Search Results (4,927)

Ultraviolet (UV) radiation was selected in this study to evaluate its assistant remediation effects on Cr-contaminated soil. Various remediation materials, including corn stover (CS), corn stover biochar (CSB), polypyrrole-modified 44 corn stover (PPy-CS), and polypyrrole-modified corn stover biochar (PPy-CSB), were employed to evaluate their synergistic effects with UV radiation. The results showed that UV radiation increased the toxicity characteristic leaching procedure (TCLP) Cr(VI) when no other remediation was added to the contaminated soil. However, when the remediation materials were added, with UV radiation, the contents of TCLP-Cr(VI) decreased, while the contents of Cr(III) increased, and the removal rates of TCLP-Cr(VI) in contaminated soil treated by CSB, PPy-CSB, CS, and PPy-CS were 18.7%, 7.6%, 11.0%, and 8.2% higher than those of the non-irradiated groups, respectively. Notably, the CS group demonstrated superior efficacy in Cr(VI) removal compared with CSB under UV irradiation. Meanwhile, characteristic analysis including electron paramagnetic resonance (EPR), Fourier-transform infrared spectroscopy(FTIR) and X-ray photoelectron spectroscopy(XPS) assisted us in finding reaction mechanisms, which implied that UV irradiation could enhance the content of oxygen free radicals on the material surface and effectively activate the reactions between Cr(VI) and remediation materials. This study verified that UV irradiation could also be a promising tool in the remediation of heavy-metal-contaminated soil. Full article

Currently, acoustic sensing technology is widely applied in military defense, non-destructive testing (NDT), and biomedical imaging, and it is increasingly penetrating various aspects of daily life. However, traditional piezoelectric acoustic sensors are highly susceptible to performance degradation when operated in harsh environments. In contrast, optical microcavities-a class of optical resonant cavities with characteristic dimensions on the micrometer scale—offer distinct advantages, including compact footprints, immunity to electromagnetic interference (EMI), and ultra-high sensitivity. Leveraging these exceptional properties, researchers have extensively explored acoustic sensing technologies based on optical microcavity platforms. This paper reviews recent research progress in optical microcavity-based acoustic sensing, categorized by the structural configurations of the microcavities. First, we introduce the key performance specifications of different optical microcavities in acoustic sensing, such as sensitivity and frequency response bandwidth. Second, we categorically discuss the structural designs of various optical microcavities alongside corresponding optimization methods to improve sensing performance. Finally, we summarize the current applications of optical microcavity-based acoustic sensing across multiple fields and outline future development trends in this research area. Full article

In this research, a high-performance plasmonic refractive index ($RI$) biosensor based on an external metal deposition ($EMD$) technique and photonic crystal fiber ($PCF$) platform for potential cancer detection is presented, investigated, and linked with real-time cancer cells. Variations in the $RI$ of biological fluids are closely associated with pathological conditions, including cancer, due to changes in cellular composition and biomolecular concentration. The proposed tetra-core $PCF–SPR$ biosensor operates within the biologically relevant $RI$ range of $1.33–1.37$, enabling the detection of subtle $RI$ variations corresponding to various cancerous cells. The sensing mechanism of the proposed sensor is based on surface plasmon resonance ($SPR$) and analyzed using coupled mode light theory for both $x\text{-}$ and $y\text{-}$ polarized modes. Key sensing performance parameters, including confinement loss ($CL$), wavelength sensitivity ($WS$), amplitude sensitivity ($AS$), sensor resolution ($SR$), and figure of merit ($FOM$) are systematically evaluated. The biosensor reports a $WS$ of $9769$ and $9069 nm/RIU$ for $x\text{-}pol.$ and $y\text{-}pol.,$ respectively, $AS$ of $623.182$ and $645.087 {RIU}^{-1}$ for $x\text{-}pol.$ and $y\text{-}pol.$ respectively, $SR$ in the order of ${10}^{-5}$ $RIU$, coefficient of determination ($R^2$) of $0.97$ and $0.96$, and $FOM$ of $60.17$ and $53.01 {RIU}^{-1}$ for $x\text{-}pol.$ and $y\text{-}pol.$, respectively. Thus, the proposed $PCF–SPR$ biosensor exhibits a dynamic range of $0.04 RIU$. The sensing results demonstrate high sensitivity and strong resonance characteristics, indicating the capability of the proposed biosensor for label-free and non-invasive detection of cancer-associated $RI$ changes in biological fluids. Thus, the presented biosensor offers a promising approach for the highly sensitive label-free detection of early-stage cancer cells by photonics sensing application. Full article

Driven by the engineering requirement for high acoustic stealth of unmanned underwater vehicles (UUVs), this paper investigates the electromagnetic vibration of an 8-pole, 48-slot, surface-mounted permanent magnet synchronous motor (SPMSM) employed in the propulsion system through multi-physics coupling analysis and experimental testing. First, analytical calculations of electromagnetic force waves are performed based on the Maxwell stress tensor method and the magnetomotive force–permeance method to analyze the spatial orders, temporal orders, and sources of the harmonics. Then, a two-dimensional motor model is established using ANSYS electromagnetic field simulation software to investigate the temporal and spatial characteristics of electromagnetic force waves under both no-load and on-load conditions. Fourier decomposition is applied to obtain the amplitude-frequency characteristics, thereby verifying the correctness of the analytical results. Subsequently, three-dimensional models of the stator core and the complete stator assembly are constructed in the physical field, and their modal frequencies and mode shapes are obtained through simulation. On this basis, harmonic response analysis is conducted by applying electromagnetic force waves to the stator teeth, and vibration simulations are performed in ANSYS Workbench to acquire vibration characteristics. Vibration experiments are then carried out at multiple rotational speeds, and the experimental results are compared with the simulation results to validate the feasibility and accuracy of the finite element modeling approach. Since the measured motor vibration results are influenced not only by electromagnetic excitation forces, but also by various factors such as mechanical structure, instrument installation, and fixture conditions, while the simulation model in this paper inevitably simplifies damping, housing details, inverter control effects, and considers only the effect of radial electromagnetic forces, there exists a certain discrepancy between the simulated and measured motor vibration acceleration results. However, the main vibration trends in the low-frequency range below 800 Hz are basically consistent, particularly at the second and fourth harmonic frequencies, where the vibrations are electromagnetic vibrations caused by radial electromagnetic force waves, with relative errors between the measured and simulated values of 18% and 25%, respectively. This finite element model can be used for preliminary design evaluation of PMSMs and rapid prediction of electromagnetic vibration, providing researchers with a convenient and practical research approach and methodology. Finally, by analyzing factors that may influence motor vibration, this paper proposes design modifications to the stator structure and air-gap width, providing an optimized solution for reducing electromagnetic vibration of the permanent magnet synchronous motor and avoiding resonance. Full article

Diabetes is a major worldwide health concern, which emphasizes the critical need for precise and continuous glucose monitoring devices. This paper introduces a novel, non-invasive method for continuous blood glucose monitoring using on-chip multi-arm sensors designed as earbuds by using UMC 0.18 μm technology. The proposed sensor uses the dielectric characteristics of the earbud to detect variations in glucose levels while operating at various resonant frequencies, including 32, 42, 64, and 94 GHz. The sensitivity of the proposed method was evaluated using a reflection coefficient criterion of $\mid S_{11}\mid \le -6\mathrm{dB}$, confirming its ability to achieve accurate detection when implemented within an earbud device. A 3D electromagnetic high-frequency structure simulator (HFSS) is used to validate the simulation. Only |S₁₁| data are used to determine the glucose concentrations in the blinded prediction group. The results demonstrate a strong correlation between sensor responses and glucose levels. The sensor achieved a sensitivity of 12.4 $\mathrm{M}\mathrm{H}\mathrm{z}/\mathrm{m}\mathrm{g}/\mathrm{d}\mathrm{L}$, 6 $\mathrm{d}\mathrm{B}/\mathrm{m}\mathrm{g}/\mathrm{d}\mathrm{L}$. Moreover, the earbud’s homogeneous tissue architecture and naturally low eccrine sweat gland density lessen susceptibility to confounding physiological variables commonly observed in microwave-based glucose detection. As a major advancement in biomedical sensing technology, this wearable system provides a precise and useful method for non-invasive glucose monitoring. Full article

Background/Objectives: Breast cancer is the most common malignancy among women worldwide. Vacuum-assisted breast biopsy (VABB) has emerged as a minimally invasive alternative to surgical excision, but it may cause post-biopsy scarring that could mimic or obscure malignancies on follow-up imaging. This study aimed to evaluate the imaging characteristics, evolution, and clinical implications of post-VABB scar formation. Methods: We conducted a retrospective study of patients who underwent mammographic or magnetic resonance imaging-guided VABB at our institution between January 2010 and December 2020 and whose follow-up report describes a post-biopsy scar. Patients with malignant or high-risk lesions requiring subsequent surgery or prior breast surgery were excluded. Post-biopsy follow-up mammograms and ultrasounds were reviewed by a fellowship-trained breast radiologist for scar formation, visibility across imaging modalities, and evolution over time. Statistical analysis was performed to assess associations between scar detection and patient or lesion characteristics. Results: Thirty-seven patients (39 lesions) with documented post-biopsy scarring on follow-up imaging reports met the study inclusion criteria. The mean age at biopsy was 51.97 ± 12.40 years. Lesions were almost equally distributed between the right and left breasts, with 19 cases involving the right breast (48.7%) and 20 cases involving the left breast (51.3%). Most cases did not need any workup, except for six cases, where two required further biopsy and four required short-term follow-up. No malignancy was detected during the available follow-up or additional evaluation. Twenty-two scars regressed over time. The estimated mean time to scar regression was 69.47 months. Conclusions: Post-biopsy scarring was documented in a small subset of our institution’s VABB cases over the study period and may resemble malignant findings, particularly on tomosynthesis. Awareness of typical scar characteristics, careful documentation of biopsy sites, and correlation with clip markers are essential to avoid unnecessary interventions. Full article

Parallel converter operation enables flexible capacity expansion of energy-storage power conversion systems. However, parallel converter interactions, filter-inductor saturation, and grid-strength variations increase the risk of resonance instability. The measured current-inductance characteristic is incorporated into an operating-point-dependent closed-loop Norton model. The grid current of an individual converter is decomposed into self-reference, parallel converter coupling, and grid-voltage-disturbance responses. It reveals that converter-side inductance attenuation shifts the internal and parallel resonances to higher frequencies and increases resonance-instability risk, whereas converter number and grid impedance primarily reshape the parallel resonance. A coordinated active-damping method is then developed: PCC voltage feedforward weakens common-network interaction, and capacitor-voltage feedback increases local LCL-filter damping. Simulation and experimental results validate the feasibility and effectiveness of the proposed control method. Experiments with two parallel converters validated the proposed control method. Stable transient current responses were achieved during a simultaneous current-reference step from 50 to 120 A, while the grid-current THD and power-sharing deviation remained below 3% and 5%, respectively. Full article

Background: The rotator cable is thought to contribute to load transmission and preservation of shoulder function in rotator cuff tears; however, its detectability on arthroscopy and magnetic resonance imaging (MRI), agreement between these modalities, and clinical relevance remain incompletely defined. This study evaluated rotator cable visibility on arthroscopy and MRI, factors associated with arthroscopic cable visibility, and its relationship with preoperative active shoulder motion. Methods: This retrospective cross-sectional study included 128 patients who underwent shoulder arthroscopy for supraspinatus tears between January 2019 and February 2023. Arthroscopic video recordings were reviewed for rotator cable visibility. Standardized preoperative MRI review was available in 58 patients. Agreement between MRI and arthroscopic visualization was assessed using Cohen’s kappa and percentage agreement measures. Multivariable binary logistic regression was performed to identify factors independently associated with arthroscopic cable non-visibility. Results: The rotator cable was visible arthroscopically in 79 of 128 patients (61.7%) and on MRI in 38 of 58 patients (65.5%). Overall agreement between MRI and arthroscopy was 67.2% (95% CI, 53.7–79.0%), with a Cohen’s kappa of 0.315 (95% CI, 0.090–0.540; p = 0.011), indicating fair agreement. Positive and negative percent agreement were 78.8% and 52.0%, respectively. Although increasing age was associated with cable non-visibility in univariable analysis, this association did not remain statistically significant after multivariable adjustment. Higher Lafosse grade was independently associated with cable non-visibility in the overall cohort (adjusted OR, 1.43 per grade; 95% CI, 1.04–1.97; p = 0.028), whereas increasing tear size was independently associated with cable non-visibility among patients with full-thickness tears (adjusted OR, 2.78 per category; 95% CI, 1.19–6.52; p = 0.019). The unadjusted association between massive tear size and reduced MRI cable visibility did not remain significant after false discovery rate adjustment (q = 0.276). No statistically significant associations were detected between cable visibility or MRI-measured cable dimensions and preoperative active abduction or forward elevation. Conclusions: MRI and arthroscopy demonstrated fair agreement in the assessment of rotator cable visibility. After multivariable adjustment, cable non-visibility was more closely associated with tear-related characteristics than with patient age. No statistically significant associations were detected between cable characteristics and the assessed preoperative range-of-motion measures; however, smaller or moderate associations cannot be excluded, particularly within the MRI subgroup. Rotator cable visibility should primarily be interpreted as a marker of detectability and tear morphology rather than as a direct surrogate for structural integrity or shoulder function. Full article

Wood and wood-based materials represent low-carbon sustainable alternatives to petroleum sound absorbers, yet their baseline sound absorption coefficient varies drastically with wood species, anatomical cutting orientation and pore connectivity due to strong structural anisotropy. This review systematically integrates multiscale structural regulation, porous acoustic theories and data-driven optimization into a unified framework, revealing that broadband high sound absorption relies on the synergistic coordination of impedance matching, thermo-viscous dissipation and low-frequency resonant mechanisms, rather than simply maximizing porosity. We quantitatively compare state-of-the-art wood absorbers: directionally frozen wood aerogels achieve near-perfect absorption (α = 0.95–1.00, NRC = 0.82) across 520–6300 Hz, marking the current performance benchmark, while multifunctional superhydrophobic wood aerogels deliver moderate absorption (α ≈ 0.40) but stand out as all-biomass weather-resistant composites. Rigid-frame JCA/JCAL and poroelastic Biot models are clarified for wood’s distinct stiffness characteristics, and existing data-driven approaches are categorized, highlighting that most neural surrogates rely solely on FEM simulation without physical impedance-tube validation. Critical unresolved challenges including poor moisture/fire durability, insufficient industrial scalability and incomplete material databases are summarized, and targeted research priorities covering gradient manufacturing, hybrid physics–machine learning models and lifecycle environmental evaluation are proposed. Full article

Permeability prediction and hydraulic rock typing in carbonate reservoirs remain challenging because similar porosity values may correspond to markedly different flow capacities controlled by pore throat size, connectivity, and capillary accessibility. This study aims to develop an integrated workflow for permeability prediction and petrophysical–hydraulic rock typing of a heterogeneous dolomite reservoir using parameters that directly characterize the drainable pore throat network. Routine core analysis, centrifuge-derived capillary pressure curves, nuclear magnetic resonance $T_2$ spectra, electrical measurements, petrographic and SEM observations, and fractal descriptors were jointly analyzed. Capillary pressure curves were fitted with the Li–Horne model and transformed into equivalent pore throat radius distributions; characteristic radii $R_q$, Swanson and Capillary-Parachor parameters, irreducible water saturation, and fractal characteristics were calculated for subsequent regression analysis and rock typing. The conventional $k-\varphi$ relationship showed limited predictive capability, whereas models incorporating $R_{15}-R_{21}$ provided a more reliable permeability estimate. The best-performing relationship was close to $k\propto R^2\varphi$, supporting the interpretation of $R_{20}$ as a centrifuge-derived analog of the effective hydraulic radius. Comparison with FZI, Winland R35, NMR groups, and electrofacies showed that $R_{20}$-based typing produced a compact separation of samples by hydraulic quality. The proposed workflow is presented as a single-well proof of concept and requires validation in independent wells before application to field-scale geological and hydrodynamic models. Full article

When red-bed mudstone is directly used as fill material for building foundations, road subgrades, and similar applications, it is prone to seepage-induced deformation and instability. Amending it with montmorillonite bentonite can effectively regulate its permeability characteristics. Meanwhile, rapid and accurate prediction of the permeability coefficient is crucial for building foundations and road subgrade seepage analysis and stability assessment. This study investigated red-bed mudstone fill material modified with montmorillonite bentonite at different blending ratios. Soil–water characteristic curve tests, saturated/unsaturated permeability tests, and nuclear magnetic resonance (NMR) tests were conducted on the specimens to examine the pore evolution patterns and permeability characteristics of the modified red-bed mudstone, and a predictive model for coefficients was proposed. The results indicate that the incorporation of montmorillonite-based bentonite markedly affects the permeability properties of modified red-bed mudstone fillers. The NMR T₂ spectrum exhibits a bimodal distribution; the incorporation of bentonite and the saturation process result in a marked reduction in large pores and an increase in microporosity. The predictive model achieves higher accuracy when the montmorillonite bentonite content is high. Sensitivity analysis revealed that the maximum pore radius has a far greater influence on permeability than the pore fractal dimension and tortuosity. The research findings provide experimental evidence and theoretical models for the rapid estimation of permeability and seepage stability analysis of modified red-bed mudstone fill materials. Full article

Accurate brain tumor segmentation from multi-modal magnetic resonance imaging (MRI) is essential for clinical diagnosis and treatment planning. However, effectively capturing long-range contextual information and fine lesion boundaries under limited computational budgets remains challenging. In this work, we propose SDFR-Net, a lightweight stage-asymmetric Spectral Diffusion and Frequency–Spatial Refinement Network for efficient 2.5D brain tumor MRI segmentation. Instead of applying identical processing across all hierarchical stages, SDFR-Net adopts stage-dependent spectral diffusion, stage-selective conditional refinement, and asymmetric cross-stage frequency-grid allocation to accommodate the distinct semantic and frequency characteristics of shallow and deep representations. The network consists of a Spectral Diffusion Encoder for spectral-domain contextual propagation, a Frequency–Spatial Enhancement Module for adaptive refinement of multi-scale skip features, and a lightweight Conditional Refinement Decoder for lesion-aware reconstruction. Experiments on the BraTS 2019 and BraTS 2020 datasets demonstrate that SDFR-Net achieves whole-tumor Dice scores of 0.856 and 0.880, respectively, while requiring only 1.33 M parameters. Ablation comparisons of stage-selective FiLM injection and symmetric versus asymmetric frequency-grid schedules further support the stage-asymmetric design. These results indicate that SDFR-Net provides a favorable accuracy–efficiency trade-off for resource-constrained brain tumor MRI segmentation. Full article

We investigate the dynamic magnetic properties of an epitaxial Co₂₅Fe₇₅ thin film grown on a MgAl₂O₄ (001) substrate using broadband ferromagnetic resonance (VNA-FMR). The film exhibits a pronounced fourfold symmetry of the resonance field, characteristic of cubic magnetocrystalline anisotropy. By combining broadband and angular-dependent FMR measurements, we determined a spectroscopic g-factor of 2.083 ± 0.017, an effective magnetization of 1655 ± 31 kA/m, and a cubic magnetocrystalline anisotropy field of 28.25 ± 0.22 mT. Beyond the expected angular dependence of the resonance field, we experimentally demonstrated a pronounced flattening of the frequency versus magnetic field dependence for magnetic field direction located between the principal crystallographic axes. The effect, predicted by conventional ferromagnetic resonance theory but not previously investigated in detail, originates from the equilibrium rotation of the magnetization and is quantitatively described within the Stoner–Wohlfarth framework. For ${\varphi }_H$ = 34°, the resonance frequency remained nearly constant over the magnetic field interval from 6.8 to 26.2 mT at room temperature. A comparison with other (001)-oriented epitaxial magnetic films revealed that similar frequency plateaus can occur over frequencies ranging from 0.9 to 12.35 GHz and over magnetic field intervals from 0.5 to 63 mT. These findings establish a route toward microwave devices that are insensitive to fluctuations in the applied magnetic field and motivate further studies of spin-wave dynamics in this regime. Full article

This paper presents a subwavelength multiband bandstop metamaterial reflector for enhancing antenna gain beyond what is achieved by conventional metallic reflectors. The unit cell was designed to generate multiband stopbands at three frequencies: the first at 1.8 GHz, the second at 2.6 GHz, and the third at 3.5 GHz. The design was implemented on a low-cost FR-4 printed circuit board with a simple design and compact size. The unit-cell structure included a transmission line configuration using the tri-section step-impedance technique, combined with a capacitive load at the end of the transmission line via a double interdigital structure. The structure could control the first, second, and third resonance frequencies to occur at the desired bands and ensured independent resonances. The double interdigital capacitive load significantly increased capacitive loading, generating a strong slow-wave effect along the transmission line structure, exceeding that achieved with conventional capacitive loading techniques. As a result, the transmission line size of the unit cell was drastically reduced from the conventional λ/2 to λ/16. To achieve metamaterial characteristics, the unit cell was modified to exhibit negative permittivity (ENG) for enhanced reflection compared to conventional materials and positive permeability. This was accomplished by adding a rod (ROD) structure behind the main structure using the tri-section step-impedance technique. This configuration generated left-handed current on the structure, resulting in negative permittivity values at all three resonance frequencies. An array of 14 × 14 unit cells was fabricated to form the metamaterial reflector with an overall size of 148 mm × 161.7 mm, which is very compact. The performance was evaluated by placing a single-frequency resonant dipole antenna, operating at the same resonance frequency as the reflector, in front of the reflector along the X-axis plane. The antenna gain increased from approximately 2 dB at all frequencies to about 8 dB. The radiation pattern exhibited directional radiation at 0 degrees. The measured results of frequency responses and antenna gains were close to the simulated results. With superior characteristics and compact size, the proposed metamaterial reflector can be applied for multiband 5G and other modern antenna systems. Full article

Magnetically coupled resonant wireless power transmission (MCR-WPT) is an ideal solution for underwater wireless power transmission (UWPT). However, due to the conductivity of seawater, eddy current loss significantly reduces system transmission efficiency. This study develops an analytical estimation method to derive explicit expressions for eddy current loss and transmission efficiency, characterize their dependence on key parameters, and analyze the resonance frequency characteristics of the MCR-WPT system under different conductivities. The optimal resonant frequency and transmission efficiency improvement under variable-conductivity underwater environments are investigated. First, the coil model is simplified to its equivalent form. Based on the Biot–Savart law, the magnetic field is calculated by integral operations, and an analytical model of the eddy current loss is formulated. Consequently, the expression for the system transmission efficiency in seawater at different depths is derived, and a specific resonance frequency is identified at which the efficiency attains its maximum value. An underwater coil model is established using Ansys Maxwell finite element analysis (FEA), and the effects of electrical conductivity and resonance frequency on eddy current loss and system efficiency are analyzed. Finally, an underwater experimental platform is constructed. A freshwater solution and seawater solutions with varying electrical conductivities are prepared using artificial sea salt and pure water; frequency-sweeping experiments are then conducted. The experimental results are in good agreement with the theoretical analysis and simulations, thereby validating the accuracy of the proposed model. Full article