Mg3(AlEU)层状氢氧化物的结构与发光性能的研究

本文采用共沉淀法合成了一系列不同Eu3+含量的Mg-Al-Eu三元层状复合金属氢氧化物(LDH).采用X-射线衍射(XRD)、红外光谱(IR)、光致发光光谱(PL)以及热重(TG-DTG)对产物进行表征,发现LDH中Eu3+/Al3+物质的量百分比小于25%时,三元LDH中Eu3+含量的增加对其结晶性没有明显的影响;当Eu3+/Al3+物质的量百分比达到25%时,其结晶质量明显变差.PL分析结果表明,所有样品中出现典型的Eu3+5DO-7FJ(J=1,2,3,4)跃迁所致的红光发射.随Eu3+含量的增加,Eu3+的发射强度明显呈增强趋势;当Eu3+/Al3+物质的量百分比达到25%时,其发射强度明显减弱.由此可知,Mg-Al-Eu LDH结构中,Eu3+/Al3+最佳物质的量百分比为20%.     

Constructing ZnCo2O4@LDH Core–Shell hierarchical structure for high performance supercapacitor electrodes

In this article, ZnCo₂O₄ nanowires deposited with two kinds of typical layered double hydroxides (Ni–Al,Co–Al LDH) are developed via scalable method. Two materials all display core–shell hierarchical structure. High specific capacitance of 2041 F g⁻¹ and 1586 F g⁻¹ are obtained for ZnCo₂O₄@Co–Al LDH and ZnCo₂O₄@Ni–Al LDH,respectively. Combining with active surface and synergistic effect, the role of hierarchical structure in enhancing performance is revealed. Moreover, two all solid state supercapacitors based on fabricated materials as positive electrodes, activated carbon as negative electrodes and PVA–KOH as polymer electrolyte are assembled. The maximum power and energy densities of ZnCo₂O₄@Co–Al LDH//AC are 6200 W kg⁻¹ and 50.1 Wh kg⁻¹, respectively. While the power and energy densities of ZnCo₂O₄@Ni–Al LDH//AC are 3400 W kg⁻¹ and 27.8 Wh kg⁻¹. At last, an energy storage–conversion system, based on solar cell as input device and assembled asymmetric supercapacitor ZnCo₂O₄@Co–Al LDH//AC as output device, is integrated as a self–sustaining power device, indicating its potential in practical applications.     

黄蜀葵花总黄酮对海马神经元缺氧复氧损伤的保护作用

目的: 研究黄蜀葵花总黄酮（total flavones of abelmoschl manihot,TFA）对海马神经元缺氧复氧损伤的保护作用以及可能的内皮衍生超级化因子（endothelium-dependent hyperpolarizing factor,EDHF）相关机制。方法: 采用原代培养的海马神经元建立缺氧4 h/复氧24 h损伤模型,预先在细胞培养上清内加入大鼠脑基底环动脉（basilar artery,BA）环,分别给予乙酰胆碱（acetylcholine,Ach）联合一氧化氮（nitric oxide,NO）合酶抑制剂Nω-nitro-L-arginine-methyl-ester（L-NAME)和前列环素（prostacyclin,PGI2）抑制剂indomethacin（Indo）;TFA联合L-NAME和Indo预处理。检测缺氧/复氧损伤后海马神经元存活率、培养上清液中乳酸脱氢酶（lactate dehydrogenase,LDH）活力的变化;另外,用激光共聚焦法检测细胞内游离Ca²⁺浓度。结果: 与单独应用Ach或者TFA预处理比较,Ach或者TFA联合脑基底动脉环均能明显改善缺氧/复氧后海马神经元存活率的降低,培养上清中LDH活力降低。此外,TFA联合脑基底动脉环抑制海马神经元细胞内游离Ca²⁺的增高,L-NAME及Indo对此结果并无显著影响。结论: TFA对缺氧/复氧致海马神经元损伤有明显的保护作用,其机制可能与促进EDHF释放,抑制细胞内Ca²⁺超载有关。     

Influence of Reaction Time on Growth Behaviours of Mg-Al LDH Films

Mg-Al LDH film was fabricated on anodized magnesium alloy AZ31 by in-situ growth method. The characteristics of the film were investigated by X-ray diffraction (XRD), Fourier transform infrared (FT-IR), scanning electron microscopy (SEM) observation and electrochemical tests. The results showed that the crystallinity of LDH film was increased with reaction time. When the reaction time was more than 12 h, the LDH film had complete crystal layered structure. The anodic oxide film was sealed basically by the growth of LDH nanosheets after 6 h reaction. The corrosion resistance of the films became better with the increasing of reaction time. However, after 12 h reaction, the corrosion resistance of the film decreased. The formation behavior of the Mg-Al LDH film was proposed. That the competitive growth of LDH grains, which contains dissolution and recrystallization, was proposed to explain the change of the growth and corrosion resistance of the Mg-Al LDH film.     

α/γ-氧化铝对合成镁铝水滑石结构性能的影响

为了解α-氧化铝和γ-氧化铝合成镁铝水滑石（LDH）结构性能的差异,以α-氧化铝和γ-氧化铝为原料采用水热法合成了镁铝水滑石α-LDH-2.0和γ-LDH-2.0。通过扫描电镜（SEM）、红外光谱（FT-IR）、拉曼光谱（Raman）、X射线光电子能谱（XPS）、X射线衍射（XRD）、热重分析（TG-DTG）等对α-LDH-2.0和γ-LDH-2.0进行了检测,并将α-LDH-2.0和γ-LDH-2.0用于吸附刚果红的实验。结果表明：γ-氧化铝合成的γ-LDH-2.0板层更无序、结晶度较高,吸附实验中γ-LDH-2.0对刚果红的吸附效果强于α-LDH-2.0,并且适应更广的溶液pH范围,说明使用不同晶型的氧化铝可以调控镁铝水滑石的形貌结构使其高效吸附刚果红。当刚果红质量浓度为100 mg/L、镁铝水滑石添加量为20 mg时,α-LDH-2.0和γ-LDH-2.0对刚果红的吸附量较大,酸性条件更有利于α-LDH-2.0和γ-LDH-2.0对刚果红的吸附,α-LDH-2.0和γ-LDH-2.0去除刚果红的吸附动力学更符合拟二级动力学方程,等温吸附过程符合Langmuir模型。     

纳米双羟基复合金属氧化物协同聚磷酸铵阻燃尼龙-6/聚丙烯燃烧及热降解行为的研究

将纳米双羟基复合金属氧化物 (LDH)与聚磷酸铵 (APP)在一定范围内复配 ,用于尼龙 6/聚丙烯 (PA 6/PP)共混体系可产生良好的协同阻燃效果。实验表明 ,LDH参与了共混阻燃体系的热分解反应 ,催化了PA 6/PP/APP体系的交联、成炭 ;LDH协同阻燃体系的残炭形态致密、光滑、残炭微孔呈闭合状态。协同阻燃作用的机理与LDH和APP热降解过程中产物间的化学与物理作用有关。     

Barrier properties of sulfonated polysulfone/layered double hydroxides nanocomposite membrane for direct methanol fuel cell operating at high methanol concentrations

High performing and cost effective nanocomposite membranes for DMFC application are synthesized by incorporating hygroscopic layered double hydroxides (LDH) particles into sulfonated polysulfone (sPSU). A significant improvement in the dimensional stability as well as in the water and methanol molecular dynamics of the sPSU_LDH composite membrane is observed in comparison with both pristine sPSU and Nafion 212. The strong electrostatic interaction occurring between positively charged LDH platelets and negatively charged polymer chains of sPSU alters the microstructure of the ionic domains, allowing an effective reduction of the methanol permeability whilst improving the proton conductivity. The methanol crossover measurements confirmed that sPSU_LDH membranes are able to withstand high methanol concentration without significant aftermath on the chemical stability of the electrolyte. The features enable the single DMFC assembled with the sPSU_LDH nanocomposite to achieve the remarkable power density of 150 mW cm⁻² at 80 °C in 5 M methanol solution.     

焙烧水滑石对Cr(Ⅵ)的去除性能研究

采用共沉淀法制备了Mg/Al-CO3水滑石,经焙烧得CLDH,用傅里叶红外光谱仪对物相进行表征;利用水滑石焙烧后在一定条件下可重新吸收水和阴离子,从而部分恢复层状结构的结构记忆效应,考察了不同温度焙烧的水滑石去除铬离子[Cr(Ⅵ)]的性能。实验结果表明,400℃下焙烧的水滑石对Cr(Ⅵ)的去除率最高。     

基于电沉积水热法的钢表面Mg-Al-NO3-LDH膜原位生长制备及沉积电位优化

为提升建筑用钢的耐久性,通过电沉积法在钢表面形成层状双氢氧化物（LDH）晶核,再通过水热反应让LDH晶核生长成形成致密的Mg-Al-NO₃-LDH膜,分析了电沉积电位对钢基底表面LDH膜生长的影响,讨论了LDH膜的形成机理.结果表明,当电沉积电位为-1.4 V（相对于Ag/AgCl电极）时,LDH纳米片聚集堆叠致密,形成的LDH膜结构最为密实,实现了对钢基底良好的锈蚀防护.     

Interactions between S100A9 and Alpha-Synuclein: Insight from NMR Spectroscopy

S100A9 is a pro-inflammatory protein that co-aggregates with other proteins in amyloid fibril plaques. S100A9 can influence the aggregation kinetics and amyloid fibril structure of alpha-synuclein (α-syn), which is involved in Parkinson’s disease. Currently, there are limited data regarding their cross-interaction and how it influences the aggregation process. In this work, we analyzed this interaction using solution 19F and 2D ¹⁵N–¹H HSQC NMR spectroscopy and studied the aggregation properties of these two proteins. Here, we show that α-syn interacts with S100A9 at specific regions, which are also essential in the first step of aggregation. We also demonstrate that the 4-fluorophenylalanine label in alpha-synuclein is a sensitive probe to study interaction and aggregation using 19F NMR spectroscopy.