On the existence of a homologous series of BamCum+nOy oxides with the cubic structure of the BaCuO2 oxide

Phase relations have been studied in the BaO–CuO_x system in the range of 42.0–83.0 mol.% CuO at P(O₂) = 21 kPa (air) by visual polythermal analysis (VPA), powder X-ray diffraction (XRD), differential thermal analysis (DTA), thermogravimetric analysis (TGA), chemical analysis (CA), and electron diffraction (ED) with simultaneous elemental analysis (EA) in a transmission electron microscope (TEM). The existence of discrete crystallization fields of barium–copper oxides of cation compositions Ba₄Cu₅O_y, Ba₅Cu₆O_y, Ba₇Cu₈O_y, Ba₁₂Cu₁₃O_y, and Ba₂₄Cu₂₅O_y, which have the cubic structure of the BaCuO₂ oxide, is revealed in the studied region of the system. The oxides may be represented as members of a Ba_mCu_m+nO_y homologous series. The BaCuO₂ oxide does not exist in the subsolidus region and does not have its own crystallization field. The oxygen-deficient oxide BaCuO_1.78 of the cation composition (Ba:Cu) 1:1 with the BaCuO₂ cubic structure is found in melted samples of the 50.0 mol.% CuO composition quenched at 1020–1060 °С.     

Variability in production of the vowels /i/ and /a/

A hypothesis on the nature of articulatory targets for the vowels /i/ and /a/ is proposed, based on acoustic considerations and vowel articulations. The conjecture is that positioning of points on the tongue surface in a repetition experiment should be most accurate in the direction perpendicular to the vocal-tract midline, at the acoustically critical point of maximal constriction for each vowel. The hypothesis was tested by: examining x-ray microbeam data for three speakers, conducting a partial acoustical analysis, and performing a modeling study. Distributions were plotted of the midsagittal locations of three tongue points at the time of maximal excursion toward the vowel target for numbers of examples of the vowels, embedded in a variety of phonetic contexts. More variation was found along a direction parallel to the vocal tract midline than perpendicular to the midline, supporting the hypothesis. Statistics on formant values for one subject have been calculated, and pairwise regressions of displacement and formant data have been run. An articulatory synthesizer [Rubin et al., J. Acoust. Soc. Am. 70, 321-328 (1981)] has been manipulated through displacements similar to the subject's articulatory variation. Although articulatory synthesis showed systematic relationships between articulatory relationships and formant frequencies, there were no significant correlations between the subject's measured articulatory displacements and his formant data. These additional results raise questions about the methodology and point to the need for additional work for an adequate test of the hypothesis.     

On the perturbative stability of the QCD predictions for the ratio R=FL/FT in heavy-quark leptoproduction

We analyze the perturbative and parametric stability of the QCD predictions for the Callan–Gross ratio, R(x,Q ²)=F _L /F _T , in heavy-quark leptoproduction. We consider the radiative corrections to the dominant photon–gluon fusion mechanism. In various kinematic regions, the following contributions are investigated: exact NLO results at low and moderate Q ²≲m ², asymptotic NLO predictions at high Q ²≫m ², and both NLO and NNLO soft-gluon (or threshold) corrections at large Bjorken variable x. Our analysis shows that large radiative corrections to the structure functions F _T (x,Q ²) and F _L (x,Q ²) cancel each other in their ratio R(x,Q ²) with good accuracy. As a result, the NLO contributions to the Callan–Gross ratio are less than 10% in a wide region of the variables x and Q ². We provide compact LO predictions for R(x,Q ²) in the case of low x ≪1. A simple formula connecting the high-energy behavior of the Callan–Gross ratio and low-x asymptotics of the gluon density is derived. It is shown that the obtained hadron-level predictions for R(x→0,Q ²) are stable under the DGLAP evolution of the gluon distribution function. Our analytic results simplify the extraction of the structure functions F ₂ ^c (x,Q ²) and F ₂ ^b (x,Q ²) from measurements of the corresponding reduced cross sections, in particular at DESY HERA.     

Slow Oscillations of the Perpendicular Magnetization of the Pt/Co/Ir/Co/Pt Spin Valve

The time dependences of the transfer of the magnetic moment between stable magnetic states of heterostructures with two Pt/Co/Ir/Co/Pt ferromagnetic layers with the perpendicular magnetization have been studied. Spontaneous oscillations of the macroscopic magnetization with a period of several hours are observed after switching the magnetic field to a new value. The phase portrait of the magnetic relaxation corresponds to damped oscillations. The macrospin oscillation may be due to the high nucleation rate of the reverse magnetization phase induced by the exchange and magnetic dipole interaction between the phase nucleation centers, which arise in different layers. The changes in the Zeeman energy of the system under magnetic oscillations are considered.     

Azimuthal asymmetry and ratio R = FL/FT as probes of the charm content of the proton

We study two experimental ways to measure the heavy-quark content of the proton: using the Callan-Gross ratio R(x,Q ²) = F _L /F _T = and/or azimuthal cos(2φ) -asymmetry in deep inelastic lepton-nucleon scattering. Our approach is based on the perturbative stability of the QCD predictions for these two quantities. We resume the mass logarithms of the type α _s ln(Q ²/m ²) and conclude that heavy-quark densities in the nucleon can, in principle, be determined from data on the Callan-Gross ratio and/or azimuthal asymmetry. In particular, the charm content of the proton can be measured in future studies at the proposed Large Hadron-Electron (LHeC) and Electron-Ion (EIC) Colliders.     

Elastic properties of the RIV-RIII rotator phases of alkanes

A model free energy has been constructed to describe the R_IV-R_III rotator phase transition in alkanes in terms of the elastic strains and order parameter. The conditions for the R_IV-R_III phase transition are discussed. From the free energy, the order parameter and the elastic strains are determined. The model free energy describes the first or second order character of the R_IV-R_III transition depending on the strength of the coupling. The elastic properties in the vicinity of the R_IV-R_III transition are discussed on the basis of a free energy expansion. The temperature dependence of the elastic constants is calculated on both sides of the transition. The coupling between the order parameter and elastic stains is shown to have a crucial influence on the phase behavior and the order of the transition.     

Production of the P-wave excited Bc-states through the Z0 boson decays

In Deng et al. (Eur. Phys. J. C 70:113, 2010), we have dealt with the production of the two color-singlet S-wave (c[`(b)])(c\bar{b})-quarkonium states B<sub>c</sub>(|(c[`(b)])₁[¹S₀]?)B_{c}(|(c\bar {b})_{\mathbf{1}}[^{1}S_{0}]\rangle) and B^*_c(|(c[`(b)])<sub>1</sub>[<sup>3</sup>S<sub>1</sub>]?)B^{*}_{c}(|(c\bar{b})_{\mathbf{1}}[^{3}S_{1}]\rangle) through the Z <sup>0</sup> boson decays. As an important sequential work, we make a further discussion on the production of the more complicated P-wave excited (c[`(b)])(c\bar{b})-quarkonium states, i.e. |(c[`(b)])<sub>1</sub>[<sup>1</sup>P<sub>1</sub>]?|(c\bar{b})_{\mathbf{1}}[^{1}P_{1}]\rangle and |(c[`(b)])₁[³P_J]?|(c\bar{b})_{\mathbf{1}}[^{3}P_{J}]\rangle (with J=(1,2,3)). More over, we also calculate the channel with the two color-octet quarkonium states |(c[`(b)])<sub>8</sub>[<sup>1</sup>S<sub>0</sub>]g?|(c\bar{b})_{\mathbf{8}}[^{1}S_{0}]g\rangle and |(c[`(b)])₈[³S₁]g?|(c\bar{b})_{\mathbf{8}}[^{3}S_{1}]g\rangle, whose contributions to the decay width maybe at the same order of magnitude as that of the color-singlet P-wave states according to the naive nonrelativistic quantum chromodynamics scaling rules. The P-wave states shall provide sizable contributions to the B _c production, whose decay width is about 20% of the total decay width \varGamma _{Z⁰? Bc}\varGamma _{Z^{0}\to B_{c}}. After summing up all the mentioned (c[`(b)])(c\bar {b})-quarkonium states’ contributions, we obtain \varGamma _{Z⁰? Bc}=235.9^+352.8_-122.0\varGamma _{Z^{0}\to B_{c}}=235.9^{+352.8}_{-122.0} KeV, where the errors are caused by the main sources of uncertainty.     

Filling of the 3d band of the manganese in GdAl2−xMnxforx < 0.2

X-ray, magnetic, electrical resistivity and ESR studies of GdAl_2?xMn_x compounds were performed. The transition temperatures, effective mass, thermal broadening of resonance linewidth and g-factors were obtained. For low concentration of GdMn₂ in GdAl₂ up to 20%, Mn is nonmagnetic. Increasing of the effective mass and the thermal broadening linewidth ESR with increasing x can be explained by the presence of d-electrons.     

Effects of the temperature and the pressure on the intermediate valence of Ce(In1−xSnx)3

The curve of the lattice constant of samples Ce(In_1-xSn_x)₃ plotted as a function of the composition x deviates from the linear Vegard's law; the deviation is found to be much more eminent at liquid N₂ temperature than at room temperature. Effects of the pressure on the electrical resistivity was found to be very large for a sample with a composition x = 0.5 which is near to the critical value of the occurence of the intermediate valence state of Ce atoms. The atomic volume of Ce atoms is seen to play an important role for the occurence of the intermediate valence state.     

Effect of the α-F̃1 center interaction on the luminescence lifetime of the F center

The presence of α and F′ centers in a F coloured KCl crystal produces an increase of the lifetime of the luminescence excited with F light. One can exclude that the increase of the luminescence lifetime arises from the contribution of an F′ excited state. The increased lifetime is studied at temperatures lower than 80°K and for some α center concentrations as a function of the initial F center concentration. The results are possibly due to the perturbation of the wavefunction of the F excited state by the α centers present after the F → F′ conversion.     

Cr/Ru/PtCo/Ru/PtCo/Ru介质中底层Ru厚度对磁记录特性影响的研究

讨论了Cr/Ru（1）/PtCo（稳定层）/Ru（2）/PtCo（记录层）/Ru（3） 结构的矫顽力Hc_c与层间反铁磁耦合交换场Hex_ex随Ru（1）与Ru（2）厚度变 化的规律.研究发现 ，样品的矫顽力及交换场随Ru（1）厚度增加而增大， 这可能是由Ru（1）hcp结构引起的. 矫顽力及交换场在Ru（2）厚度为08nm处有峰值. 关键词： 磁记录 反铁磁耦合     

The g-factor of the 132+ state in 207Po and the mesonic contribution to the moment of the i132-neutron

The magnetic moment of the $\text{13}\text{2}{}^{\mathrm{+}}$ state in ²⁰⁷Po was determined to be μ = ?0.910 ± 0.014 n.m. An analysis of this value and other known moments of $\text{i}{}_{\mathrm{<mtext>13</mtext><mtext>2</mtext>}}$ neutron states around ²⁰⁸Pb supports the existence of a mesonic contribution of at least ?0.3 n.m. to the moment.     

Compositional dependence of the optical properties of the amorphous GexTe1−x system

Optical absorption at room temperature of vacuum evaporated Ge_xTe_1−x (0.125?x?0.225) amorphous thin films has been studied as a function of composition. It was found that the optical absorption is due to a direct transition. The real and imaginary parts of the dielectric constant were determined. The single-oscillator energy (E_o) and the energy dispersion parameter (E_d) have been calculated and discussed in terms of the Wemple and Di-Domenico model. The relationship between the optical gap, the average heat of atomization and the coordination numbers has been determined. The optical properties of the amorphous thin films do not change monotonically with increasing Ge content. The observed behavior of the optical properties in the range of compositions studied are explained on the basis of the Bond Constraint Theory (BCT) and rigidity theory, which provide a powerful framework for understanding the structure and properties of amorphous materials. The non-monotonic variation of the optical properties indicates that a transition from floppy to rigid occurs in the Ge_xTe_1−x films.     

Effect of the percentage of yttrium oxide on the phase composition of annealed samples of YzBa5Cu7Oy and YzBa3Cu5Oy composition

The phase composition of Y _z Ba₅Cu₇O _y (1) and Y _z Ba₃Cu₅O _y (2) samples with a variable percentage of yttrium up to the stoichiometric composition of the Y _n Ba _m Cu _{m + n} O _y series is investigated by X-ray phase and elemental analyses, electron diffraction, and high resolution imaging in a transmission electron microscope at a temperature of 930°C in the crystallization field of a matrix oxide (Ba: Cu) of 5: 6 composition on the phase diagram of the BaO-CuO _x system at P(O₂) = 21 kPa. The substantial effect of yttrium oxide’s presence on the phase composition of both objects is found, providing evidence of a complex ionic equilibrium within the melt. The fine-domain oxide structure of the YBa₂Cu₃O₆ tetragonal form, which is due to the coexistence of oxides of an Y _n Ba _m Cu _m+n O _y homologous series of (Y: Ba: Cu) 235, 123, and 257 composition is revealed. The domain size for these phases is 20–50 ?. The domains are joined coherently along axis c.     

A study of the properties of core/shell/shell Ag/FeCo/Ag nanoparticles

The properties of heterophase core/shell/shell Ag/FeCo/Ag nanoparticles synthesized via a plasma method that are promising for biological applications are studied. As is established, the core/shell/shell Ag/FeCo/Ag nanoparticles exhibit a superparamagnetic state at room temperature that allows one to manage the hyperthermia process. The magnetic characteristics of core/shell/shell Ag/FeCo/Ag nanoparticles are interpreted by assuming partial oxidation of the surface layer of a ferromagnetic FeCo shell and formation of the antiferromagnetic Co_xFe_1–xО layer on the FeCo surface. The interaction between the surface antiferromagnetic Co_xFe_1–xО layer and the ferromagnetic FeCо shell causes the emergence of the exchange bias in Ag/FeCo/Ag nanoparticles.     

Measurement of the kaon mass difference mL-mS by the two regenerator method

The K⁰ mass difference has been measured by the two regenerator method. The result is: Δm = m_KL ? m_KS = (0. 534 ± 0.003) × 10¹⁰ sec^?1.     

An appraisal of the molecular model for the vk centre

The V_k centre in halide crystals is often described in terms of an X₂^? molecule ion. Recent molecular calculations for the halogen molecule negative ions have enabled a detailed comparison to be made between the theoretical anion and the results from optical and spin resonance studies on the crystals. The optical absorption line widths are naturally dependant on the host lattice, but the excitation energies and spin resonance constants may be readily interpreted in terms of the molecule. Certain anomalies in the spin resonance data for the heteronuclear defects, in particular ClI^? and BrI^?, show that the simple wavefunction constructed from “s” and “p” atomic orbitals does not adequately describe the polarisation of the large halogen atoms, and a more flexible wavefunction will be needed to calculate the spin resonance constants for these ions.