Mesoporous siliceous particles were prepared using deep eutectic solvents (DESs)—either choline chloride and 1,2-butanediol in a 1:2 molar ratio (ChCl-B) or choline chloride and glycerol in a 1:2 molar ratio (ChCl-G)—and then tested as column packing materials in size-exclusion chromatography (SEC). When they were tested as column packing materials in SEC of a mixture of two dextrans with different molecular weights using a methanol mobile phase, the ChCl-G-based particles were not able to separate the dextrans, whereas the ChCl-B-based particles provided good separation (considerably better than that afforded by traditional sorbents) at a flow rate of 0.3 mL min−1. This high separating power of the ChCl-B-based particles can be attributed to the utilization of the DES ChCl-B during their preparation.
A series of eleven heteroleptic bis(phthalocyaninato) rare earth double‐deckers [MIII(pc){pc(α‐OC5H11)4}] 1 – 11 (M=Y, Sm? Lu; pc=phthalocyaninato; pc(α‐OC5H11)4=1,8,15,22‐tetrakis(1‐ethylpropoxy)phthalocyaninato) were prepared as racemic mixtures by [MIII(pc)(acac)]‐induced (acac=acetylacetonato) cyclic tetramerization of 3‐(1‐ethylpropoxy)phthalonitrile in the presence of 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU) in refluxing pentanol. These compounds could also be prepared by treating [MIII(pc)(acac)] with the metal‐free phthalocyanine H2{pc(α‐OC5H11)4} in refluxing octanol. The whole series of double‐decker complexes 1 – 11 were characterized by elemental analysis and various spectroscopic methods. The molecular structures of the Sm, Eu, and Er complexes 1, 2 , and 8 , respectively, were also determined by single‐crystal X‐ray diffraction analysis. The effects of the rare earth ion size on the reaction yield, molecular structure, and spectroscopic and electrochemical properties of these complexes were systematically examined. 相似文献
A study on heat transfer during thermoplastic composite tape lay-up process was done. To investigate the relation between major process variables, experiments as well as numerical simulations were performed. A small-scale tape lay-up system was built. A hot nitrogen torch was used to heat the prepreg tape. Right after the torch, a compaction roller was located to bond the prepreg plies. Temperatures inside the composite at four different locations through the thickness were measured, using thermocouples. Experiments were done for different process conditions. Numerical simulations also were performed, using the finite element code developed in this study. A numerical code was run for the same conditions as the experiment. Close agreement was observed between the numerical results and the experimental data. 相似文献
The NingQiang carbonaceous meteorites from the Shan Xi(China) was falling in 1983. In this report, the Mössbauer spectra has been measured for the NingQiang meteorites and the spectra were analysed with computer. The experimental results indentify it as a carbonaceous meteorite of type III. The spectrum shows the principal iron components to be of olivine, magnetite, troilite and phyllosilicate or goethite material. For comparation the Mössbauer spectra of the Allende and Leoville carbonaceous meteorites have been also measured. 相似文献
We study the twisted Alexander invariants of fibred knots. We establish necessary conditions on the twisted Alexander invariants for a knot to be fibred, and develop a practical method to compute the twisted Alexander invariants from the homotopy type of a monodromy. It is illustrated that the twisted Alexander invariants carry more information on fibredness than the classical Alexander invariants, even for knots with trivial Alexander polynomials.
Copper cluster anions in the size range of 1-18 atoms are studied by photoelectron spectroscopy. Using photons of 5.0 eV energy the electronic level structure built from the delocalized s-orbitals of the atoms is revealed. An attempt is made to assign the observed bands to the electronic shells predicted by the jellium model. Even though the general behavior resembles the predictions of this model, the spectra are much more complicated reflecting the discrete atomic geometry of these particles. 相似文献