Multi-field coupling thermo-acoustic radiation using free-standing nano-thin films in a static magnetic field

Abstract

Thermo-acoustic radiation from nano-thin film has been widely reported these years. In this paper, a static magnetic field is introduced to enhance the acoustic power in the multi-field thermo-acoustic generation. The coupled thermo-acoustic system in a static magnetic field shares the same acoustical unit with very few additional components. In the presence of a static magnetic field, thin-film vibration is excited instead of being still in the classical thermo-acoustic system. Not surprisingly, a steady magnetic field has very little impact on the thermo-acoustic generation system when a constant amplitude sinusoidal current is introduced. The oscillation perpendicular to the nano-thin film is driven by the electromagnetic force. The system response of thermo-acoustics and magneto-acoustics can be generally matched when suitable parameters are introduced. The acoustical pressure output can be significantly improved in the presence of a static magnetic field although more electrical input power should be provided in the multi-field thermo-acoustic system. Evidently, the coupled multi-field acoustical system is able to handle more electrical power input and the power input can be more easily dissipated relatively. The results show that the acoustic response of this new multi-filed coupled system can be significantly improved as compared to the classical system without magnetic effects.     

特殊状况下的体育馆建声设计

某体育馆是一所刚竣工但没有进行声学装修的体育馆。针对其声学上的主要缺陷恰当地采取了一些特殊声学措施，使该馆基本满足了体育馆使用的声学要求。     

基于矢量阵测量的局部近场全息技术研究

统计最优近场声全息技术是通过全息面上测量声压的线性叠加来反演重建面上的声学量,可以从理论上克服基于傅氏变换的近场声全息技术的局限性。针对水中圆柱体的噪声源识别问题,采用声压和质点振速测量来进行声全息计算,推导了基于振速测量的统计最优柱面近场声全息技术的重建公式。利用所编制的程序进行了仿真验证,最后设计矢量水听器进行水中全息实验,验证了该方法的可行性和准确性,实验结果表明,该技术在水中柱形声源辐射声场的噪声源识别和定位中有着明显的优势。     

国家大剧院音乐厅音质主观评价

对音乐厅的音质评价一直是国际声学界关注的重点课题之一,因其涉及内容广泛,包含较多主观因素等原因,一直没有形成系统有效的评价体系.综合运用了多种方法对音乐厅音质进行了评价,以期得到较为全面和可信的音质评价结果,同时也是对今后音乐厅音质设计和评价体系的有益探索.     

基于FBG对的低加速度灵敏度拖曳声纳阵水听器

拖曳声纳阵列要求水听器在进行变速运动时不影响对水声压力信号的正常探测,这就要求水听器具有很高的抗加速度能力.为此介绍一种利用光纤光栅设计制造的对加速度不敏感而对水声压力信号具有高灵敏度的光纤水听器的实验研究结果.研制的光纤水听器声压灵敏度约为-140 dBrad/μPa,在25～6 300 Hz频率范围内具有平坦的声压...     

Integration of acoustical information in the perception of impacted sound sources: The role of information accuracy and exploitability.

Sound sources are perceived by integrating information from multiple acoustical features. The factors influencing the integration of information are largely unknown. We measured how the perceptual weighting of different features varies with the accuracy of information and with a listener’s ability to exploit it. Participants judged the hardness of two objects whose interaction generates an impact sound: a hammer and a sounding object. In a first discrimination experiment, trained listeners focused on the most accurate information, although with greater difficulty when perceiving the hammer. We inferred a limited exploitability for the most accurate hammer-hardness information. In a second rating experiment, listeners focused on the most accurate information only when estimating sounding-object hardness. In a third rating experiment, we synthesized sounds by independently manipulating source properties that covaried in Experiments 1 and 2: sounding-object hardness and impact properties. Sounding-object hardness perception relied on the most accurate acoustical information, whereas impact-properties influenced more strongly hammer hardness perception. Overall, perceptual weight increased with the accuracy of acoustical information, although information that was not easily exploited was perceptually secondary, even if accurate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

浅析不同尺度下观演建筑的设计策略

本文通过对上海大剧院与某中学报告厅的分析,从造型、功能组合、流线、音质设计六个方面进行了对比,从而加深了观演建筑较为全面、深入地认识,探讨了在不同尺度下观演建筑设计策略的异同。     

一种提高热声发动机压比的"声学变压器"

针对目前低温热声制冷机的驱动压比比较低的现状,提出了一种连接在热声发动机与制冷机之间的一种变压装置.热声发动机产生的压力波动在经过此变压器进行"变压"后,波动压力幅值大幅升高.对此方案设计了原理性的实验,表明声波在经过此变压器之后压力幅值能够提高3倍左右,充分证明此变压器具有大幅度提高压力幅值的能力.     

吴江高等职业技术学院报告厅声学设计

吴江市高等职业技术学院报告厅是一个椭圆形的平面，针对可能出现的声聚焦问题，声学设计中提出的技术处理方法是有效的，现场测量和主观调查表明声学设计取得了满意的音质效果。     

渐变型声指向耦合器中声场的计算

提出一种新的计算波导中场分布的方法。该方法基于有限元法(FEM)，但采用人工透射边界，称之为有限元—人工透射边界法。并用渐变型声指向耦合器中表面声波导二维声场的计算实例说明该方法的实用性。