Localization in periodically modulated speckle potentials

Disorder in a 1D quantum lattice induces Anderson localization of the eigenstates and drastically alters transport properties of the lattice. In the original Anderson model, the addition of a periodic driving increases, in a certain range of the driving's frequency and amplitude, localization length of the appearing Floquet eigenstates. We go beyond the uncorrelated disorder case and address the experimentally relevant situation when spatial correlations are present in the lattice potential. Their presence induces the creation of an effective mobility edge in the energy spectrum of the system. We find that a slow driving leads to resonant hybridization of the Floquet states, by increasing both the participation numbers and effective widths of the states in the strongly localized band and decreasing values of these characteristics for the states in the quasi-extended band. Strong driving homogenizes the bands, so that the Floquet states loose compactness and tend to be spatially smeared. In the basis of the stationary Hamiltonian, these states retain localization in terms of participation number but become de-localized and spectrum-wide in term of their effective widths. Signatures of thermalization are also observed.Comment: 6 pages, 3 figure

Effects of medium viscosity on kinetics of the enzymatic reaction catalyzed by bacterial RNase

Effects of medium viscosity on kinetic parameters of poly(U) hydrolysis catalyzed by RNase from Bac. intermedius 7P (binase) were studied in solutions of sucrose (4-50 wt. %) and glycerol (35-62 wt. %) in Tris-sodium acetate buffer (pH 7.5) at 25°C. The rate constant of reaction kcat was practically unchanged over a wide range of viscosities (1-15 cP for sucrose and 2.5-3 cP for glycerol). In glycerol solutions, kcat slightly increased with viscosity increase from 4 to 10 cP. Addition of NaCl to the buffer medium resulted in an inhibitory effect of Na+ on kcat, prevented by 50% sucrose or 60% glycerol. It is concluded that binase-catalyzed poly(U) cleavage occurs through a "tense"-substrate mechanism, similarly to reactions catalyzed by α-chymotrypsin, trypsin, and laccase

Исследование методов анализа видеоизображений с использованием сверточных нейронных сетей

Статья посвящена ознакомлению с основными принципами работы со сверточными нейронными сетями, в особенности в задачах связанных с идентификацией движущихся объектов. Также в работе представлена информация о работе сверточных слоев и их взаимодействии друг с другом. На данный момент, анализ большого количества видеоизображений приходится проводить вручную, что занимает большое время. Нейронные сети позволяют проводить анализ и идентификацию самостоятельно на основе алгоритмов заложенных в программу.The paper is devoted to the introduction of the basic principles of working with convolutional neural networks, especially in the tasks related to the identification of moving objects. The study also provides information about the operation of convolutional layers and their interaction with each other. At the moment, the analysis of a large number of video images has to be carried out manually, which takes a long time and is impossible without human intervention. Neural networks allow independent analysis and identification on the basis of algorithms embedded in the program

The formation of oxide layers on a titanium surface by irradiation with femtosecond laser pulses

By subjecting technical grade titanium to irradiation with femtosecond laser pulses with highenergy density, we create a microporous nanocrystalline oxide layer with a thickness of ∼50 μm on its surface. The structure and phase composition of the modified surface layers are studied using X-ray diffraction and high-resolution scanning and transmission electron microscopie

Formation of the oxide coating on the titanium surface by multipulse femtosecond laser irradiation

The effect of the femtosecond laser irradiation on the formation of oxide layers on the surface of a commercially pure titanium VT1-0 was studied. The methods of X-ray analysis, scanning electron and transmission electron microscopies were used to study the structural and phase state of oxide layers. As a result of the femtosecond laser irradiation, the porous multi-phase nanocrystalline oxide coating with a thickness of 50 µm is formed on the titanium surfac

Preparations of Bacillus pumilus secreted RNase: One enzyme or two?

© 2015, Pleiades Publishing, Ltd. Immunochemical analysis of the following purified preparations of Bacillus pumilus RNase (binase) was carried out: industrially manufactured enzyme (Institute of Organic Synthesis, Riga, Latvia) and the enzymes isolated from the culture liquid of the native B. pumilus producer and from the Escherichia coli BL21 recombinant strain bearing the pGEMGX1/ent/Bi plasmid. Electrophoresis of all three samples of purified binase revealed two protein fractions with ribonuclease activity possessing molecular masses of ∼12 and 25 kDa. The possible presence of binase II, a second secreted RNase, was ruled out. Both high- and low-molecular mass proteins interacted with binase-specific antibodies in the immunoblotting reaction, which indicated their antigenic identity. The difference in molecular mass between these proteins indicated the possible presence of two forms of binase in solution, a monomer and a dimer

Synthesis of pure hydroxyapatite by ion exchange reaction

An ion-exchange reaction for the synthesis of hydroxyapatite (HAP) in a constant alkaline medium using preliminary dry homogenization is proposed in this work. Sodium hydrogen phosphate Na2HPO4, calcium chloride CaCl2 and calcium hydroxide Ca(OH)2 were chosen as precursors. Studies carried out by methods of X-ray phase analysis, scanning electron and transmission microscopy showed that the material obtained is a singlephase hydroxyapatite powder with a Ca/P ratio close to 1.67. It was found that the particles of HAP powder obtained as a result of synthesis with subsequent washing have the shape of needles with a thickness of 10 to 40 nm and a length of 30 to 200 nm. Annealing of the powder at a temperature of 700 °C leads to agglomeration of particles, as well as to rounding of their shap

ANALYSIS OF CULTURAL EXCHANGE BETWEEN RUSSIAN AND FOREIGN STUDENTS

В статье показаны особенности культурного обмена между студентами разных стран. Представлены результаты интервью российских студентов, проходивших обучение за границей, а также иностранцев, получающих образование в России. Выделены культурные практики, преобладающие в молодежной среде, обозначено влияние образовательного процесса на восприятие студентами культуры других стран.The article shows the peculiarities of cultural exchange between students from diff erent countries. The results of interviews were conducted with Russian students who studied abroad, as well as with foreign students receiving education in Russia, are described. The cultural practices prevailing in the student environment are highlighted, and the infl uence of educational institutions on the perception of the country’s culture among students is also indicated