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21.
22.
In previous work, a probabilistic approach to controlling difficulties of density in hyperbolic space led to a workable notion of optimal density for packings of bodies. In this paper we extend an ergodic theorem of Nevo to provide an appropriate definition of those packings to be considered optimally dense. Examples are given to illustrate various aspects of the density problem, in particular the shift in emphasis from the analysis of individual packings to spaces of packings. 相似文献
23.
Elizabeth A. Lewis 《Tetrahedron letters》2004,45(15):3059-3062
An efficient synthesis of C-functionalised cyclam macrocycles that employs bisaminal intermediates and allows N-substitution to be controlled is reported. 相似文献
24.
25.
On the analysis of two-dimensional discrete singular systems 总被引:2,自引:0,他引:2
In contrast to 1-D systems, the 2-D systems have no natural notion of causality. An artificial restriction traditionally imposed to allow recursive solution of these systems is that of recursibility. In this paper we study 2-Dsingular systems, taking advantage of the nonoriented or noncausal nature of these systems to provide a solution even if the requirement of recursibility does not hold. It is shown thatnonrecursible masks may be described using singular 2-D systems. The analysis approach relies on thefundamental matrix.Research supported by the US Fulbright Foundation in Greece and NSF Grant ECS-8805932. 相似文献
26.
Bortoletto D Goldberg M Horwitz N Mestayer MD Moneti GC Sharma V Shipsey IP Skwarnicki T Csorna SE Letson T Brock IC Ferguson T Artuso M Bebek C Berkelman K Blucher E Byrd J Cassel DG Cheu E Coffman DM Crawford G DeSalvo R DeWire JW Drell PS Ehrlich R Galik RS Gittelman B Gray SW Halling AM Hartill DL Heltsley BK Kandaswamy J Kowalewski R Kreinick DL Kubota Y Lewis JD Mistry NB Mueller J Namjoshi R Nandi S Nordberg E O'Grady C Peterson D Pisharody M Riley D Sapper M Silverman A Stone S Worden H 《Physical review letters》1989,62(21):2436-2439
27.
Alam MS Katayama N Kim IJ Li WC Lou XC Sun CR Bortoletto D Goldberg M Horwitz N Mestayer MD Moneti GC Sharma V Shipsey IP Skwarnicki T Csorna SE Letson T Brock IC Ferguson T Artuso M Bebek C Berkelman K Blucher E Byrd J Cassel DG Cheu E Coffman DM Crawford G DeSalvo R DeWire JW Drell PS Ehrlich R Galik RS Gittelman B Gray SW Halling AM Hartill DL Heltsley BK Kandaswamy J Kowalewski R Kreinick DL Kubota Y Lewis JD Mistry NB Mueller J Namjoshi R Nandi S Nordberg E O'Grady C Peterson D Pisharody M 《Physical review D: Particles and fields》1989,40(11):3790
28.
M. Jonathan Fray Paul Allen Paul R. Bradley Clare E. Challenger Michael Closier Tim J. Evans Mark L. Lewis John P. Mathias Carly L. Nichols Yvonne M. Po-Ba Hayley Snow Mark H. Stefaniak Hannah V. Vuong 《Tetrahedron》2006,62(29):6869-6875
The synthesis of ten substituted aminomethylene tetrahydro-isoquinolines is described, proceeding in eight steps from 5-hydroxyisoquinoline via reductive amination of N-Boc tetrahydro-isoquinoline 5-carboxaldehyde. Likewise, reductive amination was used to prepare four substituted dihydro-isoindoles from the corresponding aldehyde. The dihydro-isoindole ring system was conveniently accessed via a 2+2+2 cycloaddition reaction. 相似文献
29.
Woodward C. A. Macinnis J. M. Lewis S. N. Greenbaum E. 《Applied biochemistry and biotechnology》1992,34(1):819-826
Applied Biochemistry and Biotechnology - Normal photosynthesis byCyanidium results in O2 evolution, suggesting that the uptake and subsequent reduction of CO2 also occur. This process, therefore,... 相似文献
30.
Alan D. Potoff Bertrand L. Chamberland Lewis Katz 《Journal of solid state chemistry》1973,8(3):234-237
A single crystal study of hydrothermally prepared eight-layer BaMnO3 has been carried out which confirms the (Zhdanov notation) 121121 layer stacking scheme for the BaO3 layers. The MnO6 octahedra share faces in strings of four, and these strings are connected to each other by corner sharing. The compound has an hexagonal unit cell of dimensions a = 5.667 ± 0.003 and c = 18.738 ± 0.009 Å, probable space group . Its structure has been determined from 352 independent reflections, of which 242 were considered observed, collected manually by a counter technique and refined to a conventional R value of 0.079. 相似文献