Multiple Andreev Reflections in Weak Links of Superfluid 3He-B

We calculate the current-pressure characteristics of a ballistic pinhole aperture between two volumes of B-phase superfluid 3He. The most important mechanism contributing to dissipative currents in weak links of this type is the process of multiple Andreev reflections. At low biases this process is significantly affected by relaxation due to inelastic quasiparticle-quasiparticle collisions. In the numerical calculations, suppression of the superfluid order parameter at surfaces is taken into account self-consistently. When this effect is neglected, the theory may be developed analytically like in the case of s-wave superconductors. A comparison with experimental results is presented.Comment: 12 pages, 9 figures, RevTeX

Proximity Effect Enhancement Induced by Roughness of SN Interface

Critical temperature reduction $\Delta T_c$ is considered for a thin film of a layered superconductor (S) with a rough surface covered by a thick layer of a normal metal (N). The roughness of the SN interface increases the penetration of electrons from the normal metal into the superconductor and leads to an enhancement of the proximity effect. The value of $\Delta T_c$ induced by the roughness of the SN interface can be much higher than $\Delta T_c$ for a film with a plain surface for an extremely anisotropic layered superconductor with the coherence lengths $\xi_a,\xi_b\gg\xi_c$.Comment: 2 page

Nonlinear resonance in a three-terminal carbon nanotube resonator

The RF-response of a three-terminal carbon nanotube resonator coupled to RF-transmission lines is studied by means of perturbation theory and direct numerical integration. We find three distinct oscillatory regimes, including one regime capable of exhibiting very large hysteresis loops in the frequency response. Considering a purely capacitive transduction, we derive a set of algebraic equations which can be used to find the output power (S-parameters) for a device connected to transmission lines with characteristic impedance $Z_0$.Comment: 16 pages, 8 figure

Hybrid Electro-Optic Capacitive Sensors for the Fault Diagnostic System of Hydrogenerator

This chapter presents one of the ways of solving a problem ensuring reliability reducing instability and emergence of the power generators during its work. Its way use hybrid electro-optic sensors (HFOS) with capacitive mechanical sensors at their structure of the fault diagnosis system of hydro generators for measurement parameters of machine mechanical defects as quality parameters of air gap, shaft out, core compression ratio and other. So this chapter also contains: principle of measurement of the sensor, which based on measuring the mutual displacement of the flatness of the generator structural element relative to coplanar sensor electrodes surface; the design principle for developing HFOS with capacitive mechanical sensor which combines the benefits of microelectronic and fiber-optic technology; determination response characteristics of the sensitive sensor (capacitive sensors with coplanar electrodes) of HFOS for monitoring air gap defects and power accumulators of core clamping system and system of control; analytical calculations and experimental studies of air gap HFOS with the AD7746 at its operating excitation frequency using; optimum geometry calculation of air gap sensor electrodes for bulb hydro generators type SGK 538/160-70М; analyze application the air gap HFOS for the control system in the bulb hydro generators type SGK 538/160-70М

Quasiparticle states of the Hubbard model near the Fermi level

The spectra of the t-U and t-t'-U Hubbard models are investigated in the one-loop approximation for different values of the electron filling. It is shown that the four-band structure which is inherent in the case of half-filling and low temperatures persists also for some excess or deficiency of electrons. Besides, with some departure from half-filling an additional narrow band of quasiparticle states arises near the Fermi level. The dispersion of the band, its bandwidth and the variation with filling are close to those of the spin-polaron band of the t-J model. For moderate doping spectral intensities in the new band and in one of the inner bands of the four-band structure decrease as the Fermi level is approached which leads to the appearance of a pseudogap in the spectrum.Comment: 8 pages, 7 figure

Electrophoretic separation and molecular size evaluation of hyaluronic acid

Hyaluronic acid (HA) is polysaccharide, which is consisting of remainders of glucuronic acid and n-acetylglucoseamine, connected by β 1.3’ – bonds. HA is used for treatment of bones, conjunctivitis, infertility, and also it is widely applied in cosmetology etc. HA has anti-adhesive, antiinflammatory, and lubricating properties, so could potentially be useful for spinal pain. HA administered epidurally had a therapeutic effect on the allodynia and hyperalgesia induced by chronic compression of the dorsal root ganglion