宽带电力线通信系统的电磁干扰评估

提出了电力线电磁干扰的评估方法,可以获得符合FCC标准的PLC功率限值。首先基于计算电磁学理论,建立PLC传输模型和电磁辐射模型,并对PLC的电磁辐射进行近场测试;然后根据测试结果调整PLC传输模型参数,使得PLC空间的电磁辐射计算值与测试值趋于一致。最后计算观察点处的电磁辐射。可用于评测PLC与室内短波无线电、超宽带无线通信等系统的电磁共存性,并制定功率限值标准,实现绿色电磁环境：     

The trefoil protein TFF1 is bound to MUC5AC in humangastric mucosa

The trefoil protein TFF1 is expressed principally in the superficial cells of the gastric mucosa. It is a small protein and forms homo- and hetero-dimers via a disulphide bond through Cys58 which is located three amino acids from the C terminus. TFF1 is co-expressed with the secreted mucin MUC5AC in superficial cells of the gastric mucosa suggesting that it could be involved in the packaging or function of gastric mucus. We have previously shown that TFF1 co-sediments with mucin glycoproteins on caesium chloride gradients. To extend this observation we have now used gel filtration under physiological conditions, immunoprecipitation and Western transfer analysis to characterise the interaction of TFF1 with gastric mucin glycoproteins. We show that TFF1 co-elutes with MUC5AC but not MUC6 on gel filtration and that immunoprecipitation and Western transfer analysis confirms that TFF1 interacts with MUC5AC. We also demonstrate that the TFF1 dimer is the predominant molecular form bound to MUC5AC. Salt and chelators of divalent cations such as EDTA and EGTA disrupted the TFF1- MUC5AC interaction and increased the degradation of MUC5AC, whereas calcium increased the amount of TFF1 bound to MUC5AC. These data support the contention that TFF1 is pivotal in the packaging and function of human gastric mucusa.Received 24 March 2004; received after revision 14 May 2004; accepted 7 June 2004