Materials Literature
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We present the first results on (0001) ZnO/(0001) epi-GaN/(0001) α-Al 2 O 3 heterostructure fabrication combining metal-organic vapour phase epitaxy and low-pressure chemical vapour deposition methods. The surface morphologies of the films were studied, and x-ray and reflection high-energy electron diffraction measure…
Fully saturated hydrocarbon polymers often exhibit superior stability toward thermal, oxidative, and radiation-induced degradation. Recent improvements in catalyst technology allow for the convenient synthesis of the saturated hydrocarbon poly(cyclohexylethylene) (PCHE) from polystyrene (PS) by heterogeneous catalytic…
Fluorinated surfaces are sought for a number of technologies requiring low surface energy, low adhesion, chemical robustness, among other desired properties. Bulk fluorinated materials (e.g., polymers) can be used, but their relative expense and difficult processing problems preclude widespread application. Small mole…
The structures of PrAlO 3 have been studied from room temperature to 10 K, using a combination of high resolution neutron and synchrotron powder diffraction data. At room temperature, PrAlO 3 has a rhombohedral structure in space group R c which transforms to an orthorhombic structure in Imma on lowering the temperatu…
We report on ${}^{13}\mathrm{C}$ nuclear magnetic resonance from $10$ up to $350$ K on single wall carbon nanotubes. The magic angle spinning NMR spectrum shows one isotropic line at $126$ ppm and the static spectrum a powder pattern typical for a curved graphene sheet. The T dependence of the spin-lattice relaxation…
Nanocomposite (Pr,Dy)2Fe14B/α-Fe magnets with compositions Pr8−xDyxFe86B6 (x=0, 0.5, 1, 1.5, and 2) have been synthesized by melt spinning using low wheel speeds in the range from 18 to 21.7 m/s. It has been found that the coercivity is significantly increased by Dy substitution. An optimum coercivity of 6.6 kOe is ob…
High-speed experimentation techniques have been applied in the synthesis and testing of silsesquioxane-based titanium catalysts (see picture) for the epoxidation of alkenes. Different solvents and organotrichlorosilanes were employed in the optimization of the hydrolytic condensation of silanes to open silsesquioxane…
Transamination reactions of [{(Me3Si)2N}2Sm(thf)2] with the dianion of either 1,1-di-(α-pyrrolyl)cyclohexane or diphenyl dipyrromethane led to the octanuclear complex shown in the picture and the hexanuclear complex [{[Ph2C(α-C4H3N)2]Sm}6(thf)3], respectively. Both clusters possess flat macrocyclic structures and reac…
We have reported conductivity spectra at different temperatures for fluoride glasses of compositions 0.50ZrF4–(0.40−x)BaF2–0.10YF3–xNaF in the frequency range from 10 Hz to 2 MHz. We have analyzed the spectra using conductivity formalism and obtained the frequency exponent, concentration, and hopping frequency of char…
By locating all relevant transition structures with a hybrid density functional method, we explored the three most reasonable mechanisms for H2O2 epoxidation of propenol catalyzed by methyltrioxorhenium (MTO), namely: (i) coordination of propenol as lone pair donor to rhenium mono- and bis-peroxo complexes followed by…
We have grown LaCa(4)O (BO(3))(3) (LaCOB), an isostructural member of GdCa(4)O(BO(3))(3) (GdCOB) family and characterized its nonlinear optical properties. At 1064nm, d(eff) of 0.52+/-0.05 pm /V and an angular sensitivity of 1224+/-184(cm rad)(-1) for type I frequency doubling in LaCOB were determined relative to thos…
Stable free radicals can be trapped inside a three-dimensional (3D) inorganic network. The formation of a new type of mixed-metal oxalate [MnII(H2O)CrIII(ox)3]− is induced by the presence of a cationic nitronyl nitroxide radical (rad+). The figure shows a stylized view of the 3D network ○ = Mn, • = Cr). This hybrid or…
We apply the Mori-Zwanzig projection operator formalism to obtain an expression for the frequency dependent specific heat $c(z)$ of a liquid. By using an exact transformation formula due to Lebowitz et al., we derive a relation between $c(z)$ and $K(t),$ the autocorrelation function of temperature fluctuations in the…
We report the results of simulation of radiation damage in zircon structure using the molecular dynamics technique. The phases of the damage production process, including the ballistic and thermal spike phases, are detected, quantified and visualized. We find that the higher ambient temperature results in substantial…
Fluorinated surfaces are sought for a number of technologies requiring low surface energy, low adhesion, chemical robustness, among other desired properties. Bulk fluorinated materials (e.g., polymers) can be used, but their relative expense and difficult processing problems preclude widespread application. Small mole…
Three types of iron-based oxide nanoparticles (weight compositions Fe2O3, BaFe2O4, and BaFe12O19) embedded in a polyethylene matrix are studied using the electron paramagnetic resonance technique. All nanoparticles are found to be multiphase. Thermal variations of electron paramagnetic resonance spectra reveal the pre…
Synthesis and anionic ring-opening polymerization of l -serine (Ser)- and l -threonine (Thr)-based cyclic carbonates, (2-oxo[1,3]dioxan-5-yl)carbamic acid benzyl ester (Z-S-CC), (4-methyl-2-oxo[1,3]dioxan-5-yl)carbamic acid benzyl ester (Z-T-CC), and (4-methyl-2-oxo[1,3]dioxan-5-yl)carbamic acid tert -butyl ester (Boc…
Here we describe the large-scale domain movements and hydration structure changes in the active-site cleft of unligated glutamate dehydrogenase. Glutamate dehydrogenase from Thermococcus profundus is composed of six identical subunits of M(r) 46K, each with two distinct domains of roughly equal size separated by a lar…
Dispersed fluorescence studies of the diatomic molecules MoC, RuC, and PdC are reported. New states identified in MoC and RuC are the […]2δ112σ1, 3,1Δ2 states and the […]2δ312σ1, 1Δ2 state, respectively. Five states are observed by dispersed fluorescence in PdC. The ground state is found to be […]2δ412σ2, 1Σ+, with th…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTLeft or Right, It Is a Matter of One Methylene UnitChristopher Y. Li, Stephen Z. D. Cheng, Xin Weng, Jason J. Ge, Feng Bai, John Z. Zhang, Bret H. Calhoun, Frank W. Harris, Liang-Chy Chien, and Bernard LotzView Author Information The Maurice Morton Institute and Depart…