The electron transport behavior of polymer-derived amorphous silicon oxycarbonitride ceramics is studied by measuring their temperature-dependent electrical conductivities. The experimental results are analyzed using theoretical models. The results reveal that the materials exhibit three conduction mechanisms: conduction in extended states  conduction in band tails  and conduction in localized states. Particularly  it is found that in a low-temperature regime  the conduction of the materials follows a band tail hopping mechanism  rather than the previously assumed variable range hopping mechanism. The results also reveal that energy gaps such as EC-E F and EC-EA decrease with increasing pyrolysis temperature. 2009 The American Ceramic Society.  

The  J/Ψ  hadronic  decays  involving  2(π+π-)π°and  2(K+K-)  final  states  are  investigated  by  using  the  sample  of  2.5  *  10~6  J/Ψ's  which  were  obtained  from  the  BES  detector  at  BEPC  in  the  first  half  of  1990.  Some  signals  such  as  ω(782)  φ(1020)  f2(1270)  f2'(1525)  θ/f2(1720)  b1(1235)  and  a2(1320)  have  been  found  and  measured  the  mass  width  and  branching  fraction  of  reasonance  states.  The  results  are  agreement  with  the  world  average  values.  The  ratio  of  Br(J/Ψ  →  ω  f2(1270))/Br(J/Ψ→ρ°a2°)  shows  that  doubly  OZI  violating  effects  play  a  role  in  the  J/Ψ  →  ω  f2(1270)  f2(1270)  →  π+π-  are  given  in  the  first  time:  x  =  0.99  ±  0.29  Y  =  -0.24  ±  0.17  Z1  =  0.90  ±  0.57  Z2  =  0.56  ±  0.22.