Search Results (2,091)

Sea surface roughness (SSR) retrieval is a frontier topic in the field of ocean remote sensing, and SSR retrieval based on multi angle, passive, visible spectrum remote sensing images has been proven to have potential applications. Traditional multi angle retrieval models ignored the nonlinear relationship between radiation and digital signals, resulting in low accuracy in SSR retrieval using visible spectrum remote sensing images. Therefore, we analyze the transmission characteristics of signals and random noise in sea surface imaging, establish signals and noise transmission models for typical sea surface imaging visible spectrum remote sensing systems using Complementary Metal Oxide Semiconductor (CMOS) and Time Delay Integration-Charge Coupled Device (TDI-CCD) sensors, and propose a model for SSR retrieval using multi angle passive visible spectrum remote sensing images. The proposed model can effectively suppress the noise behavior in the imaging link and improve the accuracy of SSR retrieval. Simulation experiments show that when simulating the retrieval of multi angle visible spectrum images obtained using CMOS or TDI-CCD imaging systems with four SSR levels of 0.02, 0.03, 0.04, and 0.05, the proposed model relative errors using two angles are decreased by 4.0%, 2.7%, 2.3%, and 2.0% and 6.5%, 4.3%, 3.7%, and 3.2%, compared with the relative errors of the model without considering noise behavior, which are 7.0%, 6.7%, 7.8%, and 9.0% and 9.5%, 8.3%, 9.0%, and 10.2%. When using more fitting data, the relative errors of the model were decreased by 5.0%, 2.7%, 2.5%, and 2.0% and 7.0%, 5.0%, 4.3%, and 3.2%, compared with the relative errors of the model without considering noise behavior, which are 8.5%, 7.0%, 8.0%, and 9.4%, and 10.0%, 8.7%, 9.3%, and 10.0%. Full article

In this study, a hybrid sensor-based electronic nose circuit was developed using eight metal-oxide semiconductors and 14 quartz crystal microbalance gas sensors. This study included 100 participants: 60 individuals diagnosed with lung cancer, 20 healthy nonsmokers, and 20 healthy smokers. A total of 338 experiments were performed using breath samples throughout this study. In the classification phase of the obtained data, in addition to traditional classification algorithms, such as decision trees, support vector machines, k-nearest neighbors, and random forests, the fuzzy logic method supported by the optimization algorithm was also used. While the data were classified using the fuzzy logic method, the parameters of the membership functions were optimized using a nature-inspired optimization algorithm. In addition, principal component analysis and linear discriminant analysis were used to determine the effects of dimension-reduction algorithms. As a result of all the operations performed, the highest classification accuracy of 94.58% was achieved using traditional classification algorithms, whereas the data were classified with 97.93% accuracy using the fuzzy logic method optimized with optimization algorithms inspired by nature. Full article

Resistive switching (RS) phenomena are nowadays one of the most studied topics in the area of microelectronics. It can be observed in Metal–Insulator–Metal (MIM) structures that are the basis of resistive switching random-access memories (RRAMs). In the case of commercial use of RRAMs, it is beneficial that the applied materials would have to be compatible with Complementary Metal-Oxide-Semiconductor (CMOS) technology. Fabricating methods of these materials can determine their stoichiometry and structural composition, which can have a detrimental impact on the electrical performance of manufactured devices. In this study, we present the influence of the Ar/N₂ ratio during reactive magnetron sputtering of titanium nitride (TiN) electrodes on the resistive switching behavior of MIM devices. We used silicon oxide (SiOx) as a dielectric layer, which was characterized by the same properties in all fabricated MIM structures. The composition of TiN thin layers was controlled by tuning the Ar/N₂ ratio during the deposition process. The fabricated conductive materials were characterized in terms of chemical and structural properties employing X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis. Structural characterization revealed that increasing the Ar content during the reactive sputtering process affects the crystallite size of the deposited TiN layer. The resulting crystallite sizes ranged from 8 Å to 757.4 Å. The I-V measurements of fabricated devices revealed that tuning the Ar/N₂ ratio during the deposition of TiN electrodes affects the RS behavior. Our work shows the importance of controlling the stoichiometry and structural parameters of electrodes on resistive switching phenomena. Full article

Discrete Silicon Carbide Metal-Oxide-Semiconductor Field-Effect Transistors (SiC MOSFETs) are characterized by their lower parasitic parameters and single-chip design, enabling them to achieve even faster switching speeds. However, the rapid rate of change in voltage (dv/dt) and current (di/dt) can lead to overshoot and oscillation in both voltage and current, ultimately limiting the performance of high-frequency operations. To address this issue, this paper presents a high-switching-frequency motor controller that utilizes discrete SiC MOSFETs. To achieve a high switching frequency for the controller while minimizing current oscillation and voltage overshoot, a novel electronic system architecture is proposed. Additionally, a passive driving circuit is designed to suppress gate oscillation without the need for additional control circuits. A new printed circuit board (PCB) laminate stack featuring low parasitic inductance, high current conduction capacity, and efficient heat dissipation is also developed using advanced wiring technology and a specialized heat dissipation structure. Compared to traditional methods, the proposed circuit and bus design features a simpler structure, a higher power density, and achieves a 13% reduction in current overshoot, along with a 15.7% decrease in switching loss. The silicon carbide (SiC) controller developed from this research has successfully undergone double-pulse and power testing. The results indicate that the designed controller can operate reliably over extended periods at a switching frequency of 50 kHz, achieving a maximum efficiency of 98.2% and a power density of 9 kW/kg (10 kW/L). The switching frequency and quality density achieved by the controller have not been observed in previous studies. This controller is suitable for use in the development of new energy electrical systems. Full article

A method was developed for plasma-enhanced chemical vapor deposition of β-Ga₂O₃:Zn thin films with the possibility of pre-purifying precursors. The structural and electrically conductive properties of β-Ga₂O₃:Zn thin films were studied. Increasing the temperature of the Zn source (T_Zn) to 220 °C led to the formation of Ga₂O₃ films with a Zn concentration of 4 at.%, at T_Zn = 230 °C [Zn] = 6 at.% and at 235 °C. [Zn] = 8 at.% At T_Zn = 23 °C, the films corresponded to the β-Ga₂O₃ phase and were single-crystalline with a surface orientation of (–201). As T_Zn increased, the polycrystalline structure of β-Ga₂O₃ films with a predominant orientation of (111) was formed. The introduction of Zn led to the formation of a more developed microrelief of the surface. Raman spectroscopy showed that a small concentration of impurity atoms tended to replace gallium atoms in the oxide lattice, which was also confirmed by the Hall measurements. The concentration of charge carriers upon the introduction of Zn, which is a deep acceptor, decreased by 2–3 orders of magnitude, which mainly determined the decrease in the films’ resistivity. The resulting thin films were promising for the development of high-resistivity areas of β-Ga₂O₃-based devices. Full article

The instability of many volatile organic compounds (VOCs) limits their usage in different fragrance carriers and products. In scratch-and-sniff applications, VOCs are bound so strongly that release cannot happen without an external trigger. On the other hand, other fixatives like cyclodextrins release unstable volatile molecules too rapidly. We engineered biodegradable gelatin films whose release profile can be tuned by glycerol plasticization and alkaline protease degradation. Digitalized VOC release profiles acquired with the described near-real-time analysis toolkit are digital twins that replicate the behavior of the evaluated films in silico. Seven formulations were cast from 10% gelatin containing D-limonene, glycerol (5%, 20%), protease-C 30 kU mL⁻¹, and samples with additional water to establish a higher hydromodule for protease catalytic activity. Release profiles were monitored for nine days at 23 ± 2 °C in parallel by metal-oxide semiconductor (MOS) e-noses, gravimetric weight loss, and near-infrared measurements (NIR). These continuous measurements were cross-checked with gel electrophoresis, FTIR spectroscopy, hardness tests, and sensory intensity ratings. Results showed acceleration of VOC release by enzymatic treatment during the first days, as well as overall impact on the release profile. Differences in low and high glycerol films were observed, and principal component analysis of NIR spectra separated low and high glycerol groups, mirroring the MOS and FTIR data. Usability of MOS data was explored in comparison to more biased and subjective intensity results from sensory panel evaluation. Overall, the created toolkit showed good cross-checked results and enabled the possibility for close to real-time analysis for bio-based VOC carriers. Full article

This review examines the emerging role of manganese-based nanoparticles (Mn-NPs) in detecting heavy metal pollutants in environmental matrices. Heavy metals such as cadmium, lead, zinc, and copper pose serious environmental and health concerns due to their tendency to persist in ecosystems and accumulate in living organisms. As a result, there is a growing need for reliable methods to detect and remove these pollutants. Manganese nanoparticles offer unique advantages that scientists could consider as replacing other metal nanoparticles, which may be more expensive or more toxic. The physicochemical properties of Mn-NPs—including their multiple oxidation states, magnetic susceptibility, catalytic capabilities, and semiconductor conductivity—enable the development of multi-modal sensing platforms with exceptional sensitivity and selectivity. While Mn-NPs exhibit inherently low electrical conductivity, strategies such as transition metal doping and the formation of composites with conductive materials have successfully addressed this limitation. Compared to noble metal nanoparticles (Au, Ag, Pd) and other base metal nanoparticles (Bi, Fe₃O₄), Mn-NPs demonstrate competitive performance without the drawbacks of high cost, complex synthesis, poor distribution control, or significant aggregation. Preliminary studies retrieved from the Scopus database highlight promising applications of manganese-based nanomaterials in electrochemical sensing of heavy metals, with recent developments showing detection limits in the sub-ppb range. Future research directions should focus on addressing challenges related to scalability, cost-effectiveness, and integration with existing water treatment infrastructure to accelerate the transition from laboratory findings to practical environmental applications. Full article

The bulk linearization technique is a design strategy used to extend the linear region of a metal oxide semiconductor field effect transistor (MOSFET) by increasing its saturation voltage through a composite structure and a gate biasing circuit. This allows us to develop compact and flexible pseudo-resistor elements for integrated circuit designs. In this paper we propose a new simple yet effective design approach, focused on the biasing circuit, that optimizes area, offset, and power consumption without altering the design complexity of the original solution. Post-layout simulations verify the presented design strategy, which is then applied for designing a band-pass filter for neural action potential acquisition. Results of harmonic distortion and noise analysis strengthen the validity of the proposed strategy. Full article

Integrating two-dimensional transition-metal dichalcogenides with graphene is attractive for low-power memory and neuromorphic hardware, yet sequential wet transfer leaves polymer residues and high contact resistance. We demonstrate a complementary metal–oxide–semiconductor (CMOS)-compatible, transfer-free route in which an atomically thin amorphous MoS₂ precursor is RF-sputtered directly onto chemical vapor-deposited few-layer graphene and crystallized by confined-space sulfurization at 800 °C. Grazing-incidence X-ray reflectivity, Raman spectroscopy, and X-ray photoelectron spectroscopy confirm the formation of residue-free, three-to-four-layer 2H-MoS₂ (roughness: 0.8–0.9 nm) over 1.5 cm × 2 cm coupons. Lateral MoS₂/graphene devices exhibit reproducible non-volatile resistive switching with a set transition (SET) near +6 V and an analogue ON/OFF ≈2.1, attributable to vacancy-induced Schottky-barrier modulation. The single-furnace magnetron sputtering + sulfurization sequence avoids toxic H₂S, polymer transfer steps, and high-resistance contacts, offering a cost-effective pathway toward wafer-scale 2D memristors compatible with back-end CMOS temperatures. Full article

Electrochemical sensing arrays enable the spatial study of dopamine levels throughout brain slices, the diffusion of electroactive molecules, as well as neurotransmitter secretion from single cells. The integration of complementary metal-oxide semiconductor (CMOS) devices in the development of electrochemical sensing devices enables large-scale parallel recordings, providing beneficial high-throughput for drug screening studies, brain–machine interfaces, and single-cell electrophysiology. In this paper, an electrochemical sensor capable of recording at 40,000 frames per second using a CMOS sensor array with 1024 electrochemical detectors and a custom field-programmable gate array data acquisition system is detailed. A total of 1024 on-chip electrodes are monolithically integrated onto the designed CMOS chip through post-CMOS fabrication. Each electrode is paired with a dedicated transimpedance amplifier, providing 1024 parallel electrochemical sensors for high-throughput studies. To support the level of data generated by the electrochemical device, a powerful data acquisition system is designed to operate the sensor array as well as digitize and transmit the output of the CMOS chip. Using the presented electrochemical sensing system, both dopamine and hydrogen peroxide diffusions across the sensor array are successfully recorded at 40,000 frames per second across the 32 × 32 electrochemical detector array. Full article

The poor selectivity of metal oxide semiconductor sensors is a major constraint to their application in the detection of chemical warfare agents. We prepared a (Pt+Pd+Rh)@Al₂O₃/(Pt+Rh)-WO₃ sensor by using (Pt+Pd+Rh)@Al₂O₃ as a catalytic film material and (Pt+Rh)-WO₃ as a gas-sensitive film material. Using temperature dynamic modulation, the (Pt+Pd+Rh)@Al₂O₃/(Pt+Rh)-WO₃ sensor was realised to improve the selectivity for mustard. Due to the catalytic effect of the (Pt+Pd+Rh)@Al₂O₃ catalytic film on mustard, mustard was able to be catalytically generated into mustard sulphoxide after passing through the (Pt+Pd+Rh)@Al₂O₃ catalytic film. Under a certain temperature dynamic modulation, the mustard concentration on the surface of the (Pt+Rh)-WO₃ gas-sensitive film showed an increase and then a decrease. Since the resistance response of the (Pt+Rh)-WO₃ gas-sensitive film to mustard was much higher than that of mustard sulphoxide, the change in the resistance of the (Pt+Rh)-WO₃ gas-sensitive film was mainly determined by the change in the concentration of mustard, which led to the peak signal in the curve of its resistance response to mustard. The experimental results showed that the (Pt+Pd+Rh)@Al₂O₃/(Pt+Rh)-WO₃ sensor had peak signals in the resistance response to mustard only, and not in the resistance response to 12 interfering gases, such as carbon monoxide. Full article

Since the early days of silicon manufacturing, hydrogen gas treatment has been used to control the defect concentrations. Its beneficial effect can be enhanced using hydrogen plasma as a source of active atomic hydrogen. Hydrogen plasma modification of c-Si surface can be challenging because the plasma can induce precursors of defect centers that can persist at the interface and/or grown oxide after subsequent thermal oxidation. In the present study, we investigate nanoscale silicon dioxides with thicknesses in the range of 6–22 nm grown at low temperature (850 °C) in dry oxygen on radio frequency (RF) hydrogen plasma-treated silicon surface. The properties of these oxides are compared to oxides grown following standard Radio Corporation of America (RCA) Si technology. Electroreflectance measurements reveal better interface quality with enhanced electron mobility and lowered oxidation-induced stress levels when the oxides are grown on H-plasma modified c-Si substrates. These results are in good accordance with the reduced defect concentration established from the analysis of the current–voltage (I-V) and multifrequency capacitance–voltage (C-V) characteristics of metal-oxide-semiconductor (MOS) capacitors incorporating the Si-SiO₂ structures. The study proves the potential of hydrogen plasma treatment of Si prior to oxidation for various Si-based applications. Full article

Precise time interval generation is a cornerstone of modern measurement, automation, and distributed control systems, particularly within Internet of Things (IoT) architectures. This paper presents the design, implementation, and evaluation of a low-cost and high-precision time interval generator based on Complementary Metal-Oxide Semiconductor (CMOS) logic counters (Integrated Circuit (IC) IC 7493 and IC 4017) and inverter-based crystal oscillators (IC 74LS04). The proposed system enables frequency division from 1 MHz down to 1 Hz through a cascade of binary and Johnson counters, enhanced with digitally controlled multiplexers for output signal selection. Unlike conventional timing systems relying on expensive Field-Programmable Gate Array (FPGA) or Global Navigation Satellite System (GNSS)-based synchronization, this approach offers a robust, locally controlled reference clock suitable for IoT nodes without network access. The hardware is integrated with Arduino and ESP32 microcontrollers via General-Purpose Input/Output (GPIO) level interfacing, supporting real-time timestamping, deterministic task execution, and microsecond-level synchronization. The system was validated through Python-based simulations incorporating Gaussian jitter models, as well as real-time experimental measurements using Arduino’s micros() function. Results demonstrated stable pulse generation with timing deviations consistently below ±3 µs across various frequency modes. A comparative analysis confirms the advantages of this CMOS-based timing solution over Real-Time Clock (RTC), Network Time Protocol (NTP), and Global Positioning System (GPS)-based methods in terms of local autonomy, cost, and integration simplicity. This work provides a practical and scalable time reference architecture for educational, industrial, and distributed applications, establishing a new bridge between classical digital circuit design and modern Internet of Things (IoT) timing requirements. Full article

In recent years, electrospinning technology has sparked a revolution in the nanoengineering of gas-sensing materials. Nanofibers based on metal oxide semiconductors, carbon materials, or conductive polymers prepared by the electrospinning process have exhibited inspiring properties, including a large specific surface area, porous structure, and nice stability, with bright application prospects in advanced gas sensors. Meanwhile, the increasingly expanding applications of gas sensors, such as the Internet of Things (IoT), the food industry, disease diagnosis, etc., have raised higher sensor performance requirements. To further enhance the gas-sensing performance of nanofibers, the scheme of functionalized nanofiber strategies, either in electrospinning or post-treatment, has been proposed and verified. This review systematically summarized the nanostructures, gas-sensing properties, and functional mechanisms of modified nanofibers. Additionally, the perspectives and challenges regarding electrospun nanofibers for gas sensing were discussed. Full article

Humidity and oxygen have significant impacts on the accuracy of hydrogen detection, especially for metal oxide semiconductor sensors at room temperature. Addressing this challenge, this study employs a screen-printed 1 × 2 resistive sensor array made from an identical 1 wt.% platinum-modified tin oxide nanoparticle material. Fabrication variability between the two sensing elements was intentionally leveraged to enhance array output differentiation and information content. Systematic hydrogen-sensing tests were conducted on the array under diverse oxygen and moisture conditions. Three distinct feature types—the steady-state value, resistance change, and area under the curve—were extracted from the output of each array element. These features, integrated with their quotient, formed a nine-feature vector matrix. A multiple linear regression model based on this array output was developed and validated for hydrogen prediction, achieving a coefficient of determination of 0.95, a mean absolute error of 125 ppm, and a mean relative standard deviation of 7.07%. The combined information of the array provided significantly more stable and precise hydrogen concentration predictions than linear or nonlinear models based on individual sensor features. This approach offers a promising path for mass-producing highly interference-resistant, precise, and stable room-temperature hydrogen sensor arrays. Full article