8～12μm波段折/反/衍混合坦克扫描物镜消热差设计

根据坦克扫描光学系统的要求,设计了一种工作于8～12μm波段,可识别2 000 m远坦克目标的折/反/衍射混合红外消热差光学系统。该系统采用新型的卡塞格林系统,其非球面主镜和次镜全部取代为球面,解决了卡塞格林系统大口径非球面主镜、次镜的高加工精度和装调难的问题;通过应用衍射元件独特的温度特性实现红外光学系统的无热化设计,设计的系统结构简单紧凑,口径大、焦距长、分辨率高,并且在-40～60℃的温度范围内成像质量接近衍射极限,满足坦克扫描系统的总体要求和像质要求。     

深亚微米SOC高压缩率EDT设计

EDT（embedded deterministictest）是目前最有效的针对大规模片上系统的嵌入式测试方法．与常规基于ATPG的DVT（Design For Testability）技术相比较，可以在保持相同缺陷覆盖率的情况下．大幅度降低测试成本，缩短测试时间，EDT的关键技术是解压缩器的算法设计。本文研究基于环形发生器的解压缩器设计．它不会对系统的逻辑核进行任何改动，如插入新的测试点或带来新的逻辑不确定态，可以获得40倍以上的压缩率．而且全部设计是基于标准的扫描／ATPG技术，可以非常方便的在SOC（system on chip）设计环境中实现。在最后部分，我们研究了采用环形发生器解压缩器，在不同容量的SOC系统的EDT设计结果。     

Non-monotonic lattice parameter variation with crystallite size in nanocrystalline solids

An anomalous dependence of the lattice parameter on the crystallite size of nanocrystalline ball-milled powders of metals was observed: lattice contraction followed by lattice expansion with decreasing crystallite size. These data were determined by application of detailed X-ray diffraction measurements. To this end the lattice parameters of the metals investigated – nickel, copper, iron and tungsten – were precisely determined by correcting for influences of stacking faults, in the face-centred cubic metals, as well as by correcting for instrument-related aberrations. The non-monotonic variation of the lattice constant was interpreted as the result of two competing mechanisms: interface-stress-induced contraction vs. expansion as a result of the stress field generated at the crystallite boundary due to the increased excess free volume in the crystallite boundary upon decreasing crystallite size.     

Pulse broadening factor as a criterion to assess nonlinear penalty of 40-Gbit/s RZ-DQPSK signals in dynamic transparent optical networks

The real-time scheduling and routing in dynamic transparent optical networks requires fast and accurate evaluation of transmission penalty caused by nonlinear kerr effects with different dispersion maps. However, the conventional method using nonlinear phase shift can only be applied to assess the nonlinear penalty with optimized dispersion maps. In this paper, we introduce pulse broadening factor into the approach and propose a novel method to accurately evaluate nonlinear penalty and numerically investigate the feasibility of our novel method in 40-Gb/s Return-to-Zero Differential Quadrature Phase-Shift Keying (RZ-DQPSK) systems. Simulation results show that our approach can achieve good evaluation performance even with non-optimized dispersion maps.     

SOLUTION OF TRANSIENT LAMINAR NATURAL CONVECTION IN A SQUARE CAVITY BY AN EXPLICIT FINITE ELEMENT SCHEME

This paper discusses the application of a finite element method based on the first-order projection scheme, which is an extension ofChorin's algorithm, to transient laminar natural convection in a square cavity. Results have been presented for a fluid of Prandtl number 0.71 in the Rayleigh number range of 10³-10⁶ in terms of the variation of vertical velocity component, nondimensional temperature, and average Nusselt number with time. Various features of the scheme that render it economical in terms of CPU time and storage requirements are discussed. The steady state results have been compared with benchmark solutions, and the agreement appears to be good.     

Surface-modified silicon nanowire anodes for lithium-ion batteries

Silicon nanowires with hydride, methyl and siloxane surfaces terminations were evaluated as anodes in lithium-ion half cells using LiPF₆ in EC/DMC electrolytes. Voltammetry, FT-IR and XPS analyses show hydride-terminated nanowires react with the electrolyte and methyl termination tends to passivate silicon surfaces. Silicon anodes pretreated with trimethoxymethylsilane show decreased lithium capacities similar to methylated anodes; however, the addition of 5% trimethoxymethylsilane as an electrolyte additive resulted in the formation of significantly more OPFx compounds while improving capacity retention relative to hydride-terminated nanowires (2348 mAh g⁻¹ at 15 cycles at C/10 rates). FTIR analysis show trimethoxymethylsilane additives covalently bond silicon surfaces and other SEI components. AFM nano-indentation tests also suggest the alkoxy silane additives in the electrolyte function as a binder to improve silicon's ability to withstand the large reversible volume changes. The results indicate silicon surface terminations play a key role in chemical and mechanical behaviors that control reversibility.     

Coupling-loss reduction of a vertically coupled microring resonator filter by spot-size-matched busline waveguides

To improve the input-output coupling loss of a vertically coupled microring resonator filter, we fabricated microring resonators on an antiresonant reflecting optical waveguide (ARROW) with a large spot size and on the rectangular busline waveguide with a spot-size transformer. The spot size and the tapered structure were optimally designed from the viewpoint of spot-size matching to single-mode fibers and the reduction of radiation loss. Clear dropping responses were demonstrated for the ARROW-based microring resonator filters, and the coupling loss was successfully reduced by 22 dB.     

基于Delphi的动态树型目录的设计与实现

在管理信息系统(MIS)的开发中,如何显示信息和提供方便直观的信息查询/修改方式是一项重要的任务。首先分析基于树型目录的信息显示和查询的特点,然后结合开发MIS的实践,给出动态树型目录在Delphi下的实现技术。     

用激光测速系统测试旋转流场

本文作者介绍了使用激光多普勒测速仪对轴流泵内部流场进行测试的方案 ,试验装置的布置及试验结果。