In this paper we show the preliminary evidence that the formation of @entity23812 depends on the electrical conductivity of porous materials. Porous nano y- @entity16773 was chosen as the base material, and it was filled with @entity505 of different allotropes (commercial @entity15583 , @entity17244 , @entity505 nanotubes and home-made ordered mesoporous @entity505 ) by a mechanical mixing method. The positron lifetime and Doppler broadening of the annihilation radiation were measured for these composites. In the pure y- @entity16773 sample, there are two long positron lifetime components   3 (3.5 ns) and   4 (101.3 ns) with intensities of 1.0% and 24.6%, which indicates the formation and annihilation of @entity23812 in small and large pores, respectively. In the @entity505 filled y- @entity16773 samples, the longest lifetime   4 and its intensity I4 both show a continuous decrease with increasing @entity505 content. The Doppler broadening S parameter shows a similar tendency to   4 and I4. This suggests that @entity505 has a quenching effect on @entity23812 and also inhibits the formation of @entity23812 . Among these four @entity505 allotropes, @entity505 nanotubes have the strongest quenching and inhibition effect, while @entity15583 has the weakest effect. A detailed study further reveals that the decreasing rate of   4 and I4 as well as the S parameter depend on the electrical conductivity of the @entity505 filled y- @entity16773 and also the specific surface area of the filled @entity505 . Our results suggest that the formation and annihilation of @entity23812 are strongly affected by the electrical conductivity of the materials.

Effects of electrical conductivity on the formation and annihilation of XXXX in porous materials.

@entity16773 :: ('CHEBI:30192', 'Chemical') :: ['Al2O3'] @entity15583 :: ('MESH:D006108', 'Chemical') :: ['graphite'] @entity17244 :: ('MESH:D053260', 'Chemical') :: ['carbon black'] @entity23812 :: ('CHEBI:30224', 'Chemical') :: ['positronium'] @entity505 :: ('MESH:D002244', 'Chemical') :: ['carbon']
@entity23812 :: (CHEBI:30224,Chemical) :: ['positronium']
