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This paper studies the dynamic time-varying formation control of multi-agent systems. Aiming at the unmanned vehicle systems, based on the static time-varying formation in literature [18], a multi-agent dynamic time-varying formation control based on consistency is put forward. Additionally, the sufficient conditions for the agreement and the steps for solving the control parameters are given. The simulation is conducted to prove the effectiveness and robustness of the theoretical results.

This paper was retracted by IOP Publishing on 12 December 2018. This paper was published due to a technical error and was not intended to be included in this journal. Retraction published: 8 February 2019

The paper deals with state estimation of nonlinear stochastic dynamic systems. In particular, the iterated extended Kalman filter is studied. Three recently proposed iterated extended Kalman filter algorithms are analyzed in terms of their performance and specification of a user design parameter, more specifically the step-length size. The performance is compared using the root mean square error evaluating the state estimate and the noncredibility index assessing covariance matrix of the estimate error. The performance and influence of the design parameter, are analyzed in a numerical simulation.

Under the development goal of “Carbon Peak, Carbon Neutralization”, the concept of novel power system is proposed. Its representative features include AC/DC interconnection of power grid and large-scale access of new energy power stations. Under these characteristics, higher requirements are put forward for the short-circuit current breaking capacity of the circuit breaker. The DC component of short-circuit current and the injection of new energy into the system short-circuit current cannot be ignored. Based on the 330kV local power grid in Northwest China, this paper studies the power grid operation mode, DC component of short-circuit current and the influence of photovoltaic power station on short-circuit current. The influence law of DC component of short-circuit current on the actual breaking capacity of circuit breaker and access of photovoltaic power station on the short-circuit current are summarized. It can provide a theoretical basis for the selection of circuit breaker in novel power system.

There exists a large number of high-energy electrons and various plasma waves in the Earth’s radiation belts. The chorus waves, as a kind of whistler-mode waves can cause electrons acceleration and loss by wave-particle interactions, thus playing a vital role in the dynamic evolution of the radiation belts. To improve our understandings of such mechanisms and facilitate people to anticipate the dramatic variation of space environment, we utilized the wave and field data from Van Allen Probes to statistically study the acceleration and loss timescale of electrons by chorus waves. The first part in this paper presents the temporal-spatial distribution of the chorus characteristics and background field parameters. The second part exhibits the loss and acceleration timescales of electrons caused by chorus waves. The main results in this paper includes: As geomagnetic activity and L shells increase, the pitch angle and momentum diffusion of electrons driven by chorus waves strengthens. The dramatic acceleration of electrons by chorus waves exists in the region with lower fpe /fce . Compared with keV electrons, MeV electrons are hard to be scattered by chorus waves, and electrons be precipitated into the atmosphere within several hours during highly disturbed times.

Aiming at the limited switching frequency of traditional silicon (Si) based devices and its huge switching loss when working under the high-frequency conditions, this paper proposes a synchronous buck converter based on GaN power devices with good switching performance and low loss. In this paper, the detailed parameter design method and simulation circuit were given. This paper also conducts thermal stability analysis. Finally, the simulation experiment proves the feasibility and effectiveness of this theory.

Due to the increasing share of wind energy in electricity generation, wind turbines have to fulfil additional requirements in the context of grid integration. The paper examines to which extent wind turbines can provide positive control power following the related grid code. The additional power has to be obtained from the rotating flywheel mass of the wind turbine's rotor. A simple physical model is developed that allows to draw conclusions about appropriate concepts by means of a dynamic simulation of the variables rotational speed, torque, power output and rotor power. The paper discusses scenarios to provide control power. The supply of control power at partial load is examined in detail using simulations. Under partial load conditions control power can be fed into the grid for a short time. Thereby the rotational speed drops so that aerodynamic efficiency decreases and feed-in power is below the initial value after the control process. In this way an unfavourable situation for the grid control is produced, therefore the paper proposes a modified partial load condition with a higher rotational speed. By providing primary control power the rotor is delayed to the optimum rotational speed so that more rotational energy can be fed in and fed-in power can be increased persistently. However, as the rotor does not operate at optimum speed, a small amount of the energy yield is lost. Finally, the paper shows that a wind farm can combine these two concepts: A part of the wind turbines work under modified partial load conditions can compensate the decrease of power of the wind turbines working under partial load conditions. Therefore the requested control power is provided and afterwards the original value of power is maintained.

The management of teaching quality is subordinate to and serves the main teaching activities of colleges and universities, which is an important means to improve the teaching quality. Today, we can make college teaching quality management more dynamic, accuracy and objectivity with the gradual construction of big data environment. We can maintain the right direction and achieve the best results of teaching activities in the continuous rectification give full play to its service function by reasonable evaluation, scientific prediction and effective intervention. This paper focuses on three key issues of evaluation, prediction and intervention in the construction of service-based teaching quality management system, discusses the main contents, process and methods related to teaching evaluation, and lays a theoretical foundation for the realization of service-based teaching quality management system in the big data environment.

Binary de bruijn sequences are studied by many researchers since it has many applications such as in DNA sequencing, robotics, and radar. In this paper we study the properties of binary de bruijn sequences in term of permutation. We showed that it has a nice property that we hope it will be useful in further research.

Tensor decomposition methods are widely used for solving high-dimensional and multi-dimensional problems. These approaches have a huge potential for reducing computational costs in the simulation of electronic circuits and in the CAD systems for electronics. Simulation of modern radio-frequency (RF) circuits, especially for RF integrated circuits, is one of the areas of extensive scientific research and development. The main problem of analysis methods for circuit design of RF electronics is the significant computational costs associated with the high dimensions to be solved. This paper shows that the computational costs of circuit design are largely determined by the costs of solving a system of linear algebraic equations (SLAE). The problems of the solving of SLAE are indicated in the paper. Further development of methods for solving and reducing computational costs requires the use of new approaches, one of which is proposed in this paper. The article presents the developed algorithm for converting a second-order matrix into a higher-order tensor. In this paper algorithms and software tools for tensor decompositions, as well as methods for solving SLAE in the representation of equations in tensor format are investigated. The results of numerical experiments and the results of comparison with traditional methods are presented.

As one of the basic areas of research for the development of a highly sensitive magnetic sensor, the present authors have fabricated bulk Bi-Pb-Sr-Ca-Cu-O magnetic sensors by use of the shock compaction method, as a new fabrication technique for high-critical temperature superconductors. Values of the thickness t of the sensors, under a shock compaction pressure P of 4 GPa, are systematically changed between 0.3 and 1.1 mm to investigate the magnetic sensitivity S of the sensors. It was found that the value of S increases as the value of t decreases. The value of S for a magnetic sensor (1.1 mm in width, 8.7 mm in length) was about 62 %/(104 T) over the range of measurement of the magnetic field Bmeas which varied from 0 to ±5×10-4 T, under a constant value of the bias magnetic field Bbias of 20×10-4 T. Namely, it was approximately 62 times greater than that of giant magnetoresistance sensor. In addition, the present paper examined the dependence of resistivity ρ(T) on temperature, the dependence of ρ(T=77.4 K) of the sensor on current density, the dependence of Son t, and the dependence of measured resistance of the magnetic field Rmeas on Bmeas.

In order to improve prediction accuracy of water pump operating state, a chaotic prediction model of the pump vibration data based on improved particle swarm optimization of support vector machine is proposed in this paper. Firstly, a grouping optimization strategy particle swarm algorithm based on cosine function is proposed. Then, the training set is obtained on the time series of vibration data by phase space reconstruction. Secondly, The improved particle algorithm is used to optimize the penalty parameters, insensitive loss coefficient and width parameters of support vector machine. Then, a prediction model of vibration data is established by using support vector machine combined with training set and optimal parameters. Finally, the operating state of the pump is predicted according to pump vibration measurement and evaluation method. Compared with the method of linear decreasing weight strategy, the method proposed in this paper is more accurately.

Reference materials for the Rockwell, Brinell and Vickers hardness scales are fundamental for the Brazilian industrial sector. Mechanical property Hardness is the most common mechanical test used for quality control of raw materials in finished products as well as in research and development of new products and materials. A description of the main findings of two studies and the revalidation of the last on the demand of hardness reference blocks in Brazil is presented. This paper shows national demand of hardness reference blocks could be supplied on a large scale by Inmetro´s Force Laboratory.

Aiming at the problem of efficient reuse of existing parts CNC process, this paper presents a reuse method of the part CNC process based on 3D feature matching. It’s assumed the part which is the most similar to the 3D features of the new part has been found in the CNC history library. To reuse the CNC process of the existing part, the CNC programs and machining parameters of the existing part are imported into the new part as the machining template firstly, then the improved 3D polar radius surface moments are used to extract the 3D shape and position vectors of the machining area of each CNC program of the existed part and each face of the new part, finally the weighted Euclidean distance is used as a metric to find the most similar matching of each machining area in the new part, and the matching result is optimized by the greedy algorithm based fragmented surface matching algorithm and the overall optimization algorithm. Hundreds of sets of 3D feature similar parts were verified in the prototype system based on this method. The results show that this method can effectively reuse the existing CNC parts, and significantly improve the efficiency of CNC programming.

A comparison of multiple quasi-spherical EFP warhead tests conducted during different seasons of the year revealed that EFP velocities in the cold season were low. In this paper, the experimental phenomenon is analyzed theoretically base on the principles of EFP and flight dynamics. Due to the difference of air density caused by the different temperature, the aerodynamic drag of EFP with the same aerodynamic shape and initial velocity is obviously different. Because of the hypervelocity of EFP, The impact velocity of EFP on target is also significantly affected after flying over 100 meters. In the paper, the flight velocities of a quasi-spherical EFP at different temperatures is calculated by MATLAB, which is in good agreement with the experimental results. It is necessary to consider the change of environment temperature in engineering practice of quasi-spherical EFP warhead in order to improve kinetic energy margin.

Chained decomposition will take place in terms of overheat of high concentration hydrogen peroxide, which will further cause explosion, in the electric pump pressurized liquid propellant rocket engine, which takes hydrogen peroxide of high concentration as oxidizing agent, the design of oxidant pump should consider safety factor for temperature rising of hydrogen peroxide and the influence of pump efficiency on quality control of motor system simultaneously. It’s very important to know the effect of sealing ring gap at the bottom of impeller on temperature rising of bearing chamber and pump efficiency. So, this paper firstly establishes mathematical modal about the effect of sealing ring gap on temperature rising of bearing chamber and pump efficiency loss, to gain influencing curve, and then it analyzes parameters of cooling flow and mechanism of temperature rising, and give reasonable gap values, which take both safety and efficiency into account. Finally, 3D simulation calculation is carried out through pumplinx to verify the accuracy of this influence model.

Based on the perspective of ITT, the development of cross border e-commerce (hereinafter referred to as CBEC) is directly related to many industries, which promotes the employment and development of many industries, such as logistics, it, production, etc. Therefore, CBEC accounts for a large proportion in economic development. With the improvement of e-commerce platform, the traditional international trade (hereinafter referred to as ITT) has gradually changed to CBEC. In the perspective of ITT, the “Internet plus foreign trade” CBEC is a modern sales way, which caters to the characteristics of the fragmentation of sales orders and the individualization of product demand. Therefore, the average annual growth rate of CBEC in China exceeds 30%, which has become a new direction of ITT transformation and upgrading. Through CBEC, ITT has broken through the limitation of time and space, which has gradually reduced transaction costs. Therefore, computer CBEC has a positive impact on ITT. First of all, this paper analyzes the role of CBEC development. Then, this paper puts forward some problems. Finally, some suggestions are put forward.

In today’s era of rapid economic development, China’s Internet is also developing rapidly, and intelligence is becoming more and more common in people’s daily life, which also promotes the intelligence of my country’s electricity data collection. This paper designs a power data acquisition system based on the power Internet of Things. Through the analysis of the power Internet of Things and its relationship with the smart grid, a data acquisition system is constructed with three parts: smart meters, concentrators and data management systems. And use GPRS and VPN to analyze, explain how to analyze the collected data.

We have been developing a Superconducting Fault Current Limiting Transformer (SFCLT) with the functions of both superconducting transformer in normal operating condition and superconducting fault current limiter in fault condition. As the Step-5 of our SFCLT project, in this paper, we designed and fabricated a 2 MVA class HTS-SFCLT using YBCO coated conductors with the ratings of 3-phase and 22 kV/6.6 kV. The developed HTS-SFCLT is characterized by a hybrid structure of HTS coils using YBCO, YBCO/Cu and Bi2223 tapes for design flexibility as both the superconducting transformer and the superconducting fault current limiter. Fundamental tests of the HTS-SFCLT were carried out, and its design parameters as a superconducting transformer were verified., Eucas '09: The 9th European Conference on Applied Superconductivity (Dresden, Germany, 13–17 September 2009)

A prototype of a low-cost GNSS receiver assembled on base of the u-blox ZED-F9P module is described in the paper. The original low-cost GNSS receiver (OGNSS-R) allows made the parallel registration of 184 channels in the entire frequency range (1176 ÷ 1610 MHz) of the main GNSS (GPS, GLONASS, Galileo, Beidou) and recording raw data of carrier-phase, pseudorange (code) and signal strength measurements. The obtained data processing allows to calculate the slant total electron content (TEC), TEC variations and other most popular TEC-based indices of ionospheric activity. The comparative studies of these parameters and similar parameters obtained by simultaneous measurements on the professional geodetic GNSS receiver Trimble Alloy (KZN2 station of the IGS network) were preformed. The analysis showed the median value of the signal strength at the L1 frequency for the KZN2 station are 8% higher than that at the low-cost GNSS receiver based on the u-blox ZED-F9P module (KZN2–48.75 dBHz; OGNSS-R – 45dBHz). For the L2 frequency that difference is less than 2% (KZN2–49.4 dBHz; OGNSS-R – 48.5 dBHz). The median levels of relative slant TEC and TEC-based indexes of the ionospheric activity obtained by the Trimble Alloy receiver at KZN2 station are 25÷50% lower than for the u-blox ZED-F9P receiver. Thus, the using of starter kits such as the simpleRTK2b debug board based on the u-blox ZED-F9P module described in the paper, is really actual for creating a permanent network of GNSS-stations and/or for carrying out field measurements in experimental campaigns.

The frequency based substructuring (FBS) method allows the combination between the experimental and analytical frequency response function (FRF). The combined FRF is then used for calculation of the dynamic behaviour of an assembled structure which usually consists of a large number structural components or substructures. However, the accuracy of the dynamic behaviour calculated using the FBS method relies heavily on the quality of experimental FRF data of the interfaces on which, in practice, it is very problematic to be attained. Furthermore, in most cases, some parts of rotational FRF data are not included in the FBS method due to the complex measurement process. The exclusion of the rotational FRF data will usually lead to numerous errors in the combined FRF data. Therefore, this paper proposes a new frequency response function (FRF) coupling of the FBS method that may uniquely address the difficulties and improve the quality of predicted results of the FBS method. The proposed coupling was formulated based on the finite element method, model updating method and FRF synthesize method. The finite element model of the physical test substructure was developed and reconciled based on the mode shapes obtained from experimental modal analysis. The FRF synthesize method was performed on the updated finite element model to obtain a complete matrix with a full degree of freedom FRF data containing all the translational and rotational FRF data required. It was found that the proposed coupling has allowed generating full translational and rotational FRF data. The generation has improved significantly the FRF coupling process and the quality of the predicted dynamic behaviour of the FBS method.

In recent years, with the rapid development of the Internet in China, online transactions have grown greatly. For example, OTAs with a large number of hotels have accumulated a large amount of hotel data and user consumption data. And the online sales of hotels is the basis and core of revenue management. Time series prediction has always been one of the main application fields of machine learning algorithm. From the classical traditional time series prediction methods to long-term and short-term memory networks and closed-loop neural networks, the prediction ability is constantly improving. With the development of deep neural networks, convolution neural networks show superior performance in the prediction of time series. This paper proposes a new prediction model based on the improved WaveNet using not only the parameters of historical sales and hotel property, but also the parameters of holiday time and time position in the prediction range, which are processed by serialization. Simulation results are presented in details in this paper, where these results indicate the effectiveness of the proposed forecasting tool as an accurate technique.

This paper describes a novel boost converter to be used with energy harvesters that provide only low output voltages. The device is self-supplied from electric power delivered to its input. With peak power conversion efficiencies above 30% at start-up voltages down to 10 mV this circuit sets best values in comparison with the state-of-the-art. This is achieved by the novel combination of a Meissner oscillator, used as stand-alone in most low-voltage step-up converters today, with a forward converter usually applied in high power systems.

This paper investigates the characteristics of brief-term variety in wireless communications in the underwater environment. Nowadays, they are extensively used in experimental research related to underwater communication networks and channel estimations for an efficient link. From the first perspective, the main research exploration enquiry depends upon increasing the distance and frequency range. In this research work, an electric current method focusing on RF wave propagation is chosen. This technique in the seawater is produced by a couple of electrodes sensed by two receipt electrodes. The method can be an option as the waves show less effective refraction and reflection effecting in deep and shallow water.

The principle objective of this paper is to determine the concept of asymptotic regional boundary gradient observability to the case of diffusion system with Neumann boundary conditions. More precisely, for linear distributed parameter diffusion systems, we show that the sensors characterizations allow to reconstruct regional boundary gradient state in a boundary target subregion of the considered systems domain. Moreover, various interesting results associated with the selection of sensors are explained in specific and customized position situations respect to the asymptotic regional boundary gradient observability notion to be realized. Finally, we was clarified the existence of a dynamical systems that is not asymptotic boundary gradient observable in whole the boundary domain, but it may be performed on a part of boundary domain.

The application of tunnel robots in power tunnels is becoming more and more extensive. Due to various reasons, video jitter will inevitably occur during the inspection process, which will affect the real-time processing of subsequent images. In order to reduce the impact of video jitter and meet the requirements of real-time image processing, it is necessary to study fast video image stabilization methods. The traditional Kalman filtering algorithm has less computational cost, but it will cause a large estimation error when the system motion state changes. In this regard, the paper proposes an improved Kalman filtering algorithm, which changes the corresponding filter parameters by real-time estimation of a system in motion to reduce the estimation error. And this algorithm performs Harris corner extraction in the set feature dense area, and combines the PyrLK optical flow algorithm with the homography matrix to calculate the motion trajectory, which improves the calculation speed and accuracy of the algorithm. Experimental results show that this algorithm has better video stabilization effect and faster calculation speed compared with the traditional Kalman filtering algorithm, and can better meet the real-time image processing requirements in the inspection process.

Most of women in Desa Limbang Jaya work as songket weavers. Their products have good quality, but their level productivity is low, so it causes the income for them is low. There are characteristics that influence the level productivity of weaver. Path analysis is method that can be used to look for the characteristics that influence the productivity. In this paper, we use path analysis to find exogenous variables that effect directly and indirectly on endogenous variables. Exogenous variables in this paper consist of: age, education, work period, work motivation, work culture and business motivation. Endogenous variables consist of productivity and income. The obtained data by purposive sampling method consist of 104 songket weaver respondents. Characters that have a significant influence on the productivity of songket weavers in Limbang Jaya is education and business motivation. In the craftsman’s income, either with alpha 5% or 10%, no variable has a direct and indirectly significant effect.

Spectacular trends in the modification of the Xe 5s photoionization via interchannel coupling with confinement resonances emerging in the Xe 4d giant resonance upon photoionization of the Xe@C60, Xe@C240 and Xe@C60@C240 endo-fullerenes are theoretically unraveled and interpreted., Comment: 1 page, 1 figure. 2011 International Conference on Photonic, Electronic, and Atomic Collisions (Belfast, UK, 2011). Paper number We158

In this paper, a two-neuron system with inertia and delay is proposed firstly. a PD controller is then applied to the system for the purpose of improving its dynamical performance. Through the mathematical transformation, we extend the system to a four-dimensional one with only time delays. With the help of the associated characteristic equation of the mathematical model, suffcient conditions for ensuring the system stability are proposed. Furthermore, with the time delay as the bifurcation parameter, relevant requirements for the generation of Hopf bifurcation are derived. Then a series of numerical simulatiosns are carried out to justify the theoretical analysis and it is found that the application of PD control scheme helps to advance the bifurcation point dramatically through a slight adjustment of the controller parameters.

In this paper, the 3D visual display and generation of target in optoelectronic tracking are researched by simulation. 3ds max software is used to model the target, the target model is converted into code files by Deep Exploration and added into the system model. The key point is to associate the target model track and size ratio with the actual target to approach the real battlefield environment. The image data provided by the scene building is tracked by the internal image processing algorithm of photoelectric tracking such as the Canny-based edge tracking. The experiment will compare the tracking of the same target in same algorithm but different backgrounds, and the same backgrounds but different algorithm. Result can see that through the experimental data, the application of the simulated sky background, and the proportion relationship between real target and target in simulation scene, provides a high authenticity data support for the image processing algorithm of self-propelled gun photoelectric tracking system.

Nowadays, Teaching and learning activities in the world of education must always follow the development of technology. The use of these technologies will make these activities more effective and efficient. Gamification is part of innovation in education. In this research, gamification is used as a tool for studying activities in project management information systems subject. The method used is technology-based applied research. The Assessment Tool in this study uses Quizizz. Quizizz is used on midterms. This exam was attended by 29 students of the information systems department STMIK Royal. The questionnaire was made using a Mentimeter. The use of Quizizz has a positive impact. The level of student answers questions correctly is 51%. Then 66% prefer Quizizz as assessment tool compared to paper and google forms.

In this paper, we develop a new approach to analysing and designing the gradient coils for magnetic resonance imaging (MRI) scanners for medical applications. More specifically, a novel higher-order BEM which satisfies the continuity equation for the current density is proposed. We also present solution procedures for applying this method to the inverse problem whereby the divergence-free surface current distribution in the gradient coil is deduced from knowledge of the magnetic flux density in a prescribed region of interest. The novel BEM proposed is a non-traditional one, in the sense that the collocation points are given by the vertices of the triangular elements only and not all the BEM nodes used to define the boundary elements. Furthermore, the degree of the interpolation is one degree less than that of the geometry of the triangular elements employed, so that (for example) the linear boundary elements involve constant interpolation for the surface current density. Moreover, the present method can be easily extended in order to obtain any desired degree of the interpolation for the surface current density. Within the inverse problem, care must be taken to employ the optimal value of the Tikhonov regularisation parameter. Results are presented relating to various geometries of coil, obtained using linear, quadratic and cubic variants of the boundary element formulation; those obtained using the quadratic and cubic elements agree almost precisely, while those from the linear elements exhibit small differences from those of the higher-order formulations.

A significant number of papers investigate a propagation of intense two-color beam through air in conditions when inharmonic oscillations of valence electrons convert to a plasma nonlinearity. This paper extends the scope of analysis, examining more complex combinations of synchronized beams propagating through dielectric media: triple beam and a beam combined with quazi-static field. It is shown that adding a third harmonic to a mix of first and second ones does not show principal changes in interaction picture: all phenomena appear to be described well before. But adding a static field to an interaction scene shows new peculiarities in redistribution of pulse spectrum energy to infra-red wing of optical range.

The high-order modes and the moving wave characteristics of rotating thin shell are investigated in this paper based on transfer matrix method when the damping effects of the hard-coating layers are applied on the shell. Firstly, the dynamic model of the thin shell is obtained based on the Love theory, with introducing centrifugal force and Coriolis force. Then, the transfer matrix formulas of the shell with partially coated layers at different segments are obtained under the clamped-free boundary condition, in which the mechanical property of the hard-coating material is simplified to be linear and isotropic. The modal characteristics of the shell are calculated numerically. The obtained higher order modal frequencies of the partially coated shells are compared with those of the bare shell. The effects of the material parameters and locations of the hard-coating layers are also illustrated based on the different modal characteristics., great care should be taken in constructing both.

Increase in the development of missile technology and the need to control/monitor fast-moving prototypes for various purposes, forces the development of a ground station with automatic telemetry reception capability. The paper presents the preliminary results of the research of the automatic system of maintaining the continuity of communication between the ground station and the moving object. The advantage of the solution is the low weight and dimensions of the transmitting system and the resistance of the receiver to frequency shift resulting from the movement of the object. The receiving module was implemented on the basis of SDR technology together with an application using FFT. The application of the above solution allows for the implementation of the telemetry systems.

Low speed and high torque machines are widely used in industrial production, oilfield mining, wind power generation, etc. Low speed high torque motors have large internal space, in order to make full use of internal space this paper proposes a dual stator low speed high torque synchronous motor. The rotor adopts a surface-mounted permanent magnet rotor structure on one side, and a spliced reluctance rotor structure on the other side. A magnetic ring is added in the middle to make permanent magnet and magnetic resistance independent of each other. The motor has a special structure, and the loss distribution is different from that of a normal motor. The loss will affect the performance of the motor. This paper establishes the iron loss model considering the effects of alternating magnetic field, rotating magnetic field, and harmonics. Considering the influence of temperature on copper loss. Then establish a mathematical model of core loss and copper loss. Then studying the motor iron loss and copper loss distribution characteristics. Finally, the results are compared with the finite element method (FEM) to verify the effectiveness of the loss calculation in the paper.

The present paper solves the problem of quick detection of a change in the motion mode of an object moving along a complex trajectory. The process of the object movement is described by a hybrid stochastic model. To solve the problem, a sequential probability ratio criterion is applied. A distinctive feature of the proposed algorithm is the ability to make decisions on a limited set of values of the likelihood ratio function. The results of numerical experiments confirm the efficiency of the developed algorithm.

The paper presents data from an experimental study of the possibility of recycling polymer composites on the example of fiberglass and different thermoset binders. The goal is to remove the polymer matrix and obtain recovered fiberglass that is not inferior in properties to the virgin material. In this paper, considered the solvolysis method of the composite in the amino alcohols. As the medium used methyldiethanolamine and 3-aminopropanol-1. The dependence of the influence of the solvolysis time and the concentration of alkali metal hydroxide in the reaction medium on the strength of recovered glass fibers has been established. The solvolysis at a temperature of 180 °C and a catalyst concentration of 5 % for 6 hours was accepted as optimal regime. As a result of the research, a regime was obtained that allows recovering fibers with a tensile strength of 92 % of virgin fibers. The recovered fabrics were studied by thermal analysis and scanning electron microscopy. GFRP samples were obtained from the recovered fabrics by the VaRTM method. The flexural strength of composites made from secondary filler is 8.5% lower than the same material based on virgin fabric. Products of the polymer matrix degradation and fibrous fillers are released during recycling. These products could be used in chemical technology to produce, for example, binders components and secondary fillers for polymer composites.

Visualization and measurement of airflow detail structures is a difficult problem. In the past few years, high-speed DPIV has been used to capture the vortex structures on flapping robotic insect wings. Due to the inherent limitation in DPIV technique, important airflow activity in small scale vortical flow structures may be missed. In this paper, high-speed Schlieren photography was applied to vortical flow Visualization on a flapping robotic insect wings and then provided more information of vortical flow structures in detail. Based on the Schlieren image, quantified velocity vectors field was obtained by applying the variational optical flow method, which is able to be extending the potential applications to development flapping wings aircraft.

With the national policy of energy saving and emission reduction, microgrid technology has gradually entered into people’s daily life and received more and more technical and financial support. In this paper, we build an energy storage microgrid system based on a bi-directional DC/DC converter through Matlab/Simulink software, construct a simple simulation model of a PV battery, storage battery and bi-directional DC/DC converter, and simulate and verify the anti-interference ability and stability recovery ability of the microgrid under the situation of external disturbance. The experimental results show that the system can simulate the operation of a microgrid system.

In order to ensure the safety of financing collateral, financial institutions usually entrust third-party logistics companies to supervise the financing vehicles in stores, and the supervision cost is borne by the dealers. However, in recent years, with the increase of labor cost, the pressure on dealers’ income is increasing; and there are frequent cases of third-party supervisors and dealers colluding to sell financing vehicles without permission, It causes the loss of financial institutions’ pledge and the increase of bad debts; Orion supervises the company’s huge compensation liability risk. How to find a more economical and effective financing vehicle management and control mode to avoid personnel risk is a subject that needs in-depth discussion for financial institutions, major automobile manufacturers and dealers. This paper proposes the application of intelligent supervision mode, the use of Internet of things technology, with the help of OBD equipment, certificate key electronic supervision box, combined with the system database, to build a supply chain financial platform, realize the intelligent, real-time identification, positioning, tracking and management of vehicles, ensure 24-hour continuous monitoring, timely warning of abnormal state, alleviate regulatory loopholes, reduce the number of people For the reason of vehicle loss, theft, transfer sales and other risks. Through the questionnaire survey of three stores, more than 98% of the staff are satisfied with the intelligent supervision mode.

Porosity and permeability are important properties of porous materials, such as rocks and concrete. This paper presents the physical-mathematical modelling of a novel test, based on one previously developed by one of the authors (standardized in Switzerland, Japan and China) for measuring the air-permeability of concrete structures. In the present case, a cylindrical specimen is placed inside an air-tight cell, subjected to an initial vacuum pressure P 0, which is afterwards isolated from the pump. The rate of pressure increase (due to the extraction of air originally at atmospheric pressure Pa ) is related to the coefficient of permeability of the material whilst the final pressure attained is a function of the porosity (total amount of air extracted). The analysis assumes a unidirectional radial flow of air, which can be achieved by a special serial three-chamber vacuum cell (with pressure regulation of the external chambers) or by an air-tight sealing of the extreme faces of the cylinder. The analysis is developed under the assumption of viscous laminar flow. To account for the molecular diffusion flow, the test can be performed under vacuum (P 0 ≪ Pa) and under overpressure (P 0 ≫ Pa ), enabling the application of the Klinkenberg correction to get the intrinsic coefficient of permeability.

Power generation around the world is changing dramatically as a consequence of the demand to lower greenhouse gas releases and present a mix of power supplies. Energy storage technology is considered to be the fundamental technology to address these challenges and has great potential. This paper presents the current development and feasibilities of compressed air energy storage (CAES) and provides implications for upcoming technology advancement. The paper introduces various primary categories of CAES (Advanced Adiabatic-CAES, Liquid Air Energy Storage and Supercritical CAES). Compared with other energy storage technologies, CAES is considered a fresh and green energy storage with the distinctive superiorities of high capacity, high power rating, and long-term storage, and shortcomings of low power density, high transportation losses, and geological restriction. CAES is regarded as a promising technology that is able to be applied in renewable energy production, cogeneration, and distributed energy and microgrid systems. It’s also considered to be integrated with other technologies, such as renewable energy, gas turbine, solid oxide fuel cells, and other systems in the future.

Etching piezoelectric Scandium Aluminum Nitride (ScAlN) films containing a high concentration of Scandium with controllable feature profile angle and smooth surface is needed for next-generation Bulk Acoustic Wave (BAW) RF filter applications. This paper reports the facile etching of ScAlN with Scandium concentration of up to 15% using Reactive Ion Beam Etching (RIBE) with a very smooth surface of less than 5 nm average roughness and profile angle between 60 to 80 degrees. Recent studies show that doping AlN with a high concentration of Sc increases the piezoelectric response by five times and the bandwidth of RF filters also improved. However, etching ScAlN with a high concentration of Sc using traditional RIE and ICP based methods are extremely difficult and often results in low etch rate and rough surface. We have developed RIBE processes using a mixture of Reactive Gas and Ar with highly controllable profile angle from 60 to 80 degrees, improved etch rate (~ 36nm/min) and selectivity to photoresist mask (0.7:1), in comparison to conventional IBE. This work has positive implications in fabricating ScAlN based BAW RF filters for next-generation mobile and wireless applications.

Epoxy resin has been widely used in many fields. The improvement of friction and wear property can further expand the application range of epoxy resin. Filling modification can improve the tribological state of epoxy resin and improve the friction and wear property of epoxy resin. This paper summarizes the research of epoxy resin composite material tribology performance at the forefront of progress. The influence of different fillers on the friction and wear properties of epoxy resin composite materials was discussed from the aspects of the single filling of nano-filler, organic materials and inorganic lubricating fillers and the compound filling of inorganic or organic-inorganic fiber-filler. Many researching literature shows. The mechanical properties of epoxy resin composites are strengthened by adding filler to epoxy resin to improve the load bearing capacity of epoxy resin composites during friction. At the same time, add filler to reduce the surface of epoxy resin and the friction pair of duality between the caking property, and in the process of friction is easy to form transfer film, transfer film to isolate the direct contact of the friction surface, composite materials and the dual friction between surfaces into composite materials and transfer film, the friction between improved tribological condition between the friction pair, reduce the friction coefficient and wear rate of epoxy resin composites multiple fillers can improve the wear resistance and reduce the friction coefficient of epoxy resin composites, so that the epoxy resin composites have better tribological properties.

The goal of the paper is to interpret AMS-02 positron data. Most of the positrons come from secondary production which can fit well the data below 10 GeV. However, above 10 GeV the positron flux detected is much higher than the predictions for the secondary production. This is called ‘positron excess’ whose origin remains unknown, and interpretations including supernova remnants, pulsar wind nebulae (PWNe) or dark matter have been considered. In this paper, we investigate if PWNe can explain this ‘positron excess’ and whether a single pulsar can contribute entirely to it. To do this, we select some powerful pulsars in the ATNF Pulsar Catalogue with specific age and distances from earth and calculate their positron flux. By using a minimization package in Python to adjust the spectral slope of the PWNe and the normalization of the secondaries, we find the best fit to AMS-02 data for each of those pulsars. We can see from the result that if we want to explain the ‘positron excess’ using a single pulsar, Geminga is the best solution in the ATNF Pulsar Catalogue. Moreover, we find that except for the powerful pulsar J0633+1746 (Geminga), B1742-30 and J1741-2054, most of the pulsars we selected need an efficiency much greater than 1 to fit the data. It means that for those pulsars, one pulsar’s energy is not powerful enough to explain the data entirely. Therefore, for pulsars that are not powerful enough, adding more pulsars together provides us with a possible way to interpret this ‘positron excess’ problem.

The aim of this study is to investigate the thermoluminescence (TL) and infrared-stimulated luminescence (IRSL) properties of three types of feldspars from the districts of Solonopole and Parelhas located in the Northeast region of Brazil in order to propose a preheat procedure to minimize the anomalous fading effect in these materials. The feldspar samples were characterized by X-ray diffraction (XRD) and X-ray fluorescence spectrometry (XRF). The XRD analysis showed that the feldspar from Solonopole and one of the samples from the Parelhas district were classified as microcline (K-feldspar). The other sample from Parelhas was classified as albite (Na-feldspar) mixed with low concentration of muscovite and quartz. Studies of the fading effects in TL and IRSL signals for 30 days and preheating effects from 50 to 250°C for 10 minutes were carried out with these samples. The results show that preheating at 125°C is sufficient to avoid the 30 days fading. The TL and IRSL dose responses for 60Co gamma radiation were studied in the range of 1 to 400 Gy. The results showed a linear response in the range of 1 to 100 Gy for the two types of Parelhas feldspars and from 50 to 400 Gy for the Solonopole feldspar. The low sensitivity showed by the feldspar from Solonopole is discussed in relation to its mineralogical composition. It is concluded that the TL and IRSL sensitivities are not associated with K- and Na- types of feldspar. The results of this paper will contribute to a standardized moderate annealing treatment for retrospective dosimetry and dating.

In the construction process of box culvert form-work without tie rod, the stress state of its supporting system is of great importance. Based on a construction project for the box culvert without tie rod form-work, this paper studied the force characteristics of diagonal braces during the concrete pouring of the box culvert. The force calculation theory of the support system was analyzed and the force was analyzed using the finite element software Midas Civil. The results showed that when the distance between the connection point of the diagonal brace and the foundation was 1 m, the diagonal brace cannot provide effective support for the template, and when the distance between the connection point of the diagonal brace and the template is 2 m, 3 m, and 4 m, the diagonal brace can provide effective support. It was recommended that the diagonal brace connection point is 3 m away from the template as the optimal diagonal brace layout position. It is recommended to strengthen the area of increased local deformation of diagonal braces to a certain extent according to the calculation results of this finite element analysis to improve the safety performance of the entire structure. The research results of this paper can provide reference for follow-up similar construction problems.

Based on a large number of literatures and reports, this paper takes communication systems in lifeline engineering as an example, collects as many disaster-related communication data as possible to form a training data set, and analyzes the relationship between disaster-related telecommunications data and earthquake intensity. Then, use visual means to preprocess the collected data set. This paper uses different classification algorithms in machine learning, such as Naive Bayes, K-nearest neighbors, logistic regression and support vector machines for classification training of the formed data set. Optimize it, and finally it proposes a reference model that can be used to predict earthquake intensity. Finally, experiments show that the model has good accuracy.

The spiral cavitating vortex rope developed in the draft tube of Francis turbine under part load condition maybe causes serious pressure fluctuations and power swings, which threatens the safety and stability of the power plant operations. Many works have been performed to explore the mechanisms of it. In this paper, the runner cavitation and spiral vortex rope under part load conditions were studied to investigate the relations of runner cavitation and the spiral vortex rope. The results proved the existence of obvious interaction between them. The swirl flow at the runner outlet plays an important role in the formation of vortex rope. And the periodic procession of vortex rope in turn intensifies the uneven pressure distribution near the runner outlet and causes the asymmetric cavitation on the runner blades, which then give rise to the modification of swirl flow at the runner blades and thereby affects the characteristics of vortex rope.