No abstract

ZrB2-SiC ceramic composites was brazed by using Ti-Zr-Ni-Cu active filler in a vacuum furnace. The microstructure and interfacial phenomena of the joints were analyzed by means of SEM, EDS and XRD. The joining effect was evaluated by shear strength. The results showed that the reaction products of the ZrB2-SiC ceramic composites joint brazed with Ti-Zr-Ni-Cu active filler were TiC, ZrC, Ti5Si3, Zr2Si, Zr(s,s) and (Ti, Zr)2 (Ni, Cu). The maximum shear strength of the ZrB2-based ultra-high-temperature ceramic composites brazed joints is 143.5 Subscript textMPa at brazing temperature T=920°C and holding time t=10min.

A series of oil in water (O/W) microemulsions were prepared through drop by drop method at constant temperature, taking Span80/Tween80 as a composite emulsifying system and Macol-52 as oil phase. Effects of the mass ratio of composite emulsifying system and oil/emulsifier ratio on the particle size were studied. Finally, the best technological conditions were selected and the stability of the microemulsion was also researched. Results showed that the most suitable Span80/Tween80 mass ratio was 1:1 and the oil/emulsifier ratio is 1:1. Under this condition, the mean particle size of the o/w microemulsion was 71.1 nm and the polydispersity index was 0.151. Moreover, the microemulsion maintain a bright and uniform stable system after 20minutes’ centrifugation at the speed of 4000r/min and the particle size increased slightly.

Combining the scientific research project- the study on cable-stayed suspension bridges, with the engineering background of Dalian Gulf Bridge to be built, this paper focuses on the seismic effect of non-linear viscous dampers on Self-anchored Cable-stayed Suspension Bridge. Based on the non-linear dynamic time-history analysis, the parameter sensitivity of damping coefficient and velocity exponent is analyzed. Through the analysis results, the proper dampers are decided. The seismic response result of before setting dampers is compared with that of after setting dampers. The results show that viscous dampers not only can greatly reduce the relative displacement and inner force under seismic effect of key positions of Self-anchored Cable-stayed Suspension Bridge, but can efficiently minimize the damage caused by earthquakes on bridge structure without changing static force behavior, which can provide evidence of seismic design for similar bridges.