研究了MUD-RAS系统(the system combined multi-user diversity with receive antennaselection)的容量.首先推导了MUD-RAS系统的等效单用户容量界,并分析了等效单用户系统分析法的局限性,即当用户数较大时,等效单用户容量界和实际容量存在较大的偏差;然后推导了MUD-RAS的另一个容量上界——多用户最大天线矩容量界的表达式.仿真结果表明,当用户数较大时,所给出的多用户最大天线矩容量界比等效单用户容量界更接近系统的实际容量.
The formation and qualification of redox sites in transition metal oxides are always the active fields related to electronics, catalysis, sensors, and energy-storage units. In the present study, the temperature dependence of thermal reduction of MoO3 was surveyed at the range of 350℃ to 750℃. Upon reduction, the formed redox species characterized by EPR spectroscopy are the MoVion and superoxide anion radical (O2-) when the reduction was induced at the optimal temperature of 300-350℃. When heating-up from 350℃, the EPR signals started to decline in amplitude. The signals in the range of 400-450℃ decreased to half of that at 350℃, and then to zero at ~600℃. Further treatment at even higher temperature or prolonged heating time at 500℃ caused more reduction and more free electrons were released to the MoO3 bulk, which results in a delocalized means similar to the antiferromagnetic coupling. These data herein are helpful to prepare and study the metal-oxide catalysts.
