Chemical compositions and optical properties of HfOxNy thin films at different substrate temperatures

High-k HfO_xN_y thin films have been grown by radio frequency (rf) reactive sputtering of metal Hf target in N₂/Ar/O₂ ambient at different substrate temperatures. The chemical compositions of the films have been investigated as a function of substrate temperature by X-ray photoelectron spectroscopy (XPS). XPS measurements showed that nitrogen concentration increases with an increase in substrate temperature. Room-temperature spectroscopic ellipsometry (SE) with photon energy 0.75–6.5 eV was used to investigate the optical properties of the films. SE results demonstrated that refractive index n increases with an increase in substrate temperature. Based on TL parameters which were obtained from the best fit results used in a simulation of the measured spectra, meanwhile, we conclude that the energy band gap (E_g) decreases with an increase in substrate temperature.     

量子阱红外探测器能带结构的计算

利用电子波在阱与垒的界面上的反射及干涉效应，计算了量子阱红外探测器(QWIP)的能带结构，并对其适用性进行了分析和讨论。通过与K-P模型比较发现，本方法对计算较宽势阱(阱宽大于4nm)的量子阱结构的电子态适合。在垒宽和阱宽不变条件下，用两种方法计算得到的AlGaAs／GaAs量子阱材料中Al组分x与吸收峰值波长λp的关系曲线基本相同。结果说明，在较宽的范围内，本方法对QWIP能带结构的计算是适用且简便的。     

L波段窄脉宽500W固态功放组件的设计

介绍了作者研制的应用于固态雷达发射机上的L波段500W固态功放组件的工作原理、用途及其主要技术指标。描述了功放组件的设计过程和测试结果。该功放组件在窄脉宽条件下实现了快速上升沿,性能优良,工作稳定可靠。     

Numerical modelling for scattering of waves in three-dimensional cracked material

In this paper, a mathematical model is proposed for the problem of the scattering of plane waves in a three-dimensional cracked materials. Instead of obtaining closed-form solutions as in conventional theoretical analysis methods, this approach, called the Equivalent Nodal Force (ENF) method formulates the mechanical effects of cracks as an equivalent nodal force in a numerical procedure, and physically translates cracked material into an equivalent continuous one. Several mechanical relations between waves and cracks are evident from this method. Also the results of several numerical calculations are presented and these are compared with those obtained by the conventional methods.     

Phase equilibria in InAsSbP quaternary alloys grown by liquid phase epitaxy

The quaternary alloy InAs_1−x−ySb_xP_y, lattice-matched to InAs, is a promising material for the production of infrared light sources for the detection of gases in the 2–4 μm region of the spectrum. In this work, thermodynamic phase equilibrium calculations have been carried out to determine the compositions required for liquid phase epitaxial growth and the extent of the miscibility gap in the solid material. For high band gap materials, the desired growth temperature is found to be intermediate between a low temperature required to grow P-rich solids and higher temperatures required to avoidspinodal decomposition. Conventional LPE growth at an intermediate temperature of 583°C is found to produce good material with high luminescence efficiency and excellent optical characteristics. Problems with phosphorus loss from the melt are also discussed and lower growth temperatures are found to considerably reduce this problem. Growth in the metastable region between the binodal and spinodal lines has been achieved with the production of phosphorus-rich solids with concentrations up to y = 0.445.     

Boundary trend of α1/(α1 +α2) phase region at lower Cu side in Al-Zn-Cu system

The range of miscibility gap above 300 ℃ at low Cu side in Al-Cu-Zn ternary system was obtained by EPMA of the designed alloys and diffusion-couples treated for equilibrium. The results about the boundary trend of the α1 / (α1 α2 ) phase region was obtained. The α1 / (α1 α2 ) boundary moves towards the lower Zn side with the increase of Cu content. The results are opposite to traditional phase diagrams obtained by experiments, but consistent with recent thermodynamic calculations.     

安钢宽板坯连铸机达产实践

分析了安钢宽板坯连铸机在热试车期间出现的生产问题,总结出制约生产主要因素,制定针对性措施,使该连铸机在较短时间内实现达产创效.     

企业网络隔离方案探讨

分析威胁网络安全的主要因素及网络隔离对网络风险的防范作用。根据几种网络隔离技术的特点和企业网的应用需求，提出企业网中3个典型网络边界上的网络隔离方案，展望网闸隔离技术在企业网中的应用前景。     

Ultrasonic measurement of the inter-electrode gap in electrochemical machining

During the process of electrochemical machining the dependency of the inter-electrode gap with time and process parameters can be used to determine process characteristics and to define the shape of the workpiece surface relative to the tool surface. Defining process variables to map out the required gap-time function requires the use of time-consuming iterative trials. In-line monitoring of the gap would enable process control and tool to workpiece transfer characteristics to be achieved (for ideal conditions) without the requirement to generate such parameter maps. This work explores the use of ultrasound applied as a passive, non-intrusive, in-line gap measurement system for ECM. The accuracy of this technique was confirmed through correspondence between the generated gap-time and current time data and theoretical models applicable to ideal conditions. Gap measurements are also used to demonstrate and quantify the degree of departure from ideal behaviour for an In718/chloride system as the electrolyte flow rate is reduced from 16 to 4 l min⁻¹. The monitoring of the gap size has also been shown to be effective when determining shape convergence under ideal conditions, for the example case of a 2D sinusoidal profile.     

高速并行调制解调器中差错控制方法

本文简单介绍了适合高速并行调制解调器中差错控制的Reed-Solomon编码，提出了适合DSP软件实现的一整套的RS码的编码、译码实用方法，并对该编、译码法采用数字信号处理器TMS320C5410b进行仿真，对其性能与传统方法进行了对比。