Mn元素含量对富铁8系铝合金铸轧板组织的影响

通过电子背散射衍射(EBSD)、扫描电镜(SEM)、X射线衍射(XRD)、光学显微镜(OM)等分析了Mn元素含量对富铁8系铝合金铸轧板组织的影响。结果表明:随着Mn元素含量的升高,铸轧晶粒从边部到中心的晶粒长短轴比减小,晶粒尺寸呈现出增大的变化趋势,且越接近中心越接近等轴晶;合金中心的第二相体积分数呈现出随着Mn元素含量的增加逐渐升高的变化趋势,且会促进β-Fe富铁三元相逐渐向α-Fe富铁四元相的转变;Mn元素含量会对合金的织构含量产生一定的影响,且会促进随机取向织构逐渐向FCC晶体结构中典型的β取向线织构的转变。

Photosynthetic capability and Fe, Mn, Cu, and Zn contents in two Moraceae species under different phosphorus levels

The strong adaptability of Broussonetia papyrifera （L.） Vent. to low phosphorus （P） conditions can be attributed to the large amount of root-exuded organic acids and the high efficiency of P extraction. However, microelement contents are influenced by low-P stress, and their effects on the photosynthetic capability of B. pa- pyrifera remain unknown. In this study, we investigated the effects of low-P treatment on net photosynthetic rate （PN）; chlorophyll a fluorescence （ChlF） characteristics; and Fe, Mn, Cu, and Zn contents of B. papyrifera and Morus alba L. seedlings. Results show that B. papyrifera exhibited better photosynthetic capability under moderate P defi- ciency （0.125, 0.063, and 0.031 mmol/L P treatments）, whereas the photosynthetic capability of M. alba decreased under moderate and severe P deficiency （0.016 and 0 mmol/L P treatments）. Under moderate P deficiency, the decrease in Cu and Zn contents in B. papyrifera was lower than that in M. alba. Under severe P deficiency, a consid- erable decrease of photosynthetic capability in B. pa- pyrifera and M. alba was associated with low Cu and Zn contents. The PN of the two Moraceae species exhibited a better correlation with Cu and Zn contents than with Fe or Mn content. P deficiency could not only decrease cyclic photophorylation and photosynthetic efficiency, but could also affect the stability of thylakoid membrane structureand electron transport efficiency by influencing the con- tents of Cu or Zn, thereby affecting photosynthesis.

牡荆叶茎中Zn Fe Cu Mn微量元素测定

目的：了解牡荆叶、茎中Zn、Fe、Cu、Mn4种微量元素的分布情况。方法：采用硝酸和高氯酸（体积比为4＋1）分解样品，火焰原子吸收光谱法测定牡荆叶、茎中微量元素Zn、Fe、Cu、Mn的含量。对各元素进行了加标回收试验，回收率在95．00％～103．70％之间，RSD〈4．9％。结果：相关微量元素在牡荆叶、茎中均含量丰富。结论：牡荆茎、叶中Zn、Fe含量差异较大，Cu、Mn含量差异相对较小。