356 research outputs found
Double radiative decay in the Standard Model
Z-boson decay in the Standard Model is
analysed. The distribution function on the invariant masses of the photon and
fermion pairs is calculated in the leading logarithmic approximation. It is
shown that this distribution function has a specific shape of a ``crest''. (To
be published in Mod.Phys.Lett.A)Comment: 6 pages, LaTeX, (the figures are not included), Yaroslavl, Yaroslavl
State University preprint YARU-HE-94/0
Relativistic Energy Density Functional Description of Shape Transition in Superheavy Nuclei
Relativistic energy density functionals (REDF) provide a complete and
accurate, global description of nuclear structure phenomena. A modern
semi-empirical functional, adjusted to the nuclear matter equation of state and
to empirical masses of deformed nuclei, is applied to studies of shapes of
superheavy nuclei. The theoretical framework is tested in a comparison of
calculated masses, quadrupole deformations, and potential energy barriers to
available data on actinide isotopes. Self-consistent mean-field calculations
predict a variety of spherical, axial and triaxial shapes of long-lived
superheavy nuclei, and their alpha-decay energies and half-lives are compared
to data. A microscopic, REDF-based, quadrupole collective Hamiltonian model is
used to study the effect of explicit treatment of collective correlations in
the calculation of Q{\alpha} values and half-lives.Comment: 23 pages, 10 figure
Electrical conductivity of rocks at high pressures and temperatures
The results of studies of the electrical conductivity in the most widely distributed types of igneous rocks, at temperatures of up to 1200 C, at atmospheric pressure, and also at temperatures of up to 700 C and at pressures of up to 20,000 kg/sq cm are described. The figures of electrical conductivity, of activaation energy and of the preexponential coefficient are presented and the dependence of these parameters on the petrochemical parameters of the rocks are reviewed. The possible electrical conductivities for the depository, granite and basalt layers of the Earth's crust and of the upper mantle are presented, as well as the electrical conductivity distribution to the depth of 200 to 240 km for different geological structures
Bulk Nanocrystalline Thermoelectrics Based on Bi-Sb-Te Solid Solution
A nanopowder from p-Bi-Sb-Te with particles ~ 10 nm were fabricated by the
ball milling using different technological modes. Cold and hot pressing at
different conditions and also SPS process were used for consolidation of the
powder into a bulk nanostructure and nanocomposites. The main factors allowing
slowing-down of the growth of nanograins as a result of recrystallization are
the reduction of the temperature and of the duration of the pressing, the
increase of the pressure, as well as addition of small value additives (like
MoS2, thermally expanded graphite or fullerenes). It was reached the
thermoelectric figure of merit ZT=1.22 (at 360 K) in the bulk nanostructure
Bi0,4Sb1,6Te3 fabricated by SPS method. Some mechanisms of the improvement of
the thermoelectric efficiency in bulk nanocrystalline semiconductors based on
BixSb2-xTe3 are studied theoretically. The reduction of nanograin size can lead
to improvement of the thermoelectric figure of merit. The theoretical
dependence of the electric and heat conductivities and the thermoelectric power
as the function of nanograins size in BixSb2-xTe3 bulk nanostructure are quite
accurately correlates with the experimental data.Comment: 35 pages, 24 figures, 4 tables, 52 reference
CIVIL SOCIETY AND STATE: THE INSTITUTION OF PUBLIC CONTROL IN THE LIGHT OF MODERN RESEARCH PRACTICES IN IRKUTSK REGION
The article covers the place and role of the institution of public control in the mechanisms of the interaction of civil society and state. Basing on the sociological surveys conducted in Irkutsk region in 2008-2017, the article grounds the dynamics of formation of public control in the development of civil society in a region. The authors use the mechanisms of public-state partnership to define the concept of "effective public control" over the governmental bodies and municipal authorities. The article shows the tendency of the increasing role of public bodies (civic chambers, public councils) in the decision-making process of the executive branch as well as in the realization of the decisions
Подход к управлению инновационной деятельности предприятий в условиях современного рынка
Описано підходи до управління інноваційною діяльністю, розглянуто етапи управління інноваціями та виділено основні завдання системи управління інноваційною діяльністю підприємства.Described approaches to innovation management, considered the stages of innovation management and highlighted the main objectives of innovation management companies.Описаны подходы к управлению инновационной деятельностью, рассмотрены этапы управления инновациями и выделены основные задачи системы управления инновационной деятельностью предприятия
Search for long lived heaviest nuclei beyond the valley of stability
The existence of long lived superheavy nuclei (SHN) is controlled mainly by
spontaneous fission and -decay processes. According to microscopic
nuclear theory, spherical shell effects at Z=114, 120, 126 and N=184 provide
the extra stability to such SHN to have long enough lifetime to be observed. To
investigate whether the so-called "stability island" could really exist around
the above Z, N values, the -decay half lives along with the spontaneous
fission and -decay half lives of such nuclei are studied. The
-decay half lives of SHN with Z=102-120 are calculated in a quantum
tunneling model with DDM3Y effective nuclear interaction using
values from three different mass formulae prescribed by Koura, Uno, Tachibana,
Yamada (KUTY), Myers, Swiatecki (MS) and Muntian, Hofmann, Patyk, Sobiczewski
(MMM). Calculation of spontaneous fission (SF) half lives for the same SHN are
carried out using a phenomenological formula and compared with SF half lives
predicted by Smolanczuk {\it et al}. Possible source of discrepancy between the
calculated -decay half lives of some nuclei and the experimental data
of GSI, JINR-FLNR, RIKEN are discussed. In the region of Z=106-108 with N
160-164, the -stable SHN is predicted to have
highest -decay half life () using
value from MMM. Interestingly, it is much greater than the recently measured
() of deformed doubly magic
nucleus. A few fission-survived long-lived SHN which are either -stable
or having large -decay half lives are predicted to exist near
, , and .
These nuclei might decay predominantly through -particle emission.Comment: 14 pages, 6 figures, 1 tabl
The Discovery Potential of a Super B Factory
The Proceedings of the 2003 SLAC Workshops on flavor physics with a high
luminosity asymmetric e+e- collider. The sensitivity of flavor physics to
physics beyond the Standard Model is addressed in detail, in the context of the
improvement of experimental measurements and theoretical calculations.Comment: 476 pages. Printed copies may be obtained by request to
[email protected] . arXiv admin note: v2 appears to be identical to v
Effect of fluorosubstitution on the structure of single crystals, thin films and spectral properties of palladium phthalocyanines
In this work, the crystalline structure of single crystals grown by vacuum sublimation of unsubstituted palladium phthalocyanines (PdPc), its tetrafluorinated (PdPcF4) and hexadecafluorinated (PdPcF16) derivatives have been investigated using X-ray diffraction measurements. Two crystalline phases have been identified for PdPc; the molecules in both phases crystallize in stacks with herringbone arrangement in the monoclinic space groups (C2/c for -PdPc; P21/n for -PdPc). Both PdPcF4 and PdPcF16 crystallize in the triclinic P-1 space group, forming stacks of molecules in columnar arrangement with molecules in adjacent columns are aligned parallel to one another. X-ray diffraction measurements have also been used to elucidate the structural features and molecular orientation of thin films of PdPc, PdPcF4 and PdPcF16, grown by organic molecular beam deposition at different substrate temperatures. The effect of fluorosubstitution on UV-visible optical absorption and vibrational spectra of palladium phthalocyanine derivatives is also discussed
The vertex with arbitrary gluon virtualities in the perturbative QCD hard scattering approach
We study the vertex for arbitrary gluon virtualities in
the time-like and space-like regions, using the perturbative QCD hard
scattering approach and an input wave-function of the -meson
consistent with the measured transition form
factor. The contribution of the gluonic content of the -meson is
taken into account, enhancing the form factor over the entire virtuality
considered. However, data on the electromagnetic transition form factor of the
-meson is not sufficient to quantify the gluonic enhancement. We
also study the effect of the transverse momenta of the partons in the
-meson on the vertex, using the modified
hard scattering approach based on Sudakov formalism. Analytic expressions for
the vertex are presented in limiting kinematic regions
and parametrizations are given satisfying the QCD anomaly, for real gluons, and
perturbative QCD behavior for large gluon virtualities, in both the time-like
and space-like regions. Our results have implications for the inclusive decay
and exclusive decays, such as , and in hadronic production processes .Comment: 23 pages, 19 figures (requires revtex4, amssymb, epsf); several typos
corrected, this version now identical to the one accepted for publication in
Phys. Rev.
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