We propose a digital image encryption algorithm based on conservative hyperchaotic signals. Based upon a 5-dimensional conservative hyperchaotic system, the algorithm generates a 5-channel time series to perform scrambling in both pixel-level and bit-level, and subsequently an XOR operation on scrambled RGB components of the original image. On this basis, an encrypted image is obtained with time series of one of the channels to perform a forward XOR operation and S-BOX processing, a reverse XOR operation, S-BOX processing, and scrambling. Finally, the encryption algorithm is evaluated with several security indicators such as histogram, information entropy, and key space. Performance of the encryption algorithm in digital image encryption is compared with that of a 5-dimensional dissipative hyperchaotic system. It shows that the algorithm based on conservative chaos has higher safety and reliability.

AMY is a newly-developed code of handling neutron induced transmutation and activation in materials. The code is based on Chebyshev rational approximation method (CRAM) to solve Bateman equations and to deal with complex pattern of chains produced by sequences of neutron reaction processes.Varieties of material activation properties are provided in AMY, including activity, decay heat, biological hazard, dose rate, clearance index and gamma source spectra. In order to verify the code, basic nuclear database in handbook of activation data was selected for comparing with FISPACT-2007. It shows that results of AMY are in good agreement with FISPACT-2007, and calculation efficiency of AMY is slightly higher than FISPACT-2007.

Isogeometric analysis(IGA) is applied to eigenvalue problem of waveguide with arbitrary cross-section.Weakened equations are involved with NURBS elements from governing equation of waveguide.The computational model in IGA is inherited from a design model in CAD system,which is beyond traditional numerical method with remodeling procedure.Elliptical waveguides with various eccentricities,triangular and pentagon waveguides are addressed as numerical examples.It demonstrates that the preseut method is feasible for eigenvalue analysis of waveguide with either elliptical or polygonal cross-section.Moreover,it yields excellent results with fewer DOFs,and obtains quicker convergence than traditional method.

We propose a layer-oriented integration arithmetic for conformal perfectly matched layer (CPML).It reduces number of element and computational scale by superposing multilayer integration to monolayer integration.To retain geometrical and material information of multilayer elements we mesh CPML by multilayer elements and calculate element matrixes by monolayer integration.Numerical examples show that layer-oriented integration CPML is a reliable and high-efficient absorbing boundary condition.

A reordering method,named alternate hyperplane ordering,is proposed to solve linear systems from two-dimension three-temperature nonlinear energy equations.Numerical experiments are performed with Krylov subspace iterative associated ILU(k) preconditioning.It is showed that with nearly same preconditioning cost,the proposed ordering method is better than red-black ordering and hyperplane ordering etc.

Based on incomplete Cholesky decomposition with two thresholds,we propose an improved incomplete Cholesky conjugate gradient (ICCG) method with diagonal elements modification.It ensures accurate and efficient decomposition and solution of large scale sparse linear equations. The method shows advantage in computing time and storage requirment.It is applicable to solve the systems of linear equations from FEM finite element method.

Numerical simulations of two-dimensional laser driven implosion with spherical coordinates and the relative computational methods are mainly summarized.Features of solving the hydrodynamic equations by the fully conservative implicit difference scheme and solving the thermal conductive equations by the variational method are discussed.Eexamples of relative physical models are presented and effects of the non-symmetry on the laser driven implosive processes are examined.

Difference numerical simulation for two dimensional thermal conduction equation is studied.Using the variational principle,the difference scheme with thermal-flux form in the irregular structured mesh is presented.The thermal flux as an unknown function is obtained by minimizing the functional and solved with the equation of temperature function simultaneously.This scheme overcomes the defects of general nine-point schemes,which have to calculate the thermal conduction coefficients on the cell boundaries and the temperatures located in the cell vertices by interpolation.