稀土湿法冶金工业中的化工问题

本文简略介绍了我国稀土湿法冶金工业中的一些化工问题，具体分析了解决问题的可能途径。提出了对革新现有的稀土生产流程应进行的基础和应用研究的几点看法。

ON THE ANALYSIS OF THE END-NOTCHED FLEXURE SPECIMEN FOR MEASURING MODE-II FRACTURE-TOUGHNESS OF COMPOSITE-MATERIALS

This paper deals with the correction of mode II strain energy release rate, G(II), of composite laminates measured with the end-notched flexure (ENF) specimen. A derivation is given of the expressions for compliance and strain energy release rate, in whic

离子色谱法测定人参中的微量氟含量

本文用离子色谱法,电导检测器,对不同部位人参含氟量分布进行了测定。样品称量范围5～15mg。仪器最小检测下限为0.05μg/ml。该方法与分光光度法对照,结果基本一致。

DIELS-ALDER REACTIONS CATALYZED BY LANTHANIDE CHLORIDES

Lanthanide chlorides have been found to catalyze the Diels-Alder synthesis of 2-butoxy-3, 4-dihydro-2H-pyran and several norbornene derivatives under mild conditions. In particular, the heavier lanthanide chlorides are very active catalysts for some (4 + 2) cycloaddition reactions. The catalyst activities and selectivities generally increase with increasing atomic number of the rare earth elements.