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181.
Amorphous Fe67?xC10B9Mo7+xCr4W3 (x = 1–7 at.%) plates with 0.64 mm thickness were prepared by copper mold casting. The thermal properties and microstructural development during heat treatments were investigated by a combination of differential scanning calorimetry, differential thermal analysis, and X-ray diffraction. The glass forming ability (GFA) and activation energy for crystallization have a distinct dependence on Mo content. Fe62C10B9Mo12Cr4W3 was the best glass former in this study, demonstrating a supercooled liquid region, ΔTx = 51 K, and an activation energy for crystallization, Q = 453 kJ/mol. The GFA of alloys in this system was governed by elastic strain optimization resulting directly from the variation in Mo content. Heat treatments were performed to demonstrate resistance to crystallization under typical processing conditions. Alloys in this system exhibited a three phased evolution during crystallization. A second set of heat treatments was performed to identify each phase. An analysis of phase evolution revealed a distinct dependence of phase evolution with stepwise substitution of Mo for Fe in this system. 相似文献
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Potential Analysis - We construct a family of steady solutions of the lake model perturbed by some small Coriolis force, that converge to a singular vortex pair. The desingularized solutions are... 相似文献
183.
Unprecedented Oxidative Addition and Metal‐Only Lewis Pair Chemistry of Antimony Trihalides
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Prof. Dr. Holger Braunschweig Dr. Rian D. Dewhurst Florian Hupp Dr. Justin Wolf 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(5):1860-1862
Reaction of the zero‐valent platinum complex [Pt(PCy3)2] with SbF3 generates the cationic diplatinum stibenium complex [{(Cy3P)2Pt}2(μ‐SbF2)]+, the first unsupported metal‐only Lewis pair containing an antimony‐centered Lewis acid. In contrast, SbCl3 undergoes oxidative addition to [Pt(PCy3)2], resulting in the dihalostibanyl complex trans‐[PtCl(SbCl2)(PCy3)2], the first example of oxidative addition of an antimony–halide bond to a transition metal. 相似文献
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Rebeca G. Castillo Justin T. Henthorn Jeremy McGale Dimitrios Maganas Serena DeBeer 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(31):13065-13075
In recent years, X-ray emission spectroscopy (XES) in the Kβ (3p-1s) and valence-to-core (valence-1s) regions has been increasingly used to study metal active sites in (bio)inorganic chemistry and catalysis, providing information about the metal spin state, oxidation state and the identity of coordinated ligands. However, to date this technique has been limited almost exclusively to first-row transition metals. In this work, we present an extension of Kβ XES (in both the 4p-1s and valence-to-1s [or VtC] regions) to the second transition row by performing a detailed experimental and theoretical analysis of the molybdenum emission lines. It is demonstrated in this work that Kβ2 lines are dominated by spin state effects, while VtC XES of a 4d transition metal provides access to metal oxidation state and ligand identity. An extension of Mo Kβ XES to nitrogenase-relevant model complexes shows that the method is sufficiently sensitive to act as a spectator probe for redox events that are localized at the Fe atoms. Mo VtC XES thus has promise for future applications to nitrogenase, as well as a range of other Mo-containing biological cofactors. Further, the clear assignment of the origins of Mo VtC XES features opens up the possibility of applying this method to a wide range of second-row transition metals, thus providing chemists with a site-specific tool for the elucidation of 4d transition metal electronic structure. 相似文献
185.
The Carbon sphere@Nickel sulfide core-shell nanocomposites for different mole ratios of Carbon sphere (0:1; 0.5:1 and 1:1) have been synthesized by a facile low temperature water-bath method without any further calcination. XRD studies on the core-shell nanocomposites show that characteristic peaks associated with rhombohedral phase structure of nickel sulfide have been retained. TEM morphology presents the interlinked core-shell of Carbon sphere@Nickel sulfide composite with grass-leaf dexterity for better ionic diffusion. BET study confirms the formation of mesoporous structure with high surface area. The existence of elements and its electronic configuration is noted through XPS. The electrochemical studies on pristine nickel sulfide and its Carbon sphere@Nickel sulfide core-shell composites reveal that Carbon sphere@Nickel sulfide (0.5:1) exhibits high specific capacitance of 1022?F?g?1 at a current density of 1?A?g?1. It shows good cyclic performance even beyond 4000 consecutive charge/discharge cycles at a relatively high current density of 20?A?g?1 with the ~83% of retention. 相似文献
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Christian W. Pester Justin E. Poelma Benjaporn Narupai Shrayesh N. Patel Gregory M. Su Thomas E. Mates Yingdong Luo Christopher K. Ober Craig J. Hawker Edward J. Kramer 《Journal of polymer science. Part A, Polymer chemistry》2016,54(2):253-262
In an attempt to create a polymer brush-based platform for the systematic study for anti-biofouling surfaces, the benefits of surface initiated, visible light-mediated radical polymerization are utilized to fabricate well-defined, chemically ambiguously patterned surfaces. A variety of analytical tools are used to illustrate the precise tuning of surface chemistry and thoroughly characterize spatially well-defined, hydrophilic/hydrophobic surfaces composed of poly(ethylene glycol methacrylate) and poly(trifluoroethyl methacrylate) with chemical definition on the micron scale. Advantages of both visible light-mediated photopolymerization and traditional copper-catalyzed atom transfer radical polymerization are combined to achieve both high spatial control and expanded monomer tolerance. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016, 54, 253–262 相似文献
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