Based on a BoxBehnken design,response surface methodology was used to optimize the effects of processing parameters of extraction from Scutellaria barbata on total alkaloids yield. Three independent variables such as extraction time (X1), liquid-solid ratio (X2) and ultrasonic frequency (X3) were study. The P-value indicated that both extraction time (X1) and ultrasonic frequency (X3) had signi...

Modulus of elasticity is one of the important parameters of construction materials, which considerably influence their deformation properties and which can also be determined by means of non-destructive test methods like ultrasonic pulse method. However, measurement results of ultrasonic pulse methods are influenced by various factors, one of which is the natural frequency of the transducers. T...

In this study a novel servo speed control system for travelling-wave ultrasonic motor (TWUSM) has been presented. A drive system has been built based on two-phase high-frequency inverter using mechanical resonant frequency of the ultrasonic motor. The TMS320F243 digital signal processor (DSP) is adapted to ultrasonic motor drive system. The speed control of ultrasonic motor has been implemented...

The earlier report that the frequency dependence of ultrasonic absorption of mammalian testis memicked a single relaxation process is explained as an effect of ultrasonic beam width upon the transient thermoelectric technique. More detailed measurements show that the frequency dependence of the ultrasonic absorption in testis is much the same as the attenuation in other soft tissues, viz., a pr...

A digitally controlled drive system was implemented in this study to control the speed and direction of a travelling-wave ultrasonic motor. The drive system, based on a 2-phase voltage-fed high-frequency serial-resonant inverter, uses the mechanical resonant frequency of an ultrasonic motor. A TMS320F243 digital signal processor was used to control an ultrasonic motor drive system. The speed co...

In this article, embedded ultrasonic sensors were prepared using 1–3-type piezoelectric composite and piezoelectric ceramic as the piezoelectric elements, respectively. The frequency bandwidth of the novel embedded ultrasonic sensors was investigated. To obtain the relationship between the receiving ultrasonic velocity and compressive strength, as well as their response signals to crack damage,...

A novel frequency-swept ultrasound-modulated optical tomography technique was developed to image scattering media. A frequency-swept ultrasonic wave was used to modulate the laser light passing through a scattering medium. The modulated light was received by an optical detector and was heterodyned with a reference frequency sweep. The heterodyned signal was recorded in the time domain and was t...