Browsing
     by title


0-9 A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

or enter first few letters:   
OK
Full Text
Peer Reviewed
See detailFormation of Giant Luminous Arcs and Arclets Using an Optical Gravitational Lens Experiment
Surdej, Jean ULg; Refsdal, S.; Pospieszalska-Surdej, Anna ULg

in Kochanek, C. S.; Hewitt, Jacqueline N (Eds.) Astrophysical applications of gravitational lensing, Proceedings of the 173rd Symposium of the International Astronomical Union (1996)

Not Available

Detailed reference viewed: 46 (13 ULg)
Full Text
Peer Reviewed
See detailFormation of long-wavelength chlorophyllide (Chlide695) is required for the assembly of Photosystem II in etiolated barley leaves
Franck, Fabrice ULg; Eullaffroy, P.; Popovic, R.

in Photosynthesis Research (1997), 51(2), 107-118

Chlorophyll(ide) spectroscopic properties and Photosystem II assembly, monitored by 77 K variable fluorescence, were studied in etiolated barley leaves as a function of the extent of protochlorophyllide ... [more ▼]

Chlorophyll(ide) spectroscopic properties and Photosystem II assembly, monitored by 77 K variable fluorescence, were studied in etiolated barley leaves as a function of the extent of protochlorophyllide photoreduction by a single millisecond light flash of different intensities. Variable fluorescence, measured 2 hours after the flash, was only detected when the extent of phototransformation was higher than a threshold value of 0.4. Its development paralleled the formation of a chlorophyll emission component at 685 nm, which itself derived from long-wavelength chlorophyllide with an emission maximum at 695 nm. At low flash intensities, short-wavelength chlorophyllide forms preferentially accumulated and no Photosystem II fluorescence was detected after 2 hours. Chlorophyllide esterification was independent of the extent of phototransformation. These results suggested that the formation of long-wavelength chlorophyllide was essential for further assembly of Photosystem II. This interpretation was strengthened by the observed inhibition of both long-wavelength chlorophyllide formation and of variable fluorescence development in leaves treated with 6-aminolevulinic acid or in untreated leaves subjected to repeated flashes of low intensity. [less ▲]

Detailed reference viewed: 9 (0 ULg)
Full Text
Peer Reviewed
See detailFormation of micropores in a DS Ni-Ti-C alloy
Ji, Daoxin; Lecomte-Beckers, Jacqueline ULg; Habraken, Louis

in Proceedings Conference on High Temperature Alloys Gas Turbines (1982)

The aim of this experiment was to examine the formation of micropores during directional solidification of a Ni--5Ti--0.2C alloy in order to determine their precise origin and to verify some nearly ... [more ▼]

The aim of this experiment was to examine the formation of micropores during directional solidification of a Ni--5Ti--0.2C alloy in order to determine their precise origin and to verify some nearly developed theoretical formulae. A further aim is to elicit the factors responsible for the occurrence of the defects which seriously impair the mechanical properties of certain alloys. The technique of quenched directionally solidified rods was used in order to follow the development of solidification. The results show that solidification conditions influence microporosities formation through the fraction of eutectic and this suggests that it is possible to relate susceptibility to microporosity formation to the fraction of eutectic. The results also confirm that for solid solution alloys such as Ni--5Ti--0.2C, the fraction of eutectic increases when the ratio G/R (G: temp. gradient in mushy zone; R: solidification rate) decreases as described in the mathematical model developed. [less ▲]

Detailed reference viewed: 37 (2 ULg)
Peer Reviewed
See detailFormation of N2,3-ethanoguanine in DNA after in vitro treatment with the therapeutic agent, N-(2-chloroethyl)-N'-cyclohexyl-N-nitrosourea
Habraken, Yvette ULg; Carter, C.; Kirk, M. et al

in Carcinogenesis (1990), 11(2), 223-228

Detailed reference viewed: 4 (0 ULg)
Peer Reviewed
See detailThe Formation of National Elites de A. Kappeler (ed.)
Martiniello, Marco ULg

in Ethnic and Racial Studies (1995), 18(2), 421-422

Detailed reference viewed: 18 (0 ULg)
Peer Reviewed
See detailFormation of nick instabilities due to particle clustering along crystal interfaces
Vandewalle, Nicolas ULg; Ausloos, Marcel ULg; Cloots, Rudi ULg

in Physical Review. E : Statistical Physics, Plasmas, Fluids, and Related Interdisciplinary Topics (1997), 56(4), 4042-4047

The kinetic growth of crystal grains is simulated on a square lattice in the presence of mobile particles. The model is based on the Eden and the dynamic epidemic models. Trapping of the particles by the ... [more ▼]

The kinetic growth of crystal grains is simulated on a square lattice in the presence of mobile particles. The model is based on the Eden and the dynamic epidemic models. Trapping of the particles by the advancing front and a short-range repulsion of the particles by the front are both allowed. The grain boundary morphology is studied through the kink density concept and the spatial distribution of particles is discussed. Indeed, the clustering of particles along the crystal edges is found to induce the formation of so-called nick instabilities at the liquid-solid interface. The particles, when trapped near such instabilities, occur as oblique filamentary structures in the crystal matrix, just like river networks. These findings agree with recent experimental observations. The numerical laws are also explained by theoretical arguments based on different characteristic lengths. [less ▲]

Detailed reference viewed: 8 (0 ULg)
Full Text
Peer Reviewed
See detailFormation of P Cygni line profiles in relativistically expanding atmospheres
Hutsemekers, Damien ULg; Surdej, Jean ULg

in Astrophysical Journal (1990), 361

The probabilistic approach of Surdej (1979) is followed to generalize the Sobolev (1958) formalism to the case of special relativity, in order to interpret accurately the P Cygni line profiles observed in ... [more ▼]

The probabilistic approach of Surdej (1979) is followed to generalize the Sobolev (1958) formalism to the case of special relativity, in order to interpret accurately the P Cygni line profiles observed in the spectrum of broad absorption-line quasars and supernovae. The expressions of the source function and of the line profile are derived, and it is shown that the relativistic P Cygni line profiles are significantly different from those computed in the framework of the classical theory. Thus, for increasing values of the terminal wind velocity, the red emission wing becomes definitely narrower than the blue one, while the line center emission increases. This is no longer symmetrical in accordance with the relativistic expression of the Doppler effect. [less ▲]

Detailed reference viewed: 16 (4 ULg)
Full Text
Peer Reviewed
See detailFormation of P Cygni Line Profiles in Relativistically Expanding Atmospheres. II. The Effect of the Continuum Frequency Shape and Limb Darkening of the Core
Hutsemekers, Damien ULg

in Astrophysical Journal (1993), 417

Abstract image available at: http://adsabs.harvard.edu/abs/1993ApJ...417...97H

Detailed reference viewed: 7 (2 ULg)
Full Text
Peer Reviewed
See detailFormation of P Cygni profiles with limb darkening of the stellar core
Surdej, Jean ULg

in Astrophysics & Space Science (1981), 79

In the framework of the Sobolev approximation, the effects of limb darkening of the stellar core on the formation of line profiles in rapidly expanding envelopes are investigated. For the case of outward ... [more ▼]

In the framework of the Sobolev approximation, the effects of limb darkening of the stellar core on the formation of line profiles in rapidly expanding envelopes are investigated. For the case of outward-accelerating envelopes, it is shown that the P Cygni profiles, calculated with and without limb darkening, do appear almost identical as long as the size of the envelope remains large with respect to the radius of the star. As the extent of the envelope decreases, the resulting profiles are found to differ appreciably close to the line center. When considering outward-decelerating (or equivalently inward-accelerating) envelopes, calculations with the limb darkening effects reveal that the P Cygni profiles are more strongly affected than in the previous case. These effects are specially important in the blue wing and near the center of the resulting line profiles, irrespective of the size of the envelope. [less ▲]

Detailed reference viewed: 48 (0 ULg)
Full Text
Peer Reviewed
See detailFormation Of Plant Cuticle: Evidence For The Occurrence Of The Peroxygenase Pathway
Lequeu, J.; Fauconnier, Marie-Laure ULg; Chammai, A. et al

in Plant Journal (The) (2003), 36(2),

Detailed reference viewed: 10 (3 ULg)
Full Text
Peer Reviewed
See detailFormation of polyamide 12-polyisoprene core-shell particles in polystyrene by reactive blending
Koulic, Christian; François, G.; Jérôme, Robert ULg

in Macromolecules (2004), 37(14), 5317-5322

Polyamide 12 (PA12)-polyisoprene (PIP) particles with a thermoplastic core and a rubbery shell have been prepared in a thermoplastic matrix (PS) by reactive blending. For this purpose, an anhydride-end ... [more ▼]

Polyamide 12 (PA12)-polyisoprene (PIP) particles with a thermoplastic core and a rubbery shell have been prepared in a thermoplastic matrix (PS) by reactive blending. For this purpose, an anhydride-end-capped PS-b-PIP diblock (PS-b-PIP-anh) has been reacted with PA12 chains end-capped (50% of them) by a primary amine and dispersed in PS. A PS-b-PIP-PA12 triblock has been formed at the interface between the PS matrix and the dispersed PA12 microdomains. Thus, the phase morphology consists of PA12 core-PIP shell particles dispersed in PS. The nonreacted PA12 with respect to PS-b-PIP-anh dictates the size of the polyamide (core) domains, and the reactive diblock (mainly the molecular weight of the PIP block) imposes the shell thickness and modulates the core size by its capacity to compatibilize PA12 and the thermoplastic matrix. [less ▲]

Detailed reference viewed: 39 (3 ULg)
Full Text
Peer Reviewed
See detailFormation of resonance doublet profiles in rapidly expanding envelopes
Surdej, Jean ULg

in Astrophysics & Space Science (1980), 73

Sobolev's escape probability method is used to investigate the transfer of spectral line radiation for a resonance doublet in a rapidly expanding envelope. A three-level atom model is used to derive ... [more ▼]

Sobolev's escape probability method is used to investigate the transfer of spectral line radiation for a resonance doublet in a rapidly expanding envelope. A three-level atom model is used to derive expressions for the spectral radiation fields J12 and J13, the resulting radiative force exerted per atom, and the resonance doublet profile for the cases of outward-accelerating (or equivalently inward-decelerating) and outward-decelerating (or equivalently inward-accelerating) envelopes. Criteria are deduced under which resonance doublet profiles formed in outward-accelerating and/or outward-decelerating envelopes would appear to be resolved into double P Cygni profiles. [less ▲]

Detailed reference viewed: 7 (0 ULg)
Full Text
Peer Reviewed
See detailFormation of Stripelike Flux Patterns Obtained by Freezing Kinematic Vortices in a Superconducting Pb Film
Silhanek, Alejandro ULg; Milosevic, M. V.; Kramer, R. B. G. et al

in Physical Review Letters (2010), 104(1),

We demonstrate experimentally and theoretically that the dissipative state of superconducting samples with a periodic array of holes at high current densities consists of flux rivers resulting from a ... [more ▼]

We demonstrate experimentally and theoretically that the dissipative state of superconducting samples with a periodic array of holes at high current densities consists of flux rivers resulting from a short-range attractive interaction between vortices. This dynamically induced vortex-vortex attraction results from the migration of quasiparticles out of the vortex core (kinematic vortices). We have directly visualized the formation of vortex chains by scanning Hall probe microscopy after freezing the dynamic state by a field cooling procedure at a constant bias current. Similar experiments carried out in a sample without holes show no hint of flux river formation. We shed light on this nonequilibrium phenomena modeled by time-dependent Ginzburg-Landau simulations. [less ▲]

Detailed reference viewed: 7 (0 ULg)
Full Text
Peer Reviewed
See detailFormation of the 67-kDa laminin receptor by acylation of the precursor.
Buto, S.; Tagliabue, E.; Ardini, E. et al

in Journal of Cellular Biochemistry (1998), 69(3), 244-51

Even though the involvement of the 67-kDa laminin receptor (67LR) in tumor invasiveness has been clearly demonstrated, its molecular structure remains an open problem, since only a full-length gene ... [more ▼]

Even though the involvement of the 67-kDa laminin receptor (67LR) in tumor invasiveness has been clearly demonstrated, its molecular structure remains an open problem, since only a full-length gene encoding a 37-kDa precursor protein (37LRP) has been isolated so far. A pool of recently obtained monoclonal antibodies directed against the recombinant 37LRP molecule was used to investigate the processing that leads to the formation of the 67-kDa molecule. In soluble extracts of A431 human carcinoma cells, these reagents recognize the precursor molecule as well as the mature 67LR and a 120-kDa molecule. The recovery of these proteins was found to be strikingly dependent upon the cell solubilization conditions: the 67LR is soluble in NP-40-lysis buffer whereas the 37LRP is NP-40-insoluble. Inhibition of 67LR formation by cerulenin indicates that acylation is involved in the processing of the receptor. It is likely a palmitoylation process, as indicated by sensitivity of NP-40-soluble extracts to hydroxylamine treatment. Immunoblotting assays performed with a polyclonal serum directed against galectin3 showed that both the 67- and the 120-kDa proteins carry galectin3 epitopes whereas the 37LRP does not. These data suggest that the 67LR is a heterodimer stabilized by strong intramolecular hydrophobic interactions, carried by fatty acids bound to the 37LRP and to a galectin3 cross-reacting molecule. [less ▲]

Detailed reference viewed: 16 (0 ULg)
Full Text
Peer Reviewed
See detailFormation of upper rim acylated calix[4]arenes using a sacrifici al zinc anode
Louati, Alain; Vataj, Rame; Gabelica, Valérie ULg et al

in Tetrahedron Letters (2005), 46(44), 7499-7502

A straightforward electrosynthetic method is described, which allows upper rim acylation of non-p-halogenated calix[4]-arenes. For example, a solution of tetrapropoxycalix[4]arene 4 was electrolysed in ... [more ▼]

A straightforward electrosynthetic method is described, which allows upper rim acylation of non-p-halogenated calix[4]-arenes. For example, a solution of tetrapropoxycalix[4]arene 4 was electrolysed in the presence of ZnBr2, in an undivided cell fitted with a sacrificial zinc anode using pure acetonitrile as solvent, yielding an organozinc species, which was then treated with acetyl chloride in the presence of a palladium catalyst to afford 5,11-diacety1-25,26,27,28-tetrapropoxycalix[4]arene 5 in ca. 35% yield after workup. (c) 2005 Elsevier Ltd. All rights reserved. [less ▲]

Detailed reference viewed: 81 (4 ULg)
Full Text
Peer Reviewed
See detailFormation on copper of perfluoroetheralkyl-thiol and dithiol self-assembled monolayers with a perfluoropolyether overlayer
Denayer, Jessica ULg; Volcke, C.; Delhalle, J. et al

in Electrochimica Acta (2012), 63

Copper based electrical contacts are widely used thanks to the high electric conductivity and low cost of this metal. However, the efficiency and durability of the devices can be affected by several ... [more ▼]

Copper based electrical contacts are widely used thanks to the high electric conductivity and low cost of this metal. However, the efficiency and durability of the devices can be affected by several factors including metal oxidation and corrosion. In this paper, a bilayer mixed lubricant has been developed to attenuate those hindrances. It is composed of an immobile layer (perfluoroetheralkyl-thiol and dithiol SAMs) to reduce copper corrosion, and by a mobile layer (PFPE lubricant) to reduce the friction. The perfluorinated SAMs have been successfully achieved on copper and the resulting monolayers exhibit high blocking and insulating behaviors. The spreading of PFPE lubricant on those self-assemblies has then been performed. The resulting bilayer systems are homogeneous and completely wetted by the lubricant. Furthermore, the bilayer systems show higher retention of the thin lubricant film than the bare copper. © 2011 Elsevier Ltd. All rights reserved. [less ▲]

Detailed reference viewed: 20 (2 ULg)
See detailLa formation professionnelle continue et ses usages. Le cas des secteurs industriels en Région wallonne
Guillaume, Jean-François ULg

in Guyot, Jean-Luc; Mainguet, Christine; Van Haeperen, Béatrice (Eds.) La formation professionnelle continue. L'individu au coeur des dispositifs (2003)

Au départ d'une enquête réalisée en 2001 auprès de 341 travailleurs actifs en 1997 ou 1998 dans un secteur industriel en Région wallonne, l'auteur analyse les pratiques en matière de formation continue en ... [more ▼]

Au départ d'une enquête réalisée en 2001 auprès de 341 travailleurs actifs en 1997 ou 1998 dans un secteur industriel en Région wallonne, l'auteur analyse les pratiques en matière de formation continue en les situant en tant que composantes des trajectoires professionnelles. Ces trajectoires sont identifiées au départ des moments de scansion que constituent les ruptures dans l'activité ou les changements d'employeur, et du contenu des activités qui sont exercées. Dans un contexte où la mobilité et la flexibilité s'imposent dans l'organisation du travail, la formation professionnelle continue semble revêtir des fonctions oscillant entre un préliminaire requis pour l'entrée en emploi et un mode d'intégration ou de gestion de la main-d'oeuvre au sein des entreprises. Même si les données disponibles ne permettent pas d'établir de stricts liens de causalité entre les événements présents dans le parcours professionnel, on notera que l'accès à la formation continue n'est pas l'indice, la garantie ou la conséquence d'une trajectoire en emploi plus ou moins stable - ou plus ou moins heurtée - et que les bénéfices escomptés à l'issue d'une formation continue ne sont pas équivalents. Tous n'en tirent pas un même profit : si pour les uns, faiblement dotés en capital scolaire, la formation a permis d'accéder au marché de l'emploi, pour d'autres, plus riches en capital scolaire, elle offre davantage d'opportunités de promotion, d'évolution salariale et de modifications des tâches quotidiennes qui sont réalisées. [less ▲]

Detailed reference viewed: 18 (2 ULg)