Suitability of variance shift keying for real conditions

This paper investigates the possibility of real-life using the brand new type of digital modulation, which implies the transmission of white Gaussian noise whose variance changes in time. That modulation has been entitled as variance shift keying. The signals obtained on its basis have a high level of transmission security, and they even cannot be detected by standard means of matched filtering. However, the paper suggests the decision on how to process these signals at the receiver site. It is proposed to use a specially developed optimal receiver, whose restoration quality appears to be better in comparison with the conventional cumulative receiver. The digital simulation of propagation in frequency selective media has shown the signal with variance shift keying is possible to be used in real conditions since its distribution of instantaneous amplitudes remains Gaussian. © 2018 Academic Mind.The work was supported by Act 211 Government of the Russian Federation, contract № 02.A03.21.0006. The research was executed by the grant of the Ministry of education and science of the Russian Federation (project № 8.2538.2017/4.6)

Thermo-chemical treatment of iron based composite electroplates

A scheme of renovating and hardening the parts with the use of composite electrochemical coatings is described. The powders of CrB 2 and Al 2O 3 serve as a dispersed phase in the electrodeposited coating from electrolytes containing FeCl 2 and FeSO 4. Chemical-and-thermal treatment (CTT) of parts was carried out at 210°C via sulfonitriding. Comparative tests of modified coatings and St45 for wear resistance in contact with 12KhN4A steel as a counterbody and for corrosion showed the improved characteristics after CTT

The effect of electrolyte composition on structure and properties of composite electrochemical coatings with copper matrix

A problem of wear resistance and hardness improvement is considered for copper coatings. Copper plating electrolyte is modified with addition of amine complexing agents and TiO 2 dispersed phase. Role of electrolyte composition and dispersed phase nature in structure forming and properties of composite electrochemical coatings Cu-TiO 2 is investigated. Diffraction layer-by-layer investigation of the composite coatings shows uniform distribution of dispersed phase in the deposit bulk and surface. The wear resistance of coatings is increased by 30-35%

Restoration of Static JPEG Images and RGB Video Frames by Means of Nonlinear Filtering in Conditions of Gaussian and Non-Gaussian Noise

The use of nonlinear Markov process filtering makes it possible to restore both video stream frames and static photos at the stage of preprocessing. The present paper reflects the results of research in comparison of these types image filtering quality by means of special algorithm when Gaussian or non-Gaussian noises acting. Examples of filter operation at different values of signal-to-noise ratio are presented. A comparative analysis has been performed, and the best filtered kind of noise has been defined. It has been shown the quality of developed algorithm is much better than quality of adaptive one for RGB signal filtering at the same a priori information about the signal. Also, an advantage over median filter takes a place when both fluctuation and pulse noise filtering. ©2017. American Geophysical Union. All Rights Reserved

Phase transition and anomalous electronic behavior in layered dichalcogenide CuS (covellite) probed by NQR

Nuclear quadrupole resonance (NQR) on copper nuclei has been applied for studies of the electronic properties of quasi-two-dimensional low-temperature superconductor CuS (covellite) in the temperature region between 1.47 and 290 K. Two NQR signals corresponding to two non-equivalent sites of copper in the structure, Cu(1) and Cu(2), has been found. The temperature dependences of copper quadrupole frequencies, line-widths and spin-lattice relaxation rates, which so far had never been investigated so precisely for this material, altogether demonstrate the structural phase transition near 55 K, which accompanies transformations of electronic spectrum not typical for simple metals. The analysis of NQR results and their comparison with literature data show that the valence of copper ions at both sites is intermediate in character between monovalent and divalent states with the dominant of the former. It has been found that there is a strong hybridization of Cu(1) and Cu(2) conduction bands at low temperatures, indicating that the charge delocalization between these ions takes place even in 2D regime. Based on our data, the occurrence of energy gap, charge fluctuations and charge-density waves, as well as the nature of phase transition in CuS are discussed. It is concluded that some physical properties of CuS are similar to those of high-temperature superconductors (HTSC) in normal state.Comment: to be publishe

Development and research of data transmission system using M-sequence

В исследовании синтезируется система передачи данных высокой помехозащищенности. Разработаны передающее и приемное устройства, реализующие метод расширения спектра, осуществляющие кодирование и декодирование передаваемого сообщения М-последовательностью. Схемы синтезированы в среде SysGen, эксперимент проведен на ПЛИС фирмы XILINX семейства Kintex7. Получение данных передатчиком осуществлялось с помощью стандарта «UART» со скоростью передачи 1,5 Мб/с. Эксперимент установил, что работоспособность системы ограничивается отношением мощности сигнала и помехи равной -14 дБ.A data transmission system with high noise immunity is synthesized. Transmitting and receiving devices, implementing the spread spectrum and carrying out transmitted message encoding and decoding by m‑sequence, are designed. Schemes are synthesized by using the SysGen software. The experiment is performed with Kintex7 PLD developed by XILINX. The system is based on the use of the standard «UART» with a rate of 1.5 Mbit/s. The experiment found that the system performance is limited by the signal-to-noise ratio equaled to -14 dB

The Road Towards the ILC: Higgs, Top/QCD, Loops

The International Linear e+e- Collider (ILC) could go into operation in the second half of the upcoming decade. Experimental analyses and theory calculations for the physics at the ILC are currently performed. We review recent progress, as presented at the LCWS06 in Bangalore, India, in the fields of Higgs boson physics and top/QCD. Also the area of loop calculations, necessary to achieve the required theory precision, is included.Comment: 7 pages, 1 figure. Plenary talk given at the LCWS06 March 2006, Bangalore, India. Top part slightly enlarged, references adde

Novel Azo-Dyes-Modified Isatin Derivatives: Synthesis, UV/VIS Spectroscopic, and Electrochemical Study

© 2016 Wiley-VHCA AG, ZürichA high-yield and simple synthesis of certain aminomethylisatins bearing dye fragments via the Mannich reaction of isatin with amino-containing azobenzenes was reported. It was found that the absence of electron-donating groups in azo-dye molecule prevents aminomethylation of isatin. The effect of the incorporation of an isatin moiety with an azobenzene dye in one molecule on its absorption and electrochemical behavior was studied using UV spectroscopy and cyclic voltammetry

Ion metal synthesis in viscous organic matter

The viscosity of the irradiated target as new parameter was introduced in ion implantation physics of organic matter. It was experimentally shown that using this parameter one enables to monitor the process of ion synthesis of thin granular impurity films. As an example, the results of high-dose implantation of Co+ and Ag+ ions in viscous epoxy experimenting stages of cure (polymerization) process are presented. It was established by TEM that the mean size, size distributions, form and crystalline structure of the synthesized metal particles depend on both ion beam parameters and viscosity of the epoxy target. The mechanisms of homogeneous nucleation and diffusive growth of metal particles in the low-viscosity epoxy in contrast to heterogeneous nucleation in solid polymers are discussed. The threshold implantation dose that is necessary for the formation of stable metal phase nucleation in a viscous medium was calculated by using the diffusion equation with a continuous Gauss-like source for the implanting impurity. It is shown that the specificity of epoxy polymerization influences the growth and crystalline structure of metal particles at intermediate stages of the epoxy cure process. The preliminary investigation of magnetic, optical and electrical properties of synthesized films is described as well