Search results for "LEAN"
showing 10 items of 3611 documents
Investigation of the SHS mechanisms of titanium nitride by in situ time-resolved diffraction and infrared thermography
2007
Abstract The self-propagating high-temperature synthesis (SHS) or combustion synthesis is a promising process to produce advanced ceramics due to the high purity of the elaborated materials and the very short synthesis time. Titanium nitride has been synthesised from pressed titanium powder and a nitrogen gas flow under a 0.1 MPa pressure. The influence of the addition of a TiN diluent was investigated. For the first time, SHS reaction mechanisms were determined from in situ time-resolved X-ray diffraction (TRXRD) experiments using the synchrotron radiation. These experiments were coupled with infrared thermography to study the propagation of the combustion reaction. It appeared that the in…
Implementation of single-qubit quantum gates by adiabatic passage and static laser phases
2006
International audience; We propose and analyse experimentally feasible implementations of single-qubit quantum gates based on stimulated Raman adiabatic passage (STIRAP) between magnetic sublevels in atoms coupled by elliptically polarized pulsed laser fields, in part based on a proposal by Kis and Renzoni [Z. Kis, F. Renzoni, Phys. Rev. A 65 (2002) 032318]. These techniques require only the control of the relative phase of the driving fields but do not involve any dynamical or geometric phases, which makes it independent of the other interaction details: detuning, pulse shapes, pulse areas and pulse durations. The suggested techniques are immune to spontaneous emission since the qubit mani…
Multicatalytic Transformation of (Meth)acrylic Acids: a One-Pot Approach to Biobased Poly(meth)acrylates
2021
International audience; Shifting from petrochemical feedstocks to renewable resources can address some of the environmental issues associated with petrochemical extraction and make plastics production sustainable. Therefore, there is a growing interest in selective methods for transforming abundant renewable feedstocks into monomers suitable for polymer production. Reported herein are one-pot catalytic systems, that are active,<br>productive, and selective under mild conditions for the synthesis of copolymers from renewable materials. Each system allows for anhydride formation, alcohol acylation and/or acid esterification, as well as polymerization of the formed (meth)- acrylates, providi…
Gelled Electrolyte Containing Phosphonium Ionic Liquids for Lithium-Ion Batteries
2018
In this work, new gelled electrolytes were prepared based on a mixture containing phosphonium ionic liquid (IL) composed of trihexyl(tetradecyl)phosphonium cation combined with bis(trifluoromethane)sulfonimide [TFSI] counter anions and lithium salt, confined in a host network made from an epoxy prepolymer and amine hardener. We have demonstrated that the addition of electrolyte plays a key role on the kinetics of polymerization but also on the final properties of epoxy networks, especially thermal, thermo-mechanical, transport, and electrochemical properties. Thus, polymer electrolytes with excellent thermal stability (>
Some Computational Aspects of DISTANCE-SAT
2007
In many AI fields, one must face the problem of finding a solution that is as close as possible to a given configuration. This paper addresses this problem in a propositional framework. We introduce the decision problem distance-sat, which consists in determining whether a propositional formula admits a model that disagrees with a given partial interpretation on at most d variables. The complexity of distance-sat and of several restrictions of it are identified. Two algorithms based on the well-known Davis/Logemann/Loveland search procedure for the satisfiability problem sat are presented so as to solve distance-sat for CNF formulas. Their computational behaviors are compared with the ones …
Limits on a muon flux from Kaluza-Klein dark matter annihilations in the Sun from the IceCube 22-string detector
2010
A search for muon neutrinos from Kaluza-Klein dark matter annihilations in the Sun has been performed with the 22-string configuration of the IceCube neutrino detector using data collected in 104.3 days of live-time in 2007. No excess over the expected atmospheric background has been observed. Upper limits have been obtained on the annihilation rate of captured lightest Kaluza-Klein particle (LKP) WIMPs in the Sun and converted to limits on the LKP-proton cross-sections for LKP masses in the range 250 -- 3000 GeV. These results are the most stringent limits to date on LKP annihilation in the Sun.
Muons in air showers at the Pierre Auger Observatory
2015
We present the first hybrid measurement of the average muon number in air showers at ultrahigh energies, initiated by cosmic rays with zenith angles between 62° and 80°. The measurement is based on 174 hybrid events recorded simultaneously with the surface detector array and the fluorescence detector of the Pierre Auger Observatory. The muon number for each shower is derived by scaling a simulated reference profile of the lateral muon density distribution at the ground until it fits the data. A 1019eV shower with a zenith angle of 67°, which arrives at the surface detector array at an altitude of 1450 m above sea level, contains on average (2.68±0.04±0.48(sys))×107 muons with energies large…
Physics at a future Neutrino Factory and super-beam facility
2009
The conclusions of the Physics Working Group of the international scoping study of a future Neutrino Factory and super-beam facility (the ISS) are presented. The ISS was carried by the international community between NuFact05, (the 7th International Workshop on Neutrino Factories and Superbeams, Laboratori Nazionali di Frascati, Rome, June 21-26, 2005) and NuFact06 (Ivine, California, 24{30 August 2006). The physics case for an extensive experimental programme to understand the properties of the neutrino is presented and the role of high-precision measurements of neutrino oscillations within this programme is discussed in detail. The performance of second generation super-beam experiments, …
Upper limit on the cosmic-ray photon fraction at EeV energies from the Pierre Auger Observatory
2009
From direct observations of the longitudinal development of ultra-high energy air showers performed with the Pierre Auger Observatory, upper limits of 3.8%, 2.4%, 3.5% and 11.7% (at 95% c.l.) are obtained on the fraction of cosmic-ray photons above 2, 3, 5 and 10 EeV (1 EeV equivalent to 10(18) eV), respectively. These are the first experimental limits on ultra-high energy photons at energies below 10 EeV. The results complement previous constraints on top-down models from array data and they reduce systematic uncertainties in the interpretation of shower data in terms of primary flux, nuclear composition and proton-air cross-section.
The Lateral Trigger Probability function for the Ultra-High Energy Cosmic Ray Showers detected by the Pierre Auger Observatory
2011
In this paper we introduce the concept of Lateral Trigger Probability (LTP) function, i.e., the probability for an Extensive Air Shower (EAS) to trigger an individual detector of a ground based array as a function of distance to the shower axis, taking into account energy, mass and direction of the primary cosmic ray. We apply this concept to the surface array of the Pierre Auger Observatory consisting of a 1.5 km spaced grid of about 1600 water Cherenkov stations. Using Monte Carlo simulations of ultra-high energy showers the LTP functions are derived for energies in the range between 1017 and 1019 eV and zenith angles up to 65. A parametrization combining a step function with an exponenti…