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Finding water resources is a crucial objective of lunar missions. However, both hydroxyl (OH) and natural water (H2O) have been reported to be scarce on the Moon. We propose a potential method for obtaining water on the Moon through H2O formation via endogenous reactions in lunar regolith (LR), specifically through the reaction FeO/Fe2O3 + H → Fe + H2O. This process is demonstrated using LR samples brought back by the Chang’E-5 mission. FeO and Fe2O3 are lunar minerals containing Fe oxides. Hydrogen (H) retained in lunar minerals from the solar wind can be used to produce water. The results of this study reveal that 51–76 mg of H2O can be generated from 1 g of LR after melting at temperatures above 1,200 K. This amount is ∼10,000 times the naturally occurring OH and H2O on the Moon. Among the five primary minerals in LR returned by the Chang’E-5 mission, FeTiO3 ilmenite contains the highest amount of H, owing to its unique lattice structure with sub-nanometer tunnels. For the first time, in situ heating experiments using a transmission electron microscope reveal the concurrent formation of Fe crystals and H2O bubbles. Electron irradiation promotes the endogenous redox reaction, which is helpful for understanding the distribution of OH on the Moon. Our findings suggest that the hydrogen retained in LR is a significant resource for obtaining H2O on the Moon, which is helpful for establishing a scientific research station on the Moon.

Abstract Studying complex relaxation behaviors is of critical importance for understanding the nature of glasses. Here we report a Kovacs-like memory effect in glasses, manifested by non-monotonic stress relaxation during two-step high-to-low strains stimulations. During the stress relaxation process, if the strain jumps from a higher state to a lower state, the stress does not continue to decrease, but increases first and then decreases. The memory effect becomes stronger when the atomic motions become highly collective with a large activation energy, e.g. the strain in the first stage is larger, the temperature is higher, and the stimulation is longer. The physical origin of the stress memory effect is studied based on the relaxation kinetics and the in-situ synchrotron X-ray experiments. The stress memory effect is probably a universal phenomenon in different types of glasses.

Simultaneous achievement of high thermal transportation performance and superior mechanical properties in the same thermal management composite film is still a great challenge. Herein, hybrid nano and microdiamonds (hDs) were introduced for the first time to cellulose nanofibers (CNFs) and boron nitride nanosheets (BNNSs) to construct a long-range ordered "sandwiched structure" by vacuum-assisted layer-by-layer self-assembly. Benefiting from the bridging effect of diamond and the long-range ordered structure with a perfect thermally conductive path, the CNF-BNNS-hD composite film exhibits an inplane thermal conductivity of 45.76 W m-1 K-1 and through-plane thermal conductivity of 3.17 W m-1 K-1 at a filler content of 48.2 vol%. Additionally, the diamonds are fixed in the "sandwiched structure" as a support layer, and the BNNSs on both sides of the "sandwiched structure" are used for the slip layers, which significantly enhances the mechanical properties of the composite films, making the CNF-BNNS-hD composite film achieve a tensile strength of 88.6 MPa and an elongation at break of 14.7% as well as excellent insulation performance. In addition, the CNF-BNNS-hD composite film could endure 1500 folds without any fracture, demonstrating the excellent flexibility of the film. Our strategy is very effective for the fabrication of a composite film with high thermal conductivity and robust mechanical properties as well as superior electrical insulation performance. [ABSTRACT FROM AUTHOR]