Materials Literature
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The ultraviolet (uv) absorption spectra, representing transitions to all energy levels below 44 500 cm−1 of trivalent erbium (Er3+), have been analyzed for the crystal-field splitting of the multiplet manifolds L2S+1J of Er3+(4f11) in C2 symmetry cation sites in single-crystal cubic Er2O3 and Er3+:Y2O3. A solid soluti…
We suggest a method for the a priori determination of the electrical percolation threshold in carbon nanotube (CNT) networks, of relevance in electronic devices, polymer composites, etc. The variability in the CNT lengths, commonly observed in practical processing and dispersion, was also considered and the resulting…
Gallium-doped zinc oxide thin films were prepared on glass substrates by dc magnetron sputtering under various hydrogen contents in sputtering ambient. The carrier concentration of the films deposited at low-temperatures (80 and 160 °C) was increased due to the incorporation of hydrogen atoms, acting as shallow donors…
Graphene was epitaxially grown on a 6H-SiC(0001) substrate by thermal decomposition of SiC under ultrahigh vacuum conditions. Using scanning tunneling microscopy (STM), we monitored the evolution of the graphene growth as a function of the temperature. We found that the evaporation of Si occurred dominantly from the c…
We report the iron (Fe) isotope effect on the transition temperature (${T}_{c}$) in oxygen-deficient ${\mathrm{SmFeAsO}}_{1\ensuremath{-}y}$, a 50-K-class, Fe-based superconductor. For the optimally doped samples with ${T}_{c}=54\text{ }\text{ }\mathrm{K}$, a change of the average atomic mass of Fe (${M}_{\mathrm{Fe}}…
Abstract Linear isocyanate‐terminated poly(urethane‐imide) (PUI) with combination of the advantages of polyurethane and polyimide was directly synthesized by the reaction between polyurethane prepolymer and pyromellitic dianhydride (PMDA). Then octaaminophenyl polyhedral oligomeric silsesquioxane (OapPOSS) and PUI wer…
Abstract The Raman spectra of a series of related minerals of the pinakiolité group have been collected and the spectra related to the mineral structure. These minerals are based upon an isolated BO33− ion. The site symmetry is reduced from D3h to C1. Intense Raman bands are observed for the minerals takeuchiité, pina…
Abstract In the present contribution, the ultrafine fiber membranes of polyhydroxybutyrate (PHB) and organic‐soluble chitosan(O‐CS) was prepared by electrospinning. The structure and thermal stability were studied by infrared (FTIR) and thermogravimetric analysis (TG). The surface properties of ultrafine fibers were e…
Phase diagrams of electron- and hole-doped ${\text{SrFe}}_{2}{\text{As}}_{2}$ single crystals are investigated using Co and Mn substitution at the Fe sites. We find that the spin-density-wave state is suppressed by both dopants but the superconducting phase appears only for Co (electron) doping, not for Mn (hole) dopi…
Abstract The aim of this work is to characterize the rheological and permeability behavior of nanocomposites based on amorphous poly(ethylene terephthalate) (PETg) and organically modified montmorillonites (omMMT), obtained by melt intercalation. The use of PETg instead of semicrystalline PET is believed to reduce the…
We present a semiempirical model based on the shadowing effect to describe quantitatively the aggregation of columnar structure during physical vapor condensation onto a surface with an array of line seeds and a flat surface. Specifically, we predict the relationship between the column angle and the incident flux angl…
We study the smectic director structure of the rodlike liquid crystal 4-n-dodecyl-4'-cyanobiphenyl (12CB) confined in cylindrical cavities of 200 nm diameter in porous alumina templates by means of combined broadband dielectric spectroscopy, optical birefringence, and neutron scattering measurements. We show that the…
Abstract A new family of positively charged, water soluble and functional amino acid‐based poly(ester amide)s (Arg‐AG PEA) consisting of four building blocks (L‐Arginine, DL‐2‐Allylglycine, oligoethylene glycol, and aliphatic diacid) were synthesized by the solution copolycondensation. Functional pendant carbon–carbon…
A maskless method of employing polymer growth inhibitor layers is used to modulate the conflicting parameters of density and alignment of multi-junction nanowires via large-scale low temperature chemical route. This low temperature chemical route is shown to synthesize multi-junction nanostructures without compromisin…
The luminescent properties of the Ce3+ or Dy3+ singly doped and Ce3+/Dy3+ codoped in Ca3Y2Si3O12 novel phosphors were investigated, which are prepared by a sol-gel method. Ce3+ doped phosphor showed a brighter and broader violet-blue color emission band with a maximum peak centered at 389 nm, which is attributed to th…
A kinetic study for the electrosynthesis of polypyrrole (Ppy) doped with SO(4)(2-) ions is presented. Ppy films were electrochemically polymerized onto a graphite-epoxy resin electrode. Experimental current density transients (j-t) were obtained for three different potentiometric behaviors: anionic, cationic, and a co…
Lignocellulosic biomass offers economic and environmental advantages over corn starch for biofuels production. However, its fractionation currently requires energy-intensive pretreatments, due to the lignin chemical resistance and complex cell wall structure. Recently, ionic liquids have been used to dissolve biomass…
The factors influencing the crystalline structure of polymorphic polymer have been investigated for random copolyester, poly(hexamethylene adipate- co -butylene adipate) (P(HA- co -BA)). P(HA- co -BA) exhibits isodimorphic crystallization. The crystalline modification of the PBA homopolymer type crystal was regulated…
A study has been carried out to evaluate physical and flexural properties of composites made by areca fibers with a randomly distributed orientation of fibers. The extracted areca fibers from the areca husk were alkali treated with potassium hydroxide (KOH) to get better interfacial bonding between fiber and matrix. T…
We investigate the dynamics of colloids at a fluid interface driven by attractive capillary interactions. At submillimeter length scales, the capillary attraction is formally analogous to two-dimensional gravity. In particular it is a nonintegrable interaction and it can be actually relevant for collective phenomena i…