Search Results (13,924)

The curing of silicone networks from dimethylsilanediol and methylsilanetriol chainbuilder–crosslinker precursor mixtures is investigated from combined quantum/molecular mechanics simulations. Upon screening different crosslinker content from 5 to 15%, we provide a series of atomic-resolution bulk models all featuring 98–99% curing degree, albeit at rather different arrangement of the chains and nodes, respectively. To elucidate the nm scale alignment of the polymer networks, we bridge scales from atomic simulation cells to graph theory and demonstrate the analyses of 3-dimensional percolation of -O-Si-O- bonds, polydimethylsiloxane branching characteristics and the interpenetration of loops. Our findings are discussed in the context of the available experimental data to relate heat of formation, curing degree and elastic properties to the molecular scale structural details—thus promoting the in-depth understanding of silicone resins. Full article

Due to their excellent mechanical stability, chemical stability, and environmentally friendly properties, ceramic materials have received extensive attention for years. Meanwhile, ionic liquids (ILs) have been found to effectively enhance tribological properties when applied as lubricants, which has become a distinctive example of their wide exploration. Here, three novel proton-type ionic liquids containing different polar groups were designed and synthesized as pure lubricants for use on different ceramic friction couples (silicon nitride–silicon nitride, silicon nitride–silicon carbide, and silicon nitride–zirconium oxide contacts), and their lubrication effect was evident. The results indicate that the adsorption behavior and frictional characteristics of different polar groups on a ceramic friction interface differ, largely depending on tribochemical reactions and the formation of a double electric layer on the interface between the ILs and ceramic substrates, without obvious corrosion during sliding. The friction coefficient is reduced by more than 80%, and this excellent anti-friction effect demonstrates that the constructed ionic liquid–ceramic interface tribological system shows good application potential. Based on the analyses of SEM, EDS, and XPS, the tribochemical reaction on the sliding asperity and the film-forming effect were identified as the dominant lubrication mechanisms. Here, the high lubricity and anti-wear performance of ILs containing phosphorus elements on different ceramic contacts is emphasized, enriching the promising application of high-performance ILs for macroscale, high-efficiency lubrication and low wear, which is of significance for engineering and practical applications. Full article

This work presents a low-power photoplethysmography (PPG) readout integrated circuit (IC) that achieves a wide dynamic range (DR) through the direct integration of a voltage-controlled oscillator (VCO)-based quantizer into the photodiode driver. Conventional PPG readout circuits rely on either transimpedance amplifier (TIA) or light-to-digital converter (LDC) topologies, both of which require auxiliary DC suppression loops. These additional loops not only raise power consumption but also limit the achievable DR. The proposed design eliminates the need for such circuits by embedding a linear regulator with a mirroring scale calibrator and a time-domain quantizer. The quantizer provides first-order noise shaping, enabling accurate extraction of the AC PPG signal while the regulator directly handles the large DC current component. Post-layout simulations show that the proposed readout achieves a signal-to-noise-and-distortion ratio (SNDR) of 40.0 dB at 10 µA DC current while consuming only 0.80 µW from a 2.5 V supply. The circuit demonstrates excellent stability across process–voltage–temperature (PVT) corners and maintains high accuracy over a wide DC current range. These features, combined with a compact silicon area of 0.725 mm² using TSMC 250 nm bipolar–CMOS–DMOS (BCD) process, make the proposed IC an attractive candidate for next-generation wearable and biomedical sensing platforms. Full article

The AA2124 aluminium alloy-based metal matrix composites (MMCs) reinforced with the silicon carbide (SiC) were examined under tensile creep at 300 °C. The tests were carried out for the materials of different SiC particle size (3 µm and 0.6 µm) and amount (17 vol.% and 25 vol.%). Creep curves under different constant stresses are presented. A high stress sensitivity of the composites tested was identified for a very narrow range of stress values. As a result, a threshold stress range separating the slow and fast creep stages was easily identified at around 5 Mpa for the composite with a larger SiC particle size and lower content and around 1 Mpa for the two other composites. It means that a very small change in stress applied to the structural element at elevated temperatures may lead to its very rapid collapse or even the destruction of the whole structure. The experimental programme was supplemented by the microstructural observations carried out using the scanning electron microscopy providing data necessary for better understanding the damage mechanisms of the material subjected to creep. An influence of voids on the mechanical response and fracture zones was identified. Attention was paid to the nature of degradation of the composites. Full article

Improving the isotropic magnetic properties of FeSi electrical steels has traditionally focused on enhancing their crystallographic texture and microstructural morphology. Strengthening the cube texture within a ferritic matrix of optimal grain size is known to reduce core losses and increase magnetic induction. However, conventional cold rolling followed by annealing remains insufficient to optimise the magnetic performance of thin FeSi strips fully. This study explores an alternative approach based on grain boundary migration driven by temperature gradients combined with deformation gradients, either across the sheet thickness or between neighbouring grains, in thin, weakly deformed non-oriented (NO) electrical steel sheets. The concept relies on deformation-induced grain growth supported by rapid heat transport to promote the preferential formation of coarse grains with favourable orientations. Experimental material consisted of vacuum-degassed FeSi steel with low silicon content. Controlled deformation was introduced by temper rolling at room temperature with 2–40% thickness reductions, followed by rapid recrystallisation annealing at 950 °C. Microstructure, texture, and residual strain distributions were analysed using inverse pole figure (IPF) maps, kernel average misorientation (KAM) maps, and orientation distribution function (ODF) sections derived from electron backscattered diffraction (EBSD) data. This combined thermomechanical treatment produced coarse-grained microstructures with an enhanced cube texture component, reducing coercivity from 162 A/m to 65 A/m. These results demonstrate that temper rolling combined with dynamic annealing can surpass the limitations of conventional processing routes for NO FeSi steels. Full article

Perovskite solar cells (PSCs) are next-generation solar cells; they are replacing silicon-based solar cells due to their higher efficiency, greater cost-effectiveness, and enhanced potential for various applications. Exceeding the efficiency of crystalline silicon-based solar cells, the commercialization of PSCs has driven not only the development of perovskite photoactive materials but also charge transport layer advancements, interfacial engineering, and processing technologies. PSCs were developed later than dye-sensitized solar cells and organic solar cells; the adoption of techniques previously employed in these technologies is significant to enhancing their performance. Among them, polymers are widely employed in perovskite solar cells to facilitate efficient charge transport, provide interfacial passivation, enhance mechanical flexibility, enable solution-based processing, and improve environmental stability. In this review, we highlight the roles of polymer materials as charge transport layers, interfacial layers, and other functional layers for highly efficient and stable PSCs. Full article

A duplex coating system, consisting of a laser-cladded Fe-Cr-based interlayer and a silicon-doped diamond-like carbon (Si-DLC) top layer, was deposited on medium carbon steel substrate using laser cladding (LC) followed by plasma-enhanced chemical vapor deposition (PECVD). The LC interlayer (thickness of 1.5 mm, hardness of 455–620 HV0.3) was applied on both argon ion-etched and non-etched substrate surfaces. The microstructure and adhesion strength of the coatings were systematically investigated. The results show that the LC interlayer significantly enhanced the mechanical support for the Si-DLC coating, increasing adhesion strength by 4~5 times compared to direct deposition. Argon ion etching introduced micro-roughened surface features, increasing interfacial contact area and further boosting adhesion. A synergistic effect was observed between substrate hardness and ion etching in enhancing Si-DLC coating adhesion. Full article

The energy deposition process for the main components of SIC Schottky diodes is simulated based on Geant4. Particle bombardment results were simulated under different angles, target materials and doping concentrations on the same target material for different light particles and heavy ions, and then the Linear Energy Transfer of SiC materials and external conditions that affect LET are obtained. The results show that the LET value of protons exhibits significant oscillations at low energy incidence, gradually decreasing exponentially after 10⁻¹ MeV. Alpha particles have a LET peak near 1 MeV, while beta particles show an exponential decrease. The LET values at low energy levels increase exponentially, while at high energy levels, the LET values show a similar linear relationship with energy. For different incident angles, the average LET value of protons in the low-level region gradually increases as the incident angle increases. The average LET value of protons in the remaining energy ranges is less affected by angle; the incident angle has no significant effect on the LET distribution of alpha particles within the full spectrum range. The results provide important references for understanding the energy deposition process and LET distribution of silicon carbide devices under single-particle interaction. Full article

Protecting sensitive electronic interfaces is critical in industrial applications, where exposure to harsh conditions and fault events is common. This paper reviews and compares circuit techniques for the design of bidirectional protection switches, highlighting key features such as analog switching, high-voltage capability, thermal shutdown, galvanic input isolation, and adjustable current limiting. Based on this review, we propose a universal architecture that combines the most suitable building blocks identified in the literature, with a focus on options that would enable monolithic integration in high-voltage silicon-on-insulator (SOI) technology and capable of delivering up to 2 A at a maximum voltage of 200 V. The proposed architecture is intended as a design guide for realizing a universal switch, rather than a fabricated implementation. To demonstrate system-level interactions, behavioral MATLAB/Simulink (R2024b) simulations are presented using generic components, which show expected functional responses but are not tied to process-specific device models. Full article

This study presents a high-performance silicon nanowire (SiNW) array biosensor for the combined detection of two key colorectal cancer (CRC) biomarkers: circulating tumor DNA (ctDNA) and carcinoembryonic antigen (CEA). The device was fabricated using conventional micromachining techniques, enabling the integration of dual SiNW arrays on a single chip with precise control over structure and surface functionalization. Specific probe DNA and anti-CEA antibodies were immobilized on distinct array regions to facilitate targeted binding. The biosensor demonstrated exceptional performance, achieving an ultralow detection limit of 10 aM for ctDNA with a linear range from 0.1 fM to 10 pM, and a sensitivity of 1 fg/mL for CEA. It exhibited high selectivity against interfering substances, including single-base mismatched DNA and non-specific proteins, and maintained robust performance in human serum samples. The platform offers a scalable, label-free, and real-time detection solution with significant potential for application in early CRC screening and personalized medicine. Full article

This study investigates the acoustic performance of Ecoflex™ 00-35, a highly flexible silicone rubber, for use in soft and adaptable vibration and noise control systems. Under normal conditions, Ecoflex™ 00-35 consists of two components—Part A and Part B—which are mixed and cured at room temperature to form an elastomer. In this study, curing parameters such as the A/B mixing ratio, thinning agent addition, and curing pressure were varied to examine their effects on acoustic behavior. The microstructure of the prepared samples was analyzed using scanning electron microscopy (SEM), while sound absorption properties were measured using impedance tubes. Test results demonstrated that modifying curing parameters, applying vacuum, and incorporating a thinning agent increased the average cell diameter, leading to the fabrication of a moderate sound absorber with a sound absorption coefficient ranging from 0.35 to 0.60 in the low- to mid-frequency ranges. Further enhancement in low-frequency absorption was achieved by applying low pressure for a short duration, allowing cell expansion. In contrast, the addition of a thinning agent significantly improved absorption at higher frequencies. These findings highlight the influence of processing conditions on the acoustic behavior of soft silicone elastomers and provide valuable insights into their structure–property relationships. Ultimately, this study contributes to the development of advanced materials for acoustic damping and noise control applications. Full article

The electrification of agricultural equipment is a critical pathway to address the dual challenges of increasing global food production and ensuring sustainable agricultural development. As the core power unit, the permanent magnet synchronous motor (PMSM) drive system faces severe challenges in achieving high performance, robustness, and reliable control in complex farmland environments characterized by sudden load changes, extreme operating conditions, and strong interference. This paper provides a comprehensive review of key technological advancements in PMSM drive systems for agricultural electrification. First, it analyzes solutions to enhance the reliability of power converters, including high-frequency silicon carbide (SiC)/gallium nitride (GaN) power device packaging, thermal management, and electromagnetic compatibility (EMC) design. Second, it systematically elaborates on high-performance motor control algorithms such as Direct Torque Control (DTC) and Model Predictive Control (MPC) for improving dynamic response; robust control strategies like Sliding Mode Control (SMC) and Active Disturbance Rejection Control (ADRC) for enhancing resilience; and the latest progress in fault-tolerant control architectures incorporating sensorless technology. Furthermore, the paper identifies core challenges in large-scale applications, including environmental adaptability, real-time multi-machine coordination, and high reliability requirements. Innovatively, this review proposes a closed-loop intelligent control paradigm encompassing environmental disturbance prediction, control parameter self-tuning, and actuator dynamic response. This paradigm provides theoretical support for enhancing the autonomous adaptability and operational quality of agricultural machinery in unstructured environments. Finally, future trends involving deep AI integration, collaborative hardware innovation, and agricultural ecosystem construction are outlined. Full article

Objective: Maxillofacial silicone elastomers represent a standard material in maxillofacial prosthetic applications due to their excellent biocompatibility and aesthetic properties. However, their long-term performance is limited by color degradation and susceptibility to fungal colonization. Incorporating nanoparticles into silicone matrices has emerged as a potential solution to enhance durability and hygiene. This study aimed to evaluate the effect of zinc oxide (ZnO) and titanium dioxide (TiO₂) nanoparticles used individually and in combination to evaluate the color stability and antifungal activity of pigmented maxillofacial silicone elastomers. Material and Methods: Fifty specimens were fabricated for each test and divided into five groups: Group (A) control (pigmented silicone only, no nanoparticles), Group (B) ZnO (1.5 wt%), Group (C) TiO₂ (2.5 wt%), and two combinations: Group(D1) (0.75 wt% ZnO + 1.25 wt% TiO₂) and Group (D2)(0.5 wt% ZnO + 0.83 wt% TiO₂) ratios. Color stability was assessed before and after 500 h of artificial aging using CIELAB-ΔE values and visual scoring. Antifungal activity was evaluated against Candida albicans using the disk diffusion method. Attenuated Total Reflectance with Fourier Transform Infrared Spectroscopy (ATR-FTIR), Scanning electron microscopy (SEM) along side with Energy-dispersive X-ray spectroscopy (EDS) were applied for Specimen characterization. Data were analyzed with one-way ANOVA and Tukey’s post hoc test (α = 0.05). Results: The dual-nanoparticle group with 0.75% ZnO and 1.25% TiO₂ demonstrated the best color stability (ΔE = 0.86 ± 0.50) and strongest antifungal activity (inhibition zone: 7.8 ± 3.8 mm) compared to the control (ΔE = 2.31 ± 0.62; no inhibition). Single-nanoparticle groups showed moderate improvements. A significant Association (r = 0.89, p < 0.01) was found between nanoparticle dispersion and material performance. Conclusions: Incorporating ZnO and TiO₂ nanoparticles into maxillofacial silicone elastomers significantly enhances color stability and antifungal efficacy. The combined formulation showed a synergistic effect, offering promising potential for improving the longevity and hygiene of maxillofacial prostheses. Full article

This work presents the design and simulation of a time-interleaved successive approximation register (SAR) analog-to-digital converter (ADC) implemented in GlobalFoundries’ 22 nm Fully Depleted Silicon-on-Insulator (FD-SOI) CMOS process. Motivated by the increasing demand for high-speed electrical links in data center and AI/ML applications, the proposed ADC architecture targets medium-resolution, high-throughput conversion with optimized power and area efficiency. The design leverages asynchronous SAR operation, bootstrapped sampling switches, and a hybrid binary/non-binary capacitive digital-to-analog converter (DAC) to achieve robust performance across process, voltage, and temperature (PVT) variations. System-level modeling using channel operating margin (COM) methodology guided the specification of key circuit blocks, enabling efficient trade-offs between resolution, speed, and power. Post-layout simulations demonstrated effective number of bits (ENOB) performance consistent with system requirements, while Monte Carlo analysis confirmed the statistical yield. The converter achieved competitive figures of merit compared to state-of-the-art designs, as benchmarked against the Murmann ADC survey. This work highlights critical design considerations for scalable mixed-signal architectures in advanced CMOS nodes and lays the foundation for future integration in high-speed SerDes systems. Full article

This study presents a multiphysics simulation approach to optimize graphite-buffered bilayer anodes for enhanced energy density in lithium-ion batteries, assessing the electrochemical impact of diverse inner-layer materials, including silicon, hard carbon, lithium titanate (LTO), and metallic lithium, in pure and graphite-composite forms. A coupled finite-element model implemented in COMSOL Multiphysics 6.2 was used to integrate spherical lithium diffusion, charge conservation, and the solid electrolyte interphase (SEI) formation kinetics. The evaluated anode structure consisted of a 60 µm-thick bilayer: a 30 µm graphite surface layer coupled with a 30 µm inner layer of alternative active materials. Simulations were performed using an NMC622 cathode, LiPF₆ in EC:EMC electrolyte, at room temperature, under a charge rate of 1 C, considering realistic particle sizes (graphite: 2.5 µm; Si: 0.1 µm; hard carbon: 2.5 µm; LTO: 0.2 µm; Li metal: 0.5 µm), and evaluated over 2000 cycles. The hard carbon/graphite configuration exhibited a capacity fade of 5.8% compared with 7.1% in pure graphite. Additionally, the SEI thickness decreased to 0.20 µm (from 0.25 µm), the overpotential dropped to −17 mV (from −59 mV), and the electrolyte consumption was reduced to 20.8% (from 42.9%). The analysis highlights hard carbon and LTO inner layers as optimal trade-offs between capacity and cycle stability, whereas silicon and lithium metal significantly increased the initial capacity but accelerated SEI formation and impedance growth. These findings demonstrate the graphite-buffered bilayer’s potential to decouple interfacial degradation from high-capacity materials, providing valuable guidelines for the design of advanced lithium-ion battery anodes. Full article