Superconducting Quantum Interference in Fractal Percolation Films. Problem of 1/f Noise

An oscillatory magnetic field dependence of the DC voltage is observed when a low-frequency current flows through superconducting Sn-Ge thin-film composites near the percolation threshold. The paper also studies the experimental realisations of temporal voltage fluctuations in these films. Both the structure of the voltage oscillations against the magnetic field and the time series of the electric "noise" possess a fractal pattern. With the help of the fractal analysis procedure, the fluctuations observed have been shown to be neither a noise with a large number of degrees of freedom, nor the realisations of a well defined dynamic system. On the contrary the model of voltage oscillations induced by the weak fluctuations of a magnetic field of arbitrary nature gives the most appropriate description of the phenomenon observed. The imaging function of such a transformation possesses a fractal nature, thus leading to power-law spectra of voltage fluctuations even for the simplest types of magnetic fluctuations including the monochromatic ones. Thus, the paper suggests a new universal mechanism of a "1/f noise" origin. It consists in a passive transformation of any natural fluctuations with a fractal-type transformation function.Comment: 17 pages, 13 eps-figures, Latex; title page and figures include

Exact analytical solution of a classical problem of the Josephson tunnel junction

We present the exact and complete analytical solution of the classical problem of the Josephson tunnel junction of arbitrary length W ∈ (0, ∞) in the presence of externally applied magnetic fields and transport currents. Contrary to a wide-spread belief, the exact analytical solution unambiguously proves the absence of any qualitative difference between the so-called «small» (W > 1). Another unexpected physical implication of the exact analytical solution is the existence (in the current-carrying state) of unquantized Josephson vortices carrying fractional flux and located near one of the junction's edges. We also refine on the mathematical definition of critical transport current

Observation of stochastic resonance in percolative Josephson media

Measurements of the electrical response of granular Sn-Ge thin films below the superconducting transition temperature are reported. Addition of an external noise to the magnetic field applied to the sample is found to increase the sample voltage response to a small externally applied ac signal. The gain coefficient for this signal as well as the signal-to-noise ratio displays clear maxima at particular noise levels. We interpret these observations as a stochastic resonance in the percolative Josephson media that occurs close to the percolation threshold

Use of low-frequency ultrasound in the combination treatment of the hypoplastic type of chronic endometritis

Objective. To evaluate the efficiency of treatment in patients with the hypoplastic type of chronic endometritis (CE) by uterine cavity irrigation with cavitation drug solutions exposed to low-frequency ultrasound (LFUS). Subjects and methods. 128 women diagnosed with the hypoplastic type of CE were examined. hypoplastic option. 64 patients of a study group (Group 1) received drug therapy and irrigation with a 0.05% cavitation chlorhexidine solution exposed to LFUS and with an immunomodulator solution (a total of 3 cycles). 64 patients of a comparison group (Group 2) had drug therapy only. The results were assessed by the time course of changes in the size of M-echo, endometrial histological examination before and after treatment, the occurrence of pregnancy and its outcomes. Results. The pretreatment endometrial thickness (M-echo data) was 5.8 ± 0.8 mm in Group 1 and 5.8 ± 0.5 mm in Group 2 (p = 0.899), the posttreatment one was 8.6 ± 0.3 and 6.4 ± 0.9 mm, respectively (p = 0.000). In the patients of the study group, the histological pattern in the endometrial biopsy specimens was observed to normalize in 11 (17.2 ± 0.05) and 64 (100%) patients after cycle treatments 2 and 3, respectively. In the comparison group, the endometrium after 4 and 6 months of treatment corresponded to the phase of the cycle in 2 (3.1% ± 0.02) and 18 (28.1% ± 0.06) women, respectively. In the first year after the end of therapy, pregnancy occurred substantially more commonly in Group 1 than in the comparison group (45.3 versus 28.15%). Pregnancy ended in childbirth in 89.7% of the patients in Group 1 and in 44.4% in Group 2; in these groups, there were miscarriages in 10.3 and 55.6%, respectively. Conclusion. Thus, LFUS used in patients with the hypoplastic type of CE promotes the adequate growth of the endometrium and the creation of favorable conditions for ovum implantation. © Bionika Media Ltd

Use of low-frequency ultrasound in the combination treatment of the hypoplastic type of chronic endometritis

Objective. To evaluate the efficiency of treatment in patients with the hypoplastic type of chronic endometritis (CE) by uterine cavity irrigation with cavitation drug solutions exposed to low-frequency ultrasound (LFUS). Subjects and methods. 128 women diagnosed with the hypoplastic type of CE were examined. hypoplastic option. 64 patients of a study group (Group 1) received drug therapy and irrigation with a 0.05% cavitation chlorhexidine solution exposed to LFUS and with an immunomodulator solution (a total of 3 cycles). 64 patients of a comparison group (Group 2) had drug therapy only. The results were assessed by the time course of changes in the size of M-echo, endometrial histological examination before and after treatment, the occurrence of pregnancy and its outcomes. Results. The pretreatment endometrial thickness (M-echo data) was 5.8 ± 0.8 mm in Group 1 and 5.8 ± 0.5 mm in Group 2 (p = 0.899), the posttreatment one was 8.6 ± 0.3 and 6.4 ± 0.9 mm, respectively (p = 0.000). In the patients of the study group, the histological pattern in the endometrial biopsy specimens was observed to normalize in 11 (17.2 ± 0.05) and 64 (100%) patients after cycle treatments 2 and 3, respectively. In the comparison group, the endometrium after 4 and 6 months of treatment corresponded to the phase of the cycle in 2 (3.1% ± 0.02) and 18 (28.1% ± 0.06) women, respectively. In the first year after the end of therapy, pregnancy occurred substantially more commonly in Group 1 than in the comparison group (45.3 versus 28.15%). Pregnancy ended in childbirth in 89.7% of the patients in Group 1 and in 44.4% in Group 2; in these groups, there were miscarriages in 10.3 and 55.6%, respectively. Conclusion. Thus, LFUS used in patients with the hypoplastic type of CE promotes the adequate growth of the endometrium and the creation of favorable conditions for ovum implantation. © Bionika Media Ltd