互换定理 meaning in English

theory of reciprocity

In theory , firstly , the theorectical considerations on soft x - ray are discussed . secondly , the conclusion is obtained based on the applying the lorentz reciprocity theorem , which demonstrates that equivalence of brazing exit and grazing incidence methods
在理论研究方面，首先讨论了软x射线荧光产生的原子物理相关理论；其次根据洛伦兹互换定理，得出了掠出射和掠入射两种荧光分析理论具有互换性的结论。