Abstract: Piezoelectric materials are functional materials that can realize electromechanical coupling characteristics and are widely used in electronic information, sensors, ultrasonic transducer, nondestructive testing, and communication technology. However, the current dominant piezoelectric ceramics are lead zirconium titanate systems. These systems contain lead, which is a toxic element, and the content of lead oxide or lead tetroxide in lead-based piezoelectric ceramics is over 60%. Because of the volatile and water-soluble characteristics of lead, the production and disposal of traditional lead-based piezoelectric ceramics will result in different levels of lead pollution, which will severely harm the environment and human health. With the improvement of environmental protection and the sustainable development of human society, the harmful effects of lead-based piezoelectric ceramics have aroused increasing attention. Countries around the world have introduced legislation to ban or restrict the use of lead-based ceramics. Thus, lead-free piezoelectric ceramics have received much attention because they are environment-friendly and pollution-free. In the last decade, countries worldwide invested a large amount of funds and labor to search and develop environment-friendly lead-free piezoelectric ceramics, which can be used to replace lead-based piezoelectric ceramics in actuators, transducers, and sensors. In recent years, BiFeO3-BaTiO3 (BF-BT) lead-free solid solutions, which are considered as one of the most promising candidates for high-temperature piezoelectric applications, have received extensive attention from researchers because of their high-Curie temperature (TC) and large spontaneous polarization (Ps), as well as high piezoelectric coefficient (d33). This paper mainly reviewed recent advances in BF-BT ceramics, including the phase structure and piezoelectric property, as well as the magnetic property. In addition, the problems that need to be solved before these ceramics can be practically applied were also analyzed according to the knowledge of the authors.
Abstract: Fifth generation (5G) cellular networks are expected to achieve high data rates, reduced latency, increased spectrum efficiency, and energy efficiency. Ultra-dense networks (UDNs), a key enabling technology in 5G cellular networks, are envisioned to support the deluge of data traffic located in hotspots and at cell edges, and to enhance quality of experience of mobile users. UDNs can significantly improve the spectrum efficiency and energy efficiency to achieve sustainability of 5G. However, the deployment of a large number of small cells poses new challenges for energy efficiency. Recently, the energy efficiency of UDNs has become a prime concern in the operation and architecture design owing to environmental and economic effects. Therefore, it is significant to study the energy efficiency of UDNs. This survey provided an overview of energy-efficient wireless communications, and reviewed seminal and recent contribution to the state-of-the-art. Therefore, the definitions of energy efficiency, a key performance indicator of the UDNs, are analyzed, which is a foundation for modeling. Four theoretical models, which were often used in the modeling and optimization of energy efficiency, were discussed. These models include stochastic geometry, game theory, optimization theory, and fractional programming theory. Energy-efficient techniques of UDNs were also reviewed. These technologies include energy-efficient deployment and planning, a base station sleeping mode, user association, radio resource management, and transmission. Finally, the most relevant research challenges were addressed, including the theory of energy efficiency of UDNs, architecture of UDNs, the high energy efficiency coverage mechanism of ultra-dense small base stations, the flexible radio resource matching mechanism of UDNs, group behavior modeling of mobile users, and high energy efficiency service methods. This review of the energy-efficient coverage mechanism and flexible radio resource matching mechanism in UDNs provides design guidelines and potential solutions for analytical modeling of future wireless networks.
Abstract: With the continuous pursuit of mineral resources and the development of mineral processing technology, ore is being ground more and more finely, which has resulted in large volumes of ultrafine tailings. However, ultrafine tailings are more difficult to separate from water than coarse tailings, which also makes the safe and efficient disposal of these tailings difficult. Normally, flocculation is an essential part of solid-liquid separation to improve the settling rate, and a polymer flocculant is widely used in treating ultrafine tailings. To study the influence of flocculation conditions on the flocculation effect, ultra-flocculation theory and the UltraflocTester UFT-TFS-029 were used. The relative flocculation rate was applied to characterize the flocculation behavior of artificial ultrafine tailings under the conditions of pH 9-12, flocculant dosage fd=2 g·t-1-20 g·t-1, shear rate γ=100 s-1-2000 s-1, and solid volume fraction φ=2%-14%. The results indicate that the flocculation rate increases first and then decreases with pH, flocculant dosage, and shear rate. However, this rate decreases gradually with an increase in the solid volume fraction. The optimal flocculation conditions are: pH 11, fd=12 g·t-1, γ=500 s-1, and φ=4%. Also, to achieve the optimal flocculation rate, the dependence of the optimal shear rate on the solid volume fraction also increases with the solid volume fraction. Therefore, it is necessary to adjust the operating parameters such as pH, flocculant dosage, shear rate, and solid volume fraction to achieve optimal flocculation. A satisfactory flocculation rate of ultrafine tailings is easily achieved in a very short time using the ultra-flocculation theory, which provides a reference for the design of feed wells based on shear rate and residence time.
Abstract: Shearing is the basic factor involved in gravity thickening of paste. This work focuses on the influence of pores and throats characteristics on water drainage channel evolution, and determines the proportion of discharged water in tailings thickener bed. Pilot-scale experiment combined with computed tomography (CT) and pore network model (PNM) technology to determine the micropore structure. The maximum ball algorithm is used to analyze the evolution of pores and throats with and without shearing. The results show that the tailings underflow concentration increases from 55.8% to 58.5% under 2 r·min-1 rake shearing and the porosity decreases from 43.05% to 36.59%, the decrease rate of porosity is 15%. The pore structure can be divided into two types, i.e., "balls" and "sticks, " by the PNM technology. The quantity of "balls" and "sticks" increases by 16.5% and 22%, respectively. However, the average radius of balls decreases slightly in the range of 40-60 μm under shearing. The average radius of sticks decreases from 9.83 μm to 8.58 μm, i.e., by 12.7%. Nevertheless, the length of sticks exhibits only a slight change. The coordination number of balls increases significantly from 25.73% to 44.58% in the range of 5-10 under shearing, and the particles are in close contact. The concept of "the volume ratio of pores to balls" is proposed for the quantitative characterization of the pore structure. The volume fraction of balls decreases from 14.14% to 12.75%, the decrease rate of volume fraction is 9.83%, and volume fraction of sticks decreases from 28.91% to 23.84%, the decrease rate of volume fraction is 17.54%. The volume ratio of balls to sticks increases from 48.91% to 53.48%, and increase rate of it is 9.34%. When the volume decrease of balls is more than that of sticks, the volume ratio of balls to sticks increases. This work reveals the shearing drainage mechanism of unclassified tailings gravity thickening from the perspective of pore structure change, i.e., the drainage is mainly discharged from the throat more than the pore from the tailings thickener bed shear dewatering process.
Abstract: The presence of discontinuities and randomly distributed pores in basalt specimens greatly affects their engineering properties, such as the failure mechanism and strength. Therefore, investigating the mechanical and fracture behaviors of basalt affected by the pre-existing defects is important for underground engineering, mining engineering, foundation engineering, and rock breaking and blasting. Laboratory tests have been widely used to research the failure mechanism of rocks under different conditions. However, it is difficult to clearly show the internal or spatial crack evolution during rock failure process in laboratory tests. Recently, X-ray computerized tomography (CT) and numerical tests have been used to detect the internal microstructures of rock specimens and to study their failure mechanism and strength. In addition, tensile strength is an important mechanical property of rock material. The direct tensile test is theoretically the simplest and most effective method for understanding the tensile behavior of rock. However, it is difficult to carry out in practical condition, because the sample processing and test procedures are complicated, also the experimental process of each sample cannot be repeated and has limited results. Due to the opacity of rocks, it is difficult to examine the three-dimensional internal structures of rocks through traditional physical and numerical experiments. In the present research, a 3D numerical method was proposed for simulating porous rock failure based on CT technology, the edge detection algorithm, filtering algorithm, and 3D matrix mapping method. Direct tensile tests were carried out based on the parallel finite element method to study the effect of the porosity and pore distribution on the failure mechanism and tensile strength. The results indicate that initial cracks at the beginning of loading usually occur in pores, and then with the raising of load the initial cracks propagate along the direction perpendicular to the loading direction and eventually form macroscopic tensile cracks. The porosity and pore distribution have significant influences on the position of macroscopic tensile cracks. The acoustic emission (AE) event numbers and the accumulative AE energy are gradually decreased as the porosity increased. In addition, the brittle failure primarily determines the tensile failure mode and the presence of pores weakens the tensile strength of basalt samples.
Abstract: Since the development of the aviation industry, improving the flight performance and reducing the weight of aircrafts has always been the goal pursued by aviation designers. Therefore, it becomes increasingly important to develop a new alloy material with high hardness, high strength, and light weight. To obtain excellent mechanical properties and good corrosion resistance, a new kind of alloy material, ZL205A alloy, was developed by the Beijing Institute of Aerial Materials (BAM) in the 1960s. Owing to its favorable mechanical properties and excellent corrosion resistance, ZL205A alloy has been well applied in the aviation industry. However, this kind of Al alloy still possesses some undesirable solidification defects: shrinkage, porosities, coarsening grains, and solute segregation. Ultrasonic melt treatment (UST) provides a means to eliminate or modify these defects. In the present work, the effects of UST on ZL205A alloy were investigated for two conditions, i.e., before casting and during solidification in ambient environment. Then, the effects of ultrasonication on the as-cast microstructures and the tensile properties were accordingly characterized and analyzed. For the case in which UST was only introduced before casting (holding temperature at 750℃), degassing and the distribution of secondary phases were modified. For the case in which UST was only introduced when cooling from 750℃ for 7 min 10 s to about 650℃, grain refinement and reduced porosities were generated. When UST was continuously employed for both conditions, the above properties were further improved compared with those of ingots without ultrasonic treatment. The mechanical tensile test results show that the improvement of the ingot internal structure can improve the ingot mechanical tensile properties, which proves the correctness of the above research results. Thus, UST carried out at two different conditions induced different regulatory functions and influencing mechanisms. This study shows that the UST of ZL205A aluminum alloy in different melt states has different emphases on improving the internal structure of the ingot.
Abstract: Reduced-activation ferritic/martensitic (RAFM) steels, based on Fe-Cr alloys, have been considered to be one of the most promising candidate structural materials for future fusion reactors. Dislocation loops, as one of the most common microstructures induced by radiation, are the key factors in the deterioration of material properties. Dislocation loops with different Burgers vectors have different effects on material properties. Currently, a consensus exists suggesting that there are two kinds of dislocation loops with Burgers vectors of 1/2 〈111〉 and 〈100〉 in bcc iron-based alloys. In this study, the Burgers vectors of dislocation loops formed at the annealing temperatures of 400, 500, and 550℃ in hydrogen-ion implanted Fe-9%Cr model alloy were examined based on dislocation loop maps and dislocation loop invisibility criteria. Dislocation loop maps manifest such that under the 〈100〉 or 〈110〉 zone axes, it is easy to distinguish 1/2 〈111〉 and 〈100〉 edge dislocation loops, while under the 〈111〉 zone axis, the loops cannot be distinguished. By direct comparison between loop maps and loop images obtained through transmission electron microscope (TEM), the dislocation loops with Burgers vectors of 1/2 〈111〉 and 〈100〉, formed at different annealing temperatures, were characterized. The results of the characterization show that with increasing annealing temperature, the size of the dislocation loops increases while density decreases. Furthermore, the proportion of dislocation loops with a Burgers vector of 〈100〉 increases with rising temperature. After annealing at 400℃ and 500℃, the percentages of 〈100〉 type dislocation loops are 16.48% and 92.78% respectively, in hydrogen-ion implanted Fe-9%Cr alloy. While the temperature is raised to 550℃, all the dislocation loops are of 〈100〉 type loops. This indicates that the transition temperature range of dislocation loops in Fe-9%Cr is 400℃-500℃. Compared with pure iron, the presence of Cr element promotes the transition temperature of dislocation loops from 1/2 〈111〉 type to 〈100〉 type.
Abstract: With the development of marine industry, the performances of metal materials in marine environment have gathered much attention of scientists. Seawater, as a Cl--containing electrolyte, degrades the properties of steel structures and limits their service life due to its erosion to steel surface. The corrosion phenomena of low-alloy high-strength steels in surface seawater are well known but not sufficiently understood in deep-sea environment. The effect of hydrostatic pressure on the corrosion behavior of low-alloy steels is a focus in this aspect. However, the results from the laboratory study cannot well illustrate the ones from the field test, because some factors change simultaneously with the increase of ocean depth. Therefore, it is necessary to study the corrosion behaviors of steels in a multi-factor coupled environment. In this report, the combined effect of hydrostatic pressure and dissolved oxygen on the electrochemical behavior of low-alloy high-strength steel in 3.5% (mass fraction) NaCl solution was investigated using potentiodynamic polarization tests and scanning electron microscopy/energy-dispersive spectroscopy (SEM/EDS) measurements. The results show that the corrosion potential increases at first and then decreases with the increase of both hydrostatic pressure and dissolved oxygen. The corrosion current density exhibits a nonlinear increasing tendency with the increase of these two factors. The ideal polarization curve method was used to analyze the interaction of hydrostatic pressure and dissolved oxygen in the corrosion process. The results indicate that there is a competitive inhibition relationship between hydrostatic pressure and dissolved oxygen. With the increase of both hydrostatic pressure and dissolved oxygen, dissolved oxygen first accelerates the cathodic reaction process and inhibits the anodic reaction process. Afterwards, hydrostatic pressure starts accelerating the anodic reaction rate and inhibits the acceleration of the cathodic process caused by dissolved oxygen. The corrosion films on the steel surface significantly inhibit the acceleration to corrosion process given by the combined effect of hydrostatic pressure and dissolved oxygen. Moreover, these two combined factors encourage the growth of corrosion films and increase the number and sizes of corrosion pits forming on the steel surface.
Abstract: Based on the development trends, graphitized carbon steel has been proposed as a low-sulfur and Pb-free free-cutting steel. This steel has attracted considerable attention because of its excellent cutting performance and good cold forging performance.This study investigates graphitized carbon steel containing 0. 46% C with ferrite and graphite. In particular, its compression deformation at room temperature was studied using a universal testing machine. The load-displacement curve was fitted, the drum shape and radial elongation of the end face of the compression specimens were calculated, the surface quality and microstructure of the compression specimens were observed using optical microscopy and field-emission scanning electron microscopy, and the micro-deformation of graphite particles and the ferritic matrix in the compression specimens was statistically analyzed using Image-Pro 6. 0. The results show that the tested steel exhibits good compression deformation performance. According to the varying characteristics of the load with respect to displacement, the compression deformation process of the tested steel is divided into two stages with a displacement of 7 mm (corresponding to 58. 3% reduction) : at the compression stage with displacement ≤7. 0 mm, the load increases linearly with displacement.The value of the drum shape increases with increasing displacement, reaching a maximum value of 14. 6%, the radial elongation of the end face of the compression sample increases 34%, and the Vickers hardness at the center of the compression sample reaches its maximum value of 38. 1 HV. At the compression stage with displacement > 7. 0 mm, the load increases exponentially, the value of the drum shape gradually decreases from its maximum value, the radial elongation of the end face of compression sample increases by 83. 1%compared with that at 7. 0 mm displacement, and the Vickers hardness at the center of the compression sample reaches its minimum value of 32. 7 HV. The aforementioned experimental data show that, in the compression process with displacement ≤7. 0 mm, the three non-uniform deformation zones within the compression sample are consistent with the traditional compression model; however, in the compression process with displacement > 7. 0 mm, the center of the sample is no longer the deformation zone with the largest deformation degree in the traditional compression model. That is, the deformation degree of the three nonuniform deformation zones changes at this stage. This change leads to sharp increase in the load and to a decrease in the drum shape. In addition, during the compression deformation process, the micro-deformation degree of the graphite particles is greater than that of the ferritic matrix in the three inhomogeneous deformation zones. This is attributed to the crystal structure of graphite. In particular, graphite has a layered, planar structure in which bonding between layers occurs via weak van der Waals interactions, which enables layers of graphite to be easily separated or to slide past each other.
Abstract: Wettable cathodes are a very important part of the non-carbon electrolysis process. This study prepared Fe-TiB2/Al2O3 composite cathode materials by cold pressing and sintering using alumina sol as a binder and metal Fe as a sintering agent for aluminum electrolysis. The electrolytic performance of aluminum electrolysis was studied using a 20 A electrolysis test, and the composite cathode materials before and after the test were analyzed via EDS. The migration behavior of various elements in the electrolysis process was studied by composition analysis. The results show that Fe metal can effectively fill the gap between the aggregates during the sintering process. Hence, the sintering density of the composite cathode material can be significantly improved. In the 20 A electrolysis test, the voltage is stable, the current efficiency is 93.2%, the original aluminum quality is 99.47%, and the impurity in the aluminum liquid is 0.53%. After the electrolysis test, the aluminum liquid can moisten the cathode surface effectively. Therefore, the Fe-TiB2/Al2O3 composite is an ideal wettable cathode material. Based on the EDS analysis of the composite cathode electrolysis, the alkali metal in the liquid electrolyte permeates into the cathode material during the electrolysis process. Subsequently, alkali metals gradually penetrate into the binder phase and fill the voids that are not completely filled by alumina sol or metal sintering additives. As the electrolysis proceeds, the penetration depth of the element K is greater than that of Na. The Al generated at the cathode surface also enters the cathode through the gap of the composite material. However, owing to the gap in the cathode, the Fe metal in the cathode will also be reversely dispersed into the liquid aluminum. This study indicates that the stability of the aluminum liquid layer on the cathode surface is the foundation for efficient and stable operation of the cathode.
Abstract: The basic oxygen furnace (BOF) steelmaking process, as the predominant steelmaking method used around the world, involves very complex physical and chemical phenomena such as multi-component reactions, multi-phase fluid dynamics, and high temperature. The main task of the BOF process is tailoring the temperature and melt components to meet the requirements of high-quality steel production. With the development of intelligent steelmaking, the prediction of the end-point manganese content is an extremely important task for the BOF process, and improving the level of control regarding the end-point of BOF steelmaking can reduce production costs and enhance efficiency. In this paper, the mechanism of the BOF steelmaking process and the factors influencing the endpoint manganese content were analyzed. The control variables for predicting the end-point manganese content were also determined. To solve the problems of slow convergence, weak generalization ability, and low prediction accuracy in the prediction model established for the BP neural network, a new modeling concept based on an extreme learning machine (ELM) algorithm was proposed. By introducing regularization and improved particle swarm optimization (IPSO), a prediction model for the end-point manganese content in a converter based on improved particle swarm optimization and a regularized ELM (IPSO-RELM) was established. The paper then trained and verified the performance of these models with actual production data. A comparison of the performance of the proposed model with those of the prediction model of the BP neural network, the ELM model, and the RELM model reveals that the IPSO-RELM prediction model has the highest prediction accuracy and the best generalization performance. The hit ratio of the IPSO-RELM prediction model is 94%when the predictive errors of the model are within 0. 025%, the mean square error is 2. 18 × 10-8, and the fitting degree is 0. 72. Relative to the above three models, the IPSO-RELM prediction model may provide a more accurate prediction of the end-point manganese content and thus serves as a good reference point for actual production.
Abstract: Experiments and computational fluid dynamics (CFD) simulation were used to analyze the effects of the number and the diameter of oxygen supply ports, the flow rate and the mode of oxygen supply, and different modes of air flow (up-inlet and down-outlet on the same side, or on the different side) on the indoor oxygen enrichment characteristics and the effect of anoxic conditions in a closed buildings with or without air conditioning. Without air conditioning, the number and the diameter of oxygen supply ports, the flow rate and mode of oxygen supply, and formed oxygen-enriched regions are quite different. Using a double-45°-opposite oxygen supply ports with a diameter of 6 mm is advisable. Under the air conditioning condition, the number and the diameter of oxygen supply ports, the flow rate of oxygen supply, and the modes of air flow are different too. The formed oxygen-enriched area are all generally elliptical. It is advisable to use a single oxygen supply port with a diameter of 6 mm and an air flow mode of up-inlet and down-outlet on the different side. When the flow rate of the oxygen supply is the same, the oxygen-enriched area are formed by the wind speed of 0.85 m·s-1 is approximately 20% larger than that formed by the 1 m·s-1 wind speed. When the air supply wind speed is 0.85 m·s-1 and the oxygen supply flow rate is 1.5 m3·h-1, the oxygen-enriched area is approximately 0.96 m2, which is consistent with the area of the single-person activity. It is suitable as the basic oxygen-enriched supply for the single-person under air conditioning conditions where are lack of oxygen.
Abstract: As induction motors are the control core in variable-frequency speed-regulating systems, their efficient operation in industrial production processes needs to be ensured. To realize this, the accuracy and security of control commands and equipment parameters have been the priorities for industrial security protection research. This study aims to investigate the intrusion detection techniques of the AC-DC-AC variable-frequency vector control system for induction motors under EtherCAT industrial bus. First, the EtherCAT bus protocol is deeply analyzed, and combined with the EtherCAT industrial bus common protocol vulnerabilities that have been discovered so far, the key characteristics of the protocol data packets are extracted, and the EtherCAT bus protocol intrusion detection rule base is constructed. A three-dimensional pointer linked list tree is used as the retrieval data structure for the EtherCAT bus protocol rule base. Second, model parameters are simulated and calculated based on the physical model of the AC-DC-AC inverter vector control system of the induction motor. Then a least-squares support vector machine (LSSVM) with the characteristics of vector control model intrusion is constructed on the basis of the simulation results, and the parameters of LSSVM classifier are optimized using the chaotic particle swarm optimization (CPSO) algorithm, both of which constitute the CPSO-LSSVM intrusion detection classification algorithm. After the anomaly data packets are classified, they will be transferred to the Suricata intrusion detection engine for precise rule matching. Finally, a physical experiment environment is built for the intrusion detection system. The simulation results of the AC-DC-AC variable-frequency vector control model in this paper show good dynamic performance, which is similar to the trend of waveform change on actual vector control system parameters. The effectiveness of the intrusion detection system is verified by extracting part of the KDD Cup99 test dataset to implement the behaviors of attacks, such as the denial of service (DOS), remote-to-local (R2L), user-to-root (U2R), and Probing attacks on the intrusion detection system.
Abstract: For sensorless force control of a robot such as by drag-teaching and collision detection, the control accuracy depends on the accuracy of the robot dynamics model. The error of the robot dynamics model comes from two aspects, modeling and identification errors and from unmodeled dynamics. Among the unmodeled dynamics, one of the important sources of unmodeled dynamic is the friction inside the robot reducer. When the reducer rotates, there is mutual extrusion and friction between the internal components of the reducer. This kind of friction will change as the gear meshing state transforms, resulting in the phenomenon of wave friction torque. A remarkable feature of wave friction torque is that it has a periodic relationship with the joint location and it is often modeled by the Fourier series function. Wave friction torque is obvious when the rotational speed of the joint is low and decreases with the increase in rotational speed. In order to improve the accuracy of the robot dynamics model, the wave friction torque needs to be modeled and eliminated. Aiming at the wave friction of the robot harmonic joint during the rotation process, a modeling method based on a Fourier series function and BP neural network was proposed, the dynamic model of the robot was optimized, and the calculation error of the joint torque caused by the wave friction was corrected. By studying the variation characteristics of the wave friction of the harmonic reducer joint under different influencing factors, the combination of the Fourier series and BP neural network was used to model the wave friction. By adding the Fourier series function as the auxiliary input of the BP neural network, the difficulty of fitting the torque error curve due to the presence of high frequency periodic fluctuations was overcome. The neural network was trained in the off-line environment to complete the modeling of the wave friction, and then to improve the dynamic model of the robot and correct the wave friction. The experimental results show that the improved dynamic model can effectively predict the wave friction of the harmonic reducer joint and keep the corrected torque error within the range of[-0.5, 0.5] N·m, and the variance is 0.1659 N2·m2, which is 24.23% before the correction.
Abstract: In applied structural control technology, base-isolated technology has become popular due to its advantage of simple shock absorption, stable performance, and reasonable cost. Currently, base isolation is extensively applied worldwide, and its role in mitigating the seismic response of structures continues to grow. Moreover, it has been proven effective in decreasing seismic response of structures under recent strong earthquakes. However, the displacement at the isolation layer is sometimes large under strong earthquakes, which will decrease the safety of the structure and perhaps lead to the failure of the isolation layer. Therefore, in this study, the base-isolated structure with roller bearings is taken to investigate the seismic response control of structures, and the active control devices are added in the isolation layer of the isolated structure to decrease the seismic displacement at the isolation layer, so that a smart-isolated structure is formed. Nonsmooth control algorithm is introduced in the smart-isolated structure. Based on the feedback of the velocity and displacement of the isolation layer, nonsmooth control algorithm is proposed for designing the smart-isolated structure. Moreover, according to Lyapunov stable theory, the global finite time stability of intelligent control closed-loop system under nonsmooth control is deduced. A six-layer isolated structure with roller bearings is used as an example, and a simulation analysis of seismic response control is performed based on the nonsmooth active control algorithm and linear quadratic Gaussian (LQG) active control algorithm. The results show that the smart-isolated technology can effectively control seismic displacement at the isolation layer, and compared with the passive isolated technology, the superstructure seismic response is significantly decreased. Meanwhile, the results demonstrate that compared with the LQG control algorithm, the nonsmooth control algorithm has a better control effect and can implement feedback control for base-isolated structures by using fewer feedbacks. Furthermore, the nonsmooth control algorithm has great stability.
Monthly, started in 1955 Supervising institution：Ministry of Education Sponsoring Institution：University of Science and Technology Beijing Editorial office：Editorial Department of Chinese Journal of Engineering Publisher：Science Press Chairperson：Ren-shu Yang Editor-in-Chief：Ai-xiang Wu ISSN 2095-9389CN 2095-9389
