We show that in a source-free subwavelength region of microwave fields, there can exist field structures with a local coupling between the time-varying electric and magnetic fields differing from the electric-magnetic coupling in regular-propagating free-space electromagnetic waves. To distinguish such field structures from regular electromagnetic (EM) field structures, we term them as magnetoelectric (ME) fields. We study a structure and conservation laws of microwave ME near fields. We show that there exist sources of microwave ME near fields-the ME particles. These particles are represented by small quasi-two-dimensional ferrite disks with magnetic-dipolar-oscillation spectra. The near fields originating from such particles are characterized by topologically distinctive power-flow vortices, nonzero helicity, and a torsion degree of freedom. The paper consists of two main parts. In the first one, we give a theoretical background of properties of the electric and magnetic fields inside and outside of a ferrite particle with magnetic-dipolar-oscillation spectra resulting in the appearance of microwave ME near fields. In the second main part, we represent numerical and experimental studies of the microwave ME near fields and their interactions with matter. Based on the obtained properties of the ME near fields, we discuss possibilities for effective microwave sensing of natural and artificial chiral structures.
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http://dx.doi.org/10.1103/PhysRevE.87.023201 | DOI Listing |
Nanotechnology
January 2025
Institute of Nonlinear Optics, College of Science, JiuJiang University, Jiangxi 334000, People's Republic of China.
Titanium disulfide quantum dots (TiSQDs) has garnered significant research interest due to its distinctive electronic and optical properties. However, the effectiveness of TiSQDs in electromagnetic interference (EMI) shielding is influenced by various factors, including their size, morphology, monodispersity, tunable bandgap, Stokes shift and interfacial effects. In this study, we propose a systematic approach for the synthesis of TiSQDs with small size (3.
View Article and Find Full Text PDFTherapies against hematological malignancies using chimeric antigen receptors (CAR)-T cells have shown great potential; however, therapeutic success in solid tumors has been constrained due to limited tumor trafficking and infiltration, as well as the scarcity of cancer-specific solid tumor antigens. Therefore, the enrichment of tumor-antigen specific CAR-T cells in the desired region is critical for improving therapy efficacy and reducing systemic on-target/off-tumor side effects. Here, we functionalized human CAR-T cells with superparamagnetic iron oxide nanoparticles (SPIONs), making them magnetically controllable for site-directed targeting.
View Article and Find Full Text PDFRep Prog Phys
January 2025
School of Electrical Engineering, Xi'an Jiaotong University, School of Electrical Engineering, Xi'an Jiaotong University, Xi'an, Shaanxi, 710049, CHINA.
Parity-time symmetry is a fundamental concept in non-Hermitian physics that has recently gained attention for its potential in engineering advanced electronic systems and achieving robust wireless power transfer even in the presence of disturbances, through the incorporation of nonlinearity. However, the current parity-time-symmetric scheme falls short of achieving the theoretical maximum efficiency of wireless power transfer and faces challenges when applied to non-resistive loads. In this study, we propose a theoretical framework and provide experimental evidence demonstrating that asymmetric resonance, based on dispersive gain, can greatly enhance the efficiency of wireless power transfer beyond the limits of symmetric approaches.
View Article and Find Full Text PDFPLoS One
January 2025
Cnooc Information Technology Co., Ltd., Shenzhen, Guangdong, China.
A data transmission delay compensation algorithm for an interactive communication network of an offshore oil field operation scene in severe weather is proposed. To solve the problem of unstable microwave signals and a large amount of noise in the communication network caused by bad weather, the communication network signal denoising method based on Lagrange multiplier symplectic singular value mode decomposition is adopted, and the communication network data denoising process is realized through five steps; phase space reconstruction, symplectic geometric similarity transformation, grouping, diagonal averaging, and adaptive reconstruction. Simultaneously, the weak communication signal is compensated after being captured, that is, the characteristics of the weak signal are enhanced.
View Article and Find Full Text PDFAdv Mater
January 2025
National Key Laboratory of Microwave Photonics, Nanjing University of Aeronautics and Astronautics, Nanjing, 211106, China.
As one of the typical applications of metamaterials, the invisibility cloak has raised vast research interests. After many years' research efforts, the invisibility cloak has extended its applicability from optics and acoustics to electrostatics and thermal diffusion. One scientific challenge that has significantly restricted the practical application of the invisibility cloak is the strong background dependence, that is, all passive cloaking devices realized thus far are unable to resist variation in the background refractive index.
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