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The Synthesis Of Lamellar Nano Mgb2 Grains With Nanoimpurities, Flux Pinning Centers And Their Significantly Improved Critical Current Density, Zongqing Ma, Yongchang Liu, Qi Cai
The Synthesis Of Lamellar Nano Mgb2 Grains With Nanoimpurities, Flux Pinning Centers And Their Significantly Improved Critical Current Density, Zongqing Ma, Yongchang Liu, Qi Cai
Australian Institute for Innovative Materials - Papers
MgB2 superconductors with unique microstructures were rapidly fabricated at low temperatures, and exhibited significantly improved critical current density (Jc). According to the microstructure observations, the prepared samples consisted of lamellar nano MgB2 grains with many embedded nanoimpurities (about 10 nm). The formation of these lamellar nano MgB2 grains is associated with the presence of a local Mg-Cu liquid at sintering temperatures as low as 575°C. The ball milling treatment of the original powders also plays a positive role in the growth of lamellar grains. Based on an analysis of the relationship between resistivity and temperature, the lamellar nano MgB2 grains …
Microscopic Role Of Carbon On Mgb2 Wire For Critical Current Density Comparable To Nbti, Jung Ho Kim, Sangjun Oh, Yoon-Uk Heo, Satoshi Hata, Hiroaki Kumakura, Akiyoshi Matsumoto, Masatoshi Mitsuhara, Seyong Choi, Yusuke Shimada, Minoru Maeda, Judith Macmanus-Driscoll, S X. Dou
Microscopic Role Of Carbon On Mgb2 Wire For Critical Current Density Comparable To Nbti, Jung Ho Kim, Sangjun Oh, Yoon-Uk Heo, Satoshi Hata, Hiroaki Kumakura, Akiyoshi Matsumoto, Masatoshi Mitsuhara, Seyong Choi, Yusuke Shimada, Minoru Maeda, Judith Macmanus-Driscoll, S X. Dou
Australian Institute for Innovative Materials - Papers
Increasing dissipation-free supercurrent has been the primary issue for practical application of superconducting wires. For magnesium diboride, MgB2, carbon is known to be the most effective dopant to enhance high-field properties. However, the critical role of carbon remains elusive, and also low-field critical current density has not been improved. Here, we have undertaken malic acid doping of MgB2 and find that the microscopic origin for the enhancement of high-field properties is due to boron vacancies and associated stacking faults, as observed by high-resolution transmission electron microscopy and electron energy loss spectroscopy. The carbon from the malic acid almost uniformly encapsulates …
Methane Activation On Fe4 Cluster: A Density Functional Theory Study, Qiao Sun, Zhen Li, Meng Wang, Aijun Du, Sean C. Smith
Methane Activation On Fe4 Cluster: A Density Functional Theory Study, Qiao Sun, Zhen Li, Meng Wang, Aijun Du, Sean C. Smith
Australian Institute for Innovative Materials - Papers
We report a comprehensive theoretical study on reaction of methane by Fe4 cluster. This Letter gains insight into the mechanism of the reaction and indicate the Fe4 cluster has strong catalytic effect on the activation reaction of methane. In detail, the results show the cleavage of the first C-H bond is both an energetically and kinetically favourable process and the breaking of the second C-H is the rate-determining step. Moreover, our Letter demonstrates that the different cluster size of iron can not only determine the catalytic activity of methane but also control the product selectivity.