The dtft provides a frequency-domain representation of discrete-time signals and lti discrete-time systems Because of the convergence condition, in many cases. the dtft of a sequence may not exist as a result. it is not possible to make use of such frequency-domain characterization in these cases Copyright C 2001, S K. Mitra
草鱼出血病病毒感染鱼肾(C1k)单层细胞后,产生明显的细胞病变,其繁殖周期为 2一3天。病毒增殖的上升期在感染后的12—48小时。28°下,当感染复数(Multiplicity of Infection简称mo为0.05pfu/ce11时病毒滴价可达1.78×101PU/ml,不同 温度(25°℃、28°℃、30C)下通气培养,测定病毒滴价略有差异