1,318 research outputs found
Postnatal growth and development pattern of camel calves
Trente-deux chameaux de Bactriane élevés dans des conditions traditionnelles d'élevage ont été suivis pour étudier leur croissance post-natale et leur profil de développement. Treize mesures corporelles linéaires ont été faites à trente jours d'intervalle depuis la naissance jusqu'au 420 ème jour. Les taux moyens de croissance pour la hauteur, le tour de poitrine, la longueur, la circonférence de l'os canon, la profondeur et la largeur du poitrail, la longueur et la largeur de la croupe, la longueur des pattes, la longueur et la largeur de la tête et la longueur du cou ont été évalués. Les résultats ont montré que, dans une large mesure, les différentes dimensions corporelles avaient un profil de maturité uniforme et que leur hiérarchie tendait à rester constante pendant toute la période d'observation. Les taux de croissance rapide correspondaient à un allaitement maternel satisfaisant. Le profil de croissance du poids vif suivait la courbe de la plupart des mammifères. Cependant la croissance a été plus rapide au cours des sept premiers mois et le gain de poids moyen quotidien (gmq) le plus important a été constaté au cours du 3e mois, avec une moyenne de 0,782 ± 0,349 kg. Un gmq négatif a été observé entre le 1Oe et le 11e mois avec une moyenne de -0,1677 ± 0,19 kg pour les mâles et de -0,006 ± 0,24 kg pour les femelles, lorsque la mère entrait en période de reproduction et que la production laitière chutait. Le gmq moyen sur 420 jours a été de 0,3846 ± 0,2895 kgd-1. Les courbes de croissance standardisées ont permit de déduire le degré de maturité en termes de poids vif et d'âge. (Résumé d'auteur
On the Benign One-Pot Preparation of Nanoporous Copper Thin Films with Bimodal Chan-nel Size Distributions by Chemical Dealloying in an Alkaline Solution
Nanoporous copper (NPC) thin films with bimodal channel size distributions can be benignly fabricated by one-pot chemical dealloying of dual-phase Al 27 at Cu alloy with hypereutectic structure in the NaOH solution. The microstructure of these NPC thin films was characterized using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis. The results show that these NPC thin films are composed of interconnected large-sized channels (100s of nm) with highly porous channel walls (10s of nm), in which large-sized channels resulting from entire dissolution of solid solution while small-sized those de-riving from part corrosion of intermetallics. Both large- and small-sized channels are 3D, open, and bicon-tinuous.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3520
Preparation of Nanostructured Li2MnO3 Cathode Materials by Single-Step Hydrothermal Method
Nanosized (10~50 nm) cathode material Li2MnO3 was prepared for with MnSO4·H2O,KMnO4 and Li-
OH aqueous solution as the precursor via single-step hydrothermal reaction by controlling the reaction
time, proportion of processor, and the reagent concentration. The prepared materials were well crystallized
and exhibited a monoclinic Li2MnO3 structure with a space group of C2/m phase. The electrochemical performance
of the material was tested at current density of 60 mAg-1 (1/4 C) between 4.3V and 2.0 V at room
temperature, showing good electrochemical properties with the initial discharge capacity of 243 mAh·g-1,
because it was more exposed to the electrolyte due to its nanostructure.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3519
Structure and Electrochemical Performance of Li[Li0.2Co0.4Mn0.4]O2 Cathode Material for Lithium Ion Battery by Co-precipitation Method
The nano-structured Li[Li0.2Co0.4Mn0.4]O2 cathode material is synthesized by a co-precipitation method. X-ray diffraction shows that the synthesized material has a hexagonal α-NaFeO2 type structure with a space group R-3m. Scanning electron microscopy and transmission electron microscopy images show the homogeneous distribution with 100-200 nm. X-ray photoelectron spectroscopy results indicate that the oxi-dation states of Co and Mn in Li[Li0.2Co0.4Mn0.4]O2 are present in trivalence and tetravalence, respectively. The charge-discharge curves and cycling performance are analyzed in detail. The initial charge and dis-charge capacities are respectively 236.5 mAh g-1 and 140.3 mAh g-1 at the current density of 100 mA g-1 in the voltage range of 2.0-4.6 V.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3520
Multi-neutron transfer coupling in sub-barrier 32S+90,96Zr fusion reactions
The role of neutron transfers is investigated in the fusion process below the
Coulomb barrier by analyzing 32S+90Zr and 32S+96Zr as benchmark reactions. A
full coupled-channel calculation of the fusion excitation functions has been
performed for both systems by using multi-neutron transfer coupling for the
more neutron-rich reaction. The enhancement of fusion cross sections for
32S+96Zr is well reproduced at sub-barrier energies by NTFus code calculations
including the coupling of the neutron-transfer channels following the Zagrebaev
semiclassical model. We found similar effects for 40Ca+90Zr and 40Ca+96Zr
fusion excitation functions.Comment: Minor corrections, 11 pages, 4 figures, Fusion11 Conference, Saint
Malo, France, 2-6 mai 201
Properties and Performance of Two Wide Field of View Cherenkov/Fluorescence Telescope Array Prototypes
A wide field of view Cherenkov/fluorescence telescope array is one of the
main components of the Large High Altitude Air Shower Observatory project. To
serve as Cherenkov and fluorescence detectors, a flexible and mobile design is
adopted for easy reconfiguring of the telescope array. Two prototype telescopes
have been constructed and successfully run at the site of the ARGO-YBJ
experiment in Tibet. The features and performance of the telescopes are
presented
A self-consistent method to analyze the effects of the positive Q-value neutron transfers on fusion
AbstractConsidering the present limitation of the need for external parameters to describe the nucleus–nucleus potential and the couplings in the coupled-channels calculations, this work introduces an improved method without adjustable parameter to overcome the limitation and then sort out the positive Q-value neutron transfers (PQNT) effects based on the CCFULL calculations. The corresponding analysis for Ca+Ca, S,Ca+Sn, and S,Ca+Zr provides a reliable proof and a quantitative evaluation for the residual enhancement (RE) related to PQNT. In addition, the RE for S32,Ca40+Zr94 shows an unexpected larger enhancement than S32,Ca40+Zr96 despite the similar multi-neutron transfer Q-values. This method should rather strictly test the fusion models and be helpful for excavating the underlying physics
Charge ordering in charge-compensated by oxonium ions
Charge ordering behavior is observed in the crystal prepared through the
immersion of the crystal in distilled water. Discovery of the
charge ordering in the crystal with Na content less than 0.5 indicates that the
immersion in water brings about the reduction of the
. The formal valence of Co changes from +3.59 estimated from
the
Na content to +3.5, the same as that in . The charge
compensation is confirmed to arise from the intercalation of the oxonium ions
as occurred in the superconducting sodium cobalt oxide
bilayer-hydrate.\cite{takada1}
The charge ordering is the same as that observed in . It
suggests that the Co valence of +3.5 is necessary for the charge ordering.Comment: 5 pages, 4 figure
Enhancement of the magnetic anisotropy of nanometer-sized Co clusters: influence of the surface and of the inter-particle interactions
We study the magnetic properties of spherical Co clusters with diameters
between 0.8 nm and 5.4 nm (25 to 7500$ atoms) prepared by sequential sputtering
of Co and Al2O3. The particle size distribution has been determined from the
equilibrium susceptibility and magnetization data and it is compared to
previous structural characterizations. The distribution of activation energies
was independently obtained from a scaling plot of the ac susceptibility.
Combining these two distributions we have accurately determined the effective
anisotropy constant Keff. We find that Keff is enhanced with respect to the
bulk value and that it is dominated by a strong anisotropy induced at the
surface of the clusters. Interactions between the magnetic moments of adjacent
layers are shown to increase the effective activation energy barrier for the
reversal of the magnetic moments. Finally, this reversal is shown to proceed
classically down to the lowest temperature investigated (1.8 K).Comment: 13 figures submitted to Phys. Rev.
Surface structure and solidification morphology of aluminum nanoclusters
Classical molecular dynamics simulation with embedded atom method potential
had been performed to investigate the surface structure and solidification
morphology of aluminum nanoclusters Aln (n = 256, 604, 1220 and 2048). It is
found that Al cluster surfaces are comprised of (111) and (001) crystal planes.
(110) crystal plane is not found on Al cluster surfaces in our simulation. On
the surfaces of smaller Al clusters (n = 256 and 604), (111) crystal planes are
dominant. On larger Al clusters (n = 1220 and 2048), (111) planes are still
dominant but (001) planes can not be neglected. Atomic density on cluster
(111)/(001) surface is smaller/larger than the corresponding value on bulk
surface. Computational analysis on total surface area and surface energies
indicates that the total surface energy of an ideal Al nanocluster has the
minimum value when (001) planes occupy 25% of the total surface area. We
predict that a melted Al cluster will be a truncated octahedron after
equilibrium solidification.Comment: 22 pages, 6 figures, 34 reference
- …
