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81.
《Ceramics International》2023,49(13):21695-21707
0.96BaTiO3-0.04Bi(Mg1/2Ti1/2)O3 (0.96BT-0.04BMT) + y wt.% Nb2O5 ceramics (0.0 ≤ y ≤ 2.0) were sintered at 1275 °C to fabricate a ceramic with a large εr for an X8R multilayer ceramic capacitor (MLCC). Addition of Nb2O5 afforded a core–shell structure, and the compositions of the core and shell regions were similar to those of BT and BT-BMT, respectively. The sample (y = 1.25) exhibited a large εr of 2285 with a good temperature stability satisfying the X8R specification because of a broad shell-region phase-transition peak at −17 °C and a decreased εr of the core-region phase-transition peak. The 0.1 wt% BaO–CaO–SiO2 (BCS) was used to reduce the sintering temperature, and the 9-layered MLCC produced using a BCS-doped 0.96BT-0.04BMT + 1.25 wt% Nb2O5 ceramic at 1200 °C showed a large capacitance of 67 nF with a good temperature stability thus complying with EIA-X8R regulations. 相似文献
82.
《Ceramics International》2023,49(13):21570-21576
Aerosol deposition (AD) is a room-temperature ceramic coating method, which has been used for many applications. Various substrates, such as metals and ceramics, have been used depending on the application, but it is not clear how the substrate microstructure affects the deposition processes and film quality. In this study, AD alumina films deposited on silicon substrates with microstructures consisting of line and space patterns were systematically investigated. The films were formed along the microstructure on the substrate when the linewidth was much larger than the grain size of the raw powder. Conversely, on narrow-linewidth substrates, the films were supported by the lines and the spaces were sealed. The effect of the substrate microstructure was analyzed in terms of the residual stress of the films. 相似文献
83.
Fei Jin Yuanming Zhu Li Li Zizhao Pan Desheng Pan Meng Gu Qian Li Lang Chen Hong Wang 《Advanced functional materials》2023,33(16):2214273
Ferrimagnetic insulator materials are the enabling technology for the development of next-generation magnetic devices with low power consumption, high operation speed, and high miniaturization capability. To achieve a high-density memory device, a combined realization of robust saturation magnetization (Ms), controllable magnetic anisotropy, and high resistivity (ρ) are highly demanded. Despite significant efforts that have been made recently, simultaneously achieving significant enhancements in these properties in a soft magnetic insulator material still remains a great challenge, severely limiting their practical application. Herein, a high-entropy strategy in an ultra-thin spinel ferrite (CrMnFeCoNi)3O4 film is reported that exhibits concurrently a superior saturation magnetization (MS = 1198 emu cm−3), low coercivity (HC = 90 Oe), and excellent resistivity (ρ = 1233 Ω cm), as well as switchable magnetic anisotropy. The comprehensive lattice probing and microstructure analysis studies reveal that such desirable ferromagnetic properties originate from the high-quality structurally ordered but compositionally disordered single-crystal epitaxial structure. The switchable magnetic anisotropy demonstrated in the high-entropy ferrite film can be attributed to the new antiferromagnetic rock-salt phase. This work unveils the critical benefits of the high-entropy strategy for magnetic oxide thin films, which opens up new opportunities for the development of high-performance magnetic materials. 相似文献
84.
Waqas Ahmad Liang Pan Karim Khan Lingpu Jia Qiandong Zhuang Zhiming Wang 《Advanced functional materials》2023,33(19):2300686
Van der Waals (vdWs) heterostructures enable bandgap engineering of different 2D materials to realize the interlayer transition via type-II band alignment leading to broaden spectrum that is beyond the cut-off wavelength of individual 2D materials. Interlayer transition has a significant effect on the optoelectronic performance of vdWs heterostructure devices, and strong interlayer transition in 2D vdWs heterojunction is always demandable for sufficient charge transfer and rapid speed response. Herein, a state-of-the-art review is presented on recent progress on interlayer transition in vdWs heterostructures for near-infrared (NIR) photodetectors. First, the general synthesis techniques for vdWs heterostructures, band alignments in the vdWs heterostructures are provided. Then, the mechanism of interlayer transition in vdWs heterostructure and recent progress on interlayer transition in vdWs heterostructures for NIR photodetectors are summarized. Afterward, some worthy applications of NIR photodetectors are reviewed in related areas of this topic. At the last, an outlook, challenges, and future research directions of vdWs heterostructures for photodetectors at broaden response spectrum are presented. 相似文献
85.
《International Journal of Hydrogen Energy》2023,48(38):14271-14278
Accelerating the charge separation and transfer as well as increasing the visible light absorption is of great importance for photocatalysts to realize efficient photocatalytic hydrogen evolution via water splitting. Herein, for the first time, we fabricated in-plane graphited nanocarbon-conjugated polymeric carbon nitride (GNC-C3N4) nanosheet heterostructure photocatalyst from melamine and hexaketocyclohexane octahydrate mixture via an amino-carbonyl reaction. The incorporation of GNC into conjugate network of C3N4 can not only dramatically enhance the light harvesting but also significantly promote the charge separation and transfer by the built-in electric field and intimate interface in the coplanar GNC-C3N4 heterostructure. Accordingly, the optimal GNC-C3N4 photocatalyst demonstrates a more than 15-fold enhancement for photocatalytic hydrogen evolution from water under visible light irradiation, compared to C3N4. 相似文献
86.
《International Communications in Heat and Mass Transfer》2006,33(8):976-984
A numerical experiment has been carried out to study the thermal performance of a large solar collector assembly, which could be integrated as part of the roof structure without undue difficulties. The collector assembly consists of a network of riser tubes and headers as if rows of flat-plate collectors are connected in series to form a large flat-plate collector. Results show that the thermal efficiency of the collector assembly is mainly influenced by the number of riser tubes, collector aspect ratio (H/W), mass flow rate, thermal conductivity and thickness of absorber plate. Differences in the range of 2.5%–8% were detected depending on the specific parameter tested. 相似文献
87.
88.
Poly(3-alkylthiophene) (P3AT) with a high Seebeck coefficient has recently been reported. However, P3AT/inorganic conductive composites exhibit relatively poor thermoelectric performance because of their low electrical conductivity. In this work, carbon fiber sheets with a high electrical conductivity were chosen as the inorganic phase, and poly(3-octylthiophene)(P3OT)/carbon fiber composites were prepared by casting P3OT solution onto the carbon fiber sheets. The carbon fiber sheets incorporated into the composites can provide good electrical conductivity, and P3OT can provide a high Seebeck coefficient. The highest power factor of 7.05 μW m−1 K−2 was obtained for the composite with 50 wt% P3OT. This work suggests a promising method for preparing large-scale thermoelectric composites with excellent properties. 相似文献
89.
《Composites Science and Technology》2003,63(3-4):403-419
Interfacial properties and microfailure degradation mechanisms of the bioabsorbable composites for implant materials were investigated using micromechanical technique and nondestructive acoustic emission (AE). The tensile strength of absorbable fibers with hydrolysis was analyzed statistically using either uni- or bimodal Weibull distribution. As hydrolysis time increased, the tensile strength, the modulus and the elongation of poly(ester-amide) (PEA) and bioactive glass fibers decreased, whereas those of chitosan fiber almost did not change. Interfacial shear strength (IFSS) between bioactive glass fiber and poly-l-lactide (PLLA) was much higher than PEA or chitosan fiber/PLLA systems using dual matrix composite (DMC) specimen. The decreasing rate of IFSS was the fastest in bioactive glass fiber/PLLA composites whereas that of chitosan fiber/PLLA composites was the slowest. Work of adhesion, Wa between bioactive glass fiber and PLLA was the highest, and the wettability results were consistent with the IFSS. AE energies of PEA fiber decreased gradually, and their distributions became narrower than those in the initial state with hydrolysis time. In case of bioactive glass fiber, AE energies in tensile failure were much higher than those in compression. In addition, AE parameters at the initial state were much higher than those after degradation under both tensile and compressive tests. Interfacial properties and microfailure degradation mechanisms can be important factors to control bioabsorbable composite performance. 相似文献
90.
The behaviour of inclusion initiated fatigue was studied for a high strength bearing steel with a bainite micro-structure. The analysis included experiments and numerical simulations. It was realized that the stress-state was multi-axial in the matrix material that met the inclusion also for a uniaxial far field stress. Fatigue initiation risk at the interface between the inclusion and matrix material was therefore predicted with the Findley multi-axial critical plane criterion. The fatigue parameters were determined from independent experiments on smooth specimens with tensile surface stress gradients. Crack growth from the inclusion to final rupture was modelled as a penny shaped crack with closure compensated effective material parameters. The growth simulations suggested that the majority of the fatigue life was consumed as fatigue crack initiation at the non-metallic inclusion. 相似文献