We study the effects of mechanical nonlinearity arising from large thickness-shear deformation on the transient process of an AT-cut quartz plate resonator. Mindlin＇s two-dimensional plate equation is used, from whic...We study the effects of mechanical nonlinearity arising from large thickness-shear deformation on the transient process of an AT-cut quartz plate resonator. Mindlin＇s two-dimensional plate equation is used, from which a system of first-order nonlinear differential equations governing the evolution of the vibration amplitude is obtained. Numerical solutions by the Runge-Kutta method show that in common operating conditions of quartz resonators the nonlinear effect varies from noticeable to significant. As resonators are to be made smaller and thinner in the future with about the same power requirement, nonlinear effects will become more important and need more understanding and consideration in resonator design.展开更多
Through collecting,reflecting and summarizing various opinions on the conservation of the old city in South Nanjing,this paper examines the problems that the declining historic quarters are facing amid the urban renew...Through collecting,reflecting and summarizing various opinions on the conservation of the old city in South Nanjing,this paper examines the problems that the declining historic quarters are facing amid the urban renewal process.Moreover,in combination with the existing planning practices in the old city in South Nanjing,this paper carries out a discussion on the renewal of the declining historic quarters from the perspective of values,exploration and assessment of historic resources,choice of renewal methods,and support of implementation system.展开更多
基金supported by the Program for New Century Excellent Talents in Universities(No.NCET-12-0625)the Natural Science Foundation for Distinguished Young Scholars of Jiangsu Province(No.SBK2014010134)+2 种基金the Fundamental Research Funds for Central Universities(No.NE2013101)the National Natural Science Foundation of China(No.11232007)a project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘We study the effects of mechanical nonlinearity arising from large thickness-shear deformation on the transient process of an AT-cut quartz plate resonator. Mindlin＇s two-dimensional plate equation is used, from which a system of first-order nonlinear differential equations governing the evolution of the vibration amplitude is obtained. Numerical solutions by the Runge-Kutta method show that in common operating conditions of quartz resonators the nonlinear effect varies from noticeable to significant. As resonators are to be made smaller and thinner in the future with about the same power requirement, nonlinear effects will become more important and need more understanding and consideration in resonator design.
文摘Through collecting,reflecting and summarizing various opinions on the conservation of the old city in South Nanjing,this paper examines the problems that the declining historic quarters are facing amid the urban renewal process.Moreover,in combination with the existing planning practices in the old city in South Nanjing,this paper carries out a discussion on the renewal of the declining historic quarters from the perspective of values,exploration and assessment of historic resources,choice of renewal methods,and support of implementation system.
