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81.
Xin Chen Aleksandra M. Krajewska Dr. Cormac McGuinness Amy Lynes David McAteer Nina Berner Prof. Georg Duesberg Prof. Jonathan N. Coleman Prof. Aidan R. McDonald 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(3):984-992
Covalently tethering photosensitizers to catalytically active 1T-MoS2 surfaces holds great promise for the solar-driven hydrogen evolution reaction (HER). Herein, we report the preparation of two new RuII-complex-functionalized MoS2 hybrids [RuII(bpy)2(phen)]-MoS2 and [RuII(bpy)2(py)Cl]-MoS2. The influence of covalent functionalization of chemically exfoliated 1T-MoS2 with coordinating ligands and RuII complexes on the HER activity and photo-electrochemical performance of this dye-sensitized system was studied systematically. We find that the photo-electrochemical performance of this RuII-complex-sensitized MoS2 system is highly dependent on the surface extent of photosensitizers and the catalytic activity of functionalized MoS2. The latter was strongly affected by the number and the kind of functional groups. Our results underline the tunability of the photovoltage generation in this dye-sensitized MoS2 system by manipulation of the surface functionalities, which provides a practical guidance for smart design of future dye-sensitized MoS2 hydrogen production devices towards improved the photofuel conversion efficiency. 相似文献
82.
Zhao Y Slepkov AD Akoto CO McDonald R Hegmann FA Tykwinski RR 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,11(1):321-329
Monodisperse, cross-conjugated perphenylated iso-polydiacetylene (iso-PDA) oligomers, ranging from monomer 15 to pentadecamer 25, have been synthesized by using a palladium-catalyzed cross-coupling protocol. Structural characteristics elucidated by X-ray crystallographic analysis demonstrate a non-planar backbone conformation for the oligomers due to the steric interactions between alkylidene phenyl groups. The electronic absorption spectra of the oligomers show a slight red-shift of the maximum absorption wavelength as the chain length increases from dimer 17 b to pentadecamer 25, a trend that has saturated by the stage of nonamer 22. Fluorescence spectroscopy confirms that the pendent phenyl groups present on the oligomer framework enhance emission, and the relative emission intensity consistently increases as a function of chain length n. The molecular third-order nonlinearities, gamma, for this oligomer series have been measured via differential optical Kerr effect (DOKE) detection and show a superlinear increase as a function of the oligomer chain length n. Molecular modeling and spectroscopic studies suggest that iso-PDA oligomers (n>7) adopt a coiled, helical conformation in solution. 相似文献
83.
A. Alessandrello C. Arnaboldi F. T. Avignone III J. Beeman M. Barucci M. Balata C. Brofferio C. Bucci S. Cebrian R. J. Creswick S. Capelli L. Carbone O. Cremonesi A. de Ward E. Fiorini H. A. Farach G. Frossati A. Giuliani D. Giugni E. E. Haller I. G. Irastorza R. J. McDonald A. Morales E. B. Norman P. Negri A. Nucciotti M. Pedretti C. Pobes V. Palmieri M. Pavan G. Pessina S. Pirro E. Previtali C. Rosenfeld A. R. Smith M. Sisti G. Ventura M. Vanzini L. Zanotti 《Physics of Atomic Nuclei》2003,66(3):452-457
CUORE is a proposed tightly packed array of 1000 TeO2 bolometers, each being a cube 5 cm on a side with a mass of 750 g. The array consists of 25 vertical towers, arranged in a square of 5 towers by 5 towers, each containing ten layers of four crystals. The design of the detector is optimized for ultralow-background searches for neutrinoless double beta decay of 130Te (33.8% abundance), cold dark matter, solar axions, and rare nuclear decays. A preliminary experiment involving 20 crystals of various sizes (MIBETA) has been completed, and a single CUORE tower is being constructed as a smaller scale experiment called CUORICINO. The expected performance and sensitivity, based on Monte Carlo simulations and extrapolations of present results, are reported. 相似文献
84.
On the Spectra of Striped Sign Patterns 总被引:4,自引:0,他引:4
J. J. McDonald D. D. Olesky M. J. Tsatsomeros P. van den Driessche 《Linear and Multilinear Algebra》2003,51(1):39-48
Sign patterns consisting of some positive and some negative columns, with at least one of each kind, are shown to allow any self-conjugate spectrum, and thus to allow any inertia. In the case of the n ×n sign pattern with all columns positive, given any self-conjugate multiset consisting of n -1 complex numbers supplemented by a sufficiently large positive number, it is shown how to construct a positive normal matrix whose spectrum is this multiset. Thus, the positive sign pattern allows any inertia with at least one positive eigenvalue. 相似文献
85.
O. Häusser T.K. Alexander D.L. Disdier A.J. Ferguson A.B. McDonald I.S. Towner 《Nuclear Physics A》1973,216(3):617-628
The α-decay of several unbound levels in 20Ne has been studied by 16O(α, α) elastic and inelastic scattering. A narrow resonance, Γc.m. = 13±4 eV, with Jπ = 5? was found at and is associated with the lowest K = 2? quasirotational band. Several new, narrow resonances were found between Ex = 16.0?18.4 MeV. Reduced α-decay widths have been obtained for the lowest K = 0+, 2? and 0?bands. For states described predominantly by the (8, 2) representation of SU(3) we note a reduction of the reduced widths with increasing spin. Reduced widths of positive parity bands are reviewed. 相似文献
86.
P. Darriulat P. Dittmann K. Eggert M. Holder K.T. McDonald T. Modis F.L. Navarria A. Seiden J. Strauss G. Vesztergombi E.G.H. Williams 《Nuclear Physics B》1976,107(3):429-456
We present a study of the final state structure in proton-proton collisions (√s = 53 GeV) where a large transverse momentum π0 (pt > 2 GeV/c) is produced at an angle of 90°. Charged secondaries have been detected and momentum analysed in the split field magnet detector at the CERN Intersecting Storage Rings. The large angular coverage of this detector extends over ±2.5 units of rapidity and ±30° of azimuth with respect to the trigger π0, both towards and away from it. In each of these directions, where we observe similar strong correlations, we present charged particle distributions, in rapidity and momentum. In the hemisphere containing the trigger π0 we have measured the cross section for inclusive production of large transverse momentum ?± mesons. In the opposite hemisphere the data exhibit several features predicted by hard scattering quark-parton models: coplanarity and short-range rapidity correlation for the large transverse momentum secondaries as well as a transverse momentum sharing distribution similar to that observed in deep inelastic electro-production and in e+e? collisions. 相似文献
87.
Ruthenium shows promise for use as a chemical modifier for the determination of ultratrace quantities of lead in solution when compared with the popular and widely used palladium. There is experimental evidence that ruthenium reacts with lead in the graphite tube to form the intermetallic compound PbRu2. The amount of ruthenium had a dramatic effect on the absorbance profile for the lead signal. 相似文献
88.
89.
S. Thore S. L. McDonald R. Gonzalez N. P. Ritchey T. W. Ruefli K. K. Sinha 《Annals of Operations Research》1996,68(3):409-422
The gradual exhaustion of existing deposits of a depletable non-renewable resource such as oil tends to shift the supply price curve of the resource upwards, increasing its marginal cost. Advances in technologies for exploration and production act as a brake on such upward shifts. Thus, there is a tug-of-war between the gradual exhaustion of existing deposits and technological progress. Using a recently developed constrained least-squares regression technique, we demonstrate that technological progress was the dominant force of the two during the first part of this century, causing a secular drop in marginal costs, but that this situation eventually was reversed, and that the gradual exhaustion of deposits gained the upper hand, causing marginal costs to increase. The turning point occurred around 1971–72. We also discuss the forecasting of the possible current upward drift of marginal costs. 相似文献
90.