Resonant tunnelling diodes (RTDs) have negative differential resistance effect, and the current-voltage characteristics change as a function of external stress, which is regarded as mesc-piezoresistance effect of RT...Resonant tunnelling diodes (RTDs) have negative differential resistance effect, and the current-voltage characteristics change as a function of external stress, which is regarded as mesc-piezoresistance effect of RTDs. In this paper, a novel micro-accelerometer based on AlAs/GaAs/In0.1Ga0.9As/GaAs/AlAs RTDs is designed and fabricated to be a four-beam-mass structure, and an RTD-Wheatstone bridge measurement system is established to test the basic properties of this novel accelerometer. According to the experimental results, the sensitivity of the RTD based micro-accelerometer is adjustable within a range of 3 orders when the bias voltage of the sensor changes. The largest sensitivity of this RTD based miero-accelerometer is 560.2025 mV/g which is about 10 times larger than that of silicon based micro piezoresistive accelerometer, while the smallest one is 1.49135 mV/g.展开更多
For the microaccelerometer, strong axial response and weak cross-axial one are always expected. This paper presents a general analysis about transverse sensitivity of the microaccelerometer. The analysis model is deve...For the microaccelerometer, strong axial response and weak cross-axial one are always expected. This paper presents a general analysis about transverse sensitivity of the microaccelerometer. The analysis model is developed, where the influence of response stiffness and damping in different axes, as well as symmetrical decline angles of 3 degrees of freedom system is considered. Moreover, multi-freedom vibration equations based on the analysis model are established. And the equations are solved on condition that damping force is ignored. Finally, the theoretical analysis about transverse sensitivity is accomplished, and some effective methods, which are beneficial to reduce cross disturbance, are provided.展开更多
Based on a conventional torsion pendulum,we develop a forced oscillation viscometer with ultra-high viscosity sensitivity of 2×10^(-7)Pa·s working at frequencies near the resonance.The viscosity is achieve...Based on a conventional torsion pendulum,we develop a forced oscillation viscometer with ultra-high viscosity sensitivity of 2×10^(-7)Pa·s working at frequencies near the resonance.The viscosity is achieved by exploiting the phase lag for the angle displacement behind the torque,instead of the resonant curve,i.e.,the variation of angle displacement amplitude versus frequency.The general formula for the measurement of the visco-elasticit.y of complex fluids is also presented.With such precision it is easy to measure tiny change in viscosity result from circumstantial influences.Deionized water and two kinds of NaCl aqueous solutions are chosen to demonstrate the performance of our home-made torsion pendulum-based viscometer.展开更多
High-performance connection frames are of great significance for ultra-high acceleration and ultra-precision positioning in macro-micro motion platforms. This paper first takes the connection frame as a research objec...High-performance connection frames are of great significance for ultra-high acceleration and ultra-precision positioning in macro-micro motion platforms. This paper first takes the connection frame as a research object,builds a finite element model(FEM) of the natural frequency of the frame, and then verifies the correctness of this model. The frequency sensitivity method is then used to perturb the structural parameters of the FEM of the connection frame, and the sensitivities of the first-order natural frequency and mass of the corresponding structural parameters are obtained by calculation and analysis. The design variables are also determined. The natural frequency is used as the optimization objective, and the design parameters and mass of the connection frame are constrained. The structural parameters of the connecting frame are obtained through optimization, and the model is built and verified by experiments. The results show that the first-order natural frequency of the connecting frame is effectively improved by the frequency sensitivity method, avoids resonance between the connecting frame and the voice coil motor, and realizes the lightweight design of the connection frame. This research provides a reliable basis for the stable operation and ultra-precision positioning of ultra-high acceleration macro-motion platforms.展开更多
There exist several difficulties in the design of monolithic high-shock three-axis accelerometer, such as high g overload, transverse overload and the cross coupling in three dimensions, etc. It is necessary to optimi...There exist several difficulties in the design of monolithic high-shock three-axis accelerometer, such as high g overload, transverse overload and the cross coupling in three dimensions, etc. It is necessary to optimize the sensitivity to improve the performance of the accelerometer. For the monolithic high-shock three-axis accelerometer, the complexity of the sensitivity optimization is that it should consider not only the sensitivity difference between different axes but also the elimination of cross-coupling outputs, together with the natural frequency, structural integrity and high g overload. In this paper, the optimization process for decreasing the difference of the sensitivities between different axes of a monolithic high-shock three-axis piezoresistive accelerometer with single sensing element is established. The optimization is conducted in the condition of 100000 g acceleration by two methods-the method based on the optimization module of ANSYS and the ACO (ant colony optimization) method. The comparison between un-optimized and optimized models proves the efficiency of the optimization methods. In addition, the optimization results show that the ACO method combined with the FEA (finite element analysis) is much more efficient than the method based on the optimization module of ANSYS for the structural optimization problem. And the ACO method can be widely used in the optimization problem of the sensing elements with complicated structure.展开更多
Surface acoustic wave (SAW) technology has been extensively explored for wireless communication, sensors, microfluidics, photonics, and quantum information processing. However, due to fabrication issues, the frequenci...Surface acoustic wave (SAW) technology has been extensively explored for wireless communication, sensors, microfluidics, photonics, and quantum information processing. However, due to fabrication issues, the frequencies of SAW devices are typically limited to within a few gigahertz, which severely restricts their applications in 5G communication, precision sensing, photonics, and quantum control. To solve this critical problem, we propose a hybrid strategy that integrates a nanomanufacturing process (i.e., nanolithography) with a LiNbO_(3)/SiO_(2)/SiC heterostructure and successfully achieve a record-breaking frequency of about 44 GHz for SAW devices, in addition to large electromechanical coupling coefficients of up to 15.7%. We perform a theoretical analysis and identify the guided higher order wave modes generated on these slow-on-fast SAW platforms. To demonstrate the superior sensing performance of the proposed ultra-high-frequency SAW platforms, we perform micro-mass sensing and obtain an extremely high sensitivity of approximately 33151.9 MHz·mm2·μg−1, which is about 1011 times higher than that of a conventional quartz crystal microbalance (QCM) and about 4000 times higher than that of a conventional SAW device with a frequency of 978 MHz.展开更多
基金supported in part by the National Natural Science Foundation of China (Grant No 50775209)the Fork Ying Tung Education Foundation (Grant No 101052)Program for Excellent Talents by Ministry of Education of China
文摘Resonant tunnelling diodes (RTDs) have negative differential resistance effect, and the current-voltage characteristics change as a function of external stress, which is regarded as mesc-piezoresistance effect of RTDs. In this paper, a novel micro-accelerometer based on AlAs/GaAs/In0.1Ga0.9As/GaAs/AlAs RTDs is designed and fabricated to be a four-beam-mass structure, and an RTD-Wheatstone bridge measurement system is established to test the basic properties of this novel accelerometer. According to the experimental results, the sensitivity of the RTD based micro-accelerometer is adjustable within a range of 3 orders when the bias voltage of the sensor changes. The largest sensitivity of this RTD based miero-accelerometer is 560.2025 mV/g which is about 10 times larger than that of silicon based micro piezoresistive accelerometer, while the smallest one is 1.49135 mV/g.
文摘For the microaccelerometer, strong axial response and weak cross-axial one are always expected. This paper presents a general analysis about transverse sensitivity of the microaccelerometer. The analysis model is developed, where the influence of response stiffness and damping in different axes, as well as symmetrical decline angles of 3 degrees of freedom system is considered. Moreover, multi-freedom vibration equations based on the analysis model are established. And the equations are solved on condition that damping force is ignored. Finally, the theoretical analysis about transverse sensitivity is accomplished, and some effective methods, which are beneficial to reduce cross disturbance, are provided.
基金Supported by the National Natural Science Foundation of China under Grant Nos 10974259,11274391 and 11104357the Science and Technology Planning Project of Guangdong Province under Grant No 20128060100003the Fundamental Research Funds for the Central Universities under Grant Nos 121gpy36 and 09lgpy29
文摘Based on a conventional torsion pendulum,we develop a forced oscillation viscometer with ultra-high viscosity sensitivity of 2×10^(-7)Pa·s working at frequencies near the resonance.The viscosity is achieved by exploiting the phase lag for the angle displacement behind the torque,instead of the resonant curve,i.e.,the variation of angle displacement amplitude versus frequency.The general formula for the measurement of the visco-elasticit.y of complex fluids is also presented.With such precision it is easy to measure tiny change in viscosity result from circumstantial influences.Deionized water and two kinds of NaCl aqueous solutions are chosen to demonstrate the performance of our home-made torsion pendulum-based viscometer.
基金financially supported by the National Natural Science Foundation of China (Grant No. 51705132)the Science and Technology Department of Henan Province Natural Science Project (Grant No. 172102210215)+1 种基金Henan Postdoctoral Foundation, doctoral Foundation (2016BS008)the Education Department of Henan Province Natural Science Project (Grant No. 17A460008)
文摘High-performance connection frames are of great significance for ultra-high acceleration and ultra-precision positioning in macro-micro motion platforms. This paper first takes the connection frame as a research object,builds a finite element model(FEM) of the natural frequency of the frame, and then verifies the correctness of this model. The frequency sensitivity method is then used to perturb the structural parameters of the FEM of the connection frame, and the sensitivities of the first-order natural frequency and mass of the corresponding structural parameters are obtained by calculation and analysis. The design variables are also determined. The natural frequency is used as the optimization objective, and the design parameters and mass of the connection frame are constrained. The structural parameters of the connecting frame are obtained through optimization, and the model is built and verified by experiments. The results show that the first-order natural frequency of the connecting frame is effectively improved by the frequency sensitivity method, avoids resonance between the connecting frame and the voice coil motor, and realizes the lightweight design of the connection frame. This research provides a reliable basis for the stable operation and ultra-precision positioning of ultra-high acceleration macro-motion platforms.
基金Supported by the "111" Project (Grant No. B08043)Foundation Program of National Key Lab for Electronic Measurement and Technology (Grant No. 9140C12040606060C12)
文摘There exist several difficulties in the design of monolithic high-shock three-axis accelerometer, such as high g overload, transverse overload and the cross coupling in three dimensions, etc. It is necessary to optimize the sensitivity to improve the performance of the accelerometer. For the monolithic high-shock three-axis accelerometer, the complexity of the sensitivity optimization is that it should consider not only the sensitivity difference between different axes but also the elimination of cross-coupling outputs, together with the natural frequency, structural integrity and high g overload. In this paper, the optimization process for decreasing the difference of the sensitivities between different axes of a monolithic high-shock three-axis piezoresistive accelerometer with single sensing element is established. The optimization is conducted in the condition of 100000 g acceleration by two methods-the method based on the optimization module of ANSYS and the ACO (ant colony optimization) method. The comparison between un-optimized and optimized models proves the efficiency of the optimization methods. In addition, the optimization results show that the ACO method combined with the FEA (finite element analysis) is much more efficient than the method based on the optimization module of ANSYS for the structural optimization problem. And the ACO method can be widely used in the optimization problem of the sensing elements with complicated structure.
基金supported by the National Science Foundation of China(NSFC)(52075162)the Program of New and High-Tech Industry of Hunan Province(2020GK2015 and 2021GK4014)+5 种基金the Excellent Youth Fund of Hunan Province(2021JJ20018)the Key Program of Guangdong(2020B0101040002)the Joint Fund of the Ministry of Education(Young Talents)the Natural Science Foundation of Changsha(kq2007026)the Tianjin Enterprise Science and Technology Commissioner Project(19JCTPJC56200)the Engineering Physics and Science Research Council of the United Kingdom(EPSRC EP/P018998/1).
文摘Surface acoustic wave (SAW) technology has been extensively explored for wireless communication, sensors, microfluidics, photonics, and quantum information processing. However, due to fabrication issues, the frequencies of SAW devices are typically limited to within a few gigahertz, which severely restricts their applications in 5G communication, precision sensing, photonics, and quantum control. To solve this critical problem, we propose a hybrid strategy that integrates a nanomanufacturing process (i.e., nanolithography) with a LiNbO_(3)/SiO_(2)/SiC heterostructure and successfully achieve a record-breaking frequency of about 44 GHz for SAW devices, in addition to large electromechanical coupling coefficients of up to 15.7%. We perform a theoretical analysis and identify the guided higher order wave modes generated on these slow-on-fast SAW platforms. To demonstrate the superior sensing performance of the proposed ultra-high-frequency SAW platforms, we perform micro-mass sensing and obtain an extremely high sensitivity of approximately 33151.9 MHz·mm2·μg−1, which is about 1011 times higher than that of a conventional quartz crystal microbalance (QCM) and about 4000 times higher than that of a conventional SAW device with a frequency of 978 MHz.