RESUMO
Interlayer coupling strength dichotomizes two-dimensional (2D) materials into layered and non-layered types. Traditionally, they can be regarded as atomic layers intrinsically linked via van der Waals (vdW) forces or covalent bonds, oriented orthogonally to their growth plane. In our work, we report a material system that differentiates from layered and non-layered materials, termed quasi-layered domino-structured (QLDS) materials, effectively bridging the gap between these two typical categories. Considering the skewed structure, the force orthogonal to the 2D QLDS-GaTe growth plane constitutes a synergistic blend of vdW forces and covalent bonds, with neither of them being perpendicular to the 2D growth plane. This unique amalgamation results in a force that surpasses that in layered materials, yet is weaker than that in non-layered materials. Therefore, the lattice constant contraction along this unique orientation can be as much as 7.7%, tantalizingly close to the theoretical prediction of 10.8%. Meanwhile, this feature endows remarkable anisotropy, second harmonic generation enhancement with a staggering susceptibility of 394.3 pm V-1. These findings endow further applications arranged in nonlinear optics, sensors, and catalysis.
RESUMO
Two-dimensional (2D) transition-metal borides (TMBs) are especially expected to exhibit excellent performance in various fields among electricity, superconductivity, magnetism, mechanics, biotechnology, battery, and catalysis. However, the synthesis of ultrathin TMB single crystals with ultrahigh phase purity was deemed extremely challenging and has not been realized till date. That is because TMBs have the most kinds of crystal structures among inorganic compounds, which possess generous phase structures with similar formation energies compared with other transition-metal compounds, attributing to the metalloid and electron-deficient characteristics of boron. Herein, for the first time, we demonstrate a chemical potential-modulated strategy to realize the precise synthesis of various ultrahigh-phase-purity (approximately 100%) ultrathin TMB single crystals, and the precision in the phase formation energy can reach as low as 0.01 eV per atom. The ultrathin MoB2 single crystals exhibit an ultrahigh Young's modulus of 517 GPa compared to other 2D materials. Our work establishes a chemical potential-modulated strategy to synthesize ultrathin single crystals with ultrahigh phase purity, especially those with similar formation energies, and undoubtedly provides excellent platforms for their extensive research and applications.
RESUMO
Many litchi flowers are discarded in China every year. The litchi flower is rich in volatile compounds and exhibits strong anti-obesity activity. Litchi flower essential oil (LFEO) was extracted by the continuous phase transformation device (CPTD) independently developed by our research group to recycle the precious material resources in litchi flowers. However, its fat-reducing effect and mechanism remain unclear. Employing Caenorhabditis elegans as a model, we found that LFEO significantly reduced fat storage and triglyceride (TG) content in normal, glucose-feeding, and high-fat conditions. LFEO significantly reduced body width in worms and significantly decreased both the size and number of lipid droplets in ZXW618. LFEO treatment did not affect energy intake but increased energy consumption by enhancing the average speed of worms. Further, LFEO might balance the fat metabolism in worms by regulating the DAF-2/IIS, sbp-1/mdt-15, and nhr-49/mdt-15 pathways. Moreover, LFEO might inhibit the expression of the acs-2 gene through nhr-49 and reduce ß-oxidation activity. Our study presents new insights into the role of LFEO in alleviating fat accumulation and provides references for the large-scale production of LFEO to promote the development of the litchi circular economy.