介绍了3种X射线空气质量衰减系数的测量方法:移动距离法、抽真空法、EGSnrc蒙特卡罗模拟计算法。给出了抽真空法中真空管内空气质量厚度改变量的计算公式,并模拟分析了真空管Be窗对实验的影响。移动距离法与抽真空法得到的结果较接近,验证了抽真空法实验的合理性。当X射线能量为6 ke V、20 ke V时,EGSnrc蒙特卡罗模拟计算结果与NIST标准数据库数值偏差分别为0. 01%、0. 26%。
Iron L-edge and sulfur K-edge X-ray absorption near edge structure（XANES） spectroscopy analysis of pyrite leached by extreme thermophilic Archaea strain Acidianus manzaensis（A.manzaensis） was carried out.Leaching experiments show that the oxidation of pyrite can be accelerated by A.manzaensis.Leaching results show that with the increase of leaching time,pH value in the leaching solution gradually decreases,redox potential increases rapidly from day 0 to day 3,and then increases slowly.The SEM results show that the pyrite surfaces are corroded gradually by A.manzaensis,and the XRD results show that the leaching residues contain new compositions of jarosite and elemental sulfur（S0）.The iron L-edge XANES spectroscopy analysis of pyrite during biooxidation indicates that pyrite is gradually converted to Fe（III）-containing species.The sulfur K-edge XANES spectroscopy analysis indicates that elemental sulfur is produced during bioleaching and maintains mass fractions of 3.2%-5.9%.Sodium thiosulfate was also detected from day 2 to day 4,indicating the existence of thiosulfate during biooxidation of pyrite.
