Applied Mechanics and Materials Vol. 464

Abstract: A novel method to functionalize graphene oxide (GO) by hyperbranched polysiloxane via polyhydrosilylation is reported, taking advantage of hyperbranched polysiloxane that possesses good properties such as low viscosity, good rheology, good solubility and high reactivity. The changes in GO surface morphology, chemistry and physical conditions at different stages are characterized by Fourier-transform infrared spectra (FT-IR), X-ray photoelectron spectroscopy (XPS) and Transmission electron microscopy (TEM). XPS analysis shows that the oxygen content of GO is 29.90% and the silicon content of hyperbranched polysiloxane grafted graphene oxide (HBPGO) is 18.66%. The results indicate that hyperbranched polysiloxane is successfully grafted onto the surface of GO and this novel nanostructure may have potential applications in composites.

Abstract: Fluorinated polyurethanes (FPU) was prepared using fluorinated polyether polyol (FPO) as the soft segment, 4,4`-diphenylmethane diisocyanate (MDI) as the hard segment, 1,4-butanodiol (BDO) as the chain extender and catalysts. Tin metal catalysts were used to catalyze the polyurethane reaction of polyether polyols and isocyanate. The effect of different catalysts including stannous octoate (T-9) and dibutyltindalautrate (DBTDL) on the structure, surface properties and thermal properties of FPU was studied. The structural elucidation of the synthesized FPU was performed by Fourier transform infrared (FT-IR) and discovered that with decreasing catalyst efficiency or without catalyst, the strength of hydrogen bounds were enhanced. The FPU films surface was characterized by contact angle (CA) and atomic force microscopy (AFM) and it was found that the phase separation was increasing with increasing catalyst efficiency. The thermal property was exhibited by Thermo gravimetric (TG) and showed that joining catalyst improved stability significantly.

Abstract: The absorbing performance have been tested and analyzed by taking cement as matrix, blending material silica fume and culver zed fuel ash for absorbing agent trial Sample, in the 8 ~ 18 GHz frequency band, the results indicate that silica fume and culver zed fly ash and composite cement which made of Absorbing material has good absorbing property. Blending material absorbing properties of cement-based materials, the impact must be considered together, not the more the better, when blending material exceeding a certain threshold, its ability of wave-transparent enhance while absorbing property will be reduced Finally. By using ANSYS software for computer simulation of the specimen to test experimental data and found the computer simulation algorithm not only can verify the correctness of the conclusion but also auxiliary correction deviation appeared in the course of the real data and the error value.

Abstract: The absorbing performance have been tested and analyzed by taking cement as matrix, blending material graphite and carbon fibers for absorbing agent trial Sample, in the 8 ~ 18 GHz frequency band, the results indicate that graphite and carbon fibers and composite cement which made of absorbing material has good absorbing property. Blending material absorbing properties of cement-based materials, the impact must be considered together, not the more the better, when blending material exceeding a certain threshold, enhance its ability of wave-transparent enhance while absorbing property will be reduced finally. By using ANSYS software for computer simulation of the specimen to test experimental data and found the computer simulation algorithm not only can verify the correctness of the conclusion but also auxiliary correction deviation appeared in the course of the real data and the error value.

Abstract: The paper refers to utilization of low temperature plasma discharge in air on polypropylene fibres. Such fibres have been tested in concrete as reinforcement. The effect has been tested by restrain ring test. The experiment proved positive correlation between time of exposure and cracks suppression. The effect is considered as improved cohesion of polymer fibres with cement matrix.

Abstract: Isoconcentration flooding systems were prepared, their viscosity, shearing resistance, viscoelasticity, stability and molecule clew size were measured and the impact of polymer-bearing wastewater on polymer performance was determined in order to study the impact of polymer systems prepared with polymer-bearing wastewater on polymer performance in the polymer flooding process of Daqing oilfield. The result indicates: at the same preparation concentration, the storage modulus, loss modulus, viscosity stability, molecule clew size and shearing resistance of polymer solution systems are increased with increase in the polymer concentration in wastewater, the properties of a fresh water system are better than those of a wastewater system, the properties of a physicochemical wastewater system are better than those of a biochemical wastewater system, and the residual polymers in sewage have good viscosity increasing capacity. Therefore, polymer-bearing wastewater improves the properties of polymer systems to a certain degree and can be used as water for polymer system preparation.

Abstract: Objective.To investigates the effects of sufentanil post conditioning on Myocardial ischemia reperfusion injury in rats in vivo. Methods. To randomly divide 40 male SD rats equally into 4 groups, including Sham group, ischemia-reperfusion group (Group I/R ), ischemic post conditioning group (Group IPO) and sufentanil post conditioning group (Group SUF). The left anterior descending coronary arterys (LAD) of rats in 4 groups are ligated for 30 minutes and are re-perfused for 120 mins. To measure the myocardial infarction size (IS/AAR%) with double-staining with Even's blue and triphenyltetrazolium chloride, to calculate the concentration of cTnI, and to observe the HE staining and the expression of Bcl-2 and Bax. Result. Comparing with Group 1/R, the myocardial infarction size (IS/AAR%), and the concentration of cTnI in Group IPO and SUF all reduced significantly. Comparing with Group 1/R, cell morphological observation shows less change in pathology. And the expression of Bcl-2 increases and expression of Bax decreases in Group IPO and SUF than that in Group 1/R. Conclusion. Sufentanil post conditioning has protective effects on myocardial ischemia-reperfusion injury in rats in vivo.

Abstract: The method of liquid phase oxidation was adopted to prepare grafted carbon black (GCB). The structures of GCB were investigated with FT-IR. The particle size and polydispersity of GCB were researched by nanoparticle size analyzer. The dispersion stability of GCB was determined by the visible light spectrophotometer. The results showed that the graft modification was an effective method for improving the dispersion stability of carbon black (CB) in both polar and non-polar solution.

Abstract: GeO₂ has been doped solely and together with SiO₂ into barium titanate ceramics by mixing and calcination. The microstructure and dielectric properties of doped BaTiO₃ have been characterized. When doped in BaTiO₃, Ge⁴⁺ ion could incorporated into the crystal lattice of BaTiO₃ to occupied Ti⁴⁺ sites. For relative smaller Ge⁴⁺ ion, the tetragonal phase could be enhanced. As dielectric properties have strong relation to tetragonal phase. The relative permittivity could be increased in this mechanism. However, the high leakage current which induced by more ionic defect was also lead to high dielectric loss. Besides, the assemble in grain boundary by Ge⁴⁺ ion may also have effect. Results on the GeO₂-SiO₂ co-doped sample showed that the mechanisms of Ge doping and Si doing could happen at one time.