Uranium is an element of variable valency .

铀是 变价元素， 还原 体 （ 体系 ）在铀富集过程中起着 相当重要的 作用。

The ISS desulfurizing catalyst is a multi-component compound wet oxidative desulfurization catalyst composed of a compound coordination complex of metallic iron of variable valency as the main redox catalyst and mixed polyphenols as the auxiliary redox catalyst with the addition of other functional aids .

ISS脱硫催化剂是一种多元复合型湿式氧化脱硫催化剂，以 变价金属铁的复合配位络合物为主氧化-还原催化剂，配以混和多酚类物质为辅氧化-还原催化剂，再添加其它功能性助剂组成。

A Theoretical Model for Variable Valency Ion-Selective Electrode

变价 态离子电极的理论模型

Explanation for the Special Behaviour of the Variable Valency Ion Selective Electrode

变价 态电极的行为机制

The speckles and other abnormalities found on the surface of metallized electronic-vacuum ceramics containing 95 % alumina were investigated by way of micro-zone SEM analysis and microbeam scanning XRD from which it is concluded that the black speckles are formed by variable valency metal ions .

应用SEM微区分析和小束XRD扫描，对95%氧化铝电真空陶瓷金属化后的表面斑点等异常现象进行剖析。确认了表面黑点是由 变价金属离子形成的；