Materials Literature
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We study dendritic microstructure evolution using an adaptive grid, finite element method applied to a phase-field model. The computational complexity of our algorithm, per unit time, scales linearly with system size, allowing simulations on very large lattices. We present computations on a ${2}^{17}\ifmmode\times\els…
Silicon nanowires have been synthesized in high yield and high purity by using a high-temperature laser-ablation method with growth rates ranging from 10 to 80 μm/h. Transmission electron microscopic investigation shows that the nanowires are crystalline Si, and have diameters ranging from 3 to 43 nm and length up to…
Synthesis and characterization of a new series of low molecular weight (MW = 500–3000) OH-terminated linear aliphatic unsaturated polyesters based on cis-2-butene-1,4-diol and oxalic to sebacic acid were investigated. Direct polycondensation and transesterification methods were used for the syntheses. The latter was r…
3151-3154
Surface modification of poly(aryl ether ether ketone) (PEEK) film surfaces by oxygen plasma treatment was investigated. Two procedures, the direct plasma treatment and the remote oxygen plasma treatment, were used as oxygen plasma treatments, and the efficiency of the hydrophilic modification was discussed. The direct…
Studies of PANI protonation in fluorinated alcohols are presented. Three solvents have been tested, namely 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP), 1,1,1,3,3,3-hexafluoro-2-phenyl-2-propanol (HFPP), and 1,1,1,3,3,3-hexafluoro-2-( p -tolyl)-propanol (HFTP). It has been demonstrated that the degree of the broadening of…
Blends of poly( N -phenyl-2-(2‘-thienyl)-5-(5‘‘-vinyl-2‘‘-thienyl)pyrrole) ( PSNPhS ) and poly( N -vinylcarbazole) ( PVK ) were prepared in mass ratios of 1:4, 3:2, and 4:1. Their electrochromic properties were characterized using cyclic voltammetry, in situ spectroelectrochemistry, and spectrocolorimetry. Solid-state…
The binding of several lanthanide(III) ions to anthracycline antitumor antibiotics daunomycin and adriamycin in methanol and aqueous solutions has been studied by means of optical and 2D NMR (COSY, TOCSY, and EXSY) techniques. These results indicate that a 1:1 Yb(3+)-drug complex (1) is the predominant complex at a me…
A flexible polyurethane foam fire-retarded with 7.8% tris (1,3-dichloro-2-propyl) phosphate (TDCPP) was found to lose by volatilization 80% of this material at 200°C, a temperature at which there is as yet little decomposition of the foam. It is therefore to be expected that when this foam burns, most of its TDCPP wil…
Rates of isobutane dehydrogenation and isobutene hydrogenation were measured over Pt/Sn/SiO 2, Pt/Sn/K/SiO 2, and Pt/Sn/K−L-zeolite catalysts at temperatures from 673 to 773 K and at various partial pressures for a total pressure of 1 atm. Addition of potassium to Pt/Sn/SiO 2 enhances the rate of isobutene hydrogenati…
Complexes of bis(hexafluoroacetylacetonato)copper(II) [Cu(hfac)(2)] ligated with 3- and 4-(N-oxyl-tert-butylamino)pyridines (3NOPy and 4NOPy) and N-{3- and 4-(N-oxyl-tert-butylamino)phenyl}imidazoles (3NOIm and 4NOIm) were prepared. The 1:2 complexes [Cu(hfac)(2)(3NOPy and 4NOPy)(2)] have hexacoordinated octahedral st…
An on-line experimental technique was developed for the measurement of fiber diameter and temperature during the melt-blowing process. The experimentally determined diameters and temperatures were compared with a mathematical model for melt-blowing.
Cellulose, cellulose diacetate (CDA), cellulose triacetate (CTA), cellulose nitrate (CN), and cellulose phosphate (CP) were subjected to dynamic thermogravimetry in nitrogen and air. The thermostability of the cellulose and its esters was estimated, taking into account the values of initial thermal degradation tempera…
The relaxation dynamics of charge carriers in 4 nm CdS colloidal quantum dots are studied by means of picosecond time-resolved fluorescence and femtosecond transient absorption experiments. We also studied the effects of the adsorption of viologen derivatives as electron acceptors on the surface of these particles. Fr…
Using microscopic models in which both photons and excitons are treated as microscopic degrees of freedom, we discuss polaritons of two cases: One is the case when excitonic parameters are time dependent. The time dependence causes creation of polaritons from a "false vacuum." % We present the creation spectra of both…
We consider generation of an electrical pulse by an optical pulse in the ``virtual excitation'' regime. The electronic system, which is any electro-optic material including a quantum well structure biased by a dc electric field, is assumed to be coupled to an external circuit. It is found that the photon frequency is…
The electronic properties of metal-ceramic interfaces are found to vary with the size of the interface in the range of 3–100 nm. Interface properties can be extracted from variations in apparent heights of metal clusters, as measured by scanning tunneling microscopy, of small clusters on atomically smooth oxide surfac…
In order to investigate the effect of concentration in biological processes such as protein folding, small angle neutron scattering measurements were used to determine the second virial coefficient of solutions of both native and strongly denatured phosphoglycerate kinase and the radius of gyration of the protein at z…
A general method is introduced for the rapid and simultaneous evaluation of each member of large encoded catalyst libraries for the ability to catalyze a reaction in solution. The procedure was used to select active catalysts from a library of potential polymer-bound multifunctional catalysts. From approximately 7000…
Copolymers of 1,1‘-binaphthyl and oligothiophenes have been synthesized by using the Suzuki coupling reaction. These polymers are soluble in organic solvents such as chloroform and THF. The higher molecular weight polymers have shown high thermal stability. These binaphthyl−thiophene copolymers have well-defined conju…