Angular forces in the lattice dynamics of diamond crystal lattices

The lattice dynamics of the diamond lattice has been investigated using a model in which the interatomic forces include, in addition to central forces, the angular forces of the type employed by de Launay and Clark, Gazis and Wallis. The 2 models have been applied to silicon and germanium to investigate the phonon dispersion curves in the three symmetry directions of the Brillioun zone. The results are found to be qualitatively in good agreement with experiments.     

A simple extrusion method for the synthesis of aligned silica nanowires using the template of a rigid surfactant mesophase

Long range alignment of silica nanowires has been accomplished by extrusion of a novel surfactant mesophase prior to silica synthesis.     

The reaction of chromate with diphenylcarbazide. I

The mechanism of the classical colour reaction between chromate and carbazide has been studied in solution from various physicochcmical points of view. It has been established from spectral identity that the same red-violet compound is produced in the 3 different reaction systems, chromate-carbazidc, chromate-carbazone and chromous-carbazonc. This leads to the conclusion that tlie chromate-carbazidc reaction is a composite one involving preliminary oxidation followed subsequently by complex formation. Moreover, the actual constituents involved in the reaction have been identified as Cr⁺² on the one hand and carbazone on the other, giving rise to an intensely coloured inner complex compound. The inner complex nature of the coloured product was gauged independently from migration studies and from extraction of the coloured compound by non-polar solvents.     

Search for ZH → l+ l- bb production in 4.2 fb(-1) of pp collisions at sqrt[s] =1 .96 TeV

We present a search for the standard model Higgs boson produced in association with a Z boson in 4.2 fb(-1) of pp collisions, collected with the D0 detector at the Fermilab Tevatron at sqrt[s] =1 .96 TeV. Selected events contain one reconstructed Z → e+ e- or Z → μ+ μ- candidate and at least two jets, including at least one b-tagged jet. In the absence of an excess over the background expected from other standard model processes, limits on the ZH cross section multiplied by the branching ratios are set. The limit at M(H) = 115 GeV is a factor of 5.9 larger than the standard model prediction.     

On Spliced Sequences and the Density of Points with Respect to a Matrix Constructed by using a Weight Function

Ukrainian Mathematical Journal - Following the line of investigation in [Linear Algebra Appl., 487, 22–42 (2015)], for y ∈ ? and a sequence...     

A Molecular Mean Field Theory of Reentrant Phases

The observed phase transition sequence N-S_A-N_re S_re with a lowering in temperature in pure compounds of molecules with a strongly polar end group is reproduced in a mean field model which is taken as an extension of the McMillan potential. This model shows how the dimers in presence of space filling monomers can account for the high temperature S_A phase. As the temperature is lowered, more and more monomers form dimers leaving empty spaces and this initiates an intercalation of dimers belonging to the neighbouring layers. This intercalation is responsible for the lowering of the strength of layering interaction in a McMillan type potential and thus a reentrant nematic phase occurs. This model for the first time successfully accounts for the thickness of the low temperature smectic phase.     

Finite Diagonal Random Matrices

The goal of this article is to extend some results of Popescu (Probab. Theory Relat. Fields 144:179, 2009) in several directions. We establish the limiting spectral distribution (LSD) for r-diagonal matrices under reduced moment conditions compared to those required by Popescu. We also deal with the joint convergence of several sequences of such matrices. In particular, we show that there is a large class of such matrices where the joint limit is not free while the marginals are semicircular. We also consider matrices of the form $X_{n}X_{n}^{T}$ where X _n is a sequence of nonsymmetric r-diagonal random matrices and establish their limiting spectral distribution.