Each particle is covered with an insulative oxide film which contains 0.3 to 0.8% of {HEAD ~ oxygen} by {TAIL ~ weight} based on the particle 
Each particle is covered with an insulative oxide film which contains 0.3 to 0.8 % of { HEAD ~ oxygen } by { TAIL ~ weight } based on the particle
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH