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101.
ELECTROLESS METALLIZATION of insulatingmaterials is currently used in industry since severaldecades.In its most common applications it consists ina redox reaction between Ni(+2)or Cu(+2)ions and astrong reducer(respectively hypophosphite,H2PO2,forNi(+2)and formaldehyde,HCHO,for Cu(+2))bothcontained in the same solution.The reaction initiationis generally catalyzed by palladium,then the redoxreaction goes on thanks to the remarkable property ofNi and Cu in their metallic state to … 相似文献
102.
The computational modeling programs described in part II of this series are used in two ways. One is to compare program predictions
to previous experimental data, thereby testing to some extent the utility of the programs. At this stage of their development,
program “predictions” with respect to processing time, microstructural scale, and similar parameters are accurate to within
a factor of 2 or so. Even so, the predictions offer support of the model developed in part I of this series and provide a
vehicle for both model and process refinements. In addition to “testing” the model and the program in these manners, the effect
of uncertainty in input material properties on program predictions is explored.
Formerly Graduate Student, Department of Materials Science and Engineering, University of Virginia, Charlottesville, VA 22903
Formerly Professor, Department of Materials Science and Engineering, University of Virginia 相似文献
103.
104.
C. Maurice D. Piot H. Klocker J. H. Driver 《Metallurgical and Materials Transactions A》2005,36(4):1039-1047
A thoroughly tested, high-temperature channel-die compression (CDC) rig is described for simulating hot plane strain compression
of metallic alloys up to 500 °C. The equipment is currently used to characterize the flow stress and microstructure evolution
in hot-rolled Al alloys. It has been validated by several tests involving (1) metallographic analysis of deformed samples;
(2) flow stress comparisons with the same, or similar alloys deformed in conventional uniaxial or plane strain compression;
and (3) microstructure and texture measurements. The use of modern lubricants enables one to obtain accurate flow stresses
and true plane strain deformations that are homogeneous over 80 pct of the sample. The equipment also features rapid heating
and cooling systems to minimize thermally-induced microstructure changes. Some results on high-temperature slip systems, hot
deformation textures, and microstructures, and the behavior of constituent particles are outlined to illustrate the advantages
of the technique. 相似文献
105.
Giuditta Franco Maurice Margenstern 《Electronic Notes in Theoretical Computer Science》2007,171(2):15
We propose a biologically inspired system which computes on double structures of mobile strings by means of rewriting rules that have a biotechnological implementation, by resembling DNA computations. Its computational universality may be straight deduced from a few formal language theoretical results of one of the authors. Such a DNA-like computational device is naturally described by a membrane system which concludes the paper. 相似文献
106.
107.
108.
Jolanta Światowska-Mrowiecka Vincent Maurice Sandrine Zanna Lorena Klein Emrick Briand Ian Vickridge Philippe Marcus 《Journal of power sources》2007
Cyclic voltammetry, XPS, RBS and AFM have been combined to study the ageing mechanism of Li intercalation in V2O5 thin films prepared by thermal oxidation of vanadium metal. Multi-cycling tests were performed in 1 M LiClO4-PC in the potential range E ∈ [3.8, 2.8 V] versus Li/Li+, corresponding to the α-to-δ phase transition. XPS and AFM were performed using direct anaerobic and anhydrous transfer. Capacity fading remains inferior to 20% during ∼2500 cycles. XPS shows slight modifications of the oxide composition with a V4+ concentration increasing from ∼5% prior to cycling to ∼16–27% after cycling, due to Li trapped in the oxide film and to the loss of V2O5 active material. The presence of lithium carbonate and lithium-alkyl carbonate species evidences the formation of the so-called SEI layer. AFM evidences the loss of crystalline material by grain exfoliation from the outer V2O5 layer of the oxide film. By further exfoliation, the inner VO2 layer of the oxide film is reached and pits are formed, occupying ∼9–13% of the surface. This de-cohesion at grain boundaries is attributed to the strain generated by repeated lattice distortions. After 3300 cycles, the disappearance of lithium carbonates, whereas Li-alkyl carbonates and/or Li-alkoxides remain on the surface, indicates the dissolution and/or conversion of the SEI layer. After 4500 cycles, the oxide film became very labile and could be stripped away by rinsing to reveal the vanadium metal substrate. 相似文献
109.
Fe(3)O(4) coated polypyrrole (PPy) magnetic nanocomposite was prepared via in situ polymerization of pyrrole monomer for the removal of highly toxic Cr(VI). Structure and morphology of the prepared nanocomposite were characterized by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), X-ray diffraction pattern, Field emission scanning electron microscopy (FE-SEM) and high resolution transmission electron microscopy (HR-TEM). Electron spin resonance (ESR) studies confirmed that the nanocomposite is magnetic in nature. Up to 100% adsorption was found with 200mg/L Cr(VI) aqueous solution at pH 2. Adsorption of Cr(VI) on the surface of the adsorbent was confirmed by the ATR-FTIR and X-ray photoelectron spectroscopy (XPS). XPS studies also suggested that ion exchange and reduction on the surface of the nanocomposite may be the possible mechanism for Cr(VI) removal by the PPy/Fe(3)O(4) nanocomposite. Adsorption results showed that Cr(VI) removal efficiency by the nanocomposite decreased with an increase in pH. Adsorption kinetics was best described by the pseudo-second-order rate model. Isotherm data fitted well to the Langmuir isotherm model. Thermodynamic study revealed that the adsorption process is endothermic and spontaneous in nature. Desorption experiment showed that in spite of the very poor recovery of the adsorbed Cr(VI); the regenerated adsorbent can be reused successfully for two successive adsorption-desorption cycles without appreciable loss of its original capacity. 相似文献
110.
Synthesis of few-layered graphene by ion implantation of carbon in nickel thin films 总被引:1,自引:0,他引:1
Baraton L He Z Lee CS Maurice JL Cojocaru CS Gourgues-Lorenzon AF Lee YH Pribat D 《Nanotechnology》2011,22(8):085601
The synthesis of few-layered graphene is performed by ion implantation of carbon species in thin nickel films, followed by high temperature annealing and quenching. Although ion implantation enables a precise control of the carbon content and of the uniformity of the in-plane carbon concentration in the Ni films before annealing, we observe thickness non-uniformities in the synthesized graphene layers after high temperature annealing. These non-uniformities are probably induced by the heterogeneous distribution/topography of the graphene nucleation sites on the Ni surface. Taken altogether, our results indicate that the number of graphene layers on top of Ni films is controlled by the nucleation process on the Ni surface rather than by the carbon content in the Ni film. 相似文献