Mdo3102

As shown in Fig. 1, the experimental equipment includes: arbitrary function generator (RIGOL DG1062Z), signal amplifier (PINTECH HA-520), oscilloscope (Tektronix MDO3102), PZT patch and the sample of coal with size of 100 mm × 50 mm × 50 mm. As shown in Fig. 2, the width of the crack was about 2 mm in the middle of the sample, and the depth were 0 mm, 5 mm, 10 mm, 20 mm and 40 mm respectively.Figure 1

Coal crack monitoring system based on PZT sensor.

Figure 2

The coal samples tested.

The materials and devices were characterized using an optical microscope (Nikon ECLIPSE LV100ND), aberration-corrected TEM (Thermo Scientific^TM, Titan Cube Themis G2), with the operating voltage at 300 kV and Super-X detector system for Energy-Dispersive X-ray spectrometry (EDX) mappings, and an X-ray photoelectron spectroscopy analyser (Thermo VG Scientific ESCALAB250). The electrical and optoelectronic performance was measured using a semiconductor analyser (Agilent B1500A), a probe station (Cascade M150) and a laser diode controller (Thorlabs ITC4001, with laser excitations of 405 and 638 nm) in a dark room at room temperature; 405 nm of light was generated using a Thorlabs ITC4001 unit, and a current amplifier (Model SR570) and an oscilloscope (Tektronix MDO3102) were used to provide a gate voltage to characterize the programming and erasing performance. The noise was measured using a noise-measurement system (Fs Pro, 100 kHz bandwidth).