SnO ₂ nanoparticles are synthesized using a facile method and exhibit a high response and fast response/recovery speeds towards formaldehyde.

The depletion layer and more active sites are the key factors for improving the gas sensitivity of an Fe₂O₃/ZnO sensor.

Hierarchical CuO microspheres have been successfully synthesized by a facile one-step hydrothermal method. Morphology analysis indicated that the as-obtained hierarchical CuO microspheres with diameters of ∼2.3 μm were assembled as monocrystalline nanosheets. The three-stage growth process from Cu(OH)₂ to the final hierarchical CuO microspheres was studied in detail. Moreover, the gas sensing properties of the as-obtained materials for ethanol were studied. The results reveal that the hierarchical CuO microspheres based sensors exhibit good selectivity, high sensitivity as well as rapid response (2 s) and recovery (8 s) time for ethanol, all of which are attributed to their characteristic hierarchical structures assembled with monocrystalline nanosheets.

Hyperspectral remote sensing (RS) has rapidly developed in recent years and has been widely used in the military field. This technology not only brings huge opportunities for military reconnaissance but also poses unprecedented challenges to military camouflage, severely complicating the development of plant hyperspectral camouflage materials and technology. In this review, the spectral reflectance characteristics of plants and the application of hyperspectral RS in plant RS and military operations are reviewed. The development status of bionic camouflage materials that simulate the spectral reflection characteristics of plants is analyzed. With the existing hyperspectral camouflage materials and technology, bionic camouflage technology is limited by the inability of bionic materials to accurately imitate the characteristic absorption peaks of green vegetation, low stability and durability, and the large overall material thickness, which complicate actual large-scale application. On this basis, a future development direction and a trend of plant hyperspectral bionic camouflage materials and technology are proposed.