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Compared with optical black, few attempts have focused on achieving broadband microwave blackbodies. In this study, all‐ceramic metamaterial microwave blackbodies are created by integrating a graded Gyroid shellular (GGS) metastructure design with additive manufacturing of polymer‐derived SiOC (PDCs‐SiOC) ceramics encapsulated by Si3N4 (SiOC@Si3N4). Hardly influenced by the destructive interference effect, as‐fabricated GGS‐structured SiOC@Si3N4 microwave blackbodies demonstrate a broadband microwave absorption (MA) above 83.6% (91.3% on average) across the entire X‐Ku band and encompassing higher frequencies above 18 GHz as well, together with the temperature insensitivity from room temperature to 500 °C. Based on the flexible electromagnetic tunability of PDCs‐SiOC, exceptional structural scalability is experimentally validated for metal‐doped modified CuSiOC and CoSiOC substrates with the same GGS metastructures, retaining high‐efficiency MA capability. Furthermore, attachment of perfectly reflecting metal backplanes further enhances the MA performance, with an ultrawide MA exceeding 67.9% (89.1% on average) achievable at 2.95–18 GHz for CoSiOC substrate. Meanwhile, the GGS‐structured SiOC@Si3N4 metamaterials possess additional multifunctional properties, such as good noise reduction performance as well as ultrahigh wear resistance. As a proof of concept, this study provides important guidance on achieving multifunctional coupling broadband MA characteristics by fully tapping the application potential of existing materials. [ABSTRACT FROM AUTHOR]

Ti-doped polymer-derived SiOC ceramic has multi-functional sensing capability due to its semiconductive properties. Their mechanical and chemical stability provide reliable support for their long-term service and safe operation in extreme environments. The sensing properties of Ti-doped SiOC (SiTiOC) can be optimized by modulation carrier concentration. Meanwhile, it can be fabricated by 3D printing as structural-strengthened components, promising for abnormal environmental signals warning under harsh conditions. In this work, SiTiOC gyroid structures were constructed by vat photopolymerization. The resulting components had thermistor characteristics with a negative temperature coefficient. After the Ti doping, the structures exhibited a high conductivity of 1.10 S/m, as the Ti ions formed an efficient percolation network by introducing acceptor impurities. The structures also had piezoresistive capability as the conductive phases can generate a tunneling-percolation conduction effect. They can detect a strain of less than 0.5%. Furthermore, the structures can realize n-butanol sensing for their p-type semiconductor properties. The components also had an excellent mechanical performance with the compressive strength and Young's modulus of 92.83 MPa and 4.28 GPa, respectively, ensuring reliable service under pressure loading. [Display omitted] • Ti-doped semiconductive SiOC gyroid structures fabricated by 3D printing for temperature, pressure, and gas sensing. • Precursor modification for vat photopolymerization and semiconductive properties modulation. • Reliable mechanical behaviors for detection under harsh environments. [ABSTRACT FROM AUTHOR]

Details are presented of an analysis and computer code for the calculation of complex multi-span rotor-bearing-pedestal-foundation systems. This multi-level system analysis is based on the Prohl-Myklestad transfer matrix method. The rotor model used is similar to that given by Lund and Orcutt [1]. Eight-coefficient bearings are also used, to permit elliptical orbit rotor motions. The bearings are mounted in massive, damped flexible pedestals, which are themselves mounted upon a foundation structure with distributed mass and stiffness properties. The foundation in turn, is supported on a number of flexible-damped supports. Different foundation properties in the horizontal and vertical directions are included. The analysis is described in detail, along with the computer code, and the results obtained with it are compared with data published previously by other investigators. It is shown that transfer matrix methods can be successfully used for multi-level systems, and that the additional computational effort involved is moderate. Three applications of the code are described which validate various aspects of the analysis and the computer program.

High reliability and high‐performance electromagnetic interference (EMI) shielding polymeric composite was fabricated by introducing carbon nanotube films (CNTf) into an epoxy (EP) matrix as mechanical and EMI shielding reinforcement simultaneously. According to the computed tomography (CT) detection recorded by a high‐speed camera, CNTf exhibited excellent mechanical behavior and good energy absorption. While being introduced into laminated EP composite, the CNTf enhanced both the mechanical performance and EMI shielding performance. The damage mechanism of CNTf/EP was studied by CT detection of the impact process, indicating that the CNTf absorbed the impact energy by improving the delamination resistance. Additionally, the multilayered CNTf can trap and attenuate the entered electromagnetic microwaves by repeated adsorption, reflection, and scattering in the composite, resulting in excellent EMI shielding performance. Consequently, the energy absorption and the total shielding effectiveness of the CNTf/EP reached to 4.58 × 10−3 J and 52.31 dB, respectively. Therefore, we demonstrated that the CNTf was an ideal functional reinforcement for mechanically strong and high‐performance EMI shielding polymeric composites and the CNTf reinforced EP composite is promising in practical EMI‐shielding applications. [ABSTRACT FROM AUTHOR]

Two‐dimensional (2D) carbon fiber reinforced silicon carbide (C/SiC) composites with different initial strength were prepared by chemical vapor infiltration (CVI). After tensile property testing, results exhibited that as the heat‐treatment temperature (HTT) increases to 1900°C, the tensile strength and toughness of the low strength specimen (LSS) increased by 110% and 530%, while the high strength specimen (HSS) increased by 5.4% and 550%, respectively. As observed from morphologies, the heat treatment increases the graphitization of the amorphous PyC interphase, which leads to the weakening of interfacial bonding strength (IBS). Meanwhile, the defects arising from heat treatment cause thermal residual stress relaxation. Therefore, the tensile strength and toughness of LSS with relatively high initial IBS increase significantly as HTT increases. For HSS with moderate initial IBS, the heat treatment slightly improves the tensile strength, but significantly improves the toughness. Consequently, the post‐heat‐treatment tensile properties of 2D C/SiC composites can be regulated by varying HTTs and different initial strength. [ABSTRACT FROM AUTHOR]

Developing advanced three‐dimensional (3D) structural supercapacitors with both high capacity and good mechanical strength remains challenging. Herein, a novel road is reported for fabricating 3D structural strengthening supercapacitors with adjustable capacitance based on urchin‐like Cu(OH)2 lattice electrodes by bridging 3D printing technology with a facile electroless plating and electro‐oxidation method. As revealed by the results, the 3D‐printed octet‐truss lattice electrode features a high volumetric capacitance of 8.46 F cm−3 at 5 mA cm−3 and superior retention capacity of 68% at 1 A cm−3. The assembled symmetric supercapacitor with a 70.2% capacitance retention after 5000 cycles possesses a 12.8 Wh kg−1 energy density at a power density of 2110.2 W kg−1. Additionally, the resulting 3D structural strengthening electrodes can achieve both high compressive strength and toughness of 30 MPa and 264.7 kJ m−3, respectively, demonstrating high mechanical strength and excellent antideformation capacity. With the proposed strategy, the electrochemical and mechanical properties of these novel 3D structural strengthened supercapacitors can be easily tuned by a simple spatial framework design, fulfilling the increasing demand of highly customized power sources in the space‐constrained microelectronics and astronautic electronics industries. [ABSTRACT FROM AUTHOR]