Thermal insulation under extreme conditions requires materials that can withstand complex thermomechanical stress and retain excellent thermal insulation properties at temperatures exceeding 1,000 degrees Celsius1–3. Ceramic aerogels are attractive thermal insulating materials; however, at very high temperatures, they often show considerably increased thermal conductivity and limited thermomechanical stability that can lead to catastrophic failure4–6. Here we report a multiscale design of hypocrystalline zircon nanofibrous aerogels with a zig-zag architecture that leads to exceptional thermomechanical stability and ultralow thermal conductivity at high temperatures. The aerogels show a near-zero Poisson’s ratio (3.3 × 10−4) and a near-zero thermal expansion coefficient (1.2 × 10−7 per degree Celsius), which ensures excellent structural flexibility and thermomechanical properties. They show high thermal stability with ultralow strength degradation (less than 1 per cent) after sharp thermal shocks, and a high working temperature (up to 1,300 degrees Celsius). By deliberately entrapping residue carbon species in the constituent hypocrystalline zircon fibres, we substantially reduce the thermal radiation heat transfer and achieve one of the lowest high-temperature thermal conductivities among ceramic aerogels so far—104 milliwatts per metre per kelvin at 1,000 degrees Celsius. The combined thermomechanical and thermal insulating properties offer an attractive material system for robust thermal insulation under extreme conditions.

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A high-sensitivity and high-spatial-resolution distributed acoustic sensor based on phase-sensitive optical frequency domain reflectometry ( Φ -OFDR) is proposed. The vibration information is retrieved from the phase change of the complex Rayleigh backscattering. Inner-pulse division and rotating-vector-sum methods are employed to overcome the fading problem and to suppress the crosstalk along the fiber. For the first time, to the best of our knowledge, the waveforms of two simultaneous kilohertz-level vibrations along a 950 m fiber are recovered thanks to the enhanced crosstalk suppression ratio. The spatial resolution of 12 cm and strain resolution of 1 n ε / H z are experimentally achieved.

There exist various forms of crystalline silica in nature, 1 and silica is a commonly used fundamental constituent of glass. Many studies have been conducted on the properties of each type of crystal structure of silica and silica glass using experiments 2,3 and simulations. [4][5][6] Using varying heat treatment temperatures and suitable inducers or templates, silica of different degrees of crystallinity can be produced. [7][8][9] However, there is a lack of systematic research on partially ordered silica states, namely silica systems in between ordered and disordered states, due to their low probability of appearance in both experiments and simulations.Melting and nucleation are two primary approaches to the generation of silica structures between crystal and glassy phases. However, due to the high energy barrier

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Porous carbon materials have exhibited many superior characteristics with extensive applications. To adequately exert their advantages at macroscale, the mechanical property plays a critical role to ensure the structural stability and functionality. Porous carbon monoliths overcome brittleness by endowing compressive superelasticity but are still plagued by poor toughness, easily suffering from the tensile, bending, or torsional fracture. Here, inspired by the biostructure of succulent plants, graphene aerogel is used to mimic the hydrenchyma tissue, carbon nanotube aerogel film as the epidermis, and graphene oxide ethanol solution as the hemicellulose binder to make ultraflexible carbon aerogels (UCAGs), addressing the critical and bottleneck issue between mechanics and functionality. The UCAGs feature a sequence of robust mechanical properties simultaneously, including compressive strain up to 99.5%, tensile strength up to 460 kPa, bending and torsional angle up to 180°. This ultraflexible aerogel is exploited for large‐deformable, and high‐sensitive strain sensor with extended working temperature (−196 to 400 °C), as well as lightweight thermal regulator with record‐high switch ratio (500:1). The high‐performance structures of this type establish a set of fundamental considerations in structural design of inorganic aerogels for a wide spectrum of applications.

Enhanced sampling molecular dynamics (MD) simulations have been extensively used in the phase transition study of simple crystalline materials, such as aluminum, silica, and ice. However, MD simulation of the crystallization process for complex crystalline materials still faces a formidable challenge due to their multicomponent induced multiphase problem. Here, we realize the ab initio accuracy MD crystallization simulations of complex ceramics by using anisotropic collective variables (CVs) and machine learning (ML) potential. The anisotropic X-ray diffraction intensity CVs provide precise identification of complex crystal structures with detailed crystallography information, while the ML potential makes it feasible to further perform enhanced sampling simulations with ab initio accuracy. We verify the universality and accuracy of this method through complex ceramics with three kinds of representative structures, i.e., Ti 3 SiC 2 for the MAX structure, zircon for the mineral structure, and lead zirconate titanate for the perovskite structure. It demonstrates exceptional efficiency and ab initio quality in achieving crystallization and generating free energy surfaces of all these ceramics, facilitating the analysis and design of complex crystalline materials.