摘要：A theoretical model and mathematical description for silicon micromachined elec- trostatic or capacitive ultrasonic imaging transducers have been developed. Ac- cording to the model the basic performance parameters of such a transducer, such as natural frequencies, eigenfunctions, resonance and anti-resonance frequencies, and the mechanical impedance of the diaphragm can be predicted from the ge- ometry of the transducer and property parameters of materials used. The paper reveals that this type of transducers has two basic operation modes, correspond- ing to the resonance of a mass-spring oscillator comprised of the diaphragm and the air cushion, and the first-order bending mode of the diaphragm itself respec- tively, and presents an optimal method for extending the bandwidth by making the two modes coupled, and thereby provides a theoretical basis for the optimal de- sign.

摘要：A compound machine tool was designed, which combined rotary ultrasonic assisted grinding, electrical discharge machining(EDM) and multi-axis milling. Experimental results indicated that its positioning accuracy was less than 5.6 μm and its repetitive positioning accuracy was less than 1.8 μm; the vibration amplitude of ultrasonic grinding system was uniform and stable, and the EDM system worked well and stably.A smooth surface of K9 optical glass component was achieved by the grinding method.

摘要：This paper presents quiet zone design using ultrasonic transducers for local active control in pure tone diffuse fields. Most of researches in local active noise control used conventional loudspeakers for the secondary sources to produce quiet zones. Recently ultrasonic transducers have been used for the secondary sources to control the plane wave in active noise control. However there is no research related to active noise control in diffuse fields using ultrasonic transducers. Therefore this study uses ultrasonic transducers for the secondary sources to control the diffuse fields. The quiet zone produced using ultrasonic transducers in single tone diffuse fields has been analyzed through simulations in this work. The results showed that quiet zones created using ultrasonic transducers were larger than those created using conventional loudspeakers. This is due to the fact that the audible sound pressure produced by the ultrasonic transducers decays slowly with the distance. Therefore the secondary field created by an ultrasonic transducer could fit the primary field better and the larger zone of quiet could be obtained using the ultrasonic transducer. Also the audible sound produced by the ultrasonic transducers is directional;therefore the sound pressure amplification outside the quiet zones was lower.

摘要：A kind of remote ultrasonic generating system is designed in this *** unit(MCU)Kinetis60and direct digital synthesizer(DDS)AD9951constitute the core section of this ultrasonic generating terminal in this system.A friendly and easy-operating host computer software is contrived to control the terminal to generate sinusoidal,rectangular and triangular waveform with variable frequency,amplitude and phase through ZigBee wireless transmission *** order to enhance the practical driving ability,this system also includes power amplifier circuit and transformer matching design,which enable the ultrasonic generating terminal to output enough power for applying to different types of ultrasonic energy *** experimental verification,the host computer can precisely and swiftly control the ultrasonic generating terminal to generate the above three waveforms with variable wave *** is used to verify the terminal output performance of this remote system.

摘要：This study aimed to explore the main factors influencing the extraction of anthocyanins from strawberry, such as solid-liquid ratio, concentration of solvent, duration of ultrasonic treatment and ultrasonic power. According to the results of sin-gle factor test, an orthogonal experiment was designed to determine the optimum extraction conditions. The effects of the four factors on anthocyanins extraction from strawberry were listed here in an decreasing order： ethanol concentration 〉 solid-liq-uid ratio〉duration of ultrasonic treatment〉ultrasonic power. And the optimal condi-tions of ultrasonic extraction of anthocyanins from strawberry were： ultrasonic treat-ment of 30 min, solid-liquid ratio of 1：15, ethanol concentration of 60% and ultra-sonic power of 300 W. Under such conditions, the content of extracted antho-cyanins was 33.247 mg/100g, which was 1.3 folds higher than that by extraction without ultrasonic treatment.

摘要：Compared to traditional rigid robots, soft robots, primarily made of deformable, or less rigid materials, have good adaptability, conformability and safety in interacting with the environment. Although soft robots have shown great potentials for extended applications and possibilities that are impossible or difficult for rigid body robots, it is of great importance for them to have the capability of controllable stiffness modulation. Stiffness modulation allows soft robots to have reversible change between the compliant, or flexible state and the rigid state. In this paper, we summarize existing principles and methods for stiffness modulation in soft robotic development and divide them into four groups based on their working principles. Acoustic-based methods have been proposed as the potential fifth group in stiffness modulation of soft robots. Initial design proposals based on the proposed acoustic method are presented, and challenges in further development are highlighted.

摘要：以棉籽油为原料,KOH为催化剂,通过超声波强化制备生物柴油(FAME)。采用四因素二次正交旋转组合设计实验。结果表明:采用超声波强化与机械搅拌反应体系相比,反应时间从40min缩短至20min,节能效果明显;得出了超声强化合成FAME的最佳工艺条件为:醇油比6.5:1,超声时间20min,占空比28%,催化剂用量0.9%,FAME的得率为97.35%,所得生物柴油各项指标基本达到欧洲EN14214和0#生物柴油标准。

摘要：Background Traditional techniques used for harvesting the pectoralis major myocutaneous （PMMC） flap have accompanying disadvantages,such as the necessity for an upper chest skin incision,the bulkiness of myocutaneous tissue at the pedicle of the flap,and the risk of total or partial necrosis of flap *** aim of this study was to develop a safe and fast method for preparing PMMC island flaps using preoperative ultrasonography for vessel *** Forty-one PMMC island flaps were used for one-stage reconstruction of head and neck defects,including 21 cases in the treatment group and 20 cases in the control *** the treatment group,ultrasonography was used to mark out the course of the thoracic branches of the thoracoacromial artery and the lower end of this artery perforating from the fascia into the muscles,as well as the largest perforating branch of the fourth or fifth internal mammary artery entering the PMMC flap.A line,from the lower end of the thoracic branch to the largest perforating branch of the fourth or fifth internal mammary artery,was drawn to determine the axis of the PMMC *** the control group,PMMC island flaps were designed according to conventional methods without using *** According to the ultrasonic marks,the distance from lower end of thoracic branch to the midpoint of the margin of the inferior clavicular was （5.1±1.2） *** time from designing to transferring the island flap was significantly shorter in the treatment group （（51.0±10.5） minutes） compared with the control group （（78.0±13.9） minutes,P 〈0.01）.The rate of partial necrosis was 4.7% （1/21） in the treatment group and 35.0% （7/20） in the control *** was one case of flap failure in the control group due to vascular injury during vascular pedicle *** Preoperative vessel detection by ultrasonography facilitates easy and safe harvesting of the true PMMC island flap.

摘要：根据功率超声振动车削的加工特点,在原有设备的基础上,改进并设计了适于镁铝合金加工的纵向超声振动车削装置,该装置由压电换能器、复合变幅杆、换能器外壳、刀具、刀具安装部分和装置安装部分组成,并对变幅杆和整个装置系统进行模态分析,得到变幅杆和整个装置系统的共振频率分别为21.611KHz和18.236KHz,分析结果符合设计要求,为进一步实验打下了基础。

摘要：应用Pro/MECHANICA软件对阶梯形变幅杆进行模态分析和修正,求出放大系数、共振频率、位移节点等重要参数,分析了变幅杆外形结构尺寸的变化对超声纵向振动性能参数的影响。