bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of Gingerols on Yeast Growth and Metabolism of the Fermentation Process
Authors: Li Zhixin , Ying Chen , He Chuan , Wei Min
Published: October 2020

In this paper, the effects of gingerol on yeast growth and metabolism of the fermentation process is investigated by measuring the minimum inhibitory concentration, growth curve, alcohol, residual sugar, pH, total acid, intracellular trehalose and glycerol in different stages of yeast fermentation. The results showed that the minimum inhibitory concentration (MIC) of gingerol was 6mg/mL. In the fermentation process, with the increase of the amount of gingerol, the yeast number, the alcohol of fermentation liquor and the Glucose-lowering rate were decreased, the fermentation was incomplete, pH was lower, total acidity was increased, and the content of trehalose and glycerol were increased. The inhibitory effect of gingerol amount on yeast was: 4 mg/mL>2 mg/mL>0.5 mg/mL>0 mg/mL (no gingerol was added). This showed that gingerol has an obvious inhibitory effect on the growth and fermentation of yeasts.
Kinematic Analysis and Trajectory Planning Simulation of Citrus Picking Manipulator
Authors: Xu Lijia , Liang Yuan , Kang Zhiliang
Published: October 2020

Trajectory planning is the premise of studying robot control. This study takes PUMA560 robotic arm as the research object and applies it to citrus picking. This research carried out kinematics analysis and simulation on its picking process, and then performed trajectory planning and workspace analysis. Firstly, the kinematics analysis and simulation of the picking robot arm were carried out in the forward and reverse direction, and the kinematics model was established by Denavit-Hartenberg method. Secondly, the trajectory planning of the robotic arm based on quintic polynomial interpolation is performed in the joint space, and the fitting curves of joint angular displacement, angular velocity and angular acceleration are plotted respectively. Finally, the working space of the picking manipulator is analysed and its working space diagram is drawn. The simulation results show that the trajectory planning and workspace drawing methods selected in this study are effective for the trajectory planning of citrus picking manipulator and provide theoretical support for the control research of citrus picking manipulator.
Research on the Control System of Winding Tension of Strip Stator
Authors: Zhao Kaijie , Zhao Liangliang , Zeng Sheng
Published: October 2020

In order to solve the problem of severe tension fluctuation in the winding process of strip stator, a tension control system is built with Micro-Controller Unit as controller, encoder as sensor and servo motor as actuator. Besides the employment of traditional PID feedback control, a feed-forward control link is introduced at the same time. The simulation results of PID control with and without feed-forward are compared. In addition, experiments under different working conditions are also carried out. Specifically, when the desired tension value is set at 500g along the 0.35mm enameled wire that being wound onto a strip stator at 900r/min, the tension overshoot and swing angle fluctuation are 0.88° and ±0.53° respectively. It is also found that, rather than the speed of the frame, it is the tension that significantly effects the control performance in the proposed system.
The Low-Frequency Acoustic Scattering Characteristics Study on Underwater Elastic Targets by the Coupled FEM-BEM Method
Authors: Xu Weilong , Shen Lijiao , Peng Weicai
Published: October 2020

A mathematical model about calculating acoustic scattering of elastic shell with air inside unbounded fluid was developed using a coupled finite element and boundary element technique. The coupling of elastic shell with air and shell with fluid was included in this model. To validate the scheme, the scattering characteristic of spherical shell with air submerged in water was calculated. Comparison of the numerical results with the corresponding analytical solutions shows that they are in good agreement in low frequency. On this basis, the low-frequency acoustic scattering characteristic of underwater elastic target was calculated with this method. The results showed the shell thickness and material have little effect on the target strength in the transverse direction, when the frequency is 100-300 Hz. In the omni-direction, the target strength of titanium alloy shell is higher than that of steel shell, and the larger the shell thickness, the greater the target strength. As the frequency is 200 Hz, the steel shell with a thickness of 28 mm has the phenomenon of acoustic resonance, resulting in a sharp increase in the target strength.
Affect of Elastic Displacement Limiter on Shock Response of Double-stage Vibration Isolation System
Authors: Gong Yufeng , Peng Weicai , Liu Zhizhong
Published: October 2020

With a certain shock load, the displacement of the equipment with double-stage vibration isolation mounting may exceed the deformation limits of isolators themselves. Therefore, elastic displacement limiters usually need to be used in order to limit the relatively large displacement. In this paper, the response of the double-stage vibration isolation system was studied by numerical method. Effects of stiffness and assembled clearance of elastic displacement limiter on shock response were discussed.
Dynamic Characteristics Analysis of Cracked Magnetic Rotor-Bearing System
Authors: Yang Yan , Zhang Lingyun , Zhang Yanxia
Published: October 2020

A dynamic model of the rotor system supported by active magnetic bearings at both sides is established, the fourth-order Runge-Kutta method is used to simulate. The periodic motion transition of the system and its evolution to chaotic motion are discussed from bifurcation diagrams and phase diagrams. It emphatically analyse the change of crack influencing factor and eccentricity on the system response and stability. The results show that the system presents period motion with appropriate parameter conditions. Large crack fatigue damage and value of eccentricity increases the amplitude and chaotic motion window in the low speed region, decrease the system stability. When the rotor crosses the critical speed range and reaches the high rotational speed region, the stable period-1 motion is dominant.
Multi-objective Optimization of Injection Process Parameters Based on EBFNN and NSGA-II
Authors: Lu Yuansan , Huang He
Published: October 2020

Taking the process parameters and quality index data obtained from the optimal Latin hypercube test of a front hood inner panel as sample data, this paper constructs an EBFNN approximate model by combining the NSGA-II multi-objective optimization algorithm to perform multi-objective optimization of injection molding process parameters, obtained Pareto solution set for volume shrinkage and warp during ejection. Comparing the Moldflow numerical simulation results of the four relatively optimized Pareto solutions, the optimal combination of process parameters is obtained. The optimized volume shrinkage and warp deformation reduced by 50.518% and 39.845% respectively, which verified the reliability and practicability of this method, and had certain practical reference significance for the optimization of injection molding process of other plastic parts.
Low Frequency Characteristics of a Two-Degree-of-Freedom Vibration System with Complex Rigid Constraints
Authors: Wang Shijun , Luo Guanwei
Published: October 2020

The dynamic model of a two-degree-of-freedom impact vibration system with complex rigid constraints under the action of periodic excitation force is established. Through the multi-objective and multi-parameter numerical simulation, the types and distribution areas of the periodic impact motions of the system in the (ω, δ)-parameter plane are obtained. The transition law of the fundamental impact motions of the system in the low frequency area is discussed, the generation mechanism of the tongue-shaped regions appearing in the transition process and the types of subharmonic motions in the tongue-shaped regions are analyzed.
Study on the Viscoelastic Behaviors of PMMA
Authors: Cheng Dong , Chen Tengfei , Cao Wei
Published: October 2020

The polymer rheology is essential for plastic manufacturing. In order to master the rheological characteristics of polymethyl methacrylate (PMMA) a viscoelastic model of PTT is employed to describe its rheological behaviors in 1-D channel flow. The corresponding governing equations are established based on isothermal impressible fluid. Then construct a numerical method to calculate the viscosity change with shear rates so as to explore the influences of the nonlinear parameter and relaxation time spectrum. The rheological experiments were carried out with three PMMA brands in a capillary rheometer to measure the viscosity at different shear rate. The experimental results show the Newtonian region appears within the scope [0, 2.1] for shear rate, and the constitutive equation can correct describe the rheological characteristics if the parameters are set properly.
Power Loss of Crystalline Solar Cell under Cyclic Loadings
Authors: Li Zhiqi
Published: October 2020

In application of building attached photovoltaic in China, the solar cells in the modules are mono-crystalline or polycrystalline cells. In some applications where the wind load is at higher level, a large deflection of the modules will occur. Due to the fluctuation of the wind load, the initial damages inside the cells will develop under this cyclic loading, as a result, the power loss of the solar cell can be observed due to the development of the fatigue damage. In this paper, the fatigue damage evolution of crystalline solar cell in module is investigated experimentally. The damage evolution with the cyclic number was obtained via the measurement of the power loss of the cell. The damage evolution equation was derived based on the continuum damage mechanics and the fatigue life of the cell was predicted.
Study on Wind-Induced Vibration of Tension String Shielding Ring for UHVDC Transmission Lines Based on Modal Test
Authors: Qi Yi , Zhang Zhao , Liu Shengchun , Si Jiajun
Published: October 2020

Under the action of natural wind, the shielding ring of tension string of UHVDC transmission line is prone to low frequency vibration, and the long-term vibration may lead to the fatigue damage of the shielding ring, threatening the safe operation of the line. In this paper, the modal test of the shielding ring of the tension string of UHVDC transmission line is carried out by using hammering method, and the natural frequencies and vibration mode shapes of the shielding ring are mastered. Combined with the analysis of the wind speed and wind direction in the engineering site, it is shown that the vortex induced vibration of the shielding ring is caused by the low-speed continuous stable wind along the line.
Newton Categories for a Solvable Element
Authors: Wan Fang
Published: October 2020

Let us suppose we are given an empty category π(
r
). We wish to extend the results of [9] to infinite, Eratosthenes triangles. We show that

W

<

h
¯

(

A

(
J
)

)

. In [9], the authors address the suijectivity of separable, nonnegative arrows under the additional assumption that V(X) is local. Recent developments in commutative algebra [25] have raised the question of whether every unique, partial, finitely abelian field is almost Cauchy, multiply Darboux and complete.
Stress Loading Analysis for Quayside Container Crane Draw Bar Based on VMD-Weibull Distribution
Authors: Hou Meihui , Hu Xiong , Dong Kai , Sun Zhiwei
Published: October 2020

The load distribution characteristics of quayside container crane (QCC) draw bar system is of great significance for fatigue analysis, life assessment and reliability calculation of metal structures. In order to describe the load distribution characteristics accurately, a method for extracting the characteristic parameters based on the VMD-Weibull distribution was proposed. Firstly, use the Wiener filtering feature of VMD to perform filtering processing. Then use the cubic spline interpolation envelope method to reconstruct the data, and performs Weibull distribution modeling on the reconstructed data to extract the scale parameters and shape parameters. Compared with the maximum entropy probability density curve, the stress loading is consistent with the Weibull distribution. At last, evaluate the draw bar and predict the development trend of the draw bar performance.
Analysis and Prediction of Air Quality based on LSTM Neural Network —— Take Beijing Temple of Heaven as an Example
Authors: Fang Hong , Zhang Lan
Published: October 2020

LSTM is an excellent variant model of RNN, which inherits the characteristics of most RNN models and solves the problem of gradient disappearance caused by a gradual reduction in the process of gradient backpropagation. LSTM is very suitable for processing data highly related to time series. This paper selects meteorological elements and air quality data of the temple of heaven in Beijing from 2016 to 2018, analyse the correlation between meteorological elements and air quality, selects index modeling, and designs an air quality prediction model based on LSTM neural network. It is concluded that the model has better accuracy and robustness. Finally, reasonable air pollution control measures are proposed to provide a scientific theoretical basis and new prediction methods for the prevention and control of air pollution.
Structural Optimization Design of H-type Piezoelectric Actuator Based on APDL
Authors: Rui Suyuan , Wang Xinjie
Published: October 2020

Aiming at the problem of low efficiency in optimizing the H-type piezoelectric actuator with the “trial method”, this article uses a program written in the APDL (ANSYS Parametric Design Language) to optimize the structure of the piezoelectric actuator. First, a parametric finite element model is established based on the initial data values of the mover structure. Modal analysis and sensitivity analysis are performed to determine the design variables. Then, the objective function is determined based on the frequency consistency of the two-phase working modes. Finally, based on the optimization tool proposed in this paper, the structure of the H-type piezoelectric actuator is optimized. The optimization results show that the optimization program based on APDL can achieve the optimal design requirements of the H-type piezoelectric actuator and shorten the time required for structural optimization design.
Nonlinear Numerical Simulation of Service Behaviour of Regenerative Burner under Multiple Thermal Shocks
Authors: Jiang Fanzhi , Kong Jianyi , Ouyang Degang
Published: October 2020

In order to explore the service behaviour of regenerative burner parts, the burner refractory was studied experimentally and thus a series of temperature-related material performance parameters were obtained. A method for calculating the Young’s modulus of materials between two thermal shocks was proposed by combining the law of Young’s modulus varying with temperature and that of residual Young’s modulus varying with the quantity of thermal shocks. The service process of the burner under the condition of multiple thermal shocks was nonlinearly simulated by using the obtained parameters. The results show that the thermal load of regenerative burner in stable service is about 0.55 MPa, that is much less than the previous result without considering the material nonlinear characteristics, 37Mpa.
Simulation Analysis of Cavity Shape of Compound Pendulum Jaw Crusher
Authors: Zhong Xiaoqin , Niu Xiaojian , Ji Qiqiang , Shen Xiuguo
Published: October 2020

Taking the working device of PE1500 × 1800compound pendulum jaw crusher as the research object, 3D model of working devices of four different cavity shape compound pendulum jaw crushers is carried out by using SolidWorks, and then the kinematic simulation software ADAMS is imported to carry out the kinematic simulation, and the horizontal and vertical displacement change curves of four characteristic points of the lower part of the crushing cavity are obtained. According to the simulation results, the relative production capacity and the block-up coefficient of each broken layer of the jaw crusher are calculated under the same spindle speed and different cavity shape. The results show that the block-up coefficient of the crusher with curved crushing chamber is smaller and its relative production capacity is larger.
Progress and Key Technical Control Points of Side Slip-form Construction Technology
Authors: Liu Ying , Wang Xinpeng
Published: October 2020

Slip-form pavement of road surface construction is an efficient mechanical construction method, compared to the traditional construction method of erection of template for cast in situs or backcourt prefabrication while hoisting in the front court, slip-form construction technology dispenses with the prefabrication site and a lot of prefabrication dies, meanwhile, it reduces the process of handling and lifting, and can improve the flatness of the structure to obtain beautiful line type and unified color. Moreover, it can achieve “low-carbon” construction by reducing the energy consumption. In this paper, introduction was given for key technology of the construction technology and the current foreign development situation, to provide a reference for engineering technicians.
Research on Application of Wheels with External Track Technology under Soft Road Condition
Authors: Hou Youshan , Wang Chao , Cai Wenbin
Published: October 2020

Wheeled vehicles usually adopt external track when passing through soft road conditions. Taking the large wheelbase four-wheel vehicle as the example, based on recurdyn, the dynamic simulation analysis of two driving modes of wheeled vehicles and wheel with external track was completed, focusing on the comparative analysis of ground specific pressure, hook traction, wheel sinkage and other aspects. The results show that the vehicle passability under the soft condition is improved after the wheels are attached to the track, the vehicle’s theoretical grounding is 86.7% less than the reduction, and the hook traction is nearly 10 times higher. However, for the large wheelbase structure, the track between the two wheels needs to improve the passability by adding load-bearing wheels.
Finite Element Analysis of Short-edge Distance of Fastener Holes in Composite Laminates
Authors: Zhao Luchun , Zhao Zhiqin
Published: October 2020

In the production process of aircraft structures, due to design defects or the accumulation of tolerances in part manufacturing and assembly, structural short margins appear at the mechanical joints of composite laminates. In this paper, the analytical method is used to analyze the hole edge stress of the composite material fastener, and the finite element analysis of the short edge distance of the fastener hole of the composite laminate structure is carried out. The hole edge stress and residual net of the structure after the short edge distance. The stress distribution of the cross-section is analyzed to discuss the changes of the stress and strain at the edge of the hole after the short margin of the composite laminate to determine the effect on the strength of the aircraft.
Research on the Fretting Slip Characteristics of Interference Fit Surface of Train’s Wheelset Running in Heavy Loads
Authors: Song Jianfeng , Song Younian , Wang Wenwu , Dong Yonggang
Published: October 2020

Running under the condition of heavy loads and accelerating status, the fretting damage of wheelset interference fit surface brings great hidden danger to the running safety of the train. Based on heavy loads train equipment parameters and running conditions by using the finite element software ABAQUS finite element model is established and simulated by different axle load and wheel inner hole under the conditions of different amount of interference with the axle wheel seat interference fitted surface fretting slip three-dimensional distribution, and the interference fit different axial location wheel revolving process of three feature points in axial and tangential fretting slip. The results show that the axial fretting slip of the edge of the interference fit surface is much larger than that of the middle, and the outer side is larger than the inner side, with a maximum value 22 µm; tangential fretting slip of interference fit surface reaches the maximum value 9.8µm, when the node rotates by about 270°. The influence of the value of shrink fit on fretting slip is more obvious than that of loads on the axle of the wheelset.
Research on the Dynamic Characteristics of Magnetic Bearing-rotor System with Auxiliary Bearing
Authors: Ma Lin , Wang Shijun , Wang Peng
Published: October 2020

Non-linear factors such as magnetic force and rub-impact force are comprehensively considered on the basis of the classic Jeffcott rotor system model, and the dynamic model of the magnetic bearing-rotor system is established. The dimensionless motion equation is obtained by introducing dimensionless parameters. The pattern types and distribution regions of adjacent fundamental periodic motions of the system are obtained based on multi-objective and multi-parameter co-simulation analysis, and the dynamic behaviour is analysed through three-dimensional bifurcation diagram, two-parameter bifurcation diagram, single-parameter bifurcation diagram and axis locus diagram. The reasonable matching range of parameters of system and speed ratio is obtained in this paper, which optimizes the structural parameter design of the rotor system and determines its reasonable and stable working interval.
Advances in Automatic Hexahedral Meshing
Authors: Li Chentao , Qiang Sheng , Hua Xia
Published: October 2020

The problem of Automated hexahedral meshing has been a puzzle of mesh generation research for years. A great deal of effort has been made on how to generate high-quality hexahedral mesh automatically. The conflicts between different requirements of the mesh provide the challenge. The paper systematically reviews the requirements of the hexahedral meshing challenge, sums up the various approaches to solve the problem and their respective characteristics, analyzes the breakthroughs in recent research, especially in multi-subdomain and strebel differential method. It finally points out that the development of geometric aspects and optimal transmission theory will be the main topics for the research on the organizational creativity in the future.
The Predictive Model of Decarburization Depth of Heavy Rail Billet Surface
Authors: Jiang Fanzhi , Kong Jianyi , Ouyang Degang
Published: October 2020

In order to determine the influence of heating technology on the decarburization depth of heavy rail billets, the surface decarburization of U75V and U71Mn heavy rail billets under different heating processes was experimentally studied. According to the experimental results, the predictive model of decarburization depth on the surface of heavy rail billet was established, and the errors between the results of the predictive model and those actually measured were less than 5%.
Structure Design and Performance Test of CO2 Scroll Compressor for Heat Pump
Authors: Zhou Dao , Zhao Panpan , Jia Lei , Yuan Xudong
Published: October 2020

Scroll profile design and shell strength design are important in the development of CO2 scroll compressors for heat pumps. In order to meet the multi-operating conditions of the heat pump, the non-clearance profile correction method and the clearance profile correction method are analysed, and the clearance profile correction method was adopted to complete the profile design. The safety factor design method was compared with the reliability design method, and the shell of the CO2 scroll compressor for heat pump was designed based on the reliability design method. The test results show that the scroll tooth with clearance correction method meets the design requirements of heating capacity of 4.8kW±10%, the energy efficiency ratio is not less than 4.6, and the shell structure with 99.38% reliability can meet the structural safety requirements.
Effects of Wall Wettability on the Interaction between Vapor Bubbles in Pool Boiling
Authors: Guan Geng , Shan Xiaopeng , Nie Deming
Published: October 2020

The interaction between vapor bubbles resulting from phase change in pool boiling was simulated through a two-phase lattice Boltzmann method. Two heated plates with constant heat flux were used to serve as the nucleate sites. The effects of wall wettability were examined. In doing so, three types of surface were taken into account, i.e. the hydrophilic surface, neutral surface and hydrophobic surface. It has been shown that the effects of wettability on the interaction between bubbles are significant in terms of the bubble mergence as well as the rate of heat transfer. In addition, the influence of the separation between the heated plates was also checked.
Numerical Simulation on Deposition of Atomization Droplet of Air-assist Boom Spraying in Air Flow
Authors: Zhong Wei , Zhou Huitao , Jia Weidong , Xue Fei
Published: October 2020

Air-assist Boom Spraying is a crucial technique and spray method of plant protection which has a significant effect on improving the efficiency of pesticide application and reducing droplet drift. Spraying drift is the main reason for the low utilization rate of pesticides, at the same time, the interaction of natural wind and the air bag wind is the main cause of spray drift. But at present, the regularity of spray droplet deposition and motion trajectory under the common influence of natural wind and air bag wind is not yet clear. The kinematics characteristics of the droplets deposition of air-assist boom spraying in the plants is investigated with numerical simulation method. The Phase Doppler Particle Analyzer (PDPA) is used to validate the numerical simulation results and it indicates that the deposition process can be well reproduced. The results show that the bigger droplets (>150 μm) get more kinetic energy from the vertical airflow and locate in windward side. These droplets are not sensitive to the horizontal airflow and are easier to deposit within a short time. The droplets with smaller size (<150 μm) are minimally influenced by the vertical airflow and suspend in the upside of the flow field. The vertical airflow not only prevents the horizontal airflow drift the droplets, but also introduces a vortex region near the canopy of the plants, which rotates the plant canopy and increases the droplet deposition on backside of the leaves. This study improves the understanding of the droplets deposition under the multi-wind fields and provides the theoretical basis for the innovation of the air-assist boom spraying system.
Modeling and Simulation of the Water Hydraulic Cylinder System Based on AMESim
Authors: Deng Xiangzhou , Sun Kailuan , Zhang Haiying , Zhang Yan , Li Tengfei
Published: October 2020

Pure water hydraulic is a green and pollution-free hydraulic technology, but the leakage in the cylinder makes its working efficiency greatly reduced. In this paper, a mathematical model of the water hydraulic cylinder has been established to analyze the factors of cylinder leakage. And a locking loop model with leakage module is established by AMESim software. Through simulation analysis, it is considered that the wall clearance of the water hydraulic cylinder is an important parameter affecting the leakage in the cylinder.
The 2nd International Scientific and Practical Conference on Mathematical Modeling, Programming and Applied Mathematics (Yaroslav-the-Wise Novgorod State University, Russia)
Authors: Eminov S I
Published: October 2020

At the Yaroslav-the-Wise Novgorod State University (Russia, Veliky Novgorod, ul. Bolshaya Sankt-Peterburgskaya, 41) on November 5-6, 2020, the International Scientific and Practical Conference “Mathematical Modeling, Programming and Applied Mathematics” will be held for the second time. Major scientists from Moscow and St. Petersburg, Kazan and Voronezh and Tver, and other cities of Russian Federation and from Belarus, Bulgaria, Kazakhstan, Ukraine, China, USA, Egypt, submitted their applications and articles. Despite the difficult situation associated with the spread of COVID-19, the interest in the conference is quite considerable.

The scientists – participants of the conference – present their latest scientific achievements, exchange experience and discuss issues of mathematical modeling in applied mathematics, programming, physics. Also, the conference participants will analyze and evaluate innovative solutions in terms of their relevance, effectiveness and prospects for further development.

The conference will include plenary sessions and 8 scientific sections. An auditorium equipped with the necessary computer equipment for online broadcasting is provided for each section.

List of International Program Committee, Organizing Committee, Editorial Committee, Invited Speakers and Organizing Institution are available in this pdf.
Information-analytical semantic model of an expert system for studying the co-evolution of the sociotechnical landscape in digital reality
Authors: Artemenko M V , Budanov V G , Korenevskiy N A
Published: October 2020

Currently, the development of society is largely determined by the expansion of digital technology into various social practices. Prediction and management of the co-evolution of society in digital reality is determined by the need to ensure sustainable development of society and adequate satisfaction of practices with information technology. The aim of the study was the development and pilot study of the capabilities of the information-analytical semantic model of an expert system for the analysis and management of socio-technical landscapes (STL) in digital reality. The network semantic structure of the knowledge base with unified decision modules in network nodes is substantiated. An enlarged diagram of the model is given and its functioning is described. Examples of the pilot application of the crucial modules of the expert system are examined: social practice “medicine” and digital technologies: “Artificial Intelligence”, “Information Technology”, “Mobile Technologies”, “Internet of Things”, “Big Data”. There are sharp changes in the ratios of feasibility and demand for technologies that occurred in the first half of 2020 compared to 2019 (which is associated with the consequences of the COVIN-19 pandemic). It is shown that the STL reaction is modeled by a transient process characteristic of the vibrational link.
A measure of basis efficiency at solving the Schrödinger torsion equation. Reaching the variational limit
Authors: Belov A N , Turovtsev V V , Fedina Yu A , Orlov Yu D
Published: October 2020

The procedure of the numerical solution of the Schrödinger torsion equation in matrix form in the planar wave basis set was considered. The concept of the largest level number that has reached the variation limit for a given number of basis functions was introduced as a quantitative measure of the basis efficiency. The rate of convergence to reliable values of levels and transitions has been studied. The problem of the maximum possible energy level number computed with the required accuracy for a given basis size has been solved. It was demonstrated that the number of levels that have reached the variational limit has linear relationship with the number of basis functions, and the angular slope coefficients of such dependencies are quite close to each other and equal to roughly 0.96. This allows prediction of the accuracy of the calculation method and conscious choice of the basis power.
Thermally expanded graphite from graphite nitrate cointercalated with ethyl formate and acetic acid: morphology and physicochemical properties
Authors: Berestneva Yu V , Raksha E V , Voitash A A , Arzumanyan G M , Savoskin M V
Published: October 2020

Triple graphite nitrate cointercalation compound with ethyl formate and acetic acid was synthesized and used as a source of the thermally expanded graphite. The effect of the drying regime of the cointercalation compound on its surface morphology as well as ability to the thermal expansion was investigated. Complex studies of the microstructure, morphology, and quality of the obtained thermally expanded graphite by XRD, TEM, and Raman spectroscopy showed that as compared to the initial graphite TEG is less ordered, has a multilayer and insufficiently ordered structure without visible surface defects.
Designing reverse converter for data transmission systems from two-level RNS to BNS
Authors: Bergerman M V , Lyakhov P A , Voznesensky A S , Bogaevskiy D V , Kaplun D I
Published: October 2020

In this paper, we present a reverse conversion from a two-stage Residue Number System (RNS) to a Binary Number System (BNS) with a special set of level 1 modules {2
α1, 2
α2 − 1, …, 2αn
− 1} and level 2 modules {2
β1, 2
β2
− 1, …, 2
β
k
− 1}. The proposed method is based on the Chinese Remainder Theorem (CRT) with fractions and using a calculation method that uses constant multiplications to speed up calculations. This article discusses the simulation of FPGA reverse conversion to a two-stage RNS using the proposed method and the standard CRT using adders, their comparison of latency and hardware costs.
The shift operators related to the Fourier cosine and sine transforms and visualization of their action
Authors: Britvina L E
Published: October 2020

We consider the shift operators generalized by the convolutions for the Fourier cosine and sine transforms. Three out of four considered operators are not the generalized shift operator of the Levitan’s type. The basic properties of the shift operators are presented. The GeoGebra applets have been created to visualize the actions of the shift operators.
The decay mechanism of 1,1,2,2-tetranitroxyethane according to theoretical calculations
Authors: Chachkov D V , Egorov D L , Nikolaeva E V , Shamov A G , Khrapkovskii G M
Published: October 2020

The geometric structure was determined and the mechanisms of thermal decomposition were studied using the quantum-chemical method of the density functional B3LYP/6-31+G (2df, p) for 1,1,2,2-tetranitroxyethane and structurally similar 1,2-dinitroxyethane and nitroxyethane molecules: O-N homolytic decomposition, α-elimination of HNO2 and various variants of β-elimination of HNO3. It is established that the radical mechanism is the main channel for the gas-phase decomposition of the studied compounds.
Notes about the linear complexity of cyclotomic binary sequences of order four over a finite field of odd characteristic
Authors: Edemskiy V A , Sokolovskii N S
Published: October 2020

In this paper, we investigate the linear complexity and the minimal polynomial of cyclotomic binary sequences of order four over a finite field of odd characteristic. The sequences considered are determined on the basis of two cyclotomic classes of the fourth order. We show that they have a high linear complexity.
Distributions of silicon implanted in GaN epitaxial layers
Authors: Fedorov D G , Seleznev B I , Zhelannov A V
Published: October 2020

Ion-doped layers of n+ - GaN were formed with a high degree of activation of the embedded impurity. Si+ ion implantation was performed in GaN epitaxial layers grown by MOCVD. Profiles of embedded silicon in gallium nitride were calculated. The experimental profile obtained by secondary ion mass spectrometry is compared with the calculated one. Optimal implantation modes were determined, the implantation dose is 1015 cm−2, and the energy is 50 keV. Activation of the embedded impurity was performed by high-temperature photon annealing in a nitrogen medium using SiO2 and Si3N4 protective coatings. The influence of the annealing temperature on the morphology of protective coatings is considered. The SRIM program was used to simulate the process of ion implantation of silicon at the interface of the AlGaN/GaN heterostructure through SiO2 dielectric films of different thickness. Ohmic contacts were formed on the ion-doped basis of the Ti/Al/Ni/Au metallization system. The calculation of the contact resistance of ohmic contacts showed that the use of ion doping through a 50 nm thick silicon dioxide film reduces the contact resistance from 1.2 Ω·mm to 0.8 Ω·mm. The use of ion implantation technology in the manufacture of diode structures reduces the direct voltage drop and the minimum voltage drop is achieved when using implantation through a 50 nm SiO2 mask, this is due to the location of the maximum distribution of the implanted impurity at a depth corresponding to the occurrence of a two-dimensional electron gas.
Creation of aerosolized detergent compositions for cleaning high-precision metal mirrors
Authors: Filin S , Rogalin V , Kaplunov I , Satayev M
Published: October 2020

We report on a studies on the possibility of extending the service life of products of non-ferrous metals by physical and chemical treatments with specially created azeotropic compositions. These studies were carried out on high-precision copper mirrors for high-power CO2 lasers, exposed during operation to different climatic influences, worsening of their operational characteristics. The results obtained in this paper can be applicable for physical and chemical cleaning of such mirrors and other high-precision parts from non-ferrous metals. The work is devoted to the creation of aerosol detergent compositions intended for use during the operation of mirrors in the field climatic conditions. It is shown that when aluminium and tin-plate aerosol containers are used, compositions that are used to clean metal mirrors should not contain chlorine-substituted hydrocarbons or even “traces” of water and hydroxyl ions. In addition to copper mirrors, optical elements made of other materials were also studied in this work.
Computer modeling of a biharmonic oscillator
Authors: Frolov D A , Safin A R , Udalov N N , Sotskov V A
Published: October 2020

In this work computer modeling of a two-mode Colpitts oscillator operating in the phase locking of two modes was carried out. Modeling of an oscillator operating modes and the experiment allow to draw a conclusion about possibility of phase noise reduction in a stationary synchronous biharmonic mode that can be used in the frequency stabilization task.
Invariant description for batch version of UCB strategy for multi-armed bandit
Authors: Garbar S V
Published: October 2020

We consider a variation of upper confidence bound strategy for multi-armed bandit in batch processing setting. Invariant descriptions with the unit control horizon are obtained for upper bounds in the strategy and for regret. A set of Monte-Carlo simulations are performed for different settings of MABs to determine the minimax regret for multi-armed bandits with different configurations.
The lamb shift
Authors: Granovskii Ya I
Published: October 2020

In this paper I have returned to the coordinate representation of Coulomb propagator and wave function significantly simplified thanks to spiral choice of Dirac matrices (see Appendix). The series in Zα appeared as hypergeometric functions, division to soft and hard photons and their sewing became superfluous etc. The nonrelativistic part of shift is shown completely due to contribution of only one partial wave P
1/2 of propagator.
Magnetic nanoparticles in biocatalysis
Authors: Grebennikova O , Sviridova I , Matveeva V , Sulman M
Published: October 2020

The properties of enzymatic systems based on horseradish root peroxidase immobilized on magnetic particles were studied. Magnetic Fe3O4 nanoparticles were synthesized by co-precipitation. Then, horseradish root peroxidase was immobilized on their surface in two ways by covalent crosslinking. For this purposes, in the first case, Fe3O4 was sequentially treated with tetraethoxysilane, 3-minopropyltriethoxysilane, glutaraldehyde and HRP. In the second case, before immobilization of HRP, 3-minopropyltriethoxysilane, glutaraldehyde and HRP were sequentially deposited onto the support surface. The activity of the synthesized biocatalysts was evaluated spectrophotometrically in the oxidation reaction of 2,2’-azino-bis (3-ethylbenzothiazolin-6-sulfonate) ammonium with hydrogen peroxide. The kinetic parameters K

m
and V

max
were also calculated for all types of catalysts, including native HRP. Among all biocatalytic systems, the best values, compared with the native enzyme (K

m
= 4 mmol/L and V

max
= 12.6 · 10−4, mmol/L·s), were obtained for the first type of biocatalyst (K

m
= 5 mmol / L and V

max
= 2.5 · 10−4, mmol/L·s). It was also determined that the optimum pH is 7.2.
Cyclic Scheduling for Parallel Processors with Precedence Constrains
Authors: Grigoreva N
Published: October 2020

The goal of this paper is to prepare algorithms of the cyclic scheduling problem, in which some set of jobs V is to be repeated an infinite number of times. We consider the multiprocessors problem when a set of jobs is done on identical parallel processors. Cyclic scheduling problems arise (for example) in manufacturing, timesharing of processors in embedded systems. The goal is to find a periodic schedule that minimizes the cycle time under precedence constraints. Although the problem is NP-hard, we show that the special case, where the precedence graph G is a tree or there are only two processors and all jobs have a unit processing time, can be solved in polynomial time.
Investigation of fine metal films of the Ni-Al system by physical methods
Authors: Ishkov A , Malikov V
Published: October 2020

The article describes the results of investigations of ultrathin Ni-Al films, obtained by the resistive method of thermal evaporation and having characteristic islands sizes of 700-1000 nm with a film thickness of about 500 nm. The work presents a method for producing a film using an installation for creating a high vacuum and subsequent film deposition. Investigations of the obtained film sample were carried out with the help of an optic microscope, a scanning probe microscope and a Fourier analyzer. Kinetic characteristics and relief of the film, characteristic islands sizes are established, the search for regularities in the island structure of films is carried out, and its electrical conductivity is determined.
Study of a secondary power source with hysteresic control, comparison of theory and practice
Authors: Ivanov A D
Published: October 2020

This article presents the comparison of the operation of the model and the prototype of a secondary power source with hysteresic control. The principles of operation of this type of control are considered. Timing diagrams and oscillograms of the model and prototype are presented. Comparison results are presented. On the basis of the prototype, theoretical principles of the operation of hysteresic control are confirmed.
Computer simulation of the multiplicative method for the formation of digital spectrozonal images
Authors: Kalitov M A , Kornyshev N P
Published: October 2020

The article discusses the features of the formation of digital spectrozonal images corresponding to narrow registration zones. TIt analyses the processes of signal transformations with the multiplicative method of forming digital spectrozonal images. The results of computer modeling are discussed with the aim of qualitative and quantitative comparison of images obtained with differential and multiplicative digital spectrozonal imaging. An example of images of test objects obtained by the differential and multiplicative method from the original digital spectrozonal images is given.
Temperature field of SiC – refractometric detector under conditions of visualization of a heated gas stream
Authors: Karachinov V A , Djerenov I G , Evstigneev D A
Published: October 2020

As part of a computer experiment using the finite element method, a technique was developed for visualizing the temperature morphology of the temperature field of a refractometric detector based on single-crystal silicon carbide when interacting with an air stream heated to temperatures T = 400 ÷ 1300 C. It is noted that the maximum values of the detector surface temperature at angles of attack of the stream φ = 0 ÷ 90 degrees turned out to be 5-6 times less than the temperature of the air flow. Experimental studies using methods of brightness television pyrometry showed satisfactory agreement with model concepts.
Specific features of the physicochemical properties of welded titanium nickelide
Authors: Khlopkov E A , Burkhovetskiy V V , Kurushkin D V , Ostropiko E S , Chernyavskaya N V , Shkuratov B E , Lyubomudrov S A , Vyunenko Yu N
Published: October 2020

The paper analyzes the strength characteristics of welded joints made of TiNi alloy with a shape memory effect. Comparison of the level of tensile strength of welded samples made by the TIG method in an Ar and He medium was carried out using a universal machine Instron 5985. The study of the material structure was carried out on longitudinal sections using a JSM-6490LV electron microscope. The analysis of the chemical composition of the material under study in local volumes was carried out using an INCA Penta FETx3 energy dispersive attachment. The calorimetric parameters of the original and welded samples were obtained using a differential scanning calorimeter METTLER TOLEDO 822e.
The effect of molecular structure on the O – NO2 bond dissociation energy and the activation energy of the radical decay of cellotriose nitrates
Authors: Khrapkovskii G M , Garifzianova G G , Egorov D L , Chachkov D V
Published: October 2020

The molecular structure was determined using the method B3LYP/6-31+G(2df, p), and the dissociation energies of the O – NO2 bond in dimethylcellobiose and cellotriose nitrates were calculated. It has been established that the O – NO2 bonds attached to the secondary carbon atom at C2 are the least strong in cellotriose nitrates. With an increase in the degree of substitution, a slight decrease in the dissociation energy of radical decay is observed. The results can be used to discuss the mechanism of thermal decomposition of cellulose nitrates.
Two-alternative optimization of moderate batch data processing
Authors: Kolnogorov A V
Published: October 2020

We consider optimization of moderate batch data processing in the framework of Bernoulli two-armed bandit problem with indefinite control horizon. We assume that there are two alternative processing methods with different a priori unknown efficiencies which are caused by different reasons including those related to legislation. One has to find the most efficient method and to provide its predominant usage. The arising batches of data with close properties have moderate and possibly uncertain sizes. The problem is considered in minimax setting. According to the main theorem of the game theory minimax risk and minimax strategy are searched for as Bayesian ones corresponding to approximately the worst-case prior distribution concentrated on the finite set of parameters. Numerical experiments show that this approach provides good approximations of minimax strategy and minimax risk.
Non-stationary model of incompressible viscoelastic Kelvin-Voigt fluid of higher order in the Earth’s magnetic field
Authors: Kondyukov A O , Sukacheva T G
Published: October 2020

This work is aimed at studying a higher-order model of magnetohydrodynamics in regards to external effects on a fluid. The first initial boundary value problem for a system of higher-order Kelvin-Voigt equations in the Earth’s magnetic field is considered. The study was carried out in the framework of the theory of Sobolev type semilinear equations. The existence of quasistationary semitrajectories of the indicated problem is proved and its phase space is described.