GARDES工艺技术在汽油加氢脱硫装置生产国Ⅴ排放标准汽油组分中的应用

介绍了中国石油大庆石化公司（简称大庆石化）炼油厂汽油加氢脱硫装置应用GARDES工艺技术生产满足国Ⅴ排放标准汽油组分的工业实践。通过GARDES工艺技术,汽油加氢脱硫装置的混合汽油产品硫质量分数能够降低至5 μg/g、硫醇硫质量分数能够降至4 μg/g、烯烃含量能够降至30.1%、RON损失为1.3个单位,满足了汽油池调合国Ⅴ标准汽油的要求,解决了大庆石化,汽油质量升级的问题。     

超宽范围输入的开关电源电路设计

本文介绍了一种基于TOP242N集成芯片的超宽范围输入的开关电源设计方法,其输入电压可在80～400V的范围内正常工作,对单端反激式开关电源的电路及其外围电路的设计也进行了相关分析说明,其设计方法也适用于用其它的各类芯片的电路。     

军事或航空航天用新一代270V直流接触器

介绍了270V直流电源的由来及其在航空航天上的应用,分析了270V直流接触器密封陶瓷切换室和环氧密封技术的两种传统解决方案。并讨论了270V直流接触器的新技术高性能密封陶瓷（EPIC）技术。结果表明,采用EPIC技术的新型270V直流接触器成功地解决了电弧、干扰、重量、成本等难题,目前已通过了严格的鉴定试验。     

Effect of V on Hot Deformation Characteristics of TWIP Steels

Twinning induced plasticity (TWIP) steels, which rely on high Mn contents to promote twinning as the deformation mechanism, exhibit high ultimate strengths together with outstanding combinations of ultimate strength and ductility. In terms of mechanical properties, one of the most important microstructural features is grain size. The knowledge of the kinetics of recrystallization mechanisms, i.e., dynamic recrystallization (DRX) and static recrystallization (SRX), can be used in order to control the grain size of the final product by a proper rolling schedule design. The focus of this work is the characterization of the DRX kinetics of two TWIP steels. The basic composition of the steels is Fe–21Mn–0.4C–1.5Al–1.5Si, and one of them is further alloyed with 0.12% V. With this objective, compression tests were carried out at 900, 1000, and 1100°C and strain rates ranging from 1 × 10^?1 s^?1 to 1 × 10^?4 s^?1. Furthermore, metallographic observation by optical microscopy (OM) was done to assess the evolution of grain size for the different deformation conditions. According to the results, the existence of V in the composition does not affect the hot flow behavior of the steel, although recrystallization fraction and recrystallized grain size decrease for the V‐containing steel.     

30Cr1Mo1V转子钢应力强度因子有限元分析

通过采用20节点solid186退化奇异单元,利用ANSYS软件,对三维断裂参量进行计算和分析,结果表明位移法和J积分法确定应力强度因子是可行的;对一定尺寸的紧凑拉伸试样三维裂纹进行分析,得出30Cr1Mo1V转子钢裂纹尖端KI随裂纹长度和载荷水平改变时的变化规律,为研究汽轮机转子裂纹扩展规律提供了合理、有效的方法.     

基于CPDA V1.1的电力技术经济学实验教学内容研究

电力技术经济学作为技术经济学的一个分支,具有理论性和实践应用性强、理论知识创新速度快、多学科交叉等特点,这些特点的存在对该课程的教学方法和手段提出了更高的要求.本文从笔者教学实践出发,结合相关数据分析软件探讨电力技术经济学实验教学改革的内容.     

PowerFlex700变频器在升降机上的调速技巧

针对车间生产节拍提升的需求,对在用的罗克韦尔PowerFlex700系列变频嚣在升降机调速中所遇到的问题和调试步骤、方法技巧以及一些关键参数设置等,作了系统的介绍,希望能对同行起到一定的参考借鉴作用.     

Optimization of fluid bed formulations of metoprolol granules and tablets using an experimental design

Background: The granulation process of a metoprolol tartrate (very difficult to process active pharmaceutical ingredient) formulation in laboratory scale fluid bed equipment was studied. Aim: To study the influence of two formulation factors and three process parameters on the characteristics of the granules and subsequently of the tablets, in the case of fluid bed granulating of a powder mix containing metoprolol tartrate. Method: In order to study the influence of formulation factors (binder solution concentration and the silicon dioxide ratio) and process factors (atomizing pressure, the length of the final drying phase, and the inlet air temperature) on the technological and pharmaceutical properties of granules and tablets, a fractional factorial experimental design resolution V+ with five factors and two levels was used. Results: A high atomizing pressure allows us to obtain fine granules with large poly-dispersion index and granules with high tapped and untapped density, tablets with short disintegration time, short mean dissolution time, and a high percentage metoprolol tartrate release in the first 15 minutes. A lower concentration of binder solution allows us to obtain granules with very good flow properties, tablets which have no tendency to stick on the set punch of tabletting machine and no capping. The final drying time of granules has an influence only on the granule's relative humidity and tapped and untapped density, without any influence on the granules flow properties. Conclusions: The practical experimental results from the formulation processed in optimal working conditions were close to the predicted ones by Modde 6.0 software.     

Internal fatigue crack initiation in drawn Ti–6Al–4V wires

Fatigue cracks in titanium alloys are often found to initiate at faceted alpha grains. In the very high cycle fatigue regime, crack initiation tends to shift from the surface towards the interior of the material, and more initiation facets can be found on the fracture surface. In this study, fatigue tests were performed on drawn and heat-treated Ti–6Al–4V wires. Only a few samples fractured due to interior initiation. The facets at the initiation sites of these samples were not flat, but had markings on the nano-scale, and were highly inclined. A possible explanation for these aspects is the crystallographic texture of the wire, and a reflection is made on the suggested mechanisms of facet formation.

This paper is part of a Themed Issue on Euromech 570: Interface-dominated materials.     

Solidification and microstructure of ZA27/SiCp composite fabricated by mechanical–electromagnetic combination stirring process

Abstract

The solidification behaviours and microstructural characteristics of both ZA27/SiC_p composites and monolithic ZA27 alloy were studied by using differential scanning calorimetry, scanning electron microscopy, transmission electron microscopy, electron probe microanalysis, and X-ray diffraction. It was found that there were differences in the transformation temperature and volume fraction of the phases, although the solidification process was almost identical for the composite and the monolithic alloy. The incorporation of SiC particles in the ZA27 alloy led to slight refinement of primary grains and reduced volume fraction of eutectic-like phase. The SiC particles obstructed Zn diffusion in the residual melt during the formation of proeutectic β phase, but promoted Zn diffusion from (Al) to η (Zn) phase during eutectoid transformation. During solidification, Cu was mainly segregated in the final solidification regions; Mg was present not only in the matrix but also on SiC particles; and oxide inclusions were mainly distributed around SiC particles. The matrix microstructure for both materials mainly consisted of primary cores of Al rich +η eutectoid; β′ phase resulting from the eutectoid transformation of the proeutectic β phase; and Zn rich +η eutectoid resulting from the eutectoid transformation of the eutectic-like phase. The SiC particles were mainly distributed around the primary grains. Several new phases based on the Al–Zn–Mg–Cu system and interfacial reaction products, including Al₂₁Fe₃Si, Cu₅Zn₈, Mg₆Cu₃Al₇, MgAl₂O₄, and amorphous oxide inclusions, were identified in the final solidification regions. The nucleation of both primary phase and eutectic-like +η phase at the surface of SiC particles and their crystallographic orientation relationships were investigated theoretically and experimentally. No distinct crystallographic orientation relationship between the matrix and SiC has been identified, although the mismatch between (0001)_SiC and (111)_ was calculated to be as small as 7·6%.