The field emission properties of single-wall carbon nanotubes with purity higher than 70%,which were produced by dc arc discharge evaporation of a carbon electrode including 1% Fe catalyst in H2-Ar mixture gas was studied.The single-wall carbon nanotubes that were produced by this method possess high a ‘clean’ surface since the coexisting Fe catalyst nanoparticles can be completely eliminated by a two-step purification process.The field emission properties was verified by measuring the emission current density(J) versus the applied electric field(E), the corresponding Fowler-Nordheim(F-N) plot for the sample.Through looking at the emission photos, the uniformity of field emission is found to be excellent.

This paper presented a novel post-treatment method of He plasma,which could effectively improve the field emission characteristics of screen-printed CNTs cathodes. Notable changes in the surface morphologies of screen-printed CNTs cathodes were investigated by scanning electron micro scope (SEM) as the f unction of treatment by He plasma.The results showed the post-treated CNTs cathodes hold lower turn-on electric field,higher field emission current density,more emission sites,and better uniformity than those of untreated ones.

To study the form function and combustion characteristics of partially‐cut stick propellants, this paper derived and established the form function of this complex geometry propellant and analyzed the influence of cutting parameters on the form function. The analysis showed that partially‐cut stick propellants retain the high progressive combustion of multi‐aperture granular propellant, which is proportional to the distance between the notch and inversely proportional to the width of the notch. Based on this, partially‐cut stick propellants with different notches were prepared, and closed vessel tests were conducted. The experimental results showed that the notch had a significant effect on the combustion characteristics of the propellant. When there were notches, the wider the notch, the faster the pressure rise. The pressure in the closed vessel for stick propellants without notches rose the fastest. The burning rate of non‐notched or narrow‐notched fluctuated, while the burning rate of wide‐notched was stable. The dynamic vivacity data showed that the wider the notch, the more stable the change of the burning surface, and the combustion characteristic was closer to the granular propellant. Based on the analysis of form function and combustion characteristics, it is recommended that the notch width be 1 mm and the distance between notches on the same side should be the length of a granular propellant for the double‐base homogeneous 19‐perforated propellant studied in this paper.