共查询到13条相似文献,搜索用时 62 毫秒
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李胜乐 《精密制造与自动化》2013,(4):40-41,45
介绍了SINUMERIK 802D sl在数控坐标磨床中的应用,叙述了数控坐标磨床的硬件结构。通过对系统参数的调整和设定,对系统程序的编制及实际调试,解决了各轴的实际位置反馈、气动轴回参考点和Z轴往复行程设置难点问题,扩大了坐标磨床的功能。该系统投入运行半年多来运行良好,提高了生产效率。 相似文献
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卢云峰 《精密制造与自动化》2013,(4):46-47,52
介绍了SINUMERIK 802D sl数控系统在外圆磨床中的应用,在西门子公司近年来推出的数字化数控系统中配置了一块PP72/48模板,可以实现72点输入和48点输出的可编程序控制器(PLC)控制。通过其中2个单轴功率驱动模块驱动2个线性轴和1个模拟主轴,在伺服电动机中内置了速度反馈和位移反馈传感器,和主机一起形成一个半闭环控制系统。实践结果表明,磨床采用西门子802D sl数控系统可显著提高磨床的控制精度,并且价格适中,具有很高的性价比。 相似文献
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双曲线编程在SIEMENS 802D数控系统中的应用 总被引:1,自引:0,他引:1
尤东升 《机械制造与自动化》2007,36(4):88-91
数控编程是目前CAD/CAPP/CAM系统中最能明显发挥效益的环节之一,它在实现设计加工自动化、提高加工精度和加工品质、缩短产品研制周期等方面发挥着重要作用.数控编程是从零件图样到获得数控加工程序的全过程.由于生产实际的强烈需求,国内外都对数控编程技术进行了广泛的研究,并取得了丰硕成果. 相似文献
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为实现硬质合金圆盘锯床系统的精确控制和自动运行,分析了生产工艺特点,建立了锯床机械主体结构,采用了SINUMERIK802D sl数控系统和S7-300PLC相结合,通过Profibus总线进行系统集成,完成了系统的硬件配置和软件设计.实践结果证明,该控制系统控制精确、运行稳定、自动化程度高. 相似文献
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西门子802D sl在磨床上的应用 总被引:1,自引:0,他引:1
描述西门子802D sl(G/N)磨床版关于磨床功能的应用,诸如摆动功能,单程序段多进给速度,快速输入输出功能,NC/PLC数据交换等功能. 相似文献
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FEI CHENG YIQIAN DING QING XU WEI ZHANG YULAN ZHEN JING LIU SHICHENG LI CHANG TU GUOHUA LAI JUN LAN JINGFU CHEN 《Biocell》2022,46(4):1053-1066
Previous reports have suggested that Ang-(1-7) may have a protective effect in endothelial cells against highglucose (HG)-induced cell injury thanks to a modulatory mechanism in the NF-κB signaling pathway. In this study,we have examined whether NF-κB-IL-1β and Heme oxygenase-1 (HO-1) pathways contribute to the protection ofAng-(1-7) against hyperglycemia-induced inflammation and oxidative stress in human umbilical vein endothelial cells(HUVECs). Our results indicate that time-varying exposures of HUVECs, from 1 h to 24 h, to high glucoseconcentrations result in an increased expression of phosphorylated (p)-p65 and HO-1 in a time-dependent manner.As an inhibitor of NF-κB, pyrrolidinedithiocarbamic acid (PDTC) suppressed IL-1β production induced by HG. Ofnote, HUVECs previously treated with Ang-(1-7) (2 μM) for 30 min before being exposed to HG concentrationssignificantly ameliorated the HG-increased in p-p65 and IL-1β expression; whereas obviously up-regulated the level ofHO-1, along with inhibition of oxidative stress, inflammation, and the HG-induced cytotoxicity. Importantly, whenHUVECs were previously treated either with PDTC or IL-1Ra for 30 min before being exposed to HG, it significantlyprevented damages caused by high glucose concentrations mentioned above, while the treatment of HO-1 inhibitorSn-protoporphyrin (SnPP) before exposure to both HG and Ang-(1-7) significantly blocked the protective effectexerted by Ang-(1-7) on endothelial cells against injuries induced by HG mentioned above. To conclude, the data ofthis study showed that activation and inhibition of the NF-κB-IL-1β pathway and HO-1 pathway may constitute animportant defense mechanism against endothelial cell damage caused by HG concentrations. We additionally gavenew evidence showing that exogenous Ang-(1-7) exerts a protective effect on HUVECs against the HG-induced cellinjury via the inhibition and the activation of the NF-κB-IL-1β pathway and the HO-1 pathway, respectively. 相似文献
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衬板用铸态Fe-24Mn-7Al-1C耐磨钢的应变硬化行为研究 总被引:1,自引:0,他引:1
对衬板用新型铸态轻质Fe-24Mn-7Al-1C耐磨钢进行准静态条件下不同变形量的压缩试验,分析应变硬化行为,揭示出该铸态耐磨钢的加工硬化机理。根据压缩应力-应变曲线和对数真应力-对数真应变曲线分析压缩变形特征;并利用光学显微镜、X射线衍射和透射电镜研究不同应变量的变形后的微观组织形貌。研究结果表明,试验钢在屈服阶段的加工硬化曲表现出双加工硬化指数行为;在透射电子显微镜和X射线衍射分析时既未发现形变诱发马氏体存在,也没有发现位错胞和形变孪晶,变形后仍为奥氏体单相组织;在不同变形量变形后的奥氏体显微组织中依次可以观察到位错堆积(1%)、高密度位错墙(5%)、泰勒晶格(10%)、具有高密度位错的畴界(20%)和微带(50%),说明轻质Fe-24Mn-7Al-C耐磨钢钢微观变形机理是平面滑移机制。 相似文献