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•(Co1−xMnx)3O4 solid solution is synthesized in water at 60°C by soda addition.•The particles are well crystallized and exhibit a size close to 50nm.•Each particle is composed by ...several crystallographic domains of about 10nm.•Precipitation is a simple, fast and safe process.
The (Co1−xMnx)3O4 solid solution have been synthesized in water at 60°C by soda addition to a cationic solution. XRD patterns show that spinel oxide has been obtained except for pure cobalt composition which exhibits also the presence of hydroxide and oxy-hydroxide. Therefore, to reach this composition, a different synthesis route has been developed: the cationic solution is added to the soda and for the first time Co3O4 nanoparticles have been synthesized by a direct precipitation in aqueous solution at low temperature. For each composition, the particles are well crystallized and exhibit a size close to 50nm. Each particle is composed by several crystallographic domains of about 10nm. The cubic to tetragonal transition reported in the literature for x=0.46 is observed in between x=0.33 and x=0.50. Raman spectra show that substitution of Co by Mn, in the cubic phase, introduces a random high disorder. In the tetragonal phase, occupation of the octahedral site remains a random occupation, while the tetrahedral site seems to be preferentially occupied by Co ions. All these results show that the precipitation is a simple, fast and safe process to synthesize pure phase of (Co1−xMnx)3O4 spinel solid solution in aqueous media at low temperature.
Deficient voluntary control of behaviour and impulsivity are key aspects of impulse control disorders. The objective of the present study was to evaluate the relationship between behavioural measures ...of impulsivity and the awareness of voluntary action. Seventy‐four healthy volunteers completed the Barratt Impulsiveness Scale (BIS), a questionnaire used to measure impulsive personality traits, and a go/no‐go task. Moreover, all participants performed a behavioural task based on the Libet's clock paradigm in which they were requested to report the time of a self‐initiated movement (M‐judgement) or the time they first feel their intention to move (W‐judgement). A positive relationship between the time in which subjects reported the intention to move (W‐judgement) and impulsivity measures emerged. Namely, the higher was the score in the attentional and motor impulsivity subscales of the BIS and the number of inhibitory failure responses in the go/no‐go task, the lower was the difference between the W‐judgement and the actual movement (i.e. the awareness of intention to move was closer to the voluntary movement execution). In contrast, no relationship emerged with M‐judgement. The present findings suggest that impulsivity is related to a delayed awareness of voluntary action. We hypothesize that in impulse control disorders, the short interval between conscious intention and actual movement may interfere with processes underlying the conscious ‘veto’ of the impending action.
Our goal was to test the hypothesis that impulsivity could be related to a delayed awareness of voluntary action. Our main finding was that in healthy participants the time between the conscious intention to move and the execution of a self‐initiated movement is related to impulsive personality traits. These data may have potential clinical implications, e.g. in Parkinson's disease, in order to identify patients at risk to develop impulse control disorders.
Abstract
A new detailed infrared (IR) study of eight star-forming dense condensations (TCs) in M 20, the Trifid nebula, is presented. The aim is to determine the physical properties of the dust in ...such globules and establish the presence and properties of their embedded protostellar and/or young stellar population. For this, we analysed new Herschel far-IR and Calar Alto near-IR images of the region, combined with Spitzer Infrared Array Camera (Spitzer/IRAC) archival observations. We confirm the presence of several young stellar objects (YSOs), most with mid-IR colours of Class II sources in all but one of the observed cores. Five TCs are dominated in the far-IR by Class I sources with bolometric luminosities between 100 and 500 L⊙. We report the discovery of a possible counterjet to HH 399 and its protostellar engine inside the photodissociation region TC2, as well as a bipolar outflow system, signposted by symmetric H2 emission knots, embedded in TC3. The present results are compatible with previous suggestions that star formation has been active in the region for some 3 × 105 yr, and that the most recent events in some of these TCs may have been triggered by the expansion of the H ii region. We also obtained a revised value for the distance to M 20 of 2.0 ± 0.1 kpc.
In this study, a new route is described in order to obtain wires which can reach a few hundreds of micrometers long. ZnO rod is sintered at 900°C for 10h in air. Then the centimetric rod is placed in ...an optical furnace. The optical furnace allows to reach a thermal gradient of about 350°C/cm. In a first step, the vaporization of ZnO occurs, and in a second step the condensation of ZnO on the rod appears and leads to the growth of ZnO microwires (MWs). In few minutes, the MWs can reach in the c-direction a dimension higher than 100μm with a diameter close to ten microns. The shape of the MWs is hexagonal which is consistent with the crystal structure of ZnO (P63mc group). The MWs exhibit a high crystalinity.
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•The optical furnace allows to obtain ZnO micro-wires of few hundred micrometers long with a section of about 10μm.•The Mws exhibit an high crystalinity.•A lamp power increase allows to obtain ZnO tetrapods.
A high temperature thermal treatment after precipitation from an aqueous solution is usually required to reach crystalline SnO2 nanoparticles but this treatment generates a grain growth (up to 40nm). ...Moreover, the yield is generally low (<80%). In this paper, a new high yield one-pot aqueous synthesis of crystalline SnO2 nanoparticles is described. The synthesis is performed at 100°C under reflux: it exhibits a reaction yield over 90% and the particles are crystallized with a size of 4–6nm.
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•A synthesis route for crystalline SnO2 nanoparticles in water is presented.•The average particle size is 4–6nm.•The new synthesis route exhibits a reaction yield over 90%.
Pure ZnO and single Al-doped ZnO compounds without secondary phase have been obtained by SPS process. Starting powders prepared by co-precipitation have been synthesized. The sintered pellets exhibit ...different texture degree but similar isotropic shaped grains. Sintering mechanisms are proposed for both powders, explaining the different texture and grain size evolutions as a direct consequence of the differences observed in both compounds. The influence of texture and grain morphology on the thermoelectric properties is studied.
A new development of the TomoRebuild software package is presented, including “thick sample” correction for non linear X-ray production (NLXP) and X-ray absorption (XA). As in the previous versions, ...C++ programming with standard libraries was used for easier portability. Data reduction requires different steps which may be run either from a command line instruction or via a user friendly interface, developed as a portable Java plugin in ImageJ. All experimental and reconstruction parameters can be easily modified, either directly in the ASCII parameter files or via the ImageJ interface. A detailed user guide in English is provided. Sinograms and final reconstructed images are generated in usual binary formats that can be read by most public domain graphic softwares. New MLEM and OSEM methods are proposed, using optimized methods from the NiftyRec medical imaging library. An overview of the different medical imaging methods that have been used for ion beam microtomography applications is presented. In TomoRebuild, PIXET data reduction is performed for each chemical element independently and separately from STIMT, except for two steps where the fusion of STIMT and PIXET data is required: the calculation of the correction matrix and the normalization of PIXET data to obtain mass fraction distributions. Correction matrices for NLXP and XA are calculated using procedures extracted from the DISRA code, taking into account a large X-ray detection solid angle. For this, the 3D STIMT mass density distribution is used, considering a homogeneous global composition. A first example of PIXET experiment using two detectors is presented. Reconstruction results are compared and found in good agreement between different codes: FBP, NiftyRec MLEM and OSEM of the TomoRebuild software package, the original DISRA, its accelerated version provided in JPIXET and the accelerated MLEM version of JPIXET, with or without correction.
The optical behavior of the Be star in the high-mass X-ray transient A0535+26/HDE245770 shows that at periastron the luminosity is typically enhanced by 0.02 to a few tenths mag, and the X-ray ...outburst occurs eight days after the periastron. We constructed a quantitative model for this event based on a nonstationary accretion disk behavior, connected with a high ellipticity of the orbital motion. We explain the observed time delay between the peaks of the optical and X-ray outbursts in this system by the time of radial motion of the matter in the accretion disk, after an increase of the mass flux in the vicinity of a periastral point in the binary. This time is determined by the turbulent viscosity with a parameter of α = 0.1−0.3. The increase of the mass flux is a sort of flush that reaches the external part of the accretion disk around the neutron star, which enhances the optical luminosity. The subsequent X-ray flare occurs when the matter reaches the hot central parts of the accretion disk and the neutron star’s surface.
Synchronization of body movements to an external beat is a universal human ability, which has also been recently documented in nonhuman species. The neural substrates of this rhythmic motor ...entrainment are still under investigation. Correlational neuroimaging data suggest an involvement of the dorsal premotor cortex (dPMC) and the supplementary motor area (SMA). In 14 healthy volunteers, we more specifically investigated the neural network underlying this phenomenon using a causal approach by an established 1-Hz repetitive transcranial magnetic stimulation (rTMS) protocol, which produces a focal suppression of cortical excitability outlasting the stimulation period. Synchronization accuracy between rhythmic cues and right index finger tapping, as measured by the mean time lag (asynchrony) between motor and auditory events, was significantly affected when the right dPMC function was transiently perturbed by "off-line" focal rTMS, whereas the reproduction of the rhythmic sequence per se (inter-tap-interval) was spared. This approach affected metrical rhythms of different complexity, but not non-metrical or isochronous sequences. Conversely, no change in auditory-motor synchronization was observed with rTMS of the SMA, of the left dPMC or over a control site (midline occipital area). Our data strongly support the view that the right dPMC is crucial for rhythmic auditory-motor synchronization in humans.
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