다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

A strain sensor has been fabricated from a polymer nanocomposite with multiwalled carbon nanotube (MWNT) fillers. The piezoresistivity
of this nanocomposite strain sensor has been investigated based on an improved three-dimensional (3D) statistical resistor network
model incorporating the tunneling effect between the neighboring carbon nanotubes (CNTs), and a fiber reorientation model. The
numerical results agree very well with the experimental measurements. As compared with traditional strain gauges, much higher sensitivity
can be obtained in the nanocomposite sensors when the volume fraction of CNT is close to the percolation threshold. For a small
CNT volume fraction, weak nonlinear piezoresistivity is observed both experimentally and from numerical simulation. The tunneling
effect is considered to be the principal mechanism of the sensor under small strains.

Tunneling effect in a polymer/carbon nanotube nanocompositestrain sensor

Conductive MXene/cotton fabric based pressure sensor with both high sensitivity and wide sensing range for human motion detection and E-skin

Recent Progress in Flexible Microstructural Pressure Sensors toward Human–Machine Interaction and Healthcare Applications

For a long time, the daily paper and carbon ink have been used for writing and painting. With the development of the electronic technology, they are expected to play new roles in electronic devices. Herein, combining the unique characteristics of the paper (rough surface, hydrophilicity) and carbon ink (conductivity), this work rationally proposed two low-cost, eco-friendly, flexible, multifunctional pressure and humidity sensors. The results show that as-fabricated paper-based (PB) pressure sensor has a good sensitivity of 0.614 kPa−1 in the pressure range of 0–6 kPa. The PB humidity sensor has a large response of ∼2120 (current ratio at 91.5% relative humidity (RH) and 0% RH). The PB pressure sensor is proven to be useful for multiple pressure related contact detections, and the PB humidity sensor can be used for many humidity related non-contact detections. Interestingly, combining the different detecting modes of pressure and humidity sensors, some same detecting functions (e.g. switch, respiratory frequency and speech recognition) are realized from contact to non-contact using PB pressure and humidity sensors, which greatly enhance the wearable comfort. Compared with previous reports, this work demonstrates a much simpler approach without expensive raw materials, toxic reagents and high temperature treatment to achieve outstanding sensing performances of the multifunctional pressure and humidity sensors.

Paper and carbon ink enabled low-cost, eco-friendly, flexible, multifunctional pressure and humidity sensors

Flexible pressure sensors have attracted considerable research interest and efforts owing to their broad application prospects in wearable devices, health monitoring, and human–machine interfacing....

Ultrawide Sensing Range and Highly Sensitive Flexible Pressure Sensor Based on a Percolative Thin Film with a Knoll-like Microstructured Surface

In this paper, a flexible three-dimensional (3D) force sensor utilizing the piezoresistive principle has been manufactured. The proposed sensor is designed as four pressure sensing resistors embedded in a flexible substrate. The piezoresistive PI film is used to be sensing material, as its effective pressure sensitivity, good linearity, and low hysteresis. The bump built on top of the sensor convert an applied force to the mechanical stress, and changes the resistances of the four sensing cells. The normal and shear forces can be therefore detected by the resistance responses. Calibration and test experiments have been conducted to characterize the 3D force sensor. The results demonstrate that the sensor is capable of 3D force measurement with good linear responses and sensitivity. The proposed 3D force sensor could be suitable for tactile sensing in intelligent robots, and other applications requiring three-dimensional force detection.

A flexible three-dimensional force sensor based on PI piezoresistive film

Highly sensitive printed crack-enhanced strain sensor as dual-directional bending detector

Flexible temperature sensors are needed for real‐time temperature monitoring in healthcare, disease diagnosis, and ambient environment detection. In this work, a flexible negative temperature coefficient (NTC) temperature sensor based on polyvinyl chloride/carbon black (PVC/CB) was screen printed onto a polyethylene terephthalate substrate. The prepared temperature sensor exhibited high sensitivity (−0.148% °C−1), excellent linearity (R 2 = 0.995), a fast response time (0.7 s), and good repeatability when used to measure temperatures between 18 °C and 44 °C. The tunneling effect was used to explain the NTC of the PVC/CB temperature sensor, and its temperature sensing mechanism was proposed. Additionally, the sensor was used to monitor human breathing rates and temperatures, demonstrating its potential for real‐time skin or environmental temperature monitoring.

Screen-printed flexible negative temperature coefficient temperature sensor based on polyvinyl chloride/carbon black composites

In this work, a crack-enhanced flexible strain sensor was developed based on polyimide/carbon black piezoresistive polymer composite. A simple, cost-efficient approach to introduce micro-cracks into the sensitive film was proposed. By periodically tearing the sensitive film from a supporting layer, the aligned micro-cracks were generated in the sensitive film, and the crack size and density were modulated by repeated tearing-off times and finally saturated. This crack-enhanced strain sensor exhibited high mechano-sensitivity with a gauge factor of ~470 at 0.2% strain. We demonstrated that the crack-enhanced strain sensor was capable of monitoring the body joint motion. In particular, the patterns of finger grabbing and elbow bending could be detected and distinguished using this sensor. The high sensitivity of this crack-based strain sensor, together with its low hysteresis, good repeatability and simplicity, low cost in fabrication, make it suitable for motion detection and recognition.

https://iopscience.iop.org/article/10.1088/1361-665X/aadc89/pdf

Yao Xiao

Papers

Ultrawide Sensing Range and Highly Sensitive Flexible Pressure Sensor Based on a Percolative Thin Film with a Knoll-like Microstructured Surface

A flexible three-dimensional force sensor based on PI piezoresistive film

Highly sensitive printed crack-enhanced strain sensor as dual-directional bending detector

Screen-printed flexible negative temperature coefficient temperature sensor based on polyvinyl chloride/carbon black composites

Crack-enhanced mechanosensitivity of cost-effective piezoresistive flexible strain sensors suitable for motion detection