Materials Literature
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The rate constants for the dissociation of AlMe 3 from [ 2 ][B(C 6 F 5 ) 4 ] and related M/Al dimers have been determined by selective population inversion ( 1 H NMR). The results predict correctly that (EBI)ZrMe + will be a better carboalumination catalyst than (EBTHI)ZrMe + .
The reactions of the ligands N-methyldiethanol amine and N-ethyldiethanol amine (abbreviated H(2)mdea and H(2)edea, respectively) with [Mn(12)O(12)(O(2)CCH(3))(16)(H(2)O)(4)] yield novel dodecanuclear wheel-shaped products. The capability of the ligands H(2)mdea and H(2)edea to support wheel structures in metals other…
A study using ab initio MO calculations and frontier orbital theory has been performed to investigate the effect of substitutional boron on the electronic structure and reactivity of eight-ring carbon model structures. This theoretical analysis confirmed that boron substitution in the carbon lattice can result in two…
Novel bolaamphiphilic triblockmolecules consisting of a rigid biphenyl unit, with a polar 2,3-dihydroxypropyloxy group and a phenolic OH group at opposite ends, as well as a semiperfluorinated chain in a lateral position have been synthesized via palladium catalyzed cross coupling reactions as the key steps. The therm…
Fluorination and structural change of highly ordered mesoporous carbons were studied. Mesoporous and fluorinated carbons with ordered cubic structure were synthesized and characterized with TEM, FTIR, adsorption, and EDX.
Nitroaromatic compounds enter the environment through their use as explosives, pesticides, solvents, and synthetic intermediates in the manufacturing of dyes, perfumes, and drugs. Recent studies have found that many nitroaromatic compounds are strongly retained by smectites, especially K+-saturated smectites. Sorption…
Polyamidoamine (PAMAM) dendrimers up to the third generation were grown for the first time inside the channels of a large-pore (6.5 nm) MCM-41 silica. In-depth characterization of such materials showed that the dendrimers grew inside the channels. The third generation was found to almost completely fill the pore syste…
An environmentally friendly process of synthesizing Zr-incorporated mesoporous SBA-15 silica materials with the Zr content up to 0.1 Zr/Si atomic ratio and of well-ordered pore structure, high surface area, and narrow pore-size distribution was developed, where no addition of mineral acids was necessary. The main stra…
In this article we show that the reconstructions of semiconductor surfaces can be determined using a genetic procedure. Coupled with highly optimized interatomic potentials, the present approach represents an efficient tool for finding and sorting good structural candidates for further electronic structure calculation…
We give experimental and theoretical evidence of the Rashba effect at the magnetic rare-earth metal surface Gd(0001). The Rashba effect is substantially enhanced and the Rashba parameter changes its sign when a metal-oxide surface layer is formed. The experimental observations are quantitatively described by ab initio…
Natural gas is an extremely attractive fuel for use in fuel cells. Steam-reforming and oxidation of methane are particularly important for the direct methane fuel cell. A perovskite-related material, La 0.75 Sr 0.25 Cr 0.5 Fe 0.5 O 3 - δ (LSCrF), has been synthesized, and its catalytic properties as a potential anode…
We demonstrate the self-organization of CdSe nanorods into nematic, smectic, and crystalline solids. Layered colloidal crystals of CdSe nanorods grow by slow destabilization of a nanocrystal solution upon allowing the diffusion of a nonsolvent into the colloidal solution of nanocrystals. The colloidal crystals of nano…
A versatile bis(2,5-dimethyl-3-thienyl)-1,10-phenanthroline photochromic ligand has been successfully synthesized via a Suzuki cross-coupling reaction. The excitation wavelength for photochromic reaction of the dithienylphenanthroline could be extended from lambda </= 340 nm in the UV region to ca. 480 nm in the visib…
Arc-synthesized single-walled carbon nanotubes have been purified through preparative electrophoresis in agarose gel and glass bead matrixes. Two major impurities were isolated: fluorescent carbon and short tubular carbon. Analysis of these two classes of impurities was done. The methods described may be readily exten…
The adsorption phenomenon of neutral particles in a sample having the shape of a slab is theoretically investigated by using a particular form for the kinetic equation at the limiting surfaces. The time evolution of the bulk and surface densities is determined in a closed form by means of a simple expression. A discus…
The oscillation of ultrasonic cavitation bubbles at various dissolved-air concentrations in a sonochemical reaction field is investigated experimentally by laser-light scattering. When a thin light sheet, finer than half the wavelength of sound, is introduced into the cavitation bubbles at an antinode of sound pressur…
Hydrogels and macroscopic fibers are formed through the salt-induced self-assembly of water-soluble polycationic phosphorus dendrimers. Interestingly, the hydrogels are thermoreversible and the sol-gel transition temperature can be easily tuned in a wide range of temperatures (approximately 2-80 degrees C). The effect…
Abstract Summary: A new physical method of fabricating hollow spheres from different polymers has been developed. In this method, emulsions were prepared by mixing organic solutions of polystyrene, poly( D , L ‐lactide‐ co ‐glycolide) (PLGA), and bacterial poly(3‐hydroxybutyrate‐ co ‐3‐hydroxyvalerate) (PHBV), water,…
ABSTRACT This paper examines fatigue crack paths in coarse‐grained magnesium alloys. Visualization of the microstructure by etching and continuous crack monitoring with a microscope provide evidence of the crack‐grain interaction at different fatigue crack growth regimes. Near‐threshold fatigue crack growth promotes t…
The effect of temperature on the adsorption isotherms for cupric and cadmium ions by corncob particles was investigated. The uptake of the two types of ions by corncob particles increased with temperature in the ranges between 25°C and 65°C and between 15°C and 65°C for copper and cadmium, respectively. In addition, a…