Generation of powerful microwave voltage oscillations in a diffused silicon diode

The mechanism of the generation of powerful microwave voltage oscillations in a diffused silicon diode is studied. A reverse current 2 kA in amplitude is passed through a 0.5-cm2 diode with a structure thickness of 320 μm, a p-n junction depth of 220 μm. At an average diode voltage of ∼300 V and a microwave pulse duration of ∼200 ns, the maximum voltage swing reaches 480 V. The oscillation frequency lies in the range 5 to 7 GHz; the power of the microwave pulse component is ∼300 kW. A theoretical consideration shows that voltage oscillations are caused by periodically repeating processes of breakdown and structure filling with plasma followed by its removal by the reverse current. The frequency and voltage swing are controlled by the current density and dopant-concentration gradient in the vicinity of the p-n junction. © 2013 Pleiades Publishing, Ltd

Picosecond Semiconductor Generator for Capacitive Sensors Calibration

The paper describes a semiconductor picosecond pulse generator that can be used to calibrate capacitive high voltage sensors of MV range. The generator is designed as a base unit, to which external pulse converters are connected. In the base unit, semiconductor devices – first a semiconductor opening switch (SOS) and then a semiconductor sharpener (SS) – generate an output pulse with a rise time of 220 ps and a subsequent flat-top of 2 ns in duration. The pulse amplitude is around 1 kV across 50 Ω load. An external diode sharpener generates a pulse with 120 ps rise time and 500-ps flat-top at the amplitude of 850 V. To switch the semiconductor sharpeners to the conducting state, the shock-ionization wave mode is used. Additional pulse converters make it possible to generate output pulses across 50 Ω load with the rise time of 70-150 ps, the pulse duration of 135-310 ps, and the amplitude of 130–480 V. The electrical diagram of the generator and waveforms of the output pulses are presented. An example of the calibration of capacitive sensors of a multi-gigawatt picosecond generator is also shown. © 2021 Institute of Physics Publishing. All rights reserved

The use of whole genome amplification for genomic evaluation of bovine embryos

The integration of high technologies into livestock production has been actively occurring in the last decade in the countries with a developed animal breeding. First of all, we are talking about reproductive technologies (IVF) and genomic technologies (general genomic evaluation of animal and genomic evaluation of breeding value). Combining reproductive and genomic technologies is a promising approach that allows receiving highquality breeding cattle in the shortest possible time. The basis of the proposed technology for accelerated reproduction of high-value breeding cattle is to obtain information about the genome of the embryo for genomic evaluation. The amount of genetic material that can be obtained for research is extremely limited, as it is necessary to preserve the viability of the embryo. The stage of the whole genome amplification was introduced to obtain a high quality of genetic material in a sufficient quantity. The main purpose of this work is to assess the possibility of using embryo biopsy specimens (bsp) for embryo genotyping using microarray chips and predicting the carrier status of lethal haplotypes at the embryo stage. We obtained 100 cattle embryos, of which 78 biopsy specimens were taken to analysis. For the biopsies obtained we performed the whole genome amplification. The quality and quantity of DNA for all the 78 samples after the whole genome amplification were satisfactory for further genotyping. The quality of the performed genotyping was satisfactory and allowed the assessment of lethal haplotype carriers (determining the sex of the animal and identification of the carrier status for sevenHolsteinlethal haplotypes). We tested 78 embryos. From the genotyping analysis, there was detected one carrier status for three lethal haplotypes, HH0 (Brachyspina), HH5, and HCD. The carrier status of HH0 and HH5 was confirmed by testing the casual mutation using PCR analysis. The carrier status for HCD has not been confirmed by casual mutation analysis. The situation in which an animal is an HCD carrier, but not the carrier of a casual mutation, can be explained. The putative ancestor of the haplotype is the bull HOCAN000000334489 WILLOWHOLME MARK ANTHONY (year of birth is 1975), but a casual mutation associated with this disease has arisen only in his descendant HOCAN000005457798 MAUGHLIN STORM (year of birth is 1991). The results obtained confirm the importance of testing the casual mutation in the animals that are carriers of lethal haplotypes according to the genotyping data

Fast high-power thyristors triggered in impact-ionization wave mode

GTO-like thyristors 5STH-2045H0002 (4.5 kV, 18 kA/µs) developed by ABB semiconductors are currently used at CERN in LHC Beam Dumping System (LBDS): high-power switches with high dI/dt capability and low turn-on delay time are required. Implementation of the impact-ionization triggering in GTO-like thyristor enhances its switching performance and gives new information about semiconductor physics. In this work thyristors of 5STH-2045H0002 type triggered in impact-ionization wave mode are investigated. A semiconductor opening switch (SOS) generator providing a dV/dt of several kV/ns was used as a source of triggering pulses. A thyristor switching time of approximately 200-300 ps was observed. Maximum discharge parameters were obtained for two series connected thyristors at a charging voltage of 10 kV, and a capacitor stored energy of 300 J: peak current of 43 kA, dI/dt of 120 kA/µs (limited by the discharge circuit), Full Width at Half Maximum (FWHM) of 1.5 µs. A single thyristor was tested in the repetitive mode at the charging voltage of 4.2 kV, and the stored energy of 18 J: peak current of 5.5 kA, dI/dt of 40 kA/µs, FWHM of 1.5 µs were obtained. No thyristor degradation was observed after more than one million pulses at a PRF up to 1 kHz in burst mode. Thyristor recovery time was 250 µs. The switching efficiency was up to 98% depending on dV/dt and stored energy. © 2019 CERN.Russian Foundation for Basic Research, RFBR: 17-08-00406, 18-08-01390Russian Academy of Sciences, RAS: 10.The work was supported by RFBR Grants Nos. 17-08-00406 and 18-08-01390, and by RAS Program Project No. 10. The study in part was carried out on the equipment of the Collective use centre at the Institute of Electrophysics, Ural Branch, Russian Academy of Sciences

On the electric activity of superfluid systems

The Keldysh's theory of superfluidity of rarefied electron-hole gas is generalized to a case of possible pair polarizability. It was shown that inhomogeneity of the system leads to dipole moment which is proportional to the density gradient. The dipole moment appears also near boundaries of the system. It was determined that quantized vortices in a magnetic field carry a real electric charge. In He II at H=10 T and helium rotation velocity $10^2$ s$^{-1}$ the charge density is about $10^4e$ cm$^{-3}$, where $e$ is the electron charge.Comment: 5 pages V. 2: replaced incorrect g valu

Generation of electromagnetic fields of extremely high intensity by coherent summation of Cherenkov superradiance pulses

We demonstrate both theoretically and experimentally the possibility of correlating the phase of a Cherenkov superradiance (SR) pulse to the sharp edge of a current pulse, when spontaneous emission of the electron bunch edge serves as the seed for SR processes. By division of the driving voltage pulse across several parallel channels equipped with independent cathodes we can synchronize several SR sources to arrange a two-dimensional array. In the experiments carried out, coherent summation of radiation from four independent 8-mm wavelength band SR generators with peak power 600 MW results in the interference maximum of the directional diagram with an intensity that is equivalent to radiation from a single source with a power of 10 GW

РОЛЬ ГЕНЕТИЧЕСКИХ ФАКТОРОВ В МЕХАНИЗМАХ РАЗВИТИЯ РЕМОДЕЛИРОВАНИЯ КОРОНАРНЫХ АРТЕРИЙ ПОСЛЕ ИМПЛАНТИРОВАНИЯ СТЕНТОВ

In the last 10 years the World has increased significantly the frequency of joint replacement in patients with coronary artery disease. Coronary angioplasty with stenting significantly improve the capacity and effectiveness of the treatment of coronary artery disease. However, an important factor limiting the effectiveness of endovascular treatment of restenosis remains the stented area.The article presents an overview of the most studied gene polymorphisms of hemostasis, inflammation system, the renin-angiotensin system, endothelial nitric oxide synthase, which can play a key role in the development of in-stent restenosis. Research in this area are significant and may help in understanding the mechanisms and risk stratification of restenosis after angioplasty.В последнее десятилетие в мире значительно выросла частота применения эндопротезирования при лечении лиц, страдающих ишемической болезнью сердца (ИБС). Коронарная ангиопластика со стентированием значительно расширила возможности и повысила эффективность лечения ИБС. Тем не менее важным фактором, ограничивающим эффективность эндоваскулярного лечения, остается развитие рестенозастентированного участка. В статье представлен обзор наиболее изученных полиморфизмов генов системы гемостаза, системы воспаления, ренин-ангиотензиновой системы, эндотелиальной синтазы оксида азота, которые могут играть ключевую роль в развитии рестеноза в стенте. Исследования в этом направлении являются существенными и могут помочь в понимании механизмов и стратификации риска развития рестеноза после ангиопластики

A comparison of sunlight exposure in men with prostate cancer and basal cell carcinoma

Ultraviolet radiation exposure increases basal cell carcinoma (BCC) risk, but may be protective against prostate cancer. We attempted to identify exposure patterns that confer reduced prostate cancer risk without increasing that of BCC. We used a questionnaire to assess exposure in 528 prostate cancer patients and 442 men with basal cell carcinoma, using 365 benign prostatic hypertrophy patients as controls. Skin type 1 (odds ratio (OR)=0.47, 95% CI=0.26–0.86), childhood sunburning (OR=0.38, 95% CI=0.26–0.57), occasional/frequent sunbathing (OR=0.21, 95% CI=0.14–0.31), lifetime weekday (OR=0.85, 95% CI=0.80–0.91) and weekend exposure (OR=0.79, 95% CI=0.73–0.86) were associated with reduced prostate cancer risk. Skin type 1 (OR=4.00, 95% CI=2.16–7.41), childhood sunburning (OR=1.91, 95% CI=1.36–2.68), regular foreign holidays (OR=6.91, 95% CI=5.00-9.55) and weekend (OR=1.17, 95% CI=1.08–1.27) but not weekday exposure were linked with increased BCC risk. Combinations of one or two parameters were associated with a progressive decrease in the ORs for prostate cancer risk (OR=0.54–0.25) with correspondingly increased BCC risk (OR=1.60–2.54). Our data do not define exposure patterns that reduce prostate cancer risk without increasing BCC risk