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21.
Bhowmick R Rajasekaran S Friebel D Beasley C Jiao L Ogasawara H Dai H Clemens B Nilsson A 《Journal of the American Chemical Society》2011,133(14):5580-5586
Using in situ electrical conductivity and ex situ X-ray photoelectron spectroscopy (XPS) measurements, we have examined how the hydrogen uptake of single-walled carbon nanotubes (SWNTs) is influenced by the addition of Pt nanoparticles. The conductivity of platinum-sputtered single-walled carbon nanotubes (Pt-SWNTs) during molecular hydrogen exposure decreased more rapidly than that of the corresponding pure SWNTs, which supports a hydrogenation mechanism facilitated by "spillover" of dissociated hydrogen from the Pt nanoparticles. C 1s XPS spectra indicate that the Pt-SWNTs store hydrogen by means of chemisorption, that is, covalent C-H bond formation: molecular hydrogen charging at elevated pressure (8.27 bar) and room temperature yielded Pt-SWNTs with up to 16 ± 1.5 at. % sp(3)-hybridized carbon atoms, which corresponds to a hydrogen-storage capacity of 1.2 wt % (excluding the weight of Pt nanoparticles). Pt-SWNTs prepared by the Langmuir-Blodgett (LB) technique exhibited the highest Pt/SWNT ratio and also the best hydrogen uptake. 相似文献
22.
L. B. Beasley A. E. Guterman K.-T. Kang S.-Z. Song 《Journal of Mathematical Sciences》2008,152(4):456-468
We obtain a new structural characterization of idempotent Boolean matrices. This characterization allows us to describe all
Boolean matrices that are majorized by a given idempotent.
__________
Translated from Fundamentalnaya i Prikladnaya Matematika, Vol. 13, No. 1, pp. 11–29, 2007. 相似文献
23.
Oxide-layer tunnel junctions exhibiting both quasi-particle and Josephson tunneling were produced by overlaying lead on niobium-tin thin films. The superconducting transition temperature and average energy gap of the Nb-Sn both increased as the tin concentration was increased toward Nb3Sn and reached maximum values of 17.2 K and 3.2 meV, respectively, or 2Δ = 4.3 kTc. 相似文献
24.
In this paper we present a lower bound for the capacitated warehouse location problem based upon the Lagrangean relaxation of a mixed-integer formulation of the problem, where we use subgradient optimisation in an attempt to maximise this lower bound. Problem reduction tests based upon this lower bound and the original problem are given. Incorporating this bound and the reduction tests into a tree search procedure enables us to solve problems involving up to 50 warehouses and 150 customers. 相似文献
25.
LeRoy B. Beasley Young Bae Jun Seok-Zun Song 《Czechoslovak Mathematical Journal》2018,68(4):1055-1066
Let ?+ be the semiring of all nonnegative integers and A an m × n matrix over ?+. The rank of A is the smallest k such that A can be factored as an m × k matrix times a k×n matrix. The isolation number of A is the maximum number of nonzero entries in A such that no two are in any row or any column, and no two are in a 2 × 2 submatrix of all nonzero entries. We have that the isolation number of A is a lower bound of the rank of A. For A with isolation number k, we investigate the possible values of the rank of A and the Boolean rank of the support of A. So we obtain that the isolation number and the Boolean rank of the support of a given matrix are the same if and only if the isolation number is 1 or 2 only. We also determine a special type of m×n matrices whose isolation number is m. That is, those matrices are permutationally equivalent to a matrix A whose support contains a submatrix of a sum of the identity matrix and a tournament matrix. 相似文献
26.
J. E. Beasley R. L. Anderson J. P. Dickie F. R. Dollish E. C. Tynan Teh Fu Yen 《光谱学快报》2013,46(5):149-156
A Digital Equipment Corporation PDP 8/S Computer is interfaced with an EPR Spectrameter to achieve signal enhancement. A computer-based system for spectrum accumulation and noise averaging of EPR or NMR signals has been designed and implemented. The computer-based system was chosen over other perhaps more conventional systems because of its greater flexibility in the processing of spectra, especially after the accumulation is complete.(1) 相似文献
27.
28.
We have experimentally investigated the density of states (DOS) in Nb/Ni (S/F) bilayers as a function of Ni thickness, d(F). Our thinnest samples show the usual DOS peak at +/- Delta(0), whereas intermediate-thickness samples have an anomalous "double-peak" structure. For thicker samples (d(F) > or =3.5 nm), we see an inverted DOS, which has previously only been reported in superconductor or weak-ferromagnet structures. We analyze the data using the self-consistent nonlinear Usadel equation and find that we are able to quantitatively fit the features at +/- Delta(0) -- in particular the thickness at which the inversion occurs -- only if we include a large amount of spin-orbit scattering in the model. Interestingly, we are unable to reproduce the subgap structure through the addition of any parameter(s). Therefore, the observed anomalous subgap structure represents new physics beyond that contained in the present Usadel theory. 相似文献
29.
We obtain a complete characterization of surjective additive operators acting on the Cartesian product of several matrix spaces over an antinegative semiring without zero divisors, which map primitive matrix k-tuples to primitive matrix k-tuples. 相似文献
30.
PD McCrary PA Beasley SP Kelley S Schneider JA Boatz TW Hawkins JP Perez BW McMahon M Pfiel SF Son SL Anderson RD Rogers 《Physical chemistry chemical physics : PCCP》2012,14(38):13194-13198
The passivation and stability of suspensions of titanium nanoparticles in azolium azolate ionic liquids can be tuned by introducing metal specific binding sites in the azolate anion. 相似文献