Carrier concentration 1 Dust 1 Dust emission 1 Dust extinctions 1 Electron density measurement 1 Electrons 1 Galaxies 1 Galaxies: individual: small Magellanic cloud 1 Hydrogen 1 ISM: individual object: DEM s103, NGC 346, ITK 25 1 ISM: individual objects 1 ISM: individual objects: DEM S103, NGC 346, ITK 25 ISM: supernova remnants 1 Pulsars 1 Shock waves 1 Shock-waves 1 Spitzer 1 Supernova remnants 1 Supernovae 1 dust, extinction 1 galaxies: individual: Small Magellanic Cloud 1 shock waves 1