Organocatalytic Enantioselective Synthesis of Atropisomeric Aryl‐p‐Quinones: Platform Molecules for Diversity‐Oriented Synthesis of Biaryldiols

Presented here is a class of novel axially chiral aryl‐p‐quinones as platform molecules for the preparation of non‐C₂ symmetric biaryldiols. Two sets of aryl‐p‐quinone frameworks were synthesized with remarkable enantiocontrol by means of chiral phosphoric acid catalyzed enantioselective arylation of p‐quinones by central‐to‐axial chirality conversion. These aryl‐p‐quinones were then used to access a wide spectrum of highly functionalized non‐C₂ symmetric biaryldiols with excellent retention of the enantiopurity.     

紫外熔石英元件高精度低缺陷控形控性制造技术研究进展

传统的紫外熔石英元件加工方法本身会引入各类制造缺陷,需要后期加工来消除前期加工带来的缺陷,限制了熔石英元件的加工质量和加工效率。针对这些问题,课题组提出了采用磁流变、离子束、保形光顺和流体动压抛光等可控柔体加工技术提升熔石英元件的加工效果,并开展了相关研究。主要介绍了课题组在关键技术上取得的重要进展,包括亚纳米精度表面控形制造技术、纳米精度本征表面控性生成方法、熔石英元件高精度低缺陷组合工艺与设备等一系列关键技术。通过探讨关键技术及其发展现状,为未来紫外熔石英元件高精度低缺陷制造技术的发展提供参考。     

Eu^3+激活氟氧硼酸锗酸盐闪烁玻璃的发光性能

采用传统高温熔融法合成了玻璃组成为B2O3-GeO2-15GdF3-(40-x)Gd2O3-xEu2O3(0≤x≤10)的Eu^3+激活氟氧硼酸锗酸盐闪烁玻璃。在硼锗酸盐玻璃基质中,Gd2O3和GdF3稀土试剂的总含量高达55%,从而确保其密度高于6.4 g/cm^3。闪烁玻璃的光学性能通过光学透过光谱、光致发光光谱、X射线激发发射(XEL)光谱和荧光衰减曲线来表征。玻璃中Gd^3+→Eu^3+离子的能量传递通过激发光谱、发射光谱和Gd^3+-Eu^3+离子间距得到证明,同时也确定了在紫外线和X射线激发下Eu^3+激活氟氧硼酸锗酸盐闪烁玻璃的最佳浓度。Judd-Ofelt理论分析了玻璃中Eu―O键的共价性随Eu^3+掺杂浓度增加而显著增强。Eu^3+激活氟氧硼酸锗酸盐闪烁玻璃在80~470 K温度范围内荧光衰减曲线和发射光谱的温度依赖关系最终证实了其具有较好的发光稳定性。     

埋层界面和空气表面和频光谱信号贡献的调控

本文研究表明通过膜厚控制和表面等离激元增强方法可有效区分隐藏界面和空气表面的和频振动光谱信号. 以氟化钙基底支撑的PMMA薄膜为模型，观察到隐藏界面和空气表面对和频信号贡献的变化. 通过监控羰基和甲基伸缩振动基团，发现薄PMMA膜的和频信号来自PMMA/空气表面的化学基团-CH₂、-CH₃、-OCH₃和C=O，而厚PMMA膜的和频信号则来自基底/PMMA埋层界面的-OCH₃和C=O基团. 随制膜浓度增大，埋层界面C=O基团的取向角从65°下降到43°，且浓度大于或等于0.5 wt%时，取向角等于45°±2°. 相比之下，空气表面C=O的取向角落在21°∽38°之间. 在金纳米棒存在条件下，表面等离激元可以极大地增强和频信号，尤其是来自埋层界面信号.     

Some New Regularity Criteria for the 2D Euler-Boussinesq Equations Via the Temperature

In this paper, we consider the Euler-Boussinesq equations in dimension two. Some new regularity criteria via the temperature are established by making use of the Littlewood-Paley technique and the new logarithmic Gronwall inequality.     

A Robust Mixed-Lanthanide PolyMOF Membrane for Ratiometric Temperature Sensing

Temperature sensors play a significant role in biology, chemistry, and engineering, especially those that can work accurately in a noninvasive manner. We adopted a photoinduced post-synthetic copolymerization strategy to realize a membranous ratiometric luminescent thermometer based on the emissions of two lanthanide ions. This novel mixed-lanthanide polyMOF membrane exhibits not only the integrity and temperature sensing behaviour of the Ln-MOF powder but also excellent mechanical properties, such as flexibility, elasticity, and processability. Moreover, the polyMOF membrane shows remarkable stability under harsh conditions, including high humidity, strong acid and alkali (pH 0–14), which allowed the mapping of temperature distributions in extreme circumstances. This work highlights a simple strategy for polyMOF membrane formation and pushes forward the further practical application of Ln-MOF-based luminescent thermometers in various fields and conditions.     

A theoretical study on the pure and doped ZnO nanoclusters as effective nanobiosensors for 5-fluorouracil anticancer drug adsorption

The electronic sensitivity and effectiveness of the pristine, Fe,- Mg-, Al- and Ga-doped ZnO nanoclusters interacted with 5-fluorouracil (5-FU) anticancer drug are theoretically investigated in the gas phase using the B3LYP/wB97XD density functional theory calculations with LANL2DZ basis set. It is concluded that 5-FU adsorption on the doped nanoclusters has relatively higher adsorption energy as compared with the pristine zinc oxide. A number of thermodynamic parameters, such as band gap energy (E_g), adsorption energy (E_ad), molecular electrostatic potential, global hardness (η) and density of electronic states, are attained and compared. Also, calculated geometrical parameters and electronic properties for the studied systems indicate that Mg- and Ga-doped Zn₁₂O₁₂ present higher sensitivity to 5-FU compared with the pristine nanocluster. Theoretical results reveal that adsorption of 5-FU on the doped nanoclusters is influenced by the electronic conductance of the nanocluster. Therefore, Mg- and Ga-doped ZnO can be considered as promising nanobiosensors for detection of 5-FU in medicine.