A novel bifunctional deep-eutectic solvent (DES) based on glycol (EG) and oxalic acid dihydrate (OAD) was designed for efficient and selective extraction of valuable metals from spent lithium ion batteries (LIBs) cathode active materials (LiCoO 2 or Li 14.8 Ni 1.7 Co 8.5 MnO 30.5 ) under mild conditions, realizing complete in situ separation of Li and Co/Ni/Mn. The effects of different experimental parameters on Li and Co extraction efficiencies (η Li , η Co ) were explored by orthogonal and single-factor experiments in detail. Under the optimal conditions (90 °C, 5EG:1OAD, 12 h, 16 g/L), nearly 94.4 and 94.1% of Li, as well as trace amounts of Co/Ni/Mn (<1.2%), were separately leached from LiCoO 2 and Li 14.8 Ni 1.7 Co 8.5 MnO 30.5 into the filtrate, while the oxalate dihydrates (CoC 2 O 4 •2H 2 O or (Ni, Co, Mn)C 2 O 4 •2H 2 O) with nanorod structures were achieved. The specific leaching mechanism was elucidated. Moreover, the lithium oxalate (Li 2 C 2 O 4 ) with irregular particle morphology was also obtained by evaporating the filtrate at 200 °C. The reusability of the as-prepared DES (5EG:1OAD) for the LIBs was also studied. After three cycles of DES leaching, the η Li could still reach more than 93%, while almost all Co was remained in the solid phase. This study may shed light on developing bifunctional or even multifunctional DESs to achieve highly selective extraction of metals from LIBs.

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As a kind of large flexible structure, high-rise buildings need to consider wind-resistant and anti-seismic problems for the safety of occupants and properties, especially in coastal areas. This paper proposes an infinite dimensional model and an adaptive boundary control law for an active mass damper(AMD) on this question. The dynamic model of the high-rise building is a combination of some storeys which have flexible walls and rigid floors under a series of physical conditions. Then the adaptive boundary controller is acted on an AMD which is equipped on the top floor, in order to suppress the vibration of every floor and guarantee the comfort of residents. Moreover, simulations and experiments are carried out on a two-floor flexible building to illustrate the effectiveness of the proposed control strategy.

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