Materials Literature
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Introduction A key feature of the chemistry of layered materials is the location of molecules (guests) of interest within the relatively constrained region of the interlayer. As such, the incorporation of guest molecules into layered hosts affords a versatile approach towards obtaining novel nanocomposite materials. O…
Abstract Isotactic polypropylene hollow fibers were produced by melt spinning. Spinning speeds up to 1880 m/min were used, and sample hollowness (percentage void in cross section) ranged from 0 to 69%. The fiber samples were characterized using dynamic mechanical analysis, birefringence, tensile testing, and different…
Abstract Polyimide hybrid films containing bimetalic compounds were obtained by codoping poly(amic acid) with a barium and titanium precursor prepared from BaCO 3 , Ti(OBu) 4 , and lactic acid followed by casting and thermal curing. FTIR, WAXD, and XPS measurements showed that barium and titanium precursor could be tr…
The diffusivity, permeability, and solubility coefficients of O 2, N 2, CO 2, and CH 4 have been measured in PVC and in four samples of PVC functionalized with mercapto pyridine groups up to 6.8, 11, 21, and 46 mol %. It has been found that the permeability of all four gases progressively increases by a factor of more…
ADVERTISEMENT RETURN TO ISSUECommunication to the...Communication to the EditorNEXTPhotochromic Dendrimers Containing Six AzobenzenesLi-Xin Liao, Denise M. Junge, and Dominic V. McGrathView Author Information Departments of Chemistry, University of Arizona, Tucson, Arizona 85721, and University of Connecticut, Storrs,…
We describe a model in which ${f(T)=M(T)/M}_{\mathrm{max}}$ represents both the fraction of the itinerant electron density in the double-exchange (DE) theory and the magnetization \ensuremath{\sigma} in the current carrier density collapse (CCDC) theory. With this model, we have checked the DE and CCDC theories with o…
We present a scheme to identify quasicrystals based on powder diffraction data and to provide a standardized indexing. We apply our scheme to a large catalog of powder diffraction patterns, including natural minerals, to look for new quasicrystals. Based on our tests, we have found promising candidates worthy of furth…
Good quality extended x-ray absorption fine structure (EXAFS) spectra near the Ga K edge have been collected in wide pressure and temperature ranges (namely 0--16 GPa, 298--498 K) using the dispersive setup installed at the LURE synchrotron radiation facility and diamond anvil cell as pressure device. Energy dispersiv…
We study x-ray absorption spectra below the O $1s$ threshold in Sc-doped stoichiometric strontium titanate $({\mathrm{SrTiO}}_{3}).$ We find hole states at the top of the valence band and acceptor-induced levels just above the Fermi level. The x-ray absorption spectra features and their temperature dependence are in g…
The cosubstituted solid solution In 2 - 2 x Sn x Zn x O 3 - δ was acceptor-doped with Zn 2+ to form In 2 - x - y Sn x Zn y O 3 - δ ( y > x ). A 4% Zn 2+ “excess” can be introduced in In 1.6 Sn 0.2 Zn 0.2 O 3 - δ while maintaining the bixbyite structure. The n-type conductivity of the doped material decreases with zinc…
The electrical conductivity, Hall effect, and thermoelectric coefficient of Zn/Sn-cosubstituted In 2 O 3 (In 2 - 2 x Sn x Zn x O 3 - δ ), undoped In 2 O 3, and indium−tin oxide (ITO) were studied vs cation composition, state of reduction, and measurement temperature (over the range of 4.2−340 K). Carrier contents and…
We report on magnetic susceptibility, magnetization, electric resistivity, and ESR experiments on single crystals of the covalent-chain antiferromagnetic compounds $\mathrm{TlFe}{X}_{2}$ $(X=\mathrm{S},$ Se). Collinear magnetic order with strongly reduced moments sets in at ${T}_{\mathrm{N}}=196 \mathrm{K}$ for ${\mat…
The molecular models of tubular aluminumsilicate, imogolite, and tubular gibbsite for the comparison with imogolite were investigated by means of molecular dynamics simulations. The stability of these two models was tested in terms of the tube radii. It was shown that the total energy of tubular gibbsite is decreasing…
The structure and electronic transport properties of hole-doped ${\mathrm{La}}_{3/4}{\mathrm{Ca}}_{1/4}{\mathrm{MnO}}_{3}$ perovskite have been investigated as a function of pressure up to about 15 GPa. Though the applied pressure enhances the electrical conductivity, the high-pressure resistivity data point out a com…
Abstract The formation of nanocomposites by the sol–gel reaction of tetraethoxysilane (TEOS) in polyacrylamide (PAAm) is studied. The nanocomposites are prepared in aqueous solution. Fourier transform IR spectroscopy shows that substantial hydrogen bonding occurs in the nanocomposites. The fracture surfaces of the nan…
Combined wide-angle X-ray diffraction (WAXD) and small-angle X-ray scattering (SAXS) studies using synchrotron radiation were carried out to investigate the structural development during in-situ solution spinning of poly( p -phenylenebenzobisoxazole) (PBO) in poly(phosphoric acid) (PPA). WAXD patterns indicated that t…
Abstract A new method for the synthesis of hyperbranched polymers involving the use of AB x macromonomers containing linear units have been investigated. Two types of novel hyperbranched polyurethanes have been synthesized by a one‐pot approach. The structures of monomers and polymers were characterized by elemental a…
A study has been made to investigate the radiation grafting of styrene onto poly(tetrafluoroethylene- co -perfluoropropylvinyl ether) (PFA) substrates, using the simultaneous irradiation method. Two PFA polymers of different comonomer perfluoropropyl vinyl ether (PPVE) content and degree of crystallinity were used. Ef…
We calculated the energy consumed for phase boundary motion in a ${\mathrm{Ni}}_{52}{\mathrm{Mn}}_{23}{\mathrm{Ga}}_{25}$ single-crystalline sample during martensitic transformation using a boundary friction phenomenological theory. It was found that the energy consumed for phase boundary motion is 13.14 J/mol, only a…
We investigate a system of one-dimensional Hubbard chains of interacting fermions coupled by interchain hopping. Using a generalization of the dynamical mean-field theory we study the deconfinement transition from a Mott insulator to a metal and the crossover between Luttinger and Fermi liquid phases. One-particle pro…