Abstract: A frequency-tunable film bulk acoustic resonator and a preparation method therefor are provided. The resonator includes a substrate, an air gap, a sandwiched structure formed by electrodes and piezoelectric layers, and an electrode lead-out layer, wherein the substrate is connected to the sandwiched structure formed by the electrodes and the piezoelectric layers, and a connection face of the substrate and the sandwiched structure formed by the electrodes and the piezoelectric layers is recessed towards inside of the substrate to form the air gap; and the electrode lead-out layer is connected to the sandwiched structure formed by the electrodes and the piezoelectric layers. The sandwiched structure formed by the electrodes and the piezoelectric layers includes a bottom electrode, piezoelectric layers, intermediate electrodes, and a top electrode, wherein the electrodes and the piezoelectric layers are alternately arranged to form the sandwiched structure.

Abstract: A test device including a closeable cavity and a water flow groove with a water transmission channel existing between the water flow groove and the internal part of the cavity. The water flow groove includes a water inlet and a water outlet with the depth of the water inlet being greater than the depth of the water outlet. Simultaneously, side lead-in pipe of drain pipe and elbow pipe on side wall of water inlet pipe are consistent with height of top surface of the ceramic plate, making hydraulic pressure of tested soil sample being zero during dehydrating and soaking process capable of ensuring accuracy of test result. A necking design is applied to reduce water evaporation in the drainage pipe and lower the test errors. Side lead-in pipe is connected with drainage pipe for smoothly draining water and also can prevent air reversely flowing and entering into the base.

Abstract: A test device including a closeable cavity and a water flow groove with a water transmission channel existing between the water flow groove and the internal part of the cavity. The water flow groove includes a water inlet and a water outlet with the depth of the water inlet being greater than the depth of the water outlet. Simultaneously, side lead-in pipe of drain pipe and elbow pipe on side wall of water inlet pipe are consistent with height of top surface of the ceramic plate, making hydraulic pressure of tested soil sample being zero during dehydrating and soaking process capable of ensuring accuracy of test result. A necking design is applied to reduce water evaporation in the drainage pipe and lower the test errors. Side lead-in pipe is connected with drainage pipe for smoothly draining water and also can prevent air reversely flowing and entering into the base.