基于声光效应的相干光探测方法的研究

基于布拉格衍射和相干光探测原理,分析了入射光和衍射光的特性及数学关系,讨论了如何利用声光偏转器实现信号处理的方法.从改善空间相干光探测效率出发,提出一种将空间光经声光衍射后注入保偏光纤的处理方法,克服了传统相干探测中光偏振态难控制的缺点,减小了外界环境对信号光和参考光合路的影响,降低了光学系统的调整环节中的难度,有效地解决了相干光探测中光束对准和偏振光的保持问题.实验证明,在保证一定的耦合光孔径和激光注入效率条件下,将空间光注入保偏光纤,削弱了背景光对合路产生的影响,使信号光和参考光偏振态和传输方向能更好保持,极大改善了空间相干光探测效率,提高了光电探测信噪比.     

Equivalent doping profile transformation: a new analytical method to predict breakdown voltage of the composite pn junction

This paper describes a new analytical method called the equivalent doping profile of a composite p–n junction, that is, a simplified diffused junction with a linear gradient G _L on the diffused side and a constant concentration N _sub on the substrate. The analytical results for various combinations of the substrate doping concentration and the diffused side gradient levels agree well with the numerical analysis, showing the validity of the method presented here.     

Carrier type- and concentration-dependent absorption and photoluminescence of ZnO films doped with different Na contents

The electrical and optical properties of zinc oxide (ZnO) films doped with different Na contents and grown by pulsed laser deposition were investigated. Hall measurements witnessed the conductivity conversion from n-type to p-type with targeted Na doping content increased up to more than 1%. The photoluminescence intensity first decreased as the targeted Na content increased to 1%, while non-degraded and even enhanced PL intensity was observed in p-type ZnO:Na_0.02 film. This photoluminescence enhancement was ascribed to enhanced radiative recombination with more acceptor (Na_Zn) introduced. The band-gap shift of ZnO:Na_x films was related to the variation of carrier type and concentration. Band-gap shrinkage was adopted to explain the carrier type- and concentration-dependent band-gap shift of ZnO:Na_x films.     

Origin and depositional model of deep-water lacustrine sandstone deposits in the 7th and 6th members of the Yanchang Formation (Late Triassic), Binchang area, Ordos Basin, China

Sandstones attributed to different lacustrine sediment gravity flows are present in the 7th and 6th members of the Yanchang Formation in the Ordos Basin, China. These differences in their origins led to different sandstone distributions which control the scale and connectivity of oil and gas reservoirs. Numerous cores and outcrops were analysed to understand the origins of these sandstones. The main origin of these sandstones was analysed by statistical methods, and well logging data were used to study their vertical and horizontal distributions. Results show that the sandstones in the study area accumulated via sandy debris flows, turbidity currents and slumping, and sandy debris flows predominate. The sandstone associated with a single event is characteristically small in scale and exhibits poor lateral continuity. However, as a result of multiple events that stacked gravity flow-related sandstones atop one another, sandstones are extensive overall, as illustrated in the cross section and isopach maps. Finally, a depositional model was developed in which sandy debris flows predominated and various other types of small-scale gravity flows occurred frequently, resulting in extensive deposition of sand bodies across a large area.     

电子辐照下碳膜中氢原子行为的研究

本文通过共振核反应与红外吸收两种实验方法,对用PECVD法淀积的非晶碳膜中氢原子在不同剂量电子辐照下的行为,进行了深入的研究.不同剂量的电子辐照,使碳膜样品中的氢含量大小及氢原子的存在方式等有不同程度的变化.     

延迟锁定环路的大步进快速捕获

本文提出一种新的延迟锁定环路的大步进快速捕获方法，主要解决目前尚未很好解决的低信噪比长序列伪随机码的快速捕获问题。文中讨论了在步进快速捕捕获延迟锁定环路的原理与实现，分析了这种环路的平均捕获时间，解扩相关器的输出成分及大步进搜索时的虚警与检测概率。     

Propagating eigenmodes for plane waves in a uniaxial bianisotropicmedium and reflection from a planar interface

A time-harmonic electromagnetic plane wave propagating in a uniaxial bianisotropic medium is considered. Forward- and backward-propagating eigenmodes are identified, together with their dispersion equations. The eigenmodes consist of two pairs with different phase velocities, and the two components of each pair correspond to the forward and backward modes. The propagating modes are used to calculate the reflection coefficient matrix at an interface between a vacuum and a uniaxial bianisotropic half-space. Numerical results for such a reflection are presented as a function of the direction of the optical axis     

The closeness for {NBU} and {NWU}

In this note an n mutually independent unit coherent system is considered. Using the minimal path method, it is proved that if every unit lifetime distribution belongs to {NBU} (which is a class of new better than used), the system lifetime distribution belongs to {NBU} also. Finally, by using an example, it is proposed that {NWU} (which is a class of new worse than used) is not closed.     

非平面接地静磁表面波延迟线的优化设计＊

本文改进了非平面接地静磁表面波延迟线器件模型,并首次采用递归二次规划对器件结构进行了优化设计,为静磁波器件设计提供了新途径。