Now showing items 161-170 of 204
The dynamical transition to step-flow growth during molecular-beam epitaxy of GaAs(00l)
(Elsevier, 1993-12-20)
Scanning tunneling microscopy studies have been performed on GaAs homoepitaxial films grown by molecular-beam epitaxy. Images show that in the earliest stages of deposition the morphology oscillates between one with ...
M x –O y –Si z bonding models for silica-supported Ziegler–Natta catalysts
(John Wiley & Sons, Ltd., 1999-04)
Three reactants, polyhedral oligosilsesquioxanes (POSS) (c-C 6 H 11 ) 7 (Si 7 O 9 )(OH) 3 (1), butylethylmagnesium (2) and titanium tetrachloride TiCl 4 (3), react in three different ways according to the order of addition ...
Application of the 2-azaallyl anion cycloaddition method to syntheses of (+/-)-crinine and (+/-)-6-epicrinine
(Elsevier, 1994-12-05)
Transmetalation of the (2-azaallyl)stannane 9 with n-BuLi produced the 2-azaallyl anion 12 which underwent an intramolecular cycloaddition with an alkene to give the perhydroindole 10 in 80% yield as a single stereoisomer. ...
The mechanism of the oxidation of propene to acrolein over antimony-tin mixed oxide catalysts
(Elsevier, 1990-05)
The oxidation of propenes such as 13CH2=CH---CH,3, CH2=CH-CD3, cis---CHD=CD---CH3, and CH2---CH---CH3 was studied over Sb6O13, SnO2, and Sb---Sn mixed oxide catalysts. The results with 13CH2=CH---CH3 and CH2=CH---CD3 were ...
Ammonia adsorption and decomposition on the GaAs(100)-c(8 x 2) surface
(Elsevier, 1994-12-20)
The effect of ammonia exposure and substrate temperature on the reaction of ammonia with GaAs(100)-c(8 x 2) has been studied using temperature programmed desorption (TPD), X-ray photoelectron spectroscopy (XPS), and high ...
Thermodynamics of the (lanthanum + strontium + copper + oxygen) high-Tc superconductors I. Heat capacities of SrCuO2, Sr2CuO3, and Sr14Cu24O41
(Elsevier, 1990-11)
The subambient heat capacities of three (SrO)x(CuO)y inter-oxide samples with x = Y = 1; x = 2, y = 1; and x = 1, y = 2, were measured as a part of an investigation into the chemical thermodynamics of the high-Tc superconducting ...
(1E,3E)-4-acetoxy-1-phenyldimethylsilyl-1,3-butadiene as a surrogate for (1E,3E)-1,4- diacetoxy-1,3-butadiene: a highly efficient synthesis of (+/-)-shikimic acid
(Elsevier, 1990)
The 5-step synthesis of (+/-)-shikimic acid has been achieved in 55% overall yield from (1E,3E)-4-acetoxy-1-phenyldimethylsilyl-1,3-butadiene, starting with its Diels-Alder reaction with 2-(trimethylsilyl)ethyl acrylate ...
Synthesis of novel polyhydroxylated quinolizidines: Ring expanded analogs of glycosidase inhibitory indolizidines
(Elsevier, 1993-12-17)
Two polyhydroxylated quinolizidines, (1R,2R,3R,9S,9aR)-1,2,3,9-tetrahydroxyquinolizidine 9 and (1R,2R,3R,9R,9aS-1,2,3,9-tetrahydroxyquinolizidine 10, have been synthesized by the reductive double cyclization of 15[alpha] ...
Adhesion at a heterophase interface: First-principles study of Mo(001)/MoSi 2 (001)
(Kluwer Academic Publishers; Springer Science+Business Media, 1994-09)
The bonding characteristics, interfacial energetics, and electronic structure associated with adhesion at the Mo-MoSi 2 (001) heterophase interface are investigated using the first-principles, self-consistent local orbital ...