In this study, we successfully prepared core–shell heterostructured nanocomposites (Fe NWs@SiO2), with ferromagnetic nanowires (Fe NWs) as the core and silica (SiO2) as the shell. The composites exhibited enhanced electromagnetic wave absorption and oxidation resistance and were synthesized using a simple liquid-phase hydrolysis reaction. We tested and analyzed the microwave absorption properties of Fe NWs@SiO2 composites with varied filling rates (mass fractions of 10 wt%, 30 wt%, and 50 wt% after mixing with paraffin). The results showed that the sample filled with 50 wt% had the best comprehensive performance. At the matching thickness of 7.25 mm, the minimum reflection loss (RLmin) could reach −54.88 dB at 13.52 GHz and the effective absorption bandwidth (EAB, RL < −10 dB) could reach 2.88 GHz in the range of 8.96–17.12 GHz. Enhanced microwave absorption performance of the core–shell structured Fe NWs@SiO2 composites could be attributed to the magnetic loss of the composite, the core–shell heterogeneous interface polarization effect, and the small-scale effect induced by the one-dimensional structure. Theoretically, this research provided Fe NWs@SiO2 composites with highly absorbent and antioxidant core–shell structures for future practical applications.
Autonomous obstacle avoidance and decision-making algorithms for intelligent connected vehicles in a complicated transportation environment are important studies on intelligent driving. However, it is difficult to adapt to a more complicated traffic environment based on safety distance and conventional potential field. Therefore, in this paper, a driving risk field model based on field theory is proposed involving transportation factors and vehicle conditions. A hidden Markov model was used to evaluate and determine the motion state of surrounding vehicles. A safe, feasible, and smooth collision-free path was planned by calculating the magnitude of the potential field forces on the longitudinal and lateral sides of the obstacle vehicles. The results showed that the method can effectively select a suitable path for obstacle avoidance in complex road conditions while satisfying safety and traffic laws.
One-dimensional iron–nickel (Fe–Ni) heterogeneous
nanowires with superior electromagnetic wave (EMW) absorption were
successfully prepared by a magnetic-field-assisted liquid-phase reduction
method. The electromagnetic properties of the absorber were controllably
tuned by changing the atomic molar ratio of Fe to Ni. The composite
with an Fe:Ni atomic molar ratio of 1:1.5 exhibited the finest EMW
absorption characteristics. With a matched thickness of 2.175 mm,
the minimum reflection loss (RLmin) at 18 GHz can be as
high as 26.106 dB. Also, the majority of the Ku-band is covered by
the effective absorption bandwidth (EAB, RL ≤ −10 dB),
which is up to 6.08 GHz at 2.6 mm with a filler content of 25%. The
excellent absorber performance is due to one’s own rich heterogeneous
interface to conciliate the dielectric and magnetic losses. The successful
exploration of the one-dimensional heterogeneous structure EMW absorber
provides important insights for the future sensible fabrication of
absorbers with excellent EMW absorption capability.
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