A mathematical model is established to describe convective heat transfer in magnetic microencapsulated phase change material slurry (MMPCMS) flows in a circular tube under an external magnetic field. Influences of magnetic field strength, volume fraction of magnetic phase change materials (MMPCM), mass flow rate, and heat flux on convective heat transfer are analyzed. It shows that convective heat transfer of slurries is obviously enhanced by external magnetic field. Since distributions of MMPCM volume fraction and slurry temperature are changed clue to magnetic force on MMPCM.

Defect modes in a photonic crystal slab cavity are calculated with finite difference time domain method and group theory. Using symmetry boundary eondition.all frequencies of defect modes are obtained through dipole driving-sources with a broadband pulse.For one given frequency of defect mode,we use narrowband pulse to excite one single defect mode.Numerical results show that all defect modes with different symmetries can be obtained with this method.

A ray split-off and tracing approach is presented to analyze the apparent spectral reflecting performance of a semitransparent fluid layer with undulant surface.For parallel incidence and diffuse incidence of the spectral radiation,the regular ray tracing and the inverse ray tracing are separately employed to realize tracing the ray split-off process.With a clear and simple solving idea, the approach possesses a high calculating rate and small demands for the EMS memory,and is flexible for this kind of problems.The results of the calculating example show the following facts.For diffuse incidence of the spectral radiation,the undulant curve of the surface lowers the reflecting ability of the fluid layer.While for parallel incidence of the spectral radiation,two kinds of different influences on the reflecting ability may be caused by the undulant curve.

According to the internal thermal emission of the medium,a new method,pseudo source adding method,is presented to analyze the apparent emissivities of semi-transparent medium layers.By this method,the apparent emissivity formulae are derived for two different cases,in one of which,the semi-transparent emitting surface is considered to be specularly reflecting,and the diffuse reflection is considered in the other.The substrate surface of the layer is supposed to be diffuse and opaque for the two cases.The comparison with the results by the Monte Carlo method is also given.