Radial oscillations of neutron stars in strong magnetic fields

The eigen frequencies of radial pulsations of neutron stars are calculated in a strong magnetic field. At low densities we use the magnetic BPS equation of state (EOS) similar to that obtained by Lai and Shapiro while at high densities the EOS obtained from the relativistic nuclear mean field theory is taken and extended to include strong magnetic field. It is found that magnetized neutron stars support higher maximum mass whereas the effect of magnetic field on radial stability for observed neutron star masses is minimal.     

Static and noise characteristics of nanocomposite gas sensors

Thin film gas sensors based on nanocomposite In₂O₃·Ga₂O₃·SnO₂ (70:20:10) have been manufactured by the high-frequency magnetron sputtering method. The technological cycle of sensor fabrication processes is described. Sensitivity of the prepared sensors at the temperature of working body 250°C and low-frequency noises within the 1–300 Hz range were investigated. The response of sensors to vapors of ethanol and acetone was investigated using resistive and noise methods. It is shown that the value of the sensitivity measured by the noise method exceeds the value of sensitivity measured by the resistive method. Sensors show appreciable sensitivity to the ethanol vapors already at working body temperature 150°C. Sensors can be used for the detection of low concentrations of ethanol vapors. The monotonous increase in the sensitivity of these sensors with increase in the ethanol and acetone vapors content allows applying nanosensors also for fast determination of gases concentration in air.     

Perfect Graphs, Partitionable Graphs and Cutsets

We prove a theorem about cutsets in partitionable graphs that generalizes earlier results on amalgams, 2-amalgams and homogeneous pairs. Received December 13, 1999 RID="*" ID="*" This work was supported in part by the Fields Institute for Research in Mathematical Sciences, Toronto, Canada, and by NSF grants DMI-0098427 and DMI-9802773 and ONR grant N00014-97-1-0196.     

Artificial ultrasound anisotropy of crystals in the range of X-ray frequencies

Phenomenon of artificial ultrasound anisotropy is revealed in crystals in the range of X-ray frequencies and an attempt is made to explain this effect theoretically for the case of the Bragg-Laue diffraction. It is established that an isotropic crystal becomes, under action of ultrasound, optically anisotropic like a uniaxial crystal with the optical axis along the direction of the external action; this axis is the symmetry axis and causes birefringence.     

Investigation of a fine structure of deuterium thermal desorption spectra from tungsten

The results of deuterium thermal desorption from tungsten after irradiation by 10 keV ions are discussed. A special heating procedure allows features of the fine structure of the thermal-desorption spectra maxima to be revealed.     

Erosion products of plasma facing materials formed under ITER-like transient load and deuterium retention in them

Erosion of the plasma-facing materials in particular evaporation of the materials in a fusion reactor under intense transient events is one of the problems of the ITER. The current experimental data are insufficient to predict the properties of the erosion products, a significant part of which will be formed during transient events (edge-localized modes (ELMs) and disruptions). The paper concerns the experimental investigation of the graphite and tungsten erosion products deposited under pulsed plasma load at the QSPA-T: heat load on the target was 2.6 MJ/m² with 0.5 ms pulse duration. The designed diagnostics for measuring the deposition rate made it possible to determine that the deposition of eroded material occurs during discharge, and the deposition rate is in the range (0.1–100) × 10¹⁹ at/(cm² s), which is much higher than that for stationary processes. It is found that the relative atomic concentrations D/C and D/(W + C) in the erosion products deposited during the pulse process are on the same level as for the stationary processes. An exposure of erosion products to photonic energy densities typical of those expected at mitigated disruptions in the ITER (pulse duration of 0.5–1 ms, integral energy density of radiation of 0.1–0.5 MJ/m2) significantly decreases the concentration of trapped deuterium.     

Lectin sensitized anisotropic silver nanoparticles for detection of some bacteria

A method of bacteria detection by sensitized anisotropic silver nanoparticles is presented. Anisotropic silver nanoparticles with two bands of surface plasmon resonance (SPR) are prepared and sensitized with potato lectin. These nanoparticles are able to detect three bacterial species: Escherichia coli, Bacillus subtilis and Staphylococcus aureus. The interaction of these bacteria with such nanoparticles induces drastic changes in optical spectra of nanoparticles that are correlated with bacteria titer. The maximal sensitivity is observed for S. aureus (up to 1.5 × 10⁴ mL⁻¹).