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991.
992.
Lin Q Wu T Zheng ST Bu X Feng P 《Chemical communications (Cambridge, England)》2011,47(43):11852-11854
Reported here is a rare example of a highly symmetrical chiral Mg-based MOF (CPF-1) with nanotubular channels, built from 4(1) (or 4(3)) helical chains. It exhibits a high gas sorption capacity (ca. 1.29 wt% H(2) at 77 K, 1 atm; 84 cm(3) g(-1) of CO(2) at 273 K, 1 atm). 相似文献
993.
Xu CJ Li BG Wan JT Bu ZY 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2011,82(1):159-163
A polymerizable ligand, 5-acrylamido-1,10-phenanthroline (L), was synthesized. Its Eu(III) complex with 2-thenoyltrifluoroacetone (HTTA) was prepared and characterized by elemental analysis, IR, MS, and 1H NMR spectra. The photophysical properties of the complex were studied in detail by using UV, luminescence spectra, luminescence lifetime and quantum yield. The complex shows a remarkable luminescence quantum yield at room temperature (40.1%) upon ligand excitation and a long 5D0 lifetime (590 μs), which makes it not only a promising light-conversion molecular device but also an excellent luminescent polymer precursor. 相似文献
994.
The ring‐opening polymerization of propylene oxide catalyzed by double metal complex (DMC) is carried out in continuous micro‐reactor (C‐MR). It is found that the monomer conversion at the C‐MR outlet is usually 100% within 2 min of average residence time, which means that the polymerization rate in the C‐MR is faster than that in a traditional semi‐continuous tank reactor. However, the induction period still exists in the polymerization in C‐MR, but can be shortened by increasing the reaction temperature or the micro‐reactor length. The mechanism of monomer coordination and ring opening on DMC during the induction period is confirmed by the 1H NMR analysis of the samples obtained under very short average residence time. The molecular weight distribution (MWD) of product from C‐MR is generally narrow, which indicates that the process still maintain the characteristics of the “living” polymerization. That is, there is a very high rate ratio of chain transfer to chain propagation provided by the DMC catalyst. However, with the same average residence time, the MWD of product from the longer C‐MR is broader, which can be attributed to the increase of the chain propagation rate caused by rise of pressure. 相似文献
995.
采用一步水热合成法制得花球状Bi_2WO_6和Ag/Bi_2WO_6光催化剂,借助X射线衍射(XRD)、场发射扫描电子显微镜(FES-EM)、透射电子显微镜(TEM)、X射线光电子能谱分析(XPS)、紫外-可见分光光度法(UV-Vis)等手段对样品进行结构性能表征。模拟日光的条件下,以甲基橙(MO)为降解物,对Bi_2WO_6和Ag/Bi_2WO_6的催化活性和机理进行研究。结果表明,相对Bi_2WO_6,相同条件下Ag/Bi_2WO_6对MO具有更佳的降解效果,当Ag掺杂量为1%(n/n)时,其降解率(180 min)可达到91.4%,同时一次回收样降解率也达到81%。此外,也对Ag/Bi_2WO_6复合材料的降解机理做了初步探究。 相似文献
996.
The graphene nanopowder for electro-catalytic oxidation of dopamine and uric acid in the presence of ascorbic acid has been investigated by cyclic voltammetry,linear polarization and chronoamperometry.The graphene nanopowder modified electrode was prepared using the drop coating method,which displayed excellent electrocatalytic activity towards the oxidation of dopamine and uric acid compared with the bare glassy carbon electrode in phosphate buffer solution at pH=7.0.Linear responses for dopamine and uric acid were obtained in the ranges of3.3μmol/L to 249.1μmol/L and 6.7μmol/L to 386.3μmol/L with detection limits of 1.5μmol/L and 2.7μmol/L(S/N=3),respectively.The response time was less than 2 s in case of dopamine and 3 s in case of uric acid,respectively.The results demonstrated that the graphene nanopowder had potential for detecting dopamine and uric acid. 相似文献
997.
R. Lach M. M. Bućko K. Haberko M. Szumera R. Gajerski 《Journal of Thermal Analysis and Calorimetry》2013,112(2):727-730
Co-precipitation of alumina/YAG precursor from aluminum and yttrium nitrates solution with ammonium carbonate results in dawsonite (NH4Al(OH)2CO3). Its crystallographic parameters differ from the compound precipitated without the yttrium additive. It indicates that yttrium ions become incorporated into the dawsonite structure. The DSC/TG and X-ray measurements show decomposition of dawsonite at elevated temperature resulting in γ-Al2O3 which transforms to δ and θ modifications at still higher temperatures. The full transformation to α-Al2O3 and YAG occurs at temperatures higher than 1,230 °C. 相似文献
998.
Lablanquie P Penent F Palaudoux J Andric L Selles P Carniato S Bučar K Zitnik M Huttula M Eland JH Shigemasa E Soejima K Hikosaka Y Suzuki IH Nakano M Ito K 《Physical review letters》2011,106(6):063003
The formation of hollow molecules (with a completely empty K shell in one constituent atom) through single-photon core double ionization has been demonstrated using a sensitive magnetic bottle experimental technique combined with synchrotron radiation. Detailed properties are presented such as the spectroscopy, formation, and decay dynamics of the N(2)(2+) K(-2) main and satellite states and the strong chemical shifts of double K holes on an oxygen atom in CO, CO2, and O2 molecules. 相似文献
999.
In this paper, we introduce a new implicit iterative algorithm for finding a common element of a countable family of continuous pseudocontractions in a uniformly smooth Banach space. We obtain some strong convergence theorems under suitable conditions. Our results extend the recent results announced by many others. 相似文献
1000.