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Regular version of the site
Of all publications in the section: 186
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Article
A N Varnavsky. Journal of Physics: Conference Series. 2019. Vol. 1210. No. 1. P. 1-8.

At the present, the actual task is using 3D printers for the manufacture of certain objects with a given level of price / quality ratio. In many cases, it is economically feasible to use a low cost 3D printer. Therefore, it is necessary to have models that predict and classify the printing quality of such printers. The work has involved the development and assembly of a low cost 3D printer. For this purpose, the creation of geometric models of the component parts and the printer itself was carried out, and engineering calculations and optimization of the received designs were performed. It has been developed a printer control system. An experiment was conducted to produce cubes with different printing parameters on such printer. Based on regression analysis, linear and logistic regressions were constructed. Linear regression will allow to assess the quality level of the result depending on the printing parameters, and the logistic regression will allow to classify and predict the probability of manufacturing objects with a given quality level. The influence of each of the print parameters on the quality and result of the classification was analyzed.

Added: Oct 8, 2019
Article
Ryazanova A.E., Amerikanov A.A., Lezhev E.V. Journal of Physics: Conference Series. 2019. Vol. 1163. No. 1. P. 1-7.

This work includes a review of MIPS architecture processor cores and a review of network topology consisting of routers. It was demonstrated by realization of 2 multiprocessor systems developed on the basis of mesh topology using modified schoolMIPS soft-processor cores, in which architecture additional blocks and instructions were added, and routers with XY routing. As a result, the obtained NoC performance is up to 1.87 Gbit/s (4 processor cores), and up to 1.54 Gbit/s (10 processor cores). The extended processor core schoolMIPS consumes 452 ALMs and 1692 bits of memory; NoC of 4 processor cores takes 2223 ALMs and 9136 bits of memory; NoC of 10 processor cores – 5696 ALMs and 22840 bits of memory. The obtained results suggest that there is a possibility of NoC development with the number of nodes up to 200 nodes on Stratix IV GX EP4SGX230 (DE4).

Added: Jun 24, 2019
Article
Lankin A., Orekhov M. Journal of Physics: Conference Series. 2018. Vol. 946. P. 1-7.

Recombination in liquid in diffusion regime is considered using molecular dynamics. A method to take into account change in interaction potential due to recombination act is suggested. Different processes that affect recombination rate are considered. It is found that ion cluster pair formation is important in addition to diffusion motion of ions. Results of the computation suggest that no other factors affect recombination at least within accuracy of 10%. It is shown with help of variation of recombination threshold radius and ion radius.

Added: Mar 22, 2018
Article
Skirnevskiy I., Pustovit A., Abdrashitova M.O. Journal of Physics: Conference Series. 2017. Vol. 803. No. 1. P. 1-7.

This article describes expediency of using a graphics processing unit (GPU) in big data processing in the context of digital images processing. It provides a short description of a parallel computing technology and its usage in different areas, definition of the image noise and a brief overview of some noise removal algorithms. It also describes some basic requirements that should be met by certain noise removal algorithm in the projection to computer tomography. It provides comparison of the performance with and without using GPU as well as with different percentage of using CPU and GPU.

Added: Oct 31, 2019
Article
Hushchyn M., Charpentier P., Ustyuzhanin A. Journal of Physics: Conference Series. 2015. Vol. 664.

This paper presents a system providing recommendations for optimizing the LHCb data storage. The LHCb data storage system is a hybrid system. All datasets are kept as archives on magnetic tapes. The most popular datasets are kept on disks. The recommendation system takes the dataset usage history and metadata (size, type, configuration etc.) to generate a recommendation report. In this article present how we use machine learning algorithms to predict future data popularity. Using these predictions it is possible to estimate which datasets should be removed from disk. We use regression algorithms and time series analysis to find the optimal number of replicas for datasets that are kept on disk. Based on the data popularity and the number of replicas optimization, the recommendation system minimizes a loss function to find the optimal data distribution. The loss function represents all requirements for data distribution in the data storage system. We demonstrate how the recommendation system helps to save disk space and to reduce waiting times for jobs using this data.

Added: Dec 21, 2015
Article
Natanzon S. M. Journal of Physics: Conference Series. 2016. Vol. 670. P. 1-6.

We describe all formal symmetric solutions of dispersionless 2D Toda hierarchy. This classi cation we use for solving of two classical problems: 1) The calculation of conformal mapping of an arbitrary simply connected domain to the standard disk; 2) Calculation of 2-Hurwitz numbers of genus 0.

Added: Feb 10, 2016
Article
Manita A., Manita L. Journal of Physics: Conference Series. 2018. Vol. 955. No. 012038. P. 1-6.

We propose new deterministic and stochastic models for synchronization of clocks in nodes of distributed networks. An external accurate time server is used to ensure convergence of the node clocks to the exact time. These systems have much in common with mathematical models of opinion formation in multiagent systems. There is a direct analogy between the time server/node clocks pair in asynchronous networks and the leader/follower pair in the context of social network models.

Added: May 19, 2018
Article
Timofeev A. Journal of Physics: Conference Series. 2019. Vol. 1147. No. 012100. P. 1-6.

The description of the properties of the plasma–dust system can be improved by using elements of thermodynamics. Divergence of the dusty particles trajectories allows us to estimate Krylov–Kolmogorov–Sinai entropy for a system of dust particles in plasma. In this way, we can verify if the behavior of the K-entropy of the dusty plasma subsystem in the partial equilibrium is close to the physical entropy. A picture of the divergence of trajectories for the dusty plasma model is obtained. The memory time of the model is estimated. The dependence of K-entropy on the number of dust particles and on the average kinetic energy of the dust particles are presented. The similarity of the behavior of the K-entropy parameter in the plasma–dust system and in the classical molecular-dynamic gas model is shown. The possibility of using this parameter for the description of dusty plasma is discussed.

Added: Oct 29, 2019
Article
Рыжиков А. С., Ustyuzhanin A. Journal of Physics: Conference Series. 2018. Vol. 1085. P. 1-6.

In the research, a new approach for finding rare events in high-energy physics was tested. As an example of physics channel the decay of \tau -> 3 \mu is taken that has been published on Kaggle within LHCb-supported challenge. The training sample consists of simulated signal and real background, so the challenge is to train classifier in such way that it picks up signal/background differences and doesn’t overfits to simulation-specific features. The approach suggested is based on cross-domain adaptation using neural networks with gradient reversal. The network architecture is a dense multi-branch structure. One branch is responsible for signal/background discrimination, the second branch helps to avoid overfitting on Monte-Carlo training dataset. The tests showed that this architecture is a robust a mechanism for choosing tradeoff between discrimination power and overfitting, moreover, it also improves the quality of the baseline prediction. Thus, this approach allowed us to train deep learning models without reducing the quality, which allow us to distinguish physical parameters, but do not allow us to distinguish simulated events from real ones. The third network branch helps to eliminate the correlation between classifier predictions and reconstructed mass of the decay, thereby making such approach highly viable for great variety of physics searches.

Added: Dec 11, 2017
Article
Norman G., Timofeev A. Journal of Physics: Conference Series. 2016. Vol. 774. No. 012170. P. 1-8.

The self-consistency and basic openness of dusty plasma, charge fluctuations, high dissipation and other features of dusty plasma system lead to the appearance of a number of unusual and unique properties of dusty plasma. “Anomalous” heating of dusty particles, anisotropy of temperatures and other features, parametric resonance, charge fluctuations and interaction potential are among these unique properties. Study is based on analytical approach and numerical simulation. Mechanisms of “anomalous” heating and energy transfer are proposed. Influence of charge fluctuations on the system properties is discussed. The self-consistent, many-particle, fluctuation and anisotropic interparticle interaction potential is studied for a significant range of gas temperature. These properties are interconnected and necessary for a full description of dusty plasmas physics.

Added: Feb 17, 2017
Article
Popel S I, Golub’ A. P., Zakharov A. V. et al. Journal of Physics: Conference Series. 2019. Vol. 1147. P. 1-11.

Dusty plasmas are shown to be formed in a surface layer over the illuminated part of Martian satellites Phobos and Deimos owing to photoelectric and electrostatic processes. The distribution functions of photoelectrons near surfaces of the satellites, altitude dependences of the density of dust particles, and their charges and sizes, as well as electric fields, have been determined within a physical-mathematical model for the self-consistent description of densities of photoelectrons and dust particles over the surface of the illuminated parts of Phobos and Deimos. In view of a weak gravitational field, dust particles rising over the surfaces of Phobos and Deimos are larger than those over the surface of the Moon. In this case, the role of adhesion, which is a significant process preventing the separation of dust particles from the lunar surface, is much smaller on Phobos and Deimos.

Added: Jan 21, 2019
Article
Popel S.I., Golub' A. P., Zelenyi L.M. et al. Journal of Physics: Conference Series. 2018. Vol. 946. P. 012142-1-012142-9.

A possibility of the formation in the lunar exosphere of dust cloud due to meteoroid impacts onto the lunar surface is studied. The main attention is paid to the high altitudes over the lunar surface including the range of the altitudes between 30 and 110 km where the measurements of dust were performed within the NASA LADEE mission. From the viewpoint of the formation of dust cloud at high altitudes over the Moon, the most important zone formed by the meteoroid impact is the zone of melting of substance. Only the droplets originated from this zone have the speeds between the first and second astronautical velocities (for the Moon). Correspondingly, only such droplets can perform finite movement around the Moon. The liquid droplets harden when rising over the lunar surface. Furthermore, they aquire electric charges due to the action, in particular, of the solar wind electrons and ions, as well as of the solar radiation. Thus dusty plasmas exist in the lunar exosphere with the characteristic number density $\lesssim 10^{-2}$~m$^{-3}$ of dust particles with the sizes from 300~nm to 1~${\rm\mu}$m which is in accordance with the results of measurements performed by LADEE.

Added: May 20, 2018
Article
Medvedev T. V., Medvedev V., Zhuzhoma E. V. Journal of Physics: Conference Series. 2018. Vol. 990. P. 1-9.

We suggest a new model of the fast nondissipative kinematic dynamo which describes the phenomenon of exponential growth of the magnetic eld caused by the motion of the conducting medium. This phenomenon is known to occur in the evolution of magnetic elds of astrophysical bodies. In the 1970s A.D. Sakharov and Ya.B. Zeldovich proposed a \rope" scheme of this process which in terms of the modern theory of dynamical systems can be described as Smale solenoid. The main disadvantage of this scheme is that it is non-conservative. Our model is a modi cation of the Sakharov-Zeldovich's model. We apply methods of the theory of dynamical systems to prove that it is free of this fault in the neighborhood of the nonwandering set.

Added: Apr 5, 2018
Article
Vlasenko V., Pervakov K., Pudalov V. et al. Journal of Physics: Conference Series. 2014. Vol. 507. No. 1. P. 022044-1-022044-4.

We report on successful fabrication of superconducting FeSe wire using hot gas extrusion (HGE) ex-situ PIT (powder in tube) method. Length of the obtained wire was about 60cm with cross-sectional superconducting core area nearly 2.5x 10^-3 cm^2. For the wire sample we observed superconducting transition temperature, T_onset =  11 K, about 1.2K lower compared to the preliminary prepared FeSe powder. Heat treatment in argon atmosphere at 350C resulted in transition width decrease from \Delta T(10% - 90%) = 1.75K in sample without heat treatment down to \Delta T = 0.9 K in annealed samples. Estimated derivative of the upper critical eld as a function of temperature of the sample annealed during 72h in argon atmosphere at 350C is dHc2/dT =2.9 T/K. Applying WHH theory to our data allows to defi ne Hc2(0K) = 0.69Tc x(dHc2/dT )=  19.8T. The untreated wire shows critical current density, Jc = 75 A/cm2 at T=4.0 K in zero fi eld. Increasing annealing time up to 72 hours at 350C in argon atmosphere gives rise to Jc increase of about 60% approaching 120 A/cm2 at T=4.0K and H=0T . Also Jc measurements were made in magnetic fields up to 9T. Our results show applicability of the HGE PIT method for fabrication of superconducting wires based on FeSe compound. Long-range heat treatment is necessary to improve superconducting properties of the samples.

Added: Mar 19, 2016
Article
Lankin A., Orekhov M. Journal of Physics: Conference Series. 2016. Vol. 774. P. 1-8.
Added: Apr 5, 2017
Article
Kuzin A., Kovalyuk V., Golikov A. et al. Journal of Physics: Conference Series. 2019. Vol. 1410. P. 1-5.

Here we experimentally studied dependence of a focusing grating coupler efficiency versus taper length and angle on silicon nitride platform. As a result, we obtained a dependence for the efficiency of a focusing grating coupler on the parameters of the taper length and angle.

Added: Dec 20, 2019
Article
Izvekova Y. N., Popel S. I. Journal of Physics: Conference Series. 2020. Vol. 1556. P. 012071.

We study dust vortices called dust devils and dynamics of dust in this structures. Dust devils are well formed relatively short-lived vortices that can appear over well heated surfaces like deserts and are clearly visible due to large amount of dust raised. Dust particles rotating in a flow bump and scrape each other and as a result particles obtain electric charges. Space separation of particles with opposite charges leads to generation of macroscopic electric field. We simulate dust dynamics with taking into account the electric field of the vortex.

Added: Jul 6, 2020
Article
Belavin V., Ustyuzhanin A. Journal of Physics: Conference Series. 2020. P. 1-7.

In this work, we propose an approach for electromagnetic shower generation on a track level. Currently, Monte Carlo simulation occupies 50-70\% of total computing resources that are used by physicists experiments worldwide. Thus, speedup of the simulation step allows to reduce simulation cost and accelerate synthetic experiments. In this paper, we suggest dividing the problem of shower generation into two separate issues: graph generation and tracks features generation. Both these problems can be efficiently solved with a cascade of deep autoregressive generative network and graph convolution network. The novelty of the proposed approach lies in the Neural networks application to the generation of the complex recursive physical process.

Added: Oct 31, 2019
Article
Smirnov K., Золотов Ф. И., Romanov N. et al. Journal of Physics: Conference Series. 2018. No. 1124. P. 1-6.

The research of ultrathin vanadium nitride (VN) films as a promising candidate for superconducting single-photon detectors (SSPD) is presented. The electron diffusivity measurements are performed for such devices. Devices that were fabricated out from 9.9 nm films had diffusivity coefficient of 0.41 cm2 /s and from 5.4 nm – 0.54 cm2 /s. Obtained values are similar to other typical SSPD materials. The diffusivity that increases along with decreasing of the film thickness is expected to allow fabrication of the devices with improved characteristics. Fabricated VN SSPDs showed prominent single-photon response in the range 0.9-1.55 µm

Added: Dec 27, 2018
Article
Krukov V. A., Suslov N., Markova V. et al. Journal of Physics: Conference Series. 2019. Vol. 1261. P. 1-6.

The energy sector of Russia is one of the most potent in the world - it is the second in extraction of oil and gas, the third for total output of fuel and energy resources. While exporting nearly 45% of its total production of energy resources, Russia produces more energy per capita than most other countries - 5 times higher the global average and 3 times higher than the average level for OECD countries. The energy sector of Siberia represents the crucial part of the country's energy sector. Over decades, the energy resources of the region massively contributed to the Russian federal budget and brought in a major part of hard currency from export trade. In the current conditions of existing geopolitical challenges and expected global demand for energy resources, it is much more of a priority for Russia not to raise the output of fuel and energy resources but to improve the overall quality and reliability of the whole energy supply system, increase the depth of mineral fuel, including solid fuel and waste recycling.

Added: Sep 12, 2019
Article
Timofeev A., Semyonov V. Journal of Physics: Conference Series. 2016. Vol. 774. No. 012171. P. 1-5.

Dust particles under certain conditions can acquire kinetic energy of the order of 10 eV and higher, far above the temperature of gas and temperatures of ions and electrons in the discharge. Such heating can be explained by the energy transfer between degrees of freedom of a dusty plasma system. One of the mechanisms of such energy transfer is based on parametric resonance. A model of dust particles system in gas discharge plasma including fluctuations of dust particles charge and features of near-electrode layer is presented. Molecular dynamics simulation of the dust particles system is performed. Conditions of the resonance occurrence are obtained for a wide range of parameters.

Added: Feb 17, 2017