67 research outputs found

    Plasmonic and Thermooptical Properties of Spherical Metallic Nanoparticles for Their Thermoplasmonic and Photonic Applications

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    Investigations and use of nanoparticles (NPs) as photothermal (PT) agents in laser and optical nanotechnology are fast growing areas of research and applications. The potential benefits of NPs applications include possibility for thermal imaging and treatment of materials containing of NPs, applications of NPs for light-to-thermal energy conversion, in catalysis, laser nanomedicine, and chemistry. Efficiency of applications of metallic NPs for laser and optical nanotechnology depends on plasmonic and thermophysical properties of NPs, characteristics of radiation, and surroundingmedium. Herewe present the results of comparative analysis of NP properties (plasmonic, thermooptical, and others) allowing selecting their parameters for thermoplasmonic and photonic applications. Plasmonic and thermooptical properties of several metallic (aurum, silver, platinum, cobalt, zinc, nickel, titanium, cuprum, aluminum, molybdenum, vanadium, and palladium) NPs are theoretically investigated and analysis of them is carried out. Investigation of the influence of NPs parameters (type of metal, radii, optical indexes, density, and heat capacity of NP material), characteristics of radiation (wavelength and pulse duration), and ambient parameters on plasmonic and thermophysical properties of NPs has been carried out. It was established that maximum value of thermooptical parameter (maximum NP temperature) can be achieved with the use of absorption efficiency factor of NP smaller than its maximum valu

    Wavelets: mathematics and applications

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    The notion of wavelets is defined. It is briefly described {\it what} are wavelets, {\it how} to use them, {\it when} we do need them, {\it why} they are preferred and {\it where} they have been applied. Then one proceeds to the multiresolution analysis and fast wavelet transform as a standard procedure for dealing with discrete wavelets. It is shown which specific features of signals (functions) can be revealed by this analysis, but can not be found by other methods (e.g., by the Fourier expansion). Finally, some examples of practical application are given (in particular, to analysis of multiparticle production}. Rigorous proofs of mathematical statements are omitted, and the reader is referred to the corresponding literature.Comment: 16 pages, 5 figures, Latex, Phys. Atom. Nuc

    Modelling of the Total Electronic Content and magnetic field anomalies generated by the 2011 Tohoku-oki tsunami and associated acoustic-gravity waves,

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    International audienceIn this work, numerical simulations of the atmospheric and ionospheric anomalies are performed for the Tohoku-Oki tsunami (2011 March 11). The Tsunami-Atmosphere-Ionosphere (TAI) coupling mechanism via acoustic gravity waves (AGWs) is explored theoretically using the TAI-coupled model. For the modelled tsunami wave as an input, the coupled model simulates the wind, density and temperature disturbances or anomalies in the atmosphere and electron density/magnetic anomalies in the F region of the ionosphere. Also presented are the GPS-total electron content (TEC) and ground-based magnetometer measurements during the first hour of tsunami and good agreements are found between modelled and observed anomalies. At first, within 6 min from the tsunami origin, the simulated wind anomaly at 250 km altitude and TEC anomaly appear as the dipole-shaped disturbances around the epicentre, then as the concentric circular wave fronts radially moving away from the epicentre with the horizontal velocity ∼800 m s−1 after 12 min followed by the slow moving (horizontal velocity ∼250 m s−1) wave disturbance after 30 min. The detailed vertical-horizontal propagation characteristics suggest that the anomalies appear before and after 30 min are associated with the acoustic and gravity waves, respectively. Similar propagation characteristics are found from the GPS-TEC and magnetic measurements presented here and also reported from recent studies. The modelled magnetic anomaly in the F region ionosphere is found to have similar temporal variations with respect to the epicentre distance as that of the magnetic anomaly registered from the ground-based magnetometers. The high-frequency component ∼10 min of the simulated wind, TEC and magnetic anomalies in the F region develops within 6-7 min after the initiation of the tsunami, suggesting the importance of monitoring the high-frequency atmospheric/ionospheric anomalies for the early warning. These anomalies are found to maximize across the epicentre in the direction opposite to the tsunami propagation suggesting that the large atmospheric/ionospheric disturbances are excited in the region where tsunami does not travel

    Designing a model of interaction of economic resources in the quantization conditions of economic area

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    © 2015, Mediterranean Center of Social and Educational Research. All rights reserved. The article aims to develop a methodology for investigating cyclic recurrence of economic phenomena in the quantization conditions of the modern economy. The article highlights the quantization levels and the adaptive possibilities of stabilizing the economic processes and phenomena. The authors have developed a target model of interaction of economic resources in the quantization conditions, allowing to identify the type and stages of interaction at the current time. The results of the research have a wide range of applications in the development of specific manifestations of economic regularities by researchers, practicians working in the field of economics

    Pathogenetic aspects of cachexia

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    The relevance of cachexia syndrome is determined by its high prevalence in clinical practice. It accompanies the course of not only oncological diseases, but also the majority of chronic somatic pathologies, such as chronic heart failure, renal failure, diabetes mellitus, chronic obstructive pulmonary disease, acquired immunodeficiency syndrome, rheumatoid arthritis, Alzheimer’s disease and others. It is known that even a slight weight loss in patients can determine an unfavorable prognosis of the underlying disease and reduce the effectiveness of therapy, and sometimes it becomes the direct cause of death of the patient. Cachexia is a complex metabolic syndrome, which is based on a violation of the central regulation of metabolism. The dangerous combination of decreased appetite (anorexia) and increased metabolism is the result of an imbalance in energy exchange. Treatment of cachexia syndrome is ineffective and limited in means. Given the progressive and irreversible nature of this syndrome, early diagnosis and prevention of its development are the primary task of the doctor. The article describes the main pathogenetic aspects of the development of cachexia syndrome. They can be common in different diseases. The article discusses the difficulties of diagnosing cachexia syndrome, the possibilities and prospects of treatment

    Two-dimensional discrete wavelet analysis of multiparticle event topology in heavy ion collisions

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    The event-by-event analysis of multiparticle production in high energy hadron and nuclei collisions can be performed using the discrete wavelet transformation. The ring-like and jet-like structures in two-dimensional angular histograms are well extracted by wavelet analysis. For the first time the method is applied to the jet-like events with background simulated by event generators, which are developed to describe nucleus-nucleus collisions at LHC energies. The jet positions are located quite well by the discrete wavelet transformation of angular particle distribution even in presence of strong background.Comment: 6 pages, 6 figure

    Imaging and modeling the ionospheric airglow response over Hawaii to the tsunami generated by the Tohoku earthquake of 11 March 2011

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    Although only centimeters in amplitude over the open ocean, tsunamis can generate appreciable wave amplitudes in the upper atmosphere, including the naturally occurring chemiluminescent airglow layers, due to the exponential decrease in density with altitude. Here, we present the first observation of the airglow tsunami signature, resulting from the 11 March 2011 Tohoku earthquake off the eastern coast of Japan. These images are taken using a wide-angle camera system located at the top of the Haleakala Volcano on Maui, Hawaii. They are correlated with GPS measurements of the total electron content from Hawaii GPS stations and the Jason-1 satellite. We find waves propagating in the airglow layer from the direction of the earthquake epicenter with a velocity that matches that of the ocean tsunami. The first ionospheric signature precedes the modeled ocean tsunami generated by the main shock by approximately one hour. These results demonstrate the utility of monitoring the Earth's airglow layers for tsunami detection and early warning

    The state of erection in a patient with craniopharyngioma, panhypopituitarism and diencephalic obesity

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    The article presents a clinical case from the practice of a patient with craniopharyngioma. The man of reproductive age with diencephalic obesity (BMI 35 kg/m2), recurrent craniopharyngioma, a long history of endocrine disorders (panhypopituitarism, including secondary hypogonadism, with the corresponding sexual function disorders and the lack of sexual activity), with visual disorders and psychiatric symptoms in the early postoperative period after shunting surgery and reducing the volume of the craniopharyngioma cyst, erection conditions arose against the background of episodes of disorders of consciousness within the framework of sleep dissociation. After the operation (installation of the Ommaya system), the patient had a state of «spontaneous» erection lasting up to 30 minutes against the background of dream-oneiric states of impaired consciousness with erotic experiences. These states were observed for 3 nights, the patient remembered the experiences and events that occurred to him «in a dream», and could tell about them to others on the next morning. The identity of the patient remained intact, he was active in the department, ordered in behavior; memory for current events and new information was intact. These disorders in the patient did not require specialized treatment, regressed independently on the 6th day of the postoperative period

    Charged particle production in the Pb+Pb system at 158 GeV/c per nucleon

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    Charged particle multiplicities from high multiplicity central interactions of 158 GeV/nucleon Pb ions with Pb target nuclei have been measured in the central and far forward projectile spectator regions using emulsion chambers. Multiplicities are significantly lower than predicted by Monte Carlo simulations. We examine the shape of the pseudorapidity distribution and its dependence on centrality in detail.Comment: 17 pages text plus 12 figures in postscript 12/23/99 -- Add TeX version of sourc

    Nonlinear thermo-optical properties of two-layered spherical system of gold nanoparticle core and water vapor shell during initial stage of shell expansion

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    Nonlinear thermo-optical properties of two-layered spherical system of gold nanoparticle core and water vapor shell, created under laser heating of nanoparticle in water, were theoretically investigated. Vapor shell expansion leads to decreasing up to one to two orders of magnitude in comparison with initial values of scattering and extinction of the radiation with wavelengths 532 and 633 nm by system while shell radius is increased up to value of about two radii of nanoparticle. Subsequent increasing of shell radius more than two radii of nanoparticle leads to rise of scattering and extinction properties of system over initial values. The significant decrease of radiation scattering and extinction by system of nanoparticle-vapor shell can be used for experimental detection of the energy threshold of vapor shell formation and investigation of the first stages of its expansion
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