我国超声波疗法实验研究和临床应用的近期进展

本文通过对第四届全国超声治疗学术会议（１９９７年１０月１７－２１日于南京）论文的综合介绍,显示我国超声波疗法在实验研究与临床应用方面所取得的成就。     

超声药物透入疗法的临床应用进展

本文介绍了超声药物透入疗法的临床应用进展,简要回顾了其发展历程,讨论与评价此种疗法的临床意义,提出了存在不足与今后的发展。     

我国超声波疗法的研究与应用进展

自1939年将超声波应用于治疗某些关节痛、神经痛之后,随着时间的进展,其应用范围逐渐扩大.我国超声波疗法是解放后才开始研究与应用的.随着医疗卫生事业的发展,超声波疗法的应用也在不断发展,在长期的临床实践中积累了较丰富的经验.为了有利于超声波疗法的迅速发展,现将我国超声波疗法的进展情况综述如下.     

近五年来我国超声波疗法的应用与研究进展

我国超声波疗法在临床应用与研究方面不断取得进展.近5年来超声波疗法在原有础上,又有新的进展.     

我国超声波疗法临床应用的近期进展

通过对第五届全国超声波治疗学术会议（2000年12月1－5日于重庆）论文的综合介绍,本文报道我国超声波疗法临床应用方面近期取得的成就。     

我国超声波疗法的新进展

本文通过对第二届全国超声治疗学术会议论文的综合介绍，展示了我国超声波治疗方面的近期实验研究工作：不同频率超声波的透入、低频超声对小分子通过半透膜的影响、超声波治疗实验性家犬脑出血的疗效、颅骨对超声波的吸收率、超声波对组织硬结作用的动物实验、超声波对细菌的作用等．文章还报道了临床应用方面所取得的新进展．     

我国超声波疗法的新进展

超声波疗法是一种有效的治疗方法,临床应用广泛。我国超声波疗法,在治疗脑血管疾病所致偏瘫、坐骨神经痛、支气管炎、冠心病、颈肩腰腿软组织疼痛、关节、软组织损伤、肩关节周围炎、上尿路结石、中心性视网膜炎、带状疱疹、手足部癣、神经性皮炎、急慢性上颌窦炎等病的基础上,近年来又取得进展,予以综述与评论。     

超声波治疗脑血管病的应用进展

本文介绍了应用超声波治疗脑血管病的应用情况，并对其临床意义进行评估。     

超声波马达的应用

超声马达具有诸多优良特性,它已经在很多领域得到了广泛的应用。本文介绍了超声马达的应用现状和发展前景。     

Recent advances in sonodynamic approach to cancer therapy

Chemical agents such as porphyrins were found to be activated by ultrasound, producing significant antitumor effects. Hematoporphyrin (Hp) enhanced ultrasonically induced damage on sarcoma cells and shown a synergistic inhibitory effect on the tumor growth in combination with ultrasound at 2 MHz. Recently, other types of porphyrins such as protoporphyrin were also found to have such sonodynamic activities. Furthermore, it was found that sonochemical reactions can be greatly accelerated by superimposing the second harmonic onto the fundamental. The highest rate of iodine release from aqueous iodide was obtained at an acoustic intensity ratio between 1 MHz and 2 MHz of 1:1 while either one of the frequency components alone could not induce significant iodine release at the same total acoustic intensity. Second-harmonic superimposition in combination with sonodynamically active antitumor agents may have the potential for selective tumor treatment.     

Effect of ultrasonic frequency on size distributions of nanosized mist generated by ultrasonic atomization

Ultrasonic atomization is used to produce fine liquid mists with diameter ranges below 100 nm. We investigated the effect of the frequency on the size distribution of ultrasonic mist. A bimodal distribution was obtained for the mist generated by ultrasonic atomization with a wide-range particle spectrometer. The peak diameter decreased with increasing frequency, and the number concentration of the mist increased in the smaller range. We determined the relation between the size distribution of the mist and the ultrasonic frequency, and we proposed a generation mechanism for the ultrasonic nanosized mist based on the amount of water vapor around the liquid column. Increasing the power intensity and density by changing the surface diameter of the ultrasonic oscillator affected the number concentration and size distribution of the nanosized mist. Using this technique, the diameter of the mist can be controlled by changing the frequency of the ultrasonic transducer.     

Recent advances of ultrasonic testing of cement based materials at early ages

To summarize some of the most important findings in the field of ultrasonic (US) testing of early age hydration and formation of structure of different cement based materials (CBMs), a review of literature with focus on US P-wave transmission and S-wave reflection methods is presented in this paper. The review shows a great ability of both US techniques to observe setting phenomena and to determine different milestones during the early age formation of CBM’s microstructure. Clear physical basis, high accuracy, and non-destructive nature of the method indicate that US methods could become standardized in the near future.     

Resonance tracking and vibration stablilization for high power ultrasonic transducers

Resonant frequency shift and electrical impedance variation are common phenomena in the application of high power ultrasonic transducers, e.g. in focused ultrasound surgery and in cutting. They result in low power efficiency and unstable vibration amplitude. To solve this problem, a driving and measurement system has been developed to track the resonance of high power transducers and to stabilise their vibration velocity. This has the ability to monitor the operating and performance parameters of the ultrasonic transducers in real time. The configuration of the system, with its control algorithm implemented in LabVIEW (National Instruments, Newbury, UK), ensures flexibility to suit different transducers and load conditions. In addition, with different programs, it can be utilised as a high power impedance analyser or an instantaneous electrical power measurement system for frequencies in the MHz range. The effectiveness of this system has been demonstrated in detailed studies. With it, high transducer performance at high power can be achieved and monitored in real time.     

超声滚压中的空化现象*

在超声滚压加工中引入切削液后可能会产生空化现象,由此产生的微射流和冲击波对超声表面强化将有积极作用。为研究超声滚压加工中空化现象是否存在及空化效应在超声滚压中的作用,本文首先分析了超声滚压中的空化阈值,然后进行了染色法试验和超声滚压后试样氧元素能谱分析,最后通过超声滚压加工对比试验研究了空化效应对加工后材料表面粗糙度和显微硬度的影响。研究发现,超声滚压加工中的声压幅值远大于空化阈值,满足空化存在的必要条件;超声滚压中发生了明显的卡纸染色现象,引入切削液后工件超声滚压加工表面氧元素含量显著提高,表明超声滚压中发生了空化现象。超声滚压加工中的空化效应能进一步降低工件表面粗糙度和提高表面显微硬度,有利于提高工件表面强化质量。本研究为空化效应在超声滚压中的积极利用提供了依据。     

基于超声波飞行时间的温度测量系统实验研究

超声波测量技术具有速度快、成本低、测量范围广等优点,广泛应用于多种工业领域。为满足工业中对温度测量的需求,本文提出了超声波温度测量系统。本系统基于超声波的传播速度与环境温度的关系,以STC12单片机作为系统硬件电路控制核心,采用幅度和相位调制的矩形波作为发射波,实现在恒温箱空气介质中固定距离下的超声波飞行时间的测量,以此确定介质的平均温度。测量数据由单片机传输到上位机进行处理和显示,并与恒温箱热电偶测得的温度对照,验证实验结果。实验结果证明本系统可以准确测量温度,温度范围约在35℃—90℃。     

超声测距变结构控制系统的研究

本文在超声测距系统中采用了变结构控制理论，根据所测物体的反射界面和介质性质，自动调节超声波发射换能器的功率，建立了超声测距系统的数学模型，对系统方程进行了理论分析，研究了变结构控制系统的设计方法，并结合应用实例，对钻井法凿井用超声波测井仪中超声测距系统进行了计算机仿真，并在实验室进行了实验。