《潮起潮落》的音乐逻辑与诗情画意

音乐与诗歌都是人类生活体验的自然流露和内心情感的自我表达;音乐是流动的诗歌意象链。英语诗歌《潮起潮落》的听觉艺术特征诉说了它本身自在的音乐逻辑:模音、节拍、旋律与曲式等方面,这种音乐逻辑助成了其生动的诗情画意。     

基于互联网+声测的重大交通事故一体化快速救援系统设计

设计的快速救援系统通过声信号的特征识别确认产生交通事故后,自动启动交通事故定位和自动报警系统,然后通过事故现场救援平台、救援中心指挥平台、辅助救援平台、应急救援预案系统等构建的一体化重大交通事故快速救援技术平台,实现广域综合信息和资源在救援平台的指挥下快速的、有组织的、全方位的共享共用,形成快速救援的技术能力。其中一体化平台中,设计的事故现场快速勘测系统和快速救援预案系统,为事故现场及时有效地鉴定和整个快速救援的系统优化提供了技术方案。     

Prediction of hydrodynamic noise of open cavity flow

In this paper, the hydrodynamically generated noise by the flow over an open cavity is studied. First, aeroacoustic theories and computational aeroacoustic (CAA) methodologies are reviewed in light of hydrodynamic acoustics, based on which, a hybrid method is presented. In the coupling procedure, the unsteady cavity flow field is computed using large-eddy simulation (LES), while the radiated sound is calculated by the Ffowcs Williams-Hawkings (FW-H) acoustic analogy with acoustic source terms extracted from the time-dependent solutions of the unsteady flow. The hybrid LES-FW-H acoustic analogy method is tested with an open cavity flow at Mach number of 0.006 and Reynolds number of 10⁵. Following the reflection theorem of Powell, the contributions from different source terms are quantified, and the terms involving wall-pressure fluctuations are found to account for most of the radiated intensity. The radiation field is investigated in the frequency domain. For the longitudinal direction, the sound propagates with a dominant radiation downstream the cavity in the near-field and a flatter directivity in the far-field, while for the spanwise direction, the acoustic waves have a similar propagation along +z and −z directions, with no visible directivity.     

音乐厅声学的一些新观点

总结2018年IOA声学会议上提出的音乐厅声学新观点和新问题,主要包括对低音比、墙面扩散和定义新的声学参数等问题的讨论,并简要介绍厅堂空间感动态响应性这一新的评价参数。     

Science Letters： New solutions of shear waves in piezoelectric cubic crystals

Acoustic wave propagation in piezoelectric crystals of classes?43m and 23 is studied. The crystals Tl3VS4 and Tl3TaSe4 (43m) of the Chalcogenide family and the crystal Bi12TiO20 (23) possess strong piezoelectric effect. Because the surface Bleustein-Gulyaev waves cannot exist in piezoelectric cubic crystals, it was concluded that new solutions for shear-horizontal surface acoustic waves (SH-SAWs) are found in the monocrystals using different electrical boundary conditions such as electri- cally “short” and “open” free-surfaces for the unique [101] direction of wave propagation. For the crystal Tl3TaSe4 with coefficient of electromechanical coupling (CEMC) Ke2=e2/(C×g)～1/3, the phase velocity Vph for the new SH-SAWs can be calculated with the following formula: Vph=(Va Vt)/2, where Vt is the speed of bulk SH-wave, Vt=Vt4(1 Ke2)1/2, Va=aKVt4, aK=2[Ke(1 Ke2)1/2-Ke2]1/2, and Vt4=(C44/ρ)1/2. It was found that the CEMC K2 evaluation for Tl3TaSe4 gave the value of K2=2(Vf–Vm)/Vf～0.047 (～4.7%), where Vf～848 m/s and Vm~828 m/s are the new-SAW velocities for the free and metallized surfaces, respectively. This high value of K2(Tl3TaSe4) is significantly greater than K2(Tl3VS4)～3% and about five times that of K2(Bi12TiO20).     

远场模式反演声波阻尼区域的一种数值解法

研究了时间调和的声波反散射问题,利用散射波的远场模式反演阻尼边界条件中的边界。应用单层位势来逼近散射波,最终把反散射问题转化为一个最优化问题,应用Levenberg—Marquardt算法求解。给出的数值例子说明了该反演方法是可行和有效的。     

衡阳方言单字调实验研究

文章旨在从语音实验出发,系统地描述湖南衡阳方言单字的声调系统。其结果与前人描述基本一致,即衡阳方言共有6个单字调,分别是阴平(45)、阳平(11)、上声(33)、阴去(24)、阳去(213)、入声(22)。     

城市旅游声景观优化策略研究

旅游体验是全方位的感知过程,以听觉感知为代表的城市旅游声景观在城市旅游发展的过程中同样不可忽视。生态学强调人与声音以及环境间的关系,以此为出发点可以揭示城市旅游声景观物理属性与环境属性的特点与构成,在此基础上对自然与人文声景观的设计及后期声景观的管理、运营提出切实可行的优化策略。     

下颌元音构音运动定量测量的实验研究

本研究采用单因素重复测量实验设计,探讨下颌不同构音位置以及不同位置间转换与F1及相关参数的关系,寻找能定量测量下颌精细分级运动以及转换运动能力的声学敏感参数.实验结果显示:(1)第一共振峰(F1)是反映下颌不同构音位置的敏感参数,验证下颌存在下颌上位、下颌半开位、下颌下位三种基本构音运动模式,为定量评估下颌精细分级构音运动能力提供依据.(2)"阿姨"和"衣蛾"的下颌转换斜率Jk和下颌转换幅度Jd能检测下颌精细分级转换运动能力,是定量评估诊断下颌精细分级转换运动障碍的敏感参数,可以为下颌构音运动障碍治疗方案的制定提供客观依据和指导.     

表面声阻抗近似局域k-k关系的实验研究

利用石棉多孔材料对表面声阻抗近似局域k-k关系进行了实验研究,通过最小频率分辨率分别为0.25Hz、0.5Hz和1Hz的理论和实验值的对比研究发现理论值与实验值相互吻合,从实验上很好地验证了表面声阻抗近似局域k-k关系的正确性.