说明：  一本对于学习超声系统很有帮助的书，可以方便的查阅和理解。书中对于各类的超声例如医学超声，工业超声都有说明。
(A book that is very helpful for the learning of ultrasonic systems can be easily consulted and understood. All kinds of ultrasound, such as medical ultrasound and industrial ultrasound are described in the book.)