Based on the great advantages of an inner hollow structure and excellent solid counterpart capacity, complex hierarchical structures have been widely used as electrodes for lithium‐ion batteries. Herein, hierarchical yolk–shell Cu2O@CuO‐decorated RGO (YSRs) was designed and synthesized via a multi‐step approach. Octahedron‐like Cu2O‐decorated RGO was firstly produced, in which GO was reduced slightly while cuprous oxide was synthesized. Subsequently, the controlled oxidation of Cu2O@RGO led to the synthesis of special YSRs, which were composed of a solid Cu2O core, spur‐CuO, CuO shell, and RGO covered. As anode materials, YSRs could provide considerable capacity density. Meanwhile, the void existed between shells and solid active materials retaining the advantages of inner hollow structure. As a result, the unique architecture of the materials renders the composites with enhanced electronic and ionic diffusion kinetics, high specific capacity (~894 mAh g‐1, 0.1C), and an excellent rate capability.

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The vibration and sound signals get widely applications in fault diagnosis of rolling bearing systems, but the detection accuracy is unstable at different measuring positions. This paper puts forward a two-step vibration-sound signal fusion method, in which sound signal fusion and vibration-sound signal fusion are executed respectively. The sound signals are fused through weighting to the vibration signal to reduce the influence by measuring positions, and the phase difference is eliminated by a sliding window on the time axis. Then a second fusion between the vibration signal and sound signal is conducted after normalization and superposition, and the performance of two-step fusion is compared with the existing direct fusion. Results show that the two-step fusion provides a larger signal-to-noise ratio, and the amplitudes of characteristic frequencies are also higher. A cascaded bistable stochastic resonance system is applied in the post-processing of the fusion signal to make the signal features more clear, and it is proved that the fault detection effect has an obvious improvement after the whole process. This method provides a new approach for weak fault feature detection in vibration and sound signals, and is of great significance for the maintenance of rolling bearing systems.

First-principles calculations have been carried out for the 20-electron transition metal complexes (Cp)2TMO and their molecular wires (Cp = C5H5, C5(CH3)­H4, C5(CH3)5; TM = Cr, Mo, W). The calculation results at the BP86/def2-TZVPP level reveal that the ground state is singlet and the optimized geometries are in good agreement with the experimental values. The analysis of frontier molecular orbitals shows that two electrons in the highest occupied molecular orbital HOMO-1 are mainly localized on cyclopentadienyl and oxygen ligands. Furthermore, the nature of the TM–O bond was investigated with the energy decomposition analysis-natural orbitals for chemical valence (EDA-NOCV). The attraction term in the intrinsic interaction energies ΔE int is mainly composed of two important parts, including electrostatic interaction (about 52% of the total attractive interactions ΔE elstat + ΔE orb) and orbital interaction, which might be the major determinant of the stability of these (Cp)2TMO complexes. All of the TM–O bonds should be described as electron-sharing σ single bonds [(Cp)2TM]+–[O]− with the contribution of 53–57% of ΔE orb and two π backdonations from the occupied p orbitals of oxygen ligands into vacant π* MOs of the [(Cp)2TM]+ fragments, which are 35–40% of ΔE orb. The results of bond order and interaction energy from EDA-NOCV calculations suggest the influence of the radius of TM and methyl in the interactions between TM and O in (Cp)2TMO. Additionally, the relativistic effects slightly amplify the strength of bonding with increasing ΔE orb for the EDA-NOCV calculations on three metal complexes (C5H5)2TMO. Finally, the geometries, electronic structures, and magnetics of infinitely extended systems, [(C5H5)­TMO]∞, have also been explored. The results of the density of states (DOS) and band structure revealed that [(C5H5)­CrO]∞ and [(C5H5)­WO]∞ are semiconductors with the narrow bands, whereas [(C5H5)­MoO]∞ behaves as metal.