Abstract: A shear vibration-based piezoelectric composite material and a preparation method thereof are disclosed. The piezoelectric composite material includes a piezoelectric material and the passive material. The piezoelectric material includes a piezoelectric material polarized along the x-axis positive and a piezoelectric material negatively polarized along the x-axis. The piezoelectric materials in the two polarization directions are alternately arranged along the x-axis direction. The passive material includes a filling layer, a transition layer, and a planar layer. The filling layer is disposed between every two adjacent piezoelectric materials. The planar layer is located outer two surfaces perpendicular to the z-axis of the piezoelectric material. The planar layer on one side is fixedly connected to the filling layer in the odd-numbered position via the transition layer. The planar layer on the other side is fixedly connected to the filling layer in the even-numbered position via the transition layer.

Abstract: A shear vibration-based piezoelectric composite material and a preparation method thereof are disclosed. The piezoelectric composite material includes a piezoelectric material and the passive material. The piezoelectric material includes a piezoelectric material polarized along the x-axis positive and a piezoelectric material negatively polarized along the x-axis. The piezoelectric materials in the two polarization directions are alternately arranged along the x-axis direction. The passive material includes a filling layer, a transition layer, and a planar layer. The filling layer is disposed between every two adjacent piezoelectric materials. The planar layer is located outer two surfaces perpendicular to the z-axis of the piezoelectric material. The planar layer on one side is fixedly connected to the filling layer in the odd-numbered position via the transition layer. The planar layer on the other side is fixedly connected to the filling layer in the even-numbered position via the transition layer.

Abstract: A method for synchronizing a file, comprising the following steps: a step for receiving a synchronously uploaded file, dividing the content of said uploaded file into a head portion, and a rest portion and producing corresponding files which are respectively corresponding to said head portion and said rest portion by means of a server; a step for downloading said corresponding files which is corresponding to said head portion of the content of each said uploaded file to a terminal by means of said server; a step for downloading said corresponding files which is corresponding to said rest portion of the content of each said uploaded file to said terminal, and combining said corresponding files which is corresponding to said rest portion with said corresponding files which is corresponding to said head portion by means of said server.