Plasma electrolytic oxidation （PEO） is carried out on 6061 Al-alloys in a weak alkaline electrolyte containing NaOH, Na2SiO3 and NaCl. Centered on the correlation of composition and structure, analyses by means of X...Plasma electrolytic oxidation （PEO） is carried out on 6061 Al-alloys in a weak alkaline electrolyte containing NaOH, Na2SiO3 and NaCl. Centered on the correlation of composition and structure, analyses by means of X-ray diffration （XRD）, scanning electron microscope （SEM） and energy dispersive spectrometry （EDS） are conducted on the specimens, which have been PEO-treated under hybrid voltages of different direct current （DC） values （140-280 V） with constant alternate current （AC） amplitude （200 V）. Attention is paid to the composition, properties and growth mechanism of oxide layers formed with hybrid voltages. Moreover, the main effects of DC value are discussed. Ceramic layers with a double-layer structure which combines hard outer and soft inner layers are found to be consist of α-Al2O3,γ-Al2O3 and mullite. With the DC values increasing, the growth of the ceramic layers tends to have increasingly obvious three-stage feature.展开更多
1 Introduction The engineering and construction(E&C)industry is human resource-intensive.Most E&C tasks are performed,handled,or supervised by humans.Besides,the size and complexity of todays E&C projects ...1 Introduction The engineering and construction(E&C)industry is human resource-intensive.Most E&C tasks are performed,handled,or supervised by humans.Besides,the size and complexity of todays E&C projects require the involvement of many professionals,often from different organizations,working together(Ballesteros-Perez et al.,2019).Further,the E&C industry is not only human resourceintensive but also leader-driven.The most vital resource of an E&C firm is its executive leadership(Perrenoud and Sullivan,2017).Of course,leadership is multifaceted and must be defined and bounded within the context of the topic of interest(Schell et al.,2018)-highly successful executive-level engineers leading project-based E&C organizations.展开更多
基金Changwon National University in 2008 and National IT Industry Program Agency(NIPA-2009-C-C1090-0903-0007)
文摘Plasma electrolytic oxidation （PEO） is carried out on 6061 Al-alloys in a weak alkaline electrolyte containing NaOH, Na2SiO3 and NaCl. Centered on the correlation of composition and structure, analyses by means of X-ray diffration （XRD）, scanning electron microscope （SEM） and energy dispersive spectrometry （EDS） are conducted on the specimens, which have been PEO-treated under hybrid voltages of different direct current （DC） values （140-280 V） with constant alternate current （AC） amplitude （200 V）. Attention is paid to the composition, properties and growth mechanism of oxide layers formed with hybrid voltages. Moreover, the main effects of DC value are discussed. Ceramic layers with a double-layer structure which combines hard outer and soft inner layers are found to be consist of α-Al2O3,γ-Al2O3 and mullite. With the DC values increasing, the growth of the ceramic layers tends to have increasingly obvious three-stage feature.
文摘1 Introduction The engineering and construction(E&C)industry is human resource-intensive.Most E&C tasks are performed,handled,or supervised by humans.Besides,the size and complexity of todays E&C projects require the involvement of many professionals,often from different organizations,working together(Ballesteros-Perez et al.,2019).Further,the E&C industry is not only human resourceintensive but also leader-driven.The most vital resource of an E&C firm is its executive leadership(Perrenoud and Sullivan,2017).Of course,leadership is multifaceted and must be defined and bounded within the context of the topic of interest(Schell et al.,2018)-highly successful executive-level engineers leading project-based E&C organizations.
