Application of thermal stress model to paint removal by Q-switched Nd:YAG laser

In this paper, we demonstrate that thermal stress is the main mechanism in the process of paint removal by Q-switched Nd：YAG laser （λ = 1064 nm, τ = 10 ns）. A theoretical model ofpaint removal by short-pulse laser is established from the perspective of thermal stress. Thermal stress is generated by thermal expansion, and the temperatures of different samples are calculated according to the one-dimensional （1D） heat conduction equation. The theoretical cleaning threshold can be obtained by comparing thermal stress with the adhesion of paint, and the theoretical damage threshold is obtained by calculating the temperature. Moreover, the theoretical calculations are verified by experimental results. It is shown that the thermal stress model of the laser cleaning is very useful to choose the appropriate laser fluence in the practical applications of paint removal by Q-switched Nd： YAG laser because our model can validly balance the efficiency of laser cleaning and the safety of the substrate.     

基于物理与美术平行发展史的 学科融合教学模式研究

物理和美术是人类文明成果的两种表现形式, 虽各有特点, 但追求的本质是相同的, 都在各自的领域 里对自然和社会进行细致地观察和创新性地描述. 物理与美术共同的主题是时间和空间, 诸多内容是基于对称与 不对称之间的相互影响. 通过在教学中融入物理与美术的平行发展历程以及共通点, 探索出一条学科融合文理贯 通的新的教学改革模式