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The plasma sheath causes the spacecraft’s communication signal to attenuate dramatically during the re-entry period, which seriously threatens the astronauts. However, valid experimental protocols have not been obtained hitherto. To realize the propagation of electromagnetic waves in negative permittivity background of the plasma sheath, alumina columns are embedded in the plasma background to form plasma photonic crystals, which can support the coupling of evanescent waves between the alumina columns. We experimentally demonstrate the realization of communication in blackout scenario by achieving a complete passing band in the plasma cutoff region. For high frequency communications in the plasma sheath, electromagnetic wave propagation based on topological edge states is also experimentally demonstrated. Furthermore, we realize a triply-degenerate Dirac cone formed dynamically at the center of the Brillouin zone by modulating the electron density, where electromagnetic wave exhibits high transmittance and does not experience phase accumulation at the Dirac point. Our work thus not only provides an effective approach to overcome the communication blackout problem, but the design can also be served as a promising experimental platform to explore topological electromagnetic phenomena.

Consistent c-axis orientation characteristics toward the direction of applied pressure of Y-type BaSrCo2Fe11AlO22 (BSCFAO-θ) were successfully prepared by the strategy of hot pressing. The samples' magnetoelectric coupling performance was greatly enhanced by the strategy of hot pressing than that of the traditional solid reaction method. The magnetoelectric current of BSCFAO-θ (θ = 0°) (12.06 μA/m2) was nearly 5 times higher than BSCFAO-SS (2.24 μA/m2). The magnetoelectric polarization of BSCFAO-θ (θ = 0°) (32.82 μC/m2) was nearly 4 times higher than that of BSCFAO-SS (8.31 μC/m2). The magnetoelectric coupling coefficients of BSCFAO-θ (θ = 0°) (1880 ps/m) were nearly 4 times higher than those of BSCFAO-SS (404 ps/m). The enhancement of magnetoelectric polarization of BSCFAO-θ (θ = 0°) can be attributed to the uniform c-axis orientation, which reinforced magnetoelectric polarization compared with none orientation that eliminated the magnetoelectric polarization on grain boundaries. The magnetoelectric coupling performance of BSCFAO-θ presented a gradually decreasing trend with the angle changing from 0° to 90° for the changing of orientation. Compared with traditional solid reaction methods, the strategy of hot pressing inhibits grain growth and increases grain boundaries, thus facilitating the enhancement of grain boundaries' resistivity, and the electrical resistivity of BSCFAO-θ (3.08 × 1010 Ω cm) was nearly 10 000 times higher than that of BSCFAO-SS (2.5 × 106 Ω cm), which also benefits the magnetoelectric polarization performance of BSCFAO-θ. Therefore, the hot-pressing strategy can contribute to the forming of oriented ceramics and enhance the grain boundaries' resistivity to improve magnetoelectric coupling performance. [ABSTRACT FROM AUTHOR]

Most theoretically predicted and experimentally confirmed quantum spin Hall effects (QSHEs) are limited to zero-moment magnets. In this study, we theoretically anticipate the QSHE in ferromagnets and the quantum anomalous Hall effect (QAHE) in antiferromagnets through van der Waals stacked layers, where the magnetization direction is confined to the in-plane. We introduce a search rule for constructing ferromagnetic (FM) quantum spin Hall insulator (QSHI) and antiferromagnetic (AFM) quantum anomalous Hall insulator (QAHI) and further predict a real material of the LuN2/GaS/LuN2 van der Waals multilayer by first-principles calculations. Our results demonstrate the superposition and elimination of Chern numbers under mirror symmetry and time-reversal symmetry, and they further indicate that FM QSHI and AFM QAHI can be converted through deflection magnetization. These findings broaden the material class for QSHE and QAHE and propose a scheme for constructing FM QSHI and AFM QAHI. [ABSTRACT FROM AUTHOR]

A sub-wavelength particle with a total scattering cross section that exceeds the single channel limit is referred to as a superscatterer, which can provide ability to control light in nanoscale. A variety of superscatter structures have been suggested, most of them are typically constructed with strong forward scattering but minor backscattering. This unusual behavior can be attributed to the superposition of resonant modes in adjacent angular momentum channels. We reveal the mechanism of super backscattering for subwavelength column, which can be formed by recombining non-adjacent resonant modes, as confirmed by our numerical analysis. [ABSTRACT FROM AUTHOR]

In this work, emission spectra measurements from direct current (DC) reverse‐brush discharge plasmas were used to elucidate the energy level transition processes corresponding to each spectral line based on the mechanism of emission spectrum generation. The axial distribution patterns of the spectral line intensity and the electron excitation temperature in the electrode gap and post‐cathode space were systematically investigated. By comparing the acquired experimental results, it was observed that both the relative intensity of the plasma emission spectra and the electron excitation temperature in the electrode gap were higher than in the post‐cathode space, while their axial distribution trends exhibited an initial increase followed by a decrease. Additionally, the impact of the discharge gas pressure, reverse‐brush electrode thickness, and the number of electrode openings on the emission spectral line intensity and electron excitation temperature in the electrode gap were explored. Explanations for the underlying physical mechanisms were also provided. [ABSTRACT FROM AUTHOR]

Zinc is a critical trace element in the human body, playing a key role in regulating various protein functions and cellular metabolism. Thus, maintaining zinc homeostasis is essential for human health, as zinc deficiency can directly contribute to the onset of numerous diseases. Effective supplementation with zinc ions offers a viable treatment for zinc deficiency. Polysaccharides, particularly natural polysaccharides, exhibit extensive physiological activities and serve as efficient systems for delivering zinc ions. Fucoidan (F) is an affordable, widely available polysaccharide with significant bioactivity and safety, attracting growing research interest. However, most studies focus on its physiological functions, while few explore the structure and effects of fucoidan–metal complexes. In this study, fucoidan (F) was chosen to complex with Zn2+ to form the fucoidan–zinc (F–Zn) complex, whose structure was characterized. The zinc ion content reached 9.15%, with zinc (II) predominantly complexed with sulfate groups in the F–Zn (II) complex. Evaluation demonstrated that the prepared fucoidan–zinc system, at a concentration of 110 μg/ml, exhibited no significant cytotoxicity toward HT22 cells. Furthermore, both F and F–Zn exhibited significant neuroprotective effects in an HT22 cell model induced by cisplatin. Additional investigations revealed that F and F–Zn could mitigate cisplatin-induced increases in reactive oxygen species levels and alleviate mitochondrial damage. The fucoidan–zinc complex presents itself as a promising zinc ion delivery system for treating zinc deficiency. [ABSTRACT FROM AUTHOR]