Performance Analysis of Anti-CW Interference in MC-CDMA Systems

The multicarrier-code division multiple access (MC-CDMA),which is the combination of direct sequence CDMA (DS-CDMA) and orthogonal frequency division multiplexing (OFDM) techniques, offers various advantages over single-carrier CDMA system. Some of the advantages are that MC-CDMA systems possess can remove the intersymbol interference (ISI) and enhance narrow-band interference suppression capabilities. So the MC-CDMA technique becomes a focus in the field of mobile communication. The authors introduce the typical MC-CDMA system model, discuss the decision statisticalvariable in Rayleigh fading channel included the CW interference, and give the expressions of probability of error in uplink. An approach is proposed with Modified Equal Gain Combining (MEGC) to decrease the effect of CW interference. Theoretical analysis and numerical results show that the anti-CW interference performance of MC-CDMA system can be improved used the MEGC approach.     

光纤传感共振瑞利散射荧光法测定新疆黄芪中痕量砷

[目的]利用光纤传感共振瑞利散射荧光法测定中草药黄芪中痕量砷。[方法]将黄芪进行前处理,采用氢化物发生—催化,结合光纤传感,优化试验条件,共振瑞利散射光谱法测定砷含量。[结果]最佳试验条件为0.3 mol/L硫酸、0.9 mol/L Na BH4、0.2 mol/L Na BH4。方法学考察显示,该方法的RSD为6.9%,回收率为96%~105%。[结论]该方法较简单、易行、准确度高、稳定性好,值得推广应用。     

CdTe量子点作探针共振瑞利散射法测定鲑精蛋白

以巯基乙酸(thioglycolic acid,TGA)为稳定剂,在水相中合成水溶性的碲化镉量子点(CdTe QDs),采用荧光光谱、共振瑞利散射光谱法研究了CdTe QDs与鲑精蛋白(Salmine,Sal)的相互作用,研究结果表明:在pH=8的弱碱条件下,带负电的CdTe QDs与带正电的Sal通过静电引力及疏水作用力结合,形成粒径较大的结合物,这种结合物的形成导致共振瑞利散射(RRS)显著增强,同时CdTe QDs的荧光猝灭,在优化的实验条件下,散射光强度(ΔI)与Sal浓度呈现良好的线性关系,线性范围为0.016～2.4μg/mL,相关系数为0.9969,检出限为5.00ng/mL,研究了最佳反应条件和共存物质的影响,据此建立了一种以CdTe QDs作探针,RRS法测定Sal的新方法,同时讨论了CdTe QDs与Sal作用机理。