[1] [1] HU H J,Z X,WANG C H,et al.Stretchable ultrasonic transducer arrays for three-dimensional imaging on complex surfaces ［J］.Sci Adv,2018,4(3): 1-11.

[3] [3] TAGHADDOS E,CHARALAMBOUS H,TSAKALAKOS T,et al.Electromechanical properties of flash sintered BNT-based piezoelectric ceramic ［J］.J Eur Ceram Soc,2019,39(9):2882-2888.

[4] [4] LI P,LIU B H,SHEN B,et al.Large strain response in Bi 4Ti3O12 modified BNT-BT piezoelectric ceramics ［J］.Ceram Int,2017,43(1):1008-1013.

[5] [5] XING J,JIANG L M,ZHAO C L,et al.Potassium sodium niobate based lead-free ceramic for high-frequency ultrasound transducer applications ［J］.J Materiomics,2020,6(3):513-522.

[6] [6] LIU Y,SHEN B Z,FAN J H,et al.Dynamic hysteresis relation for guiding poling condition of high-performance KNN-based ceramics ［J］.J Eur Ceram Soc,2023,43(9):4044-4050.

[7] [7] BAH M,GIOVANNELLI F,SCHOENSTEIN F,et al.Ultrasonic transducers based on undoped lead-free(K0.5Na0.5)NbO3 ceramics ［J］.Ultrasonics,2015,63:23-30.

[8] [8] FAN F Y,ZHAO X Y,WANG F F,et al.Design and fabrication of high frequency ultrasonic transducer based on lead-free Mn-doped(K0.44Na0.56)NbO3 single crystal ［J］.Sens Actuator A:Phys,2017,267:182-186.

[9] [9] OU-YANG J,ZHU B P,ZHANG Y,et al.New KNN-based lead-free piezoelectric ceramic for high-frequency ultrasound transducer applications ［J］.Appl Phys A,2015,118(4):1177-1181.

[10] [10] CHEN R M,JIANG L M,ZHANG T F,et al.Eco-friendly highly sensitive transducers based on a new KNN-NTK-FM lead-free piezoelectric ceramic for high-frequency biomedical ultrasonic imaging applications ［J］.IEEE T Bio Med Eng,2019,66(6):1580-1587.

[11] [11] JIANG L M,YANG Y,CHEN R M,et al.Ultrasound-induced wireless energy harvesting for potential retinal electrical stimulation application ［J］.Adv Funct Mater,2019,29(1902522).

[12] [12] ZHENG T,ZHANG Y,KE Q Q,et al.High-performance potassium sodium niobate piezoceramics for ultrasonic transducer ［J］.Nano Energy,2020,70(104559).

[15] [15] VERMA K,GOEL S,SHARMA R.Influence of calcination and sintering temperature on the microstructure,dielectric,ferroelectric and piezoelectric properties of the lead-free KNN ceramics ［J］.J Mater Sci,2022,33(35):26067-85.

[16] [16] DONG Y Z,YUE Q W,CHENG D X,et al.Ultrasonic transducer with BiScO3-PbTiO3-based ceramics of operating temperature over 400 ℃ ［J］.Sens Actuator A:Phys,2022,340(113528).

[17] [17] NAKAMURA K.Ultrasonic transducers［M］.USA:Woodhead Publishing,2012:409-410.

[18] [18] CHEN Y,ZHOU D,LAM K H,et al.Endoscopic ultrasound radial array transducers fabricated with PZT tube by a rotate-and-dice method ［J］.Sens Actuator A:Phys,2013,201:357-362.

[20] [20] JADIDIAN B,HAGH N M,ALAN A W,et al.25 MHz Ultrasonic transducers with lead-free piezoceramic,1-3 PZT fiber-epoxy composite,and PVDF polymer active elements［J］.IEEE T Ultrason Ferr,2009,56(2):368-378.