Search

Frictional wear between the armature and the rails directly affects the armature-rails contact condition, thereby affecting the service life and launch efficiency of the electromagnetic rail launcher. In order to explore the influence of temperature on the frictional wear of electromagnetic rail launcher, the source of heat load on the launcher is analyzed, a frictional wear model under the effect of temperature is established and the effect of temperature on the wear between armature and rail is analyzed. Using the finite element method, the pulse forming network is used to power the launcher, the contact resistance variation curve with time is found out, the 3D finite element calculation model is established considering the electromagnetic field-temperature field-stress field, etc., and the data related to the armature wear amount in the two states considering the temperature field and not considering the temperature field are compared and analyzed. The results show that with the armature movement, the temperature of the contact surface of the armature-rails gradually increases, the elastic modulus and hardness of the material in the contact area decrease, and the change trends of the wear volume and wear rate of the armature in the two states are the same. The maximum wear rate of the armature when considering the temperature field is 1.15 mm3/ms, which is 1.2 times of the maximum wear rate of the armature without considering the temperature field.

The development of highly selective homogeneous electron transfer reagents is highly desirable for synthetic chemistry. An isolable spirosilole tetra-anion described in this paper has been proved to be a promising soluble electron transfer reagent. The reduction of octaphenyl-1,1′-spirobisilole (1) with lithium resulted in the formation of the isolable spirosilole tetra-anion in good yield. The tetra-anion (2) has been characterized by nuclear magnetic resonance (NMR) and cleanly underwent electron transfer reactions with dioxygen, carbonyl groups, and transition metal halides to yield reduction products with the regeneration of 1.