Genetic Analyzer Nanofor 05 as a Measuring Instrument for DNA Sequencing

Measurement Techniques - Metrological support for DNA sequencing has been developed. Sequencing of a standard sample of a human mitochondrial DNA sequence was performed by the Sanger method on...     

Reconstruction of Coordinates of Scintillations in a Large-Size Cylindrical Detector with Radially Arranged Photomultipliers

An algorithm for calculating the scintillation coordinates developed for a large-size coordinate-sensitive detector is developed. The detector based on a liquid scintillator has nine radially arranged -174 photomultipliers. The results of simulation of the dependence of the coordinate resolution at the detector center on -quanta energy between 0.2 and 8 MeV are presented. The experimental data obtained with a collimated beam of -quanta from a ⁶⁰Co source, which irradiated the central part of the detector, were processed by using this algorithm. The -ray spectrum measured by the detector and the results of determining the scintillation coordinates for a -quanta beam are presented. The accuracy of coordinate measurements at the central region of the detector with this algorithm is 10 mm.     

Combined Ultramicrotomy and Atomic Force Microscopy Study of the Structure of a Bulk Heterojunction in Polymer Solar Cells

A method for visualization via atomic-force microscopy of the internal structure of photoactive layers of polymer solar cells using an ultramicrotome for photoactive layer cutting is proposed and applied. The method creates an opportunity to take advantage of atomic-force microscopy in structural investigations of the bulk of soft samples. Such advantages of atomic-force microscopy include a high contrast and the ability to measure various surface properties at nanometer resolution. Using the proposed method, samples of the photoactive layer of polymer solar cells based on a mixture of PTB7 polythiophene and PC₇₁BM fullerene derivatives are studied. The disclosed details of the bulk structure of this mixture allow us to draw additional conclusions about the effect of morphology on the efficiency of organic solar cells.     

Peculiarities of three-passage measurements in magnetic force microscopy

The method of three-passage measurements in magnetic force microscopy is described, which yields refined magnetic images of nano and microobjects, and eliminates the possible parasitic influence of long-range electrostatic forces while obtaining a magnetic image.     

Wave structure and flow amplitude-frequency characteristics in the turbine nozzle lattice in the presence of phase transition

This paper is devoted to the wave structure of a flow at its near- and supersonic velocities in a flat turbine cascade of profiles in the zone of phase transitions. The main task was investigation of the mechanics of interaction of the condensation jump with the adiabatic jumps of packing in a change of the initial condition of the flow. The obtained results are necessary for verification of the calculation models of the moisture-steam flow in the elements of lotic parts of the steam turbines. The experimental tests were made on a stand of the wet steam contour (WSC-2) in the Moscow Power Engineering Institute (MPEI, National Research University) at various initial states of steam in a wide range of Mach numbers. In the investigation of the wave structure, use was made of an instrument based on the Schlieren-method principle. The amplitude-frequency characteristics of the flow was found by measurement of static pressure pulsations by means of the piezo resistive sensors established on a bandage plate along the bevel cut of the cascade. It is shown that appearance of phase transitions in the bevel cut of the nozzle turbine cascade leads to a change in the wave structure of the flow. In case of condensation jump, the system of adiabatic jumps in the bevel cut of the cascade becomes nonstationary, and the amplitude-frequency characteristics of static pressure pulsations are restructured. In this, a change in the frequency pulsations of pressure and amplitude takes place. It is noted that, at near-sonic speeds of the flow and the state of saturation at the input, the low-frequency pulsations of static pressure appear that lead to periodic disappearance of the condensation jump and of the adiabatic jump. As a result, in this mode, the flow discharge variations take place.     

An experimental study of the development dynamics of the chaotic oscillation mode in a deterministic self-oscillatory microwave system

A possibility of experimentally obtaining an increased-output-power noise generator operating in the 3-cm wavelength range is considered. The noise generator was obtained by changing the self-excited oscillator, based on an avalanche-transit diode, to the chaotic generation mode by an external microwave signal action. Spectra of obtained chaotic generator oscillations with different parameters of both the generator and the external signal are presented. The statistical estimate of the quality of generated noise is given.