Micromachines最新文献

The whole-angle hemispherical resonator gyroscope (WA-HRG) is critical to high-precision attitude control and navigational positioning, boasting significant deployment potential in both highly dynamic inertial navigation systems and industrial instrumentation. This paper presents a mechanistic analysis of quantization error inherent to the HRG's hardware detection and driving circuits, focusing specifically on its impact on parameter calculation and driving control in whole-angle mode. Furthermore, a simulation platform was constructed to verify and elucidate the correlations between the effects of quantization error and key resonator parameters, such as the major axis amplitude and the standing wave azimuth. Compared to existing HRG error studies which frame quantization error as isolated circuit noise, this work uniquely uncovers the azimuth-modulated periodic behavior of quantization error within the WA-HRG. It also formalizes a quantitative relationship between quantization error and the resonator's key parameters, laying a critical theoretical foundation for suppressing quantization error and enhancing accuracy in high-performance WA-HRGs.

As more and more Internet of Things (IoT) devices are widely deployed, the issue of energy supply for these devices is becoming increasingly prominent. Considering not only the wireless information transfer (WIT) function of traditional IoT networks but also the characteristics of wireless power transfer (WPT), an RF energy harvesting-aided IoT network is proposed in this paper. In the new IoT network, a WPT transmitter and a WPT receiver are, respectively, introduced to the new gateway and the new end-device. A WPT transmitter is mainly composed of an antenna selection circuit, a power amplifier, and a directional antenna. A WPT receiver consists of a directional antenna, a matching network, a rectification circuit, and an energy management circuit. In order to coordinate WPT and WIT in an orderly manner and minimize WPT's interference on WIT, a time-division scheme is adopted. The proposed new IoT network aims to offer a new IoT scheme combining both WIT and WPT technologies. In addition, IoT devices can obtain a new energy supply through RF energy harvesting. Both the effectiveness and efficiency of the proposed RF energy harvesting-aided IoT network have been validated through experimentation.

Hollow microneedle arrays of different shapes were prepared for blood collection and precise drug delivery. This microneedle array was investigated using shape modification and hole position optimization, and different approaches to increase the strength of the microneedles and hole alignment were analyzed. Firstly, solid-tip microneedles were prepared using deep X-ray lithography, and an approach to increase the strength of microneedles by modifying the shape of the photomask was examined. Secondly, photomasks with holes in different positions were designed, and the exposure was aligned at different hole positions. Finally, the maximum stress and minimum displacement were analyzed using ANSYS 10.0 simulation software, while the proof-of-strength properties were accomplished by inserting microneedles into a polyimide film. The experimental results show that the modification of the shape of the photomask can increase the strength of the microneedles and compensate for the shortcomings generated by the moving exposure. Placing the holes away from the center of the tip can increase the flow rate of the microneedles. A horizontal offset of 30 μm and a vertical offset of 50 μm from the center of the microneedle tip were determined to be the best positions for aligning the holes. This meets the requirements for microneedle strength and sharpness.

Module-level free-space optical interconnects require actuators to combine both large stroke and high stability. To address this core trade-off that plagues traditional folded-beam actuators, we have developed a millimeter-scale MEMS electromagnetic actuator integrating a Differential Motion Rejection (DMR) unit with a rigid frame. Its performance was systematically evaluated through magnetic-structural coupling modeling, finite element simulation, and experiments. The actuator achieved millimeter-scale stroke under sinusoidal drive, with a primary resonant frequency of approximately 31 Hz. The introduction of the DMR and frame proved highly effective: the out-of-plane displacement at resonance was reduced by about 97%, the static Z-direction stiffness increased by over 50 times, and the displacement crosstalk decreased to 0.265%. Optical testing yielded a stable deflection angle of approximately ±21°. These results demonstrate that this design successfully combines large stroke with high stability, significantly suppressing out-of-plane parasitic motion and crosstalk, making it suitable for module-level optical interconnect systems with stringent space and stability requirements.

Pressure pipelines are widely used in the energy and transportation fields for conveying natural gas, water, etc. Under complex and harsh conditions with long-term operation, this easily leads to leakage, threatening the safe and stable operation of transportation systems. Although acoustic sensors support non-destructive leakage detection, their accuracy is restricted by noise interference and minor leakage uncertainties, and existing systems lack a targeted integration design for pipeline scenarios. To address this, the micro-electromechanical system (MEMS) is specifically designed as an MEMS microphone array integrated system (MEMS-MAIS), which is applied for pipeline leakage detection through data fusion at different levels. First, a dedicated MEMS microphone array system is designed to realize high-sensitivity collection of leakage acoustic data. In addition, the integrated feature extraction and feature-level fusion modules are proposed to retain effective information, and a decision-level fusion module is incorporated to improve the reliability of leakage detection results. To verify the designed system, an experiential platform is established with several microphone data. The results indicate that the proposed MEMS-MAIS exhibits excellent anti-interference performance and leakage detection accuracy of 94.67%. It provides a reliable integrated system solution for pipeline leakage detection and verifying high engineering application value.

High-resolution three-dimensional temperature fields are essential for studying flame combustion, and tunable diode laser absorption tomography (TDLAT) is an effective method for diagnosing flame combustion conditions. In actual combustion measurements, the reliance of TDLAT on line-of-sight (LOS) measurements leads to limited data and reduced dimensionality in analyzing combustion fields. This study proposes a method using area-array sensor-coupled absorption spectroscopy to measure the three-dimensional temperature field of flame accurately, aiming for enhanced combustion diagnosis. The laser beam is configured into a cone shape, and after traversing the combustion field under examination, the area-array sensor receives a projection signal. This signal is then used to reconstruct a high-resolution, multidimensional temperature field. We confirmed the accuracy and robustness of the algorithm through numerical simulations and compared these with experimental results from the TDLAT setup. Our TDLAT detection system demonstrates high precision and effectively measures temperature fields in complex flame imaging scenarios.

Thermoelectric generators (TEGs) based on single-walled carbon nanotubes (SWCNTs) offer a promising approach for powering sensors in wearable systems. However, achieving high performance remains challenging because the high thermal conductivity of SWCNTs limits the temperature gradient within the device. We previously developed flexible SWCNT-TEGs with enhanced heat dissipation by dip-coating SWCNTs onto mesh sheets; however, their performance in real wearable environments had not been evaluated. In this study, we demonstrate the practical operation of these SWCNT-TEGs under conditions such as fingertip contact and cap-based wear. The output voltage increased proportionally with the number of fingers touching the device, and a stable voltage of 6.1 mV was obtained when the TEG was mounted on a cap and worn outdoors at 7 °C. These findings highlight the promising potential of flexible SWCNT-TEGs as power sources for next-generation wearable technologies, including human-computer interaction and health monitoring.

In this paper, composite structures were fabricated by incorporating silver nanowires (AgNWs) with various metal oxides via the sol-gel method. This approach enhanced the electrical performance of AgNW-based transparent electrodes while simultaneously improving their stability under damp heat conditions and modifying the local medium environment surrounding the AgNW meshes. The randomly distributed AgNW meshes fabricated via drop-coating were treated with plasma to remove surface organic residues and reduce the inter-nanowire contact resistance. Subsequently, a zinc oxide (ZnO) coating was applied to further decrease the sheet resistance (R_sheet) value. The pristine AgNW mesh exhibits an R_sheet of 17.4 ohm/sq and an optical transmittance of 93.06% at a wavelength of 550 nm. After treatment, the composite structure achieves a reduced R_sheet of 8.7 ohm/sq while maintaining a high optical transmittance of 92.20%. The use of AgNW meshes as window electrodes enhances electron injection efficiency and facilitates the coupling mechanism between localized surface plasmon resonances and excitons. Compared with conventional ITO transparent electrodes, the incorporation of the AgNW mesh leads to a 17-fold enhancement in ZnO emission intensity under identical injection current conditions. Moreover, the unique scattering characteristics of the AgNW and metal oxide composite structure effectively reduce photon reflection at the device interface, thereby broadening the angular distribution of emitted light in electroluminescent devices.

Firstly, the five key development trends in the field of piezoelectric materials are discussed to offer the present perspective: "Performance to Reliability," "Hard to Soft," "Macro to Nano," "Homo to Hetero," and "Single to Multi-functional [...].

In order to explore the effect of stress on the damage of 4H-SiC materials, this paper employed single abrasive grain indentation simulation based on the Smoothed-Particle Hydrodynamics (SPH) method, and verified the accuracy of the indentation model through an indentation experiment on a single abrasive grain. The research examined the consequences of varying pressures on the processing of 4H-SiC, including parameters such as the depth of abrasive grain penetration, the stress-affected region, and the initiation and propagation of cracks. Subsequently, mathematical models were developed to characterize stress variations under different pressure conditions. The findings reveal several vital insights: First, a discernible linear relationship exists between the depth of abrasive grain penetration into 4H-SiC and the applied pressure. Second, within a specific pressure range, the stress-affected zone within the workpiece enlarges as the applied pressure increases. However, when cracks form within the workpiece, the dimensions of the stress-affected zone exhibit fluctuations. During the abrasive grain indentation phase, a discernible pattern emerges in the stress distribution within the workpiece.