This review aims at comprehensively presenting the state-of-the-art of Ultrasound-Assisted Drying (UAD).

UAD represents a promising hybrid drying technique that enhances drying rate and energy efficiency while preserving the quality of the materials being dried. However, in accordance to literature, the limited knowledge and capacity of ultrasonic equipment still prevent this technology from being used in practical industrial applications.

The first part briefly described the fundamentals of ultrasound. One major challenge of developing UAD is its multidisciplinary nature; the intention is to extend our knowledge on acoustic science in order to understand the role of ultrasound in drying enhancement.

The second part encompasses the latest UAD studies; they are focused on four research subjects:

1) UAD equipment

2) Influence of ultrasound on drying performance

3) Parametric analyses

4) Impacts of ultrasound on the quality of dried materials

Progress has been made in the last two decades, but to date, researchers are not fully capable of explaining certain contradictory observations such as those presented herein. This review synthesizes the published results and analyzes them with respect to the specific drying conditions; then, some explanations are suggested.

这篇综述旨在全面介绍超声辅助干燥（UAD）的最新技术。

UAD代表了一种有前途的混合干燥技术，该技术可提高干燥速率和能源效率，同时保留待干燥物料的质量。然而，根据文献，超声设备的有限知识和能力仍然阻止该技术在实际工业应用中使用。

第一部分简要介绍了超声波的基本原理。发展UAD的一项主要挑战是其多学科性质。目的是扩展我们在声学科学方面的知识，以了解超声在增强干燥中的作用。

第二部分包括最新的UAD研究；他们专注于四个研究主题：

1）UAD设备

2）超声波对干燥性能的影响

3）参数分析

4）超声波对干燥物料质量的影响

在过去的二十年中已经取得了进展，但是迄今为止，研究人员还没有完全能够解释某些矛盾的观察结果的能力，例如本文提出的观察结果。该综述综合了已发表的结果，并针对特定的干燥条件进行了分析；然后，提出一些解释。