多孔材料的吸声机理和影响吸声性能的因素、共振吸声结构分类与吸声原理

1、噪声的评价量 当某一频率的纯音和1000Hz的纯音听起来同 样响时,这时1000Hz的纯音的声压级就定义 为该待定声音的响度级。响度级的符号为L ,单位为方(phon) 对各个频率的声音作这样的试听比较,得出 达到同样响度级时频率与声压级的关系曲线 ,通常称为等响曲线

1、环境噪声影响评价工作程序和内容

《噪声污染控制工程》课程PPT教学课件（讲稿）第一章 绪论、第二章 声波的基本性质及其传播规律（1/2）

43. 1 Introduction 43.2 Amplifiers 43.3 Oscillators 43.4 Multipliers

45.1Introduction 45.2 Background Discussion Modeling as a Transfer Function. Some Issues Involved i

47.1 Introduction 47.2 SAW Material Properties 47.3 Basic Filter Specifications 47.4 SAW Transducer Modeling The SAW Superposition Impulse Response Transducer

49.1 Introduction 49.2 Mechanical Characteristics Applications. Structure of Ferroelectric and Piezoelectric Materials 49.3 Ferroelectric Materials K. F.Etzold Electrical Characteristics

51.1 Introduction 51.2 Equation of State 51.3 Effect of Crystal Point Group on 51.4 Geometric Corrections and Elastoresistance Tensor 51.5 Multivalley Semiconductors 51.6 Longitudinal Piezoresistivity II, and Maximum Sensitivity

53.1 Introduction Terry P. Orlando 53.2 General Electromagnetic Properties Massachusetts Institute of 53.3 Superconducting Electronics Technology 53.4 Types of Superconductors 53.1 Introduction The fundamental idea behind all of superconductorsu' properties is that superconductivity is quantum