Influence of kyphosis in ankylosing spondylitis on cardiopulmonary functions.

This paper aims at analyzing the characteristics of cardiopulmonary functions in the patients with ankylosing spondylitis (AS), and exploring the influence of global kyphosis (GK) on cardiopulmonary functions. Clinical data of 46 patients with AS and kyphosis, who had been admitted in our hospital from October 2021 to October 2022, were analyzed retrospectively. According to the to global kyphosis (GK) angle, 23 subjects were divided into Severe Group (GK > 95°), and 23 subjects were divided into in the Moderate Group (80°â€…≤ GK ≤ 95°). Cardiac structure and cardiopulmonary function parameters were compared between both groups, and the influences of GK Angle on other parameters were analyzed by Pearson or Spearman correlation analysis. The cardiac structure and function measurements in both groups were within the normal range. The pulmonary functions of both groups decreased to different extents. Correlation analysis showed that GK Angle was significantly negatively correlated with the left atrioventricular size (LAD, LVDD, LVSD) and diastolic function parameters (E/A, e'/a') in the patients with AS (P < .05); GK Angle was negatively correlated with restrictive ventilation parameters in the patients with AS (P < .05). The GK Angle of the patients with AS affects the cardiac structure and diastolic function. The larger the GK Angle is, the smaller the left and right at ventricle diameters are. In addition, GK Angle also affects the left ventricular diastolic function. GK Angle is related to the degree of pulmonary function impairment, and the larger the GK Angle is, the worse the pulmonary function it will be.

Step consistency active control method for inertial piezoelectric actuator using embedded strain gauges.

Inertial piezoelectric actuators (IPAs) are widely used in micro-nano manipulation, biomedicine, and other fields as the simple structure and excitation signal. However, the step consistency is difficult to guarantee in a large stroke range due to the limited machining accuracy of the mover and inherent roll back, which limits the practical application in these precision fields. Therefore, a step consistency active control method for IPAs is proposed based on bending hybrid motions, which uses embedded strain gauges as the force sensors to acquire the pressure between the mover and the actuator. The IPA is driven by horizontal bending motion, and the pressure can be dynamically adjusted by vertical bending motion to ensure the constant pressure and achieve a constant step. Experiments results show that the maximum standard deviation of the step is 0.41 µm under the active control of 350 Vp-p and 1 Hz driving voltage within 2 mm stroke range in 500 driving cycles, and the maximum standard deviation of the step is 1.14 µm under the non-active control with the same conditions, which show that the proposed method evidently improves the step consistency of IPA in a large stroke range.

An experiment study on temperature characteristics of a linear ultrasonic motor using longitudinal transducers.

The temperature characteristics of a T-shaped linear ultrasonic motor using longitudinal vibration transducers are reported. When the ultrasonic motor is excited by different voltages, the surface temperatures at the driving foot, PZT ceramic and end cap are tested by a thermal imager for obtaining the thermal characteristics of the motor under no-load condition. PZT ceramic shows the maximum temperature increase. Then, the variations of resonant frequencies, electromechanical coupling factors and mechanical Q-factors versus time, as well as the effect of the temperature on the resonance frequencies, electromechanical coupling factors and mechanical Q-factors, is measured and analysed under the long-term running. It is found that all the resonance frequencies and electromechanical coupling factors decrease as the increase of the temperature, as well as the mechanical Q-factors. In addition, the change of the output speed over temperature is tested and the obtained result shows the trend of decline. This work can provide useful guidelines for the design and optimization of linear ultrasonic motor operating in wide temperature range.

A novel single-mode linear piezoelectric ultrasonic motor based on asymmetric structure.

A novel single-mode linear piezoelectric ultrasonic motor based on asymmetric structure is proposed. The motor adopts the combination of the first longitudinal vibration and the asymmetric mechanical structure to produce the oblique movement on the driving foot; then, the linear output motion is obtained under the friction coupling between the driving foot and the runner. The motor is designed and its operation principle is illustrated in detail. The transient analysis is developed to verify the formed movement on the driving foot. A prototype is manufactured and its vibration characteristics are measured by a scanning laser Doppler vibrometer. An experimental system is established and the output performances of the motor are tested and discussed. The results indicate that the maximal no-load velocity of the motor is about 127.31 mm/s under the voltage of 150 Vp-p and the preload of 30 N. The maximum thrust force is about 2.8 N when the voltage and preload are 150 Vp-p and 40 N. The related works in this paper has verified the feasibility of the proposed single-mode ultrasonic motor based on asymmetric structure.

Optimization and Analysis of a U-Shaped Linear Piezoelectric Ultrasonic Motor Using Longitudinal Transducers.

A novel U-shaped piezoelectric ultrasonic motor that mainly focused on miniaturization and high power density was proposed, fabricated, and tested in this work. The longitudinal vibrations of the transducers were excited to form the elliptical movements on the driving feet. Finite element method (FEM) was used for design and analysis. The resonance frequencies of the selected vibration modes were tuned to be very close to each other with modal analysis and the movement trajectories of the driving feet were gained with transient simulation. The vibration modes and the mechanical output abilities were tested to evaluate the proposed motor further by a prototype. The maximum output speed was tested to be 416 mm/s, the maximum thrust force was 21 N, and the maximum output power was 5.453 W under frequency of 29.52 kHz and voltage of 100 Vrms. The maximum output power density of the prototype reached 7.59 W/kg, which was even greater than a previous similar motor under the exciting voltage of 200 Vrms. The proposed motor showed great potential for linear driving of large thrust force and high power density.