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See detailOptical methods for non-contact measurements of membranes
Roose, Stéphane ULg; Stockman, Yvan ULg; Rochus, Pierre ULg et al

in Acta Astronautica (2009), 65(9-10), 1317-1329

Structures for space applications very often suffer stringent mass constraints. Lightweight structures are developed for this purpose, through the use of deployable and/or inflatable beams, and thin-film ... [more ▼]

Structures for space applications very often suffer stringent mass constraints. Lightweight structures are developed for this purpose, through the use of deployable and/or inflatable beams, and thin-film membranes. Their inherent properties (low mass and small thickness) preclude the use of conventional measurement methods (accelerometers and displacement transducers for example) during on-ground testing. In this context, innovative non-contact measurement methods need to be investigated for these stretched membranes. The object of the present project is to review existing measurement systems capable of measuring characteristics of membrane space-structures such as: dot-projection videogrammetry (static measurements), stereo-correlation (dynamic and static measurements), fringe projection (wrinkles) and 3D laser scanning vibrometry (dynamic measurements). Therefore, minimum requirements were given for the study in order to have representative test articles covering a wide range of applications. We present test results obtained with the different methods on our test articles. [less ▲]

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See detailOPTICAL MULTICHANNEL ANALYSIS OF PROTOCHLOROPHYLLIDE PHOTOTRANSFORMATION IN DETERGENT-SOLUBILIZED ETIOPLAST MEMBRANES OF WHEAT
Franck, Fabrice ULg; OUAZZANI, M. A.; DUJARDIN, E. et al

in Zeitschrift Fur Naturforschung C-A Journal Of Biosciences (1994), 49(1-2), 125-131

Extracts of wheat etioplast membranes obtained after treatment with 7 mM n-octyl-beta-D-glucopyranoside (OG), n-dodecyl-beta-D-maltoside (DM) or Triton X-100 contained the three spectral forms of Pchlide ... [more ▼]

Extracts of wheat etioplast membranes obtained after treatment with 7 mM n-octyl-beta-D-glucopyranoside (OG), n-dodecyl-beta-D-maltoside (DM) or Triton X-100 contained the three spectral forms of Pchlide (the photoactive Pchlide(638) and Pchlide(638) and the inactive Pchlide(650)) in various relative amounds. The OG extract had a Pchlide composition close to that of the intact membranes whereas the DM extract was enriched in Pchlide(638) and the Triton extract was enriched in Pchlide(630). Measurements of the kinetics of phototransformation and of time-resolved absorbance spectra during phototransformation in continuous Light shows that the inactive Pchlide(630) is in fact slowly transformed to Chlide, especially in the Triton extract where this form is more abundant. Addition of NADPH favours the phototransformation of Pchlide(630) and the slow regeneration of Pchlide(638) and Pchlide(650) from Pchlide(630) in darkness after illumination. No such regeneration was however observed in the Triton extract. NADPH had only slight effects on the Chlide shift towards shorter wavelengths after phototransformation in solubilized membranes. [less ▲]

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See detailOptical non-linearity in disperse red 1 dye-doped sol-gel
Rosso, Vanessa ULg; Loicq, Jerôme ULg; Renotte, Yvon ULg et al

in Journal of Non-Crystalline Solids (2004), 342(1-3), 140-145

A third-order non-linear optical effect, the optical Kerr effect, was studied in DR1-doped sol-gel using the Z-scan method which allows studying both processes of non-linear absorption and refraction. The ... [more ▼]

A third-order non-linear optical effect, the optical Kerr effect, was studied in DR1-doped sol-gel using the Z-scan method which allows studying both processes of non-linear absorption and refraction. The materials under study are sol-gel substrates, amorphous silica glasses doped by the azo-dye Disperse Red 1. Modifying the conditions of the sol-gel synthesis, in particular the pH of the catalytic medium, enabled us to vary the morphology of the sol-gel substrate. Non-linear effects of various amplitudes were observed in so-gel substrates of various porosities, involving different non-linear mechanisms. (C) 2004 Elsevier B.V. All rights reserved. [less ▲]

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See detailOptical observations of comet Hale-Bopp (C/1995 O1) at large heliocentric distances before perihelion.
Rauer, H.; Arpigny, Claude ULg; Boehnhardt, H. et al

in Science (1997), 275

The activity of comet Hale-Bopp (C/1995 O1) was monitored monthly by optical imaging and long-slit spectroscopy of its dust and gas distribution over heliocentric distances of 4.6 to 2.9 AU. The observed ... [more ▼]

The activity of comet Hale-Bopp (C/1995 O1) was monitored monthly by optical imaging and long-slit spectroscopy of its dust and gas distribution over heliocentric distances of 4.6 to 2.9 AU. The observed band intensities of the NH[SUB]2[/SUB] radical and the H[SUB]2[/SUB]O[SUP]+[/SUP] ion cannot be explained by existing models of fluorescence excitation, warranting a reexamination of the corresponding production rates, at least at large heliocentric distances. Comparing the production rate of the CN radical to its proposed parent, HCN, shows no evidence for the need of a major additional source for CN in Hale-Bopp at large heliocentric distances. The dust and CN production rates are consistent with a significant amount of sublimation occurring from icy dust grains surrounding Hale-Bopp. [less ▲]

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See detailOptical Observations of Comet McNaught from La Silla
Snodgrass, C.; Fitzsimmons, A.; Jehin, Emmanuel ULg et al

in LPI contribution 1405 (2008)

Not Available

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See detailOptical observations of gravitational lenses
Surdej, Jean ULg; Claeskens, Jean-François ULg; Hutsemekers, Damien ULg et al

in Kayser, Rainer; Schramm, Thomas; Nieser, Lars (Eds.) Proceedings of the Hamburg conference on ’Gravitational Lenses’, Lecture Notes in Physics 406 (1992)

We report here on some of the major developments achieved on optical observations of gravitational lenses since the last conference devoted to 'Gravitational Lensing'.

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See detailOptical polarization of 203 QSOs (Sluse+, 2005)
Sluse, D.; Hutsemekers, Damien ULg; Lamy, H. et al

Textual, factual or bibliographical database (2004)

This Table contains linear polarization measurements (mainly in the V band) of 203 QSOs. First time measurements have been obtained for 184 objects. Among them 109 known radio emitters, 42 BAL and 1 ... [more ▼]

This Table contains linear polarization measurements (mainly in the V band) of 203 QSOs. First time measurements have been obtained for 184 objects. Among them 109 known radio emitters, 42 BAL and 1 gravitationally lensed QSO. (1 data file). [less ▲]

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See detailOptical Polarization of 47 QSOs (Lamy+, 2000)
Lamy, H.; Hutsemekers, Damien ULg

Textual, factual or bibliographical database (2000)

New broad-band linear polarization measurements are presented for a sample of 47 QSOs which includes 27 broad absorption line QSOs and 2 gravitational lens candidates. (2 data files).

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See detailOptical polarization of 47 quasi-stellar objects: The data
Lamy, H.; Hutsemekers, Damien ULg

in Astronomy and Astrophysics. Supplement Series (2000), 142

New broad-band linear polarization measurements are presented for a sample of 47 QSOs which includes 27 broad absorption line QSOs and 2 gravitational lens candidates. Tables 3 and 4 are also available in ... [more ▼]

New broad-band linear polarization measurements are presented for a sample of 47 QSOs which includes 27 broad absorption line QSOs and 2 gravitational lens candidates. Tables 3 and 4 are also available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/Abstract.html Based on observations collected at the European Southern Observatory (ESO, La Silla). [less ▲]

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See detailThe optical polarization of radio-loud and radio-intermediate broad absorption line quasi-stellar objects
Hutsemekers, Damien ULg; Lamy, H.

in Astronomy and Astrophysics (2000), 358

On the basis of a sample of approximately 50 broad absorption line quasi-stellar objects (BAL QSOs), we investigate possible correlations between BAL QSO radio properties and other spectral ... [more ▼]

On the basis of a sample of approximately 50 broad absorption line quasi-stellar objects (BAL QSOs), we investigate possible correlations between BAL QSO radio properties and other spectral characteristics, including polarization. For this purpose new polarization data have been obtained. The main result of our statistical study is the absence of significant correlations between the radio-to-optical flux ratio R[SUP]star [/SUP] and all other quantities: the polarization p_0 of the continuum, the slope of the continuum, the balnicity and detachment indices which characterize the BAL profiles, and the terminal velocity of the flow v_max. The claimed anticorrelation between R[SUP]star [/SUP] and v_max is therefore not confirmed, as well as the correlation between R[SUP]star [/SUP] and p_0 predicted by some models. Although marginally significant, the only possible correlations occur for the BAL QSOs with low-ionization troughs. Based on observations collected at the European Southern Observatory (ESO, La Silla) [less ▲]

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See detailOptical properties and structure of nanodiamonds
Raty, Jean-Yves ULg; Galli, G.

in Journal of Electroanalytical Chemistry (2005), 584(1 Sp. Iss. SI), 9-12

We present a theoretical study of the structure and optical properties of nanodiamonds. Using ab initio molecular dynamics simulation, we confirm that quantum confinement effects become negligible between ... [more ▼]

We present a theoretical study of the structure and optical properties of nanodiamonds. Using ab initio molecular dynamics simulation, we confirm that quantum confinement effects become negligible between 2 and 3 nm in size. In this size domain, specific surface reconstructions occur upon sample dehydrogenation, leading to fullerene-capped structures, or 'bucky diamonds' with absorption spectra similar to the experiment. We finally show that the HOMO and LUMO states are interface states in the reconstructed structures. (c) 2004 Elsevier B.V.. All rights reserved. [less ▲]

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See detailOptical properties of cosputterd Gold-Chromium alloy films
Slusark, W.; Lalevic, B.; Ausloos, Marcel ULg

in Journal of Applied Physics (1977), 48

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See detailOptical properties of thermochromic VO 2 thin films on stainless steel: Experimental and theoretical studies
Lafort, A.; Kebaili, H.; Goumri-Said, S. et al

in Thin Solid Films (2011), 519(10), 3283-3287

Thermochromic films of VO 2 were deposited by DC reactive magnetron sputtering on stainless steel substrate. Complex refractive indexes of VO 2 were determined by ellipsometric spectroscopy (0.35-16.5 μm ... [more ▼]

Thermochromic films of VO 2 were deposited by DC reactive magnetron sputtering on stainless steel substrate. Complex refractive indexes of VO 2 were determined by ellipsometric spectroscopy (0.35-16.5 μm) for different film thicknesses. Optical simulations were performed to model the spectral reflectance of the film/substrate system for a film thickness of 100 nm and 200 nm and to monitor the optical contrast of the thermochromic layers by comparing the spectral reflectance at 25 °C and 100 °C. The good agreement observed between experimental and theoretical spectra demonstrates the adequacy of the model for predicting the optical properties of the samples. © 2010 Elsevier B.V. All rights Reserved. [less ▲]

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See detailOptical Spectroscopy of Colliding-Wind Systems to be Observed with XMM
Sana, H.; Rauw, Grégor ULg; Gosset, Eric ULg et al

in Interacting Winds from Massive Stars (2002)

Not Available

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See detailOptical Spectroscopy of EZ Canis Majoris: Indication for Large-Scale Structures in a Wolf-Rayet Wind
Morel, Thierry ULg; St-Louis, Nicole; Marchenko, Sergey V

in Astrophysical Journal (1997), 482

We have carried out optical spectroscopy of the Wolf-Rayet star EZ CMa during 20 consecutive nights in 1995 January in support of the IUE Mega-project. In parallel with this optical spectroscopy, we also ... [more ▼]

We have carried out optical spectroscopy of the Wolf-Rayet star EZ CMa during 20 consecutive nights in 1995 January in support of the IUE Mega-project. In parallel with this optical spectroscopy, we also monitored EZ CMa using narrowband photometry. The light curve was found to be remarkably stable when folded with the P=3.77 day period, and it had a peak-to-valley amplitude of 0.1 mag. The P Cygni absorption components of He I lambda 3889 and He I lambda 5876 display a similar global pattern of variability as was found for the simultaneously acquired UV profiles. The strengthening of the P Cygni absorption component of these transitions is associated with the maximum of the continuum flux. Conversely, the absorption trough of N V lambda 4604 gradually disappears as the star brightens. Although the emission parts of the lines are variable at different levels, they all show the same pattern of variability, which consists of phase-dependent shifts of extra emission components superposed on the profiles. A strong correlation is found between the continuum-light level and the equivalent width of most transitions. The line skewness and the full-width at half-maximum show a daily recurrence timescale, reflecting the light curve changes. We have addressed in a rigorous statistical way the significance of the variations by calculating the "temporal variance spectrum." For any given line, we found enhanced variability at some velocities, although the whole profile displays a statistically significant level of variability. Arguments against a compact companion as the cause of the observed periodic variability are presented. Instead, our observations strongly support the suggestion in the IUE Mega analysis that the atypical level of variability results from the rotation of a structured wind. We propose that the wind variability of EZ CMa is triggered by photospheric activity, or that the wind is controlled by a large-scale magnetic field. [less ▲]

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See detailOptical Spectroscopy of EZ Canis Majoris: Indication for Large-Scale Structures in a Wolf-Rayet Wind
Morel, Thierry ULg; St-Louis, Nicole; Marchenko, Sergey V

in Astrophysical Journal (1997), 489

In the paper "Optical Spectroscopy of EZ Canis Majoris: Indication for Large-Scale Structures in a Wolf-Rayet Wind" by Thierry Morel, Nicole St-Louis, and Sergey V. Marchenko (ApJ, 482, 470 [1997]), there ... [more ▼]

In the paper "Optical Spectroscopy of EZ Canis Majoris: Indication for Large-Scale Structures in a Wolf-Rayet Wind" by Thierry Morel, Nicole St-Louis, and Sergey V. Marchenko (ApJ, 482, 470 [1997]), there are several errors that should be corrected. In the legends to Figures 3 and 6 and on page 483, 55% should read 99%. The revised version of Figure 12 given here replaces Figure 12 in the paper. [less ▲]

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See detailOptical Spectroscopy of the B and C Fragments of Comet 73P/Schwassmann-Wachmann 3 at the ESO VLT
Jehin, Emmanuel ULg; Manfroid, Jean ULg; Kawakita, H. et al

in LPI contribution 1405 (2008)

Not Available

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See detailOptical spectroscopy of X-Mega targets - II. The massive double-lined O-type binary HD 93205
Morrell, N. I.; Barbá, R. H.; Niemela, V. S. et al

in Monthly Notices of the Royal Astronomical Society (2001), 326

A new high-quality set of orbital parameters for the O-type spectroscopic binary HD 93205 has been obtained combining échelle and coudé CCD observations. The radial velocity orbits derived from the Heii ... [more ▼]

A new high-quality set of orbital parameters for the O-type spectroscopic binary HD 93205 has been obtained combining échelle and coudé CCD observations. The radial velocity orbits derived from the Heii lambda4686Å (primary component) and Hei lambda4471Å (secondary component) absorption lines yield semi-amplitudes of 133+/-2 and 314+/-2kms[SUP]-1[/SUP] for each binary component, resulting in minimum masses of 31 and 13M[SUB]solar[/SUB] (q=0.42). We also confirm for the binary components the spectral classification of O3V+O8V previously assigned. Assuming for the O8V component a `normal' mass of 22-25M[SUB]solar[/SUB] we would derive for the primary O3V a mass of `only' 52-60M[SUB]solar[/SUB] and an inclination of about 55° for the orbital plane. We have also determined for the first time a period of apsidal motion for this system, namely 185+/-16yr using all available radial velocity data sets of HD 93205 (from 1975 to 1999). Phase-locked variations of the X-ray emission of HD 93205 consisting of a rise of the observed X-ray flux near periastron passage are also discussed. [less ▲]

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