343 results match your criteria: "B.I. Stepanov Institute of Physics[Affiliation]"

The results are presented of a study of the photoluminescent (PL) properties of an undoped porous anodic alumina (PAA) and PAA doped with manganese ions. The PAA samples were prepared by anodization of aluminum. The effect of annealing conditions in vacuum on the PL spectra was studied for the first time and a comparative analysis was made with the spectra of the PAA annealed in air.

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The present work summarizes our experimental data on Surface-enhanced Raman scattering (SERS) of inorganic pigments. The effect of pigment type on Raman scattering enhancement was studied. The paper also describes the features of the SERS-active substrates used as well as the methods of sample preparation for SERS analysis of the pigments.

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In the context of using portions of a photosynthetic apparatus of green plants and photosynthesizing bacteria in bioinspired photovoltaic systems, we consider possible control of the chlorophyll excited state decay rate using nanoantennas in the form of a single metal and semiconductor nanoparticle. Since chlorophyll luminescence competes with electron delivery for chemical reactions chain and also to an external circuit, we examine possible excited state decay inhibition contrary to radiative rate enhancement. Both metal and semiconductor nanoparticles enable inhibition of radiative decay rate by one order of the magnitude as compared to that in vacuum, whereas a metal nanosphere cannot perform the overall decay inhibition since slowing down of radiative decay occurs only along with the similar growth of its nonradiative counterpart whereas a semiconductor nanoantenna is lossless.

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This Letter presents a search for the production of a long-lived neutral particle (Z_{d}) decaying within the ATLAS hadronic calorimeter, in association with a standard model (SM) Z boson produced via an intermediate scalar boson, where Z→ℓ^{+}ℓ^{-} (ℓ=e, μ). The data used were collected by the ATLAS detector during 2015 and 2016 pp collisions with a center-of-mass energy of sqrt[s]=13  TeV at the Large Hadron Collider and correspond to an integrated luminosity of 36.1±0.

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Treatment of plant seeds with electromagnetic fields or non-thermal plasmas aims to take advantage of plant functional plasticity towards stimulation of plant agricultural performance. In this study, the effects of pre-sowing seed treatment using 200 Pa vacuum (7 min), 5.28 MHz radio-frequency cold plasma (CP -2, 5, and 7 min) and electromagnetic field (EMF -5, 10, 15 min) on seed germination kinetics, content of phytohormones, morphometric parameters of seedlings and leaf proteome were assessed.

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Measuring Nonclassicality of Bosonic Field Quantum States via Operator Ordering Sensitivity.

Phys Rev Lett

March 2019

Univ. Lille, CNRS, UMR 8523 - PhLAM - Physique des Lasers Atomes et Molécules, F-59000 Lille, France.

We introduce a new distance-based measure for the nonclassicality of the states of a bosonic field, which outperforms the existing such measures in several ways. We define for that purpose the operator ordering sensitivity of the state which evaluates the sensitivity to operator ordering of the Renyi entropy of its quasiprobabilities and which measures the oscillations in its Wigner function. Through a sharp control on the operator ordering sensitivity of classical states we obtain a precise geometric image of their location in the density matrix space allowing us to introduce a distance-based measure of nonclassicality.

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A method is described for sensitive and selective detection of iodine by using a paper strip modified with silver triangular nanoplates (AgTNPs). It is based on the extraction of iodine from a solution into a flow of air via dynamic gas extraction and transferring it through a reactive paper modified with AgTNPs. The interaction of AgTNPs with iodine results in a color change from blue to white.

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Nitro derivatives of xanthione, 2,7-dinitro-9 H-xanthene-9-thione and 2,4,7-trinitro-9 H-xanthene-9-thione, have been first synthesized and their stationary and transient spectra have been measured. The stationary spectra show that the attachment of the nitro groups to the xanthione scaffold leads to strong quenching of S → S fluorescence and the decrease of the oscillator strength of the S ← S electronic transition. Analysis of the transient absorption spectra uncovers the ultrafast stimulated emission quenching from the second excited state, S, in the both derivatives.

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New insights into mechanism of direct UV photolysis of p-arsanilic acid.

Chemosphere

April 2019

V.V. Voevodsky Institute of Chemical Kinetics and Combustion, 3 Institutskaya str., 630090, Novosibirsk, Russian Federation; Novosibirsk State University, 2 Pirogova St., 630090, Novosibirsk, Russian Federation. Electronic address:

The mechanism of direct UV photolysis of p-arsanilic acid (p-ASA), a widely used veterinary drug, was revised by means of laser flash photolysis coupled with high resolution liquid chromatography - mass spectrometry (LC-MS). None of p-ASA triplet state or singlet oxygen was found to directly participate in the photodegradation of p-ASA as it was assumed in previous works. Here we demonstrate that the main primary photoprocess is a monophotonic ionization (ϕ = 0.

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A combination of the searches for pair-produced vectorlike partners of the top and bottom quarks in various decay channels (T→Zt/Wb/Ht, B→Zb/Wt/Hb) is performed using 36.1  fb^{-1} of pp collision data at sqrt[s]=13  TeV with the ATLAS detector at the Large Hadron Collider. The observed data are found to be in good agreement with the standard model background prediction in all individual searches.

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This Letter presents a measurement of γγ→μ^{+}μ^{-} production in Pb+Pb collisions recorded by the ATLAS detector at the Large Hadron Collider at sqrt[s_{NN}]=5.02  TeV with an integrated luminosity of 0.49  nb^{-1}.

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Updating the facile chemiluminescence oxygen-aftereffect method, most suitable for determining the rate constant (k ) of the peroxy-radical self-reaction (main chemiluminescence channel), pertained to considering the sensitivity of such a method toward a disturbing influence of the peroxy radicals of the initiator of the chain oxidation process. Such a disturbance may derive from the side chemiluminescent reaction, which involves peroxy radicals of both hydrocarbon and initiator. To examine the applicability and limitations of the chemiluminescence method under present scrutiny, cyclohexene was used as the model oxidizable hydrocarbon substrate.

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A search for resonant and nonresonant pair production of Higgs bosons in the bb[over ¯]τ^{+}τ^{-} final state is presented. The search uses 36.1  fb^{-1} of pp collision data with sqrt[s]=13  TeV recorded by the ATLAS experiment at the LHC in 2015 and 2016.

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Absorption and fluorescence spectra of a vinylogous series of reversely solvatochromic merocyanines based on benzimidazole and malononitrile have been studied in frozen ethanol solutions at 77 K. It is found that they possess negative thermochromism-in contrast to both positively solvatochromic merocyanines and negatively solvatochromic symmetrical ionic polymethines-and even stronger negative thermofluorochromism. It has been deduced from the spectral data that at low temperature their electronic structure becomes more dipolar, deviating substantially from the virtual ideal polymethine in both the ground and the excited states.

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A search for new heavy particles that decay into top-quark pairs is performed using data collected from proton-proton collisions at a centre-of-mass energy of 13  by the ATLAS detector at the Large Hadron Collider. The integrated luminosity of the data sample is 36.1 fb .

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This Letter presents a normalized differential cross-section measurement in a fiducial phase-space region where interference effects between top-quark pair production and associated production of a single top quark with a W boson and a b-quark are significant. Events with exactly two leptons (ee, μμ, or eμ) and two b-tagged jets that satisfy a multiparticle invariant mass requirement are selected from 36.1  fb^{-1} of proton-proton collision data taken at sqrt[s]=13  TeV with the ATLAS detector at the LHC in 2015 and 2016.

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Binary (Gd Si , GdSi) and ternary (Gd Si Ge ) compound nanoparticles (NPs) were prepared by laser irradiation of a mixture of colloidal solutions containing NPs of the relevant elements. It is assumed that the compound NPs are formed by heating, co-melting, and chemical interactions in the alloyed droplets. The blackbody-like radiation of the heated NPs was used for temperature control of the NP-preparation process.

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Jet substructure observables have significantly extended the search program for physics beyond the standard model at the Large Hadron Collider. The state-of-the-art tools have been motivated by theoretical calculations, but there has never been a direct comparison between data and calculations of jet substructure observables that are accurate beyond leading-logarithm approximation. Such observables are significant not only for probing the collinear regime of QCD that is largely unexplored at a hadron collider, but also for improving the understanding of jet substructure properties that are used in many studies at the Large Hadron Collider.

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A search for new phenomena in final states containing an or pair, jets, and large missing transverse momentum is presented. This analysis makes use of proton-proton collision data with an integrated luminosity of , collected during 2015 and 2016 at a centre-of-mass energy with the ATLAS detector at the Large Hadron Collider. The search targets the pair production of supersymmetric coloured particles (squarks or gluinos) and their decays into final states containing an or pair and the lightest neutralino ( ) via one of two next-to-lightest neutralino ( ) decay mechanisms: , where the boson decays leptonically leading to a peak in the dilepton invariant mass distribution around the boson mass; and with no intermediate resonance, yielding a kinematic endpoint in the dilepton invariant mass spectrum.

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Searches for dijet resonances with sub-TeV masses using the ATLAS detector at the Large Hadron Collider can be statistically limited by the bandwidth available to inclusive single-jet triggers, whose data-collection rates at low transverse momentum are much lower than the rate from standard model multijet production. This Letter describes a new search for dijet resonances where this limitation is overcome by recording only the event information calculated by the jet trigger algorithms, thereby allowing much higher event rates with reduced storage needs. The search targets low-mass dijet resonances in the range 450-1800 GeV.

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Nanoassemblies formed via self-assembly based on colloidal CdSe quantum dots (QDs) and porphyrin (H2P) dye molecules show Fluorescence Resonant Energy Transfer (FRET) and non-FRET quenching of QD photoluminescence (PL). We present a procedure to unravel and quantify these two relaxation pathways via dynamic and static PL quenching experiments. Accordingly, FRET amounts at maximum to 10% of the total quenching efficiency.

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The present work gives an overview of the developments in surface-enhanced Raman scattering (SERS) with metal-coated porous silicon used as an active substrate. We focused this review on the research referenced to SERS-active materials based on porous silicon, beginning from the patent application in 2002 and enclosing the studies of this year. Porous silicon and metal deposition technologies are discussed.

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A direct search for the standard model Higgs boson decaying to a pair of charm quarks is presented. Associated production of the Higgs and Z bosons, in the decay mode ZH→ℓ^{+}ℓ^{-}cc[over ¯] is studied. A data set with an integrated luminosity of 36.

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A search for the narrow structure, X(5568), reported by the D0 Collaboration in the decay sequence X→B_{s}^{0}π^{±}, B_{s}^{0}→J/ψϕ, is presented. The analysis is based on a data sample recorded with the ATLAS detector at the LHC corresponding to 4.9  fb^{-1} of pp collisions at 7 TeV and 19.

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