Search results for "NICKEL"
showing 10 items of 1087 documents
Interactions of the alternating double stranded copolymer poly(dA-dT).poly(dA-dT) with NiCl2 and CdCl2: solution behaviour
2007
The thermal denaturation of the synthetic high molecular weight double stranded polynucleotide poly(dA-dT) x poly(dA-dT) has been studied in aqueous buffered solution (Tris 1.0 mM; pH 7.8+/-0.2) in the presence of increasing concentrations of either Ni(2+) (borderline cation) or Cd(2+) (soft cation) at four different constant ionic strength values (NaCl), making use of UV and circular dichroism (CD) spectroscopies. The experimental results show that the B-type double helix of the polymer is stabilized against thermal denaturation in the presence of both cations at low concentrations, relative to the systems where only NaCl is present, in the same conditions of ionic strength and pH. The eff…
Highly selective recovery of Ni(II) in neutral and acidic media using a novel Ni(II)-ion imprinted polymer
2022
In this work, an original ion-imprinted polymer (IIP) was synthetized for the highly selective removal of Ni(II) ions in neutral and acidic media. First a novel functional monomer (AMP-MMA) was synthetized through the amidation of 2-(aminomethyl)pyridine (AMP) with methacryloylchloride. Following Ni(II)/AMP-MMA complex formation study, the Ni(II)-IIP was produced via inverse suspension polymerization (DMSO in mineral oil) and characterized with solid state 13C CPMAS NMR, FT-IR, SEM and nitrogen adsorption/desorption experiments. The Ni(II)-IIP was then used in solid-phase extraction of Ni(II) exploring a wide range of pH (from neutral to strongly acidic solution), several initial concentrat…
Experimental characterization of micromechanical and microphological properties of nickel base alloys strained by the growth of an ovide payer made i…
2011
The loss of the corrosion resistance of the alloy 600, a nickel base alloy, during the oxidation in pressurized water reactor (PWR) has been demonstrated by many studies. It induces the intergranular stress corrosion cracking (IGSCC). If the chemical composition and the structure of the growing oxide are well-known, the mechanical influence of the oxide on the alloy has not been fully studied, yet. This study aims at bringing new knowledge of the oxidation impact on the mechanical response of the alloy. A new methodology is introduced for determining the local nanodeformation of the alloy 600 induced either by an oxidation or by a tensile loading. This method is based on nanodots disposed a…
The efficacy of two rotary NiTi instruments and H-files to remove gutta-percha from root canals
2011
WOS: 000304343300026
A variable charge molecular dynamics study of the initial stage of nickel oxidation
2010
Abstract The oxidation of nickel single crystals is investigated by using variable charge molecular dynamics. The simulations are performed on three nickel low-index surfaces ((1 0 0), (1 1 0) and (1 1 1)) at temperatures between 300 K and 950 K. The results show that the shape of the oxidation kinetics is independent of the crystallographic orientation and the temperature under the present conditions. The oxide thin film grows according to an island growth mode, this initial stage of oxidation can be divided in three steps: (i) the dissociative chemisorption step (ii) the oxide island nucleation and (iii) the lateral growth of the island. The first step is slowdown/speedup by the surface o…
Precipitation and Calcination of High-Capacity LiNiO2 Cathode Material for Lithium-Ion Batteries
2020
This article presents the electrochemical results that can be achieved for pure LiNiO2 cathode material prepared with a simple, low-cost, and efficient process. The results clarify the roles of the process parameters, precipitation temperature, and lithiation temperature in the performance of high-quality LiNiO2 cathode material. Ni(OH)2 with a spherical morphology was precipitated at different temperatures and mixed with LiOH to synthesize the LiNiO2 cathode material. The LiNiO2 calcination temperature was optimized to achieve a high initial discharge capacity of 231.7 mAh/g (0.1 C/2.6 V) with a first cycle efficiency of 91.3% and retaining a capacity of 135 mAh/g after 400 cycles. These a…
Correlation of aluminum doping and lithiation temperature with electrochemical performance of LiNi1-xAlxO2 cathode material
2022
Abstract This article presents a process for producing LiNi1-xAlxO2 (0 < × < 0.05) cathode material with high capacity and enhanced cycle properties of 145 mAh/g after 600 cycles. The LiNi1-xAlxO2 (0 < × < 0.05) cathode material is prepared by mixing coprecipitated Ni(OH)2 with LiOH and Al(OH)3, followed by lithiation at temperature range of 650–710 °C, after which any residual lithium from lithiation is washed from the particle surfaces. Electrochemical performance was studied within full-cell and half-cell application; in addition, different material characterization methods were carried out to explain structure changes when certain amount of aluminum is introduced in the …
Effect of EDTA on divalent metal adsorption onto grape stalk and exhausted coffee wastes
2007
In the present work, two industrial vegetable wastes, grape stalk, coming from a wine producer, and exhausted coffee, coming from a soluble coffee manufacturer, have been investigated for the removal of Cu(II) and Ni(II) from aqueous solutions in presence and in absence of the strongly complexing agent EDTA. Effects of pH and metal-EDTA molar ratio, kinetics as a function of sorbent concentration, and sorption equilibrium for both metals onto both sorbents were evaluated in batch experiments. Metal uptake was dependent of pH, reaching a maximum from pH around 5.5. EDTA was found to dramatically reduce metal adsorption, reaching total uptake inhibition for both metals onto both sorbents at e…
Heterobimetallicd—f Metal Complexes as Potential Single-Source Precursors for MOCVD: Structure and Thermodynamic Study of the Sublimation of [Ni(sale…
1998
Heterobimetallic [Ni(salen)Ln(hfa)3] species [H2salen and Hhfa being N,N′-ethylenebis(salicylideneimine) and hexa-fluoroacetylacetone respectively], where Ni(salen) acts as a neutral chelating ligand towards LnIII, form a series of isostructural compounds for Ln = YIII and any lanthanideIII cation from La to Yb. They are also isostructural with some of the [Cu(salen)Ln(hfa)3] compounds. They sublime without decomposition under vacuum which makes them potential single-source precursors in MOCVD. Sublimation, thermal behaviour, pressure and composition of the vapour phase versus temperature have been studied for the yttrium derivative, by means of thermal analyses, and mass spectrometry using…
Magnon and Phonon Excitations in Nanosized NiO
2019
Single-crystal, microcrystalline and nanocrystalline nickel oxides (NiO) have been studied by Raman spectroscopy. A new band at ~200 cm-1 and TO-LO splitting of the band at 350–650 cm-1 have been found in the spectra of single-crystals NiO(100), NiO(110) and NiO(111). The Raman spectra of microcrystalline (1500 nm) and nanocrystalline (13–100 nm) NiO resemble those of the single crystals. They all contain the two-magnon band at 1500 cm-1, indicating that the oxides remain at room temperature in the antiferromagnetic phase. Besides, a new sharp Raman band has been observed at 500 cm-1 in nanocrystalline NiO. Its temperature dependence suggests the magnetic origin of the band, possibly associ…