With ²³⁵U fission source in thermal neutron reactor as radiation source, MCNP code is employed to simulate energy spectrum and to study shielding protect.It shows that for prompt neutron, emitting by ²³⁵U fission source, with energy more than 3 MeV, heavy metals materials have better shielding effect.However, light hydrogen materials performance better for neutrons with energy below 1MeV.For compounds-W/LiH, W/B₄C and TiH₂/W, shielding effect is best as weight ratios are W:LiH=19:1, W:B₄C=9:1, W:TiH₂=3:1.GA combined with MCNP code is employed to search optimized design of compounds, W/TiH₂/B₄C, TiH₂/Cu/Gd and TiH₂/B₄C/Gd, respectively.Weight fractions are calculated as shielding effect performance is best.Exponential decay relations between dose equivalent rate (10^-11Sv·h^-1) in tissues caused by neutron and gamma rays penetrating materials and thickness of materials can be expressed as 1.071exp (-0.187 8x), 1.077exp (-0.166 2x) and 1.608exp (-0.171 9x), respectively, where x is thickness of material in cm.

We describe an unsteady flow model of blood in arterioles of normal and tumor tissues,and show effect of external magnetic field on flow field of blood considering coupling of magnetic field and flow. Traditional single-phase model is modified by a discrete method,and dynamical simulation with a finite element route is used to investigate transmission of magnetic nano-drug in arteriole.The result indicates that the capture of nano-drug by magnetic field is entirely different from that of microdrug by magnetic field.The trajectoriy of nano-drug is primarily coincident with the streamline of blood flow.However,the effect of magnetic field on the blood flow is obvious due to the presence of magnetic nano-drug.Several whirlpools are formed near the magnet.In tumor arteriole these whirlpools stay for a long time and the magnetic nano-drug is efficiently captured by external magnetic field.