462 research outputs found

    CARS diagnostics of near-critical fluid in small mesopores

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    Due to the high spacial resolution and theinterference nature, coherent anti-Stokes Ramanscattering (CARS) spectroscopy is well suited forthe diagnostics of composites based on transparentnanoporous hosts. In particular, the adsorption of afluid on the walls of nanopores and the formation ofa condensed phase in their volume leads to obvioustransformation of the CARS spectra. Recently wehave developed a model which describes thebehavior of molecular spectra at isothermalcompression in cylindrical nanopores. Calculationsbased on the model have shown a good agreementwith the experimental results for carbon dioxide innanoporous glass with pores of diameter of severalnanometers. Here we use the developed approach toinvestigate the phase behavior of carbon dioxide inglass nanopores at near-critical temperatures. It hasbeen experimentally shown that condensation innanopores occurs at relatively low pressures atsubcritical and even at supercritical temperatures.The analysis based on the developed model allowsto reveal some qualitative and quantitativecharacterizations of the shift of critical point

    Generation and Collection of Biological Nanoaerosols

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    The report describes new technologies in generation and collection of biological nanoaerosol (NA) developed in the laboratory of Nanostructures and Nanotechnologies, ITEB RAS. NA generator to be used for pulmonary delivery of antibiotics, anti-inflammatory and other drugs and vaccines employs a new atomization principle based on a gas-phase neutralization of electrospray-generated drug nanoclusters with small counter-ions produced by electrospraying of a volatile solvent like ethanol. It was demonstrated that a variety of biological substances including proteins can be atomized into NA of 20-100 nm in size, using this generator without affecting functional properties of the atomized substance. Several approaches have been developed to measure doses of inhaled NA including standard condensation particle counter, quartz resonator and filters from polyvinylpirrolidone nanofibers. It was demonstrated that water-soluble electrospun nanofilters may also be employed to capture pathogens and pathogen biomarkers for analysis of nosocomial infections in clinics wards, in collection of non-volatile biomarkers in the exhaled breath, in testing working places for NA pollution and in other applications. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3543

    Development of a Momentum Determined Electron Beam in the 1 -45 GeV Range

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    A beam line for electrons with energies in the range of 1 to 45 GeV, low contamination of hadrons and muons and high intensity up to 10^6 per accelerator spill at 27 GeV was setup at U70 accelerator in Protvino, Russia. A beam tagging system based on drift chambers with 160 micron resolution was able to measure relative electron beam momentum precisely. The resolution sigma_p p was 0.13% at 45 GeV where multiple scattering is negligible. This test beam setup provided the possibility to study properties of lead tungstate crystals (PbWO_4) for the BTeV experiment at Fermilab.Comment: 12 pages, 8 figures; work done by the BTeV Electromagnetic Calorimeter grou

    Comparison of Radiation Damage in Lead Tungstate Crystals under Pion and Gamma Irradiation

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    Studies of the radiation hardness of lead tungstate crystals produced by the Bogoroditsk Techno-Chemical Plant in Russia and the Shanghai Institute of Ceramics in China have been carried out at IHEP, Protvino. The crystals were irradiated by a 40-GeV pion beam. After full recovery, the same crystals were irradiated using a 137Cs^{137}Cs γ\gamma-ray source. The dose rate profiles along the crystal length were observed to be quite similar. We compare the effects of the two types of radiation on the crystals light output.Comment: 10 pages, 8 figures, Latex 2e, 28.04.04 - minor grammatical change

    Correlation of Beam Electron and LED Signal Losses under Irradiation and Long-term Recovery of Lead Tungstate Crystals

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    Radiation damage in lead tungstate crystals reduces their transparency. The calibration that relates the amount of light detected in such crystals to incident energy of photons or electrons is of paramount importance to maintaining the energy resolution the detection system. We report on tests of lead tungstate crystals, read out by photomultiplier tubes, exposed to irradiation by monoenergetic electron or pion beams. The beam electrons themselves were used to measure the scintillation light output, and a blue light emitting diode (LED) was used to track variations of crystals transparency. We report on the correlation of the LED measurement with radiation damage by the beams and also show that it can accurately monitor the crystals recovery from such damage.Comment: 9 pages, 6 figures, LaTeX2

    LED Monitoring System for the BTeV Lead Tungstate Crystal Calorimeter Prototype

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    We report on the performance of a monitoring system for a prototype calorimeter for the BTeV experiment that uses Lead Tungstate crystals coupled with photomultiplier tubes. The tests were carried out at the 70 GeV accelerator complex at Protvino, Russia.Comment: 12 pages, 8 figures, LaTeX2e, revised versio

    Design and performance of LED calibration system prototype for the lead tungstate crystal calorimeter

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    A highly stable monitoring system based on blue and red light emitting diodes coupled to a distribution network comprised of optical fibers has been developed for an electromagnetic calorimeter that uses lead tungstate crystals readout with photomultiplier tubes. We report of the system prototype design and on the results of laboratory tests. Stability better than 0.1% (r.m.s.) has been achieved during one week of prototype operation.Comment: 10 pages, 6 figures, LaTeX2

    Spin alignment of K(892)±K^*(892)^\pm mesons produced in neutron-carbon interactions

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    A new precise measurements of spin density matrix element ρ00\rho_{00} of K(892)±K^*(892)^{\pm} mesons produced inclusively in neutron-carbon interactions at \~60 GeV have been carried out in the EXCHARM experiment at the Serpukhov accelerator. The values of ρ00\rho_{00} obtained in the transversity frame are 0.424±0.011(stat)±0.018(sys)0.424\pm0.011(stat)\pm0.018(sys) for K(892)+K^*(892)^+ and 0.393±0.025(stat)±0.018(sys)0.393\pm0.025(stat)\pm0.018(sys) for K(892)K^*(892)^-. Significant PTP_T dependence of ρ00\rho_{00} has been observed in K(892)+K^*(892)^+ production.Comment: 8 pages, LaTeX, 3 eps figure

    Measurement of RudsR_{\text{uds}} and RR between 3.12 and 3.72 GeV at the KEDR detector

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    Using the KEDR detector at the VEPP-4M e+ee^+e^- collider, we have measured the values of RudsR_{\text{uds}} and RR at seven points of the center-of-mass energy between 3.12 and 3.72 GeV. The total achieved accuracy is about or better than 3.3%3.3\% at most of energy points with a systematic uncertainty of about 2.1%2.1\%. At the moment it is the most accurate measurement of R(s)R(s) in this energy range
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