I. Sound Generation Sound comes from the vibration of an object and is the sound wave produced by the vibration of an object. In the research of acoustic technology, we call the object that can produce sound sound source. Sound source is no...

Noise refers to the sound produced by the vocal body when it vibrates irregularly. Sound is produced by the vibration of an object and propagates in the form of waves in a certain medium, such as solid, liquid and gas. Noise pollution is us...

I. Comments on the Industry in 2018 1. Major Policies On September 7, 2018, the legislative plan of the 13th Standing Committee of the National Peoples Congress was promulgated. The Law of the Peoples Republic of China on the Prevention and...

Beijing Yunlang Environmental Protection Engineering Co., Ltd. Thanks to all the staff for their efforts and hard work in 2018! Thank you for your strong support and warm care from all customers, friends and leaders of all walks of life. In...