Assessment of internal defects of hardfacing coatings in regeneration of machine parts

This paper presents the use of computed tomography for the evaluation of hardfacing. The method used in this research is hardfacing by tungsten inert gas using alloy wires of wear resistant layers. This paper discusses the latest materials used for hardfacing and their application. It characterizes the defects of obtained hardfacing and impact of the type of wire on the concentration of defects. It further, the basic mechanical properties of coatings were determined. The results are subjected to qualitative and quantitative analysis. The smallest average percentage of defects in relation to the overall surface is observed for the hardfacing EL-600 HB, which amounts to 1.5%. The highest average percentage of defects in relation to the overall surface is observed for the hardfacing EL-500 HB, which amounts to 7.2%. The chemical composition of hardfacing has been presented.

紫外光促进苦荞中黄酮类化合物积累的分子机制探究

目的研究紫外光对苦荞Fagopyrumtataricum幼苗中黄酮类化合物的影响及其分子机制。方法采用中波紫外光紫外线B(Ultraviolet Radiation B,UVB)处理苦荞幼苗,通过超高效液相色谱仪检测紫外光处理前后苦荞中芦丁等黄酮类化合物含量变化,同时采用实时荧光定量PCR(qRT-PCR)检测苦荞中黄酮类化合物合成途径中关键酶基因的表达量。结果紫外光处理后苦荞中芦丁、儿茶素和表儿茶素3种黄酮类化合物的含量均显著增加,其中芦丁含量是黑暗处理对照组的1.5倍。同时通过qRT-PCR检测发现苦荞中黄酮类化合物合成途径中苯丙氨酸解氨酶(phenylalanine ammonia lyase,PAL)、肉桂酸-4-羟化酶(cinnamate-4-hydroxylase,C4H)、黄烷酮-3-羟化酶(flavanone-3-hydroxylase,F3H)、二氢黄酮醇-4-还原酶(dihydroflavonol-4-reductase,DFR)等11个关键酶基因的表达量均有不同程度升高。结论UVB通过正调控多个黄酮合成关键酶基因的表达促进苦荞中黄酮类化合物的积累,为阐明UVB对苦荞中黄酮类化合物的调控机制奠定基础。