Identification of vivianite,an unusual blue pigment,in a sixteenth century painting and its implications

Vivianite, a blue pigment employed in the past practically only in Northern and Central Europe, but with very limited use, was identified in an early sixteenth century painting, stylistically with Flemish features, from a church in Portugal. The identification of this iron phosphate mineral was made by SEM‐EDS based on the atomic ratio between phosphorus and iron in layers of blue paint (area analysis) and in particles of these same layers (spot analysis). This painting, about which there is no document to prove its authorship, becomes the first case, known in detail, of a sixteenth century painting containing vivianite. Moreover, this find and the presence of a chalk ground, also identified, strongly support the hypothesis of being a Flemish painting.     

导线物证的扫描电镜及能谱鉴定方法

对导线物证同一性的鉴定，可先用X射线能谱仪快速确定物证为同一物的必要条件，再用扫描电镜对物证的特征条纹或金相组织进行最后判定。该方法简便，可靠。     

X射线透射成像技术原位追踪混凝土吸水过程

为了表征二维混凝土的传输过程,制备厚度为1 mm的混凝土薄片. 采用X射线透射成像（TXR）技术,联合扫描电镜、背散射和能谱分析技术（SEM/BSE/EDS）原位追踪水在2维混凝土薄片中的毛细自吸过程. 测试不同质量分数CsCl溶液对X射线透射图像的增强效果. 结果表明,CsCl能够提高吸水过程中混凝土薄片的TXR图像对比度,使得水在混凝土中的渗流路径更清晰、可辨. 水泥浆体在吸收CsCl后,扫描电子背散射图像的对比度显著增强. 不同位置铯原子的EDS能谱结果验证了TXR技术确定吸水前锋位置的准确性.     

超细矿粉对混凝土界面区硫酸盐腐蚀的影响

为了研究骨料与水泥石界面区(ITZ)的组成及结构对混凝土抗硫酸盐腐蚀性能的影响,利用紫外分光光度计绘制了硫酸钠溶液浸泡混凝土试样的SO2-4浸入浓度/深度曲线,并辅以扫描电镜(SEM)和电子探针能谱(EDS)等对ITZ进行观测;同时利用XRD定量分析研究了混凝土本体相和界面相的水化产物富集的差异.结果表明:Ca(OH)2、钙矾石(AFt)等晶体富集于硫酸钠溶液浸泡后试样的ITZ,引起AFt二次结晶型的硫酸盐腐蚀破坏.在适量石膏的激发下,掺入超细矿粉(GGBS)可阻止AFt转变成单硫型水化硫铝酸钙(AFm),减少AFt二次结晶的生成,明显提高抗硫酸盐侵蚀能力,试样的同深度硫酸根浓度最低,抗硫酸盐侵蚀性能最好.     

天然帽用草纤维的形态结构及EDS能谱分析

对蓆草、棕丝草、琅琊草、咸草、蒲草等5种帽用草纤维用扫描电镜观察其表面形态和截面结构,发现帽用纤维表面存在大量的气孔和沟槽,测量出气孔的长度20-73μm,宽度8-33μm。截面有较大的空隙,纤维空隙的大小依次是棕丝草、蒲草、琅琊草、蓆草、咸草。对其表面选取微区进行EDS能谱分析,结果表明5种帽用草纤维都含有C、O、Al,且C、O元素的含量都在96.99%以上,其他如Si、Na、Mg、Cl、P等属于微量元素,属纤维素纤维。     

Effects of microstructural heterogeneity on very high cycle fatigue properties of 7050-T7451 aluminum alloy friction stir butt welds

In this study, the very high cycle fatigue (VHCF) properties of 7050-T7451 aluminum alloy and its friction stir welding (FSW) butt welds have been investigated. The results show that the failure of FSW joints still occurs at 7.0 × 10⁸ cycles. The fatigue properties of the FSW joints are superior to those of the base material, especially in the super long life regime. Most fatigue cracks initiate at the thermo-mechanically affected zone and heat affected zone on the advancing side of the FSW joints, and the susceptibility of these zones to fatigue is attributed to the metallurgical heterogeneity.     

Effect of initial composition on phase selection in Ni–Si powder blends processed by mechanical alloying

The effect of initial powder blend composition on the synthesis and formation mechanism of nickel silicide phases was investigated by mechanical alloying in Ni-60 and Ni-66.7?at.% Si powder blends. It was noted that the equilibrium NiSi phase started to form in the early stages of milling and that the amount of the NiSi phase in the milled powder increased with increasing milling time. Even though, under equilibrium conditions, a mixture of both the NiSi and NiSi₂ phases was expected to be present in the Ni-60?at.% Si composition and the stoichiometric NiSi₂ phase in the Ni-66.7?at.% Si composition, the NiSi phase was present in both the compositions investigated. However, while only the NiSi phase was present homogeneously in the Ni-60?at.% Si powder blend, both the NiSi phase and a very small amount of unreacted Si were present in the powder blend of Ni-66.7?at.% Si composition. This unexpected phase constitution in the milled powders was attributed to a partial loss of Si during mechanical alloying of the powder blends, confirmed by energy dispersive X-ray spectrometer analyses, and explained on a thermodynamic basis.     

专家数据库EDS的设计与实现

在分析、比较数据库和知识库的各方面优缺点的基础上,介绍了专家数据库EDS的有关概念,并给出一个专家数据库系统的设计方案,最后详细阐述了系统的实现过程。     

MIG Brazing of Galvanized Thin Sheet Joints for Automotive Industry

MIG welding of zinc-coated thin plates in the automotive industry leads to major issues, mainly zinc evaporation followed by a decrease of corrosion resistance, as well as residual strains and stresses difficult to minimize. The use of a lower heat input technique for joining galvanized steels would bring significant benefit, if the final overall mechanical properties of the joints are adequate for the application. The use of MIG brazing (MIGB) with the recently commercialized alloyed copper-based filler metal is an alternative worth considering. The present paper addresses the MIGB processes, describing the influence of the different shielding gases and the process parameters on the mechanical, corrosion, and metallurgical properties of the joint, when lower heat input procedures are targeted. The paper describes the influence of the gases on the mechanical properties of the brazed joint, both in normal conditions after joining and after corrosion in a salt water environment. Microstructural features of the different zones are discussed. Results of corrosion and tensile tests are presented and interpreted.     

一种适用于配电自动化系统的新型以太网通信方式

鉴于通信系统是实现配电自动化系统的重要组成部分,采用一种新型的网络设备成功组建配网通信模式算是我们在这方面的一次大胆探索。目前比较先进的配电主干通信网多采用光纤加光纤收发器或光端机构成的光纤环网,在此采用一种由工业以太网设备服务器或交换机(EtherDeviceServer,简称EDS)代替光纤收发器或光端机的新型通信方案。从多层次对它们进行了比较,并对这种新型通信方式的特点、先进性及可推广性做了重点说明。嵌入该新型通信方式的配电自动化系统产品已投入现场运行。实践证明,其性能优越,技术先进,值得推广。