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This study proposes a modified energy-saving skyhook consisting of active control, energy regeneration, and switch. The modified skyhook coordinates the contradiction between dynamic performance and energy consumption of electromagnetic active suspension. The control principle is analyzed, the switch condition between active control and energy recovery is provided, and the switch control system is designed for simulation. Results demonstrate that the presented strategy can coordinate the dynamic performance and energy consumption effectively. The realization structure, namely, a hybrid electromagnetic actuator, is then designed to satisfy the control requirements. It integrates a linear motor and a hydraulic damper. The linear motor is used for active control or energy regeneration, while the hydraulic damper is used to guarantee basic dynamic performance. The structural dimension of hybrid electromagnetic actuator is optimized to increase air gap flux density with the volume and weight limitation. A prototype is fabricated, and a bench test is conducted. Results show that the structure can satisfy the control requirements. Some errors within a reasonable range are also observed between the test and the simulation because the simulation model is prepared under ideal conditions.

A highly fluorescent nitrogen and sulfur codoped carbon nanoparticles (N,S-CNP) sample was obtained by microwave-assisted pyrolysis of citric acid and L-cysteine. After being purified by dialysis, the complexity and chemical composition of N,S-CNP were evaluated by ultra-performance liquid chromatography coupled with mass spectrometry (UPLC-MS) as well as by UPLC coupled with ultraviolet (UV) absorption and fluorescence detection (UPLC-UV/FLD) methods. By using the high-resolution UPLC separation, the N,S-CNP were well fractionated into six fractions within 3.5 min. Based on high-accuracy MS and tandem (MS/MS) analyses, the N,S-CNP species were revealed to display various chemical formulas, including (C12H16N2O7S2) n , (C9H13NO8S) n , (C18H20N2O14S2) n , (C18H20N2O12S2) n , (C9H11NO5S) n , and (C9H11NO7S) n . More importantly, our study disclosed unambiguously for the first time that the N,S-CNP species exist as supramolecular clusters with their individual monomer units linked together through noncovalent bonding forces. By using UPLC-UV/FLD analysis, the spectral characteristics of each N,S-CNP species were revealed. Each individual CNP species possesses its unique absorption and PL properties with absorption bands that are redshifted, whereas its emission bands are blueshifted with its elution order. This work highlights the merit of UPLC-MS together with UPLC-UV/FLD to investigate the chemical composition and the spectral properties of each individual N,S-CNP species. It is anticipated that our proposed methodology will open up a new venue in optimizing experimental conditions for producing specific N,S-CNP species of desired composition. Graphical Abstract Carbon nanoparticles synthesized by microwave-assisted pyrolysis of citric acid and L-cysteine exist as supramolecular clusters with their individual monomer units linked together by noncovalent interactions.

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Cysteine reacts with reactive carbonyls to form thioprolines, which have been demonstrated to possess various pharmaceutical properties. Therefore, thioproline formation is considered as a major detoxification pathway for carcinogenic reactive carbonyls. In this study, we report the initial identification of thiazolidine-4-carboxylic acid (1) and 2-methylthiazolidine-4-carboxylic acid (2), two very common thioprolines, formed by reacting formaldehyde and acetaldehyde with cysteine in grape wine samples. We have developed an isotope dilution-liquid chromatography-tandem mass spectrometry method featuring high sensitivity (limit of detection of ≤1.5 ng/mL) and selectivity to quantitate compounds 1 and 2. The method after validated to be highly accurate (recovery of ≥92%) and precise [intraday relative standard deviation (RSD) of ≤4.1% and interday RSD of ≤9.7%] was applied to determine the varying compound 1 and 2 contents in grape wine samples. Results revealed the grape type and storage duration-dependent formation of thioprolines in grape wines. Overall, the results are expected to facilitate compound-dependent investigations of the health benefits of grape wine, and our findings could be adopted to predict the age of grape wine.

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A type of hybrid electromagnetic suspension is proposed in this study to improve the reliability of a conventional active electromagnetic suspension. A motor with the proposed hybrid electromagnetic suspension linear can regenerate the vibration energy; the coordination relationship between the energy regeneration and the vibration isolation of the hybrid electromagnetic suspension is studied. A dynamic model is established, and a modified skyhook control strategy is designed. A passive energy regeneration control system and an active control system are developed. The effect of the damping on the energy regeneration and the vibration isolation is discussed. The best damping, which can consider the energy regeneration and the vibration isolation simultaneously, is determined. Comparative simulations of a passive suspension, a hybrid electromagnetic suspension and an active electromagnetic suspension are carried out, and the results verify the effectiveness of the control strategy. Finally, an energy regeneration experiment and an isolation comparative experiment of a quarter-suspension are conducted. The findings show that the hybrid electromagnetic suspension with a modified skyhook control strategy can efficiently facilitate coordination between the energy regeneration and the vibration isolation.