Biosynthetic gas vesicles (GVs) have garnered substantial attention owing to their potential as novel ultrasound contrast agents. Compared to traditional microbubble contrast agents, GVs have numerous evident advantages, including nanoscale size, good stability, low cost, and biocompatibility. More importantly, GVs can function as acoustic reporter genes for cell imaging owing to their gene-encoding features. Numerous new versions of GVs have been developed by heterologously expressing GV-encoding gene variants in recombinant Escherichia coli. However, only a few genetically engineered bacteria can successfully produce GVs, which limits their biomedical applications. Therefore, a precise, simple, and rapid method for sorting GV-containing bacteria must be developed. Here, we propose a phononic crystal-based sorting method and fabricate a fully packaged acoustofluidic device that can separate GV-containing E. coli (GVs-E. coli) from non-GV-containing E. coli based on the differences in their acoustic contrast factor and in the radiation forces produced by the localized sound field of an integrated resonant phononic crystal plate. The isolated GVs-E. coli demonstrated a purity exceeding 90%, with 89% purification efficiency. This study provides a powerful method for screening GV-containing cells and a perspective for the biomedical applications of acoustic metamaterials.

High-throughput and biocompatible acoustofluidic manipulation of living cells and microparticles is essential for applications in cellular medicine, tissue engineering, and drug screening. Conventional surface acoustic wave (SAW)-based devices have been widely adopted; however, their high operating frequencies limit throughput, and the conversion of SAWs into leaky bulk waves in liquids induces strong acoustic streaming that compromises manipulation stability. Here, we present a low-frequency acoustofluidic device that exploits non-leaky quasi-Scholte waves in a piezoelectric thin plate to achieve high-throughput, stable, two-dimensional manipulation of particles and cells. Numerical simulations and laser Doppler vibrometry measurements confirm robust excitation of the quasi-Scholte mode, revealing evanescent acoustic fields with strong vertical gradients and well-defined in-plane standing waves in liquid. Experiments with microparticles and in vitro cells further demonstrate stable one- and two-dimensional patterning over large areas while maintaining high cell viability. This quasi-Scholte-wave-based acoustofluidic platform provides a reliable, effective, and high-throughput approach for precise manipulation of cells and biomaterials.

High-entropy ultrahigh temperature ceramics (UHTCs) have garnered significant attention for their outstanding designability and performance, yet existing strategies remain largely confined to cationic sublattice engineering, leaving the potential of anionic site manipulation unexplored. Herein, we extend the entropy-stabilization paradigm to the anion sublattice by designing a multianion Hf0.8Zr0.2B0.1C0.5N0.4 solid solution. The resulting Hf0.8Zr0.2B0.1C0.5N0.4–SiC ceramic achieves negative ablation rates (−0.049 and −0.287 μm·s−1) under 2600 °C plasma flame exposure, markedly outperforming Hf0.8Zr0.2C–SiC. This exceptional ablation-resistant performance originates from the synergistic effects enabled by multianion sublattice engineering. The incorporation of B–C–N intrinsically enhances fracture toughness, while in situ precipitation of hexagonal graphite during ablation extrinsically arrests cracks through interfacial shear, preventing catastrophic disintegration. Furthermore, the multianion matrix undergoes a sequential oxidation process, forming an HfZrBCNO interlayer that acts as an oxygen scavenger. Concurrently, h-BN precipitates at grain boundaries, serving as compliant diffusion barriers that impede oxygen ingress into SiC. This dual-layer protection mechanism suppresses the active oxidation of SiC (SiC + O2 → SiO + CO) and promotes the formation of a dense, scouring-resistant HfZrO2–SiO2 composite barrier. By demonstrating simultaneous microstructural toughening and mesoscale oxidation management, this work establishes multianion sublattice engineering as a transformative platform for designing next-generation thermal protection materials beyond the limits of conventional entropy-stabilized ceramics.

High-entropy ultrahigh temperature ceramics (UHTCs) have garnered significant attention for their outstanding designability and performance, yet existing strategies remain largely confined to cationic sublattice engineering, leaving the potential of anionic site manipulation unexplored. Herein, we extend the entropy-stabilization paradigm to the anion sublattice by designing a multianion Hf0.8Zr0.2B0.1C0.5N0.4 solid solution. The resulting Hf0.8Zr0.2B0.1C0.5N0.4u2013SiC ceramic achieves negative ablation rates (u22120.049 and u22120.287 u03BCmu00B7su22121) under 2600 u00B0C plasma flame exposure, markedly outperforming Hf0.8Zr0.2Cu2013SiC. This exceptional ablation-resistant performance originates from the synergistic effects enabled by multianion sublattice engineering. The incorporation of Bu2013Cu2013N intrinsically enhances fracture toughness, while in situ precipitation of hexagonal graphite during ablation extrinsically arrests cracks through interfacial shear, preventing catastrophic disintegration. Furthermore, the multianion matrix undergoes a sequential oxidation process, forming an HfZrBCNO interlayer that acts as an oxygen scavenger. Concurrently, h-BN precipitates at grain boundaries, serving as compliant diffusion barriers that impede oxygen ingress into SiC. This dual-layer protection mechanism suppresses the active oxidation of SiC (SiC + O2 u2192 SiO + CO) and promotes the formation of a dense, scouring-resistant HfZrO2u2013SiO2 composite barrier. By demonstrating simultaneous microstructural toughening and mesoscale oxidation management, this work establishes multianion sublattice engineering as a transformative platform for designing next-generation thermal protection materials beyond the limits of conventional entropy-stabilized ceramics.

Short carbon fiber reinforced ultrahigh temperature ceramic matrix composites (Csf/UHTCMCs) are recognized as leading candidates for thermal structures owing to their precisely tailorable composition and enhanced tunability in structure and properties. Inspired by nature, the Bouligand structure-characterized by a gradual angular rotation between successive layers-exhibits remarkable load-bearing and thermal conductive capacity. In this study, the Bouligand structure was introduced into Csf/ZrB2-SiC by employing direct ink writing technology. The results indicate that the composite with a 30 degrees interlayer Bouligand structure achieves a synergistic improvement in both mechanical performance and thermal diffusion uniformity. Specifically, enhancements of 42% in flexural strength and 35% in fracture toughness were achieved compared to conventional Csf/ZrB2-SiC. Meanwhile, the Z-axis thermal conductivity increased by 24.5%, along with a notable enhancement of in-plane thermal diffusion. These improvements can be attributed to the smaller deflection angles and more frequent unidirectional deflections within the 30 degrees Bouligand structure, which promote more pronounced crack deflection. Furthermore, the small-angle rotational design improves in-plane thermal diffusion uniformity by leveraging the high intrinsic radial thermal conductivity of short carbon fibers. Hence, the bioinspired Bouligand structure design offers a promising strategy for the synergistic optimization of mechanical and thermal properties in Csf/UHTCMCs.

Pr3Si2C2-xOx was employed as a sintering additive to enable low-temperature densification of SiC ceramics. Dense SiC ceramics were obtained through hot pressing at 1550 °C under 20MPa. During sintering, Pr3Si2C2-xOx undergoes oxygen-assisted phase transformation, decomposing into SiC and crystalline Pr-O compounds that form stable solid-solid interfaces at grain boundaries. Microstructural analysis using TEM, HRTEM, and EDS confirmed the formation of these crystalline intergranular phases, while EELS demonstrated partial oxygen substitution in the Pr3Si2C2 lattice. Mechanical testing under an Ar atmosphere revealed that the sample with Pr:Si atomic ratio of 1:7 retained a flexural strength of 313MPa at 1400 °C, corresponding to 95% of its room-temperature strength. Compared with conventional liquid-phase-sintered SiC, the crystalline grain-boundary phases significantly suppress intergranular softening at elevated temperatures. This work establishes a clear link between additive-induced microstructural evolution and high-temperature mechanical stability, providing a promising strategy for the low-temperature fabrication of high-performance SiC ceramics.

Near-fully dense SiC ceramics were fabricated via hot pressing at 1650 degrees C using Pr3Si2C2 as a sintering aid, and their high-temperature oxidation behavior was systematically investigated at 1200-1400 degrees C. The results demonstrate that Pr3 + gradually migrates toward the oxide layer surface and reacts with SiO2 to form Pr2Si2O7, with temperature-dependent structural transitions. Above 1300 degrees C, a dense dual-layer structure forms, comprising an outer Pr2Si2O7 crystalline layer and an inner SiO2-rich layer, which effectively suppresses oxygen diffusion. Consequently, the oxidation activation energy increases from 24.3 kJ/mol (1200-1300 degrees C) to 416.3 kJ/ mol (1300-1400 degrees C). Mechanistic studies reveal that Pr3+ migration is driven by both a concentration and a potential gradient. This dual driving mechanism enables the self-organization of a continuous Pr2Si2O7 barrier layer, significantly enhancing oxidation resistance. These findings provide critical insights into the design of SiCbased ceramics for use in extreme environments.

ABSTRACT A novel Pr 3 Si 2 C 2 additive was introduced to lower the sintering temperature of NITE‐SiC f /SiC composites to 1550°C–1650°C. Pr 3 Si 2 C 2 effectively promoted densification, achieving 3.11 g/cm 3 density and 4.9% open porosity at 1600°C. However, the densification process causes severe thermochemical damage to the interphase layers and fibers. At 1550°C–1600°C, a kinetically‐dominated “transient Pr‐rich layer” is formed at the fiber/interphase boundary. This stems from a three‐order‐of‐magnitude disparity in Pr‐ion diffusion coefficients between the BN interphase and SiC fiber (At 1550°C, D BN ≈ 9.66 × 10 −13 m 2 /s vs. D SiC ≈ 8.31 × 10 −16 m 2 /s). Above 1650°C, Pr 3 Si 2 C 2 decomposition products react with the BN to form SiC, Pr 25 B 14 C 26 , and Pr 6 O 11 , shifting interfacial bonding from weak (23 MPa) to strong (154 MPa). Concomitantly, the Pr‐bearing liquid phase infiltrates fibers along grain boundaries, inducing abnormal grain growth (from 8.8 to 54 nm) via Ostwald ripening. This caused monofilament tensile strength to drop from 2771.5 to 624.6 MPa and the Weibull modulus from 6.11 to 3.65. Combined interfacial degradation and fiber lead to a decline in composite performance, with the fracture mode shifting from pseudoplastic to brittle. This study elucidates the corrosion mechanisms of Pr 3 Si 2 C 2 on SiC fibers and BN interphases, providing a crucial theoretical foundation for optimizing the processing window of NITE‐SiC f /SiC composites.

The sandwich structure with ceramic matrix composites (CMCs) skin and carbon form (CF) core is the ideal thermal structural components with excellent thermal protective and lightweight properties in hypersonic vehicles. However, the temperature gradient and mismatch of thermal conductivity between CMC skin and CF core result in the thermal stress in sandwich structures. Therefore, core material CF with matching thermal conductivity have become very important to prevent cracks and debonding of the sandwich structure. In this work, carbon nanotubes (CNTs) reinforced carbon foam composites with different microstructure were fabricated using simple phenolic resin foaming followed by CVI process. The prepared CF display a very low density of 0.075 g/cm3 and a relatively high compressive strength of 1.65 MPa. By controlling the distribution position and content of CNTs the thermal conductivity of core materials CF/CNTs (4.93 W·m− 1·K− 1 which is 13 times higher than that of CF) can be regulated to compatibility with CMCs skin (3.5 6.0 W/m·K). And the thermal conductivity evolution mechanisms of the CF/CNTs from room temperature to 1200 ℃ were revealed. High interfacial thermal resistance by phonon scattering between the CF and CNTs blocks the solid conduction of materials at room temperature. With the increase of the temperature, radiative heat transfer between CF and CNTs becomes more violent and dominates the heat transfer path. The C/CMCs-CMCs sandwich structure was fabricated quickly by the in situ foaming method.

In this work, continuous and dense Yb2Si2O7 coating was formed on the surface of SiC fibers by reaction of the Yb2O3 coatings prepared via urea-based homogeneous precipitation with SiO2 scales formed by fiber oxidation. The effect of SiO2 to Yb2O3 thickness ratio on the microstructure and morphology of Yb2Si2O7 coatings was investigated. Fiber oxidation and defects introduced during coating synthesis cause severe fiber degradation, and pre-deposition of SiC via chemical vapor infiltration can improve the strength retention of the fibers. The Yb2Si2O7 coatings can protect fibers from corrosion in water vapor environment at 1200 degrees C, showing great resistance to oxidation.

Ultra-high temperature ceramic matrix composites (UHTCMCs) are leading candidates for aerospace thermal protection, wherein fiber selection critically determines their ultimate performance. This work investigates hybrid Cf /ZrC-SiC composites reinforced with polyacrylonitrile-based carbon fibers (PANCF) and mesophase pitch-based carbon fibers (MPCF) at varying ratios. The composite with an MPCF: PANCF ratio of 3:1 achieves balanced thermomechanical performance with a flexural strength of 416 MPa (an 11.53% increase over the pure MPCF composite) and a thermal conductivity of 77.05 W.m(-1).K-1 (a 626.20% increase over the pure PAN composite). Finite element analysis confirms that high thermal conductivity promotes rapid heat dissipation, reducing surface overheating. After ablation testing at 3.3 MW/m(2) for 90 s, PM3 achieves linear and mass ablation rates of 2.332 mu m/s and 0.949 mg/s, respectively, with a surface temperature 182 degrees C lower than that of the pure PAN composite. Enhanced thermal transport promotes a thinner and more uniform oxide layer, and increases viscosity through fine ZrO2 precipitation in the SiO2 glassy phase. This work provides a novel strategy for designing UHTCMCs with co-optimized mechanical and thermal properties.

Acoustic wave resonators have long been recognized as versatile, biocompatible tools for particle manipulation. However, their application in sensing the quantity and properties of particles remains a relatively underexplored research area. Herein, we propose an acoustic annular slotted resonator (AASR) system capable of simultaneously trapping and sensing subwavelength particles. The dual-function mechanism of this system originates from intense interactions between highly localized resonant acoustic fields and subwavelength particles within the subwavelength annular slot. Specifically, these interactions significantly enhance the acoustic radiation force, enabling efficient trapping of subwavelength particles at multiple stable positions. This trapping effect further amplifies the acoustic wave-particle interaction, ultimately boosting the system’s sensing performance. Numerical results demonstrate that the resonance frequency of the AASR system exhibits a strong dependence on both the quantity and type of subwavelength particles. Owing to its high sensitivity, compact size, and small amount of particle sample, the AASR system holds substantial potential for broad applications, including biochemical detection and environmental monitoring.

In this work, YB4-CrSi2 surface-modified Cf/ZrB2-SiC composites were fabricated by a slurry coating method. The cyclic ablation resistance of the composites was studied at 2600 degrees C for 300 s using an air plasma test. The ablation mechanisms of the composites were discussed. The Y3+ can prevent the phase transition of the ZrO2 and increase the structural stability of the oxide layer. But the oxide layer cannot prevent the inward O penetration resulting from the forming of Zr0.9Y0.1O1.95 grains with abundant oxygen vacancy. After the modification of CrSi2, the size of Zr0.9Y0.1O1.95 grains can be reduced to nano scale. The adequate SiO2 glassy phase with the uniform distribution of the Zr0.9Y0.1O1.95 nano grains can prevent the O penetration effectively and reduce the mass recession rate of the composites.

Aerogel and its phase change composites are two reliable strategies for thermal management. However, the inherent instability of these porous structures hinders their further development and application. Herein, a robust boron nitride metamaterial (BNM) enhanced by the negative Poisson's ratio effect is proposed for dual thermal management strategies obtained by the sacrificial template method. The negative Poisson's ratio confers enhanced structural stability to the BNMs. On the one hand, the BNM exhibits resilience (5% residual strain after 100 cycles), temperature invariance, fire resistance, and thermal superinsulation at high temperatures (102.83 mWm(-1)K-1 at 1000 degrees C). On the other hand, the robust BNM overcomes structural deformation during the vacuum impregnation process to obtain isotropic phase change composites, achieving efficient thermal conductivity (1 Wm(-1)K-1 with 4 vol% BNM) and thermal conductivity enhancement effect of 97%. These composites effectively encapsulate phase change materials, preventing liquefaction and leakage. This approach offers a reliable solution for simultaneously improving both the thermal management strategies.

To enhance the service life and reliability of SiCf/SiC composites after EBCs exfoliation, an integrated design concept is proposed to use Si reactive melt infiltration to prepare integrated EBC- SiCf/SiC composites in this work. It can form a quasi-EBC layer with EBC components on the surface of SiCf/SiC composites. The integrated structure has stronger bonding strength than the conventional coating and matrix. During thermal shock cycling, its thermal shock resistance can be enhanced by consuming SiO2 to form Yb2Si2O7 with good damage tolerance. Meanwhile, the presence of quasi-EBC layer is expected to provide secondary protection for SiCf/SiC composites after conventional EBC stripping, which can improve the service life of SiCf/SiC composites. This work provides a new idea for the long-life modification of SiCf/SiC composites.

Ultrahigh temperature and long-term ablation-resistant properties are critical and challenging for the utilization of materials as the thermal components of hypersonic vehicles. In this work, Y2O3 reinforced C-f/HfB2-SiC composites are designed and fabricated, which present superior ablation resistance with a mass recession rate of 2.10 mg/s and linear recession rate of 0.67 mu m/s (with 3 wt% Y2O3 addition) under long term ablation at a heat flux of 5.5 MW/m(2) (up to similar to 2700 degrees C) for 300 s. The long-term ablation mechanisms of the composites are studied and revealed with the help of a detailed microstructure analysis and thermodynamic considerations. It is indicated that Y2O3 reacts with both HfO2 and SiO2, leading to the formation of a stable oxide layer with small HfO2-based grains skeleton dispersed in HfO2-Y2O3-SiO2 glassy phase, subsequently improving the ablation-resistant performance of the composites. This work inspires new strategies for further optimization of ablation resistance of ultra-high temperature ceramic matrix composites.

Non-contact and label-free acoustic manipulation of particles is crucial for various applications ranging from cell separation and tissue engineering to micromachining and nanofabrication. Surface acoustic waves (SAWs) have been widely used for microscale particle manipulation; their leaky nature in liquid often generates significant bulk acoustic streaming that undermines stable trapping of nanoscale particles. To address this challenge, we introduce an acoustofluidic device comprising a zinc oxide (ZnO) thin film deposited on aluminum foil with one-sided water loading. This design excites quasi-Scholte waves, a specialized nonleaky mode confined to the fluid-solid interface, which effectively suppresses bulk streaming and enables stable nanoparticle trapping. Both theoretical modeling and experiments confirm that the resulting strongly evanescent field operated at 5.11 MHz generates negative vertical forces and strong lateral (in-plane) trapping forces, successfully trapping 250 nm-radius particles on the foil surface. As the particle radius decreases to 150 nm, streaming-induced drag becomes the dominant manipulation mechanism. Operable at low frequencies with a simple and scalable design, our platform offers a versatile route for precise nanoscale particle trapping, with significant potential for bioengineering and nanofabrication applications.