[Retracted] Application of Internet of Things Technology in the Construction of Bored Pile Foundation in a High Altitude Environment

Table 3

Sonar-receiving transducer parameters.

Model	Resonant frequency/kHz	Usage frequency	Capacitance	Sensitivity/dB
–5–2	30 ± 2	100 Hz～10 kHz	1 600 pF ± 20％	−190
Minimum impedance	Operating temperature/°C	Pressure/MPa	Shell material	Use
400 Ω ± 20％	−40～+80	1.0	Can be used in weak acid and weak alkali environment	Sonar monitoring