Reduced-order model of proper orthogonal decomposition method (POD) was established to analyzed performance of fluid flow and heat transfer in flat tube bank fin heat exchanger. Numerical results of POD were compared with those of FVM. It indicates that average relative error between POD results and FVM results is no more than 5.7% while computational speed is improved 164.78-2021 times. Conclusion is of theoretical meaning for optimizing heat exchanger structure and running mode in engineering.

For problems that can be described by parameterized partial differential equations, reduced basis finite element constructs basis functions on top of typical high-fidelity solutions and thus greatly reduces number of unknowns. Principles of the method is introduced and favorable features are demonstrated through heat conduction problem and neutron diffusion problem. It shows speedup of three orders of magnitude during online stage.

Phases of antiferromagnetic magnetization and exchange bias and coercivity in ferromagnetic/antiferromagnetic/ferromagnetic(FM/AF/FM) trilayers with interface quadratic and biquadratic exchange coupling are studied comprehensively.Three possible cases are found,namely reversible recovering case,irreversible continuously-reversing case and irreversible discontinuously-reversing case. Realization of the cases strongly depends on pinned-M_FM interface quadratic exchange coupling J₁,free-M_FM interface quadratic exchange coupling J₂ and biquadratic coupling J'₂.In the reversible recovering,the exchange coupling results in an exchange bias,and there is no exchange bias in other cases.It provides possible explanation for both hysteresis energy loss and perpendicular coupling at the interface.