Doping effects of CuO on the sintering behavior and electrical properties of 0.94(Bi0.5Na0.5)TiO₃–0.06(BaTiO3)–xCuO (BNT–BT6–xCu) lead-free piezoceramic obtained by the conventional solid-state reaction method were investigated. Regarding the undoped system, it is already known that it presents the best densification values when it is sintered at 1150∘C, however, the doped system was sintered at 1150∘C, 1100∘C, 1050∘C, 1025∘C, and 975∘C to determine the effect of Cu on the densification process. Therefore, it was obtained that the CuO-doped samples sintered at 1050∘C presented the highest density values and therefore were the ones chosen to perform the characterization tests together with the undoped system. The samples were characterized using X-ray diffraction (XRD), Raman microspectroscopy, and scanning electron microscopy (SEM) analysis, whereas the ferroelectric and dielectric properties were evaluated by means of ferroelectric hysteresis loops and impedance spectroscopy studies. As a result, the addition of CuO allowed an improvement in sinterability and densification, with the subsequent grain growth, and the improvement of the piezoelectric coefficient (d33).Doping effects of CuO on the sintering behavior and electrical properties of 0.94(Bi0.5Na0.5)TiO₃–0.06(BaTiO3)–xCuO (BNT–BT6–xCu) lead-free piezoceramic obtained by the conventional solid-state reaction method were investigated. Regarding the undoped system, it is already known that it presents the best densification values when it is sintered at 1150∘C, however, the doped system was sintered at 1150∘C, 1100∘C, 1050∘C, 1025∘C, and 975∘C to determine the effect of Cu on the densification process. Therefore, it was obtained that the CuO-doped samples sintered at 1050∘C presented the highest density values and therefore were the ones chosen to perform the characterization tests together with the undoped system. The samples were characterized using X-ray diffraction (XRD), Raman microspectroscopy, and scanning electron microscopy (SEM) analysis, whereas the ferroelectric and dielectric properties were evaluated by means of ferroelectric hysteresis loops and impedance spectroscopy studies. As a result, the addition of CuO allowed an improvement in sinterability and densification, with the subsequent grain growth, and the improvement of the piezoelectric coefficient (d33).

提出一种反抛物线型掺铒光纤,该光纤可以实现二阶模式组中简并矢量模式的有效分离。将其作为光纤激光器的增益介质,采用数值方法分析光纤中饵离子掺杂分布、饵离子掺杂浓度、光纤长度和抽运光功率对掺饵光纤激光器输出模式的影响。通过在光纤不同环形区域内掺杂饵离子,可以实现TE01模式或TM01模式的单独输出,并且激光器的斜率效率分别高达67.4%和63.5%,输出模式纯度分别高达99.97%和99.99%。所提的基于反抛物线型掺铒光纤的激光器具有斜率效率高、输出模式纯度高的优势,该光纤激光器可应用于高功率激光器、光纤通信和光纤传感等领域。

环状光敏手性剂不仅具有较好的光稳定性, 且可以通过控制环张力而对分子的光异构化速率进行调控, 但其与液晶分子间的相容性有待提高。本文通过在联萘基团的6,6′位点处引入与液晶分子结构相似的棒状刚性取代基, 制备了BPO5BA联萘偶氮苯环状光敏手性剂, 探究了其在溶液和液晶中的光异构化过程, 并通过计算Teas溶解度参数对手性剂分子与液晶分子间的相容性进行探究。通过研究发现, 与Azo-o-Bi分子相比, BPO5BA分子中由于刚性取代基的引入, 使偶氮苯基团的转动受到了环张力和刚性的限制, 导致该分子在溶剂和液晶中的光异构化程度较低。此外, BPO5BA分子具有与Azo-o-Bi分子相反螺旋方向和较大的β值, 且与液晶分子间的相容性较好。

为了改善有机电致发光器件的性能，利用CsN3作为N掺杂剂，以B3PYPPM为电子传输材料，制备了基于绿色磷光材料Ir(ppy)3的高效率有机电致发光器件。针对不同N掺杂浓度和掺杂厚度的器件进行研究，最终得到最佳N掺杂器件B，器件结构为ITO/HAT-CN(5 nm)/TAPC(70 nm)/TCTA∶Ir(ppy)3(15%,20 nm)/B3PYPPM(17 nm)/B3PYPPM∶CsN3(10%,63 nm)/Al。实验结果表明，浓度与厚度适当的N掺杂器件能有效提高器件的电流效率和功率效率。CsN3作为一种高效的N掺杂剂，与电子传输材料B3PYPPM掺杂后，有效地降低了电子的注入势垒，增加了电子注入，提高了电子迁移率，改善了电子的注入和传输能力，使载流子更加平衡，从而降低了器件的开启电压和驱动电压，有效地提高了电流效率和功率效率。最佳N掺杂器件B开启电压仅为2.1 V，最大电流效率和功率效率分别为67.0 cd/A、91.1 lm/W。值得注意的是，在1 000 cd/m2亮度下，最佳N掺杂器件B的功率效率仍能达到80.1 lm/W。

X-ray drive asymmetry is one of the main seeds of low-mode implosion asymmetry that blocks further improvement of the nuclear performance of “high-foot” experiments on the National Ignition Facility [Miller et al., Nucl. Fusion 44, S228 (2004)]. More particularly, the P2 asymmetry of Au's M-band flux can also severely influence the implosion performance of ignition capsules [Li et al., Phys. Plasmas 23, 072705 (2016)]. Here we study the smoothing effect of mid- and/or high-Z dopants in ablator on Au's M-band flux asymmetries, by modeling and comparing the implosion processes of a Ge-doped ignition capsule and a Si-doped one driven by X-ray sources with P2 M-band flux asymmetry. As the results, (1) mid- or high-Z dopants absorb hard X-rays (M-band flux) and re-emit isotropically, which helps to smooth the asymmetric Mband flux arriving at the ablation front, therefore reducing the P2 asymmetries of the imploding shell and hot spot; (2) the smoothing effect of Ge-dopant is more remarkable than Si-dopant because its opacity in Au's M-band is higher than the latter's; and (3) placing the doped layer at a larger radius in ablator is more efficient. Applying this effect may not be a main measure to reduce the low-mode implosion asymmetry, but might be of significance in some critical situations such as inertial confinement fusion (ICF) experiments very near the performance cliffs of asymmetric X-ray drives.

以三价铕离子为单一铕源, 采用化学共沉淀法制备了二价铕与三价铕共掺杂的SrSO4荧光粉体材料.通过X射线衍射仪、扫描电镜、光致发光谱仪对该荧光粉的晶体结构、形貌、光致发光特性进行分析.研究发现: 所合成的SrSO4粉体材料为二价铕与三价铕共掺杂的SrSO4微晶, 其大小在1~10 μm之间.在325 nm 的紫外光激发下该微晶能发射很强的绛红色荧光, 其光致光谱由一个位于379 nm 的宽发光带和位于575 nm、591 nm和612 nm的三个窄发光带组成.基于局域密度近似的密度泛函理论, 计算了SrSO4的能带结构及其氧缺陷能级, 然后以能带结构为基础讨论了二价铕与三价铕共掺杂SrSO4的发光机理.峰位于379 nm的宽发光带可归因于SrSO4微晶中二价铕离子发光中心的4f65d1→4f7的电子跃迁, 而三个红色窄发光峰分别来自三价铕离子5D0→7F0, 5D0→7F1, 5D0→7F2的电子跃迁.实验表明二价铕与三价铕共掺杂的SrSO4能作为高效的绛红色荧光粉.

本文以磷酸为磷源,通过溶胶水热法制备磷掺杂TiO2,利用Lee和Meisel的方法制备银溶胶,以4-巯基苯甲酸(MBA)为探针分子,通过构建TiO2/MBA/Ag三明治结构,研究磷掺杂二氧化钛对该基底表面增强拉曼(SERS)性能的提升。通过TEM、XRD、XPS、DRS和拉曼光谱图表征二氧化钛的形貌结构、化学组成、光学和拉曼性能,结果表明,制备出的磷掺杂二氧化钛为锐钛矿型纳米颗粒,粒径范围6~12 nm,XPS显示磷以P5+替代了Ti4+,形成O-P-O键掺入TiO2的晶格中,当磷的掺杂量在1.77%时,TiO2/MBA/Ag三明治体系具有最佳的SERS信号,这是因为适量的磷掺杂降低了TiO2的能带间隙,丰富TiO2的表面态,这能促进TiO2向MBA分子的电荷转移。