Fractional-order electromagnetic modeling and identification for PMSM servo system.

An accurate electromagnetic model is essential for an optimal controller tuning of the high-performance servo system. This paper proposes a fractional-order electromagnetic model of a permanent magnet synchronous motor (PMSM) servo system and an identification methodology of this model. The reason why the investigated electromagnetic model should be a fractional-order one is addressed with a detailed explanation. The influence of voltage source inverter nonlinearity, which may cause system identification error, is analyzed. An improved inverter nonlinearity model and compensation method are proposed to promote the accuracy of the model parameter identification. Compared with the existing typical electromagnetic models of the PMSM servo system, the current open-loop and closed-loop experiments prove that the proposed fractional-order electromagnetic model with time delay is more accurate for the actual physical system. The effectiveness of the proposed nonlinearity modeling and compensation scheme of the inverter is also verified on an experimental PMSM servo system.

Active disturbance rejection control with fractional-order model-aided extended state observer.

Increasing the observer bandwidth of the extended state observer (ESO) can significantly enhance the disturbance rejection performance of the active disturbance rejection control (ADRC). However, a large observer bandwidth can also amplify the noise and degrade the control quality. This study proposes a novel fractional-order ADRC (FOADRC) approach. A fractional-order model-aided extended state observer (FOMESO) is designed by leveraging available plant information. Under a given observer bandwidth, the disturbance estimation performance of FOMESO is improved, while noise sensitivity is not aggravated. Additionally, FOMESO transforms a typical second-order plant into a fractional-order double-integrator model, reducing the phase lag to below 180∘. Consequently, the derivative component, which is sensitive to noise, is unnecessary in the feedback controller. Simulation and comprehensive comparisons demonstrate that the proposed FOADRC scheme outperforms the traditional ADRC in tracking, noise sensitivity, disturbance rejection, and stability. Furthermore, the proposed FOADRC approach is robust to plant parameter variations. The proposed method is validated through experiments on a permanent magnet synchronous motor speed servo system, confirming its superiority and effectiveness.

The genus Datura L. (Solanaceae): A systematic review of botany, traditional use, phytochemistry, pharmacology, and toxicology.

The genus Datura has been used as an important traditional medicine in China, as well as in other countries worldwide. This review summarizes the latest progress and perspective of the genus Datura, from the aspects of botany, traditional uses, phytochemistry, pharmacology, and toxicology. Up to May 2022, literatures were collected from online scientific databases, including Google Scholar, PubMed, SciFinder, CNKI, ACS, and Web of Science, and information was also obtained from "Flora Republicae Populairs Sinicae", Chinese Pharmacopoeia, Chinese herbal classic books, and Ph.D. and M. Sc. dissertations. Studies on chemical constituents, pharmacological activities, and toxicity are mainly focused on D. metel, D. stramonium, and D. inoxia. Furthermore, 496 compounds have been discovered from the genus Datura, including withanolides, alkaloids, flavonoids, terpenoids, phenylpropanoids, steroids, amino acids, aromatics, and aliphatics. Among them, withanolides and alkaloids are two main active constituents. Pharmacological activities of extracts and compounds have been studied from the aspects of antitumor, antiinflammation, antioxidant, antimicrobial, antispasmodic, anticoagulant, analgesic, hypoglycemic and xanthine oxidase inhibitory activities, as well as the effects on central nervous system and immune system. Modern pharmacological studies have provided more clues to elucidate the traditional usages. The toxicity of the genus Datura is noteworthy, especially the potential toxicity on organs. This review would provide a comprehensive and constructive overview for new drug development and utilization of the genus Datura.

Coupling a 3D Lithophilic Skeleton with a Fluorine-Enriched Interface to Enable Stable Lithium Metal Anode.

Lithium (Li) metal anode is known as a potential anode candidate for next-generation high-energy-density rechargeable batteries. Nevertheless, the challenge caused by the uncontrollable Li dendrites' growth and the fragile solid electrolyte interface (SEI) layer seriously hinders the commercial application of Li metal batteries. Herein, we report a fluorine-enriched nitrogen-doped hollow carbon spheres decorated carbon fibers (FNCS@CF) skeleton which effectively integrates the uniformly distributed lithophilic sites and mechanically robust LiF-enriched SEI, thus endowing the composite Li metal anode with durable and dendrite-free features. The Li nucleation barrier is greatly reduced owing to the strong lithiophilicity characteristics of pyridinic/pyrrolic nitrogen. The fluorinated hollow carbon spheres can not only provide a powerful setting for Li deposition but can also promote the in situ formation of LiF-enriched SEI. As a result, the prepared FNCS@CF skeleton demonstrates excellent electrochemical performances such as ultrahigh average Coulombic efficiency of 99.6% over 240 cycles at 3 mA h cm-2 and remarkable cyclability (1300 h) with a low deposition overpotential of 10 mV. Furthermore, a FNCS@CF-Li|NCM full cell was also assembled which exhibits a prominent cycling stability and capacity retention even under simulated practical working conditions, i.e., low negative-to-positive capacity (N/P) ratio of 1.5 and lean electrolyte of 10 uL mAh-1.

Daturanolide A-C, Three New Withanolides from Datura metel L. and Their Cytotoxic Activities.

Three new withanolides (1-3), named as daturanolide A-C, along with six known withanolides (4-9) were isolated from the flowers of Datura metel L. Their structures with absolute configurations were elucidated by a series of spectroscopic methods, electronic circular dichroism (ECD) analyses, and X-ray crystallography. All the isolates were evaluated for cytotoxicity against five human cancer cell lines (HCT116, U87-MG, NCI-H460, BGC823, and HepG2), and 6 exhibited marked cytotoxicity.