试谈应崇福院士的科研思想方法

正应崇福院士将他的科研思想与方法归纳为六个字:观察、分析、总结,令人深受启发,获益匪浅。我自毕业就跟着应先生工作直到退休,不但直接跟随先生从事科研工作,作为他的助手,还参与了由先生主持的有关学科方向、组织机构调整以及人员安排等科研组织管理方面的工作,使我对应先生的科研思想与方法有了更多的机会去了解和体会。我给大家总结了几点应先生的科研思想和方法:     

Thickness Measurement of a Film on a Substrate by Low-Frequency Ultrasound

We describe a new simple technique for the low-frequency ultrasonic thickness measurement of an air-backed soft thin layer attached on a hard substrate of finite thickness throug-h the frequency-shifts of the substrate resonances by the substrate-side insonification. A plane compressive wave impinging normally on the substrate surface from a liquid is studied. Low frequency here means an interrogating acoustical wave frequency of less than half of the ‘half-wavelength resonance frequency‘ of the thin layer depending on the acoustical impedance ratio of the coating to the substrate. Equations for the frequency-shifts are derived and solved by the Newton iterative method and the Taylor expansion method, respectively, indicating satisfactory agreement within the range of interest of thickness ratio of the thin layer to the substrate for a polymer-aluminium structure. An experimental setup is constructed to verify the validity of the technique.