Quantitative analysis of mixed (Mo,W) carbides by means of least-squares minimization performed on auger spectra simulations

Abstract

The effective stiffness of materials that are impregnated with magnetic nanoparticles can be modulated by magnetic fields if the nanoparticle Néel relaxation rates are slower than the characteristic deformation rates. A numerical analysis indicates that the deflection of magnetic dipoles against the applied magnetic field on deformation of the material provides the energy absorption necessary for the enhanced stiffness observed in drop ball impact tests. The penetration depth, fraction of the impact energy that is absorbed by the rotating dipoles, and the effective increase in stiffness are shown to depend uniquely on the ratio of the characteristic magnetic energy density relative to the elastic energy density, and on the shape of the impacting object.

Field emission from Mo2C coated carbon nanosheets

“…16 The inset of Fig. [20][21][22] This overlayer AES structure has been observed at temperatures as low as the deposition temperature of ϳ75°C. Density functional studies on the array of bonding sites on a perfect graphene surface and on an array of sites on the edges suggest that these adsorption energies can run from 0.5 to 3 eV.…”

“…Density functional studies on the array of bonding sites on a perfect graphene surface and on an array of sites on the edges suggest that these adsorption energies can run from 0.5 to 3 eV. [20][21][22] The amount of carbide was determined by the method of Baldwin et al, utilizing the asymmetry ratio, AR= i + / i − , where i + and i − are the positive and negative portions of the major peak in the carbide AES signal. 14 The AES spectra of the as-grown CNS after bakeout ͑275°C for 2 h͒ is shown in Fig.…”

Preparation and Characterization of Tungsten Carbides as Alkaline Fuel Cell Catalysts

“…The resulting materials have a low specific surface area and low purity, and these commercial materials are unsuitable as catalysts. The methods have been used including methane carburization of oxides [9,[14][15][16][17][18][19]27,28], methane carburization of nitrides [24,27], ethane carburization of oxides [27], propane carburization of sulfide [26] and carburization of tungsten [29]. Besides these common ways, tungsten carbides were also synthesized by carbothermal hydrogen reduction and metal-promoted carbothermal hydrogen reduction on ultrahigh-surface-area carbon material [2], reduction of scheelite CaWO 4 to tungsten carbide [30], low pressure chemical vapour deposition of tungsten carbide [31], flame initiated or bulk thermal reactions of mixed powders of transition metal halides and CaC 2 or Al 4 C 3 [32], bulk reactions of transition metal oxides with calcium and strontium carbides [33], combustion synthesis of tungsten carbides under electric field [1], sonochemical preparation with W(CO) 6 as the starting material [25], chemical vapour deposition (CVD) and physical vapour deposition (PVD) processes [ 3 4 ] , f i e l d -a c t i v a t e d c o m b u s t i o n s y n t h e s i s ( F A C S ) o f equal atomic mixtures of tungsten and activated carbon.…”