Search Results (329)

To address trench-bottom electric-field concentration and the limited BV–R_on,sp trade-off of the conventional shielded-gate trench MOSFET (Conventional SGT), a floating-P-island-assisted silicon SGT MOSFET is proposed. Sentaurus TCAD is used to investigate the effects of increasing the number of floating P-islands from 0 to 3 on BV, R_on,sp, FOM, and electric-field distribution. Within this range, the three-floating-P-island device (3FPI-SGT) provides a favorable BV–R_on,sp trade-off; its drift-region doping matching, dynamic characteristics, and parameter sensitivity are further analyzed. Local depletion around multiple vertically discrete P-islands generates secondary electric-field peaks that share the potential drop with the main trench-bottom peak, reducing field crowding and improving voltage utilization of the drift region. After optimization, the maximum BV and FOM reach 177.7 V and 11.48 MW·cm⁻², respectively. At an identical R_on,sp of 2.62 mΩ·cm², BV increases by 54.6%. At V_DS = 80 V, C_oss and C_rss decrease by approximately 12.8% and 12.5%, while total switching energy increases by only approximately 2.5%. A clear BV advantage is retained under ±20% single-factor deviations in key P-island parameters. Thus, the proposed structure significantly improves the silicon SGT MOSFET BV–R_on,sp trade-off with a limited dynamic-performance penalty. Full article

To address the limitations of traditional trench electrode silicon detectors, such as charge collection dead zones and non-uniform electric fields, this paper proposes a novel 3D silicon detector based on an interleaved trench electrode structure. By constructing interleaved N-type and P-type heavily doped trenches on a lightly doped N-type substrate, enhanced uniformity and depth profile optimization of the electric field distribution are achieved. Moreover, 3D numerical simulations based on TCAD demonstrate that the proposed structure provides a uniform, planar-like electric field distribution; reduces low-field regions; and enables fast carrier collection with a low full-depletion voltage. The results provide a theoretical basis and design reference for the development of novel 3D radiation detectors with low depletion voltages, fast charge collection, and favorable radiation response characteristics. Full article

High-bandwidth memory (HBM) faces critical power integrity challenges in high-stack configurations due to elongated power delivery paths and increased parasitic inductance. This paper proposes a dual-interposer HBM architecture with an interposer–HBM stack–interposer configuration, integrating an additional top interposer embedded with chip capacitors. This topology redesigns the HBM’s power distribution network, reducing PDN impedance, and this technology enables bidirectional vertical power supply to DRAM chips during moments when they require current. The PDN impedance is systematically compared with a conventional trench-capacitance-enhanced structure (Structure A) and a deep-trench-capacitance-enhanced structure (Structure B). Results show that at 0.1–11.2 GHz, the proposed structure reduces peak PDN impedance by 66.41% and 65.7% versus Structures A and B, respectively, and decreases the loop inductance of the top-layer DRAM chip by 66.71%. The top interposer’s redistribution layer forms a parallel-plate capacitor complementing the embedded chip capacitors, achieving wideband impedance suppression. Without modifying existing protocols, this architecture provides a system-level PDN optimization strategy for high-stack HBM, offering quantitative insights for capacitor selection and layout design. Full article

To validate the effectiveness of the grooved diaphragm with back peninsulas and trenches (GDPT) and the radial basis function neural network (RBFNN)-based dimension generator in the development of a 1 kPa piezoresistive micropressure sensor, this paper presents a comprehensive investigation into the design, fabrication, and characterization of the anticipative sensor prototype. The GDPT achieves favorable sensing stress and reduced deflection, enabling a favorable trade-off between sensitivity and nonlinearity; the RBFNN-based generator efficiently determines practicable dimensions for the complex structure, offering a significant improvement over the conventional trial-and-error process. Characterization results demonstrate that the fabricated sensor achieves sensitivity of 13.01 mV/(V·kPa) and nonlinearity of 0.26% FS within the pressure range of 0–1 kPa, in good agreement with the preset design target. This work verifies the validity of the proposed approach and offers a holistic methodology for developing high-performance piezoresistive sensors. Full article

Metro train-induced environmental vibrations may adversely affect the performance and comfort of buildings near metro lines, making it necessary to select suitable isolation barrier materials for vibration control. To evaluate the vibration isolation performance of different barrier materials, a vehicle–track coupled dynamic model and a three-dimensional tunnel-soil-structure finite element model were established to predict vibration sources and structural responses. Based on wave propagation characteristics and impedance theory, an impedance-based material selection approach for isolation barriers was proposed. Concrete and foam were selected as representative high- and low-impedance materials, respectively, and were compared with open trenches to evaluate their isolation performance and control mechanisms. Results indicate that building vibrations are mainly concentrated within 20–80 Hz, with dominant peaks around 40–50 Hz. Open trenches provide the most effective low-frequency attenuation, foam-filled trenches achieve stable broadband isolation, and concrete walls are mainly effective at mid-to-high frequencies. Low-impedance filled trenches offer a favorable balance between vibration reduction and engineering feasibility. The findings provide a reference for the design and selection of isolation barriers for buildings adjacent to underground metro tunnels. Full article

Subsurface faults in sediment-covered basins often lack clear surface expressions, necessitating integrated geophysical reconnaissance to identify structural complexities. The eastern margin of the Sofia Basin contains normal faults, with the geometry and activity of unmapped structures near Lozen Mountain being poorly understood. This study examines a presumed subsurface discontinuity using a ~216.2 m passive seismic profile across the Lozen Fault zone. Ambient vibrations from twelve point stations and a fixed reference station were analyzed to map structural anisotropy and wavefield variations using relative vertical-component spectral amplitudes, polarization parameters, and horizontal-to-vertical (H/V) spectral ratios. The spectral amplitude profiling revealed a significant lateral contrast of 6.21 dB across a depth interval of 0–140 m (p = 0.0043), suggesting a potential fault boundary. A two-level step model identified a horizontal transition at 109.0 m, with analyses indicating a zonal wavefield response. Southern stations recorded a more stable polarization axis (mean direction 37.32°) compared to the dispersed northern records (mean direction 60.43°, p = 0.097), while directional shifts in H/V distributions were significant (p = 0.0022). While these observations provide a clear structural indicator rather than direct proof of faulting, they effectively demonstrate that non-tectonic lithological and hydrological variations generate these identical spectral signatures. The results establish a well-constrained spatial target for future multi-profile surveys, electrical resistivity tomography, active-source seismic imaging, and paleoseismological trenches required to conclusively verify the geometry, age, and present-day activity of the fault structure. Full article

This study investigates the repetitive overload turn-off behavior of a 1200 V/15 A trench field-stop IGBT using a clamped inductive load circuit. The DC-link voltage is set to 600, 800, and 1000 V, while the external circuit configuration and the 2 ms pulse interval remain unchanged. The displayed sequences at 600 and 800 V exhibit no destructive failure. Under the 1000 V condition, 24 of 30 devices fail, and the cycle-to-failure ranges from 6 to 27. Before failure, the peak V_CE, turn-off current, and E_off reach 1248.1 V, 80.2 A, and 12.87 mJ, respectively. During the final destructive event, V_CE first recovers to approximately 1.16 kV and then collapses toward zero, while I_C re-grows to approximately 106.8 A. A statically validated two-dimensional simulation model shows pulse-to-pulse temperature accumulation, mobility reduction, expansion of the high-field and impact-ionization regions, and persistence of an electron-rich transport path near the trench-gate active region. Post-failure SEM reveals a filament-like damage trace, emitter-side Al damage, damaged trench-gate structures, and contiguous multi-cell ablation. The combined evidence indicates that repetitive heating progressively strengthens the coupling among carrier transport, electric-field concentration, avalanche generation, current localization, and self-heating, which leads to delayed localized electrothermal instability. An auxiliary RC-IGBT comparison further confirms that the repetitive overload turn-off boundary depends on the device technology and operating conditions. Full article

Capacitive micromachined ultrasonic transducers (CMUTs) have been extensively investigated for applications in medical imaging and industrial non-destructive testing. However, their relatively low acoustic pressure output remains a major limitation to broader adoption. This paper proposes a CMUT structure that combines collapse-mode operation with a trenched membrane to enhance output performance. An analytical model based on von Kármán large-deflection plate theory is developed to estimate the optimal radial position of the trench, thereby defining the search space for subsequent Bayesian optimization. Single-parameter sequential Bayesian optimizations are first performed to identify the individual effects and optimal ranges of the trench’s radial position, depth, and width. Subsequently, a three-parameter global Bayesian optimization framework is employed for global parameter refinement. The three-parameter joint optimization reveals strong synergistic interactions among the design variables, achieving a higher output pressure of 72.34 kPa compared to 70.02 kPa from sequential approaches. Under identical operating conditions, the optimized trenched membrane CMUT exhibits a 100.15% increase in output acoustic pressure and a 28.77% improvement in the pressure-bandwidth product compared to a uniform membrane. Statistical analysis across multiple independent runs yielded a coefficient of variation (CV) of only 0.052% for the output pressure in the three-parameter global optimization results. This confirms that the proposed framework robustly optimizes CMUT designs for high output pressure, offering a promising technical approach to enhancing device performance. Full article

Petit-spot volcanism is a type of intraplate volcanism that commonly occurs near the outer rise in subducting plates. Although deformation of the incoming plate is considered important for its development, the deeper mantle processes contributing to this volcanism remain poorly understood. Here, we use more than 1500 broadband seismograms containing long-period SS precursors to investigate the mantle transition zone (MTZ) beneath the Sunda–Java subduction system. Beneath the northern Sunda–Java region, the 660 km discontinuity (d660) reaches ~690 km depth, resulting in an MTZ thicker than 270 km, consistent with the thermal influence of the subducted Indo-Australian slab. The associated weakening of S660S amplitudes may reflect hydration or other factors affecting the lower MTZ. South of the trench, the MTZ beneath most of the Christmas Island Seamount Province is relatively uniform, with a thickness of ~251 km. Beneath Christmas Island, however, the 410 km discontinuity (d410) is depressed to ~420–425 km, whereas d660 remains near 670–675 km, producing a localized thinner MTZ of ~245–250 km. This structure is compatible with localized slab-related mantle processes and may reflect thermal or compositional heterogeneity near the top of the MTZ. Although our observations do not directly resolve volatile transport or melt generation, they provide new constraints on the deep-mantle environment associated with rejuvenated petit-spot volcanism at Christmas Island. Full article

This study proposes and validates a unified geometry-based capacitance model for four representative silicon detector architectures: planar, 3D trench electrode, 3D spherical electrode, and silicon drift detector (SDD). Closed-form analytical expressions explicitly relate capacitance to key geometric parameters—anode radius, depletion thickness, electrode depth, and electrode spacing—and the resulting geometric scaling laws are rigorously verified by combining physical modeling, TCAD simulation, and experimental measurement. A central finding is that for highly symmetric structures, capacitance is governed almost exclusively by the radius of the collecting anode and is essentially independent of the overall detector volume, thereby defining an ideal low-capacitance limit. For the SDD, a hemispherical capacitor approximation accurately captures this anode-dominated behavior, and measurements on prototypes together with independent literature data confirm that the total capacitance can be decomposed into an intrinsic geometric component and a parasitic contribution. This work provides a unified framework and direct cross-structure design guidelines for minimizing capacitance toward ultra-low-noise, high-performance silicon detectors. Full article

Superconducting nanowire single-photon detectors (SNSPDs) were numerically designed by integrating periodic plasmonic structures onto hBN-protected superconducting BSCCO patterns to enhance absorptance. The numerical investigation of optimized nanocavity array (NCAI) and nanocavity trench array (NCTAI) SNSPDs has revealed that more than one-order-of-magnitude higher absorptance can be achieved at perpendicular incidence, compared to the corresponding meandered BSCCO pattern in a simple resonant optical cavity. The presented SNSPD designs are considerably improved via first and third quarter wavelength nanocavity resonances, as evidenced by the near-field maps and validated by the standard retrieval method. Although the NCAI-SNSPD exhibits a slightly larger absorptance, the NCTAI-SNSPD remains potentially competitive due to its smaller filling factor, which may be beneficial for reduced charge-crowding effect. Full article

In the Neotropical Savanna domain, few equations are available for estimating biomass stocks in Cerrado sensu stricto (CSS), despite the importance of such tools for estimating carbon stocks, understanding ecosystem functioning, and supporting conservation actions. We conducted forest inventories in 40 temporary 1000 m² plots in southeastern Brazil to estimate total and compartmental biomass stocks and to model biomass using structural and edaphic predictors. Total biomass (TB) included aboveground woody biomass (AGWB), necromass, litter, and belowground biomass (BGB). AGWB was estimated for trees with basal diameter ≥ 5 cm using a previously fitted regional equation. Root biomass was sampled using a 1 m³ trench excavated at a single point adjacent to each plot. Necromass was quantified using the line-intersect method along a 50 m transect, considering debris with diameter ≥ 3 cm. Litter was sampled using a 0.25 m² frame placed at the center of each plot. Biomass was modeled on an area basis using a hierarchical approach for TB, total tree biomass (TTB = AGWB + BGB), and AGWB. Mean stocks (Mg ha⁻¹ ± s.d.) were 45.24 ± 17.32 (TB), 20.47 ± 11.26 (AGWB), 18.47 ± 10.88 (BGB), 5.49 ± 4.18 (litter), and 0.81 ± 1.62 (necromass). Models selected using the Akaike Information Criterion (AIC) and validated by repeated k-fold cross-validation achieved rŷy = 0.76, 0.72, and 0.94 and RMSE = 24.40%, 27.06%, and 18.10% for TB, TTB, and AGWB. As the equations were calibrated for CSS under the environmental conditions of the Brazilian semiarid region, their transferability to other Cerrado regions should be considered with caution. The inclusion of soil variables (e.g., Al, Mg, and sand) improved predictions, reducing relative costs and taxonomic dependence, while incorporating nutritional adaptations to the acidic soils characteristic of the biome. Full article

The increasing global demand for marine energy resources, coupled with the deployment of offshore oil and gas pipelines and submarine power cables, highlights the requirement for reliable subsea infrastructure. To protect these assets from environmental hazards and anthropogenic disturbances, seabed burial via trenching is widely adopted, with submarine trenchers serving as the main installation equipment. Trenching involves excavating a trench on the seabed to place pipelines, cables, or other subsea infrastructure. These operations involve complex soil–tool interactions that fundamentally govern cutting resistance, trench-wall stability, and overall equipment performance. Specifically, distinct engineering challenges arise across different trencher configurations: plough trenchers often encounter complex seabed structures, jet-type trenchers are prone to trench sidewall collapse, and mechanical trenchers face cutting difficulties in hard clay. A thorough understanding of these interactions is therefore critical for resolving operational challenges and optimizing trencher efficiency in engineering practice. To deeply understand these type-specific issues, this review summarizes the geomechanical problems associated with various trenching technologies, synthesizes recent research advances from analytical frameworks, physical experiments, and numerical simulations, and identifies existing knowledge gaps. By consolidating these findings, the paper provides a reference for addressing trencher-related engineering challenges, supporting equipment optimization, and facilitating the deployment of offshore energy transmission networks. Full article

In the face of the raw materials crisis and environmental concerns, sustainable waste management has become a priority for current and future generations. Recycling waste from wastewater treatment plants in a closed loop protects natural resources, reduces landfill volumes, and lowers disposal costs. This paper presents the results of tests on the physical, filtration, and mechanical properties of mixtures of washed mineral waste (WMW) from grit chambers with fly ash from the thermal treatment of municipal sewage sludge (SSA) in a fluidized bed furnace. Additionally, radiological tests of the mixture components were conducted. Based on the conducted tests, the possibility of sustainable use in civil engineering, such as soil backfills and embankment construction materials, was assessed. The possibility of safely using waste materials in the indicated construction solutions was demonstrated for mixtures with dominant WMW content (90% and 70% by total weight). The waste mixtures correspond to poorly or medium-grade sands with a small amount of silt (uniformity coefficients of 3.33, 3.50, and 8.00). They are characterized by maximum dry densities of 1.542, 1.770, and 1.780 g/cm³; optimal moisture contents of 12.54, 12.86, and 20.25%; permeability coefficients of 0.08, 0.22, and 0.39 m/d; and internal friction angles of 38.4, 39.5, and 40.1°. The values of the determined parameters of some mixtures are similar to those of natural sands used as construction aggregates. All mixtures meet the geotechnical criteria for use in road embankments, below frost depth, and in flood embankment bodies. Mixtures with a 90% mass fraction of WMW were also approved for application as backfill for installation trenches. However, none of the mixtures met the hydraulic conductivity threshold required for the upper layers of embankments nor for backfill of abutments and retaining structures without the use of an additional binder (cement or lime), which is considered a prerequisite for these applications. Full article

Land degradation and declining groundwater availability threaten the sustainability of rural livelihoods across semi-arid regions. This study evaluates the hydrological performance of contour-based trenches as a low-cost and replicable nature-based solution (Nbs) for soil restoration, runoff regulation, and potential distributed managed aquifer recharge (MAR) in Guerrero, Mexico. The structures were installed on 12% slopes and designed using a simplified water balance criterion based on trench storage capacity, runoff coefficient, and representative rainfall events. Each trench was constructed along contour lines with overflow notches and connecting micro-trenches to improve hydraulic continuity, reduce erosion, and enhance infiltration opportunities under degraded field conditions. After one year of field monitoring, the trenches reached an average filling efficiency of approximately 90% per effective rainfall event, with estimated infiltration rates ranging from 0.0069 to 0.011 L·s⁻¹. Soil moisture in the upper soil layer showed a relative increase of approximately 10–18% compared to adjacent untreated areas, while visible reductions in runoff velocity, sediment transport, and surface erosion were observed across the treated plot. Based on trench storage capacity, observed infiltration behavior, and assumed deep percolation fractions, the potential induced recharge was estimated between 216 and 360 m³·yr⁻¹ (43–72 mm·yr⁻¹). These values represent indicative plot-scale estimates rather than direct measurements of aquifer recharge, since no tracer studies or piezometric validation were performed. The results demonstrate that contour-based trenches contribute not only to infiltration enhancement and runoff control, but also to short-term soil restoration and improved water availability in rainfed agricultural systems. Their low-cost implementation, combined with community-based maintenance and adaptation to local environmental conditions, makes them a viable complementary strategy for strengthening decentralized water management, soil resilience, and climate adaptation in semi-arid rural landscapes. However, long-term effectiveness remains dependent on maintenance continuity, institutional support, and local governance conditions. Further multi-year monitoring and direct hydrogeological validation are recommended to improve the design and replicability of decentralized MAR systems. Full article