1,721,138 research outputs found
Modified Range Migration Algorithm for Airborne Squint Mode Spotlight SAR Data processing
No full textRange migration algorithm for airborne squint mode spotlight SAR imaging
No full textSince the reference signal based on the fixed reference range is used in the range migration algorithm (RMA), the RMA is not available to process an airborne squint-mode spotlight synthetic aperture radar (SAR) data. Thus, the modified reference signal to transform a squint-mode data to a broadside-mode data is introduced on the basis of the coordinate transformation and the extended Taylor approximation. Then, using the principle of the stationary phase, the presented formulation is analysed. Moreover, to compensate curvature errors, the proposed method is extended on the basis of the subarea technique. Finally, the effectiveness of the proposed method is demonstrated by some numerical simulations via a pulsed spotlight SAR simulator
Characterization of humic substances present in landfill leachates with different landfill ages and its implications
No full textHumic and fulvic acids extracted from landfill leachates were characterized using elemental analysis and various spectroscopic methods. Molecular size distribution of the humic substances (HS) was also determined using batch ultrafiltration technique and permeation coefficient model. The element analysis and spectral features obtained from UV/visible. IR, and H-1 and C-13 NMR showed that the aromatic character in the leachate HS was relatively lower than that of commercial humic acid (Aldrich Co.), and higher in the HS of older landfill leachate. Fluorescence spectra indicated that humic acids had a relatively higher content of condensed aromatic compounds than the fulvic acids obtained from the same Sources, and the spectrum of commercial humic acid showed that aromatic compounds may be present in a much more condensed and complex form. Molecular size distribution data revealed that the leachate humic acids contained a higher percentage of smaller molecules of < 10.000 D, compared with that of the commercial humic acid (45 similar to 49% vs. 33%), and molecular size of the leachate HS had a tendency to increase as landfill age increased. These results indicate that the HS from landfill leachates were in an early stage of humification, and the degree of humification increased as the landfilling age increased, which implies important information on various related researches, such as interactions of HA with pollutants in terrestrial environments, and optimization of leachate treatment processes with respect to landfill age. (C) 2002 Elsevier Science Ltd. All rights reserved
Lattice deformation of Sn nanowires for the application to nano-interconnection technology
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A new embryonic stem cell line with germ-line competence in the FvB/N background
No full textA new embryonic stem (ES) cell line, H3, has been established from a 3.5-day p.c. blastocyst of the 129/sv strain of mice. The degree of germ-line competence of this cell line was compared with that of J1 sublines in the FvB/N host background, an albino inbred strain which is preferably used in the generation of transgenic mice via pronucleus injection. All chimeras of the FvB/N background derived from H3 or J1 cells showed a low degree coat color chimerism. However, contrary to the previous report on the germ-line incompatibity of the FvB/N strain with 129-derived ES cells, H3 cells gave germ line transmissions in five out of six FvB/N based chimeras. This property of H3 cells contrasted with those of J1 cells which did not give any significant germ line transmission from chimeras made in the same FvB/N host whereas they were efficient in forming a germ-line chimerism in the C 57BL/6J background. These results conform to the previous observations by others that the germ-line compatibility of ES cells with a host strain is dependent on clonal lines. FvB/N mice are known to be a robust breeder and the females respond well to hormone-induced superovulation yielding a large number of germ-line compatible blastocysts. Such advantages of FvB/N may be utilized in the study of gene targeting when this host is combined with H3 ES cells, and will results in saving costs and efforts required for such experiments.
Colored Prufer codes for k-edge colored trees
No full textA combinatorial bijection between k-edge colored trees and colored Prufer codes for labelled trees is established. This bijection gives a simple combinatorial proof for the number k(n-2)!(nk-n/n-2) of k-edge colored trees with n vertices
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