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991.
Fumio Kokai Naoki Tachi Keita Kobayashi Akira Koshio 《Applied Surface Science》2009,255(24):9622-9625
Three types of single-wall carbon nanohorn (SWNH) aggregates hybridized with carbon nanocapsules (CNCs) containing Fe3C, Co, or Ag were produced by laser vaporization of graphite mixed with Fe, Co, or Ag in Ar gas. Characterization by transmission electron microscopy revealed that although the three hybrid structures had different diameter distributions with average diameters of 96, 90, and 85 nm, respectively, their SWNH layers had similar thicknesses (17-18 nm on average). The diameter difference is explained by the sizes (16-24 nm on average) of the encapsulated CNCs, the formation of which depended on the carbon solubility of the three metals and the precipitation of the graphitic layers. In addition, there was a stronger correlation between the diameters of the hybrids and the thicknesses of the SWNH layers for the three types. We suggest that the formation mechanism of the three structures is based on the assembly of SWNHs around a molten metal-carbon particle with certain ranges of lengths and diameters, respectively. 相似文献
992.
关于T传递性与S负传递性之间关系 总被引:2,自引:2,他引:0
首先指出文献[1]中关于T传递性与S负传递性的两个不正确的结论,然后在不同的条件下对二者之间的关系进行详细的讨论。 相似文献
993.
Gerhard Jger 《Annals of Pure and Applied Logic》2007,150(1-3):19-39
We study and some of its most important extensions primarily from a proof-theoretic perspective, determine their consistency strengths by exhibiting equivalent systems in the realm of traditional set theory and introduce a new and interesting extension of which is conservative over . 相似文献
994.
Corrado Manara Vincenzo Marra Daniele Mundici 《Transactions of the American Mathematical Society》2007,359(4):1593-1604
Baker-Beynon duality theory yields a concrete representation of any finitely generated projective Abelian lattice-ordered group in terms of piecewise linear homogeneous functions with integer coefficients, defined over the support of a fan . A unimodular fan over determines a Schauder basis of : its elements are the minimal positive free generators of the pointwise ordered group of -linear support functions. Conversely, a Schauder basis of determines a unimodular fan over : its maximal cones are the domains of linearity of the elements of . The main purpose of this paper is to give various representation-free characterisations of Schauder bases. The latter, jointly with the De Concini-Procesi starring technique, will be used to give novel characterisations of finitely generated projective Abelian lattice ordered groups. For instance, is finitely generated projective iff it can be presented by a purely lattice-theoretical word.
995.
Brian Jefferies Gerald W. Johnson Lance Nielsen 《Mathematical Physics, Analysis and Geometry》2007,10(1):65-80
The spectral theorem for commuting self-adjoint operators along with the associated functional (or operational) calculus is
among the most useful and beautiful results of analysis. It is well known that forming a functional calculus for noncommuting
self-adjoint operators is far more problematic. The central result of this paper establishes a rich functional calculus for
any finite number of noncommuting (i.e. not necessarily commuting) bounded, self-adjoint operators A
1,..., A
n
and associated continuous Borel probability measures μ
1, ⋯, μ
n
on [0,1]. Fix A
1,..., A
n
. Then each choice of an n-tuple of measures determines one of Feynman’s operational calculi acting on a certain Banach algebra of analytic functions even
when A
1, ..., A
n
are just bounded linear operators on a Banach space. The Hilbert space setting along with self-adjointness allows us to extend
the operational calculi well beyond the analytic functions. Using results and ideas drawn largely from the proof of our main
theorem, we also establish a family of Trotter product type formulas suitable for Feynman’s operational calculi.
相似文献
996.
A. Teğmen T. Altanhan B. S. Kandemir 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,41(2):397-402
We calculate the Wigner distribution function for the
Calogero-Sutherland system which consists of harmonic and
inverse-square interactions. The Wigner distribution function is
separated out into two parts corresponding to the relative and
center-of-mass motions. A general expression for the relative
Wigner function is obtained in terms of the Laguerre polynomials
by introducing a new identity between Hermite and Laguerre
polynomials. 相似文献
997.
998.
Aji A. Anappara David Barate Jan Devenson Alexei Baranov 《Solid State Communications》2007,142(6):311-313
The optical response of the intersubband excitation of multiple InAs/AlSb quantum wells embedded in a planar semiconductor microcavity has been studied through angle-dependent reflectance measurements. Using a resonator based on total internal reflection, a strong coupling is demonstrated between the intersubband optical transition and the cavity photon, with the attendant formation of intersubband polaritons. A giant vacuum-Rabi splitting 2ΩR was observed both at liquid helium temperatures () as well as at 300 K (), for a transition energy . The observed ratio is a record high value (14%) for any strongly-coupled systems, and demonstrates the huge potential of this material for the achievement of the ultra-strong coupling regime predicted theoretically. 相似文献
999.
The structure and diameter of the densely aligned carbon nanotubes (CNTs) by surface decomposition of C-face in vacuum were investigated by cross-sectional, plan-view transmission electron microscopy and electron diffraction methods. Zigzag-type CNTs were confirmed to be selectively formed and the formation mechanism was proposed from crystallographic analysis. Furthermore, the wall number of CNTs was found to be directly proportional to the diameter of CNTs. Comparing with the theoretical calculation, it was revealed that all of the carbon atoms remained on the surface after the selective evaporation of Si atoms by decomposition of each monolayer of , and then constructed the CNT walls with the minimum diffusion distance at the interface. 相似文献
1000.
We present a dissipative particle dynamics (DPD) approach for simulating the realignment of a nematic nanodroplet suspended
in an isotropic fluid following a switch in the direction of an applied external magnetic field. The interaction of the mesogens
with the external field is weak relative to the inter-molecular interactions. The simulations were used to investigate the
way orientational equilibrium is re-established. The results reveal that the realignment process of the nanodroplet is consistent
with its fluid structure. The reorientation of the nanodroplet as a whole is found to be caused by an internal structural
rearrangement rather than a coherent rotation of the centres of mass of the mesogens about the centre of the nanodroplet.
The switch in the field direction furthermore is found to induce a transient spatial variation in the orientational order
of the long axes of the mesogens: the orientational order parameters decreases on moving from the core of the nanodroplet
to the surface in contact with the isotropic environment. The results highlight differences between the time evolution of
the orientation of the long molecular axes in the field and the rotations of the centres of mass of the mesogens about the
centre of the nanodroplet. 相似文献