Light Neutral Clusters in Supernova Matter

Physics of Atomic Nuclei - The role of weakly bound neutral clusters, such as dineutrons and tetraneutrons, in matter of high density and high temperature is discussed. Under such conditions, which...     

Nondestructive Control of the Surface,Layers, and Charge Carrier Concentration on SiC Substrates and Structures

Technical Physics - Silicon carbide substrates and epitaxial structures are investigated by nondestructive contactless methods. Parameters of the disrupted surface layer and roughnesses are...     

Coadjoint orbits of the group UT(7, <Emphasis Type="Italic">K</Emphasis>)

We classify the irreducible representations and the coadjoint orbits of a unitriangular group of size less than or equal to seven. We classify the subregular orbits of a unitriangular group of arbitrary size. Translated from Fundamentalnaya i Prikladnaya Matematika, Vol. 13, No. 5, pp. 127–159, 2007.     

Ultra-parabolic equations with rough coefficients. Entropy solutions and strong precompactness property

Under some nondegeneracy condition, we show that sequences of entropy and approximate solutions of a semilinear ultra-parabolic equation are strongly precompact in the general case of a Caratheodory flux vector and a diffusion matrix. The proofs are based on localization principles for the parabolic H-measures corresponding to sequences of measure-valued functions. Bibliography: 21 titles. Dedicated to Nina Nikolaevna Uraltseva Translated from Problemy Matematicheskogo Analiza, 41, May 2009, pp. 49–92.     

Density functional and spectroscopic studies of nitrogen inversion in substituted dizocilpines

While developing a synthesis towards tagged dizocilpine (MK‐801) analogues, we observed highly restricted inversion of a nitrogen centre in a number hydroxylamines obtained as key intermediates. These compounds are shown to possess some of the structural elements which are expected to significantly hinder the nitrogen inversion, potentially leading to hydroxylamines with a chiral nitrogen centre. Free energy barriers (ΔG^≠) of the nitrogen inversion were estimated to be ca. 22 kcal mol^?1 at temperatures near 420 K using variable temperature NMR measurements in DMSO‐d₆. Further density functional studies of a number model systems were undertaken in order to better rationalize the measured inversion barriers and follow the role of various structural factors in raising the barrier height of the nitrogen inversion process. Copyright © 2008 John Wiley & Sons, Ltd.     

Area Spaces: First Steps

We show that a Riemannian manifold of dimension at least 3 can be recovered from the space of boundaries of rectifiable integral 2-currents (the “lcycles”) equipped with the filling area distance, and discuss possible approaches to “spaces with area structures”.     

Nonlocal anomaly of the axial-vector current for bound states

We argue that the amplitude does not vanish in the limit of zero quark masses. This represents a new kind of violation of the classical equation of motion for the axial current and should be interpreted as the axial anomaly for bound states. The anomaly emerges in spite of the fact that the one loop integrals are ultraviolet finite as guaranteed by the finite size of bound-state wave functions. As a result, the amplitude behaves like approximately 1/p(2) in the limit of a large momentum p of the current. The observed effect requires the modification of the classical equation of motion of the axial-vector current by nonlocal operators.     

Phase separation and manifestation of nanoscopic nonuniformities in the optical spectra of manganites

The features observed in the frequency and temperature dependences of the optical spectra of doped manganites can be accounted for by assuming the latter to have inhomogeneous phase composition. The spectral response of the optical conductivity of the La_1?xSr_xMnO₃ system was calculated in the effective-medium approximation over a broad range of x variation.     

Canonical and D-transformations in theories with constraints

We describe a class of transformations in a super phase space (we call them D-transformations) which play the role of ordinary canonical transformations in theories with second-class constraints. Namely, in such theories they preserve the form invariance of equations of motion, their quantum analogs are unitary transformations, and the measure of integration in the corresponding Hamiltonian path integral is invariant under these transformations.