Resonant influence of hypersound on the radiation of an axially channeled electron

Abstract

The spectral intensity of the radiation emitted by an axially channeled electron in a single crystal excited by a longitudinal hypersonic wave propagating along the channeling direction has been calculated for the energy range 10MeV ≤ E ≤ 100 MeV. It has been shown that under the influence of acoustic vibrations excited in the single crystal a resonant intensification of the electron channeling radiation, a variation of its spectral distribution as well as inverse radiative transitions are possible.     

Coarse-graining protein energetics in sequence variables

We show that cluster expansions (CE), previously used to model solid-state materials with binary or ternary configurational disorder, can be extended to the protein design problem. We present a generalized CE framework, in which properties such as energy can be unambiguously expanded in the amino-acid sequence space. The CE coarse grains over nonsequence degrees of freedom (e.g., side-chain conformations) and thereby simplifies the problem of designing proteins, or predicting the compatibility of a sequence with a given structure, by many orders of magnitude. The CE is physically transparent, and can be evaluated through linear regression on the energies of training sequences. We show, as example, that good prediction accuracy is obtained with up to pairwise interactions for a coiled-coil backbone, and that triplet interactions are important in the energetics of a more globular zinc-finger backbone.     

Synthesis of aryl Β-heterylethyl ketones

The decarboxylation of -aroyl--heterylpropionic acids in vacuo leads to the formation of the corresponding ketones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 3, pp. 348–351, March, 1979.     

The Fourier–Faber–Schauder Series Unconditionally Divergent in Measure

We prove that, for every ε ∈ (0, 1), there is a measurable set E ? [0, 1] whose measure |E| satisfies the estimate |E| > 1?ε and, for every function f ∈ C_[0,1], there is ? f ∈ C_[0,1] coinciding with f on E whose expansion in the Faber–Schauder system diverges in measure after a rearrangement.     

Selective reflection by atomic vapor: experiments and self-consistent theory

Selective reflection of laser radiation from the interface between atomic vapor and a dielectric is studied for a wide range of vapor density. A self-consistent model is developed, some analytical results are obtained, as well as a number of curves are computed that are in good agreement with experimental spectra measured in cesium and rubidium vapor cells.     

Universal function for a weighted space $$L^1_{\mu }[0,1]$$

It is shown that there exist such a function \(g\in L^1[0,1]\) and a weight function \(0<\mu (x)\le 1\) that g is universal for the weighted space \(L^1_\mu [0,1]\) with respect to signs of its Fourier–Walsh coefficients.     

Crystal growth of β-Phthalocyanines from the vapour phase in closed ampoules

An influence of temperature gradient, inert gas pressure and pulling rate on the growth parameters of β-phthalocyanine single crystals grown in the closed ampoules is investigated. The morphology and structure — sensitive properties of β-CuPc crystals grown under different conditions are compared.     

Interpolation of functions by the least squares method

We study the norm of a best quadratic trigonometric approximation operator on a finite uniform grid. Dedicated to the memory of my scientific adviser, Professor S. B. Stechkin Translated fromMatematicheskie Zametki, Vol. 66, No. 3, pp. 372–379, September, 1999.     

Structure and energetics of nickel, copper, and gold clusters

The most stable structures of Cu_N, Ni_N, and Au_N clusters with 2≤N≤60 have been determined using a combination of the embedded-atom (EAM), the quasi-Newton, and our own Aufbau/Abbau methods for the calculation of the total energy for a given structure, the structures of the local total-energy minima, and the structure of the global total-energy minimum, respectively. We have employed two well-known versions of the EAM: (1) the ‘bulk’ version of Daw, Baskes, and Foiles and (2) the Voter-Chen version which takes into account also properties of the dimer in the parameterization. The lower-energy structures (also for the smallest) of Cu_N and Ni_N clusters (i.e., structural details as well as symmetry) obtained with the two versions are very similar. Thus, our study supports an universality of the bulk embedding functions for copper and nickel. But for gold clusters the differences between structures calculated with the two different versions of the EAM are significant, even for larger clusters.