We present a formulation of molecular response theory for the description of a quantum mechanical molecular system in the presence of a weak, monochromatic, linearly polarized electromagnetic field ...without introducing truncated multipolar expansions. The presentation focuses on a description of linear absorption by adopting the energy-loss approach in combination with the complex polarization propagator formulation of response theory. Going beyond the electric-dipole approximation is essential whenever studying electric-dipole-forbidden transitions, and in general, non-dipolar effects become increasingly important when addressing spectroscopies involving higher-energy photons. These two aspects are examined by our study of the near K-edge X-ray absorption fine structure of the alkaline earth metals (Mg, Ca, Sr, Ba, and Ra) as well as the trans-polyenes. In following the series of alkaline earth metals, the sizes of non-dipolar effects are probed with respect to increasing photon energies and a detailed assessment of results is made in terms of studying the pertinent transition electron densities and in particular their spatial extension in comparison with the photon wavelength. Along the series of trans-polyenes, the sizes of non-dipolar effects are probed for X-ray spectroscopies on organic molecules with respect to the spatial extension of the chromophore.
In this paper, we introduce the basic principles of wireless power transfer using magnetic field resonance and describe techniques for the design of a resonant magnetic coil, the formation of a ...magnetic field distribution, and electromagnetic field (EMF) noise suppression methods. The experimental results of wireless power transfer systems in consumer electronics applications are discussed in terms of issues related to their efficiency and EMF noise. Furthermore, we present a passive shielding method and a magnetic field cancellation method using a reactive resonant current loop and the utilization of these methods in an online electric vehicle (OLEV) system, in which an OLEV green transportation bus system absorbs wireless power from power cables underneath the road surface with only a minimal battery capacity.
A key limitation inherent in wireless power transmission (WPT) systems using coils is a high sensitivity to the alignment between the transmitting and receiving coils. Moreover, the physical ...separation of the transmitting and receiving coils or any metallic barrier between them can notably reduce the efficiency. To overcome these limitations, a practical WPT system that is insensitive to the alignment between coils and metallic obstacles is proposed. It uses a printed circuit board-type antenna fabricated by reducing the structure of an antenna used in previous research and is designed to resonate at the target frequency through impedance matching. The proposed system uses surface-guided-mode resonance at the metal–air interface and transmits uniform power within 1.3 m. In addition, the proposed system satisfies the electromagnetic field international standard that is the electric field and magnetic field reference values are 152.5 V/m and 0.4 A/m, respectively at 4 MHz.
Purpose: The goal of this work is to investigate the anticancer potency of magnetically induced muscle secretome on breast cancer in vitro, in vivo and ex vitro. The work also examines the function ...of magnetically mediated preconditioning paradigm to enhance muscle secretome release and production.
Briefly (10 min) exposing C2C12 myotubes to low amplitude (1.5 milliTesla) pulsed electromagnetic fields (PEMFs) generated a conditioned media (pCM) that mitigated breast cancer cell growth, migration and invasiveness in vitro, whereas the conditioned media harvested from unexposed myotubes, representing constitutively released secretome (cCM), was less effective. Ex vivo, administering pCM to breast cancer microtumors engrafted onto the chorioallantoic membrane of the chicken egg reduced tumor volume and vascularity. In vivo, blood serum collected from PEMF-exposed or exercised mice allayed breast cancer cell growth, migration and invasiveness. Based on PEMF-induction of the muscle secretome, a preconditioning methodology was developed to enhance secretome production and release. HTRA1 (High-Temperature Requirement A Serine Peptidase 1) was upregulated in the pCM and was shown necessary for myogenic progression and anticancer potency. HTRA1 expression hence embodied key adaptive features of the pCM preconditioning paradigm and emulating an exercise-like effect. Brief and non-invasive PEMF stimulation may represent a method to commandeer the secretome response of muscle for clinical exploitation in cancer.
Brief and non-invasive pulsed electromagnetic field (PEMF) stimulation was shown to induce the secretome response of muscles akin to exercise to impact cancer viability and epithelial-mesenchymal transition (EMT). Moreover, the preconditioning of cells to PEMF may represent a method to induce the secretome response of muscles for clinical exploitation in cancer.
Introduction: Low-frequency electromagnetic field (50 Hz) (EMF) can modify crucial neuronal processes. Existing data indicate that exposure to EMF may represent a mild stressor and contribute to ...disturbances of the hypothalamic-pituitary-adrenal (HPA) axis. The important regulatory pathways controlling HPA axis activity include two types of corticosteroid receptors: mineralocorticoid receptors (MRs) and glucocorticoid receptors. They are particularly abundant in the hippocampus, a key locus of HPA axis feedback control. The research aimed at determining whether (1) EMF exhibits hormesis, it means bidirectional action depending on EMF intensity (1 or 7 mT) and (2) repeated EMF exposure changes stress response to subsequent stress factors. Methods: The exposure (7 days, 1 h/day) of adult rats to EMF (1 mT and 7 mT) was repeated 3 times. HPA axis hormones and their receptors were analysed after each following exposure. Moreover, the impact of EMF exposure on hormonal and behavioural responses to subsequent stress factor – open-field test was evaluated. Results: Our data suggest that exposure to EMF can establish a new “set-point” for HPA axis activity. The direction and dynamics of this process depend on the intensity of EMF and the number of exposures. EMF of 1 mT induced an adaptive stress response, but 7 mT EMF caused sensitization. Consequently, EMF changed the vulnerability of the organism to a subsequent stress factor. We have also shown the increase in MR mRNA abundance in the hippocampus of 1 mT EMF-exposed rats, which can represent the possible neuroprotective response and suggest therapeutic properties of EMFs.
The air-cooled turbo-generator often works in the more frequent start-up and shut-down operation. Either the misoperation or the failure of synchronizing controllers can cause the out of phase ...synchronization fault. The fault can disturb the power angle and cause a strong impact electromagnetic force for the generator. With the traditional numerical calculation method, it is difficult to calculate the variations of key physical parameters and the electromagnetic field in the end region of the generator under complex working conditions, especially the out of phase synchronization fault. In order to solve the problem, a calculation method of the nonlinear transient electromagnetic field with multi-domain field-circuit-grid coupled is proposed. The correctness of the model and method is validated by comparing the calculated and test values of the magnetic density flux at the key points of the generator under the no-load condition. Based on this method, the power angle variation, the magnetic flux leakage distribution in the end region, and the electromagnetic force on the end winding in the transient process of the fault are calculated and analyzed.
Magnetically coupled resonance wireless power transfer systems (MCR WPT) have been developed in recent years. There are several key benefits of such systems, including dispensing with power cords, ...being able to charge multiple devices simultaneously, and having a wide power range. Hence, WPT systems have been used to supply the power for many applications, such as electric vehicles (EVs), implantable medical devices (IMDs), consumer electronics, etc. The literature has reported numerous topologies, many structures with misalignment effects, and various standards related to WPT systems; they are usually confusing and difficult to follow. To provide a clearer picture, this paper aims to provide comprehensive classifications for the recent contributions to the current state of MCR WPT. This paper sets a benchmark in order to provide a deep comparison between different WPT systems according to different criteria: (1) compensation topologies; (2) resonator structures with misalignment effects; and, (3) electromagnetic field (EMF) diagnostics and electromagnetic field interference (EMI), including the WPT-related standards and EMI and EMF reduction methods. Finally, WPT systems are arranged according to the application type. In addition, a WPT case study is proposed, an algorithm design is given, and experiments are conducted to validate the results obtained by simulations.
Potential trends in the intensity and irregularity of the Earth's natural pulse electromagnetic field (ENPEMF) signal may be related to the occurrence of seismic hazards. To investigate this ...potential variation trend, radial basis function (RBF) forecast models have been applied in the field of ENPEMF signal intensity forecast, but its forecast accuracy is not high enough to be used in the field of seismic hazard monitoring and other fields that require high accuracy. In addition, although the rapid development of deep learning has improved the accuracy of time series forecasts, ENPEMF signals are susceptible to noise, which may lead to erroneous identification of pregnant earthquake information. Based on this, this article proposes a chaotic long short-term memory (LSTM) forecasting model based on fractional Fourier transform (FrFT) optimized VMD (FrVMD) to forecast the underlying ENPEMF signal intensity trend. The strategy of the proposed model is the FrVMD algorithm to decompose and reconstruct the original signal for noise reduction, whereupon forecasting the phase space reconstructed ENPEMF data by chaotic parameters optimizing the LSTM network. The model of this article is applied to the ENPEMF signal before and after the Ms7.0 magnitude earthquake in Lushan on April 20, 2013. The numerical results show that the proposed model forecasts the intensity trend of ENPEMF data more accurately, for the forecast effect and accuracy are better than the traditional RBF network, chaotic RBF network, and traditional LSTM network model, which helps to identify the pregnant earthquake information and provides support for electromagnetic monitoring analysis before geological disasters and strong earthquakes.
Display omitted
•Terahertz electromagnetic fields are effective in promoting the hydrates formation.•Terahertz fields induce water molecules rearrangement by resonance with water.•Reducing IFT and ...enhancing gas solubility can accelerate hydrate formation.•The pathway of hydrate formation is regulated by methane solubility.
The low solubility of methane in water and the formation of hydrate film at methane-water interface restrict interfacial mass transfer between methane and water, thereby impeding the rapid formation of hydrate. Herein, THz electromagnetic field (TEMF) is introduced to destroy hydrogen bonds through resonance with water molecules for decreasing methane-water interfacial tension (IFT) and improving methane solubility in water. Thereafter, TEMF is removed to restore hydrogen bonding interaction for hydrate nucleation within bulk-phase water rather than at methane-water interface, thereby accelerating hydrate formation. The results show that a TEMF at 15.8 THz can increase methane solubility by 50-fold and provide more nucleation sites for hydrate formation by lowering the IFT by 15-fold. Furthermore, the hydrate nucleation follows “blob” nucleation at low solubility and Local Structuring Mechanism nucleation at high solubility. The higher solubility of methane shortens the induction period of hydrate nucleation form 58.5 ns to 29 ns. Particularly, small 512 cages form preferentially regardless of nucleation pathway. The underlying mechanism for TEMF-induced the acceleration of hydrate formation is attributed to the transition of water phase from a disordered to an ordered structure. This transition arises from the resonance of the TEMF with water molecules, disrupting the hydrogen bond between water molecules and providing sufficient driving force for their rearrangement after removing the TEMF. In rearrangement process, weakly hydrogen-bond interactions correspondingly are converted into strongly hydrogen-bond ones. These findings are expected to improve the understanding of hydrate formation mechanism and promote the applications of terahertz technology in gas hydrates.
PDF
