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11.
J.V. Lobato N. Sooraj Hussain C.M. Botelho A.C. Maurício A. Afonso J.D. Santos 《Thin solid films》2006,515(1):362-367
Synthetic bone grafts have been developed to provide an alternative to autografts and allografts. Bonelike® is a patented synthetic osteoconductive bone graft that mimics the mineral composition of natural bone. In the present preliminary animal studies a user-friendly version of synthetic bone graft Bonelike® have been developed by using a resorbable matrix, Floseal®, as a vehicle and raloxifene hydrochloride as a therapeutic molecule, that is known to decrease osteoclast activity and therefore enhanced bone formation. From histological and scanning electron microscopy evaluations, the use of Bonelike® associated with Floseal® and raloxifene hydrochloride showed that new bone was rapidly apposed on implanted granules and also that the presence of the matrix and therapeutic molecule does not alter the proven highly osteoconductivity properties of Bonelike®. Therefore, this association may be one step-forward for the clinical applications of Bonelike® scaffolds since it is much more easy-to-handle when compared to granular materials. 相似文献
12.
Summary Polymer composites have recently received a considerable amount of scientific and technological interest, because their properties
can be properly controlled, choosing the adequate doped particles, their size and concentrations, and the synthesis conditions.
In this work we report the synthesis and characterization of a polystyrene (PS) matrix doped with different concentrations
of iron nanoparticles.
X-ray diffraction and transmission electron microscopy were used to characterize the structure of the samples. The behaviour
of the d.c. electrical conductivity (σdc) and the complex permittivity (ε*=ε′-iε′′) as a function of frequency (100 Hz–10 MHz) reflects the important effect of the iron nanoparticles concentration in the
sample properties. A percolation threshold in the conductivity was observed at a critical concentration of iron nanoparticles.
A noticeable increase in the saturation magnetization and coercivity is observed with the rise of the iron nanoparticles concentration,
being thisbehaviour also noticed in the remanent magnetization. A rise of the initial a.c. susceptibility with the iron concentration
is also observed. 相似文献
13.
Schottky diodes were built on different polycrystalline diamond films grown by Microwave Plasma and Hot Filament Chemical Vapor Deposition and their electrical properties were studied. The barrier height increased with the diamond film quality and the corresponding ideality factor decreased. Even though the lower-quality HFCVD film displayed poor rectifying properties, it was found to be much less sensitive to variations in the operating conditions (air vs. vacuum). The activation energies of the films depend on morphological parameters, as preferable grain size or orientation. The bulk conduction also depends on the quality of the deposited films, changing from ohmic to trap-free or shallow trap SCLC and SCLC with an exponential distribution of traps. The hypothesis of using the electrical measurements as an indicator for film quality has been discussed. 相似文献
14.
15.
《Environmental Modelling & Software》2007,22(10):1488-1497
A Laplace transform representation is used to describe the changes in atmospheric CO2 in response to emissions. The formalism gives an explicit representation of generic relations that are less clear when model results are presented as numerical integrations with particular parameter values. In particular, the Laplace transform formalism clarifies some issues involved in inversion of ice-core data and analysis of geosequestration. The airborne fraction is expressed as the emission growth rate multiplied by the Laplace transform of the atmospheric response function, evaluated at the growth rate. This representation emphasises that historical data only capture carbon cycle dynamics over a limited range of time-scales. The Laplace transform formalism provides a basis for expressing uncertainties in the response function in terms of the Padé–Laplace transformation used for fitting sums of exponentials. 相似文献
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17.
Weldable primers are thin zinc-rich organic coatings that are weldable due to the electrical conductivity provided by the zinc dust. They are used in the automotive industry to provide corrosion protection in regions of difficult access. The zinc particles are highly susceptible to corrosion attack and, due to the small thickness, the protection conferred by these systems is limited. 相似文献
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19.
1,12-bis(1,2,4-triazolyl)dodecane (dTC12) is an excellent corrosion inhibitor for carbon steel in deaerated 1 M HCl solution. In this work electrochemical and analytical techniques were used to study the inhibition of corrosion on carbon steel in acidic medium. The carbon steel corrosion inhibition of dTC12 was attributed to the synergistic effect between chloride anion and quaternary ammonium ion. The protective efficiency of the film was higher than 90%, indicating that corrosion of carbon steel in 1 M HCl is reduced by dTC12.The effect of dissolved oxygen on the inhibition efficiency was also investigated. The results show that the inhibition efficiency increases in early stage and decreases for a long immersion time. 相似文献
20.
V.V. Kharton A.L. Shaula F.M.M. Snijkers J.F.C. Cooymans J.J. Luyten I.P. Marozau A.P. Viskup F.M.B. Marques J.R. Frade 《Journal of the European Ceramic Society》2006,26(16):3695-3704
Moderate additions of Al2O3 to strontium ferrite-based mixed conductors, such as SrFe0.7Al0.3O3−δ and La0.2Sr0.8Fe0.8Ga0.2O3−δ with the composition close to the solid solution formation limits, make it possible to improve ceramics sinterability, to increase oxygen permeability and to decrease thermal expansion. These effects are associated with the segregation of alumina-rich phases, primarily SrAl2O4, and the formation of A-site cation-deficient perovskite. The improved properties of the SrFe0.7Al0.3O3-based material were used to fabricate high-quality tubular membranes for methane conversion reactors. Similar enhancement in sinterability is also observed for another promising parent material of mixed-conducting membranes, La0.5Sr0.5FeO3−δ. However, extensive dissolution of Al3+ cations in the iron sublattice, creation of A-site vacancies and changing the La:Sr concentration ratio all lead to decreasing ionic transport in La0.5Sr0.5FeO3−δ. As a result, additions of either Al2O3 or SrAl2O4 have a deteriorating influence on the oxygen permeation fluxes through La0.5Sr0.5FeO3-based ceramics. 相似文献