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See detailMeasurements of long-term changes in atmospheric OCS (carbonyl sulfide) from infrared solar observations
Rinsland, Curtis P.; Chiou, Linda S.; Mahieu, Emmanuel ULg et al

in Journal of Quantitative Spectroscopy & Radiative Transfer (2008), 109(16), 2679-2686

Multi-decade atmospheric OCS (carbonyl sulfide) infrared measurements have been analyzed with the goal of quantifying long-term changes and evaluating the consistency of the infrared atmospheric OCS ... [more ▼]

Multi-decade atmospheric OCS (carbonyl sulfide) infrared measurements have been analyzed with the goal of quantifying long-term changes and evaluating the consistency of the infrared atmospheric OCS remote-sensing measurement record. Solar-viewing grating spectrometer measurements recorded in April 1951 at the Jungfraujoch station (46.5°N latitude, 8.0°E longitude, 3.58 km altitude) show evidence for absorption by lines of the strong ν3 band of OCS at 2062 cm(−1). The observation predates the earliest previously reported OCS atmosphere remote-sensing measurement by two decades. More recent infrared ground-based measurements of OCS have been obtained primarily with high-resolution solar-viewing Fourier transform spectrometers (FTSs). Long-term trends derived from this record span more than two decades and show OCS columns that have remained constant or have decreased slightly with time since the Mt. Pinatubo eruption, though retrievals assuming different versions of public spectroscopic databases have been impacted by OCS ν3 band line intensity differences of 10%. The lower stratospheric OCS trend has been inferred assuming spectroscopic parameters from the high-resolution transmission (HITRAN) 2004 database. Volume mixing ratio (VMR) profiles measured near 30°N latitude with high-resolution solar-viewing FTSs operating in the solar occultation mode over a 22 years time span were combined. Atmospheric Trace MOlecucle Spectroscopy (ATMOS) version 3 FTS measurements in 1985 and 1994 were used with Atmospheric Chemistry Experiment (ACE) measurements during 2004–2007. Trends were calculated by referencing the measured OCS VMRs to those of the long-lived constituent N2O to account for variations in the dynamic history of the sampled airmasses. Means and 1-sigma standard deviations of VMRs (in ppbv, or 10−9 per unit air volume) averaged over 30–100 hPa from measurements at 25–35°N latitude are 0.334±0.089 ppbv from 1985 (ATMOS Spacelab 3 measurements), 0.297±0.094 ppbv from 1994 ATLAS 3 measurements, 0.326±0.074 ppbv from ACE 2004 measurements, 0.305±0.096 ppbv from ACE 2005 measurements, 0.328±0.074 from ACE 2006 measurements, and 0.305±0.090 ppbv from ACE measurements through August 2007. Assuming these parameters, we conclude that there has been no statistically significant trend in lower stratospheric OCS over the measurement time span. We discuss past measurement sets, quantify the impact of changes in infrared spectroscopic parameters on atmospheric retrievals and trend measurements, and discuss OCS spectroscopic uncertainties of the current ν3 band parameters in public atmospheric databases. [less ▲]

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See detailMeasurements of mediator cascades during adult respiratory distress syndrome
Lamy, Maurice ULg; Deby-Dupont, G.; Deby, C. et al

in Adult Respiratory Distress Syndrome (1992)

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See detailMeasurements of microbial N flow to the duodenum and urinary excretion of purine derivatives in bulls.
Beckers, Yves ULg; Thewis, André ULg; Sohy, Christophe et al

in Annales de Zootechnie (1995), 44

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See detailMeasurements of non-Rutherford cross sections for 4-15 MeV alpha particles on light elements from C to Si
Chene, Grégoire ULg; Mathis, François ULg; Fleury-Frenette, Karl ULg et al

Conference (2013, September)

These last years Ion Beam Analysis users show an interest in High Energy Alpha beams[1]. These beams can be used for on-site analysis by means of radioactive sources e.g. for space application but they ... [more ▼]

These last years Ion Beam Analysis users show an interest in High Energy Alpha beams[1]. These beams can be used for on-site analysis by means of radioactive sources e.g. for space application but they also offer a powerful combination of properties for the analysis of thick layers (about 10 to 20 µm). This kind of layers is often met in cultural heritage applications but can be also present on new materials. Contrary to this kind of materials where the principal information needed is the in-depth profiles as the sample are of known composition, for cultural heritage materials the combination of elemental analysis and their in-depth distribution is essential as the nature of the material is a-priori not known. In this perspective high energy alpha beams can produce really interesting results as their PIXE cross-sections increase from 6 MeV while the lower penetration of the beam (comparing to classical protons beams) allows to limit the analysis to the layer of interest. For the elemental in depth distribution we take advantage of the good mass separation of the alpha particles and the non-Rutherford phenomena allow the analysis even of light elements which are of great interest in cultural heritage problematic as far as the cross section are well tabulated. Using two IBA facilities (AGLAE in Paris and the HE-HR beam line of the cyclotron in Liège University[2]) we explored the backscattering cross section of numerous light elements (from C to Si) from 4 to 15 MeV in order to check the lack in the literature, to verify the deviation from Rutherford law and compare it to the existing theoretical models. We begin to measure the needed cross sections using thick target in case of smooth cross section and thin layers for exploring important variation of the cross section. [less ▲]

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See detailMeasurements of the 14N/15N isotopic ratio in comets's ammonia
Rousselot, P.; Pirali, O.; Jehin, Emmanuel ULg et al

Conference (2014, May)

La détermination des rapports isotopiques de l'azote dans les différents objets du système solaire est importante pour une bonne compréhension de leur origine. Les mesures du rapport 14N/15N faites jusqu ... [more ▼]

La détermination des rapports isotopiques de l'azote dans les différents objets du système solaire est importante pour une bonne compréhension de leur origine. Les mesures du rapport 14N/15N faites jusqu'à présent ont montré une grande dispersion des valeurs (de 50 à 441), tous les objets du système solaire excepté Jupiter apparaissant enrichis en 15N comparés à la nébuleuse protosolaire. Différentes explications ont été proposées pour expliquer les valeurs observées, qui sont complexes à interpréter car dues non seulement au réservoir d'origine de l'azote d'où provient l'objet étudié mais également à des mécanismes de fractionnement isotopique. Le cas des comètes, dans ce contexte, est intéressant, car leur composition est supposée relativement proche de celle de la nébuleuse protosolaire et la seule valeur disponible jusqu'à l'année dernière, avait été calculée à partir de la molécule HCN et du radical CN (issu du HCN). Ce rapport était d'environ 150, bien en dessous de la valeur mesurée dans l'atmosphère terrestre (272). Les comètes contiennent beaucoup d'azote sous forme de NH3, photodissocié en NH2 dont les raies sont nombreuses dans le spectre visible. Il était donc possible de mesurer le rapport 14N/15N dans l'ammoniac pour vérifier l'influence possible de phénomènes de fractionnement isotopique entre le HCN et le NH3, ceci à condition de connaître avec précision les longueurs d'onde des raies de 15NH2. Pour déterminer ces longueurs d'onde, nous avons mesuré le spectre d'émission de la transition Ã2A1~X2B1 de 14NH2 et 15NH2 dans la gamme spectrale 5700 Å – 6000 Å sur la ligne AILES du synchrotron SOLEIL, avec un spectromètre par transformée de Fourier. L'analyse de ces spectres a permis, au final, la détection du 15NH2 dans les spectres cométaires et la première détermination du rapport 14N/15N dans l'ammoniac des comètes. [less ▲]

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See detailMeasurements of the ground state ionization energy and wavelengths for the 1snp1P1 - 1s2 1S0(n=4-10) lines of O VII
Bartnik, A.; Biémont, Emile ULg; Dyakin, V. M. et al

in Journal of Physics : B Atomic Molecular & Optical Physics (1997), 30

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See detailMeasurements of the ground state ionization energy and wavelengths for the nl-nl' transitions of Ni XIX (n=4-15) and Ge XXIII (n=7-9)
Biémont, Emile ULg; Magunov, A. I.; Dyakin, V. M. et al

in Journal of Physics : B Atomic Molecular & Optical Physics (2000), 33

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See detailMeasurements of the ground-state ionization energy and wavelengths for the 1snp P-1(1)*-1s(2) S-1(0) (n=4-9) lines of Mg XI and FVIII
Pal'chikov, V. G.; Faenov, A. Y.; Skobelev, I. Y. et al

in Journal of Physics B-Atomic Molecular and Optical Physics (2002), 35(12), 2741-2754

The wavelengths of the 1snp P-1(1)0-1s(2) S-1(0) transitions in the He-like Mg XI (n = 4-9) and F VIII (n = 4-8) have been measured in laser-produced plasmas. The accuracy of the present measurements (0.4 ... [more ▼]

The wavelengths of the 1snp P-1(1)0-1s(2) S-1(0) transitions in the He-like Mg XI (n = 4-9) and F VIII (n = 4-8) have been measured in laser-produced plasmas. The accuracy of the present measurements (0.4-1.6 mAngstrom) is a large improvement over previous results. The Rydberg series is used to determine the ground-state ionization energy of F VIII and Mg XI: E-ion (F VIII) = 953.96 +/- 0.11 eV, E-ion (Mg XI) = 1761.88 +/- 0.15 eV. These experimental results are compared with theoretical data calculated by the 1/Z-expansion method and the HFR and MCDF approaches. Fairly good agreement between theory and experiment is observed with a precision up to 5 x 10(-5). Radiative corrections to the 1s(2) S-1(0) state are analysed and compared with experiments. It is found that QED corrections to the ground-state ionization energy are significant at the present level of experimental accuracy. [less ▲]

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See detailMeasurements of the helium 584 Å airglow during the Cassini flyby of Venus
Gérard, Jean-Claude ULg; Gustin, Jacques ULg; Hubert, Benoît ULg et al

in Planetary and Space Science (2011), 59

The helium resonance line at 584 Å has been observed with the UltraViolet Imaging Spectrograph (UVIS) Extreme Ultraviolet channel during the flyby of Venus by Cassini at a period of high solar activity ... [more ▼]

The helium resonance line at 584 Å has been observed with the UltraViolet Imaging Spectrograph (UVIS) Extreme Ultraviolet channel during the flyby of Venus by Cassini at a period of high solar activity. The brightness was measured along the disk from the morning terminator up to the bright limb near local noon. The mean disk intensity was ˜320 R, reaching ˜700 R at the bright limb. These values are slightly higher than those determined from previous observations. The sensitivity of the 584 Å intensity to the helium abundance is analyzed using recent cross-sections and solar irradiance measurements at 584 Å. The intensity distribution along the UVIS footprint on the disk is best reproduced using the EUVAC solar flux model and the helium density distribution from the VTS3 empirical model. It corresponds to a helium density of 8×10[SUP]6[/SUP] cm[SUP]-3[/SUP] at the level of where the CO[SUB]2[/SUB] is 2×10[SUP]10[/SUP] cm[SUP]-3[/SUP]. [less ▲]

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See detailMeasurements Of The Horizontal Sprayer Boom Movements By Sensor Data Fusion
Ooms, David ULg; Lebeau, Frédéric ULg; Ruter, R. et al

in Computers and Electronics In Agriculture (2002), 33(2),

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See detailMeasurements of thermal effects in a bulk YBCO single domain superconductor submitted to a variable magnetic field
Laurent, Philippe ULg; Vanderbemden, Philippe ULg; Meslin, S. et al

in IEEE Transactions on Applied Superconductivity (2007), 17(2, Part 3), 3036-3039

When YBCO single domains are subjected to a variable magnetic field, the motion of vortices may give rise to a significant temperature increase and a degradation of the superconducting properties. We have ... [more ▼]

When YBCO single domains are subjected to a variable magnetic field, the motion of vortices may give rise to a significant temperature increase and a degradation of the superconducting properties. We have experimentally investigated such effects in bulk melt-processed YBCO single domains. Several temperature sensors, a pick-up coil and two Hall probes were placed against the surface of a monolithic bulk YBCO pellet. Data were simultaneously recorded during the application of ac magnetic fields of various amplitudes, either with or without a pre-existing dc trapped flux. The measurement results agree well with to those obtained by numerical modeling. It was also found that a superimposed dc magnetic moment reduces the temperature increase caused by the ac magnetic field. (C) 2003 IEEE. [less ▲]

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See detailMeasurements of total respiratory impedance in dogs during nasal obstruction by the forced oscillation method
Clercx, Cécile ULg; Gustin, Pascal ULg; Lekeux, Pierre ULg et al

in 7th Comparative Respiratory Society Meeting - Liège - Belgique (1989)

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See detailMeasurements of urinary COLL2-1NO2 is predictif of joint space narrowing in knee osteoarthritis
Henrotin, Yves ULg; Kraus, V.; Brandt, K.D. et al

in Osteoarthritis and Cartilage (2011)

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See detailMeasurements of Vitamin D Do Not Necessarily Reflect What You Give to Your Patients
Cavalier, Etienne ULg; Cormier, Catherine; Souberbielle, Jean-Claude

in Journal of Bone and Mineral Research (2008, September), 23

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See detailMeasurements on magnetized GdBCO pellets subjected to small transverse ac magnetic fields at very low frequency: Evidence for a slowdown of the magnetization decay
Fagnard, Jean-François ULg; Kirsch, Sébastien; Morita, Mitsuru et al

in Physica C: Superconductivity (2015), 512

Due to their ability to trap large magnetic inductions, superconducting bulk materials can be used as powerful permanent magnets. The permanent magnetization of such materials, however, can be ... [more ▼]

Due to their ability to trap large magnetic inductions, superconducting bulk materials can be used as powerful permanent magnets. The permanent magnetization of such materials, however, can be significantly affected by the application of several cycles of a transverse variable magnetic field. In this work, we study, at T = 77 K, the long term influence of transverse ac magnetic fields of small amplitudes (i.e. much smaller than the full penetration field) on the axial magnetization of a bulk single grain superconducting GdBCO pellet over a wide range of low frequencies (1 mHz–20 Hz). Thermocouples are placed against the pellet surface to probe possible self-heating of the material during the experiments. A high sensitivity cryogenic Hall probe is placed close to the surface to record the local magnetic induction normal to the surface. The results show first that, for a given number of applied triangular transverse cycles, higher values of dBapp/dt induce smaller magnetization decays. An important feature of practical interest is that, after a very large number of cycles which cause the loss of a substantial amount of magnetization (depending on the amplitude and the frequency of the field), the rate of the magnetization decay goes back to its initial value, corresponding to the relaxation of the superconducting currents due to flux creep only. In the amplitude and frequency range investigated, the thermocouples measurements and a 2D magneto-thermal modelling show no evidence of sufficient self-heating to affect the magnetization so that the effect of the transverse magnetic field cycles on the trapped magnetic moment is only attributed to a redistribution of superconducting currents in the volume of the sample and not to a thermal effect. [less ▲]

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See detailMeasures of mastitis
Detilleux, Johann ULg; Kehrli, M.E.Jr.; Freeman, A. E. et al

(1996)

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See detailMeasuring 25-hydroxyvitamin D: where are we standing in 2013?
CAVALIER, Etienne ULg

Conference (2013, March 27)

Detailed reference viewed: 16 (1 ULg)
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See detailMeasuring a conceptual model of early turnover : a longitudinal perspective.
Bertrand, Françoise ULg; Schreurs, B.; Hansez, Isabelle ULg

Conference (2008, January 11)

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See detailMeasuring a conceptual model of military turnover : a longitudinal perspective.
Bertrand, Françoise ULg; Schreurs, B.; Lescreve, F. J. et al

Conference (2007, May 12)

Detailed reference viewed: 16 (0 ULg)