Features of induced synchronization of a bistable oscillator with chaotic dynamics

The features of induced synchronization of a Chua oscillator with a nonlinear element admitting cubic approximation have been numerically simulated for a system where the autonomous operation admits regular or chaotic regimes determined by losses in the oscillatory circuit. The cases of deterministic synchronization (under the action of a harmonic external driving signal) and chaotic synchronization (chaotic control) have been considered. It is established that, outside the band of synchronous oscillations that corresponds to the deterministic synchronization, the external harmonic signal stimulates the transformation of regular oscillations into chaos with the motions switched between two attractors. In cases of chaotic synchronization, there is a residual “noise” in the form of differential chaotic oscillations, which grows with increasing non-identity of the driving and driven signals.     

Mutual chaotic synchronization of self-oscillating systems with inertance in a noise-like environment

The effect of external chaotic oscillations on systems of coupled generators with chaotic dynamics is studied. Coupled self-oscillating systems, in which partial generators are characterized either by Lorentz equations or by Rössler equations presented in the form of subsystems with inertance, are used as examples. The case of identical external chaotic oscillations affecting partial generators is considered. It is demonstrated that the synchronism of interacting oscillations is enhanced for both Lorentz andRössler coupled oscillations if the influences of noise-like oscillations on partial generators are identical.     

Chaotic oscillations in a system of coupled triggers

A circuit consisting of two triggers coupled by a capacitance is studied. The equations of motion are presented with a cubic approximation for the nonlinear terms. It is shown by numerical analysis that chaotic oscillations can be excited. A mechanism for the transition of the oscillations to chaos is described. Pis’ma Zh. Tekh. Fiz. 25, 1–6 (March 26, 1999)     

Preparation and characterization of ultra-thin cobalt silicide for VLSI applications

Ultra-thin cobalt silicide (CoSi₂) was formed from 10 nm cobalt film by solid phase reaction of Co and Si by use of rapid thermal annealing (RTA). The Ge⁺ ion implantation through Co film caused the interface mixing of the cobalt film with the silicon substrate and resulted in a homogeneous silicide layer. XRD was used to identify the silicide phases that were present in the film. The metallurgical analysis was performed by RBS. XRD and RBS investigations showed that final RTA temperature should not exceed 800°C for thin (< 50 nm) CoSi₂ formation.     

Health Council Report 'Radiofrequency electromagnetic fields (300 Hz-300 GHz). The Health Council of the Netherlands

The Health Council of the Netherlands in 1997 issued a report updating the guidelines for maximum acceptable exposure to radiofrequency electromagnetic fields formulated in 1975. The new recommendations are based on thermal effects for frequencies over 10 MHz. The committee considers the results of studies indicating non-thermal effects such as direct damage to DNA, not reliable enough to be used in setting exposure limits. Electromagnetic interference by electromagnetic fields generated by hand-held telephones may indirectly result in threats to health if vital medical equipment is affected. The committee advises people wearing an implanted pacemaker not to carry a portable telephone that is in stand-by mode in close proximity to the pacemaker; a minimum distance of 15 cm should be observed.     

Paracrine PDGF-B/PDGF-Rbeta signaling controls mesangial cell development in kidney glomeruli

Kidney glomerulus mesangial cells fail to develop in mice carrying targeted null mutations in the platelet-derived growth factor (PDGF)-B or PDGF-Rbeta genes. We have examined the pattern of expression of these genes and smooth muscle markers during kidney development, to address the possible mechanisms underlying the mutant phenotypes. In wild-type embryos, PDGF-B was expressed in vascular endothelial cells, particularly in capillary endothelial cells in the developing glomeruli, whereas PDGF-Rbeta was found in perivascular mesenchymal cells in the developing renal cortex. In the course of glomerular development, small groups of PDGF-Rbeta and desmin-expressing cells collected in the 'S'-shaped and early cup-shaped vesicles, and at later stages such cells were found in the glomerular mesangium. In PDGF-B or -Rbeta null embryos, some PDGF-Rbeta/desmin or desmin-positive cells, respectively, were seen in early cup-shaped vesicles, but fewer than in the wild type, and further development of the mesangium failed. In mouse chimeras composed of PDGF-Rbeta +/+ and -/- cells, the Rbeta-/- cells failed to populate the glomerular mesangium. Our results show that while the mesangial cell lineage is specified independently of PDGF-B/Rbeta, these molecules provide critical permissive signals in mesangial cell development. We propose a model in which mesangial cells originate from PDGF-Rbeta-positive progenitors surrounding the developing glomerular afferent and efferent arterioles, and are co-recruited in response to PDGF-B during angiogenic formation of the glomerular capillary tuft.     

Real-time detection of allele-specific polymerase chain reaction products by automated ultra-thin-layer agarose gel electrophoresis

Ultra-thin-layer agarose gel electrophoresis, a novel combination of agarose slab gel electrophoresis and capillary gel electrophoresis was introduced in conjunction with laser-induced fluorescence (LIF) scanning detection for the analysis of polymerase chain reaction (PCR) products. Allele-specific fragments, amplified from genomic DNA of patients with congenital adrenal hyperplasia (most often caused by mutations of 21-hydroxylase gene, CYP-21), were used as a model system to investigate the applicability, sensitivity and resolving power of the method. The allele-specific products were generated by PCR and separated by ultra-thin-layer agarose gel electrophoresis. The double-stranded DNA fragments were easily visualized in real-time via complexation during the separation process by the intercalator dye TO-PRO-3 which was part of the separation gel-buffer system. In this way, the migrating dsDNA-dye complexes were detected in real-time by a scanning LIF detection system with sub-nanogram sensitivity. The system employs a 632-nm solid-state laser and an avalanche photodiode detector scanning to the separation platform by means of a fiber bundle system. Automated ultra-thin-layer agarose gel electrophoresis with 'on the fly' TO-PRO-3 staining of dsDNA fragments and LIF detection system proved to be a very fast, high-throughput separation method for individual or multiplexed PCR products, with excellent sensitivity.     

Energy consumption during in-plane rolling

The energy consumed for in-plane rolling is analyzed theoretically. The total energy consumption in a working stand a _st is differentially considered in the form of the following terms: the energies consumed for plastic deformation a _d, friction in roll bearings a _f, and for rolling friction in work and backup rolls a _r. Analytical dependences of the specific energy consumption on the plastic-deformation and working-stand parameters are proposed. The results calculated by these dependences agree with the experimental data measured on driven roll spindles.     

Improvement of blast-furnace smelting at PAO Severstal’

In response to change in plant output and the hot-metal composition, unstable batch composition and characteristics, and increase in the recycled content, the maintenance of stable, economical, and highproductivity operation of the blast furnace shop at Cherepovets Metallurgical Works (PAO Severstal’) is of great importance. Particular attention focuses on increasing blast-furnace stability by improving the batch distribution within the furnace. The introduction of a blast-furnace technology with low slag yield (<250 kg/g of hot metal) is analyzed.