bluuebunny/crossref_metadata_2025 huggingface dataset:
PCT-Invariance of Generalized de Broglie-Bargmann-Wigner Equations
Authors: Stumpf H.
Published: February 2015

Generalized de Broglie-Bargmann-Wigner (GBBW)-equations are part of the derivation of effective theories for composite particles based on a nonlinear spinor field model with canonical quantization, relativistic invariant selfregularization and probability interpretation. Owing to the close connection between the model itself and its GBBW-equations the behavior of both is studied under PCT-transformations leading to the proof of invariance against such tranformation of the field Hamiltonian as well as of the GBBW-equations. Finally the algebraic formulation of the operators of these transformations in general state spaces is derived as the nonperturbative algebraic treatment of the model is referred to such spaces which are inequivalent to the Fock space representation of perturbation theory.
A Simple Method for Computing Resistance Distance
Authors: Bapat Ravindra B. , Gutmana Ivan , Xiao Wenjun
Published: February 2015

The resistance distance ri j between two vertices vi and vj of a (connected, molecular) graph G is equal to the effective resistance between the respective two points of an electrical network, constructed so as to correspond to G, such that the resistance of any edge is unity. We show how rij can be computed from the Laplacian matrix L of the graph G: Let L(i) and L(i, j) be obtained from L by deleting its i-th row and column, and by deleting its i-th and j-th rows and columns, respectively. Then rij = detL(i, j)/detL(i).
EPR Study of Cu2+ and VO2+ Ions in [NH4H3(C2O4)2] ·2H2O Single Crystals
Authors: Biyik R. , Tapramaz R. , Karabulut B.
Published: February 2015

g

The EPR spectra of Cu2+ and VO2+ ions in [NH4H3(C2O4)2]·2H2O single crystals were recorded at room temperature in three orthogonal planes. The spectra indicate that the Cu2+ and VO2+ ions substitute NH+4 ions. The principal values of the and A tensors were determined. The ground state wave function of the Cu2+ ion in the lattice has been calculated and the covalancy and Fermi contact terms of the VO2+ ions were evaluated.
Nonlinear Partial Differential Equations Solved by Projective Riccati Equations Ansatz
Authors: Li Biao , Chen Yong
Published: February 2015

Based on the general projective Riccati equations method and symbolic computation, some new exact travelling wave solutions are obtained for a nonlinear reaction-diffusion equation, the highorder modified Boussinesq equation and the variant Boussinesq equation. The obtained solutions contain solitary waves, singular solitary waves, periodic and rational solutions. From our results, we can not only recover the known solitary wave solutions of these equations found by existing various tanh methods and other sophisticated methods, but also obtain some new and more general travelling wave solutions.
Anomalous Inhomogeneous Broadening of Electronic Spectra of Molecules with Internal Charge Transfer
Authors: Tomin V. I. , Hubisz K. , Mudryka Z.
Published: February 2015

Excited states with internal charge transfer of some molecules show an anomalously strong inhomogeneous broadening of their electronic spectra. Here such an inhomogeneous broadening for N, N-dimethylaminobenzonithrile (DMABN) was studied. The spectral inhomogeneity for DMABN in some polar solvents reaches 140 - 150 nm.

The interpretation of the obtained results is based on treating a solution as a set of chemically identical solvates with a luminophor molecule in the centre, having different energies of the pure electronic transitions. The inhomogeneity arises due to an intermolecular effect of the luminophors environment on its spectra in polar solvents, as well as a process of intramolecular movement of the twisting fragments relative to the main moiety of DMABN.
Critical Behavior of the Dielectric Modulus in Nitrobenzene-Dodecane Mixture
Authors: Malik P. , Rzoska S. J. , Drozd-Rzoska A. , Sułkowskia W. W. , Jadzynb J.
Published: February 2015

The dielectric properties of a homogenous critical mixture of nitrobenzene-decane were studied in the range 1 Hz< f1 Mz. The temperature dependences of the “static” dielectric permittivity ε’ (1 MHz) and the electric conductivity σ(1 Hz) exhibit pretransitional anomalies which may be associated with the same critical exponent ø = 1−α ≈ 0.88, where α is the critical exponent of the specific heat. The same data were analyzed using the dielectric modulus representation. They show loss curves for the imaginary part of the modulus M ̋( f ). It was found that the temperature evolutions of the peak frequency τ = 1/2π fp and the peak maximum of M ̋ =M ̋( fp) also exhibit critical anomalies. Their forms resemble anomalies obtained for the imaginary part of the dielectric permittivity ε̋( f ), carried out for 40 MHz < f <1 GHz, in an ethanol-dodecane critical mixture [S. J. Rzoska, K. Orzechowski, and A. Drozd-Rzoska, Phys. Rev. E 65, 042501 (2002)]. - PACS: 64.70.Ja, 77.20.+y , 64.60.Fr
Investigation of Eu3+ Site Occupancy in Cubic Y2O3 and Lu2O3 Nanocrystals
Authors: Concas Giorgio , Spano Giorgio , Bettinellia Marco , Speghinia Adolfo
Published: February 2015

The distribution of luminescent Eu3+ ions in crystals with the cubic bixbyite-type structure is subject of debate. In this work, the actual occupancy of the two cation sites available for europium in yttria and lutetia nanocrystals with sizes of 10 - 20 nm has been evaluated by means of 151Eu Mössbauer spectroscopy. The spectral contribution of the ion at different crystalline sites has been resolved, allowing for the quadrupole splitting. The spectra of the nanocrystalline Y1.8Eu0.2O3 and Lu1.8Eu0.2O3 compounds have been analyzed in detail; the C3i and C2 sites are occupied by the europium ion in a statistical way. The hyperfine parameters have been discussed in terms of symmetry and bonding. An increase of the covalence of the Eu-O bond has been found in the series of compounds Gd2O3, Eu2O3, Y2O3 and Lu2O3.
The Determination of Multiple Steady States in Two Families of Biological Systems
Authors: Chuang Guo-Syong , Ho Pang-Yen , Li Hsing-Ya
Published: February 2015

The capacity of computational multiple steady states in two biological systems are determined by the Deficiency One Algorithm and the Subnetwork Analysis. One is a bacterial glycolysis model involving the generation of ATP, and the other one is an active membrane transport model, which is performed by pump proteins coupled to a source of metabolic energy. Mass action kinetics, is assumed and both models consist of eight coupled non-linear equations. A set of rate constants and two corresponding steady states are computed. The phenomena of bistability and hysteresis are discussed. The bifurcation of multiple steady states is also displayed. A signature of multiplicity is derived, which can be applied to mechanism identifications if steady state concentrations for some species are measured. The capacity of steady state multiplicity is extended to their families of reaction networks.
Non-Linear Stability of an Electrified Plane Interface in Porous Media
Authors: El-Dib Yusry O. , Moatimid Galal M.
Published: February 2015

The non-linear electrohydrodynamic stability of capillary-gravity waves on the interface between two semi-infinite dielectric fluids is investigated. The system is stressed by a vertical electric field in the presence of surface charges. The work examines a few representative porous media configurations. The analysis includes Rayleigh-Taylor and Kelvin-Helmholtz instabilities. The boundary - value problem leads to a non-linear equation governing the surface evolution. Taylor theory is adopted to expand this equation, in the light of multiple scales, in order to obtain a non-linear Schr¨odinger equation describing the behavior of the perturbed interface. The latter equation, representing the amplitude of the quasi-monochromatic traveling wave, is used to describe the stability criteria. These criteria are discussed both analytically and numerically. In order to identifiy regions of stability and instability, the electric field intensity is plotted versus the wave number. Through a linear stability approach it is found that Darcy’s coefficients have a destabilizing influence, while in the non-linear scope these coefficients as well as the electric field intensity play a dual role on the stability.
Non-polynomial Third Order Equations which Pass the Painlevé Test
Authors: Muǧan Uǧurhan , Jrad Fahd
Published: February 2015

The singular point analysis of third-order ordinary differential equations in the non-polynomial class is presented. Some new third order ordinary differential equations which pass the Painlevé test, as well as the known ones are found.
Dielectric Studies of Smectogenic Members of the 4’-alkyl-4-cyanobiphenyl (nCB) Homologous Series
Authors: Czub Joanna , Gubernat Urszula , Gestblom Bo , Da̡browski Roman , Urban Stanisław
Published: February 2015

Results of dielectric studies of smectogenic members of the nCB (4’-alkyl-4-cyanobiphenyl, n = 9÷12) homologous series are presented. The dielectric relaxation measurements were performed in the isotropic (Is) and smectic A (SA) phases. The relaxation times characterizing the molecular rotations around the short axes (the low frequency, l. f., process) were established for both phases. In the Is phase the high frequency process connected with the molecular rotations around the long axes was also determined. The l. f. relaxation times were analysed using the Arrhenius and Bauer activation equations, which yielded the activation enthalpy ΔH and activation entropy ΔS. All results were analysed together with the literature data on the shorter members of the homologous series as well as on 14CB recently published. The ΔH and ΔS values show typical odd-even alternation that is especially well seen for the shorter members. In the Is phase the l. f. relaxation times are related to the viscosity data measured recently by Jadzyn et al.
Jacobi Elliptic Function Rational Expansion Method with Symbolic Computation to Construct New Doubly-periodic Solutions of Nonlinear Evolution Equations
Authors: Chen Yong , Wang Qi , Lic Biao
Published: February 2015

A new Jacobi elliptic function rational expansion method is presented by means of a new general ansatz and is very powerful, with aid of symbolic computation, to uniformly construct more new exact doubly-periodic solutions in terms of rational form Jacobi elliptic function of nonlinear evolution equations (NLEEs). We choose a (2+1)-dimensional dispersive long wave equation to illustrate the method. As a result, we obtain the solutions found by most existing Jacobi elliptic function expansion methods and find other new and more general solutions at the same time. When the modulus of the Jacobi elliptic functions m→1 or 0, the corresponding solitary wave solutions and trigonometric function (singly periodic) solutions are also found.
Phase Transitions by Dilatometry, Part I: Synthesis, Characterisation and Isotropic to Smectic-A and Smectic-A to Smectic-B Transitions in Two Liquid Crystalline Higher Homologues of N-(p-n-nonyloxybenzylidene) p-n-alkylanilines
Authors: Prabhu C. Rama Chandra , Lakshminarayana S. , Pisipatia V. G. K. M.
Published: February 2015

Two higher homologues of N(p-n-nonyloxybenzylidene)p-n-alkylanilines, viz. the 9O.m series with m = 12 and 16, are synthesised and characterised by thermal microscopy, differential scanning calorimetry and density studies. The compounds exhibit the phase variants smectic-A, smectic-B and smectic-G. Density studies reveal the first order nature of the isotropic to smectic-A and smectic-A to smectic-B transitions. An estimate of the pressure dependence of the phase transition temperature, using volume and enthalpy data, is presented. A comparison of these results with those reported on nO.m and other liquid crystalline compounds is presented.
Electronic Structure of Liquid Mercury Using Compton Scattering Technique
Authors: Ahuja B. L. , Sharma M. , Mathur S.
Published: February 2015

The isotropic Compton profile of mercury has been measured, using 661.65 keV gamma-rays from a 20 Ci 137Cs source. To extract the true experimental Compton line shape, besides the usual systematic corrections we have incorporated for the first time the background correction due to bremsstrahlung radiation generated by photo and Compton electrons. Theoretical computations have been carried out, using the renormalised-free-atom (RFA) for the electron configuration 4f145d106s2 and free electron models. It is found that the present experimental data with bremsstrahlung background correction are in better agreement with the RFA calculations. This work suggests the incorporation of the bremsstrahlung background correction in Compton scattering experiments of heavy materials using high-energy gamma-ray sources.
1H NMR Cryoporometry Study of the Melting Behavior of Water in White Cement
Authors: Boguszyńska Joanna , Tritt-Goc Jadwiga
Published: February 2015

The pore size of white cement samples is studied by the melting behaviour of water confined in it, using 1H NMR cryopormetry. The influence of the preparing method and antifreeze admixture on the pore size and distribution in cement samples is investigated at 283 K. The addition of an antifreeze admixture [containing 1% Sika Rapid 2 by weight of the dry cement] influences the porosity. In wet prepared samples we observed a significant increase in the quantity of mesopores between 0.8 and 5 nm and a smaller increase of mesopores between 5 and 10 nm, when compared to cement without admixture. The compressive strength is related to the porosity of the cement. Therefore the cement with Sika Rapid 2, wet prepared at 278 K shows a higher strength than all other measured samples.
Electronic Spectra and Stability of Cobalt Halide Complexes in Molten Calcium Nitrate Tetrahydrate
Authors: Zsigrai István J. , Gadzuric Slobodan B. , Nikolic Ruzica , Nagy László
Published: February 2015

The complex formation between cobalt(II) and chloride and bromide ions in molten calcium nitrate tetrahydrate at different temperatures has been studied by a spectrophotometric technique. Addition of halide ions to cobalt(II) nitrate solution in calcium nitrate tetrahydrate caused a pronounced shift of the absorption maximum toward lower energies and a large increase of absorption intensity, indicating a change from octahedral to a tetrahedral co-ordination. The change of co-ordination depends on temperature and halide concentration. Stability constants for the [Co(NO3)4]2−, [Co(NO3)2X2]2− and [CoX4]2− complexes at 40 and 70 ◦C and the corresponding species spectra are reported.
Study of the Comparative Solvation Behaviour of Na+ and Cu+ Cations in Acetonitrile + N,N-Dimethylformamide Mixtures at 298.15 K
Authors: Gill Dip Singh , Anand Hardeep , Puri J. K.
Published: February 2015

Viscosity and molar conductance of Bu4NBPh4, Bu4NClO4, [Cu(CH3CN)4]ClO4, NaClO4 and NaBPh4 have been measured in the concentration ranges 0.02 - 0.5 mol dm−3 and 0.0005 - 0.0065 mol dm−3 at 298.15 K in AN + DMF mixtures containing 0, 10, 20, 40, 60, 75, 80, 90, and 100 mol % DMF. The viscosity data have been analyzed by the extended form of the Jones-Dole equation in the form: (η/η0) = 1+AC1/2+BC+DC2 to evaluate B and D parameters and the conductance data by the Shedlovsky equation to evaluate Λo and KA values of the salts. Ionic viscosity B-coefficients (B±) and ionic molar conductances (λ◦ i) have been calculated by using Bu4NBPh4 as a reference electrolyte. Solvated radii (ri) for Na+, Cu+ and ClO4 − have been estimated by using Gill’s modification of Stokes’ law. The variation of B± and ri as a function of mol % DMF shows that both Na+ and Cu+ are highly solvated in AN + DMF mixtures over the entire composition region. The solvation passes through a maximum between 40 to 80 mol % DMF. Both Na+ and Cu+ are more strongly solvated between 40 to 80 mol % DMF. Cu+ is relatively more strongly solvated than Na+ in AN + DMF mixtures. ClO4 − shows poor solvation in AN + DMF mixtures.
Determination of the Force Constants of Non-linear XY2 Molecules in the Gas-Phase by the GF Matrix Method
Authors: Ucun Fatih , Gūçlü Vesile
Published: February 2015

The force constants of the internal coordinates of nonlinear XY2 molecules in the gas-phase were calculated by using the GF matrix method. The matrix solution was carried out by means a computer program built relative to the Newton-Raphson method and the calculations were listed in a table. The force constants of some molecules in the liquidand solid- phase were also found and compared with these ones, and it was seen that the force constants for more condensed phase are lower as in an agreement with having its lower frequency.
Ground-State Energy of a Weakly Interacting Bose Gas: Calculation Without Regularization
Authors: Weiss Christoph , Block Martin , Boers Dave , Eckardt André , Holthaus Martin
Published: February 2015

The textbook calculation of the ground-state energy of a dilute gas of Bose particles is examined in detail, and certain mathematical inconsistencies are pointed out. On the basis of this analysis, a refined approach suitable for soft interaction potentials which lend themselves to a low-order Born approximation is developed. This procedure emphasizes the low-density character of the resulting formula for the ground-state energy, and avoids all divergent expressions at intermediate stages of the computation. It is stressed that the standard Bogoliubov approximation, if not augmented by some additional device, leads to an error which manifests itself already in the lowest order of the density. - PACS 03.75.Hh, 05.30.Jp, 03.65.Nk.
Infrared, 1H and 13C NMR Spectral Studies on Di- and Tri-substituted N-Aryl Amides, 2,6-X2C6H3NHCOCH3 – IXi and 2,4,6-X3C6H2NHCOCH3 – IXi (X = Cl or CH3 and I = 0, 1, 2 or 3)
Authors: Gowda B. Thimme , Usha K. M. , Jyothi K.
Published: February 2015

Several di- and tri-substituted amides of the general formula, 2,6-X2C6H3NHCOCH3−iXi and 2,4,6-X3C6H2NHCOCH3−iXi (X = Cl or CH3 and i = 0, 1, 2, or 3) are prepared, characterised, and their infrared spectra in the solid state and 1H and 13C NMR spectra in solution are studied. The C=O stretching vibrations of N-(2,6-dichlorophenyl)- and N-(2,6-dimethylphenyl)-amides appear as strong absorptions in the ranges 1707 - 1658 cm−1 and 1700 - 1647 cm−1, respectively, while the N-H stretching vibrations of N-(2,6-dichlorophenyl)- and N-(2,6-dimethylphenyl)-amides appear as strong vibrations in the ranges 3271 - 3209 cm−1 and 3285 - 3214 cm−1, respectively. The N-H stretching vibrations of N-(2,4,6-trichlorophenyl)- and N-(2,4,6-trimethylphenyl)- amides also appear as strong absorptions in the ranges 3370 - 3212 and 3283 - 3225 cm−1, respectively, while those of the C=O vibrations appear in the ranges 1688 - 1617 and 1704 - 1647 cm−1. The analysis of the C=O and N-H absorption frequencies of all amides of the general formula XiC6H5−iNHCOCH3−iXi (where X = Cl or CH3, and i = 0, 1, 2 or 3) indicates that their variations do not show regular trends with substitution either in the phenyl ring or in the side chain. The chemical shifts of both the aromatic protons and the aromatic carbons of all the amides are calculated in two ways, either by adding the incremental shifts due to -COCH3−iXi groups and the substituents in the benzene ring to the chemical shifts of the corresponding aromatic protons or carbons of the parent aniline, or by adding the incremental shifts due to -NHCOCH3−iXi groups and the substituents in the benzene ring to the chemical shift of the benzene proton or carbon. The calculated chemical shifts of the aromatic protons and carbons of all the substituted amides by both methods lead to almost the same values in most cases and agree well with the observed chemical shifts, indicating that the principle of additivity of the substituent effects is valid in these compounds.
Phase Diagram of the TbBr3-KBr Binary System
Authors: Rycerz L. , Gaune-Escard M.
Published: February 2015

The phase equilibrium of the TbBr3-KBr has been established by Differential Scanning Calorimetry. This system has the three compounds K3TbBr6, K2TbBr5, and KTb2Br7 and two eutectics located at (χTb = 0.163 (885 K) and (χTb = 0.433 (697 K). K3TbBr6 undergoes a solid-solid phase transition at 691 K and melts congruently at 983 K with the corresponding enthalpies 8.0 and 48.0 kJ mol−1. K2TbBr5 melts incongruently at 725 K, and KTb2Br7 at 741 K. The latter forms at 694 K, a temperature very close to that (697 K) of one of the two eutectics also existing in the binary system.
Combinability of Travelling Wave Solutions to Nonlinear Evolution Equation
Authors: Liu Shikuo , Fu Zuntao , Liu Shida , Wang Zhanggui
Published: February 2015

First, applying the Jacobi elliptic sine function expansion, basic travelling wave solutions of some nonlinear evolution equations are obtained. Second, according to the formal invariance of nonlinear evolution equations, the sister travelling wave solutions, which have the same wave speed as the basic ones, are derived. Finally, we show that a suitable linear combination of these two solutions results in a combined travelling wave solution, whose wave speed is different from those of the basic and sister travelling wave solutions. The combination of travelling wave solutions to nonlinear evolution equations must satisfy certain conditions. - PACS: 03.65.Ge.
Variable Separation Approach for the Sine-Gordon System
Authors: Lai Xian-jing , Zhang Jie-fang
Published: February 2015

Using the B¨acklund transformation and a variable separation approach with some arbitrary functions, three new types of solutions of the sine-Gordon system have been obtained. The excitations are localized as well as non-localized. E.g. solitoffs, dromions, multidromions, lumps, breathers, instantons, multivalued solitary waves, doubly periodic waves, etc., can be constructed on the basis of selecting the arbitrary functions properly. Also the interaction properties for all the possible localized excitations are of interest. In this paper, we discuss two elastic interactions. - PACS Ref: 05.45.Yv, 02.30.Jr, 02.30.Ik.
Evidence for the Nonintegrability of a Water Wave Equation in 2+1 Dimensions
Authors: Gordoa P. R. , Pickering A. , Senthilvelan M.
Published: February 2015

We provide evidence of the nonintegrability of a recently proposed model for water waves in 2+1 dimensions: we show that under a nonlinear time transformation, a certain reduction of this partial differential equation is mapped to an ordinary differential equation which does not have the Painlev´e property. This is in contrast to what happens in the case of the Camassa-Holm equation. Also, and again in contrast to the case of the Camassa-Holm equation, the equation under study fails to admit Dirichlet series solutions. - MSC2000 classification scheme numbers: 35Q51, 35Q58, 37K10.
EPR of Gamma Irradiated Nα -Monochloroacetyl-α-Aminoisobutyric Acid
Authors: Başkan M. Halim , Osmanoğlu Şemsettin
Published: February 2015

Electron paramagnetic resonance of γ -irradiated single crystals of Nα -monochloroacetyl-α-aminoisobutyric acid were investigated at room temperature and 130 K. The paramagnetic center as attributed to the (CH3)2 ˙CCOOH radical.
Epr Spectra of VO2+ Doped in Na2C4H4O6 Single Crystals
Authors: Karabulut B. , Tapramaz R. , Köksal F.
Published: February 2015

EPR spectra of VO2+ ions in di-sodium tartrate, [Na2C4H4O6], single crystal and powder spectra have been studied at room temperature. The angular variation of the EPR spectra has shown that three different VO2+ complexes are located in different chemical environments, and each environment contains two magnetically inequvalent sites. The spin Hamiltonian parameters are determined, and these parameters have been used to assess the bonding coefficients of the VO2+ ion in the di-sodium tartrate lattice. The parallel and perpendicular components of axially symmetric g and hyperfine tensors are evaluated. The results are discussed.
Studies of the Spin Hamiltonian Parameters for Cubic V2+, Cr3+, and Mn4+ Centers In MgO and CaO, Based on Two Mechanism Models
Authors: Wu Shao-Yi , Dong Hui-Ning
Published: February 2015

The high-order perturbation formulas of the spin Hamiltonian (SH) parameters g-shift Δg (=g−gs) and the hyperfine structure constant A for a 3d3 ion in cubic octahedra are established, based on the two mechanism model. In this model, not only the contributions from the conventional crystal-field (CF) mechanism, but also those from the charge-transfer (CT) mechanism are taken into account. These formulas are applied to the investigation of the SH parameters of cubic V2+, Cr3+ and Mn4+ centers in MgO and CaO. Based on these studies, the sign of Δg due to the CT mechanism is opposite to that due to the CF mechanism, while the signs of the A factor due to the CF and CT mechanisms are equal. The theoretical results, including the contributions from the CF and CT mechanisms, agree better with the observed values than those containing only the conventional CF mechanism.
Electrochemical Studies on Lanthanum Ions in Molten LiCl-KCl-eutectic Mixture
Authors: Matsumiya Masahiko , Matsumoto Shin-ichiro
Published: February 2015

We have investigated the electrochemical behaviour of lanthanum ions in a eutectic molten mixture of LiCl and KCl, using linear sweep voltammetry, as well as semi-integration and semi-differentiation of cyclic voltammograms. It was found that the reduction of La3+ is quasi-reversible, and that the obtained diffusion coefficient of La3+ is consistent with that estimated from thermodynamic data. The electrochemical reduction, diffusion of La3+ in LiCl-KCl, and the structure and stability of the complex ion are discussed.
Interactions among Peakons, Dromions, and Compactons in (2+1)-Dimensional System
Authors: Bai Cheng-lin , Hu Hai-quan , Wang Wen-jun , Zhao Hong
Published: February 2015

Starting from a quite universal formula, which is valid for some quite universal (2+1)-dimensional physical models, the interactions among different types of solitary waves like peakons, dromions, and compactons are investigated both analytically and graphically. Some novel and interesting features are revealed. The results show that the interactions for peakon-dromion, compacton-dromion, and peakon-compacton may be completely inelastic, not-completely elastic or completely elastic. - PACS numbers: 05.45.Yv, 02.30.Jr.
Schottky Barrier Height Dependence on the Metal Work Function for p-type Si Schottky Diodes
Authors: Çankaya Güven , Uçar Nazım
Published: February 2015

We investigated Schottky barrier diodes of 9 metals (Mn, Cd, Al, Bi, Pb, Sn, Sb, Fe, and Ni) having different metal work functions to p-type Si using current-voltage characteristics. Most Schottky contacts show good characteristics with an ideality factor range from 1.057 to 1.831. Based on our measurements for p-type Si, the barrier heights and metal work functions show a linear relationship of current-voltage characteristics at room temperature with a slope (S=ϕb/ϕm) of 0.162, even though the Fermi level is partially pinned. From this linear dependency, the density of interface states was determined to be about 4.5 · 1013 1/eV per cm2, and the average pinning position of the Fermi level as 0.661 eV below the conduction band
Influence of DPPC Liposome Concentration on the Fluorescence Properties of PRODAN and LAURDAN
Authors: Kozyra K. A. , Heldt J. R. , Gondek G. , Kwiek P. , Heldt J.
Published: February 2015

Fluorescence spectral features of PRODAN and LAURDAN in phospholipid vesicles of different phase states were investigated. The results indicate that in the liquid crystalline phase the dominant emission results from the charge transfer (CT) excited state, whereas in the gel state of the membrane the emission from the locally excited (LE) state dominates. The fluorescence time studies point out that there are two radiation modes, one starting from only vibrationally relaxed excited states S1(LE)ν ((S1(CT)ν) and the other from a totally thermally equilibrated state S1(LE)EQ (S1(CT)EQ). In accordance with the obtained decay time dependencies, the fluorescence emission from total nonequilibrated excited states consists of a dominant or minor radiation process in the LE or CT band emission
Heat Capacity and Thermodynamic Properties of LaBr3 at 300 – 1100 K
Authors: Rycerz L. , Ingier-Stocka E. , Ziolek B. , Gadzuric S. , Gaune-Escard M.
Published: February 2015

The heat capacity of solid and liquid LaBr3 was measured by Differential Scanning Calorimetry (DSC) in the temperature range 300 - 1100 K. The obtained results were fitted by a polynomial temperature dependence. The enthalpy of fusion of LaBr3 was also measured. By combination of these results with the literature data on the entropy, S0
m (LaBr3, s, 298.15 K) and the standard molar enthalpy of formation, ΔformH0
m (LaBr3, s, 298.15 K), the thermodynamic functions of lanthanum tribromide were calculated up to 1300 K
Dielectric Spectroscopy of (bis)Thiourea Pyridinium Bromide
Authors: Marczak A. , Czarnecki P. , Mielcarek S.
Published: February 2015

Policrystalline (bis)thiourea pyridinium bromide has been studied with dielectric spectroscopy and DSC method. New information about phase transitions in (bis)thiourea pyridinium bromide has been obtained and discussed. Two solid-solid phase transitions (at T2 = 150 K - first order transition of order-disorder type, and T1 = 180 K - second order) have been revealed. A change of the ion dynamics is observed at T2
Electron Momentum Distribution of Terbium by Compton Scattering Technique
Authors: Ahuja B. L. , Malhotra H. , Sharma M.
Published: February 2015

We present the experimental Compton profile of polycrystalline terbium, using 661.65 keV gamma-rays, emitted by 20 Ci137Cs. In the absence of band structure calculations, theoretical computations have been made using renormalised-free-atom (RFA) and free electron based profiles. It is seen that the RFA results with e−-e− correlation correction agree relatively better with the experiment. The data are interpreted in terms of spd-f hybridization in the valence state of terbium. From the RFA profile, we have also derived the cohesive energy of terbium, which is compared with other band structures and experimental investigations. - PACs Nos. 13.60.F, 71.15.Nc, 78.70. -g, 78.70.Ck
Investigation of the Spin Hamiltonian Parameters of Yb3+ in CaWO4 Crystal
Authors: Dong Hui-Ning , Wu Shao-Yi
Published: February 2015

In this paper, the spin Hamiltonian parameters g factors g∥ and g⊥ of Yb3+ and hyperfine structure constants A∥ and A⊥ of 171Yb3+ and 173Yb3+ in CaWO4 crystal are calculated from the two-order perturbation formulae. In these formulae, the contributions of the covalence effects, the admixture between J =7/2 and J =5/2 states as well as the second-order perturbation are included. The needed crystal parameters are obtained from the superposition model and the local structure of the studied system. The calculated results are in reasonable agreement with the observed values. The results are discussed.
Mindo-Forces Study on the Keto-Enol Tautomerism of α-Substituted Acetaldehydes XCH2CH=O (X = H, F, Oh, Cn, NH2, NO2, CH3, CF3, OCH3): Comparison with Acetyl Derivatives
Authors: Al-Halasah Wasim F. , Khalil Salim M.
Published: February 2015

MINDO-Forces calculations with complete geometry optimization have been performed on α- substituted acetaldehydes XCH2CH=O and their enols (X = H, F, OH, CN, NH2, NO2, CH3, CF3, OCH3). All substituents were found to decrease the stability of the acetaldehyde and mostly in the case of electron withdrawing capacity (e. g NO2 and CF3). This agrees with theoretical calculations, except in the case of F. The substituent effects on the stabilities in this study are compared with results obtained from our previous theoretical calculations on acetyl derivatives. Geometrical parameters, electron densities, and Gibbs free energies are reported.
Coherent Response Signals of Dipolar-coupled Spin Systems
Authors: Fung B. M. , Ermakov V. L. , Khitrin A. K.
Published: February 2015

Recently, it has been demonstrated that long pulses of a weak radio-frequency field can generate long-lived coherent NMR signals in bulk liquid crystals, which are systems of dipolar-coupled spins with unresolved conventional spectra. Here we describe this phenomenon in more detail and present results of new experimental investigations and computer simulations. It is shown that such response signals can also be excited when the initial spin state of a system corresponds to dipolar ordering. In addition, results of the application of weak pulses on liquid crystalline systems with heteronuclear dipolar couplings are presented, and the role of overlapping peaks is explored.
New Families of Solitary Pattern Solutions of the Nonlinear Dispersive K(n, m, k) Equations
Authors: Inc Mustafa
Published: February 2015

In this paper we shall derive new solitary pattern solutions of the nonlinear dispersive KdV equation (shortly called K(n,m,k) ) by use of simple methods. The properties of these K(n,m,k) equations are shown in figures.
Study of Aqueous Solution of Sodiumdodecylsulfate and Polyethyleneoxide 10000 by NMR NOESY
Authors: Alvarenga Elson S. de , Lima Cláudio F. , Denadai Ângelo M. L.
Published: February 2015

Two-dimensional Nuclear Overhauser Enhancement SpectroscopY NMR has been applied to study sodiumdodecylsulfate (SDS)/polyethyleneoxide (PEO)/D2O at 10, 20, 25, and 40 °C. The results indicate that PEO interacts preferentially with the surface of the micelle aggregates at 20 and 25 °C, displacing some water molecules from the hydration sphere. At 40 °C the polymer tends to penetrate the interior of the SDS micelle, since its solubility in hydrophobic media increases with temperature.
Travelling And Periodic Wave Solutions Of Some Nonlinear Wave Equations
Authors: Khater A. H. , Hassan M. M.
Published: February 2015

We present the mixed dn-sn method for finding periodic wave solutions of some nonlinear wave equations. Introducing an appropriate transformation, we extend this method to a special type of nonlinear equations and construct their solutions, which are not expressible as polynomials in the Jacobi elliptic functions. The obtained solutions include the well known kink-type and bell-type solutions as a limiting cases. Also, some new travelling wave solutions are found. - PACS: 02.30.Jr; 03.40.Kf
The Effect Of A Magnetic Field Dependent Viscosity On The Thermal Convection In A Ferromagnetic Fluid In A Porous Medium
Authors: Sunil  , Bharti Pavan Kumar , Sharma Divya , Sharma R. C.
Published: February 2015

The effect of the magnetic field dependent (MFD) viscosity on the thermal convection in a ferromagnetic fluid in the presence of a uniform vertical magnetic field is considered for a fluid layer in a porous medium, heated from below. For a ferromagnetic fluid layer between two free boundaries an exact solution is obtained, using a linear stability analysis. For the case of stationary convection, the medium permeability has a destabilizing effect, whereas the MFD viscosity has a stabilizing effect. In the absence of MFD viscosity, the destabilizing effect of magnetization is depicted, but in its presence the magnetization may have a destabilizing or stabilizing effect. The critical wave number and critical magnetic thermal Rayleigh number for the onset of instability is determined numerically for sufficiently large values of the magnetic parameter M1. Graphs are plotted to depict the stability characteristics. The principle of exchange of stabilities is valid for a ferromagnetic fluid heated from below and saturating a porous medium.
Effect Of Rotation On Thermal Instability In Couple-Stress Elastico-Viscous Fluid
Authors: Kumar Pardeep , Lal Roshan , Sharma Poonam
Published: February 2015

The thermal instability of a layer of a couple-stress fluid acted on by a uniform rotation is considered. Following the linearized stability theory and normal mode analysis, the dispersion relation is obtained. For stationary convection it is found that rotation has a stabilizing effect, whereas the couple-stress has both stabilizing and destabilizing effects. It is found that the presence of rotation introduces oscillatory modes in the system. A sufficient condition for the non-existence of overstability is also obtained.
A Novel Class Of Localized Excitations For The (2+1)-Dimensional Higher-Order Broer-Kaup System
Authors: Bai Cheng-lin , Zhao Hong
Published: February 2015

By applying a special B¨acklund transformation, a general variable separation solution for the (2+1)-dimensional higher-order Broer-Kaup system is derived. In addition to some types of the usual localized excitations, such as dromions, lumps, ring solitons, oscillated dromions and breathers, soliton structures can be easily constructed by selecting arbitrary functions appropriately. A new class of localized structures, like fractal-dromions, fractal-lumps, peakons, compactons and folded excitations of this system is found by selecting appropriate functions. Some interesting novel features of these structures are revealed. - PACS numbers: 05.45.-a, 02.30.Jr, 02.30.Ik.
Modulation Instability Of Optical Waves In The Cubic-Quintic Complex Ginzburg-Landau Equation With Fourth-Order Dispersion And Gain Terms
Authors: Hong Woo-Pyo , Park Seoung-Hwan
Published: February 2015

The modulation instability of the one-dimensional cubic-quintic complex Ginzburg-Landau equation with fouth-order dispersion and gain terms, a. k. a., the quintic complex Swift-Hohenberg equation, is investgated. The effects of the fourth-order terms to the modulational instability is studied. We numerically investigate the dynamics of the modulational instability in the presence of the fourthorder dispersion and gain terms. - PACS numbers: 42.65.Tg, 42.81DP, 42.65Sf
Hydrogenic System In Half Space
Authors: Patil S. H.
Published: February 2015

Some structural properties of the energy eigenfunctions of a hydrogenic system in half space, are analysed. Specifically, we have obtained the asymptotic behaviour when the electron is far away from the nucleus, the coalescence property when it is close to the nucleus, the inflection property when it is close to the potential barrier, the property when the nucleus is far away from the barrier, and a virial relation. Simple model wave functions are developed, incorporating these properties which give accurate values for the energies and some other physical quantities, and give a useful understanding of the physical structure of the system.
Electron Spin Resonance Of Vo2+ In Likso4 Single Crystals
Authors: Jain Manu
Published: February 2015

Electron spin resonance of VO2+ doped in LiKSO4 single crystals has been studied at 295 K, using an X-band spectrometer. Three sites have been observed. VO2+ enters the lattice at Li and K substitutional sites. The ESR spectra have been analysed and spin-Hamiltonian parameters evaluated. PACS: 76.30 F
Non-Markovian Dynamic And Nmr Spectra In Solids
Authors: Olszewski M. , Sergeev N. A. , Sapiga A.V.
Published: February 2015

The influence of non-Markov molecular motions on NMR absorption spectra has been investigated. It has been shown that the simple non-Markov model of water molecular motion with fluctuations driven by dichotomic noise very well explains the observed temperature dependence of NMR spectra in the mineral natrolite. - PACS number: 05.40.+j, 33.25.+k, 76.20.+q
1H Nmr Study Of Molecular Motions In Thiourea Pyridinium Nitrate Inclusion Compound
Authors: Grottela M. , Kozak A. , Pajzderska A. , Szczepański W. , Wąsicki J.
Published: February 2015

The proton NMR second moment and spin-lattice relaxation time have been studied for polycrystalline thiourea pyridinium nitrate inclusion compound and its perdeuderated analogues in a wide temperature range. The reorientation of two dynamically different pyridinium cations around their pseudohexagonal symmetry axis taking place over inequivalent barriers have been revealed in the low-temperature phase. Activation parameters for these motions have been derived. A symmetrization of the potential barriers has been observed at the transition from intermediate to the high temperature phase. The motion of thiourea molecules has been also evidenced, but could not be unambiguously described.
Studies Of Orientational Order Of Some Nematogens By Means Of Raman Scattering Spectroscopy
Authors: Chrzumnicka Ewa , Szybowicz Mirosław , Bauman Danuta
Published: February 2015

The orientational behaviour of some liquid crystals with various molecular structures was studied by means of the Raman scattering depolarization method. The Raman scattering spectra of linearly polarized light were recorded as a function of temperature in the nematic phase. On the basis of these spectra the order parameters 〈P2〉 and 〈P4〉 as well as the molecular distribution function were determined. The obtained data were compared with those estimated on the basis of polarized light absorption and emission measurements. The influence of the molecular structure on the orientational order of liquid crystals was discussed.
A New Riccati Equation Rational Expansion Method and Its Application
Authors: Chen Yong , Wangc Qi
Published: February 2015

A Riccati equation rational expansion (RERE) method is presented by a general ansatz, which is a direct and unified algebraic method for constructing multiple and more general travelling wave solutions of nonlinear partial differential equations. It can be implemented in a computer algebraic system. The proposed method is applied to consider the shallow long wave approximation equation and leads to a rich variety of exact solutions, including rational form solitary wave solutions, triangular periodic wave solutions and rational wave solutions.
Nonclassical Potential Symmetries and New Explicit Solutions of the Burgers Equation
Authors: Qin Maochang , Mei Fengxiang , Xu Xuejun
Published: February 2015

Several new nonclassical potential symmetry generators to the Burgers equation are derived. Some explicit solutions, which cannot be derived from the Lie symmetry group of Burgers or its adjoined equation, are obtained by using these nonclassical potential symmetry generators.
Ab initio Calculations of the Nuclear Quadrupole Coupling Constants of BHn = 2,4X+ (X = NH3, PH3, H2O, H2S)
Authors: Partovi Tayyebe , Rafieea Marjan A.
Published: February 2015

The electronic structure and strength of acid-base bonding in the protonated boron-Lewis complexes BHn=2,4X+ (X = NH3, PH3, H2O, H2S) and their neutral parents were studied. The results showed that in the H2BX+ monocations the electron releasing from the donor atom in X to BH3 is significant and more complete than in the other studied complexes. Therefore the bonding between the donor and acceptor in H2BX+ is strongest. To obtain these data, the electric field gradient (EFG) at the quadrupolar nuclei in each complex was calculated. The EFG’s of the boron atom and other quadrupolar nuclei were calculated by the Gaussian 98 program, using the MP2/6-31G** method.
Ion-Solvent Interactions Investigated by Isentropic Compressibility Measurements of Tetraalkylammonium, Copper(I) and Sodium Salts in Binary Mixtures of Acetonitrile and n-Butyronitrile at 298.15 K
Authors: Gill Dip Singh , Kumari Avnesh , Sharma Surinder Kumar , Jauhar Surinder Pal
Published: February 2015

Ultrasonic velocities and densities of binary mixtures of acetonitrile (AN) and n-butyronitrile (n-BTN) with Bu4NBPh4, Bu4 NClO4, Bu4 NI, Bu4NBr, Pr4NBr, Et4NI, Et4NBPh4, NaBPh4, NaClO4 and CuClO4 have been measured in the concentration range 0.0045 - 0.2 mol kg−1 over the entire composition range at 298.15 K. Isentropic compressibilities (Ks) and apparent molal isentropic compressibilities (Ks,ø ) have been calculated. Limiting apparent molal isentropic compressibilities (Ko
s,ø ) have been evaluated and split into the contribution of individual ions, i. e. into (Ko
s,ø )± values. (Ko
s,ø )± for Cu+, Na+ and Br− in all cases is negative and large, for Bu4N+ and Ph4B− positive and large, and for I− and ClO4
− negative only in AN, and becomes positive in binary mixtures of AN and n-BTN for all compositions. The negative (Ko
s,ø )± values for Cu+, Na+ and Br− indicate strong ionsolvent interactions involving electrostatic ion-dipole interactions. The large and positive (Ko
s,ø )± values for Bu4N+ and Ph4B− show some special type of ion-solvent interactions (hydrophobic or dispersion interactions) with AN and n-BTN. The small negative value changing to a small positive value for I− and ClO4 − indicates the change of a weak electrostatic ion-solvent interaction to another weak special interaction. A comparison of (Ko
s,ø )± for Cu+ in some solvent systems shows that the ion-solvent interaction behaviour of Cu+ in AN+ n-BTN is similar to that in AN+ NM, AN+ TEP, BN+ TEP and PY + TEP mixtures but differs from that observed in AN+DMF and AN+DMSO mixtures.
Single Crystal ESR of Copper Doped KHCO3
Authors: Lötz Albert
Published: February 2015

A

The principal components of the g- and -tensor of 63Cu2+ obtained from single crystal ESR spectra of copper doped KHCO3 are gzz = 2.2347(1), gyy = 2.0474(1), gxx = 2.0468(1), Azz = 20.43(2) mT, Ayy = 3.22(1) mT, Axx = 2.63(2) mT. The unique axes of both tensors are parallel and lie in the mirror plane of the point group of the crystal (2/m). The direction of this axis conforms with the expectation from the structure of the first coordination shell of the K+ ions. This provides strong evidence for copper entering the K+ positions without major lattice disturbance. Several of the results presented here are at variance with those of an earlier report on the same subject.
EPR and Optical Absorption Studies of VO2+ Doped Trisodium Citrate Dihydrate Single Crystals
Authors: Karabulut B. , Ilkin I. , Tapramaz R.
Published: February 2015

The electron paramagnetic resonance of VO2+ doped trisodium citrate dihydrate (Na3C6H5O7·2H2O) single crystals and powder has been examined at room temperature. The angular variation of the EPR spectra has shown that two different VO2+ complexes are located in different chemical environments, each environment containing two magnetically inequivalent VO2+ sites in distinct orientations occupying substitutional positions in the lattice and showing a very large angular dependence. The crystalline field around the VO2+ ion is nearly axial. The optical absorption spectrum shows three bands, centered at 24631, 16892, and 12195 cm−1. The spin Hamiltonian parameters and the molecular orbital coefficients are calculated from the EPR and optical data, and result are discussed.
Quantum Chemical Simulation of Relaxation and Thermally Stimulated Processes: a Vibration Excitation-relaxation Stochastic Optimization
Authors: Khavryuchenko Volodymyr D. , Khavryuchenko Oleksiy V. , Lisnyak Vladyslav V.
Published: February 2015

A new method for theoretical examination of thermal inter-conversions via the space structure vibration excitation-relaxation stochastic optimization method has been proposed. The software to perform implementation of the methodology has been developed and tested on a silica 27SiO2 cluster. A set of thermodynamically probable space structures of amorphous silica particles and temperatures of their inter-conversions has been simulated. The simulated space structures have been verified by comparison of calculated inelastic neutron scattering spectra of different highly dispersed silicas with experimental ones.
The Frequency Dependence of the Conductivity and Dielectric Relaxation of [(CH2)3(NH3)2]Cu(II)Cl4
Authors: Mostafa Mohga F. , Youssef Ahmed A. A. , Montasser Samy S. , Khyami Shaima S.
Published: February 2015

The structural, dielectric and conductive properties of [(CH2)3(NH3)2]Cu(II)Cl4 have been studied. The material shows an order-disorder transition at T1 = (333±2) K and a ferroelectric phase transitions at T2 = (434±3) K. Results of differential thermal analysis, infrared spectroscopy, X-ray diffraction, AC conductivity and permittivity measurements are reported and discussed. The conductivity results are interpreted in terms of barrier hopping at low and intermediate temperatures, and band-type conduction at high temperatures. - PACS: 81.05.-t, 77.22.-d