Materials Literature
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Two diaminocalix[4]arene monomers were synthesized from p-tert-butylcalix[4]arene through a 4-step reaction sequence. New copoly(amic acid)s containing calix[4]arene moieties on the polymer backbone were successfully synthesized in N-methyl-2-pyrrolidone by polycondensations of 4,4′-oxydiphthalic anhydride (ODPA) with…
The combination of time-of-flight secondary mass spectrometry (ToF-SIMS) and monochromatized x-ray photoelectron spectroscopy (XPS) has proved to be a valuable tool for the analysis of chemically modified polymer surfaces. By applying these techniques in situ, together with a plasma modification chamber and a Knudsen…
We studied a red photoluminescence (PL) band at about 1.8 eV with full width at half maximum of 0.2–0.4 eV in a series of oxygen deficient-type silicas before and after γ irradiation. The decay lifetime of the PL was estimated to be about 200 ns. The PL excitation peak was found to be located at 2.1 eV. The intensity…
A principle of constructing hysteresis models with stable minor loops is proposed. It has been found that a modeled reversal curve of any order can be obtained by copying (transplanting) the segment of the first-order curve that has the same overall dimensions and is the nearest to the modeled curve in the M- (or B-)…
Abstract 1,3,5-tris{p-(N-oxy-N-tert-butylamino)phenyl}benzene (2) is known as a persistent triradical with a quartet ground state. A new triradical with a triazine skeleton was synthesized and characterized. The nitroxide triradical with triazine derivative 2,4,6-tris{p-(N-oxy-N-tert-butylamino)phenyl}-1,3,5-triazine…
The inelastic neutron scattering spectra of the polycrystalline n-alkanes, 5<n<25, have been obtained at ∼25 K. At this temperature the n-alkane molecules are extended in their all-trans configuration. The spectral region from 200 to 600 cm−1 is reported with emphasis on the higher frequency longitudinal…
The exchange of oxygen atoms between acetate, glutaryl-CoA, and the catalytic glutamate residue in glutaconate CoA-transferase from Acidaminococcus fermentans was analyzed using [(18)O(2)]acetate together with matrix-assisted laser desorption/ionization time of flight mass spectrometry of an appropriate undecapeptide.…
Monodisperse polymeric nanospheres, which consist of polystyrene cores and poly(ethylene glycol) (PEG) branches on their surfaces, were prepared by the dispersion copolymerization of styrene (St) with PEG macromonomers that had a methacryloyl (MMA-PEG) or p-vinylbenzyl (St-PEG) end group in various organic solvent/wat…
The influence of processing parameters on the growth and morphology of hydrothermally derived lead titanate (PbTiO 3 ) powders was investigated. PbTiO 3 powder was synthesized by suspending nanocrystalline powders of TiO 2 in aqueous solutions of KOH and Pb(CH 3 COO) 2 ·3H 2 O at temperatures ranging from 120° to 200°…
Dehydroxylation of diaspore has been followed by a combination of differential thermal analysis (DTA) and infrared emission spectroscopy (IES). The DTA endotherm of diaspore is not simple, and two inflections are observed at 505 and 531 °C. Dehydroxylation shows that diaspore loses 15% of its weight upon dehydroxylati…
The purpose of this study was to evaluate the safety and efficacy of a manganese chloride-based oral magnetic resonance (MR) contrast agent during a Phase III multisite clinical trial. Two hundred seventeen patients were enrolled who were already scheduled for MRI of the abdomen and/or pelvis. In this group of patient…
A scanning electron microscope with a thermal field emission gun (FEGSEM) is found to offer significant improvements in electron backscatter diffraction performance over a conventional W-filament scanning microscope. The spatial resolution is improved by a factor of approximately 3 in the FEGSEM and is optimized at pr…
Organization of a linear polysilane chain in a spincast film was controlled in response to the surface photochromic reaction of an azobenzene (Az)-containing monolayer. The kinetics of crystallization as well as the final ratio of crystalline/disordered of poly(di- n -hexylsilane) depended strongly on the geometry of…
The fluorescence behavior of 1,1′-dimethyl-2,2′-carbocyanine and p-N,N-dimethylamino-styryl-2-ethylpyridinium was investigated in several epoxy systems. Time-correlated single photon counting was used for all fluorescence measurements to obtain the rate constant for viscosity or mobility-dependent nonradiative process…
The kinetics of the polymerization of ε-caprolactone initiated with various Lewis acid metal alkoxides (Al, Zr and rare earths such as Y, Sm, Nd) in the presence of excess alcohol has been investigated. Whatever the metal, the activity depends strongly on the [Alcohol]/[Metal] ratio and goes through a maximum, except…
Partially phase-separated liquid-crystal/polymer dispersions display highly fibrillar domain morphologies that are dramatically different from the typical structures found in isotropic mixtures. To explain this, we numerically explore the coupling between phase ordering and phase-separation kinetics in model two-dimen…
The electron microscopy investigation of ${\mathrm{Pr}}_{0.7}{\mathrm{Ca}}_{0.3}{\mathrm{MnO}}_{3}$ shows that a complete charge disordering is induced in this phase by electron irradiation at 92 K, the disordered state remaining stable at this temperature, even in the absence of irradiation. A model is proposed for t…
Two series of alkyl-modified molecular sieves were prepared using the FSM-16 mesoporous silica. The attachment of alkyl groups to the surface, the structure of the bonded layer, and changes in the mesoporous structure of the FSM-16 material upon functionalization were studied by means of high-resolution thermogravimet…
The role of the pyridoxyl functionality on pyridoxal 5‘-phosphate (PLP)-dependent enzymatic decarboxylation of α-amino acids has been examined using ab initio calculations at electron-correlated levels of theory (MP2/6-31G(d) and B3LYP/6-31G(d)). The zwitterionic reactant intermediates involved are used to measure the…
We present the effects of applied coil power on silicon etching in a high density inductively coupled plasma etcher in both the isotropic and anisotropic regimes. The experimentally obtained response surfaces were generated while changing four etching variables for the isotropic case and eight etching variables for th…