Transient fields for W ions traversing Fe hosts and for Os ions traversing Fe and Ni hosts

Transient field strengths were measured for^{184, 186}W ions traversing thin, magnetized Fe foils with velocities in the range 1.8 ≲ υ/υ₀ ≲ 5.7 (υ₀ = Bohr velocity) and for^{188, 190, 192}Os ions traversing polarized Ni hosts with average velocities 〈υ/υ₀〉 ∼ 4. The present measured transient field strengths, together with previously measured results for W, Os ions, are compared with transient field strength parametrizations, and discussed in terms of microscopic models of the transient field.     

Measurement of scattering rate and minimum conductivity in graphene

The conductivity of graphene samples with various levels of disorder is investigated for a set of specimens with mobility in the range of 1-20x10(3) cm2/V sec. Comparing the experimental data with the theoretical transport calculations based on charged impurity scattering, we estimate that the impurity concentration in the samples varies from 2-15x10(11) cm(-2). In the low carrier density limit, the conductivity exhibits values in the range of 2-12e2/h, which can be related to the residual density induced by the inhomogeneous charge distribution in the samples. The shape of the conductivity curves indicates that high mobility samples contain some short-range disorder whereas low mobility samples are dominated by long-range scatterers.     

X-ray diffraction study of crystals of the organic luminophore Orlyum White 520T

The crystal and molecular structures of two crystal forms (pale yellow form 1 and yellow form 2) of N-[2-(4-oxo-4H-benzo[d][1,3]oxazin-2-yl)phenyl]naphthalene-2-sulfonamide (Orlyum White 520T), which is an organic luminophore with an anomalously high Stokes shift, were determined. Crystal 2 is a solvate with para-xylene. Crystal 1 is a solvent-free form. The molecular geometry in crystal 1 differs from that in 2 only in the orientation of the SO₂ Ar substituent. The bond-length distribution in the planar moiety of the molecule in crystal 1 is virtually identical to that in 2, but the bonds in the NH-SO₂ Ar-bearing benzene ring in crystal 1 are systematically longer than the corresponding bonds in crystal 2. This fact can be attributed to the crystal-packing effects. In 2 the molecules form stacked dimers with π-stacking interactions between two planar conjugated tricyclic systems. The charge transfer in this system accounts for the intensification of the color of these crystals and the observed difference in the optical properties of 1 and 2.     

Construction of discrete-continual models in structure analysis for extreme dynamic loadings

We propose a new method for constructing design models of high-rise buildings and structures, which is based on the treatment of the set of bearing structures as discrete-continual inelastic damageable system admitting large spatial displacements and rotations. We derive a relation for the virtual work functional with respect to increments of integral stress characteristics, which can be viewed as a starting point for solving applied problems of simulation of structural dynamics under the action of extreme forces. To take into account the processes of damage and failure of buildings and structures, we propose a generalized scheme for constructing a nonlinear physical model of deformation on the level of integral stress characteristics in the bearing structures of a storey. As an example of application of this model, we consider the problem of dynamic behavior of a multistorey building under a spatial seismic load.     

Synthesis and Gas-Transport Parameters of Membranes Modified by Star-Shaped Palladium Nanocrystallites

Doklady Physics - Methods for modifying the surface of Pd–23%Ag alloy films and synthesizing nanostar- and nanopore-type palladium coatings, which enhance the hydrogen transport rate, were...