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With the rapid development of the transient electromagnetic method (TEM), the numerical simulations of three-dimensional anisotropic media have garnered attention. This study used the rational Krylov method to realise the three-dimensional modelling of the ground magnetic-source airborne transient electromagnetic data for arbitrary anisotropic media. First, based on Maxwell's equations, a time-domain electromagnetic equation was derived for anisotropic media. The finite difference method was employed to discretise the equation, and the electromagnetic field was then expressed as the product of an exponential matrix and a vector related to the source. Subsequently, the rational Arnoldi algorithm was adopted to construct the rational Krylov subspace orthogonal basis vectors, and the electromagnetic fields at different times were obtained based on a model reduction strategy. The accuracy of the proposed algorithm was verified through the comparisons of its results with those of other software packages. We calculated the response for different anisotropic parameters of the typical three-dimensional anisotropic models, and analysed the influence of the anisotropic media on the ground magnetic-source airborne transient electromagnetic data. The proposed three-dimensional forward TEM algorithm provides important technical support for identifying the anisotropic geological bodies and lays the foundation for further inversion research. [ABSTRACT FROM AUTHOR]

Continuously to a previous work on qualitatively investigating the probable electromagnetic interacting process among lithosphere, atmosphere and ionosphere, this work aims to quantitatively establish an electromagnetic coupling model among these three spheres prior to the Wenchuan earthquake. Firstly, a underground finite length electrical dipole in a half-space model has been employed to estimate the possible "energy source" for an observable 1.3 mV m-1 electrical field registered at 1440 km Gaobeidian station during the Wenchuan event. The result shows that the seismo-telluric current covers ~105–106 kA if the measuring frequency f = 0.01–10 Hz considered. The central magnitude of the vertical electrical field caused by the current at 0.01 Hz on the Earth's surface can be up to kV m-1. Then, this vertical field acts as an input into an electric field penetration model. It is shown that this field attenuates quickly at the atmosphere and completely vanishes at the top ionosphere and produces a 0.1 mV m-1 additional electrical field at the ionospheric bottom. Through the TIE-GCM, this additional electrical field causes 0.01 % ionospheric variations on electron density and TEC near the Wenchuan epicenter, as well as near its magnetically conjugated point. Further, the simulations have also been discussively performed on frequencies of 1 Hz and 10 Hz. The results demonstrate that the variations of electron density present their maximum values at the height of ~300–400 km and the varied percentages of ionospheric parameters have been beyond 10 %, the same magnitude as what has been registered during the Wenchuan shock. [ABSTRACT FROM AUTHOR]

In diverse realms of research, such as holographic optical tweezer mechanical measurements, colloidal particle motion state examinations, cell tracking, and drug delivery, the localization and analysis of particle motion command paramount significance. Algorithms ranging from conventional numerical methods to advanced deep-learning networks mark substantial strides in the sphere of particle orientation analysis. However, the need for datasets has hindered the application of deep learning in particle tracking. In this work, we elucidated an efficacious methodology pivoted toward generating synthetic datasets conducive to this domain that resonates with robustness and precision when applied to real-world data of tracking 3D particles. We developed a 3D real-time particle positioning network based on the CenterNet network. After conducting experiments, our network has achieved a horizontal positioning error of 0.0478 μm and a z -axis positioning error of 0.1990 μm. It shows the capability to handle real-time tracking of particles, diverse in dimensions, near the focal plane with high precision. In addition, we have rendered all datasets cultivated during this investigation accessible. [ABSTRACT FROM AUTHOR]

In recent years, the proliferation of wearable healthcare devices has marked a revolutionary shift in the personal health monitoring and management paradigm. These devices, ranging from fitness trackers to advanced biosensors, have not only made healthcare more accessible, but have also transformed the way individuals engage with their health data. By continuously monitoring health signs, from physical-based to biochemical-based such as heart rate and blood glucose levels, wearable technology offers insights into human health, enabling a proactive rather than a reactive approach to healthcare. This shift towards personalized health monitoring empowers individuals with the knowledge and tools to make informed decisions about their lifestyle and medical care, potentially leading to the earlier detection of health issues and more tailored treatment plans. This review presents the fabrication methods of flexible wearable healthcare devices and their applications in medical care. The potential challenges and future prospectives are also discussed. [ABSTRACT FROM AUTHOR]

The resistivity method and time-domain-induced polarization (TDIP) are two branches of electric exploration that are used to solve problems in mineral exploration, hydrogeology and engineering geology. In recent years, integrating different physical parameters for joint inversion to improve the accuracy of inversion results has been extensively examined; however, three-dimensional joint inversion of the two methods above has not been realized. To further address this issue, in this research, we used the limited-memory BFGS (L-BFGS) method to develop a three-dimensional joint inversion algorithm of the resistivity method and TDIP based on the cross-gradient constraints. In the new algorithm, the resistivity method and TDIP inversion were iteratively updated alternately to ensure that the inversion results can simultaneously meet the two conditions of obtaining minimum data misfits and finding structural similarity. The three-dimensional synthetic dataset inversion results showed that the models obtained by joint inversion are more accurate in the recovery of both the boundaries and the values of the anomalies. Especially in the background of high noise, joint inversion has higher resolution for the target body. The joint inversion algorithm was also successfully applied to a groundwater detection practice in Beijing, China, in which the practicability of the algorithm was confirmed. [ABSTRACT FROM AUTHOR]

This document discusses recent advances in forward modeling and inversion of geophysical electromagnetic data. The research community studying electromagnetic methods has grown in recent years, with applications expanding to include airborne, marine, and borehole scenarios. However, there are still challenges to accurate modeling and inversion, such as the computational requirements and noise in the data. The document presents eight articles on topics including numerical modeling, inversion, signal processing, and case studies. While 3D inversion is a widely discussed topic, this special issue does not include any articles specifically addressing it, suggesting that it may not yet be practical for real-life situations. [Extracted from the article]