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41.
The photoluminescence of Co-Al-layered double hydroxide 总被引:1,自引:0,他引:1
Shuai Sun Wan Guo Hou 《中国化学快报》2007,18(11):1371-1373
We report a new optical behaviour of pure Co-Al-layered double hydroxide (LDH).It was found that the Co-Al-LDH sample could emit fluorescence without any fluorescent substances intercalated.Its excitation spectrum shows a maximum peak near the wavelength 370nm,the maximum emission peak appears at 430 nm and the photoluminescence colour of the Co-Al-LDH sample is blue.This new optical property will be expected to extend the potential applications of LDHs in optical materials field. 相似文献
42.
Using potentially bidentate ligands (-SC2H4NH2), we produced [2Fe-2S]+ species of different coordination geometries by fission of [4Fe-4S]2+ complexes. Even though the ligands are monodentate in the cubane complexes, both mono- and bidentate complexes were observed in the [2Fe] fission products through self-assembly because of the high reactivity of the tricoordinate iron sites. The electronic structure of the [2Fe] species was probed using photoelectron spectroscopy and density functional calculations. It was found that tetracoordination significantly decreases the electron binding energies of the [2Fe] complexes, thus increasing the reducing capability of the [2Fe-2S]+ clusters. 相似文献
43.
The enthalpy change of formation of the reaction of hydrous dysprosium chloride with ammonium pyrrolidinedithiocarbamate (APDC) and 1,10-phenanthroline (o-phen?H2O) in absolute ethanol at 298.15 K has been determined as (-16.12 ± 0.05) kJ?mol-1 by a microcalormeter. Thermodynamic parameters (the activation enthalpy, the activation entropy and the activation free energy), rate constant and kinetics parameters (the apparent activation energy, the pre-exponential constant and the reaction order) of the reaction have also been calculated. The enthalpy change of the solid-phase reaction at 298.15 K has been obtained as (53.59 ± 0.29) kJ?molt-1 by a thermochemistry cycle. The values of the enthalpy change of formation both in liquid-phase and solid-phase reaction indicated that the complex could only be synthesized in liquid-phase reaction. 相似文献
44.
45.
Wenxuan Jiang Wei Wei Tinglian Yuan Shasha Liu Ben Niu Hui Wang Wei Wang 《Chemical science》2021,12(24):8556
The inevitable microstructural defects, including cracks, grain boundaries and cavities, make a portion of the material inaccessible to electrons and ions, becoming the incentives for electrochemically inactive zones in single entity. Herein, we introduced dark field microscopy to study the variation of scattering spectrum and optical mass centroid (OMC) of single Prussian blue nanoparticles during electrochemical reaction. The “dark zone” embedded in a single electroactive nanoparticle resulted in the incomplete reaction, and consequently led to the misalignment of OMC for different electrochemical intermediate states. We further revealed the dark zones such as lattice defects in the same entity, which were externally manifested as the fixed pathway for OMC for the migration of potassium ions. This method opens up enormous potentiality to optically access the heterogeneous intraparticle dark zones, with implications for evaluating the crystallinity and electrochemical recyclability of single electroactive nano-objects.The schematic of single cubic-shaped Prussian blue (PB) mesocrystals formed by the oriented aggregation of small nanocrystals. The dark-field images of single PB nanoparticle at PB and Prussian white (PW) states, respectively. 相似文献
46.
Zhenbin Niu Xingyuan Zhang Jiabing Dai Heping Zhang 《Frontiers of Chemistry in China》2007,2(2):151-155
A new kind of ultraviolet (UV) curable waterborne polyurethane acrylate dispersion was synthesized based on hydroxyl-terminated
polybutadiene (HTPB), poly-(propylene glycol) (PPG), isophorene diisocyanate (IPDI), 2-hydroxy ethyl acrylate (HEA) and dimethylol
propionic acid (DMPA) after neutralizing by triethylamine (TEA). 2-Hydroxy-1-[4-2-hydroxyethoxy) phenyl]-2-methyl-1-propanone
(Irgacure 2959) was used as a photoinitiator and deionized water as a diluent. Fourier transform infrared (FTIR) analysis
was used to identify the chain structure of the UV-curable polyurethane prepolymer based on HTPB and the curing process. Effects
of relative content of HTPB and PPG on emulsion stability, resistance to water and ethanol, thermal stability, compatibility
of soft and hard segment, as well as the mechanical property of the cured film were investigated.
Translated from Polymer Materials Science and Engineering, 2006, 22(3): 199–203 (in Chinese) 相似文献
47.
Ying WANG Su Juan WANG Shun Yan MO Shuai LI Yong Chun YANG Jian Gong SHI Institute of Materia Medica Chinese Academy of Medical Sciences Peking Union Medical College 《中国化学快报》2006,(4)
A new abietane diterpene 12-hydroxy-7-oxo-5, 8, 11, 13-tetraene-18, 6-abietanolide, together with a new natural sterol stigmasta-7, 22-diene-3β, 5α, 6α-triol have been isolated from the fruiting body of the fungus Phellinus igniarius. Their structures were elucidated by spectroscopic methods including 2D NMR techniques. 相似文献
48.
本文将用放射性磷32标记法测得的二(2-乙基己基)磷酸在碱金属氯化物水溶液(LiCl、NaCl、KCl、RbCl、CsCl和NH_4Cl)中的溶解度数据~[1], 分别用Pitzer(1973年)方程和Pitzer-Li(1983年)方程进行活度系数的关联. 计算结果表明, 由于Pitzer-Li方程考虑了溶质-溶剂间的短程作用能, 所得参数更能反映盐效应的本质, 故优于Pitzer方程. 同时还表明, 上述体系中离子-水之间的作用能远大于离子-有机化合物之间的作用能。 相似文献
49.
Yan-Ping Liu Li-Li Sun Xiang-Lin Zhang Hai-Yuan Niu Zheng-Hong Pan 《Natural product research》2020,34(16):2295-2300
Abstract A phytochemical investigation on the stems of Mappianthus iodoides led to the isolation of a new naturally occurring prenylated isoflavone, mappianthone A (1), together with seven known analogues (2?8). The structure of 1 was elucidated by extensive spectroscopic methods and the known compounds were identified by comparison with data reported in the literature. All isolated compounds were evaluated for their antiproliferative activities against five human cancer cell lines: HL-60, SMMC-7721, A-549, MCF-7 and SW480 in vitro. Compounds 1?8 showed significant antiproliferative effects against several human cancer cell lines with IC50 values ranging from 0.16 to 12.68?μM. 相似文献
50.
The fabrication and electrochemical characteristics of a penicillamine (PCA) self-assembled monolayer modified gold electrode were investigated. The self-assembled electrode shows obvious electrocatalytic activity for the oxidation of epinephrine (EP). In phosphate buffer (pH 7.73), a sensitive oxidation peak was observed at 0.190V with the PCA modified Au electrode. The peak current is proportional to the concentration of EP in the range of 2.0×10–56.0×10–4molL–1 and 5.0×10–6 2.0×10–4molL–1 for cyclic voltammetry (CV) and differential pulse voltammetry (DPV) with the detection limits of 1.8×10–7 and 1.3×10–7molL–1, respectively. The possible reaction mechanism is also discussed. The PCA self-assembled monolayer modified gold electrode is highly stable and can be applied to the determination of EP in practical injection samples. Application is simple, rapid and produces accurate results. 相似文献