A fluid sensor based on the surface transverse wave (STW) delay line on ST-cut quartz has been developed and tested in a large number of fluids with different viscosity and permittivity levels.Influence of fluid mech...A fluid sensor based on the surface transverse wave (STW) delay line on ST-cut quartz has been developed and tested in a large number of fluids with different viscosity and permittivity levels.Influence of fluid mechanical and electrical properties on the sensor's response has been determined and the sensor's performance has been compared with a bulk acoustic wave (BAW) viscosity sensor.The result shows that the viscosity sensitivity of the developed STW sensor represented by the signal to noise ratio is lower than that of a 5 MHz BAW sensor.Applications of the sensor in detecting the quality of industrial fluids are discussed.展开更多
An electronic-nose is developed based on eight quartz-crystal-microbalance (QCM) gas sensors in a sensor box, and is used to detect Chinese liquors at room temperature. Each sensor is a highly-accurate and highly-sens...An electronic-nose is developed based on eight quartz-crystal-microbalance (QCM) gas sensors in a sensor box, and is used to detect Chinese liquors at room temperature. Each sensor is a highly-accurate and highly-sensitive oscillator that has experienced airflow disturbances under the condition of varying room temperatures due to unstable flow-induced forces on the sensors surfaces. The three-dimensional (3D) nature of the airflow inside the sensor box and the interactions of the airflow on the sensors surfaces at different temperatures are studied by computational fluid dynamics (CFD) tools. Higher simulation accuracy is achieved by optimizing meshes, meshing the computational domain using a fine unstructural tetrahedron mesh. An optimum temperature, 30 ℃, is obtained by analyzing the distributions of velocity streamlines and the static pressure, as well as the flow-induced forces over time, all of which may be used to improve the identification accuracy of the electronic-nose for achieving stable and repeatable signals by removing the influence of temperature.展开更多
An electrochemically pretreated silver macroporous(Ag MP) multiwalled carbon nanotube modified glassy carbon electrode(PAN-Ag MP-MWCNT-GCE) was fabricated for the selective determination of an antihyperlipidimic drug,...An electrochemically pretreated silver macroporous(Ag MP) multiwalled carbon nanotube modified glassy carbon electrode(PAN-Ag MP-MWCNT-GCE) was fabricated for the selective determination of an antihyperlipidimic drug, pitavastatin(PST). The fabricated electrochemical sensor was characterized by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS). The fabricated electrode was employed in quantifying and determining PST through differential pulse adsorptive stripping voltammetry(DPAdSV) and CV. The electrode fabrication proceeded with remarkable sensitivity to the determination of PST. The effect of various optimized parameters such as pH, scan rate(ν), accumulation time(t_(acc)), accumulation potential(U_(acc))and loading volumes of Ag MP-MWCNT suspension were investigated to evaluate the performance of synthesized electrochemical sensor and to propose a simple, accurate, rapid and economical procedure for the quantification of PST in pharmaceutical formulations and biological fluids. A linear response of PST concentration in the range 2.0×10^(-7)–1.6×10^(-6)M with low detection(LOD) and quantification(LOQ) limits of 9.66 ± 0.04 nM and 32.25 ± 0.07 nM, respectively, were obtained under these optimized conditions.展开更多
A CFD(Computational Fluid Dynamics) model has been developed using the commercial CFD package FLUENT for the thermal convection inside air filled cylindrical DACON sensor, where the onboard time dependent gravitationa...A CFD(Computational Fluid Dynamics) model has been developed using the commercial CFD package FLUENT for the thermal convection inside air filled cylindrical DACON sensor, where the onboard time dependent gravitational micro acceleration has been considered. Time dependent, curve fitted gravitational accelera-tion in x- and y-axes from published data have been incorporated in FLUENT through a User Defined Function (UDF), developed in C which includes space craft rotation. At the sensor plane the two-dimensional flow has also been visualized. A good agreement is between simu-lation and published experimental data. Last but not the least, for checking its response to suffi-ciently strong perturbations in an orbital flight, physical and numerical experiments are carried out where an astronaut swung the sensor in hands along the y axis with amplitude of 10cm and a frequency of 0.2 Hz. A good qualitative validation has been achieved between CFD and actual experimental results.展开更多
In order to discuss the several applications of MEMS in fluid area,study the components of MEMS.And introduce the principles,types and applications based on flow sensor and pressure sensor. In the last,discuss the pro...In order to discuss the several applications of MEMS in fluid area,study the components of MEMS.And introduce the principles,types and applications based on flow sensor and pressure sensor. In the last,discuss the problems when the sensors was applied in the fluid areas.展开更多
文摘A fluid sensor based on the surface transverse wave (STW) delay line on ST-cut quartz has been developed and tested in a large number of fluids with different viscosity and permittivity levels.Influence of fluid mechanical and electrical properties on the sensor's response has been determined and the sensor's performance has been compared with a bulk acoustic wave (BAW) viscosity sensor.The result shows that the viscosity sensitivity of the developed STW sensor represented by the signal to noise ratio is lower than that of a 5 MHz BAW sensor.Applications of the sensor in detecting the quality of industrial fluids are discussed.
基金Project supported by the National Natural Science Foundation of China(Nos.61876059 and U1501251)
文摘An electronic-nose is developed based on eight quartz-crystal-microbalance (QCM) gas sensors in a sensor box, and is used to detect Chinese liquors at room temperature. Each sensor is a highly-accurate and highly-sensitive oscillator that has experienced airflow disturbances under the condition of varying room temperatures due to unstable flow-induced forces on the sensors surfaces. The three-dimensional (3D) nature of the airflow inside the sensor box and the interactions of the airflow on the sensors surfaces at different temperatures are studied by computational fluid dynamics (CFD) tools. Higher simulation accuracy is achieved by optimizing meshes, meshing the computational domain using a fine unstructural tetrahedron mesh. An optimum temperature, 30 ℃, is obtained by analyzing the distributions of velocity streamlines and the static pressure, as well as the flow-induced forces over time, all of which may be used to improve the identification accuracy of the electronic-nose for achieving stable and repeatable signals by removing the influence of temperature.
文摘An electrochemically pretreated silver macroporous(Ag MP) multiwalled carbon nanotube modified glassy carbon electrode(PAN-Ag MP-MWCNT-GCE) was fabricated for the selective determination of an antihyperlipidimic drug, pitavastatin(PST). The fabricated electrochemical sensor was characterized by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS). The fabricated electrode was employed in quantifying and determining PST through differential pulse adsorptive stripping voltammetry(DPAdSV) and CV. The electrode fabrication proceeded with remarkable sensitivity to the determination of PST. The effect of various optimized parameters such as pH, scan rate(ν), accumulation time(t_(acc)), accumulation potential(U_(acc))and loading volumes of Ag MP-MWCNT suspension were investigated to evaluate the performance of synthesized electrochemical sensor and to propose a simple, accurate, rapid and economical procedure for the quantification of PST in pharmaceutical formulations and biological fluids. A linear response of PST concentration in the range 2.0×10^(-7)–1.6×10^(-6)M with low detection(LOD) and quantification(LOQ) limits of 9.66 ± 0.04 nM and 32.25 ± 0.07 nM, respectively, were obtained under these optimized conditions.
文摘A CFD(Computational Fluid Dynamics) model has been developed using the commercial CFD package FLUENT for the thermal convection inside air filled cylindrical DACON sensor, where the onboard time dependent gravitational micro acceleration has been considered. Time dependent, curve fitted gravitational accelera-tion in x- and y-axes from published data have been incorporated in FLUENT through a User Defined Function (UDF), developed in C which includes space craft rotation. At the sensor plane the two-dimensional flow has also been visualized. A good agreement is between simu-lation and published experimental data. Last but not the least, for checking its response to suffi-ciently strong perturbations in an orbital flight, physical and numerical experiments are carried out where an astronaut swung the sensor in hands along the y axis with amplitude of 10cm and a frequency of 0.2 Hz. A good qualitative validation has been achieved between CFD and actual experimental results.
文摘In order to discuss the several applications of MEMS in fluid area,study the components of MEMS.And introduce the principles,types and applications based on flow sensor and pressure sensor. In the last,discuss the problems when the sensors was applied in the fluid areas.
