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2004年全国物理声学学术交流会(第十届)于2004年10月22日至25日在江苏省镇江市召开。本届会议是由中国声学学会物理声学分会和江苏省声学学会物理声学专业委员会联合举办,由南京大学声学所和江苏大学承办。 本届会议的主题是"新世纪4年来声学各分支领域中物理声学研究的新进展"。会议收到论文65篇,其中大会综述报告2篇,非线性声学18篇,量子声学、声传播及其物理效应24篇,光声、热声和检测声  相似文献   
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报导了水基和酯基磁性流体的非线性声参量B/A值随浓度和温度的变化关系。实验研究表明,磁性流体的B/A值随磁性颗粒浓度的增大而线性增大;磁性流体的B/A值随温度的升高而线性增大。还对超声波在磁性流体中传播的声速进行了精确测量。  相似文献   
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欧阳灵  刘晓宙  刘杰惠  龚秀芬 《物理学报》2014,63(10):104304-104304
纳米力学方法适用于具有离散特性的材料.利用纳米力学方法,得出声波在多层皮肤组织中的波动方程.分别改变黑素瘤皮肤的泊松比、黑素瘤侵袭厚度(Breslow深度)、节间距离,计算多层皮肤结构模型对垂直入射纵声波的反射系数.同时计算了声速和声衰减系数随组织参数的变化.计算结果表明,可综合利用一定频率段内反射系数最小点数、声速和衰减系数的变化来表征正常皮肤和病变皮肤.  相似文献   
4.
Based on the angular spectrum decomposition and partial-wave series expansion methods, we investigate the radiation force functions of two Airy-Gaussian(AiG) beams on a cylindrical particle and the motion trajectory of the particle. The simulations show that the particle can be pulled or propelled into either the positive or negative transverse direction by turning the phase difference between the two AiG beams appropriately; and the larger the beam widths of the two AiG beams are, the bigger the radiation force can be obtained to control the particle. In addition, the direction of the accelerated particle can be controlled while the dimensionless frequency bandwidth changes. The results indicate that the phase plays an important role in controlling the direction of the particle, which may provide a theoretical basis for the design of acoustical tweezers and the development of drug delivery.  相似文献   
5.
In order to improve the operability and accuracy of high-intensity focused ultrasound(HIFU), an annular focused transducer, whereby a B-ultrasound probe is placed in its center, is used to realize the real time monitoring and control of the treatment. In this paper, the spheroidal beam equation(SBE) was used to calculate the sound field by an annular focused transducer with a wide aperture angle to first derive the heat deposition and the Pennes equation was used to calculate the temperature field in multi-layer tissue. We studied the effect of different parameters on the temperature of the tissues. The result shows that the focal length has a significant influence on both maximum liver temperature rise and skin temperature rise, and both increase with the increase in the focal length. When the frequency increases, the temperature rise first undergoes a rapid increase before gradually reaching a maximum, and then finally decreasing. The temperature rise increases while the inner radius decreases or the sound pressure increases. By choosing suitable parameters, the proper temperature rise both on the target tissue and skin via an annular focused transducer with a wide aperture angle can be obtained.  相似文献   
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Based on an equivalent medium approach,this paper presents a model describing the nonlinear propagation of acoustic waves in a viscoelastic medium containing cylindrical micropores.The influences of pores’ nonlinear oscillations on sound attenuation,sound dispersion and an equivalent acoustic nonlinearity parameter are discussed.The calculated results show that the attenuation increases with an increasing volume fraction of micropores.The peak of sound velocity and attenuation occurs at the resonant frequency of the micropores while the peak of the equivalent acoustic nonlinearity parameter occurs at the half of the resonant frequency of the micropores.Furthermore,multiple scattering has been taken into account,which leads to a modification to the effective wave number in the equivalent medium approach.We find that these linear and nonlinear acoustic parameters need to be corrected when the volume fraction of micropores is larger than 0.1%.  相似文献   
7.
平面行波场中多个粒子受到的声辐射力*   总被引:1,自引:1,他引:0  
从粒子在行波场中的声散射出发,研究当声场中存在稀疏分布的多个粒子时粒子受到的声辐射力,并且给出了适用于声场中任意位置的粒子声辐射力计算公式。由于声辐射力为非线性力,当声场中存在多个粒子时,直接计算粒子受到的声辐射力非常复杂。结果表明,当声场中存在多个稀疏分布的粒子时,这一多粒子系统可以视为多个单独的双粒子系统的叠加,只需要分别计算各个双粒子系统的声辐射力就可以通过叠加得到声场中任意粒子的声辐射力。这一结果有助于利用声辐射力对微小粒子进行精细操控。  相似文献   
8.
振动声成像是超声成像的一种重要形式,它可以得到包含共焦区组织的弹性信息和声衰减信息的信号,将接收到的信号用于成像即可获得反映组织特性的图像。该文对大张角共焦换能器作用下振动声成像中声辐射力和切变位移进行了理论计算和数值模拟,并通过改变张角变化及频率大小研究其对声辐射力和切变位移的影响。这项工作为大张角共焦换能器在振动声成像中的应用提供了理论支持。  相似文献   
9.
We develop a model for calculating the radiation force on spherically symmetric multilayered particles based on the acoustic scattering approach. An expression is derived for the radiation force on a multilayered sphere centered on the axis of a Gaussian standing wave propagating in an ideal fluid. The effects of the sound absorption of the materials and sound wave on acoustic radiation force of a multilayered sphere immersed in water are analyzed, with particular emphasis on the shell thickness of every layer, and the width of the Gaussian beam. The results reveal that the existence of particle trapping behavior depends on the choice of the non-dimensional frequency ka, as well as the shell thickness of each layer. This study provides a theoretical basis for the development of acoustical tweezers in a Gaussian standing wave, which may benefit the improvement and development of acoustic control technology, such as trapping, sorting, and assembling a cell, and drug delivery applications.  相似文献   
10.
随着科学技术的发展,声辐射力在生物医学领域得到了更为广泛的应用,尤其是在弹性成像领域。为了使弹性成像技术更加精准,对声辐射力的预测至关重要。该文基于腹壁组织图像,利用k-Wave对超声波在腹壁组织区域传播时的声场进行数值模拟,获得了其声场分布,进而求得了组织中声辐射力分布情况,同时对面阵换能器的阵元宽度、间距、阵元个数以及工作频率等参量对声辐射力的影响进行了计算与分析。结果表明,腹壁组织的声场分布受其非均匀性的影响,声辐射力的分布情况依赖于换能器参量的选择。该研究为声辐射力在弹性成像技术中的应用奠定了基础,为其技术的改进提供了重要依据。  相似文献   
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