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1.
de Farias RF de Souza JM de Melo JV Airoldi C 《Journal of colloid and interface science》1999,212(1):123-129
The effects exhibited by adsorbed conducting polyaniline on the redox process on a molybdenum oxide surface were studied. Thermogravimetric results indicate a 4% polyaniline deposition. Cyclic voltammograms of the adsorbed polymer on MoO3 show that polyaniline exerts remarkable effects on the molybdenum blue oxidation-reduction process, with oxidation and reduction potentials of 0.33 and 0.18 V, respectively. This effect strongly enhances the electrode response, and can be used as an important tool in qualitative and/or quantitative determinations of molybdenum in solution as well as in any substrate. Copyright 1999 Academic Press. 相似文献
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Vara Prasad JV 《Organic letters》2000,2(8):1069-1072
[formula: see text] A simple synthesis of heterocyclic thiosulfonates containing indole, indoline, benzoimidazole, and quinoxaline rings is described. The synthesis of these thiosulfonates involves the preparation of the appropriately substituted thiols followed by sulfonylation to give thiosulfonates. The corresponding thiols were prepared in a simple and efficient manner by using a thiocyanation reaction either prior to heterocycle ring formation or after heterocycle ring formation. These thiosulfonates were coupled successfully to the 5,6-dihydropyran-2-one ring to give products that showed excellent HIV protease activity. 相似文献
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An experimental investigation has been undertaken to improve understanding of the role of the obturator and detonations in
the subdetonative ram accelerator starting process. Ram accelerator start experiments were conducted with various obturator
geometries to determine the obturator dynamics and assess its effect on the outcome of a start attempt. The obturator rapidly
decelerates upon entrance and then moves backwards. Reversal of direction occurs more rapidly after propellant ignition, for
less massive obturators, and solid geometries. Perforated geometries and decreasing obturator mass are less conducive to igniting
a given propellant, as evidenced by the flowfield and start attempt outcome data presented. Wave unstarts were observed to
occur with and without detonations, indicating more than one mechanism responsible for this type of start failure. Piston-initiated
detonation experiments were conducted by firing the obturators without the ram accelerator projectile. The piston experiments
identified the detonation limits for a wide range of propellants, but were found to not always be indicative of the upper
Mach number at which a ram accelerator can be successfully started. In some instances a successful start or wave fall-off
would occur at Mach numbers above which a piston alone detonated the propellant. Thus, the projectile can play a mitigating
role in detonation initiation and use of piston detonation limits to quantitatively define a detonation wave unstart limit
was not realized.
Received 6 April 1998 / Accepted 15 January 1999 相似文献
7.
Julius Schmidt Hans Rupe Fritz Pregl Horst Bruckner und Emil Abderhalden 《Fresenius' Journal of Analytical Chemistry》1930,81(8-9):323-324
Ohne Zusammenfassung 相似文献
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Gottfried Bruckner Johannes Elschner 《Mathematical Methods in the Applied Sciences》2005,28(7):757-778
We consider the inverse problem of recovering a 2D periodic structure from scattered waves measured above and below the structure. We discuss convergence and implementation of an optimization method for solving the inverse TE transmission problem, following an approach first developed by Kirsch and Kress for acoustic obstacle scattering. The convergence analysis includes the case of Lipschitz grating profiles and relies on variational methods and solvability properties of periodic boundary integral equations. Numerical results for exact and noisy data demonstrate the practicability of the inversion algorithm. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
10.
Oligopeptides with the sequence Z(GlyProPro)nOBut (n = 3–7) were synthesized along a clasical pathway. Generally long fragments were condensed in order to allow an easy separation of the products from the reactants. It is established by molecular weight determination and measurements of circular dichroism that the peptides form the collagen-like triple helix in methanol and that they assume the random coil conformation in dilute acetic acid. The circular dichroism spectra agree reasonably well with the corresponding spectra for (ProProGly)10 which was obtained by solid phase synthesis in another laboratory. 相似文献