Microelectromechanical Systems Research Articles

Some novel exact solutions for the generalized time-space fractional coupled Hirota-Satsuma KdV equation

In this paper, two efficient methods, namely the modified G′/G,1/G-expansion method and the G′/bG′+G+a-expansion method, are employed to obtain novel exact wave solutions for the generalized time-space fractional coupled Hirota-Satsuma KdV equation. Various types of analytical explicit solutions, including well-known bell-shape solitons, mixed solitary wave solutions, and periodic wave solutions are obtained. These solutions are of great significance for revealing the nonlinear interaction between two long waves with different dispersion effects. The two-dimensional and three-dimensional distribution maps and contour plots corresponding to partial solutions are simulated to visually display the evolution process of relevant physical quantities over time. Moreover, the potential applications of these solutions in nano/micro devices and systems, especially in MEMS (Micro-Electro-Mechanical Systems) are discussed. It is demonstrated that the methods and processes utilized have strong applicability for constructing analytical solutions of nonlinear evolution equations.

Phase stable OCT with a 1050 nm tunable VCSEL and photonic integrated circuit

A turnkey phase-sensitive swept-source optical coherence tomography (OCT) system requires stabilization of both the swept source and main signal interferometer. We have provided stable clocking and triggering of a 1050 nm swept micro-electromechanical system (MEMS) vertical cavity surface emitting laser (VCSEL) by mounting a solid clock etalon and volume Bragg grating optical trigger inside a temperature-stabilized butterfly package. A photonic integrated circuit (PIC) provides a phase-stable main interferometer near the sample. This system is only sensitive to the motion of the sample, not to the fibers leading to and from the PIC. We provide optical frequency domain reflectivity measurements of the PIC performance. We also demonstrate OCT imaging as well as static and dynamic phase measurements of a Kindle e-book reader electrophoretic display.

Aerosol Deposited Polycrystalline PbZr0.53Ti0.47O3 Thick Films with a Large Transverse Piezoelectric Coefficient

The aerosol deposition (AD) method utilizes high kinetic-energy submicron powders to impact and form a film on a substrate. It is a highly efficient deposition method, capable of producing films or coatings with a strong interfacial bonding and a dense nano-grain structure without thermal assistance. In this work, PbZr0.53Ti0.47O3 (PZT53/47) films (~1.2 μm thick) were deposited on Pt/Ti/Si(100) substrates via the AD method. After a conventional annealing process (700 °C for 1 h), these PZT53/47 films displayed a dense, crack-free, nano-grained morphology, corresponding to an optimal electrical performance. A large maximum polarization (Pmax = 70 μC/cm2) and a small coercive field (Ec = 104 kV/cm) were achieved under the maximum applicable electric field of 1.6 MV/cm. The PZT53/47 films also exhibited a large small-field dielectric constant of ~984, a high tunability of 72%, and a low leakage current of ~3.1 × 10−5 A/cm2 @ 40 V. Moreover, the transverse piezoelectric coefficient (e31.f) of these AD-processed films was as high as −4.6 C/m2, comparable to those of sputter-deposited PZT53/47 films. These high-quality PZT53/47 thick films have broad applications in piezoelectric micro-electromechanical systems.

Early Diagnosis of Pneumonia and Chronic Obstructive Pulmonary Disease with a Smart Stethoscope with Cloud Server-Embedded Machine Learning in the Post-COVID-19 Era

Background/Objectives: Respiratory diseases are common and result in high mortality, especially in the elderly, with pneumonia and chronic obstructive pulmonary disease (COPD). Auscultation of lung sounds using a stethoscope is a crucial method for diagnosis, but it may require specialized training and the involvement of pulmonologists. This study aims to assist medical professionals who are non-pulmonologist doctors in early screening for pneumonia and COPD by developing a smart stethoscope with cloud server-embedded machine learning to diagnose lung sounds. Methods: The smart stethoscope was developed using a Micro-Electro-Mechanical system (MEMS) microphone to record lung sounds in the mobile application and then send them wirelessly to a cloud server for real-time machine learning classification. Results: The model of the smart stethoscope classifies lung sounds into four categories: normal, pneumonia, COPD, and other respiratory diseases. It achieved an accuracy of 89%, a sensitivity of 89.75%, and a specificity of 95%. In addition, testing with healthy volunteers yielded an accuracy of 80% in distinguishing normal and diseased lungs. Moreover, the performance comparison between the smart stethoscope and two commercial auscultation stethoscopes showed comparable sound quality and loudness results. Conclusions: The smart stethoscope holds great promise for improving healthcare delivery in the post-COVID-19 era, offering the probability of the most likely respiratory conditions for early diagnosis of pneumonia, COPD, and other respiratory diseases. Its user-friendly design and machine learning capabilities provide a valuable resource for non-pulmonologist doctors by delivering timely, evidence-based diagnoses, aiding treatment decisions, and paving the way for more accessible respiratory care.

Direct observations of nucleation and early-stage growth of Au-catalyzed GaAs nanowires on Si(111)

Developing a reliable procedure for the growth of III-V nanowires (NW) on silicon (Si) substrates remains a significant challenge, as current methods rely on trial-and-error approaches with varying interpretations of critical process steps such as sample preparation, Au-Si alloy formation in the growth reactor, and NW alignment. Addressing these challenges is essential for enabling high-performance electronic and optoelectronic devices that combine the superior properties of III-V NW semiconductors with the well-established Si-based technology. Combining conventional scalable growth methods, such as metalorganic chemical vapor deposition (MOCVD) within situcharacterization using environmental transmission electron microscopy (ETEM-MOCVD) enables a deeper understanding of the growth dynamics, if that knowledge is transferable to the scalable processes. We report on successful epitaxial growth of Au-catalyzed GaAs NWs on Si(111) substrates using micro-electromechanical system chips with monocrystalline Si-cantilevers in both conventional MOCVD and ETEM-MOCVD systems. The conventional MOCVD provided a framework for initial parameter tuning, while ETEM-MOCVD offered valuable insights into early nucleation and catalyst-substrate interactions. Our findings show that nucleation is significantly influenced by the removal of native oxide layers and the initial formation of the Au-Si alloy. Ourin situstudies revealed different NW-substrate interfaces, essential for optimizing the epitaxial growth process. We identified three typical configurations of NW 'roots', each impacted by growth conditions and preparation steps, affecting the structural and potentially the optical properties of the NWs. Similarly, doping from the Si-substrate may affect both optical and electrical properties; however, compositional analysis revealed no traces of Si in NWs post-nucleation and a small amount in the catalytic droplet. Our research highlights the importance ofin situstudies for a comprehensive understanding of nucleation mechanisms, paving the way for optimizing III-V NW growth on Si substrates and developing high-performance III-V/Si devices.

A multi-physical coupling NURBS-based isogeometric analysis for nonlinear electrodynamics of three-directional poroelastic functionally graded circular nanoplate: Introducing deep neural network algorithm for nonlinear electrodynamics problems

For the right design of nanosystems with integrated piezoelectric transducers and materials, it is crucial to understand the electro-mechanical coupling factor. Considering this, this work determines the influence of placement and dimension of piezoelectric patch on the vibrations of circular sandwich sector nanoplate coupled with an electrically layer. The core of the current nanostructure is made of three-directional poroelastic functionally graded material (3D-PFGM). The quasi-3D sinusoidal shear deformation theory (Q-3DSSDT) considering the effect of thickness stretching, compatibility conditions, and Hamilton's principle are coupled with each other regarding discovering the general motion equations and boundary domains related to the circular sector sandwich nanoplate. For considering the size effect, nonlocal quasi-3D sinusoidal strain gradient theory (NQSSGT) by employing both hardening and softening effects is considered. The NURBS-based isogeometric analysis is applied to answer the partial differential coupled equations (PDCE). In addition, the finite element method is implemented for more verification and presenting important outcomes. The novelties of this work are considering the effects of NQSSGT, placement, and dimension of the piezoelectric patch in addition to considering 3D-PFGM of the circular sector sandwich nanoplate. After obtaining the datasets of the mathematics simulation, a deep neural network algorithm is presented to test, train, and validate the presented nonlinear electrodynamics response of the current circular sector sandwich nanoplate. The results of the current nanostructure can be used in related industries of nano-robots and nano-electronic devices for future works. The findings highlight the significant influence of material gradation, poroelastic effects, and piezoelectric coupling on the vibration characteristics, offering valuable insights for the design and optimization of smart materials and structures in microelectromechanical systems (MEMS), sensors, and actuators. This research paves the way for future innovations in the field of advanced functional materials and their applications in high-precision technologies.

Reduction of nonlinear distortion in condenser microphones using a simple post-processing technique.

In this paper, an approach for effectively reducing nonlinear distortion in single-backplate condenser microphones is introduced, i.e., most microelectromechanical systems (MEMS) microphones, studio recording condenser microphones, and laboratory measurement microphones. This simple post-processing technique can be easily integrated on external hardware such as an analog circuit, microcontroller, audio codec, digital signal processing unit, or within the Application Specific Integrated Circuit chip in a case of MEMS microphones. It effectively reduces microphone distortion across its frequency and dynamic range, and relies on a single parameter, which can be derived from either the microphone's physical parameters or a straightforward measurement presented in this paper. An optimal estimate of this parameter achieves the best distortion reduction, whereas overestimating it never increases distortion beyond the original level. The technique was tested on a MEMS microphone. The findings indicate that for harmonic excitation, the proposed technique reduces the second harmonic by approximately 40 dB, leading to an effective reduction in the total harmonic distortion. The efficiency of the distortion reduction technique for more complex signals is demonstrated through two-tone and multitone experiments, where second-order intermodulation products are reduced by at least 20 dB.

Nonlocal effects on curved double-walled carbon nanotubes based on nonlocal theory

Curved double-walled carbon nanotubes (CDWCNTs) are crucial components in nanoelectronics, mechanical sensors, and composite materials due to their unique geometry and structural properties. Electron microscopy images have revealed that carbon nanotubes are rarely perfectly straight, often exhibiting curvature or waviness along their length due to inherent geometrical imperfections. The accurate mechanical modeling of these structures is essential, particularly to capture size-dependent effects that classical elasticity theories fail to account for. In this study, a novel analytical framework was introduced for combining the initial value method with the approximate transfer matrix approach to analyze the mechanical behavior of CDWCNTs under anti-plane loading within the framework of nonlocal elasticity theory. The proposed methodology provides an effective and computationally efficient alternative to traditional analytical approaches. By analyzing displacements, rotations, bending moments, and shear forces, substantial deviations were revealed between classical and nonlocal elasticity solutions, particularly as the dimensionless nonlocal parameter R/γ decreased. The results show that nonlocal effects become dominant at smaller size parameters, especially in displacements, rotations, and bending moments, while shear forces remain unaffected. These findings emphasize the critical role of nonlocal effects in accurately predicting nanoscale mechanical responses and offer valuable insights for modeling advanced nanostructures in emerging technologies, such as microelectromechanical systems and nanotechnology. Convergence studies have confirmed the accuracy and stability of the proposed approach, thereby establishing this as a robust tool for modeling nanoscale structures.

Selective Undercut of Undoped Optical Membranes for Spin-Active Color Centers in 4H- Silicon Carbide.

Silicon carbide (SiC) is a semiconductor used in quantum information processing, microelectromechanical systems, photonics, power electronics, and harsh environment sensors. However, its high-temperature stability, high breakdown voltage, wide bandgap, and high mechanical strength are accompanied by a chemical inertness, which makes complex micromachining difficult. Photoelectrochemical (PEC) etching is a simple, rapid means of wet processing SiC, including the use of dopant-selective etch stops that take advantage of the mature SiC homoepitaxy. However, dopant-selective PEC etching typically relies on highly doped material, which poses challenges for device applications such as quantum defects and photonics that benefit from low doping to produce robust emitter properties and high optical transparency. In this work, we develop a selective PEC process that relies not on high doping but on the electrical depletion of a fabricated diode structure, allowing the selective etching of an n-doped substrate wafer versus an undoped epitaxial (carrier density of 1(10)14 cm-3) device layer. We characterize the photoresponse and PEC behavior of the diode under bias and use those insights to suspend large (100 × 100 μm) undoped membranes of SiC. We further characterize the compatibility of membranes with quantum emitters, performing comparative spin spectroscopy between undoped and highly doped membrane structures, finding the use of undoped material improves ensemble spin lifetime by >5×. This work enables the fabrication of high-purity suspended thin films suitable for scalable photonics, mechanics, and quantum technologies in SiC.

PERBANDINGAN HASIL PENGUKURAN GETARAN MENGGUNAKAN ACCELEROMETER TYPE PIOZOELECTRIC CRYSTAL (PCB) DENGAN TYPE MICRO ELECTRO MECHANICAL SYSTEM (MEMS)

The periodic vibration parameters are deviation, velocity, and acceleration, and the measuring instruments for the three parameters are called displacement pickups, velocity pickups, and accelerometers respectively. Recently, many other materials have been discovered for measuring vibrations called MEMS (Micro Electro Mechanical System) which provide an output in the form of a voltage so that it does not require an amplifier/charge amplifier. This MEMS technology accelerometer will replace the piezoelectric crystal (PCB) technology accelerometer. This research aims to determine the comparison of vibration measurement results from the two types of accelerometers. Both types of accelerometers are placed at the end of a metal plate which is clamped at the other end. The iron plate is vibrated by providing an impact and the vibration response is recorded by Dewesoft, the vibration response is also recorded in ambient conditions. From the results of vibration measurements in ambient conditions and given impact forces, these two types of accelerometers produce the same natural frequency values, while the amplitude values ??in the form of acceleration values ??have a difference of 4.75% for impact forces and 11.35% for ambient conditions.

Crystal structure of submicron-sized sulfur particles using 3D ED obtained in atmospheric conditions.

Lithium-sulfur batteries are a promising candidate for the next generation of rechargeable batteries. Despite extensive research on this system over the last decade, a complete understanding of the phase transformations has remained elusive. Conventional in-situ powder X-ray diffraction has struggled to determine the unit cell and space group of the polysulfides formed during charge and discharge cycles due to the high solubility of these solid products in the liquid electrolyte. With the improvement in in-situ electrochemical set-ups dedicated to transmission electron microscopes, three-dimensional electron diffraction (3D ED) has the potential to capture the crystal structures of the polysulfides during cycling. In this work, the structure solution and refinement from 3D ED data of elemental sulfur, known to sublimate in the vacuum of transmission electron microscopes, is enabled through the use of an environmental cell with a micro-electromechanical system. This work represents the first step in characterizing sulfur's transformation into lithium polysulfides using in-situ 3D ED.

Quality Factor Enhancement of Piezoelectric MEMS Resonators Based on Cross-Hole Fractal Phononic Crystals

In this paper, a cross-hole fractal phononic crystal (CHF-PnC) structure is proposed, which consists of vertical cross-holes repeating their original shapes in a certain ratio. Using the finite element method, the complex energy band curves and frequency responses of the CHF-PnC are calculated, and three complete bandgaps with strong attenuation characteristics are obtained, with bandwidths of 193.4, 55.7 and 216.8[Formula: see text]MHz, respectively. The mechanism of the generation of the bandgap of the CHF-PnC structure is analyzed, and the sensitivities of the geometrical parameters W and [Formula: see text] to the band gap are investigated. Subsequently, applying this structure to piezoelectric microelectromechanical systems (MEMS) resonators, it is found that the anchor point loss quality factor (Q[Formula: see text]) of the CHF-PnC resonator is 116,951.5% higher than the conventional resonator when a 6-row × 5-column combination is used. In addition, compared to the conventional resonator, the CHF-PnC resonator has a 69.7% reduction in insertion loss and a 3.6-fold improvement in unloaded quality factor, while maintaining the same electromechanical coupling coefficient.

Research on the integration of MEMS and reliable transmission of deep space networks based on time-sensitive networking

With the continuous deepening of human space exploration, deep space networks far away from Earth have emerged. Unlike traditional ground networks, they have the characteristics of frequent link interruptions and time extensions. Traditional data transmission mechanisms cannot be well applied in deep space networks. We propose a data transmission technology that integrates time-sensitive networking and artificial intelligence to address the contradiction between deterministic delay and differentiated service quality assurance in deep space networks and construct a micro electromechanical system (MEMS). Considering the differences in service quality due to different business requirements, data transmission in deep space networks is transformed into a mixed integer programming problem that minimizes transmission delay and maximizes link utilization and solved using artificial intelligence imitation learning. Experimental results have shown that the proposed algorithm has fast convergence, strong applicability, and can achieve reliable and efficient data transmission while meeting the requirements of higher priority data transmission. It can also significantly improve throughput.

Near-Infrared Spectral MEMS Gas Sensor for Multi-Component Food Gas Detection

The complex application environments of gas detection, such as in industrial process monitoring and control, atmospheric and environmental monitoring, and food safety, require real-time and online high-sensitivity gas detection, as well as the accurate identification and quantitative analysis of gas samples. Despite the progress in gas analysis and detection methods, high-precision and high-sensitivity detection requirements for target gases of multiple components in mixed gases are still challenging. Here, we demonstrate a micro-electromechanical system (MEMS) with near-infrared (NIR) spectral gas detection technology and spectral model training, which is used to improve the detection and classification of multi-component gases in food. During blind sample testing, the NIR spectral gas sensor demonstrated over 90% accuracy in identifying mixed gases, as well as achieving the classification of ethanol concentration. We envision that our design strategy of an NIR spectral gas sensor could enhance the gas detection and distinguishing ability under the conditions of background gas interference and cross-interference in multi-component detection.

Enhancement of Synchronization in Nonlinear MEMS Oscillator Based on Electrothermal Adjustment

Abstract Synchronization in Microelectromechanical Systems (MEMS) typically encounters the impact of electrothermal phenomena, often in conjunction with piezoresistive detection or frequency tuning. However, the effects of electrothermal on synchronization have not been previously explored. This paper investigates the electrothermal effects on synchronization bandwidth and frequency stability in a nonlinear MEMS arch oscillator. Experimental results demonstrate a non-monotonic pattern in synchronization bandwidth as electrothermal current increases, corroborated by theoretical models based on quality factors and equivalent nonlinearity. Drawing from theoretical analysis, which suggests that synchronization can be enhanced by adjusting feedback and perturbation strength, we achieved a 5.72-fold enhancement in synchronization bandwidth in our experiments. Furthermore, we observed that increased electrothermal significantly improve frequency stability. We developed a model based on the Allan deviation that incorporates electrothermal temperature to evaluate frequency stability, and this model successfully verified our experimental results. These experimental and theoretical findings highlight the potential of electrothermal effects to enhance synchronization and frequency stability in MEMS devices, paving the way for more robust sensor technology applications.

Data-Driven Performance Evaluation of Machine Learning for Velocity Estimation Based on Scan Artifacts from LiDAR Sensors

<div>Light detection and ranging (LiDAR) sensors are increasingly applied to automated driving vehicles. Microelectromechanical systems are an established technology for making LiDAR sensors cost-effective and mechanically robust for automotive applications. These sensors scan their environment using a pulsed laser to record a point cloud. The scanning process leads in the point cloud to a distortion of objects with a relative velocity to the sensor. The consecutive generation and processing of points offers the opportunity to enrich the measured object data from the LiDAR sensors with velocity information by extracting information with the help of machine learning, without the need for object tracking. Turning it into a so-called 4D-LiDAR. This allows object detection, object tracking, and sensor data fusion based on LiDAR sensor data to be optimized. Moreover, this affects all overlying levels of autonomous driving functions or advanced driver assistance systems. However, since such sensor-specific effects are rarely available in public datasets and the velocities of target objects are not included as ground truth in these datasets, it makes sense to enrich the limited real-world data with synthetic data. Therefore, this article discusses how such datasets can be created and combined to efficiently estimate velocities on real-world data using the novel method named VeloPoints.</div>

Advancements in MEMS Micromirror and Microshutter Arrays for Light Transmission Through a Substrate.

This paper reviews and compares electrostatically actuated MEMS (micro-electro-mechanical system) arrays for light modulation and light steering in which transmission through the substrate is required. A comprehensive comparison of the technical achievements of micromirror arrays and microshutter arrays is provided. The main focus of this paper is MEMS micromirror arrays for smart glass in building windows and façades. This technology utilizes millions of miniaturized and actuatable micromirrors on transparent substrates, enabling use with transmissive substrates such as smart windows for personalized daylight steering, energy saving, and heat management in buildings. For the first time, subfield-addressable MEMS micromirror arrays with an area of nearly 1 m2 are presented. The recent advancements in MEMS smart glass technology for daylight steering are discussed, focusing on aspects like the switching speed, scalability, transmission, lifetime study, and reliability of micromirror arrays. Finally, simulations demonstrating the potential yearly energy savings for investments in MEMS smart glazing are presented, including a comparison to traditional automated external blind systems in a model office room with definite user interactions throughout the year. Additionally, this platform technology with planarized MEMS elements can be used for laser safety goggles to shield pilots, tram, and bus drivers as well as security personal from laser threats, and is also presented in this paper.

The Application Potential of Microelectronic Processing and Integrated Circuit in Mechanical Design

The rapid development of microelectronic processing has not only fostered its interdisciplinary fusion with mechanical design. With the introduction of microelectronic processing, the precise control capabilities of mechanical systems have been significantly bolstered, and the energy consumption of machinery and equipment was also optimized, which has led to an increasingly high degree of automation, allowing for the execution of complex tasks and autonomous decision-making. Additionally, as both technologies continue to evolve towards smaller scales, their application scope is expanding, including Micro Electro Mechanical System (MEMS), sensors, etc. This paper explores the application of microelectronic processing and integrated circuits in mechanical design, elucidating how advancements in microelectronics enhance the automation and intelligence of mechanical equipment. Furthermore, with the rise of nanotechnology, the paper discusses new applications of microelectronic processing in mechanical design fields such as automation control systems, sensors, and embedded systems. Meanwhile, the cost reduction and standardization of integrated circuits have boosted their popularity in a wider range of fields

Investigation of Crack Effects on the Nonlinear Vibrations of Microbeams with a Tip Mass in a Magnetic Field

Microelectromechanical systems (MEMS) are critical members of modern technological devices, due to their applications in various industrial fields. In the physical applications of MEMS, cracks are a common structural problem, affecting the static and dynamic behavior of the system. In this paper, the effects of cracks on microbeams with a tip mass under the influence of a magnetic field have been investigated. The micro-size effect of the beam has been involved into the model by using the modified couple stress theory. The crack has been modeled by using a torsional spring, with the spring coefficient corresponds to the severity of the crack. Thus, the beam has been modeled as consisting of two segments connected by a torsional spring. The equations of motion have been formulated using Hamilton’s principle. The obtained equations have been solved by using the method of multiple scales, a perturbation technique. Frequencies regarding both linear and nonlinear vibrations of the microbeams have been examined. The results obtained in this study have been validated by using available numerical results in the literature. The effects of parameters such as crack severity, crack location, tip mass and the magnetic field force on linear and nonlinear vibrations have been presented. The results indicate a significant decrease in the natural frequencies and nonlinear frequencies of microbeams with increasing crack severity.

Application of MEMS technology in anti-electromagnetic radiation maternity clothes: state of the art and future perspectives

This review provides a comprehensive analysis of the application of Micro-Electro-Mechanical Systems (MEMS) technology in anti-electromagnetic radiation maternity wear. The review commences with an elaboration of the electromagnetic shielding principles of traditional materials and the principle of anti-electromagnetic radiation. Subsequently, the role of MEMS in maternity clothing is detailed, including the real-time monitoring of radiation via sensors, the enhancement of fabric shielding through electrospinning and material deposition, and the realization of intelligent functions such as micro-actuators and communication modules. Furthermore, the review considers the optimization of performance, taking into account factors such as electromagnetic shielding, air permeability and comfort. Furthermore, the article addresses the challenges of ensuring comfort and power supply. The article concludes by emphasizing the potential of MEMS in protecting pregnant women and fetuses and proposes future research directions, including an in-depth exploration of the working principles, technical specifications, and performance characteristics of key MEMS components (sensors and micro-actuators), as well as research on the combination and The combination of MEMS technology with existing anti-radiation technologies, such as traditional metal fiber fabrics and nanomaterials, has the potential to yield significant synergistic effects. Furthermore, an in-depth analysis of performance optimization, including durability and washing stability of maternity clothes, is essential. Additionally, the exploration of emerging technologies, such as bubble electrospinning in maternity clothes, could lead to innovative applications in this field.