Effect of Heat Treatment on Microstructure and Mechanical Properties of Extruded PM Ti–6Al–4V Alloy With Deformation Flowlines

Metallurgical and Materials Transactions A - Two heat treatments, namely 955°C/2h/AC (AC = air cooling) and 955°C/4h/FC (FC = furnace cooling), were carried out on...     

浅析影响磁带录像机互换性的各种因素

磁带录像机 ,顾名思义 ,是记录或播放图像的设备。195 6年 ,美国安培公司成功地推出了第一台磁带录像机 ,使节目的后期制作 ,以及节目的交流变得方便和快捷。目前 ,随着广播电视事业的发展 ,电视台的规模和数量都有了很大增加 ,而且社会上也涌现出了很多的节目制作公司。虽然它们之间的节目交流有的可以通过卫星、微波、光缆等现代化手段 ,但在大多数情况下 ,还是以磁带作为媒介来进行的 ,因此 ,录像机间的互换性就变得非常重要。1互换性的概念一台合格的磁带录像机 ,它所记录的磁带 ,必须能在其它任何一台同一格式的录像机上很好地重放出标…     

催化裂化装置催化剂跑损量大的原因及解决措施

近几年,中国石油大连石化分公司Ⅱ套催化裂化装置一直存在催化剂跑损量大的问题,自然跑损量达2.0 kg/t,严重时超过2.5 kg/t,形成低料位或"零"料位操作.由此产生两个问题:一是再生线路推动力降低,斜管催化剂流化波动大,流化极易中断,事故状态下抗风险能力下降,操作苛刻度增大;二是装置运行后期催化剂消耗逐渐增大,不但使装置的运行成本增加,而且对烟气轮机等关键设备磨损加剧,装置无法正常运行.通过针对再生器的一系列操作试验,确定了再生器内部改造方案:再生器第二密相床主风分布管由原来的一根环形管改成一根三瓣形管,由倒L形快速分离器代替粗级旋风分离器,使用PLY型旋风分离器和重锤式翼阀.经过改造后,催化剂自然跑损量降低至1.0 kg/t、能耗降低10%、助燃剂消耗减少50%、反应再生系统操作状况得到改善.     

LOSA-1多产丙烯助剂的工业应用

近几年，随着化工市场的兴旺，丙烯的价格一路攀升，国内催化裂化装置在保证原油二次加工负荷的前提下，纷纷通过不同的技术改造、操作调整、改变催化剂等手段来多产液化气和丙烯。为此我公司二催化装置在不做工艺改造的前提下，应用了岳阳三生化工有限公司生产的LOSA-1增产丙烯助剂，取得了液化气产率增加4个百分点以上、丙烯产率增加1.7个百分点以上良好效果。     

配接MIC-80微机的液体闪烁测量系统中样品化学发光的检测及该系统程序中一些问题的考虑

一、样品化学发光的估算 与淬灭现象相反,样品化学发光在液闪测量中会导致假计数。为此,在每次建立新的样品制备方法之后都需估计该方法是否会导致化学发光,若有,还要估计它对测量结果影响的程度。已有多种检测化学发光的方法报道,但大多有各自的缺点:用不含放射性的对照样品的方法则比较费时间:用双重外标准源道比法需专门绘制一条标准曲线且在淬灭严重时检测有困难;用延迟符合的技术则需要增加电子学线路。在我们的配接了MIC-80微机的YSJ型液闪仪上,当进行化学发光检测时,仪器会自动给出样品化学发光的估算值nc。若nc=0,则可肯定样品无化学发光或者说化学发光对测量结果无影响;若nc≠0,则提示我们,该样品可能有化学发光存     

水热法合成云母氧化铁结晶条件

云母氧化铁为鳞片状细微晶体,有金属光泽,其主要化学成分为α-Fe2O3．由于是片状结构,它具有优良的耐介质性、耐大气老化和封闭性能,作为底漆和面漆应用十分广泛．近年来,随着磁性材料、涂料工业等的发展,对云母氧化铁的纯度、粒度及形貌提出了更高的要求．目前云母氧化铁大多     

Dry-Sliding Tribological Properties of Bronze–Graphite Composites

Bronze-uncoated and nickel-coated graphite composites were fabricated by powder metallurgy route. The tribological behaviors of composites sliding against AISI52100 steel ball under dry sliding condition were studied using a ball-on-disk tribometer. The nickel-coated graphite composites showed much better tribological properties in comparison with bronze and uncoated graphite composite. The friction coefficient of nickel-coated graphite composites decreased with increasing nickel-coated graphite content. However, the specific wear rate increased with the increase in nickel-coated graphite. The composite containing 15?wt% nickel-coated graphite showed the best self-lubricating properties because the compacted and stable mechanical mixed layer was formed on the worn surfaces. The wear mechanism of bronze 663 is adhesive wear and abrasive wear. The uncoated nickel-coated graphite composite shows the adhesive wear and delamination characteristics. However, the wear mechanism of nickel-coated composites is mildly abrasive wear.     

Rule-based detection of design patterns in program code

The process of understanding and reusing software is often time-consuming, especially in legacy code and open-source libraries. While some core code of open-source libraries may be well-documented, it is frequently the case that open-source libraries lack informative API documentation and reliable design information. As a result, the source code itself is often the sole reliable source of information for program understanding activities. In this article, we propose a reverse-engineering approach that can provide assistance during the process of understanding software through the automatic recovery of hidden design patterns in software libraries. Specifically, we use ontology formalism to represent the conceptual knowledge of the source code and semantic rules to capture the structures and behaviors of the design patterns in the libraries. Several software libraries were examined with this approach and the evaluation results show that effective and flexible detection of design patterns can be achieved without using hard-coded heuristics.     

采煤机滑靴激光熔覆铁镍基涂层的抗磨性能*

为提高采煤机滑靴在无油工况下的耐磨性,采用激光熔覆技术在45钢为基体上分别制备FeNiMo和FeNiMoSi涂层,并对其物相组成及硬度等进行分析。结果发现：制备的涂层结构致密,与基底保持了良好的冶金结合;FeNiMoSi涂层的平均硬度为438HV,分别约为基体（153HV）的2.8倍以及FeNiMo涂层（385HV）的1.1倍。通过往复式摩擦磨损试验机研究涂层的干摩擦磨损性能,并探讨其磨损机制。结果表明：随着载荷和滑动速度的增大,涂层的摩擦因数均呈现出减小的趋势;随着载荷的增大,涂层的磨损率逐渐升高;随着滑动速度的增大,FeNiMo涂层的磨损率出现先下降后上升的趋势,而FeNiMoSi涂层的磨损率则逐渐下降;涂层的磨损机制主要为磨粒磨损、塑性变形以及轻微的氧化磨损。总体来说,FeNiMoSi涂层相比FeNiMo涂层表现出更好的耐磨性能,这是因为涂层中Si元素的添加,不仅起到细晶强化作用,而且促进了FeSi金属间化合物相的生成。