The porous hollow BaFe12O19/CoFe2O4 microrods were prepared by an easy and reproducible in situ synthetic method. Cotton cellulose was used as the sacrificial bio-template. The as-prepared hard/soft ...ferrite composites were homogeneously distributed on the surface of the microrods. It was demonstrated that the porous hollow microrods-like structure and the exchange-coupled interaction between hard and soft ferrites were beneficial to improve the microwave absorption properties. The weight content of the hard/soft ferrite composites was low to 60 wt%, whereas reflection loss could reach to −10 dB in the frequency range of 8.2–16.3 GHz. The fabrication of porous hollow BaFe12O19/CoFe2O4 microrods was an efficient approach to solve the heavy mass problem of the conventional hard/soft ferrite matrix microwave absorption materials.
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•A kind of novel porous hollow BaFe12O19/CoFe2O4 composite microrods was investigated.•The weight content of the hard/soft ferrite composites was less to 60 wt%.•The reflection loss was reach to −10 dB in the frequency range of 8.2–16.3 GHz.
Li-ion batteries are expected to become the mainstream devices for green energy storage or power supply in the future due to their advantages of high energy and power density and long cycle life. ...Monitoring the temperature and strain change characteristics of Li-ion batteries during operation is conducive to judging their safety performance. The hinged differential lever sensitization structure was used for strain sensitization in the design of an FBG sensor, which also allowed the simultaneous measurement of strain and temperature. The temperature and strain variation characteristics on the surface of a Li-ion soft-packed battery were measured using the des.igned sensor. This report found that the charging and discharging processes of Li-ion batteries are both exothermic processes, and exothermic heat release is greater when discharging than when charging. The strain on the surface of Li-ion batteries depends on electrochemical changes and thermal expansion effects during the charge and discharge processes. The charging process showed an increasing strain, and the discharging process showed a decreasing strain. Thermal expansion was found to be the primary cause of strain at high rates.
The expansion of urban construction areas can reduce the infiltration rate of rainwater in permeable land, and a large amount of runoff rainwater cannot penetrate the soil. In extreme rainstorm ...weather, it is easy to cause serious urban waterlogging problems. To improve the infiltration and decontamination ability of green space soil, two types of inorganic ameliorants (i.e., sand and grain shell) and structural ameliorants (i.e., desulfurization gypsum and polyacrylamide) were utilized as amendments in the soil. The influence of the selected ameliorants on the infiltration and decontamination ability was analyzed through a soil infiltration test, soil pore distribution determination and a soil decontamination test. Three parameters including the soil infiltration rate, pore distribution characteristics and pollutant removal rate were proposed. The results showed that sand, grain shells and desulfurization gypsum (FGD gypsum) all enhanced the infiltration capacity of soil, while PAM decreased the infiltration capacity. Meanwhile, mixed sand and grain shell with the FGD gypsum and polyacrylamide can effectively improve the decontamination capacity of the soil. Comprehensive analysis showed that the better improvement combination is 10% sand + 20% grain hull + 0.5 g/kg FGD gypsum + 0.1 g/kg PAM.
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•Effects of dislocation and SF on the performance of Si anode were revealed.•Si anode can be used for the storage of Na and Mg with the 30° partial dislocation.•Na and Mg may ...concentrate in the 30° partial dislocation core and SF region.•30° partial dislocation and SF may limit the charge/discharge rate of NIBs and MIBs.
While the perfect Si can’t be used to store Na and Mg interstitials in Na-ion batteries (NIBs) and Mg-ion batteries (MIBs), the defects of 30° partial dislocation and stacking fault (SF) may improve the performance of Si anode according to the multi-scale simulation results. It is found that both 30° partial dislocation and SF can provide more stable sites to accommodate impurities and enhance the binding strengths. The 30° partial dislocation can drastically promote the binding energies of Na (Mg) to the value of 0.72 (0.622)eV and 0.684 (0.6)eV at Oct-A and Oct-B, respectively. Moreover, it is thermodynamically and kinetically favorable for Na and Mg concentrating in the defect areas. On the other side, the migration barriers of Na and Mg in the 30° partial dislocation and SF are much higher than the defect-free Si. Those defects may restrict the diffusion of interstitials and turn into limiting factors of charge/discharge rate of NIBs and MIBs.
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•NiZn ferrite nanofibers was synthesized by the electrospinning method.•The reflection loss was less than −10dB in the whole X-band frequencies.•Microwave absorption mechanisms were ...detailed discussed.
In this paper, the NixZn(1−x)Fe2O4 (x=0.2, 0.4, 0.5, 0.6, 0.8) ferrite nanofibers were synthesized by electrospinning method. The microstructure, electromagnetic properties and microwave absorption mechanisms were analyzed (in detail). The results indicated that the nanofiber diameter, the saturation magnetization, the coercivity and the electromagnetic properties could be optimized by tuning the Ni2+ content. The Ni0.5Zn0.5Fe2O4 ferrite nanofiber finally performed the excellent microwave absorption properties. The reflection loss was less than −10dB in the whole X-band frequencies. The analysis of microwave absorption mechanism indicated that the microwave absorption bandwidth was mainly depended on the input impedance matching, the enhanced electromagnetic loss properties ensured that the entering wave could be mostly absorbed, and the frequency appearing the reflection loss peak was determined by the absorber thickness.
In this study, the flaky graphite/cobalt zinc ferrite composites were synthesized by the coprecipitation method. The XRD results showed that the flaky graphite/cobalt zinc ferrite composites can be ...obtained and there is no impurity when the graphite weight ratio is less than 20 wt%. The FE-SEM results exhibited that the flaky graphite/cobalt zinc ferrite composites possessed flake-like shape with high aspect ratio. Moreover, the electromagnetic properties could be tuned by varying the graphite weight ratio. In the series of as-prepared flaky graphite/cobalt zinc ferrite composites, the sample with 10 wt% graphite possessed excellent impedance matching performance. As a result, the it exhibited the best microwave absorption properties. The reflection loss was less than −10 dB in frequency range of 10.3–13.5 GHz and the maximum reflection loss was reach to −33.85 dB at 11.7 GHz when the coating thickness was 2.5 mm. Moreover, the electromagnetic analysis demonstrated that the electromagnetic loss properties and the electromagnetic impedance matching performance should be both satisfied to obtain the excellent microwave absorption properties. This study was meaningful to design the ferrite/carbon composites based microwave absorbers.
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•Flaky graphite/cobalt zinc ferrite composites were synthesized.•The microwave absorption mechanism was discussed.•Tunable electromagnetic properties and enhanced microwave absorption properties.•It is significant to design ferrite/carbon composites as microwave absorber.
The ZnFe2O4 ferrite nanoparticle and nanofiber were synthesized by electrospinning method. The phase composition, morphology, magnetic and electromagnetic properties were analyzed. The results showed ...that both the samples exhibited a pure phase of spinel type ferrite. The ZnFe2O4 ferrite nanoparticle was aggregated, while the ZnFe2O4 ferrite nanofiber performed the homogeneous nano-fibrous shape as well as single-particle-chain structure. The magnetic analysis indicated that the ZnFe2O4 ferrite nanofiber showed ferromagnetic behaviour. Moreover, the dielectric loss and magnetic loss properties of ZnFe2O4 ferrite nanofiber were both enhanced due to its better dipole polarization, interfacial polarization and shape anisotropy.
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•The ZnFe2O4 ferrite nanoparticle and nanofiber were synthesized by the electrospinning method.•The ZnFe2O4 ferrite nanofiber performed the homogeneous nano-fibrous shape as well as single-particle-chain structure.•The ZnFe2O4 ferrite nanofiber behaved as the ferromagnetic property.•The dielectric loss and magnetic loss properties of ZnFe2O4 ferrite nanofiber were both enhanced.
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•Firstly, TiO2-Doped GeSe Monolayer are studied.•The introduction of dopants improves the selectivity and sensitivity of GeSe.•Doped GeSe have suitable sensing traits to perfect ...adsorption and desorption.•The change of conductivity is critical to production of resistive gas sensors.
The detection of SF6 decomposition species has been a crucial method of fault diagnosis for insulation equipment. Faced with problems of poor selectivity, low sensitivity and non-recyclability of existing nano-gas sensors, TiO2-doped GeSe monolayer is proposed. The doping of TiO2 nanoparticle greatly improves the conductivity of GeSe monolayer and the selective for SF6 decomposition species, SO2 > H2S > SOF2 > SO2F2. Moreover, electron transfer of SF6 is further inhibited. When gases are adsorbed, the reduction of the difficulty of electron transition ensures the high sensitivity detection in practical application, especially SO2. Ideal adsorption energies ensure that TiO2-GeSe monolayer has excellent response and recovery ability, which theoretically solves the industrial problem of recycling. In addition, compared with pure GeSe and other normal 2D materials, TiO2-GeSe exhibits excellent sensing detection advantages. This study provides a theoretical foundation for resistive chemical sensors used in industrial insulation equipment.
Rapid oxygen ion conduction, which is important in solid oxide fuel cell (SOFC) electrolytes, is often dramatically hindered by the presence of even small concentrations of impurities such as SiO2, ...which is ubiquitous in ceramic processing. In this study, rapid degradation of the grain boundary (GB) conduction of Ce0.8Sm0.2O1.9 (SDC) is observed with increasing SiO2 addition from 0 to 1 wt%. Nearly complete GB conduction recovery is achieved through synergy between CaO and ZnO in the SDC + x wt% Si systems. Scanning electron microscopy (SEM) combined with energy dispersive spectroscopy (EDS) demonstrate the formation of a Ca-, Si-, and Sm-containing secondary phases, which is related to the enhancements in GB conductivity and reductions in activation energy. The scavenging effect of CaO is verified in this study and ZnO is observed to promote the scavenging reaction. Compared with the single-addition case (CaO/ZnO), the much higher SiO2 impurity tolerance of the combined system suggests the commercial potential of the “scavenger + promoter” strategy presented in this work.
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•CaO and ZnO co-doping is effective against various degrees of Si contamination.•SEM-EDS reveal the formation of a Ca-, Si-, and Sm-containing secondary phase.•CaO acts as a scavenger for Si impurity and ZnO can promote the scavenging process.
