3,518 research outputs found
Effective attraction between oscillating electrons in a plasmoid via acoustic waves exchange
We consider the effective interaction between electrons due to the exchange
of virtual acoustic waves in a low temperature plasma. Electrons are supposed
to participate in rapid radial oscillations forming a spherically symmetric
plasma structure. We show that under certain conditions this effective
interaction can result in the attraction between oscillating electrons and can
be important for the dynamics of a plasmoid. Some possible applications of the
obtained results to the theory of natural long-lived plasma structures are also
discussed.Comment: 14 pages in LaTeX2e, two columns, 3 eps figures; minimal changes,
some typos are corrected; version published on-line in Proc. R. Soc.
Magnetic and spectral properties of multi-sublattice oxides SrY2O4:Er3+ and SrEr2O4
SrEr2O4 is a geometrically frustrated magnet which demonstrates rather
unusual properties at low temperatures including a coexistence of long- and
short-range magnetic order, characterized by two different propagation vectors.
In the present work, the effects of crystal fields (CF) in this compound
containing four magnetically inequivalent erbium sublattices are investigated
experimentally and theoretically. We combine the measurements of the CF levels
of the Er3+ ions made on a powder sample of SrEr2O4 using neutron spectroscopy
with site-selective optical and electron paramagnetic resonance measurements
performed on single crystal samples of the lightly Er-doped nonmagnetic
analogue, SrY2O4. Two sets of CF parameters corresponding to the Er3+ ions at
the crystallographically inequivalent lattice sites are derived which fit all
the available experimental data well, including the magnetization and dc
susceptibility data for both lightly doped and concentrated samples.Comment: 14 pages, 9 figure
Structure, optical, electrical and thermoelectric properties of solution-processed Li-doped NiO films grown by SILAR
The article presents a new facial synthesis of Li-doped NiO films (NiO:Li) via an easy and cost-effective method Successive Ionic Layer Adsorption and Reaction (SILAR) with the processing of the obtained NiO films in a
lithium-containing aqueous solution for their transformation after annealing into NiO:Li layers. Comparative analysis of crystal structure, optical, electrical and thermoelectric properties of the obtained NiO and NiO:Li 420-1050 nm thick films have reveiled a cubic rock-salt NiO structure, at that, NiO:Li samples are nanocrystalline single phased Li-NiO solid solutions. The fabricated NiO and NiO:Li films are p-type semiconductors with activation energy Ea = 0.1 eV and Ea = 0.25‒0.31 eV, respectively. The obtained in-plane Seebeck coefficients Z are in the range 0.20–0.33 mV/К. Notwithstanding the fact that the maximum values of the thermoelectric power factors P=2.2 μW/K2·m, are rather small, they were achieved if the hot end of the NiO:Li film was heated only to 115 °C. Thus, the produced in this work new low cost thermoelectric thin film material is suitable for a production of electrical energy for low-power devices due to absorption of low-potential heat
Estimate or the effectiveness of intelligent information system of early diagnosis and prognosis of cardiovascular disease
This article describes a new approach to the implementation of the training program of risk probability of coronary heart disease (CHD) remote evaluation. It describes an example of training sample formation based on the statistical analysis of medical data. The proposed solution will allow medical personnel to carry out the personification of cardiac services and first of all, preventive orientation. Also a method for assessing the effectiveness of the program of expert system "ARM-Cardiologist" on the results of ongoing clinical trials is providedyesБелгородский государственный университе
New exactly solvable systems with Fock symmetry
New superintegrable systems are presented which, like the Hydrogen atom,
possess a dynamical symmetry w.r.t. algebra o(4). One of them simulates a
neutral fermion with non-trivial dipole moment, interacting with the external
e.m. field. This system is presented in both non-relativistic and relativistic
formulations. Another recently discovered system (see arXiv:1208.2886v1) is
non-relativistic and includes the minimal and spin-orbit interaction with the
external electric field. It is shown that all the considered systems are shape
invariant. Applying this quality, these systems are integrated using the tools
of SUSY quantum mechanics.Comment: Section 6 and some new references are adde
Coherent Excitation of a Two-Level Atom driven by a far off-resonant Classical Field: Analytical Solutions
We present an analytical treatment of coherent excitation of a Two-Level Atom
driven by a far-off resonant classical field. A class of pulse envelope is
obtained for which this problem is exactly solvable. The solutions are given in
terms of Heun function which is a generalization of the Hypergeometric
function. The degeneracy of Heun to Hypergeometric equation can give all the
exactly solvable pulse shapes of Gauss Hypergeometric form, from the
generalized pulse shape obtained here. We discuss the application of the
results obtained to the generation of XUV.Comment: 9 Pages, 8 Figures. Accepted for Physical Review A as a regular
articl
Group classification of (1+1)-Dimensional Schr\"odinger Equations with Potentials and Power Nonlinearities
We perform the complete group classification in the class of nonlinear
Schr\"odinger equations of the form
where is an arbitrary
complex-valued potential depending on and is a real non-zero
constant. We construct all the possible inequivalent potentials for which these
equations have non-trivial Lie symmetries using a combination of algebraic and
compatibility methods. The proposed approach can be applied to solving group
classification problems for a number of important classes of differential
equations arising in mathematical physics.Comment: 10 page
Data-driven efficient score tests for deconvolution problems
We consider testing statistical hypotheses about densities of signals in
deconvolution models. A new approach to this problem is proposed. We
constructed score tests for the deconvolution with the known noise density and
efficient score tests for the case of unknown density. The tests are
incorporated with model selection rules to choose reasonable model dimensions
automatically by the data. Consistency of the tests is proved
Determination of EGFR gene somatic mutations in tissues and plasma of patients with advanced non-small cell lung cancer
The presence of activating mutations in the EGFR gene influences cell proliferation, angiogenesis, and increases metastatic ability; it has a significant impact on the choice of medical therapy of non-small cell lung cancer (NSCLC). The use of targeted therapy with tyrosine kinase inhibitors requires performance of appropriate genetic tests. The aim of this study was to design a real-time PCR-based diagnostic kit for fast and cheap of EGFR mutations testing in paraffin blocks and plasma, and kit validation using samples from patients with NSCLC, and also comparative estimation of diagnostic features of real-time PCR with wild type blocking and digital PCR for mutation testing in blood plasma. The study included 156 patients with various types of adenocarcinoma differentiation. It was designed a simple and efficient real-time PCR-based method of detecting L858R activating mutation and del19 deletion in the EGFR gene for DNA isolated from paraffin blocks. Kit for EGFR mutations was validated using 411 samples of paraffin blocks. The proposed system showed high efficiency for DNA testing from paraffin blocks: a concordance with results of testing with therascreen® EGFR RGQ PCR Kit ("Qiagen", Germany) was 100%. It has been shown the possibility of using this test system for the detection of mutations in plasma
Determination of EGFR gene somatic mutations in tissues and plasma of patients with non-small cell lung cancer
© 2017, Pleiades Publishing, Ltd. Activating mutations in the EGFR gene influence cell proliferation, angiogenesis, and increases metastatic ability of non-small cell lung cancer (NSCLC) cells; they have a significant impact on the choice of medical therapy of NSCLC. The use of targeted therapy with tyrosine kinase inhibitors requires performance of appropriate genetic tests in NSCLC patients. The aim of this study was to develop a real-time PCRbased diagnostic test-system for rapid and cost-effective analysis of EGFR mutations in paraffin blocks and plasma and to perform comparative estimation of diagnostic characteristics features of real-time wild type blocking PCR and digital PCR. The study included 156 patients with different degrees of lung adenocarcinoma differentiation. A simple and efficient real-time PCR-based method for detection of L858R activating mutation and del19 deletion in the EGFR gene in DNA isolated from paraffin blocks or blood has been developed. The test system for EGFR mutations has been validated using 411 samples of paraffin blocks. The proposed system demonstrated high efficiency for DNA testing from paraffin blocks: a concordance with results of testing by means a Therascreen® EGFR RGQ PCR Kit (Qiagen, Germany) was 100%. Applicability of this test system has been also demonstrated for detection of mutations in plasma
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