撞击载荷作用下单层球面网壳动力响应模型实验研究

通过单层KIEWITT8型网壳模型在落锤撞击作用下的实验,研究单层网壳在撞击作用下的动力稳定性。利用动态应变仪和力传感器,获取了落锤撞击网壳时撞击力时程曲线、杆件轴力时程曲线和稳定临界力。利用高速摄影机拍摄了撞击历程、撞击失稳模态及破坏形态。结果表明:撞击作用为三角脉冲荷载形式,其最大幅值和脉宽与撞击冲量和网壳所处变形阶段的刚度性能相关;撞击荷载持续作用的时间为3.00~22.36 ms;撞击接触时间的突然增大对应着网壳的失稳;杆件开始响应的时刻比撞击力开始作用的时刻滞后0.2~0.4 ms;对失稳前的撞击,落锤回弹速度较大;对失稳时的撞击,落锤回弹速度很小;模型具有较大的后屈曲抗撞击能力,在顶点垂直撞击下没有发生连续断裂。     

A PRELIMINARY STUDY ON CLAY MINERALS AND REE AND Li IN CLAY ORES (ROCKS)IN HENAN PROVINCE

A detailed study on the clay minerals from the working area was carried out through multiple methods,including X-ray diffraction, infrared absorption, DTA and TG, TEM and SEM, Mossbauer spectrometry,electron paramagnetic resonance and wet chemical analysis. Cookeite was discovered in the area for thefirst time. The determination of REE, Li, Nb, Ta and Sc in various ores and rocks as well as in variousclay minerals and their associations, and the cation exchange experiments (soaking experiments) carried outin various electrolyte solutions and designed for judging whether Li is in adsorption state indicate (i)clay minerals contain highest REE, and (ii) Li exists mainly in its own mineral-cookeite.     

河南某粘土矿(岩)中粘土矿物及其稀土、锂等元素的初步研究

本文应用X射线衍射、X射线粉晶、红外吸收光谱、热分析(差热及失重分析)、透射及扫描电子显微镜、穆斯堡尔谱、电子顺磁共振和化学分析等多种方法,对本区粘土矿物进行了较为详尽的研究,锂绿泥石在本区属首次发现。各类矿(岩)石及粘土矿物(或其组合)中稀土、锂、铌、钽和钪的测定,以及为判别锂是否呈离子吸附状态所做的多种介质不同条件下的阳离子交换实验表明:(1)稀土总含量在粘土矿物中最高;(2)锂主要以锂的独立矿物——锂绿泥石形式存在,等等。