Entity

Time filter

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Livermore, CA, United States

Zhu Y.,University of California at Irvine | Qiu G.,Broadcom Corporation | Chi K.H.,University of California at Irvine | Wang B.B.T.,Wang Nmr Inc. | And 2 more authors.
IEEE Transactions on Magnetics | Year: 2010

In this paper, a compact X-band tunable Bandpass Filter (BPF) module which employs a pair of passive microstrip composite-BPFs in cascade on RT/Duroid 6010 substrate is reported. The passive microstrip composite-BPF was realized by combining four open-circuited stubs of a microstrip X-band BPF with four inductive elements of a stepped impedance low-pass filter. Placement of one YIG/GGG layer upon each of the passive microstrip composite-BPFs enables the resulting composite-BPFs to function simultaneously as an X-band BPF and a tunable Band-Stop Filter. By tuning the bias magnetic fields to 1780 and 2670 Oe, 2450 and 3250 Oe, and 1780 and 3 250 Oe on the pair of the composite-BPF, respectively, the passband of the module was tuned toward the high end, the low end, and the center frequencies. The corresponding center frequencies of 12, 7.9 and 10 GHz, minimum 3 dB bandwidth of 0.6, 0.4, and 0.5 GHz, respectively, and an insertion loss of 2.5 dB were measured. Compared to the BPF module reported recently, reductions of 43.5% in circuit area and 52.8% in insertion loss were achieved. The minimum 3 dB bandwidth was narrowed by 40%, 63.6%, and 58.3%, and its tuning ranges were extended from 3.7, 3.6, and 3.5 GHz to 4.1, 4.3, and 4.2 GHz, respectively. This newly realized tunable BPF module has demonstrated superior features such as more compact device structure, smaller device dimensions, lower insertion loss, and improved frequency tunability and selectivity. © 2006 IEEE. Source


Grant
Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase II | Award Amount: 749.99K | Year: 1995

Breast cancer mortality will be drastically reduced if tumors are diagnosed and removed as early as possible before the onset of metastasis. On the basis of data from the groups working with contract-enhanced MRM, it can be expected that MRM will in the next century replace conventional mammography as the chosen procedure for breast imaging. Since the current MRM is more expensive than conventional mammography, its increased application will accelerate if a special inexpensive MRM devices appear on the market. A low cost, open air, self-shielded superconducting MRM has been designed and proposed. The MRM will enable the patient to be examined in the open air with surface coils very accessible for breast biopsy. The patient can be maneuvered around, so the magnet only needs to produce a smaller volume of high resolution magnetic field. Therefore, the overall physical size and the cost of the MRM will be significantly reduced. Since the MRM is self-shielded, the cost of any facility construction, remodeling or shielding will be eliminated. We will (1) design "C" shaped split gap 1.0 T self shielded superconducting MRM and (2) design a table top 0.5 T or vertical superconducting wall permanent magnets composed of high temperature superconductors. These designs will have sufficient details to allow the selection of construction of a low cost MRM in Phase II.


Grant
Agency: Department of Energy | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 100.00K | Year: 2006

Nuclear physics research programs would benefit substantially from a superconducting spectrometer that provides a highly-uniform high field (5T), large bore, good resolution, and a large solid angle. This project will develop a state-of-the-art superconducting magnet for such a spectrometer. The magnet will be built with high Tc wire, high Tc leads, and a cryocooler. In Phase I, design calculations and analysis of the magnet will be completed. The design will include a 5 T, 50 cm uniform-field solenoid with Hi Tc wire, Hi Tc leads, and a cryocooler. In Phase II, the magnet will be constructed and tested. Commercial Applications And Other Benefits as described by the Applicant: Beyond the application for the nuclear physics research program, the technology should be applicable to MRI magnets


Arbelaez D.,Lawrence Berkeley National Laboratory | Black A.,Lawrence Berkeley National Laboratory | Prestemon S.O.,Lawrence Berkeley National Laboratory | Wang S.,Wang Nmr Inc. | And 2 more authors.
IEEE Transactions on Applied Superconductivity | Year: 2011

An eight-pole superconducting magnet is being developed for soft x-ray magnetic dichroism (XMD) experiments at the Advanced Light Source, Lawrence Berkley National Laboratory (LBNL). Eight conical Nb3Sn coils with Holmium poles are arranged in octahedral symmetry to form four dipole pairs that provide magnetic fields of up to 5 T in any direction relative to the incoming x-ray beam. The dimensions of the magnet yoke as well as pole taper, diameter, and length were optimized for maximum peak field in the magnet center using the software package TOSCA. The structural analysis of the magnet is performed using ANSYS with the coil properties derived using a numerical homogenization scheme. It is found that the use of orthotropic material properties for the coil has an important influence in the design of the magnet. © 2011 IEEE. Source


Grant
Agency: Department of Health and Human Services | Branch: | Program: SBIR | Phase: Phase I | Award Amount: 49.95K | Year: 1993

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