Optical spectroscopy and electronic structure of the GdCux compounds (x = 1, 2, 5)

Optical properties of the GdCu, GdCu2, and GdCu5 compounds with various crystal lattices have been investigated using ellipsometry in a spectral range of 0. 22-16 μm. Theoretical calculations of the electronic structure of these intermetallic compounds have been performed in the approximation of local electron density with the correction for strong electron correlations in a 4f shell of gadolinium ions. Based on the results of calculations, the interpretation of experimental spectra of interband optical conductivity has been proposed. The plasma and relaxation frequencies of conduction electrons have been determined. © 2013 Pleiades Publishing, Ltd

Microscopic Calculation of Total Ordinary Muon Capture Rates for Medium - Weight and Heavy Nuclei

Total Ordinary Muon Capture (OMC) rates are calculated on the basis of the Quasiparticle Random Phase Approximation for several spherical nuclei from 90^Zr to 208^Pb. It is shown that total OMC rates calculated with the free value of the axial-vector coupling constant g_A agree well with the experimental data for medium-size nuclei and exceed considerably the experimental rates for heavy nuclei. The sensitivity of theoretical OMC rates to the nuclear residual interactions is discussed.Comment: 27 pages and 3 figure

Nuclear magnetic relaxation of 3He in contact with an aerogel above the Fermi temperature

The spin kinetics of 3He in an aerogel has been studied above the Fermi temperature. The magnetic relaxation times T 1 and T 2 of adsorbed, gaseous, and liquid 3He in a 95% silica aerogel at a temperature of 1.5 K have been determined as functions of frequency by means of pulse nuclear magnetic resonance. It has been found that the time T 1 is linear in frequency in all three cases, whereas T 2 is independent of frequency. To explain the observed behavior of the longitudinal relaxation rate, a theoretical model of relaxation in the adsorbed layer of 3He taking into account the filamentary structure of the aerogel is proposed. © 2008 Pleiades Publishing, Ltd

Subexponential estimations in Shirshov's height theorem (in English)

In 1993 E. I. Zelmanov asked the following question in Dniester Notebook: "Suppose that F_{2, m} is a 2-generated associative ring with the identity x^m=0. Is it true, that the nilpotency degree of F_{2, m} has exponential growth?" We show that the nilpotency degree of l-generated associative algebra with the identity x^d=0 is smaller than Psi(d,d,l), where Psi(n,d,l)=2^{18} l (nd)^{3 log_3 (nd)+13}d^2. We give the definitive answer to E. I. Zelmanov by this result. It is the consequence of one fact, which is based on combinatorics of words. Let l, n and d>n be positive integers. Then all the words over alphabet of cardinality l which length is greater than Psi(n,d,l) are either n-divided or contain d-th power of subword, where a word W is n-divided, if it can be represented in the following form W=W_0 W_1...W_n such that W_1 >' W_2>'...>'W_n. The symbol >' means lexicographical order here. A. I. Shirshov proved that the set of non n-divided words over alphabet of cardinality l has bounded height h over the set Y consisting of all the words of degree <n. Original Shirshov's estimation was just recursive, in 1982 double exponent was obtained by A.G.Kolotov and in 1993 A.Ya.Belov obtained exponential estimation. We show, that h<Phi(n,l), where Phi(n,l) = 2^{87} n^{12 log_3 n + 48} l. Our proof uses Latyshev idea of Dilworth theorem application.Comment: 21 pages, Russian version of the article is located at the link arXiv:1101.4909; Sbornik: Mathematics, 203:4 (2012), 534 -- 55

THERMAL RADIATION FROM MAGNETIZED NEUTRON STARS: A look at the Surface of a Neutron Star.

Surface thermal emission has been detected by ROSAT from four nearby young neutron stars. Assuming black body emission, the significant pulsations of the observed light curves can be interpreted as due to large surface temperature differences produced by the effect of the crustal magnetic field on the flow of heat from the hot interior toward the cooler surface. However, the energy dependence of the modulation observed in Geminga is incompatible with blackbody emission: this effect will give us a strong constraint on models of the neutron star surface.Comment: 10 pages. tar-compressed and uuencoded postcript file. talk given at the `Jubilee Gamow Seminar', St. Petersburg, Sept. 1994

ОСОБЕННОСТИ РАБОТЫ УБОРОЧНОЙ ТЕХНИКИ НА СЛАБОНЕСУЩИХ ГРУНТАХ В ДАЛЬНЕВОСТОЧНОМ РЕГИОНЕ

The authors based on own researches established actual problems of harvesting in the Amur region: ensuring passability of machines on the waterlogged soil, need of machines adaptivising to technologies of soybean harvesting, transfer of a part of the combine fleet to a caterpillar track, implementation of reloading reducing impact on the soil technologies of harvesting, increase in cost efficiency of mashines use and postharvest drying of grain and corn.Perspective solutions of problems are shown: design development of caterpillar end trucks of combines with the rubber-reinforced tracks (RRT); engineering and production of the soybean-grain harvester with RRT or a set of devices for the grain harvester with RRT as the option transferring it to the category the soybean-grain ones; process development to provide harvesting of soybean heap by the machine with RRT which crush and spread straw across the field simultaneous, to deliver soybean heap to stationary point of postharvest handling for the subsequent separation into seeds, marketable soybean and a soy chaff as valuable protein feed for livestock production, ready for feeding and storage; engineering of the forage harvester with RRT on a block and modular basis, that is based on the multipurpose power mean on RRT with the 4-machine scheme of a hydrostatic power drive of a undercarriager; development of a design of caterpillar blocks with triangular shape of contour; implementation of reloading technologies of harvest operations on system VIMLIFT.Production of harvest transport vehicles should be performed on a block and modular basis - in the form of a complex of self-propelled agricultural machines based on the released multipurpose power module with a set of the replaceable technological adapters providing its loading within a year. The agroterm of corn on grain harvesting should be delayed to later time when grain reaches standard humidity naturally.На основании исследований авторы выявили актуальные задачи уборочных работ в Амурской области: обеспечение проходимости машин по переувлажненной почве, необходимость адаптирования машин к технологиям уборки сои, перевод части комбайнового парка на гусеничный ход, внедрение перегрузочных почвощадящих технологий уборки, повышение экономической эффективности машиноиспользования и послеуборочной сушки зерна колосовых и кукурузы. Показаны перспективные пути решения этих проблем: совершенствование конструкции гусеничных ходовых тележек комбайнов на резиноармированных гусеницах (РАГ); разработка и производство соезернового комбайна на РАГ или комплекта приспособлений к зерноуборочному комбайну на РАГ как опции, переводящей его в разряд соезерновых; разработка технологии, обеспечивающей сбор зерносоевого вороха полевой машиной на РАГ с одновременным измельчением и разбрасыванием соломы по полю, доставку зерносоевого вороха на стационарный пункт послеуборочной обработки для последующего разделения на семенное, товарное зерно и соевую полову как ценный белковый корм для животноводства, готовый для скармливания и хранения; разработка кормоуборочного комбайна на РАГ на блочно-модульной основе, то есть на базе универсального энергосредства на РАГ с 4-машинной схемой объемного гидропривода ходовой части; совершенствование конструкции гусеничных блоков с треугольной формой обвода; реализация перегрузочных технологий уборочных работ по системе ВИМЛИФТ. Производство уборочно-транспортных машин должно осуществляться на блочно-модульной основе - в виде комплекса самоходных сельскохозяйственных машин на базе высвобождаемого гибкого энергомодуля с комплектом сменных технологических адаптеров, обеспечивающих его загрузку в течение года. Агросрок уборки кукурузы на зерно следует перенести на более позднее время, когда зерно естественным образом достигает кондиционной влажности

Cosmic Physics: The High Energy Frontier

Cosmic rays have been observed up to energies $10^8$ times larger than those of the best particle accelerators. Studies of astrophysical particles (hadrons, neutrinos and photons) at their highest observed energies have implications for fundamental physics as well as astrophysics. Thus, the cosmic high energy frontier is the nexus to new particle physics. This overview discusses recent advances being made in the physics and astrophysics of cosmic rays and cosmic gamma-rays at the highest observed energies as well as the related physics and astrophysics of very high energy cosmic neutrinos. These topics touch on questions of grand unification, violation of Lorentz invariance, as well as Planck scale physics and quantum gravity.Comment: Topical Review Paper to be published in the Journal of Physics G, 50 page

Subaru optical observations of the two middle-aged pulsars PSR B0656+14 and Geminga

We carried out a deep subarcsecond BRI imaging of the two middle-aged pulsars to establish their properties in the optical range. Both pulsars are detected at >10 sigma level. Geminga is for the first time reliably detected in the I band with a magnitude of 25.10+/-0.14. We also reanalyze archival ESO/NTT and HST broadband data and find that some published fluxes for Geminga were estimated inaccurately. The resulting dereddened broadband spectra of both pulsars are remarkably similar to each other and show significant flux increases towards the far-UV and near-IR, and a wide flux excess in V-I bands. This suggests a multicomponent structure of the optical emission. The nonthermal power law component of the pulsar magnetospheric origin dominates in the most part of the optical range. For PSR B0656+14 it is compatible with a low energy extension of the power law tail seen in hard X-rays. For Geminga the respective extension overshoots by a factor of 100 the nonthermal optical flux, which has a less steep spectral slope than in X-rays. This implies a spectral break at a photon energy of about 1 keV. The flux increases towards the far-UV are compatible with contributions of the Rayleigh-Jeans parts of the blackbody components from whole surfaces of the neutron stars dominating in soft X-rays. The V-I excess, which is most significant for PSR B0656+14, suggests a third spectral component of still unidentified origin. Faint, a few arcseconds in size nebulae extended perpendicular to the proper motion directions of the pulsars, are seen around both objects in our deepest I band images. They can be optical counterparts of the bow-shock head of Geminga and of the tentative pulsar wind nebula of PSR B0656+14 observed in X-rays.Comment: 15 pages, 8 figures, A&A, accepted. For higher resolution images see http://www.ioffe.ru/astro/NSG/obs/map