Conventional Devices Research Articles

Pt/β-Ga2O3 Schottky devices enabling 60 Hz half-wave rectification for power-efficient pixel display

Beta-phase gallium oxide, β-Ga2O3, in transistors and diodes has been reported due to its distinctive electrical characteristics, such as wide bandgap, low leakage current, and high breakdown electric field. However, besides such conventional basic devices, more advanced device applications using β-Ga2O3 are always necessary. Here, we report on the dynamic behavior of Pt/β-Ga2O3-based Schottky diode for power-efficient organic light emitting display (OLED). Two Schottky diodes are back-to-back connected in series to form a half-wave rectifier circuit and finally integrated with an OLED diode pixel. When AC voltage is applied to the circuit at a frequency greater than 60 Hz, blinking of the OLED light is indistinguishable to human eyes. By way of the rectifier circuit, the OLED pixel efficiently saves more than 35% of the power that should be consumed by applying DC voltage.

Analysis of the use of tobacco and electronic cigarettes in medical students at a college in a countryside city of the State of São Paulo

Objectives: Smoking remains a public health issue today, despite the efforts of authorities to reduce this habit. Unfortunately, what is witnessed today is similar to what was seen around the time of the introduction of cigarettes in the 1950s, since electronic smoking devices emerged as a new interface for smoking, even presenting themselves as a way to reduce the habit. This present study conducted at a medical school aimed to highlight smoking, whether through conventional cigarettes or electronic smoking devices, among medical students and the reasons why they engage in this behavior. Methods: For this purpose, a descriptive, cross-sectional study with quantitative, descriptive, and statistical analysis of the data was conducted. Results and Conclusion: After analysis, it was observed that smoking initiation mostly occurred during undergraduate studies, with stress being the most commonly cited reason for this habit. It was also inferred that the majority of smokers are male, and that women have a greater intention to quit the habit.

Shaking Table Test Studies on Adaptive-Passive Variable Frequency Gas-Spring DVA for Structural Seismic Response Mitigation

The control performance of a passive dynamic vibration absorber (DVA) is known to be sensitive to its frequency deviation. This study upgrades the conventional device and proposes an adaptive-passive variable frequency gas-spring DVA (APVF-GSDVA) for controlling the structural seismic response, while an adaptive control algorithm is developed that requires only a single input signal. The DVA’s vibration frequency is precisely modulated by adjusting the gas pressure in the gas-spring, aligning it with the inherent frequency of the multi-degree-of-freedom (MDOF) structure. The working principle and control algorithm of the APVF system is introduced and derived in detail, the corresponding gas-spring DVA and implementation are designed, and the configuration of the entire control system is realized. An adaptive variable frequency test scheme is designed and the frequency retuning function of the prototype APVF-GSDVA device installed on an MDOF structure is experimentally validated. The seismic response control effectiveness of the retuned DVA is demonstrated by comparing the detuned DVA, highlighting the necessity of implementing adaptive frequency adjustment of the gas-spring DVA. Experimental findings demonstrate that APVF-GSDVA accurately identifies the inherent frequency of the MDOF structure in ambient excitation, it then adjusts the pressure of the gas-spring according to the frequency-pressure relationship, optimally retuning the DVA. A retuned GSDVA can effectively suppress the structural seismic responses, compared to a detuned DVA, its control effectiveness on peak and RMS responses can be improved by a maximum of nearly 13.5% and 53.3% at a frequency deviation of 10%. Furthermore, results from two “detuning-retuning” test paths with distinct seismic excitations indicate that the retuned DVA exhibits superior control effectiveness, underscoring the significance of the adaptive frequency adjustment function in passive DVAs.

Lateral Phase Heterojunction for Perovskite Microoptoelectronics.

Perovskite heterojunction engineering is the prerequisite but still a deficiency in the fabrication of micro-optoelectronic devices, where the present top-down or bottom-up techniques mainly focus on preparing the vertical heterojunction stacks. Perovskite lateral heterojunction structures generally rely on epitaxial growth, which cannot meet the demands of mass production of micro-devices. Here, a contact diffusion lithography technique is proposed to demonstrate a perovskite lateral phase heterojunction (LPH) polycrystalline film by ion-driven local phase transition. Under the guidance of thermodynamic simulations, methylamine contact and migration collectively promote in situ formation of α-phase formamidine-based perovskite patterns surrounded by δ-phase polymorphs. Spontaneous type-I heterojunction alignment between α- and δ-phases establishes energy funnels in the LPH film to facilitate carrier utilization and radiative recombination. The wide-bandgap δ-phase also serves as the coplanar isolator to achieve local anti-leakage for device integration. Based on the bright and stable LPH pattern layer, the near-infrared microscale perovskite light-emitting diode (micro-PeLED) with impressive device performance is achieved by following conventional device fabrication protocol. The proposed LPH enriches the perovskite heterojunction family, creates a new optoelectronic processing platform, and advances its versatile applications in micro-optoelectronics and photonics.

Smaller is better? Compact vs. Conventional gamma camera for sentinel lymph node localization in patients with breast cancer.

Sentinel lymph node biopsy (SLNB) has been recognized as "the gold standard" for axillary staging in early breast cancer patients with clinically negative lymph nodes, resulting in significant morbidity decrease and quality of life improvement. This study aims to validate the performance of a newly developed handheld portable gamma camera (PGC) produced by Imagensys (Italy), in detecting and locating sentinel lymph nodes (SLNs) during the preoperative and intraoperative phases in breast cancer patients compared to conventional lymphoscintigraphy. Adult female patients with histologically confirmed breast cancer, candidates for surgery and SLNB, were prospectively enrolled in this open-label, pre-marketing clinical trial. All patients underwent pre- operative assessment using both the PGC and conventional lymphoscintigraphy. The performance of the two devices was compared using the Poisson regression model for incidence rate ratios (IRRs). The intrinsic sensitivity of the devices was compared using the Wilcoxon Ranked Sign Test. The utility of PGC during intra-operative procedures was also evaluated. The manoeuvrability of the devices was evaluated using operator-satisfaction questioner. Sixty-eight patients (median age 50 years, BMI 21.4) were enrolled, including two patients with bilateral breast cancer, who underwent SLNB on both axillae. The PGC demonstrated superior preoperative lymph node detection rate (IRR 8.01, 95% CI 6.11-10.50; p < 0.0001) and intrinsic device sensitivity (mean counts per second 409 ± 286 vs. 255 ± 1173 for conventional device, p = 0.0003) compared to the conventional gamma camera. Intra-operative assessment with PGC was performed in 62 patients and no additional lymph nodes were visualised. However, the conventional gamma camera demonstrated superior manoeuvrability (p < 0.0001). The PGC handheld gamma camera showed promising results for preoperative SLN assessment in patients with breast cancer. The limited manoeuvrability may be related to the operator's experience leading to higher inter-operator variability. Appropriate training and frequent use of nuclear medicine and surgical equipment could overcome this limitation.

The Graphene Squeeze-Film Microphone.

Most microphones detect sound-pressure-induced motion of a membrane. In contrast, we introduce a microphone that operates by monitoring sound-pressure-induced modulation of the air compressibility. By driving a graphene membrane at resonance, the gas, that is trapped in a squeeze-film beneath it, is compressed at high frequency. Since the gas-film stiffness depends on the air pressure, the resonance frequency of the graphene is modulated by variations in sound pressure. We demonstrate that this squeeze-film microphone principle can be used to detect sound and music by tracking the membrane's resonance frequency using a phase-locked loop. The squeeze-film microphone potentially offers advantages like increased dynamic range, lower susceptibility to pressure-induced failure and vibration-induced noise over conventional devices. Moreover, microphones might become much smaller, as demonstrated in this work with one that operates using a circular graphene membrane with an area that is more than 1000 times smaller than that of MEMS microphones.

Giant Colloidal Quantum Dot/α-Ga2O3 Heterojunction for High Performance UV-Vis-IR Broadband Photodetector.

Broadband optoelectronics, which extend from the UV to IR regions, are crucial for imaging, autonomous driving, and object recognition. In particular, photon detection efficiency relies significantly on semiconductor properties, such as absorption coefficients and electron-hole pair generation rate, which can be optimized by designing a suitable p-n junction. In this study, we devise giant PbS colloidal quantum dots (G-PbS CQDs) that exhibit high absorption coefficients and broadband absorption. To leverage these exceptional optical properties, we combine G-PbS CQDs with an ultrawide-bandgap semiconductor, α-Ga2O3, and create an efficient G-PbS CQD/α-Ga2O3 heterojunction photodetector that exhibits high performance across the UVC-vis-NIR spectrum range. The resultant heterojunction facilitates efficient electron-hole pair separation at the G-PbS CQD/α-Ga2O3 heterojunction. Furthermore, we utilize transparent graphene electrodes to overcome the limitations of conventional transistor-type device structures and the substantial optical losses induced by opaque metal electrodes. This strategy maximizes the light-collection area and results in an approximately 3-orders of magnitude higher responsivity (55.5 A/W) and specific detectivity (1.66 × 1013 Jones) compared to devices with opaque metal electrodes.

Ultra-sensitive dengue NS1 protein detection via asymmetric source-drain, heterojunction and dual-dielectric cavities in a uniform tunnel FET biosensor

In this paper, we present a unique Asymmetric Source-Drain Heterojunction Dual-Dielectric Uniform Tunnel Field Effect Transistor (A-SD-HJ-DD-UTFET) based biosensor tailored for the early detection of dengue NS1 protein during the acute phase of infection offering early diagnosis and potentially life-saving intervention. The proposed biosensor design features simplified fabrication, a narrow drain region, and a dual material control gate, enhancing specificity and sensitivity for dengue virus detection. Using a heterojunction configuration, this device optimizes electron flow for improved detection accuracy. The roles of Tunnel Gate (TG) and Auxiliary Gate (AG) are studied in terms of band energy, electric field, electrostatic potential, and other sensitivity parameters. Sentaurus TCAD tool is utilized for analyzing the characteristics of the proposed A-SD-HJ-DD-UTFET biosensor. Simulation results indicate that the designed A-SD-HJ-DD-UTFET biosensor achieves a superior Subthreshold Swing (SS) of 15.4 mV/dec and an enhanced ION/IOFF sensitivity of about 2.25 × 10¹¹ with a maximum ON and minimum OFF state currents of 2.28 × 10–4 A/μm and 1.28 × 10–16 A/μm respectively for detecting NS1 protein of dengue. Additionally, it boasts a high switch ratio in the order of 1012. The proposed biosensor outperforms conventional devices, including the state-of-the-art Junctionless (JL)-TFET biosensors. The superior electrical characteristics of the proposed A-SD-HJ-DD-UTFET biosensor make it a promising device for early detection of the dengue NS1 protein, providing a potent solution for mitigating the spread of dengue infections.

Enhancing the performance of Ga2O3 FinFETs through double fin channels and buried oxide

In this study, double fin channels and buried oxide has been implemented on Ga2O3 FinFET. Exhaustive simulations have been performed to study the performance of the proposed device and its comparison has been drawn with the device with only double fin channels without buried oxide, and the conventional FinFET. Various device characteristics such as output and transfer characteristics etc., have been studied and several figure of merits (FoMs) such as transconductance, parasitic capacitances, gain bandwidth product, intrinsic delay etc., have also been obtained. Further, the inverter has been designed using all the devices under consideration. It has been demonstrated that the inverter using the proposed device exhibits excellent characteristics in terms of significant improvement in key metrics such as noise margin, transient response etc., as compared to the inverter using conventional devices. The current study also lays the groundwork for designing various high-performance circuits for ultra-high frequency applications.

Combined inertial and pleated filter for efficient PM1.0 separation and sampling

A reliable measuring method of particulate matter less than 1 µm (PM1.0) is essential to clarify the correlation between the PM1.0 mass concentration and the impact of human health, and to establish effective PM1.0 control strategies. In this study, a new PM1.0 sampler, the inertial filter/pleated filter sampler (I/P sampler), was designed to collect particles larger than 1 μm in the inertial filter and PM1.0 in the pleated filter during sampling. The inertial filter with small filtration area successfully separated particles larger than 1 μm by reducing diffusion and increasing inertia, while the pleated filter with large filtration area efficiently collected PM1.0 by lowering the filtration velocity to promote diffusional collection.The I/P sampler was used to measure PM1.0 mass concentration through field tests, with results compared with those of conventional sampling devices for PM1.0 (cyclone sampler, cascade impactor, beta attenuation monitor [BAM], and EPA-approved federal reference method [E-FRM] sampler). Field measurements indicated a good correlation between the I/P sampler and conventional samplers, with regression slopes ranging from 0.90 to 1.07 in summer and 1.10 to 1.37 in winter. In addition, the measured mass concentrations decreased in the order of I/P sampler, cyclone sampler, E-FRM sampler, BAM, and cascade impactor.

Does preprocedural ultrasound prior to lumbar neuraxial anesthesia or analgesia increase first-pass success in adults with obesity? A systematic review.

Preprocedural ultrasound (PPU) reduces the risk of technical failure in non-obese patients and when technical difficulty is predicted. We conducted this review to determine if PPU improves first-pass needle insertion success for neuraxial anesthesia in patients with obesity. We conducted a systematic review without meta-analysis, due to the small number of included studies. The study protocol was registered (PROSPERO: CRD42022368271). We conducted searches in MEDLINE, Embase, PubMed, and Cochrane Library from January 1, 1980 to October 1, 2022 for peer-reviewed randomized controlled or observational studies comparing PPU versus landmark techniques in patients with body mass index >30 kg/m2. The quality of evidence was assessed using the revised Cochrane risk-of-bias tool for randomized trials and Grading of Recommendations Assessment, Development, and Evaluation approach. There were nine randomized controlled studies, comprising 866 patients having lumbo-sacral neuraxial techniques. Three studies utilized a small handheld ultrasound device called Accuro™ and six utilized non-handheld ultrasound devices. Certainty of evidence was low for improving the first-pass success rate. There was evidence (moderate certainty) that PPU decreased number of passes, increased first insertion attempt success, and reduced number of insertion attempts. There was no evidence that PPU affected identifying time, needling time, or overall procedural time. There was no evidence that PPU influenced procedural failure rate (very low certainty evidence) and insufficient evidence to suggest that artificial intelligence-supported handheld devices were superior to conventional ultrasound devices. In patients with obesity, there is evidence of very-low to moderate certainty that PPU improves markers of insertion success, with no indication of increased adverse effects. PPU should be used to reduce attempts. Further studies adhering to standardized outcome definitions are required for definitive recommendations. The study protocol was registered on the International Prospective Register of Systematic Reviews (PROSPERO: CRD42022368271).

Enhancement of reactive oxygen species production by ultra-short electron pulses.

The development of laser-driven accelerators-on-chip has provided an opportunity to miniaturize devices for electron radiotherapy delivery. Laser-driven accelerators produce highly time-compressed electron pulses, on the 100 fs to 1 ps scale. This delivers electrons at high peak power yet low average beam current compared with conventional delivery devices, which generate pulses of approximately 3 µs. The biophysical effects of this time structure, however, are unclear. Here, we use a Monte Carlo simulation approach to explore the effects of the electron beam time structure on the production of reactive oxygen species (ROS) in water. Our results show a power law increase in the generation of hydroxyl ions per deposited electron with decreasing pulse length over the pulse length range of 10 µs to 100 fs. Similar trends were observed for hydrogen peroxide, superoxide, hydroperoxyl, hydronium and solvated electrons. In practical terms, this indicates a fourfold increase in the efficiency of free radical production for sub-picosecond pulses, relative to that of conventional microsecond pulses, for the same number of deposited electrons.

Middle Ear Malformations

Middle ear malformations (MEMs) represent a diverse group of congenital anomalies with significant implications for auditory function. These malformations, which occur in approximately 0.5 to 3% of conductive hearing loss cases, can arise from various genetic and environmental factors. They often manifest unilaterally and may occur in isolation or as part of a syndromic condition. MEMs are closely associated with abnormalities of the external ear and less frequently with inner ear anomalies.Embryologically, the middle ear develops from the first and second pharyngeal arches, with interactions between the ectoderm and endoderm contributing to the formation of essential structures such as the tympanic membrane, ossicles and Eustachian tube. Disruptions in these developmental processes can lead to a spectrum of MEMs, ranging from minor defects to severe malformations affecting multiple middle ear components.Clinical management of MEMs requires a multidisciplinary approach, involving otolaryngologists, pediatricians, and audiologists. Early intervention with appropriate hearing aids, including conventional hearing aids and bone conduction devices, is essential to mitigate the impact of conductive hearing loss on speech and language development, particularly in children.Surgical planning involves comprehensive preoperative assessment, including high-resolution computed tomography imaging to evaluate middle ear anatomy, the facial nerve course, and vascular anomalies. Traditional surgical approaches such as stapesplasty and tympanoplasty remain mainstays for correcting specific middle ear defects, while advances in technology have expanded the role of active middle ear implants in treating special cases.In conclusion, MEMs represent a heterogeneous group of congenital anomalies with diverse etiologies and clinical implications. A thorough understanding of their embryological basis, genetic underpinnings, and surgical management strategies is crucial for optimizing outcomes in affected individuals.

Novel super stack passivation in AlGaN/GaN HEMT for power electronic applications

Abstract A super-stack passivation technique is proposed for an AlGaN/GaN HEMT in order to improve the breakdown voltage and cutoff frequency. The performance of the proposed technique is benchmarked against a conventional GaN HEMT. The analysis and investigation are carried out using Technology Computer-Aided Design (TCAD). The simulation results are validated with experimental data. It is observed that the breakdown voltage of the conventional and proposed devices is 356V and 449V, respectively. In contrast to the conventional device, the breakdown voltage of the proposed device is improved by 21%. This is the manifestation of the suppression of the electric field by the super-stack passivation technique in the proposed device. Furthermore, it is also observed that the Johnson’s figure of merit in the proposed GaN-HEMT is also improved.

Machine learning for predictive AAC: Improving speech and gesture-based communication systems

Augmentative and alternative communication (AAC) systems play a crucial role in supporting individuals with severe communication disabilities by providing accessible means of expression and engagement. However, many conventional AAC devices rely on manual input or basic predictive functions, which can limit communication efficiency and responsiveness. The application of machine learning (ML) to AAC offers new opportunities to enhance these systems, enabling them to provide faster, more accurate, and contextually relevant communication assistance. Advances in ML, particularly in predictive text, speech recognition, and gesture interpretation, allow AAC systems to adapt more intuitively to user needs, predicting intent based on usage patterns and multimodal data, such as voice and gestures. Current research highlights the potential of ML to address key gaps in AAC technology by creating more responsive, personalized systems that align with individual user behaviours. This study proposes a novel ML framework designed to integrate these capabilities, promising improvements in communication speed, user autonomy, and accuracy. By addressing the challenges and limitations of traditional AAC devices, this research aims to advance accessible communication solutions that empower users and improve quality of life.

A wearable and stretchable dual-wavelength LED device for home care of chronic infected wounds.

Phototherapy can offer a safe and non-invasive solution against infections, while promoting wound healing. Conventional phototherapeutic devices are bulky and limited to hospital use. To overcome these challenges, we developed a wearable, flexible red and blue LED (r&bLED) patch controlled by a mobile-connected system, enabling safe self-application at home. The patch exhibits excellent skin compatibility, flexibility, and comfort, with high safety under system supervision. Additionally, we synthesized a sprayable fibrin gel (F-gel) containing blue light-sensitive thymoquinone and red light-synergistic NADH. Combined with bLED, thymoquinone eradicated microbes and biofilms within minutes, regardless of antibiotic resistance. Furthermore, NADH and rLED synergistically improved macrophage and endothelial cell mitochondrial function, promoting wound healing, reducing inflammation, and enhancing angiogenesis, as validated in infected diabetic wounds in mice and minipigs. This innovative technology holds great promise for revolutionizing at-home phototherapy for chronic infected wounds.

Surfactant monolayers at oil–water interfaces. Behavior upon compression and relation to emulsion stability

AbstractSurfactant monolayers modify the surface tension of fluid surfaces, and they confer to the surfaces a resistance to mechanical perturbances, such as compression or dilatation. The resistance can be characterized by elastic and viscous moduli, that affect the phenomena involving the motion of liquid surfaces such as wetting, two‐phase flow, foaming and emulsification, rheology and stability of foams and emulsions. Some of these phenomena, for instance coalescence of bubbles or drops, are extremely rapid, and although coalescence seems correlated with the elastic compression modulus, no quantitative comparison has been made. Indeed, this modulus is frequency dependent, and cannot be measured by most conventional devices at the short timescales during which coalescence events occur. In this paper, we first review the current understanding on foam and emulsion stability, highlighting the role of surface rheology in the stability of these systems, important for their formulation. We present tension measurements for various surfactant systems, nonionic and cationic, at oil–water interfaces. We show calculations of the high frequency elastic modulus using the Gibbs adsorption equation and compare the results to previous measurements at air–water interfaces. The moduli measured imposing a rapid expansion of the monolayers are consistently smaller, in particular at oil–water interfaces. We discuss the possible origin of the differences between the two types of interfaces.

Energy conversion and transport in molecular-scale junctions

Molecular-scale junctions (MSJs) have been considered the ideal testbed for probing physical and chemical processes at the molecular scale. Due to nanometric confinement, charge and energy transport in MSJs are governed by quantum mechanically dictated energy profiles, which can be tuned chemically or physically with atomic precision, offering rich possibilities beyond conventional semiconductor devices. While charge transport in MSJs has been extensively studied over the past two decades, understanding energy conversion and transport in MSJs has only become experimentally attainable in recent years. As demonstrated recently, by tuning the quantum interplay between the electrodes, the molecular core, and the contact interfaces, energy processes can be manipulated to achieve desired functionalities, opening new avenues for molecular electronics, energy harvesting, and sensing applications. This Review provides a comprehensive overview and critical analysis of various forms of energy conversion and transport processes in MSJs and their associated applications. We elaborate on energy-related processes mediated by the interaction between the core molecular structure in MSJs and different external stimuli, such as light, heat, electric field, magnetic field, force, and other environmental cues. Key topics covered include photovoltaics, electroluminescence, thermoelectricity, heat conduction, catalysis, spin-mediated phenomena, and vibrational effects. The review concludes with a discussion of existing challenges and future opportunities, aiming to facilitate in-depth future investigation of promising experimental platforms, molecular design principles, control strategies, and new application scenarios.

Asymmetric Aramid Aerogel Composite with Durable and Covert Thermal Management via Janus Heat Transfer Structure.

Warmth preservation in cold climates requires a long-term heat supply. Conventional thermal devices usually deliver excessive heat and have difficulty preventing heat loss. Herein, to achieve durable thermal comfort, an asymmetric composite (AAAC) is devised through vacuum-filtrating silver nanowires (AgNWs) onto the surface of a poly(ethylene glycol) (PEG)-infiltrated aramid nanofiber aerogel. AgNW e-skin can transfer strong Joule heat to the back side of the AAAC, where the infused PEG further stores thermal energy by phase transition and then releases it to the body constantly after the power is off. Base on the Janus structure, the AAAC can provide thermotherapy for human waists and knees, holding a suitable temperature range of 37-39 °C for 5-8 min without a heat source. In addition, low infrared emissivity (0.064-0.315) of e-skin allows the AAAC to conceal thermal targets while producing Joule heat, which achieves comfortable and safe thermal management in multiple occasions including daily life and military warfare.

3D-printed microfluidic and millifluidic devices for cell culture and mechanotransduction studies: A review

The practice of conventional cell culture techniques affects the quality of biological research in mechanobiology by not replicating the cell’s microenvironment adequately. Microfluidic devices resembling 3D in vivo cell culture offer viable alternatives for mechanobiology studies and other applications including cell screening, cell separation, and point-of-care diagnostics. This review highlights recent advances in additive manufacturing (AM) to fabricate microfluidic and millifluidic devices through fast design iterations and cost reduction compared with conventional device manufacturing. Key advances in AM technologies such as fused deposition modeling (FDM), stereolithography apparatus (SLA), and digital light processing (DLP) have allowed the direct manufacture of complex microfluidic devices with master molds and sacrificial structures using multiple material components. Currently, available 3D printed devices for the precise fabrication of milli- and microfluidic devices, essential to mimicking the cellular microenvironment, while economically reducing production costs by eliminating expensive clean-room environments and reducing material waste are highlighted.