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Free-radical solution copolymerization of acrylonitrile (AN) with four comonomers including itaconic acid (IA), acrylamide (AM), methyl acrylate (MA) and ammonium salt of itaconic acid (AIA) were carried out respectively. Every copolymerization process has been named as AN/IA system, AN/AM system, AN/MA system and AN/AIA system respectively, and the attained polymer is regarded as AN/IA, AN/AM, AN/MA and AN/AIA copolymer respectively. Effect of different comonomers on the polymerization kinetics and viscosity of the spinning drop are discussed in detail. The exothermic reaction of polyacrylonitrile (PAN) precursors is determined by differential scanning calorimetry (DSC), and effect of the different comonomers on the stabilization exotherm properties of PAN precursors were also studied. It has been shown that the rate of polymerization decreases distinctly with an increase of IA content, the ammonium modification can obviously increase the hydrophilicity of copolymer. The falling ball viscosity of AN/IA system is lower when compared with the other three systems, but when under the low concentration of monomer, AN/MA system has the highest viscosity. Electron paramagnetic resonance (EPR) indicates that the peak width change for the different copolymer be mainly caused by the spin-spin interaction. The copolymer of AN/AM has the lowest starting-exothermal reaction temperature and AM can alleviate the exothermic reaction and moderate the stabilization exotherm

With the development of computer technology and calculation methods, the finite element method to analyze wheel/rail rolling contact became popular. For the increasing requirement of calculation scale and computing accuracy, the parallel computing method and parallel computing environment become an effective way to solve this problem. The parallel computing methods of contact problem is analyzed firstly. Then, the contact algorithm and parallel computing of ABAQUS is introduced. And the parallel computing environment using MPI in ABAQUS is put forward. On the basis of cluster, some different finite element model is solved by implicit and explicit solution. It is found that the mesh size of wheel/rail contact field is refined to 0.75mm in order to ensure accuracy for engineering. At last, the parallel computing for the contact problem of wheel/rail is discussed using the speedup and efficiency.