A low temperature solvothermal method was employed to synthesize nitrogen-fluorine doped TiO2 materials (N/F -TiO2) at various mole ratio of Ti:F;10:1, 10:0.3 and 10:0.1, for photocatalytic applications. Doping fluori...
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Several approaches have been studied to prepare ionomers for a high temperature proton exchange membrane (PEM) fuel cell. These ionomers were designed to be very low equivalent weight (EW), chemically stable, solvent ...
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ISBN:
(纸本)9780841226319
Several approaches have been studied to prepare ionomers for a high temperature proton exchange membrane (PEM) fuel cell. These ionomers were designed to be very low equivalent weight (EW), chemically stable, solvent resistant and highly conductive. The synthetic approaches include grafting, hybrid formation and cross-linking. The most interesting results were obtained from cross-linking of functionalized PFSA ionomers with various cross-linking compounds. New side-chain component multifunctional ionomers have been developed that were cross-linkable during or after membrane fabrication. As a result of this approach, a suite of polymers have been synthesized that, after membrane casting and cross linking show improved solvent resistant, low swelling and excellent proton conductivity. An obvious approach to increase proton conductivity in PSFA materials is to lower the equivalent weight (EW) by increasing the number of protogenic groups. PFSA membranes with EW
We report results of the study of the low-frequency noise in thin films of bismuth selenide topological insulators, which were mechanically exfoliated from bulk crystals via "graphene-like" procedures. From ...
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The radiation-induced displacement damage in yttrium borate (YBO3) is studied under X-ray, proton, and alpha irradiation. The photoluminescence (PL) was tested before and after irradiation to determine whether damage ...
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The radiation-induced displacement damage in yttrium borate (YBO3) is studied under X-ray, proton, and alpha irradiation. The photoluminescence (PL) was tested before and after irradiation to determine whether damage occurred and whether it could be queried by examining the PL spectrum. Two different dopants (cerium and europium) were used to activate the phosphor because each provides not only a different spectral signature but also a different mechanism for altering the spectrum between the pre- and post-PL measurements. X-rays, being primarily ionizing radiation, did not show any significant change between the pre and post measurements. We expected protons and alphas to damage the crystal structure, evidence of which could be seen in the change in the spectra before and after irradiation. However, we found no change under alpha exposure (3.6 × 1010 particles/cm2) and a significant change after proton exposure (5 × 1015 particles/cm2). While the material appears to be sensitive to protons, we cannot rule out its sensitivity to alphas because the alpha fluence may be too low to show an effect. This result provides strong indication that our materials are being damaged by particle radiation and that the radiation effects can be quantified.
The influence of foam morphology on the release rate of Indomethacin (INM) from a solid solution prepared by hot melt extrusion was investigated. Closed cell foams were produced through a batch process, employing CO2 ...
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ISBN:
(纸本)9781622760831
The influence of foam morphology on the release rate of Indomethacin (INM) from a solid solution prepared by hot melt extrusion was investigated. Closed cell foams were produced through a batch process, employing CO2 as physical blowing agent. In all cases foamed disks showed faster INM's release than un-foamed disks. The time required for completing INM's release was reduced up to 75% mainly due to extensive and random breakage of the sample during dissolution test.
The perovskite SmFeO3 exhibits type-G antiferromagnetic ordering at TN ≈ 670 K and an easy axis rotation transition at TSR ≈ 480 K. Owing to the peculiar site anisotropy of rare-earth Sm3+, the moment on Sm3+ is ori...
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The perovskite SmFeO3 exhibits type-G antiferromagnetic ordering at TN ≈ 670 K and an easy axis rotation transition at TSR ≈ 480 K. Owing to the peculiar site anisotropy of rare-earth Sm3+, the moment on Sm3+ is oriented antiparallel to the canted spin from the Fe+ sublattice along the a axis at T < TSR. The development of the magnetic moment on Sm3+ as temperature decreases makes it possible to balance the two magnetic moments at Tcomp. The application of a moderate external magnetic field along the a axis can trigger an abrupt reversal of the moment on Sm3+ and the canted spin relative to the external field at a temperature around Tcomp. We report here a study of the field-induced magnetic-moment reversal in a single crystal SmFeO3 by measuring the magnetization and specific heat with the external field along different crystallographic axes.
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