Optimization of hydrophilic/hydrophobic phase separation in sPEEK membranes by hydrothermal treatments

2017 ◽  
Vol 19 (24) ◽  
pp. 16013-16022 ◽  
Author(s):  
H. Mendil-Jakani ◽  
I. Zamanillo López ◽  
V. H. Mareau ◽  
L. Gonon
Keyword(s):  
Phase Separation ◽  
Swelling Behavior ◽  
Thermally Activated ◽  
Β Relaxation ◽  
Thermally Activated Process

The swelling behavior of sPEEK membranes: a thermally activated process associated to the β-relaxation crossover.

Inverse Ostwald Ripening and Self-Organization of Nanoclusters due to Ion Irradiation

2000 ◽  
Vol 647 ◽  
Author(s):  
K.-H. Heinig ◽  
B. Schmidt ◽  
M. Strobel ◽  
H. Bernas
Keyword(s):  
Phase Separation ◽  
Ion Implantation ◽  
Ostwald Ripening ◽  
Ion Irradiation ◽  
Experimental Studies ◽  
Self Organization ◽  
Mathematical Treatment ◽  
Thermodynamical Equilibrium ◽  
Unusual Behavior ◽  
Thermally Activated

AbstractUnder ion irradiation collisional mixing competes with phase separation if the irradiated solid consists of immiscible components. If a component is a chemical compound, there is another competition between the collisional forced chemical dissociation of the compound and its thermally activated re-formation. Especially at interfaces between immiscible components, irradiation processes far from thermodynamical equilibrium may lead to new phenomena. If the formation of nanoclusters (NCs) occurs during ion implantation, the phase separation caused by ion implantation induced supersaturation can be superimposed by phenomena caused by collisional mixing. In this contribution it will be studied how collisional mixing during high-fluence ion implantation affects NC synthesis and how ion irradiation through a layer of NCs modifies their size and size distribution. Inverse Ostwald ripening of NCs will be predicted theoretically and by kinetic lattice Monte-Carlo simulations. The mathematical treatment of the competition between irradiation-induced detachment of atoms from clusters and their thermally activated diffusion leads to a Gibbs-Thomson relation with modified parameters. The predictions have been confirmed by experimental studies of the evolution of Au NCs in SiO2 irradiated by MeV ions. The unusual behavior results from an effective negative capillary length, which will be shown to be the reason for inverse Ostwald ripening. Another new phenomenon to be addressed is self-organization of NCs in a d-layer parallel to the Si/SiO2 interface. Such d-layers were found when the damage level at the interface was of the order of 1-3 dpa. It will be discussed that the origin of the d-layer of NCs can be assigned to two different mechanisms: (i) The negative interface energy due to collisional mixing gives rise to the formation of tiny clusters of substrate material in front of the interface, which promotes heteronucleation of the implanted impurities. (ii) Collisional mixing in the SiO2produces diffusing oxygen, which may be consumed by the Si/SiO2 interface. A thin layer parallel to the interface becomes denuded of diffusing oxygen, which results in a strong pile up of Si excess. This Si excess promotes heteronucleation too. Independent of the dominating mechanism of self-organization of a d-layer of NCs, its location in SiO2 close to the SiO2/Si interface makes it interesting for non-volatile memory application.

RBS/Channeling Diffusion Studies of High Energy Au Implanted Mg Single Crystals

1991 ◽  
Vol 235 ◽  
Author(s):  
R. C. Da Selva ◽  
M. F. Da Silva ◽  
L. Thomé ◽  
A. A. Melo ◽  
J. C. Soares
Keyword(s):  
Single Crystals ◽  
Temperature Regime ◽  
High Energy ◽  
Back Diffusion ◽  
Thermally Activated ◽  
Diffusion Studies ◽  
Higher Temperature ◽  
Diffusion Behaviour ◽  
Thermally Activated Process

ABSTRACTRBS/channeling analyses of high energy Au implantation into Mg are presented. The diffusion behaviour of Au was studied and the occurrence of essentially two distinct regimes were observed: the segregation regime at lower temperatures correlated with the damage introduced by the high energy implantation and the higher temperature regime as a normal thermally activated process of back-diffusion.

Thermally activated process in deformed alpha titanium

1988 ◽  
Vol 38 (5) ◽  
pp. 491-493 ◽  
Author(s):  
P. Lukáč ◽  
Z. Trojanová ◽  
F. Chmelík ◽  
M. Hamerský ◽  
V. A. Moskalenko
Keyword(s):  
Thermally Activated ◽  
Alpha Titanium ◽  
Thermally Activated Process

NMR Relaxation Studies of Ferroelectric Colemanite

1973 ◽  
Vol 51 (9) ◽  
pp. 1005-1011 ◽  
Author(s):  
A. Watton ◽  
H. E. Petch ◽  
M. M. Pintar
Keyword(s):  
Phase Transition ◽  
Larmor Frequency ◽  
Lattice Relaxation ◽  
Proton Spin ◽  
Mode Frequency ◽  
Spin Lattice Relaxation ◽  
Water Molecules ◽  
Thermally Activated ◽  
Molecular Group ◽  
Thermally Activated Process

Proton spin–lattice relaxation of the Zeeman reservoir in the laboratory and rotating frames and of the dipolar reservoir have been studied in ferroelectric colemanite. These studies indicate the presence of two relaxation mechanisms which can be related to motions of the water molecules. The first, referred to as the flip mode and identified with 180° flips of the water molecules about their H—O—H bisectrices, is characterized by a correlation time and U-shaped relaxation minimum expected for a normal thermally activated process. The second, referred to as the jump mode and associated with a structural configuration change, produces a cusp-shaped dip in the relaxation over a very small temperature range in the vicinity of the phase transition. Above the transition temperature, the jump mode frequency is higher than the Larmor frequency and the relaxation behavior is that expected for two thermally activated processes in the white spectral region. However, in the vicinity of the phase transition, the water molecules are tightly coupled to the structure as a whole and the jump mode frequency is determined by the structural stability of the crystal. In this region its behavior is no longer that of a thermally activated process for an isolated molecular group and its frequency approaches zero critically near the phase transition.

scholarly journals DC Electrical Ageing of XLPE under Hydrostatic Pressure

2017 ◽  
Vol 2017 ◽  
pp. 1-5 ◽  
Author(s):  
Fadila Benlizidia Lalam ◽  
Faouzi Djemmal
Keyword(s):  
Hydrostatic Pressure ◽  
Direct Current ◽  
Atmospheric Pressure ◽  
Pressure Effect ◽  
Power Model ◽  
Lifetime Data ◽  
Confidence Bounds ◽  
Polyethylene Films ◽  
Thermally Activated ◽  
Thermally Activated Process

The experimental electrical ageing, of cross-linked polyethylene films 100 μm thick, was investigated under high hydrostatic pressure of 300 bar and at atmospheric pressure. The tests are conducted on direct current (dc) for up to 1000 h ageing and at temperature of 70°C. The use of the Weibull statistic, with the estimation of confidence bounds at 90%, has shown that the hydrostatic pressure has a real effect on the lifetime. These lifetime data are qualitatively analyzed with the inverse power model. It was found that thermally activated process is able to describe the pressure effect on the electrical ageing of XLPE.

Sign in / Sign up

Export Citation Format

Share Document