A simple and convenient Ostwald ripening route to the morphology‐ and phase‐controlled preparation of hollow Sb2S3 microspheres is developed. The hollow spheres are clusters of smaller microspheres if orange amorphous Sb2S3 colloid is used as the precursor, whereas, if starting from the yellow precursor, the products are regular hollow spheres. By selecting appropriate experimental conditions for ripening, the phase of the hollow Sb2S3 microspheres can be controlled. Amorphous and orthorhombic hollow spheres are prepared by ripening the colloidal precursors at ambient temperature and in an autoclave, respectively. The closed shell of hollow Sb2S3 spheres can be easily eroded by hydrochloric acid to form an open structure. By the in situ reduction of adsorbed Ag+ on the surface and interior of the hollow spheres, Ag nanoparticles are introduced into them, to form functional metal–semiconductor composites, the weight content of which is controlled by regulating the concentration of the Ag+ source and the adsorption time. The composite structures composed of Ag nanoparticles and hollow Sb2S3 spheres exhibit a remarkably enhanced absorption covering the UV and visible regions of the electromagnetic spectrum. A study of the photocatalytic properties of the composite structures demonstrates that exposure to both UV and visible light enables them to induce the rapid decomposition of 2‐chlorophenol. The degradation rate increases with a larger weight content of Ag in the composite structure.
The study proposes a wavelet controller design for micro-permanent magnet synchronous drive systems. A systematic wavelet control algorithm is proposed to obtain the fast responses, good load disturbance responses and satisfactory tracking responses for time-varying commands. The wavelet control algorithm can be applied for both the speed-loop control system and the position-loop control system. A digital signal processor, TMS 320F28335, is used to execute all control algorithms. As a result, the hardware is very simple. Experimental results validate the simulated waveforms and show the correctness and feasibility of the proposed method.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.