The effect of preheating, test-piece thickness and coupling agents on the electric properties and the mechanical properties of the materials have been specially studied.
试验结果表明，模压前合理的预热可以显著地提高酚醛塑料的电性能及力学性能；
2
Condensate from the first-effect calandria is used for preheating the feed.
一效列管换热器中出来的冷凝液被用来预热进料。
3
The effect of preheating intensity on engine performance has analysed, and the parameters for evaluating preheating intensity are suggested as well.