An absolute MEMS capacitance vacuum sensor with a full range of (1-1000) Pa has been designed, fabricated and tested. The working principle of the capacitance vacuum sensor is explained and its fabrication process is introduced. For obtaining high sensitivity, the sensor's pressure-sensing diaphragm with large width-to-thickness ratio is manufactured using the silicon-on-insulator (SOI). A silicon buffer block is adopted to improve the linearity of the sensor and prevent the pressure-sensing diaphragm from being damaged due to overload. The sensor is packaged by anodic bonding process in a certain high vacuum environment to form a sealed cavity, in which the vacuum degree is maintained by the non-evaporable getter (NEG) film deposited on the buffer block surface. The absolute pressure measurement of the packaged sensor has been performed with a vacuum measurement system. The tests results show that the capacitance-pressure curve is piecewise linear in the full range (1-1000) Pa. And the sensor exhibits high stability and reproducibility. The maximum sensitivity of the sensor is 33.03 fF/Pa, while the resolution can reach 0.5 Pa. Moreover, the temperature characteristic of the sensor has been evaluated, and it turns out that the effect of temperature on the sensor is quite small in a certain temperature range. [2020-0276]
Dysphagia is common after a cerebral vascular accident (or stroke), and it seriously affects the prognosis. Timely diagnosis in clinical, scientific assessment of dysphagia and correct treatment given to patients are essential. This study is aimed to develop a sensor for measuring tongue pressure during swallowing or other times, and to help doctors make a scientific assessment of dysphagia grade. It is a kind of miniaturization of piezoresistive pressure sensor with an outer diameter of 10mm and a thickness of 3mm. A calibration and data acquisition ARM system is designed, which can continuously record tongue pressure in 8 hours. The sensor has a detection range from 0 to 30kPa, and the measurement error can be controlled in 5%.
Fourier transform spectrometers (FTS) based on piston-scanning MEMS mirrors have clear advantages of small size and low cost. However, the performance of this type of MEMS FTS is seriously limited by the difficulty of precisely controlling the tilt angle of the MEMS mirror plate during its piston scanning. This paper reports an integrated tilt angle sensing method, which is achieved via a mixed signal integrated optoelectronic position sensor (iOE-PS) that is bonded directly on the back of an electrothermally-actuated MEMS mirror. The iOE-PS integrates a laser diode, a band-gap reference, a quadrant photo-detector (QPDs), and the QPDs' readout circuits all on a single chip. The iOE-PS has been fabricated in a 180 nm CMOS process. Experimental results show that the iOE-PS has a linear response when the MEMS mirror plate moves vertically between 1.31 mm to 1.50 mm over the iOE-PS chip; the tilt angle can be measured up to at least 5° with a resolution of 0.0067°. The iOE-PS can greatly reduce the size and complexity of MEMS mirrors-enabled systems with integrated closed-loop control capability.
In order to solve the problem of existing diagnostic methods for chronic gastritis which are complex and traumatic, a novel noninvasive method for diagnosis of chronic gastric based on e‐nose and deep convolutional neural network is proposed. Firstly, in order to collect samples, a respiratory gas sampling device was established and the response curve of respiratory gas is generated. Then, a deep convolutional neural network for the diagnosis of chronic gastritis is proposed to recognize and classify the respiratory gas response curve. The DCNN model attained good results with accuracy, sensitivity, and specificity of 85.00%, 90.00%, and 80.00%, respectively, for chronic gastric prediction. The proposed method provides a new way for the clinical auxiliary diagnoses of chronic gastric.