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Research on attenuation characteristic of sound wave in coal or rock body

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Journal of Coal Science & Engineering(China) 2007年第2期13卷 154-158页

作者：聂百胜何学秋李祥春高虹 State Key Lab．of Coal Resources and Safe Mining China University of Mining ＆ Technology（Beijing）Beijing 100083China School of Resource and Safety Engineering China University of Mining and Technology（Beijing）Beijing 100083China

In order to using power sound wave increase permeability of coal, rules of attenuation of sound wave in coal should be studied. In this paper, characteristic and mechanism of attenuation of sound wave in coal was researched according to acoustic theory and attenuation coefficients was estimated by acoustic parameter of coal. The research results show that the main attenuation mechanism of sound wave in coal is absorption attenuation and scattering attenuation. The absorption attenuation includes viscous absorption, thermal conduction absorption and relaxation absorption. Attenuation coefficient of sound wave in gaseous coal is 38.5 Np/m. Researches on attenuation characteristic of sound wave will provide the theoretical basis for power sound wave improving permeability of coal and accelerating desorption of coal bed gas.

关键词： sound wave coal or rock body attenuation characteristic

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sound wave声望语音卡

信息方略 1994年第3期 25-25页

sound wave(Ver.B)声望语音卡是由思安公司研制(海华公司联合开发)的国内第一家与MS Windows3.1及sound Blaster全兼容的语音卡,并带有汉字发音功能。主要功能: 16位、8位可选数字化录音与放音,兼容立体声44.1kHz格式

关键词：语音卡 sound wave 立体声

New Method in Calculating the Trajectory of sound waves at Stratified Ocean

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Open Journal of Acoustics 2016年第2期6卷 13-21页

作者： V. P. Ivanov G. K. Ivanova Institute of Applied Physics Russian Academy of Sciences Nizhny Novgorod Russia

There is a new method of calculating the trajectory of sound waves (rays) in layered stratified speed of sound in ocean without dispersion. A sound wave in the fluid is considered as a vector. The amplitudes occurring at the boundary layers of the reflected and refracted waves are calculated according to the law of addition of vectors and using the law of conservation of energy, as well as the laws that determine the angles of reflection and refraction. It is shown that in calculating the trajectories, the reflected wave must be taken into account. The reflecting wave’s value may be about 1 at certain angles of the initial wave output from the sours. Reflecting wave forms the so-called water rays, which do not touch the bottom and the surface of the ocean. The conditions of occurrence of the water rays are following. The sum of the angles of the incident and refracted waves (rays) should be a right angle, and the tangent of the angle of inclination of the incident wave is equal to the refractive index. Under these conditions, the refracted wave amplitude vanishes. All sound energy is converted into the reflected beam, and total internal reflection occurs. In this paper, the calculation of the amplitudes and beam trajectories is conducted for the canonical type of waveguide, in which the speed of sound is asymmetric parabola. The sound source is placed at the depth of the center of the parabola. Total internal reflection occurs in a narrow range of angles of exit beams from the source 43° - 45°. Within this range of angles, the water rays form and not touch the bottom and surface of ocean. Outside this range, the bulk of the beam spreads, touching the bottom and the surface of the ocean. When exit corners, equal and greater than 77°, at some distance the beam becomes horizontal and extends along the layer, without leaving it. Calculation of the wave amplitudes excludes absorption factor. Note that the formula for amplitudes of the sound waves applies to light waves.

关键词： sound wave Rays Water Ray Trajectory Liquid Space

A method for visualizing sound propagation in solids and liquids

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Acta Seismologica Sinica(English Edition) 2006年第6期19卷 670-676页

作者：沈建国张宏敏 Tianjin University Tianjin 300072 China

A new method for visualizing sound propagation in solids and liquids is described in this paper. The method can show the sound propagation process dynamically in two dimensions. Compared with Schlieren method and dynamic photo-elastic method, this method cannot only show the sound field distribution in liquid and solid at different time moments, but also can be applied to non-transparent solid. In addition, it does not strictly require small residual stress of the sample. The sample can, therefore, be easily made. Because the acoustic field is obtained by indirect measurements, the recording can be affected by the after-shock of the receiving sensor and is prone to the influence of the direct wave of the liquid. Putting an aluminum plate into a liquid, we recorded the compression wave, shear wave and surface wave in the aluminum and, in the liquid we also recorded the direct wave and three head waves, which are directly coupled with the compression wave, shear wave and surface wave respectively. The recording clearly depicts the coupling relationship of the sound waves through the interface between the aluminum and the liquid. Putting a plexiglass into a liquid, we also recorded the sound waves in the plexiglass and the coupling relationship between the sound waves in the two mediums.

关键词： dynamic photoelastic technique Schlieren method sound wave visualization method

维普期刊数据库

sound GENERATION AND INTERACTIONS OF SHOCK waveS WITH ROWS OF VORTICES

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Transactions of Nanjing University of Aeronautics and Astronautics 2013年第3期30卷 276-281页

作者：许东洋关晖吴锤结 State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of Technology School of Aeronautics and Astronautics Dalian University of Technology Department of Mathematics &Physics PLA University of Science and Technology

Interactions of shock waves and rows of vortices are studied by solving the two-dimensional,compressible Euler equations with a fifth-order weighted essentially non-oscillatory finite difference *** a compressible flow the Mach number of the shock wave and vortex equals to 1.05 and 0.25,*** resulting flow field contains complex shock structures,such as multiple shock focusing and reflecting *** the meantime,sound waves are generated,interrupted and reformed when they touch the main and reflected shock waves.

关键词： shock wave vortex street composed of four vortices interaction sound wave

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Crack Detection by Optical Voice Recorder Based on Digital Holography

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Photonic Sensors 2019年第4期9卷 327-336页

作者： Gülhan USTABAŞKAYA Zehra SARAÇ Zonguldak Bülent Ecevit University Faculty of EngineeringDepartment of Electrical and Electronics EngineeringIncivezZonguldak 67100Turkey

The detection of crack on materials is an important issue in *** the contrary to conventional methods,such as manual inspection,sensor detection,and image processing techniques,a new simple method to detect the crack is proposed with optical voice recorder based on digital holography in this *** obtained with sound waves passing through the materials are recorded by using the digital holography *** behavior of the sound wave passing through the material,which is obtained from these holograms,gives image of *** this article,cracks in various materials are determined by the proposed new method,and crack images obtained with this new system are presented.

关键词： Crack detection sound wave digital holography material surface

Advances in Detection Methods for Invasive Pest Bactrocera dorsalis

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Plant Diseases and Pests 2014年第4期5卷 6-8,30页

作者： Liang Xueqiang Huang Lifei Jiang Jianjun Chen Hongsong Xie Qinhui Yang Lang Environmental Protection Branch of Nanning High-tech Industrial Development Zone Plant Protection Research Institute Guangxi Academy of Agricultural Sciences Guangxi Key Laboratory of Biology of Crop Pests and Diseases

Bactrocera dorsalis Hendel （Diptera： Tephritidae） is an invasive pest around the world. The paper summarizes biological and ecological characteristics of B, dorsalis, and reviews its detection methods from the aspects of morphological identification, acoustic detection and molecular detection, in order to provide a reference for further research and development of new detection methods. The hot issues in the study of B. dorsalis, such as ecological adaptation pattern, diffusion pathways and mechanisms, sustainable control measures, are also put forward in the paper.

关键词： Bactrocera dorsalis (Hendel) Detection method sound wave DNA Barcode

Mode Conversion and Brewster Law in Acoustics

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Mode Conversion and Brewster Law in Acoustics