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sound

廉政瞭望 2010年第9期 3-3页

接待就是硬道理,接待就是生产力。——基层干部对泛滥的公务接待已不胜其烦,但广西某县级市还是提出了这样的口号抢劫、放高利贷、当小姐——成都某社区小朋友财商培训课上,老师问如何赚钱

关键词：为人民服务 sound 财商央企刘翔标准答案公务接待人像小姐县级市生产力生产方式放高利贷

sound Source Localisation for a High-Speed Train and Its Transfer Path to Interior Noise

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Chinese Journal of Mechanical Engineering 2019年第4期32卷 168-183页

作者： Jie Zhang Xinbiao Xiao Xiaozhen Sheng Zhihui Li State Key Laboratory of Traction Power Southwest Jiaotong University

Noise is one of the key issues in the operation of high-speed railways, with sound source localisation and its transfer path as the two major aspects. This study investigates both the exterior and interior sound source distribution of a high-speed train and presents a method for performing the contribution analysis of airborne sound with regard to the interior noise. First, both exterior and interior sound source locations of the high-speed train are identified through in-situ measurements. Second, the sound source contribution for di erent regions of the train and the relationships between the exterior and interior noises are analysed. Third, a method for conducting the contribution analysis of airborne sound with regard to the interior noise of the high-speed train is described. Lastly, a case study on the sidewall area is carried out, and the contribution of airborne sound to the interior noise of this area is obtained. The results show that, when the high-speed train runs at 310 km/h, dominant exterior sound sources are located in the bogie and pantograph regions, while main interior sound sources are located at the sidewall and roof. The interior noise, the bogie area noise and the sound source at the middle of the coach exhibit very similar rates of increase with increasing train speed. For the selected sidewall area, structure-borne sound dominates in most of the 1/3 octave bands.

关键词： High-speed train Interior noise sound transfer path Noise source identification Exterior noise Airborne sound

sound Velocity in Soap Foams

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Chinese Physics Letters 2012年第10期29卷 81-84页

作者： WU Gong-Tao LÜYong-Jun LIU Peng-Fei LI Yi-Ning SHI Qing-Fan School of Physics Beijing Institute of TechnologyBeijing 100081

The velocity of sound in soap foams at high gas volume fractions is experimentally studied by using the time difference *** is found that the sound velocities increase with increasing bubble diameter,and asymptotically approach to the value in air when the diameter is larger than 12.5 *** propose a simple theoretical model for the sound propagation in a disordered *** this model,the attenuation of a sound wave due to the scattering of the bubble wall is equivalently described as the effect of an additional *** simplicity reasonably reproduces the sound velocity in foams and the predicted results are in good agreement with the *** measurements indicate that the increase of frequency markedly slows down the sound velocity,whereas the latter does not display a strong dependence on the solution concentration.

关键词： Velocity sound Soap

sound intensity radiated by Gaohu

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Science China(Technological Sciences) 2010年第7期53卷 1792-1797页

作者： ZHAO YueZhe1, WU ShuoXian1, QIU JianZhen1, HUANG Hong2 & WU LiLing2 1 State Key Laboratory of Subtropical Building Science, South China University of Technology, Guangzhou 510640, China 2 Department of Musicology, Xinghai Conservatoire of Music, Guangzhou 510500, China 1. State Key Laboratory of Subtropical Building Science South China University of Technology Guangzhou 510640 China2. Department of Musicology Xinghai Conservatoire of Music Guangzhou 510500 China

Gaohu is one of the main bowed stringed instruments used in Guangdong music and Chinese native Orchestra. However its sound intensity has never been carefully measured. In this paper the sound power measurements of Gaohu were performed in a reverberation chamber according to the Chinese national standard. Two qualified musicians performed on their own instruments. The mean sound power levels and the dynamic ranges of Gaohu were investigated by four channel acoustic measuring equipments when single notes, music scale and melodies were performed under pp, mp, f and ff dynamics. Great differences were found when Gaohu performed single notes, while the sound power levels were quite close when music scale were performed under f dynamic to those when melodies were performed under normal dynamic mark, the sound power levels of Gaohu when music scale was performed under f dynamics were suggested as the typical and representative value of the sound intensities of Gaohu instrument.

关键词： Gaohu Guangdong music sound intensities sound power level

sound speed in bubble film of ship wakes

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Science China(Physics,Mechanics & Astronomy) 2008年第1期51卷 64-71页

作者： ZHANG JianSheng LIN ShuYu LIU Peng MIAO RunCai YANG WanMin Physics Department Shaanxi Normal UniversityXi’an 710062China Math-physical Department Xi’an Technological UniversityXi’an 710032China

As is distinct from general gas-liquid two-phase flow,a large number of bubbles with different diameters belong to ship *** of Laplace equation,used to calculate wake sound speed(WSS),is confirmed based on differential postula- *** for calculating the adiabatic sound speed of gases in references is showed,and a concept of WSS is proposed clearly.A minimum WSS of 24.5 m/s is got when bubble ratio reads 0.5 according to the calculation when bubble dimen- sion is less than that of *** a weak dependence of WSS on pressures is *** from calculation corresponds with the experimental data of ref- erences well in high frequency domain,when the actual scale of bubbles is greater than the resonant scale.

关键词： ship wake bubble film Laplace equation resonant frequency sound speed

Relation between the Three-dimensional Flow Structure and Aerodynamic sound Generated from Inclined Circular Cylinder

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Journal of Thermal Science 2004年第2期13卷 127-132页

作者： Mitsuru SHINGAI Yasutake HARAMOTO Kazuyoshi MATSUZAKI Mizue MUNEKATA Hideki OHBA Dept. of Mechanical Engineering and Materials Science Kumamoto University Kurokami 2-39-1 Kumamoto 860-8555 Japan Mitsui Miike Machinery Co. LTD Asahi-machi 2-28 Ohmuta Fukuoka 836-8588 Japan

The major causes of the sound pressure level (SPL) variation due to the changes of the inclined angle of a circular cylinder and the aspect ratio (ratio of distance between endplates to cylinder diameter) were investigated. The velocity fluctuation of the wake and the surface pressure fluctuation of the cylinder were measured in a low noise wind tunnel to find the correlation length, coherent output power and Strouhal number. The results show that the changes of these values qualitatively correspond with the change of SPL. Flow visualization tests are performed to clarify the variation of wake in relation with inclined angle and aspect ratio. It is found that the spanwise structure of Karman’s vortex street is broken down by the upward flows generated around the bottom endplate, and the degree of the interference between the upward flow and Karman’s vortex street is smaller when the aspect ratio is larger.

关键词： aerodynamic sound correlation length coherent output power Strouhal number flow visualization.

An mm-sized biomimetic directional microphone array for sound source localization in three dimensions

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Microsystems & Nanoengineering 2022年第3期8卷 77-89页

作者： Ashiqur ahaman Byungki Kim School of Mechatronics Engineering Korea University of Technology and EducationCheonan 31253Republic of Korea Future Convergence Engineering Korea University of Technology and EducationCheonan 31253Republic of Korea

Fly Ormia ochracea ears have been well-studied and mimicked to achieve subwavelength directional sensing,but their efficacy in sound source localization in three dimensions,utilizing sound from the X-,Y-,and Z-axes,has been less *** paper focuses on a mm-sized array of three Ormia ochracea ear-inspired piezoelectric MEMS directional microphones,where their in-plane directionality is considered a cue to demonstrate sound source localization in three *** the array,biomimetic MEMS directional microphones are positioned in a 120°angular rotation;as a result,six diaphragms out of three directional microphones keep a normal-axis relative to the sound source at six diferent angles in the azimuth plane starting from 0°to 360°in intervals of±30°.In addition,the cosine-dependent horizontal component of the applied sound gives cues for Z-axis directional *** whole array is frst analytically simulated and then experimentally measured in an anechoic *** results are found to be compliant,and the angular resolution of sound source localization in three dimensions is found to be±2°at the normal *** resolution at the azimuth plane is found to be±1.28,and the same array shows a±4.28°resolution when sound is varied from the elevation *** at the scope within this area combined with the presented results,this work provides a clear understanding of sound source localization in three dimensions.

关键词： directional dimensions sound

Influence of warm eddies on sound propagation in the Gulf of Mexico

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Chinese Physics B 2019年第5期28卷 134-144页

作者： Yao Xiao Zhenglin Li Jun Li Jiaqi Liu State Key Laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences University of Chinese Academy of Sciences China State Shipbuilding Corporation (CSSC) Systems Engineering Research Institute College of Underwater Acoustic Engineering Harbin Engineering University Woodruff School Mechanical Engineering Georgia Institute of Technology

An automatic detection method is employed to identify and track eddies in the Gulf of Mexico. The physical parameters of the eddies, such as lifespan, radius, and distribution position are first examined and used to determine the spatio–temporal evolution of a strong warm eddy separated from the Mexico current. Then, the influence of this strong warm eddy on sound propagation during its lifespan are comprehensively analyzed with the parabolic equation and explained by using the normal mode and ray theories. Additionally, the influence of mesoscale eddies on the redistribution of total depth-integrated energy among the normal modes in the deep water is also discussed. The variation of arrival angle is investigated to explain the spreading acoustic energy caused by eddies. Overall, the results show that warm eddies can change the propagation paths and cause the convergence zone to broaden and approach the sound source. Moreover,the warm eddy can disperse sound energy and cause the total depth-integrated energy to incline to a lower normal *** the whole of these three periods(eddy generating, eddy maturing, and eddy terminating), the fluctuation in the transmission loss is up to 30 dB(depending on the relative location of eddy center to the source).

关键词： mesoscale eddies sound propagation mode coupling acoustic energy disturbance

Relationship between sound signal and weld pool status in plasma arc welding

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中国有色金属学会会刊：英文版 2001年第1期11卷 54-57页

作者：王耀文陈强孙振国孙久文 Tsing Hua Univ Dept Mech Engn Beijing 100084 Peoples R China

The sound features of the weld pool status in plasma arc welding were systematically investigated after the sound signal was collected with a microphone. The results show that it is difficult to extract information about the weld pool status directly in time domain although the sound signal varies with the weld pool behaviors to some extent. The frequency spectra of the sound signal contain plenty of information about the weld pool behaviors. It is shown from the analysis of the sound generation mechanism that the sound signal of plasma arc welding is mainly caused by the weld pool oscillation, the power source fluctuation and so on. R S algorithm is designed to determine the weld pool status, and it is able to offer the feedback information for the closed loop control of the penetration quality of plasma arc welding. [

关键词： plasma arc welding weld pool status sound feature application