bluuebunny/crossref_metadata_2025 huggingface dataset:
Semiempirical Calculations on the Dipole Moment Enhancement in the Solid State
Authors: Raabe Gerhard
Published: February 2015

The enhancement of the molecular dipole moment under the influence of the crystal lattice relative to the value for the corresponding isolated molecule has been calculated for the three low-pressure polymorphs of glycine using the semiempirical MINDO/3 Hamiltonian. In these calculations the influence of the lattice on an arbitrarily chosen reference molecule has been included by modifying the diagonal elements of the Hcore matrix. Starting from a set of atomic charges calculated for the isolated molecule an initial crystal lattice had been set up and included into the calculation of new self-consistent (SCF) charges for the reference molecule. The resulting set of new SCF charges was then used to replace the lattice charges from the preceding run, and a new SCF calculation was performed. This iterative process was continued until the difference between the electronic energies and the sum of the absolute values of the differences between the atomic charges from two subsequent SCF calculations was lower than 10−5 eV and 10−5 e0, respectively. The results agree nicely with the experimental data obtained by other authors for α-glycine.
Investigation of the Spin Hamiltonian Parameters and the Local Structure of Two Ni3+ Centers in KTaO3
Authors: Wu Shao-Yi , Dong Hui-Ning , Wei Wang-He
Published: February 2015

The spin Hamiltonian anisotropic g factors g∥ and g⊥ and the local structures of the Ni3+ centers I and II in KTaO3 are theoretically investigated by using the perturbation formulas of the spin Hamiltonian parameters for 3d7 ions in tetragonally distorted octahedrons and dodecahedrons. By analyzing the electron paramagnetic resonance data of the studied systems, the centers I and II can be attributed to Ni3+ ions occupying octahedral Ta5+ (associated with a nearest-neighbour oxygen vacancy VO along the C4 axis) and the dodecahedral K+ (associated with a nearest-neighbour interstitial oxygen OI along the C4 axis) sites, respectively. Based on these studies, it is found that at the center I the impurity Ni3+ is displaced away from VO by ΔZI ≈ −0.31(2) Å along the C4 axis. At the center II a large off-center displacement, ΔZII ≈ 1.12(2) Å , towards the OI along the C4 axis is obtained, due to Ni3+-OI covalent bonding.
Nutation Spectra of Nuclear Quadrupole Resonance in Off-Resonance Conditions
Authors: Sinyavsky Nicolay , Mackowiak Mariusz
Published: February 2015

The modes of recording the multidimensional NQR nutation spectra have been analyzed using different off-resonance methods. A method of recording the nutation spectra in off-resonance conditions, based on optimal filtration, has been proposed. For the first time, an experimental spectrum of 3D-35Cl NQR nutation of chloral hydrate is presented.
Synthetic, Infrared, 1Hand 13CNMR Spectral Studies on N-(p-Substituted Phenyl)-p-Substituted Benzenesulphonamides, p-X’C6H4SO2NH- (p-XC6H4), where X’ or X = H, CH3, C2H5, F, Cl or Br
Authors: Gowda B. Thimme , Jayalakshmi K. L. , Shetty Mahesha
Published: February 2015

Thirty N-(p-substituted phenyl)-p-substituted benzenesulphonamides of the general formula, p-X’C6H4SO2NH(p-XC6H4), where X’ or X = H, CH3, C2H5, F, Cl or Br, are synthesised and their infrared spectra in the solid state and 1H and 13C NMR spectra in solution are measured. The N-H stretching vibrational frequencies, νN−H vary in the range 3334 - 3219 cm−1, while the asymmetric and symmetric SO2 vibrations appear in the ranges 1377 - 1311 cm−1 and 1182 - 1151 cm−1, respectively. The compounds exhibit S-N and C-N stretching vibrational absorptions in the ranges 937 - 898 cm−1 and 1310 - 1180 cm−1, respectively. There are no particular trends in the variation of these frequencies on substitution with either electron withdrawing or electron donating groups. The 1H and 13C chemical shifts of N-(p-substituted phenyl)-p-substituted benzenesulphonamides,

are assigned to various protons and carbons of the two benzene rings. Further, incremental shifts of the ring protons and carbons due to -SO2NH(p-XC6H4) groups in the compounds of the formula, C6H5SO2NH(p-XC6H4), and p-X’C6H4SO2- and p-X’C6H4SO2NH- groups in the compounds of the formula, p-X’C6H4SO2NH(C6H5) are computed and used to calculate the 1H and 13C chemical shifts of the parallely substituted compounds of the general formula p-X’C6H4SO2NH(p-XC6H4). The computed values agree well with the observed chemical shifts. The above incremental shifts are found to correlate with the Hammett substituent parameters.
Synthesis and Characterization of Y2O3/SiO2 Composites
Authors: Cannas C. , Casu M. , Mainas M. , Musinu A. , Piccaluga G.
Published: February 2015

Impregnation and deposition-precipitation syntheses have been used to obtain Y2O3/SiO2 samples. In the deposition method, the urea causes the precipitation of yttrium hydroxide, which leads to the formation of yttria nanocrystalline particles in the final composites. Delaying the silica addition up to the visible muddying of the solution, a relevant formation of yttria nanocrystalline particles with average size of about 12 nm is produced. The composites obtained through the impregnation method are amorphous and contain different amounts of yttrium depending on the kind of solvent, the highest concentration being reached using ethanol. In all the samples important interactions at the molecular level among yttrium and silica are revealed, but less important in composites obtained with the deposition precipitation method.
Thermodynamic Properties of Eutectic Silumins Doped by Transition Metals
Authors: Kanibolotsky D. S. , Stukalo V. A. , Lisnyak V. V.
Published: February 2015

The thermodynamic properties of the liquid silumins (Al0.879Si0.121)1−xTrx, where Tr = Cu, Fe, Ni and Ti, have been measured, using the electromotive force method at 1040 K. It has been found that diluted solutions of Fe or Ni in eutectic silumins at Tr molar fractions of 0 < xFe ≤ 0.035 and 0 < xNi ≤ 0.027 are characterized by positive deviations from ideality for aluminium. However, the deviations become negative at increasing of the Tr concentration. However, molten silumins doped by Ti and Cu show negative deviations from Raoult’s law for aluminium at the studied concentrations. Thermodynamic activity of Al in the silumins decreases in the sequence of Fe→Ni→Cu→Ti for the dopants.
On the π-Electron Content of Bonds and Rings in Benzenoid Hydrocarbons
Authors: Gutman Ivan , Morikawa Tetsuo , Narita Susumu
Published: February 2015

The Pauling bond order can be viewed as a measure of the π-electron content of the respective carbon-carbon bond. In benzenoid hydrocarbons its values lie between 0 (in the case of essential single bonds) and 1 (in the case of essential double bonds). If the benzenoid molecule does not possess essential single and double bonds, then the Pauling bond orders are greater than 0 and less than 1, but may assume values arbitrarily close to 0 and 1. The π-electron content of a ring is equal to the sum of the π-electron contents of the carbon-carbon bonds forming this ring. We show that in benzenoid hydrocarbons the π-electron content of any (six-membered) ring lies between 0 and 5.5. If the molecule does not possess essential single and double bonds, then the π-electron content of any ring is greater than 0 and less than 5.5, but may assume values arbitrarily close to 0 and 5.5.
Quantum Entanglement, Interaction, And The Classical Limit
Authors: Durt Thomas
Published: February 2015

Two or more quantum systems are said to be in an entangled or non-factorisable state if their joint (supposedly pure) wave-function is not expressible as a product of individual wave functions but is instead a superposition of product states. Only when the systems are in a factorisable state they can be considered to be separated (in the sense of Bell). We show that whenever two quantum systems interact with each other, it is impossible that all factorisable states remain factorisable during the interaction unless the full Hamiltonian does not couple these systems so to say unless they do not really interact. We also present certain conditions under which particular factorisable states remain factorisable although they represent a bipartite system whose components mutually interact.We identify certain quasi-classical regimes that satisfy these conditions and show that they correspond to classical, pre-quantum, paradigms associated to the concept of particle. - PACS number: O3.65.Bz
Studies Of The G Factor For Cr4+ Ion In Bi4ge3o12 Crystal From Crystal-Field And Charge-Transfer Mechanisms
Authors: Wu Xiao-Xuan , Zheng Wen-Chen , Tang Sheng
Published: February 2015

The complete third-order perturbation formulas of the g factors g|| and g⊥ for 3d2 ions in tetragonal MX4 clusters have been obtained by a cluster approach. In these formulas, in addition to contributions to the g factors from the crystal-field mechanism in the crystal-field theory, the contributions from the charge-transfer mechanism are included. From these formulas, the g factors g|| and g⊥ for a Cr4+ ion in a Bi4Ge3O12 crystal are calculated. The results agree with the observed values. The calculated Δ gi(i = || or ⊥) value due to the charge-transfer is opposite in sign and about 20% greater than that due to the crystal-field mechanism. So, for the 3dn ions having a high valence in crystals, a reasonable explanation of the g factors should take both the crystal-field and charge-transfer mechanisms into account.
Kinetics Of The Radicals Induced In Gamma Irradiated Sulfafurazole: An Epr Study
Authors: Çolak Şeyda , Korkmaz Mustafa
Published: February 2015

The spectroscopic and kinetic features of the radiolytic intermediates produced in gamma irradiated sulfafurazole (SFZ) were investigated at different temperatures in the dose range 5 - 50 kGy using EPR and IR techniques. The imodiation produced two species (A, B) in SFZ. The heights of the peaks were used to monitor the temperature, time dependent and kinetic features of the radical species contributing to the EPR spectrum. The applicability of EPR technique for monitoring radiosterilization of SFZ is discussed. The radiation yield of solid SFZ was found to be very low (G = 0.16), and basing on this it was concluded that SFZ and SFZ containing drugs can be safely sterilized by radiation. The EPR data were used to characterize the contributing radicals produced in gamma irradiated SFZ. No definite difference was observed between unirradiated and irradiated IR spectra of SFZ.
Hot-Atom Chemiluminescence: A Beam Study Of The O(3P) + H2, CH4 Systems
Authors: Kowalski A. , Pranszke B.
Published: February 2015

A beam of fast oxygen atoms in the O(3P) state was collided with H2 and CH4 at 10 - 300 eVlab. Chemiluminescence spectra for the H2 target show OH(A-X) emission, while for the CH4 target OH(A-X) as well as CH(A,B-X) emissions are observed. Excitation functions were obtained. For the H2 target they resemble those of N(4S) + H2 collisions, while for the methane target the OH(A) yield increases with collision energy up to 50 eVCM and later decreases slowly, according to the “billiard ball” model.
Ft-Ir Spectroscopic Study Of Co(1-Propanethiol)2Ni(Cn)4·Benzene Clathrate
Authors: Türköz D. , Kartal Z. , Bahçeli S.
Published: February 2015

By vibrational spectroscopy of the new Hofmann-propanethiol-type clathrate Co(1-propanethiol) 2Ni(CN)4·Benzene it is shown that its structure is similar structure to those of other Hofmanntype clathrates.
Mean Amplitudes Of Vibration Of The Trans-Io2f5
2- Anion
Authors: Baran Enrique J.
Published: February 2015

The mean amplitudes of vibration of the trans-IO2F5
2− anion have been calculated from recently reported spectroscopic and structural data between 0 and 1000 K. Bond peculiarities are discussed in comparison with those of related species.
Critical Properties of Isobaric Processes of Lennard-Jones Gases
Authors: Matsumoto Akira
Published: February 2015

The thermodynamic quantities of Lennard-Jones gases, evaluated till the fourth virial coefficient, are investigated for an isobaric process. A partition function in the T-P grand canonical ensemble Y(T,P,N) may be defined by the Laplace transform of the partition function Z(T,V,N) in the canonical ensemble. The Gibbs free energy is related with Y(T,P,N) by the Legendre transformation G(T,P,N) = −kT logY(T,P,N). The volume, enthalpy, entropy, and heat capacity are analytically expressed as functions of the intensive variables temperature and pressure. Some critical thermodynamic quantities for Xe are calculated and drawn. At the critical point the heat capacity diverges to infinity, while the Gibbs free energy, volume, enthalpy, and entropy are continuous. This suggests that a second-order phase transition may occur at the critical point.
Steady Flow of an Electrically Conducting Incompressible Viscoelastic Fluid over a Heated Plate
Authors: Abd-el-Malek Mina B. , Helala Medhat M.
Published: February 2015

The transformation group theoretic approach is applied to the problem of the flow of an electrically conducting incompressible viscoelastic fluid near the forward stagnation point of a heated plate. The application of one-parameter transformation group reduces the number of independent variables, by one, and consequently the basic equations governing flow and heat transfer are reduced to a set of ordinary differential equations. These equations have been solved approximately subject to the relevant boundary conditions by employing the shooting numerical technique. The effect of the magnetic parameter M, the Prandtl number Pr and the non-dimensional elastic parameter representing the non- Newtonian character of the fluid k on velocity field, shear stress, temperature distribution and heat flux are carefully examined.
MINDO-Forces Study on Substituted Nitromethane ⇋ aci-Nitromethane Tautomerism
Authors: Salim Bareehan M. , Khalil Salim M.
Published: February 2015

MINDO-Forces calculations with complete geometry optimization have been performed on nitromethane, aci-nitromethane and X-substituted nitromethane and aci-nitromethane (X = F, OH, NH2, CH3, CN, CF3, NO2, CHO). It is found that nitromethane is more stable than aci-nitromethane by 9.337 kcal/mol. This agrees with theoretical calculations. Thermodynamically, substituted aci-nitro tautomers are more stable than the corresponding nitromethane, except in case of the substituent F. Geometrical parameters, heats of formation, electron densities, Gibbs free energies and isodesmic reactions are reported.
Electron-phonon Coupling in the 4T2g Excited Electron State of Cs2GeF6:Mn4+
Authors: Avram N. M. , Brika M. G.
Published: February 2015

In the present paper we report on an analysis of the fine structure of the first excited quartet 4T2g of Mn4+ ions which occupy the octahedral site in the Cs2GeF6 host crystal. The dynamic 4T2g⊗(eg+t2g) Jahn-Teller effect is considered in details, including the Ham effect of the reduction of the spin-orbit splitting and displacements of the ligands due to the combined effect of the a1g and eg normal modes of the [MnF6]2− octahedral complex. The electron-phonon coupling constants are evaluated using the experimental spectroscopic data. The value of the Jahn-Teller stabilization energy EJT = 438 cm−1 for the considered complex is estimated from both the Ham effect and the potential energy surface of the 4T2g excited state.
Dielectric Interactions and the Prediction of Retention Times of Pesticides in Supercritical Fluid Chromatography with CO2
Authors: Alvarez Guillermo A. , Baumanna Wolfram
Published: February 2015

A thermodynamic model for the partition of a solute (pesticide) between two immiscible phases, such as the stationary and mobile phases of supercritical fluid chromatography with CO2, is developed from first principles. A key ingredient of the model is the result of the calculation made by Liptay of the energy of interaction of a polar molecule with a dielectric continuum, which represents the solvent. The strength of the interaction between the solute and the solvent, which may be considered a measure of the solvent power, is characterized by a function g = (ε − 1)/(2ε +1), where ε is the dielectric constant of the medium, which is a function of the temperature T and the pressure P. Since the interactions between the nonpolar supercritical CO2 solvent and the slightly polar pesticide molecules are considered to be extremely weak, a regular solution model is appropriate from the thermodynamic point of view. At constant temperature, the model predicts a linear dependence of the logarithm of the capacity factor (lnk) of the chromatographic experiment on the function g = g(P), as the pressure is varied, with a slope which depends on the dipole moment of the solute, dispersion interactions and the size of the solute cavity in the solvent. At constant pressure, once the term containing the g (solvent interaction) factor is subtracted from lnk, a plot of the resulting term against the inverse of temperature yields the enthalpy change of transfer of the solute from the mobile (supercritical CO2) phase to the stationary (adsorbent) phase. The increase in temperature with the consequent large volume expansion of the supercritical fluid lowers its solvent strength and hence the capacity factor of the column (or solute retention time) increases. These pressure and temperature effects, predicted by the model, agree excellently with the experimental retention times of seven pesticides. Beyond a temperature of about 393 K, where the liquid solvent densities approach those of a gas (and hence the solvent strength becomes negligible), a dramatic loss of the retention times of all pesticides is observed in the experiments; this is attributed to desorption of the solute from the stationary phase, as predicted by Le Châtelier’s principle for the (exothermic) adsorption process.
The Local Structure of Molten CdBr2
Authors: Shiwakua Hideaki , Okamoto Yoshihiro , Yaita Tsuyashi , Suzuki Shinichi , Minato Kazuo , Tanidac Hajime
Published: February 2015

The local structure of molten CdBr2 was investigated by high temperature X-ray absorption fine structure (XAFS) analysis. The quartz cell designed for hygroscopic high temperature molten salts was successfully used in the measurement. At room temperature the nearest neighbor Cd2+-Br− distance decreased from 2.71 Å in solid state to 2.60 Å in the molten state. The coordination number decreased from 6 to 4 on melting. The obtained structural parameters showed that (CdBr4)2− is predominant in molten CdBr2.
Synthetic, Infrared, 1H and 13C NMR Spectral Studies on N-(2-/3-Substituted Phenyl)-4-Substituted Benzenesulphonamides, 4-X’C6H4SO2NH(2-/3-XC6H4), where X’ = H, CH3, C2H5, F, Cl or Br, and X = CH3 or Cl
Authors: Gowda B. Thimme , Shetty Mahesha , Jayalakshmi K. L.
Published: February 2015

Twenty three N-(2-/3-substituted phenyl)-4-substituted benzenesulphonamides of the general formula, 4-X’C6H4SO2NH(2-/3-XC6H4), where X’ = H, CH3, C2H5, F, Cl or Br and X = CH3 or Cl have been prepared and characterized, and their infrared spectra in the solid state, 1H and 13C NMR spectra in solution were studied. The N-H stretching vibrations, νN−H, absorb in the range 3285 - 3199 cm−1, while the asymmetric and symmetric SO2 vibrations vary in the ranges 1376 - 1309 cm−1 and 1177 - 1148 cm−1, respectively. The S-N and C-N stretching vibrations absorb in the ranges 945 - 893 cm−1 and 1304 - 1168 cm−1, respectively. The compounds do not exhibit particular trends in the variation of these frequencies on substitution either at ortho or meta positions with either a methyl group or Cl. The observed 1H and 13C chemical shifts of

are assigned to protons and carbons of the two benzene rings. Incremental shifts of the ring protons and carbons due to -SO2NH(2-/3-XC6H4) groups in C6H5SO2NH(2-/3-XC6H4), and 4- X’C6H4SO2- and 4-X’C6H4SO2NH- groups in 4-X’C6H4SO2NH(C6H5) are computed and employed to calculate the chemical shifts of the ring protons and carbons in the substituted compounds, 4-X’C6H4SO2NH(2-/3-XC6H4). The computed values agree well with the observed chemical shifts.
Synthetic and Spectroscopic Studies on N-(i,j-Disubstituted Phenyl)-4- Substituted Benzenesulphonamides, 4-X’C6H4SO2NH(i,j-X2C6H3), where X’ = H, CH3, C2H5, F, Cl or Br; i, j = 2, 3; 2, 4; 2, 5; 2, 6 or 3, 4; and X = CH3 or Cl
Authors: Shetty Mahesha , Gowda B. Thimme
Published: February 2015

Fifty four N-(i,j-disubstituted phenyl)-4-substituted benzenesulphonamides of the general formula 4-X’C6H4SO2NH(i,j-X2C6H3), where X’ = H, CH3, C2H5, F, Cl or Br; i,j = 2,3; 2,4; 2,5; 2,6 or 3, 4; and X = CH3 or Cl, are prepared and characterized and their infrared, 1H and 13C NMR spectra in solution are studied. The N-H stretching vibrations νN−H absorb in the range 3305 - 3205 cm−1, while the asymmetric and symmetric SO2 vibrations vary in the ranges 1377 - 1307 cm−1 and 1184 - 1128 cm−1, respectively. The N-(i,j-disubstituted phenyl)-4-substituted benzenesulphonamides show C-S, S-N and C-N stretching vibrations in the ranges 844 - 800 cm−1, 945 - 891 cm−1 and 1309 - 1170 cm−1, respectively. The compounds do not exhibit particular trends in the variation of these frequencies on substitution either at ortho or meta positions with either a methyl group or Cl. The observed 1H and 13C chemical shifts of

are assigned to protons and carbon atoms of the two benzene rings. Incremental shifts of the ring protons and carbon atoms due to -SO2NH(i,j-X2C6H3) groups in C6H5SO2NH(i,j-X2C6H3) and 4-X’C6H4SO2NH- groups in 4-X’C6H4SO2NH(C6H*) are computed and employed to calculate the chemical shifts of the ring protons and carbon atoms in the substituted compounds 4-X’C6H4SO2NH(i,j-X2C6H3). The different methods of calculation lead to almost the same values in most cases and agree well with the observed chemical shifts, indicating the validity of the principle of additivity of the substituent effects with chemical shifts in these compounds.
1H NMR, 31P NMR and Raman Study of CaHPO4 and SrHPO4
Authors: Louati B. , Guidara K. , Gargouri M. , Fourati M.
Published: February 2015

CaHPO4 and SrHPO4 were investigated using Raman, 1H NMR and 31P NMR techniques to study the environment of their PO3−
4 tetrahedra and the percentage of mobile protons. 1H NMR spectra at room temperature suggest the presence of three types of protons, in agreement with RX investigation. The percentage of mobile protons in SrHPO4 is greater than in CaHPO4 because Sr2+ is bigger than Ca2+. 31P NMR spectra at room temperature show two lines in the spectrum of SrHPO4, revealing an equal environment of two sets of pairs of PO3−
4 . The 31P NMR spectrum of CaHPO4, however, exhibits three lines. This result was confirmed using a cross polarization (CP) sequence program. The first peak is attributed to the first set of pairs of P(1)O4 units and the two other ones to P(2)O4 and P(2)O4 units.
Dynamics of Solitary-Waves in the Higher Order Korteweg –De Vries Equation Type (I)
Authors: Hong Woo-Pyo
Published: February 2015

We find new analytic solitary-wave solutions of the higher order wave equations of Korteweg - De Vries (KdV) type (I), using the auxiliary function method. We study the dynamical properties of the solitary-waves by numerical simulations. It is shown that the solitary-waves are stable for wide ranges of the model coefficients. We study the dynamics of the two solitary-waves by using the analytic solution as initial profiles and find that they interact elastically in the sense that the mass and energy of the system are conserved. This leads to the possibility of multi-soliton solutions of the higher order KdV type (I), which can not be found by current analytical methods. - PACS numbers: 03.40.Kf, 02.30.Jr, 47.20.Ky, 52.35.Mw
New Analytical Solutions to the Nonlinear Schrödinger Equation Model
Authors: Zhang Yuanyuan , Zheng Ying , Zhang Hongqing
Published: February 2015

In this paper, new analytical solutions of the nonlinear Schrödinger equation model are obtained. The properties of the new exact solutions are shown by some figures.
Molecular Dynamics Simulation Studies of p-Xylene in OH-free Si-MCM-41
Authors: Nanok Tanin , Bopp Philippe A. , Limtrakul Jumras
Published: February 2015

We report on modeling efforts and molecular dynamics computer simulations of the structure and self-diffusion of p-xylene in OH-free Si-MCM-41 as a function of loading. Both the guest molecules and Si-MCM-41 are modeled as flexible entities. With this newly developped intermolecular force field the average potential energy of p-xylene in the pore increases with increasing loading. The adsorption of p-xylene in MCM-41 is primarily associated with the van der Waals interactions of the model, whereas the contribution from electrostatic interactions is relatively small (about 2 kcal/mol), in accordance with other aromatic hydrocarbons adsorbed in zeolite catalysts. The calculated selfdiffusion coefficients of p-xylene in Si-MCM-41 are well comparable with diffusion coefficients of pyridine in MCM-41 and of the same order of magnitude as in liquid p-xylene. Increasing the loading results in non-negligible mutual p-xylene interaction, thus leading to a decrease of the self-diffusion coefficient.
Determination of Force Constants of Octahedral XY6 Molecules by the GF Matrix Method
Authors: Ucun Fatih , Şengül M. Gökhan
Published: February 2015

The force constants of the internal coordinates of octahedral XY6 molecules and complex ions were calculated by using the GF matrix method. The matrix solutions were found by means of a computer program using the Newton-Raphson method. From the calculations it has been observed that the bond stretch force constants of octahedral XF6 molecules and XY6 complex ions having the same centre X atom decrease with the increasing molar mass of the centre X atom for the former and the ligand Y atom for the latter, respectively. This was attributed to the slowing down of the molecule with increasing molar mass of the molecule as the whole. In addition we have concluded that the difference of squares of the vibration frequencies ν1 and ν2 of octahedral XY6 complex ions decreases with the increasing mass of the Y atom since the interaction force constant of these ions decreases with the increasing mass.
Theoretical Studies of the Optical Spectra and EPR Parameters of Trigonal Yb3+ Center in KMgF3 and KZnF3 Crystals
Authors: Dong Hui-Ning , Wu Shao-Yi , Cai Xue-Mei , Chen Wei-Dong
Published: February 2015

The optical spectra and EPR parameters of trigonal Yb3+ centers in KMgF3 and KZnF3 crystals are calculated in a unified way, based on the crystal-field theory. The results agree reasonably with the observed values. The results are discussed.
Photophysical Properties of Fluorescent Copolymers of Methylmethacrylate for Use in Liquid Crystalline Systems
Authors: Grabchev Ivo , Sali Seher
Published: February 2015

The free radical copolymerisation of five fluorescent 4-allylamino-N-phenyl-substituted 1,8-naphthalimide dyes (MDs) with methylmethacrylate (MMA) has been investigated. The utility of the copolymers prepared as fluorescent component in polymer/liquid crystal systems has been investigated. The basic photophysical properties of monomeric dyes, poly(MMA-co-MD) and poly(MMAco- MD)/liquid crystal mixtures are discussed. The influence of poly(MMA-co-MD) on the phase transition temperature from the nematic to the isotropic state of poly(MMA-co-MD)/liquid crystal mixtures have also been investigated.
Aromatic C-H Bond Rupture; a Density Functional, B3LYP, Study
Authors: Kubba Rehab M.
Published: February 2015

Unrestricted Density Functional (B3LYP) calculations with the 6-311G(d) basis were done for benzene (C6H6) with successive elongation of one C-H bond. Gradual increase in the total energy resulted til C-H bond length of about 3.7 Å , followed by a sudden decrease in energy on further elongation of the bond. The estimated activation energy for the reaction was 152.346 kcal/mol, much higher than the value calculated with the semiempirical PM3 method.
Mean Amplitudes of Vibration of [NH3F]+ and [NH3Cl]+
Authors: Baran Enrique J.
Published: February 2015

The mean amplitudes of vibration of [NH3F]+ and [NH3Cl]+ were calculated from known spectroscopic and structural data in the temperature range between 0 and 1000 K. The results are compared with those of related species and the bond peculiarities are also briefly discussed. Mean amplitude values for the NH4+ cation, at some selected temperatures, are also reported.
Dynamics of Solitary-waves in the Coupled Korteweg-De Vries Equations
Authors: Hong Woo-Pyo , Kim Jong-Jae
Published: February 2015

We find new analytic solitary-wave solutions, having a nonzero background at infinity, of the coupled Korteweg-De Vries equation, using the auxiliary function method. We study the dynamical properties of the solitary-waves by numerical simulations. It is shown that the solitary-waves can be stable or unstable, depending on the coefficients of the model. We study the interaction dynamics by using the solitary-waves as initial profiles to show that the mass and energy of the coupled Korteweg- De Vries can be conserved for a negative third-order dispersion term. - PACS numbers: 03.40.Kf, 02.30.Jr, 47.20.Ky, 52.35.Mw
Some Properties of the Elliptic Ordinary Differential Equation
Authors: Liu Shikuo , Fu Zuntao , Liu Shida , Wang Zhanggui
Published: February 2015

In this paper, some properties of the elliptic ordinary differential equation, which can be used to find travelling wave solutions of nonlinear evolution equations, are given. - PACS: 03.65.Ge
Time-periodic Heating of a Rotating Horizontal Fluid Layer in a Vertical Magnetic Field
Authors: Bhadauria Beer Singh
Published: February 2015

Thermal instability in a horizontal layer of an electrically conducting fluid heated from below has been investigated under the effects of uniform rotation about a vertical axis and an applied uniform vertical magnetic field. The temperature field between the walls of the fluid layer consists of two parts; a steady part and a time-dependent part, which varies periodically. The effect of modulation of the walls temperature on the onset of convection has been studied using Floquets theory. Stabilizing and destabilizing effects on the onset of convective instability have been found. Some comparisons have been made. - 2000 Mathematics Subject Classification: 76E06, 76R10.
Photophysical Properties of Amino- and Dimethylamino Salicylates in Neat and Binary Solvent Mixtures
Authors: Aleksiejew Marek , Józefowicz Marek , Heldt Janina R.
Published: February 2015

The solvation characteristic of 2-methoxy-4-aminobenzoic acid methyl ester (MABAE) and 2- methoxy-4-dimethylaminobenzoic acid methyl ester (MDABAE) in the S0, S1(LE) and S1(ICT) states has been determined by means of solvatochromic shifts in neat and binary solvent mixtures. The multiple linear regression analysis of Kamlet et al. indicates that non-specific dielectric dipoledipole and specific hydrogen-bonding interactions play almost an equal role in defining the position of the absorption and fluorescence maxima. On the basis of the performed analysis of normalized solvatochromic shifts, it has been shown that both solutes are preferentially solvated. For cyclohexane-ethanol (CH-EtOH) binary mixtures the preferential solvation characteristics in the S0, S1(LE) and S1(ICT) states are determined predominantly by the hydrogen-bonding interactions. For both molecules under study the electric dipole moment in the S0, S1(LE) and S1(ICT) states as well as the outer-sphere solvent reorganization energy (λout), intramolecular reorganization energy (λin), and destabilization energy (Edest.) have been determined.
On a Generating Function and its Probability Distributions. A Contribution to the Theory of Transition Rates I
Authors: Kupka Hans
Published: February 2015

A function of two complex variables with two real parameters a and b is described, which generates a sequence of probability distributions of two integer variables m ≥ 0 and n ≥ 0. Closed expressions for the special b = 0 and general case b≠ 0 and recurrence equations for calculating the probability distributions are derived. The probability distribution for m = 0 and a large enough is qualitatively bell-shaped, and that for m ≠ 0 has multiple peak structures. In both cases, the b parameter influences solely the skewness of the curves. For small a values, the distributions fall rapidly from a value of nearly one, decreasing by a factor of 1010 or more as n increases from zero to n = 10. The influence of the b parameter on their properties can be pronounced. Finally, we note an important property of the distributions when two or several of them are convoluted with one another. The result is expressed in terms of an addition theorem in respect to the parameter a and describes a multidimensional distribution.
Two-Dimensional Nutation NQR Broad-Line Spectra in Oriented Samples
Authors: Sinyavsky Nicolay , Korneva Irina , Ostafin Michał , Nogaj Bolesław , Maćkowiak Mariusz
Published: February 2015

The NQR nutation method to determine the electric field gradient asymmetry parameter η in systems, where the resonance line is so broad that the radio frequency field can excite only a portion of the nuclear spins, is presented. In this situation, the recently developed spectroscopic methods are not applicable. Two-dimensional nutation NQR spectra of oriented powders are calculated and used to determine η at particular frequencies along a broad NQR line. The proposed method is useful for single crystals, oriented powders, glasses, and disordered systems even for small values of the asymmetry parameter. Therefore it can be used to evaluate fluctuations in η and the quadrupole coupling constant e2qQ due to inhomogeneities. We demonstrate the application of this method to oriented chalcogenide semiconducting glasses.
New Exact Solutions for Two Nonlinear Equations
Authors: Yang Zonghang
Published: February 2015

Nonlinear partial differential equations are widely used to describe complex phenomena in various fields of science, for example the Korteweg-de Vries-Kuramoto-Sivashinsky equation (KdV-KS equation) and the Ablowitz-Kaup-Newell-Segur shallow water wave equation (AKNS-SWW equation). To our knowledge the exact solutions for the first equation were still not obtained and the obtained exact solutions for the second were just N-soliton solutions. In this paper we present kinds of new exact solutions by using the extended tanh-function method.
Multisoliton Excitations for the Kadomtsev-Petviashvili Equation
Authors: Ma Zheng-Yi , Hua Guo-Sheng , Zheng Chun-Long
Published: February 2015

By means of the standard truncated Painlevé expansion and a special Bäcklund transformation, some exact multisoliton solutions are derived for the Kadomtsev-Petviashvili equation. The evolution properties of the multisoliton excitations are investigated and some novel features or interesting behaviors are revealed. The results show that four straight-line solitons are annihilated or produced with the time increases, which is very similar to the completely nonelastic collision among electrons and positrons.
Bell-Like and Peak-Like Loop Solitons in (2+1)-Dimensional Dispersive Long Water-Wave System
Authors: Zhu Hai-Ping , Zheng Chun-Long , Fang Jian-Ping
Published: February 2015

Starting from an extended mapping approach, a new type of variable separation solution with arbitrary functions of the (2+1)-dimensional dispersive long water-wave (DLW) system is derived. Then based on the derived solution, we reveal some new types of loop solitons such as bell-like loop solitons and peak-like loop solitons in the (2+1)-dimensional DLW system. - PACS numbers: 05.45.Yv, 03.65.Ge
Zhang – Zhang Polynomial of Multiple Linear Hexagonal Chains
Authors: Gutman Ivan , Borovićanin Bojana
Published: February 2015

An explicit combinatorial expression is obtained for the Zhang-Zhang polynomial (also known as “Clar cover polynomial”) of a large class of pericondensed benzenoid systems, the multiple linear hexagonal chains Mn,m. By means of this result, various problems encountered in the Clar theory of Mn,m are also resolved: counting of Clar and Kekulé structures, determining the Clar number, and calculating the sextet polynomial.
Studies of the Angular Distortion around Ti3+ on the Trigonal (2a) Al3+ Site of LaMgAl11O19
Authors: Dong Hui-Ning , Chen Wei-Dong
Published: February 2015

The angular distortion around the impurity Ti3+ on the trigonal (2a) Al3+ site of LaMgAl11O19 is theoretically studied from the perturbation formulas of the anisotropic g factors, g|| and g⊥, for a 3d1 ion in trigonally distorted octahedra. Based on the studies, the metal-ligand bonding angle is found to increase from θH in the host (2a) Al3+ site to θ in the impurity center by about 2◦, due to the local tightness around the larger Ti3+ replacing the smaller Al3+. The theoretical results based on the above angular distortion are in reasonable agreement with the observed values.
Bonding, Electron Densities and Vibration Frequencies of [3]-, [4]-, [5]- and [6]-Radialenes; a B3LYP Density Functional Study
Authors: Shanshal Muthana , Kubba Rehab M.
Published: February 2015

B3LYP density functional treatment is reported for the [3]- to [6]-radialene. For the first two molecules the corresponding Dnh symmetry resulted from the treatment. For the [5]-radialene, the completely planar D5h structure was found energetically a non-minimal configuration showing two imaginary vibrations. An almost planar C1 structure of [5]-radialene emerged as the stable species. As for [6]-radialene, the planar D6h structure proved to be a non-minimal structure too, showing three imaginary vibrations. The D3d chair form was most stable, followed by a twisted boat form of the molecule. The chair form of [6]-radialene was more stable than the twist boat form by 0.9 kcal/mol. Variation of the bond lengths, of A1g (νCC and νCH) vibration frequencies as well as of the total (ρtot) and σ (ρσ ) electron densities for the four molecules, compared with those of ethylene, is discussed. To explain the results, a bonding model for the radialene rings is suggested, which assumes an sp hybridization of the ring atoms in [3]- and [4]-radialenes going over to sp2 hybridization in [5]- and [6]-radialenes.
Some Exact Analytical Solutions to the Inhomogeneous Higher-Order Nonlinear Schrödinger Equation Using Symbolic Computation
Authors: Li Biao , Chen Yong
Published: February 2015

In this paper, the generalized projective Riccati equation method is extended to investigate the inhomogeneous higher-order nonlinear Schrödinger (IHNLS) equation including not only the group velocity dispersion and self-phase-modulation, but also various higher-order effects, such as the third-order dispersion, self-steepening and self-frequency shift. With the help of symbolic computation, a broad class of analytical solutions of the IHNLS equation is presented, which include bright-like solitary wave solutions, dark-like solitary wave solutions, W-shaped solitary wave solutions, combined bright-like and dark-like solitary wave solutions, and dispersion-managed solitary wave solutions. From our results, many previously known results about the IHNLS equation can be recovered by means of some suitable selections of the arbitrary functions and arbitrary constants. Furthermore, from the soliton management concept, the main soliton-like character of the exact analytical solutions is discussed and simulated by computer under different parameters conditions.
Fast Fission Assisted Ignition of Thermonuclear Microexplosions
Authors: Winterberg Friedwardt
Published: February 2015

It is shown that the requirements for fast ignition of thermonuclear microexplosions can be substantially relaxed if the deuterium-tritium (DT) hot spot is placed inside a shell of U-238 (Th-232). An intense laser - or particle beam-projected into the shell leads to a large temperature gradient between the hot DT and the cold U-238 (Th-232), driving thermomagnetic currents by the Nernst effect, with magnetic fields large enough to entrap within the hot spot the α-particles of the DT fusion reaction. The fast fission reactions in the U-238 (Th-232) shell implode about 1/2 of the shell onto the DT, increasing its density and reaction rate. With the magnetic field generated by the Nernst effect, there is no need to connect the target to a large current carrying transmission line, as it is required for magnetized target fusion, solving the so-called “stand off” problem for thermonuclear microexplosions. - PACS number: 28.52.-s.
Effect of the Random Field on the Dynamics of Pulsating, Erupting, and Creeping Solitons in the Cubic-Quintic Complex Ginzburg-Landau Equation
Authors: Hong Woo-Pyo
Published: February 2015

It is shown that the dynamics of pulsating, erupting, and creeping (PEC) solitons obtained from the one-dimensional cubic-quintic complex Ginzburg-Landau equation can be drastically modified in the presence of a random background field. It is found that, when the random field is applied to a pulselike initial profile, multiple soliton trains are formed for the parameters of the pulsating and erupting solitons. Furthermore, as the strength of the gain term increases, the multiple pulsating or erupting solitons transform into fixed-shape stable solitons. This may be important for a practical use such as to generate stable femtosecond pulses. For the case of creeping soliton parameters, the presence of the random field does not generate multiple solitons, however, it induces a rapidly twisting or traveling soliton with a fixed-shape, of which stability can be also controlled by the gain term. - PACS numbers: 42.65.Tg, 03.40.Kf, 05.70.Ln, 47.20.Ky.
Some Coherent Excitations for the (2+1)-Dimensional Generalized Broer-Kaup System
Authors: Ma Zheng-Yi , Liu Yu-Lu , Lu Zhi-Ming
Published: February 2015

Using a projective Riccati equation, several types of solutions of the (2+1)-dimensional generalized Broer-Kaup system are obtained, including multiple soliton solutions, periodic soliton solutions and Weierstrass function solutions. From these, two sets of wave packets are expressed as rational functions of elliptic functions. Especially, peculiar wave patterns that are localized in one direction but periodic in the other direction arise by taking the long wave length limit in one spatial variable. Also exponentially localized wave patterns, which differ from the known dromions, are obtained by taking the long wave length limit in both spatial variables. The interactions of two dromions with inelastic and elastic behaviors are presented
EPR and Optical Absorption Studies of VO2+ Doped KH2PO4 and KH3C4O8·2H2O Single Crystals
Authors: Bıyık Recep , Tapramaz Recep
Published: February 2015

VO2+ doped potassium dihydrogen phosphate (KH2PO4) and potassium tetraoxalate (KH3C4O8 · 2H2O) single crystals and powders are examined by electron paramagnetic resonance and optical absorption spectroscopy. Angular variations of KH2PO4 and KH3C4O8 ·2H2O single crystals show four and two different VO2+ sites, respectively. The local symmetry of VO2+ complexes is nearly axial for both host crystals. The optical absorption spectra show three bands. Spin Hamiltonian parameters are measured and molecular orbital coefficients are calculated by correlating EPR and optical absorption data for the central vanadyl ion
Evaluation of the Structure of Amorphous Tungsten Oxide W28O72 by the Combination of Electron-, X-Ray- and Neutron-Diffraction (Three-Beam Experiment)
Authors: Ankele Jürgen , Mayer Joachim , Lamparter Peter , Steeb Siegfried
Published: February 2015

From the combination of quantitative electron-diffraction data with X-ray- and neutron-diffraction data (so-called three-beam experiment) the partial structure factors and pair correlation functions of amorphous sputter deposited W28O72 were determined. On the basis of the experimental atomic distances and coordination numbers, and by comparison with crystalline WO3, a structural model was developed, which consists of twisted WO6 octahedra. Reverse Monte Carlo simulation in accordance with the experimental data was performed to verify the results
Dielectric Relaxation of Mixtures of N-Methylacetamide and N,N-Dimethylformamide Solved in Benzene Using Microwave Absorption Data
Authors: Kumar Raman , Rangra V. S. , Sharma D. R. , Thakur N. , Negi N. S.
Published: February 2015

The dielectric relaxation times τ and dipole moments μ of N-methylacetamide (NMA) mixed with N,N-dimethylformamide (DMF) in benzene solutions have been obtained using standard standing wave microwave techniques and Gopala Krishna’s single frequency (9.90 GHz) concentration variational method at 25, 30, 35, and 40 ◦C. The energy parameters (ΔHε , ΔFε , ΔSε ) for the dielectric relaxation process of mixtures with equal amounts of NMA and DMF have been calculated and compared with the corresponding energy parameters (ΔHη , ΔFη , ΔSη ) for the viscous flow. On the basis of the observations it is found that the dielectric relaxation process can be treated as a rate process like the viscous flow. Solute-solute and solute-solvent types of the molecular associations have been predicted
Exotic Localized Structures of the (2+1)-Dimensional Nizhnik-Novikov- Veselov System Obtained via the Extended Homogeneous Balance Method
Authors: Dai Chao-Qing , Zhou Guo-quan , Zhang Jie-Fang
Published: February 2015

In this paper, we successfully apply the extended homogeneous balance method (EHBM) to derive a new type of variable separation solutions for the (2+1)-dimensional Nizhnik-Novikov-Veselov system. Novel localized coherent structures about multi-valued functions, i.e., special dromion, special peakon and foldon, and the interactions among them are discussed. Moreover, the explicit phase shifts for all the local excitations offered by the quantity U are given and applied to novel interactions among special dromion, special peakon and foldon in detail. - PACS numbers: 05.45.Yv, 02.30.Jr, 02.03Ik
Modulational Instability of the Higher-Order Nonlinear Schrödinger Equation with Fourth-Order Dispersion and Quintic Nonlinear Terms
Authors: Hong Woo-Pyo
Published: February 2015

The modulational instability of the higher-order nonlinear Schrödinger equation with fourth-order dispersion and quintic nonlinear terms, describing the propagation of extremely short pulses, is investigated. Several types of gains by modulational instability are shown to exist in both the anomalous and normal dispersion regimes depending on the sign and strength of the higher-order nonlinear terms. The evolution of the modulational instability in both the anomalous and normal dispersion regimes is numerically investigated and the effects of the higher-order dispersion and nonlinear terms on the formation and evolution of the solitons induced by modulational instability are studied. - PACS numbers: 42.65.Tg, 42.81Dp, 42.65Sf
Blow up of Solution for the Generalized Boussinesq Equation with Damping Term
Authors: Polat Necat , Kaya Doğan
Published: February 2015

We consider the blow up of solution to the initial boundary value problem for the generalized Boussinesq equation with damping term. Under some assumptions we prove that the solution with negative initial energy blows up in finite time
A Simple but Efficient Method for Nonlinear Parameter Estimation Based on Comparing Phase Space Structures
Authors: Matsumoto Kazuhiro , Diebner Hans H.
Published: February 2015

We introduce a simple method for nonlinear parameter estimation based on a structural comparison of target and model attractor. The parameters of the model are adapted by means of minimizing the structural difference of the attractors. For this quantitative comparison histograms derived from a coarse graining of the phase spaces are used. We present a time discrete as well as a continuous example to demonstrate the efficiency of this method. The target attractors are computed from the Hénon map and the Rössler system, respectively. The model systems are chosen to be fairly universal endowed with free parameters that are adapted so that the model attractor resembles the target. The estimations work accurate and acceptably fast up to four parameters