Closely packed dense frequency selective surface

In order to realize wideband filtering properties of frequency selective surface （FSS）, FSS of closely packed elements is presented. The Y loop elements are chosen as the graphics elements. Based on the spectral domain method, the frequency response is analyzed for different incident angles and polarizations. The result of the numerical analysis shows that the dense FSS has wide passband with better independence of angle and polarization.     

A Spatiotemporal-Chaos-Based Cryptosystem Taking Advantage of Both Synchronous and Self-Synchronizing Schemes

Two-dimensional one-way coupled map lattices are used for cryptography where multiple space units producechaotic outputs in parallel. One of the outputs plays the role of driving for synchronization of the decryption sys-tem while the others perform the function of information encoding. With this separation of functions the receivercan establish a self-checking and self-correction mechanism, and enjoys the advantages of both synchronous andself-synchronizing schemes. A comparison between the present system with the system of advanced encryptionstandard (AES) is presented in the aspect of channel noise influence. Numerical investigations show that oursystem is much stronger than AES against channel noise perturbations, and thus can be better used for securecommunications with large channel noise.     

超声速多普勒效应

 多普勒效应是一种重要的物理现象.当声源相对观察者以低于声速的速度运动时,听到的声频变高或变低.这是人们所熟知的.     

HIRFL-CSRm纵向随机冷却-槽形滤波冷却模拟研究

 通过Fokker Planck方程,对拟在HIRFL-CSRm上建造的纵向槽形滤波器（notch filter）的冷却机理进行了研究,得出了冷却原理及冷却时间的表达式,并对影响冷却时间和冷却效果的因素进行了模拟和讨论,模拟结果表明,噪信比越小,冷却时间越短,冷却效果越好;带宽越宽冷却越快。该研究为具体纵向冷却系统的设计和优化提供了依据。     

Rescaling Symmetry Flow of the Kadomtsev--Petviashvili Hierarchy

We present a new symmetry flow of the Kadomtsev-Petviashvili (KP) hierarchy, which origins from the rescaling of whole “multi-time“ valuables. This flow describes the deformation of solutions of the KP hierarchy with respect to a noncommutative parameter. It is shown that the introduced rescaling symmetry flow does not commute with the ordinary evolution flows of the KP hierarchy, but commutes with the evolution flows with respect to slow-variables.     

高频地波雷达下的多目标跟踪数据处理

根据高频地波雷达监测海上低速移动目标的要求及该类雷达的特点,提出了一种与高频地波雷达目标跟踪相适应的多目标跟踪数据处理方案。在该方案中对BTC(bayes tracking confirm)方法与BTT(bayes tracking termination)方法进行了改进,解决了上述两种方法在高频地波雷达实际应用中存在的问题。提出了贝叶斯准则与次数判定相结合的跟踪起始和终结方法。模拟结果表明,该方案能够稳定、有效地实现高频地波雷达密集回波下的多目标跟踪。     

一种边缘提取的图像分割方法

图像分析技术从广义上来讲 ,是指从图像中提取有用的数据或其它信息。图像分割是图像分析技术的重要手段 ,在前人的理论基础上经过实验提出了一种边缘提取的图像分割方法———行扫描空间带通滤波法。该方法在电视图像的自动跟踪识别中取得了很好的效果 ,是一种较为可取的图像分割方法     

Taub-NUT时空视界附近自旋场的热力学量

利用Wentzel-Kramers-Brillouin近似计算了Taub-NUT时空事件视界附近自旋为1/2，1，3/2，2等无质量场的熵密度、压强和能量密度.结果表明，自旋场附近的热力学量不仅具有与平直时空相同的主导项，还多了两项自旋依赖的附加项. 关键词： Taub-NUT时空 自旋场 热力学量     

X射线探测器图像的恢复研究

图像退化是引起X射线探测器图像质量下降的主要原因。图像恢复,可以提高系统的分辨率和对比度灵敏度。通过对射线成像系统图像退化的分析,介绍了反滤波信号恢复方法,并提出了一种近似恢复算法,该算法将反滤波恢复近似为除法运算的恢复。给出了恢复前后的图像及标准差的对比,实验结果表明了该算法的有效性。     

丝阵Z箍缩实验1维X光辐射功率分布

 在Angara-5-1联合实验中，利用条纹像机和光纤阵列实现时间分辨和1维空间分辨，得到了丝阵条纹像，观察到丝阵负载箍缩区X光辐射的1维轴向空间分布信息随时间的演化过程，考察了内爆的同步性和均匀性。通过对比不同结构负载内爆等离子体X光1维时空分布信息，发现由于内层等离子体对磁流体瑞利-泰勒不稳定性的抑制作用，(40+20)根双层钨丝阵比60根单层钨丝阵的内爆轴向同步性好，产生的X光辐射功率高；由于负载存在弯曲、断丝、扭曲等现象，(60+30)根双层钨丝阵比90根单层钨丝阵的轴向同步优势不明显；轴向同步性好与辐射功率高之间存在相关性；辐射波形前沿较快时，X光功率较高。