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Sunday 1st of July
2001 (Brasserie de
l'Univers) |
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Due to the limited number of
participants,
please register prior to May
15 |
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|
| 09.00 |
Energy and forces
in dielectrics
Charged dielectrics have the
specificity to be subjected to long range interactions within the material
itself. This modifies the usual energy terms of the thermodynamic
potentials and adds particular new coupling in case of polarization
equilibrium. The grounds of these approaches will be recalled.
Consequences on the dissipate behaviour (adhesion, wearing) and the
catastrophic ones (fracture, electrical breakdown, flashover) will be
developped.
Gilles Damamme - CEA Le Ripault, Mons
(F) |
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... b r e a k
... |
| 11.00 |
The story of an
electric charge confined in an insulating material
Electronic band structure of a perfect insulator. Polaron
concept and charge transport on free states. Structural and chemical
disorder in insulators : Anderson localized states. Weak localisation and
charge transport on band tails Anderson states. Strong localisation on
impurity states and charge trapping.
Guy Blaise - Univ.
Paris-Sud, Lab. de Physique des Solides, Orsay (F) |
|
|
| 14.00 |
Characterization
methods of insulators
Dielectric have both
mechanical and electrical elementary properties and also coupled ones
(electro- striction). Their characterization must also take into account
the way charges are trapped and detrapped as their conduction properties.
Technical limitations of their use depend on these phenomena and can be
better characterized when referring to their elementary properties. What
must be measured and how to do it will be deduced from the previous
analysis.
Gilles Damamme - CEA Le Ripault, Mons
(F) |
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... b r e a k
... |
| 16.00 |
Technological
applications of insulating materials : the accurracy of theories and
methods
Technological applications of
insulating materials are numerous and concern as well electric as
mechanical engineering. In all case, catastrophic damages (breakdown,
fracture, ageing, ...) are not easy explained by conventional theories. In
fact these theories consider incomplete balance of energy. Particularly,
the polarisation energy generally is neglected. In this way
characterisation methods of insulating materials have to take into account
not only the stable space charge but essentially the dynamic formation and
diffusion of the charges during the time life of the material or
systems.
Daniel Tréheux - IFOS, Ecole Centrale de
Lyon, Ecully (F) |
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|
| 19.00 |
Free discussion
with buffet
Space charge in the surface region and near
interfaces
This free discussion will emphazise
the innovative ideas related to space charge, with a special attention to
phenomena occuring near surfaces and interfaces. The energy localization
resulting from charge trapping, and the subsequent effects on ageing and
breakdown phenomena will be discussed. The suitable procedures and the
pertinent parameters to be measured in order to solve technological
problems will be considered. |
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Participants are
encouraged to prepare questions or/and comments on debatable points
which could be submitted to the discussion during this convivial
session. |
