St. Petersburg State University of Telecommunications

About: St. Petersburg State University of Telecommunications is a education organization based out in Saint Petersburg, Russia. It is known for research contribution in the topics: Computer science & The Internet. The organization has 408 authors who have published 465 publications receiving 2160 citations.

The technique of field emission parameters research for nanostructured materials improvement

Abstract: A new technique was developed to record and in situ process the data on the evolution of multiwall carbon nanotubes polymer (MWCNT-polymer) nanocomposite field emitters. It includes multichannel acquisition system of current voltage characteristic (IVC), vacuum level, temperature and mass-spectrum data with computer on-line processing of these data based on the LabVIEW program. We obtained the time dependence of the field enhancement factor, the number of emission sites and kinetics of main volatile products during field emission process.

Paradigm of Controls Concept for Global Information Systems

Abstract: Information systems should provide high accuracy and reliability of the information provided. To build a global information resource with the properties of accessibility and reliability, as well as a wide range of data, it is necessary to determine effective control concepts. The subject of research is global information systems built on the basis of RDF repositories, which allow combining any ontology domains according to the principle of Linked Open Data. A conceptual scheme of entity matching is proposed in the development of RDF resources and the construction of SPARQL queries. The technique of increasing the speed of query processing is described.

Quantum statistical effects in multichannel wave-packet scattering of noninteracting identical particles

Abstract: For a number of non-interacting identical particles entering a multi-channel scatterer in various wave packet states, we construct a generating function for the probabilities of various scattering outcomes. This is used to evaluate the mean numbers of particles $\overline{n}_m$ scattered into a given ($m$-th) channel, single-channel statistics, and inter-channel correlations. We show that for initially uncorrelated particles, indistinguishability changes single channel statistics without altering the the value of $\overline{n}_m$. For uncorrelated bosons and fermions, bunching and anti-bunching behaviour can be detected in the extreme-case probabilities, to have all particles scattered into the same channel, or none of particles scattered into a channel, or channels. As an example, we consider a cavity with a single long-lived resonance accessible to the particles, which allows them to "pile up" inside the scatterer.

The influence of the polymer-stabilizer molecular weight on the spectral luminescence properties of composite sols and coatings containing PbS quantum dots

Abstract: The influence of the polyvinylpyrrolidone (PVP) molecular weight on the stability and spectral luminescence properties of sols of lead sulfide nanocrystals and the related composite coatings has been studied. It is shown that the spectral properties of PbS sols stabilized with low-molecular (PVP) and the related coatings are determined to a great extent by the formation of large particle aggregates in these materials and, accordingly, high level of light scattering. It is effective to use low-molecular PVP for preparing powder materials containing PbS quantum dots (QDs), because it allows one to perform fast powder precipitation and form small semiconductor particles. High-molecular PVP provides high aggregative and sedimentation stabilities of semiconductor nanocrystal sols. This polymer is effective for use in preparing stable QD sols and homogeneous coatings transparent in the visible spectral range.

Random variables associated with the Farey tree

Abstract: Tho paper investigates random variables associated with the limit distribution for the Farey tree rationals. Bibliography: 8 titles.