Materials Literature
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Abstract Mesoporous silica and carbon with high surface area and large pore size were readily prepared in a dilute silica solution at pH ≈4.0–6.0 by using the biodegradable gelatin or gelatin–phenol–formaldehyde polymer blend as template.
The influence of the chemical composition on structural properties and electrical conductivity of solid solutions based on the system Y−Ce−ZrO 2 obtained by the hydroxide precipitation method is investigated. The samples are studied by combining impedance spectroscopy, X-ray powder diffraction, and scanning electron m…
We have observed bright photoluminescence (PL) from single-walled carbon nanotubes (SWNTs) on self-assembly monolayer (SAM) functionized SiO 2 /Si substrates. By contrast, no PL was observed from pristine SWNTs grown on substrates (SiO 2 /Si and Al 2 O 3 ). This suggests a successful blocking of substrate-induced nonr…
Optical absorption, photoluminescence, and Raman scattering spectra of poly(para-phenylene vinylene) (PPV) and single-walled carbon nanotube (SWNT) composite films are investigated at room temperature. Samples have been prepared at different precursor conversion temperatures, T c, (300, 180,and 120 °C) and with SWNT m…
Zero field and longitudinal field muon-spin relaxation measurements were carried out for the single-chain magnet catena -[Fe II (ClO 4 ) 2 {Fe III (bpca) 2 }]ClO 4, to reveal the growth of short-range spin ordering in the zero-external magnetic field below 6 K.
Single-crystalline Zn 1- x Mn x O ( x = 0.05, 0.1, and 0.2) nanowires were synthesized using the thermal vapor transport method. Their X-ray diffraction patterns reveal the monotonous expansion of the lattice constants with increasing Mn content, due to the effective Mn doping. The electronic structures of the Zn and…
Reports on PZT films often suggest the contradicting presence of Pb‐deficient pyrochlore (Py) and a Pb‐rich layer on the surface. We show that standard Ar + ion sputtering X‐ray photoelectron spectroscopy (XPS) depth profiles of PZT films artificially exhibit a Pb‐rich surface, independent of actual Pb content of the…
Vapor-phase synthesis of 2-methylpyrazine (2-MP), from propylene glycol (PG) and ethylenediamine (ED), has been studied over ferrite catalysts in a temperature range of 523−773 K. The performance of MnFe 2 O 4 was observed to be better than that of Zn 1 - x Mn x Fe 2 O 4 ( x = 0, 0.25, 0.5, 0.75). The reaction was det…
Complex materials as fuel oils are characterized by physical and chemical parameters. This paper deals with the determination of the activation energy of three kinds of Brazilian fuel oils. As it is possible to establish a direct relation between ignition delay and activation energy, these kinetic parameters can be us…
The dielectric and piezoelectric properties of SrBi 2− x Sm x Nb 2 O 9 ( x =0, 0.05, 0.1, 0.2, 0.3, and 0.4) ceramics were investigated. SrBi 2− x Sm x Nb 2 O 9 ceramics were synthesized by the conventional solid‐state reaction sintering method. An X‐ray diffraction measurement indicated that a single‐phase‐layered pe…
An acid recrystallization process for synthesis of ultrafine TATB (UF-TATB) of median particle size < 5 µm is described. The process uses production grade TATB (PG-TATB) of median particle size > 50 µm. PG-TATB is made soluble in DMSO-alkali. Acidification of this basic solution is done with dilute aqueous nitric acid…
High Resolution Image Download MS PowerPoint Slide Physical and chemical properties of single-walled carbon nanotubes (SWCNTs) are sensitive to the defects in the tubular graphene. To date, however, the method to characterize the defect of SWCNTs has been limited to transmission electron microscopy (TEM) and atomic fo…
The homoleptic diamagnetic complexes M(mer-L)(2), M = Cr, Mo,W (1a,b, 2a,b, and 4a,b), were obtained by reacting the hexacarbonyls M(CO)(6) with the tridentate ligands 2-[(2-N-arylamino)phenylazo]pyridine (HL = NH(4)C(5)N=NC(6)H(4)N(H)C(6)H(4)(H) (HL(a)) or NH(4)C(5)N=NC(6)H(4)N(H)C(6)H(4)(CH(3)) (HL(b))) in refluxing…
A feasible doping strategy is introduced to synthesize Eu 2+ ‐doped α‐Si 3 N 4 nanowires coated with a thin BN film. The nanowires were characterized by X‐ray diffraction, scanning electron microscopy, high‐resolution transmission electron microscopy, and a fluorescence spectrophotometer. The Eu 2+ ‐doped α‐Si 3 N 4 n…
Physico‐chemical equilibria that influence oxide powders' precipitation from an aqueous solution can be substantially altered when the process is carried out in a microemulsion system. To obtain nanosized MnFe 2 O 4 and gain information about the physico‐chemical characteristics of products, Mn 2+ and Fe 3+ metal ions…
Interaction of the dilacunary polyanion precursor [gamma-GeW(10)O(36)](8-) with Fe(3+) ions in aqueous buffer medium (pH 4.8) results in the formation of two dimeric tungstogermanates depending on the reactant ratios. When using an Fe3+ to [gamma-GeW(10)O(36)](8-) ratio of 1:1, the asymmetric anion [K(H(2)O)(beta-Fe(2…
Hydrolytically degradable polyamines can be used to fabricate multilayered polyelectrolyte films that erode and release DNA in aqueous environments. Past studies have investigated films fabricated from poly(beta-amino ester) 1 and the influence of polymer backbone structure on film erosion and the release of anionic p…
Stimulus-responsive, or "smart" protein-based hydrogels are of interest for many bioengineering applications, but have yet to include biological activity independent of structural functionality. We have genetically engineered bifunctional building blocks incorporating fluorescent proteins that self-assemble into robus…
Zinc oxide nanocrystals (ZnO NCs) prepared in rigorously oxygen-free conditions do not emit in the visible until they are exposed to oxygen. A spectrophotometric O 2 titration of oxygen-free ZnO NC allows for the determination of the stoichiometry, kinetics, and luminescent properties of this critical interaction, bes…
Bipolar cycling of lead zirconate titanate ceramics can lead to massive material damage in regions close to the electrode. The damaged region can be identified by color changes, and the microstructure in this region shows signs of interface melting. This damaged region can screen the sample volume from the applied vol…