Materials Literature
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We present an optical study of the influence of both the flexoelectric effect and surface polarization on a hybrid-aligned nematic cell using the half-leaky guided mode technique. Tilt angle profiles, obtained from fits of experimental data (reflectivity curves) taken under applied voltages, are compared with the ones…
We have analyzed the experimental evidence of charge and orbital ordering in La0.5Sr1.5MnO4 using first principles band structure calculations. Our results suggest the presence of two types of Mn sites in the system. One of the Mn sites behaves as an Mn3+ ion, favoring a Jahn-Teller distortion of the surrounding oxyge…
Using an efficient numerical scheme that exploits spatial symmetries and spin parity, we have obtained the exact low-lying eigenstates of exchange Hamiltonians for the high-nuclearity spin clusters, ${\mathrm{Mn}}_{12},$ ${\mathrm{Fe}}_{8},$ and ${\mathrm{V}}_{15}.$ The largest calculation involves the ${\mathrm{Mn}}_…
The US Army Corps of Engineers CBR method (Method S77-1) for the design of flexible aircraft pavements was calibrated against full-scale trafficking tests on unbound pavements conducted 30 years ago. The method used single layer analysis so had no direct mechanism for crediting bound layers for their superior load spr…
Twelve samples of plastic materials employed in the industrial extraction of citrus essential oils were analyzed for the presence of phosphorated plasticizers, chloroparaffins, and phthalate esters. The samples tested were found to release these contaminants into the essential oils during the production process. Conta…
The effect of the large negative magnetoresistance in layered ferromagnetic metal ${\mathrm{GdI}}_{2}$ has been explained on the basis of the $s\ensuremath{-}f$ exchange model. Assuming the Ornstein-Zernike form of the spin-spin correlation function for the two-dimensional case, we calculate the resistivity in the vic…
Abstract A novel technique (pan‐milling mixing) was developed to control the morphology and thus enhance the mechanical properties of polypropylene/polyamide 6 (PP/PA6) systems. Through pan‐milling at ambient temperature, PP/PA6 pellets of particle size 2–4 mm can be effectively pulverized to well‐mixed micrometre fin…
Light-scattering spectra of two glasses, ${\mathrm{Ca}}_{0.4}{\mathrm{K}}_{0.6}({\mathrm{NO}}_{3}{)}_{1.4}$ and silica are measured in the frequency range $1--10000 \mathrm{GHz},$ covering temperatures from 19 K to 310 K. The low-frequency wing of the fast-relaxation spectrum is found to show a power-law behavior with…
gamma-Ray irradiation of chitosan flakes and introduction of hydrophobic chains onto hydroxyl groups are discussed. At 25 kGy, chain degradation without cross-linking reduces the molecular weight to one-fourth; however, structural characterization by FT-IR, 1H NMR, and 13C CP/MAS NMR indicates that the saccharide unit…
The selective catalytic reduction (SCR) of NO to N 2 by NH 3 over TiO 2, ZrO 2, and Al 2 O 3 was studied at 90 °C using a feed stream that was simulated to represent the effluent from a coal combustion boiler. The effects of SO 2 on the reduction of NO were studied. It is interesting that the SCR reaction was interrup…
Direct near-IR excitation of Yb(3+) 2F(7/2)-->(2)F(5/2) levels at 10126, 10138, and 10596 cm(-1) in CsMnBr3:0.5%Yb(3+) leads to three types of luminescence at cryogenic temperatures: near-IR Yb(3+) emission and green and red upconverted luminescence. The green luminescence around 20 000 cm(-1) is identified as coopera…
Poly(phenyllactide) was synthesized via the ring-opening polymerization of phenyllactide, the dimer of phenyllactic acid. Phenyllactide was synthesized by two methods, the solution phase condensation of L-phenyllactic acid and by thermal cracking of low molecular weight phenyllactic acid oligomers. The poor solubility…
We have studied the crystal structure of ${\mathrm{LaMnO}}_{3}$ under pressure up to 80 kbar at room temperature by TOF neutron diffraction. The analysis of the crystal structure as a function of pressure has revealed that the Jahn-Teller (JT) distortion is stable up to about 70 kbar. The contraction of the ${\mathrm{…
Immobilized gold colloid particles coated with a C-18 alkylsilane layer have been characterized as a substrate for surface-enhanced Raman scattering (SERS) studies of adsorption onto hydrophobic surfaces. Atomic force microscopy images, optical extinction spectra, and SERS measurements are reported as a function of ac…
The kinetic parameters for the dehydration of bentonite from Turkey, KSF and K10 were determined by using dynamic TG techniques. The Ozawa method is better for the dehydration of the clay samples than the first order equation of Coats and Redfern. The former function calculates consistently higher activation energies…
The magnetoresistive ``electron''-doped materials ${\mathrm{CaMnO}}_{3\ensuremath{-}\ensuremath{\delta}}$ $(\ensuremath{\delta}=0.06,0.11)$ have been investigated using powder neutron diffraction. The two materials are n-type semiconductors which exhibit antiferromagnetic ordering at ${T}_{N}\ensuremath{\sim}125\mathr…
Abstract Surface‐pattern formation in thin block copolymer films was investigated by utilizing a high‐throughput methodology to validate the combinatorial measurement approach and to demonstrate the value of the combinatorial method for scientific investigation. We constructed measurement libraries from images of subr…
SQUID magnetometry and M ö ssbauer spectroscopy has been combined to quantitatively characterize the superparamagnetic relaxation of MnFe 2 O 4 nanoparticles with a mean size of 7.4 nm. The key parameter for understanding and controlling the superparamagnetic properties of nanoparticles, the anisotropy constant K has…
The electronic and magnetic properties of perovskite superlattices composed of five unit-cell layers of ferromagnetic metal ${\mathrm{La}}_{0.6}{\mathrm{Sr}}_{0.4}{\mathrm{MnO}}_{3}$ and nonmagnetic band insulator ${\mathrm{SrTiO}}_{3}$ with varying layer thickness have been systematically investigated. The superlatti…
The 1963 discovery of ferroelectricity in YMnO(3) was accompanied by an experimental Curie temperature (T(c)) reported as 913 K; this value was revised to 1270 K in the following decade. Subsequently, YInO(3) was shown to be isostructural with YMnO(3) and later demonstrated to satisfy the structural criteria for ferro…