对于声表面波而言温度特性是非常重要的一个指标.而石英基板在表面波器件中应用广泛.当环境温度改变时,基板尺寸会发生变化,弹性系数和压电系数值也会发生变化,在考虑这些变化的基础上就可以考察声表面波器件的温度特性.这是通常的方法...对于声表面波而言温度特性是非常重要的一个指标.而石英基板在表面波器件中应用广泛.当环境温度改变时,基板尺寸会发生变化,弹性系数和压电系数值也会发生变化,在考虑这些变化的基础上就可以考察声表面波器件的温度特性.这是通常的方法.但是,弹性系数和压电系数的温度系数其实参考了随温度变化的中间状态,而并非定义弹性系数和压电系数的参考温度时的状态.在某些场合下,由于温度变化会产生一个非均匀分布的形变,比如带电极的体波谐振器以及多层声表面波基板,上述方法就会失效.在其它的一些场合,如力和加速度传感器的情况,初始形变可能是由于外力或者加速度造成的.为了得到这些在形变媒质上小振幅声波的传播特性,一些学者从非线性方程发展出一套理论.按照这种理论,可以得到参考同一参考状态的弹性常数以及它们的温度系数.P.C.Y.Lee和Y.K.Yong[Journal of Applied Physics,1986,60:.2327]给出了一套完整的热形变媒质中小振幅振动的理论,并推导出了石英晶体弹性常数的一阶、二阶和三阶温度系数.他们成功地考察了石英体波谐振器的温度特性.在本文中,我们对LeeandYong的理论加以推广,引入了压电性.这样,该方法也可以用来分析具有强压电性的基板了.我们分析了石英基板上声表面波的温度特性.文中给出了ST-切,MD-切和K-切石英基板的计算结果.计算结果证明了该方法的有效性.当然新方法比传统的方法要复杂的多.因为该方法在理论上具有一般性,如果先计算出器件结构中初始应变的分布,它就可以顺利地来分析多层基板上声表面波或者是一些传感器的工作特性.展开更多
Silver nanostructure compact aggregates on the surface of quartz glass substrates were synthesized by small gold seeds with the assistance of poly vinypyrrolidone (PVP) and irradiation of fluorescent lamp. The formati...Silver nanostructure compact aggregates on the surface of quartz glass substrates were synthesized by small gold seeds with the assistance of poly vinypyrrolidone (PVP) and irradiation of fluorescent lamp. The formation mechanism of silver nanostructure was proposed. The results show that both the PVP and the light irradiation are the keys to in-situ growth of silver nanostructure on quartz glass substrates. The silver nanostructure of the substrates which finally grow up to 150 nm after 20 h irradiation exhibits irregular shape, and some of nanoparticles stack to form bilayer. A new broad band appears in the absorption spectra of the substrates due to the interparticle dipole?dipole coupling of surface plasmon resonance response of the triangular silver nanoplate particles, which red shifts 600?800 nm as the particles grow up. The substrates have an emission band centered at 400 nm on their fluorescence spectra, and the fluorescence intensity shrinks as the average size of the silver nanostructure increases. The strongest SERS signal of SERS-active substrate is fabricated after 16 h.展开更多
基金National Natural Science Foundation of China(10974094)
文摘对于声表面波而言温度特性是非常重要的一个指标.而石英基板在表面波器件中应用广泛.当环境温度改变时,基板尺寸会发生变化,弹性系数和压电系数值也会发生变化,在考虑这些变化的基础上就可以考察声表面波器件的温度特性.这是通常的方法.但是,弹性系数和压电系数的温度系数其实参考了随温度变化的中间状态,而并非定义弹性系数和压电系数的参考温度时的状态.在某些场合下,由于温度变化会产生一个非均匀分布的形变,比如带电极的体波谐振器以及多层声表面波基板,上述方法就会失效.在其它的一些场合,如力和加速度传感器的情况,初始形变可能是由于外力或者加速度造成的.为了得到这些在形变媒质上小振幅声波的传播特性,一些学者从非线性方程发展出一套理论.按照这种理论,可以得到参考同一参考状态的弹性常数以及它们的温度系数.P.C.Y.Lee和Y.K.Yong[Journal of Applied Physics,1986,60:.2327]给出了一套完整的热形变媒质中小振幅振动的理论,并推导出了石英晶体弹性常数的一阶、二阶和三阶温度系数.他们成功地考察了石英体波谐振器的温度特性.在本文中,我们对LeeandYong的理论加以推广,引入了压电性.这样,该方法也可以用来分析具有强压电性的基板了.我们分析了石英基板上声表面波的温度特性.文中给出了ST-切,MD-切和K-切石英基板的计算结果.计算结果证明了该方法的有效性.当然新方法比传统的方法要复杂的多.因为该方法在理论上具有一般性,如果先计算出器件结构中初始应变的分布,它就可以顺利地来分析多层基板上声表面波或者是一些传感器的工作特性.
基金Projects(10804101,60908023)supported by the National Natural Science Foundation of ChinaProject(2007CB815102)supported by the National Basic Research Program of ChinaProject(2007B08007)supported by the Science and Technology Development Foundation of Chinese Academy of Engineering Physics
文摘Silver nanostructure compact aggregates on the surface of quartz glass substrates were synthesized by small gold seeds with the assistance of poly vinypyrrolidone (PVP) and irradiation of fluorescent lamp. The formation mechanism of silver nanostructure was proposed. The results show that both the PVP and the light irradiation are the keys to in-situ growth of silver nanostructure on quartz glass substrates. The silver nanostructure of the substrates which finally grow up to 150 nm after 20 h irradiation exhibits irregular shape, and some of nanoparticles stack to form bilayer. A new broad band appears in the absorption spectra of the substrates due to the interparticle dipole?dipole coupling of surface plasmon resonance response of the triangular silver nanoplate particles, which red shifts 600?800 nm as the particles grow up. The substrates have an emission band centered at 400 nm on their fluorescence spectra, and the fluorescence intensity shrinks as the average size of the silver nanostructure increases. The strongest SERS signal of SERS-active substrate is fabricated after 16 h.