实时图象处理中的图象存贮体的设计

图象存贮体是图象处理系统中必不可少的核心部件之一。它实现图象数据的接收、发送和存贮等功能,同时作为高速设备与低速设备之间的缓冲环节,以满足对图象处理系统多方面的要求。本文着重介绍实时图象处理系统中图象存贮体的设计及其工作原理,同时提供了它与计算机之间的DMA数据交换方式。     

紫外反射镜的研制

随着紫外大功率准分子激光器的发展,金属反射镜已不能满足要求,所以必须研制低损耗的全介质反射镜。本文描述了波长350nm(XeF)、308nm(XeCl)、248nm(KrF)和193nm(ArF)四种准分子激光反射镜的制备技术,其反射率分别达到99.7％、99.5％ 、98％和96％。在波长308nm,反射镜的激光破坏阈值达8J/cm~2以上。     

我国涉外企业避税与反避税问题探讨—兼议由于外汇调剂导致的外商避税

本文从产生国际避税的一般原因出发,结合我国涉外企业税法及会计制度的现状,具体分析了我国涉外企业避税的若干形式,最后提出了反避税的若干对策,以规范我国涉外企业的纳税行为,维护我国的主权和经济利益。     

Chemical Corrosion of Liquid-Phase Sintered SiC in Acidic/Alkaline Solutions Part 1. Corrosion in HNO<Subscript>3</Subscript> Solution

The corrosion behavior of the liquid-phase sintered SiC (LPS-SiC) was studied by dipping in 3.53 mol/L HNO₃ aqueous solution at room temperature and 70 °C, respectively. The weight loss, strength reduction and morphology evolution of the SiC specimens during corroding were revealed and also the chemical corrosion process and mechanism of the SiC specimens in the acidic solution were clarified. The results show that the corrosion of the LPS-SiC specimens in the HNO₃ solution is selective. The SiC particles are almost free from corrosion, but the secondary phases of BaAl₂Si₂O₈ (BAS) and Y₂Si₂O₇ are corroded via an acid-alkali neutralization reaction. BAS has a higher corrosion rate than Y₂Si₂O₇, resulting in the formation of the bamboo-leaf-like corrosion pits. As the SiC specimens etched in the HNO₃ solution at room temperature for 75 days, about 80 μm thickness corrosion layer forms. The weight loss and bending strength reduction of the etched SiC specimens are 2.6 mg/cm² and 52%, respectively. The corrosion of the SiC specimens is accelerated in the 70 °C HNO₃ solution with a rate about five times bigger than that in the same corrosion medium at room temperature.     

Improving Toughness of Heavy Steel Plate by Deformation Distribution Under Low Finish Cooling Temperature

The significant role of deformation distribution in toughness improvement of heavy steel plate under low finish cooling temperature was investigated. Deformation distribution was conducted by changing temperature-holding thickness in two-stage control rolling. The results show that the low finish cooling temperature always inhibits the ferrite transformation. However, when heavy deformation was applied at noncrystallization region, extensive ferrite was formed and ferrite was also effectively refined. Hence, homogeneous ferrite microstructure through the thickness with the ferrite volume fraction of 82.4% and grain size refined to 6.7 μm at quarter thickness of 40-mm heavy steel plate was obtained when the deformation at nonrecrystallization region reaches 70%. Thus, high toughness can be achieved, showing that the fully ductile fracture can be maintained at ?60 °C and the ductile-to-brittle transition temperature is lowered to ?91 °C. The improved toughness is ascribed to the high ferrite volume fraction, refinement of ferrite and hard phase colony and the increase in the percent of high-angle grain boundaries and average grain boundary misorientation.     

Experimental Investigation on Strengthening Effect of Cu<Subscript>2</Subscript>O Film in Micro Sheet Forming of Copper

Materials processed using micro-manufacturing technologies exhibit significantly different properties compared to those produced using conventional macro-manufacturing techniques. In this paper, the uniaxial tensile tests were performed on the thin sheet specimens of pure copper to investigate how the sheet thickness impacts the flow stress. The experimental results show a continuous decrease of flow stress as the sheet thickness reduces from 200 to 100 μm, but an increase of flow stress with further reduction in thickness. Firstly, by introducing the ratio of surface grains, the decrease trend of flow stress was explained on the basis of surface layer model. Secondly, the strengthening effect of Cu₂O film was clearly demonstrated by the x-ray diffraction and electrodeposition process. Finally, considering the effects of Cu₂O film and free surface layer, the mechanical properties of Cu₂O film was studied, which is helpful to explain the material behavior in micro sheet forming.     

电催化氧化甲醇反应低成本高活性的Pd核@Pt壳纳米粒子的光化学合成与表征研究(英文)

研究了PEG-丙酮体系中光化学合成Pd纳米粒子并在同一体系内在获得的Pd纳米粒子表面光化学还原Pt(IV)离子获得Pd核@Pt壳纳米粒子。通过改变Pd晶种对Pt(IV)的比例,能够有效调节复合粒子的Pt壳厚度。经HR-TEM和XPS分析,结果表明,获得的纳米粒子的平均粒径为5.3~7.1 nm,具有核-壳复合结构。电化学分析表明Pd:Pt摩尔比1:1、4:1的Pt核@Pt壳纳米粒子具有与Pt相似的催化活性和稳定性,且成本更低,可能被用作直接甲醇燃料电池阳极催化材料。     

轮胎硫化胶囊和胶囊注射法生产（三）

介绍了轮胎硫化胶囊的结构和特点.详细总结和分析了轮胎硫化胶囊注射法生产的特点、制作工艺、胶囊注射硫化机基本结构与工作原理.总结论述了各种结构的特点及主要性能参数.另外还分析了注射法生产硫化胶囊的主要缺陷和解决方法.