Cd3Al2Ge3O12: Mn2+磷光体的发光和长余辉性能

采用传统的高温固相法合成了Cd₃Al₂Ge₃O₁₂: Mn²⁺长余辉发光材料, 利用X射线粉末衍射仪、荧光光谱仪、热释光谱计量仪等手段对粉末样品进行了表征。研究了以Zr⁴⁺离子作为辅助激活剂离子, 对发光材料Cd₃Al₂Ge₃O₁₂: Mn²⁺余辉性能的影响。分析结果表明, 样品位于500~700 nm的黄光宽带发射峰源于Mn²⁺的⁴T₁(⁴G)→⁶A₁(⁶S)跃迁发射结果。并且观察到了由Cd₃Al₂Ge₃O₁₂基质向激活剂离子Mn²⁺的能量传递。共掺杂Zr⁴⁺离子后样品发射峰位没有明显变化, 但是余辉亮度衰减曲线表明适量的Zr⁴⁺离子掺杂可延长Cd₃Al₂Ge₃O₁₂: Mn²⁺的余辉时间。通过对热释光谱的分析, 解释了双掺杂荧光粉余辉性能增强的原因, Zr⁴⁺的掺杂在材料中引入了深度更为合适的缺陷陷阱, 可有效存储光能, 增强余辉的时间和强度。     

分子印迹固相萃取-液相色谱联用法测定3种新烟碱类农药的残留

以噻虫啉为模板分子制备了对吡虫啉、氯噻啉、噻虫啉具有特异性识别的分子印迹聚合物。功能单体与模板分子最佳摩尔比为:n(噻虫啉)∶n(甲基丙烯酸)∶n(苯乙烯)=1∶4∶4。动态吸附和选择性吸附表明,此印迹聚合物能够对目标物快速吸附,且有很好的选择性。Scatchard分析表明,此印迹聚合物对吡虫啉、氯噻啉、噻虫啉最大吸附量分别为31.7,36.7和45.3 mg/g。用此印迹聚合物作为固相萃取吸附剂处理加标样品,目标物的回收率为80.2%~98.8%,RSD为1.2%~4.5%(n=3)。本方法用于实际样品检测,获得了满意的结果。     

Weak Commutative Pseudoeffect Algebras

As noncommutative generalizations of effect algebras, we introduce weak commutative pseudoeffect algebras. In this paper, we prove that the generalized pseudoeffect algebras can be unitized if and only if they are weak commutative. Then we discuss the relationships between weak commutative pseudoeffect algebras and weak commutative generalized pseudoeffect algebras. We prove that the category of weak commutative pseudoeffect algebras is a reflective subcategory of weak commutative generalized pseudoeffect algebras. Similarly, we introduce weak commutative pseudodifference posets and show the relationships between weak commutative pseudoeffect algebras and weak commutative pseudodifference posets.     

Femtosecond filamentation in argon and higher-order nonlinearities

We numerically investigate the femtosecond filamentation dynamics in argon by considering the higher-order nonlinearities measured by a recent experiment. Our result indicates that, instead of plasma, these higher-order nonlinearities can provide main defocusing effect as shown by a recent theoretical work. However, when the higher-order nonlinearity is so strong to provide a main defocusing effect, some phenomena inconsistent with previous experiments such as pulse splitting and pulse self-compression can appear. Therefore, we infer that the values of higher-order nonlinear coefficients are overestimated, and the plasma should be the defocusing mechanism at least in the argon filament.     

Dual roles of amphiphilic triblock copolymer P123 in synthesis of α-Fe nanoparticle/ordered mesoporous silica composites

A simple and effective method for in situ synthesis of α-Fe nanoparticle/ordered mesoporous silica (OMS) composites is reported. Evaporation induced self-assembly (EISA) and carbothermal reduction (CR) are strategically combined by using amphiphilic triblock copolymer P123 as not only a template and but also a precursor of carbon material. P123 plays dual roles in assembly of mesostructure and reduction of ferric species. Thermogravimetric analysis-mass spectrometer was used to investigate the pyrolysis process of the wet gels. The synthesized composites were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscope (XPS) and N₂ adsorption. The results showed that the composites possess ordered hexagonal mesoporous structure and the α-Fe nanoparticles with about 16 nm were well dispersed in mesoporous matrix. The carbon material resulting from P123 can reduce ferric species to α-Fe nanoparticles at 800 °C. Moreover, the formation mechanism for Fe nanoparticles in OMS matrix is proposed.     

纳米银米表面等离子激元增强上转换发光

上转换纳米发光材料因发光效率普遍较低限制了其在应用领域的进一步发展。利用贵金属的局域表面等离子体共振特性调控发射体的局域场成为提高上转换纳米粒子发光性能的有效途径之一。在这个工作中,我们利用合成工艺简单的贵金属米状结构,通过调控上转换纳米颗粒周围的局域场,实现了上转换发光强度的大幅提高。结合三维有限元方法研究了在实际薄膜中Ag米之间可能出现的不同接触方式对所产生的局域场增强效果的影响,同时证实这种局域等离激元耦合所引起的电磁场增强是提高上转换发光性能的重要因素,并且获得了上转换发光将近百倍的增强效果。最后,通过调控等离子层和发光层的厚度,实现上转换发光性能的进一步优化。     

XRD法测定沸石分子筛中硅铝比

用X射线衍射外推函数法测定NaY超稳分子筛的晶胞参数，用^29Si、^27Al固体NMR方法测定分子筛骨架中的硅铝比，提出了NaY超稳分子筛硅铝比与晶胞参数关联的经验公式。通过测定分子筛的晶胞参数即可得到NaY超稳分子筛的硅铝比。该方法测得的NaY超稳分子筛硅铝比，比通常采用的化学分析方法省时、简便、重复性好。     

Robust stabilization control design for multivariable nonlinear uncertain systems

The paper develops a new control technique for multivariablenonlinear systems in the presence of uncertainties and externaldisturbances. The proposed design method does not require thatthe uncertainties should satisfy matching conditions; nor doesit require that the nominal system should be stable or prestabilized.The robust-control strategy is established using concepts fromvariable-structure theory and is based on Lyapunov stabilitytheory. The control possesses a quite simple structure whichis related to the given uncertainty bounds.     

关于1-序列商映射

引进了1-序列商映射，证明了1-序列商映射象保持sm-第一可数空间．作为这一结果的一个应用，本文证明了几乎开，闭映射保持度量空间，g-度量空间，sm-度量空间．此外本文还证明了度量空间上的1-序列商，紧映射是1-序列覆盖映射．这些结果改进并推广了广义度量空间映射象的有关理论．     

碱式碳酸铜在空气中的热分解动力学

用羞热分析（DTA）和热重分析（TG）测定了碱式碳酸铜Cu3（OH）2CO3在空气中的热分解曲线，运用X-射线粉末衍射（XRD）、透射电镜（TEM）等技术对碱式碳酸铜热重分解产物进行了表征。实验结果表明，碱式碳酸铜在空气中分解生成粒径约为10nm的CuO，用Friedman法和Flynn-wall-Ozawa（FWO）法求取了Cu2（OH）2CO3热分解的活化能为175．53kJ／mol，并用多元线性回归给出了分解过程的可能机理函数。