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Engineering

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Selected Works

2014

Mgb2

Articles 1 - 5 of 5

Full-Text Articles in Physical Sciences and Mathematics

Power-Law Relationship Between Critical Current Density, Microstructure, And The N-Value In Mgb2 Superconductor Wires, Ashkan Motaman, Shaon Barua, Dipak Patel, Minoru Maeda, Kookchae Cheong, Jung Ho Kim, S X. Dou, Md Shahriar Al Hossain Oct 2014

Power-Law Relationship Between Critical Current Density, Microstructure, And The N-Value In Mgb2 Superconductor Wires, Ashkan Motaman, Shaon Barua, Dipak Patel, Minoru Maeda, Kookchae Cheong, Jung Ho Kim, S X. Dou, Md Shahriar Al Hossain

Shi Xue Dou

Dissipation-free MgB2 superconducting wires are valuable in terms of practical applications. Herein, we have found a strong correlation between critical current density (J c ) and the n-value extracted from the electric field versus current density characteristic. The power-law relationship (m) between the J c and the n-value, n∝Jmc , represents a critical index which is strongly dependent on operating temperatures.


Enhancing Superconducting Properties Of Mgb2 Pellets By Addition Of Amorphous Magnetic Ni-Co-B Nanoparticles, Mislav Mustapic, Josip Horvat, Md Shahriar Hossain, Zeljko Skoko, S X. Dou Apr 2014

Enhancing Superconducting Properties Of Mgb2 Pellets By Addition Of Amorphous Magnetic Ni-Co-B Nanoparticles, Mislav Mustapic, Josip Horvat, Md Shahriar Hossain, Zeljko Skoko, S X. Dou

Josip Horvat

Amorphous magnetic Ni-Co-B nanoparticles with an average size of 5 nm were added to precursor powders of MgB2 superconductor. The preparation procedure for MgB2 pellets was optimized for obtaining the best critical current density (Jc) at elevated magnetic fields. Addition of Ni-Co-B decreases the Jc for heat treatment of precursor powders at 650 ° C. Heat treatments at 770 ° C and higher improve Jc at 20 and 5 K. This improvement occurs at both temperatures through the increase of the effective connectivity between MgB2 crystals. Vortex pinning was enhanced at 5 K, but not at 20 K. Ni-Co-B nanoparticles …


Enhancing Superconducting Properties Of Mgb2 Pellets By Addition Of Amorphous Magnetic Ni-Co-B Nanoparticles, Mislav Mustapic, Josip Horvat, Md Shahriar Hossain, Zeljko Skoko, S X. Dou Mar 2014

Enhancing Superconducting Properties Of Mgb2 Pellets By Addition Of Amorphous Magnetic Ni-Co-B Nanoparticles, Mislav Mustapic, Josip Horvat, Md Shahriar Hossain, Zeljko Skoko, S X. Dou

Shi Xue Dou

Amorphous magnetic Ni-Co-B nanoparticles with an average size of 5 nm were added to precursor powders of MgB2 superconductor. The preparation procedure for MgB2 pellets was optimized for obtaining the best critical current density (Jc) at elevated magnetic fields. Addition of Ni-Co-B decreases the Jc for heat treatment of precursor powders at 650 ° C. Heat treatments at 770 ° C and higher improve Jc at 20 and 5 K. This improvement occurs at both temperatures through the increase of the effective connectivity between MgB2 crystals. Vortex pinning was enhanced at 5 K, but not at 20 K. Ni-Co-B nanoparticles …


Synergetic Combination Of Limd With Chpd For The Production Of Economical And High Performance Mgb2 Wires, Minoru Maeda, Md Shahriar Ai Hossain, Ashkan Motaman, Jung Ho Kim, Anna Kario, Matt Rindfleisch, Mike Tomsic, S X. Dou Mar 2014

Synergetic Combination Of Limd With Chpd For The Production Of Economical And High Performance Mgb2 Wires, Minoru Maeda, Md Shahriar Ai Hossain, Ashkan Motaman, Jung Ho Kim, Anna Kario, Matt Rindfleisch, Mike Tomsic, S X. Dou

Shi Xue Dou

We propose an economical fabrication concept, the localized internal magnesium diffusion (IMD) method. Instead of using a single magnesium (Mg) rod in the center of a metal sheath tube, we use large-sized Mg particles (20-50 mesh) mixed well with cheap 97% crystalline boron powder to fill the metal sheath tube. After a repeated drawing process, the coarse Mg is elongated along the core wire axis of the metal sheath tube. Textured MgB2 grains are then formed during the sintering process. In the localized IMD process, however, there is still a need to improve the overall density. In order to increase …


Reaction Method Control Of Impurity Scattering In C-Doped Mgb2: Proving The Role Of Defects Besides C Substitution Level, S K. Chen, K Y. Tan, A S. Halim, X Xu, K S. B De Silva, W K. Yeoh, S X. Dou, A Kursumovic, J L. Macmanus-Driscoll Mar 2014

Reaction Method Control Of Impurity Scattering In C-Doped Mgb2: Proving The Role Of Defects Besides C Substitution Level, S K. Chen, K Y. Tan, A S. Halim, X Xu, K S. B De Silva, W K. Yeoh, S X. Dou, A Kursumovic, J L. Macmanus-Driscoll

Shi Xue Dou

In this study, Si and C were incorporated into polycrystalline MgB2 via in situ reaction of Mg and B with either SiC or with separate Si and C (Si+C). The electrical transport and magnetic properties of the two series of samples were compared. The corrected resistivity at 40K, pA(40K), is higher for the SiC reacted samples regardless of carbon (C) substitution level, indicating larger intragrain scattering because of the simultaneous reaction between Mg and SiC and carbon substitution during the formation of MgB2. In addition, because of the cleaner reaction route for the SiC reacted samples, the calculated active area …