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Orbital angular momentum conversion of acoustic vortex beams via planar lattice coupling

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Chinese Physics B 2024年第9期33卷 413-420页

作者： qingbang han Zhipeng Liu Cheng Yin Simeng Wu Yinlong Luo Zixin Yang Xiuyang Pang Yiqiu Wang Xuefen Kan Yuqiu Zhang Qiang Yu Jian Wu College of Information Science and Engineering Hohai UniversityChangzhou 213200China College of Advanced Interdisciplinary Studies Nanhu Laser LaboratoryNational University ofDefense TechnologyChangsha 410073China School of Transportation Engineering Jiangsu Shipping CollegeNantong 226010China i-Lab Suzhou Institute of Nano-Tech and Nano-BionicsChinese Academy of SciencesSuzhou215123China

Orbital angular momentum(OAM)conversion is critical in understanding interactions between a structural sound field and a planar ***,we explore the evolution of a monochromatic acoustic vortex beam(AVB)that is scattered by a phononic crystal(PnC)or a correlated random *** phenomenon is ascribed to the enhanced orbit–orbit angular momentum coupling induced by the band *** modifying the coupling condition,accurate and continuous micromanipulation of AVBs can be achieved,including the transverse/lateral gravity shift,the dynamics of the phase singularities,and the spatial distribution of acoustic pressure,*** research provides insight to the inhomogeneous coupling of AVBs with both propagating Bloch waves and localized Anderson modes,and may facilitate development of novel OAM-based acoustic devices for active sound field manipulation.

关键词： acoustic vortex beam phononic crystal Anderson localization Imbert–Fedorov effect

基于深度学习的兰姆波SCF-TFM超分辨率成像

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仪器仪表学报 2024年第6期45卷 101-110页

作者：孙刘家韩庆邦靳琪琳葛考河海大学信息科学与工程学院常州213200

腐蚀和裂纹是结构板常见的缺陷形式,兰姆波在非贯穿型损伤处发生模式转换是制约兰姆波成像质量的主要因素。此外,声波衍射遵循瑞利准则,超声成像存在分辨率极限。本文设计了一个全卷积神经网络对接收信号进行分割与重构,实现目标模态的... 详细信息

腐蚀和裂纹是结构板常见的缺陷形式,兰姆波在非贯穿型损伤处发生模式转换是制约兰姆波成像质量的主要因素。此外,声波衍射遵循瑞利准则,超声成像存在分辨率极限。本文设计了一个全卷积神经网络对接收信号进行分割与重构,实现目标模态的自动拾取,抹除杂波和模式转换的干扰。提出符号相干因子全聚焦成像法(SCF-TFM),在全矩阵聚焦成像过程中施加符号相干因子,抑制非目标区域散射波对成像结果的干扰,同时考虑散射信号的幅值及相位信息,可以一定程度上突破瑞利准则的限制,实现超分辨率成像。实验结果表明:对于单个盲孔缺陷,该方法成像结果的横向分辨率比全聚焦提高62.41%,信噪比提升58.23%;而对于多个非对称盲孔缺陷,当缺陷间距大于瑞利准则分辨率极限时,该方法的信噪比提高了92.89%;缺陷间距小于瑞利准则分辨率极限时,该方法可以实现超分辨率成像。

关键词：兰姆波非对称盲孔缺陷全卷积神经网络 SCF-TFM 超分辨率成像

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混凝土缺陷信号变分模态分解与超声成像方法

应用声学 2024年第4期43卷 829-835页

作者：张奇韩庆邦孙刘家靳琪琳王溢秋刘志鹏河海大学信息科学与工程学院常州213200

混凝土的强散射特性限制了其中缺陷声波成像的分辨率。该文采用一种依据变分模态分解与全聚焦成像相结合的方法,将接收信号分解成多个本征模态函数,计算各本征模态函数与激励信号的相关系数,对信号加权重构以实现对特征信号的提取,从而... 详细信息

混凝土的强散射特性限制了其中缺陷声波成像的分辨率。该文采用一种依据变分模态分解与全聚焦成像相结合的方法,将接收信号分解成多个本征模态函数,计算各本征模态函数与激励信号的相关系数,对信号加权重构以实现对特征信号的提取,从而提高成像算法对混凝土缺陷间散射波互干扰的鲁棒性。通过设置对比试验,研究了不同缺陷混凝土结构中该信号处理方式对于成像结果的影响。试验结果表明,该方法对于弱散射及散射干扰具有更好的鲁棒性,相比基于原始数据的成像方法能够更好地还原混凝土内部结构。

关键词：混凝土超声检测变分模态分解本征模态函数

Investigation of cavitation bubble collapse in hydrophobic concave using the pseudopotential multi-relaxation-time lattice Boltzmann method

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Chinese Physics B 2021年第4期30卷 333-341页

作者： Minglei Shan Yu Yang Xuemeng Zhao qingbang han Cheng Yao Jiangsu Key Laboratory of Power Transmission and Distribution Equipment Technology Hohai UniversityChangzhou 213022China College of Computer and Information Hohai UniversityNanjing 210000China

The interaction between cavitation bubble and solid surface is a fundamental topic which is deeply concerned for the utilization or avoidance of cavitation *** complexity of this topic is that the cavitation bubble collapse includes many extreme physical phenomena and variability of different solid surface *** the present work,the cavitation bubble collapse in hydrophobic concave is studied using the pseudopotential multi-relaxation-time lattice Boltzmann model(MRT-LB).The model is modified by involving the piecewise linear equation of state and improved forcing *** fluid-solid interaction in the model is employed to adjust the wettability of solid ***,the validity of the model is verified by comparison with experimental results and grid-independence ***,the cavitation bubble collapse in a hydrophobic concave is studied by investigating density field,pressure field,collapse time,and jet *** superimposed effect of the surface hydrophobicity and concave geometry is analyzed and explained in the framework of the pseudopotential *** study shows that the hydrophobic concave can enhance cavitation effect by decreasing cavitation threshold,accelerating collapse and increasing jet velocity.

关键词： cavitation bubble hydrophobic concave lattice Boltzmann model pseudopotential model

流体-孔隙介质周期性粗糙界面超声波反射与透射特性研究

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声学技术 2024年第2期43卷 218-223页

作者：张煜静韩庆邦苏娜娜吴洋靳琪琳孙刘家河海大学物联网工程学院江苏常州213022

为了研究超声波在流体-孔隙介质周期性粗糙界面的传播特性,文章基于周期性锯齿粗糙界面的衍射模型分析孔隙介质开孔与闭孔状态下孔隙度对反射与透射的影响。通过孔隙介质比奥特(Biot)理论与光栅方程理论,得到包含各阶反射系数、透射系... 详细信息

为了研究超声波在流体-孔隙介质周期性粗糙界面的传播特性,文章基于周期性锯齿粗糙界面的衍射模型分析孔隙介质开孔与闭孔状态下孔隙度对反射与透射的影响。通过孔隙介质比奥特(Biot)理论与光栅方程理论,得到包含各阶反射系数、透射系数的线性方程组,再利用傅里叶变换进行数值计算,得到孔隙度与流体-孔隙介质周期性粗糙界面反射系数、透射系数之间的关系。结果表明,由于界面的周期性,频率对反射与透射系数的影响没有呈现一定的规律。但孔隙度对反射与透射系数有显著影响,且由于孔隙介质状态的差异性,导致反射与透射系数在开孔与闭孔时变化趋势不同。

关键词：孔隙介质粗糙界面反射系数透射系数

Second-order harmonic field characteristics at solid-solid interface with P wave incidence

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Chinese Journal of Acoustics 2020年第4期39卷 541-551页

作者： WU Ning han qingbang HONG Xiaomin College of IOT Engineering Hohai UniversityChangzhou 213022

The second-order harmonic field characteristics at the solid-solid interface with P wave incidence were evaluated according to the second-order potential *** isotropic solid-solid interface was established to solve the boundary value problem of second-order nonhomogeneous potential equation based on the Lagrange’s method of variation parameters.A numerical computation was performed to analyze the incident angle and second-order harmonic *** results show that the longitudinal wave and transverse wave displacements of second-order harmonic field rapidly increase at a specific incidence ***,the special solutions of displacement abruptly change for incident angle θ***,the effect of boundary surface on second-order harmonic sound field is also discussed.

关键词： theory. harmonic wave

Propagation dynamics of off-axis noncanonical vortices in a collimated Gaussian beam

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Chinese Physics B 2019年第3期28卷 192-196页

作者： Cheng Yin Xuefen Kan Hailang Dai Minglei Shan qingbang han Zhuangqi Cao Jiangsu Key Laboratory of Power Transmission and Distribution Equipment Technology Hohai UniversityChangzhou 213022China The State Key Laboratory on Fiber Optic Local Area Communication Networks and Advanced Optical Communication Systems Shanghai JiaoTong UniversityShanghai 200240China

It is widely accepted that an off-axis noncanonical vortex moves across the free-space diffracting Gaussian beam without rotation. But our analysis shows that the vortex swirls a while before it approaches infinite. By neglecting the divergence of the host beam, we focus on this rotation characteristics of the vortices in linear homogeneous media. For the symmetrical host beam, it is found that the vortex moves along an elliptical trajectory, while the topological charge and the angular momentum of the vortex core relative to the beam axis are conserved. For the asymmetrical host beam, the vortex trajectory is rather complicated, since the noncanonical parameter varies as the light propagates, resulting in topological charge inversion. But we find that the vortices are always confined in a rectangular area, and the rotation direction is determined by the topological charge.

关键词： noncanonical optical vortex topological charge inversion

Electric characteristic and cavitation bubble dynamics using underwater pulsed discharge

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Plasma Science and Technology 2019年第7期21卷 16-22页

作者： Minglei Shan Bingyan CHEN Cheng YAO qingbang han Changping ZHU Yu YANG Jiangsu Key Laboratory of Power Transmission and Distribution Equipment Technology Changzhou 213022People’s Republic of China College of Internet of Things Engineering Hohai UniversityChangzhou 213022People’s Republic of China Key Laboratory of Unmanned Aerial Vehicle Development&Data Application of Anhui Higher Education Institutes Wanjiang University of TechnologyMa’anshan 243031People’s Republic of China

Underwater pulsed discharge is widely applied in medicine, machining, and material *** induced cavitation bubble and subsequent cavitation collapse are considered the major motivations behind these applications. This paper presents an underwater pulsed discharge *** experimental setup is established to induce and investigate the cavitation bubble assisted with a high-speed camera. Three aspects, including the characteristic of the discharge with different applied voltages and conductivities, the evolution of the cavitation bubble profile, and the energy efficiency of cavitation bubble inducing, are investigated, respectively. Especially, the mechanism of pre-discharge time delay in the low field intensity case is explained using the Joule heat *** results show the validity of the underwater pulsed discharger and experimental setup. The present underwater pulsed discharger is proved to be a simple, portable, and easy-to-implement device for the investigation of cavitation bubble dynamics.

关键词： underwater pulsed discharge cavitation bubble electric discharge characteristic high-speed camera

Propagation characteristics of low-frequency axisymmetric waves in fluid-filled pipes embedded in the viscoelastic medium

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Chinese Journal of Acoustics 2022年第3期41卷 221-237页

作者： QIAN Jiawen han qingbang SU Nana BAI Le QIAN Xintong College of IOT Engineering of Hohai University Changzhou 213022

The propagation characteristics of the low-frequency axisymmetric waves in buried fluid-filled pipes are investigated theoretically,based on the Kennard thin-walled shell equations,the Helmholtz equation,and the Kelvin-Voigt linear viscoelastic *** expressions of the phase velocity are derived for both the fluid-dominated wave and the shell-compressed wave under lubricated contact,via considering the surrounding soil as a viscoelastic *** dispersion and attenuation curves of the two wave types are obtained and verified *** ratio of the radial pipe wall displacements is analyzed,with particular emphasis on the effects of the thickness-to-radius ratio and the quality factor on the dispersion and attenuation characteristics of the fluid-dominated *** results show that the viscoelastic property has slight effects on the phase velocities of the two wave types,but it influences the attenuation *** fluid-dominated wave influences the radial pipe wall displacement significantly and is the primary carrier of leakage noise energy;its phase velocity increases as a function of the thickness-to-radius ratio while the attenuation *** also shows that the dispersion and attenuation of the fluid-dominated wave decrease as a function of the quality *** work will provide insights and guidance for the leakage detection of buried fluid-filled pipes.

关键词： wave viscoelastic filled