This comparative study acquaints the reader with some properties of the eighth and tenth new shear-horizontal surface acoustic waves (SH-SAWs) propagating along the free surface of the magnetoelectroelastic (6 mm) med...This comparative study acquaints the reader with some properties of the eighth and tenth new shear-horizontal surface acoustic waves (SH-SAWs) propagating along the free surface of the magnetoelectroelastic (6 mm) medium. These new nondispersive SH-SAWs cannot exist when the electromagnetic constant α is equal to zero. The piezoelectromagnetic SH bulk acoustic wave and the surface Bleustein-Gulyaev-Melkumyan (BGM) wave are also chosen for comparison. The main problem of this report is the demonstration of the fact that the new waves can propagate slower than the BGM wave. This problem can be very important due to the fact that among the other known SH-SAWs the BGM wave can propagate significantly slower than the corresponding SH bulk acoustic wave. Two new SH-SAWs are analytically and graphically studied in dependence on the electromagnetic constant α. For the graphical study, two (6 mm) composites are used: BaTiO3– CoFe2O4 and PZT-5H–Terfenol-D. For the second composite it is solidly demonstrated that for small values of α, the eighth new SH-SAW cannot exist and its velocity starts with zero at some small threshold value of α rapidly reaching the BGM-wave velocity. This means that a weak magnetoelectric effect can dramatically slow down the speed of either new SH-SAW. As a result, the studied new SH-SAWs can be suitable for creation of new technical devices to sense the magnetoelectric effect. For the analytical study, extreme and inflexion points were evaluated in the velocities’ dependencies on the value of the electromagnetic constant α.展开更多
设计了一种基于双通道水平剪切声表面波(SH-SAW)传感器的新型液相分析仪器,该分析仪器以数字信号处理芯片(DSP)TM S320VC 5402为微处理器,在复杂可编程逻辑器件(CPLD)EPM 7128S的基础上开发了相应的专用接口电路。系统采用流动注射分析(...设计了一种基于双通道水平剪切声表面波(SH-SAW)传感器的新型液相分析仪器,该分析仪器以数字信号处理芯片(DSP)TM S320VC 5402为微处理器,在复杂可编程逻辑器件(CPLD)EPM 7128S的基础上开发了相应的专用接口电路。系统采用流动注射分析(F IA)技术,实现各种溶液的物理特性参数的全自动分析检测。此外,通过基于PD IU SBD 12器件的U SB总线(U n iversa l Seria l Bus)的接口,分析仪器可方便地与计算机进行通讯。实验表明该分析仪器能有效地检测溶液的总盐度、白酒酒精度以及有机溶液中的水质量分数等参数指标。仪器具有灵敏度高、重复性好、检测速度快、体积小以及便携等特点,在工业生产和环境现场实时监测中有良好的应用前景。展开更多
Acoustic wave propagation in piezoelectric crystals of classes 43m and 23 is studied. The crystals Tl3VS4 and Tl3TaSe4 （43m） of the Chalcogenide family and the crystal Bi12TiO20 （23） possess strong piezoelectric e...Acoustic wave propagation in piezoelectric crystals of classes 43m and 23 is studied. The crystals Tl3VS4 and Tl3TaSe4 （43m） of the Chalcogenide family and the crystal Bi12TiO20 （23） possess strong piezoelectric effect. Because the surface Bleustein-Gulyaev waves cannot exist in piezoelectric cubic crystals, it was concluded that new solutions for shear-horizontal surface acoustic waves （SH-SAWs） are found in the monocrystals using different electrical boundary conditions such as electrically ＂short＂ and ＂open＂ free-surfaces for the unique [ 101 ] direction of wave propagation. For the crystal Tl3TaSe4 with coefficient of electromechanical coupling （CEMC） Ke^2=e^2/（C×g）-1/3, the phase velocity Vph for the new SH-SAWs can be calculated with the following formula： Vph=（Vα＋Vt）/2, where Vt is the speed of bulk SH-wave, Vt=Vt4（1＋Ke^2）^1/2, Vα=αKVt4, αK=2[Ke（1＋Ke^2）^1/2-Ke^2]^1/2, and Vt4=（C44/p）^1/2. It was found that the CEMC K2 evaluation for Tl3TaSe4 gave the value of K^2=2（Vf-Vm）/Vf-0.047 （-4.7%）, where Vf-848 m/s and Vm-828 m/s are the new-SAW velocities for the free and metallized surfaces, respectively. This high value of KZ（Tl3TaSe4） is significantly greater than K2（Tl3VS4）-3% and about five times that of K2（Bi12YiO20）.展开更多
Investigation of the propagation of the wave in SAW sensors is a basis for the research and design of the sensors. With the advance of the sensor, both the effect of environment on the surface ply and the geometry of ...Investigation of the propagation of the wave in SAW sensors is a basis for the research and design of the sensors. With the advance of the sensor, both the effect of environment on the surface ply and the geometry of waveguide are complicated. To consider the complication, a model with gradient surface ply and multilayer waveguide of SH wave propagation in sensor is proposed. The equation of wave velocity is derived by a transfer matrix method. Through the equation, the function of wave velocity increment via the change of parameters in the surface ply is obtained. The effect of the inhomogeneity on the function is also studied. Finally, some influencing factors of the behavior of the sensor are discussed.展开更多
文摘This comparative study acquaints the reader with some properties of the eighth and tenth new shear-horizontal surface acoustic waves (SH-SAWs) propagating along the free surface of the magnetoelectroelastic (6 mm) medium. These new nondispersive SH-SAWs cannot exist when the electromagnetic constant α is equal to zero. The piezoelectromagnetic SH bulk acoustic wave and the surface Bleustein-Gulyaev-Melkumyan (BGM) wave are also chosen for comparison. The main problem of this report is the demonstration of the fact that the new waves can propagate slower than the BGM wave. This problem can be very important due to the fact that among the other known SH-SAWs the BGM wave can propagate significantly slower than the corresponding SH bulk acoustic wave. Two new SH-SAWs are analytically and graphically studied in dependence on the electromagnetic constant α. For the graphical study, two (6 mm) composites are used: BaTiO3– CoFe2O4 and PZT-5H–Terfenol-D. For the second composite it is solidly demonstrated that for small values of α, the eighth new SH-SAW cannot exist and its velocity starts with zero at some small threshold value of α rapidly reaching the BGM-wave velocity. This means that a weak magnetoelectric effect can dramatically slow down the speed of either new SH-SAW. As a result, the studied new SH-SAWs can be suitable for creation of new technical devices to sense the magnetoelectric effect. For the analytical study, extreme and inflexion points were evaluated in the velocities’ dependencies on the value of the electromagnetic constant α.
文摘设计了一种基于双通道水平剪切声表面波(SH-SAW)传感器的新型液相分析仪器,该分析仪器以数字信号处理芯片(DSP)TM S320VC 5402为微处理器,在复杂可编程逻辑器件(CPLD)EPM 7128S的基础上开发了相应的专用接口电路。系统采用流动注射分析(F IA)技术,实现各种溶液的物理特性参数的全自动分析检测。此外,通过基于PD IU SBD 12器件的U SB总线(U n iversa l Seria l Bus)的接口,分析仪器可方便地与计算机进行通讯。实验表明该分析仪器能有效地检测溶液的总盐度、白酒酒精度以及有机溶液中的水质量分数等参数指标。仪器具有灵敏度高、重复性好、检测速度快、体积小以及便携等特点,在工业生产和环境现场实时监测中有良好的应用前景。
文摘Acoustic wave propagation in piezoelectric crystals of classes 43m and 23 is studied. The crystals Tl3VS4 and Tl3TaSe4 （43m） of the Chalcogenide family and the crystal Bi12TiO20 （23） possess strong piezoelectric effect. Because the surface Bleustein-Gulyaev waves cannot exist in piezoelectric cubic crystals, it was concluded that new solutions for shear-horizontal surface acoustic waves （SH-SAWs） are found in the monocrystals using different electrical boundary conditions such as electrically ＂short＂ and ＂open＂ free-surfaces for the unique [ 101 ] direction of wave propagation. For the crystal Tl3TaSe4 with coefficient of electromechanical coupling （CEMC） Ke^2=e^2/（C×g）-1/3, the phase velocity Vph for the new SH-SAWs can be calculated with the following formula： Vph=（Vα＋Vt）/2, where Vt is the speed of bulk SH-wave, Vt=Vt4（1＋Ke^2）^1/2, Vα=αKVt4, αK=2[Ke（1＋Ke^2）^1/2-Ke^2]^1/2, and Vt4=（C44/p）^1/2. It was found that the CEMC K2 evaluation for Tl3TaSe4 gave the value of K^2=2（Vf-Vm）/Vf-0.047 （-4.7%）, where Vf-848 m/s and Vm-828 m/s are the new-SAW velocities for the free and metallized surfaces, respectively. This high value of KZ（Tl3TaSe4） is significantly greater than K2（Tl3VS4）-3% and about five times that of K2（Bi12YiO20）.
基金This study was supported by the National Natural Science Foundation of China (No. 59635140)the Doctoral Education Foundation of the Ministry of Education of ChinaAeronautics Foundation of China.
文摘Investigation of the propagation of the wave in SAW sensors is a basis for the research and design of the sensors. With the advance of the sensor, both the effect of environment on the surface ply and the geometry of waveguide are complicated. To consider the complication, a model with gradient surface ply and multilayer waveguide of SH wave propagation in sensor is proposed. The equation of wave velocity is derived by a transfer matrix method. Through the equation, the function of wave velocity increment via the change of parameters in the surface ply is obtained. The effect of the inhomogeneity on the function is also studied. Finally, some influencing factors of the behavior of the sensor are discussed.
