227 research outputs found

    Eddy-Current Testing Probe With Spin-Valve Type GMR Sensor for Printed Circuit Board Inspection

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    This paper proposes an eddy-current testing (ECT) probe composed of a spin-valve giant magnetoresistance (SV-GMR) sensor and a meander coil for the inspection of bare printed circuit board. The SV-GMR sensor serves as a magnetic sensor for the ECT probe to sense the variation of the magnetic field distribution occurred on the printed circuit board. The SV-GMR sensor is used specifically to detect the changing magnetic field distribution occurred at the defect point. The characteristics of the proposed probe are discussed in this paper. The comparisons of signal-to-noise ratios obtained from ECT probe with SV-GMR sensor and with solenoid coil verify that the applying of SV-GMR sensor to the ECT probe can improve the PCB inspection results

    Boundary Action of N=2 Super-Liouville Theory

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    We derive a boundary action of N=2 super-Liouville theory which preserves both N=2 supersymmetry and conformal symmetry by imposing explicitly T=TˉT={\bar T} and G=GˉG={\bar G}. The resulting boundary action shows a new duality symmetry.Comment: 15 pages; One reference is adde

    Recent Advances in Ultrasound Imaging of Breast Lesions

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    Helminth parasites are known to elicit the immune response towards T helper 2 (Th2)-type, characterized by Th2 related cytokines, that typically include interleukin-4 (IL-4), IL-5 and IL-13. In this review we will describe the mechanisms involved in helminth induced Th2 immune response. Intestinal epithelial cells (IECs) produce thymic stromal lymphopoietin (TSLP), which is both necessary and sufficient for the initiation of Th2 cytokine-driven inflammation. IL-33 mRNA is expressed early during parasite infection and IL-33 binds ST2 receptor, both of which are associated with optimal CD4+ Th2 polarization. Following innate immune cell recognition, basophils and mast cell can secrete Th2 type cytokines that are thought to contribute to CD4+ Th2 differentiation. Additionaly, dendritic cell conditioned with some helminth products can promote CD4+ Th2 differentiation. Alternatively activated macrophages, activated by the Th2 cytokines IL-4 and IL-13 in parasitic infections, contribute to the host protective response: control of Th1-type inflammation, wound healing and worm expulsion. Experimentally, helminths have been associated with protection against a number of autoimmune disorders, including inflammatory bowel diseases and type 1 diabetes. It may be a novel strategy to ameliorate autoimmune inflammation by expanding and activating the Th2 response originated from parasites

    Inspection of the PCB Defects by using ECT technique with GMR sensor

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