X-ray standing waves and scanning electron microscopy — Energy dispersive X-ray emission spectroscopy study of gold nanoparticles

A systematic characterization of mono-disperse nanoparticles with nominal diameters of 25 nm, 46 nm, 73 nm, 100 nm, 115 nm, and 250 nm was performed using X-ray standing waves (XSW). The samples were prepared on Si-wafer pieces and analyzed at DELTA synchrotron facility at beamline BL8 under grazing incidence geometry of the primary radiation. Additionally, SEM-EDX inspections of single particles as well as population-density checks were conducted. Particles with smaller diameters were able be characterized by XSW while the larger ones were not completely covered by the interference field produced by the provided 15 keV monochromatic radiation of BL8. The results of the measurements were compared with those of numerical simulations. The extension of the interference field perpendicular to the Si-wafer reflector was determined to be 83 nm ± 4 nm.     

New Maximal Numbers of Equilibria in Bimatrix Games

This paper presents a new lower bound of on the maximal number of Nash equilibria in d×d bimatrix games, a central concept in game theory. The proof uses an equivalent formulation of the problem in terms of pairs of polytopes with 2d facets in d -space. It refutes a recent conjecture that 2 ^d -1 is an upper bound, which was proved for d≤4. The first counterexample is a 6×6 game with 75 equilibria. The case d=5 remains open. The result carries the lower bound closer to the previously known upper bound of . Received July 23, 1997, and in revised form June 26, 1998.     

The dynamics of brand equity: a hedonic regression approach to the laser printer market

The authors develop a dynamic hedonic regression approach to measuring the evolution of a comparative brand premium (pairwise price difference between two products that are identical in all respects apart from the brand). In contrast to existing approaches, the proposed Bayesian estimation method exploits the premia's intertemporal dependence structure, resulting in a higher level of accuracy of the estimated time paths of the brand premia. In addition, the authors present a novel, but straightforward way to construct confidence bands that cover the entire time series of brand premia with high probability. The authors apply their approach to a large, detailed data set on laser printers, which was gathered on a monthly basis over a 4-year period.     

Solid-phase synthesis of 2,3,4,5-tetrahydro-1H-benzo[e][1,4]diazepine derivatives

We have developed an efficient solid-phase synthetic approach for the synthesis of 2,3,4,5-tetrahydro-1H-benzo[e][1,4]diazepine derivatives. The methodology is of value for high throughput synthesis of these potentially bioactive molecules.     

GPU computing for shallow water flow simulation based on finite volume schemes

This article is a review of the work that we are carrying out to efficiently simulate shallow water flows. In this paper, we focus on the efficient implementation of path-conservative Roe type high-order finite volume schemes to simulate shallow flows that are supposed to be governed by the one-layer or two-layer shallow water systems, formulated under the form of a conservation law with source terms. The implementation of the scheme is carried out on Graphics Processing Units (GPUs), thus achieving a substantial improvement of the speedup with respect to normal CPUs. Finally, some numerical experiments are presented.     

Cluster and Molecular Mechanical Analysis of Cobalt(III) 14-Membered Macrocyclic Complexes

The configurational distribution of all the cobalt(III) complexes containing a 14-membered tetra-aza macrocyclic backbone in the Cambridge Structural Database was determined by cluster analysis, and the reason for some of the complexes adopting their configuration was established by molecular mechanics.