MXene Functionalized,Highly Breathable and Sensitive Pressure Sensors with Multi-Layered Porous Structure

Breathable, flexible, and highly sensitive pressure sensors have drawn increasing attention due to their potential in wearable electronics for body-motion monitoring, human-machine interfaces, etc. However, current pressure sensors are usually assembled with polymer substrates or encapsulation layers, thus causing discomfort during wearing (i.e., low air/vapor permeability, mechanical mismatch) and restricting their applications. A breathable and flexible pressure sensor is reported with nonwoven fabrics as both the electrode (printed with MXene interdigitated electrode) and sensing (coated with MXene/silver nanowires) layers via a scalable screen-printing approach. Benefiting from the multi-layered porous structure, the sensor demonstrates good air permeability with high sensitivity (770.86–1434.89 kPa⁻¹), a wide sensing range (0–100 kPa), fast response/recovery time (70/81 ms), and low detection limit (≈1 Pa). Particularly, this sensor can detect full-scale human motion (i.e., small-scale pulse beating and large-scale walking/running) with high sensitivity, excellent cycling stability, and puncture resistance. Additionally, the sensing layer of the pressure sensor also displays superior sensitivity to humidity changes, which is verified by successfully monitoring human breathing and spoken words while wearing a sensor-embedded mask. Given the outstanding features, this breathable sensor shows promise in the wearable electronic field for body health monitoring, sports activity detection, and disease diagnosis.     

Frequency Selectivity via Inner Boundary Conditions for A Self-Powered Multiresonant Acoustic Sensing Array with Broad Bandwidth

This study investigates and proposes innovative approaches to achieve frequency selectivity within a limited space. Traditional multiresonant acoustic devices use individual sensing elements of varying sizes to achieve resonance frequency (f_r), leading to an inability to sense focused acoustic waves, unlike the human ear. A miniaturized, self-powered artificial basilar membrane that incorporates multiresonant features is introduced. Multiple f_r of the diaphragms are developed using inner boundary conditions (iBCs) defined by an adjustable micropatterned elastomeric support (µ-support) and a porous nanofiber (NF) mat. This new approach offers the advantage of all-in-one fabrication, eliminating the need for device area variation or an additional rigid frame typically required in conventional multiresonant acoustic devices. The efficacy of the iBCs in shifting f_r within the vocal frequency ranges is verified via a laser Doppler vibrometer, simulation, and triboelectric output. With its self-powering capabilities based on triboelectric principles, this artificial basilar membrane holds promise for accurately recognizing musical and vocal signals with specific frequency characteristics. With four different iBCs in a total device area of 23 × 23 mm², a tunable four-channel system with f_r ranging from 400 to 3000 Hz is achieved. This advancement enables the sensing of focused acoustic waves, simulating the functionality of an artificial human ear model.     

微热板式低气压传感器的研制

研制了一种采用CMOS工艺和表面牺牲层技术加工的微热板式低气压传感器．该微热板为四臂支撑悬空矩形板，其边长为75μm，支撑桥长为60μm，板下气隙高度为0.5μm．采用经典傅里叶传热理论分析了恒电流工作方式下气压对微热板瞬态和稳态热特性的影响，结果表明在低气压范围内微热板传热以支撑桥导热为主，气压较高时以气体导热为主，微热板加热功率随气压增加而减小；传感器的热响应时间为毫秒量级并随气压增加而减小．传感器采用恒电流工作方式时，测得其气压响应范围为1～10~5Pa，且加热功率与气压间关系的理论分析结果与实测值吻合得较好．     

压力传感器芯片键合用低温玻璃焊料的研制

研制开发了一种用于压力传感器芯片与 1 0 1玻璃基座相封接的三元系结晶性低温玻璃焊料 ,其基本成份为 Pb O:Zn O:B2 O3 =58:1 8:2 4 (% wt)。已用 DSC分析该玻璃焊料 ,显示在 51 0℃出现主晶相的熔化吸热峰 ,其开始熔化温度为 445℃。在硅芯片背面制备一过渡层 ,然后用此低温玻璃焊料将压力传感器芯片与玻璃基座封接在一起。封接温度为 530℃ ,低于铝硅合金相的低共熔温度 577℃。用这一封接技术制备的压力传感器有良好的技术性能 ,热漂移小且能耐沸水、耐油 ,耐 1 50℃热冲击。封接强度达 7MPa。     

A Continuous Pressure Positioning Sensor with Flexible Multilayer Structures Based on a Combinatorial Bionic Strategy

A high-performance flexible pressure sensor is one of the most important components of electronic skin, which can endow artificial devices with human-like capabilities. However, the electronic skin usually relies on the arrays of sensors to simultaneously obtain both pressure magnitude and position, making the data processing time-consuming, tedious, and error-prone. Here, a novel continuous pressure positioning sensor (PPS) with flexible multilayer structures based on a combinatorial bionic strategy is designed and fabricated. This PPS is composed of the pressure sensing layer (PSL) and the pressure positioning layer (PPL). The PSL exhibits high sensitivity (18.87 kPa⁻¹) owing to the bionic crack structures. Based on the connection/disconnection of the upper and lower conductive layers, this PPL exhibits excellent positioning properties with excellent resolution (≈35 µm). More importantly, due to stable signal change and synchronization of signals between the two functional layers (>21 pa), this PPS can recognize the type of signal. Applications of the PPS for pressure monitoring, tire safety monitoring, lunar rover road condition monitoring, and emotional communication in human–computer interaction are further demonstrated to measure magnitude, position, and recognition of pressure signals. So, it will have broad application prospects in fields such as pressure detection and human–computer interaction.     

自聚焦共焦光纤传感系统的相干传递函数

在弱物体近似下，运用傅立叶光学，从成像系统角度对自聚焦共焦传感技术进行了理论研究。首重分析了该技术测量样品纵深结构时图像的成像机理。由于光纤具有本征场的模式，对光的振幅和相位的响应是相干的，从而可用相干传递函数（CTF）描述系统性能。结果表明，系统相当于一复振幅线平移不变系统，具有低通特性和层析特性。