Spacecrafts free of all but gravitational forces are important in precision navigation,gravity field measurement and basic scientific research.The Inner-formation Flying System,one kind of spacecrafts free of all but ...Spacecrafts free of all but gravitational forces are important in precision navigation,gravity field measurement and basic scientific research.The Inner-formation Flying System,one kind of spacecrafts free of all but gravitational forces,is used for gravitational field measurement with high precision.Restraining the interfering factors on the inner-satellite is one of the keys to gravitational field measurement.Radiometer effect and residual gas damping are both interfering forces on the inner-satellite caused by gas molecules.By analyzing the mechanism of the two forces,a coupled model for radiometer effect and residual gas damping was established,which contained the coupling term and reflected the actual force of gas molecules on the inner-satellite.The simulation results showed the coupling property of radiometer effect and residual gas damping:The actual force of gas molecules is directly proportional to the average pressure in the cavity and the largest cross-sectional area of the inner-satellite,but is inversely proportional to the square root of the average temperature in the cavity.展开更多
The wave/particle duality of particles in Physics is well known. Particles have properties that uniquely characterize them from one another, such as mass, charge and spin. Charged particles have associated Electric an...The wave/particle duality of particles in Physics is well known. Particles have properties that uniquely characterize them from one another, such as mass, charge and spin. Charged particles have associated Electric and Magnetic fields. Also, every moving particle has a De Broglie wavelength determined by its mass and velocity. This paper shows that all of these properties of a particle can be derived from a single wave function equation for that particle. Wave functions for the Electron and the Positron are presented and principles are provided that can be used to calculate the wave functions of all the fundamental particles in Physics. Fundamental particles such as electrons and positrons are considered to be point particles in the Standard Model of Physics and are not considered to have a structure. This paper demonstrates that they do indeed have structure and that this structure extends into the space around the particle’s center (in fact, they have infinite extent), but with rapidly diminishing energy density with the distance from that center. The particles are formed from Electromagnetic standing waves, which are stable solutions to the Schrödinger and Classical wave equations. This stable structure therefore accounts for both the wave and particle nature of these particles. In fact, all of their properties such as mass, spin and electric charge, can be accounted for from this structure. These particle properties appear to originate from a single point at the center of the wave function structure, in the same sort of way that the Shell theorem of gravity causes the gravity of a body to appear to all originate from a central point. This paper represents the first two fully characterized fundamental particles, with a complete description of their structure and properties, built up from the underlying Electromagnetic waves that comprise these and all fundamental particles.展开更多
A cantilever-structured magneto-mechano-electric(MME)generator comprising a magnetoelectric composite with a magnet proof mass is a potential candidate for powering autonomous wireless sensor networks.Recently,the con...A cantilever-structured magneto-mechano-electric(MME)generator comprising a magnetoelectric composite with a magnet proof mass is a potential candidate for powering autonomous wireless sensor networks.Recently,the concept of a magnetic flux concentrator(MFC)to enhance the output performance of the MME generator by focusing the ultralow-intensity magnetic field into the MME generator was introduced.However,the MFC-concentrated magnetic flux mostly focused on the end tip of the MME cantilever rather than at the magnet proof mass located on the cantilever beam.Considering that the torque generated by the magnet proof mass contributes more than half of the output power of an MME generator,optimizing the volume and position of the proof-mass with MFC is crucial for better performance.Furthermore,a smaller proof-mass is desirable for the long-term reliability of cantilevertype harvesters.Hence,we investigated the effect of the position and weight(volume)of the magnet proof mass with respect to the MFC on the output performance of the MME generator through finite element analysis and experiments.The MME generator with the lighter magnet proof mass at the optimized position generated a maximum power of 5.35 mW under a 10 Oe magnetic field,which was 210%of that of the MME configuration used in our previous study.Furthermore,the MME generator showed broadband characteristics around the practical frequency of 60 Hz,which could provide more freedom to design the harvester with high performance.展开更多
为获得传感器的优化设计,对一种声表面波梁式加速度传感器敏感机理进行了研究。从声波波动方程出发,结合有限元分析以及微扰理论对加速度作用力作用下声表面波传播特性进行分析,以此构建梁式声表面波加速度传感器敏感机理的理论模型,特...为获得传感器的优化设计,对一种声表面波梁式加速度传感器敏感机理进行了研究。从声波波动方程出发,结合有限元分析以及微扰理论对加速度作用力作用下声表面波传播特性进行分析,以此构建梁式声表面波加速度传感器敏感机理的理论模型,特别分析了压电梁材料及几何结构、振子质量对传感响应的贡献以确定传感器优化的几何参数。为验证理论分析结果,实验研制了基于ST-X石英悬臂梁结构的差分振荡式声表面波加速度传感器,并利用精密振动台对所研制传感器性能进行评价。实验结果显示,在给定加速度测试范围内,采用ST-X石英梁并延长梁长度、降低梁厚度以及采用较大的阵子质量将有效的改善传感器检测灵敏度,在±2 g范围内加速度灵敏度可达27 k Hz/g,且实验结果很好的验证了理论模型。展开更多
Spacecrafts with the pure gravity environment are of great significance in precision navigation, gravity field measurement for celestial bodies, and basic physics ex- periments. The radiometer effect is one of the imp...Spacecrafts with the pure gravity environment are of great significance in precision navigation, gravity field measurement for celestial bodies, and basic physics ex- periments. The radiometer effect is one of the important interfering factors on the proof mass in a purely gravitational orbit. For the gravity field measurement system based on the inner-formation flying, the relationship between the radiometer effect on the inner- satellite and the system parameters is studied by analytical and numerical methods. An approximate function of the radiometer effect suitable for the engineering computation and the correction factor are obtained. The analytic results show that the radiometer effect on the inner-satellite is proportional to the average pressure while inversely pro- portional to the average temperature in the outer-satellite cavity. The radiometer effect increases with the temperature difference in the cavity, and its minimum exists when the cavity radius increases. When the minimum of the radiometer effect arrives, the ratio of the cavity radius to the inner-satellite radius is 1.189 4. This constant is determined by the spherical cavity configuration and independent of the temperature and pressure distributions. When the ratio of the cavity radius to the inner-satellite radius is more than 10, it is believed that the cavity is large enough, the radiometer effect is approxi- mately proportional to the square of the inner-satellite radius, and the influence of the outer-satellite cavity radius on the radiometer effect can be ignored.展开更多
This paper presents a novel structure for improving the stability and the mechanical noise of micromachined gyroscopes. Only one slanted cantilever is used for suspension in this gyroscope, so the asymmetry spring and...This paper presents a novel structure for improving the stability and the mechanical noise of micromachined gyroscopes. Only one slanted cantilever is used for suspension in this gyroscope, so the asymmetry spring and the thermal stress, which most micromachined gyroscopes suffer from, are reduced. In order to reduce the mechanical noise, the proof masses are designed to be much larger than in most micromachined gyroscopes. The gyroscope chip is sealed at 0.001 Pa vacuum. A gyroscope sample and its read-out circuit are fabricated. The scale factor of this gyroscope is measured as 57.6 mV/（deg/sec） with a nonlinearity better than 0.12% in a measurement range of ±100 deg/sec. The short-term bias stability in 20 min is 60 deg/h.展开更多
This paper presents a comprehensive overview of the principal features of smart panels equipped with feed-forward and feedback systems for the control of the flexural response and sound transmission due respectively t...This paper presents a comprehensive overview of the principal features of smart panels equipped with feed-forward and feedback systems for the control of the flexural response and sound transmission due respectively to tonal and to stochastic broadband disturbances.The smart panels are equipped with two types of actuators:first,distributed piezoelectric actuators formed either by small piezoelectric patches or large piezoelectric films bonded on the panels and second,point actuators formed by proof-mass electromagnetic transducers.Also,the panels encompass three types of sensors:first,small capacitive microphone sensors placed in front of the panels;second,distributed piezoelectric sensors formed by large piezoelectric films bonded on the panels and third point sensors formed by miniaturized accelerometers.The proposed systems implement both single-channel and multi-channel feed-forward and feedback control architectures.The study shows that,the vibration and sound radiation control performance of both feed-forward and feedback systems critically depends on the sensor-actuator configurations.展开更多
基金supported by the National Natural Science Foundation of China (Grant No. 11002076)National Defence Pre-Research (Grant No. 51320010201)
文摘Spacecrafts free of all but gravitational forces are important in precision navigation,gravity field measurement and basic scientific research.The Inner-formation Flying System,one kind of spacecrafts free of all but gravitational forces,is used for gravitational field measurement with high precision.Restraining the interfering factors on the inner-satellite is one of the keys to gravitational field measurement.Radiometer effect and residual gas damping are both interfering forces on the inner-satellite caused by gas molecules.By analyzing the mechanism of the two forces,a coupled model for radiometer effect and residual gas damping was established,which contained the coupling term and reflected the actual force of gas molecules on the inner-satellite.The simulation results showed the coupling property of radiometer effect and residual gas damping:The actual force of gas molecules is directly proportional to the average pressure in the cavity and the largest cross-sectional area of the inner-satellite,but is inversely proportional to the square root of the average temperature in the cavity.
文摘The wave/particle duality of particles in Physics is well known. Particles have properties that uniquely characterize them from one another, such as mass, charge and spin. Charged particles have associated Electric and Magnetic fields. Also, every moving particle has a De Broglie wavelength determined by its mass and velocity. This paper shows that all of these properties of a particle can be derived from a single wave function equation for that particle. Wave functions for the Electron and the Positron are presented and principles are provided that can be used to calculate the wave functions of all the fundamental particles in Physics. Fundamental particles such as electrons and positrons are considered to be point particles in the Standard Model of Physics and are not considered to have a structure. This paper demonstrates that they do indeed have structure and that this structure extends into the space around the particle’s center (in fact, they have infinite extent), but with rapidly diminishing energy density with the distance from that center. The particles are formed from Electromagnetic standing waves, which are stable solutions to the Schrödinger and Classical wave equations. This stable structure therefore accounts for both the wave and particle nature of these particles. In fact, all of their properties such as mass, spin and electric charge, can be accounted for from this structure. These particle properties appear to originate from a single point at the center of the wave function structure, in the same sort of way that the Shell theorem of gravity causes the gravity of a body to appear to all originate from a central point. This paper represents the first two fully characterized fundamental particles, with a complete description of their structure and properties, built up from the underlying Electromagnetic waves that comprise these and all fundamental particles.
基金the National Research Foundation of Korea(NRFe2022R1F1A1073594).D.-Y Jeong thanks for the financial support from Inha University.
文摘A cantilever-structured magneto-mechano-electric(MME)generator comprising a magnetoelectric composite with a magnet proof mass is a potential candidate for powering autonomous wireless sensor networks.Recently,the concept of a magnetic flux concentrator(MFC)to enhance the output performance of the MME generator by focusing the ultralow-intensity magnetic field into the MME generator was introduced.However,the MFC-concentrated magnetic flux mostly focused on the end tip of the MME cantilever rather than at the magnet proof mass located on the cantilever beam.Considering that the torque generated by the magnet proof mass contributes more than half of the output power of an MME generator,optimizing the volume and position of the proof-mass with MFC is crucial for better performance.Furthermore,a smaller proof-mass is desirable for the long-term reliability of cantilevertype harvesters.Hence,we investigated the effect of the position and weight(volume)of the magnet proof mass with respect to the MFC on the output performance of the MME generator through finite element analysis and experiments.The MME generator with the lighter magnet proof mass at the optimized position generated a maximum power of 5.35 mW under a 10 Oe magnetic field,which was 210%of that of the MME configuration used in our previous study.Furthermore,the MME generator showed broadband characteristics around the practical frequency of 60 Hz,which could provide more freedom to design the harvester with high performance.
文摘为获得传感器的优化设计,对一种声表面波梁式加速度传感器敏感机理进行了研究。从声波波动方程出发,结合有限元分析以及微扰理论对加速度作用力作用下声表面波传播特性进行分析,以此构建梁式声表面波加速度传感器敏感机理的理论模型,特别分析了压电梁材料及几何结构、振子质量对传感响应的贡献以确定传感器优化的几何参数。为验证理论分析结果,实验研制了基于ST-X石英悬臂梁结构的差分振荡式声表面波加速度传感器,并利用精密振动台对所研制传感器性能进行评价。实验结果显示,在给定加速度测试范围内,采用ST-X石英梁并延长梁长度、降低梁厚度以及采用较大的阵子质量将有效的改善传感器检测灵敏度,在±2 g范围内加速度灵敏度可达27 k Hz/g,且实验结果很好的验证了理论模型。
基金Project supported by the National Natural Science Foundation of China (No. 11002076)the National Defence Preresearch Foundation of China (No. 51320010201)
文摘Spacecrafts with the pure gravity environment are of great significance in precision navigation, gravity field measurement for celestial bodies, and basic physics ex- periments. The radiometer effect is one of the important interfering factors on the proof mass in a purely gravitational orbit. For the gravity field measurement system based on the inner-formation flying, the relationship between the radiometer effect on the inner- satellite and the system parameters is studied by analytical and numerical methods. An approximate function of the radiometer effect suitable for the engineering computation and the correction factor are obtained. The analytic results show that the radiometer effect on the inner-satellite is proportional to the average pressure while inversely pro- portional to the average temperature in the outer-satellite cavity. The radiometer effect increases with the temperature difference in the cavity, and its minimum exists when the cavity radius increases. When the minimum of the radiometer effect arrives, the ratio of the cavity radius to the inner-satellite radius is 1.189 4. This constant is determined by the spherical cavity configuration and independent of the temperature and pressure distributions. When the ratio of the cavity radius to the inner-satellite radius is more than 10, it is believed that the cavity is large enough, the radiometer effect is approxi- mately proportional to the square of the inner-satellite radius, and the influence of the outer-satellite cavity radius on the radiometer effect can be ignored.
基金supported by the National Natural Science Foundation of China (No. 50375154)the NUDT Innovation Project for Excellent Postgraduates
文摘This paper presents a novel structure for improving the stability and the mechanical noise of micromachined gyroscopes. Only one slanted cantilever is used for suspension in this gyroscope, so the asymmetry spring and the thermal stress, which most micromachined gyroscopes suffer from, are reduced. In order to reduce the mechanical noise, the proof masses are designed to be much larger than in most micromachined gyroscopes. The gyroscope chip is sealed at 0.001 Pa vacuum. A gyroscope sample and its read-out circuit are fabricated. The scale factor of this gyroscope is measured as 57.6 mV/（deg/sec） with a nonlinearity better than 0.12% in a measurement range of ±100 deg/sec. The short-term bias stability in 20 min is 60 deg/h.
基金This work was supported by DEVISU project which was funded by the Ministero dell’Istruzione,dell’Universitàe della Ricerca,research funding programme PRIN 2017[2017ZX9X4K].
文摘This paper presents a comprehensive overview of the principal features of smart panels equipped with feed-forward and feedback systems for the control of the flexural response and sound transmission due respectively to tonal and to stochastic broadband disturbances.The smart panels are equipped with two types of actuators:first,distributed piezoelectric actuators formed either by small piezoelectric patches or large piezoelectric films bonded on the panels and second,point actuators formed by proof-mass electromagnetic transducers.Also,the panels encompass three types of sensors:first,small capacitive microphone sensors placed in front of the panels;second,distributed piezoelectric sensors formed by large piezoelectric films bonded on the panels and third point sensors formed by miniaturized accelerometers.The proposed systems implement both single-channel and multi-channel feed-forward and feedback control architectures.The study shows that,the vibration and sound radiation control performance of both feed-forward and feedback systems critically depends on the sensor-actuator configurations.
