吉林球粒陨石（H5）的高压声速实验研究

 叙述了以透明材料作窗口，用辐射法测量吉林陨石的高压声速的原理、实验技术和实验结果，实验压力范围为42.2~113.2 GPa，得到了吉林陨石的高压声速随冲击压力的变化关系，并由此判断出吉林陨石在约65 GPa时发生相变。     

Underwater optical generation of sound: Oblique incidence

This paper addresses itself to the problem of thermoacoustic generation by an obliquely incident laser beam in a body of water. Far-field directivity pattern of thermoacoustic source (TS) has been studied analytically and numerically. Our study suggests the possibility of getting highly directional sound beams in a simple configuration.     

穿孔板在切向流条件下非线性效应的理论与实验研究

流过声衬表面的切向流和高声压级的声场对于穿孔板共振结构的声学特性有这非常显著的影响。本文从波涡相互作用机制出发,发展了一种旨在研究矩形穿孔板在切向流条件下非线性效应的离散涡模型。同时用双传声器法测量了不同几何参数的穿孔板的声阻抗随偏流速度及声压级的变化情况。将本文的实验与理论结果进行了对比分析,对比的结果表明本文的实验与理论结果符合良好。     

The Mixing Effect of Glycylglycine with KCl, KBr, and Na2SO4 from Volumetric and Viscometric Investigations at 298.15 K

The mixing effect of a simple peptide such as glycylglycine, in the presence of aqueous electrolytes, has been studied by examining their volumetric and viscometric behavior. The increase in the apparent molar properties of both glycylglycine and electrolytes is attributed to the interactions present among cation, anion, the head groups of the peptide, and the peptide bond. Simple equations are developed to account for such interactions with a view to correlate apparent molar properties of glycylglycine and electrolyte in their aqueous mixtures. Transfer properties of both glycylglycine and electrolyte are investigated in order to understand the changes in the property of one component by the addition of another. These interactions are also supported by viscosity data, for which a simple model is developed to correlate the variation in viscosities with composition of a component.     

一种快速收敛的符号回归常数模盲均衡算法

为了加快符号回归常数模算法(SRCMA)的收敛速度,本文提出了一种适合于BPSK信号 的快速算法。该算法用新的误差函数替代SRCMA中的误差函数,新误差函数针对BPSK信号而 设计。新算法采用分数间隔均衡模型,有效地加快了SRCMA算法的收敛速度。水声信道仿真实验 表明,该算法性能稳定,收敛速度快,适用于快速变化信道的盲均衡和水声通信数据的实时恢复。     

声场分离技术及其在近场声全息中的应用

提出空间声场分离技术，突破了近场声全息（NAH）的应用局限.它们的局限在于全息面一侧的声场必须是自由声场，即要求所有的声源必须位于另一侧.利用波数域内的波场外推理论及声压的标量叠加原理，建立起声场分离技术的双全息面实现方法，利用波数域内的Euler公式及粒子振速的矢量叠加原理，建立起该技术的单全息面实现方法.该技术的一个突出优点是在具有背景噪声的全息测量情况下, 可以消除背景噪声对全息变换结果的影响.理论的推导表明该技术方法的正确性，而仿真算例和实验则显示该技术的可行性和有效性. 关键词： 声全息 波数域 声场分离 背景噪声     

Spatial sound resolution of an interpolated HRIR library

The paper evaluates the human directional resolution of virtual sound sources synthesised with the aid of a generalised head related impulse response (HRIR) library, i.e., an HRIR library measured using a dummy head and torso. The original HRIR set is first expanded using linear interpolation, and then directional resolution measurements are performed for playback through headphones. These results are compared to the results obtained using loudspeakers as sound sources in an anechoic chamber. Directional resolution is the ability of listeners to distinguish two closely-spaced sound sources alternately playing the same signal. Experiments show that two sound sources with insufficient spacing appear as a single source to the listener. Directional resolution for small azimuth changes is relatively high for both virtual and real sound sources. Most test subjects have no problem resolving two sound sources only 5° apart. Compared to real sound sources, detecting changes in elevation of virtual sound sources is much less accurate, which may be the main drawback of using a generalised HRIR library.     

航空发动机环形燃烧室噪声总声级多元回归模型研究

本文利用航空发动机环行燃烧室测试数据 ,采用线性回归和非线性回归两种方法分别得到了燃烧室噪声总声级和燃烧噪声峰值及峰值频率的拟合模型 ,并利用线性回归模型由燃烧室外部测量结果估算燃烧室内部总声级 ,所提供的噪声数据可供研究发动机燃烧室结构完整性和可靠性时参考 .     

对5通路3/2环绕声系统缺陷的分析

本文利用环绕声重发的声像定位理论，对一种受到重视、很可能将被国际上广泛应用的通用环绕声系统—5通路3／2系统的声像特性进行了分析，并对系统进行了声像定位实验．理论和实验结果表明，按目前的信号馈给方式，系统可在倾听者前方产生稳定而明晰的声像；但在侧向和后方只能产生模糊和不稳定的声像（扬声器方向除外）；将别是在侧向，存在着一个声像的死区，并且对侧向和后方声像来说，听音区域片不宽阔，因而作为一种通用的系统，虽然将其用作伴随图像的重发时，可获得较好的效果；但用作不伴随图像的重发时，系统并不能很好地再观原声场的空间感。由于系统存在这种不容忽视的缺陷，文中着重强调应设法在这方面对系统加以改进     

头盔的声学性能测试与分析

本文设计了使用自相关函数以测试混响声衰变速度、自功率谱以测试插入损失的方法，用于头盔的回声与隔声效果分析．结果表明，这一方法物理概念明确，测试简单，可以定量地说明头盔的声学性能可能存在的问题，可望用于头盔的声学性能客观测试与分析方法的建立．