bluuebunny/crossref_metadata_2025 huggingface dataset:
Micro Relativity
Authors: Rössler Otto E. , Diebner Hans H. , Pabst Werner
Published: February 2015

A new synthesis based on microscopic classical thinking is attempted in the spirit of the molecular-dynamics-simulation (MDS) paradigm. Leibniz’s idea that joint scale transformations cancel out is invoked. Boltzmann discovered that a time reversal in the whole universe is undetectable from the inside. As a corollary, objective micro time reversals occur in the interface between a subsystem and the rest of the universe, whenever the former undergoes a time reversal. This is shown to occur in a generic class of Hamiltonian systems. The “microinterface” arrived at generalizes the macro frame of relativity to the micro realm. Micro relativity comprises Bohr’s idea of an observer-relative complementarity and Everett’s idea of an observer-relative state. As in relativity proper, a multiplicity of worlds (cuts) exist. For the inhabitants of an artificial MDS universe, therefore a radically new option is available: world change technology.
Computer Simulation of the Order-Disorder Transition in Ammonium Chloride
Authors: Goc Roman , Wąsicki Jan W.
Published: February 2015

The phase transition at Tc = 243 K in ammonium chloride is well established to be of the order-disorder type. The ammonium chloride has a CsCl-type cubic structure with hydrogen atoms pointing toward four of the eight chloride ions at the corners of the unit cell. This means that there are two possible orientations of ammonium tetrahedron; a and b. In the ordered phase below the Tc temperature all ammonium ions have the same, let it be a, orientation. Above the Tc temperature ions are randomly distributed among the two possible orientations a and b. An attempt was made to correlate such structural transition with the second moment of the proton NMR absorption line. This approach was chosen because the second moment is the parameter of the NMR line for which the exact theoretical formula exist, and which is mainly a function of the structure and the reorien-tational state of the studied material. It was found that the NMR second moments calculated for the described above model of the structural transition properly reflect the changes of the experimental NMR second moments measured at temperatures below and above this transition.
35Cl NQR Studies of Bismuth Trichloride
Authors: Babu P. K. , Ramakrishna J.
Published: February 2015

The temperature dependence of the 35Cl nuclear quadrupole resonance (NQR) frequency and spin lattice relaxation time (T1) are studied in crystalline BiCl3 , in the range 40-300 K. The positive temperature coefficient observed for one of the 35Cl resonances is explained in terms of the strong intermolecular interactions that exist in this compound. Variation of with temperature is found to be similar at the chemically inequivalent halogen sites. Semiclassical descriptions based on torsional oscillator dynamics are found to be inadequate for explaining the spin lattice relaxation. T1 (T) data follow an AT2 + BT3 type behaviour, indicating that the anharmonic nature of the lattice vibrations plays a significant role in determining the temperature dependence of T1 at high temperatures.
Charge Transport and Relaxation in Triglycine Sulphate (TGS)
Authors: Osak W.
Published: February 2015

Charging currents, J-V characteristics and electron conductivity have been measured in triglycine sulphate along three crystallographic directions: a, b and c. The measurements have been taken in a wide temperature range between −196°C and 80 °C. It is found that the charging currents have short relaxation times in the directions: a and c and a long relaxation time along the ferroelec-tric b axis. The J-V characteristics in the direction of the a and c axes have the shapes characteristic for linear dielectrics with space charge limited currents. The J-V characteristic for the b axis depends on the temperature: In the region of the phase transition the Fridkin-Kreher formula (J ∝ V4/3) is satisfied; for low temperatures characteristic agrees with SCLC theory for linear dielectrics with Gaussian traps energy distribution. The d.c. conductivity along the c axis is much higher than along the a and b axes. In the investigated temperature range, the electrical conductivity has an activation character. For −100 °C < T < −193 °C there is: σ ∝ (1/T) exp (− E/kT) . The activation energy depends both on the crystallographic direction and on the temperature-range. For low temperatures, T < −100 °C, the activation energies are very small (of the order of a few hundreds eV).
An Exact and Simple Approach to log-log Plots for Defect and Ionic Equilibria
Authors: Spinolo Giorgio , Anselmi-Tamburini Umberto , Ghigna Paolo
Published: February 2015

An alternative approach to log-log plots for defect equilibria in the solid state and ionic equilibria in solution is presented. The method is based on the strictly monotone character of the functional dependence of an externally controlled thermodynamic variable (e.g. the oxygen partial pressure P(O2) for the defect equilibria in a simple oxide, or a total concentration for the ionic equilibria in solution) on a chemically relevant compositional variable (such as the electron concentration n for defect equilibria, or [H3O+] or a free ligand concentration for solution equilibria). This functional dependency can be safely inverted. The concentration of all species and the externally controlled thermodynamic variable can be calculated as a function of the chemically relevant compositional variable. The appropriate plots are then obtained using naively a spreadsheet program. This method gives exact results in many more cases than the traditional approach.
Cationic Self-diffusion in Solid Choline Perchlorate Studied by NMR
Authors: Ishida Hiroyuki , Kato Masakazu , Ono Hiroshi , Ikeda Ryuichi
Published: February 2015

The 1H spin-lattice and spin-spin relaxation times, and the second moment of the 1H NMR linewidth of choline Perchlorate, [(CH3)3NCH2CH2OH]ClO4, were measured in its highest-temperature solid phase, i. e. above 275 K. X-ray powder patterns taken at ca. 380 K revealed that in this phase the crystal has a CsCl-type cubic structure (a = 6.326(4) Å and Z = 1). From 1H NMR experiments it was found that the cations in this phase undergo isotropic rotation and translational self-diffusion. From the 1H T1, measurements, the activation energies of the cationic rotation and self-diffusion were evaluated to be 21.4 ± 0.4 and 62 ± 3 kJ mol-1 , respectively.
The Kinetics of Catalytic Reactions Studied by Resistivity Measurements on Thin Metal Films
Authors: Finzel H.-U. , Heping Bi , Wissmann P.
Published: February 2015

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

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

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

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

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.
Thermodynamic Formalism and Phase Transitions of Generalized Mean-Field Quantum Lattice Models
Authors: Gerisch T. , Rieckers A. , Volkert H.-J.
Published: February 2015

The general structure of thermodynamic equilibrium states for a class of quantum mechanical (multi-lattice) systems is elaborated, combining quantum statistical and thermodynamical methods. The quantum statistical formulation is performed in terms of recent operator algebraic concepts emphasizing the role of the permutation symmetry due to homogeneous coarse graining and employing the internal symmetries. The variational principle of the free energy functional is derived, which determines together with the symmetries the general form of the limiting Gibbs states in terms of their central decomposition. The limiting minimal free energy density and its possible equilibrium states are analyzed on various levels of the description by means of convex analysis, where the Fenchel transforms of the free energies provide entropy like potentials. On the thermodynamic level a modified entropy surface is obtained, which specifies only in combination with its concave envelope the regions of pure and mixed phase states. The symmetry properties of a certain model allow to specify the (non-) differentiability of the minimal free energy density. A characterization and classification of phase transitions in terms of quantum statistical equilibrium states is proposed, and the connection to the Landau theory is established demonstrating that the latter implies a (continuous) deformation of the sets of equilibrium states along a canonically given curve.
Three-body Effects in Calcium(II)-ammonia Solutions: Molecular Dynamics Simulations
Authors: Sidhisoradej Wiwat , Hannongbua Supot , Ruffolo David
Published: February 2015

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

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

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

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

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

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

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

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]
A Theoretical Approach to Control Chebyshev Polynomials Chaos
Authors: Posiewnik Andrzej
Published: February 2015

We theoretically investigate the Güémez-Matias method for controlling chaotic behaviour. We obtain an algorithm to determine the value of the control parameter γ.

Numerical simulations confirme our theoretical approach.
Direct Estimation of the Chemical Potential of Molten NaCl by Molecular Dynamics Simulation
Authors: Takagi Ryuzo , Sakurai Masanori
Published: February 2015

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

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

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

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

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

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

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

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

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

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

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

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

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.
121,123Sb and 209Bi Nuclear Quadrupole Resonance Study of Complex Compounds of Antimony(III) and Bismuth(III) in the Temperature Range 77-400 K
Authors: Zemnukhova L. A. , Davidovich R. L.
Published: February 2015

A large number of solid fluoride and heteroligand acidocomplex compounds of antimony(III) and bismuth(III) with single and mixed cations has been prepared from aqueous solutions. Their crystal structures and 121,123Sb and 209Bi NQR spectra have been investigated in a wide temperature range.
35Cl NQR, 1H NMR, and X-Ray Diffraction Studies in a Hydrogen Bonded Complex Na2PtCl6 · 6H2O
Authors: Miyoshi Hiroshi , Horiuchi Keizo , Sakagami Narumi , Okamoto Kenichi , Ikeda Ryuichi
Published: February 2015

The 35Cl NQR frequencies, spin-lattice relaxation time and 1H NMR relaxation time were measured on crystalline Na2PtCl6 • 6H2O at 77-350 K. The presence of three nonequivalent chlorine sites found by X-ray diffraction measurement is in agreement with the observed three NQR lines, which have different temperature dependences attributable to differences in the direction of H-bonding with water molecules. The three NQR lines correspond to three kinds of chlorines with different Pt-Cl distances and H-bond directions.
Quantentheorie und die Teilung der Welt
Authors: Haag Rudolf
Published: February 2015

We discuss an ontological model suggested by quantum physics. In presently existing theory its scope is limited. The judgment of the significance of these limitations depends on further developments.
Remarks on Some Basic Issues in Quantum Mechanics
Authors: Englert Berthold-Georg
Published: February 2015

Two-way interferometers with which-way detectors are not only of importance in physical research, they are also a useful teaching device. A number of basic issues can be illustrated and discussed, even at the level of undergraduate teaching. Among these issues are: the physical meaning of a state vector; entangled systems; Einstein-Podolsky-Rosen correlations; statistical operators and the as-if realities associated with them; quantum erasure; Schrödinger's cat; and, finally, wave-particle duality.
Phase Structures in the Micromaser Photon Statistics
Authors: Bergou János A. , Bogár Pál
Published: February 2015

In the photon number distribution p(θ,k) of the micromaser, distinct structures are formed by the ridges connecting the peaks in the θ-k space. We refer to these structures as phases. By a simple condition we can distinguish between "semiclassical" and "quantum" regimes of operation near and far above threshold, respectively. In the semiclassical regime, the equations of state of the phases θ= θ(k) are monotonous and coincide with the steady state solutions of the semiclassical theory. They reflect typical features of the micromaser dynamics. The transition jumps, e. g., between the phases decrease with increasing pumping parameter θ, signifying the onset of the Jaynes-Cummings collapse. On increasing 9 further, the phases first disintegrate and then restructure into new kinds of phases in the quantum regime. The equations of state are no longer monotonous. Large single peaks, the quantum island states (QIS), develop in the neighborhoods of minima. The system undergoes oscillations between two kinds of quantum island states, QIS- and QIS+ , as a function of θ. The disintegration and transformation of phases recur periodically as θ is varied, and the phases in the semiclassical region are followed by consecutive phase structures in the quantum regime. The subsequent collapses and revivals of phases are directly connected to the Jaynes-Cummings collapse and revival. The observation of these phase structures and the accompanying QIS is experimentally feasible.
Maxwell Construction and Phase Transitions in Fermi Fluids
Authors: Pearson J. M. , Stocker W.
Published: February 2015

We apply elementary thermodynamics to Fermi fluids with a view to establishing the conditions for liquid-gas phase transitions at absolute zero. Particular attention is paid to the case of single-component nuclear matter (both charge-symmetric and pure neutronic cases).
Dynamical Description of Coulomb Dissociation
Authors: Typel S. , Wolter H. H.
Published: February 2015

We present a simple and efficient method for a fully dynamical treatment of Coulomb excitation in the semiclassical approximation by solving the time-dependent Schrödinger equation. It allows to investigate the importance of higher order effects in the breakup process. The method is applied to the Coulomb breakup of 7Li scattered on 197 Au at 42 MeV projectile energy.
Compatibility of Neutron Star Masses and Hyperon Coupling Constants
Authors: Huber H. , Weigel M. K. , Weber F.
Published: February 2015

It is shown that the modern equations of state for neutron star matter based on microscopic calculations of symmetric and asymmetric nuclear matter are compatible with the lower bound on the maximum neutron-star mass for a certain range of hyperon coupling constants, which are constrained by the binding energies of hyperons in symmetric nuclear matter. The hyperons are included by means of the relativistic Hartree-or Hartree-Fock approximation. The obtained couplings are also in satisfactory agreement with hypernuclei data in the relativistic Hartree scheme. Within the relativistic Hartree-Fock approximation, hypernuclei have not been investigated so far.
Structure and Dynamic Properties of Molten Lanthanum Tribromide
Authors: Okamoto Yoshihiro , Ogawa Toru
Published: February 2015

The structure of molten LaBr3 was investigated by X-ray diffraction and molecular dynamics simu-lations. It was found that the short range structure of molten LaBr3 is very similar to that of molten LaCl 3 , except for some structural features such as interionic distances based on the difference of anion sizes. In the MD simulation, the shear viscosity of molten LaBr3 was estimated from the structurally-optimized MD calculations.
Resistivity and Carrier Mobility of the SmBa2 Cu3 O6+x Superconductor with Different Oxygen Doping Levels
Authors: Spinolo G. , Ghigna P. , Chiodelli G. , Ferretti M. , Flor G.
Published: February 2015

DC conductivity measurements between 15 and 300 K are reported for SmBa2 Cu3O6+x samples with different oxygen doping amounts (x) produced by annealing under appropriate high temperature and oxygen pressure conditions and quenching. Samples with x≥0.5 are superconductors: Tc ~60 K at x=0.7, Tc >80 K at ; x=0.9. The transition from superconduction to non-superconduction corresponds to the tetragonal to orthorhombic structural tran-sition and to the transition from semiconducting to metallic temperature dependence of the resistivity. Oxygen doping causes a sudden increase of hole mobility near x=0.5. Below this threshold, the be-havior of the carrier mobility is in agreement with an Anderson localization.
A Generalized Debye Scattering Formula and the Hankel Transform
Authors: Wieder Thomas
Published: February 2015

The diffracted intensity of an x-ray or neutron diffraction experiment is expressed as an integral over an atomic position distribution function. A generalized Debye scattering formula results. Since this distribution function is expanded into a series of spherical harmonics, an inverse Hankel transform of the intensity allows the calculation of the expansion coefficients which describe the atomic arrangement completely. The connections between the generalized Debye scattering formula and the original Debye formula as well as the Laue scattering formula are derived.
Rotational Spectra of Phosphorus Monosulfide up to 1 THz
Authors: Klein H. , Klisch E. , Winnewisser G.
Published: February 2015

The submillimeter-wave rotational spectrum of the PS radical in the electronic and vibrational ground state (X2 ΠI/2 , X2Π3/2) was recorded with the Cologne terahertz spectrometer in the fre-quency region between 540 GHz and 1.07 THz, covering rotational quantum numbers from J = 30.5 to 60.5. The PS radical has been produced by discharging PSCl3 buffered with Ar. For all transitions the Λ-doubling was resolved for both the 2ΠI/2 and 2Π3/2 states. For some transitions with ΔF = 0 the hyperfine structure (hfs) caused by the P-atom could partially be resolved even for rather high J values. Analysis of the complete rotational data set of PS allows the derivation of a full set of molecular parameters, including the rotational constants B, D, H, the fine-structure constants A,γ , Dγ , the parameters for the Λ-doubling p, Dp , q, and the magnetic hyperfine constants a, b, c, d, CI. All parameters have been determined, whereby a, c, and the nuclear spin rotation-constant CI were obtained for the first time.
Parasites and Pattern Formation
Authors: Ackermann J. , Kirner T.
Published: February 2015

Biological information is coded in replicating molecules. To maintain a given amount of in-formation a cooperative interaction between these molecules is essential. The main problem for the stability of a system of prebiotic replicators are emerging parasites. Stabilization against such parasites is possible if space is introduced in the model. Complex patterns like spiral waves and self-replicating spot patterns have been shown to stabilize such systems. Stability of replicating systems, however, occurs only in parameter regions were such complex patterns occur. We show that parasites are able to push such systems into a parameter region were life is possible. To demonstrate this influence of parasites on such systems, we introduce a parasitic species in the Gray-Scott model. The growing concentration of parasites will kill the system, and the cooperative Gray-Scott system will be diluted out in a well mixed flow reactor. While considering space, in the model stabilizing pattern formation in a narrow parameter region is possible. We demonstrate that the concentration of the parasitic species is able to push the system into a region were stabilizing patterns emerge.
Influence of the rf Field Inhomogeneity on Nutation NQR Spectra of Spin 3/2 Nuclei in Powders
Authors: Sinyavsky N. , Maćkowiak M. , Velikite N.
Published: February 2015

The influence of the rf field inhomogeneity on the NQR nutation spectra of spin / = 3/2 nuclei in powder samples is investigated. To eliminate the rf field inhomogeneity effects, a method of reconstruction of the NQR nutation spectra, based on finding the deconvolution of the Fourier nutation spectrum with a function of the rf field distribution, is used. The method is successfully demonstrated for simulated and experimental NQR nutation spectra of 35C1 in TiCl4 . The lineshape analysis of reconstructed nutation spectra allowing the determination of the EFG asymmetry parameter is given. The real advantage of the proposed method is that the high-resolution nutation spectrum may be obtained for a sample filling up the entire coil.
PVT and DTA Measurements on trans-4-n-Hexyl- (4'-Cyanophenyl)-Cyclohexane (6PCH) up to 300 MPa
Authors: Sandmann M. , Hamann F. , Würflinger A.
Published: February 2015

The phase diagram of trans-4-n-hexyl-(4'-cyanophenyl)-cyclohexane, (6PCH) has been established by high-pressure differential thermal analysis. Specific volumes are presented for temperatures between 300 and 370 K up to 300 MPa. The p,Vm ,T data have been determined for the nematic, isotropic, and (partly, in the neighbourhood to the melting curve) solid phases. Volume and enthalpy changes along the phase transitions have also been calculated. As previously, the p,Vm,T data were used to calculate the volume entropy for the nematic-isotropic transition. The molar volumes along the clearing line TNI (p) enabled us to calculate the molecular field parameter γ = ∂ln TNI/∂In VNI , being 4.1.
Molecular Orientation in Uniaxial Liquid Crystal Phases as Studied by Electron Paramagnetic Resonance
Authors: Moryson Hanka , Bauman Danuta , Hilczer Wojciech , Hoffmann Stanislaw
Published: February 2015

The electron paramagnetic resonance spectra of 3/ß-doxyl-5α-cholestane dissolved in five liquid crystals have been recorded as a function of temperature in the isotropic and mesogenic phases. From these spectra the order parameter (P2) has been determined. The results have been com-pared with the data obtained from the optical birefringence measurements and from the polarized absorption spectra of the dichroic dye dissolved in liquid crystal host.
Magnetic Susceptibility Calculated from Correlation-Lengths Derived by Mössbauer Relaxation Spectra
Authors: Pebler J. , Frommen C. , Mangold M.
Published: February 2015

From the knowledge of the spin correlation functions derived from Mössbauer relaxation spectra of quasi-one-dimensional A2Mn0.98Fe()()2F5(H2O) we could fit the antiferromagnetic susceptibilities of A2MnF5(H2O) with A = Na+, (NH4)+, K+, Rb+ obtained for single crystal samples. The calculation yielded characteristic parameters such as the local anisotropy D, the intra-chain exchange energy J, the inter-chain exchange energy |Jʹ|, the Neel temperature TN, and the spin canting angle φ.
Stability of Two Superposed Viscoelastic (Walters B') Fluid-Particle Mixtures in Porous Medium
Authors: Kumar Pardeep
Published: February 2015

The stability of the plane interface separating two viscoelastic (Walters B') superposed fluids in por-ous medium in the presence of suspended particles is considered. For the case of two uniform Walters B' fluids separated by a horizontal boundary, the system is found to be stable or unstable under certain conditions for the stable configuration. However, the system is found to be unstable for the unstable configuration. The case of an exponentially varying density is also considered. For the stable stratifica-tion, the system is found to be stable or unstable under certain conditions, whereas the system is found to be unstable for the unstable stratification. The behaviour of growth rates with respect to suspended particle, number density, and medium permeability is examined analytically.
Large Nonlinear Optical Response in Carbon Nitride Nanotube
Authors: Xie Rui Hua
Published: February 2015

The third-order optical nonlinearity of a nitrogen doped car-bon nanotube is studied. It is found that carbon nitride nano-tubes are potentially important in photonics owing to their large nonlinear optical response.
Ionic Interactions in Alkali -Aluminium Tetrafluoride Clusters
Authors: Akdeniz Z. , Çiçek Z. , Karaman A. , Pastore G. , Tosi M. P.
Published: February 2015

Complex anion structures ((AlF4)-, (AlF5)2- and (AIF6)3-) coexist in liquid mixtures of alu-minium trifluoride and alkali fluorides in composition-dependent relative concentrations and are known to interact with the alkali counterions. We present a comparative study of the static and vibrational structures of MA1F4 molecules (with M = any alkali), with the aim of developing and testing a refined model of the ionic interactions for applications to the M-Al fluoride mixtures. We find that, whereas an edge-bridged coordination is strongly favoured for Li in LiAlF4 , edge-bridging and face-bridging of the alkali ion become energetically equivalent as one moves from Na to the heavier alkalis. This result is sensitive to the inclusion of alkali polarizability and may be interpreted as implying (for M = K, Rb or Cs) almost free relative rotations of the M+ and (AlF4)- partners at temperatures of relevance to experiment. The consistency of such a viewpoint with electron diffraction data on vapours and with Raman spectra on melts is discussed.
A Theoretical Study of the Stabilization of the (AlF5)2— Complex Anion by Alkali Counterions
Authors: Akdeniz Z. , Çiçek Z. , Karaman A. , Pastore G. , Tosi M. P.
Published: February 2015

We evaluate the relative stability of various states of coordination for the aluminium ion by fluorines in MnAlFn+3 microclusters, with M = Li, Na or K and n = 2 or 3. The calculations use ionic model interactions which have been adjusted and tested against experimental data and ab initio calculations on the (AlF4)- anion and on MAlF4 clusters. We confirm earlier results showing that the fivefold (AlF5)2- anion is stabilized by the counterions and assess the sensitivity of this result to the details of the model as well as the effect of alkali substitution. We evaluate the variation of the breathing mode frequency of the complex anions in these clusters for comparison with Raman scattering data from liquid mixtures ofAlF3 and MF in the basic range of composition.