A two-year field observation of saltation activity was carried out at Tazhong area, the hinterland area of the Taklimakan Desert with highly frequent dust storms. From 1 September 2008 to 31 August 2010, a piezoelectr...A two-year field observation of saltation activity was carried out at Tazhong area, the hinterland area of the Taklimakan Desert with highly frequent dust storms. From 1 September 2008 to 31 August 2010, a piezoelectric saltation sensor （Sensit） was used to continuously collect the data on saltation activity at a level sand surface. Analysis on the data suggests that saltation activity can occur at any time of the year when conditions are favorable; however, the necessary conditions are rarely satisfied in most time. In the daytime of spring or summer, saltation activity can persist even over a continuous one-hour-or-so period. It is found that, from 1 September 2008 to 31 August 2010, saltation activity accounts for more than 3% of the total yearly time, and it tends to peak in spring and summer months with strong winds. During winter months when winds are weak, however, it is often at a minimum. It seems that precipitation does not appear to be significant in reducing saltation activity in arid regions like Tazhong.展开更多
Designing stretchable and skin-conformal self-powered sensors for intelligent sensing and posture recognition is challenging.Here,based on a multi-force mixing and vulcanization process,as well as synergistically piez...Designing stretchable and skin-conformal self-powered sensors for intelligent sensing and posture recognition is challenging.Here,based on a multi-force mixing and vulcanization process,as well as synergistically piezoelectricity of BaTiO_(3)and polyacrylonitrile,an all-in-one,stretchable,and self-powered elastomer-based piezo-pressure sensor(ASPS)with high sensitivity is reported.The ASPS presents excellent sensitivity(0.93 V/104 Pa of voltage and 4.92 nA/104 Pa of current at a pressure of 10-200 kPa)and high durability(over 10,000 cycles).Moreover,the ASPS exhibits a wide measurement range,good linearity,rapid response time,and stable frequency response.All components were fabricated using silicone,affording satisfactory skinconformality for sensing postures.Through cooperation with a homemade circuit and artificial intelligence algorithm,an information processing strategy was proposed to realize intelligent sensing and recognition.The home-made circuit achieves the acquisition and wireless transmission of ASPS signals(transmission distance up to 50 m),and the algorithm realizes the classification and identification of ASPS signals(accuracy up to 99.5%).This study proposes not only a novel fabrication method for developing self-powered sensors,but also a new information processing strategy for intelligent sensing and recognition,which offers significant application potential in human-machine interaction,physiological analysis,and medical research.展开更多
Background: Prostate cancer (PCa) is the most common form of cancer among males in Europe and in the USA and the most common curative treatment is removal of the prostate, i.e. prostatectomy. After the removal, the pr...Background: Prostate cancer (PCa) is the most common form of cancer among males in Europe and in the USA and the most common curative treatment is removal of the prostate, i.e. prostatectomy. After the removal, the prostate is histopathologically analysed. One area of interest is to examine the perifery of the prostate, as tumours on and near the surface can indicate that the PCa has spread to other parts of the body. There are no current methods to examine the surface of the prostate at the time of surgery. Tactile resonance sensors can be used for detecting areas of different stiffness in soft tissue. Human prostate tissue affected by cancer is usually stiffer than healthy tissue, and for this purpose, a tactile resonance sensor was developed. The aim of this study was to investigate the depth at which embedded stiffer volumes could be detected, using soft tissue phantoms. Methods: With the tactile resonance sensor used in this study, the shift of the resonance frequency and the force at contact with tissue can be measured, and combined into a tissue stiffness parameter. The detection sensitivity of the sensor at impression depths, 0.4 and 0.8 mm, was measured for detection of inserted nodules of stiff silicone in softer silicone and in chicken muscle tissue, mimicking prostate tissue with cancer tumours. Results: Measurements on the silicone samples detected the hidden stiffer object at a depth of 1 - 4 mm with a difference in the stiffness parameter of 80 - 900 mN/kHz (p < 0.028, n = 48). At the depth 5 - 6 mm the difference was smaller but still significant < 30 mN/kHz (p < 0.05, n = 24). For the measurements on chicken muscle, the detectable depth was 4 mm (p < 0.05, n = 24). Conclusion: This model study suggests that, with only a small impression depth of ≤1 mm, the resonance sensor system described here can detect stiffness variations located at least 4 mm in silicone and chicken muscle, mimicking tumours in prostate tissue.展开更多
Crickets, similar to some other insects, have highly sensitive filiform hairs on their cerci that can detect miniscule changes in airflow. This study imitates the perception mechanism of these filiform sensory hairs o...Crickets, similar to some other insects, have highly sensitive filiform hairs on their cerci that can detect miniscule changes in airflow. This study imitates the perception mechanism of these filiform sensory hairs of crickets by designing and fabricating a Multi-electrode Metal Core Piezoelectric Fiber （MMPF）-based airflow sensor. Four longitudinal conductive sheets were coated symmetrically on their surfaces with Metal-core Piezoceramic Fibers （MPF）. The four fan-shaped piezoelectric ceramics with surface electrode covers were polarized. After successful polarization, the cantilevered MMPF could be used as an airflow sensor. The four electrodes on the surface were symmetrically divided into two groups. Therefore, two signals can be produced by a single fiber sensor. The theoretical model of an MMPF airflow sensor has been established. The model indicates that the ratio of the two signals is equivalent to the tangent of the airflow angle. Furthermore, the sum of the squares of the two signals is not dependent on the angle, but reflects the velocity of the airflow. Therefore, a single MMPF can be used to measure both the direction and amplitude for a given airflow. The theoretical model has been confirmed via experimental measurements.展开更多
基金funded by the National Natural Science Foundation of China (41175017,41175140)the R & DSpecial Fund for Public Welfare Industry (meteorology)(GYHY201006012,GYHY201106025)
文摘A two-year field observation of saltation activity was carried out at Tazhong area, the hinterland area of the Taklimakan Desert with highly frequent dust storms. From 1 September 2008 to 31 August 2010, a piezoelectric saltation sensor （Sensit） was used to continuously collect the data on saltation activity at a level sand surface. Analysis on the data suggests that saltation activity can occur at any time of the year when conditions are favorable; however, the necessary conditions are rarely satisfied in most time. In the daytime of spring or summer, saltation activity can persist even over a continuous one-hour-or-so period. It is found that, from 1 September 2008 to 31 August 2010, saltation activity accounts for more than 3% of the total yearly time, and it tends to peak in spring and summer months with strong winds. During winter months when winds are weak, however, it is often at a minimum. It seems that precipitation does not appear to be significant in reducing saltation activity in arid regions like Tazhong.
基金supported by the National Natural Science Foundation of China(Nos.62101513,51975542,52175554,and 62171414)China Postdoctoral Science Foundation(Nos.2022TQ0230 and 2022M712324)+2 种基金Shanxi“1331 Project”Key Subject Construction(No.1331KSC)the Fundamental Research Program of Shanxi Province(No.20210302124170)Young Academic Leaders of North University of China(No.11045501).
文摘Designing stretchable and skin-conformal self-powered sensors for intelligent sensing and posture recognition is challenging.Here,based on a multi-force mixing and vulcanization process,as well as synergistically piezoelectricity of BaTiO_(3)and polyacrylonitrile,an all-in-one,stretchable,and self-powered elastomer-based piezo-pressure sensor(ASPS)with high sensitivity is reported.The ASPS presents excellent sensitivity(0.93 V/104 Pa of voltage and 4.92 nA/104 Pa of current at a pressure of 10-200 kPa)and high durability(over 10,000 cycles).Moreover,the ASPS exhibits a wide measurement range,good linearity,rapid response time,and stable frequency response.All components were fabricated using silicone,affording satisfactory skinconformality for sensing postures.Through cooperation with a homemade circuit and artificial intelligence algorithm,an information processing strategy was proposed to realize intelligent sensing and recognition.The home-made circuit achieves the acquisition and wireless transmission of ASPS signals(transmission distance up to 50 m),and the algorithm realizes the classification and identification of ASPS signals(accuracy up to 99.5%).This study proposes not only a novel fabrication method for developing self-powered sensors,but also a new information processing strategy for intelligent sensing and recognition,which offers significant application potential in human-machine interaction,physiological analysis,and medical research.
基金supported by The Industrial Doctoral School at Umea University and by grants from Objective 2 North Sweden-EU Structural Fund.
文摘Background: Prostate cancer (PCa) is the most common form of cancer among males in Europe and in the USA and the most common curative treatment is removal of the prostate, i.e. prostatectomy. After the removal, the prostate is histopathologically analysed. One area of interest is to examine the perifery of the prostate, as tumours on and near the surface can indicate that the PCa has spread to other parts of the body. There are no current methods to examine the surface of the prostate at the time of surgery. Tactile resonance sensors can be used for detecting areas of different stiffness in soft tissue. Human prostate tissue affected by cancer is usually stiffer than healthy tissue, and for this purpose, a tactile resonance sensor was developed. The aim of this study was to investigate the depth at which embedded stiffer volumes could be detected, using soft tissue phantoms. Methods: With the tactile resonance sensor used in this study, the shift of the resonance frequency and the force at contact with tissue can be measured, and combined into a tissue stiffness parameter. The detection sensitivity of the sensor at impression depths, 0.4 and 0.8 mm, was measured for detection of inserted nodules of stiff silicone in softer silicone and in chicken muscle tissue, mimicking prostate tissue with cancer tumours. Results: Measurements on the silicone samples detected the hidden stiffer object at a depth of 1 - 4 mm with a difference in the stiffness parameter of 80 - 900 mN/kHz (p < 0.028, n = 48). At the depth 5 - 6 mm the difference was smaller but still significant < 30 mN/kHz (p < 0.05, n = 24). For the measurements on chicken muscle, the detectable depth was 4 mm (p < 0.05, n = 24). Conclusion: This model study suggests that, with only a small impression depth of ≤1 mm, the resonance sensor system described here can detect stiffness variations located at least 4 mm in silicone and chicken muscle, mimicking tumours in prostate tissue.
基金This research was supported by the Nationa Natural Science Foundation of China （Grant No 51275447）.
文摘Crickets, similar to some other insects, have highly sensitive filiform hairs on their cerci that can detect miniscule changes in airflow. This study imitates the perception mechanism of these filiform sensory hairs of crickets by designing and fabricating a Multi-electrode Metal Core Piezoelectric Fiber （MMPF）-based airflow sensor. Four longitudinal conductive sheets were coated symmetrically on their surfaces with Metal-core Piezoceramic Fibers （MPF）. The four fan-shaped piezoelectric ceramics with surface electrode covers were polarized. After successful polarization, the cantilevered MMPF could be used as an airflow sensor. The four electrodes on the surface were symmetrically divided into two groups. Therefore, two signals can be produced by a single fiber sensor. The theoretical model of an MMPF airflow sensor has been established. The model indicates that the ratio of the two signals is equivalent to the tangent of the airflow angle. Furthermore, the sum of the squares of the two signals is not dependent on the angle, but reflects the velocity of the airflow. Therefore, a single MMPF can be used to measure both the direction and amplitude for a given airflow. The theoretical model has been confirmed via experimental measurements.
