383 research outputs found

    Theoretical analysis of Wolter/LSM X-ray telescope systems

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    A ray tracing analysis has been performed for the spectral slicing zoom X-ray telescope for configurations in which a convex layered synthetic microstructure (LSM) optic is placed in front of the prime focus or a concave LSM optic is placed behind the prime focus. The analysis has considered the geometrical shape of the LSM optic to be either a hyperboloid, sphere, ellipsoid or constant optical path aspheric element for two configurations of the glancing incidence X-ray telescope: the ATM Experimental S-056 Wolter I system and the Stanford/MSFC Wolter-Schwarzchild nested system. For the different systems the RMS blur circle radii, the point spread function (PSF), the full width half maximum (FWHM) of the PSF have been evaluated as a function of field angle and magnification of the secondary to determine resolution of the system. The effects of decentration and tilt of the selected LSM element on the performance of the system have been studied to determine mounting and alignment tolerances

    Theoretical design and analysis of the layered synthetic microstructure optic for the dual path X-ray telescope

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    A ray tracing analysis was performed for several configurations for the inner channel of the dual path X-ray telescope, which is proposed to use the second mirror of the Stanford/MSFC Wolter-Schwarzchild telescope and a normal incident layered synthetic microstructure (LSM) mirror to form a secondary image near the front of the telescope. The LSM mirror shapes considered were spherical, ellipsoid, hyperboloid, and constant optical path length (OPL) aspheric. Only the constant OPL case gave good axial resolution. All cases had poor off axis resolution as judged by the RMS blur circle radius

    Theoretical analysis of segmented Wolter/LSM X-ray telescope systems

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    The Segmented Wolter I/LSM X-ray Telescope, which consists of a Wolter I Telescope with a tilted, off-axis convex spherical Layered Synthetic Microstructure (LSM) optics placed near the primary focus to accommodate multiple off-axis detectors, has been analyzed. The Skylab ATM Experiment S056 Wolter I telescope and the Stanford/MSFC nested Wolter-Schwarzschild x-ray telescope have been considered as the primary optics. A ray trace analysis has been performed to calculate the RMS blur circle radius, point spread function (PSF), the meridional and sagittal line functions (LST), and the full width half maximum (PWHM) of the PSF to study the spatial resolution of the system. The effects on resolution of defocussing the image plane, tilting and decentrating of the multilayer (LSM) optics have also been investigated to give the mounting and alignment tolerances of the LSM optic. Comparison has been made between the performance of the segmented Wolter/LSM optical system and that of the Spectral Slicing X-ray Telescope (SSXRT) systems

    Analysis of NOAA-MSFC GOES X-ray telescope

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    The general telescope system was assumed to be a paraboloid-hyperboloid in a Wolter Type 1 configuration. The equations which specify the telescope parameters and the resolution as a function of the collecting area are discussed as well as the spot size and point response function for off-axis rays. The measured resolution of the Goddard ATM X-ray telescope (S-056) is compared to the rms blur circle radius and the full width half maximum of the line spread function. An empirical scaling formula, Eq. 26, which transforms the rms blur circle radius into a more accurate measure of resolution, is introduced. The geometrical imaging properties of the proposed NOAA-MSFC GOES X-ray telescope are considered. Conclusions and alternate mirror designs are included

    Advanced water window x-ray microscope design and analysis

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    The project was focused on the design and analysis of an advanced water window soft-x-ray microscope. The activities were accomplished by completing three tasks contained in the statement of work of this contract. The new results confirm that in order to achieve resolutions greater than three times the wavelength of the incident radiation, it will be necessary to use aspherical mirror surfaces and to use graded multilayer coatings on the secondary (to accommodate the large variations of the angle of incidence over the secondary when operating the microscope at numerical apertures of 0.35 or greater). The results are included in a manuscript which is enclosed in the Appendix

    Reliability Testing of AlGaN/GaN HEMTs Under Multiple Stressors

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    We performed an experiment on AlGaN/GaN HEMTs with high voltage and high power as stressors. We found that devices tested under high power generally degraded more than those tested under high voltage. In particular, the high-voltage-tested devices did not degrade significantly as suggested by some papers in the literature. The same papers in the literature also suggest that high voltages cause cracks and pits. However, the high-voltage-tested devices in this study do not exhibit cracks or pits in TEM images, while the high-power-tested devices exhibit pits

    Pharmacokinetics of 111In-labeled OC-125 antibody in cancer patients compared with the 19-9 antibody

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    We recently reported on the pharmacokinetics in 14 cancer patients of the 19-9 antibody radiolabeled with 111In. We have now repeated this investigation in 18 cancer patients using the OC-125 antibody, in part to compare the in vivo behavior of two murine monoclonal antibodies of the same subclass administered as the F(ab\u27)2 fragments, by the same route and at the same dose. As in the earlier investigation, 1 mg of fragments was infused i.v., and organ quantitation was obtained for up to 72 h along with frequent blood and urine samples for chromatographic evaluation. Analysis of urine showed that activity clearance by this route amounted to 0.29%/h and consisted of labeled DTPA only in early samples and metabolic products thereafter. Analysis of serum samples often showed the presence of a high-molecular-weight species appearing within 24 h. This species is probably due to antibody binding to circulating antigen, although the percentage of circulating activity present as this species did not correlate well with circulating antigen levels. As before, organ accumulation was greatest in the liver, although levels were significantly reduced (12% compared to 20% of administered dose at 24 h, P less than 0.01). Plasma clearance was also significantly different: whereas the label in the case of the OC-125 antibody showed one-compartment clearance kinetics and remained in the plasma compartment, in the 19-9 case the label diffused to a second, unidentified compartment

    A description of the salinity regimes of major South Carolina estuaries

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    South Carolina has a wide variety of coastal river systems, which include extensive systems with a large freshwater discharge. These estuaries are import ant not only for their freshwater discharge, but also for their finfish and shellfish populations and for their scenic and recreational value. The goal of this study was to determine spatial and temporal salinity trends in major South Carolina estuaries on a long-term basis. This study has provided a long-term description of salinity regimes in major South Carolina estuaries
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