纸浆漂白过程流中非过程铁元素的表征

以新制铁和陈化铁模拟纸浆漂白过程流中的非过程铁元素,研究了非过程铁元素存在颗粒的粒径大小和分布、表面形态和物象组成.研究发现,新制铁胶体颗粒以纳米级存在(210～250 nm),并随体系pH值增加而增加,其密度和体积分布呈双峰分布.70 ℃水浴加热1 h后,新制铁胶体颗粒粒径明显增加,pH 13时达到1 620 nm.陈化铁颗粒粒径较大,高达10 μm.IR、XRD、SEM-EDS分析表明,以新制铁形式的非过程铁胶体颗粒没有结晶成分存在,其宏观分子式为Fe29.1O17.2(OH)52.9;以陈化铁形式存在的非过程铁胶体颗粒主要以Fe2O3晶体存在,其宏观分子式为Fe34.7O38.8(OH)26.5.     

Effect of High Pressure Pretreatments on Structural and Dehydration Characteristics of Aloe Vera (Aloe barbadensis Miller) Cubes

The effect of high-pressure (HP) pretreatments (300–500 MPa for 5–15 min) on dehydration characteristics of aloe vera cubes (AVC), dried at 50–70°C and air velocity of 1–2 m/s, was studied. Pretreatments resulted in higher drying rates, leading to a reduction in drying time compared to untreated ones. The drying rate and drying time were most significantly affected (p < 0.05) by the drying temperature, followed by air velocity, pressure level, and dwell time. HPP enhanced the firmness of AVC with a maximum of up to 21% for the sample treated at 500 MPa for 15 min. Microstructural analysis using scanning electron microscopy (SEM) indicated non-uniform structures in the pretreated and dried AVC samples. Semi-quantitative elemental detection (EDS) confirmed the presence of a considerable amount (14%) of calcium in aloe vera.     

高强度工程机械用钢铸坯夹杂物分析

为了解某厂高强度工程机械用钢Q550MD铸坯夹杂物来源,优化生产工艺,提高铸坯质量,采用大样电解和夹杂物自动扫描分析方法,对铸坯中夹杂物数量、尺寸、形貌及成分进行研究。结果表明,电解试样中大型夹杂物尺寸集中在80~140 μm,形状大多为球形,主要成分为铝酸钙。铸坯中大型夹杂物在形成最终复合夹杂物前均来自于钢包,且可能发生结晶器卷渣。检测的铸坯宽度方向1/4位置发现夹杂物聚集现象,夹杂物数量明显高于边部和1/2位置,这与结晶器流场不合理有关。     

机动车三元催化剂结构性能的研究

当前治理汽车尾气污染的最好方法是采用含有贵金属的三元催化剂同时对NOx、HC、CO进行处理.催化转化器的结构性能直接影响催化效率的高低,准确测定及鉴定催化剂中主要部件的结构性能指标就具有重要意义.该文利用X-射线衍射光谱仪(XRD)、扫描电子显微镜能谱分析技术(SEM-EDS)以及等温液氮吸附-脱附技术对6种使用过的和未使用过的机动车尾气三元催化剂的结构性能进行分析研究.结果表明:可以通过X-射线衍射光谱仪区分各催化剂载体的材质,文中样品经鉴定都为堇青石陶瓷蜂窝载体,不同催化剂的比表面积和孔容存在差异;通过扫描电子显微镜可以观察到催化剂载体表面涂层的微观结构,及一些催化剂载体表面涂层出现的裂纹;通过能谱分析各载体主要元素的大致含量.     

某含银铅锌硫化矿石工艺矿物学研究

采用X射线衍射(XRD)和扫描电镜-能谱(SEM-EDS)等方法研究某地含银铅锌矿的工艺矿物学性质,查清矿石的化学组成,并对该区矿石中银矿物的组成、嵌布特征和赋存状态进行分析,通过单浮选试验确定最佳磨矿细度。研究结果表明,方铅矿和闪锌矿为银的主要载体矿物,且银矿物以较细的粒度嵌布于方铅矿和闪锌矿中,磨矿细度以-74μm占75%为最佳,该研究可为含银铅锌矿的综合回收提供指导。     

劣质蜡油加氢处理催化剂上金属杂质沉积规律研究

在缓和加氢条件下,采用新研制的FCC原料预处理催化剂处理含渣劣质蜡油,研究反应规律和杂质沉积规律。结果表明,研制的催化剂孔容和平均孔径较大,金属杂质在整个床层均匀沉积,在每个颗粒中由边缘到中心也均匀分布,这种沉积特点提高了催化剂活性稳定性。在2 500 h连续实验运转过程中,脱硫率无明显下降。     

蒙特卡罗模拟在单颗粒扫描电镜-能谱定量分析中的应用研究

使用扫描电镜-能谱分析技术在10kV/1nA条件下分别对微束分析国家标准样品、K411玻璃微球和自制的颗粒标准样品进行了测试,并用CASINO程序对其进行了元素定量计算,以检验蒙特卡罗模拟在单颗粒分析中的适用性。研究结果表明:(1)无论是块状还是颗粒标准样品,CASINO程序给出的定量计算结果总体上都明显优于能谱仪自带的XPP程序;(2)相比归一化法,CASINO程序能显著地校正颗粒效应;(3)对于Cu、Zn等KαX射线荧光产额较低的元素,在其含量较低时最好使用Lα线进行定量计算;(4)对于Cr2O3等存在严重谱线重叠的样品,进行相应的重叠校正也可得到较为准确的定量计算结果。     

场发射扫描电镜-能谱仪在胶料喷霜研究中的应用

本文通过SEM-EDS对胶料中不溶性硫磺及NS喷出进行分析。氧化锌和NS会促进混炼胶中不溶性硫磺的转化并喷出,为无定型结构;硫化胶中过量的NS会随着时间的延长而喷出,为长方体规则结构。SEM-EDS联用技术可以应用到胶料喷霜物的鉴别中。     

Roman situlae from Conimbriga (Portugal): Compositional and microstructural characterization of anthropomorphic handle attachments

ABSTRACT

A collection of 33 anthropomorphic handle attachments of Roman situlae recovered from the archeological site of Conimbriga (Central Portugal, 2nd century BC–5th century AD) was studied by micro-Energy Dispersive X-Ray Fluorescence Spectrometry (micro-EDXRF), Scanning Electron Microscopy - Energy Dispersive Spectroscopy (SEM-EDS) and metallographic techniques. Regarding the characterization of Roman artifacts of regional production, the relation among typology, composition and microstructure was evaluated in order to infer the Roman influence on the copper metallurgy in Western Iberia. The collection was found to be heterogeneous, mainly constituted by leaded copper and leaded bronzes, with a wide range of lead contents. The artifacts were all produced by mold casting, and most of them show some post-casting processing. Important casting faults and broken artifacts were associated with higher lead contents, and were mainly leaded copper. The leaded bronzes were more carefully produced. The overall results suggest a local metallurgical tradition, with the usage of copper and copper alloy scraps, with high additions of lead. The aim was to produce colored (and cheaper) artifacts, without any major concerns about the finishing details.     

Experimental determination of 800 °C isothermal section in Al-Zn-Zr ternary system

The 800 °C isothermal section in the Al-Zn-Zr system was investigated using the equilibrated alloy method and the solid/liquid diffusion couple approach by means of scanning electron microscopy equipped with energy dispersive spectroscopy, X-ray powder diffraction and electron probe microanalysis. Thirteen three-phase regions are experimentally confirmed in the ternary system. A ternary compound Zn₅₀Al₂₅Zr₂₅ named as T phase exists stably in the 800 °C isothermal section. Its composition range varies widely (16.84-55.1 at.% Zn, 18.02-56.3 at.% Al and 26.0-28.53 at.% Zr), and it can be in equilibrium with all the binary compounds. The maximum solubilities of Zn in Zr₃Al, Zr₂Al, Zr₃Al₂, Zr₄Al₃, ZrAl, Zr₂Al₃, ZrAl₂ and ZrAl₃ are 7.5, 0.84, 0.33, 0.89, 0.91, 1.12, 0.64 and 3.8 at.%, respectively. The maximum solubilities of Al in Zn₃Zr, Zn₂Zr and ZnZr are 1.6, 1.3 and 13.6 at.%, respectively.