排序方式: 共有93条查询结果,搜索用时 15 毫秒
81.
82.
83.
Photostimulated luminescence was observed in X-ray irradiated BaBrCl doped with Eu^2 + . It shows an emission band that peak at 413 nm, and two difference absorption spectra (DAS) bands that peak at - 550 nm and 675 nm respectively. The stimulation energy is lower than that of BaFX:Eu^2+ (X = Cl, Br), and matches the cheaper, more portable, and more convenient semiconductor laser better. The results indicate that BaBrCl : Eu^2+ shows positive potential as a promising X-ray storage phosphor for practical utilization. 相似文献
84.
85.
Europium doped MBrCl (M=Ca, Sr, and Ba) phosphors were prepared by solid state reaction in reductive atmosphere. Photolu-minescence (PL), photostimulated luminescence (PSL) after X-ray irradiation and optical absorption studies of MBrCl:Eu2+ (M=Ca, Sr, and Ba) revealed that: (1) blue light emission, under the excitation of 300 nm, was observed in all these phosphors; (2) the shape of the emission spectra in CaBrCl:Eu2+ could be changed by varying the bromine/chlorine ratio during synthesis, while that in SrBrCl:Eu2+ and BaBrCl:Eu2+ showed no change; and (3) PSL was observed in SrBrCl:Eu2+ and BaBrCI:Eu2+ after X-ray irradiation. Difference absorption spectrum (DAS) in SrBrCl:Eu2+ showed two broad bands centered at about 470 and 570 nm, and DAS in BaBrCI:Eu2+ showed two bands at about 550 and 675 nm, respectively. This enabled the use of He-Ne laser (633 nm) or even semiconductor light-emitting diodes (LED) instead of gas lasers for photostimulation. 相似文献
86.
87.
我们应该将一个什么样的地球带入21世纪?ISO14000系列标准的颁布,为企业的环境管理提供了一个准则和思路.该到人类行动的时候了. 相似文献
88.
介绍73000t水压机密封的设计形式及使用效果。将原来的面密封改为线密封后,磨损明显减小,使用周期大大延长。 相似文献
89.
销售型电子商务企业配送中心选址方法初探 总被引:3,自引:0,他引:3
通过分析销售型电子商务企业配送的特殊性和传统配送中心选址方法在解决此类问题的不足之处,提出将所需配送的总区域划分成若干个连续的小区域,建立虚拟"配送点"的方法,从而将配送地点、时间和数量都随机的顾客需求转换成固定区域顾客需求模型,随后通过配送中心选址位置与其配送成本之间的关系再次建立模型得到配送中心的布局和数量,并进一步探讨参数确定和计算步骤. 相似文献
90.
采用连续Nd:YVO4激光器作为泵浦源,在室温下实现了PPMgLN晶体准相位匹配,获得了连续内腔光学参量振荡。获得的光参量阈值仅为3W(808nm);在泵浦光功率为5 W、PPMgLN极化周期为31.5μm时,获得了365 mW、2.95μm的中红外连续激光输出和312 mW、1.66μm信号光输出,总光光转换效率达到13.3%。通过改变晶体周期,实现了2.95~4.16μm闲频光和1.43~1.66μm信号光的宽带可调谐输出。此连续中红外光参量振荡器结构简单紧凑,效率高,将是未来产生3~5μm中红外激光光源的重要方法之一。 相似文献