18 research outputs found
Attraction properties of the Ginzburg-Landau manifold
No full textWe consider solutions of weakly unstable PDE on an unbounded spatial domain. It has been shown earlier by the first author that the set of modulated solutions (called "Ginzburg-Landau manifold") is attracting. We seek to understand "how big" is the domain of attraction. Starting with general initial conditions of order " for the Fourier-transformed version of the given PDE we find that on the time-scale T " ; 2 (that is long in the terms of the original "physical" time t, but shorter than the natural time for the Ginzburg-Landau) the corresponding solutions evolve to the scaling of the clustered modes-distribution peaked at the integer multiples of the critical wave number, with the amplitudes sensitively dependent on such that for arbitrary close to zero after the time T " ; 2 solutions get on the Ginzburg-Landau manifold
MM-wave Patch Antenna with Embedded Photoconductive Elements for 1-bit Phase Shifting
No full textThe paper presents a development approach for mm-wave patch antenna with 1-bit (0/180 degrees) phase shifting. The proposed design employs a stacked patches structure, where the lower patch is excited symmetrically from an embedded single-pole double-throw switch. The switch is based on controllable photoconductive elements, where each element represents a high-resistivity silicon piece, which conductivity is modulated by a light source. Measured results demonstrate achievable (23-26) GHz -10-dB matching bandwidth and radiated field phase switching of (170-173)degrees. The approach can find its applications in beam steering antenna arrays and switchable monopulse antennas
Method for Phased Antenna Array Autofocusing with Amplitude-only Measurements
No full textThe paper presents an approach for fast antenna array autofocusing on a receiver position. The autofocusing procedure provides the maximum output power at receiver\u27s output. At the same time, the receiver is only capable of amplitude measurements. The crucial idea of the suggested method is employment of all phased antenna array\u27s radiators simultaneously, which makes the method suitable for arrays without amplitude control inside channels. We propose the representation of sought-for channel propagation vector as a linear combination of Hadamard matrix rows, whose complex coefficients are found from the suggested measurement procedure. The approach can be useful for different applications such as long-distance wireless power transmission, finding the channel state information matrix in communication systems and for antenna arrays calibration problems
Sub-THz U-Slot Coupled Stacked-Patch Radiating Elements for Dual-Polarized MIMO Array Antennas
No full textSeveral sub-THz (D-band, 136-148 GHz) dual-polarized array elements (unit cells, UCs) implemented in a multi-layer PCB technology are investigated in the infinite array environment. The elements are stacked-patch antennas with unbalanced aperture-coupled feeds (U-slots), having a slant 45 deg. polarization. We demonstrate that a baseline half-wavelength cavity-backed UC is capable of achieving ≤ 3.7 dB scan loss in the 60 deg. conical scan range and (132-149) GHz bandwidth. For the increased UC size, however, active polarization channel isolation drastically degrades and the element experiences scan blindness. To address this problem, a UC modification is introduced that suggests using a single-row mushroom-type electromagnetic band-gap structure along the UC sidewalls. Simulated results evidence the realized UC decoupling and elimination of the scan-blindness anomalies in the full visible scan range, with scan loss ≤ 4.2 dB in the 55 deg. conical scan range and (136-148) GHz bandwidth
The method of calculation and priority when crossing controlled intersection in the interval shifts permitting traffic light signal prohibiting
No full textThe article shows the need to establish the values of the deceleration value of the vehicle, which drivers must carry out speed reduction in the pace "without resorting to emergency braking." The definition of "emergency braking", not in the normative legal acts of the Russian Federation, and the deceleration of vehicles when you apply a driver braking temp without resorting to emergency." The example of calculation of the technical capabilities to make a stop in place, regulated by the Rules of the road, at the moment when the yellow traffic light when applying the emergency brake and brake on the pace, "without resorting to emergency.
Low-loss K-band Photoconductive Switches in SIW Technology
No full textA design approach for mmWave switches in substrate integrated waveguide (SIW) technology is demonstrated. The switch is based on a photoconductive element (PE) which represents a piece of an intrinsic silicon wafer with light modulated conductivity. Using both dielectric (high-resistivity) and conductive states of the PE, we can design a low-loss mmWave switching element. Owing to the light actuation, the control circuitry of the photoconductive switch (PS) is electrically separated from the high-frequency elements of the device. This solves the bottleneck of conventional mmWave switches based on PIN diodes, MOSFETs, MEMS, etc., which are bulky and lossy due to decoupling filters and matching elements of control and biasing circuits. The proposed approach is generic and can be applied to many mmWave applications within 10\ua0—\ua0100\ua0GHz such as 5G, WiGig, automotive radars, and others
Integrated W-band Photoconductive Switches in SIW Technology
No full textA novel approach for the design of mmWave substrate integrated waveguide (SIW) switches is presented. The switch is based on controllable photoconductive elements (PEs), whose conductivity is modulated by a light source. The PE is integrated on the top SIW metal plate and provides either a short-circuit or transmission operation regime, depending on the actuation conditions. Owing to the light actuation, the mmWave and DC control circuitry are naturally decoupled, which, in turn, makes the design low-loss and compact as compared to PIN diode and integrated circuit-based SIW switches implementations. We demonstrate two examples of SIW photoconductive switches (PSs) at W-band: single-pole single-throw (SPST) and single-pole double-throw (SPDT) PSs. Their operation principle, actuation, and parasitic radiation suppression are discussed. Measurements show the peak insertion loss of 0.9 and 2.2 dB, isolation better than 25 and 30 dB, and –10-dB impedance bandwidth of 21 and 15% for the SPST and SPDT PSs, respectively
Closed formula for options with discrete dividends and its derivatives
No full textWe present a closed pricing formula for European options under the BlackScholes model and formulas for its partial derivatives. The formulas are developed making use of Taylor series expansions and by expressing the spatial derivatives as expectations under special measures, as in Carr, together with an unusual change of measure technique that relies on the replacement of the initial condition. The closed formulas are attained for the case where no dividend payment policy is considered. Despite its small practical relevance, a digital dividend policy case is also considered which yields approximation formulas. The results are readily extensible to time dependent volatility models but no so for local-vol type models. For completeness, we reproduce the numerical results in Vellekoop and Nieuwenhuis using the formulas here obtained. The closed formulas presented here allow a fast calculation of prices or implied volatilities when compared with other valuation procedures that rely on numerical methods. --equity option,discrete dividend,hedging,analytic formula
EXTRACTS OF POPLARS BALSAMIC AS GROWTH REGULATORS OF SPRING WHEAT
No full textThe influence of different extracts obtained from leaves and buds of the poplars balsamic Populus balzamifera (water-soluble substances of the leaves, essential oil kidney and alcoholic extract of the kidneys), growing in the Krasnoyarsk territory, on the growth and development of spring wheat varieties Omskaya 36 in laboratory and field conditions is studied. Water-soluble substances leaves was isolated by the method of hot water extraction, alcoholic extract – ethyl alcohol under optimum conditions, the essential oil is by steam distillation. The obtained extracts from the vegetative parts of poplar researched generally accepted in chemistry of vegetable raw materials methods. Found that all prepared from extracts of poplar water emulsions affect the germination of seeds in laboratory conditions and on the initial growth (germination), and biological yield of spring wheat varieties Omskaya 36 in the field. The greatest positive impact on the productivity of wheat in the field had only emulsion based water-soluble substances leaves of the poplars balsamic with a concentration of 0,5 g/L. Increasing the drug concentration 10 times inhibited plant growth. Carbohydrates, amino acids and mineral components contained in the extract, presumably had a cumulative effect on seed germination and showed regulatory activity.</jats:p
COVID-19 Vaccine Education: Is It Effective?
No full textThe article presents experiment findings to verify the educational activities program in the field of COVID-19 vaccine prevention for students. The study was conducted at the Moscow State University of Psychology and Education, the analytical sample size is N = 780. Five aspects (as measuring scales) of attitudes towards vaccination against COVID-19 were identified: the benefits of vaccination against coronavirus for a person and society; denial of the coronavirus danger and hope for natural immunity; fear of the side effects of vaccination against coronavirus and distrust of vaccination safety information; confidence in the serious negative consequences of the coronavirus vaccine; disbelief in the proven effectiveness of Russian vaccines at the international level. A comparative analysis of the effectiveness of 4 strategies for influencing student's attitudes to vaccination against COVID-19 was carried out: lectures only (CG), lectures in combination with seminars / webinars in the traditional format (EG1), with discussions of real life cases related to vaccination and its effects (EG2), with holding student's debates (EG3). There are no gender differences between groups. There are differences in age, but the mean difference does not exceed 2 years. At the ascertaining stage, there are no differences on the scales; at the control stage, differences are revealed. On all 5 scales, positive and negative effects in the whole sample are almost equally likely. It was not possible to single out a fundamentally best strategy for educational influence. In general, the effectiveness of educational activities is somewhat greater when conducting lectures in combination with various kinds of seminars compared to lectures alone, but the effectiveness is low everywhere. Cohen's d standard effect sizes do not exceed 0,44. Slightly higher is efficiency when conducting lectures in combination with traditional seminars / webinars or case studies. The student's debates holding strategy did not meet expectations. A number of significant correlations were found between various aspects of attitudes towards vaccination with natural science literacy, logical thinking, verbal intelligence, the degree of fear of COVID-19, personal and situational anxiety. All correlations are weak, but their direction is as expected
