Application of a modified rigid plastic model to the out-plane fracture of `easy open end cans'

Models, using simple energy balance, have been developed, by different authors, to describe the ductile materials behaviour in mode III shear fracture. The application of these models to the field of the opening of different types of can ends and mainly to the easy open ends (EOE) seems to be a powerful tool for design. In the present work, a simple experimental procedure, using scored testing pieces to reproduce similar conditions to those in the case of the EOE has been used. A model to describe the fracture process, under this condition has been developed, through the modification of the Mai and Cotterell rigid plastic model equations taking into account the bending elasticity and the strained nature of the steel at the score.     

西门子S7-300在易开盖后处理补涂装备上的应用

介绍了易开盖生产工艺中一种新的后处理工艺,即通过电泳补涂的方法来弥补易开盖在生产流程中形成的轻微擦伤,从而提高盖子耐蚀力,重点叙述了该装备中关键的PLC控制技术,通过采用西门子S7 - 300移位寄存的功能,实现了设备在线分选的控制,该项技术实施简单,在线控制准确、可靠、稳定,目前已掌握了电泳补涂的控制技术.     

On the nature of “easy paths” for the diffusion of oxygen in thermal oxide films on aluminum

Thermal oxide films grown on electropolished aluminum specimens have been investigated by transmission electron microscopy of stripped oxide films and ultramicrotomed sections. Particular attention has been focused on the nucleation sites -Al ₂ O ₃ crystals and the relationship of such sites to surface features on the electropolished aluminum surface. It is evident that easy paths for the diffusion of oxygen, or the nucleation sites of -Al ₂ O ₃ crystals, are not distributed randomly over the electropolished aluminum surface, but form preferentially in the amorphous oxide layer grown over preexisting metal ridges. Thus, the diffusion of molecular oxygen through cracks in the amorphous oxide layer represents the most realistic and acceptable basis for explaining the local growth of the -Al ₂ O ₃ crystals in thermal oxide films on aluminum, although the cracks have not yet been observed directly.Present address: Alcan International, Ltd., Banbury Laboratories, Banbury, Oxford, OX16 7SP, United Kingdom.     

绕出驱动链轮处刮板输送链张力计算

绕出驱动链轮处刮板输送链张力的计算与刮板输送链的强度计算有关。根据刮板输送链在驱动链轮上不跳齿及脱链流畅的要求。将无载分支的刮板输送链的中心线视为抛物线。近似计算并确定绕出驱动链轮处刮板输送链张力。并给出了算例及测量方法。为水平埋刮板输送机的设计及安装提供理论基础。     

纯弯曲正应力实验装置的改进

介绍材料力学中纯弯曲实验的简易加载设备,它具有结构简易,操作方便,地方小,节省经费等优点．从实验结果可以看出简易加载设备完全能满足材料力学的实验教学要求．     

顶空单滴液相微萃取与GC-MS联用测定易挥发溶剂

建立了采用顶空单滴液相微萃取与GC-MS联用检测易挥发溶剂的方法,并且优化了影响顶空单滴液相微萃取富集率的一些参数.最佳实验条件是：0.5μL十二烷作为萃取溶剂,样品温度为室温,萃取时间为10min.在最佳萃取条件下,检测限为0.000 1-1 mg/L;相关系数为0.904 8-0.988 7;线性范围为0.000 ...     

形状记忆织物的记忆性能研究

为探讨纯PTT、PTT与PET混纺、纯PET三类"形状记忆"织物以及免烫棉织物的形状记忆性能,对它们进行易塑形性能及折皱回复性能的测试,并对测试参数进行优化,研究了4种织物形状记忆性能的差异。结果表明:相较于半记忆、仿记忆织物以及免烫棉织物,纯PTT织物具有优异的形状记忆性能。     

山西国际贸易中心地下室顶板防水处理

介绍了单体建筑面积最大、智能化程度最高的山西国际贸易中心，其地下室顶板防水层的作业过程。由于对顶板防水功能的要求很高，经多方案比较，决定选用初凝时间长、终凝时间短、利于大面积作业的高分子益胶泥防水技术。阐述了高分子益胶泥的特点、技术性能、防水层施工准备及施工过程。其防水效果良好，经济效益高。     

Bi-Mn合金片状初生MnBi相在强磁场中的凝固组织

进行了强磁场下Bi-Mn合金的全熔和半固态实验,研究了MnBi相在强磁场中的凝固行为．在10T强磁场下从全熔态和Curie点以上半固态开始凝固的实验中,MnBi相在360℃左右逐渐形成片状相,其短轴为易磁化轴;加磁场后易磁化轴转向磁场方向,并沿磁场方向定向排列和聚合,最终形成条状组织;片状相在强磁场的作用下有分裂趋势．结合晶体的磁各向异性和生长各向异性的特点,从磁化理论和晶体学出发,分析了Bi—Mn合金初生MnBi相在磁场中的凝固行为．     

PA6／EHDPET共混纤维的形态结构

将聚酰胺６（ＰＡ６）与易水解性聚酯（ＥＨＤＰＥＴ）以体积比７／３的比例在工业规模的生产装置上进行熔体共混纺丝,再经拉伸→定型→卷曲→切断等切加工制得短纤维。用扫描电镜观察了共混纤维经碱水解及甲酸溶解后的形态结构,确认经碱水解处理后的纤维呈多孔中空藕状,而甲酸溶解后则呈超细纤维状,因此原共混纤维是以ＰＡ６为连续相,以ＥＨＤＰＥＴ为分散相的海－岛型复合纤维,并从流变学实验结果解释了该结构的成因。