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Physical Sciences and Mathematics

Selected Works

2013

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Articles 1 - 6 of 6

Full-Text Articles in Engineering

In-Field Jc Improvement By Oxygen-Free Pyrene Gas Diffusion Into Highly Dense Mgb2 Superconductor, Minoru Maeda, Jung Ho Kim, Y Zhao, Yoon-Uk Heo, K Takase, Y Kubota, C Moriyoshi, F Yoshida, Y Kuroiwa, S X. Dou Jun 2013

In-Field Jc Improvement By Oxygen-Free Pyrene Gas Diffusion Into Highly Dense Mgb2 Superconductor, Minoru Maeda, Jung Ho Kim, Y Zhao, Yoon-Uk Heo, K Takase, Y Kubota, C Moriyoshi, F Yoshida, Y Kuroiwa, S X. Dou

Shi Xue Dou

Oxygen-free pyrene gas as a carbon (C) dopant was delinked and incorporated into highly dense MgB2 structure via a gas phase diffusion method. The technique offers the advantages that molecular C is homogeneously distributed into MgB2 and substituted at the boron sites without any severe deterioration of grain connectivity. The C substitution causes a significant shrinkage of the a-lattice parameter and an increase in the lattice strain, resulting in high disorder. The introduction of structural disorder as a result of C doping leads to a considerable enhancement of the in-field critical current density (Jc) and upper critical field.


Synthesis And Optimization Of Fluorine-Free Y And Cu Precursor Solution For Mod Processing Of Ybco Coated Conductor, Jaimoo Yoo, Young-Kuk Kim, Kookchae Chung, Jaewoong Ko, Xiaolin Wang, S X. Dou Jun 2013

Synthesis And Optimization Of Fluorine-Free Y And Cu Precursor Solution For Mod Processing Of Ybco Coated Conductor, Jaimoo Yoo, Young-Kuk Kim, Kookchae Chung, Jaewoong Ko, Xiaolin Wang, S X. Dou

Shi Xue Dou

MOD solutions for YBCO coated conductors were synthesized with fluorine-free Y & Cu precursor. The fluorine content in the precursor solution was significantly reduced and a fast calcination profile was realized. A crack-free & thick precursor film was successfully obtained just after less than 2 hours of calcination in wet O2 atmosphere. Optimization of the precursor solution with Sm addition enables further improvement of thickness and uniformity of precursor films. The calcinated precursor film was successfully converted to dense and uniform YBCO film after annealing in wet Ar/O2 atmosphere. The measured critical current value was about 273 A/cm-w (Jc ~ …


Flux-Pinning Mechanism In Silicone-Oil Doped Mgb2: Evidence For Charge-Carrier Mean Free Path Fluctuation Pinning, Shaban R. Ghorbani, Xiaolin Wang, S X. Dou, Sung-Ik Lee, Md S. Hossain Jun 2013

Flux-Pinning Mechanism In Silicone-Oil Doped Mgb2: Evidence For Charge-Carrier Mean Free Path Fluctuation Pinning, Shaban R. Ghorbani, Xiaolin Wang, S X. Dou, Sung-Ik Lee, Md S. Hossain

Shi Xue Dou

Flux-pinning mechanism of MgB2 doped with 10 wt % silicone-oil sintered at low and high temperatures has been investigated by magnetic measurements. The field dependence of the critical current density, jc(B), was analysed within the collective pinning model. A crossover field, Bsb, from the single vortex to the small vortex bundle-pinning regime was observed. For both types of sintered samples, the temperature dependence of Bsb(T) at low temperature is in good agreement with the δl pinning mechanism, i.e., pinning associated with charge-carrier mean free path fluctuation. At temperatures close to the critical temperature, however, there is evidence for δTc pinning, …


All-Polymer Battery System Based On Polypyrrole (Ppy)/Para (Toluene Sulfonic Acid) (Pts) And Polypyrrole (Ppy)/Indigo Carmine (Ic) Free Standing Films, Irin Sultana, Md. Mokhlesur Rahman, Jiazhao Wang, Caiyun Wang, Gordon G. Wallace, Hua-Kun Liu Mar 2013

All-Polymer Battery System Based On Polypyrrole (Ppy)/Para (Toluene Sulfonic Acid) (Pts) And Polypyrrole (Ppy)/Indigo Carmine (Ic) Free Standing Films, Irin Sultana, Md. Mokhlesur Rahman, Jiazhao Wang, Caiyun Wang, Gordon G. Wallace, Hua-Kun Liu

Gordon Wallace

In this study, we introduce a novel all-polymer battery system based on conducting polymer (polypyrrole, PPy) doped with dopants of para (toluene sulfonic acid) (pTS) and indigo carmine (IC), respectively. The performance of the systems consisting of polypyrrole-para (toluene sulfonic acid) (PPy-pTS) as cathode and polypyrrole-indigo carmine (PPy-IC) as anode in conjunction with either a polymer based electrolyte or a commercial organic electrolyte of 1M LiPF6 in a 50:50 (v/v) mixture of ethylene carbonate (EC) and dimethyl carbonate (DMC) was evaluated. In the system, all the free-standing PPy-pTS and PPy-IC films were directly used without needing any metal substrate support …


Flexible Free-Standing Graphene-Silicon Composite Film For Lithium-Ion Batteries, Jiazhao Wang, Chao Zhong, Shulei Chou, Hua Liu Feb 2013

Flexible Free-Standing Graphene-Silicon Composite Film For Lithium-Ion Batteries, Jiazhao Wang, Chao Zhong, Shulei Chou, Hua Liu

Shulei Chou

Flexible, free-standing, paper-like, graphene-silicon composite materials have been synthesized by a simple, one-step, in-situ filtration method. The Si nanoparticles are highly encapsulated in a graphene nanosheet matrix. The electrochemical results show that graphene-Si composite film has much higher discharge capacity beyond 100 cycles (708 mAh g− 1) than that of the cell with pure graphene (304 mAh g− 1). The graphene functions as a flexible mechanical support for strain release, offering an efficient electrically conducting channel, while the nanosized silicon provides the high capacity.


Free-Standing Single-Walled Carbon Nanotube/Sno2 Anode Paper For Flexible Lithium-Ion Batteries, Lukman Noerochim, Jia-Zhao Wang, Shulei Chou, David Wexler Feb 2013

Free-Standing Single-Walled Carbon Nanotube/Sno2 Anode Paper For Flexible Lithium-Ion Batteries, Lukman Noerochim, Jia-Zhao Wang, Shulei Chou, David Wexler

Shulei Chou

Free-standingsingle-walledcarbonnanotube/SnO2 (SWCNT/SnO2) anodepaper was prepared by vacuum filtration of SWCNT/SnO2 hybrid material which was synthesized by the polyol method. From field emission scanning electron microscopy and transmission electron microscopy, the CNTs form a three-dimensional nanoporous network, in which ultra-fine SnO2 nanoparticles, which had crystallite sizes of less than 5 nm, were distributed, predominately as groups of nanoparticles on the surfaces of singlewalled CNT bundles. Electrochemical measurements demonstrated that the anodepaper with 34 wt.% SnO2 had excellent cyclic retention, with the high specific capacity of 454 mAh g−1 beyond 100 cycles at a current …