Evolution of microstructure of aluminum alloy hollow shaft in cross wedge rolling without mandrel

During the process of cross wedge rolling of aluminum alloy hollow shaft, the evolution of its microstructure has an important influence on the mechanical properties of the rolled piece. In order to obtain the microstructure evolution law of aluminum alloy hollow shaft in cross wedge rolling without mandrel, a finite element model is constructed through the finite element software Deform-3D. The influences of rolling temperature, sectional shrinkage,spreading angle and forming angle on the average grain size of rolled piece are studied by numerical simulation of microstructure evolution. The cellular automata method reveals the inherent relationship between the process parameters and the evolution of the microstructure, and provides a reference for optimizing the rolling process parameters of aluminum alloy hollow shafts and improving the forming quality. The results show that the average grain size of the rolled piece increases with the increase of the rolling temperature, decreases with the increase of the sectional shrinkage,and decreases first and then increases with the increase of the spreading angle, and changes little with the increase of the forming angle.

茶园绿盲蝽综合治理技术

综述了绿盲蝽(Apolygus lucorμm)发生规律及防治相关研究。概述了绿盲蝽的形态特征、危害症状及发生规律,总结了茶园绿盲蝽的防治方法,包括农业防治、物理防治、化学防治、生物防治等,并展望了今后茶园绿盲蝽的研究方向。

鄂茶1号工夫红茶适制性研究

以鄂茶1号茶鲜叶为原料,按照工夫红茶初制工艺,通过检测主要生化成分和挥发性化合物结合感官评审,研究鄂茶1号茶鲜叶红茶的适制性。结果表明,由鄂茶1号制作的红茶的水浸出物、茶多酚、氨基酸和可溶性糖含量分别为47.3%、16.2%、3.2%和3.3%,茶黄素、茶红素和茶褐素含量分别为0.6%、6.1%和7.2%;共鉴定出51种挥发性化合物,其中气味活度值(Odor activity values,OAVs)大于1的香气成分有11种,包括β-紫罗酮、β-大马烯酮、芳樟醇及其氧化产物(2种)、香叶醇、癸醛、壬醛、苯乙醛、辛醛、柠檬烯;滋味醇厚,花果香浓郁,适制高档红茶。