Magnetization and specific heat of the dimer system CuTe<Subscript>2</Subscript>O<Subscript>5</Subscript>

We report on magnetization and specific heat measurements on single-crystalline CuTe₂O₅. The experimental data are directly compared to theoretical results for two different spin structures, namely an alternating spin-chain and a two-dimensional (2D) coupled dimer model, obtained by Das et al. [Phys. Rev. B 77, 224437 (2008)]. While the analysis of the specific heat does not allow to distinguish between the two models, the magnetization data is in good agreement with the 2D coupled dimer model.     

Influence of the temperature modulation of an incident flux on the properties of films of cadmium selenotellurides synthesized under sharply nonequilibrium conditions

Results of structural and electrical investigations of the films of cadmium selenotellurides synthesized by evaporation and condensation in vacuum under sharply nonequilibrium conditions are presented. The modulating effect of a nonuniform thermal field on the vapor phase flux has been revealed. The possibility of controlling the stoichiometry of the film composition with the use of a thermal field applied on the path of the thermal phase from the evaporator to the substrate has been demonstrated. Curves of condensation and temperature dependences of the conductivity, Hall coefficient, and Hall mobility are presented.     

Modelling of different TIRM setups by the Discrete Sources Method

Total Internal Reflection Microscopy (TIRM) is an effective technique to measure weak interaction forces between colloidal particles in solution and a flat surface. In this paper the Discrete Sources Method has been applied to model different measuring schemes for TIRM to find the most appropriate one for the determination of the distance between a particle and the filmed surface. It has been found that the placing of a light collector beneath the prism gives a considerable advantage compared with a conventional TIRM design, where the collector is situated above the surface.     

Realization of matrix operations for the PRORAB computer

The article is devoted to the computer realization of well-known computational algorithms of linear algebra with sparse matrices. Formal programs of operations of the second kind (subschemes) over sparse matrices are derived, as well as sub-schemes realizing the normalized expansion of a matrix, the modified Danilewski method, the stepwise choice of the leading element in a process of Gaussian elimination type, the search for approximations to an eigenvalue by the method of traces, etc.Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 58, pp. 130–148, 1976.     

Methods for determining neurotransmitter metabolism markers for clinical diagnostics

Published data describing the current status and prospects for the development of clinical diagnostics of a number of neurodegenerative and neuroendocrine diseases associated with neurotransmitter balance disorders in a human body are generalized, systematized, and assessed in the review. Characteristics, advantages, and limitations of neuroimaging techniques and different diagnostic methods based on measuring concentrations of protein markers, catecholamines, and their metabolites are discussed. Prospects of the application of optical methods, such as fluorimetry and surface-enhanced Raman spectroscopy, to the development of sensor systems for the diagnosis of these diseases by the concentration of catecholamines and their metabolites in biological fluids are demonstrated.     

One-dimensional oxygen-ion conductors based on phosphorus-substituted bismuth molybdates: Preparation and characterization

Our study deals with the preparation, characterization, and electric conduction properties of complex oxides of formula Bi₁₃Mo_5–xP _x O_34.5–d, which manifest oxygen-ion conductivity at medium-range temperatures.     

Ultrafast x-ray scattering of xenon nanoparticles: imaging transient states of matter

Femtosecond x-ray laser flashes with power densities of up to 10(14) W/cm(2) at 13.7 nm wavelength were scattered by single xenon clusters in the gas phase. Similar to light scattering from atmospheric microparticles, the x-ray diffraction patterns carry information about the optical constants of the objects. However, the high flux of the x-ray laser induces severe transient changes of the electronic configuration, resulting in a tenfold increase of absorption in the developing nanoplasma. The modification in opaqueness can be correlated to strong atomic charging of the particle leading to excitation of Xe(4+). It is shown that single-shot single-particle scattering on femtosecond time scales yields insight into ultrafast processes in highly excited systems where conventional spectroscopy techniques are inherently blind.     

Spectral scattering properties of a nanohole in a noble-metal film in the evanescent waves area

The effect of enhanced optical transmission through subwavelength holes and their arrays is used for multiple practical applications especially in optical antennas and local biosensors design. This effect is usually considered under excitation of plane wave propagating at the normal direction to the screen surface. In this work the effect of extreme transmission through the hole in the evanescent wave's area is in focus. The discrete sources method has been applied to analyse the spectral characteristics of light scattered by a cylindrical nanohole in a noble-metal film on a prism surface. The influence of the wavelength, incident angle, film materials and hole's filling on the scattering characteristics has been investigated. A close correlation between the effect of extreme transmission and the surface plasmon resonances has been detected.