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This paper explores the superposition of ultrasonic vibration on vertical rotating augers in a variety of granular media. Ultrasonic vibration is known to facilitate direct penetration of granular media, and it is anticipated that any related reduction in the torque requirements of a rotating system might improve augering performance. Experimental results suggest that, compared to the non-ultrasonic scenario, ultrasonically assisted augering significantly promotes the flow of granular media, while moderately reducing the torque required to operate the device. Furthermore, it was discovered that particle size, helix angle, and auger speed all affect the performance of the auger in different ways as the ultrasonic amplitude is adjusted.

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.

Some limitations exist classroom learning assessment in the basic education (K12) stage: the role of diagnostic assessment and formative assessment is weakened, and the measurement of students' cognitive thinking ability is neglected. Firstly, this study clarifies the selected topic index of classroom assessment based on the SOLO classification theory, and constructs the classroom learning assessment model supported by the mobile intelligent terminal. Then, the study designs the mobile teaching tool to promote the implementation of classroom learning assessment, and carries on the system function test and the teaching practice. Finally, the study iterates and optimizes the classroom learning assessment model and prototype system based on the effective feedback from teachers and students. The results demonstrate that the combination of the SOLO classification theory and mobile teaching tools to implement classroom learning assessment can maximum the advantages of diversified assessment and promote learning through assessment.

Polymers have attracted enormous attention due to their characteristics of low density and high energy density for potential applications in low weight piezoelectric motors. However, the viscosity of polymers presents a challenge to match two resonance frequencies of the longitudinal and bending modes of the bimodal piezoelectric motor. In this paper, polyphenylene sulfide (PPS)-based bimodal piezoelectric motor is researched. Concerning the viscoelasticity of PPS, the electromechanical coupling analytical model is established to describe the dynamics of the PPS-based motor by using the Kelvin-Voigt viscoelastic model. Based on the proposed model, the Taguchi method is adopted to match the resonance frequencies of the longitudinal and bending vibration. A PPS-based prototype motor is fabricated with optimized parameters. The frequency response characteristics, displacement response and electromechanical coupling coefficients are computed and compared to the finite element method and experimental results to validate the effectiveness of the model. The comparisons show that the proposed model is valid. The performance test demonstrates that the PPS-based motor can yield the maximal torque of 2 mNm with the stator weight of 5.4 g. Compared with the same volume of phosphor bronze material, 75% of weight reduction can be achieved.

In this study, a large thrust linear ultrasonic motor using an L-shaped stator is described. The stator is constructed by two mutually perpendicular rectangular plate vibrators, one of which is mounted in parallel with the slider to make the motor structure to be more compact. The symmetric and antisymmetric modes of the stator based on the first order bending vibration of two vibrators are adopted, in which each resonance mode is assigned to drive the slider in one direction. The placement of piezoelectric ceramics in a stator could be determined by finite element analysis, and the influence of slots in the head block on the vibration amplitudes of driving foot was studied as well. Three types of prototypes (non-slotted, dual-slot, and single-slot) were fabricated and experimentally investigated. Experimental results demonstrated that the prototype with one slot exhibited the best mechanical output performance. The maximum loads under the excitation of symmetric mode and antisymmetric mode were 65 and 90 N, respectively.

Several algorithms for association rules are discussed which are AIS algorithm, SETM algorithm, Apriori algorithm etc. Their strengths and weaknesses are investigated. Their performance are compared and analyzed. Among all the algorithms, the most inefficient one is SETM algorithm but it is the most convenient one to combine DBMS.