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Sichuan, China

Jin J.,Sichuan University
Optics and Lasers in Engineering | Year: 2012

This paper presents a new image encryption/decryption scheme. The behavior of a number of elementary cellular automata (ECA) of length 8 with periodic boundary conditions is investigated. It is found in the state-transition diagram that some ECA rules result in state attractors which satisfies basic requirement of the encryption scheme that can perform encrypting function to transform the pixel values. The generation of these attractors depending only on the rule and initial state of the CA, without any additional hardware cost for the implementation, and requires minimized computational resources. Simulation results on some grayscale and color images show that the proposed image encryption method satisfies the properties of confusion and diffusion, execution speed and has perfect information concealing. © 2012 Elsevier Ltd. Source


Fu Z.,Sichuan University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2013

The s-wave pion-pion (ππ) scattering lengths are computed below the inelastic threshold by the Lüscher technique with pion masses ranging from 240 to 463 MeV. In the Asqtad-improved staggered fermion formulation, we calculate the ππ four-point functions for the I=0 and 2 channels with "moving" wall sources without gauge fixing, and we analyze them at the next-to-leading order in the continuum three-flavor chiral perturbation theory. At the physical pion mass, we secure the s-wave ππ scattering lengths as mπaππI=0=0.214(4)(7) and mπaππI=2=-0. 04430(25)(40) for the I=0 and 2 channels, respectively, where the first uncertainties are statistical and the second ones are our estimates of several systematic effects. Our lattice results for the s-wave ππ scattering lengths are in good accordance with available experimental reports and theoretical forecasts at low momentum. A basic ingredient in our study for the I=0 case is properly incorporating the disconnected diagram. These lattice computations are carried out with the MILC 2+1 flavor gauge configurations at two lattice spacings, a≈0.15 and 0.12 fm. © 2013 American Physical Society. Source


Fu Z.,Sichuan University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

A proposal by Lüscher enables us to extract the elastic scattering phases from two-particle energy spectrum in a cubic box using lattice simulations. Rummukainen and Gottlieb further extend it to the moving frame, which is devoted to the system of two identical particles. In this work, we generalize Rummukainen-Gottlieb's formula to the generic two-particle states where two particles are explicitly distinguishable, namely, the masses of the two particles are different. Their relations with the elastic scattering phases of two-particle energy spectrum in the continuum are obtained for both C 4v and C 2v symmetries. Our analytical results will be very helpful for the study of some resonances, such as kappa, vector kaon, and so on. © 2012 American Physical Society. Source


Fu Z.,Sichuan University
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

The s-wave pion-kaon (πK) scattering lengths at zero momentum are calculated in lattice QCD with sufficiently light u/d quarks and strange quark at its physical value by the finite size formula. The light quark masses correspond to m π=0.330-0.466GeV. In the Asqtad improved staggered fermion formulation, we measure the πK four-point correlators for both the isospin I=1/2 and 3/2 channels, and analyze the lattice simulation data at the next-to-leading order in the continuum three-flavor chiral perturbation theory, which enables a simultaneous extrapolation of πK scattering lengths at the physical point. We adopt a technique with the moving wall sources without gauge fixing to obtain substantiable accuracy; moreover, for the I=1/2 channel, we employ the variational method to isolate the contamination from the excited states. Extrapolating to the physical point yields the scattering lengths as m πa 3/2=-0.0512(18) and m πa 1/2=0.1819(35) for the I=3/2 and 1/2 channels, respectively. Our simulation results for πK scattering lengths are in agreement with the experimental reports and theoretical predictions, and can be comparable with other lattice simulations. These simulations are carried out with MILC N f=2+1 flavor gauge configurations at lattice spacing 0.15fm. © 2012 American Physical Society. Source


Yao J.,University of Sichuan | Yang M.,University of Sichuan | Duan Y.,University of Sichuan | Duan Y.,Sichuan University
Chemical Reviews | Year: 2014

The combination of fluorescence and nanomaterials has developed into an emerging research area: fluorescent nanoparticles. Nanomaterials are at the leading edge of the rapidly developing field of nanotechnology and have attracted increasing interest for bioanalytical labeling applications in recent years. The emerging development and innovation of luminescent nanoparticles (NP) with unique optical properties, yet complicated surface chemistry, paves new roads for fluorescence imaging and sensing as well as for in vitro and in vivo labeling in cells, tissues, and organisms. The labeling procedure can be straightforward provided that suitable functional groups are available on the target analyte. However, it can be difficult to reach a low detection limit in fluorescence detection due to the limited extinction coefficients or quantum yields of traditional organic dyes and also low dye-to-reporter molecule labeling ratio. Source

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