The effects of microwave sintering on the sintering behaviour, microstructure and dielectric properties of Bi2O3-doped (Ba0.6Sr0.4)(Ti0.94Cu0.06)O3 (BSTC) ceramics were investigated. The microstructure and dielectric ...The effects of microwave sintering on the sintering behaviour, microstructure and dielectric properties of Bi2O3-doped (Ba0.6Sr0.4)(Ti0.94Cu0.06)O3 (BSTC) ceramics were investigated. The microstructure and dielectric properties of a BSTC ceramic were also studied given different amounts of Bi2O3 doping. Microwave heating with sintering temperatures below 1000°C significantly improves the densification of Bi2O3-doped BSTC ceramics. The BSTC ceramic with 1 wt% Bi2O3 addition sintered at 950°C in air for 30 min exhibited dielectric properties of er = 3756, dielectric loss of tanδ = 7 × 10-3 and bulk density > 96% of theoretical density.展开更多
The multi-roller straightening process of section steel is analyzed by the springback theory of small curva- ture plane bending. The theoretical analysis results prove the curvature unification in straightening proces...The multi-roller straightening process of section steel is analyzed by the springback theory of small curva- ture plane bending. The theoretical analysis results prove the curvature unification in straightening process and clear- ly reveal the principle of the multi-roller straightening process. The principle can be described as~ the initial curva- tures are reduced by several times anti-bendingl meanwhile the initial curvature differences are diminished and the residual curvatures are unified~ finally, the member after curvature unification is straightened by the last anti-ben- ding. With the plastic region ratios becoming larger, the initial curvatures are more easily unified in straightening process. Based on the plastic region ratios and the required number of roller systems for unifying the initial curva- tures, the large deformation straightening strategy and the small deformation straightening strategy are redefined. The new definition provides an important theoretical basis for setting reliable reduction rules. Through the theoretical analysis results, a new straightener design philosophy is proposed to improve the straightening quality and further increase the adjustment precision as well as the flexibility of the last roller system. The adjustable end roller emerges as the times required, achieving a good effect in practical application.展开更多
文摘The effects of microwave sintering on the sintering behaviour, microstructure and dielectric properties of Bi2O3-doped (Ba0.6Sr0.4)(Ti0.94Cu0.06)O3 (BSTC) ceramics were investigated. The microstructure and dielectric properties of a BSTC ceramic were also studied given different amounts of Bi2O3 doping. Microwave heating with sintering temperatures below 1000°C significantly improves the densification of Bi2O3-doped BSTC ceramics. The BSTC ceramic with 1 wt% Bi2O3 addition sintered at 950°C in air for 30 min exhibited dielectric properties of er = 3756, dielectric loss of tanδ = 7 × 10-3 and bulk density > 96% of theoretical density.
基金Item Sponsored by National Natural Science Foundation of China(51178452)
文摘The multi-roller straightening process of section steel is analyzed by the springback theory of small curva- ture plane bending. The theoretical analysis results prove the curvature unification in straightening process and clear- ly reveal the principle of the multi-roller straightening process. The principle can be described as~ the initial curva- tures are reduced by several times anti-bendingl meanwhile the initial curvature differences are diminished and the residual curvatures are unified~ finally, the member after curvature unification is straightened by the last anti-ben- ding. With the plastic region ratios becoming larger, the initial curvatures are more easily unified in straightening process. Based on the plastic region ratios and the required number of roller systems for unifying the initial curva- tures, the large deformation straightening strategy and the small deformation straightening strategy are redefined. The new definition provides an important theoretical basis for setting reliable reduction rules. Through the theoretical analysis results, a new straightener design philosophy is proposed to improve the straightening quality and further increase the adjustment precision as well as the flexibility of the last roller system. The adjustable end roller emerges as the times required, achieving a good effect in practical application.
