Search

Moreover, in treatment-naïve patients receiving zanubrutinib, obinutuzumab and venetoclax, achieving a 2.6 log-reduction (400-fold) in MRD between baseline and cycle 5 was predictive of reaching undetectable MRD at cycle 8 and retaining MRD < 10 SP -5 sp after 1 year of treatment cessation [[9]]. In conclusion, in treatment-naïve CLL patients treated with venetoclax and obinutuzumab, high levels of early MRD (>10 SP -2 sp ) and a slow rate of MRD eradication, measured after 11 weeks of treatment, predicted failure to reach uMRD (<10 SP -5 sp ) at the end of induction treatment. Dear Editor, Measurable residual disease (MRD) is an important post-treatment biomarker that predicts progression-free survival (PFS) following fixed-duration treatment in chronic lymphocytic leukemia (CLL) [[1]]. Patients reaching MRD < 10 SP -5 sp at EOiT had higher MRD, compared to patients that failed to reach MRD < 10 SP -5 sp (mean MRD 5.1 versus 2.9, I P i = 0.02). [Extracted from the article]

We present a new niche application of quasicrystalline powders that leads to a commercially successful development of polymer-matrix composites. The process is based upon selective laser sintering, which is one of the current most powerful additive manufacturing technologies in use in the mechanical industries. Characteristics of the materials produced, such as porosity, friction and wear against hard steel, are evaluated and compared to the state of the art. Insight into the production of metal-matrix composites, using a variant of the technology, is also given. [ABSTRACT FROM AUTHOR]

A first principle study of lead adsorption on the pseudo-10-fold surface of the orthorhombic Al13Co4 intermetallic compound has been performed using four possible structural models as substrate. Coverage between atomic adsorption to near 0.08 atm./Å2 has been considered. Relative adsorption energies of Pb atoms on different surface sites in addition with simulated scanning tunneling microscopy images were obtained for each model. Our ab initio calculations demonstrate that the experimental results published recently, highlighting (i) the presence of a preferential adsorption site and (ii) the formation of Pb rows extending along the [010] direction [ N. J. Phys. 2011, 13, 10301114] can be only reproduced using a dense Al-rich termination as the substrate structural model. This result confirms the previously established structural model for the (100) surface of orthorhombic Al13Co4 [ Phys. Rev. B 2011, 84, 085411]. This study then provides an understanding of the experimental observations for the different lead coverages. © 2012 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

We have investigated the adsorption of Pb atoms on the (100) surface of an orthorhombic Al13Co4 crystal at 300 and 573K substrate temperatures. This complex metallic alloy is an approximant to the decagonal Al-Ni-Co quasicrystal. At submonolayer coverage and at 300 K, Pb adatoms remain highly mobile and adsorb preferentially within the hollow site situated in between adjacent Al pentagonal clusters present at the surface. These experimental findings are supported by ab initio calculations based on density functional theory (DFT). For both temperature regimes, Pb adsorption leads to the formation of pseudomorphic monolayers above which the high adsorbate mobility prohibits the growth of additional layers. For the high-temperature deposition, we propose a structural model for the Pb film and discuss its relationship with the underneath substrate. [ABSTRACT FROM AUTHOR]

The atomic and electronic structures of the (100) and (001) surfaces of the Al5Co2 complex metallic alloy are studied by ab initio calculations. The relative stability of the possible surface planes built from bulk truncation is calculated and the influence of the atomic surface density, the interlayer spacing and the surface chemical composition on the plane selection is discussed. In addition, we show that the simulated images of scanning tunnelling microscopy for each possible termination present a specific signature that appears to be sufficient to experimentally identify the surface plane. [ABSTRACT FROM AUTHOR]

The structure of the valence bands in a number of complex alloys was investigated using X-ray emission spectroscopy, focusing on the distribution of d-like states in a series of Al- and Mg-based alloys. A substantial density of d-like states was found at or just under the Fermi level in the Al s,d and Mg s,d distributions of these complex systems. It is suggested that d-like states play a significant role in local symmetry of the crystals and contribute to selecting and stabilizing their structures. [ABSTRACT FROM AUTHOR]

Although the industrial development of complex metallic alloys (CMAs) and quasicrystals (QCs) has remained quite limited so far, these materials exhibit interesting and sometimes unexpected properties in terms of technological applications. A few selected examples of the most promising properties and trends for potential applications are presented. [ABSTRACT FROM AUTHOR]

Twenty-five years after the historic discovery of a real material exhibiting fivefold symmetry, the scientific field opened as a result is still robust and active. On the experimental side, it has been strengthened in recent years by new inputs coming from studies of transport properties, surface physics, coating technology, catalysis, etc. Its future probably relies upon combining these very exotic, but now extremely well documented materials with more conventional materials in composites, or challenging the discovery of new, or more exciting properties in a systematic screening of intermetallics compounds with untried compositions. An effort towards making quasicrystals better understood outside our own community has become mandatory with a view to developing the field. [ABSTRACT FROM AUTHOR]

We report on the formation of a new crystalline approximant phase of the icosahedral (i-)Al-Cu-Fe quasicrystal. This phase is formed during sintering of Al-based composites reinforced with i-AlCuFeB quasicrystalline particles. The structure of this phase has been characterized by transmission electron microscopy (TEM) and high-resolution electron microscopy (HREM). TEM revealed that it is a B-centred orthorhombic phase with lattice parameters a = 1.166 nm, b = 1.195 nm and c = 3.44 nm. Its chemical composition, as determined by electron energy loss spectroscopy (EELS), is close to Al76.9Cu2.7Fe20.4, with an average number of valence electrons per atom e/a of 1.92, similar to the value in all other approximants of the i-phase discovered thus far. Initial results on local atomic arrangements along one of its pseudo-5-fold axes are also presented. [ABSTRACT FROM AUTHOR]

Al-based composites reinforced by icosahedral (i-) Al59Cu25.5Fe12.5B3 quasicrystalline particles were prepared by solid-state sintering. It was found that Al diffusion from the matrix to the quasicrystalline particles induces phase transformation into the ω-Al7Cu2Fe tetragonal phase. In order to preserve the i phase, we used an oxidation pre-treatment of the particles and studied its influence on the kinetics of the phase transformation (Al + i → ω) as a function of temperature by high energy X-ray diffraction. The oxide layer acts as a barrier, reducing efficiently the diffusion of Al up to a sintering temperature of 823 K, allowing the control of the phases in the composites. The mechanical properties and the friction behaviour of the composites were investigated and show the negative influence of the oxide on the interface strength. [ABSTRACT FROM AUTHOR]

This paper reports a vacuum or space related effect, which is referred to as “cold welding”, “adhesion” or “sticking”. This effect is studied for bulk quasicrystal (J.M. Dubois, Useful Quasicrystals (World Scientific, Singapore, 2005)) versus different kinds of counterparts (steel, aluminium, titanium, hard metals). Full series of samples, prepared either by crystal-pulling techniques (single crystals) or by sintering (multi-grain samples) were analysed by fretting tests. Four alloy systems were investigated: Al–Pd–Mn, Al–Cr–Fe–B, Al–Cu–B and Al–Cu–Fe–B, with different crystallographic structures and nominal compositions. These materials, especially icosahedral phases, exhibit the absence of cold-welding in vacuum versus certain steels. [ABSTRACT FROM AUTHOR]

Wetting of micron-sized Pb droplets on thin polycrystalline films of decagonal Al 13 Co 4 and cubic crystalline AlCo phases is reported. The sample preparation is crucial to having Pb droplets lying on a clean surface. Decagonal and cubic films were prepared under high vacuum conditions, by sequential deposition and annealing of specific stackings of Al and Co layers of nanometre thicknesses. A 300?nm thick Pb slab was then deposited on the top of the films. Dewetting experiments were performed in situ in a scanning Auger microprobe where the surface chemistry can be monitored: the Pb slab dewets into droplets. The wetting of Pb on both substrates was found to be similar with contact angles around 45°. [ABSTRACT FROM AUTHOR]

This article attempts to understand better the origin of low friction and zero solid–solid adhesion observed on quasicrystals placed in vacuum. We present an ensemble of experimental data that allows us on the one hand to estimate the true surface energy of unoxidized quasicrystals and approximants and on the other hand to point out a correlation with electronic densities of states. [ABSTRACT FROM AUTHOR]

We used X-ray emission spectroscopy to investigate the electronic structure of various catalysts obtained by leaching a quasicrystalline Al–Cu–Fe compound in 5% Na 2 CO 3 aqueous solution. The study of Al states confirmed that Al is almost totally oxidized in the catalysts. Fe is not as much oxidized probably because it is embedded in Cu–Al 2 O 3 grains. Cu is only partly oxidized. However, it is not excluded that the catalytic activity could be due to a size effect that prevents the formation of a band as in metallic Cu, and gives to the electronic structure an atomic-like character. New measurements should be done from fresh specimens in order avoid further oxidation interference with the Cu spectral distributions. [ABSTRACT FROM AUTHOR]

Pseudo-binary IQC 100- x DQC x alloys made from mixing Al 62 Cu 25.5 Fe 12.5 icosahedral quasicrystal (IQC) and Al 70 Co 15 Ni 15 decagonal quasicrystal (DQC) together in progressively increased proportions were studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDAX). In this way the transition from IQC to DQC was manifested by the evolution of their constituent phases. The formation of these phases was found to follow the evolution of their valence electron concentration per atom ( e/a ) lines in the Al–(Cu,Ni)–(Fe,Co) pseudo-ternary phase diagram. An Al–Cu–Co type decagonal phase was found in the annealed IQC 80 DQC 20 alloy. This phase is characterized by transmission electron microscopy (TEM) and by high-resolution electron microscopy (HREM). The study proved that it is a superstructure of the DQC phase. The possible origin of its formation was discussed according to the variation of its DQC formation e/a -constant line in the Al–(Cu,Ni)–(Fe,Co) alloy system. [ABSTRACT FROM AUTHOR]

We have characterized by transmission electron microscopy several new phases that we have discovered in bulk alloys of the Al–Cr–Fe system. These structures are an icosahedral compound and several approximants of the decagonal phase. According to the indexation of the electron diffraction patterns (EDPs), some of the approximants are not of Fibonacci type. These EDPs correspond to nanodomains, which are due to disorder introduced by quenching the alloys after melting the pure constituent metals. For these new types of approximant, we propose a crystallographic description related to the usual Fibonacci description. In addition, we suggest a construction of the corresponding tilings. The orientation relationships between these structures are described. [ABSTRACT FROM AUTHOR]

We present new results concerning the formation of Al-based composites reinforced by icosahedral i -Al 59 Cu 25.5 Fe 12.5 B 3 quasicrystalline particles. The issue is to limit the diffusion of Al from the matrix to the quasicrystalline particles during sintering in order to overcome the transformation of the i -phase into the ?-Al 7 Cu 2 Fe tetragonal phase. Here we have investigated the influence of an oxidation pre-treatment of the quasicrystalline particles onto the kinetics of this phase transformation by high energy X-ray diffraction. The quasicrystalline particles were annealed either in vacuum or in air, leading to a different thickness of the oxide layer. We show that the oxide barrier efficiently reduces the kinetics of Al diffusion, enabling the formation of composite materials with no phase transformation during the sintering process. The dependence of the tribological properties of these composites is investigated as a function of the volume fraction of i -AlCuFeB particles. [ABSTRACT FROM AUTHOR]

We have identified two ?-brass phases in the Al–Cr–Fe system by X-ray diffraction and transmission electron microscopy. These structures (rhombohedral and cubic) are closely related to each other and can co-exist in the same alloy together with approximants of quasicrystals. In particular, a long-period superlattice, typical of ?-brass phases, was characterized in the cubic structure. This superstructure is constituted of inversion domains separated by boundaries lying at (10) planes. The displacement vector between like domains was determined from high resolution microscopy data. This study deals also with a description of some structural links between ?-brass phases and approximants of decagonal and icosahedral quasicrystals. [ABSTRACT FROM AUTHOR]

Microstructures and morphological features of a series of sintered quasicrystalline Al62.5-xCu25.3Fe12.2Bx alloys, with x ranging from 0 to 5 at.% were studied using x-ray diffraction, scanning electron microscopy, x-ray mapping, and electron probe microanalysis. Electron backscattering diffraction (EBSD) was also used to get information about the structures of some phases and identify the crystalline relationship in-between phases. Increasing x results in the change of the nature of extra phases. These secondary phases are all less than 1% in volume of the total matter except for the β phase at 5% of boron. Whatever the percentage of boron considered, boron seems to concentrate essentially in the parasite phases confirming doubts found in literature about the solubility of boron inside the face-centered-icosahedral Al-Cu-Fe phase. No special crystallographic relationship in between the tested phases could be spotted. EBSD is thus also confirmed as an excellent technique to get quasicrystalline grains orientations. [ABSTRACT FROM AUTHOR]

This paper reports the preparation conditions and structure characteristics of Al-Cr-Fe very thin films (10-30 nm) obtained by the flash evaporation technique. The films are either amorphous or crystallized, depending on the thickness of the sample and temperature of the substrate. Annealing of amorphous films leads to crystallization of intermetallic phases that are all linked with quasicrystals. In particular, we have identified by transmission electron microscopy the following structures: body-centered-cubic (bcc) γ-brass phase, monoclinic λ-Al13(Cr,Fe)4 phase, and orthorhombic O1-phase, all of them already observed in this system, together with four new structures, i.e., a face-centered-cubic (fcc) γ-brass phase (superstructure of the bcc phase), monoclinic λ′-phase (related to the λ-phase) and two orthorhombic phases (1/1/; 1/1) and (1/0; 2/1) approximants of the decagonal phase). In this study, we point out the occurrence of twin defects of the λ-Al13(Cr,Fe)4 phase. Films prepared directly in the crystalline state comprise the O1 approximant. Electron energy loss spectroscopy measurements show that all films are not oxidized except for the presence of a native oxide layer that forms in ambient atmosphere with a thickness that cannot exceed 0.3 nm. Optical properties were investigated and show that films need to be large enough (>30 nm) to reproduce the properties of bulk alloys. Finally, contact angle wetting measurements reveal that the presence of such films on a substrate, even at very low thickness, considerably decreases the wetting behavior by water. [ABSTRACT FROM AUTHOR]

Using the Soft X-ray Emission Spectroscopy technique, we have investigated the electronic structure of a series of Al-Cu-Fe compounds in which Al atoms have been substituted by Be atoms. Changes in the shape of Al 3s,d spectral curves are clearly visible in the energy region extending over 2 eV below the Fermi level. Calculation of the moments of orders 1 and 2 of the partial electronic distributions show that there is a slight decrease of the contribution of Fe 3d states to the total energy of the system and that there are changes in Fe hybridisation that tend to enhance the localised character of the Al states in the vicinity of the Fermi level. Yet, the shape of the pseudo-gap does not change. [ABSTRACT FROM AUTHOR]

Copyright of International Journal of Remote Sensing is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The coastal environment occupies a prime role in the economy and the development of Vietnam. To facilitate the planning of conservation and development measures in this sector, it is necessary to monitor on a continuous basis the changes occurring in the coastline. HRV SPOT-1 and SPOT-2 images, acquired respectively in 1986 and 1991, are used for determining the accumulation-erosion budget for a 14 km portion of coastline. Both aerial photographs acquired in 1986 and ground campaign results (1994) are used as ground data. After applying rigorous geometric corrections and sensor harmonization for stabilizing the dynamics of the HRV images in order to simulate the acquisition of the two images as if recorded by the same sensor, we are able to make a good image comparison. The SAVI vegetation index (Soil Adjusted Vegetation Index) is used as the basis for developing a binary mask solely for the vegetation cover on the remote sensing images. The removal of the 1991 mask from the 1986 mask enhances the predominance of erosion in the study area, i.e. 0.62 km over five years. However, because of the multidate character of remote sensing data it is possible to predict the overall trend in the evolution of the coastal environment. [ABSTRACT FROM AUTHOR]

We introduce a new method for the synthesis of Al-Ni nanosized particles. After partial oxidation, this technique is able to produce ultrafine sub-nanometric nickel clusters dispersed with an amorphous aluminium oxide. Such clusters consist of about 15 nickel atoms which exhibit discrete electronic energy levels and superparamagnetism. A very significant enhancement of the catalytic properties is observed. We expect that division of metals down to such a reduced scale will lead us to new properties and to a technological breakthrough since upscaling this method to industrial production rate is straightforward. [ABSTRACT FROM AUTHOR]

The Upper St. Lawrence estuary is an area where many physical factors such as the wind, the freshwater runoff, the tides and the bathymetry interact to generate a strong spatio-temporal variability of measurable parameters. Six Landsat-5 Thematic Mapper thermal images were analysed to study the sea surface temperature spatial variability of this complex region. Results show that the bathymetry is the principal factor controlling this structure. Sea surface temperatures are usually warmer in shallower areas. Bathymetry is also responsible for the localization of the principal density front close to le aux Coudres. Finally, the results show that the sea surface temperature is influenced by the intense tidal mixing and by wind-induced upwellings. Data analysis finally showed that the Thematic Mapper sensor was able to significantly detect spatial temperature gradients that are stronger than 1°C. L'estuaire superieur du Saint-Laurent est une region ou interagissent divers facteurs physiques tels que le vent, le debit d'eau douce, la maree et la bathymetrie qui generent une forte variabilite spatio-temporelle des parametres mesurables. Six images thermiques du capteur Thematic Mapper de Landsat-5 ont ete analysees afin d'etudier la structure spatiale du champ de temperature de surface de cette region complexe. Les resultats montrent que la bathymetrie est le facteur principal controlant cette structure. Les temperatures de surface de l'eau sont ainsi generalement plus chaudes dans les zones moins profondes. La bathymetrie est aussi responsable de la position du principal front de densite situe pres de l' le aux Coudres. Finalement, les resultats montrent que la temperature de surface de l'eau est aussi affectee par endroits par le melange intense cause par la maree ainsi que par des remontees d'eau induites par le vent. L'analyse des donnees a finalement permis de montrer que le capteur TM permettait de detecter de facon significative des changements spatiaux de temperature de surface de la mer lorsque ceux-ci sont superieurs a environ 1°C. [ABSTRACT FROM AUTHOR]

Underwater kelp seasonal variation is assessed through the comparative analysis of HRV and Thematic Mapper (TM) images of Baie des Chaleurs between Caps-Noirs and Pointe-Bonaventure, Quebec. The total biomass is estimated, based on the morphology of the dominant species Laminaria longicruris. Kelp-covered and kelp-free areas are differentiated from each other in water depth of 0-6 m and 0-7 m with the HRV and TM images, respectively. The median biomass estimated for the kelp-covered category of the classified image is (1500_400)g m[sup -2]. The multidate image shows a spatial variation of the kelp beds in 45% of the area. Areas where no change occurred occupy at least 70 ha, while growth and decay of kelp are observed in much smaller areas, in shallow water and at the boundary of kelp beds. [ABSTRACT FROM AUTHOR]

Un algorithme de simulation du signal d'une masse d'eau côtière au niveau d'un capteur satellitaire est présenté dans cet article. Il fait appel au code atmosphérique 6S pour le calcul du rayonnement solaire reçu par un capteur après réflexion par une masse d'eau, selon des conditions variables de l'atmosphère ainsi que de la géométrie d'illumination et de visée. Le calcul de la réflectance d'éclairement sous la surface de la masse d'eau se fait par un module spécialement conçu par nous. Ce module fait appel à des modèles approximatifs du transfert radiatif dans une masse d'eau d'une profondeur variable et limitée par un fond d'une nature et d'une couverture variable (ex. algues, sable, gravier). La masse d'eau peut être composée de plusieurs couches, chacune étant caractérisée par son contenu distinct en matières minérales en suspension, en matières organiques dissoutes et en chlorophylle. L'accent dans cette étude a étémis sur les données du capteur TM de Landsat, le seul à l'heure actuelle offrant un certain potentiel du point de vue résolution spectrale, spatiale et radiométrique pour l'étude du contenu des masses d'eau côtières. Dans un premier temps, les résultats du module de calcul de la réflectance d'éclairement ont été vérifiés pour les longueurs d'onde centrales des bandes TM1, TM2 et TM3, à l'aide de données acquises sous la surface de l'eau et publiées dans la littérature (masses d'eaux du type CASE I ou CASE II). Dans un deuxième temps, les résultats de l'ensemble de l'algorithme ont été vérifiés à partir d'une image TM et de données d'échantillonnage des eaux côtières de la baie des Chaleurs, au Québec, acquises en quasi-synchronisme avec le passage du satellite. Dans les deux cas l'algorithme proposémontre un bon comportement. En effet, les réflectances d'éclairement simulées sous la surface d'eau montrent un haut degré de similitude avec celles publiées. Quant aux résultats globaux, l'algorithme surestime de 2.5 niveaux de gris (échelle en 8 bits), en moyenne, le signal du système atmosphère-masse d'eau dans les trois bandes TM. Les causes probables de cette surestimation et les possibilités d'améliorer le rendement de l'algorithme sont discutées dans cet article. Un exemple de simulation du signal d'une masse d'eau côtière est également présenté pour démontrer le potentiel d'utilisation de l'algorithme. An algorithm was developed to simulate the radiometric and spectral behaviour of coastal waters at the satellite level. The algorithm uses the 6S atmospheric code to estimate the apparent radiance and apparent reflectance of the water surface under particular geometric (illumination, observation) and atmospheric conditions. The irradiance reflectance of the coastal waters was estimated by a specific module (SIREAUCO), integrated to 6S afterward. This module uses radiative transfer approximations and takes account for finite depth with bottom of different nature (e.g. algae, sand, gravel). The water volume itself may have multiple layers, each layer characterized by its content in chlorophyll, suspended minerals and dissolved organic matter. This study is oriented toward the use of the Landsat TM sensor because of its potential to give informative data over the coastal environment. First, data from SIREAUCO alone were compared to reflectance values taken from published spectral signatures at the central wavelength of the first three TM bands. Then, output data from the complete algorithm were validated with a TM image and in situ sampling data from the coastal waters of Baie des Chaleurs, Québec. The sampling was almost synchronized with the image acquisition. In both validation cases, results from the algorithm showed good agreement. In fact, irradiance reflectance from SIREAUCO showed a high degree of conformity with the published data. On a more global scale, the algorithm overestimate the signal calculated for the complete atmosphere-water system, in each TM band, by an average of 2.5 digital number (8 bits scale). Causes of the overestimation and possibilities to increase confidence in the algorithm are discussed. The potential of this algorithm is also presented through a concrete example of a simulation in coastal waters. [ABSTRACT FROM AUTHOR]

K+ and Cl– channels are involved in regulating the proliferation of a number of cell types. Two main hypotheses have been proposed to explain the mechanism by which these channels influence cell proliferation: regulation of membrane potential and regulation of cell volume. In order to test these hypotheses, we measured, under different experimental conditions, the volume, membrane potential and rate of proliferation of C6 glioma cells. Cells cultured in control medium for 1–4 days were compared with cells cultured for the same period of time in the presence of broad spectrum channel blockers: tetraethylammonium, 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) and Cs+, in hypertonic media (29% increased osmolarity with NaCl, KCl or sucrose), in hypotonic medium (23% decreased osmolarity with H2O) or in the presence of the specific channel blockers, i.e. mast cell degranulating peptide, charybdotoxin or chlorotoxin. In all of these conditions, we observed a close correspondence between the rate of proliferation and the mean cell volume. The proliferation decreased when volume increased. Moreover, whereas control cells were flattened, spindle-shaped, bipolar or multipolar, cells cultured in media supplemented with NPPB, KCl or CsCl were round with few processes. Of the agents tested, only KCl and Cs+ depolarized the cells. These results show that alterations of the rate of proliferation by K+ and Cl– channel blockers or anisotonia are closely related with changes in cell volume or form but are not correlated with changes in membrane potential. [ABSTRACT FROM AUTHOR]

Microstructure modifications induced by sliding a WC-Co indenter in scratch tests on the surface of a single-phase Al-Cu-Fe icosahedral quasicrystal (IQC) was studied by scanning electron microscopy and transmission electron microscopy. The scratch track was shown to consist of many smaller tracks. Dislocations were discovered to emerge from the edges of the smaller scratch tracks. Along a small track where the shear stress is concentrated, a phase transition from an IQC to a bcc phase with lattice parameter a = 0.29 nm was found to occur. A modulated quasicrystal state as well as a deformation twin of IQC were determined in the region beneath the scratch. [ABSTRACT FROM AUTHOR]

Finely dispersed Ni powders were obtained after chemical reduction of Ni(II) salts by activated sodium hydride in organic solvents. This process allows one to prepare particles in the nanometre range. The particles with sizes smaller than 4 nm were found to be hcp whereas larger particles were fcc. To the best of our knowledge, this is the first observation that unsupported Ni powder may crystallize in the hcp system and that the phase stability of this metallic element is particle size dependent. [ABSTRACT FROM AUTHOR]

The aim of this note is to test an empirical algorithm using spectral curvature theory at selected SeaWiFS hyerspectral bands, in order to estimate the chlorophyll pigment concentrations in the coastal waters of Baie des Chaleurs (Gulf of St. Lawrence). Simulated SeaWiFS algorithms require the measurement of reflectances with a high sensitive spectroradiometer as well as the responsitivity of SeaWiFS sensor at each band. Volume reflectances were taken using a hand held spectroradiometer simultaneously to measurements of in situ chlorophyll pigment concentrations. An empirical algorithm of the form: log (chlorophyll pigments) 0.92-0.46 Delta2 log R0sea(555) yields an estimate of chlorophyll pigment concentrations within a mean deltaC / C of 23%. [ABSTRACT FROM AUTHOR]