Electromagnetic Fields

Geomagnetic field (GMF) protects living organisms on the Earth from the radiation coming from space along with other environmental factors during evolution, and it has affected the growth and development of plants. Many researchers have always been interested in investigating these effects in different aspects. In this chapter, we focus on the methods of using different types of magnetic fields (MFs) to investigate the dimensions of their biological effects on plants. The aim is to increase seed germination, growth characters, and yield of plants using the following methods: (1) Using MFs lower than GMF to study effects of GMF on the growth and yield of plants...

The design and preparation of flexible aerogel materials with high deformability and versatility have become an emerging research topic in the aerogel fields, as the brittle nature of traditional aerogels severely affects their safety and reliability in use. Herein, we review the preparation methods and properties of flexible aerogels and summarize the various controlling and design methods of aerogels to overcome the fragility caused by high porosity and nanoporous network structure. The mechanical flexibility of aerogels can be revolutionarily improved by monomer regulation, nanofiber assembly, structural design and controlling, and constructing of aerogel composites, which can greatly broaden the multifunctionality and practical application prospects...

Infrared thermal imaging is a passive non-contact detection and identification technology, which is not subject to electromagnetic infection and good concealment, is widely used in military and commercial fields. However, due to the limitations of the existing infrared imaging system mechanisms, the spatial resolution of the acquired infrared images is low and the edge details are blurred, which in turn leads to poor performance in downstream missions based on infrared images. In this paper, in order to better solve the above problems, we propose a new super-resolution reconstruction framework for infrared images, called DBFE, which extracts and retains abundant structure and textual information for robust infrared image high-resolution reconstruction with a novel structure-textual encoder module...

Nanophotonic devices excel at confining light into intense hot spots of electromagnetic near fields, creating exceptional opportunities for light-matter coupling and surface-enhanced sensing. Recently, all-dielectric metasurfaces with ultrasharp resonances enabled by photonic bound states in the continuum (BICs) have unlocked additional functionalities for surface-enhanced biospectroscopy by precisely targeting and reading out the molecular absorption signatures of diverse molecular systems. However, BIC-driven molecular spectroscopy has so far focused on end point measurements in dry conditions, neglecting the crucial interaction dynamics of biological systems...

There are numerous effective procedures for cell signaling, in which humans directly transmit detectable signals to cells to govern their essential behaviors. From a biomedical perspective, the cellular response to the combined influence of electrical and magnetic fields holds significant promise in various domains, such as cancer treatment, targeted drug delivery, gene therapy, and wound healing. Among these modern cell signaling methods, electromagnetic fields (EMFs) play a pivotal role; however, there remains a paucity of knowledge concerning the effects of EMFs across all wavelengths...

We propose a structurally simple, innovative, and multifunctional mid-infrared broadband thermally tunable metamaterial absorption device. The absorption device consists of a three-layer structure, from bottom to top: Ti substrate, SiO2 dielectric layer, and patterned VO2 layer. Through temperature control, the average absorption intensity of the absorption device can vary between 0.08 and 0.94. The absorption device's absorption mechanism is rooted in the thermal phase-change characteristics exhibited by the topologically patterned VO2 ...

STUDY DESIGN: A prospective multicenter clinical trial (NCT03177473) was conducted with a retrospective cohort used as a control arm. OBJECTIVE: The purpose of this study was to evaluate cervical spine fusion rates in subjects with risk factors for pseudarthrosis who received pulsed electromagnetic field (PEMF) treatment. SUMMARY OF BACKGROUND DATA: Certain risk factors predispose patients to pseudarthrosis, which is associated with prolonged pain, reduced function, and decreased quality of life...

PURPOSE: We examined magnetic field dependent SNR gains and ability to capture them with multichannel receive arrays for human head imaging in going from 7 T, the most commonly used ultrahigh magnetic field (UHF) platform at the present, to 10.5 T, which represents the emerging new frontier of >10 T in UHFs. METHODS: Electromagnetic (EM) models of 31-channel and 63-channel multichannel arrays built for 10.5 T were developed for 10...

Topological spin textures are characterized by magnetic topological charges, Q, which govern their electromagnetic properties. Recent studies have achieved skyrmion bundles with arbitrary integer values of Q, opening possibilities for exploring topological spintronics based on Q. However, the realization of stable skyrmion bundles in chiral magnets at room temperature and zero magnetic field - the prerequisite for realistic device applications - has remained elusive. Here, through the combination of pulsed currents and reversed magnetic fields, we experimentally achieve skyrmion bundles with different integer Q values - reaching a maximum of 24 at above room temperature and zero magnetic field - in the chiral magnet Co8 Zn10 Mn2 ...

The utilization of electromagnetic waves is rapidly advancing into the millimeter-wave frequency range, posing increasingly severe challenges in terms of electromagnetic pollution prevention and radar stealth. However, existing millimeter-wave absorbers are still inadequate in addressing these issues due to their monotonous magnetic resonance pattern. In this work, rare-earth La3+ and non-magnetic Zr4+ ions are simultaneously incorporated into M-type barium ferrite (BaM) to intentionally manipulate the multi-magnetic resonance behavior...

The electric field gradient (EFG) has the potential to control both the direction and energy levels of nuclear spins greater than 1/2, a phenomenon known as nuclear electric resonance. Sodium ions on phospholipid membranes, having a nuclear spin of 3/2, can be influenced by surrounding EFGs. Driven by the complex behavior of anisotropic rotation and diffusion of phospholipid molecules, we conducted theoretical investigations and molecular dynamics simulations to study the characteristics of the EFG in this unique environment...

The intensity and sensitivity of surface-enhanced Raman scattering (SERS) spectra are highly dependent on the consistency and homogeneity of the nanomaterials. In this study, we developed a large-area three-dimensional (3D) hotspot substrate with good homogeneity and reproducibility in SERS signals. The substrate is based on the synergistic structures of nanoporous gold (NPG) and gold nanoparticles (AuNPs). NPG was combined with a periodic V-shaped nanocavity array to create nanoporous gold with a V-cavity (NPGVC) array featuring uniform hotspots...

UNLABELLED: Across all electrical stimulation (neuromodulation) domains, conventional analysis of cell polarization involves two discrete steps: i) prediction of macroscopic electric field, ignoring presence of cells and; ii) prediction of cell polarization from tissue electric fields. The first step assumes that electric current flow is not distorted by the dense tortuous network of cell structures. The deficiencies of this assumption have long been recognized, but - except for trivial geometries - ignored, because it presented intractable computation hurdles...

BACKGROUND: The technological applications of radiofrequency electromagnetic fields (RF-EMF) have been steadily increasing since the 1950s exposing large proportions of the population. The World Health Organization (WHO) is assessing the potential health effects of exposure to RF-EMF. OBJECTIVES: To systematically assess the effects of exposure to RF-EMF on self-reported non-specific symptoms in human subjects and to assess the accuracy of perceptions of presence or absence of RF-EMF exposure...

Near-field radiative heat transfer has recently attracted increasing interests for its applications in energy technologies, such as thermophotovoltaics. Existing works, however, are restricted to time-independent systems. Here, we explore near-field radiative heat transfer between two bodies under time modulation by developing a rigorous fluctuational electrodynamics formalism. We demonstrate that time modulation can result in the enhancement, suppression, elimination, or reversal of radiative heat flow between the two bodies, and can be used to create a radiative thermal diode with an infinite contrast ratio, as well as a near-field radiative heat engine that pumps heat from the cold to the hot bodies...

Active terahertz metasurface devices have been widely used in communication technology, optical computing and biosensing. However, numerous dynamically tunable metasurfaces are only operating at a single frequency point or in a narrow range, limiting the further possibility of the devices to meet contemporary broad-spectrum biosensing requirements. In this paper, a novel compact biosensor is proposed with an ultrawide resonance frequency agile channel shifted from 0.82 to 1.85 THz, with a tuning functionality up to 55...

Hypertension is a major preventable risk factor for cardiovascular disease. This review evaluates the effects of pulsed electromagnetic field (PEMF) therapy and aerobic exercise on blood pressure (BP) levels in hypertensive patients. This study incorporated research conducted between 2012 and 2020 that was found through a systematic literature search. The measures used to estimate the improvement in BP include the BP measurements, quality-of-life (QOL) scale, and plasma nitric oxide (NO) level. The examination of the review comprised eight studies...

Plasmon enhanced fluorescent (PEF) with more "hot spots" play a critical role in signal amplified technology to avoid the intrinsic limitation of fluorophore which ascribed to a strong electromagnetic field at the tip structure. However, application of PEF technique to obtain a highly sensitive analysis of medicine was still at a very early stage. Herein, a simple but versatile Ag nanocubes (Agcubes)-based PEF sensor combined with aptamer (Agcubes@SiO2 -QDs-Apt) was proposed for highly sensitive detection of berberine hydrochloride (BH)...

Electron cyclotron resonance heating method of Particle-in-Cell code was used to analyze heating phenomena, axial kinetic energy, and self-consistent electric field of confined electron plasma in ELTRAP device by hydrogen and helium background gases. The electromagnetic simulations were performed at a constant power of 3.8 V for different RF drives (0.5 GHz- 8 GHz), as well as for 1 GHz constant frequency at these varying amplitudes (1 V-3.8 V). The impacts of axial and radial temperatures were found maximum at 1...

Differential phase contrast scanning transmission electron microscopy (DPC STEM) is a powerful technique for directly visualizing electromagnetic fields inside materials at high spatial resolution. Electric field observation within ferroelectric materials is potentially possible by DPC STEM, but concomitant diffraction contrast hinders the quantitative electric field evaluation. Diffraction contrast is basically caused by the diffraction-condition variation inside a field-of-view, but in the case of ferroelectric materials, the diffraction conditions can also change with respect to the polarization orientations...