单泡声致发光中泡内气体含量参数实验研究

液体中的含气量是单泡声致发光相空间的重要参数，对声致发光气泡的运动及发光有重要影响本文给出了一种使用插入式荧光光谱含氧量计测量稳态单泡声致发光的液体中气体含量参数的方法，并对这父键性参数与气泡平衡半径R0和声压Pa的关系进行了具体的研究，再次验证了扩散平衡、化学分解假设理论。     

单泡声致发光中声压与气泡最大半径的关系

1引言: 当一定幅度的超声波作用于水中时,水中的微小气泡会在声压的驱动下膨胀和塌缩,并不断成长为肉眼可见的气泡,这种现象就是声空化.当超声波的幅度继续增大,水中气泡的膨胀、塌缩更加激烈,会产生短暂发光,这就是声致发光.早期的观察到的声致发光都是来自大量空化泡的集体效应,所以称为多泡声致发光.1992年,Gaitan等人将超声波作用于除气水,实现了单个气泡在水中的悬浮、膨胀、塌缩和发光,发明了单泡声致发光[1],使得人们可以对发光的单个气泡的参数进行具体的研究.     

单泡声致发光中气泡运动的声压相关性

1.引言 在超声驻波的作用下,在除气水中可以实现单个气泡的超声悬浮,同时气泡也将会以驱动频率做膨胀塌缩运动,塌缩的剧烈程度随着声压的增加而变剧烈,当声压大到一定值时,在气泡的塌缩过程中就会发出光脉冲,这就是单泡声致发光(SBSL).既然SBSL是由于气泡的运动所产生的,那么研究气泡具体是如何运动的就变得十分重要,这将有助于了解声致发光的发光机理和过程.当然,影响声致发光的因素有很多,如声压、含气量、环境温度和压力、以及一些液体参数等等,其中激励声压是最根本的一个相关量.本文我们研究激励声压对气泡运动的影响.     

单泡声致发光中稀有气体的特征光谱

1引言 声致发光是一种将声能转化为光能的复杂的物理化学过程.大量在空间和时间都随机、不稳定的声致发光是多泡声致发光.而空间上固定,时间上具有周期性的是单泡声致发光.一直以来,只在多泡声致发光中发现了明显的谱线,所以认为多泡声致发光和单泡声致发光出于不同的机制.但是D.J.Flannigan和K.S.Suslick[1]以85%的浓硫酸为单泡声致发光的工作液体,观测到了明显的Ar原子谱线.根据原子发光理论可以很好地解释Ar原子谱线.本文试图对不同温度下Ne,Kr,Xe原子气泡的单泡声致发光特征谱线进行了理论计算,期待实验的验证.     

单泡声致发光——气泡的动力学特性

单泡声致发光现象中，气泡动力学特性的研究是十分重要的。文章由简单的振子模型及能量守恒定律，导出了不可压缩、弱粘滞流体中纯径向振动气泡的Rayleigh—Plesset方程，利用龙格-库塔法计算了不同驱动声压下的R(t)曲线，并对崩溃相气泡的聚能效应做了讨论。     

氯化铽水溶液中单泡声致发光的线光谱

0引言Gaitan等人在1992年首次实现了单个气泡的声致发光,即单泡声致发光[1](Single bubble sonoluminescence,缩写为SBSL)。而之前的气泡群声致发光现象称为多泡声致发光[2](Multi-bubble sonoluminescence,缩写为MBSL)。光谱测量一直是研究声致发光的有效手段之一。1995年,Matula等人[3]根据MBSL和SBSL的光谱,分析认为两者的区别是SBSL只有连续谱,而MBSL除了有连续     

单泡声致发光现象 - 气泡运动的Mie散射测量

单泡声致发光现象时间和空间的高重复性,为实验研究气泡动力学特性提供了可能。文章利用Dave倒推算法,计算气泡Mie散射光强随散射角和气泡半径的变化,并选择了散射角80°为实验测量位置。利用R P方程理论计算的R(t)曲线与Mie散射实测结果相拟合,定量研究了气泡平衡半径、压缩比及崩溃阶段气泡的能量转换,结果表明,随激励声压的增大,气泡所吸收的声能可能绝大部分转换成激波及热能,使泡内温度上升。     

瞬态单一声空化气泡的动力学过程及空化发光

1.引言 在1990年,Gaitan[1]发现悬浮在驻波声场中的单一空化气泡能象时钟一样精确地在每个崩溃时刻发出裸眼能看见的光--称之为声致发光.单泡声致发光现象从此引起了众多研究者的浓厚兴趣,很多科学家对其进行了深入而广泛的研究,得到了比较定量的数据,相关的理 论分析也得到快速的进展.     

溶液的杂质含量对单泡声致发光的影响

1引言: 在适当除气的液体中,单一气泡可以悬浮在超声驻波场的波腹处,并随声场的频率作周期性的膨胀和收缩,在收缩时将声能量高度集中,会产生发光的现象,称为单泡声致发光(Single Bubble Sonoluminecence)[1].这个现象的发现距今才十几年,还有许多地方需要探索和改进.     

浅谈磷酸中声致发光测量实验装置

简单地介绍了声致发光现象以及研究这一现象的意义。在此基础上详细地介绍了液体中实现声致发光的实验装置及其工作原理,以及声致发光光强测量装置。较为详细地叙述了信号发生器、功率放大器、可调电感、谐振腔(压电换能器)、磁力搅拌器、数字电压表、光电倍增管及数字示波器等部件在实验中的功能和作用、具体操作方法和实验步骤。根据测量得到的实验数据总结了影响声致发光现象的主要因素,即实验环境温度、驱动声压信号频率及驱动声压大小等等。对实验过程中遇到的一些问题给出解决方案,并提出了改善实验仪器的建议。     

Single bubble sonoluminescence and stable cavitation

A single bubble trapped at an antinode of an acoustic standing wave field in water can emit 50ps-140ps light pulses, called "single bubble sonoluminescence" (SBSL). It arouses much interest in physical acoustics because of its highly non-linear characteristics, high concentration of energy, and stable cavitation behavior. In this paper, bubble stability, the dynamic behavior of bubbles, non-invasive measurement of driving acoustic pressure and Mie scattering method are introduced.     

Luminescence of sodium atoms in aqueous solution during sonolysis in moving-single-bubble regime

Emission from excited sodium atoms (Na 589 nm) under the conditions of single-bubble sonoluminescence (SBSL) in the moving-bubble regime has been observed in aqueous NaCl solutions at concentrations within 2.5–6 mol/L. Atomic line emission in the gas phase was caused by the penetration of metal salt species inside the bubble, followed by the transition of Na atom to an excited state. Saturation with argon and a low temperature (from −10 to −15°C) of solution are factors that favor the SBSL of metal in solution of a nonvolatile salt. The results confirm the validity of the model of microdrop injection that explains the appearance of metal inside a bubble, its excitation, and subsequent atomic line emission during SBSL as related to deformations of the moving bubble.     

The segmented bidirectional single-loop topology for material flow systems

This paper introduces the segmented bidirectional single-loop (SBSL) flow topology for carrier-based material handling systems. This configuration is based on a single-loop flow-path structure that is divided into non-overlapping segments, each containing a single carrier operating in a bidirectional mode. The design procedure comprises a 0 - 1 mixed-integer formulation to determine the single-loop including the pickup and delivery station location. The second stage is a segmentation procedure to determine the non-overlapping segments in the loop. Finally the performance of the SBSL is evaluated by means of simulation.     

The pressure of light on gas bubbles: Compensation of the buoyancy force

We have calculated the pressure of light on a gas bubble in a liquid medium. The conditions of optical immersion are analyzed, under which the bubble in the liquid occurs in the state of a stable equilibrium. Peculiarities and the possible applications of the optical immersion effect are considered.     

The design of single crystal materials for magnetic bubble domain applications

The criteria for the existence of stable magnetic bubble domains and their potential in data storage applications are outlined. The development of single crystal materials capable of supporting such domains is reviewed. Particular emphasis is given to both the static and dynamic properties of bubble domains and to how, by careful materials design and preparation, the optimum balance of these properties can be attained.     

Influence of wettability on bubble formation in liquid

This paper presents experimental results of the surface phenomena effect on bubble formation from a single orifice in water and at nozzle in liquid aluminium with gas blowing at small flow rates. The usage of coated orifice in water and nozzles of different materials in the melt realized wide range of contact angles. The meaningful stages, termed (1) nucleation period, (2) under critical growth, (3) critical growth and (4) necking, were identified during bubble formation in a regime referring to simultaneous forced flow and surface tension control. It was revealed that bubble formation is substantially dominated by hysteresis of contact angle. Evolution of interface equilibrium and force balance conditions distinctive for bubble formation is clarified. X-ray fluoroscope was used to carry out in-situ observation of bubble formation in the melt. It was shown that bubble volume increased with wettability worsening both for aqueous and metallic systems. A further insight into the mechanism of the bubble formation was obtained by comparison of the bubble behaviour at the tip of the injection devices in liquid aluminium and at the orifice in water.     

一种考虑时延的双气泡耦合振荡模型

基于单气泡Keller-Miksis振荡方程,在考虑时延的情况下,建立了一种双气泡耦合振荡计算模型。该模型将气泡振荡的周期分成若干份,初始扰动引起第一个气泡的半径在极短时间内变化而产生振荡并辐射声压,声压在传播一定时间后作用到第二个气泡,第二个气泡同样在短时间内做耦合振荡并反馈到第一个气泡,然后重复此过程。利用数值仿真在此模型的基础上分别研究了气泡振幅、半径、间距等参数对耦合振荡的影响。结果表明:初始扰动越大、两个气泡半径越接近,气泡耦合效应越明显;初始半径和平衡半径较大的气泡对耦合振荡有显著影响,振荡的频率向低频移动;气泡间距越大,耦合效应越弱;在某个特定距离处,气泡耦合效应的阻尼会异常减小或者增大。     

The theory of the growth of vapor bubbles in a metastable liquid

The growth of a single bubble and a system of vapor bubbles in the initial state in thermal and mechanical equilibrium with a liquid has been considered. Linear and nonlinear solutions have been derived, and the effects of the radial inertia, viscosity of the liquid, interphase heat and mass exchange, and the conditions of the tightness of bubbles on the development of the process have been studied on their basis.     

超声作用下刚性壁面附近的双气泡脉动

在实际应用时,空化泡可能位于刚性壁附近。对刚性壁附近的空化泡脉动进行研究有利于更好地利用声空化。文章研究了刚性壁附近双气泡的动力学规律。研究结果表明,当两气泡与刚性壁距离相同时,气泡与壁之间的距离越大,刚性壁对辐射声波的反射越小,气泡脉动时能够达到的最大半径与最小半径的比值(即压缩比)也越大。若改变单个气泡与刚性壁的距离,则当两个气泡距离接近时,位置固定的气泡压缩比会减小。增大单个气泡的平衡半径,会使得两气泡脉动时的压缩比变小。此外,文章还对两气泡间距固定情况下,气泡压缩比与两气泡中心连线和壁面所成夹角之间的关系进行了讨论。