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See detailExperimental and theoretical investigation of the lamellar structure of a styrene-butyl methacrylate diblock copolymer by fluorescence resonance energy transfer, small-angle X-ray scattering, and self-consistent-field simulations
Spiro, John G; Yang, Jiahn; Zhang, Jian-Xin et al

in Macromolecules (2006), 39(20), 7055-7063

We have investigated the repeat distance and interface thickness, at 160 degrees C, of a poly(styrene-b-butyl methacrylate) (PS-b-PBMA) diblock copolymer of similar to 180 000 molecular weight by small ... [more ▼]

We have investigated the repeat distance and interface thickness, at 160 degrees C, of a poly(styrene-b-butyl methacrylate) (PS-b-PBMA) diblock copolymer of similar to 180 000 molecular weight by small- angle X-ray scattering (SAXS) and fluorescence resonance energy transfer ( FRET). We have found a lamellar period of 47 nm and an interface thickness of 5 nm. A simple, hyperbolic secant model of the junction distribution appeared to be sufficient to analyze the fluorescence decay data on the junction-labeled polymer containing different acceptor/donor ratios, but simulations based on a numerical self- consistent-field (NSCF) formalism also allowed us to find a range of approximately 0.017-0.018 for the Flory-Huggins interaction parameter (chi(FH), defined with reference to the monomeric volume of polystyrene) and a PBMA Kuhn length (b(PBMA)) of 0.65-0.67 nm. We note that earlier values of chi(FH) and b(PBMA) reported in the literature vary considerably. The NSCF computations suggest that even modest levels of conformational asymmetry perturb the block copolymer morphology. A weakness of our theoretical (NSCF) approach is the compressible nature of PS-b-PBMA. However, lattice cluster, equation of state (EOS), or other models that allow for compressibility have not yet been developed to the level of sophistication needed to predict block copolymer repeat distances or interface thicknesses. Indeed, as detailed in the Supporting Information, current EOS methods leave much to be desired even in predicting the phase transitions of lower molecular weight PS-b-PBMA samples. [less ▲]

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See detailExperimental and theoretical investigations of the electrical properties of undoped and magnesium-doped GaN layers
Nguyen, Ngoc Duy ULg; Germain, Marianne; Schmeits, Marcel et al

in Journal of Crystal Growth (2001), 230

The ac characteristics of GaN : Mg and undoped GaN layers, grown by MOVPE on sapphire substrates, are measured for a wide range of temperature and bias conditions, in order to investigate the effect of ... [more ▼]

The ac characteristics of GaN : Mg and undoped GaN layers, grown by MOVPE on sapphire substrates, are measured for a wide range of temperature and bias conditions, in order to investigate the effect of the magnesium-related level on the transport properties. Two peaks, whose height and position depend on the measurement temperature, are observed in the admittance curves (G/ω versus frequency) of the Mg-doped samples, whereas only one peak appears in undoped samples. The study of the frequency dependence of the impedance, with a model including the two metallic Au/GaN junctions, the GaN layer itself, shows that, besides the effect of the differential resistance of the layer which plays a role in both sample types, the presence of a Mg-related deep level contributes to the observed variations of the peaks in the admittance curves of the p-doped samples. Results of a theoretical steady-state and small-signal analysis based on numerical modelling of the Au/GaN/Au heterostructure complete our analysis. [less ▲]

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See detailExperimental and theoretical investigations of the electrical properties of undoped and magnesium-doped GaN layers
Nguyen, Ngoc Duy ULg; Germain, Marianne; Schmeits, Marcel et al

Conference (2000)

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See detailExperimental and theoretical lifetimes and transition probabilities in Sb I
Hartman, H; Nilsson, H; Engström, L et al

in Physical Review. A (2010), 82

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See detailExperimental and theoretical lifetimes in Yb III
Zhang, Z. G.; Li, Z. S.; Svanberg, S. et al

in European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2001), 15

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See detailExperimental and theoretical radiative decay rates for highly excited ruthenium atomic levels and the solar abundance of ruthenium
Fivet, V.; Quinet, Pascal ULg; Palmeri, P. et al

in Monthly Notices of the Royal Astronomical Society (2009), 396

The solar photospheric abundance of ruthenium is revised on the basis of a new set of oscillator strengths derived for Ru I transitions with wavelengths in the spectral range 2250–4710 Å. The new ... [more ▼]

The solar photospheric abundance of ruthenium is revised on the basis of a new set of oscillator strengths derived for Ru I transitions with wavelengths in the spectral range 2250–4710 Å. The new abundance value (in the usual logarithmic scale where the solar hydrogen abundance is equal to 12.00), ARu = 1.72 ± 0.10, is in agreement with the most recent meteoritic result, ARu = 1.76 ± 0.03. The accuracy of the transition probabilities, obtained using a relativistic Hartree–Fock model including core-polarization effects, has been assessed by comparing the theoretical lifetimes with previous experimental results. A comparison is also made with new measurements performed in this work by the time-resolved laser-induced fluorescence spectroscopy for 10 highly excited odd-parity levels of Ru I [less ▲]

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See detailExperimental and theoretical radiative lifetimes, branching fractions, and oscillator strengths for Lu I and experimental lifetimes for Lu II and Lu III
Fedchak, J. A.; Den Hartog, E. A.; Lawler, J. E. et al

in Astrophysical Journal (2000), 542

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See detailExperimental and theoretical radiative properties of odd-parity highly excited levels in Mo II
Jiang, L; Wang, Q; Feng, Y et al

in European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2012), 66

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See detailExperimental and theoretical radiative properties of odd-parity highly excited levels in Mo II
Jiang, L; Wang, Q; Feng, Y et al

in European Physical Journal D -- Atoms, Molecules, Clusters & Optical Physics (2012), 66

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See detailExperimental and theoretical studies of DyIII: radiative lifetimes and oscillator strengths of astrophysical interest
Zhang, Z. G.; Svanberg, S.; Palmeri, P. et al

in Monthly Notices of the Royal Astronomical Society (2002), 334(1), 1-10

The lifetimes of three short-lived levels belonging to the 4f(9) 6p configuration and of two long-lived levels of the 4f(9) 5d configuration of Dy iii have been measured for the first time using time ... [more ▼]

The lifetimes of three short-lived levels belonging to the 4f(9) 6p configuration and of two long-lived levels of the 4f(9) 5d configuration of Dy iii have been measured for the first time using time-resolved laser-induced fluorescence techniques. They are in good agreement with theoretical values calculated within the framework of a pseudo-relativistic configuration interaction approximation. Using the experimental lifetimes and the theoretical branching fractions, a first set of transition probabilities of astrophysical interest has been obtained for Dy III. [less ▲]

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See detailExperimental and theoretical studies suggesting the possibility of metallic boron nitride edges in porous nanourchins
Terrones, M.; Charlier, Jean-Christophe; Gloter, A. et al

in Nano Letters (2008), 8(4), 1026-1032

We first describe the synthesis of novel and highly porous boron nitride (BN) nanospheres (100–400 nm o.d.) that exhibit a rough surface consisting of open BN nanocones and corrugated BN ribbons. The ... [more ▼]

We first describe the synthesis of novel and highly porous boron nitride (BN) nanospheres (100–400 nm o.d.) that exhibit a rough surface consisting of open BN nanocones and corrugated BN ribbons. The material was produced by reacting B2O3 with nanoporous carbon spheres under nitrogen at ca. 1750 °C. The BN nanospheres were characterized using scanning electron microscopy, high-resolution electron microscopy, and electron energy loss spectroscopy. The porous BN spheres show relatively large surface areas of ca. 290 m2/g and exhibit surprisingly stable field emission properties at low turn-on voltages (e.g., 1–1.3 V/µm). We attribute these outstanding electron emission properties to the presence of finite BN ribbons located at the surface of the nanospheres (exhibiting zigzag edges), which behave like metals as confirmed by first-principles calculations. In addition, our ab initio theoretical results indicate that the work function associated to these zigzag BN ribbons is 1.3 eV lower when compared with BN-bulk material. [less ▲]

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See detailExperimental and theoretical transition probabilities in singly ionized gold
Biémont, Emile ULg; Blagoev, K.; Fivet, V. et al

in Monthly Notices of the Royal Astronomical Society (2007), 380(4), 1581-1588

Absolute transition probabilities have been measured for lines originating from the 5d(9)6d and 5d(9)7s electronic configurations in the spectrum of singly ionized gold (Au II). The laser-induced ... [more ▼]

Absolute transition probabilities have been measured for lines originating from the 5d(9)6d and 5d(9)7s electronic configurations in the spectrum of singly ionized gold (Au II). The laser-induced breakdown spectroscopy has been applied to free gold atoms and ions produced by laser ablation. Absolute transition probabilities have been determined using the branching fraction and the Boltzmann plot methods. Theoretical branching fractions as well as radiative lifetime values have also been obtained by a relativistic Hartree-Fock method taking core polarization and configuration interaction effects into account. The new results are compared with previous results when available. [less ▲]

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See detailExperimental anti-angiogenesis causes upregulation of genes associated with poor survival in glioblastoma.
Saidi, Ahlame; Javerzat, Sophie; Bellahcene, Akeila ULg et al

in International Journal of Cancer = Journal International du Cancer (2008), 122(10), 2187-98

Vascular endothelial growth factor (VEGF) inhibitors are the most promising anti-angiogenic agents used increasingly in the clinic. However, to be efficient, anti-VEGF agents need to be associated with ... [more ▼]

Vascular endothelial growth factor (VEGF) inhibitors are the most promising anti-angiogenic agents used increasingly in the clinic. However, to be efficient, anti-VEGF agents need to be associated with classic chemotherapy. Exploring gene regulation in tumor cells during anti-angiogenesis might help to comprehend the molecular basis of response to treatment. To generate a defined anti-angiogenic condition in vivo, we transfected human glioma cells with short-interfering RNAs against VEGF-A and implanted them on the chick chorio-allantoic membrane. Gene regulation in avascular tumors was studied using human Affymetrixtrade mark GeneChips. Potentially important genes were further studied in glioma patients. Despite strong VEGF inhibition, we observed recurrent formation of small, avascular tumors. CHI3L2, IL1B, PI3/elafin and CHI3L1, which encodes for YKL-40, a putative prognosticator for various diseases, including cancer, were strongly up-regulated in avascular glioma. In glioblastoma patients, these genes showed coregulation and their expression differed significantly from low-grade glioma. Importantly, high levels of CHI3L1 (p = 0.036) and PI3/elafin mRNA (p = 0.0004) were significantly correlated with poor survival. Cox regression analysis further confirmed that PI3 and CHI3L1 levels are survival markers independent from patient age and sex. Elafin-positive tumor cells were only found in glioblastoma, where they were clustered around necrotic areas. PI3/elafin is strongly induced by serum deprivation and hypoxia in U87 glioma cells in vitro. Our results indicate that anti-angiogenesis in experimental glioma drives expression of critical genes which relate to disease aggressiveness in glioblastoma patients. In particular, CHI3L1 and PI3/elafin may be useful as new prognostic markers and new therapeutic targets. [less ▲]

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See detailAn experimental approach for synthesis of Fe-Al-O multiferroic fibrous material
Starbov, N; Starbova, K; Vanderbemden, Philippe ULg et al

in Journal of Physics: Conference Series (2012), 398

Basic principles of the electro-hydrodynamics are applied for synthesis of solid state Fe-Al-O multi-ferroic fibrous material. For that purpose stable blend spinning solutions comprised of a high ... [more ▼]

Basic principles of the electro-hydrodynamics are applied for synthesis of solid state Fe-Al-O multi-ferroic fibrous material. For that purpose stable blend spinning solutions comprised of a high molecular assisting organic polymer and salts of iron and aluminum are developed. These solutions are tested under electrospinning conditions and synthesis of homogeneous as spun non-woven mats characterized by fibre mean diameters in the microand nano-size range is successfully demonstrated. Multi-step thermal procedure is applied for the consecutive solvent evaporation, polymer pyrolisis and final fibre calcination. Electronoptical imaging technique and XRD are applied for revealing the sample morphology and the phase composition correspondingly. The results obtained outline the wide possibilities for fabrication of multi-ferroics fibrous nano-materials on the basis of Fe-Al-O. [less ▲]

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See detailExperimental approach of the behavioural spawning tactics in Barbus meridionalis using paternity analysis.
Binda, O.; Poncin, Pascal ULg; Chenuil, A. et al

Poster (1997)

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See detailAn Experimental Approach to Link Powder Physical Properties to 3D Particle Shape
Califice, Arnaud ULg; Lumay, Geoffroy ULg; Vandewalle, Nicolas ULg et al

in Particulate Systems Analysis 2011 (2011, September)

A series of samples have been characterized by 3D image analysis (using X-Ray microtomography). The samples consist of blends of metallic particles: steel shot abrasives (“balls”), steel fibres and ... [more ▼]

A series of samples have been characterized by 3D image analysis (using X-Ray microtomography). The samples consist of blends of metallic particles: steel shot abrasives (“balls”), steel fibres and angular steel grit particles. The blends were systematically prepared in different proportions of the raw products. Various shape and size parameters were measured on the particles: equivalent volume diameter (dV), maximum inscribed sphere diameter (dIN), particle length (maximum Feret diameter), particle elongation (El), particle flatness (Fl) etc. The results are expressed as statistical shape and size parameters, expressed both as volume and number weighted distributions. The blends have been tested for compaction using a cylindrical container which experiences a series of 500 free falls over a height of 3mm. The compaction dynamics was monitored using a sensor that measures the evolution of the solid volume fraction as a function of the tap number. From the obtained compaction curve, the Hausner ratio and a flowability index were extracted. The same blends have also been analysed using a rotating drum at different rotation speeds to analyze the evolution of the flowing angle. As the system is based on the analysis of a time sequence of 50 images (separated by 0.5 sec) it is possible to measure the intermittent character of the powder flow. The resulting measure is a cohesive index of the powder. The results obtained from physical testing were systematically plotted as a function of various statistical indices of the shape and size distributions in order to reveal correlations between particle shape properties and physical behaviour. Some clear trends appeared, demonstrating the influence of particle shape on powder physical properties. [less ▲]

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See detailExperimental assement of the effect of the real flame emissivity for steel elements engulfed into fire
Tondini, Nicola; Vassart, Olivier; Franssen, Jean-Marc ULg

in xxx (in press)

This paper presents the results of an experimental campaign performed to assess the effect of the flame emissivity for steel members engulfed into fire. In detail, two sizes of circular steel tubes were ... [more ▼]

This paper presents the results of an experimental campaign performed to assess the effect of the flame emissivity for steel members engulfed into fire. In detail, two sizes of circular steel tubes were engulfed into pool fires of two different diameters. Two fuels were used and for both fuels tests without column (used as comparison with existing localised fire models) and with column were performed. The temperature of the column and of the flames were measured at different heights. The width of the flame was also measured and used to calculate the emissivity of the flame the value of which was employed in numerical simulations in order to predict the evolution of the temperature of the steel column. Comparison with numerical analyses where the recommended values of the Eurocode were used is also shown. [less ▲]

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See detailEXPERIMENTAL CHALLENGES TO THE STANDARD MODEL: A REEVALUATION
Cudell, Jean-René ULg

Doctoral thesis (1987)

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