RPW法在水泵厂装配线平衡上的应用

以某水泵厂的装配流水线为研究对象,对其装配流程和节拍进行测定与分析,根据6σ理论确定每道工序的标准时间,根据每道工序的标准时间和作业顺序图,运用RPW(分级位置权法)对其进行平衡,以几个评价指标对装配流水线平衡前后的状况进行评价,结果表明生产线总停顿时间减少,平衡率得到提高。     

装配生产线的平衡问题研究

讨论了装配过程中的生产平衡问题，介绍了最大候选原则和分级位置权(RPW)法2种装配线平衡的人工方法，结合实例介绍了2种方法在装配线平衡问题上的应用，并对比分析了2种不同方法分配装配作业的装配线效率。     

HR4 Gene Is Induced in the Arabidopsis-Trichoderma atroviride Beneficial Interaction

Plants are constantly exposed to microbes, for this reason they have evolved sophisticated strategies to perceive and identify biotic interactions. Thus, plants have large collections of so-called resistance (R) proteins that recognize specific microbe factors as signals of invasion. One of these proteins is codified by the Arabidopsis thaliana HR4 gene in the Col-0 ecotype that is homologous to RPW8 genes present in the Ms-0 ecotype. In this study, we investigated the expression patterns of the HR4 gene in Arabidopsis seedlings interacting with the beneficial fungus Trichoderma atroviride. We observed the induction of the HR4 gene mainly at 96 hpi when the fungus interaction was established. Furthermore, we found that the HR4 gene was differentially regulated in interactions with the beneficial bacterium Pseudomonas fluorescens and the pathogenic bacterium P. syringae. When hormone treatments were applied to A. thaliana (Col-0), each hormone treatment induced changes in HR4 gene expression. On the other hand, the expression of the RPW8.1 and RPW8.2 genes of Arabidopsis ecotype Ms-0 in interaction with T. atroviride was assessed. Interestingly, these genes are interaction-responsive; in particular, the RPW8.1 gene shows a very high level of expression in the later stages of interaction. These results indicate that HR4 and RPW8 genes could play a role in the establishment of Arabidopsis interactions with beneficial microbes.     

反复塑性变形对SiC_p/AZ31镁基复合材料组织和性能的影响

采用反复塑性变形(RPW)技术,结合挤压工艺制备出SiC颗粒增强AZ31镁基复合材料,研究了循环次数(RPW次数)对SiC_p/AZ31镁基复合材料显微组织和性能的影响.结果表明,反复塑性变形具有明显的AZ31基体晶粒细化、SiC_p细化和分散作用,能显著提高SiC_p/AZ31复合材料的抗拉强度和硬度,并改善其塑性.在SiC_p的体积分数为4%时,经RPW为300次的热挤压后,AZ31基体晶粒粒径达到最小值20 μm,SiC_p被粉碎成3 μm以下的微粒,且弥散分布于合金基体中,复合材料的室温抗拉强度和硬度(HV)达到或接近最大值,分别为359 MPa和107.     

Effect of applied current on the formation of defect in PWR nuclear fuel rods in resistance pressure welding process

The welding of zirconium alloy components is one of the most critical processes in the fabrication of nuclear fuel rods used in pressurized water reactors. For this, various welding processes, such as gas tungsten arc welding, electron beam welding, laser beam welding, and resistance pressure welding (RPW), are used around the world. In Korea, the RPW process is being used to fabricate nuclear fuel assembly fuel rods. This study investigated changes in the weldment shape owing to welding conditions such as welding current, welding force, and overlapping. The welding soundness of the weldment was evaluated by hydraulic burst test. The welding temperature of the weld zone was measured using a thermal infrared method. Discontinuous black spots in the weld line, regarded as a non-bonding defect, were confirmed as spots caused by the carbide precipitation of zirconium during welding.