Search results for " Rat"
showing 10 items of 9334 documents
Experimental comparison of two control algorithms for low-saliency ratio interior permanent magnet synchronous motors
2018
In this paper, an experimental investigation on the comparison between the Maximum Torque Per Ampere (MTPA) and the Field Orientation Control (FOC) algorithms for interior permanent magnet synchronous machines (IPMSMs) is described, analyzed and discussed. This investigation was carried out on a small-power IPMSM with low saliency ratio. More in detail, after a previous simulation study, the control techniques have been experimentally implemented and validated through means of a dSPACE® rapid prototyping system. The performances of the two algorithms have been evaluated and compared, obtaining interesting results.
Deposition of binder-free oxygen-vacancies NiCo2O4 based films with hollow microspheres via solution precursor thermal spray for supercapacitors
2019
Abstract Hollow micro-/nanostructures and oxygen vacancies are highly desirable for supercapacitors due to high active surface area and outstanding electrochemical properties. In order to benefiting from the both effect, binder-free oxygen-vacancies NiCo2O4 based films with hollow microspheres were pioneering directly deposited via one kind thermal spray technology, named solution precursor thermal spray (SPTS) process. To our best knowledge, the rapid one-step SPTS route was firstly employed to synthesize and deposit NiCo2O4 films for supercapacitor applications. The CV data clearly demonstrated that the specific capacitances of more oxygen-deficient NiCo2O4 electrodes with hollow microsph…
Estimating ion confinement times from beam current transients in conventional and charge breeder ECRIS
2019
International audience; Cumulative ion confinement times are probed by measuring decaying ion current transients in pulsed material injection mode. The method is applied in a charge breeder and conventional ECRIS yielding mutually corroborative results. The cumulative confinement time estimates vary from approximately 2 ms–60 ms with a clear dependence on the ion charge-to-mass ratio—higher charges having longer residence times. The long cumulative confinement times are proposed as a partial explanation to recently observed unexpectedly high ion temperatures. The results are relevant for rare ion beam (RIB) production as the confinement time and the lifetime of stable isotopes can be used f…
Quantum dynamics of 16O in collision with ortho- and para-17O17O
2017
Abstract We report full quantum dynamical observables, such as integral and differential cross sections and rate constants, for the 16 O + 17 O 17 O reactive collision process. We particularly emphasize the effect coming from the nonzero nuclear spin of 17 O, leading to two nuclear spin isomers of 34 O 2 , ortho- and para- 34 O 2 which can be studied independently and behave differently. A comparison with the 16 O + 18 O 18 O collision is given. We find that processes involving 17 O 17 O are always faster than with 18 O 18 O.
Unravelling the kinetics and molecular mechanism of the degenerate Cope rearrangement of bullvalene
2020
The kinetics and molecular mechanism of the gas phase degenerate Cope rearrangement (DCR) of bullvalene have been investigated by applying quantum mechanical calculations. Highly accurate energies (CBS-QB3 and CBS-APNO) and RRKM calculations were employed to study the kinetics and ‘fall-off’ behavior. It was found that the DCR of bullvalene (C3v) occurs through a bishomoaromatic transition structure (C2v) with an energy barrier of ∼49 kJ mol−1. The calculated activation energy and enthalpy were in good agreement with the available values in the literature, but lower than those of common Cope rearrangement; this result is related to the high stabilization energy due to the interaction of the…
Quantum Dynamics of the 17O + 32O2 Collision Process
2016
We report full quantum integral and differential cross sections and rate constants for the 17O + 32O2 reactive process. This constitutes the first quantum scattering study of the 17O16O16O system. We emphasize the comparison with the 18O + 32O2 collision in close connection to the mass-independent fractionation (hereafter referred to as MIF) puzzle for ozone in atmospheric chemistry. We find similar general trends in the cross sections and rate constants for both rare isotopes, but we note some singular behaviors peculiar to the use of 17O isotope, particularly at the lowest collision energies.
Elucidating the Influence of the Activation Energy on Reaction Rates by Simulations Based on a Simple Particle Model
2020
An application for visualizing the dynamic properties of an equimolar binary mixture of isotropic reactive particles is presented. By introducing a user selectable choice for the activation energy, the application is useful to demonstrate qualitatively that the reaction rate depends on the above choice and on temperature. The application is based on a 2D realistic dynamic model where atoms move because of their thermal energies and the trajectories are determined by solving numerically Newton’s laws according to a Molecular Dynamics (MD) scheme. Collisions are monitored as time progresses, and every time the collision energy is larger than the selected activation energy, a reactive event oc…
Localization of alkali metal ions in sodium-promoted palladium catalysts as studied by low energy ion scattering and transmission electron microscopy
1996
Three series of palladium-based catalysts have been studied by Low Energy Ion Scattering (LEIS) and Transmission Electron Microscopy (TEM). The first series is comprised of Na-Pd/SiO{sub 2} catalysts, obtained by addition of palladium to a silica support and by further addition of sodium ions with a Na/Pd atomic ratio (R) equal to 0,6.4 and 25.6. The second series consists of palladium catalysts supported on natural pumice, in which, due to a different loading of supported palladium, R{prime}, the (Na+K)/Pd atomic ratio, is equal to 17.0 and 39.4. The third series is represented by two palladium-based catalysts supported on {open_quotes}model pumices,{close_quotes} synthetic silico-aluminat…
Synthesis of substituted piperidines by enantioselective desymmetrizing intramolecular aza-Michael reactions.
2018
An organocatalytic enantioselective intramolecular aza-Michael reaction has been described for the first time in a desymmetrization process employing substrates different from cyclohexadienones. By using 9-amino-9-deoxy-epi-hydroquinine as the catalyst and trifluoroacetic acid as a co-catalyst, a series of enantiomerically enriched 2,5-and 2,6-disubstituted piperidines have been obtained in good yields and with moderate diastereoselectivity. Depending on the catalyst/co-catalyst loading ratio, either the major or the minor diastereoisomer of the final piperidine products was achieved with high levels of enantioselectivity. Finally, some mechanistic insights have been considered by means of …
Mononuclear Rearrangement of the Z-Phenylhydrazones of Some 3-Acyl-1,2,4-oxadiazoles: Effect of Substituents on the Nucleophilic Character of the >…
2019
The reaction rates for the mononuclear rearrangement of the Z-phenylhydrazones of 3-acyl-1,2,4-oxadiazoles 3a-c into the relevant 2-phenyl-2 H-1,2,3-triazoles (4a-c) have been measured in dioxane/water at different temperatures in a large range of proton concentrations. The occurrence of two different reaction pathways (one uncatalyzed, water assisted, and the other general base catalyzed) has- been observed. The obtained results have been able to furnish information about the effects of the nature of the 3-acyl structure and of the 5-substituents in the 1,2,4-oxadiazole ring on the reactivity of the examined rearrangements: they are well in line with the previsions carried out considering …