Search results for "Reduct"

A singularly perturbed Kirchhoff problem revisited

2020

Abstract In this paper, we revisit the singularly perturbation problem (0.1) − ( ϵ 2 a + ϵ b ∫ R 3 | ∇ u | 2 ) Δ u + V ( x ) u = | u | p − 1 u in  R 3 , where a , b , ϵ > 0 , 1 p 5 are constants and V is a potential function. First we establish the uniqueness and nondegeneracy of positive solutions to the limiting Kirchhoff problem − ( a + b ∫ R 3 | ∇ u | 2 ) Δ u + u = | u | p − 1 u in  R 3 . Then, combining this nondegeneracy result and Lyapunov-Schmidt reduction method, we derive the existence of solutions to (0.1) for ϵ > 0 sufficiently small. Finally, we establish a local uniqueness result for such derived solutions using this nondegeneracy result and a type of local Pohozaev identity.

Impact of the erase algorithms on flash memory lifetime

2017

This paper presents a comparative study on the impact of the erase algorithm on flash memory lifetime, to demonstrate how the reduction of overall stress, suffered by memories, will increase their lifetime, thanks to a smart management of erase operations. To this purpose a fixed erase voltage, equal to the maximum value and the maximum time-window, was taken as the reference test; while an algorithm with adaptive voltage levels and the same overall time-window was designed and implemented in order to compare their experimental results. This study was carried out by using an innovative Automated Test Equipment, named Portable-ATE, tailored for Memory Test Chip and designed for performance e…

Low complexity digital background calibration algorithm for the correction of timing mismatch in time-interleaved ADCs

2019

Abstract A low-complexity post-processing algorithm to estimate and compensate for timing skew error in a four-channel time-interleaved analog to digital converter (TIADC) is presented in this paper, together with its hardware implementation. The Lagrange interpolator is used as the reconstruction filter which alleviates online interpolator redesign by using a simplified representation of coefficients. Simulation results show that the proposed algorithm can suppress error tones for input signal frequency from 0 to 0.4 f s . The proposed structure has, at least, 41% reduction in the number of required multipliers. Implementation of the algorithm, for a four-channel 10-bit TIADC, show that, f…

Optical study for springback prediction, thickness reduction and forces variations on single point incremental forming

2019

Abstract The goal of the present work is to present an experimental study regarding the influence of the main technological influence factors such as the vertical step and the punch diameter on the single point incremental forming process (SPIF). In this paper we estimate the influence of these two factors on springback, thickness reduction and forces. Both parameters were varied on two levels: (d) punch diameter 6 and 10 mm and (s) vertical step 0,1 and 0,5 mm. The experiments were done on experimental layout composed by a robot, a clamping system that contains the die’s lower part and the optical system.

Switching and redox isomerism in first-row transition metal complexes containing redox active Schiff base ligands.

2014

International audience; The reversible redox isomerisms in first row transition metal complexes of the type ML2 were studied. The six ML2 complexes (M = Mn(III) (), Fe(II) (), Co(III) (), Ni(II) (), Cu(II) () and Zn(II) ()) were synthesized with a redox active Schiff base ligand [2-(3,5-di-tert-butyl-2-hydroxyphenylamino)-4-chlorophenol] (H3L) presenting different oxidation states from -2 to 0 (L(2-), L(-) and L(0)). EPR spectra and magnetic susceptibility measurements indicate the presence of complexes of the type [Mn(III)(L(2-))(L(-))] () with S = 1/2, [Fe(II)(L(-))2] () with S = 2, [Co(III)(L(2-))(L(-))] () with S = 1/2, [Ni(II)(L(-))2] () with S = 1, [Cu(II)(L(-))2] () with S = 1/2 and …

Heavy enzymes and the rational redesign of protein catalysts

2019

Abstract An unsolved mystery in biology concerns the link between enzyme catalysis and protein motions. Comparison between isotopically labelled “heavy” dihydrofolate reductases and their natural‐abundance counterparts has suggested that the coupling of protein motions to the chemistry of the catalysed reaction is minimised in the case of hydride transfer. In alcohol dehydrogenases, unnatural, bulky substrates that induce additional electrostatic rearrangements of the active site enhance coupled motions. This finding could provide a new route to engineering enzymes with altered substrate specificity, because amino acid residues responsible for dynamic coupling with a given substrate present…

Exploring the Chemoselectivity towards Cysteine Arylation by Cyclometallated Au III Compounds: New Mechanistic Insights

2020

To gain more insight into the factors controlling the efficient cysteine arylation by cyclometalated Au(III) complexes, the reaction between selected gold compounds and different peptides was investigated by high‐resolution liquid chromatography electrospray ionization mass spectrometry (HR‐LC‐ESI‐MS). The deducted mechanisms of C–S cross‐coupling, also supported by density functional theory (DFT) and quantum mechanics/molecular mechanics (QM/MM) calculations, evidenced the key role of secondary peptidic gold binding sites in favouring the process of reductive elimination.

Lewis Base Catalyzed Intramolecular Reduction of Salicylaldehydes by Pinacol-Derived Chlorohydrosilane

2018

Catalytic activity of biscobalt porphyrin-corrole dyads toward the reduction of dioxygen

2009

A series of biscobalt cofacial porphyrin-corrole dyads bearing mesityl substituents at the meso positions of the corrole ring were investigated as to their electrochemistry, spectroelectrochemistry, and CO binding properties in nonaqueous media and then applied to the surface of a graphite electrode and tested as electrocatalysts for the reduction of dioxygen to water or hydrogen peroxide in air-saturated aqueous solutions containing 1 M HClO(4). The catalytic reduction of O(2) with the same dyads was also investigated in the homogeneous phase using 1,1'-dimethylferrocene as a reductant in PhCN containing HClO(4). The examined compounds are represented as (PMes(2)CY)Co(2), where P = a porph…

Optimized Class-Separability in Hyperspectral Images

2016

International audience; Image visualization techniques are mostly based on three bands as RGB color composite channels for human eye to characterize the scene. This, however, is not effective in case of hyper-spectral images (HSI) because they contain dozens of informative spectral bands. To eliminate redundancy of spectral information among these bands, dimensionality reduction (DR) is applied while at the same trying to retain maximum information. In this paper, we propose a new method of information-preserved hyper-spectral satellite image visualization that is based on fusion of unsupervised band selection techniques and color matching function (CMF) stretching. The results show consist…