MOF–derived porous carbon is a type of promising catalyst to replace expensive Pt–based catalysts for oxygen reduction reaction (ORR). The catalytic activity for ORR depends closely on pyrolysis conditions. In this work, a Co–doped ZIF–8 material was chosen as a research object. The effect of pyrolysis conditions (temperature, heating rate, two–step heating) on the ORR performance of ZIF–derived carbon catalysts was systematically studied. The Co–ZIF–8 catalyst carbonized at 900 °C exhibits better ORR catalytic activity than that carbonized at 800 °C and 1000 °C. Moreover, a low heating rate can enhance catalytic activity. Two–step pyrolysis is proven to be an effective way to improve the performance of catalysts. Reducing the heating rate in the low–temperature stage is more beneficial to the ORR performance, compared to the heating rate in the high–temperature stage. The results show that the Co–ZIF–8 catalyst exhibits the best performance when the precursor was heated to 350 °C at 2 °C/min, and then heated to 900 °C at 5 °C/min. The optimum Co–ZIF–8 catalyst shows a half–wave potential of 0.82 V and a current density of 5.2 mA·cm⁻² in 0.1 M KOH solution. It also exhibits high content of defects and good graphitization. TEM mapping shows that Co and N atoms are highly dispersed in the polyhedral carbon skeleton. However, two–step pyrolysis has no significant effect on the stability of the catalyst.

A TiN and TiN·Ti₂Cu reinforced copper matrix composite layer was cladded onto a T3 copper substrate to improve the anti-wear performance of copper products by means of the nitrogen-shielded gas tungsten arc cladding method (N₂-GTAC). Better than the traditional preparation method of TiN, the TiN particles in the cladding layer were in situ generated using N atoms of shielding gas and Ti atoms of pre-deposited metal powders. In addition, the composite phase TiN·Ti₂Cu occurred in the cladding layer, which also had a positive effect on anti-wearing. As Ti increased, the amount and grain size of TiN·Ti₂Cu and TiN increased as a result. The hardness of the cladding layer increased with the increasing amount of reinforced phase generated in the layer. The hardness of the layer reached a maximum of 410 HV, which is nearly 5.1 times greater than that of copper. The TiN·Ti₂Cu- and TiN-reinforced phases improved the wear resistance of the cladding layers. The cladding layer with 15 wt % Ti had the longsest launch stage (600 s) and the lowest fiction coefficient (0.56).

In this paper, the innovative teaching method of subject-Mechanical Engineering Material is put forward in order to fulfill the requirement of 'Outstanding Engineer Plans'. Through the application of Moocs, flipped classroom and project teaching method in teaching 'Mechanical Engineering Material', the learning and innovation capacity of the students will be improved tremendously. First, this new attempt of teaching method is aimed to the students who are born after 1990 and have distinctive personality compared with the 'after 70s' and 'after 80s'. Second, the knowledge points are rearranged and categorized and the logical relationship among these points are cleared in order to come up with the application of Moocs, flipped classroom and project teaching method. Finally, the application of Moocs, flipped classroom and project teaching method in teaching 'Mechanical Engineering Material' are designed and put into effort with the diverse teaching modes including pre-class online course, class discussion and case based teaching.

In this paper, the new attempts on instructing mode of 'mechanical engineering Materials are conducted in order to improve the students' enthusiasm of learning and encourage the teachers' positivity of teaching. And these new trials are included Moocs, VR technology and project instructing mode, which facilitate the students to master the main content of this curriculum dramatically and improve the teaching quality to a large extent.