powder diffraction has been used to study the evolution of long range magnetic order in the pseudobinary CI 5 Laves phase system Ho1-xYxMn2. Particular attention has been paid to the nature of the Mn moment. At Y-rich compositions (x > 0.9) an incommensurate antiferromagnetic structure, similar to that of YMn2 is observed. Transition to the ordered state, as in YMn2, is accompanied by a 5% expansion of the unit cell, identifying the Mn moments, of 2.7 μB, as intrinsic. The magnetic structure of compositions with x<0.7 resembles that of HoMn2 and DyMn2, with only one quarter of the chemically equivalent Mn sites possessing a moment of 0.6 μB induced by the local symmetry of the antiferromagnetically ordered Ho sublattice. Transition to the ordered state is not accompanied by a cell expansion. Between x = 0.7 and x = 0.9 there is no longe range magnetic order, nor is there an expansion of the unit cell, suggesting the total absence of either induced or intrinsic Mn moments. The results indicate that a critical Mn-Mn near neighbour distance of 2.663 Å is necessary to sustain an intrinsic Mn moment in these compounds.
A Study of the Distribution of Sodium Cations in the Zeolites NaX, NaY and ZnNaY Using Carbon Monoxide Adsorption and 23Na NMR Techniques
Authors: Seidel A. , Boddenberg B. 
Published: February 2015

Abstract
The zeolites NaX, NaY, Zn(55)NaY, and Zn(74)NaY were investigated by means of carbon monoxide adsorption and with static and magic angle spinning (MAS) 23Na NMR spectroscopy. The Na+ distribution between the sodalite (ß)- and supercages of the fully hydrated zeolites NaX and NaY were found to agree with XRD results. In the hydrated zinc-exchanged zeolites the Na+ ions almost exclusively populate the ß-cages.
The adsorption isotherms of CO in the dehydrated zeolites were analyzed quantitatively to yield the concentrations of Na+ residing in the supercages. The measured static and MAS 23Na NMR spectra were analyzed by comparing their widths and shapes with simulated central transition patterns and yield, inter alia, the concentrations of Na+ associated with the spectrum components. Arguments are put forward that 23Na NMR of dehydrated zeolites is well suited to distinguish Na+ cations in highly symmetric environments and mobile Na+ species from others located on general positions, but further resolution is hardly feasible.
The Anisotropy of the Molecular Reorientational Motions in Liquid Methanol
Authors: Ludwig R. , Bopp Ph. A. , Zeidler M. D. 
Published: February 2015

Abstract
Nuclear magnetic resonance (NMR) relaxation time measurements on isotopically substituted samples yield a detailed understanding of the molecular reorientational dynamics in liquids. Reorientational correlation times obtained from such experiments are reported for two molecule-fixed vectors in pure liquid methanol. While the reorientational motions of single molecules are nearly isotropic at temperatures below 250 K, at 308 K the reorientational correlation time of the O-H vector becomes 2.3 times larger than that of the O-C vector. Molecular dynamics (MD) simulations give access to the complete correlation functions of the reorientational motions. Correlation times extracted from these functions fit well to the experiment in case of the O-C vector. At low temperatures, however, these times lie markedly above those obtained in the experiment for the O-H vector. Thus, the simulation yields reorientation times for the O-H vector that are, independent of the temperature, twice as large as those of the O-C vector.
Beschleunigung des Stoffaustausches von Gas-Flüssigkeits-Reaktionen durch Schallwellen am Beispiel der Fetthärtung
Authors: Bartsch Achim 
Published: February 2015

Abstract
A method for increasing the mass transfer in gas/liquid-reactions by application of sonic vibration is described. The operating frequencies have been chosen such that the surfaces of the gas bubbles vibrate in resonance. At these operating frequencies (up to 1000 Hz), the damping of sound waves by the bubbly liquid is low, which is important in large-scale applications. Hydrogenation of soybean oil in a bubble column has been carried out as a test reaction. An increase in mass transfer from dispersed bubbles to the liquid in terms of kLaG of up to 36% has been effected by a relatively small amount of sonic power.
Einfluß der Molekülgröße auf Adsorptionsisothermen
Authors: Meyer C. , Hesse D. 
Published: February 2015

Abstract
Using methods of statistical thermodynamics, adsorption isotherms for the description of differ­ent-sized molecules are discussed by assuming the adsorbing surface to be energetically homoge­neous and by neglecting lateral interaction forces between the adsorbed particles. In this case, besides the temperature and the partial pressures, the adsorption process is mainly influenced by a geomet­rical interaction between the coadsorbed molecules which is modeled by a special parameter. Its value can be determined by geometrical considerations as well as by computer simulations.
Photosensitized Reduction of Carbon Dioxide in Solution Using Noble-Metal Clusters for Electron Transfer
Authors: Toshima Naoki , Yamaji Yumi , Teranishi Toshiharu , Yonezawa Tetsu 
Published: February 2015

Abstract
Carbon dioxide was reduced to methane by visible-light irradiation of a solution composed of tris(bipyridine)ruthenium(III) as photosensitizer, ethylenediaminetetraacetic acid disodium salt as sacrificial reagent, methyl viologen as electron relay, and a colloidal dispersion of polymer-protected noble-metal clusters, prepared by alcohol-reduction, as catalyst. Among the noble-metal clusters examined, Pt clusters showed the highest activity for the formation of methane as well as hydrogen. In order to improve the activity, oxidized clusters and bimetallic clusters were also applied. For example, the CH4 yield in 3-h irradiation increased from 51 x 10-3 μmol with unoxidized Pt clusters to 72 x 10-3 μmol with partially oxidized ones. In the case of Pt/Ru bimetalic systems, the improvement of the catalytic activity by air treatment was much greater than in case of monometallic clusters.
X-Ray Diffraction Study of the Solvation Structure of the Cobalt(II) Ion in N,N-Dimethylformamide Solution
Authors: Yokoyama Haruhiko , Suzuki Saeko , Goto Masuo , Shinozaki Kazuteru , Abe Yuriko , Ishiguro Shin-ichi 
Published: February 2015

Abstract
The solvation structure of Co2+ in N,N-dimethylformamide (DMF) has been studied by X-ray diffraction measurements on cobalt (II) and magnesium (II) Perchlorate solutions of the same concen­ tration, using an isostructural substitution method. The radial distribution function revealed three distinct peaks assigned to the oxygen, amido carbon (C1, and nitrogen atoms of six planar DMF molecules in the first coordination sphere around the metal atom. The distance from the cobalt atom to each atom (O, C1, N) is 213,299, and 423 pm, respectively. This indicates that the Co-O-C1 bond angle is 122-123° and the metal atom is close to the O-C1-N plane of the DMF molecule.
MD Simulation of Crystal Growth from Sodium Chloride Melt
Authors: Okada Isao , Nakashima Toshio , Takahagi Yukio , Habasaki Junko 
Published: February 2015

Abstract
Crystal growth on the (100) and (110) faces of sodium chloride from supercooled melt has been studied by molecular dynamics simulation. The growth velocity was considerably higher for the (100) plane (90-100 m/s) than for the (110) plane (transiently 40-50 m/s). Consequently, even from the (110) face, the crystal seems to grow in the [100] direction. Under the present MD conditions, ca. 2 interface layers with a considerable fraction of defects was formed, which means that the surface advances normal to itself without needing steps.
On the High Ionic Conductivity of Solid Solutions of Lithium Sulphate in Hexagonal Sodium Sulphate Na2SÒ4(I)
Authors: Lundén Arnold , Nilsson Leif 
Published: February 2015

Abstract
Solid solutions of Li2SO4 in the high-temperature phase Na2SO4 (I) have a much higher conductivity than expected. Diffusion and electromigration experiments show that both Li+ and Na+ ions are very mobile. It is concluded that the Li+ ions go into interstitial positions of the type (1/2,0,0), while vacancies are created in the Na+ lattice
Model Calculations of the Structure of Ni-Nb Metallic Glasses
Authors: Lamparter P. 
Published: February 2015

Abstract
The partial pair correlation functions of amorphous NixNb100-x alloys (x = 40, 50, 56, and 63) were simulated by computer modelling. A Cluster Relaxation procedure yielded reasonable agree­ ment with the experimental functions when non-additive pair potentials with preference for Ni-Nb atomic pairs were applied. With the use of the Reverse Monte Carlo method perfect agreement could be achieved. The impact of the chemical effect on the short range order is discussed by comparison with a statistical reference cluster. The analysis of the model clusters showed that the chemical short range order effect in amorphous Ni-Nb alloys, increasing with the Ni concentration, does not in­ volve specific stereochemical atomic arrangements. There is no correspondence to the short range order in crystalline Ni3Nb. The structure of Ni-Nb metallic glasses can be described as a polytetra-hedral packing with preferred hetero-coordination.
Thermodynamic Analysis of Isotope Effects on Triple Points and/or Melting Temperatures
Authors: Van Hook W. Alexander 
Published: February 2015

Àbstract
Available literature information on triple point or melting point isotope effects (and related physical properties) is subjected to thermodynamic analysis and consistency checks. New values for the melting point isotope effects for C6H6/CgD6 and c-C6H12/c-C6D12 are reported. 6Li/7Li melting point isotope effects reported recently by Hidaka and Lunden (Z. Naturforsch. 49 a, 475 (1994)) for various inorganic salts are questioned
The High-Frequency Rotational Spectrum of 1,1 -Dichloroethylene
Authors: Kisiel Z. , Pszczółkowski L. 
Published: February 2015

Abstract
The b-type rotational spectrum of 1,1-dichloroethylene was investigated up to 450 GHz and was found to be dominated by type-II R-type bands. All constants in the sextic Hamiltonian for the ground states of the common isotopic species and of the 37C1 isotopomer were determined from measurements on transitions with J up to 95. Quartic and sextic planarity defects were evaluated and are compared and discussed with those for several recently investigated planar molecules
Rotational Tunnelling in Binary Tetramethylmetal Mixtures
Authors: Prager Michael , Zhang Da , Weiss Al. 
Published: February 2015

Abstract
Mixed PbcSn1-c(CH3)4 samples with c = 0.0, 0.1, 0.2,0.25, 0.48, 0.5, 0.75,0.85, and 1.0 and mixed [Pb(CH3)4](.[Sn(CD3)4]1-c. samples with c = 0.02 and 0.09 were investigated by high resolution inelastic neutron scattering. Rotational tunnelling transitions are observed for energy transfers hω<100 μeV. The global features are interpreted in a single particle model. A strong matrix effect of the Pb component is attributed to changes of potential symmetry. Effects beyond the expectation of the single particle description are found
Critical Curves and Phase Equilibria of Binary Methanol-Systems for High Pressures and Temperatures
Authors: Neichel M. , Franck E.U. 
Published: February 2015

Abstract
The critical curves of binary systems of methanol combined with CH4, N2, H2, CO and CO2 have been determined experimentally up to 100 MPa and higher by Brunner. In the present work a rational equation of state of the perturbation type with a repulsion and an attraction term has been applied to reproduce these critical curves up to high pressures. A square well potential for intermolecular interaction is used. With pairwise combination rules for these potentials three adjustable parameters are needed. Values for these parameters, obtained from the fitting of the critical curves are used to calculate isotherms of the two-phase high pressure equilibrium surfaces for the four systems of methanol combined with CH4, N2, H2, and CO. Three of these have not yet been investigated experimentally. It is suggested to use this procedure for predictions of the extent of three-dimensional two-phase regions in temperature-pressure-composition spaces
Ion-Ion De-Association and Association of Strong Electrolytes at High Dilution from Nuclear Magnetic Relaxation Measurements
Authors: Detscher E. , Hertz H. G. , Holz M. , Mao Xi-an 
Published: February 2015

Abstract
Proton magnetic relaxation rates in the system N(CH)3)4Br/NiBr2/D2O, N(CH3)4Br/MnBr2/ D2O, Ni(00CCH3)2/D2O and Mn(00CCH3)2/D2O have been measured as a function of the solute concentration in the range 0.002 < c* ⪍ 1 m. Division by the concentration c* and by a quantity characterizing the ionic motion yields the association parameter (4-parameter). A decreases and increases with decreasing concentration for the systems involving cation-cation and cation-anion interaction, respectively. The relaxation rates of 35C1-, 133Cs+ , and 25Mg++ in diamagnetic aqueous solutions have also been measured down to high dilution. Here as well in most cases we have found an increase of the A-parameter with decreasing salt concentration, indicating ion-ion association at high dilution. A comparison with the results of the Debye-Hückel theory is given; there is qualitative agreement. Our experimental results for 35C1- generally do not support theoretical considerations in the literature, where a Cl--Cl- association was postulated
Cluster Formation in Liquid Lithium Niobate A Small Angle X-ray Scattering Investigation
Authors: Andonov P. , Kimura S. , Kobayashi A. 
Published: February 2015

T
Structural analysis of the clustering phenomenon in the LiNbO3 melt was carried out by means of small-angle X-ray scattering using synchrotron radiation in the range of momentum transfer 0.2 nm-1 ≤ k ≤ 14.0 nm-1. Microclusters were present in the melt throughout the entire explored temperature-domain from 1673 K to 1513 K which includes undercooling (melting point 1526 K). The radius of gyration, size, shape and distance of particles were determined. Chains of few NbO6 octahedra and small blocks constituted by two layers of four corner-shared octahedra, interlocked by a lithium atom, could be good models for the microclusters in a large temperature-domain. By lowering the temperature, the particle size increased. Below 1553 K, probable macroclusters would be correlated to the rapid increase of the viscosity. Using the viscosity data and previously published and the present SAXS results, it was possible to evaluate the volume of the clusters. Near the freezing point about a quarter of the volume would be occupied by clusters.
EPR Study of Cr5+ and Cu2+ in Some Zeolites Introduced by Solid- and Liquid-State Reactions
Authors: Köksal Fevzi , Ucun Fatih , Kartal İbrahim 
Published: February 2015

Abstract
This study reports on the EPR of Cr5+ and Cu2+ ions, introduced by solid- and liquid-state reactions with the synthetic zeolites 3A, 4A and 5A, and the natural zeolite clinoptilolite. Cr3+ was oxidized to Cr5+ in the samples, the coordination around Cr5+ being square pyramidal. Super-hyperfine (shf) interaction of Cr5+ with 27Al nucleus was observed in both solid-and liquid-state-introduced 5A zeolite, whereas this shf could not be observed for the solid-state introduced 4A zeolite. The liquid-state Cr-introduced 4A zeolite needed a heat treatment at 473 K for ½ h for the appearance of shfs. Furthermore, it has been found that the coordination structure around the Cu2+ is square pyramidal in solid-state introduced samples, whereas it is octahedral in the liquid-state introduced ones.
ESR Spectrum and Magnetic Behavior of Copper(II) Sebacate
Authors: Lezama L. , Rojo T. , Baran E. J. , Torre M. H. 
Published: February 2015

Abstract
The magnetic susceptibility of copper(II) sebacate, measured between 5 and 400 K, confirms the presence of strongly coupled Cu-Cu pairs. The ESR spectrum, obtained with a polycrystalline sample, shows an important rhombic anisotropy and supports a dx2-y2 ground-state.