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961.
Sungkoo Lee Sangmyung Lim Eunhee Lim Kyeong K. Lee 《Journal of Physics and Chemistry of Solids》2010,71(4):483-9829
Graphene sheets were produced by chemical reduction of graphite oxides in the solution of ionic conductive polymer, Nafion. The obtained graphene, coated with Nafion, can be re-dispersed in water, and readily forms stable dispersed state. The polymer-coated graphene had been characterized by FT-IR spectroscopy, UV-vis and X-ray photoelectron spectroscopy (XPS). The PEDOT film with Nafion-coated graphene increased significantly from 0.25 S/cm for pure PEDOT film and reached 12 S/cm. Further, the films of PEDOT doped Nafion-coated graphene had also higher conductivities compared to films doped PSS-coated graphene. 相似文献
962.
Plasma Treatment Enhanced Magnetic Properties in Manganese Doped Titanium Nitride Thin Films
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The ferromagnetic manganese doped TiN films were grown by plasma assisted molecular beam epitaxy on MgO(001) substrates. The nitrogen concentration and the ratio of manganese at Ti lattice sites increase after the plasma annealing post treatment. TiN(002) peak shifts toward low angle direction and TiN(111) peak disappears after the post treatment. The lattice expansion and peak shift are mainly ascribed to the reduction of nitrogen vacancies in films. The magnetism was suppressed in as-prepared sample due to the pinning effect of the nitrogen vacancies at defect sites or interface. The magnetism can be activated by the plasma implantation along with nitrogen vacancies reduce. The decrease of nitrogen vacancies leads to the enhancement of ferromagnetism. 相似文献
963.
A method is described for the quantification of the sp2, sp3 and intermediate hybridizations in several carbon (C) material samples. Electron energy-loss near-edge spectra were acquired using fast electrons (120 keV) in an electron microscope in nanobeam configuration under the so-called ”magic-angle” condition, and were analysed to extract the sp2 and sp3 fractions, and identify the possible mixed sp2+ε hybridizations. The method consists in projecting the unknown spectra on a basis made up of pure sp2 and sp3 spectra, obtained under the same experimental conditions from graphite and diamond crystals, respectively. The residual spectra contain information about the intermediate hybridizations sp2+ε occurring in the samples. The method was successfully tested on “ab initio” numerically generated spectra relative to amorphous C materials. Finally, it was applied to actual C amorphous and pyrolytic samples, and results were compared to those obtained by the most commonly used, conventional ”three-Gaussian” method. The combined application of electron diffraction and spectroscopy, in the nanobeam configuration, yielded useful information about the atomic and electronic structure from very small volumes of the unknown C material. 相似文献
964.
Dr. Todd R. Zeitler Timothy Van Heest Prof. David S. Sholl Dr. Mark D. Allendorf Dr. Jeffery A. Greathouse 《Chemphyschem》2013,14(16):3740-3750
A set of 98 nanoporous framework material (NFM) structures was investigated by classical Grand canonical Monte Carlo simulations for low-pressure O2 adsorption properties (Henry’s constant and isosteric heat of adsorption). The set of materials includes those that have shown high O2 uptake experimentally as well as a subset of more than 2000 structures previously screened for noble-gas uptake. While use of the general force field UFF is fruitful for noble-gas adsorption studies, its use is shown to be limited for the case of O2 adsorption—one distinct limitation is a lack of sufficient O2–metal interactions to be able to describe O2 interaction with open metal sites. Nonetheless, those structures without open metal sites that have very small pores (<2.5 Å) show increased O2/N2 selectivity. Additionally, O2/N2 mixture simulations show that in some cases, H2O or N2 can hinder O2 uptake for NFMs with small pores due to competitive adsorption. 相似文献
965.
Cucurbituril‐mediated immobilization of fluorescent proteins on supramolecular biomaterials
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Olga J. G. M. Goor Ralph P. G. Bosmans Luc Brunsveld Patricia Y. W. Dankers 《Journal of polymer science. Part A, Polymer chemistry》2017,55(21):3607-3616
The reversible introduction of functionality at material surfaces is of interest for the development of functional biomaterials. In particular, the use of supramolecular immobilization strategies facilitates mild reaction and processing conditions, as compared to other covalent analogues. Here, the engineering of multicomponent supramolecular materials, beyond the use of a single supramolecular entity is proposed. Cucurbit[8]uril (Q8) mediated host–guest chemistry is combined with hydrogen bonding supramolecular 2‐ureido‐4‐pyrimidinone (UPy)‐based materials. The modular incorporation of a UPy‐additive that presents one guest to incorporate into the Q8 host allows for selective supramolecular functionalization at the water–polymer material interface. Supramolecular ternary complex formation at the material surface was studied by X‐ray photoelectron spectroscopy, which as a result of large overlap in atomic composition of the different components showed minor changes is surface composition upon complex formation. Surface MALDI‐ToF MS measurements revealed useful insights in the formation of complexes. Protein immobilization was monitored using both fluorescence spectroscopy and quartz crystal microbalance with dissipation monitoring, which successfully demonstrated ternary complex formation. Although proteins could selectively be immobilized onto the surfaces, control of the system's stability remains a challenge as a result of the dynamicity of the host–guest assembly. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 3607–3616 相似文献
966.
In this work, we report the magnetic properties of isotropic M-type SrFe12−xAlxO19 (x=0.0,1.5) hexaferrites synthesized by means of Pechini method. A polycrystalline distribution of fine grains was verified by Transmission Electron Microscopy for both compositions, with average sizes below 60 nm. Remarkable coercivity values within the range 500–850 kA/m were attained as a consequence of a combined effect of grain size refinement together with an enhancement of the anisotropy field afforded by the incorporation of the Al3+ cations into the hexagonal crystal structure. 相似文献
967.
968.
ZHANG ZhaoXiang ZHANG XiaoWei & LI Feng Key Laboratory of Eco-Chemical Engineering Ministry of Education College of Chemistry Molecular Engineering Qingdao University of Science Technology Qingdao China School of Science Qingdao Technological University Qingdao China 《中国科学:化学》2010,(5)
A novel method has been developed by integration of multi-concentration and two-dimensional(2D) capillary electrophoresis(CE) for simultaneous enhancement of detection sensitivity and separation power in complex samples.Capillary zone electrophoresis(CZE) was used as the first dimension separation according to mobilities,from which the effluent fractions were further analyzed by micellar electrokinetic capillary chromatography(MEKC) acting as the second dimension.Cation-selective exhaustive injection(CSEI) ... 相似文献
969.
BaGd2O4, BaLa2O4 and SrLa2O4 powders doped with different concentrations of Eu3+ or Tb3+ are prepared by combustion synthesis method and the samples were further heated to 500, 700 and 900 °C to improve the crystallinity of the materials. The structure and morphology of materials have been examined by X-ray diffraction and scanning electron microscopy. It is remarkable that all the samples of BaGd2O4, BaLa2O4 and SrLa2O4 have similar morphology. The SEM images show homogeneous aggregates of varying shapes and sizes, which are composed of a large number of small elliptical shaped crystallites with an average diameter of about 0.5-3.0 μm. Photoluminescence for all materials increases with increase of temperature and shows a maximum for the samples heated to 900 °C with 4 mole% doping of Eu3+ or Tb3+ ions. The luminescence is almost same for all powders when doped with same concentration of Eu3+. 相似文献
970.