Quality Factor Research Articles

A Novel LCLC Parallel Resonant Circuit for High-Frequency Induction Heating Application

A Novel LCLC Parallel Resonant Circuit for High-Frequency Induction Heating Application

Impact of discharge regulation on zooplankton communities regarding indicator species and their thresholds in the cascade weirs of the Yeongsan River

Discharge regulation in rivers with cascade weirs profoundly alters natural flow dynamics, impacting habitat characteristics and leading to the homogenization of community structure and function. Identifying indicator species and their ecological thresholds is crucial for effectively monitoring and assessing the ecological conditions of regulated river systems. It is also essential for guiding conservation and management efforts. In this study, we investigated the influence of discharge patterns on zooplankton communities in the Yeongsan River, specifically focusing on the effects of flow regulation by cascade weirs. We analyzed the zooplankton community dynamics over a 12-year monitoring period and demonstrated the significance of discharge in shaping river ecosystem dynamics. Species indicator tests and gradient forest modeling were used to identify indicative genera and establish their ecological thresholds under various discharge patterns. Our findings revealed a distinct and significant discharge effect on zooplankton community composition and diversity, independent of water quality and nutrient-related factors. Monsoonal rainfall influenced the discharge patterns, which were categorized into three levels; this classification was further supported by indicator species and their responses. Despite their low abundances limiting clear responses, indicator genera, such as Rotaria and Macrothrix, were shaped by discharge levels. This study highlighted the need to incorporate discharge considerations into river management and conservation strategies to safeguard aquatic biodiversity. Our study provides valuable insights into sustainable river ecosystem management by elucidating the ecological consequences of flow regulation by cascade weirs.

Impact of parenteral nutrition on quality of life, the family and gastrointestinal symptoms in children with intestinal failure.

Intestinal failure (IF) and dependency on parenteral nutrition (PN) are risk factors for lower health-related quality of life (HRQOL) in children. Weaning from PN is a major goal of paediatric IF treatment, however, its impact on HRQOL remains unclear. This study aimed to assess HRQOL, gastrointestinal (GI) symptoms and family impact in children with IF in relation to their need for PN. Data were collected in a cross-sectional study from children with IF and a reference group of healthy children using electronic versions of Paediatric Quality of Life Inventory™ forms. The study included 56 children with IF and 48 healthy children. Parents of children with IF reported significantly lower HRQOL than healthy children (-8.7, p = 0.001). PN dependency did not influence HRQOL scores, but families with children dependent on PN had a lower family impact score than children weaned from PN (49.9 vs. 73.6, p < 0.001). Parents of children in the PN group reported more GI problems than those in the weaned group (-8.1, p = 0.04), and diarrhoea, gas and bloating were common symptoms of IF. GI symptoms varied according to PN dependency and IF aetiology. Multivariate analysis found a significant association between HRQOL and total GI symptom score (parent scores: 0.34, p = 0.02, self-score 0.48, p = 0.02). Children with IF had lower parent-reported HRQOL than healthy children. PN dependency did not affect HRQOL, however, the need for PN had a significant negative impact on family well-being. GI symptoms may negatively impact HRQOL in the IF population.

Interface Characterization of Fusion Bonded Composites Made from Laser-Pretreated Steel and Glass Fiber-Reinforced Thermoplastics Using Electrochemical Impedance Spectroscopy

Material-hybrid designs made of metal and plastic are becoming increasingly important in the automotive and aerospace industries. They place new demands on joining technology in particular. One promising process is the fusion bonding of metals and fiber-reinforced thermoplastics. In this process, the thermoplastic matrix material of the fiber-reinforced composite component is melted and a direct adhesive bond is created with the metallic joining partner. This joining technology has already been extensively studied in the past. In particular, the interface between the joining partners has been identified as a critical factor for the long-term quality of the joint. The interface can be altered by influences during production, such as e-coat process or the effects of harsh environmental conditions during operation like corrosion and thermomechanical loads. Determining the extent of these influences on the interface condition and thus the quality of the joint is difficult, but it is essential to support the use of the joining method in safety-critical areas. Previous investigations of this joining method have mostly been carried out destructively using tensile shear tests and non-destructively using fiber optic and piezo ceramic sensors, but all approaches have only shown limited significance with regard to the metal-plastic interface in detail. Electrochemical impedance spectroscopy (EIS) as a very sensitive measurement method could represent an almost non-destructive and at the same time very sensitive alternative which is currently not reported for this use case in the literature. In previous internal investigations, we found that EIS can be used to measure layer thicknesses of up to 3.5 mm, contrary to the usual use of this test method for characterizing the properties of thin coatings, corrosion behavior and battery performance. In fusion bonding applications, typical material thicknesses of thermoplastics above the interface are around 1.5 mm and are thus well above the usual layer thicknesses of approx. 20 µm to 100 µm for typical EIS applications. This study aims to examine how EIS can be used advantageously for the interface characterization of fusion bonded specimens and up to which extent the EIS can provide a statement about the metal-plastic interface. In this study, a joint of a laser-pretreated steel and a glass fiber-reinforced PA6 is investigated. We measured specimens directly after production, after a treatment similar to an automotive e-coat process and after certain intervals of a salt spray test. Using the Kramers-Kronig transformation, the EIS data was validated and qualitatively analyzed with Nyquist and Bode diagrams, the impedance at 0.1 Hz, the maximum impedance and equivalent circuits. Tensile shear and edge shear test serve as destructive reference tests to determine strength parameters of the joints and evaluate the respective fracture patterns. This opens up the possibility to correlate the results of EIS and destructive measurements. In summary, EIS is suitable for characterizing the metal-plastic interface, even with polymer thicknesses of 1.5 mm, which are comparatively high for EIS. Due to the very low phase angle and the resulting low dielectricity of the glass fiber-reinforced thermoplastic, changes in the impedance data are directly related to the interface condition. The measured impedance spectra could be differentiated with Nyquist and Bode diagrams, the impedance at 0.1 Hz and the maximum impedance.

High mechanical quality factor and high piezoelectric coefficient achieved via acceptor-modified invisible boundary

High mechanical quality factor (Qm) and high piezoelectric coefficient (d33) are desired for high-power applications of piezoelectric ceramics. However, achieving them based on currently known mechanisms has proven challenging because of the tradeoff between Qm and d33. Here we report a surprising finding that this tradeoff can be overcome via acceptor-modified invisible-boundary (IB). High Qm ∼1096 and high d33 ∼337 pC/N were achieved and superior to those of both lead-free and commercial lead-based piezoceramics. The acceptor-modified IB was demonstrated in Fe-doped BaTi0.89Hf0.11O3 ceramics, where the acceptor doping in the IB composition increases Qm by ∼8.6 times and d33 by ∼1.5 times, being different from the acceptor doping effect in morphotropic/polymorphic phase boundary (MPB/PPB) compositions of increasing Qm but decreasing d33. We predict that our finding may also be made in other acceptor-modified IB systems and the obtained high-performance BaTiO3-based piezoceramic could provide an alternative to lead-based piezoceramics in underwater applications.

Relay aided UWOC-SMF-FSO based hybrid link for underwater wireless optical sensor network

The Internet of Underwater Things (IoUTs) connects underwater devices to communicate, sense surroundings, and transmit data. Acoustic communication faces bandwidth limitations, making underwater wireless optical communication-free space optics (UWOC-FSO) hybrid systems a promising alternative. However, maintaining sufficient power budget and signal-to-noise ratio (SNR) is a challenging task, making wavelength translation (WT) from visible to infrared (IR) at the water-fiber-air interface crucial for reliable signal transmission. In this paper, we propose an underwater wireless optical communication-single mode fiber-free space optics (UWOC-SMF-FSO) hybrid link based on a photo-detection, remodulate, and forwarding (PRF) relay and intensity modulation-direct detection (IM/DD) scheme for 8 × 1-Gb/s underwater optical wireless sensor network (UWOSN). The PRF relay is installed at a remotely operated underwater vehicle (ROV) to perform WT from visible range to IR. The performance of the sensors is analyzed for different water bodies and weather conditions of underwater and free space optics channels, respectively using metrics of Bit-error rate (BER) and Quality factor (Q-factor) employing Gamma–Gamma channel model. The simulation results show that forward-error correction (FEC) target BER of 10−4 for sensors is achieved under different water bodies and weather conditions. The results obtained from this study show that the proposed UWOC-SMF-FSO hybrid link is flexible, resilient to adverse channel effects, and can be a potential candidate for implementation of high-speed long-distance future IoUTs.

Novel Multipoint-drive Rotary Actuator for Extraterrestrial Celestial Ultrasonic Driller

Ultrasonic drilling has emerged as a prominent technique in extraterrestrial environments due to its advantageous features. However, its application in extraterrestrial sampling missions is constrained by challenges such as drilling, chip removal efficiency, and high and low temperature adaptability. Addressing these limitations, this study introduces a novel multi-point driven rotary helical longitudinal torsion horn. The initial phase involved a detailed analysis of the actuator’s structure and operational principle. Subsequently, the actuator’s vibration mode and elliptical motion trajectory were validated through finite element simulation. The study further explores a methodology for adjusting the parameters of the helical groove and the displacement amplitude of the impact head. Following the theoretical analysis, prototypes of the actuator and drill were fabricated. Their adaptability to high and low temperatures, as well as their output characteristics, were rigorously tested. Experimental results demonstrate that with an increase in temperature, the dynamic impedance of the actuator initially rises before decreasing, while the mechanical quality factor exhibits the opposite trend. Notably, the concurrent activation of points P1 and P2 significantly enhances the no-load speed, achieving a maximum of 506 revolutions per minute (r/min). Under conditions of power below 35 W and a drilling pressure of 10 N, the drilling speed achieved in basalt is 6.2 millimeters per minute (mm/min). The proposed multipoint-driven actuator can effectively improve the drilling and chip removal efficiency of the driller, which is an important application prospect in future extraterrestrial drilling missions.

A multiscale nonreciprocal thermal radiation multilayer structure based on Weyl semimetal with angle and refractive index detection

In this paper, a multiscale nonreciprocal multilayer structure based on the Weyl semimetal is investigated. This multilayer structure enables the realization of nonreciprocal thermal radiation, as well as angle and refractive index (RI) detection at both θ and -θ angles of the forward and backward scenarios. Scenarios are used to describe the electromagnetic waves (EWs) incident from forward or backward with θ or -θ direction. When the EWs incident from the four scenarios, the localized electric field energy caused by the defect mode triggers a sharp emission peak (EP) within the terahertz range. Moreover, the frequency points of EP will shift regularly with changes in physical quantities. Hence, by precisely locating the frequency points of EP, the angle and RI across four scenarios can be detected. The broadest detection range for angle and RI is 30 degrees∼70 degrees and 1.4–1.9. Furthermore, the best performance of quality factor, the figure of merit, and the detection limit are 508.9, 1.3 degree−1, 4.2 × 10−2 degrees, and 671.7, 63.6 RIU−1, 7.9 × 10−4 RIU, respectively. The concepts and conclusions obtained from this article can offer new possibilities for the construction of novel sensing devices, energy harvesting devices, energy conversion devices, nonreciprocal thermal emitters, etc.

Collaborative online learning in higher education—quality of digital interaction and associations with individual and group-related factors

Collaborative online learning became a necessity for universities during the COVID-19 pandemic. Even though it is known from research that online collaboration is an effective way of learning, digital interaction can be challenging for learners. Group members have to create a high-quality interaction to ensure the success of the collaborative learning process. Based on a theoretical model of collaborative learning, high-quality interaction can be determined with regard to cognitive group activities (prior knowledge activation, transactivity), meta-cognitive group activities (organization of the work process), and relational group activities (group climate, participation and task-related communication). Our study aims to examine how students manage a self-directed collaborative learning setting, how they perceive the process quality of digital interaction and how the interaction quality is related to self-reported outcomes (learning gain and satisfaction). We use a newly developed questionnaire to assess the quality of digital interaction in terms of the aforementioned dimensions. Furthermore, we focus on associations with the beliefs about web-based learning and the ability of perspective-taking at the individual level as well as the sense of community at the group level. We conducted a quantitative study within online university courses that were implemented asynchronously due to the COVID-19 pandemic. N = 298 undergraduate students in teacher education rated the quality of a digital collaborative learning settings (response rate of 72%). The students worked on collaborative tasks autonomously without any guidance from the teacher. We find differences between (meta-)cognitive and relational factors of interaction quality, and differences in the strength of the associations with outcomes and individual and group-related factors. Our study provides insights into students´ collaborative online learning and examines the relationships between different dimensions of group interaction quality and the input and outcome variables. Limitations and areas for further research are discussed.

Understanding ecosystem services of detailed forest and wetland types using remote sensing and deep learning techniques in Northern China

Spanning both temperate and sub-frigid zones, Northeast China boasts typical boreal forests and abundant wetland resources. Because of these attributes, the region is critically significant for global climate regulation, carbon sequestration, and biodiversity preservation. While existing research explores the ecosystem service (ESs) functions of different land cover types, a thoroughly in-depth investigation into the ESs of detailed forest and wetland types is essential. This study addresses this deficiency by combining remote sensing and deep learning techniques, employing a lightweight convolutional neural network (CNN) model and a decision tree for the large-scale classification of forests and wetlands. The ESs of various forest and wetland types—encompassing habitat quality, carbon stock, and soil retention—were assessed during two periods (2008 and 2018) in Heilongjiang Province. Key factors determinants of ESs were identified using the Geodetector tool. The results indicated an overall accuracy of 0.77 in 2008 and 0.78 in 2018 for forest type classification, and 0.88 in 2008 and 0.87 in 2018 for wetland type classification. In particular, the transition from mixed broadleaf forests to mixed coniferous-broadleaf forests dominated changes from 2008 to 2018, probably due to natural succession. Among forest types, Mongolian oak forests exhibited the highest carbon stock and soil retention capacity owing to their rapid growth and deep root systems. Mixed broadleaf forests exhibited superior habitat quality, suggesting minimal disturbance. Habitat quality, carbon stock, and soil retention were found to be significantly influenced by human activity, atmospheric quality, and topographic factors, respectively. By leveraging remote sensing and deep learning methodologies, this study offers a comprehensive analysis of forests and wetlands, elucidating the nuanced ecosystem roles of specific forest and wetland types.

A phantom study on the applicability of a detectability index in ultrasound imaging

The assessment of clinical image quality on ultrasound is currently often subjective. While image quality factors such as contrast response or depth of penetration can be evaluated semi-automatically, the evaluation of high contrast resolution requires test objects with specific inserts. The aim of this study was to evaluate the applicability of image quality metrics which were derived from Linear System Theory in the field of medical ultrasound imaging. Modular Transfer Function (MTF) and noise power spectrum (NPS) were determined on four phantoms. Image quality was assessed using a detectability index for different diameters. One phantom contained a cylinder filled with water, which appears as a circle in the US images. The other three phantoms were homogeneous and consisted of three different materials all based on PVA (polyvinyl alcohol). The basic phantom material was a 10% PVA hydrogel. The two other materials included microplastic spheres and starch to increase echogeneity. NPS and the MTF were determined using MATLAB routines. Two linear US transducers with bandwidths of 2.4–10 and 4–15 MHz were used to show the dependence of the index on the principal frequency of the US wave. The results show that for all phantom materials and object sizes (1–10 mm diameter), the detectability indices decreased with increasing penetration depth (from 6 to 10 cm). In addition, all indices of the higher frequency transducer were higher than those of the lower frequency transducer. When comparing the different phantom materials (PVA, PVA with starch and PVA with microspheres), different mean pixel value (MPV) were found, while the standard deviations for the materials were similar. This enabled us to evaluate the detectability index at different signal-to-noise ratios (SNR). Measures of image homogeneity (coefficient of the variance and variation) showed no significant difference to a commercial phantom (p-values ranging from 0.16 to 1, average p-value 0.5). These results suggest that the concept of a detectability index can also be applied to US imaging.

Trapping light in air with membrane metasurfaces for vibrational strong coupling

Optical metasurfaces can manipulate electromagnetic waves in unprecedented ways at ultra-thin engineered interfaces. Specifically, in the mid-infrared (mid-IR) region, metasurfaces have enabled numerous biochemical sensing, spectroscopy, and vibrational strong coupling (VSC) applications via enhanced light-matter interactions in resonant cavities. However, mid-IR metasurfaces are usually fabricated on solid supporting substrates, which degrade resonance quality factors (Q) and hinder efficient sample access to the near-field electromagnetic hotspots. Besides, typical IR-transparent substrate materials with low refractive indices, such as CaF2, NaCl, KBr, and ZnSe, are usually either water-soluble, expensive, or not compatible with low-cost mass manufacturing processes. Here, we present novel free-standing Si-membrane mid-IR metasurfaces with strong light-trapping capabilities in accessible air voids. We employ the Brillouin zone folding technique to excite tunable, high-Q quasi-bound states in the continuum (qBIC) resonances with our highest measured Q-factor of 722. Leveraging the strong field localizations in accessible air cavities, we demonstrate VSC with multiple quantities of PMMA molecules and the qBIC modes at various detuning frequencies. Our new approach of fabricating mid-IR metasurfaces into semiconductor membranes enables scalable manufacturing of mid-IR photonic devices and provides exciting opportunities for quantum-coherent light-matter interactions, biochemical sensing, and polaritonic chemistry.

Development and evaluation of antibacterial nanofiber membranes via coaxial electrospinning for enhanced air filtration performance

As industrialization intensifies and the population soars, the challenge of air pollution escalates into a pressing concern. Electrospun nanofiber membranes, owing to their distinctive attributes including high specific surface area, porosity, and uniform pore size distribution, have emerged as promising candidates for air filtration. In this study, we successfully prepared ZnO@polyvinylidene fluoride-co-hexafluoropropylene (PVDF-HFP) antibacterial nanofiber membranes through a combined solvothermal and coaxial electrospinning approach. The structure and performance of these nanofiber membranes were systematically modulated by adjusting the shell feeding rate and zinc acetate dihydrate (Zn(Ac)2·2H2O) concentration. Specifically, an increase in the shell feeding rate led to a decrease in fiber diameter, accompanied by the proliferation of nano-beads, thereby contributing to a reduction in membrane pore size. Consequently, a heightened shell feeding rate correlated positively with both filtration efficiency and pressure drop. Furthermore, the incompletely reacted Zn(Ac)2·2H2O enhanced the conductivity of the spinning solution, facilitating a decrease in pore size and enhancing air filtration performance. In summary, when the shell feeding rate was 0.60 mL h−1 and Zn(Ac)2·2H2O concentration was 1.5 wt%, the obtained ZnO@PVDF-HFP nanofiber membrane exhibited superior air filtration performance, with high filtration efficiency of 99.91 %, low pressure drop of 80.70 Pa and noteworthy quality factor of 0.08781 Pa-1. Notably, these membranes sustained their high filtration efficiency and low pressure drop even after 40 min of continuous testing, underscoring their exceptional stability. In addition, the obtained nanofiber membrane exhibited robust antibacterial activity against both Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus), demonstrating their multifaceted potential. Our work not only simplifies the fabrication process of electrospun nanofiber membranes with superior air filtration and antibacterial properties but also highlights their potential as innovative alternatives to conventional air filter materials, poised for diverse practical applications.

Analysis of System Quality Factors &amp; Information Quality with Mediation Variables of Ease of Use To the Success of PT XYZ's E-Procurement

This study examines the influence of system quality and information quality on the success of e-procurement at PT XYZ, with a focus on the mediating role of ease of use. Data were collected from 42 respondents in the purchasing department, all users of the e-procurement system, and analyzed using Partial Least Squares Structural Equation Modeling (PLS-SEM). Key findings include that system quality and information quality both positively affect ease of use. High-quality systems and accurate information make the e-procurement system easier to use. Information quality also directly enhances the success of e-procurement. Additionally, ease of use positively impacts the success of the system, indicating that when users find the system easy to use, its success rate increases. While system quality alone does not directly impact success, it does so when combined with high information quality and ease of use. For PT XYZ, these findings suggest that improving system quality and information quality can significantly enhance e-procurement success. Practical steps include ensuring robust internet connectivity, comprehensive data documentation, timely updates, and clear, accurate information. Simplifying the e-procurement process and enhancing user skills will also contribute to more effective and efficient procurement operations.

Unleashing Giant Förster Resonance Energy Transfer by Bound State in the Continuum.

Förster resonance energy transfer (FRET), driven by dipole-dipole interactions (DDIs), is widely utilized in chemistry, biology, and nanophotonics. However, conventional FRET is ineffective at donor-acceptor distances exceeding 10 nm and measurements suffer from low signal-to-noise ratios. In this study, we demonstrate significant FRET enhancement and extended interaction distances under ambient conditions by utilizing a bound state in the continuum (BIC) mode within a dielectric metasurface cavity. This enhancement is achieved by leveraging the ultrahigh quality factors, minimal material absorption, and nonlocal effects associated with the BIC mode. Spectrally and angularly resolved photoluminescence (PL) lifetime measurements reveal that the BIC mode significantly increases the FRET rate and interaction distance. The FRET rate is enhanced by up to 70-fold, and the interaction distance is significantly boosted by over an order of magnitude, reaching ∼100 nm. These findings offer valuable insights for achieving long-range, high-efficiency FRET and collective DDIs using loss-less dielectric metasurfaces.

Spatial-Temporal Characteristics and Driving Factors of Surface Water Quality in the Jing River Basin of the Loess Plateau

Water quality safety in the water source constitutes a crucial guarantee for public health and the ecological environment. This study undertakes a comprehensive assessment of the water quality conditions within the Jing River Basin of the Loess Plateau, emphasizing the spatial and temporal characteristics, as well as the determinants influencing surface water quality in the Shaanxi section. We utilized data from seven monitoring stations collected between 2016 and 2022, employing an enhanced comprehensive Water Quality Index (WQI) method, redundancy analysis (RDA), and Spearman’s correlation analysis. The results show that the average annual WQI value of the water quality of the Shaanxi section of the Jing River increased from 68.01 in 2016 to 76.18 in 2022, and the river’s water quality has gradually improved, with a significant improvement beginning in 2018, and a series of water quality management policies implemented by Shaanxi Province is the primary reason for the improvement. The river’s water quality has deteriorated slightly in recent years, necessitating stricter supervision of the coal mining industry in the upper section. The river has an average WQI value of 73.70 and is rated as ‘good’. The main pollution indicators influencing the river’s water quality are CODMn, COD, BOD5, NH3-N, and TP. From the upstream to the downstream, the water quality of the river shows a pattern of increasing and then decreasing, among which S4 (Linjing Bridge in Taiping Town) and S5 (Jinghe Bridge) have the best water quality. The downstream part (S6, S7) of the Jing River near the Weihe River has poor water quality, which is mostly caused by nonpoint source contamination from livestock and poultry rearing, agricultural activities, and sewage discharge. Redundancy analysis revealed that the spatial scale of the 2500 m buffer zone best explained water quality changes, and the amount of bare land and arable land in land use categories was the key influencing factor of river water quality.

Integrating Hydrodynamic Modeling with Ecological Risk Assessment for Selecting Sites for Artificial Reef Deployment: Avoiding Coastal Pollution Risks in Kish Island, Persian Gulf

The decline of natural coral reefs has spurred interest in artificial reef construction and reef rehabilitation efforts. However, many restoration programs are failing because of poor water quality and localized pollution factors. This paper examines one etiology of coral restoration failure, highlighting the need for careful site selection based on hydrodynamic, biological, and pollution criteria. Using Kish Island as a case study, we outline a procedure for determining placement of artificial reefs to minimize external pollution impacts, which could be applied to any reef site worldwide. Our integration of computational modeling and geographic information systems enables the tracking of pollution dispersion and increases the power of restoration efforts. The RQ Plume modeling, used alongside compound pollutant modeling, can identify hotspots with the highest potential to degrade marine environments, particularly reefs. Conservation efforts should prioritize pollution mitigation, as seen in the case of sunscreen pollutants at Kish Island, where regulatory action and public education can contribute to reef protection. This comprehensive approach underscores the critical role of water quality in successful reef restoration and conservation strategies.

Bio-inspired sustainable electrospun quantum nanostructures for high quality factor enabled face masks and self-powered intelligent theranostics

Plastic pollution, the energy crisis, and climate change are significant global challenges that threaten human sustainability and social development. Additionally, addressing pollution while simultaneously promoting valorization techniques for the development of effective personal protective equipment to mitigate the transmission of the SARS-CoV-2 virus poses a challenge, particularly in maintaining wearer comfort. Current advancements in intelligent future therapies focus on the incorporation of quantum nanostructures with theranostic capabilities that are compatible with the skin, reduce wear interference, and facilitate easy integration into minimally invasive surgical procedures. To address these challenges, we propose a win–win strategy that enables microplasma technology and high-throughput electrospinning technology to prepare sustainable self-powered angiogenesis inspired ultrafine nanofibers (AINFs). The proposed quantum nanostructure-anchored AINFs are designed to support the development of flex-insensitive white light-emitting optoelectronics (92 % at 500 cycles), COVID-19 face masks of record high-quality factors (0.167 Pa−1 @ PM0.2), and highly compatible large-scale self-powered theranostic capabilities (2694 pmV−1). These innovations align with the urgent demands of a circular economy and foster environmentally sustainable applications within the Internet of Medical Things.

Novel AlN/ScAlN composite film SAW for achieving highly sensitive temperature sensors

Traditional SAW devices, typically made from piezoelectric materials like quartz and lithium niobate (LiNbO3), face significant challenges, such as incompatibility with CMOS processes and a decline in piezoelectric performance at high temperatures. Recently, aluminum nitride (AlN) and scandium-doped AlN (ScAlN) have gained attention as promising materials for high-performance SAW devices due to their high acoustic velocity, thermal stability, and CMOS compatibility. However, the low piezoelectric coefficient of AlN and Sc precipitation in ScAlN films limit their broader application. This study investigates the fabrication and optimization of SAW resonators using AlN/ScAlN composite films to enhance piezoelectric performance while mitigating Sc precipitation. A one-port SAW sensor device was designed based on the composite piezoelectric film, and structural optimization was performed by introducing groove structures to further reduce acoustic energy leakage and improve the quality factor (Q). Temperature sensing experiments were conducted using a peripheral oscillator circuit system. The experimental results demonstrated that the developed composite film SAW resonator exhibited excellent phase noise performance and thermal stability within the oscillator circuit, achieving a phase noise of −135.18 dBc/Hz@1 MHz and a frequency temperature coefficient of −31.07 ppm/°C. These findings confirm the potential of the AlN/ScAlN composite film as a reliable and precise temperature sensor.

A creative hybridization of metamaterial CSRR and multiple-mode resonators for designing a compact wideband bandpass filter for 5G/IOT/WLAN/Wi-Fi 6E applications

Abstract This article presents the design of a metamaterials-based hybrid wideband bandpass filter (WB-BPF) supporting several advanced communication applications. The suggested filter uses multiple-mode resonators (MMRs) and metamaterial complementary split-ring resonators (CSRRs). Coupling frequencies are optimized by stretching the coupled lines parallel on both sides. At the same time, the metamaterial complementary split-ring resonator (CSSR) cells are carefully tuned to improve impedance matching, reduce insertion loss, and broaden the bandwidth. The designed compact-sized bandpass filter offers a Quality factor ( Q L ) of above 1 while maintaining a wide bandwidth of 6150 MHz. The realized structure requires a small physical area of 20.2 × 10 mm2. A parametric study, field distribution analysis, and equivalent circuit model of the proposed hybrid BPF are performed. The resulting filter has an exceptional response with five transmission poles, demonstrating superior performance in the targeted frequency range. This wideband bandpass filter, operating from 3.3 GHz to 9.45 GHz, finds potential applications in the emerging fields of the Internet of Things (IoT), wireless fidelity 6 enhanced (Wi-Fi 6E), and high-speed wireless communications, particularly 5G technology, and 5 GHz wireless local area network (WLAN). This research demonstrates significant advances in the development of bandpass filters, offering compact, high-performance solutions for modern communications systems.