Search Results (1,753)

This paper proposes a Hybrid-Field DD (HFDD) coupler designed for wireless power transfer (WPT) in mobile robots within smart manufacturing environments, utilizing a dual-coupling mechanism of magnetic and electric fields. The proposed coupler integrates Double-D coils for vertical magnetic field concentration with a split metal plate structure for enhanced electric field coupling in a compact, low-profile design. To evaluate the electromagnetic performance and the impact of inevitable eddy current interference, two distinct configurations—Front Plate Arrangement (FPA) and Back Plate Arrangement (BPA)—are analyzed through both theoretical modeling and 3D full-wave simulations (HFSSs). The comparative results demonstrate that the FPA model reduces the peak induced current intensity by 56.23 A/m compared to the BPA and achieves a peak leakage magnetic field intensity of 1.12 A/m, which is 28% lower than the 1.56 A/m observed in the BPA, offering a superior solution for suppressing leakage magnetic field and contributing to robust coupling stability. The high consistency between the proposed analytical methodology and numerical simulations underscores the theoretical robustness of the HFDD structure, establishing a clear design framework for efficient power transfer in robotic applications. Full article

Photovoltaic (PV) plants are typically assessed using ~25-year financial horizons and 25–30-year module performance warranties. However, experience from demanding climates shows that actual lifetimes can be shorter and that dry-condition insulation tests may underestimate risks under wet operation. In such cases, repowering after roughly five years can restore energy yield and reduce operational faults, but it also creates repeated waves of waste and increases manufacturing demand. This study synthesizes evidence on moisture-induced insulation loss, backsheet degradation, and delamination-driven failure escalation and complements it with a transparent 30-year scenario comparing module replacement every 5, 10, and 30 years. The findings suggest that humidity-dependent ground-impedance deterioration, frequent inverter trips, delayed morning start-up, and shutdown risks can emerge within about five years at challenging sites, while dry testing may fail to capture these issues. In a severe scenario, five-year repowering requires six full module sets over 30 years, significantly increasing waste volumes and pressure on manufacturing and recycling systems. Therefore, PV sustainability assessments should reflect the effective repowering interval rather than nominal warranties. Promising solutions include repowering-ready, disassemblable module designs, such as those using soft PDMS gel encapsulation. Full article

This study provides a theoretical assessment of the structural, electronic, and thermal properties of MgMH₃ (M = Mn and Ni) compounds using the full-potential linearized augmented plane wave (FP-LAPW) method, with a range of modern functionals. The thermoelectric properties that are surveyed here relate to the power factor, the dimensionless thermoelectric figure of merit, the thermal conductivity, and the electrical conductivity that are associated with these compounds. The study finds that MgNiH₃ has superior thermoelectric properties compared to MgMnH₃. The analysis of the band structure reveals that both materials conduct electricity like metals, as there is no energy gap (0 eV), indicating that the conduction and valence bands overlap. The thermal conductivity was found to be linearly related to an increase in temperature, whereas the electrical conductivity varied with temperature. At elevated temperatures, the maximum power factor values reach 1.45 × 10⁻³ W/(K².m) for MgMnH₃ and 1.96 × 10⁻³ W/(K².m) for MgNiH₃ at 900 K. Upon examination of the electronic states, the contributions to the metallic nature of these hydrides come largely from the Ni and Mn orbitals. This type of prospective information on the potential of MgNiH₃ and MgMnH₃ in industrial applications, especially thermoelectric applications, is a valuable contribution. Understanding their thermal and electronic structure will demonstrate their potential for industry. Full article

This paper presents two broadband four-way power dividers based on a novel T-coil topology, operating in the 22–32 GHz band (covering the K/Ka bands). Type I adopts a cascaded power division structure, while Type II employs a direct-feed integrated architecture. The innovation lies in the introduction of isolating capacitors at the input and output ports, which significantly shortens the critical transmission line lengths in both topologies. This effectively reduces the equivalent inductance and raises the self-resonant frequency, achieving wideband response while maintaining structural simplicity, compact size, and ease of integration. Both circuits were fabricated using a standard 45 nm CMOS process. The measured core chip areas (excluding pads) are only 0.125 mm² for Type I and 0.066 mm² for Type II, demonstrating excellent integration density. Through even-mode and odd-mode theoretical analysis and full-wave electromagnetic simulation verification, both power dividers exhibit good impedance matching and port isolation across the target frequency band. Measurement results further confirm their performance: across the entire 22–32 GHz band, both power dividers achieve a return loss better than 11 dB and isolation exceeding 15 dB; the insertion loss is 1.1–1.4 dB for Type I and 0.8–1.3 dB for Type II; the amplitude imbalance is below ±0.3 dB and ±0.1 dB, respectively; and the phase imbalance is less than ±5° and ±3°, respectively. All measured data show good agreement with simulation results. In summary, Type I offers advantages in layout flexibility and isolation performance, while Type II excels in insertion loss and chip size. Both provide practical circuit solutions for broadband, high-performance, and compact power division systems. Full article

In this article, a new approach to the applicability of the self-complementarity concept in a classical two-port microstrip patch antenna element is presented. This was accomplished through an illustrative design and an electromagnetic analysis of a broadband two-port rectangular printed radiating element in transmission configuration. A calculated ultra-wide matching bandwidth up to approximately 11 GHz was achieved (BW_{sim-RL≥10 dB} ≈ 11 GHz, f_o = 5.5 GHz, i.e., BW_{sim-relative-matching} ≈ 200%). One of the advantages of this topology is that only two degrees of freedom are needed to acquire a very wide impe-dance bandwidth: the length and the width of the slot. Full-wave analysis shows that sui-table combinations of the patch and slot dimensions allow to obtain the broadband mat-ching behavior. It has broadside radiation toward both hemispheres, which is conserved and considerably stable over a wide frequency range. Its linear polarization, radiation patterns, gain values, and radiation efficiency are adequate from 1 to 8 GHz (BW_{sim-radiation} ≈ 7 GHz, f_{o [sim-rad]} = 4.5 GHz, i.e., 63.6% of its BW_sim-matching, and 156% of its f_{o [sim-rad]}). Moreover, the gain and radiation efficiency exhibit very good flatness across wide frequency ranges. Measurements of S-parameters and radiation patterns validate the calculated results. The proposed antenna element is simple, compact, and light-weight. It has a very wide ope-ration bandwidth (7 GHz), its design is easy and flexible, and it is simple to manufacture. It could be used as a radiating element in different linear polarized antenna arrays. Full article

To meet the increasingly strict requirements of modern communication, radar detection and electronic measurement systems for wide-bandwidth, low-insertion-loss and high-isolation signal routing, this paper presents a 16 × 16 programmable switch matrix that simultaneously achieves wideband operation (DC-40 GHz), low insertion loss (≤0.9 dB maximum), high isolation (>50 dB typical), and systematic modular scalability, a combination not found in existing implementations. The matrix, constructed with high-quality coaxial switches and optimized RF circuitry and electromagnetic structures, provides flexible and stable single-pole multi-throw (SPMT) signal routing across an ultra-wide frequency range from DC to 40 GHz. The switch matrix features a modular architecture, integrating multiple RF switching units, drive control circuits, and communication interface modules. This architecture achieves minimal signal path depth while maintaining full connectivity between any input and output port, directly minimizing cumulative insertion loss. Through precise impedance matching design and isolation structure optimization, the system still exhibits outstanding transmission characteristics at the 40 GHz high-frequency end: typical insertion loss does not exceed 0.9 dB, and the isolation between channels is better than 50 dB, effectively ensuring the integrity of signals in complex multi-channel environments. To meet the requirements of automated testing and remote control, the equipment integrates dual communication interfaces (serial port/network port), supports the SCPI command set and TCP/IP protocol, and can be conveniently embedded in various test platforms to achieve instrument interconnection and test process automation. Experimental verification shows that this matrix exhibits excellent switching stability and signal consistency across the entire 40 GHz, with a switching action time of less than 10 ms. Furthermore, it is capable of real-time topology reconfiguration via a microcontroller or FPGA. These innovations collectively deliver a switch matrix that meets the demanding requirements of 5G communication, millimeter-wave radar, and aerospace defense systems—applications where bandwidth, signal integrity, and system flexibility are paramount. Full article

Objectives: To determine the incidence and outcomes of SARS-CoV-2 infection and to evaluate seroconversion rates and quantify antibody responses to COVID-19 vaccines in two cohorts of persons living with HIV at a possible higher risk of poor outcomes (HCV coinfection and those over the age of 65 years). Methods: We included participants from two established cohorts of persons living with HIV, those who were older than 65 years of age, and those with hepatitis C (HCV) co-infection. Four hundred and seventy-one participants completed questionnaires on SARS-CoV-2 infection and COVID-19 vaccine doses and submitted peripheral blood specimens for measuring antibody levels to COVID-19 antigens, full-length spike trimer, its receptor binding domain (RBD), and nucleocapsid protein (N) at 6-month intervals up to three visits between February 2021 and December 2024. Logistic and ordinal logistic regression models evaluated predictors of seroconversion and antibody levels. Results: Overall, 51% of participants developed a SARS-CoV-2 infection, but it was mild, with only nine requiring hospital admission and no deaths. Overall, 99% of tested specimens had antibodies above threshold to either spike or RBD proteins. Specimens that did not and those with lower antibody levels had testing earlier in the pandemic, and were from participants with fewer vaccine doses, and did not have natural infection. Age, depression, comorbidity, HCV co-infection, current substance use, CD4 count, or HIV viral load were predictive of antibody level. Those with hybrid immunity had higher antibody responses. Conclusions: In cohorts of persons with HIV-HCV coinfection and those who are ageing, we observed high rates of seroconversion to COVID-19 antigens. Antibody levels were higher among those with more vaccine doses, hybrid immunity, and later in the pandemic waves. Although 51% developed a breakthrough infection, outcomes were mild with no deaths. Full article

Background: Dental treatment often requires prolonged mouth opening. This may compromise comfort during spontaneous nasal breathing and saliva swallowing, leading to stress or anxiety. A high-flow nasal cannula (HFNC) delivers warmed and humidified air at high flow rates and may improve breathing comfort; however, the feasibility of its routine use during dental treatment has not been established. Objectives: The primary objective of this pilot study is to evaluate the feasibility of conducting a definitive clinical trial to investigate the use of a HFNC during dental treatment. The secondary objective is to explore preliminary patient-centered outcomes related to stress and comfort to inform the design of future clinical trials. Methods: This single-center, open-label pilot feasibility study will be conducted at Nagasaki University Hospital, with adult patients undergoing routine full-mouth periodontal treatment participating in two treatment sessions, one without a HFNC and one with a HFNC, separated by at least four weeks. The primary feasibility outcomes include recruitment and retention rates, patient tolerance and acceptability of the HFNC, completeness of data collection, and device-related adverse events. The secondary outcomes are exploratory and include physiological stress-related parameters (pulse rate, respiratory rate, autonomic nervous system indices, and electroencephalographic alpha wave activity) and patient-reported comfort assessed using a questionnaire. Conclusions: This pilot study was designed to assess the feasibility and safety of HFNC use during full-mouth periodontal treatment and to inform the design of future definitive clinical trials. In particular, the resultant exploratory patient-centered outcomes and preliminary data may be used to guide outcome selection and sample size estimation. Full article

In response to the need to monitor groundwater migration and structural damage to rock strata during tunnel excavation and coal mining, this paper presents a novel electromagnetic detection system that features continuous ground-based transmission and full-waveform underground observation. As the transmitted waveform is crucial for determining the distribution of induced eddy currents and the characteristics of the secondary field response, studying these response characteristics is essential for the system’s practical application. This study selects four typical transmission waveforms—step, triangular, half-sine and trapezoidal—and uses a tetrahedral, three-dimensional grid discretization method to analyze the transient electromagnetic full-wave response patterns of electrical and magnetic sources under different waveform excitations. This elucidates the propagation characteristics of electromagnetic fields in the medium. The research reveals that the waveform type during energization significantly influences the electromagnetic response, with the full-wave response characteristics of electrical and magnetic sources differing significantly in the near-source region and response trends converging in the far-source region. In practical detection, combining the advantages of the three-component responses of the electrical and magnetic sources can effectively improve detection accuracy. The findings of this study provide important theoretical support for optimizing the design of transient electromagnetic detection systems and precisely interpreting detection data. They also lay a theoretical foundation for electromagnetic detection applications in fields such as mineral resource exploration and engineering geological surveys. Full article

This paper presents the design and experimental validation of a compact low-pass filter based on a quasi-eight-shaped defected ground structure (DGS). The study begins with a single DGS resonator that perturbs the ground-plane current distribution, introducing additional effective inductance and capacitance. An equivalent circuit model is developed to provide physical insight into the resonant mechanism and to establish the relationship between the DGS geometry and the electromagnetic response. By incorporating microstrip stubs on the top layer, the resonant structure is transformed into a low-pass filtering configuration with improved passband characteristics. Subsequently, a higher-order topology composed of two identical quasi-eight DGS units and three microstrip stubs is implemented to significantly enhance the rejection performance and extend the stopband bandwidth. The fabricated prototype exhibits a measured cutoff frequency of approximately 2.1 GHz, with an insertion loss lower than 1 dB in the passband. A wide stopband extending from 2.8 GHz to 8 GHz is achieved, with attenuation exceeding 26 dB. The close agreement between the equivalent circuit model, full-wave electromagnetic simulations, and measured results confirms the effectiveness and physical consistency of the proposed design. Owing to its compact planar implementation and strong harmonic suppression capability, the proposed filter is suitable for microwave front-end and antenna applications. Full article

This paper proposes a millimeter-wave miniature on-chip bandpass filter (BPF) implemented using a 0.18 μm CMOS process. To address the issues of insufficient coupling capability, limited control of transmission zeros, and excessive chip area in traditional on-chip filters, a folded cross-interdigital coupling structure is proposed to enhance coupling efficiency and reduce size. The design incorporates metal–insulator–metal (MIM) capacitors to increase the coupling capacitance between resonators without increasing the area, and utilizes a defected ground structure (DGS) to modify the current distribution at the ground plane, generating additional transmission zeros to improve selectivity. An LC equivalent circuit model was established and verified through full-wave electromagnetic simulation, and the design was validated through chip fabrication and on-wafer measurements. The measurement results show an insertion loss of 3.36 dB and a fractional bandwidth of 49.1% at 32 GHz, with two transmission zeros. The core dimensions are 0.25 mm × 0.18 mm. This design achieves a good balance between miniaturization, selectivity, and insertion loss, making it suitable for millimeter-wave SoC applications. Full article

Photonic jets (PJs) generated from mesoscale dielectric particles can achieve sub-diffraction-scale light field constraints and significant near-field intensity enhancement, which have important application value in the fields of nanoimaging, optical sensing, and laser processing. Recent studies show that the axial-extension and transverse-focus characteristics of PJs can be effectively regulated through interface engineering methods, such as using double-layer structures and truncated geometries. Such structures can be referred to as Janus microstructures separated by surface refracted interfaces. However, systematic research on the effect of incident light polarization on the formation and regulation of PJs on the surface interfaces of Janus systems is lacking. In this study, the PJ characteristics under polarization regulation in curved-interface Janus microcylinders are systematically investigated by performing full-wave numerical simulations. The results show that polarization modulation introduces a new degree of freedom for regulating the energy flow distribution and morphology of PJs. An appropriate polarization state can be selected to effectively regulate key characteristic parameters, such as the length, peak intensity, and full width at half maximum of the nanojet, without changing the particle geometry or material composition. This study reveals the synergy between the surface-interface Janus structures and polarization engineering, providing a new physical method for the flexible regulation of PJs in near-field optics. Full article

To address the existing challenges in mold slag thickness measurement—such as the susceptibility of contact sensors to high-temperature degradation and the limitation of non-contact methods to detecting only the upper slag surface—this study proposes an integrated approach that fuses millimeter-wave radar and eddy current sensors for measuring mold slag thickness in a continuous casting mold. The method innovatively combines two sensing principles: the millimeter-wave radar employs an improved FFT-CZT² high-precision ranging algorithm to perform high-resolution scanning of the solid slag upper surface, reconstructing its topography (error: $\pm$1 mm), while Mel-frequency cepstral coefficients (MFCC) are applied to extract features from the radar intermediate-frequency signals, combined with an enhanced PSO-BP neural network algorithm to predict the thickness of the solid slag layer (error: $\pm$5 mm). Concurrently, an eddy current sensor monitors the liquid slag–molten steel interface position (error: $\pm$1 mm). Through dual-sensor data fusion, the upper surface topography data and solid slag thickness obtained from the radar are spatially registered in three dimensions with the molten steel level information derived from the eddy current sensor. This integration ultimately enables the non-contact synchronous measurement of three key parameters within the mold: solid slag layer thickness, liquid slag layer thickness inversion, and molten steel level. Furthermore, by reconstructing the upper slag surface morphology, the method successfully resolves practical issues such as uneven material distribution, local material deficiency, or excessive feeding. Preliminary experimental verification confirms that the proposed method maintains stable performance even under high-temperature and complex environmental conditions. It thus provides a real-time, accurate, and full-cross-section monitoring solution for mold slag in continuous casting, offering significant practical value for the development of smart steel plants. Full article

Background: Closing extraction spaces with clear aligners remains a significant biomechanical challenge, frequently involving difficulties in sagittal control, torque expression, and intra-arch anchorage. Although various sequential or phased retraction strategies exist, the Caterpillar Motion protocol has not yet been formally defined. This clinical report describes the Caterpillar Motion staging protocol and illustrates its application through representative extraction cases, rather than providing a systematic review or experimental comparison. Case Presentation: Two adult patients with extraction-based malocclusions were treated using the Caterpillar Motion staging protocol. Case 1 involved bimaxillary first-premolar extractions with maximum anchorage requirements and periodontal limitations in the mandibular incisors. Case 2 presented as a full Class II malocclusion requiring maxillary first-premolar extractions with moderate anchorage for sagittal camouflage. In both cases, tooth movement was organized into alternating functional groups, with waves limited to 2 mm of sagittal closure. Discussion: The Caterpillar Motion protocol reduces the risk of aligner bowing effect, increases effective crown engagement, and redistributes anchorage demands by preventing simultaneous shortening of both arch extremities. Both cases demonstrated controlled anterior retraction, stable posterior anchorage, and favorable root parallelism. Conclusions: Caterpillar Motion offers a biomechanically coherent and clinically reproducible staging strategy for clear aligner extraction therapy. Further controlled studies are needed to validate its advantages over traditional linear and en-masse protocols. Full article

Accurate prediction of surface rupture induced by seismogenic fault displacement is essential for the seismic safety assessment of major engineering projects. Most existing numerical simulations adopt quasi-static approaches, in which the effect of fault displacement is simplified as static loading. As a result, these methods cannot represent the dynamic characteristics of the fault rupture process, such as stress-wave propagation, soil inertial effects, and the influence of dynamic loading paths on rupture extension in soil layers. To address this issue, a full-process simulation method is established for simulating rupture of overlying soil subjected to dynamic fault displacement: Firstly, a non-uniform dynamic fault displacement loading is formulated for the two sides of the fault based on viscoelastic artificial boundaries, allowing the differential motion of the bedrock on both sides of the fault to be represented. Secondly, an improved dynamic skeleton curve constitutive model of soil is developed by introducing a minimum modulus constraint, providing an improved description of soil nonlinear dynamic behavior from small-strain hysteresis to large-strain shear failure. The reliability of the proposed method is verified through element-level tests and horizontal-site response simulation. As a benchmark, its ability to reproduce key rupture characteristics under quasi-static conditions is also assessed by comparison with classical quasi-static rupture studies. The method is then applied to simulate rupture extension and deformation response of overlying soil under strike-slip fault displacement. The results show that, compared to quasi-static analysis, dynamic fault displacement produces similar cumulative slip for surface rupture initiation and full connection, but induces transient amplification of peak surface displacement and a wider deformation zone with gentler displacement gradients. These findings demonstrate the necessity of considering dynamic fault dislocation of bedrock–overlying soil interaction in seismic assessments of engineering projects crossing active faults. Full article