Photochromism in CaS : Sm

The photochromism in CaS:Sm (from white to pink) was observed for the first time by exposing it to ultraviolet light. The experiments results show that the absorption intensity of Sm2+ in the range of 500 similar to 600nm was strongly increased after irradiation. This reveals that there is the valence changing of Sm. If the sample was excited by visible light again, the pink color turned to white, indicating that CaS:Sm has potential application in the field of storage material.

CaS:Cu~+的热释发光性质

近年来对一些稀土和重金属离子在碱土金属硫化物的热释发光有过研究,,如CaS: Ce~(3+)和CaS:Bi~(3+)体系。N.Singh et al.(3)研究了CaS:Cu,Al以及CaS:Cu,Cl在UV辐照下热释发光峰值温度分别为80℃和75℃。我们用二甲亚砜硝酸钙为原料合成的CaS :Cu~+磷光体,在UV(366nm)辐照下,热释发光峰值温度大于100℃,峰值温度随铜离子浓度变化。

CaS:Cu~+磷光体的合成及发光性质

本文首先用X光电子能谱分析铜在硫化钙基质中是以一价形式存在的.在掺铜的硫化钙的激发光谱中,有三个吸收峰,峰位分别为268nm、307nm和400nm;在CaS:Cu~+的发射光谱中,产生四个发射峰,峰位分别为430nm、465nm、490nm和610nm.这四个发射峰分别由不同铜离子格位产生的.在Cas:Cu~+的热释发光曲线中,显示单一热释发光峰,峰值温度为120℃,该热释发光峰有可能用作紫外剂量材料.

CaS:Ce~(3+)磷光体的合成及发光性质

本文研究了不同合成条件对CaS:Ce~(3+)磷光体发光性质的影响。CaS:Ce~(3+)的发光强度随Ce~(3+)离子的浓度发生变化,最佳浓度为1.001×10~(-3)mol。对应于新的单一热释发光峰(426K)的陷阱参数为,陷阱深度E=1.01eV,逃逸频率因素S=1.2×10~(11)s~(-1),磷光体的热释发光满足二级动力学过程。

Observation and modeling for terrestrial processes in alpine meadow

The water-heat transfer process between land and atmosphere in Haibei alpine meadow area has been systematically observed. A multi-layer coupling model for land-atmosphere interaction was presented with special attention paid to the moisture transfer in leaf stomata under unsaturated condition. A profound investigation on the physical process of turbulent transfer inside the vegetation has been performed with a revised formula of water absorption for root system. The present model facilitates the study of vertically distributed physical variables in detail. Numerical simulation was conducted according to the transfer process of Kinesia humility meadow in the area of Haibei Alpine Meadow Ecosystem Station, CAS. The calculated results agree well with observation.

CAS-1模拟月壤

模拟月壤是与月球月壤具有相似的矿物组成、化学成分和物理力学性质的地球物质,是月球样品的地球化学复制品.长白山龙岗火山群金龙顶子火山喷发的四海火山渣具有与阿波罗14号采集的月球样品相似的化学和矿物组成,并含有20%～40 %的玻璃物质.以四海火山渣为初始物质,研制成功CAS-1模拟月壤,并测量了CAS-1模拟月壤的主量和微量元素组成、矿物组成、密度、颗粒形态、粒度分布、抗剪性和复介电常数等参数.结果表明,CAS-1模拟月壤与Apollo 14号采集的月球样品具有相似的化学成分、矿物组成和物理力学性质,是一种理想的低钛玄武岩质模拟月壤.