Influence of temperature and time of isothermal holding on the viscosity and crystallization processes of Al-Y melts close to a eutectic structure

We investigate the temperature and time dependences of viscosity of Al₉₉Y₁, Al₉₇Y₃, Al₉₅Y₅ melts in the range from liquidus to 1200°C. By metallographic, XRD, and differential thermal analyses, we study how the time of isothermal holding of melts influences the structure of ingots during hardening.     

Raman spectra of proton order of thin ice Ih film

The polarized Raman spectra of the upper part of a thin ice Ih film were obtained in the range of 150 cm⁻¹ to 3800 cm⁻¹. The spectra showed clear polarization dependence; several new peaks were also observed. The longitudinaloptic–tranverseoptic (LO–TO) splitting of the mode near 220 cm⁻¹ in the translational vibration region was experimentally confirmed at 133 K. The Fermi resonance between the bending overtone (around 3270 cm⁻¹) and symmetry stretching fundamental (around 3350 cm⁻¹) in the stretching vibration region appeared at nearly the same temperature. Results showed that ice XI (i.e. proton‐ordered phase of ice Ih) slowly formed in the upper part of a thin ice Ih film without KOH as the temperature gradually decreased below 133 K. Copyright © 2015 John Wiley & Sons, Ltd.     

Spectroscopy of homogeneous deuterated hydrocarbon films redeposited from a T-10 tokamak plasma discharge

Homogeneous deuterated hydrocarbon films redeposited from a deuterium plasma discharge inside the T-10 tokamak vacuum chamber are studied using photoluminescence methods; EXAFS, EPR, and IR spectroscopies; and temperature measurements. The photoluminescence excitation spectra of sp ³-sp ² nanostructures of tokamak films are compared with those of sp ² nanostructures of C60 fullerite films. The effect of defect states on photoluminescence and its temperature quenching is discussed. It is concluded that the model of temperature luminescence quenching for homogeneous deuterated tokamak films is similar to that for amorphous a-C:H films.     

Phase behavior of charge stablized colloid dispersion with added water soluble polymers

Demixing and colloidal crystallization in the mixture of charge stabilized colloidal poly(methyl methacrylate) particles and soluble poly(ethylene oxide) were investigated by means of synchrotron small-angle X-ray scattering (SAXS) technique. Phase diagram of the mixture was obtained based on visual inspection and SAXS results. The phase behavior is determined as a function of the concentration of the polymer as well as the volume fraction of the colloidal particles. The system shows a one phase region when the concentration of the polymer is low, whereas a two-phase region is present when the concentration of the polymer is larger than a critical concentration at certain volume fraction of the colloids. Interestingly, a face centered cubic colloidal crystalline structure was formed under certain conditions, which has been rarely observed in experiments of colloid-polymer mixtures with competing interactions.     

Revisiting the Synthesis of Functionally Substituted 1,4-Dihydrobenzo[e][1,2,4]triazines

A series of novel 1,4-dihydrobenzo[1,2,4][e]triazines bearing an acetyl or ester moiety as a functional group at the C(3) atom of the 1,2,4-triazine ring were synthesized. The synthetic protocol is based on an oxidative cyclization of functionally substituted amidrazones in the presence of DBU and Pd/C. It was found that the developed approach is suitable for the preparation of 1,4-dihydrobenzo[e][1,2,4]triazines, but the corresponding Blatter radicals were isolated only in few cases. In addition, a previously unknown dihydrobenzo[e][1,2,4]triazolo[3,4-c][1,2,4]triazine tricyclic open-shell derivative was prepared. Studies of thermal behavior of the synthesized 1,4-dihydrobenzo[1,2,4][e]triazines revealed their high thermal stability (up to 240–250 °C), which enables their application potential as components of functional organic materials.     

The mechanism of interlayer exchange coupling in iron-chromium type nanostructures

A mechanism of the interlayer exchange coupling in layered structures of the Fe/Cr(001) type with rough interfaces is proposed. The theory is based on a model of the charge-induced spin density wave (SDW) formed in the chromium layer. It is shown that the effective magnetic coupling between thick ferromagnetic layers arises due to variations of the SDW vector orientation in the antiferromagnetic layer over a characteristic length ζ determined by the exchange stiffness of chromium. A general expression for the effective magnetic coupling energy E(ψ) as a function of the angle ψ between magnetic moments of the ferromagnetic layers is obtained and numerically analyzed for an arbitrary value of the parameter ρζ, where ρ is the density of monoatomic steps on the interface. For ρζ?1, the form of E(ψ) is typical of a model with the “ biquadratic” interaction, while in the case of ρζ?1, the dependence obtained differs significantly. The proposed mechanism is used to interpret the results of measurements of the interlayer exchange coupling in Fe/Cr(001) structures.     

Features of the Electronic Structure of the Bi2Se3 Topological Insulator Digitally Doped with 3d Transition Metals

JETP Letters - We calculate the photoionization cross section of a molecular endohedral that denote as M@CN. We limit ourselves to diatomic molecules. The consideration is much more complex than...     

X-ray Photoelectron Spectroscopy of Imidazolium-Based Zwitterions: The Intramolecular Charge-Transfer Effect

Russian Journal of Physical Chemistry A - We investigate the imidazolium-based zwitterions, 1-butyl-3-methylimidazolium-2-pentafluorophosphate, together with 1-butyl-3-methylimidazolium...     

Tomographic probability representation for quantum fermion fields

Tomographic probability representation is introduced for fermion fields. The states of the fermions are mapped onto the probability distribution of discrete random variables (spin projections). The operators acting on the fermion states are described by fermionic tomographic symbols. The product of the operators acting on the fermion states is mapped onto the star-product of the fermionic symbols. The kernel of the star-product is obtained. The antisymmetry of the fermion states is formulated as a specific symmetry property of the tomographic joint probability distribution associated with the states.