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Large-scale syntheses of uniform AgCl nanocubes and nanospheres with sub-100 nm size have been achieved by the reaction of AgNO 3 and CCl 4 in a solvothermal system with polyvinylpyrrolidone as a capping agent. The reaction time and temperature have been proved to be the key factors for the morphological evolution of the AgCl nanocrystals. In addition, an interesting AgCl micro-tetrahedron structure can be obtained with dichloroethane instead of CCl 4 as the chlorine source. The synthesized products are characterized by X-ray diffraction, scanning electron microscopy, UV–vis spectroscopy, and X-ray photoelectron spectroscopy. The growth mechanism of the AgCl crystals is proposed. The AgCl products can be converted to plasmonic Ag/AgCl photocatalysts under UV-light irradiation, which exhibit excellent photocatalytic activity for the degradation of the organic contaminant of Rhodamine B.

Grouted splice sleeve (GSS) connectors are mainly used in precast concrete structures. However, errors in manual operation during construction cause grouted defects in the GSS connector, which can lead to a negative effect on the overall mechanical properties of the structures. Owing to the complex structure of precast concrete members with a GSS connector, it is difficult to detect grouted defects effectively using traditional ultrasonic parameters. In this paper, a wavelet packet analysis algorithm was developed to effectively detect grouted defects using the ultrasonic method, and a verified experiment was carried out. Laboratory detection was performed on the concrete specimens with a GSS connector before grouting, in which the grouted defects were mimicked with five sizes in five GSS connectors of each specimen group. A simple and convenient ultrasonic detection system was developed, and the specimens were detected. According to the proposed grouted defect index, the results demonstrated that when the grouted defects reached certain sizes, the proposed method could detect the grouted defects effectively. The proposed method is effective and easy to implement at a construction site with simple instruments, and so provides an innovative method for grouted defects detection of precast concrete members.

Lithium–sulfur (Li–S) batteries are promising energy storage systems owing to their high theoretical energy density and low costs due to the abundant reserves of sulfur. However, the easy dissolution of intermediate polysulfides (Li2Sx, 4 < x ≤ 8) and insulating nature of sulfur have hindered their commercialization. Herein, we develop a novel confinement approach by using porous hollow carbon nanospheres (HCNs) embedded with well-dispersed cobalt monoxide (CoO) nanocrystals (CoO/HCN), which can effectively combine the advantages of physical entrapment and chemical binding interactions of sulfur species. When used as a sulfur host material, the CoO/HCN–S composite cathode with 1.4 mg cm−2 sulfur exhibits excellent electrochemical performance with high discharge capacity (996 mA h g−1 after 200 cycles at 0.2C), great rate capability (620 mA h g−1 at 5.0C) and superior cycle stability (629 mA h g−1 after 1000 cycles at 1.0C with a capacity decay of only 0.033% per cycle and 482 mA h g−1 after 1000 cycles at 2.0C with a capacity decay of only 0.043% per cycle). Furthermore, a high and stable reversible capacity of 640 mA h g−1 after cycling for 250 cycles is achieved with a higher sulfur mass loading (3.6 mg cm−2).

High-rise buildings with an active mass damper/driver (AMD) system generally use a simplified mathematical model. The result leads to parametric uncertainties including the stiffness and mass variations exist, and the accuracy of its controller is seriously affected. In view of the above uncertainties, based on a Lyapunov stability theory and linear matrix inequality (LMI) approach, a state feedback controller based on the guaranteed cost control (GCC) algorithm is proposed in this paper. A ten-storey frame with an AMD system is taken as a numerical example, and its control effect and AMD parameters are viewed as the control indexes. The performance of the proposed robust controller is compared with a conventional controller based on the classical LQR algorithm. The analysis results show that the new controller effectively suppresses the dynamic responses of high-rise buildings with parametric uncertainties and keeps the AMD parameters stable. Finally, a four-storey steel experimental frame with an AMD system is used to verify the correctness of the conclusions.

Active mass damper/driver (AMD) control system has been proposed as an effective tool for high-rise buildings to resist strong dynamic loads. However, such disadvantage as time-varying delay in AMD control systems impedes their application in practices. Time-varying delay, which has an effect on the performance and stability of single-degree-of-freedom (SDOF) and multi-degree-of-freedom (MDOF) systems, is considered in the paper. In addition, a new time-delay compensation controller based on regional pole-assignment method is presented. To verify its effectiveness, the proposed method is applied to a numerical example of a ten-storey frame and an experiment of a single span four-storey steel frame. Both numerical and experimental results demonstrate that the proposed method can enhance the performances of an AMD control system with time-varying delays.

Active mass damper (AMD) control system is proposed for high-rise buildings to resist a strong wind. However, negative influence of noise in sensors impedes the application of AMD systems in practice. To reduce the adverse influence of noise on AMD systems, a Kalman filter and a linear matrix inequality- (LMI-) based filter are designed. Firstly, a ten-year return period fluctuating wind load is simulated by mixed autoregressive-moving average (MARMA) method, and its reliability is tested by wind speed power spectrum and correlation analysis. Secondly, a designed state observer with different filters uses wind-induced acceleration responses of a high-rise building as the feedback signal that includes noise to calculate control force in this paper. Finally, these methods are applied to a numerical example of a high-rise building and an experiment of a single span four-storey steel frame. Both numerical and experimental results are presented to verify that both Kalman filter and LMI-based filter can effectively suppress noise, but only the latter can guarantee the stability of AMD parameters.

Time-delays of control force calculation, data acquisition, and actuator response will degrade the performance of Active Mass Damper (AMD) control systems. To reduce the influence, model reduction method is used to deal with the original controlled structure. However, during the procedure, the related hierarchy information of small eigenvalues will be directly discorded. As a result, the reduced-order model ignores the information of high-order mode, which will reduce the design accuracy of an AMD control system. In this paper, a new reduced-order controller based on the improved Balanced Truncation (BT) method is designed to reduce the calculation time and to retain the abandoned high-order modal information. It includes high-order natural frequency, damping ratio, and vibration modal information of the original structure. Then, a control gain design method based on Guaranteed Cost Control (GCC) algorithm is presented to eliminate the adverse effects of data acquisition and actuator response time-delays in the design process of the reduced-order controller. To verify its effectiveness, the proposed methodology is applied to a numerical example of a ten-storey frame and an experiment of a single-span four-storey steel frame. Both numerical and experimental results demonstrate that the reduced-order controller with GCC algorithm has an excellent control effect; meanwhile it can compensate time-delays effectively.

Prussian blue analogue Zn3[Fe(CN)6]2⋅xH2O (Zn-PBA) micro-/nanocrystals with well-defined spherical, cubic and polyhedral morphologies have been successfully synthesized by a simple room-temperature solution method. The morphologies and sizes of the micro-/nanocrystals can be easily tuned by HCl dosage and polymer additive. The as-prepared products are characterized by X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis and Brunauer Emmet Teller adsorption-desorption analysis. The possible formation mechanism for these Zn-PBA micro-/nanocrystals is then proposed. In addtion, adsorption performances of these micro-/nanocrystals toward organic dyes are systematically investigated. It is demonstrated that they exhibit strong adsorption selectivity to methylene blue (MB) with an extraordinary adsorption capacity as high as 1.016gg(-1) due to the proper pore size and large specific surface area (643.2m(2)g(-1)) of the product as well as the strong electrostatic interaction between MB molecules and Zn-PBA particles. It is found that the morphology and size of the micro-/nanocrystals have an important effect on their adsorption performance. Moreover, the adsorbed MB dye can be well released in some organic solvents such as ethanol and trichloromethane. The facile morphology-controlled synthesis and excellent adsorption property afford the materials promising application in adsorption related fields.

A control-structure interaction (CSI) effect commonly exists between an active mass damper/driver (AMD) system with a DC motor and a controlled building. Additionally, its higher-order component leads to the fact that the actual control force acts behind its theoretical time; i.e., time delay. In this paper, the main influencing factors of a higher-order CSI effect are analyzed, including the input frequency of the control voltage, the structural parametric uncertainties, and the control gains. In addition, a new time-delay compensation controller based on a guaranteed cost control (GCC) algorithm is designed, to consider the higher-order CSI effect for multi-level steel frame structures. Experiments on a typical four-storey frame are conducted, to verify the performances of the proposed method. The results show that the proposed controller has an excellent control effect and stable control parameters, even under the situation of large parametric uncertainties and long time-varying delays.