• Materials Science
  • Published 1975

Completely positive maps on complex matrices

  title={Completely positive maps on complex matrices},
  author={M. D. Choi},
A porous graphite reservoir layer for retaining electrolyte within a fuel cell is improved by coating the pore surfaces of the reservoir layer with wettable, particulate amorphous carbon. Preferably the amorphous carbon particles are colloidal and have a mean pore size considerably smaller than the pore size of the body which they coat. This coated reservoir retains its hydrophilic properties for an extended period of time.