Highly luminescent europium(III) complexes with naphtoiltrifluoroacetone and dimethyl sulphoxide

The synthesis, luminescence properties, experimental determination and theoretical calculation of the emission quantum yield of Eu(NTA)₃.2L complexes, where NTA is naphtoiltri-fluroacetone and L denotes H₂O or DMSO (dimethyl sulphoxide), were reported. The compounds were characterized by elemental analysis (carbon, hydrogen and europium), thermal analysis, UV-visible absorption and photoluminescence spectroscopies. The experimental quantum yields were determined based on a method previously proposed by Bril and collaborators. The Eu(NTA)₃.2DMSO compound shows a high value for the Ω₂ intensity parameter (35.8 × 10^?20 cm²), reflecting the hypersensitive nature of the ⁵D₀ → ⁷F₂ transition and indicating that the lanthanide ion is in a highly polarizable chemical environment. The experimental quantum yield measured for that compound, 0.75, is one of the highest so far reported for solid-state europium complexes. The theoretical calculations of the quantum yield were carried out by solving an appropriate set of rate equations and by using empirical spectroscopic parameters and energy transfer rates. The theoretical results agree well with the experimental data for both complexes. The photostability of Eu(NTA)₃.2DMSO at 358K was evaluated in order to verify whether this complex can be applied as a phosphor for blue light emitting devices.     

How the Asymmetric Nature of IP Traffic Influences the Cost of the Underlying Optical Layer

In this article the influence of the asymmetric nature of (IP) traffic on the cost of the underlying optical transport network is investigated over a time frame of six years using a realistic traffic forecast for a European fiber-optic network. The currently deployed transport networks contain bidirectional optical line systems and are thus inherently symmetric, although the traffic that has to be conveyed over those networks is asymmetric. This article shows that a cost reduction of up to 38% can be obtained if the bidirectional line systems are replaced by unidirectional ones.     

钾蒸气中的偶极禁戒双光子共振四波混频和混合激发能量转移受激辐射

本文首次报道了由钾分子-原子系统的混合激发和碰撞能量转移过程产生4F→3D受激辐射以及由钾原子的4S→4F偶极禁戒双光子共振产生4F→3D受激辐射和四波混频的研究结果。     

S.I.S.向量随机测度在弱拓扑及相容拓扑下的收敛性

本文主要研究ｓ．ｉ．ｓ．向量随机测度在弱拓扑及相容拓扑下的收敛性,给出了ｓ．ｉ．ｓ．向量随机测度在弱拓扑 容拓扑下的Ｖｉｔａｌｉ－Ｈａｌｍ－Ｓａｋｓ定理,作为应用,我们建立了Ｒ＾１－值有界可测函数关于Ｂａｎａｃｈ空间值ｓ．ｉ．ｓ．向量随机测度的随机积分的收敛定理,并得到了具ｔｙｐｅｐ的Ｂａｎａｃｈ空间中ｓ．ｉ．ｓ．向量随机测度的大数定律及中心极限定理。     

球形BaZnF_4∶Yb,Er纳米颗粒的热分解法合成及其上转换发光性质

采用热分解法制备了Ba Zn F4∶Yb,Er纳米颗粒。通过荧光分光光度计、X射线粉末衍射仪(XRD)和透射电子显微镜(TEM)对样品进行了表征。合成样品的形貌为球形,晶相为四方相,平均粒径为8 nm。当敏化剂Yb3+和激活剂Er3+的掺杂摩尔分数分别为20%和4%时,样品的发光性能较好。绿光和红光发射对应的辐射跃迁分别为Er3+离子的2H11/2→4I15/2(绿光)和4S3/2→4I15/2(绿光),以及Er3+离子的4F9/2→4I15/2(红光)。     

稳态实验考察经模拟道路老化的全配方稀燃Nox捕集催化剂上的Nox还原

Fully formulated lean NOx trap(LNT)catalysts of the type Pt/Rh/BaO/Al2O3 were prepared with and without incorporation of CeO2-ZrO2 in the washcoat,and their NOx reduction behavior was evaluated in steady-state,continuous flow experiments.In the fresh state, the CeO2-ZrO2 addition was found to exert little effect on NOx reduction activity using H2,CO,and NH3 as the reductants.However,after simulated road aging,NOx reduction activity was significantly impaired for the CeO2-ZrO2-free catalyst,whereas the perfo...