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A bicontrollable drug release system was developed by layer-by-layer assembly of poly(allylamine hydrochloride) (PAH)/sodium poly(styrene sulfonate) (PSS) multilayers onto a Fe3O4/SiO2 composite core. The saturated magnetization of this system reaches up to 38.6 emu/g at RT, making targeting easily controlled by an external magnetic field. Meanwhile, the packing of the polyelectrolyte multilayers is sensitive to pH values, generating a pH-switch on-off mode for the release of loaded drugs. In this specific case, the release of a chemotherapeutic polyoxometalate K7Ti2W10PO40·6H2O (PM–19) was tested. Transmission electron microscopy (TEM) was used to examine the nanostructure of the composite drug release system. UV–vis absorption was used to monitor the drug release. Fourier transform infrared (FTIR), Powder X–ray diffraction, and Elemental analyses were used to study the composition of tested systems. The structure and composition of the composite system was also studied using magnetism measurement and nitrogen adsorption–desorption. 相似文献
966.
Shou-Nian Ding Serge Cosnier Dan Shan Yue-Ming Sun Yao Wang 《Electrochemistry communications》2010,12(7):905-908
Elelctrogenerated chemiluminescence (ECL) of electropolymerized films based on [(2,2′-bipyridyl)(4-(2-pyrrol-1-ylethyl)-4′-methyl-2,2′-bipyridyl)2]ruthenium (II) was firstly investigated in both organic and aqueous solution. The ECL behaviors have been explained by two typical mechanisms, namely, redox-cycling type and oxidative-reduction type. For the former, no co-reactant was required and for the latter, tripropylamine (TPA) and (NH4)2C2O4 were selected as co-reactants in the organic and aqueous system, respectively. 相似文献
967.
The electrochemical properties of La0.8Sr0.2FeO3???δ (LSF)–La0.45Ce0.55O2???δ (LDC) composite cathodes coated on LSGM electrolyte were studied by electrochemical impedance spectroscopy and cathodic polarization technique. Results showed that the composite cathodes possessed superior electrochemical performance compared to that of pure LSF cathode. The cathodic overpotential of Cathode C was only 100 mV at 0.3 A cm?2, and the charge transfer resistance and the gas phase diffusion resistance were decreased to 0.105 Ω cm2 and 0.257 Ω cm2, respectively at 800 °C. The improvement of the electrochemical performance is contributed to the increase of the triple-phase boundary, enlargement of the effective area for electrode reaction, and increase of the porosity of the cathode by adding LDC to the cathode material. 相似文献
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The period interaction on diffraction of the blazed transmission gratings is analyzed with a modified extended scalar theory. For one certain period, the lights reflected from the neighboring structures can be refracted by the grating facets and form two extra fields on the bottom facet of blazed transmission gratings. The effects of this period interaction versus several diffraction orders for a fixed fabrication error of blazed transmission gratings with intermediate structures are discussed for both TE and TM polarizations. The results have been compared with those obtained with finite-difference time-domain method. 相似文献