bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Kinetics of Catalytic Reactions Studied by Resistivity Measurements on Thin Metal Films
Authors: Finzel H.-U. , Heping Bi , Wissmann P. 
Published: February 2015

Abstract
Resistivity measurements on thin films are very suitable for the study of the kinetics of reactions on metallic surfaces. The oxidation of carbon monoxide on palladium is investigated as an example of great technical relevance, where details of the reaction mechanism and the film structure are well-known from literature. The time dependence of the change in resistivity is quantitatively interpreted with the help of a diffusion model based on a Monte-Carlo simulation of the gas coverage of the surface.
Structure of Molten Mn74Si26 and Molten Mn33.5Si66.5 by Neutron Diffraction
Authors: Sedelmeyer B. , Lamparter P. , Steeb S. 
Published: February 2015

Abstract
Molten Mn74Si26 and molten Mn33.5Si66.5 were investigated by neutron diffraction. The pair correlation function yielded, together with the X-ray results from a former paper, the partial coordination numbers, atomic distances, and the short range order parameter with the result that the atomic distribution in molten Mn33.5Si66.5 is statistical while the structure factor of molten Mn74Si26 , as obtained with neutrons, shows a strong prepeak which means rather strong compound formation.
The Blue Bottle Experiment and Pattern Formation in this System
Authors: Adamčíková L’. , Ševčík P. 
Published: February 2015

Abstract
The methylene blue - saccharide - NaOH system, the so-called “Blue Bottle” experiment was investigated. When this system is poured into an open petri dish, spatial structures start to generate after an induction period. The induction period increases in the order of xylose < glucose < galactose < arabinose < mannose.
A Set of Atom-in-Molecule Polarizability Increments Derived by Means of the MINDO/3-FP Method
Authors: Raabe Gerhard , Zobel Elke , Kock Rüdiger , Souren Jürgen Peter 
Published: February 2015

Abstract
In continuation of earlier work, a set of 90 non-cyclic organic compounds was used to determine atom-in-molecule polarizability increments employing Metzger’s combination of the semiempirical MINDO/3-FP method and a partitioning of the molecular dipole moment. The group contained alcohols, ethers, amines, amides, and carboxylic acids. More than one hundred arbitrarily chosen molecules were then used to evaluate the new set of increments. This set of compounds does not overlap with the one used to derive the increments. The molecular polarizabilities calculated employ-ing the increments were found to correlate nicely with the corresponding “experimental” values determined by means of the Lorenz-Lorentz equation. Thus, the atomic increments together with the correlation equation provide access to polarizabilities which might for example be used to calculate the dispersion-and induction contributions to the lattice energies of organic molecular crystals.
Dielectric Spectroscopy of Binary Liquid Mixtures of Methanol with Morpholine, Pyrrolidine and some of their Derivatives
Authors: Syal V. K. , Becker U. , Elsebrock R. , Stockhausen M. 
Published: February 2015

Abstract
Dielectric spectra (up to 72 GHz) have been measured at 20 °C for mixtures of methanol and one of the following substances: morpholine, N-methyl morpholine, N-cyano morpholine, pyrrolidine and N-cyano pyrrolidine. The composition dependence of the relaxation parameters shows close similarities for the morpholines and, on the other hand, for the pyrrolidines, which indicates that a structure breaking effect on methanol is exerted by the former but not by the latter group of substances.
Three-body Effects in Calcium(II)-ammonia Solutions: Molecular Dynamics Simulations
Authors: Sidhisoradej Wiwat , Hannongbua Supot , Ruffolo David 
Published: February 2015

Abstract
Molecular dynamics simulations have been performed with and without three-body corrections at an average temperature of 240 K using a flexible ammonia model. The system consists of one calcium ion and 215 ammonia molecules. The calcium(II)-ammonia interactions were newly developed, based on ab initio calculations with a basis set of double zeta quality. The role of three-body interactions on the structural and dynamical properties of the solution has been investigated. The presence of three-body corrections leads to the reduction of the first shell coordination number of Ca(II) in liquid ammonia from 9 to 8, the increase of the size of the solvation shell by 0.33 A and the disappearance of the sec-ond solvation shell.
Nonlinear Electrohydrodynamic Stability of Two Superposed Bounded Fluids in the Presence of Interfacial Surface Charges
Authors: El-Sayed M. F. , Callebaut D. K. 
Published: February 2015

Abstract
The method of multiple scales is used to analyse the nonlinear propagation of waves on the interface between two superposed dielectric fluids with uniform depths in the presence of a normal electric field, taking into account the interfacial surface charges. The evolution of the amplitude for travelling waves is governed by a nonlinear Schrödinger equation which gives the criterion for modulational instability. Numerical results are given in graphical form, and some limiting cases are recovered. Three cases, in the pure hydrodynamical case, depending on whether the depth of the lower fluid is equal to or greater than or smaller than the one of the upper fluid are considered, and the effect of the electric field on the stability regions is determined. It is found that the effect of the electric field is the same in all the cases for small values of the field, and there is a value of the electric field after which the effect differs from case to case. It is also found that the effect of the electric field is stronger in the case where the depth of the lower fluid is larger than the one of the upper fluid. On the other hand, the evolution of the am-plitude for standing waves near the cut-off wavenumber is governed by another type of nonlinear Schrödinger equation with the roles of time and space are interchanged. This equation makes it possible to determine the nonlinear dispersion relation, and the nonlinear effect on the cut-off wavenumber.
PVT Measurements on 4'-w-Hexyl-Biphenyl-4-Carbonitrile (6CB) and 4'-w-Heptyl-Biphenyl-4-Carbonitrile (7CB) up to 300 MPa
Authors: Sandmann M. , Würflinger A. 
Published: February 2015

Abstract
P, Vm , T data were established for 4'-n-hexyl-biphenyl-4-carbonitrile (6CB) and 4'-n-heptyl-biphenyl-4-carbonitrile (7CB) between 300 and 370 K up to 300 MPa, and specific volumes were determined for the liquid crystalline, isotropic, and also partly for the crystal phases. Volume and enthalpy changes at the phase transitions are also presented. In the case of 6CB, a new crystal phase has been detected, corresponding to a triple point at 338 K and 196 MPa. The p, Vm , T data enabled us to separate the entropy change into a volume-dependent part and configurational part. From the molar volumes along the nematic-isotropic phase transition TNl(p), the molecular field parameter γ=∂lnTNI/∂lnVNI was determined.
An X-ray Diffraction and Mössbauer Spectroscopy Study of the Reaction between Hematite and Aluminum Activated by Ball Milling
Authors: Concas Giorgio , Corrias Anna , Manca Enrico , Marongiu Giaime , Paschina Giorgio , Spano Giorgio 
Published: February 2015

Abstract
The reaction between hematite and aluminum in presence of allumina as diluent activated by Ball Milling powder mixtures in different energetic conditions has been investigated. To this purpose, the powders at different milling times have been characterized by X-ray Diffraction and Mössbauer Spectroscopy. A self-substained combustion reaction was observed when the strongest energetic conditions of milling were adopted. The intermediate products of the reaction also depend on the energetic conditions: the formation of hercynite is favoured by the use of strong energetic conditions while the formation of an Fe-Al alloy was observed when a low energy per single hit is transferred to the powders.
Electron Paramagnetic Resonance and DTA Investigation of Cr3+ in Tris(guanidinium) Hexafluoroaluminate Single Crystals
Authors: Lakshmi Kasturi T. , Krishnan V. G. 
Published: February 2015

Abstract
Electron Paramagnetic Resonance (EPR) studies of Cr 3+ in single crystals of tris(guanidinium) hexafluoroaluminate, [C(NH2)3]3 AlF6 , have been carried out in the X-band region. A temperature dependent study of the zero-field splitting parameter D in the range 77-398 K shows the presence of a phase transition, which is supported by Differential Thermal Analysis. In addition, 19F superhyperfine struc-ture has been observed in the 9.3% naturally abundant 53Cr isotope hyperfine structure. D shows a large decrease with increasing temperature. The phase transition brings about a chemical inequivalence in the two chemically equivalent but magnetically inequivalent room temperature (CrF6)3- species. Compar-ison is made with the alums AlCl3 • 6H20, as well as other guanidinium aluminum salts.
Extended Painlevé Expansion, Nonstandard Truncation and Special Reductions of Nonlinear Evolution Equations
Authors: Lou Sen-yue 
Published: February 2015

Abstract
To study a nonlinear partial differential equation (PDE), the Painleve expansion developed by Weiss, Tabor and Carnevale (WTC) is one of the most powerful methods. In this paper, using any singular manifold, the expansion series in the usual Painleve analysis is shown to be resummable in some different ways. A simple nonstandard truncated expansion with a quite universal reduction function is used for many nonlinear integrable and nonintegrable PDEs such as the Burgers, Korteweg de-Vries (KdV), Kadomtsev-Petviashvli (KP), Caudrey-Dodd-Gibbon-Sawada-Kortera (CDGSK), Nonlinear Schrödinger (NLS), Davey-Stewartson (DS), Broer-Kaup (BK), KdV-Burgers (KdVB), λf4 , sine-Gordon (sG) etc.
Atomic Structure of Rare Earth Si-Al-O-N Glasses
Authors: Uhlig H. , Hoffmann M.-J. , Steeb S. 
Published: February 2015

Abstract
In this paper the results of X-ray diffraction experiments of Ln-Si-Al-O-N (Ln = La, Gd, Yb) glasses are presented. Total structure factors and pair correlation functions allow the determination of the first coordination sphere of Ln atoms. The bond lengths observed correspond to the ionic radii of the Ln-ions surrounded by oxygen and nitrogen atoms. The presence of non-bridging nitrogen is discussed together with results of neutron diffraction, NMR-experiments and XPS-studies of other authors.
A New Type of Chaotic Attractor
Authors: Kleiner Normann , Fischer Sebastian , Fröhlich Dieter 
Published: February 2015

Abstract
An experimentally discovered inverted spiral-type chaotic attractor is reproduced by a model equation. Does there exist a simple equation for the attractor re-cently found both in an electronic and a hydrodynamical system [1]? After a first, unpublished attempt by Sven Sahle to mirror a classical spiral-type attractor using a tube put into the middle, which yielded "messy" equa-tions, a fairly simple ordinary differential equation (ODE) was found and will be presented in the following. An experimental result is reproduced in Figure 1. It Deviation Fig. 1. Experimental attractor obtained with a hydrodynami-cal system, cf. [1]
Direct Estimation of the Chemical Potential of Molten NaCl by Molecular Dynamics Simulation
Authors: Takagi Ryuzo , Sakurai Masanori 
Published: February 2015

Abstract
Molecular dynamics simulation of molten NaCl was carried out at 1200 K with well defined potential parameters. The chemical potential of the melt was satisfactorily estimated with the method pro-posed by Powles et al., which requires only positional data of the ions at the temperature in question, when the number of ions in the basic cell is large enough.
Electrohydrodynamic Kelvin-Helmholtz Instability of Two Rotating Dielectric Fluids
Authors: El-Sayed Mohamed Fahmy 
Published: February 2015

Abstract
A linear stability analysis of a novel electrohydrodynamic Kelvin-Helmholtz system consisting of the superposition of two uniformly rotating dielectric media is presented. The characteristic equation for such an arrangement is derived, which in turn yields a stability criterion for velocity differences of disturbances at a given rotation frequency. The conditions of stability for long and short wave perturbations are obtained, and their dependence on rotation, surface tension and applied electric field is discussed. Limiting cases for vanishing fluid velocities, rotation frequency, and applied electric field are also discussed. Under suitable limits, results of previous works are recovered. A detailed analysis for tangential and normal applied electric fields, in the presence and absence of surface charges, is carried out.
New Aspects in the Calculation of Electronic Momentum Properties; an All-Quantum Study
Authors: Böhm Michael C. , Ramírez Rafael , Schulte Joachim 
Published: February 2015

Abstract
The electronic properties of the C6H6 and C6D6 molecules have been studied by an all-quantum approach, where the classical and quantum degrees of freedom of the nuclei are taken into ac-count in the evaluation of electronic expectation values. In the all-quantum approach suggested a Feynman path integral Monte Carlo (PIMC) formalism has been linked to an electronic ab initio Hamiltonian. The electronic expectation values have been calculated as averages over the manifold of nuclear configurations populated in thermal equilibrium. This theoretical setup leads to electronic expectation values that depend on the temperature and on the mass of the nuclei. The ensemble averaged electronic properties differ sizeably from the results derived on the basis of a single nuclear configuration of minimum energy. This behaviour should have physical implications for the theoretical calculation of electronic momentum properties such as Compton profiles, reciprocal form factors, etc. We describe an error source in the theoretical determination of electronic momentum properties which has not been commented so far.
A Deterministic Entropy Based on the Instantaneous Phase Space Volume
Authors: Diebner Hans H. , Rössler Otto E. 
Published: February 2015

Abstract
A deterministic entropic measure is derived for the time evolution of Newtonian N-particle systems based on the volume of the instantaneously occupied phase space (IOPS). This measure is found as a natural extension of Boltzmann's entropy. The instantaneous arrangement of the particles is exploited in the form of spatial correlations. The new entropy is a bridge between the time-dependent Boltzmann entropy, formulated on the basis of densities in the one-particle phase space, and the static Gibbs entropy which uses densities in the full phase space. We apply the new concept in a molecular dynamics simulation (MDS) using an exactly time reversible “discrete Newtonian equation of motion” recently derived from the fundamental principle of least action in discretized space-time. The simulation therefore is consistent with micro-time-reversibility. Entropy becomes an exact momentary observable in both time directions in fulfillment of a dream of Boltzmann.
The Structure of N-Acetylprolinamide in the Solid State and in the Gasphase. A Remarkable Lattice Effect as the Result of a Competition Between Inter-and Intramolecular Hydrogen Bonds of Different Strengths
Authors: Raabe Gerhard , Sudeikat Axel , Woody Robert W. 
Published: February 2015

Abstract
In the solid state, the conformation of N-actetylprolinamide is stabilized by two intermolecular O···H bridges and one intramolecular N···H hydrogen bond. According to quantum chemical ab initio calculations with the 6-31+G* basis set at the one-determinant level, the intramolecular N ···H bond is not strong enough to maintain the solid-state molecular conformation the gas phase. The conformational changes predominantly consist in a rotation of the amide group about its C-C bond to the proline ring, resulting in a c/s-like conformation which is stabilized by a presumably stronger intramolecular O···H bond between one hydrogen atom of the NH2 group and the carbonyl oxygen of the acetyl subsituent bonded to the nitrogen atom of the five-membered ring.
These confirmational changes cause a reduction of the molecular dipole moment by about 50%, indicating that the conformation in solution might be strongly solvent dependent.
While both the MINDO/3 and the MNDO method in their standard parametrizations fail to reproduce the ab initio results, the lattice effect is reproduced at least qualitatively with the PM3 as well as with the AM1 method.
Interaction of Alkaline Earth Metal Ions with Carboxylic Acids in Aqueous Solutions studied by 13C NMR Spectroscopy
Authors: Kondoh Akiko , Oi Takao 
Published: February 2015

Abstract

13C NMR spectroscopic measurements of aqueous solutions containing alkaline earth metal chloride and a carboxylic acid have been carried out to acquire some insight into the coordination manners of various carboxylic acids to alkaline earth metal ions. The dependence of the 13C NMR signal positions of the carboxylate carbons on the magnesium ion concentration in a magnesium carboxylate system is a good index to understand the coordination manner of the carboxylate ion. The upfield shift of the carboxylate carbon signal with increasing magnesium ion concentration indicates that the carboxylate ion acts as a bidentate ligand to form a ring structure. Only in the citrate systems, the existence of a relatively stable complex is evidenced in which the citrate ion is expected to act as a tridentate ligand.
Transmission of Binary Information with a Chaos Coded Communication System using QDPSK-Modulation
Authors: Magauer Andreas , Banerjee Soumitro 
Published: February 2015

Abstract
Synchronisation of chaotic oscillators offers a way of practical application of the theory of Chaos in obtaining secure communication. In this work we introduce a nonautonomous chaotic system with sinusoidal external force for communication of binary signals. The information is applied to the phase position of the sinusoidal forcing signal of the chaotic oscillator using a quadrature difference phase shift keying (QDPSK) modulation. An inverse synchronisation system approach with direct modulation is applied. We describe the system in detail and discuss the requirements of a secure communication system. Issues related to bit error rate, transfer rate, signal to noise ratio, channel bandwidth, bandwidth efficiency and channel capacity are discussed, and the properties of the realized communication system are placed in relation to the requirements of a secure communication system.
Dielectric Study of the Ferroelectric Phase Transition in DMAGaS Crystal
Authors: Tchukvinskyi R. , Cach R. , Czapla Z. 
Published: February 2015

Abstract
Electric permittivity measurments as functions of temperature at constant dc electric field and as functions of the dc electric field at constant temperatures in the paraelectric phase have been performed for DMAGaS crystal. The changes of the permittivity maximum with the electric field intensity evidence the first-order character of the ferroelectric phase transition at Tc1. The field dependence of the permittivity ε(E) in the paraelectric phase is discussed, using the classical electric equation of state. A method for the determination of the corresponding coefficients is proposed. The obtained B and C coefficients, together with double hysteresis loop observed above Tc1 prove the first-order character of the ferroelectric phase transition in DMAGaS crystal.
A New Tool for Nonlinear Dynamical Analysis of Heart Rate Variability
Authors: Posiewnik A. , Da̢bkowski J. 
Published: February 2015

Abstract
In this paper we analyse the sequences of the time intervals between heart-beats-the RR intervals-by means of AIP (artificial insymmetration patterns) diagrams.
The sequences were produced by artificial heartbeat sequences generated numerically and compared with sequences obtained from real heart activity.
We hope that the AIP diagrams method will prove useful for a rapid qualitative assessment of dynamics from nonlinear time series, and that it is able to distinguish various types of heart dynamics (regular and pathological), while other diagnostical methods fail.
Dielectric Studies of a Substance with Negative Dielectric Anisotropy
Authors: Urban S. , Gestblom B. , Dąbrowski R. , Kresse H. 
Published: February 2015

Abstract
The results of dielectric studies of 6BAP(F) (1-[4-(hexylbicyclo[2,2,2]octyl]-2-(3-fluoro-4-methoxy-phenyl)ethane) in the nematic and isotropic phases are presented. The substance has a negative dielectric anisotropy. By applying two experimental techniques, using a network analyzer and time domain spectrometer (TDS), the two main relaxation processes, connected with the molecular reorientation around the short and long axes, respectively, were resolved in the phases studied. The activation barriers hindering the motions were obtained. By extrapolation of the longitudinal and transverse relaxation times from the isotropic to the nematic phase the retardation factors, g∥ and g⊥, and the nematic potential versus temperature could be calculated. These are discussed together with the order parameter S obtained from the refractive index, and are compared with the predictions of the mean-field theories.
Nematic Potential and Order Parameter Determined from Dielectric Measurements
Authors: Würflinger A. 
Published: February 2015

Abstract
The Maier-Saupe theory is employed in order to calculate order parameters S from the nematic potential q. It is found that one of the basic assumptions of the Maier-Saupe theory, q~S, is approximately fulfilled. The relation between q and S is analysed for various state changes. Previously reported findings for 7 PCH that q~S, not fulfilled along isochoric changes, can be explained by taking into account the pressure and temperature dependences of q. The procedure described in this paper allows to treat experimental data for the nematic potential in a unique way, without being affected by inadequacies of experimentally determined order parameters.
Dielectric Spectroscopy of Some Multihydroxy Compound Solutions in Water/Tetrahydrofuran Mixtures
Authors: Hanna F. F. , Saad A. L. G. , Shafik A. H. , Biedenkap R. , Stockhausen M. 
Published: February 2015

Abstract
The dielectric spectra up to 72 GHz have been measured at 20 °C for solutions of glucose and sorbitol (max. 1 mol/1) in the mixed solvent water/tetrahydrofuran (THF) as a function of the THF content (max. volume fraction 0.4). There is no significant difference in the relaxation behaviour of corresponding glucose and sorbitol systems. The spectra of binary water/THF as well as hydroxy compound/water systems show that the respective minor components influence the structure and dynamics of water. The ternary systems hydroxy compound/water/THF, however, exhibit merely a superposition of those effects, thus there is no evidence for an interaction between the hydroxy compound and THF in aqueous environment.
Measurement and Calculation of Electric Field Gradients in Hg-Mercaptides
Authors: Soldner Torsten , Tröger Wolfgang , Butz Tilman , Blaha Peter , Schwarz Karlheinz , Isolde  
Published: February 2015

Abstract
Electric field gradients (EFG) at Hg were determined in mercury mercaptides Hg(S(CH2)i CH3)2 experimentally for i ∈ {0, 1, 2} using time differential perturbed angular correlation and theoreti-cally for i ∈ {0, 1} with the full potential linearized augmented plane wave code WIEN95. Due to the large unit cells and small hydrogen atoms not full convergence of the plane wave basis set could be reached. Nevertheless, the calculated EFGs agree with experimental values to better than 20%. Furthermore, isolated molecules for i ∈ {0, 1) were investigated theoretically, and strong differences to the values for the crystalline state, especially for the asymmetry parameters η, were found.