486 research outputs found
Two new xanthone glycosides from Swertia tetraptera
No full textTwo new xanthone glycosides, tetraswerosides A and B, were isolated from the whole plant of Swertia tertraptera. Their structures were determined as 3-O-beta -D-glucopyranosyl-1-hydroxy-4,7-dimethoxyxanthone and 3-O-[beta -D-xylopyranosyl-(1-->6)-beta -D-glucopyranosyl]-1- hydroxy-4,7-dimethoxyxanthone by spectroscopic methods
Superdense Coding with GHZ and Quantum Key Distribution with W in the ZX-calculus
Get PDFQuantum entanglement is a key resource in many quantum protocols, such as quantum teleportation and quantum cryptography. Yet entanglement makes protocols presented in Dirac notation difficult to verify. This is why Coecke and Duncan have introduced a diagrammatic language for quantum protocols, called the ZX-calculus. This diagrammatic notation is both intuitive and formally rigorous. It is a simple, graphical, high level language that emphasises the composition of systems and naturally captures the essentials of quantum mechanics. In the author's MSc thesis it has been shown for over 25 quantum protocols that the ZX-calculus provides a relatively easy and more intuitive presentation. Moreover, the author embarked on the task to apply categorical quantum mechanics on quantum security; earlier works did not touch anything but Bennett and Brassard's quantum key distribution protocol, BB84. Superdense coding with the Greenberger-Horne-Zeilinger state and quantum key distribution with the W-state are presented in the ZX-calculus in this paper
A new sesquiterpene lactone of Notoseris henryi
No full textA new guaianolide, notoserolide E, along with nine known compounds was isolated from the Chinese endemic plant of Notoseris henryi ( Dunn) Shih and its structure was elucidated by means of spectroscopic evidence
The glycosides from Lomatogonium rotatum
No full textA new phenyl glycoside, 2-(3'-O-beta-D-glucopyranosyl) benzoyloxygentisic acid (1), along with seven known glycosides 2-8 was isolated from Tibetan herbal medicine Lomatogonium rotatum. The structures of the compounds were elucidated by spectroscopic methods including 1D and 2D NMR techniques and MS data
Twinning partial multiplication at grain boundary in nanocrystalline fcc metals
No full textMost deformation twins in nanocrystalline face-centered cubic fcc metals have been observed to form from grain boundaries. The growth of such twins requires the emission of Shockley partials from the grain boundary on successive slip planes. However, it is statistically improbable for a
partial to exist on every slip plane. Here we propose a dislocation reaction and cross-slip mechanism on the grain boundary that would supply a partial on every successive slip plane for twin growth.This mechanism can also produce a twin with macrostrain smaller than that caused by a conventional twin
Investigation of absorption of nanocrystalline silicon
No full textNanocrystalline silicon embedded SiO2 matrix is formed by annealing the SiO2 films fabricated by plasma enhanced chemical vapor deposition technique. In conjunction with the micro-Ramam spectra, the absorption spectra of the films have been investigated. The blue-shift of absorption edge with decreasing size of silicon crystallites is due to quantum confinement effect. It is found that nanocrystalline silicon is of an indirect band structure, and that the absorption presents an exponential dependance absorption coefficient on photon energy ii! the range of 2.0-3.0 eV, and a sub-band appears in the the range of 1.0-1.5 eV. We believe that the exponential absorption is due to the indirect band-to-band transition of electrons in silicon nanocrystallites, while the Sub-band absorption is ascribed to transitions between the amorphous silicon states existing in the films
Absorption spectra of nanocrystalline silicon embedded in SiO2 matrix
No full textNanocrystalline silicon (nc-Si) embedded SiO2 matrix has been formed by annealing the SiOx films fabricated by plasma-enhanced chemical vapor deposition (PECVD) technique. Absorption coefficient and photoluminescence of the films have been measured at room temperature. The experimental results show that there is an "aUrbach-like" b exponential absorption in the spectral range of 2.0-3.0 eV. The relationship of (alpha hv)(1/2) proportional to(hv - E-g) demonstrates that the luminescent nc-Si have an indirect band structure. The existence of Stokes shift between photoluminescence and absorption edge indicates that radiative combination can take place not only between electron states and hole states but also between shallow trap states of electrons and holes. (C) 2000 Elsevier Science B.V. All rights reserved
On-top pair-correlation function in the homogeneous electron liquid
No full textThe ladder theory, in which the Bethe-Goldstone equation for the effective potential between two scattering particles plays a central role, is well known for its satisfactory description of the short-range correlations in the homogeneous electron liquid. By solving exactly the Bethe-Goldstone equation in the limit of large transfer momentum between two scattering particles, we obtain accurate results for the on-top pair-correlation function g(0), in both three dimensions and two dimensions. Furthermore, we prove, in general, that the ladder theory satisfies the cusp condition for the pair-correlation function g(r) at zero distance r=0.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000235009500047&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Physics, Condensed MatterSCI(E)8ARTICLE3null7
Improved fifth-order geometric aberration coeincients of electron lenses
No full textIn this paper, fifth-order geometric aberrations of round electron lenses have been restudied. Improved analytical formulae of the aberration coefficients were derived by the computer algebra software-Mathematica-and their correctness verified by cross-checking with numerical integration and differential algebraic techniques for a given electromagnetic lens.Physics, AppliedSCI(E)EI3ARTICLE5653-6593
Long-wavelength behavior of the dynamical spin-resolved local-field factor in a two-dimensional electron liquid
No full textThe high-frequency limits of the singular component A(omega) of the small wave-vector expansion of the longitudinal (L) and transverse (T) components of the spin-resolved exchange-correlation kernel tensor f(xc,sigmasigma)('L,T)(q,omega)=-v(q)G(sigmasigma)('L,T)(q,omega) in a two-dimensional isotropic electron liquid with arbitrary spin polarization are studied. Here G(sigmasigma)('L,T)(q,omega) is the spin-resolved local-field factor, v(q) is the Coulomb interaction in momentum space, and sigma denotes spin. Particularly, the real part of A(omega) is found to be logarithmically divergent at large omega. The large wave-vector structure of the corresponding spin-resolved static structure factor is also established.Physics, Condensed MatterSCI(E)1ARTICLE23null7
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