氟氧化物玻璃陶瓷中交叉能量传递与荧光防伪的初步研究

研究了Yb³⁺Er³⁺共掺和Er³⁺单掺氟氧化物玻璃陶瓷材 料的稳态发光行为,对氟氧化物玻璃陶瓷(FOV),氟氧化物玻璃(FOG)和氟化物玻璃(ZBLAN) 中Yb³⁺Er³⁺的交叉能量传递效应也进行了细致的研究.发现在377nm 紫外光激发⁴G_11/2能级的情况下,由于Yb³⁺对Er ³⁺的交叉能量传递,仅在 关键词： 交叉能量传递 氟氧化物玻璃陶瓷 荧光防伪     

Improved anti-Stokes energy transfer between rare earth ions in Er（0.5）Yb（9.5）：FOV oxyfluoride vitroceramics explains the strong color reversal

The widely used energy transfer theory is a foundation of luminescence,in which the rates of Stokes and antiStokes processes have the same calculation formula.An improvement on the anti-Stokes energy transfer to explain the fluorescence intensity reversal between the red and green fluorescence of Er(0.5)Yb(9.5):FOV is reported in the present article.The range of the intensity reversal Σ was measured to be 877.Dynamic processes for 16 levels were simulated.A coefficient,the improvement factor of the intensity ratio of Stokes to anti-Stokes processes in quantum Raman theory compared to classical Raman theory,is introduced to successfully describe the anti-Stokes energy transfer.A new method to calculate the distance between the rare earth ions,which is critical for the energy transfer calculation,is proposed.The validity of these important improvements is also proved by experiment.     

Tm~(3+)在氟氧化物玻璃陶瓷中的光谱性质

根据Tm掺杂的氟氧化物玻璃陶瓷的吸收光谱 ,用Judd Ofelt理论计算了强度参量 ,并由此计算了激发能级的自发辐射跃迁几率、辐射寿命、荧光分支比和积分发射截面等光谱参量。     

氟氧化物氟化物五磷酸盐玻璃中Er3+的直接上转换增敏发光的比较

本文研究了ErYb共掺的氟氧化物玻璃 (ErYb:FOG)、氟化物ZBLAN玻璃和五磷酸盐非晶在 966nm半导体激光激发下的直接上转换敏化发光现象。发现有丰富的上转换发光现象 ,这是由于样品中Yb3 的浓度很高 ,Er3 Yb3 ,Yb3 Yb3 离子之间的相互作用和能量传递作用都很强造成的。研究发现ErYb :FOG玻璃的直接上转换增敏发光比磷酸盐大 1 0 0～ 1 0 0 0 0 0倍 ;而很有趣的结果在于氟氧化物玻璃的直接上转换增敏发光与ZBLAN玻璃接近 ;这对于提高频率上转换的综合性能是很有意义的。     

Effect of pre-acid-hydrolysis treatment on morphology and properties of cellulose nanowhiskers from coconut husk

Three different pre-acid-hydrolysis treatments were used to treat coconut husk fibers for preparing cellulose nanowhiskers by sulfuric acid hydrolysis. The effects of those treatments on the morphology and properties of the nanowhiskers were investigated. FTIR was employed to evaluate the change of chemical composition due to different pre-acid-hydrolysis treatments. AFM images showed that there was no significant difference of size of nanowhiskers obtained by different pre-acid-hydrolysis treatment, 2–3 nm of average thickness. The thermal decomposition of nanowhiskers shifted to higher temperatures with removal of hemicellulose and lignin.     

Personal and atmospheric concentrations of ozone in southeastern hyogo prefecture, Japan

Twenty-one data sets composed of readings collected by atmospheric ozone monitors worn by individuals on their clothing and installed outside their home or office were collected using Ogawa passive ozone samplers in southeastern Hyogo prefecture, Japan from September 12 to 13, 2011. The concentrations of personal and outdoor ozone ranged from not detectable to 23.2?ppb and from 4.7 to 38.3?ppb, respectively. The mean concentration of personal exposure to ozone was 3.7?ppb and was significantly lower than that of outdoor ozone (18.5?ppb). This suggests that the concentrations of outdoor ozone affect personal ozone exposure. However, in this study, we found no correlation between the concentrations of personal ozone and the total time spent outdoors or the time of day the individual was outside. In contrast, the mean concentrations of outdoor ozone were similar to those of ozone measured at the 12 nearest Ambient Monitoring Stations (AMSs). However, when the AMS was situated near a main road, the regional ozone levels were underestimated.