Peripheral such as aerospace, armor, sensors, heat exchanger, automobile, storage, and any other electronic equipment are frequently subjected to varying mechanical and thermal stress, which ...substantially influence their reliability, life cycle, and performance. The aerospace sector, for example, is in constant research for the decrement in mass to achieve higher fuel efficiency through light weighting approach. It is due to the specific parameters that advanced polymer composites exhibit, there are growing research interests in heat management schemes, where both higher thermal characteristics and strength with significantly lower density are simultaneously essential. In the same manner, nanohybrid particles are commonly utilized as reinforcement fillers to enhance mechanical, electromagnetic shielding efficiency, and thermal characteristics of any polymer matrices. This survey discusses the polymer‐based nanocomposites incorporated with hybrid nanoparticles for applications in high‐performance materials. The subsequent interaction between the selected polymer matrix and hybrid nanofillers, which affects the characteristics of the polymer‐based nanocomposites: mechanical, electromagnetic radiation shielding efficiency as well as thermal conductivity have been critically reviewed. The hybrid nanoparticles' synergy facilitates effective dispersion without damaging the structures of the nanofillers tend to optimized electrical properties, thermal conductivity, and higher overall functionality of the fabricated nanocomposites.
The time derivative of a charge density is linked to a current density by the continuity equation. However, it features only the longitudinal part of a current density, which is known to produce no ...radiation. This fact usually remains unnoticed and may appear puzzling at first, suggesting that the temporal variation of a charge density should be also irrelevant to radiation. We alleviate the apparent contradiction by showing that the effective longitudinal currents are not spatially confined, even when the time-dependent radiating charge density that generates them is. This enforces the co-existence of the complementary, i.e. transverse, part of the current, which, in turn, gives rise to radiation. We illustrate the necessarily delocalized nature and relevance of longitudinal currents to the emission of electromagnetic waves by a dynamic electric dipole, discussing the practical implications of that for radation in partially conducting condensed matter. More generally, we show how the connection between the longitudinal and transverse currents shapes the structure of the conventional multipole expansion and fuels the ongoing confusion surrounding the charge and toroidal multipoles.
We propose a quantum metrology protocol for the localization of a noncooperative pointlike target in three-dimensional space, by illuminating it with electromagnetic waves. It employs all the spatial ...degrees of freedom of N entangled photons to achieve an uncertainty in localization that is N times smaller for each spatial direction than what could be achieved by N-independent photons or by classical light of the same average intensity.
The current work presents the fabrication of micrometer‐thick single‐side‐coated surface‐engineered polypropylene (PP) film for versatile flexible electronics applications. Herein, the authors ...report, for the first time, photopolymerized thin coating of graphene nanofibers (GNFs) and iron oxide nanoparticles (IONPs) onto non‐polar plastic via surface chemistry. The fabrication is achieved by adopting three consecutive steps; initially corona treated PP films are treated with silane for thin layer silica coating. Then, the silylated PP films are brushed up by pyrrole/GNFs/IONPs mixture, followed by UV exposure. The coated films show surface conductivity in the range of ≈20 S cm−1 at room temperature. Moreover, ≈15 microns of the coated film is tested against electromagnetic waves in the X‐band region (8.2–12.4 GHz) and its shielding behavior (≈24 dB) is confirmed. To demonstrate its wide range of versatility, the coated films are tested against angular strain and oscillatory magnetic fields. The results confirm angle dependent strain sensitivity and induction heating obeying Néel relaxation. To the best of the authors’ knowledge, this is the first synergistic coating archived for mitigating radiation pollution, strain sensing, and non‐contact heating.
The work describes photografting of graphene nanofiber/iron oxide hybrid onto polypropylene film. The hybrid coated film is flexible. The surface morphology contents intermingle nanofiber and spherical iron oxide nanoparticles. The coated film is applied for mitigating electromagnetic pollution, deformation sensing, and non‐contact heating.
On 17 August 2017, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo interferometer detected gravitational waves (GWs) emanating from a binary neutron star merger, ...GW170817. Nearly simultaneously, the Fermi and INTEGRAL (INTErnational Gamma-Ray Astrophysics Laboratory) telescopes detected a gamma-ray transient, GRB 170817A. At 10.9 hours after the GW trigger, we discovered a transient and fading optical source, Swope Supernova Survey 2017a (SSS17a), coincident with GW170817. SSS17a is located in NGC 4993, an S0 galaxy at a distance of 40 megaparsecs. The precise location of GW170817 provides an opportunity to probe the nature of these cataclysmic events by combining electromagnetic and GW observations.
In order to overcome the difficulty of identifying multiple electromagnetic radiation sources (EMRS) of the same frequency and wideband EMRS, a deep neural network model based on blind source ...separation (BSS) and deep feature learning network (DFLN) is proposed. To separate the mixed signal of the unknown source number, a new BSS method based on convolutional neural network (CNN) and shallow neural network (SNN) is proposed. The spatial spectrum, the number of EMRS, and the mixed matrix are estimated by CNN. The separation matrix is estimated by SNN. To effectively identify unknown wideband EMRS, a DFLN based on multiple feature representation learning (MFRL) and similarity metrics (SM) is proposed. The multiple feature representation of EMRS is obtained by two of the same CNNs, and the deep feature representation is learned by SM. The classification layer is improved to identify unknown EMRS. To ensure generalization, both the simulated dataset and the measured dataset are used to train the proposed network. The experiment results show that the average identification accuracy of the proposed method for unknown EMRS reached 98% and about 97% for wideband EMRS.
Developing an ultimate electromagnetic (EM)-absorbing material that can not only dissipate EM energy but also convert the generated heat into electricity is highly desired but remains a significant ...challenge. Here, we report a hybrid Sn@C composite with a biological cell-like splitting ability to address this challenge. The composite consisting of Sn nanoparticles embedded within porous carbon would split under a cycled annealing treatment, leading to more dispersed nanoparticles with an ultrasmall size. Benefiting from an electron-transmitting but a phonon-blocking structure created by the splitting behavior, an EM wave-electricity device constructed by the optimum Sn@C composite could achieve an efficiency of EM to heat at widely used frequency region and a maximum thermoelectric figure of merit of 0.62 at 473 K, as well as a constant output voltage and power under the condition of microwave radiation. This work provides a promising solution for solving EM interference with self-powered EM devices.
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