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See detailLaser cladding as repair technology for Ti6Al4V alloy: Influence of building strategy on microstructure and hardness
Paydas, Hakan ULg; Mertens, Anne ULg; Carrus, Raoul et al

in Materials & Design (in press)

Laser cladding is a metal deposition technique used to fabricate or repair components made from high value metallic alloys. In the present work Ti-6Al-4V deposits with variable thickness are made to ... [more ▼]

Laser cladding is a metal deposition technique used to fabricate or repair components made from high value metallic alloys. In the present work Ti-6Al-4V deposits with variable thickness are made to assess the use of laser cladding as a repair technology. Both the effect of the building strategy (BS) and the incident energy (IE) on the metallurgical characteristics of the deposits in relation to their complex thermal history have been studying. It is shown that for the configuration consisting in a decreasing track length (DTL) under high IE, a gradient of cooling rate exists that leads to the presence of different phases within the microstructure. Conversely homogeneous microstructures are present either for the configuration with a constant track length (CTL) under high IE, and for the strategy obtained from a DTL under low IE. Depending on the possible heat accumulation the nature of the phases are determined together with hardness maps within the deposits. Some qualification criteria are set prior to tensile tests to selected the adequate candidate-deposit that does not weaken the cladded material when it is stressed. A thermo-metallurgical scheme is proposed that helps understanding the effect of both the BS and the IE on the microstructure. [less ▲]

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See detailLaser control in a bifurcating region
Sugny, Dominique; Kontz, Cyrill; Ndong, Mamadou et al

in Physical Review. A (2006), 74(4), 0434191-14

We present a complete analysis of the laser control of a model molecular system using both optimal control theory and adiabatic techniques. This molecule has a particular potential energy surface with a ... [more ▼]

We present a complete analysis of the laser control of a model molecular system using both optimal control theory and adiabatic techniques. This molecule has a particular potential energy surface with a bifurcating region connecting three potential wells which allows a variety of processes such as isomerization, tunneling, or implementation of quantum gates on one or two qubits. The parameters of the model have been chosen so as to reproduce the main features of H3CO which is a molecule benchmark for such dynamics. We show the feasibility of different processes and we investigate their robustness against variations of laser field. We discuss the conditions under which each method of control gives the best results. We also point out the relation between optimal control theory and local control. [less ▲]

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See detailLaser control in open molecular systems: STIRAP and optimal control
Sugny, Dominique; Ndong, Mamadou; Lauvergnat, David et al

in Journal of Photochemistry and Photobiology A : Chemistry (2007), 190

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See detailLaser control in open quantum systems: preliminary analysis toward the Cope rearrangement control in methyl-cyclopentadienylcarboxylate dimer
Dive, Georges ULg; Robiette, Raphaël; Chenel, Aurélie et al

in Theoretical Chemistry Accounts : Theory, Computation, & Modeling (2012), 131(6), 1236-1247

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See detailLaser Cooling of Iron Atoms
Huet, Nicolas ULg; Krins, Stéphanie ULg; Bastin, Thierry ULg

Poster (2013, March 21)

We report on the first laser cooling of Iron atoms. Our laser cooling setup makes use of 2 UV laser radiations sent colinearly in a 0.8 m Zeeman slower. One laser is meant for optical pumping of the Iron ... [more ▼]

We report on the first laser cooling of Iron atoms. Our laser cooling setup makes use of 2 UV laser radiations sent colinearly in a 0.8 m Zeeman slower. One laser is meant for optical pumping of the Iron atoms from the ground state to the lowest energy metastable state. The second laser cools down the atoms using a quasi-perfect closed transition from the optically pumped metastable state. The velocity distribution at the exit of the Zeeman slower is obtained from a probe laser crossing the atomic beam at an angle of 50 degrees. The fluorescence light is detected using a photomultiplier tube coupled with a boxcar analyzer. The Iron atom beam is produced with a commercial effusion cell working at around 1600°C. Our laser radiations are stabilized using standard saturated-absorption signals in both an Iron hollow cathode absorption cell and an Iodine cell. [less ▲]

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See detailLaser cooling of Iron atoms
Huet, Nicolas ULg; Krins, Stéphanie ULg; Bastin, Thierry ULg

Poster (2012, July 24)

We report on the first laser cooling of Iron atoms. Our laser cooling setup makes use of 2 UV laser radiation sent colinearly in a 0.8 m Zeeman slower. One laser is meant for optical pumping of the Iron ... [more ▼]

We report on the first laser cooling of Iron atoms. Our laser cooling setup makes use of 2 UV laser radiation sent colinearly in a 0.8 m Zeeman slower. One laser is meant for optical pumping of the Iron atoms from the ground state to the lowest energy metastable state. The second laser cools down the atoms using a quasi-perfect closed transition from the optical pumped metastable state. The velocity distribution at the exit of the Zeeman slower is obtained from a probe laser crossing the atom beam at an angle of 50 degrees. The fluorescence light is detected using a photomultiplier tube coupled with a boxcar analyzer. The Iron atom beam is produced with a commercial effusion cell working at around 1950 K. Our laser radiations are stabilized using standard saturated-absorption signals in both an Iron hollow cathode absorption cell and an Iodine cell. We will present our experimental setup, as well as the first evidences of cooled down Iron atoms at the exit of the Zeeman slower. [less ▲]

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See detailLaser Cooling of Iron Atoms
Bastin, Thierry ULg; Huet, Nicolas ULg; Krins, Stéphanie ULg

Conference (2013, March 18)

We report on the first laser cooling of Iron atoms. Our laser cooling setup makes use of 2 UV laser radiation sent colinearly in a 0.8~m Zeeman slower. One laser is meant for optical pumping of the Iron ... [more ▼]

We report on the first laser cooling of Iron atoms. Our laser cooling setup makes use of 2 UV laser radiation sent colinearly in a 0.8~m Zeeman slower. One laser is meant for optical pumping of the Iron atoms from the ground state to the lowest energy metastable state. The second laser cools down the atoms using a quasi-perfect closed transition from the optical pumped metastable state. The velocity distribution at the exit of the Zeeman slower is obtained from a probe laser crossing the atom beam at an angle of 50 degrees. The fluorescence light is detected using a photomultiplier tube coupled with a boxcar analyzer. The Iron atom beam is produced with a commercial effusion cell working at around 1950 K. Our laser radiations are stabilized using standard saturated-absorption signals in both an Iron hollow cathode absorption cell and an Iodine cell. We will present our experimental setup, as well as the first evidences of cooled down Iron atoms at the exit of the Zeeman slower. [less ▲]

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See detailLaser cooling of new atomic species - scheme of operation
Saint-Georges, P.; Krins, Stéphanie ULg; Bastin, Thierry ULg

Poster (2008)

Detailed reference viewed: 7 (1 ULg)
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See detailLaser steered ultrafast quantum dynamics of electrons in LiH.
Remacle, Françoise ULg; Nest, M.; Levine, R. D.

in Physical Review Letters (2007), 99(18), 183902

The response of the electronic system of LiH to a few-cycle strong field is computed by a time-dependent multiconfiguration method using a large, adaptive, basis set. The intensity, pulse duration ... [more ▼]

The response of the electronic system of LiH to a few-cycle strong field is computed by a time-dependent multiconfiguration method using a large, adaptive, basis set. The intensity, pulse duration, polarization, and phase of carrier frequency can all be tuned to steer the motion of the electrons. It is shown possible to, e.g., direct the electrons to move along the Li-H bond or normal to it. By shifting the phase, the electrons can be driven toward the Li nucleus or away from it. When the pulse is polarized not along the bond the result is a rotation of the charge density. [less ▲]

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See detailLaser thermoreflectance for semiconductor thin films metrology
Gailly, Patrick ULg; Hastanin, Juriy ULg; Duterte, Charles et al

in Wehrspohn, R. B., Gombert, A (Ed.) Photonics for Solar Energy Systems IV (2012, June)

We present a thermoreflectance-based metrology concept applied to compound semiconductor thin films off-line characterization in the solar cells scribing process. The presented thermoreflectance setup has ... [more ▼]

We present a thermoreflectance-based metrology concept applied to compound semiconductor thin films off-line characterization in the solar cells scribing process. The presented thermoreflectance setup has been used to evaluate the thermal diffusivity of thin CdTe films and to measure eventual changes in the thermal properties of 5 μm CdTe films ablated by nano and picosecond laser pulses. The temperature response of the CdTe thin film to the nanosecond heating pulse has been numerically investigated using the finite-difference time-domain (FDTD) method. The computational and experimental results have been compared. [less ▲]

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See detailLaser-assisted dielectronic recombination in C4+ ions
Bachau, H.; Gayet, R.; Lambropoulos, P. et al

in Journal of Physics : B Atomic Molecular & Optical Physics (1998), 31(14), 3263-3280

We study the effect of laser-driven transitions between autoionizing resonances on the dielectronic recombination rates observed after the formation of such resonances in electron-ion collisions. The ... [more ▼]

We study the effect of laser-driven transitions between autoionizing resonances on the dielectronic recombination rates observed after the formation of such resonances in electron-ion collisions. The autoionizing states of S-1(e) and P-1(0) symmetry belonging to the 2l2l' and 2l3l' configurations of C4+ are considered. The resonance parameters are calculated in the Feshbach formalism and compared with other accurate calculations, and transition dipole moments between the autoionizing states are obtained. The rates of dielectronic recombination and autoionization under the influence of the laser field are calculated using the density matrix approach for realistic parameters. A simple formulation of the problem is also proposed in the resolvent operator technique. The feasibility of an experiment is discussed. [less ▲]

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See detailLaser-induced breakdown spectroscopy for analysis of soil elements
Lin, Zhaoxiang; Li, Jie ULg; Liu, Linmei et al

in High Power Laser and Particle Beams (2009), 21(6), 817820

A laser—induced breakdown spectroscopy(LIBS)set—up has been established,and a series of experiments have been carried out with soil samples.The calibration curves of the lines intensities versus the mass ... [more ▼]

A laser—induced breakdown spectroscopy(LIBS)set—up has been established,and a series of experiments have been carried out with soil samples.The calibration curves of the lines intensities versus the mass fraction of the elements were acquired by the experiment.Eighteen elements including Mg,Ca and Na were found in the sample of the soil around the South—Central University for Nationalities by qualitative analysis.Only three elements,Fe,Mg and Ca,were found in the rock at Zhuyufeng peak.These results indicate that the physical composition of soil sample impact on the precision of LIBS. [less ▲]

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See detailLaser-induced choroidal neovascularization model to study age-related macular degeneration in mice.
LAMBERT, Vincent ULg; Lecomte, Julie ULg; Hansen, Sylvain ULg et al

in Nature Protocols (2013), 8(11), 2197-2211

The mouse model of laser-induced choroidal neovascularization (CNV) has been used extensively in studies of the exudative form of age-related macular degeneration (AMD). This experimental in vivo model ... [more ▼]

The mouse model of laser-induced choroidal neovascularization (CNV) has been used extensively in studies of the exudative form of age-related macular degeneration (AMD). This experimental in vivo model relies on laser injury to perforate Bruch's membrane, resulting in subretinal blood vessel recruitment from the choroid. By recapitulating the main features of the exudative form of human AMD, this assay has served as the backbone for testing antiangiogenic therapies. This standardized protocol can be applied to transgenic mice and can include treatments with drugs, recombinant proteins, antibodies, adenoviruses and pre-microRNAs to aid in the search for new molecular regulators and the identification of novel targets for innovative treatments. This robust assay requires 7-14 d to complete, depending on the treatment applied and whether immunostaining is performed. This protocol includes details of how to induce CNV, including laser induction, lesion excision, processing and different approaches to quantify neoformed vasculature. [less ▲]

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See detailLaser-induced contamination and its impact on laser damage threshold
Schröder, H; Wagner, P; Kokkinos, Dimitrios ULg et al

in Laser-induced contamination and its impact on laser damage threshold (2013, November 14)

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See detailLaser-induced transitions between triply excited hollow states
Madsen, L. B.; Schlagheck, Peter ULg; Lambropoulos, P.

in Physical Review. A (2000), 62(6), 062719

Using complex scaling and a correlated basis constructed in terms of B splines, we calculate the Li+ photoion yield in the presence of a laser-induced coupling between the triply excited 2s(2)2p(P-2(0 ... [more ▼]

Using complex scaling and a correlated basis constructed in terms of B splines, we calculate the Li+ photoion yield in the presence of a laser-induced coupling between the triply excited 2s(2)2p(P-2(0)) and 2s2p(2)(D-2(e)) resonances in lithium, the first of which is assumed to be excited by synchrotron radiation from the ground state. The laser coupling between the triply excited states is shown to lead to a significant and readily measurable modification of the line profile which provides a unique probe of the dipole strength between highly correlated triply excited states. We also present results for some higher-lying triply excited states of P-2(0) symmetry. [less ▲]

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See detailLaser-induced transitions between triply excited hollow states
Madsen, L. B.; Schlagheck, Peter ULg; Lambropoulos, P.

in Physical Review Letters (2000), 85(1), 42-45

We present an ab initio calculation of the Li+ photoion yield in the presence of laser coupling between the triply; excited 2s(2)2p(2)P(o) and 2s2p(2) D-2(e) resonances in lithium, the first of which is ... [more ▼]

We present an ab initio calculation of the Li+ photoion yield in the presence of laser coupling between the triply; excited 2s(2)2p(2)P(o) and 2s2p(2) D-2(e) resonances in lithium, the first of which is assumed excited by synchrotron radiation from the ground state. The laser coupling between the triply excited states is shown to lead to a significant and readily measurable modification of the line profile which provides a unique probe of the dipole strength between highly correlated triply excited states. [less ▲]

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See detailLaser-induced-fluorescence lifetime measurements and relativistic Hartree-Fock oscillator strength calculations in singly ionized platinum
Quinet, Pascal ULg; Palmeri, P.; Fivet, V. et al

in Physical Review. A (2008), 77

Radiative lifetimes of eight odd-parity states of Pt II, in the energy range from 51 408 to 64 388 cm−1, have been measured by means of the time-resolved laser-induced-fluorescence technique. Free, singly ... [more ▼]

Radiative lifetimes of eight odd-parity states of Pt II, in the energy range from 51 408 to 64 388 cm−1, have been measured by means of the time-resolved laser-induced-fluorescence technique. Free, singly ionized platinum ions were obtained in a laser-produced plasma and a tunable laser with 1.5 ns duration pulse was used to selectively excite the Pt+ ions. The comparison of the experimental results with relativistic Hartree-Fock calculations emphasizes the importance of valence-valence correlation and of core-polarization effects in this complex ion. A new and extensive set of calculated oscillator strengths and transition probabilities is reported in the present paper. [less ▲]

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See detailLaser-probing measurements and calculations of lifetimes of the 5d D-2(3/2) and 5d D-2(5/2) metastable levels in BaII
Gurell, J.; Biémont, Emile ULg; Blagoev, K. et al

in Physical Review A (2007), 75(5), 1-6

The two metastable levels 5d(2)D(3/2) and 5d(2) D-5/2 in Ba II both show extremely long lifetimes of the order of several tens of seconds each. This has been found both by experiments and by theoretical ... [more ▼]

The two metastable levels 5d(2)D(3/2) and 5d(2) D-5/2 in Ba II both show extremely long lifetimes of the order of several tens of seconds each. This has been found both by experiments and by theoretical predictions. The small transition probabilities associated with these two levels make them interesting and challenging for theoreticians as well as for experimentalists. Several calculations and measurements of these two lifetimes have been made previously but discrepancies between the results are present. This article presents values of ??? = 89.4 +/- 15.6 s for the D-2(3/2) level and ??? = 32.0 +/- 4.6 s for the D-2(5/2) level measured in a beam-laser experiment performed at the ion storage ring CRYRING. These values are supported by our new calculations resulting in ???= 82.0 s for the D-2(3/2) level and ???= 31.6 s for the D-2(5/2) level. [less ▲]

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See detailLasers excimères: applications au micro-usinage
Gailly, Patrick ULg

Conference given outside the academic context (2006)

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See detailLasfe (CIL IV 2319 l) et quelques autres exemples d’usage abusif de l’épigraphie en phonétique historique
Purnelle, Gérald ULg

in Etudes Classiques (Namur, Belgium) (1993), 61

Detailed reference viewed: 17 (1 ULg)