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T. Goto - One of the best experts on this subject based on the ideXlab platform.

  • Fabrication of filamentary potassium-doped C60 superconductors by suspension Spinning Method
    Physica C-superconductivity and Its Applications, 2004
    Co-Authors: T. Goto, M. Maezawa
    Abstract:

    Abstract This paper describes the preparation of filamentary potassium-doped C 60 superconductors prepared by the suspension Spinning Method. Commercial C 60 powder was suspended in mixed poly(vinyl alcohol) solution of dimethyl sulfoxide and hexamethylphosphoric triamide (sample A). The viscous suspension was extruded as a filament into a precipitating medium of methyl alcohol and coiled on a drum. The filamentary sample was also prepared by the suspension Spinning by using polyacrylonitrile solution of N , N -dimethylformamide (sample B). The samples were pyrolyzed to remove volatile components. Doping of potassium for the samples was prepared as following: At first, powder samples of nominal composition K 6 C 60 was prepared by reaction of C 60 with excess potassium. The K 6 C 60 powder and filamentary sample with stoichiometric ratio of K 3 C 60 were placed in Pyrex glass tubes and vacuum-sealed and heated at 250 °C for 36 h. SQUID measurement shows the superconductivity of sample B with T c =18 K. On the other hand, the superconductivity more than 2 K was not detected for sample A.

  • Angular dependence of Jc for filamentary (Nd, Eu, Gd)123 superconductors prepared by a solution Spinning Method and oxygen controlled melt growth process
    Physica C-superconductivity and Its Applications, 2001
    Co-Authors: T. Goto, Kunihiro Iwata, K. Watanabe
    Abstract:

    Abstract The filamentary (Nd 0.333 Eu 0.333 Gd 0.333 ) 1.18 Ba 2.12 Cu 3.09 O x superconductors were prepared by solution Spinning Method and partially melted in flowing 1% O 2 +Ar and then oxygenated by a two-step process. The filamentary sample had a dense and well-aligned texture along the diameter as well as the length. The J c of the sample was measured at 77 K in fields up to 10 T. Anisotropic behavior of the J c – B curve along the filament diameter was detected. High J c value of more than 3500 A/cm 2 at 77 K and 10 T was achieved by applying the field in a direction normal to the c -axis of the sample.

  • Field dependence of J/sub c/ for filamentary RE-Ba-Cu-O superconductors prepared by a solution Spinning Method
    IEEE Transactions on Appiled Superconductivity, 2001
    Co-Authors: T. Goto, K. Watanabe
    Abstract:

    The filamentary RE-Ba-Cu-O (RE=Nd, Nd-Eu-Gd, and Nd-Sm-Eu-Gd) precursor was prepared by a solution Spinning Method, through a homogeneous aqueous solution containing mixed acetates of RE, Ba and Cu, poly(vinyl alcohol) and organic acids. The filamentary precursor was partially melted in flowing 0.1%O/sub 2/+Ar or 1%O/sub 2/+Ar and then oxygenated under various conditions. The transport critical current density (J/sub c/) of the samples was measured in magnetic fields up to 10 T at 77 K. The influence of field dependence of J/sub c/ on the initial different RE elements in the filamentary RE-Ba-Cu-O superconductors was examined. The field dependence of J/sub c/ was improved by mixing three or four different RE elements. The J/sub c/ value at 77 K and up to 6 T for the sample partially melted in flowing 0.1%O/sub 2/+Ar was higher than that for the sample melted in flowing 1%O/sub 2/+Ar. The highest J/sub c/ value of more than 1.76/spl times/10/sup 4/ A/cm/sup 2/ at 77 K and 9 T was detected for filamentary Nd-Sm-Eu-Gd-Ba-Cu-O superconductors partially melted in flowing 0.1%O/sub 2/+Ar.

  • Critical current density in filamentary (Nd, Sm, Eu, Gd)–Ba–Cu–O superconductors prepared by a solution Spinning Method
    Physica C-superconductivity and Its Applications, 2000
    Co-Authors: T. Goto, Kenichiro Inagaki, K. Watanabe
    Abstract:

    Abstract The filamentary (Nd, Sm, Eu, Gd)–Ba–Cu–O (LRE123) precursor was prepared by the solution Spinning Method, through a homogeneous aqueous solution containing mixed acetates of Nd, Sm, Eu, Gd, Ba, and Cu, poly(vinyl alcohol) and organic acids. The filamentary sample was partially melted at 980°C in flowing 0.1% O 2 +Ar and oxygenated under various conditions. The transport critical current density ( J c ) for the samples was examined in magnetic fields up to 10 T at 77 K. The highest J c value of more than 1×10 4 A/cm 2 at 77 K and 9 T was achieved for the filamentary Nd 0.295 Sm 0.295 Eu 0.295 Gd 0.295 Ba 2.12 Cu 3.09 O x superconductors by controlling the oxygenation conditions.

  • Fabrication of Hg1Ba2Ca2Cu3Re0.1Ox Filament by Solution Spinning Method
    Advances in Superconductivity VIII, 1996
    Co-Authors: T. Goto
    Abstract:

    The fabrication of superconducting Hg1Ba2Ca2Cu3Re0.1Ox filament was studied through solution Spinning Method. The precursor Ba2Ca2Cu3Re0.1Ox filament with diameter of 2 50 µm was prepared by dry Spinning through a homogeneous aqueous solution containing mixed acetates of Ba, Ca and Cu, ammonium perrhenate, polyvinyl alcohol and organic acids. The as-drawn filament was pyrolyzed to remove volatile component and heated at 900°C at 1 h and then reacted in a controlled Hg atmosphere at 740°C for 24 h. The heated filament was nearly single phase of Hg 1223 phase. As compared with the Hg1(Ba0.88Sr0.2)2Ca2Cu3Re0.1Ox filament, the window of the optimum reacting condition for the single Hg1223 phase was very narrow.

Ping Zhu - One of the best experts on this subject based on the ideXlab platform.

Hu Yang - One of the best experts on this subject based on the ideXlab platform.

  • preparation of poly vinyl butyral hollow fiber ultrafiltration membrane via wet Spinning Method using pvp as additive
    Desalination, 2011
    Co-Authors: Pingyun Zhang, Yanli Wang, Hu Yang
    Abstract:

    Abstract Polyvinyl butyral (PVB) hollow fiber membranes were prepared via wet-Spinning Method using polyvinylpyrrolidone (PVP) as additive. The effects of PVP and PVB concentration, bore fluid composition on the membrane formation were investigated by viscosity, light transmission, scanning electron microscopy (SEM) and ultrafiltration respectively. Results revealed that PVB and PVP have a good miscibility. Addition of PVP mainly changed the kinetic property of the dope, such as the increased viscosity, the delayed demixing, etc. The cross-sections of the resulting membranes showed a similar asymmetric structure. Ultrafiltration showed that the rejection of membrane increased, but the flux firstly increased then decreased with an increase in PVP concentration. The low PVB concentration in the dope caused a loose cross-sectional morphology, which improved the water flux of membrane. Moreover notable difference occurred at the internal surface of PVB hollow fiber membrane when N,N-dimethulacetamide (DMAc) was added to the bore fluid. As a result, membrane exhibited a high flux with no significant change in retention performance.

Z X Guo - One of the best experts on this subject based on the ideXlab platform.

  • high performance all carbon yarn micro supercapacitor for an integrated energy system
    Advanced Materials, 2014
    Co-Authors: Qinghai Meng, Yuena Meng, Ke Xie, Zhixiang Wei, Z X Guo
    Abstract:

    Single-walled carbon nanotubes and chitosan composite yarn is prepared using a wet-Spinning Method. After thermal treatment, mesoporous all-carbon yarn is obtained. Based on this material, flexible all-solid-state yarn micro-supercapacitors are fabricated. Electrochemical results show high specific capacitance and energy density, good rate capability and stable cycling life. Results of this research offer prospect for application in portable and wearable electronics. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Jie Liu - One of the best experts on this subject based on the ideXlab platform.