Intermediate regime of light diffraction by surface ultrasonic waves in planar gyrotropic optical waveguides

The intermediate regime of optoacoustic interaction, similar to the Bragg one, with Rayleigh surface ultrasonic waves in gyrotropic planar waveguides is studied. A system of equations of bound waves is presented that describes planar optoacoustic interaction in the intermediate, Raman-Natoh, and Bragg regimes of light diffraction by surface ultrasonic waves. It is shown that the optical activity of a wavequide film favors the incident light energy pumping to diffracted light for a TE-polarization wave and decelerates this process for an incident TM-polarization wave. Mozyr' State Pedagogical Institute, 28, Studencheskaya St., Mozyr', 247760, Belarus. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 3, pp. 412–416, May–June, 1997.     

Sonocrystallization of polycarbonate melts

In this paper, we showed the simplified continuous process to crystallize the polycarbonate (PC) melts using sonocrystallization which is based on ultrasonic cavitation and ‘hot spot’ theory. High power ultrasonic wave was introduced to crystallize the PC prepolymers which is generally used for solid‐state polymerization (SSP) to obtain the ultra‐high molecular weight PCs. The structure and properties of PC treated with ultrasonic wave such as torque changes and crystallinities were studied. The experimental results showed that ultrasonic wave could improve the crystallinities of PCs and sonication time was proportional to their crystallinity. This is attributed to the decrease of the specific volume and the resulting shrinkage is compensated by a flux of a polymer melt toward the crystallization front. Torque data were collected directly from the Haake internal mixer and crystallinities were evaluated from differential scanning calorimeter (DSC). This process is an environmentally benign process so that no additional solvents or treatments are needed and will be very useful in the conventional solid‐state process which is used industrially. Copyright © 2007 John Wiley & Sons, Ltd.     

探测超声微振动的激光外差干涉仪

激光超声是一项新兴的技术，可应用于非接触检测。本文作者研制的探测超声微振动的激光外差干涉仪，该装置具有结构简单，不必采用复杂的反馈回路，只要采用简单的滤波就可以消除外界环境引起的干扰，更重要的是它的测量结果与干涉仪的初相无关，为实际应用提供了很大方便。     

Effect of frequency on sonochemical reactions. I: Oxidation of iodide

The effect of continuous sonication on the kinetics of iodine formation in aqueous iodide solutions was studied in the presence of air and argon at two frequencies, 20 and 900 kHz. Most workers in this area assume that frequency has a negligible effect on sonochemical reactions. The present results indicate, however, that there is a significant effect in the above solutions. The rate of sonochemical oxidation of iodide in aqueous solution is 3.1 times greater in presence of air than argon at 900 kHz, in contrast to the situation at 20 kHz, where the ratio is 0.9 A 900 kHz apparatus was specially designed to make it possible to measure the absolute acoustic power delivered into the solution. The rate of oxidation per unit power in this new 900 kHz apparatus can be more than 30 times greater than that at 20 kHz for the oxidation of iodide in the presence of air.     

SJTU-1型医用超声诊断设备声输出测量系统的研制

本系统地研究了医用超声诊断设各声输出公布要求的国家标准GB16846—1997(idt.IEC61157—1992)中规定的主要指标的定义和测量方法，给出了相关的计算公式。介绍了为实施国标而研制的专用测量设备SJTU-1型医用超声设备声输出测量系统的工作原理、系统构成和技术性能。     

石油醚在流体静高压下的超声声速、衰减、密度和绝热压缩系数

 专门设计了用脉冲-回波-重合法在不同静水压下测量液体声速的装置，并对石油醚在0.1~650 MPa流体静压力范围内测量了其超声声速和衰减系数。还通过测量体积压缩量和质量得到石油醚密度ρ随流体静压力的变化。最后，给出了石油醚的绝热压缩系数β与流体静压力的关系。     

简易超声波换能器频率测试仪的研究

对超声波换能器频率测试系统进行了探讨，并在此基础上提出了改装设想，分析了所研究的简易超声波换能器频率测试仪的电路原理及实验结果。     

Ultrasonic velocity hydration numbers of polyamines

Ultrasonic velocity hydration numbers of diamines, triamines and tetraamines and hydrochlorides of these amines were determined by measuring the maximum velocity of ultrasound in aqueous-ethanolic solutions. The results are interpreted on the basis of the hydrogen-bonded framework model of the water structure.     

B型套筒角焊缝缺陷相控阵超声检测定量方法

B型套筒修复作为油气管道修复的主要方式之一,在其修复的焊接过程中,该结构的环形角焊缝内部常常出现以气孔、夹渣为代表的孔型缺陷。这类缺陷由于角焊缝特殊的结构,在利用相控阵超声无损检测技术对其检测时,难以对其进行定量分析。通过数值模拟和实验,发现通过相控阵超声扇扫得到缺陷回波信号峰值与孔型缺陷直径呈正相关,为孔型缺陷的定量分析提供了一种可靠的手段。     

固-固界面退化特性的超声反射评价方法

提出了一种基于有限宽超声束反射的固-固界面退化特性评价方法,从理论和数值仿真角度进行了分析和计算。将两固体界面间的薄层简化为界面弹簧模型,以界面法向和切向劲度系数表征界面的退化程度。通过数值计算求得有限宽超声纵波束在不同入射角和界面不同退化程度下的反射横波、反射纵波的镜面反射系数。进一步地,通过建立二维有限元模型,仿真研究了有限宽超声纵波束在给定入射角及界面不同退化程度下镜面反射系数的变化规律。结果表明,反射纵波和反射横波的镜面反射系数随有限宽超声纵波束的入射角及界面劲度系数的改变而变化,且存在镜面反射系数随界面劲度系数单调且敏感变化的入射角,据此可准确评价界面的退化程度。