Anionic rearrangement of organosilyl groups from carbon to carbon in β-triorganosilylethylammonium ylides

Reaction of β-triorganosilylethylammonium iodides with n-butyllithium in a HMPA/ether mixture at ?15 to ?20°C gave the corresponding α-triorganosilylalkylamines which were produced by 1,4-anionic rearrangement of organosilyl groups from carbon to carbon in β-triorganosilylethylammonium ylides. Small amounts of the Hofmann elimination products, triorganovinylsilane and N,N-dialkyl-2-trimethylsilylethylamines, were also detected.     

Preparation and Characterization of Titania Thin Films from Aqueous Solutions

Dip- or spin-coating and characterization of titania (TiO₂) thin films from various aqueous solutions have been studied. The aqueous titanium solutions mainly used in this study were halogen- and chelate-free solutions with the concentrations up to 1.4 M derived from titanium isopropoxide (TIP) with tetramethylammonium hydroxide (TMAOH) or some alkylamines, while aqueous and alcoholic solutions containing titanium atoms stabilized chelating ligands were examined for comparison. The TiO₂ films prepared from the TIP-TMAOH solution were already crystallized at 350°C to anatase form and those formed at 600°C had high transparency and refractive indices of 2.40. No carbon residue in the film prepared at 400°C was detected by XPS. The pure anatase form was sustained up to 850°C. Interestingly, it was found that the (004) preferentially oriented anatase films were obtained from TIP-lactic acid (LA) system until 700°C. The solutions containing citric acid (CA) or alkanolamines yielded anatase and rutile form fired at the temperatures equal to or higher than 600°C. Carbon residue was detected in the film fired at 400°C. The film thickness monotonically decreased from the upper to the bottom ends of the substrate. However, it was found that the thickness uniformity was drastically improved by an addition of sucrose to the aqueous solutions. The effects of the solution composition and polyhydroxy compounds on the crystal modifications of formed films and the film uniformity are discussed.     

Synthesis of CO2 Copolymer Based Polyurethane Foams

CO2-copolymer based polyurethane foams were synthesized and characterized in this paper. The foams were found to have higher strength and lower heat of combustion than the conventional polyether polyurethane foams. They may find wide applications in many fields.     

Molecular structure and photoreaction of poly(methylpropylsilane)

The molecular structure and photoreaction of poly(methylpropylsilane) (PMPrS) are investigated. The ²⁹Si-NMR spectra reveal that PMPrS is a linear polymer with no blanches. Fine multiple splitting of ²⁹Si-NMR is observed at room temperature. This multiple splitting is thought to be due to molecular conformation. The photo-oxidation reaction of the PMPrS film is found to be caused by light irradiation at the UV absorption band, 330 nm. Quantum efficiencies of scission and crosslink related to photodegradation are evaluated. There is little difference in either the molecular structure or photoreactivities between the high and the low molecular weight portions of the bimodal molecular weight distributions of PMPrS.     

Synthetic studies on mitomycins. 2. A synthesis of 9a-hydroxy-5,8-dideoxomitosane skeleton through a novel retroaldol type of ring-opening reaction.

A synthesis of 9a-hydroxy-5,8-dideoxomitosanes was accomplished by the transannular cyclization of hydro-1-benzazocinone intermediates derived from 3-(2,5-dioxo-1-methylcyclopentyl)-6-methyl-p-phenylenediamine derivatives. These mitosanes were led to the 8-membered ring system by an oxidative ring-opening reaction.     

Linearly perturbed generalized polyhedral normal cone mappings and applications

Under a mild regularity assumption, we derive an exact formula for the Fréchet coderivative and some estimates for the Mordukhovich coderivative of the normal cone mappings of perturbed generalized polyhedra in reflexive Banach spaces. Assume in addition that the generating elements are linearly independent and some qualification condition holds, the Lipschitzian stability of the parameterized variational inequalities over the right-hand side perturbed generalized polyhedra is characterized using the initial data.     

Structural and nutritional characterization of macromolecular complexes in new bioenergy feedstock by infrared radiation with advanced molecular spectroscopy and spectral chemometrics

The objective of this research was to characterize new bioenergy feedstocks, in comparison with conventional feedstock, by infrared radiation with advanced molecular spectroscopy in terms of association of molecular structure with nutrient delivery in ruminant livestock systems. This study focused on the effect of molecular structure changes on nutrient delivery to ruminant systems. The updated methods of various lab, animal, and modeling techniques for nutrient delivery study in ruminant livestock systems were reviewed. The molecular spectral analyses used in this study included both univariate and multivariate molecular spectral analyses. The relationship between molecular structural features and truly absorbed nutrient supply was quantified. The research provides information on how inherent structure features in the new types of bioenergy feedstock on a molecular basis affected nutrient delivery in ruminant livestock systems.     

Structural and electrical properties of nickel–iron thin film on copper substrate for dynamic random access memory applications

Using pulse electrodeposition technique, nano crystalline NiFe films were deposited on conductive copper substrates, under galvanostatic mode in an ultrasonic field at different conditions such as pulse current magnitude, deposition time and ultrasonic bath temperature. As-prepared NiFe/Cu thin films were characterized for phase analysis, surface morphology, surface roughness and resistivity measurements. The results show that the use of ultrasonic bath at room temperature has reduced the surface roughness, resistivity, average grain size and crystallite size of NiFe/Cu thin films. The resistivity is reduced with increasing deposition current from 44.2 µΩ cm at 40 mA to 33.0 µΩ cm at 100 mA. On the other hand, a significant drop of the resistivity from 35.7 to 9.4 µΩ cm is observed if the deposition time was reduced from 5 to 3 min.