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Ceramic aerogels are promising lightweight and high-efficient thermal insulators for applications in buildings, industry, and aerospace vehicles but are usually limited by their brittleness and structural collapse at high temperatures. In recent years, fabricating nanostructure-based ultralight materials has been proved to be an effective way to realize the resilience of ceramic aerogels. However, the randomly distributed macroscale pores in these architectures usually lead to low stiffness and reduced thermal insulation performance. Here, to overcome these obstacles, a SiC@SiO2 nanowire aerogel with a nanowire-assembled anisotropic and hierarchical microstructure was prepared by using directional freeze casting and subsequent heat treatment. The aerogel exhibits an ultralow thermal conductivity of ~14 mW/m·K, an exceptional high stiffness (a specific modulus of ~24.7 kN·m/kg), and excellent thermal and chemical stabilities even under heating at 1200°C by a butane blow torch, which makes it an ideal thermally superinsulating material for applications under extreme conditions.

Agaricus bisporus, belonging to the genus Agaricus and the family Agaricaceae, is a popular commercially cultivated mushroom with rich nutritional and medical values. Cultivation of A. bisporus requires superior cultivars. Understanding the differences between wild and cultivated accession at the genetic level is crucial for mining loci and genes associated with cultivation-related traits, informing future breeding directions. Additionally, the identification of loci and genes associated with important agronomic traits (e.g., yield and quality) facilitates mushroom molecular breeding. In this study, we conducted sequencing of 200 strains of A. bisporus and analyzed genomic variations. Population structure and genetic relationships were investigated for 200 strains. Selection signs and genes were also obtained after selection sweep analysis. Thirteen candidate genes in the selective elimination regions had significantly different expression patterns at the fruit body stage. Moreover, six genes were identified for the esterase isozyme type through a combination of GWAS and RNA data. This study provides insight into environmental adaptation at the genetic base, providing valuable genetic resources for button mushroom molecular breeding to improve environmental adaptation, quality, or yield. [ABSTRACT FROM AUTHOR]

It is very important to detect fault and extract fault features of mechanical systems at an early stage, because the above two steps promise normal operation of mechanical systems. However, they are also very challenging. In this context, this article has put forward improved particle swarm optimization-based adaptive multiresolution dynamic mode decomposition of rolling bearing (IPSO-AMDMD). Multiresolution dynamic mode decomposition (MRDMD) is used to decompose signals of rolling bearing at the early stage, multiscale fuzzy entropy (MFE) is employed to divide low-rank components and sparse components. In order to make up for the shortcomings of the above two methods, namely truncated rank of MRDMD and inaccurate selection in threshold of MFE, this paper has proposed a new fitness function, which is called synthetic envelope kurtosis characteristic energy difference ratio, and adopted the improved particle swarm optimization algorithm (IPSO) to select the optimal parameters adaptively. With these two steps, signals can be decomposed perfectly. Finally, reconstructed signals, which are obtained through the combination of signals from each layer according to a certain weight, go through DMD again, thus getting the final recovered signal. Through simulation experiment and in-field experiment, it has proved that IPSO-AMDMD is viable and sound in accurately extracting features from fault signals. [ABSTRACT FROM AUTHOR]

The design of multifunctional materials with good thermophysical and electromagnetic shielding properties is desirable to overcome overheating and electromagnetic interference (EMI) in electronic devices. In this study, three‐dimensional (3D) continuous SiC skeleton‐reinforced highly oriented graphite flake (GF@SiC) composites were fabricated by combining molten salt synthesis, heat treatment, and spark plasma sintering. When the SiC content was higher than 9 vol.%, a 3D continuous SiC skeleton was formed, which effectively constrained the cross‐plane thermal expansion of the GF@SiC composites. Highly oriented GFs endowed the composites with good thermal conductivity (TC) along the basal plane and effective EMI shielding in the X‐band. The composites with SiC concentrations of 9 vol.% exhibited an optimal comprehensive performance with a high TC of 322 W/m/K in the basal plane direction, a low thermal expansion value of 10.5 × 10−6/K in the through‐plane direction, and EMI shielding effectiveness of 36 dB. Our strategy provides a promising and practical approach for realizing graphite‐based composites to meet the current demands for electronic devices. [ABSTRACT FROM AUTHOR]

In order to reveal the ignition characteristics and explosion propagation characteristics of coal dust, a kind of coal dust cloud is studied through the experiment and numerical simulation in confined space. The result indicated that the particle size of coal dust has a significant impact on the ignition characteristics of coal dust cloud. CFD theory is used to simulate the explosion propagation characteristics in the straight and bifurcated pipelines. It is found that the flame propagation simulation result is consistent with the experimental result. In the bifurcated pipeline, from the time of 0.2 s to 0.8 s after the explosion, the flame propagates through the bifurcated pipeline. It also revealed that the flame propagation intensity of coal dust explosion in the bifurcated pipeline is affected by the structure of the pipeline, which provides a reference for the study of the propagation characteristics of coal dust explosion. [ABSTRACT FROM AUTHOR]

Developing tunable and highly efficient electromagnetic wave (EMW) absorbers with low density is crucial for the development of wireless telecommunications devices in extreme conditions. SiC ceramic has received much attention because of its dielectric tenability, low density, and chemical stability. However, the present SiC‐based materials usually show limited EMW absorbing performance than they are expected. Herein, an ultralight and resilient bicontinuous Si3N4/SiC network (8 mg cm−3) composed of EMW‐transparent Si3N4 microbelts and EMW‐absorption SiC nanowires is designed and prepared to achieve improved impedance matching and EMW attenuation capacity. The optimized bicontinuous network exhibits a broad effective absorption bandwidth of 8.62 GHz and a strong RLmin of −52.31 dB. Furthermore, the resulting bicontinuous Si3N4/SiC network, with thickness of 6 mm, shows a tunable absorption bandwidth ranging from 5.36 to 18 GHz by resilient action. It also exhibits excellent thermal stability (up to 1000 °C), thermal shock resistance (from −196 to 900 °C), and thermal insulation performance (32 Mw m−1 K−1), enabling it to be an ideal candidate for EMW absorption in extreme environments. [ABSTRACT FROM AUTHOR]

Light, strong, and elastic ceramics are of great interest for widespread engineering applications but it is always been a challenge to design and fabricate such materials for the conflict that lightweight structure usually requires high porosity while high porosity often leads to low strength. Here, we report a lightweight (90.9% porosity) and ultra‐strong SiC nanowires network (SiC NN) constructed by highly inter‐bonded nanowires in a layered distribution through a facile way. The resulting lamellar SiC NN (L‐SiC NN) exhibits a nearly complete compressive resilience from 20% strain while showing significantly high compressive stress (5.7 MPa). In particular, the L‐SiC NN shows high storage modulus (12.3 MPa), small damping ratio (0.046), frequency invariant from 20 to 100 Hz, and fatigue resistance up to 100 000 compression‐release cycles. In addition, the L‐SiC NN possesses high‐temperature stability up to 1100°C in air and low thermal conductivity of 0.121 W m‐1 k‐1. These integrated features make the L‐SiC NN an attractive substitute for thermal insulators and mechanical energy storage in a harsh environment. [ABSTRACT FROM AUTHOR]