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71.
Ohne Zusammenfassung 相似文献
72.
In presence of tin(II) bromide, noble metals give coloured products which are suitable for spcctrophotometric determinations. The colours are red (platinum), yellow-orange (rhodium), yellow-brown (palladium), yellow (iridium) and violet (gold) They are extracted, except for gold, with isoamyl alcohol Platinum, rhodium and palladium can be separated from irdium, and rhodium and platinum from palladium. Rhodium and platinum can be determined simultaneously. 相似文献
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Francesco Calogero 《Journal of Nonlinear Mathematical Physics》2016,23(4):486-493
New solvable dynamical systems are identified and the properties of their solutions are tersely discussed. 相似文献
77.
Ermete Antolini Leonardo Giorgi Francesco Cardellini Enza Passalacqua 《Journal of Solid State Electrochemistry》2001,5(2):131-140
Platinum-ruthenium catalysts supported on carbon (PtRu/C) have been characterized by X-ray diffraction (XRD), transmission
electron microscopy (TEM), specific surface area analysis (BET), X-ray photoelectron spectroscopy (XPS) and in proton exchange
membrane (PEM) fuel cell tests. The results indicate the presence of strong metal-carbon interactions, which hinder the formation
of a single-phase face-centered cubic (fcc) PtRu alloy. The particle size of the PtRu/C catalysts was smaller than both carbon-supported
platinum (Pt/C) and ruthenium (Ru/C) catalysts. In the bimetallic electrocatalysts the intercrystallite distance decreased
with respect to pure Pt and Ru metals. PEM fuel cell tests in H2/air operation mode revealed a decrease of performance with increasing carbon content of the catalyst, at a fixed Pt loading.
In H2 + 100 ppm CO/air operation mode the maximum performance of the PEM fuel cell was attained at 0.63 atomic fraction Ru.
Received: 2 December 1999 / Accepted: 27 January 2000 相似文献
78.
Francesco Demartin Fabrizia Fabrizi de Biani Cristina Femoni Maria Carmela Iapalucci Giuliano Longoni Piero Macchi Piero Zanello 《Journal of Cluster Science》2001,12(1):61-74
The [Ni36Pt4(CO)45]6- and [Ni37Pt4(CO)46]6- clusters have been obtained in mixture upon reaction in acetonitrile of [Ni6(CO)12]2- salts with K2PtCl4 in a 2.5:1 molar ratio. The two hexaanions were indistinguishable by spectroscopic techniques. Crystallization of their trimethylbenzylammonium salts led to crystals of composition 0.5[NMe3CH2Ph]6[Ni36Pt4(CO)45]-0.5[NMe3CH2Ph]6[Ni37Pt4(CO)46]·C3H8O, hexagonal,space group P63 (No. 173), a=17.853(9), c=27.127(13) Å, Z=2; final R=0.057. The metal core of the [Ni36Pt4(CO)45]6- anion consists of a Pt4 tetrahedron fully encapsulated in a shell of 36 Ni atoms belonging to a very distorted and incomplete 5 tetrahedron. The [Ni37Pt4(CO)46]6- hexaanion derives from the former by capping the unique triangular face of the metal polyhedron with an additional Ni(CO) fragment. The [Ni36Pt4(CO)45]6--[Ni37Pt4(CO)46]6- mixture is rapidly degraded to the known [Ni9Pt3(CO)21]4- cluster by exposure to carbon monoxide. Its reaction with protic acids initially affords the corresponding [H6-nNi36Pt4(CO)45]n--[H6-nNi37Pt4(CO)46]n- (n=5, 4) derivatives, and eventually leads to rearrangement to the known [H6-n Ni38Pt6(CO)48]n- species. Both [Ni36Pt4(CO)45]6--[Ni37Pt4(CO)46]6- and [HNi36Pt4(CO)45]5--[HNi37Pt4(CO)46]5- mixtures have been chemically and electrochemically reduced to their corresponding [Ni36Pt4(CO)45]n--[Ni37Pt4(CO)46]n- (n=7–9) and [HNi36Pt4(CO)45]n--[HNi37Pt4(CO)46]n- (n=6–8) mixtures. 相似文献
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