Electric-Field Control of Perpendicularly Magnetized Ferrimagnetic Order and Giant Magnetoresistance in Multiferroic Heterostructures.

Electrical control of magnetism is highly desirable for energy-efficient spintronic applications. Realizing electric-field-driven perpendicular magnetization switching has been a long-standing goal, which, however, remains a major challenge. Here, electric-field control of perpendicularly magnetized ferrimagnetic order via strain-mediated magnetoelectric coupling is reported. We show that the gate voltages isothermally toggle the dominant magnetic sublattice of the compensated ferrimagnet FeTb at room temperature, showing high reversibility and good endurance under ambient conditions. By implementing this strategy in FeTb/Pt/Co spin valves with giant magnetoresistance (GMR), we demonstrate that the distinct high and low resistance states can be selectively controlled by the gate voltages with assisting magnetic fields. Our results provide a promising route to use ferrimagnets for developing electric-field-controlled, low-power memory and logic devices.

Topology-Dependent Brownian Gyromotion of a Single Skyrmion.

Noninteracting particles exhibiting Brownian motion have been observed in many occasions of sciences, such as molecules suspended in liquids, optically trapped microbeads, and spin textures in magnetic materials. In particular, a detailed examination of Brownian motion of spin textures is important for designing thermally stable spintronic devices, which motivates the present study. In this Letter, through using temporally and spatially resolved polar magneto-optic Kerr effect microscopy, we have experimentally observed the thermal fluctuation-induced random walk of a single isolated Néel-type magnetic skyrmion in an interfacially asymmetric Ta/CoFeB/TaO_{x} multilayer. An intriguing topology-dependent Brownian gyromotion behavior of skyrmions has been identified. The onset of Brownian gyromotion of a single skyrmion induced by thermal effects, including a nonlinear temperature-dependent diffusion coefficient and topology-dependent gyromotion are further formulated based on the stochastic Thiele equation. The experimental and numerical demonstration of topology-dependent Brownian gyromotion of skyrmions can be useful for understanding the nonequilibrium magnetization dynamics and implementing spintronic devices.

Deep Learning Based Vehicle Detection and Classification Methodology Using Strain Sensors under Bridge Deck.

Vehicle detection and classification have become important tasks for traffic monitoring, transportation management and pavement evaluation. Nowadays there are sensors to detect and classify the vehicles on road. However, on one hand, most sensors rely on direct contact measurement to detect the vehicles, which have to interrupt the traffic. On the other hand, complex road scenes produce much noise to consider when to process the signals. In this paper, a data-driven methodology for the detection and classification of vehicles using strain data is proposed. The sensors are well arranged under the bridge deck without traffic interruption. Next, a cascade pre-processing method is applied for vehicle detection to eliminate in-situ noise. Then, a neural network model is trained to identify the close-range following vehicles and separate them by Non-Maximum Suppression. Finally, a deep convolutional neural network is designed and trained to identify the vehicle types based on the axle group. The methodology was applied in a long-span bridge. Three strain sensors were installed beneath the bridge deck for a week. High robustness and accuracy were obtained by these algorithms. The methodology proposed in this paper is an adaptive and promising method for vehicle detection and classification under complex noise. It would serve as a supplement to current transportation systems and provide reliable data for management and decision-making.

Comparative study on fatigue evaluation of suspenders by introducing actual vehicle trajectory data.

Suspenders play a crucial role in transmitting loads from the bridge deck to the main cable in a suspension bridge. They are susceptible to fatigue due to repeated dynamic loads, particularly traffic loads. Traffic Load Models (TLMs), typically created using Monte-Carlo simulation and Weigh-In-Motion (WIM) data, are employed to evaluate this fatigue. However, these models often overlook practical vehicle trajectories and spatio-temporal distribution, which compromises the precision of fatigue assessments. In this study, we introduce a novel 2D Intelligent Driver Model (2D-IDM) that incorporates actual vehicle trajectories, with a particular focus on transverse vehicle movement. This enhancement aims to improve the fidelity of existing TLMs. To provide a clear, qualitative, and quantitative understanding of the effects of fatigue evaluation with or without actual trajectory characteristics, we have structured this paper as a comparative study. We compare our proposed model, denoted as TLM S-3, with two observation-based models (O-1 and O-2) and two simulation-based models (S-1 and S-2). We conducted an experimental case study on a long-span suspension bridge, where the actual traffic load trajectory was obtained using a WIM-Vision integrated system. To calculate fatigue damage considering both longitudinal and transverse directions, we established a multi-scale Finite Element Model (FEM) using solid element types to simulate the bridge girder. This model can generate the stress influence surface of the bridge and has been verified in both static and dynamic aspects. Our detailed comparative analysis demonstrates the consistency of the proposed 2D-IDM with the actual measured traffic load trajectories. This indicates that our approach can enhance the fidelity and precision of fatigue evaluations for bridge suspenders.

Sonographically Determined Fecal Width: An Objective Indicator of Management of Bladder and Bowel Dysfunction in Children.

OBJECTIVE: To test whether sonographically determined fecal width (SDFW) correlates with symptom improvement in a population of children with bladder and bowel dysfunction (BBD) managed with standard urotherapy (SU), even for those patients lacking initial bowel complaints. METHODS: We retrospectively analyzed 200 pediatric BBD patients managed with SU for at least 3 months. Self-reported symptom improvement (complete, partial, no response) following International Children's Continence Society guidelines was tabulated. Patients with complex urologic diagnoses other than vesicoureteral reflux (VUR) were excluded. Pharmacotherapy choice, physical therapy (PT), urinary tract infection (UTI) occurrence, and VUR status were tabulated. SDFW was recorded. Non-parametric analysis of variants (ANOVA) and parametric/non-parametric t testing were used for analysis. RESULTS: Patients had a mean age of 9.5 years (4-12). Forty-eight patients had no gastrointestinal complaints at presentation. Urotherapy yielded complete, partial, and no responses in 14% (n = 27), 33% (n = 67), and 53% (n = 106) of patients, respectively. The average SDFW for those patients with complete response (2.6 cm) was smaller than the SDFW of those with a partial response (3.1 cm) or no response (3.3 cm) (P = .0001). Non-compliance led to greater SDFW compared to compliant patients (3.7 cm and 3.1 cm, respectively, P = .0001). Fecal width was unaffected by VUR, UTI, PT, or pharmacotherapy. CONCLUSION: SDFW correlates well with symptom improvement in pediatric patients managed for BBD, confirming our hypothesis. SDFW is reasonable as single objective parameter to identify successful management in patients with BBD, extending to those without bowel complaints at presentation.