利用PIV方法测量半浮区液桥热毛细对流的速度场

利用PIV法对硅油液桥热毛细对流的定常速度场进行了实时测量。为了便于测量,液桥上桥端面采取了铜环中嵌透明材料的方法,从液桥的顶部进行观测。当液桥上下桥有温差时,热毛细对流出现;本实验对于不同上下桥的温差,对液桥横剖面内的速度场分别进行了测量,研究外加温差对于流场速度分布的影响;并且在液桥中取了几个典型横截面进行测量,以期对大Pr数液桥的定常速度场有比较全面的定量测量。此外,实验结果也可作为数值模拟计算结果的验证。     

Prime sequences for asynchronous pulse repetition interval agileradar

We propose the use of prime sequences in pulse repetition agile radar to increase the immunity of the radar to reconnaissance and deceptive jamming. The prime sequences are mapped into state agile mapped (SAM) sequences and are used to determine the pulse repetition interval (PRI) of the radar. We show that this produces a system with low mutual interference between radars and with a low probability of ambiguous range measurement resulting in good resistance to active deceptive jamming