基于回波预处理和相参积累的C&I干扰抑制算法

C&I(chopping and interleaving)干扰是一种针对线性调频(linear frequency modulation, LFM)雷达的典型干扰样式, 干扰子信号调频斜率与雷达发射信号相同, 利用信号处理工具分离真实回波与干扰信号难度较大。针对该问题, 以LFM相参雷达抗自卫式C&I干扰为背景, 提出基于回波预处理和相参积累的干扰抑制算法。根据估计的回波时延, 设置距离窗截取受干扰回波段, 在此基础上, 通过对回波预处理, 改变不同重复周期内假目标的快时间位置分布, 通过相参积累实现干扰抑制。仿真试验表明, 所提算法能够有效抑制强干扰背景下的C&I干扰, 干扰抑制后真实目标检测概率大幅提高, 虚假目标数量明显减少。     

Quantum decoherence and the approach to equilibrium (II)

In a previous paper [Hemmo, M & Shenker, O (2003). Quantum decoherence and the approach to equilibrium I. Philosophy of Science, 70, 330–358] we discussed a recent proposal by Albert [(2000). Time and chance. Cambridge, MA: Harvard University Press. Chapter 7] to recover thermodynamics on a purely dynamical basis, using the quantum theory of the collapse of the quantum state of [Ghirardi, G, Rimini, A and Weber, T., (1986). Unified dynamics for microscopic and macroscopic systems. Physical Review, D 34, 470–479]. We proposed an alternative way to explain thermodynamics within no collapse interpretations of quantum mechanics. In this paper some difficulties faced by both approaches are discussed and solved: the spin echo experiments, and the problem of extremely light gases. In these contexts, we point out several ways in which the above quantum mechanical approaches as well as some other classical approaches to the foundations of statistical mechanics may be distinguished experimentally.     

The Nature of Light and Twentieth Century Experimental Physics

In the popular literature of physics the electromagnetic field isoften treated as though it has an intrinsic particle nature. When thetheory is examined carefully, quantum theory only makes the weakerrequirement that the emission and absorption of light are restricted todiscrete amounts of energy. There are very few realizable experiments inoptics for which the classical Maxwell theory and the quantum theorymake a different prediction. I discuss some of these experiments with anemphasis on the distinction between what the experiments tell us aboutthe measurement process, and what they tell us about the nature of thelight field.     

NSRL-XAFS光束线弧矢聚焦双晶单色器设计

针对XAFS光束线能量动态扫描的实验特点，介绍了弧矢聚焦双晶单色器的物理设计：包括晶体光学结构、性能参数计算、晶体热载分析和弧矢弯曲原理．弧矢缩比选择为1：4．88，水平接收角由原来的1mrad拓宽到3mrad，在不改变基本配置的情况下，获得了样品上束癍缩小、光子通量高达半个量级以上的增益．     

非谐振多光子过程的原子压缩效应

考虑非谐振情况下的多光子跃迁过程,在ｋ≥ｒ⊥,ｒ∥的条件下,利用绝热近似方法,由线性Ｆｏｋｋｅｒ－Ｐｌａｎｃｋ方程导出此过程的原子压缩表示式。     

反式- 4- [4''''- (N,N-二丁基氨基 )苯乙烯基 ] - N-甲基吡啶对甲基苯磺酸盐的合成、表征及光学性质研究

摘要：合成了一种新的有机染料，反式-4-[4′-(N，N-二丁基氨基)苯乙烯基]-N-甲基吡啶对甲基苯磺酸盐，并通过元素分析、电喷雾质谱、热重分析以及红外等现代化分析手段进行表征，并对其紫外-可见电子光谱、荧光光谱等线性光学性质进行初步研究．     

微波测量中的频域特性分析

分析了微波测量中回波信号的时间变量函数 ,确定了时间变量函数和频率变量函数之间的变换关系     

单光子发射断层成像散射解析模型的快速算法

为校正单光子发射断层成像(SPECT)中Compton散射的影响,对投影过程进行了解析建模计算。对相机参数进行预计算形成查找表,结合初始放射源活度和散射媒质分布计算得到投影中的原发光子和一次散射光子分布。用数论方法计算查找表中的高维数值积分,使计算速度提高。分别用解析建模方法和Monte-Carlo程序对均匀模型和胸腔模型进行投影计算,比较其相对误差、归一化方差和计算时间。结果表明:解析建模方法的精度与Monte-Carlo方法相当,而计算速度快8倍,可以满足临床需求。     

光子晶体的制备及其应用

介绍了光子晶体的基本概念、主要特征及其制备方法和应用前景。