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Electronic scanning of two-dimensional (2-D) arrays and mechanical or freehand scanning of one-dimensional (1-D) arrays have been mostly utilized for conventional three-dimensional (3-D) ultrasound (US) imaging. However, the development of 2-D arrays and the hardware systems are complicated and expensive, while freehand systems with positioning sensors and mechanical systems are mostly bulky. This article represents a novel scanning strategy for achieving high-quality 3-D US imaging with a high-frequency single-element transducer. A 42-MHz US transducer with a compact structure was designed and fabricated, which was excited in the 2-D vibration by a tubular piezoelectric actuator. A dedicated imaging system was set up and both B-mode and 3-D US imaging of a custom wire phantom have been carried out to evaluate the performance of the proposed transducer. Compared to the results obtained with the motorized linear translation stage, the reconstructed images obtained by the proposed resonance scanning method are accurate, demonstrating the feasibility of 3-D US imaging with a vibrating single-element US transducer.

In-plane bending traveling wave ultrasonic motors (USM), which are compact in structure and flexible in design, have been widely applied in biological engineering, optical engineering, and aerospace engineering. However, the high driving voltage and complicated driving circuit of this kind of USM restrict their further miniaturization and electromechanical integration in these applications and bring some potential safety hazards. To solve this problem, a low-voltage-driving traveling wave USM incorporating cofired multilayer piezoelectric ceramics was proposed in this work. Four cofired piezoelectric ceramics were strategically designed to excite two orthogonal third-order in-plane bending modes with the same frequency of the USM. The principles of traveling wave synthesis and low-voltage-driving of the USM were deduced, and the stator dynamic design and transient dynamic simulation were carried out by finite-element method. The microproperties of cofired piezoelectric multilayer ceramics, the vibration characteristics of the stator, and the mechanical output performance of the USM were tested by experiments. The results indicated that the motor can work as low as 5 [Formula: see text]. A long stroke with a maximum forward and reverse rotational speeds of 187.7 and 176.6 r/min were obtained, respectively, and a maximum stalling torque of 4.8 mN · m at 47.3 kHz under 15 [Formula: see text] was achieved. The results showed that the proposed USM is small, low in driving voltage, and high in torque output, which has promising applications in aerospace, biomedicine, and other fields that require a lightweight and integration of driving devices.

Ultrasound imaging commonly uses mechanical or electronic scanning methods. However, the mechanical scanning systems are bulky and susceptible to Electromagnetic Interference, while electronic scanning systems are complex and expensive. A more affordable and compact solution for high frequency preclinical and clinical imaging is single-element transducer based ultrasound imaging. This method offers high spatial resolution with low cost and low complexity. In this study, a novel single-element high frequency ultrasound imaging scanner was introduced. The scanner is based on piezoelectric bimorph drive and designed to be low-cost, compact, and handheld. Tungsten wire phantom imaging was performed on a dedicated ultrasound imaging system, and the obtained results were analyzed and compared. The results demonstrate that piezoelectric bimorph drive allows for high frequency imaging with a scanning speed of up to 208 frames per second. The image quality was higher than that of electromagnetic motor drive. The versatility of the ultrasound imaging system makes it suitable for preclinical and clinical applications, including small animal imaging, ophthalmic imaging, skin imaging, and intraoperative ultrasound imaging.

Existing three-dimensional (3D) intravascular ultrasound (IVUS) systems that combine two electromagnetic (EM) motors to drive catheters are bulky and require considerable efforts to eliminate EM interference (EMI). Herein, we propose a new scanning method to realize 3D IVUS imaging using a helical ultrasonic motor to overcome the aforementioned issues. The ultrasonic motor with compact dimensions (7-mm outer diameter and 30-mm longitudinal length), lightweight (20.5 g), and free of EMI exhibits great application potential in mobile imaging devices. In particular, it can simultaneously perform rotary and linear motions, facilitating precise 3D scanning of an imaging catheter. Experimental results show that the signal-to-noise ratio (SNR) of raw images obtained using the ultrasonic motor is 5.3 dB better than that of an EM motor. Moreover, the proposed imaging device exhibits the maximum rotary speed of 12.3 revolutions per second and the positioning accuracy of 2.6 μm at a driving voltage of 240 Vp-p. 3D wire phantom imaging and 3D tube phantom imaging are performed to evaluate the performance of the imaging device. Finally, the in vitro imaging of a porcine coronary artery demonstrates that the layered architecture of the vessel can be precisely identified while significantly increasing the SNR of the raw images.

Intravascular ultrasound (IVUS) is emerging as a crucial tool for detecting coronary artery disease. However, the proximal scanning method brought problems of non-uniform rotation distortion and EM interference in the IVUS system to a head. In this work, a distal rotary ultrasonic micro-motor with ingenious pre-pressure applied is developed for IVUS application. The micro-motor is compact without additional pre-pressure devices, fast responding, and is free of EM interference. Moreover, it enables excellent integration into the catheter for stable rotational scanning. The proposed motor exhibits the maximum rotary speed of 31.5 revolutions per second at a driving voltage of 160 V p-p . Image results demonstrate that the distal ultrasonic micro-motor is a promising actuator for precise IVUS scanning in complex vascular environments.

Piezoelectric actuators have a wide application prospect in the micro-positioning rotary stage because of their advantages such as high energy density, fast response, power off self-locking, and anti-electromagnetic interference. In this paper, the characteristics of the compact structure of the bending mode and the low voltage of the multi-layer piezoelectric ceramic are combined to design a piezoelectric and micro positioning rotary stage that can be miniated and integrated, In the method, resonant modal was firstly analyzed with finite element method using the commercial software ANSYS. Reflectivity can be obtained with the resonant modal analysis. Simultaneously, the rotating stage is set up to measure the speed. The results demonstrate that the rotary stage starts at $5 \mathrm{V}_{p-p}$ and, speeds up to 187rpm at 20Vp-p. Moreover, the piezoelectric rotating stage can realize the miniaturization and integration of the device, and has a broad prospect in the fields such as aviation, aerospace, and biomedical that need to be lightweight, miniaturized, and safe.

In this paper, a tunable aperture driven by a single-phase piezoelectric motor is presented. The piezoelectric motor is composed of piezoelectric ceramic and carbon fiber layer. The influence of fiber orientation on the mechanical characteristics of the motor is analyzed by finite element method. The prototype of the aperture is manufactured and tested. The results show that the opening and closing durations of the aperture are 89 ms and 92.4 ms, respectively, for a rotation range of 90°, under a driving voltage of 150V. The minimum angular resolution can reach $4^{*}$10-5 radian.

To realize an effective rotary drive in a narrow interventional medical system, an ultrasonic micromotor using a coil spring is proposed, fabricated, and tested. The proposed motor operates in a first-order bending vibration mode and has a short ineffective section, ensuring sufficient output energy efficiency to enable the rotational motion. Experimental results show that the motor can afford sufficient energy efficiency with vibration frequencies of 52.81 and 52.56 kHz, respectively. The pre-pressure of the motor can be linearly changed with the spring rotor stretching, and no additional pre-pressure mechanism is required to reduce the ineffective section of the motor. Moreover, a maximum speed of 17.8 revolutions/s is achieved with a pre-pressure of 0.6 N. This novel motor holds great promise for numerous potential applications in interventional medical systems.

Design thinking is a thinking tool, process, and method to guide creative activities. This paper makes a comparative research on STEAM education in America, phenomenon-based learning in Finnish, Design and Technology Course in England, and K-12 design thinking education in China by literature research and case study, and summarizes the current situation of design thinking education in K-12 around the world. This work aims to analyze the present difficulties and then propose the ways to promote K-12 design thinking education in China. We conclude that, as for K-12 design thinking education in China, some progress has been made in organizational form, project theme and activity process, but there are still many difficulties. To further promote K-12 design thinking education in China with a high quality, it is necessary to use service design methodology to coordinate all stakeholders and integrate the social resources.

In this study, a resonant type piezoelectric vibrator for driving a flexible body is proposed and its driving principle is discussed. The flexible body driven in this article is rigid in the longitudinal direction and flexible in the transverse direction, such as in metal straps and metal wires. The exciting signals used in the piezoelectric transducer in the horizontal and vertical directions are both sinusoidal signals, possessing a phase shift of π/2. Two third-order orthogonal bending in-plane modes of the same frequency were effectively excited, and an elliptic motion formed on the end plane of the vibrator toothed structure. A flexible body was then effectively driven by friction under a certain amount of tension. The proposed vibrator was designed using the finite element method, and the flexible drive models were established, while the output force in the contact friction was analyzed. The vibration characteristics of the vibrator were tested in order to obtain the resonance frequencies and responses. An experimental system was then established to test the mechanical output characteristics. The results demonstrate that the difference in thickness, tension force, and surface roughness between the flexible bodies confer great influence on driving. With a thickness of 0.01 mm, 0.02 mm, and 0.03 mm, the flexible metal strap velocity was found to be 24 mm/s, 43.64 mm/s, and 10.43 mm/s under the corresponding proper tension, smooth surface, and voltage of 200Vp-p, respectively.

This work presents a laminated piezoelectric (PZT) motor to achieve high force density, high strength, and compact structure. The oscillator consists of vibration units and a driving foot. Each of the vibration units is formed by symmetrically bonding two PZT ceramics on a carbon fiber-reinforced plastic (CFRP) layer to improve its strength. The oscillator works in hybrid mode of the first longitudinal vibration (L1) and second bending vibration (B2). The finite-element method is adopted to tune the resonance frequencies of the two modes, and the vibration characteristics are experimentally analyzed. The strength test shows that the presence of the CFRP layer can increase the overall strength of the oscillator by 28% compared with a pure PZT motor. To evaluate the performance, the load characteristics of the fabricated prototype (with a size of 39 × 10 × 4.6 mm3 and weight of 10.6 g) are tested on a designed testbed. The single-phase driving method is used to drive the motor, and the best performance is obtained at the B2-mode frequency. The maximum thrust force, no-load speed, and output power reach 17 N, 335 mm s−1, and 775 mW, respectively, at a drive voltage of 100 Vp. Meanwhile, a thrust density of 1604 N kg−1 and an output power density of 73.11 W kg−1 are achieved. The thrust density is much higher than that of the other motors that operate in the same modes.

Owing to characteristics of single-step fabrication and rapid prototyping, 3D printing have potential applications in processing piezoelectric motors with complex structures. In this paper, a 3D printed resin-based bimodal piezoelectric motor is proposed. Four slots of the motor are designed to reduce the influence of large damping caused by polymer’s viscoelastic and enhance mechanical properties. Considering the viscoelasticity and internal structure of the stator, a dynamic model based on the proposed motor is developed. Furthermore, parameters of these slots are optimized using the Taguchi method. Prototypes are fabricated and experimentally investigated. The results demonstrate that the first longitudinal mode and the second bending mode are 17 765 Hz and 18 006 Hz respectively, which are consistent with the analytical model results. Under the voltage of 300 Vpp, the maximum no-load speed and maximum driving load of the slotted motor are 200 r min−1 and 20 g with a speed of 6 r min−1, respectively. Compared with the motor without slots, the speed and load capacity are increased by 25% and 33%. Therefore, the motor with slots exhibits better mechanical output performance.