48 research outputs found

    Laser-Induced Bleaching of Carbon Nanomaterials Suspensions

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    We have studied the effect of nanosecond laser pulses on the optical properties of onion-like (OLC) and multi-wall carbon nanotubes (MWNTs) suspensions in N,N-dimethylformamide (DMF). The results demonstrate that both suspensions irreversibly bleach under high-intensity laser radiation. The bleaching is accompanied by losing optical limiting (OL) in suspensions. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3542

    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

    Application of Photothermal and Photoacoustic Spectroscopy for the Monitoring of Aqueous Dispersions of Carbon Nanomaterials

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    Photothermal  and  optoacoustic  spectroscopy  in their  state-of-the-art  techniques—multiwavelength, scanning  and  transient—are  used  for  complex investigation  and analysis  (chemical  analysis  and the  estimation  of  physicochemical  properties and size)  of  novel  carbon  materials—fullerenes  and nanodiamonds—and  their aqueous  dispersions  as promising biomedical nanosystems. The estimation of the cluster size and the possibilities to determine subnanogram  amounts  of  both nanodiamonds  and fullerenes  by  these  techniques  are  shown.  The comparison  of fullerene  solutions  in  various solvents,  toluene, N-methylpyrrolydone and  water, is made.  The  advantages  of  the  photothermal  and optoacoustic  techniques  over conventional spectroscopies  and  the  current  limitation  are discussed. The necessity to develop robust  models for  transient  and  imaging  photothermal  techniques is outlined

    Neutrino Masses in the Supersymmetric Standard Model with Right-Handed Neutrinos and Spontaneous R-Parity Violation

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    We propose an extension of the supersymmetric standard model with right-handed neutrinos and a singlet Higgs field, and study the neutrino masses in this model. The Majorana masses for the right-handed neutrinos are generated around the supersymmetry breaking scale through the vacuum expectation value of the singlet Higgs field. This model may induce spontaneous R-parity violation via the vacuum expectation value of the right-handed sneutrino. In the case, the effective theory is similar to a bilinear R-parity violating model. There are two sources for the neutrino masses: one is this bilinear R-parity breaking effect, and the other is the ordinary seesaw effect between left- and right-handed neutrinos. Combining these two effects, the hierarchical neutrino mass pattern arises even when the neutrino Yukawa matrices are not hierarchical. We acquire appropriate masses and mixings to explain both the solar and atmospheric neutrino oscillations.Comment: 22pages, RevTeX, 3 ps figures; a reference adde

    Status of a hybrid three-neutrino interpretation of neutrino data

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    We reanalyze the non-standard interaction (NSI) solutions to the solar neutrino problem in the light of the latest solar, atmospheric and reactor neutrino data. We show that such solutions, although preferred by the solar data and consistent with the oscillation description of the atmospheric neutrino data, are ruled out by the first results of the KamLAND reactor experiment, at more than 3_sigma.Comment: 19 pages, LaTeX file using Elsart, 2 tables and 4 figures included. This version updates the one published in Nucl.Phys.B629:479-490,2002 by including the new KamLAND dat

    Experimental evidence of two-band behavior of MgB2

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    The break-junction tunneling has been systematically investigated in MgB2. Two types of the break-junction contacts have been exploited on the same samples, which demonstrated tunnel contact like (SIS) and point contact like (SnS) behavior. Both of them have shown the existence of the two distinct energy gaps. We have observed also the peculiarities on the I(V)- characteristics related to Leggett's collective mode assisted tunneling. --> Corresponding author address: [email protected]: 14 pages, 6 figures, 1 table; corrected typos and fig

    Confusing non-standard neutrino interactions with oscillations at a neutrino factory

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    Most neutrino mass theories contain non-standard interactions (NSI) of neutrinos which can be either non-universal (NU) or flavor-changing (FC). We study the impact of such interactions on the determination of neutrino mixing parameters at a neutrino factory using the so-called ``golden channels'' \pnu{e}\to\pnu{\mu} for the measurement of \theta_{13}. We show that a certain combination of FC interactions in neutrino source and earth matter can give exactly the same signal as oscillations arising due to \theta_{13}. This implies that information about \theta_{13} can only be obtained if bounds on NSI are available. Taking into account the existing bounds on FC interactions, this leads to a drastic loss in sensitivity in \theta_{13}, at least two orders of magnitude. A near detector at a neutrino factory offers the possibility to obtain stringent bounds on some NSI parameters. Such near site detector constitutes an essential ingredient of a neutrino factory and a necessary step towards the determination of \theta_{13} and subsequent study of leptonic CP violation.Comment: 23 pages, 5 figures, improved version, accepted for publication in Phs. Rev. D, references adde

    Comparative study of the seismosensory system of two Amur grayling species in the zone of the sympatry

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    Background. This study was initiated for the morphological comparison of two species of recently described Amur graylings collected in the unique zone of their sympatry. This provided an infrequent opportunity for the estimation of the species-specific morphological diversification not determined by environmental conditions dissimilarity. This study aimed to compare the seismosensory systems of two species of Amur grayling, the lower Amur grayling, Thymallus tugarinae Knizhin, Antonov, Safronov et Weiss, 2007, and yellow-spotted grayling, Thymallus flavomaculatus Knizhin, Antonov et Weiss, 2006, collected in sympatric habitats with the inclusion of the published data on other northeast Asia grayling species. Materials and methods. The comparative study was based on samples of T. tugarinae and T. flavomaculatus specimens collected at species sympatric habitats in the middle stretch of the Anyuy River, one of the biggest tributaries of the Amur River. The lateral line system was stained, the topology was examined, and seismosensory system canal pores were counted. Differences in canal pore numbers between examined species were estimated with Wilcoxon signed-rank test. Also, cluster analysis was carried out. Results. Examined sympatric species were found to differ in the number of pores and secondary canaliculi topology but were similar to geographically distant grayling species. Conclusion. The results revealed sympatric morphological divergence of studied species and demonstrated parallelism of interspecies variability of examined features which are likely determined by conditions of species ecological optima. Comparative morphological analysis of the species and forms with questionable taxonomic status should be carried out using material that is collected in different parts of the habitation areal, paying special attention to the sympatry zones, if there are any such cohabitation regions, because the environmental factors have similar effects on all of the analysed species within such zones
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