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31.
Dynamics of a single cavitation bubble in sodium dodecyl sulfate(SDS) aqueous solutions is investigated experimentally and theoretically. The bubble pulsation is measured by a phase-locked integrated imaging technique,and the ambient radius is obtained by fitting the numerical calculation based on the Rayleigh–Plesset bubble dynamics model to the experimental data. The results show that, under the same driving condition, the ambient radius of the cavitation bubble decreases correspondingly with the increase of SDS concentration within the critical micelle concentration, while the compression ratio of the radius increases, which indicates that the addition of SDS decreases the internal molecular number of the cavitation bubble and increases the power capability of the cavitation bubble. In addition, bubble oscillation increases the concentration of the surfactant molecules on the bubble wall, so that the effect of SDS on a single cavitation bubble is reduced when the SDS concentration is greater than 0.8 m M. 相似文献
32.
在溶有稀有气体的稀土盐氯化铽水溶液中进行了单泡声致发光光谱的研究. 在固定驱动超声频率、不同驱动声压下, 观察到了一系列OH自由基从第一激发态A2∑+到基态X2Π 各振动能级跃迁所产生的谱线, 包括波长307 nm处的(0, 0)跃迁谱线, 335 nm处的(0, 1)跃迁谱线以及276 nm处的(1, 0) 跃迁谱线等. 实验结果表明较高的驱动声压有利于 276 nm处谱线的产生, 而较低的驱动声压则有利于 307 与 335 nm 处谱线的产生. 通过定义线状光谱与连续谱的光强比, 定量地表征了线状光谱在总光谱中的相对强度, 并给出了驱动声压对各跃迁谱线光强比的影响.
关键词:
单泡声致发光
驱动声压
线状光谱
光强比 相似文献
33.
<正>This paper studies the hydrodynamic solitons propagating along a long trough with a defective bed.The slight deviation from the plane in the bed serves as the depth defects.Based on the perturbation method,it finds that the free surface wave is governed by a Korteweg-de Vries(KdV) equation with a defect term(KdVD).The numerical calculations show that,for a single-convexity localized defect,the propagating soliton is decelerated as it comes into the defect region,and it is accelerated back to its initial velocity as it leaves,which has a dipole effect.As a result, its displacement is lagged in contrast to the uninfluenced one.And an up-step defect makes the propagating soliton decelerate simply.The opposite influence will occur for a single-concavity localized defect and a down-step one.The defect-induced influence on propagating hydrodynamic solitons depends on the polarity of defects,which agrees with that on non-propagating ones.However,the involved dipole effect of the single localized defect is not displayed in non-propagating cases. 相似文献
34.
The phenomenon of energy unidirectional transmission is numerically investigated by using a system of two coupled discrete nonlinear electrical transmission lines, each line of the network contains a finite number of cells and has different pass band structures, respectively. Using numerical simulations, we examine the frequency multiplication of the driving frequency and the lattice filtering effect in the line. These lead to the generation of energy unidirectional transmission. In the present work, energy is carried by the second harmonic wave in the pass band. In addition, we also study the dependence of the energy efficiency on the driving amplitude and other parameters of the model, such as the system size and the nonlinear coefficient, by calculation. Furthermore, after detailed numerical simulation, an experimental demonstration is realized. The experimental results agree with those in simulation qualitatively. 相似文献
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双路Mie散射测量空化泡的非同步振荡 总被引:1,自引:0,他引:1
通过双路Mie散射方法,我们从不同方向测量了超声驱动声空化泡的表面脉动情况.结果显示,在低声压驱动下,两个方向测到的Mie散射信号是不同步,存在相位差.这表明不同方向的气泡表面的脉动是不同步的.作为一个推论,此时气泡的形状是非球形的.幸运的是,高声压驱动的声致发光气泡没有观察到相位差,没有证据显示它的运动是非球形的. 相似文献
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采用分子动力学方法模拟研究了孤立波在重轻颗粒相间排列的一维复合颗粒链中的传播特性.结果发现,在轻重颗粒的质量比较大或较小时,散射作用较弱,颗粒的速度和孤立波的速度衰减较慢.在轻重颗粒的质量比为中等时,散射作用较强,颗粒的速度和孤立波的速度衰减较快.孤立波在通过重-轻颗粒界面时,存在有增速效应,可以提高孤立波的传播速度.并且,轻重颗粒的质量比越小增速效应越强.在散射作用和增速效应的共同作用下,改变轻重颗粒的质量比可以调控孤立波在重-轻颗粒链中的传播时间. 相似文献
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Experiments of the temperature effect on single bubble sonoluminescence (SBSL) are performed with a mixture of water and anti-freeze.Since experiments of constant pressure (keeping sound pressure constant) are not feasible for a wide temperature range,experiments of constant luminance (keeping light intensity stable),which reflect pure sensitivity of SBSL to temperature,are investigated.The results show that lower temperature needs less pressure to obtain the same light intensity,which means that lower temperature is better for SBSL.Numerical calculations show a qualitative agreement with experiments. 相似文献