Search Results (651)

The adverse propagation environment in underground coal mine tunnels caused by enclosed spaces, rough surfaces, and dense scatterers severely degrades reliable wireless signal transmission, which further impedes the deployment of IoT applications such as gas monitors and personnel positioning terminals. However, the conventional power enhancement solutions are infeasible for the underground coal mine scenario due to strict explosion-proof safety regulations and battery-powered IoT devices. To address this challenge, we propose singular value decomposition-based Lagrangian optimization (SVD-LOP) to minimize transmit power at the mining base station (MBS) for IRS-assisted coal mine wireless communication systems. In particular, we first establish a three-dimensional twin cluster geometry-based stochastic model (3D-TCGBSM) to accurately characterize the underground coal mine channel. On this basis, we formulate the MBS transmit power minimization problem constrained by user signal-to-noise ratio (SNR) target and IRS phase shifts. To solve this non-convex problem, we propose the SVD-LOP algorithm that performs SVD on the channel matrix to decouple the complex channel coupling and introduces the Lagrange multipliers. Furthermore, we develop a low-complexity successive convex approximation (LC-SCA) algorithm to reduce computational complexity, which constructs a convex approximation of the objective function based on a first-order Taylor expansion and enables suboptimal solutions. Simulation results demonstrate that the proposed SVD-LOP and LC-SCA algorithms achieve transmit power peaks of $20.8\mathrm{dBm}$ and $21.4\mathrm{dBm}$, respectively, which are slightly lower than the $21.8\mathrm{dBm}$ observed for the SDR algorithm. It is evident that these algorithms remain well below the explosion-proof safety threshold, which achieves significant power reduction. However, computational complexity analysis reveals that the proposed SVD-LOP and LC-SCA algorithms achieve $\mathcal{O}\left(N^3\right)$ and $\mathcal{O}\left(N^2\right)$ respectively, which offers substantial reductions compared to the SDR algorithm’s $\mathcal{O}\left(N^7\right)$. Moreover, both proposed algorithms exhibit robust convergence across varying user SNR targets while maintaining stable performance gains under different tunnel roughness scenarios. Full article

The measurement accuracy of six-component force sensors is crucial for reliable hydrodynamic model test results. To enhance data precision, this study presents an efficient calibration device based on a dual-axis rotational mechanism, enabling multi-degree-of-freedom attitude adjustment of the sensor. By applying known forces and moments through various loading conditions and employing the least squares method to obtain a 6 × 6 calibration coefficient matrix, we effectively reduce system errors and external disturbances. The effectiveness of the proposed calibration method is validated using rotational arm tests with a KCS standard ship model. The results indicate that most calibration point errors are below 1%, with the maximum error not exceeding 7%, and the measured data show good agreement with international standards. This method offers high calibration efficiency and accuracy, making it well-suited for the calibration of multi-component force sensors and for use in hydrodynamic, wind tunnel, and other multi-disciplinary experimental applications, promising potential for wider use. Full article

The compactness of the secondary lining in tunnels is crucial for the overall stability and durability of the structures. This study aims to thoroughly analyze the causes and formation mechanisms of voids in the secondary lining, providing scientific guidance for construction and monitoring in tunnel engineering. Firstly, through field investigations and theoretical analysis, key factors leading to the formation of voids in the secondary lining were identified, and a corresponding formation mechanism model was established. The risk of voiding at various positions of the vault was assessed, and risk levels were categorized. Secondly, a novel real-time monitoring system was developed to capture internal void changes within the lining accurately, enabling real-time monitoring of void phenomena. Furthermore, based on a deep understanding of the void formation mechanisms, the monitoring scheme was optimally designed. Field applications verified the effectiveness of the monitoring system and the feasibility of the optimized monitoring scheme. The results indicate that this real-time monitoring system significantly improves the detection accuracy of voids in tunnel linings. The optimized monitoring scheme effectively guides construction, reducing the occurrence of voids and thereby enhancing the quality and safety of tunnel engineering. This study not only provides new technical means for the construction and monitoring of secondary tunnel linings but also offers theoretical references and practical guidance for solving similar engineering problems. Full article

The peregrine falcon, known as the fastest bird in the world, has been studied for its ability to stabilize during high-speed dives, a capability attributed to the configuration of its dorsal feathers. These feathers have inspired the design of vortex generators devices that promote controlled turbulence to delay boundary layer separation on aircraft wings and turbine blades. This study presents an experimental wind tunnel investigation of a bio-inspired peregrine falcon prototype, equipped with movable artificial feathers, a hot-wire anemometer, and a 3D accelerometer. Wake velocity profiles measured behind the prototype revealed fluctuations associated with feather motion. Spectral analysis of the velocity signals, recorded with oscillating feathers at a wind tunnel speed of 10 m/s, showed attenuation of specific frequency components, suggesting that feather dynamics may help mitigate wake fluctuations induced by structural vibrations. Three-dimensional acceleration measurements indicated that prototype vibrations remained below 1 g, with peak differences along the X and Z axes ranging from −0.06 g to 0.06 g, demonstrating the sensitivity of the vibration sensing system. Root Mean Square (RMS) values of velocity signals increased with wind tunnel speed but decreased as the feather inclination angle rose. When the mean value was subtracted from the signal, higher RMS variability was observed, reflecting increased flow disturbance from feather movement. Fast Fourier Transform (FFT) analysis revealed that, for fixed feather angles, spectral magnitudes increased uniformly with wind speed. In contrast, dynamic feather oscillation produced distinctive frequency peaks, highlighting the feather’s influence on the wake structure in the frequency domain. To complement the experimental findings, 3D CFD simulations were conducted on two HAWT-type wind turbines—one with bio-inspired vortex generators and one without. The simulations showed a significant reduction in turbulent kinetic energy contours in the wake of the modified turbine, particularly in the Y-Z plane, compared to the baseline configuration. Full article

Background: Wide-awake local anesthesia with no tourniquet (WALANT) carpal tunnel release (CTR), performed in the clinic setting, has emerged as a safe, efficient, and cost-effective alternative to traditional operating room (OR)-based decompression. With increasing adoption in clinic settings, WALANT CTR offers the potential to improve access, reduce costs, and maintain excellent patient outcomes. Purpose: This clinical practice update provides an evidence-based summary of clinic-based WALANT CTR, including patient selection, procedural setup, safety profile, cost implications, and system-level considerations for implementation. Recent Findings: Multiple prospective and retrospective studies confirm the safety of WALANT CTR in the clinic setting, with complication rates comparable to OR-based procedures and no increase in surgical-site infections when field sterility is used. Cost analyses report a 70–85% reduction in facility costs per operative case, and patient satisfaction remains consistently high, even among those with anxiety disorders or psychiatric conditions. Adjunctive interventions such as virtual reality technology devices and noise-canceling headphones further enhance the awake surgical experience. Institutional adoption remains variable, with barriers including sterility concerns, billing uncertainty, and credentialing logistics. This clinical update offers detailed, practical guidance on implementing WALANT CTR for surgeons and staff, covering scheduling, staff training, clinical integration, billing, and compliance considerations. Summary: Clinic-based WALANT CTR is a high-value, patient-centered approach supported by a growing body of literature. With appropriate patient selection, streamlined workflows, and institutional support, this model can optimize surgical care delivery in both resource-rich and limited environments. Full article

The self-starting capability of straight-bladed H-type Darrieus Vertical Axis Wind Turbines (VAWTs) remains a major constraint for deployment, particularly in urban, low speed, and turbulent environments. We conducted a systematic review of technological strategies to improve self-starting, grouped into five categories: (1) aerodynamic airfoil design, (2) rotor configuration, (3) passive flow control, (4) active flow control, and (5) incident flow augmentation. Searches in Scopus and IEEE Xplore (last search 20 August 2025) covered the period from 2019 to 2026 and included peer-reviewed journal articles in English reporting experimental or numerical interventions on H-type Darrieus VAWTs with at least one start-up metric. From 1212 records, 53 studies met the eligibility after title/abstract screening and full-text assessment. Data were synthesized qualitatively using a comparative thematic approach, highlighting design parameters, operating conditions, and performance metrics (torque and power coefficients) during start-up. Quantitatively, studies reported typical start-up torque gains of 20–30% for airfoil optimization and passive devices, about 25% for incident-flow augmentation, and larger but less certain improvements (around 30%) for active control. Among the strategies, airfoil optimization and passive devices consistently improved start-up torque at low TSR with minimal added systems; rotor-configuration tuning and incident-flow devices further reduced start-up time where structural or siting constraints allowed; and active control showed the largest laboratory gains but with uncertain regarding energy and durability. However, limitations included heterogeneity in designs and metrics, predominance of 2D-Computational Fluid Dynamics (CFDs), and limited 3D/field validation restricted quantitative pooling. Risk of bias was assessed using an ad hoc matrix; overall certainty was rated as low to moderate due to limited validation and inconsistent uncertainty reporting. In conclusions, no single solution is universally optimal; hybrid strategies, combining optimized airfoils with targeted passive or active control, appear most promising. Future work should standardize start-up metrics, adopt validated 3D Fluid–Structure Interaction (FSI) models, and expand wind-tunnel/field trials. Full article

A physical unclonable function (PUF) leverages the unclonable random variations in device behavior due to defects incurred during manufacturing to produce a unique “biometric” that can be used for authentication. Here, we show that the threshold current for the switching of a magnetic tunnel junction via spin transfer torque is sensitive to the nature of structural defects introduced during manufacturing and hence can be the basis of a PUF. We use micromagnetic simulations to study the threshold currents for six different defect morphologies at two different temperatures to establish the viability of a PUF. We also derive the challenge–response set at the two different temperatures to calculate the inter- and intra-Hamming distances for a given challenge. Full article

Microwave irradiation of rocks can reduce the strength of rocks and ease their subsequent excavation. Exploring the combination of microwave and cutting tools for rock breaking under different conditions is important to the practical engineering application of microwaves. Based on a true triaxial microwave-assisted dual-mode mechanical rock-breaking test system, high-power microwave irradiation of rocks was investigated under different true triaxial stresses, durations of microwave irradiation, and cutting tool conditions such as mechanical drilling tools and tunnel boring machine (TBM) hobs. This research provides important data support for improving the rock-breaking efficiency of mine mining and tunneling as well as mechanical cutting tools and TBM hobs. In this experiment, Chifeng basalt with a relatively high strength was adopted as the research object. A 15 kW (2.45-GHz) open high-power microwave device was used to irradiate 200 mm × 200 mm × 200 mm cubic Chifeng basalt samples under conditions of different burial depths, and a cone drill bit was used for staged excavation. After microwave irradiation of Chifeng basalt measuring 400 mm × 400 mm × 400 mm, a 4-inch (102 mm) rotary cutter was employed to conduct round-by-circle cutting and rock-breaking tests in the microwave irradiation area. The results show that under true triaxial stress, the law of rock breaking by microwave irradiation combined with cone drill bits is as follows: the cutting force shows a trend of increasing–decreasing–increasing again–decreasing again. After microwave irradiation combined with hob cutting, the effective range of the influence of the hob is within the third cutting circle, with a range of diameters of approximately 200 mm. The results also indicate that the open microwave device can pre-crack rocks under deep stress, and there is obvious crack propagation. This research has good applicability to microwave-combined cantilever road-headers and TBM as well as in the mining field, and has a promising development prospect. Full article

In this work, we investigate the electrical properties of a metal–insulator–semiconductor (MIS) heterojunction based on porous silicon dioxide (Ag/pSiO₂/Si). The porous silicon (PS) films were elaborated by electrochemical anodization under specific experimental conditions to obtain a porosity of about 55%. Porous silicon (PS) was oxidized by IR-RTP at different oxidation temperatures (Tox) ranging from 200 to 950 °C under an oxygen atmosphere. The morphology of the samples was analyzed using a scanning electron microscope (SEM). Ag/Al and Ag contacts were screen printed on the back and front sides of the heterojunction, respectively. Both the series and shunt resistances were derived from dark current–voltage (I–V) characteristics related to the various Ag/pSiO₂/Si heterojunctions. In this context, the reflectance was also measured at different oxidation temperatures to investigate its correlation with the series resistance (Rs) and shunt resistance (Rsh). The optimum electrical performance was obtained for an oxidation temperature close to 400 °C. Depending on the pSiO₂ thickness, two conduction mechanisms were highlighted within the devices. For a Tox below 200 °C, as well as for the non-oxidized devices, the conduction mechanism is governed by the tunneling current through the pSiO₂ film. However, when the Tox increases and exceeds 200 °C, the pSiO₂ thickness increases, leading to the switching of the conduction mechanism to a thermionic instead of a tunneling effect mechanism. Full article

The precise mapping of rock joint traces is fundamental to the design and safety assessment of foundations, retaining structures, and underground cavities in building and civil engineering. Existing deep learning approaches either impose prohibitive computational demands for on-site deployment or disrupt the topological continuity of subpixel lineaments that govern rock mass behavior. This study presents BATNet-Lite, a lightweight encoder–decoder architecture optimized for joint segmentation on resource-constrained devices. The encoder introduces a Boundary-Aware Token-Mixing (BATM) block that separates feature maps into patch tokens and directionally pooled stripe tokens, and a bidirectional attention mechanism subsequently transfers global context to local descriptors while refining stripe features, thereby capturing long-range connectivity with negligible overhead. A complementary Multi-Scale Line Enhancement (MLE) module combines depth-wise dilated and deformable convolutions to yield scale-invariant responses to joints of varying apertures. In the decoder, a Skeletal-Contrastive Decoder (SCD) employs dual heads to predict segmentation and skeleton maps simultaneously, while an InfoNCE-based contrastive loss enforces their topological consistency without requiring explicit skeleton labels. Training leverages a composite focal Tversky and edge IoU loss under a curriculum-thinning schedule, improving edge adherence and continuity. Ablation experiments confirm that BATM, MLE, and SCD each contribute substantial gains in boundary accuracy and connectivity preservation. By delivering topology-preserving joint maps with small parameters, BATNet-Lite facilitates rapid geological data acquisition for tunnel face mapping, slope inspection, and subsurface digital twin development, thereby supporting safer and more efficient building and underground engineering practice. Full article

In this paper, a novel Tunneling-Drift-Diffusion Field-Effect Transistor (TDDFET) based on the combination of the quantum tunneling and conventional drift-diffusion mechanisms is proposed for the design of ternary logic circuits. The working principle of the TDDFET is analyzed in detail. Then, the device is packaged as a “black box” based on the table lookup method and further embedded into the HSPICE platform using the Verilog-A language. The basic unit circuits, such as the Standard Ternary Inverter (STI), Negative Ternary Inverter (NTI), Positive Ternary Inverter (PTI), Ternary NAND gate (T-NAND), and Ternary NOR gate (T-NOR), are designed. In addition, based on the designed unit circuits, the combinational logic circuits, such as the Ternary Encoder (T-Encoder), Ternary Decoder (T-Decoder), and Ternary Half Adder (T-HA), and the sequential logic circuits, such as the Ternary D-Latch and edge-triggered Ternary D Flip-Flop (T-DFF), are built, which has important significance for the subsequent investigation of ternary logic circuits. Full article

We present a highly sensitive and selective gas sensor based on an advanced silicon-on-insulator tunnel field-effect transistor (SOI-TFET) architecture, enhanced through the integration of customized conducting polymers. In this design, traditional metal gates are replaced with distinct functional polymers—PPP-TOS/AcCN, PP-TOS/AcCN, PP-FE(CN)₆³⁻/H₂O, PPP-TCNQ-TOS/AcCN, and PPP-ClO₄/AcCN—which enable precise molecular recognition and discrimination of various target gases. To further enhance sensitivity, the device employs an oppositely doped source region, significantly improving gate control and promoting stronger band-to-band tunneling. This structural modification amplifies sensing signals and improves noise immunity, allowing reliable detection at trace concentrations. Additionally, optimization of the subthreshold swing contributes to faster switching and response times. Thermal stability is addressed by embedding a P-type buffer layer within the buried oxide, which increases thermal conductivity and reduces lattice temperature, further stabilizing device performance. Experimental results demonstrate that the proposed sensor outperforms conventional SOI-TFET designs, exhibiting superior sensitivity and selectivity toward analytes such as methanol, chloroform, isopropanol, and hexane. Beyond gas sensing, the unique polymer-functionalized gate design enables integration of microbial biosensing capabilities, making the platform highly versatile for biochemical detection. This work offers a promising pathway toward ultra-sensitive, low-power sensing technologies for environmental monitoring, industrial safety, and medical diagnostics. Full article

Hexagonal Boron Nitride (h-BN) is an exceptional dielectric material with significant potential for high-performance electronic and optoelectronic devices. While previous studies have explored its role in GaN-based MIS (metal/insulator/semiconductor) structures, the influence of few-layer h-BN on AlGaN MIS devices—particularly with varying Al compositions—remains unexplored. In this work, we systematically investigate the Fowler–Nordheim tunneling effect in few-layer h-BN integrated into AlGaN MIS architectures, focusing on the critical roles h-BN layer count, AlGaN alloy composition, and interfacial properties in determining device performance. Through combined simulations and experiments, we accurately determine key physical parameters, such as the layer-dependent effective mass and band alignment, and analyze their role in optimizing MIS device characteristics. Our findings reveal that the 2D h-BN insulating layer not only enhances breakdown voltage and reduces leakage current but also mitigates interfacial defects and Shockley–Read–Hall recombination, enabling high-performance AlGaN MIS devices under elevated voltage and power conditions. This study provides fundamental insights into h-BN-based AlGaN MIS structures and advances their applications in next-generation high-power and high-frequency electronics. Full article

The unique properties of graphene have allowed for the development of graphene-based field-effect transistors (GFETs) for applications in biosensors and chemical devices. However, the modeling and optimization of GFET performance exhibit great challenges. Herein, we propose a quantum transport simulation model for graphene-based field-effect transistors (GFETs) implemented in the open-source Octave programming language. The proposed simulation model (named SimQ) combines the Landauer–Büttiker formalism with self-consistent Schrödinger–Poisson solutions, enabling reliable simulations of transport phenomena. Our approach agrees well with established models, achieving Landauer–Büttiker transmission and tunneling transmission of 0.28 and 0.92, respectively, which are validated against experimental data. The model can predict key GFET characteristics, including carrier mobilities (500–4000 cm²/V·s), quantum capacitance effects, and high-frequency operation (80–100 GHz). SimQ offers detailed insights into charge distribution and wave function evolution, achieving an enhanced computational efficiency through optimized algorithms. Our work contributes to the modeling of graphene-based field-effect transistors, providing a flexible and accessible simulation platform for designing and optimizing GFETs with potential applications in the next generation of electronic devices. Full article

Measuring weak magnetic fields proposes significant challenges to the sensing capabilities of magnetic field sensors. The magnetic field detection capacity of tunnel magnetoresistance (TMR) sensors is often insufficient for such applications, necessitating targeted optimization strategies to improve their performance in weak-field measurements. Utilizing magnetic flux concentrators (MFCs) offers an effective approach to enhance TMR sensitivity. In this study, the finite element method was employed to analyze the effects of different MFC geometric structures on the uniformity of the magnetic field in the air gap and the magnetic circuit gain (MCG). It was determined that the MCG of the MFC is not directly related to the absolute values of its parameters but rather to their ratios. Simulation analyses evaluated the impact of these parameter ratios on both the MCG and its spatial distribution uniformity, leading to the formulation of MFC design optimization principles. Building on these simulation-derived principles, several MFCs were fabricated using the 1J85 material, and an experimental platform was established to validate the simulation findings. The fabricated MFCs achieved an MCG of 7.325 times. Based on the previously developed TMR devices, a detection sensitivity of 2.46 nT/$\sqrt{\mathrm{Hz}}$ @1Hz was obtained. By optimizing parameter configurations, this work provides theoretical guidance for further enhancing the performance of TMR sensors in magnetic field measurements. Full article