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71.
Subbiah Meenakshisundaram RM. Sockalingam 《Journal of molecular catalysis. A, Chemical》2000,160(2):269-275
Catalytic activity of Os(VIII) in the oxidation of some twenty organic sulfides with sodium salt of N-chlorobenzenesulfonamide (CAB) has been investigated in alkaline (pH8.7) t-butanol–water (1:1 v/v) medium. Significant retarding influence of [OH−] on the reactivity is exhibited. The catalysed reaction is strongly accelerated in the presence of Hg(II). Imperfections are observed in the linear Hammett relationship in the case of –NO2 substituents. 相似文献
72.
B. Lambert B. Deveaud A. Chomette A. Regreny B. Sermage 《Superlattices and Microstructures》1989,5(4)
Owing to the use of a high sensitivity streak camera we are able to observe photoluminescence (PL) decays with excitation density as low as 1014 photocarriers cm−3 per pulse. At such low densities photoexcited electrons are the minoritar carriers in our residual p-type MBE materials and they move freely. By varying the excitation density we are able to evidence the transition from electron transport regime to ambipolar motion. We have studied a series of samples superlattices (SLs) of different periods and AlGaAs reference alloy with an enlarged well (EW) located at about 1 μm from the surface. The vertical transport in these structures is analysed by measuring the dynamics of the photoluminescence. 相似文献
73.
T. Li J. C. Carrano C. J. Eiting P. A. Grudowski D. J. H. Lambert H. K. Kwon R. D. Dupuis J. C. Campbell R. T. Tober 《Fiber and Integrated Optics》2001,20(2):125-131
A resonant-cavity-enhanced p-i-n photodetector has been designed and analyzed to operate at a wavelength of 360 nm based on the AlxGa1-xN material system. The novel approach has been adopted of using epitaxial AlN/AlxGa1-xN quarter-wave stacks as the distributed Bragg reflector that serves as the front mirror. An AlxGa1-xN absorptive filter layer is incorporated to suppress all but one resonant mode to ensure single, narrow-band operation. This device structure is projected to achieve wavelength selective, high speed, and high quantum efficiency operation in the ultraviolet. MOCVD-grown 6 1/2-pair AlN/AlxGa1-x 相似文献
74.
75.
We solve the model for the flow of nitrogen, vapor, and water in a porous medium, neglecting compressibility, heat conductivity,
and capillary effects. Our choice of injection conditions is determined by the application to clean up polluted sites. We
study all mathematical structures, such as rarefaction, shock waves, and their bifurcations; we also develop a systematic
method to find fundamental solutions for thermal compositional flows in porous media. In addition, we unexpectedly find a
rarefaction evaporation wave which has not been previously reported in any other study. 相似文献
76.
77.
78.
S. Haiber H. Herzog P. Burba B. Gosciniak J. Lambert 《Analytical and bioanalytical chemistry》2001,369(5):457-460
Two-dimensional phase sensitive C,H correlation spectra were successfully applied to the quantification of carbohydrate substructures in aquatic humic substance (HS) fractions obtained by tangential flow multistage ultrafiltration (TFMSTUF) of a selected bog water HS (HO13, German Research Program DFG-ROSIG) as well as a river HS (Suwannee River Fulvic Acid Reference of the International Humic Substances Society, IHSS). It turns out that after size fractionation the HS samples give very well resolved C,H-correlation spectra which offer a great potential for substructure quantification. Details of the combined substructure quantification technique, novel in HS characterization, are presented. The results of the combined procedure point out that carbohydrate moieties predominantly occur in higher molecular mass fractions (> 10 kDa) of isolated HS. 相似文献
79.
Journal of Nanoparticle Research - 相似文献
80.
Christopher B. Kelly Kyle M. Lambert Michael A. Mercadante John M. Ovian Prof. William F. Bailey Prof. Nicholas E. Leadbeater 《Angewandte Chemie (International ed. in English)》2015,54(14):4241-4245
A scalable, high yielding, rapid route to access an array of nitriles from aldehydes mediated by an oxoammonium salt (4‐acetylamino‐2,2,6,6‐tetramethylpiperidine‐1‐oxoammonium tetrafluoroborate) and hexamethyldisilazane (HMDS) as an ammonia surrogate has been developed. The reaction likely involves two distinct chemical transformations: reversible silyl‐imine formation between HMDS and an aldehyde, followed by oxidation mediated by the oxoammonium salt and desilylation to furnish a nitrile. The spent oxidant can be easily recovered and used to regenerate the oxoammonium salt oxidant. 相似文献