827 research outputs found
Recent developments in the characterization of superconducting films by microwaves
We describe and analyze selected surface impedance data recently obtained by
different groups on cuprate, ruthenate and diboride superconducting films on
metallic and dielectric substrates for fundamental studies and microwave
applications. The discussion includes a first review of microwave data on MgB2,
the weak-link behaviour of RABiTS-type YBa2Cu3O7-d tapes, and the observation
of a strong anomalous power-dependence of the microwave losses in MgO at low
temperatures. We demonstrate how microwave measurements can be used to
investigate electronic, magnetic, and dielectric dissipation and relaxation in
the films and substrates. The impact of such studies reaches from the
extraction of microscopic information to the engineering of materials and
further on to applications in power systems and communication technology.Comment: Invited contribution to EUCAS2001, accepted for publication in
Physica C in its present for
High-statistics measurement of the pion form factor in the rho-meson energy range with the CMD-2 detector
We present a measurement of the pion form factor based on e+e- annihilation
data from the CMD-2 detector in the energy range 0.6<sqrt(s)<1.0 GeV with a
systematic uncertainty of 0.8%. A data sample is five times larger than that
used in our previous measurement.Comment: 18 pages, 10 figures. Added comparison with KLOE measurement, minor
updates. Accepted by PL
Research of the state of internal surfaces of a supercritical water loop after a session of irradiation
Made of austenitic steel at the NSC KIPT, the supercritical water convection loop Loop-1a was running for more than 500 hours in the first experimental session (in 2011). The materials tested in the loop were placed into a stream of water (more than 50 g/s) at a temperature of 350âŠ400°C, a pressure of 23⊠25 MPa, and were irradiated by an electron beam with an energy of 10 MeV. Sediments that emerged on the inner surface of the loop were examined. The sediment mainly consisted of compounds of calcium and iron mixed with other elements. There is a possibility to increase corrosion induced by radiation due to dislocation damage, hydrogenation of metal and under the impact of active oxygen.ĐĐžĐłĐŸŃĐŸĐČĐ»Đ”ĐœĐ° Đ· Đ°ŃŃŃĐ”ĐœŃŃĐœĐŸŃ ŃŃалО ĐČ ĐĐĐŠ Đ„Đ€ĐąĐ ĐœĐ°ĐŽĐșŃĐžŃĐžŃĐœĐ° ĐČĐŸĐŽŃĐœĐ° ĐșĐŸĐœĐČĐ”ĐșŃŃĐčĐœĐ° пДŃĐ»Ń Loop-1a ĐČ ĐżĐ”ŃŃĐŸĐŒŃ Đ”ĐșŃпДŃĐžĐŒĐ”ĐœŃĐ°Đ»ŃĐœĐŸĐŒŃ ŃĐ”Đ°ĐœŃŃ (2011 ŃŃĐș) ĐżŃĐŸĐżŃĐ°ŃŃĐČала ĐżĐŸĐœĐ°ĐŽ 500 ĐłĐŸĐŽ. ĐОпŃĐŸĐ±ĐŸĐČŃĐČĐ°ĐœŃ Ń ĐżĐ”ŃĐ»Ń ĐŒĐ°ŃĐ”ŃŃалО пДŃДбŃĐČалО ĐČ ĐżĐŸŃĐŸŃŃ ĐČĐŸĐŽĐž (ĐżĐŸĐœĐ°ĐŽ 50 Đł/Ń) ĐżŃĐž ŃĐ”ĐŒĐżĐ”ŃĐ°ŃŃŃŃ 350âŠ400°C, ŃĐžŃĐșŃ 23âŠ25 ĐĐĐ° Ń ĐŸĐżŃĐŸĐŒŃĐœŃĐČалОŃŃ Đ”Đ»Đ”ĐșŃŃĐŸĐœĐœĐžĐŒ ĐżŃŃĐșĐŸĐŒ Đ”ĐœĐ”ŃĐłŃŃŃ 10 ĐĐ”Đ. ĐĐŸŃĐ»ŃЎжŃĐČалО ĐČŃĐŽĐșĐ»Đ°ĐŽĐ”ĐœĐœŃ ĐœĐ° ĐČĐœŃŃŃŃŃĐœŃĐč ĐżĐŸĐČĐ”ŃŃ
ĐœŃ ĐżĐ”ŃĐ»Ń, ŃĐșŃ ŃĐșлаЎаŃŃŃŃŃ ĐČ ĐŸŃĐœĐŸĐČĐœĐŸĐŒŃ ŃĐ· ŃĐżĐŸĐ»ŃĐș ĐșĐ°Đ»ŃŃŃŃ Ń Đ·Đ°Đ»ŃĐ·Đ° Đ· ĐŽĐŸĐŒŃŃĐșĐŸŃ ŃĐœŃĐžŃ
Đ”Đ»Đ”ĐŒĐ”ĐœŃŃĐČ. ĐĐŸĐ¶Đ»ĐžĐČĐ” ĐżĐŸŃĐžĐ»Đ”ĐœĐœŃ ĐșĐŸŃĐŸĐ·ŃŃ ĐżŃĐŽ ĐŽŃŃŃ ĐČОпŃĐŸĐŒŃĐœŃĐČĐ°ĐœĐœŃ Đ·Đ° ŃĐ°Ń
ŃĐœĐŸĐș ĐŽĐžŃĐ»ĐŸĐșĐ°ŃŃĐčĐœĐžŃ
ŃŃĐșĐŸĐŽĐ¶Đ”ĐœŃ, ĐœĐ°ŃĐžŃĐ”ĐœĐœŃ ĐČĐŸĐŽĐœĐ”ĐŒ Ń Đ°ĐșŃĐžĐČĐœĐŸĐłĐŸ ĐșĐžŃĐœŃ.ĐĐ·ĐłĐŸŃĐŸĐČĐ»Đ”ĐœĐœĐ°Ń ĐžĐ· Đ°ŃŃŃĐ”ĐœĐžŃĐœĐŸĐč ŃŃалО ĐČ ĐĐĐŠ ЄЀйРŃĐČĐ”ŃŃ
ĐșŃĐžŃĐžŃĐ”ŃĐșĐ°Ń ĐČĐŸĐŽŃĐœĐ°Ń ĐșĐŸĐœĐČĐ”ĐșŃĐžĐŸĐœĐœĐ°Ń ĐżĐ”ŃĐ»Ń Loop-1a ĐČ ĐżĐ”ŃĐČĐŸĐŒ ŃĐșŃпДŃĐžĐŒĐ”ĐœŃĐ°Đ»ŃĐœĐŸĐŒ ŃĐ”Đ°ĐœŃĐ” (2011 ĐłĐŸĐŽ) ĐżŃĐŸŃĐ°Đ±ĐŸŃала Đ±ĐŸĐ»Đ”Đ” 500 Ń. ĐŃĐżŃŃŃĐČĐ°Đ”ĐŒŃĐ” ĐČ ĐżĐ”ŃлД ĐŒĐ°ŃĐ”ŃĐžĐ°Đ»Ń ĐœĐ°Ń
ĐŸĐŽĐžĐ»ĐžŃŃ ĐČ ĐżĐŸŃĐŸĐșĐ” ĐČĐŸĐŽŃ (Đ±ĐŸĐ»Đ”Đ” 50 Đł/Ń) ĐżŃĐž ŃĐ”ĐŒĐżĐ”ŃĐ°ŃŃŃĐ” 350âŠ400°C, ĐŽĐ°ĐČĐ»Đ”ĐœĐžĐž 23⊠25 ĐĐĐ° Đž ĐŸĐ±Đ»ŃŃалОŃŃ ŃлДĐșŃŃĐŸĐœĐœŃĐŒ ĐżŃŃĐșĐŸĐŒ ŃĐœĐ”ŃгОДĐč 10 ĐŃĐ. ĐŃŃĐ»Đ”ĐŽĐŸĐČалО ĐŸŃĐ»ĐŸĐ¶Đ”ĐœĐžŃ ĐœĐ° ĐČĐœŃŃŃĐ”ĐœĐœĐ”Đč ĐżĐŸĐČĐ”ŃŃ
ĐœĐŸŃŃĐž пДŃлО, ĐșĐŸŃĐŸŃŃĐ” ŃĐŸŃŃĐŸŃŃ ĐČ ĐŸŃĐœĐŸĐČĐœĐŸĐŒ Оз ŃĐŸĐ”ĐŽĐžĐœĐ”ĐœĐžĐč ĐșĐ°Đ»ŃŃĐžŃ Đž жДлДза Ń ĐżŃĐžĐŒĐ”ŃŃŃ ĐŽŃŃгОŃ
ŃĐ»Đ”ĐŒĐ”ĐœŃĐŸĐČ. ĐĐŸĐ·ĐŒĐŸĐ¶ĐœĐŸ ŃŃĐžĐ»Đ”ĐœĐžĐ” ĐșĐŸŃŃĐŸĐ·ĐžĐž ĐżĐŸĐŽ ĐŽĐ”ĐčŃŃĐČĐžĐ”ĐŒ ОзлŃŃĐ”ĐœĐžŃ Đ·Đ° ŃŃĐ”Ń ĐŽĐžŃĐ»ĐŸĐșĐ°ŃĐžĐŸĐœĐœŃŃ
ĐżĐŸĐČŃĐ”Đ¶ĐŽĐ”ĐœĐžĐč, ĐœĐ°ĐČĐŸĐŽĐŸŃoжОĐČĐ°ĐœĐžŃ Đž Đ°ĐșŃĐžĐČĐœĐŸĐłĐŸ ĐșĐžŃĐ»ĐŸŃĐŸĐŽĐ°
A phenomenological theory of zero-energy Andreev resonant states
A conceptual consideration is given to a zero-energy state (ZES) at the
surface of unconventional superconductors. The reflection coefficients in
normal-metal / superconductor (NS) junctions are calculated based on a
phenomenological description of the reflection processes of a quasiparticle.
The phenomenological theory reveals the importance of the sign change in the
pair potential for the formation of the ZES. The ZES is observed as the
zero-bias conductance peak (ZBCP) in the differential conductance of NS
junctions. The split of the ZBCP due to broken time-reversal symmetry states is
naturally understood in the present theory. We also discuss effects of external
magnetic fields on the ZBCP.Comment: 12 page
Avalanche Dynamics in Evolution, Growth, and Depinning Models
The dynamics of complex systems in nature often occurs in terms of
punctuations, or avalanches, rather than following a smooth, gradual path. A
comprehensive theory of avalanche dynamics in models of growth, interface
depinning, and evolution is presented. Specifically, we include the Bak-Sneppen
evolution model, the Sneppen interface depinning model, the Zaitsev flux creep
model, invasion percolation, and several other depinning models into a unified
treatment encompassing a large class of far from equilibrium processes. The
formation of fractal structures, the appearance of noise, diffusion with
anomalous Hurst exponents, Levy flights, and punctuated equilibria can all be
related to the same underlying avalanche dynamics. This dynamics can be
represented as a fractal in spatial plus one temporal dimension. We develop
a scaling theory that relates many of the critical exponents in this broad
category of extremal models, representing different universality classes, to
two basic exponents characterizing the fractal attractor. The exact equations
and the derived set of scaling relations are consistent with numerical
simulations of the above mentioned models.Comment: 27 pages in revtex, no figures included. Figures or hard copy of the
manuscript supplied on reques
Search for the Flavor-Changing Neutral Current Decay with the HERA-B Detector
We report on a search for the flavor-changing neutral current decay using events recorded with a dimuon trigger in
interactions of 920 GeV protons with nuclei by the HERA-B experiment. We find
no evidence for such decays and set a 90% confidence level upper limit on the
branching fraction .Comment: 17 pages, 4 figures (of which 1 double), paper to be submitted to
Physics Letters
Measurement of the J/Psi Production Cross Section in 920 GeV/c Fixed-Target Proton-Nucleus Interactions
The mid-rapidity (dsigma_(pN)/dy at y=0) and total sigma_(pN) production
cross sections of J/Psi mesons are measured in proton-nucleus interactions.
Data collected by the HERA-B experiment in interactions of 920 GeV/c protons
with carbon, titanium and tungsten targets are used for this analysis. The
J/Psi mesons are reconstructed by their decay into lepton pairs. The total
production cross section obtained is sigma_(pN)(J/Psi) = 663 +- 74 +- 46
nb/nucleon. In addition, our result is compared with previous measurements
Shrinking a large dataset to identify variables associated with increased risk of Plasmodium falciparum infection in Western Kenya
Large datasets are often not amenable to analysis using traditional single-step approaches. Here, our general objective was to apply imputation techniques, principal component analysis (PCA), elastic net and generalized linear models to a large dataset in a systematic approach to extract the most meaningful predictors for a health outcome. We extracted predictors for Plasmodium falciparum infection, from a large covariate dataset while facing limited numbers of observations, using data from the People, Animals, and their Zoonoses (PAZ) project to demonstrate these techniques: data collected from 415 homesteads in western Kenya, contained over 1500 variables that describe the health, environment, and social factors of the humans, livestock, and the homesteads in which they reside. The wide, sparse dataset was simplified to 42 predictors of P. falciparum malaria infection and wealth rankings were produced for all homesteads. The 42 predictors make biological sense and are supported by previous studies. This systematic data-mining approach we used would make many large datasets more manageable and informative for decision-making processes and health policy prioritization
Search for composite and exotic fermions at LEP 2
A search for unstable heavy fermions with the DELPHI detector at LEP is
reported. Sequential and non-canonical leptons, as well as excited leptons and
quarks, are considered. The data analysed correspond to an integrated
luminosity of about 48 pb^{-1} at an e^+e^- centre-of-mass energy of 183 GeV
and about 20 pb^{-1} equally shared between the centre-of-mass energies of 172
GeV and 161 GeV. The search for pair-produced new leptons establishes 95%
confidence level mass limits in the region between 70 GeV/c^2 and 90 GeV/c^2,
depending on the channel. The search for singly produced excited leptons and
quarks establishes upper limits on the ratio of the coupling of the excited
fermio
Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment
This paper describes an analysis of the angular distribution of W->enu and
W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with
the ATLAS detector at the LHC in 2010, corresponding to an integrated
luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and
the missing transverse energy, the W decay angular distribution projected onto
the transverse plane is obtained and analysed in terms of helicity fractions
f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV
and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw
> 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour,
are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017
+/- 0.030, where the first uncertainties are statistical, and the second
include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables,
revised author list, matches European Journal of Physics C versio
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