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Optimization of the Heck reaction of 4-bromoacetophenone with styrene by a polymer supported, sulfur-containing palladacycle, varying 6 factors at a total of 28 different levels, corresponding to 5760 different possibilities was undertaken. Conversion improved from 34%, with large observable leaching to 88% with no leaching. This was accomplished using a Design of Experiments approach facilitated by the Statistical Design Package, MODDE 7.0TM. 相似文献
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Catherine Cordier-Robert Thierry Grosdidier Gang Ji Jacques Foct 《Hyperfine Interactions》2006,168(1-3):951-957
Microstructured (atomized) and nanostructured (milled) Fe60Al40 powders together with their corresponding coatings synthesized by High Velocity Oxy-fuel (HVOF) or Atmospheric Plasma Spray (APS) thermal spraying techniques have been characterized by Mössbauer Spectroscopy (MS) and X-ray Diffraction (XRD). The evolution of the microstructure and the atomic ordering degree in the powders and coatings are discussed at the light of the various processing conditions. The operational correlation between the parameters of the duplex morphology of coatings and the processing parameters is discussed. 相似文献
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A. Craig W. H. Jacobson A. Meyer N. Welwart A. Seuthe H. N. Marr B. S. Evans G. E. F. Lundell J. A. Scherrer E. Stelling F. J. Mück A. Kling A. Lassieur L. Bertiaux C. C. Bissett P. de Pauw J. Heslinga A. Bartsch R. E. Lee W. H. Fegeley F. H. Reichel und E. Saz 《Fresenius' Journal of Analytical Chemistry》1927,71(1-2):83-90
Ohne Zusammenfassung 相似文献
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We close a gap in the proof of Theorem 4.1 in our paper “The complexity of counting graph homomorphisms” [Random Structures Algorithms 17 (2000), 260–289]. © 2004 Wiley Periodicals, Inc. Random Struct. Alg., 2004 相似文献
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The Planar Laser-Induced Fluorescence (PLIF) technique enables measurement of the local degree of deviation in an arbitrary
plane inside the mixing vessel. This is achieved by injecting a mixture of an inert dye and a reacting fluorescent into the
vessel. The inert dye serves as a tracer for the macromixing. The fluorescent characteristics of the reacting dye change while
undergoing a fast chemical reaction with the vessel content and it therefore shows the micromixing indirectly. The concentration
fields of the dyes are measured simultaneously. For that a laser beam is expanded into a thin light sheet which illuminates
an arbitrary plane in the mixing vessel, exciting the fluorescent dye in this area. The emitted light is detected by a CCD-camera
which is positioned vertical to the measurement plane. The fluorescent light passes through two optical filters which are
suitable for separating the fluorescent light of the two dyes. The light is then projected on half of the camera chip each
so that the same display window is detected twice, and thus the local concentration of the two dyes can be measured simultaneously.
Low Reynolds number measurements are performed in a mixing vessel equipped with a Rushton turbine. The lamellar structure
is clearly resolved. Areas of micromixing are detected by calculating the local degree of deviation from the concentration
fields. These areas are mainly found in the boundary layer of the lamellas. 相似文献
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All-electron full-potential linearized augmented plane-wave calculations of the surface energy, work function, and interlayer spacings of close-packed metal surfaces are presented, in particular, for the free-electron-like metal surfaces, Mg(0 0 0 1) and Al(1 1 1), and for the transition metal surfaces, Ti(0 0 0 1), Cu(1 1 1), Pd(1 1 1), and Pt(1 1 1). We investigate the convergence of the surface energy as a function of the number of layers in the slab, using the Cu(1 1 1) surface as an example. The results show that the surface energy, as obtained using total energies of the slab and bulk from separate calculations, converges well with respect to the number of layers in the slab. Obviously, it is necessary that bulk and surface calculations are performed with the same high accuracy. Furthermore, we discuss the performance of the local-density and generalized gradient approximations for the exchange-correlation functional in describing the various surface properties. 相似文献