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In this article, to improve the accuracy of rotor position estimation in sensorless permanent magnet synchronous motor drives, a reduced-order resonant regulator for the rotor position sliding mode observer is proposed. Since fundamental back electromotive force can be utilized to calculate the rotor position, a mathematical model for the observer is first established based on the analysis of estimation fluctuation error, where a reduced-order resonant regulator is applied to extract the fundamental back electromotive force. Then, the phase-locked loop with back electromotive force normalization is used to compute the rotor position and speed. Finally, the experimental bench of permanent magnet synchronous motor driving system is built. The experimental results verify that the proposed strategy can effectively reduce the estimation error and meanwhile improve estimation accuracy.

Fast growing Eucalyptustrees have been widely planted as cash forest. Every year, however, log harvesting leads to large amounts of Eucalyptusleaves abandoned in-situ, potentially altering the fate and transport of pollutants in the environment. In this study, the mechanism of interaction between Eucalyptusleaves -released DOM and the metal ions was systematically investigated by spectroscopic analyses, including UV-Vis, Fourier-transform infrared spectroscopy (FTIR) and three-dimensional excitation and emission fluorescence matrix (3D-EEM). The effects of infiltrated EL-released DOM on the speciation and mobility of the heavy metals in the contaminated-soil were also explored. The results showed that the interactions between EL-DOM and Cu(II) 、Pb(II) and Zn(II) in water were significant, in which, increased contents of added Cu, Pb, and Zn ions enhanced UV absorbance of EL-DOM, while addition of Mn(II) did not change the UV absorbance of EL-DOM. Compared with the functional groups in EL-DOM with UV absorbance peaking at low wavelengths, the functional groups peaking at longer wavelength were firstly affected by Cu(II), Pb(II), and Zn(II), while Mn(II) showed the opposite. Cu(II) had obvious quenching effect on all four EEM fractions (C1, C2, C3 and C4). Both Pb(II) and Zn(II) can complex with smaller and simpler humic acid-like fractions (C2), protein-like fractions (C3) and humus-like and FA-like compounds (C4). Only C2 served as organic ligands for Mn (II). Cu(II) and Zn(II) are preferentially bound to the polysaccharide C-O bond, while Pb(II) and Mn(II) are preferentially bound to the C=O bond of amide I band. Zn(II) also has the ability to bind to aromatic C-H bonds. Phenol O-H in EL-DOM was the last to be bound. EL-DOM infiltration shows little influence on Cu, Pb, and Zn mobility in soil. Infiltrated EL-DOM at low level may increase mobility of Mn(II) in soil/sediment. The results of the present study provide a scientific basis for decision-maker in the reasonable layout of Eucalyptusplanting and related pollution control.

Lead halide perovskites with good optoelectronic properties and high attenuation of high-energy radiation are great candidates for X-ray radiation detectors. Large area, dense, and thick films or wafers are a prerequisite for these applications. In this paper, a one-step heat-assisted high-pressure press method is developed to directly prepare a large (the largest has a diameter of 80 mm) and thickness- and shape-controlled phase-pure organic–inorganic hybrid CH3NH3PbI3wafer of densely packed large microcrystals from raw powder materials. Meanwhile, this method uses no solvent to achieve essentially 100% material utilization. The obtained wafers show good ambipolar carrier mobilities of ∼20 cm2V–1s–1and a μτproduct as high as 3.84 × 10–4cm2V–1. Under an X-ray source using an acceleration voltage of 40 kV, the perovskite wafer-based X-ray detector shows an X-ray sensitivity as large as 1.22 × 105μC Gyair–1cm–2under a 10 V bias, the highest reported for any perovskite material. The method provides a convenient strategy for producing large perovskite wafers with good optoelectronic properties, which will facilitate the development of large perovskite devices.