MASSIS: a mass spectrum simulation system 1. Principle and method

A mass spectrum simulation system was developed. The simulated spectrum for a given target structure is computed based on the cleavage knowledge and statistical rules established and stocked in pivot databases: cleavage rule knowledge, function groups, small fragments and fragment-intensity relationships. These databases were constructed from correlation charts and statistical analysis of large population of organic mass spectra using data mining techniques. Since 1980, several systems were proposed for mass spectrum simulation, but in present there is no any commercial software available. This shows the complexity and difficulties in the development of a such system. The reported mass spectral simulation system in this paper could be the first general software for organic chemistry use     

Characterisation of Ba2In2 − x Sn x O5 + x/2 oxide ion conductors

The Ba₂In_2 − x Sn _x O_5 + x/2 solid solution was confirmed up to x = 1 by solid-state reaction. X-ray diffraction at room and at elevated temperatures, Raman scattering and impedance spectroscopy were used to characterise the samples. The structure refinement of the composition x = 0.1 from neutron diffraction data reveals that tin is preferentially located in the tetrahedral layers of the brownmillerite. Paper presented at the 11th EuroConference on the Science and Technology of Ionics, Batz-sur-Mer, Sept. 9–15, 2007     

Potential,value, and coalition formation

In this paper, a simple probabilistic model of coalition formation provides a unified interpretation for several extensions of the Shapley value. Weighted Shapley values, semivalues, weak (weighted or not) semivalues, and the Shapley value itself appear as variations of this model. Moreover, some notions that have been introduced in the search of alternatives to Shapley’s seminal characterization, as ‘balanced contributions’ and the ‘potential’ are reinterpreted from this point of view. Natural relationships of these conditions with some mentioned families of ‘values’ are shown. These reinterpretations strongly suggest that these conditions are more naturally interpreted in terms of coalition formation than in terms of the classical notion of ‘value.’      

Sensitivity of trust-region algorithms to their parameters

In this paper, we examine the sensitivity of trust-region algorithms on the parameters related to the step acceptance and update of the trust region. We show, in the context of unconstrained programming, that the numerical efficiency of these algorithms can easily be improved by choosing appropriate parameters. Recommended ranges of values for these parameters are exhibited on the basis of extensive numerical tests. MSC classification: 65K05, 90C26, 90C30     

On the Second Law of Thermodynamics and the Piston Problem

The piston problem is investigated in the case where the length of the cylinder is infinite (on both sides) and the ratio m/M is a very small parameter, where m is the mass of one particle of the gaz and M is the mass of the piston. Introducing initial conditions such that the stochastic motion of the piston remains in the average at the origin (no drift), it is shown that the time evolution of the fluids, analytically derived from Liouville equation in a previous work, agrees with the Second Law of thermodynamics. We thus have a non equilibrium microscopical model whose evolution can be explicitly shown to obey the two laws of thermodynamics.     

Relevant synthesis parameters for the sequential catalytic growth of carbon nanotubes

Sequential catalytic growth provides an efficient tool for the synthesis of carbon nanotubes periodically inserted with catalyst nanoparticles. Several synthesis parameters were found crucial in order to induce this particular growth mechanism. The presence of phosphorus is required to form metal phosphide particles active for the formation of carbon nanotubes with a matchstick morphology. The metal composition (Ni/Fe ratio) and the carbon supply have no influence on the nanofilament type but strongly affect the nanotube yield. The synthesis temperature induces important changes on both the nanofilament type and yield, which are correlated with important transformations of the catalyst layer in terms of composition, particle size, and physical state.