CsPbBr3/Cs4PbBr6 nanocomposites recently were found to yield efficient luminescence. However, the formation mechanism of the nanocomposites is unclear, and large-scale and green synthesis is still challenging. Here, we develop a self-assembly reaction to fabricate CsPbBr3/Cs4PbBr6 nanocomposites efficiently and environmentally friendly. The transmission electron microscopy clearly shows CsPbBr3 nanocrystal is embedded in Cs4PbBr6 matrix, forming a CsPbBr3/Cs4PbBr6 composite structure. In situ characterization reveals that the CsPbBr3/Cs4PbBr6 nanocomposites are formed by a two-step reaction, driven by ion concentration difference. The self-encapsulation and separation of the CsPbBr3 NCs by the host Cs4PbBr6 result in the material exhibiting a high PLQY of 83% and narrow-band emission at 517 nm with a full width at half-maximum of only 21 nm. Further, we fabricate an on-chip white light-emitting diode (LED) using the as-synthesized CsPbBr3/Cs4PbBr6 nanocomposites as a green emitter and red K2SiF6:Mn4+ phosphor on the surface of a blue LED chip. The resulting white LED exhibits a high luminous efficiency of up to 88 lm W–1 at 20 mA with an NTSC value of 131% and Rec. 2020 of 98%.

Turbulence transportation across permeable interfaces is investigated using direct numerical simulation, and the connection between the turbulent surface flow and the pore flow is explored. The porous media domain is constructed with an in-line arranged circular cylinder array. The effects of Reynolds number and porosity are also investigated by comparing cases with two Reynolds numbers ($$Re\approx 3000,6000$$ R e ≈ 3000 , 6000 ) and two porosities ($$\varphi =0.5,0.8$$ φ = 0.5 , 0.8 ). It was found that the change of porosity leads to the variation of flow motions near the interface region, which further affect turbulence transportation below the interface. The turbulent kinetic energy (TKE) budget shows that turbulent diffusion and pressure transportation work as energy sink and source alternatively, which suggests a possible route for turbulence transferring into porous region. Further analysis on the spectral TKE budget reveals the role of modes of different wavelengths. A major finding is that mean convection not only affects the distribution of TKE in spatial space, but also in scale space. The permeability of the wall also have an major impact on the occurrence ratio between blow and suction events as well as their corresponding flow structures, which can be related to the change of the Kármán constant of the mean velocity profile.

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Real-time recognition of walking-related activities is an important function that lower extremity assistive devices should possess. This article presents a real-time walking pattern recognition method for soft knee power assist wear. The recognition method employs the rotation angles of thighs and shanks as well as the knee joint angles collected by the inertial measurement units as input signals and adopts the rule-based classification algorithm to achieve the real-time recognition of three most common walking patterns, that is, level-ground walking, stair ascent, and stair descent. To evaluate the recognition performance, 18 subjects are recruited in the experiments. During the experiments, subjects wear the knee power assist wear and carry out a series of walking activities in an out-of-lab scenario. The results show that the average recognition accuracy of three walking patterns reaches 98.2%, and the average recognition delay of all transitions is slightly less than one step.

Aqueous batteries are promising candidates for large-scale energy storage due to their high safety and low cost. However, the narrow electrochemical stability window (ESW, 1.23 V) and high melting point (0 °C) of water limit the energy density and low-temperature operation of aqueous batteries. In this work, sulfolane is introduced as a co-solvent to obtain a water/sulfolane hybrid electrolyte, which participates in the solvated sheath of lithium ions, strengthens the OH bond of water, and disrupts the large-scale hydrogen bond network. Such an elaborate strategy not only expands the ESW of the hybrid electrolyte to 3.8 V, but also lowers the glass-transition temperature to −110 °C. As proof of concept, the LiMn 2 O 4 /Li 4 Ti 5 O 12 full batteries assembled by the hybrid electrolyte display high voltage (2.7 V) and excellent lowtemperature performance of 98% capacity retention from 0 to −20 °C, which can even discharge normally and illume an LED light (rated power of 0.02 W, excitation voltage of 1.8 V) at −65 °C.