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Applied Superconductivity, IEEE Transactions on

Issue 2 • Date April 2010

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Displaying Results 1 - 13 of 13
  • [Front cover]

    Page(s): C1
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  • IEEE Transactions on Applied Superconductivity publication information

    Page(s): C2
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  • Table of contents

    Page(s): 53
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  • System-Level Studies of a \hbox {MgB}_{2} Superconducting Fault-Current Limiter in an Active Distribution Network

    Page(s): 54 - 60
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (354 KB) |  | HTML iconHTML  

    Superconducting fault-current limiters are being considered as a potential technology for restricting fault current to acceptable levels without extensive and costly network asset replacement. Such an issue currently arises primarily from the connection of a distributed generation. This paper first investigates the fault studies of an active medium-voltage distribution network with several superconducting fault-current-limiter deployment strategies and then considers their impact on circuit-breaker transient recovery voltage. These circuit-breaker characteristics at various voltage levels have been studied, and it is demonstrated that the superconducting fault-current limiter is capable of reducing both the magnitude and the rate of rise of the transient recovery voltage. View full abstract»

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  • Structural and Transport Properties of the ( \hbox {Bi}_{1.6}\hbox {Pb}_{0.5})(\hbox {Sr}_{2-x}\hbox {Lu}_{x})\hbox {Ca}_{1.1}\hbox {Cu}_{2.1}\hbox {O}_{8 + \delta } Superconductor

    Page(s): 61 - 65
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (522 KB) |  | HTML iconHTML  

    The effects of Lu-doping on phase evolution, microstructure, electrical, and superconducting properties of Bi-2212 have been studied. The results show that Lu+3 ions enter into the crystal structure in place of Sr+2 ions and, hence, reduce the hole concentration in the electronic structure of the system. Lu-doping results in the reduction of c-axis length and increases the Josephson coupling between the Cu-O2 layers at lower Lu-contents. The critical temperature Tc and the critical current density Jc are significantly enhanced for optimum Lu concentration. The variations in the electrical and superconducting properties are due to the structural and electronic inhomogeneities and changes in charge carrier concentration due to Lu-doping in the (Bi, Pb)-2212 superconductor. View full abstract»

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  • Enhanced Growth Rate of a YBCO Bulk in the Melt-Textured Process Under 1 atm Oxygen Pressure

    Page(s): 66 - 70
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (373 KB) |  | HTML iconHTML  

    By the employment of 1 atm oxygen pressure as the growth atmosphere, we report a success in the enhanced growth rate of the melt-textured (MT) YBCO bulk. A well-oriented c -axis single-domain bulk with a size of 42 mm in diameter was fully grown at a high average growth rate of about 0.32 mm/h, which is 1.5 times larger than that in air. It was found that the increased oxygen partial pressure has a profound influence on the MT growth (MTG) for YBCO. The enhanced growth rate can be interpreted by both increased solubility and diffusion coefficient of yttrium in the Ba-Cu-O liquid under high oxygen partial pressure. After oxygenation, single-domain samples were determined to have a sharp superconducting transition temperature at 91.7 K, indicating that the superconductivity of crystals grown under high oxygen pressure does not degrade. Additionally, due to the rapid growth, the trapping effect of Y211 particles becomes predominant. As a result, a relatively more homogeneous distribution of Y211 particles was observed in the Y123 matrix. Finally, the most important advantage of this technique is that the enhanced growth rate of Y123 gives less opportunity from self-nucleation in the liquid, which takes place beyond the growth window and the embryonic period. Thus, this oxygen-increased MTG process is very promising for producing large-sized YBCO bulks with good superconducting properties. View full abstract»

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  • Improved Fabrication Yield for 10-V Programmable Josephson Voltage Standard Circuit Including 524288 NbN/TiN/NbN Josephson Junctions

    Page(s): 71 - 75
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (312 KB) |  | HTML iconHTML  

    A 10-V programmable Josephson voltage standard (PJVS) circuit including 524 288 vertically stacked NbN/TiN/NbN Josephson junctions was successfully fabricated without any defects. The chip was cooled with a compact cryocooler at a temperature of 9.8 K and generated an output voltage of 17.3 V with the first Shapiro step height of 1.0 mA under microwave irradiation at 16 GHz. Furthermore, the circuit design having the high output voltage increased the number of available chips for the 10-V PJVS. The fabrication yield for the chip, which generates greater than 10 V, was 36%, which is ten times greater than that for a perfect chip without any defects. This method was not effective for the chip that had serious defects, such as a disconnection across the array or short between the array and ground; thus, efforts to reduce such defects, e.g., frequent maintenance inside vacuum chambers for film preparation and etching, were found to be essential. View full abstract»

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  • An Efficient Finite-Element Approach for the Modeling of Planar Double-D Excitation Coils and Flaws in SQUID NDE Systems

    Page(s): 76 - 81
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (998 KB) |  | HTML iconHTML  

    Incorporating an efficient approach for the finite-element simulation of eddy current superconductive quantum interface device (SQUID) nondestructive evaluation (NDE) systems, an appropriate finite-element method (FEM) has been presented for simulating and analyzing such systems. We have introduced a new model for the planar double-D coils, which are used as the excitation source in eddy current SQUID NDE systems, and also another model for the description of the flaw effect on the induced current. We have also examined our simulation results with their associated measurements. Our system is based on a high-TC YBCO gradiometer RF-SQUID sensor with a flux noise level below 100 ????0/ ??Hz at 100 Hz in an unshielded environment while being shielded against external RF electromagnetic interference. The very good agreement between experimental and numerical approaches confirmed our model for the 3-D FEM simulation of the system, which is being done in reasonable time and using reasonable computer resources. View full abstract»

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  • J_{C}(B) Determination Method With the Help of the Virgin Magnetization Curve of a Superconducting Cylinder

    Page(s): 82 - 86
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    It is well known that the critical current density JC of a superconducting material depends on the magnetic flux density B . For practical applications, it is essential to have accurate information about JC(B) , which can be obtained from different experimental techniques (transport current, hysteretic cycle, and ac susceptibility). This paper presents a simple and quick JC(B) experimental determination method for a superconducting cylinder. A first JC(B) experimental evaluation method consists of measuring the magnetization cycle M(B) and determining the width of this cycle for each value of B. This is generally done using the Bean model, where JC is considered constant. A more accurate method is presented in this paper. The cylinder first magnetization curve M 1(B) is calculated with the Kim model [ JC(B) = JC0/(1 + (|B|/BC0))] and with a linear model and compared with the measured first magnetization curve M 1mea(B). In so doing, JC0 and BC0 are determined, and the results obtained using both JC(B) determination methods are compared and discussed. View full abstract»

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    Page(s): 87
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    Page(s): 88
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  • IEEE Transactions on Applied Superconductivity upcoming special conference issues

    Page(s): C3
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  • IEEE Transactions on Applied Superconductivity Information for authors

    Page(s): C4
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Aims & Scope

IEEE Transactions on Applied Superconductivity contains articles on the applications of superconductivity and other relevant technology.

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Meet Our Editors

Editor-in-Chief
Britton L. T. Plourde
Syracuse University
bplourde@syr.edu
http://www.phy.syr.edu/~bplourde