Search Results (333)

A high-sensitivity and high-stability on-chip temperature sensor based on a silicon-on-insulator (SOI) platform is proposed and experimentally demonstrated in this work. The device employs a ring-assisted asymmetric Mach–Zehnder interferometer (RAMZI), enhancing both temperature sensitivity and measurement stability. Broadband, wavelength-insensitive components, including multimode interference couplers and adiabatic 3 dB splitters, reduce the influence of laser wavelength fluctuations and mitigate interference errors caused by environmental perturbations. The sensor achieves a temperature sensitivity of 108.74 pm/K, corresponding to an approximately 40% improvement over a conventional AMZI with the same footprint. Moreover, a wavelength drift of only 18 pm over 45 min demonstrates excellent stability and robustness. This work provides an effective solution for highly sensitive and stable on-chip temperature sensing in photonic integrated systems. Full article

This paper presents a high-temperature silicon resonant pressure microsensor capable of stable operation up to 175 °C and 175 MPa, addressing the critical need for reliable pressure monitoring in deep well drilling and petroleum exploration. To overcome the inherent trade-off between pressure range and sensitivity in diaphragm-based sensors, the sensor incorporates V-shaped micro-beam supports that convert radial compressive stress into supplementary axial tensile stress on the resonant beams. This innovative force-transmission structure enhances both pressure resistance and positive stress sensitivity, enabling range extension while maintaining adequate sensitivity. A key feature of this work is the implementation of a frequency-ratio measurement scheme utilizing a dedicated pressure-insensitive reference resonator. This approach effectively eliminates the dependence on the stability of the external crystal oscillator frequency, a significant source of error in high-temperature environments where stable clock sources are costly or unavailable. Experimental results demonstrate that the fabricated sensor achieves a pressure sensitivity of 723.56 ppm/MPa for Resonator I and −436.60 ppm/MPa for Resonator II. The frequency-ratio output scheme maintains a measurement accuracy better than 0.02% FS (within the 0–36 MPa verification range) even when using a low-stability oscillator at 125 °C, significantly outperforming conventional direct-frequency measurement methods. The sensor’s combination of an extended pressure range, high-temperature capability, and robust frequency-ratio output offers a promising solution for high-precision pressure sensing in extreme downhole conditions. Full article

The design of broadband, high-efficiency solar absorbers remains challenging due to the complex and ill-posed inverse mapping from the target optical responses to the physical structures in inverse design optimization. To address this, we propose a joint forward–inverse deep learning framework that enables the rapid and accurate optimization of multilayer metamaterial absorbers. This method integrates an inverse network based on a Modified Swin Transformer with a Multilayer Perceptron forward proxy and performs end-to-end training in a consistency-driven cycle. This strategy reduces the one-to-many ambiguity in inverse design and improves the prediction accuracy, with normalized test mean squared errors of 7.2 × 10⁻⁵ (inverse) and 6.8 × 10⁻⁵ (forward). Using this framework, we optimized an absorber comprising W/SiO₂ hyperbolic metamaterial stacks and TiO₂/SiO₂ anti-reflection coatings, achieving 97.4% average absorptivity across the 400–1750 nm solar spectrum, along with polarization insensitivity and robust wide-angle performance up to 60° incidence. The outdoor solar heating tests showed that the fabricated absorber reaches a peak temperature of 86.3 °C under natural sunlight, with an irradiance peak of about 850 W/m² at noon. This work shows that combining forward and reverse deep learning provides a powerful and scalable paradigm for accelerating the intelligent design of high-performance solar thermal metamaterials. Full article

Limited by the material response characteristics and structural design, the development of dynamically tunable terahertz absorbers with multi-functional properties remains a major challenge. In this study, a dual-tunable terahertz absorber based on the synergistic integration of strontium titanate (STO) and Dirac semimetal (BDS) is proposed. By utilizing the temperature-sensitive dielectric constant of STO and the electrically tunable conductivity of BDS, the device can realize on-demand switching between a broadband absorption mode (absorptivity >90% in the 1.347~2.1271 THz band) and a dual-narrowband absorption mode under external field excitation. Notably, the centrosymmetric cross-patterned structure on the top layer ensures the polarization insensitivity of the device, and this single structure can also serve as a high-sensitivity temperature sensor. Simulation results verify that the device exhibits stable performance under different incident angles and environmental variations. This study constructs a compact multi-functional device platform integrating dynamic absorption regulation and in situ sensing, which provides a new technical route for the development of intelligent terahertz systems in the fields of terahertz imaging, communication, detection and other related areas. Full article

Extrusion processing can induce gel-like network formation in plant proteins, enabling the advancement of structured meat alternatives with tailored textural properties. In this study, extrusion-induced gelation behavior of isolated mung bean protein (IMBP) was systematically investigated during the manufacture of low-moisture meat analogs (LMMA). The effects of key processing variables, rotational speed of the screw, moisture level, and processing temperature on gel network development, hydration behavior, and textural responses were evaluated using response surface methodology as an analytical framework. Increasing moisture content promoted protein hydration and facilitated the formation of continuous gel-like interactions, resulting in enhanced pore development and water-holding capacity. Variations in screw speed and processing temperature further modulated the extent of protein denaturation and network consolidation, influencing nitrogen solubility and mechanical properties. While the integrity index remained relatively insensitive to processing conditions, structural and functional responses exhibited clear dependencies on extrusion-induced gelation dynamics. The extrusion conditions of 39% moisture, 216 rpm, and 159 °C promoted the development of a well-defined protein network, leading to improved functional properties. These findings provide mechanistic insight into extrusion-driven gelation of IMBP and highlight its potential as a protein matrix for gel-based meat analog applications. Full article

Background: Congenital Insensitivity to Pain and Anhidrosis (CIPA) is a rare autosomal recessive disorder characterized by congenital analgesia, anhidrosis, and multisystem involvement affecting the musculoskeletal, cutaneous, oral, and para-oral structures. This case report describes the oral phenotype and multidisciplinary clinical management of a child with CIPA. Case Description: A 9-year-old boy presented with poor oral hygiene, multiple severely damaged teeth, masticatory difficulty, limited mouth opening, impaired bolus control, and para-oral traumatic injuries. Medical and orthopedic history indicated recurrent painless fractures, self-inflicted injuries, cutaneous scarring, and recurrent hyperpyrexia. Oral self-injury associated with CIPA was suspected and supported by the Nociception Assessment Test and Minor’s Iodine–Starch Test. Although the clinical findings were suggestive of CIPA, the diagnosis remained presumptive due to the absence of confirmatory molecular or histopathological testing. Management: A wearable wireless continuous temperature-monitoring device was prescribed to assist in tracking hyperpyrexia associated with CIPA (RHA-CIPA). A conservative, staged, multidisciplinary treatment was planned rather than full-mouth extraction, emphasizing prevention of dental sepsis and mitigation of future self-injury. Dental procedures were performed under local anesthesia to manage discomfort related to tactile hyperesthesia. To reduce nocturnal biting and oral trauma, a hard acrylic occlusal protector was fabricated using an intraoral scanner and a 3D-printed cast. The patient was followed for 12 months. Outcomes: At the 12-month follow-up, clinical improvement was observed, with particularly notable gains in cheek elasticity and soft tissue resilience. Conclusions: This case highlights the considerable challenges involved in the interdisciplinary management of children with CIPA, including oral self-injury prevention, limited mouth opening, and the necessity of close coordination with medical specialties. These findings are descriptive observations of a single case and do not establish efficacy or generalizability of any intervention. Full article

Flexible, intelligent color-changing windows with excellent color-switching capability and fast response time rely significantly on conductive composite layers composed of electrochromic materials and flexible, transparent substrates. Herein, we developed a high-performance electrochromic film (CPC) with mechanical, humidity, and temperature insensitivity by coating sodium carboxymethyl cellulose (CMC)-dispersed PEDOT:PSS onto a CA film. In the CPC system, CMC not only effectively enhances interfacial bonding and compatibility between the hydrophobic CA film and the hydrophilic PEDOT:PSS but also enables uniform and stable deposition of PEDOT:PSS on the CA film. As a result, the designed CPC demonstrates a high optical modulation capability (the transmittance changes from 60.1% to 3%) and a response time of 2 s. In addition, the CPC features the advantages of mechanical-, humidity-, and temperature-insensitive electrochromic distinctions, where it outputs the stable coloring efficiency with 100-time bending treatment, various temperatures, and humidity in an all-day outdoor environment. The developed CPC electrochromic film offers new insights into promoting the structural simplification and sustainability of electrochromic materials. Full article

A novel lytic bacteriophage, XAN_XB1, was isolated from hospital wastewater through host bacterial enrichment and evaluated for its potential in controlling multidrug-resistant Stenotrophomonas maltophilia infections. Transmission electron microscopy revealed that XAN_XB1 has a long tail, possessing an icosahedral head of ~80 nm in diameter and a tail measuring ~150 nm in length. It produced clear plaques of 0.5–1 mm on host bacterial lawns. Host range analysis demonstrated its ability to infect multiple multidrug-resistant S. maltophilia isolates. Biological characterization showed that the phage is chloroform-insensitive, retains strong lytic activity across a wide temperature (4–60 °C) and pH (3.0–10.0) range, and achieves more rapid host suppression under higher multiplicity of infection (MOI). Whole-genome sequencing determined a ~47 kb double-stranded DNA genome encoding 71 predicted open reading frames, with no known virulence or antibiotic resistance genes. Phylogenetic analysis of MCP and terminase large subunit sequences placed XAN_XB1 in a unique Caudoviricetes, with ANI values below the 95% ICTV threshold verifying its status as a novel phage species. The XAN_XB1 therapy significantly alleviates S. maltophilia infection-induced severe pulmonary inflammatory lesions, high mortality, elevated serum inflammatory factors and massive pulmonary bacterial colonization in male BALB/c mice, confirming its favorable therapeutic effect on such infections. Collectively, these results reveal that is an efficacious candidate for therapeutic development against S. maltophilia infections. Full article

In the present study, molecular dynamics simulations with three interatomic potentials (Polymer Consistent Force Field, Adaptive Intermolecular Reactive Empirical Bond Order, and Tersoff) are employed to investigate strain-dependent interfacial thermal resistance across one-dimensional to two-dimensional junctions. Carbon nanotube–graphene junctions exhibit exceptionally low interfacial resistances (1.69–2.37 × 10⁻¹⁰ K·m²/W at 300 K)—two to three orders of magnitude lower than conventional metal–dielectric interfaces. Strain-dependent behavior is highly potential-dependent, with different potentials showing inverse, positive, or minimal strain sensitivity. Local phonon density of states analysis with Tersoff reveals that strain-induced spectral redistribution in graphene toward lower frequencies enhances phonon coupling with carbon nanotube modes. Temperature significantly affects resistance, with 37–59% increases at 10 K compared to 300 K due to long-wavelength phonon scattering. Boron nitride nanotube–hexagonal boron nitride nanosheet junctions exhibit 60% higher resistance (3.2 × 10⁻¹⁰ K·m²/W) with temperature-dependent strain behavior and spacing-insensitive performance. Interfacial resistance is independent of pillar height, confirming junction-dominated transport. The discovery of exceptionally low interfacial resistances and material-specific strain responses enables the engineering of thermally switchable devices and mechanically robust thermal pathways. These findings directly address critical challenges in next-generation flexible electronics where devices must simultaneously manage high heat fluxes while maintaining thermal performance under repeated mechanical deformation. Full article

The transient dynamics of electromagnetically induced transparency (EIT) are fundamental to understanding coherent light–atom interactions and the advancement of quantum technologies such as optical switching and quantum memory. However, in room-temperature atomic vapors, Doppler broadening significantly alters these dynamics, yet a comprehensive understanding of its impact on the transient EIT response remains lacking. In this study, we combine analytical and numerical methods to investigate the absorption dynamics of a weak probe field in a three-level Λ-type system driven by a strong coupling field, based on the optical Bloch equations and Laplace transform techniques. Our results show that the transient response is highly sensitive to both the atomic spontaneous emission rate and the Rabi frequency of the coupling field. Increasing the coupling field intensity not only accelerates the approach to steady state but also induces oscillatory dynamics and negative absorption. Under Doppler broadening, the time required to reach steady state increases by approximately three orders of magnitude compared to the Doppler-free case—an effect that is surprisingly insensitive to temperature variations across the 100–400 K range. Moreover, restoring a short steady-state time under broadened conditions necessitates increasing the coupling laser intensity by two orders of magnitude. These findings provide key insights into the influence of Doppler broadening on coherent transient processes and offer practical guidelines for the design of room-temperature atomic devices, including quantum memories and optical modulators. Full article

The increasing market demand for high-power and high-frequency applications necessitates the development of highly reliable Gallium Nitride (GaN) High-Electron-Mobility Transistors (HEMTs). While GaN offers superior performance and efficiency over traditional silicon, gate-related defects pose a significant reliability challenge, often leading to premature device failure under stress. Traditional High-Temperature Gate Bias (HTGB) testing is effective but time-consuming and costly, particularly when defects are only identified post-packaging. This study focuses on developing an effective wafer-level screening methodology to mitigate the financial burden and reputational risk associated with late-stage defect discovery. Failure analysis of an HTGB premature failure revealed a gate metal deposition defect characterized by identical elemental composition to the bulk metal, suggesting a small-volume structural anomaly. Crucially, a comparative analysis showed that Forward Gate Current (I_GON) is an insensitive screening metric due to high inherent gate leakage through the passivation layer. In contrast, the Reverse Gate Current (I_GOFF) exhibited sensitivity, particularly under the tensile stress induced by package molding, which is attributed to the piezoelectric effect altering the depletion region width beneath the p-GaN gate. Based on this observation, a multi-pulse I_DSS test was developed as a wafer-level screen. This method successfully amplified the subtle electrical field perturbations caused by the gate defect. After screening 231 dies using the new methodology, zero failures were recorded after 1000 h of HTGB stress, a significant improvement over the initial failure rate of 0.43% (1 out of 231). This work demonstrates that early, sensitive wafer-level screening of gate defects is indispensable for optimizing manufacturing yield and enhancing long-term device reliability. Full article

In recent years CO₂ reforming of methane has attracted great interest as it produces high CO/H₂ ratio syngas suitable for the synthesis of higher hydrocarbons and oxygenated derivatives since it is a way for disposing and recycling two greenhouse gases with high environmental impact, CH₄ and CO₂, and because it is regarded as a potential route to store and transmit energy due to its strong endothermic effect. Along with noble metals, all the group VIII metals except for osmium have been studied for catalytic CO₂ reforming of methane. It was found that the catalytic activity of Ni, though lower than those of Ru and Rh, was higher than the catalytic activities of Pt and Pd. Although noble metals have been proven to be insensitive to coke, the high cost and restricted availability limit their use in this process. It is therefore valuable to develop stable Ni-based catalysts. In this contribution, we show how their activity and coking resistivity are greatly related to the size and dispersion of Ni particles. Well-dispersed Ni nanoparticles were achieved by multistep impregnation on a mesoporous silica support, namely SBA-15, obtained through a sol-gel method, using acetate as a nickel precursor and keeping the Ni loading between 5% and 11%. Significant catalytic activity was obtained at temperatures as low as 450 °C, a temperature well below their deactivation temperature, i.e., 700 °C. For the pre-reduced samples, a CO₂ conversion higher than 99% was obtained at approximately 680 °C. As such, their deactivation by sintering and coke formation was prevented. To the best of our knowledge, no Ni-based catalysts with complete CO₂ conversion at temperatures lower than 800 °C have been reported so far. Full article

Thermoplastic composites are growing in popularity in the aerospace and automotive industries; they enable weldable and recyclable structures. Resistance welded hybrid thermoplastic and metal joints are attractive for rapid assembly, but the thermal mismatch between metals and polymers introduces residual stresses, which can drive edge debonding and compromise durability. This study presents fabricated single-lap PC/CF–Al7075 coupons with measured mid-span bow resulting from welding, evaluated bond quality by step-heating thermography, and an evaluated framework for residual stress prediction using Ansys complemented by a bimetal analytical check. Three thermal cycles were examined with different temperature gradients (200, 220, 240 °C): the measured bow was 16.5 mm and remained constant, whereas analytical calculation increased with ΔT similarly to the FEM prediction. The current FEM under predicted the bow (Mean Absolute Percentage Error is 21%), showing stress contours that decay with distance from the bond and revealing pronounced peaks in both σ_xx and σ_zz components at weld edges, consistent with shear-lag theory. FEM returned edge-peaked peel rising from 43 to −64 MPa and σ_xx was up to 12% more compressive than analytical calculation; an effective CF/PC CTE of 1.5 × 10⁻⁶ K⁻¹ reconciled curvature with test better than catalogue values. The temperature insensitive bow is attributed to polycarbonate flow/viscoelastic relaxation above Tg and hot relaxation in aluminum, with effects not represented in the elastic models. Edge peel and shear govern initiation risk. Full article

The development of compact, energy-efficient integrated lasers operating at 1.3 µm re-mains a critical focus in silicon photonics, essential for advancing data communications and optical interconnect technologies. This paper presents a numerical study of distributed Bragg reflector (DBR) hybrid III-V-on-silicon lasers, analyzing design trade-offs and optimization strategies based on supermode theory. The III-V section of the design incorporates InAs/(Al)GaAs quantum dots (QDs), which offer improved temperature insensitivity at the cost of more complex III-V/Si optical coupling, due to the high refractive index of (Al)GaAs. Consequently, many current laser designs rely on silicon waveguides with a thickness exceeding 220 nm, which helps coupling but limits their compatibility with standard CMOS technologies. To address this challenge, we perform detailed simulations focusing on 220-nm-thick silicon waveguides. We first examine how the mode profiles jointly depend on the silicon waveguide dimensions and the geometry and composition of the III-V stack. Based on this analysis, we propose a novel epitaxial design that enables effective III-V/Si coupling, with the optical mode strongly confined within the III-V waveguide in the gain section and efficiently transferred to the silicon waveguide in the passive sections. Moreover, the final design is shown to be robust to fabrication-induced deviations from nominal parameters. Full article

The hydrodynamic and reaction characteristics of poly-alpha-olefin (PAO) polymerization in a continuous stirred tank reactor (CSTR) under Eulerian–Eulerian multiphase flow and a finite-rate chemical kinetics model were studied in this paper. A mathematical framework correlating 1-decene conversion with operational and structural parameters was established. Numerical simulations revealed an axial circulation flow pattern driven by combined impellers, with internal coils enhancing heat exchange and flow guidance. The gaseous catalyst, injected below the turbine impeller, achieved rapid dispersion and low gas holdup. The results demonstrated that 1-decene conversion exhibited insensitivity to impeller speed under fully turbulent mixing (mixing time <0.15% of space time), suggesting limited mass transfer benefits from further speed increases. Conversion positively correlated with temperature and space time, albeit with diminishing returns at prolonged durations. Series reactor configurations improved conversion efficiency, though incremental gains decreased with additional units. Optimal reactor design should balance conversion targets with economic factors, including energy consumption and capital investment. These findings provide critical insights into scaling PAO polymerization processes, emphasizing the interplay between reactor geometry, mixing dynamics, and reaction kinetics for industrial applications. Full article