A novel ultracompact two-mode-interference wavelength division multiplexer for 1.5-/spl mu/m operation

A novel ultracompact 2/spl times/2 wavelength division multiplexer (WDM) for 1.55-/spl mu/m operation based on highly dispersive two-mode interference (TMI) was designed, theoretically modeled, and verified using a finite-difference-time-domain (FDTD) method. A two-moded waveguide assisted with a dispersive tooth-shaped grating provided a mode-dependent reflection band of central wavelength at 1.55 /spl mu/m. The wavelengths of 1538 and 1572 nm that were at the band edges and had the lowest reflection losses and relatively high dispersion were selected for wavelength multiplexing. The result showed that the wavelengths were separated by grating dispersion in a coupler length of 75 /spl mu/m which was much shorter than the required length of 1.1 mm in a regular TMI multiplexer of no grating. Insertion loss of about 1.7 dB and channel contrast of about 12 dB were achieved.     

基于Multisim7.0软件平台的电子电路设计型实验研究

介绍了EDA(电子设计自动化)技术中Multisim7.0软件平台的功能特点.利用EDA技术进行设计性实验的研究与开发,是改革传统电子电路实验教学模式的有效途径,能帮助学生掌握最先进的电子电路设计方法和技能.结合EDA技术在电子电路设计型实验中的应用实例分析,阐明了利用Multisim7.0软件平台进行电子电路设计的优越性,其方便的更改电路和元器件参数的能力,使得能够更快更好地进行电子电路设计与仿真分析,同时缩短设计电路的时间,因而是一种全新的培养学生实际动手能力的有效工具.     

山区建筑的结构设计注意点及探讨——永安一中教学楼设计心得

本文通过工程实例分析了山区建筑的结构设计特点,并提出了结构设计中应注意的问题。     

液体静力称量法液体密度测量及其不确定度评定

介绍了液体静力称量法测量液体密度的原理并给出液体密度的计算公式,对影响测量结果的各种因素作了详细的分析,并对各个分量所引入的不确定度进行了数值计算,得出液体密度最终测量结果的合成标准不确定度.     

基于IPC的直流电机控制实验装置设计

介绍了工业控制计算机（IPC）在工业自动化领域中对直流机控制的应用，以工控机作为实验平台。设计了IPC测控系统之一的直流机测控子系统的实验装置，叙述了如何用IPC进行直流机转速的脉冲调宽式（PWM）控制，并通过软件实现在多任务实时操作系统（MROS）申直流机的速度测控和速度曲线绘制。     

CMOS电路中抗Latch-up的保护环结构研究

闩锁是CMOS集成电路中的一种寄生效应,这种PNPN结构一旦被触发,从电源到地会产生大电流,导致整个芯片的失效。针对芯片在实际测试中发现的闩锁问题,介绍了闩锁的测试方法,并且利用软件Tsuprem4和Medici模拟整个失效过程,在对2类保护环(多子环/少子环)作用的分析,以及各种保护结构的模拟基础之上,通过对比触发电压和电流,得到一种最优的抗Latch up版图设计方法,通过进一步的流片、测试,解决了芯片中的闩锁失效问题,验证了这种结构的有效性。     

吹填粉细砂筑堤实践与研究

岳阳长江干堤是我国第一大河重要堤防,具有重要的战略地位。江南垸堤段每到汛期,堤身散浸,堤后管涌、海底浸不断,根据各方面比选决定采用吹填粉细砂筑堤进行治理。文章对大堤设计断面及排水方案进行拟定并对渗流稳定、堤坡稳定及地震反应进行分析,认为所拟定的加固断面可行,投资省。     

Testing multi-characteristic product capability indices

Recently, studies associated with testing the quality and performance of each process for a product with multi-characteristics are proposed more often. However, most studies are limited to discussing one single type of quality characteristic. Practically, a multi-characteristic product is potentially composed of three types: smaller-the-better, larger-the-better, and nominal-the-best. In this paper, we propose an integrated product capability index which considers these three different types of quality characteristics. According to the theory of testing hypothesis, we develop a testing procedure for the product capability index to judge whether the process capabilities of total quality characteristics meet the customers’ demands. In addition, the relationship between the product capability index and the yield of the entire product will be introduced. Finally, an example is provided as a practical application.     

Tunnel stability and arching effects during tunneling in soft clayey soil

A series of centrifuge model tests and numerical simulations of these tests were carried out to investigate the surface settlement troughs, excess pore water pressure generation, tunnel stability and arching effects that develop during tunneling in soft clayey soil. The two methods were found to provide consistent results of the surface settlement troughs, excess pore water generation, and the overload factors at collapse for both single and parallel tunneling. The arching ratio describes the evolution of the arching effects on the soil mass surrounding tunnels and can be derived from the numerical analysis. The boundaries of the arching zones for both single tunneling and parallel tunneling were determined. In addition, the boundaries of the positive and negative arching zones were also proposed.     

Anodising potential influence on well-ordered nanostructures formed by anodisation of aluminium in sulphuric acid

High-density structures with relatively well-ordered nanopore arrays have been obtained by the self-ordering growth of nanopores occurring during anodisation of aluminium in sulphuric acid. The resulting array of well-ordered nanopores strongly depends on an applied voltage of anodising, temperature and a procedure of synthesis. Regular arranged hexagonal arrays on aluminium with a relatively uniform pore diameter, interpore distance, and depth of pores exceeding 90 μm, can be formed by the self-ordering two-step anodising at 1 °C. The interpore distance and the pore diameter were evaluated on anodised aluminium layers obtained at different cell potentials ranging from 15 to 25 V. The detailed analyses of their uniformity were performed from SEM images. The analysis of a pore arrangement defects was made from SEM top view images taken on samples anodised at various cell potentials. The defect maps, known as Delaunay triangulations, of the arrangement of about 1000 pores were constructed for different applied anodising potentials. The percentage of pores that are not six-fold coordinated by the neighbouring pores indicates the percentage of defected surface.