Fatigue crack growth in some PM low alloy steels consolidated by rotary forging and sintering

Abstract

Fatigue crack propagation rates under plane strain conditions have been investigated for three PM low alloy steels consolidated to high densities by rotary compaction followed by sintering and heat treatment. It is shown that the densities and properties are intermediate between those of pressed and sintered materials and of powder forged materials. Threshold stress intensities compare satisfactorily with those for wrought counterparts, but resistances to crack growth are inferior to those of wrought steels. Possible reasons for the properties of the rotary compacted materials are considered in the light of their microstructures and the behaviour of other PM materials.     

电能计量装置综合误差纠正功能在ION高端关口电能表中的实现

介绍了利用ION高端关口电能表的高精度、可编程、多通信口等功能．根据电能计量装置现场实际负载下的误差值,在表内实现计量装置综合误差实时计算和自动误差纠正,以及误差纠正前后电量的记录。     

SURFACE MODIFICATION OF TITANIUM FILMS WITH SODIUM ION IMPLANTATION： SURFACE PROPERTIES AND PROTEIN ADSORPTION

Sodium implanted titanium films with different ion doses were characterized to correlate their ion implantation parameters. Native titanium films and ion implanted titanium films were characterized with combined techniques of X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and light microscopy (LM). The surface presented increased sodium concentration on treated titanium films with ion dose increasing, except for the group with the highest ion dose of 4× 1017 ions/cm2. XPS depth profiling displayed that sodium entered titanium film around 25-50 nm depth depending on its implantation ion dose. AFM characterization showed that sodium ion implantation treatment changed the surface morphology from a relatively smooth titanium film to rough surfaces corresponding to different implantation doses.After sodium implantation, implanted titanium films presented big particles with island structure morphology. The surface morphology and particle growth displayed the corresponding trend.Fibrinogen adsorption on these titanium films was performed to correlate with the surface properties of treated titanium films. The results show that protein adsorption on ion-implanted samples with dose of 2 × 1017 and 4 × 1017 are statistically higher (p ＜ 0. 01) than samples treated with dose of 5×1016 and 1 ×1017, as well as the control samples.     

智能光网络技术及发展

本文在分析网络业务对光网络发展的推动以及智能光网络的光起之后，着理描述了智能光网络的技术要点，发展现状和趋势。     

Influence of Yttrium on the Oxidation of Pure Iron at 973 K; Comparison Between Ion Implantation and Sol-Gel Coatings

The influence of yttrium introduced by ionimplantation or by sol-gel coatings on the oxidation ofpure iron has been studied at 973 K underp(O₂) = 0.04 Pa. The oxide scales wereexamined using a wide range of analytical techniques. The addition ofyttrium by ion implantation or by sol-gel coatingssignificantly improved the oxidation resistance of pureiron. This effect depends upon the introduction mode of yttrium on the surface.     

自动交换光网络控制平面管理方案的分析和设计

自动交换光网络(ASON)作为智能光网络的典型代表,集中体现了下一代光网络向着智能化、大容量发展的方向。ASON网络中由于控制平面的引入,在为其带来了快速连接建立、自动资源发现等诸多特色功能的同时,也对这种新型网络的管理提出了新的挑战。如何通过对核心控制层面的管理保证网络的正常运行成为人们目前迫切希望得到解决的问题之一。我们首先讨论了控制平面的管理需求,并相应提出了针对控制平面的管理功能。最后,在此基础上,我们建立了具有层次清晰、功能明确等特点的控制平面网络和网元管理信息模型,从而形成了一种新的针对ASON控制平面的管理方案。     

N+ ion implantation-induced cell attachment to CNx coating prepared by ion beam assisted deposition

Ion beam-assisted deposition (IBAD) was used to synthesize carbon nitride (CN _x ) coatings on Ti-6Al-4V alloy at room temperature at 100-eV NHn⁺ beam bombarding energy. Nitrogen ion implantation was also conducted on the prepared coatings. The effects of ion fluence on the chemical bonding structure of the coatings were characterized by XPS, and Raman and FTIR spectroscopic methods. The results showed that N⁺ ion implantation increased the N concentration of the prepared CN _x coatings. The cell attachment tests gave promising results that N⁺ ion-implanted CN _x coatings exhibited low macrophage attachment. The adhered fibroblasts showed normal cellular growth and morphology. Under a fluence of 5 × 10¹⁷ ion/cm², the CN _x coating exhibits more N concentration and sp³ bonds which may be responsible for the changes in the cell attachment.     

基于ION Java的三维网络可视化初探

IDL是专门为海量的、多元的科学数据集的可视化和分析设计的第4代科学计算语言,Java2是基于网络应用开发的面向对象的新一代计算机编程语言,能够比较好地适应INTERNET编程.ION Java是将IDL与Java技术结合的一种应用,利用Java Applet技术,在网络环境下,实现IDL先进的图形可视化显示及分析功能.介绍了IDL的对象图形系统,并对ION Java体系结构进行说明,利用ION Java实现"三峡永久船闸"三维模型的网络可视化系统,利用IDL对象图形系统快速建立三维模型场景,利用ION Java提供的Java类实现了网络三维模型显示、查询及分析的功能.     

The Influence of Yttrium Implantation on the Oxidation of Impure Iron Containing C and Mn at 700°C

A study of impurity-yttrium interactions hasbeen performed during iron oxidation [p(O₂)= 0.04 Pa, T = 700°C]. Yttrium-implanted specimensalways exhibit better oxidation behavior compared withblank specimens. On pure iron or the Fe 0.054 wt.%C alloy thebeneficial effect is attributed toFe₂YO₄ formation. With themanganese-containing alloys (Fe 0.2 wt.%Mn), theprotective effect of yttrium is attributed to YMnO₃ formation. The best oxidationbehavior is obtained with implanted Fe0.18 wt.%Mn-0.041wt.%C alloys due to the formation of an YMnO₃oxide subscale at the scale-alloy interface. Yttriumimplantation also hinders carbon segregation at theoxide-alloy interface. This effect ensures better scaleadherence. With the most-impure alloy, yttriumimplantation also changes the growth process fromexternal cation diffusion to predominant inward-oxygendiffusion.     

Adhesional bonding of fine gold wires to metal substrates

The transition from the adhesional elastic contact to the elasto-plastic contact is discussed, using Au wires as cylindrical bodies. The simple compensation for elasto-plastic contact was numerically carried out to obtain smooth transition profiles from elastic to elasto-plastic contact, depending on the applied force f. Au wires with a diameter of 100 μm were contacted to Au plates and Si substrates after they were irradiated with Ar⁺ ions. It was found that the experimental contact width 2a was nearly equal to the theoretical adhesional elastic contact width 2aj when f was small enough (f < 500 N/m) but the contact width 2a gradually became greater than 2aj as f increased (f > 500 N/m), and became nearly equal to the elasto-plastic contact width a _ep . On the other hand, the actual fracture strength was much less than the theoretical fracture (pull) strength of the adhesional contact and it was also found that the experimental bond strength increased with increasing the holding time after bonding (contacting).