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This research aimed to explore the influence of fiber laying angles on the bending resistance properties of carbon fiber/foam sandwich structural composites. Four kinds of composites with the following laying angles: [0°]8, [0°/45°/90°/-45°]s, [0°/90°]4and [45°/-45°]4were prepared and tested in three-point bending experiments. The results obtained showed that the bending resistance performance was the best when the laying angle was [0°]8, while it was the worst when the laying angle was [45°/-45°]4. Besides, it was found that the tensile performance was the best when the fibers were arranged in the 0° direction when the strength utilisation rate was the highest. In addition, by observing the failure morphologies of the composites, the delamination and foam cracking were found in the four groups of composites. In contrast, the phenomenon of significant fracture was found on composites with a laying angle of [45°/-45°]4only, indicating it had a poor bending resistance performance.

Developing low Pt or non-precious metal catalysts for oxygen reduction reaction (ORR) has becoming necessary in recent years. Herein, PtM alloy anchored on nitrogen-doped carbon (PtM/NC, M=Fe, Co) catalyst with ultralow Pt loading (∼1 wt%) is prepared from the simple two-process pyrolysis, namely from C to M-NC then to PtM/NC. The as-prepared PtM/NC (M=Fe, Co) shows an excellent ORR catalytic performance with the peak potential and half-wave potential of 0.901 and 0.870 V for PtFe/NC, 0.868 and 0.845 V for Pt3Co/NC. The ORR on PtM/NC (M=Fe, Co) is a mainly direct 4-electron reaction pathway (3.75–3.90) in alkaline solution. Moreover, they possess good methanol tolerance and stability. Synergistic effect of Pt and M together with N species result in the excellent ORR catalytic activity of PtM/NC (M=Fe, Co). The negative shift of Pt binding energy caused by both lattice contraction and electron orbital coupling from M is beneficial for reducing the d-band center of Pt, weakening the oxygen binding energy and enhancing the ORR intrinsic activity of Pt. The strong interactions between NC and PtM alloy are beneficial for anchoring PtM nanoparticles, promoting the stability of catalyst. This work provides a new strategy for preparing ultralow Pt loading catalysts.

Synthetic fibers account for about half of all fiber usage, with applications in every textile field. The phenomenon of fiber composition not matching the label harms consumer interests and impedes market development. Hyperspectral imaging technology as a potential technique can be utilized to discriminate mass synthetic fibers rapidly and nondestructively and achieves the functions that traditional Fourier transform infrared instruments do not have. On the basis of investigating the impact of dope-dyeing and wrapping processes on spectra, the spectral features (from 900 to 2500 nm) of six categories of synthetic fibers were extracted with a hyperspectral imaging system. A principal component analysis-linear discriminant analysis model was developed to discriminate the chemical content of fibers in different colors and structures, which showed 100% discrimination accuracy. Results demonstrated the feasibility of a hyperspectral imaging system in synthetic fiber discrimination. Therefore, this method offers a more convenient alternative for textile industry on-site discrimination.

ZnO is one of the most popular materials in UV photodetectors, but its low switching and long attenuation time seriously hinder its practical application. In this work, the performance of PZT/ZnO planar photodetectors is optimized by using the ferroelectric polarization of PZT thin films. The results show that the residual polarization field of PZT affects the electron arrangement in ZnO film, making ZnO in a depleted state, reducing the dark current of resulted photodetectors, and influencing the carrier life. By inhibiting recombination, the photocurrent is increased, and the switching ratio of the ZnO photodetector is increased by 5 times, and more importantly, the optical responsivity increases by 7 times to 1.015 A/W. This work provides a simple and feasible method for ferroelectric polarization to control the performance of two-dimensional material photodetectors.