在基础无机化学实验教学中培养学生自主学习能力

自主学习能力的培养是开发学生创新思维、增强独立研究能力的基础,本文通过剖析基础无机化学实验教学中存在的问题,结合大一新生在学习过程中暴露出来的问题,探讨了如何在基础无机化学实验教学的不同阶段,在实验教学的各个环节中,采取不同的教学方式,运用不同的教学手段,帮助学生树立自主学习意识,提高自主学习能力,为新世纪高素质、创新性人才的培养奠定良好的基础。     

YPO4/Eu3+微米束的尿素辅助水热合成及其发光性能

以Y( NO3)3、Eu( NO3)3和(NH4)2HPO4为原料,尿素作辅助剂,采用水热法成功制备出束状YPO4/Eu3+荧光粉.利用X射线粉末衍射仪、透射电镜、荧光光谱仪等研究了产物的晶体结构、形貌及发光特性;基于透射电镜分析探讨了YPO4/Eu3+微米束结构的形成机理.结果表明:YPO4/Eu3+属于四方晶系,空...     

Ag-catalyzed Synthesis of Tb(BO2)3 Nanorods

Well-crystallized with excellent luminescent properties, Tb(BO₂)₃ nanorods were first suc-cessfully synthesized by a simple solid-state method with Ag as catalyst. The result of X-ray diffraction showed that the Tb(BO₂)₃ nanorods could be well-crystallized at 700 oC. As-prepared straight nanorods of Tb(BO₂)₃ had the typical diameters in the range of 100-200 nm, the thickness of 30-50 nm and the lengths up to 3 μm by transmission elec-tron microscopy and the corresponding selected area electron diffraction indicated that the nanorod calcined at 700 oC was single-crystalline. Based on the fact that Ag nanoparti-cles attached to the tips and middles of the Tb(BO₂)₃ nanorods, a growth model of the Tb(BO₂)₃ nanorods was proposed. Photoluminescence spectra under excitation at 369 nm showed that these Tb(BO₂)₃ phosphors had a green emission at 546 nm, which is ascribed to ⁵D₄→⁷F₅ transition. The effect of calcining temperature on the structures, morphologies, and luminescent properties of Tb(BO₂)₃ phosphors were studied.     

双金属RuM（M=Co，Ni）合金纳米粒子负载于MIL-110（Al）：协同催化氨硼烷水解释氢

By adjusting various Ru/M (M=Co, Ni) molar ratios, a series of highly dispersed bimetallic RuM alloy nanoparticles (NPs) anchored on MIL-110(Al) have been successfully prepared via a conventional impregnation-reduction method. And they are first used as heterogeneous catalysts for the dehydrogenation reaction of AB at room temperature. The results reveal that the as-prepared Ru₁Co₁@MIL-110 and Ru₁Ni₁@MIL-110 exhibit the highest catalytic activities in different RuCo and RuNi molar ratios, respectively. It is worthy of note that the turnover frequency (TOF) values of Ru₁Co₁@MIL-110 and Ru₁Ni₁@MIL-110 catalysts reached 488.1 and 417.1 mol H₂ min^-1 (mol Ru)^-1 and the activation energies (E_a) are 31.7 and 36.0 kJ/mol, respectively. The superior catalytic performance is attributed to the bimetallic synergistic action between Ru and M, uniform distribution of metal NPs as well as bi-functional effect between RuM alloy NPs and MIL-110. Moreover, these catalysts exhibit favorable stability after 5 consecutive cycles for the hydrolysis of AB.     

纳米稀土磷酸盐(Gd,Y)PO4:Tb的室温固相合成及发光性能

三基色荧光灯用绿色发光材料,其发光效率对总的光通量影响很大[1],因而探索不同体系的绿色发光材料的合成将意义重大.由于Tb3 离子具有较好的特征绿色发射,所以研究铽的不同体系绿粉一直是人们所感兴趣的课题[2].稀土磷酸盐发光材料具有发光亮度高,合成温度适中,色坐标x值大等优点,因而成为当前材料科学的热门[3-5].     

铽异烟酸哌嗪三元配合物的合成及其荧光性能

以醋酸铽,异烟酸和哌嗪为原料,合成了铽异烟酸哌嗪三元固体配合物,其结构经UV-vis,IR,TC-DTA和元素分析表征,并用荧光光谱测定了其荧光性能.     

石墨探针技术／石墨炉原子吸收光谱测定人发中痕量锰

本文采用探针原子化技术对痕量锰进行了一系列条件试验，试验结果表明，石墨探针炉法具有灵敏度高，检出限低，重现性好，简便快速等特点，应用于人发中痕量锰的测定，结果满意。     

La2Zr2O7:Eu3+纳米棒的合成、表征及其荧光性能

采用传统固相法和水热法成功地制备出棒状La₂Zr₂O₇:Eu³⁺荧光粉. 利用X射线粉末衍射仪、透射电镜和荧光光谱仪等分析了产物的结构、形貌和发光特性. 结果表明红色荧光粉La₂Zr₂O₇:Eu³⁺有良好的晶相,属于立方结构,空间点群为Fd3m; 其形貌主要为纳米棒, 平均直径约47 nm, 长度为50～700 nm. 并对纳米棒的生长机理进行了探讨. 在466 nm蓝光激发下,La₂Zr₂O₇:Eu³⁺荧光粉能发射出Eu³⁺的特征红色荧光,发射主峰位于616 nm处,归属于Eu³⁺的⁵DO_→⁷F2_{超灵敏电偶极跃迁.此外,在产物的发射光谱中能够观察到⁵D}1_→⁷FJ _{(J=0, 1, 2)跃迁和⁵D}1_→⁷FJ _{(J=1, 2, 4)跃迁的劈裂峰,这说明Eu³⁺处在低对称性的晶体场格位中.}     

变时滞Hopfield神经网络的全局指数稳定性

本文研究了一类具有变时滞Hopfield神经网络的稳定性问题.利用时滞微分不等式方法,获得了几个关于该网络的全局指数稳定性与时滞无关的充分条件,并且给出了此类网络的收敛指数的估计,推广了已知文献的结果.最后给出数值例子证明结论的有效性.     

SiO2包覆铕（Ⅲ）配合物的荧光纳米粒子合成与性质

以前驱物pAB-DTPAA-APTEOS、正硅酸乙酯(TEOS)和三氯化铕(EuCl3)等为原料,采用油包水(W/O)的反相微乳液法,在正硅酸乙酯(TEOS)和3-氨丙基三乙氧基硅烷(APTEOS)的共同水解下,制备出新型的SiO2包覆铕配合物荧光纳米粒子Eu-pAB-DTPAA-AP-SiO2。运用TEM、IR、UV-Vis、荧光光谱等技术对荧光纳米粒子进行了表征。TEM结果表明:包覆体呈球形,分散均匀,平均粒径为40nm。纳米粒子与配体、前驱物的紫外吸收谱相比较,峰位发生了一定的红移,表明通过反相微乳液法得到的固体粉末与EuCl3反应后,已经生成配合物Eu-pAB-DTPAA-AP-SiO2。红外光谱研究表明,在801cm-1出现νSi—C的伸缩振动峰,471cm-1处出现νEu—O的伸缩振动峰。由此证实Eu-pAB-DTPAA-AP-SiO2配合物的存在。荧光光谱分析表明,纳米粒子Eu-pAB-DTPAA-AP-SiO2表现出较好的荧光性能,位于592,615,689nm的发射峰分别归属于Eu3 离子的5D0→7F1、5D0→7F2和5D0→7F4跃迁,其中最强峰615nm属于Eu3 的特征跃迁发射。作为一种新型的荧光试剂,该纳米粒子具有粒径小,亲水性强,荧光强度大,且表面的氨基能方便地与生物分子偶联,故可作为优良的时间分辨荧光标记物用于各种高灵敏生物检测技术中。