1/f Noise QWIPs and nBn detectors

The low-frequency noise is a ubiquitous phenomenon and the spectral power density of this fluctuation process is inversely proportional to the frequency of the signal. We have measured the 1/f noise of a 640 × 512 pixel quantum well infrared photodetector (QWIP) focal plane array (FPA) with 6.2 μm peak wavelength. Our experimental observations show that this QWIP FPA’s 1/f noise corner frequency is about 0.1 mHz. With this kind of low frequency stability, QWIPs could unveil a new class of infrared applications that have never been imagined before. Furthermore, we present the results from a similar 1/f noise measurement of bulk InAsSb absorber (lattice matched to GaSb substrate) nBn detector array with 4.0 μm cutoff wavelength.     

Fabrication of type-II InAs/GaSb superlattice long-wavelength infrared focal plane arrays

In this paper, we present an InAs/GaSb type-II superlattice (SL) with the M-structure for the fabrication of a long-wavelength (10 μm range) infrared (LWIR) focal plane arrays (FPA), which are grown by molecular beam epitaxy (MBE). The M-structure is named for the shape of the band alignment while the AlSb layer is inserted into the GaSb layer of InAs/GaSb SL. A 320 × 256 LWIR FPA has been fabricated with low surface leakage and high R₀A product of FPA pixels by using anodic sulfide and SiO₂ physical passivation. Experiment results show that the devices passivated with anodic sulfide obviously have higher R₀A than the un-sulphurized one. The 50% cutoff wavelength of the LWIR FPA is 9.1 μm, and the R₀A is 224 Ω cm² with the average detectivity of 2.3 × 10¹⁰ cm Hz^1/2 W⁻¹.     

导弹发射姿态测量方法研究

针对导弹发射姿态测量问题,提出采用高速摄像机通过斜瞄和平瞄姿态测量方法求解导弹中轴线俯仰角和方位角,仿真典型导弹起飞段近距离姿态测量,分析两种测量方法对导弹飞行姿态测量精度和适用性。仿真结果表明:平瞄和斜瞄姿态测量方法,测量误差在0.2°以内。斜瞄方式使用更便捷,通用性好。平瞄方式测量精度高,数据处理方法、机械结构相对简单,在适合的应用场合优势明显。此分析方法、分析结果为姿态测量方法选取和研究等提供一种可行的途径,也可为其它运动目标的姿态测量提供借鉴。     

Co3O4纳米晶催化氧化甲烷的理论研究：C-H键活化的晶面效应及活性中心

甲烷是一种在自然界中大量存在的原材料,在取代原油和合成重要化工产品等许多领域具有潜在的应用价值. 然而,由于CH₄中C-H键的键能特别大（约~4.5 eV）,如何实现甲烷的绿色有效转化在化学化工领域仍然是一个挑战. 本文采用密度泛函理论对Co₃O₄（001）和（011）晶面活化甲烷C-H键的机理进行了理论研究,得到了如下结论：（1） CH₄的C-H键在Co₃O₄晶面的解离具有很高的活性,只需要克服大约1 eV的能垒;（2）与Co^2＋相连的Co-O离子对是CH₄活化的活性位点,其中两个带正负电荷的离子对C-H解离起着协同作用,帮助产生Co-CH₃和O-H物种;（3）（011）面的反应活性明显大于（001）面,与实验的观察一致. 本文的计算结果表明,Co₃O₄纳米晶面对CH₄中C-H键的活化表现出明显的晶面效应和结构敏感效应,Co-O离子对活性中心对于活化惰性的C-H键发挥了关键作用.     

LOBSTER: Local orbital projections,atomic charges,and chemical-bonding analysis from projector-augmented-wave-based density-functional theory

We present an update on recently developed methodology and functionality in the computer program Local Orbital Basis Suite Toward Electronic-Structure Reconstruction (LOBSTER) for chemical-bonding analysis in periodic systems. LOBSTER is based on an analytic projection from projector-augmented wave (PAW) density-functional theory (DFT) computations (Maintz et al., J. Comput. Chem. 2013 , 34, 2557), reconstructing chemical information in terms of local, auxiliary atomic orbitals and thereby opening the output of PAW-based DFT codes to chemical interpretation. We demonstrate how LOBSTER has been improved by taking into account time-reversal symmetry, thereby speeding up the DFT and LOBSTER calculations by a factor of 2. Over the recent years, the functionalities have also been continually expanded, including accurate projected densities of states (DOSs), crystal orbital Hamilton population (COHP) analysis, atomic and orbital charges, gross populations, and the recently introduced k -dependent COHP. The software is offered free-of-charge for non-commercial research.     

内容计费及其技术路线

基于传统语音业务利润率下降的现实,阐述了内容服务价值链的形成原因和组成,并提出建设一套能够为电信运营商所用、所管、所利的内容计费平台的必要性.最后,概要说明了内容计费平台的建设原则和两种技术方案与适用条件.     

基于平面通量展开的三维Pin by Pin输运SP3计算

基于Pin by Pin输运SP3计算是下一代反应堆物理计算方法中一个重要的研究方向.节块法一般采用高阶通量和中子源展开以适应较大的节块尺寸,因此对于Pin by Pin计算来说效率偏低.由于反应堆堆芯不均匀性更多发生在径向,本文提出一种径向基于二维平面通量展开结合轴向常规节块法的综合方法进行三维Pin by Pin输...     

基于高性能包处理架构VPP的带内网络遥测系统

面向高性能虚拟网络转发架构及设备VPP,通过重构数据平面的流水线处理模块,设计了基于矢量数据包处理技术的带内网络遥测方案,并在此基础上通过引入源路由机制引导遥测报文走向,实现了一种带内全网遥测的扩展案例.最后,基于虚拟机组网方式,搭建网络拓扑并进行网络性能评测.实验结果表明,该遥测系统能够在0.13 ms精度的遥测时间...     

光斜入射时偏振器作用的表述

对偏振器特性的分析表明,当光斜入射时,振动方向与偏振器透光轴不平行的光也能通过偏振器,只要该方向与系统光轴与透光轴构成的平面平行。提出了透光平面的概念。利用欧拉角表示光波坐标系和偏振器坐标系之间的变换,得到透过偏振器后偏振光的振动方向及其大小的数学表述,给出了简化表达式及其使用条件。表达式具有一般性,可以直接使用。     

智能光网络(ASON)的关键技术及发展策略

在市场和网络建设的驱动下,智能光网络(ASON)作为一种新型的智能光传送网,得到了迅速的发展.首先介绍ASON的总体结构及其构件,重点介绍ASON中涉及到的关键技术,包含传送平面、控制平面和管理平面.并且提出电信运营商在构建新一代光传输网络时可以采取的相应策略.