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双丝MAG(熔化极活性气体保护焊)焊接的应用越来越广泛.在造船行业中,由于船台焊接作业特点决定了电焊机设备普遍使用几十米的加长控制电缆.利用嵌入式系统,研究焊接电源和送丝机之间控制信号通信系统,实现减少控制电缆的芯数,既可减少生产成本,又可减少断线故障率,提高生产质量和效率、节能降耗,具有重要的现实意义,且对于多丝焊接... 相似文献
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以Ar CO2作为保护气体,研究实芯焊丝MAG焊的混合气体配比、焊接电流、电弧电压和气体流量对熔敷速度、熔敷系数和熔敷效率的影响,结果表明,Ar气比例越大,熔敷效率越高,Ar气比例达到80%以上,熔敷效率显著增加,说明适当的焊接工艺可获得较高的熔敷速度、熔敷系数和熔敷效率。 相似文献
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Accessibility is a key concept in transportation research and an important indicator of people’s quality of life. With the development of big data analytics, dynamic accessibility that captures the temporal variations of accessibility becomes an important research focus. Few prior studies focus on comparative measures of dynamic accessibility to Points of Interest (POIs) by alternative travel modes. To fill this research gap, we propose a new index called dynamic modal accessibility gap (DMAG), which draws upon available data on residents’ real travel routes using different travel modes, as well as the data on POIs. We study the DMAG in the real-travel covered area, assuming POIs are only useful if it is within someone’s real-travel covered area. We then apply this DMAG methodology to Shanghai’s central city and peripheral area. In both cases, we measure the accessibility for public and private travel modes. As an example, one-week taxi GPS and metro smart card data, and POIs data are used to generate the DMAG index for 30-minute and 60-minute trip durations for weekdays and holidays. Results show that DMAG can reflect the pattern of temporal variations. The proposed DMAG analytical framework, which can be applied at both the user and the system levels, can support urban and transportation planning, and promote social equity and livability. 相似文献
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