205 research outputs found
Scaling Behavior of Quasi-One-Dimensional Vortex Avalanches in Superconducting Films
Scaling behaviour of dynamically driven vortex avalanches in superconducting
YBaCuO films deposited on tilted crystalline
substrates has been observed using quantitative magneto-optical imaging. Two
films with different tilt angles are characterized by the probability
distributions of avalanche size in terms of the number of moving vortices. It
is found in both samples that these distributions follow power-laws over up to
three decades, and have exponents ranging between 1.0 and 1.4. The
distributions also show clear finite-size scaling, when the system size is
defined by the depth of the flux penetration front -- a signature of
self-organized criticality. A scaling relation between the avalanche size
exponent and the fractal dimension, previously derived theoretically from
conservation of the number of magnetic vortices in the stationary state and
shown in numerical simulations, is here shown to be satisfied also
experimentally.Comment: 7 pages, 5 figure
Application of machine vision technology for focused laser effect accuracy improvement in microelectronic structures research and semiconductor microprocessing
Machine vision is a field of artificial intelligence that deals with processing images and videos using special algorithms. This allows devices to analyze visual information. Machine vision helps with tasks such as pattern recognition, image segmentation, object detection, and tracking. In microscopy, machine vision plays an important role, particularly in laser scanning microscopy (LSM). Laser scanning microscopy, laser scribing, and laser correction of the topology of semiconductor crystals are important technological processes in the production, control and adjustment of semiconductor crystals both on debug samples and as part of a test batch on a wafer. Laser exposure allows not only mechanically separate crystals, but also carry out more delicate and minimally invasive actions, in particular, adjustments to the values of thin-film resistors or burning of bridges necessary to adjust the circuit and disable unused blocks of the crystal. The paper lists the main parameters of the positioning system as part of the laser scanning setup, their impact on the quality of scanning and exposure to focused radiation at control points. The principles of machine vision algorithms when working with the image of the scanned object and the results of testing in the task of automated laser burning of bridges on a semiconductor wafer are described. Since the number of bridges can reach tens of thousands, and positioning systems have significant errors, machine vision allows you to correct the area and accuracy of laser exposure at any stage of scanning, which significantly improves the quality and efficiency of the process
Nonlinear acousto-electric transport in a two-dimensional electron system
We study both theoretically and experimentally the nonlinear interaction
between an intense surface acoustic wave and a two-dimensional electron plasma
in semiconductor-piezocrystal hybrid structures. The experiments on hybrid
systems exhibit strongly nonlinear acousto-electric effects. The plasma turns
into moving electron stripes, the acousto-electric current reaches its maximum,
and the sound absorption strongly decreases. To describe the nonlinear
phenomena, we develop a coupled-amplitude method for a two-dimensional system
in the strongly nonlinear regime of interaction. At low electron densities the
absorption coefficient decreases with increasing sound intensity, whereas at
high electron density the absorption coefficient is not a monotonous function
of the sound intensity. High-harmonic generation coefficients as a function of
the sound intensity have a nontrivial behavior. Theory and experiment are found
to be in a good agreement.Comment: 27 pages, 6 figure
Hydrostatic and osmotic pressure study of the RNA hydration
The tertiary structure of nucleic acids results from an equilibrium between electrostatic interactions of phosphates, stacking interactions of bases, hydrogen bonds between polar atoms and water molecules. Water interactions with ribonucleic acid play a key role in its structure formation, stabilization and dynamics. We used high hydrostatic pressure and osmotic pressure to analyze changes in RNA hydration. We analyzed the lead catalyzed hydrolysis of tRNAPhe from S. cerevisiae as well as hydrolytic activity of leadzyme. Pb(II) induced hydrolysis of the single phosphodiester bond in tRNAPhe is accompanied by release of 98 water molecules, while other molecule, leadzyme releases 86
Some physico-chemical parameters that influence proteinase K resistance and the infectivity of PrP Sc after high pressure treatment
МАЗЬ ОФЛОМЕЛИД. КЛИНИКО-ЛАБОРАТОРНАЯ ЭФФЕКТИВНОСТЬ И ПЕРЕНОСИМОСТЬ У БОЛЬНЫХ С ИНФЕКЦИОННЫМИ ПРОЦЕССАМИ КОЖИ И МЯГКИХ ТКАНЕЙ
The paper presents the results of a multicenter postmarketing study of Oflomelid ointment versus levosin and levomecol ointments in 301 patients with different purulent diseases of the skin, soft tissues, and bones, diabetic foot syndrome, trophic ulcers of different etiologies, postoperative purulent wounds, chronic posttraumatic osteomyelitis, burns and frostbites, acute and chronic purulent diseases of the skin and soft tissues. Oflomelid ointment shows a high clinical and bacteriological efficacy in stages I and II wound process along with good analgesic activity for the topical treatment of purulent processes of different etiologies and sites. Objectivization of the findings is based on the results of qualitative and quantitative microbiological analyses, wound imprint cytology, and trends in the systemic and local clinical picture.В статье представлены результаты многоцентрового постмаркетингового сравнительного исследования мази Офломелид по сравнению с мазями левосин и левомеколь у 301 пациента с различными гнойными заболеваниями кожи, мягких тканей и костей, синдромом диабетической стопы, трофическими язвами различной этиологии, послеоперационными гнойными ранами, хроническим посттравматическим остеомиелитом, ожогами и отморожениями, острыми и хроническими гнойными заболеваниями кожи и мягких тканей. Показана высокая клиническая и бактериологическая эффективность мази Офломелид при I и II стадиях течения раневого процесса наряду с хорошим анальгезирующим действием для местного лечения гнойных процессов различной этиологии и локализации. Объективизация полученных данных основана на результатах качественных и количественных микро-биологических исследований, цитологии раневых отпечатков, динамики общей и местной клинической картины
Characterization of low-lying excited states of proteins by high-pressure NMR
Hydrostatic pressure alters the free energy of proteins by a few kJ mol-1, with the amount depending on their partial molar volumes. Because the folded ground state of a protein contains cavities, it is always a state of large partial molar volume. Therefore pressure always destabilises the ground state and increases the population of partially and completely unfolded states. This is a mild and reversible conformational change, which allows the study of excited states under thermodynamic equilibrium conditions. Many of the excited states studied in this way are functionally relevant; they also seem to be very similar to kinetic folding intermediates, thus suggesting that evolution has made use of the 'natural' dynamic energy landscape of the protein fold and sculpted it to optimise function. This includes features such as ligand binding, structural change during the catalytic cycle, and dynamic allostery
Temperature- and pressure-dependent stopped-flow kinetic studies of jack bean urease. Implications for the catalytic mechanism
Genes Required for Growth at High Hydrostatic Pressure in Escherichia coli K-12 Identified by Genome-Wide Screening
Despite the fact that much of the global microbial biosphere is believed to exist in high pressure environments, the effects of hydrostatic pressure on microbial physiology remain poorly understood. We use a genome-wide screening approach, combined with a novel high-throughput high-pressure cell culture method, to investigate the effects of hydrostatic pressure on microbial physiology in vivo. The Keio collection of single-gene deletion mutants in Escherichia coli K-12 was screened for growth at a range of pressures from 0.1 MPa to 60 MPa. This led to the identification of 6 genes, rodZ, holC, priA, dnaT, dedD and tatC, whose products were required for growth at 30 MPa and a further 3 genes, tolB, rffT and iscS, whose products were required for growth at 40 MPa. Our results support the view that the effects of pressure on cell physiology are pleiotropic, with DNA replication, cell division, the cytoskeleton and cell envelope physiology all being potential failure points for cell physiology during growth at elevated pressure
- …