In an elastic mechanics model,a magnetoelectric composites constitutive equation was established. Longitudinal and transverse ME voltage coefficient formulas of double-layer and three-layer composited thin films of 2-2 type in non-ideal condition were deduced with ferroelectric and magnetic constitutive equation. Composite ME voltage coefficient of ferromagnetic phase material nickel ferrite (NFO) and ferroelectric phase material lead magnesium niobate-lead titanate (PMNT) are studied. Relations between ME voltage coefficient and PMNT volume fraction,interface coupling parameters,two phase volume ratio and total number of layers are analyzed. It shows that performance of two phase material,appropriate volume fraction,coupling coefficient and total layer number are key to ME voltage coefficient.

An empirical potential of binary molecular clusters of (NH₃)_m(H₂O)₄ is proposed.Stable model structures of NH₃(H₂O)₄ are optimized by using a fast molecular dynamics algorithm.The optimal structures are refined by using conventional ab initio optimization method.Optimization and frequency calculations are carried out at different levels of density functional theory (DFT/B3LYP) and Mller-Plesset second-order perturbation method(MP2) with 6-311++G** basis set.It is found that stable model structures remain the minima at B3LYP and MP2 levels.12 new ab initio stable isomers of NH₃(H₂O)₄,including the second and third ones are obtained.The results show that there is no inevitable relevancy between stability and dipole moment,and the number of hydrogen bonds of isomers.