Search results for " transition"

Nitrogen-Doped Carbon Nanodots-Ionogels: Preparation, Characterization, and Radical Scavenging Activity

2018

Hybrid diimidazolium-based ionogels were obtained by dispersing nitrogen-doped carbon nanodots (NCNDs) in ionic liquid (IL) solutions and by using dicationic organic salts as gelators. The properties of the NCND-ionogels were studied in terms of thermal stability, mechanical strength, morphology, rheological, and microscopic analyses. Insights into the formation of the hybrid soft material were attained from kinetics of sol-gel phase transition and from estimating the size of the aggregates, obtained from opacity and resonance light-scattering measurements. We demonstrate that, on one hand, NCNDs were able to favor the gel formation both in the presence of gelating and nongelating ILs. On t…

Architecture and dynamics of a Maghrebian carbonate platform-basin transition around the Triassic/Jurassic Boundary: Sciacca zone, Sicily.

2007

Promuovere le character skills per la transizione scuola-università: una ricerca- intervento internazionale

2022

In this contribution, we want to describe methodological assumptions with which to promote some character skills that must be trained in the students attending high school in view of the transition from school to university. These abilities are related to the person’s character, emotional and psychosocial aspects of the personality like flexibility, creativity, open-mindedness, resilience, decision-making skill and self-image. These skills significantly contribute to the construction of the 16-18-year-old student’s identity and support the development of his professional maturity during the school education period. High school teachers can contribute to this development by applying didactic…

Una ricerca-intervento internazionale per costruire al liceo il proprio progetto di vita professionale

2022

In this contribution, we want to describe methodological assumptions with which to promote some character skills that must be trained in the students attending high school in view of the transition from school to university. These abilities are related to the person’s character, emotional and psychosocial aspects of the personality like flexibility, creativity, open-mindedness, resilience, decision-making skill and self-image. These skills significantly contribute to the construction of the 16-18-year-old student’s identity and support the development of his professional maturity during the school education period. High school teachers can contribute to this development by applying didactic…

Field-induced slow relaxation of magnetization in a mononuclear Co(II) complex of 2,6-bis(pyrazol-1-yl)pyridine functionalized with a carboxylic acid

2018

Abstract Combining Co(II) with the 2,6-bis-(pyrazol1-yl)pyridine ligand functionalized with a carboxylic acid group (bppCOOH) results in the compound [CoII(bppCOOH)2](ClO4)2·2Me2CO, which shows a field-induced slow relaxation of magnetization as a result of the magnetic anisotropy of the distorted octahedral coordination of high-spin Co(II). Co(II)/Fe(II) solid solutions of bppCOOH have been prepared to study the influence of Co(II) on the spin crossover properties of Fe(II). Magnetic characterization of [Fe0.92Co0.08(bppCOOH)2](ClO4)2 indicates that the Cobalt dopant leads to a reduction of T1/2 and a loss of cooperativity of the spin transition.

Magnetic phase transition and magnetic bistability in oxamato-based CoIICuII bimetallic MOF thin films

2019

Abstract Thin films of an anionic oxamato-bridged cobalt(II)–copper(II) 3D MOF have been growth at 120 °C in DMSO through a one-pot reaction from Co(NO3)2·6H2O and (Me4N)2[Cu(2,6-Et2pa)2]·6H2O (2,6-Et2pa = N-2,6-diethylphenyloxamate) over Si(111) surfaces functionalized with carboxylic acid terminating groups. These heterobimetallic CoII2CuII3 MOF thin films (2) of about ten nanometers thickness show a ferrimagnetically ordered phase below ca. 10 K with a relatively large magnetic hysteresis similar to that of the bulk material of formula (Me4N)2[Co2Cu3(2,6-Et2pa)6]·5H2O (1).

Spin-crossover compounds based on iron(II) complexes of 2,6-bis(pyrazol-1-yl)pyridine (bpp) functionalized with carboxylic acid and ethyl carboxylic …

2018

International audience; Four new salts of the iron(II) complex of the 2,6-bis(pyrazol-1-yl)pyridine ligand functionalized with a carboxylic acid group (bppCOOH) of formulas [Fe(bppCOOH)2](BF4)2 (1(BF4)2), [Fe(bppCOOH)2](CF3SO3)2·yMe2CO (1(CF3SO3)2·yMe2CO), [Fe(bppCOOH)2](AsF6)2·yMe2CO (1(AsF6)2·yMe2CO) and [Fe(bppCOOH)2](SbF6)2·yMe2CO (1(SbF6)2·yMe2CO) have been prepared and characterized together with a more complete structural and photomagnetic characterization of the previously reported [Fe(bppCOOH)2](ClO4)2 (1(ClO4)2). Furthermore, the iron(II) complex of the ethyl ester derivative of bppCOOH (bppCOOEt) has been prepared and characterized (compound [Fe(bppCOOEt)2](ClO4)2·yMe2CO, 2(ClO4)…

The First 1,3,4‐Oxadiazole Based Dinuclear Iron(II) Complexes Showing Spin Crossover Behavior with Hysteresis

2015

Three new dinuclear complexes [FeII2(μ-L)2]X4 (L is the bis-tridentate ligand 2,5-bis{[(2-pyridylmethyl)amino]methyl}-1,3,4-oxadiazole and X = ClO4–, BF4– and CF3SO3–) have been synthesized and fully characterized by single-crystal X-ray diffraction, Mossbauer spectroscopy and magnetic susceptibility measurements. Upon cooling, a trapped [high-spin–low-spin] state of the iron(II) centres is detected. Depending on the counterion, a pronounced thermal hysteresis is found. In one case, it was possible to observe a space group change that accompanies the spin transition. This is the first system showing spin crossover based on an oxadiazole ligand.

Hydrothermally resistant thermally reduced graphene oxide and multi-wall carbon nanotube based epoxy nanocomposites

2013

This study is focused on the investigation of thermo-mechanical properties of an epoxy resin filled with thermally reduced graphene oxide (TRGO) and multi-wall carbon nanotubes (MWCNT) after exposure of samples to hot distilled water. Addition of low contents of TRGO and MWCNTs greatly reduces the water sorption capacity of the epoxy polymer and improves its resistance to hydrothermal ageing. The glassy and rubbery moduli of the neat epoxy decreased for about 20% and 80%, respectively, while TRGO-based epoxy filled with 0.3 wt.% of TRGO showed only 6% reduction of both moduli. Hydrothermal ageing resulted in an enormous drop in the glass transition temperature (Tg) of the neat epoxy, by abo…

On the Glass Transition in Polymer Films: Recent Monte Carlo Results

1998

AbstractThis paper reports results of a Monte Carlo simulation for a simplified lattice modelof a supercooled polymer film. The film geometry is realized by two opposite hard walls.The distance between the walls is varied. The chains exhibit a strong tendency to orientparallel to the walls and are flattened when being very close to them. This deviation of thepolymer structure with respect to the bulk is accompanied by an acceleration of local densityfluctuations. On the other hand, the diffusion coefficient of a chain remains unaffected.