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The effect of Fe-C alloy additions on thermal, mechanical and corrosive properties of (Cu50Zr40Ti10)1-x(Fe-C)x (x = 0–2.20 at%) alloys were systematically investigated. The results show that the Fe and C additions can enhance glass transition temperature Tg and onset crystallization temperature Tx, but narrow supercooled liquid region ΔTx. Work-hardening can be clearly observed for the Cu-based bulk metallic glasses (BMGs) containing Fe and C elements. The yield strength (σy), fracture strength (σf) and plastic strain (ep) are drastically increased by Fe-C alloy additions. The corrosion potential Ec increases and the corrosion current density ic decreases with increasing Fe and C contents. The studied Cu-based BMGs exhibit unique and novel anodic polarization behavior characterized by current platforms plus current serrations. The current serrations are much larger for the Cu-based BMGs with 0 ≤ x ≤ 1.32 at% than for those with 1.76 ≤ x ≤ 2.20 at%. The corrosion surface images are changed from the pits to the passive films by Fe-C alloy additions. The corrosion behavior gradually transforms from the pitting corrosion to the self-passivization with increasing Fe and C contents. The corresponding mechanisms are also discussed.

MXene, especially Ti3C2Tx, is attracting extensive attention as an absorbing material owing to its strong dielectric loss and tunable structure. Nevertheless, extremely high conductivity and non-magnetic loss mechanism limit the absorbing intensity and effective absorption bandwidth (EAB). Herein, the magnetic ZnFe2O4 nanoparticles decorated Ti3C2Tx MXene composite is designed and synthesized by using a facile in-situ solvothermal method. The novel ZnFe2O4@Ti3C2Tx-2 (1:2) composite shows an optimal reflection loss of −60.94 dB and a wide EAB of 6.08 GHz at a matching thickness of only 1.75 mm. The mechanism analysis reveals that the synergetic electromagnetic loss effect, interfacial polarization, dipole polarization, and laminated structure contribute to improving the microwave absorption (MA) performance. Furthermore, to confirm the use capability of the ZnFe2O4@Ti3C2Tx sample coatings in practical applications, the radar cross-section (RCS) reduction performance has been proved through using computer simulation technology (CST). With the detection theta of 0°, the ZnFe2O4@Ti3C2Tx-2 sample coating possesses the largest RCS reduction value of 22.83 dB. This work lays the foundation for the rational design of high-performance absorbing materials.

Confining ZnO quantum dots (QDs) into a solid state matrix to form nanocomposite materials is an important mean to design nonlinear optical devices. In this paper, ZnO confined in Al2O3 matrix are synthesized by pulsed laser deposition method and rapid thermal annealing technique. The substantial oxygen vacancies are generated in the N2-annealed ZnO QDs. Magnetic measurements illustrate that the ferromagnetic nature of ZnO QDs confined in Al2O3 matrix can be due to the oxygen vacancies. The determined two-photon absorption in N2-annealed ZnO QDs is an instantaneous nonlinear process and is enhanced almost 2 times compared to that of O2-annealed ZnO QDs. The enhancement of optical nonlinearities achieved in confined ZnO QDs with substantial oxygen vacancies is important for the practical applications of ZnO nanostructures in such as optical limiting devices and all-optical switching elements.

Efficient, flexible, thin, and easy processing electromagnetic interference (EMI) performance materials attract attention to prevent increasingly electromagnetic pollution. Herein, we fabricated multiple spatial-scale conductive frameworks containing tantalum carbide (TaC) nanoparticles by electrospinning and high-temperature pyrolysis. The electrospun composite fabrics possess outstanding properties such as an excellent tensile strength of 9.5 MPa and excellent flexibility. Furthermore, the TaC nanoparticles with appropriate concentration can interconnect with each other endowing the composite fabrics with high electrical conductivity of 10.4 S cm−1. It also has great EMI SE of up to 37.7 dB in X band with only 0.2 mm thickness, and the SSE/t values of 4290.1 dB cm2 g−1. Owing to its pore structure, the shielding mechanism is mainly based on reflection and the finite element simulation further visually confirmed the excellent shielding capabilities. This novel electrospun composite fabrics have a great potential to be applied in fields of aerospace, and electronic devices.

Magnetic nitrogen-doped carbon nanotubes have been recognized as promising microstructures for electromagnetic wave absorption, benefiting from the internal hollow structure, excellent electrical conductivity and easy functionalization. Herein, a new composite composed of the thin-wall carbon nanotubes coated with the cobalt nanoparticles (hereafter labelled as: Co@NCNTs) on the tip was designed and synthesized through high temperature pyrolysis process. Revealed by scanning electron microscopy and X-ray photoelectron spectroscopy, the geometric and electronic structures of product were susceptible to the carbonization temperature. With the multiple dielectric polarization relaxations, higher magnetism and good impedance matching, the flammulina velutipes-like Co@NCNTs-700 exhibited the strongest dielectric loss, magnetic loss and electromagnetic wave absorption performance. The minimum reflection loss value and effective absorption bandwidth was determined to be −21.0 dB at 4.96 GHz and 5.28 GHz, respectively, superior to the previous reports. Furthermore, the thickness is at 2 mm and the filler mass loading is only 10%. Therefore, our present Co@NCNTs materials will be an ultralight material as potential high-efficiency EMW absorber.

The magnetic–dielectric composites with synergetic magnetic and dielectric losses have exhibited great potential in the practical applications of microwave absorbing material. This paper reports a simple low-temperature in situ hydrothermal approach for synthesizing novel composites composed of the dielectric Ti3SiC2 wrapped with magnetic CoNi nanoparticles. The microstructure, morphology, electromagnetic properties, and microwave absorption performance of as-synthesized samples were investigated. By adjusting the content of formed magnetic CoNi nanoparticles on the surface of Ti3SiC2, obvious regulated frequency-dependence of electromagnetic parameters for the proposed CoNi/Ti3SiC2 composites can be realized. Consequently, the effective absorption bandwidth (RL

For large-area electronic applications, the mechanism of the leakage current in oxide-semiconductor thin-film transistors (TFTs) has become a critical issue. In this work, the impact of the irradiation location on the photo-leakage current of zinc oxide (ZnO) TFTs is investigated. The photo-leakage current of the ZnO TFTs is not only dependent on the light irradiation but it is also dependent on the parasitic capacitance between the drain electrode and the floating gate metal. The photo-leakage current of the source-half irradiation TFT is larger than that of the drain-half irradiation TFT. To explain this phenomenon, the profile of the electric potential and the electron concentration is analyzed by two-dimensional device simulation. It is found that the floating gate metal plays the dominant role in the photo-leakage current. This research provides insight into TFT structure optimization and high-performance TFT process development.

Under the long-term influence of electrical load and natural environmental factors, the insulation performance of the insulator will gradually decrease, and deteriorated insulators with different degrees of deterioration will appear in the insulator string. The presence of degraded insulators can pose a significant risk to the safe operation of the power system. In order to study the influence of insulators with different degradation degrees on the voltage distribution of insulator strings in 500 kV transmission lines, this paper studies the distribution voltages of different positions, different numbers and different degraded insulators in 500 kV transmission line insulator strings based on finite element method. The simulation results show that the voltage drop of the insulator with a lighter degree of degradation is very low, and it is more difficult to identify by the distributed voltage. The deteriorated insulator has a certain lifting effect on the voltage of its adjacent insulator. Finally, the effects of different degrees of deteriorated insulators on the voltage distribution are studied by experiments. The conclusions are consistent with the simulation results.

MXene-based magnetic–dielectric composites with synergetic magnetic and dielectric losses have exhibited great potential in the practical applications of microwave absorbing material. In the present paper, novel composites consisting of laminated Ti3C2Tx MXene decorated with magnetic FeNi nanoparticles were constructed via a facile in situ hydrothermal approach. The microstructure, morphology, magnetic properties, and microwave absorption performances of as-synthesized samples were investigated in detail, and corresponding mechanisms were further discussed. Results demonstrated that the frequency dependence of electromagnetic parameters for the FeNi/Ti3C2Tx MXene composites could be easily regulated by simply changing the content of FeNi nanoparticles in favor of improved magnetic loss and optimized impedance matching. Consequently, a broadband effective absorption bandwidth (RL

Tailoring the carbon-electrode with rich porosities and heteroatoms has been demonstrated to break the limitation of capacitive storage and microwave absorption, but the balance between them remains a great challenge, resulting in the difficulty to control and utilize the active sites. Here, porous heteroatoms co- and tri-doping carbon nanosheets are easily achieved by a developed melting-pressing-carbonization (MPC) approach with the assistance of g-C3N4, which concurrently activates pore structure and surface properties by serving as structure-directing agent, activating agent and nitrogen resource. The optimized co-doping carbon nanosheet (NPCN-1) exhibits a novel surface structure containing high N (14.1%) contents with well-distributing conductive and redox-active N species, and ions-matched pores centered on 0.7 nm, which provides rich-effective active sites to capture fast electron and ion transport, reflected by the energy storage dynamics. Therefore, the NPCN-1 supplies a large specific areal capacitance of 0.434 F m−2, even outperforming the graphene (0.21 F m−2) as supercapacitor electrode, and displays a broad effective absorption bandwidth of 6.64 GHz and a strong reflection loss of −44.5 dB in microwave absorption (MA). These energy storage and MA capability can be further enhanced after realizing tri-doping of O, N and Fe2O3 by MPC strategy, shedding light on an avenue to future application and development for the active materials.

An optically transparent metamaterial absorber (MMA) operated in the C-band (4–8 GHz) is optimally designed based on the second-order cross fractal structure. The experimental results show that the reflection loss of the proposed MMA is lower than −10 dB from 3.98 GHz to 8.68 GHz. Two overlapped resonances located at 4.77 GHz and 7.33 GHz, respectively, are caused by the second-order cross fractal structure. Distributions of surface current, electromagnetic field and power loss density are investigated to illustrate the absorptive characteristics and electromagnetic loss mechanisms of the proposed MMA. Moreover, the average optical transmittance of the MMA is close to 75% from 390 nm to 780 nm. The MMA possesses simultaneously strong absorptive capacity in the C-band and high transmittance in the visible light range, showing potential application in special environment.

Ti3C2 MXene is highly desirable as a potential microwave absorbent due to its positive dielectric loss ability. However, lack of magnetic loss for pure Ti3C2 MXene results in unbalanced electromagnetic parameters and poor impedance matching. In this paper, the laminated Ti3C2 MXene was synthesized using HF etching process. Then, the magnetic FeCo-decorated Ti3C2 MXene (FeCo-Ti3C2 MXene) composite was fabricated for the first time via a in-situ hydrothermal method. The incorporation of magnetic FeCo nanoparticles on Ti3C2 MXene can enhance microwave absorption property. Specifically, the FeCo-Ti3C2 MXene composite displayed a broad effective bandwidth (RL

The broadband nonlinear absorption in ZnO nanocrystals embedded in Al2O3 matrix was investigated by Z-scan and pump–probe techniques from 400 nm to 800 nm. The effective two-photon absorption and three-photon absorption coefficients were determined to be ∼1.1×103 cm/GW at 400 nm and ∼1.1×10−1 cm3/GW2 at 800 nm, respectively, which are at least two orders of magnitude greater than that in ZnO bulk crystal. It may be attributed to the defect-states-mediated multiphoton absorption process, which was proofed by comparison experiments with different densities of interfacial defect states. The corresponding lifetimes for the intraband relaxation, defect-states trapping, and interband recombination processes were measured by femtosecond transient absorption measurements as τ1 ∼ 1 ps, τ2 ∼ 13 ps, and τ3 ∼ 350 ps, respectively.