bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Maximum Number of Kekule Structures of Cata-condensed Polyhexes
Authors: Hansen Pierre , Zheng Maolin 
Published: February 2015

Abstract
Let H denote a simply-connected cata-condensed polyhex. It is shown that if H has three hexagons in a row it does not have a maximum number of Kekulé structures. Otherwise, its number of Kekulé structures is equal to its number of sets of disjoint hexagons (including the empty set). These results lead to an efficient algorithm to determine simply-connected cata-condensed polyhexes with a maximum number of Kekulé structures. A table of such values of H with up to 100 hexagons is provided.
Nonintegrable Stadium Billiard seen as Mirror Cabinet
Authors: Kruelle C. A. , Kittel A. , Huebener R. P. 
Published: February 2015

Abstract
The Bunimovich stadium billiard is treated as a mirror cabinet seen from inside. The resulting system of virtual images of the mirror walls reveals a fractional structure which corresponds to the chaotic trajectories of light rays or billiard balls inside the stadium.
Diode Laser Spectroscopy of NaD, KD, RbD, and CsD: Determination of the Mass Independent Parameters and Mass Scaling Coefficients of the Alkali Metal Hydrides
Authors: Essig Kay , Urban Rolf-Dieter , Birk Helmut , Jones Harold 
Published: February 2015

Abstract
The infrared spectrum of the monodeuterides of the alkali metals, sodium, potassium, rubidium, and cesium have been measured with a nominal accuracy of ±0.001 cm-1 using a diode laser spectrometer. Spectral lines of both the fundamental and the first hot band were observed for all the deuterides except RbD where only the fundamental was measured. The accuracy of previously published data on KH was also improved.
Combination of these new data with similar results obtained previously for the equivalent monohydrides allowed the determination of a set of mass-independent parameters and mass-scaling coefficients for the hydrides of all of the alkali metals. This has allowed the relative magnitudes of the parameters to be compared for the first time. The results indicate that non-adiabatic effects are most prevalent in CsH.
Inversion of First Kind Volterra Equations: Back to Direct Methods?
Authors: Bilbao Luis E. , Grondona Diana E. 
Published: February 2015

Abstract
Numerical inversion of the first kind Volterra equation (the Abel inversion included) has been extensively studied. Direct methods were probably the first methods used to attempt the inversion. Together with the computer hardware evolution, new methods were devised in order to deal with the inherent problem of this kind of equation, that is, error magnification. Using a large number of data points (several thousands) most methods are difficult to use, specially when the inversion and its error are required on line, that is, while performing the experiments. Further, error propagation (coming from the input data and from the parameters of the problem) is, usually, a difficult task and has not been extensively studied. On the other hand, direct methods together with an adequate filter give good resolution, are fast, and error propagation is easily performed. In this work we used the so called Matrix Method for inverting three different equations, showing how to build the resolvent nucleus and how errors propagate through the solution.
Isomerization of Diphenyl Polyenes. Part VII. The effect of Daylight and Direct Irradiation on the Photoisomerization of Ph-(CH = CH)n-Ph for n = 2, 3, 4 in Poly(vinyl alcohol) Films
Authors: Kawski A. , Kukliński B. , Kubicki A. 
Published: February 2015

Abstract
Photoisomerization of 1,4-diphenyl-1,3-butadiene (DPB), 1,6-diphenyl-1,3,5-hexatriene (DPH) and 1,8-diphenyl-1,3,5,7-octatetraene (DPO) in poly(vinyl alcohol) (PVA) films was studied unter daylight and direct irradiation. The most efficient photoisomerization occurs in the DPB molecule, the smallest among the compounds investigated. For the greatest, DPO, molecule no distinct isomerization was observed in daylight and only a temperature effect was noted. Therefore, the DPO molecule in the PVA film heated to 423 K may serve as a fluorescence standard.
Internal Cation Mobilities in the Molten Systems (Ag, Rb)NO3 and (Ag,Cs)NO3 Remeasured by the Klemm Method
Authors: Chou Pao-hwa , Matsuura Haruaki , Okada Isao 
Published: February 2015

Abstract
Internal mobility ratios in the molten binary systems (Ag,Rb)NO3 and (Ag,Cs)NO3 have been measured by Klemm's countercurrent electromigration method at various temperatures and compositions. From these and the available data on the densities and conductivities, the cation internal mobilities b have been calculated. Over the investigated regions of temperature and composition bAg is greater than bRb and bCs . The internal mobility of Ag+ is well expressed by bAg = [A/(V - V0)] • exp(-E/RT), where V is the molar volume of the mixtures, A, V0 , and E being constants nearly independent of the coions. A comparison of the present data with those previously obtained by the EMF method certifies that the Klemm method yields more precise data.
33S Nuclear Hyperfine Structure in the Rotational Spectrum of Thiazole
Authors: Kretschmer U. , Dreizler H. 
Published: February 2015

Abstract
We investigated the 33S nuclear quadrupole coupling of thiazole- 33S in natural abundance by molecular beam Fourier transform microwave spectroscopy. In addition the 14N nuclear quadrupole coupling could be analyzed with high precision. We derived the rotational constants A = 8529.29268 (70) MHz, B = 5427.47098 MHz, and C = 3315.21676 (26) MHz, quartic centrifugal distortion constants and the quadrupole coupling constants of 33S χaa = 7.1708 (61) MHz and χbb= -26.1749 (69) MHz and of 14N χ aa = -2.7411 (61) MHz and χbb = 0.0767 (69) MHz.
Internal Cation Mobilities in the Molten Binary Systems (Li, Na)Cl and (Na, K)Cl
Authors: Yang Chao-Cheng , Lee Bor-Jih 
Published: February 2015

Abstract
Internal mobility ratios of the two cations in the molten binary systems (Li, Na)Cl and (Na, K)Cl have been measured with Klemm's column method. From these and available data on the densities and conductivities the internal mobilities bLi , bNa and bK have been calculated. In (Li, Na)Cl, bLi is smaller than bNa in the investigated composition and temperature range, and in (Na, K)Cl, the Chemla effect occurs, that is a crossing of the isotherms is observed.
The internal cation mobilities bM are well expressed by the empirical relation
bM = [A/(V-V0)]exp(-E/RT),
where A, E and V0 are constants depending on the cation M and V is the molar volume of the mixture.
Dielectric Relaxation of Liquid Polyethyleneglycol on Addition of Polyvinylpyrrolidone
Authors: Stockhausen M. , Abd-El-Rehim M. 
Published: February 2015

Abstract
The set of relaxation times describing the dynamic dielectric properties of liquid polyethyleneglycol 200 at 20 and 40 °C is found to be practically independent of the admixture of polyvinylpyrrolidone, though the viscosity is appreciably increased. This is compared to the rather similar behaviour of small molecular solvents.
The Room Temperature Dielectric Spectrum of 2,2-Dimethyl-1 -butanol
Authors: Edelmann R. , Würflinger A. , Hornhardt S. v. , Stockhausen M. 
Published: February 2015

Abstract
The dielectric spectrum of the title substance ('neohexanol') in its pure liquid state is reported for 293 K up to 71 GHz and, for a restricted frequency range, also for lower temperatures (down to 253 K). The room temperature spectrum resembles that of alicyclic alcohols, in particular cyclopentanol, with respect to spectral shape, main relaxation time and the relation of the latter to viscosity, which similarity may be connected with the fact that these alcohols are able to form 'plastic crystals'.
Magnetischer Circular Dichroismus (MCD) von cyclischen π-Elektronensystemen mit 4N±1 Elektronen
Authors: Kramer B. , Fleischhauer J. 
Published: February 2015

Abstract
The theory of the magnetic circular dichroism (MCD) of cyclic re-electron systems with 4 N ± 1 electrons, such as the radical anion of [16] annulene, has been investigated in the perimeter model approximation. General solutions and formulas for the calculation of the Faraday parameters A, B, and C are derived analytically. The calculated and measured spectra of the 17 π-electron [16] annulene radical are in good agreement.
Comments Concerning "The Effect of Temperature on the Fluorescence Quenching of Perylene by Tetrachloromethane in Mixtures with Cyclohexane and Benzene"
Authors: Acree William E. 
Published: February 2015

Abstract
An indirect spectrofluorometric probe method is developed for calculating equilibrium constants for formation of heterogeneous solvent-solvent molecular complexes from measured fluorescence emission intensities in select systems that exhibit parabolic-shaped Stern-Volmer quenching plots.
Nonlinear Behavior of Circularly Polarized Laser Beams Propagating through Sodium Vapor
Authors: Röhricht B. , Eschle P. , Dangel S. , Holzner R. 
Published: February 2015

Abstract
A variety of surprising effects arise from the nonlinear light-matter interaction of circularly polarized laser light propagating through sodium vapor. We present experimental evidence for an asymmetry in the absorption of left hand and right hand circularly polarized light as well as for the creation of a collimated light beam of apposite polarization within the light-matter interaction region. Both effects are not yet explained by common theories.
Anomalous Frequency Scaling of a Saddle-Node Bifurcation on a Limit Cycle Disclosed in a Semiconductor Experiment
Authors: Richter R. , Kittel A. , Parisi J. 
Published: February 2015

Abstract
During low-temperature impact ionization breakdown in extrinsic germanium, spontaneous current and voltage oscillations can be observed. The onset of periodic oscillatory behavior is governed by a saddle-node bifurcation on a limit cycle. Besides the well-known square-root law of control parameter dependence, we find a different scaling in the vicinity of the bifurcation point. Such anomalous behavior is reproduced by a simple model approach.
Explicit Realization of Chaos Control in an NMR-Laser Experiment
Authors: Parisi J. , Badii R. , Brun E. , Flepp L. , Reyl C. , Stoop R. , Rössler O. E. , Kittel A. , Richter R. 
Published: February 2015

Abstract
The usefulness of the Ott-Grebogi-Yorke control method is demonstrated by stabilizing a chaotic NMR-laser system around an unstable period-one orbit. We have used a six-dimensional delay-coordinate embedding technique in order to fully determine the stability properties of the orbit controlled. Our analysis yields small time-dependent perturbations of the system quality factor capable to perform real-time control.
Ab initio Study of the Electric Field Gradients in SCl2
Authors: Wang Jiahu , Smith Vedene H 
Published: February 2015

Abstract
The electric field gradients (EFG) in SCl2 have been computed with both self-consistent-field (SCF) and configuration-interaction (Cl) methods. The predicted EFG, along with the nuclear quadrupole moment QN of 35Cl and 37Cl from other sources, allows us to compare theoretical quadrupole coupling constants with new experimental results. The best values obtained agree with the experiment within 3%. It has been found that the principal axis of the coupling tensor does not coincide with the S-Cl internuclear axis, and the tilt angle has been predicted close to that from experiment.
About the Usage of Scaling Parameters in the Scaled Particle Theory of Mixtures of Non-Additive Hard Spheres
Authors: Schaink H. M. 
Published: February 2015

Abstract
A new simple equation of state is derived for symmetric and asymmetric mixtures of non-additive hard spheres. The derivation of the equation of state is reminiscent of the scaled particle theory. However, this method uses two scaling parameters, which depend on the composition of the mixture. As a result, the equation of state presented here approaches in a natural way the limit of the one component fluid. This feature of the present theory stands in sharp contrast to common scaled particle theories for non-additive hard spheres, where the one component limit has an unphysical dependence on the non-additivity. The equation of state can be used for mixtures of particles that differ in size and has a second and a third virial coefficient which are exact up to first order in the non-additivity. The compressibility factors and the demixing densities predicted by the present equation of state are in fairly good agreement which available MC data.
Eine Anmerkung zum langwelligen UV-Übergang in alternierenden und dazu isomeren nichtalternierenden polycyclischen aromatischen Kohlenwasserstoffen
Authors: Zander Maximilian , Friedrichsen Willy 
Published: February 2015

Abstract
Based on the HMO formalism and for an infinite number of carbon centers an analytical solution for the ratio x = ∆ε(HOMO-LUMO)[NAH]/∆c(HOMO-LUMO)[AH] of nonalternant polycyclic aromatic hydrocarbons (NAH) and its respective counterparts (AH) is given. It is shown that generally x ≥ 1, which is in agreement with experimental observations.
Externally Driven Nonlinear Oscillator, PainlevéTest, First Integrals and Lie Symmetries
Authors: Steeb W.-H. , Euler N. 
Published: February 2015

Abstract
For arbitrary constants c1 , c2 and an arbitrary smooth functions f the driven anharmonic oscillator d2u/dt2+c1du/dt + c2u + u3 =f(t) cannot be solved in closed form. We apply the Painleve test to obtain the constraint on the constants c1 , c2 and the function f for which the equation passes the test. We also give the Lie symmetry vector field and first integrals for this equation
Small Oscillations, Sturm Sequences, and Orthogonal Polynomials
Authors: Baake Michael 
Published: February 2015

Abstract
The relation between small oscillations of one-dimensional mechanical n-particle systems and the theory of orthogonal polynomials is investigated. It is shown how the polynomials provide a natural tool to determine the eigenfrequencies and eigencoordinates completely, where the existence of a specific two-termed recurrence formula is essential. Physical and mathematical statements are formulated in terms of the recurrence coefficients which can directly be obtained from the corresponding secular equation. Several results on Sturm sequences and orthogonal polynomials are presented with respect to the treatment of small oscillations. The relation to the numerical treatment of the generalized eigenvalue problem is discussed and further applications to physical problems from quantum mechanics, statistical mechanics, and spin systems are briefly outlined.
A Simplified Algorithm for Finding Partially Invariant Solutions of Quasilinear Systems
Authors: Becker Dirk-A. 
Published: February 2015

Abstract
The method of partially invariant solutions of PDE systems was introduced by Ovsiannikov as a generalization of the classical similarity analysis. It offers a possibility to calculate exact solutions possessing a higher degree of freedom than similarity solutions. Ovsiannikov's algorithm, however, is somewhat hard to apply because one has to deal with three equation systems derived from the original PDE system. By means of the two-dimensional Euler equations, we show how the algorithm can be essentially simplified if classical similarity solutions are already known. Further, we prove a necessary criterion for the simplified algorithm to be senseful.
Ultrasonic Velocity and Absorption in(Li,Ag)NO3, (Na,Ag)NO3,(K,Ag)NO3, (Cs,Ag)NO3, (Li,Rb)NO3, and (Na,Rb)NO3 Melts Measured by the Pulse Transmission Method
Authors: Rejek E. , Richter J. , Stark A. , Vogt M. 
Published: February 2015

Abstract
Ultrasonic velocity and absorption have been measured in molten (Li,Ag)NO3, (Na,Ag)NO3, (K ,Ag)NO3, (Cs,Ag)NO3, (Li,Rb)NO3, and (Na ,Rb)NO3 , and (Na,Rb)NO3 as functions of composition in the tem­perature range 230 to 300 °C. An improved pulse transmission device was applied. The obtained accuracy was 2‰o for the velocity and 2-4% for the absorption data. The ultrasonic velocity and absorption coefficient (25 MHz) were found to depend linearly on temperature. The dependence of the velocity on the mole fraction could be represented by a cubic polynomial. For the absorption values (referred to the square of frequency) a reasonable general dependence on composition could not be given. The adiabatic compressibility of all mixtures has been calculated from the measured sound velocity. The ratio bulk/shear viscosity and the bulk viscosity itself follow from the measured absorption values together with the velocity values. The conclusion from these data is that ultrasonic absorption in the six investigated systems is governed by the bulk viscosity and that structural rearrangements rather than structural relaxation of the molecules, are the reason for high bulk viscosities in ionic melts.
Flash Photolysis Studies of 4-Chloroanisole in Aqueous Solution
Authors: Abd El-Hameed Faten S. M. , Krajnik Paul , Getoff Nikola 
Published: February 2015

Abstract
The photoinduced formation of transients in aqueous 4-chloroanisole (4 ClA), at pH 7 and 9, were studied by conventional flash photolysis. The absorption spectra of various transients in airfree as well as in aqueous solutions saturated with N2O , air or pure oxygen, are presented and discussed.
Effective Boson-Fermion Dynamics for Subfermion Models
Authors: Grimm G. 
Published: February 2015

Abstract
Effective composite particle dynamics can be derived by weak mapping of quantum fields. This method was already applied to derive effective boson or boson-fermion coupling theories from a nonlinear subfermion field. In this paper we present an extension of those calculations to the general group theoretical treatm ent of two-fermion bound states and their coupling to (elementary) fermions within an arbitrary nonlinear spinor-isospinor field model. The resulting effective field equations are com pared with the corresponding phenomenological expressions which for example underly the standard electroweak theory.
PACS 11 .10 - Field theory.
PACS 12.10 - Unified field theories and models.
PACS 12.35 - Composite models of particles.
Anharmonic Self-Consistent Theory of Crystals. II. The 2d and 3d Quartic Crystal Models
Authors: Soulayman S. Sh. , Marti C. Ch. , Guilpin Ch. Ch. 
Published: February 2015

Abstract
In this paper we apply the method developed in part I for describing the crystalline state of two and three dimensional inert gases. For strong anharmonicity of fourth order, the equations of state of these gases are obtained. This way we calculate the thermoelastic properties of two and three dimensional argon, krypton and xenon using the Lennard-Jones potential. The corrections to the Helmholtz free energy and thermodynamic properties due to quantum effects are considered. The results are compared with the available experimental data.
35Cl Nuclear Quadrupole Relaxation in Antimony Trichloride
Authors: Okubo Noriaki , Abe Yoshihito 
Published: February 2015

Abstract
The 35Cl NQR frequency and spin-lattice relaxation time in SbCl3 have been measured between 10 K and the melting point. The relaxation at low temperatures is attributed to the Raman process. A Debye temperature of 141 K and covalencies 0.390 and 0.356 are obtained. The latter values correspond well to those obtained from the NQR frequencies. For the relaxation above 200 K two more mechanisms are considered.
Nuclear Quadrupole Resonance of Antimony in Ln3Sb5O12 Crystals
Authors: Raevsky A. M. , Gukalova A. G. , Semin G. K. 
Published: February 2015

Abstract
Complete 121,123Sb NQR spectra of crystalline rate earth antimonites Ln3Sb5O12 (Ln = La, Nd, Er, Lu) were recorded at 77 K. The quadrupole coupling constants and asymmetry parameters of the electric field gradient were measured. A “lanthanide compression” effect on the antimony NQR was observed. Using relations found for the antimonites under study, the Sb spectral parameters of other lanthanide compounds can be predicted.
Internal Cation Mobilities in Molten (Ca,Ba)Cl2
Authors: Matsuura Haruaki , Okada Isao 
Published: February 2015

Abstract
Internal cation mobility ratios in molten (Ca, Ba)Cl2 have been measured by the Klemm method for χBa (mole fraction of barium chloride) = 0.25 -0.51 at 973 K and χBa = 0 -0.61 at 1073 K. From these and available data on the densities and conductivities the internal cation mobilities b have been calculated, assuming additivity of the molar volume. Although bCa in pure CaCl2 is greater than bBa in pure BaCl2, bCa is smaller than bBa in all the investigated mixtures at the respective temperatures. With increasing molar volume at constant temperature both bCa and bBa decrease. Since the profile of the isotherms is similar to that for the binary monovalent chloride systems so far studied, monoatomic ionic species are assumed to carry the current also in the alkaline earth chloride melts.
The Dielectric and Dilatometric Single Crystal Studies of Phase Transitions in a New Member of Family of Halogenoantimonates(III) [C(NH2)3l2SbCl5· [C(NH2)3]Cl
Authors: Zaleski J. , Jakubas R. 
Published: February 2015

Abstract
The results of dielectric, dilatometric and DSC studies on a new member of the family of alkylammonium halogenoantimonates ([(C(NH2)3]2SbCl5 • [(C(NH2)3]Cl) are presented. This compound undergoes three phase transitions at 146 K, 162 K, and 366 K. The two low temperature transitions are suggested to be of the displacive type and the high temperature one of the order-disorder type. The character of temperature changes of the electric permittivity at the lowest temperature transition suggest a polar phase below the transition temperature.
The Topological Entropy for an Inclined Billiard in a Gravitational Field
Authors: Vollmer Jürgen 
Published: February 2015

Abstract
A new parameterization for an inclined billiard initially discussed by Hénon is presented. This parameterization expresses the time evolution of the scattering system by a family of pruned baker transformations. This allows to make contact with recent work on these mappings. As an applica­tion, the topological entropy is analytically derived in a very good approximation and it is indicated how to systematically improve the result. The result which contains no free parameter, agrees excellently with numerical data for the whole parameter range from strongly chaotic scattering described by a complete symbolic dynamics to a bounded system with trivial scattering behavior. 05.45. + b, 03.20. + i, 05.90. + m
The ‘Triptych Fractal’ -A New Feature of the Logistic M ap
Authors: Richter R. , Kruelle C. A. , Kittel A. , Rössler O. E. 
Published: February 2015

Abstract
The recently introduced path length method for nondissipative systems is generalized to dissipa­tive systems, specifically, the logistic map. A new prototype fractal is found to underlie the resulting nowhere-differentiable structure ("triptych principle").
β-Radiation Detected NMR in Solid and Liquid Neon
Authors: Hilmer F. , Schirmer A. , Ackermann H. , Heitjans P. , Stöckmann H.-J. 
Published: February 2015

Abstract
Spin-polarized β-active 23Ne (T1/2 = 37.2s) nuclei were created by capture of polarized cold neutrons in solid and liquid neon. The angular asymmetry of the β-radiation was used to monitor the nuclear polarization. From nuclear magnetic resonance curves the value for the dipole moment |μ(23Ne)| = 1.079(1) n.m. (uncorrected) was obtained which is more precise than the literature value. Comparing the measured spin-lattice relaxation rates with those of stable 21Ne the nuclear quadru­pole moment of 23N e was determined. It agrees with a shell model calculation. The feasibility of 23Ne-β-NMR for investigations in condensed rare gases in demonstrated.
1H -14N Nuclear Quadrupole Double Resonance with Multiple Frequency Sweeps
Authors: Seliger J. , Žagar V. , Blinc R. 
Published: February 2015

Abstract
A new highly sensitive 1H -14N nuclear quadrupole double resonance technique is presented which is based on magnetic field cycling and on the application of multiple frequency sweeps of an r.f. magnetic field. The sensitivity and the resolution o f the new technique are estimated. Some experimental results obtained by the new technique are presented.