排序方式: 共有335条查询结果,搜索用时 46 毫秒
91.
采用燃烧法制备出Ca12Al14O33:Eu^2+和Ca12Al14O33:Eu^2+,Re^3+(Re=Dy,La,Nd)靛蓝光长余辉发光粉。分别利用XRD和FE—SEM对产物的物相结构和形貌进行了表征,用光致发光测试(PL)和余辉衰减曲线对样品的发光性能进行了分析。结果表明上述长余辉发光粉的晶体结构属于体心立方相七铝酸十二钙;所制备的Ca12Al14O33:Eu^+、Ca12Al14O33:Eu^2+,Dy^3+、Ca12Al14O33:Eu^2+,La^3+和Ca12Al14O33:Eu^2+,Nd^3+长余辉发光粉的发射光谱均呈宽发射谱带,波长范围为390~530nm,发光峰值也均位于443nm;产物在紫外线或紫色光激发后发射靛蓝光;余辉时间分别为238,184,168和9120s. 相似文献
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采用传统的熔融淬冷法在空气气氛下成功制备了Ce^3+-Tb^3+共掺的含有新型立方相Na Lu F4纳米晶的微晶玻璃.通过XRD分析可知微晶玻璃中析出的是与立方相Na YF4同构的新型立方相Na Lu F4纳米晶.利用TEM观察到纳米晶粒均匀地分布在玻璃基质中,大小约为20 nm.利用荧光光谱及寿命曲线系统地研究了样品的荧光特性.在315 nm近紫外光激发下,通过有效的能量传递,在Ce^3+-Tb^3+共掺样品中不仅得到了Ce^3+的近紫外光发射,还得到了Tb^3+的黄绿光发射.另外,析晶之后,共掺样品的发光强度得到了增强,这可以归因于部分稀土离子进入到了析出的立方相Na Lu F4纳米晶中.研究结果表明,该微晶玻璃是一种优异的发光基质材料,在光电子领域中具有潜在的应用价值. 相似文献
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A new type of highly selective aptamer-labeled fluorescent silica nanoparticles [Apt-tris(2,2'-bipyri- dyl)ruthenium(II)@SiO2 NPs] were prepared through the reverse microemulsion method by using prolonged fluorescence lifetime ruthenium complexes of tris(2,2'-bipyri- dyl)ruthenium(II) (Ru(bpy)2+) as the source of the fluorescence for cellular prion protein imaging. Investigations showed that the newly prepared Ru(bpy)32+@Si02 NPs possessed superior advantages of strong fluorescence, low toxicity, and easy surface modification for bioconjugation. Cell imaging experiments indicated that Apt- Ru(bpy)32+@SiO2 NPs had great tendency to human bone marrow neuroblastoma cells (SK-N-SH cells), since they can express large amount of prion protein on the surface of the cell, while in HeLa cells this phenomenon disappeared for the reason that HeLa cells cannot express prion proteins. 相似文献
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李梅芳 《科技情报开发与经济》2014,(6):120-122
阐述了高校图书馆科技查新服务工作的基本要求、查新员应具备的专业素质以及准确高效的检索策略的制定,探讨了高校图书馆科技查新工作业务的拓展。 相似文献
95.
Here the effect of solid retention time (SRT) on the concentration of the mixed liquor suspend solid (MLSS), the sludge characteristics, the content of extra-cellular polymeric substances (EPS), the viscosity of mixed liquor and effluent quality in the immersed membrane bioreactor (IMBR) was investigated. The results indicate that the increase of the EPS content is the main reason for the increase of mixed liquor viscosity, the former is positively correlated with the latter (R^2 = 0.9751). The size distribution profile of particles in the mixed liquor presents double-peak shape at SRT more than 30 days. The filtration resistance of membrane in IMBR is mainly caused by the tiny particles and the viscosity of the mixed liquor. In this study, the extension of SRT can hardly affect the removal efficiency of Chemical Oxygen Demand (COD) and NH4^+-N, and when SRT is below 30 days, silt density index (SDIIs) is less than 3, the effluent can be deeply treated by using reverse osmosis system (RO) or nano-filtration system (NF). The method of controlling SRT is put forward by analyzing the relationship between SRT and the minimum generation-time of dominant bacteria (at the maximum specific growth rate under the operation temperature). 相似文献
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王会 《萍乡高等专科学校学报》2008,25(5):114-116
本文拟从五个方面对"不大+V/A"格式作一简单探讨:(一)"不大"的性质;(二)"不大"的两种格式意义;(三)"V/A"的进入条件;(四)语用否定的问题;(五)与"不太"的比较。 相似文献
97.
在VC++中利用API实现多线程编程实例 总被引:1,自引:0,他引:1
32位Windows环境下的Win32 API提供了一些多线程应用程序开发所需要的接口函数,本文介绍了一种在Visual C++中利用Win32 API编制多线程程序的实例,有助于加深对Windows多线程编程技术的认识及理解. 相似文献
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