A number of marine organisms use muscle-controlled surface structures to achieve rapid changes in colour and transparency with outstanding reversibility. Inspired by these display tactics, we develop analogous deformation-controlled surface-engineering approaches via strain-dependent cracks and folds to realize the following four mechanochromic devices: (1) transparency change mechanochromism (TCM), (2) luminescent mechanochromism (LM), (3) colour alteration mechanochromism (CAM) and (4) encryption mechanochromism (EM). These devices are based on a simple bilayer system that exhibits a broad range of mechanochromic behaviours with high sensitivity and reversibility. The TCM device can reversibly switch between transparent and opaque states. The LM can emit intensive fluorescence as stretched with very high strain sensitivity. The CAM can turn fluorescence from green to yellow to orange as stretched within 20% strain. The EM device can reversibly reveal and conceal any desirable patterns.

Image sensors are increasingly being used in biodiversity monitoring, with each study generating many thousands or millions of pictures. Efficiently identifying the species captured by each image is a critical challenge for the advancement of this field. Here, we present an automated species identification method for wildlife pictures captured by remote camera traps. Our process starts with images that are cropped out of the background. We then use improved sparse coding spatial pyramid matching (ScSPM), which extracts dense SIFT descriptor and cell-structured LBP (cLBP) as the local features, that generates global feature via weighted sparse coding and max pooling using multi-scale pyramid kernel, and classifies the images by a linear support vector machine algorithm. Weighted sparse coding is used to enforce both sparsity and locality of encoding in feature space. We tested the method on a dataset with over 7,000 camera trap images of 18 species from two different field cites, and achieved an average classification accuracy of 82%. Our analysis demonstrates that the combination of SIFT and cLBP can serve as a useful technique for animal species recognition in real, complex scenarios.

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A novel high-performance gel polymer electrolyte (GPE) based on an electrospun polymer membrane of poly(vinylidene fluoride)/ poly(propylene carbonate) (PVdF/PPC) was prepared and investigated for high-performance lithium-ion battery applications. This study presents a methodology for introducing PPC into PVdF-based GPEs designed for highperformance lithium-ion batteries. SEM images and porosity measurements showed that the electrospun membrane had a uniform and highly interconnected porous structure with an average fiber diameter of 300−850 nm. Such a morphology resulted in excellent electrolyte uptake amount (500 wt %) and retention in PVdF/PPC membrane. The DSC result indicated that the PVdF crystallinity was deteriorated by the incorporation of PPC. The PVdF/PPC electrospun membrane showed significantly higher ionic conductivity (4.05 mS•cm −1 ) than that of the PVdF electrospun membrane (2.11 mS•cm −1 ) at 30 °C. The PVdF/PPC GPE was stable at a potential higher than 5.2 V (versus Li + /Li). The capacity of Li/ CGE-20/LiFePO 4 was 160, 151, 133, 119, and 102 mAh g −1 at a charge/discharge rate of 0.1, 0.2, 0.5, 1, and 2 C, respectively.

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In this work, graphene quantum dots (GQDs) with an average size of 3.9 nm were synthesized using rice husk biomass as the raw material via a facile one-step one-pot hydrothermal method. The size and morphology of the rice husk-derived GQDs were characterized by transmission electron microscopy and atomic force microscopy. The GQDs exhibit bright blue photoluminescence under 365 nm ultraviolet irradiation and can be well dispersed in water. The GQDs reach the strongest photoluminescence excitation intensity at ca. 360 nm under an emission wavelength of 466 nm, suggesting that the GQDs were oxidized with oxygenous groups attached. The quenching tests showed that the synthesized GQDs were highly and selectively sensitive toward Fe3+ ions and thus can potentially be used for Fe3+ sensing.