摘要
为获得接近太阳光的自然发光效果,制备了Eu2+掺杂的硅基氮化物系列荧光粉,并对其发光特性及原理进行研究.采用碳热还原氮化法制备了Eu2+掺杂SrSiO3-Sr2Si5N8-SrSi2O2N2红色荧光粉.利用X射线衍射仪(XRD)、荧光分光光度计、MS-CASTEP对产物物相、发光光谱、电子结构进行了测试分析.结果发现:通过调节煅烧工艺参数,可同时获得2种主要物相或者单一物相的荧光粉;所制备的荧光粉,能够在350~400 nm范围内被UVLED很好地激发,根据主晶相的不同,产物的发射光谱可以在400 nm~700 nm波段内调控.采用第一性原理分析了发射峰位于650 nm附近橙红色主晶相Sr2Si5N8∶Eu2+的电子结构和光物理性能,发现该物相为直接带隙半导体材料,Eu2+的4f轨道对费米面电子峰起主要作用.Eu2+掺杂SrSiO3-Sr2Si5N8-SrSi2O2N2是优良的、颜色可调控的红色荧光粉材料.
To study the influence of surface integrity on the vibration fatigue properties of superalloy blade, the dynamic analysis of certain super?alloy blade during the experiment of vibration fatigue was performed by using the finite element method. The stress distribution during the vibration was obtained. The influences of residual stress and roughness on the vibration fatigue properties of blade were investigated. The results show that the stress amplitude in the vibration process increases at first and then decreases. There is a beat vibration phenomenon that the stress amplitude changes periodically during the blade resonance vibration. The limited fatigue strength of blade decreases with increasing residual stress and roughness. The relationship between the limited fatigue strength and residual stress is σfat=510.9-0.31 -70.93σrest, and the relationship between the limited fatigue strength and roughness is σfat=9.67R2roughness-70.93 Rroughness+713.23.
出处
《材料科学与工艺》
EI
CAS
CSCD
北大核心
2015年第5期1-5,共5页
Materials Science and Technology
基金
广西自然科学基金(2011GXNSFA018019)
广西教育厅资助项目(201012MS095)
有色金属及材料加工新技术教育部重点实验室开放基金(12KF-11)
关键词
荧光粉
光致发光
荧光光谱
电子结构
vibration fatigue
residual stress
roughness
limited fatigue strength
stress response