Application of Millimeter Wave in Verification of Scale Model Measurement for Radar Cross Section

According to the physical optic approximation, a physical scale factor is suggested for scale model measurement of radar cross section (RCS). By this factor, the models of radar targets can be tested at the same frequency as prototype. This is significant for the lack of experimental equipment required or the problem of frequency dependency of radar absorbing materials on the objects. For the purpose of further verification and comparison, millimeter-wave is used to measure the model at the wavelength scaling down proportionally to the prototype. And the measurements of the models are also carried out at microwave band (same working wavelength with prototype). The computed results from models agree well with the data by prototype itself.     

Novel Fault-Tolerant Decompression Method of Corrupted LZSS Files

Data compression and decompression have been widely applied in modern communication and data transmission fields. But how to decompress corrupted lossless compressed files is still a challenge. This paper presents an effective method to decompress corrupted LZSS files. It is achieved by utilizing source prior information and heuristic method. In this paper, we propose to use compression coding rules and grammar rules as the source prior information. Based on the prior information, we establish a mathematical model to detect error bits and estimate the rough range of the error bits. As for error correction, a heuristic method is developed to determine the accurate positions of error bits and correct the errors. The experimental results demonstrate that the proposed FTD method can achieve a correction rate of 96.45% for corrupted LZSS files when successfully decompressed. More importantly, the proposed method is a general model that can be applied to decompress various types of lossless compressed files of which the original files are natural language texts.     

移相120°单极倍频变换器研究

论述了移相120°单极倍频变换器研究的必要性,分析了移相120°单极倍频变换器的谐波、基波成分。分析及实验表明移相120°单极倍频电路有利于消除低次谐波、改善输出波形;并实现单/三相控制电路的通用。     

Room-temperature optically pumped InAs/GaAs quantum dots microdisk lasers on SiO2/Si chip

We report on room temperature continuous-wave optically pumped InAs/GaAs quantum dot whispering gallery mode microdisk lasers,heterogeneously integrated on silica/silicon chips.The microdisks are fabricated by photolithography and inductively coupled plasma etching.The lasing wavelength is approximately 1200 nm and the obtained lowest laser threshold is approximately 28μW.The experimental results show an approach of possible integrated Ⅲ-Ⅴ optical active materials on silica/silicon chip for low threshold WGM microdisk lasers.     

钢板厚度及混凝土强度对粘钢补强梁疲劳性能的影响

本文通过钢筋混凝土芯梁及粘贴钢板补强混凝土复合梁的疲劳试验，研究了它们在疲劳试验过程中载荷和加载线位移及跨中挠度的变化规律。同时，还探讨了混凝土强度、补强钢板厚度等因素对粘钢补强梁的疲劳性能影响。     

含裂隙含水层污染物生物降解数值方法

本文讨论了含裂隙介质地下水污染物输运与生物降解非线性方程组数值求解方法.方程含有对流项、扩散项、生长、死亡、吸附、解吸、趋化和孔隙与裂隙介质界面间的交换项的非线性偶合，使算法十分困难.本文讨论了无生化过程时的几种求解方法，数值结果表明：用三次迎风插值法对常见的对流项占优势，且场变量有较大梯度的问题较适用.在讨论有生化反应过程时，利用对流项与生化反应项的特征时间量级估算，给出了求生化过程作用子步的时间步长估算办法.用上述方法所得到的模拟结果与解析解、无化学反应和有化学反应的实测值对比，吻合很好     

龙滩碾压混凝土重力坝防渗结构研究--沥青混合料防渗结构

在调查分析国内外116座碾压混凝土坝基础上，论述碾压混凝土坝单独设置防渗结构的必要性。对调查的碾压混凝土坝的防渗结构归纳为三大类型，即：（1）刚性防渗结构；（2）柔性防渗结构；（3）联合防渗结构。在分析比较这三类防渗结构优缺点的基础上，首先推荐柔性防渗结构中的沥青混合料防渗结构作为龙滩碾压混凝土坝防渗结构。并对沥青混合料防渗结构的耐久性、环境污染、应用效果等进行充分论证；对防渗结构构造、防渗层的厚度和沥青混台料的类型作了分析和建议；对沥青混合料流变侧压力进行了计算；提出了沥青混合料防渗结构综合机械化施工方案和质量保证措施。     

A novel Ultra WideBand monopole antenna with band-notched characteristics

A simple and compact microstrip-fed Ultra WideBand(UWB) printed monopole antenna with band-notched characteristic is proposed in this paper.The antenna is composed of a square ring with a small strip bar,so that the antenna occupies about 7.69 GHz bandwidth covering 3.11～10.8 GHz with expected band rejection from 5.12 GHz to 5.87 GHz.A quasi-omnidirectional and quasi-sym-metrical radiation pattern is also obtained.This kind of band-notched UWB antenna requires no ex-ternal filters and thus greatly simplifie...     

Fabrication of field emission display prototype utilizing printed carbon nanotubes/nanofibers emitters

Carbon nanotubes/nanofibers (CNTs) used as emitters, diode-type field emission display (FED) prototypes of dot matrix and character images were fabricated by low-cost techniques and equipments, respectively. The technical development in the design and fabrication of the cathode, the anode, and the panel, is described. CNTs were produced by a simple, low-cost and easily-controllable thermal chemical vapor deposition. The cathode was prepared by the screen-printing method. The field emission characteristics were enhanced by a heat post-treatment in H₂ gas atmosphere. The panel structure was packaged by a vacuum fluorescent display-like process and vacuum-sealed through an exhaust glass tube. The fully-sealed CNTs FED (c-FED) showed good emission properties. The brightness of 600 cd/m² was achieved from the yellow phosphor at a relatively low applied electric field. The developed technology has a potential practical application in c-FED.     

光传输网规划中光缆芯数及光纤类型确定的影响因素

光传输网是电信网的基础,由于光缆线路系统的特殊性,决定了光传输网规划中光缆芯数及光纤类型的确定尤其重要。