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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Applied physics 59 (1994), S. 245-251 
    ISSN: 1432-0630
    Keywords: 71.00 ; 61.70
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract An electron trap having an energy level of 0.14 eV from the conduction band edge was found in the bulk of copper-diffused VPE-grown n-GaAs0.6P0.4 by conventional DLTS measurements and by pulse-duration dependent capacitance amplitude measurements. The capture cross section at room temperature is about 1.0×10−21 cm2 and has a weak temperature dependence. These properties are attributed to a non-repulsive center having a capturing mechanism which involves multiphonon emission processes with hardly any lattice relaxation. Evolution of the spatial distributions of the traps with time under junction electric field were studied. The results suggest that the trap is positively charged and has a high diffusivity under electric field. The center can thus be identified as positively charged interstitial copper ion rather than some form of copper complexes.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0509
    Keywords: Behçet's disease ; Colitis, Behçet's ; Colon
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract We performed a retrospective review of double-contrast barium enema examinations of 20 patients with clinically proven Behçet's colitis. Main lesion was ovoid or geographic ulcers with a mean diameter of 2.7 cm. The number of ulcers was single in 15 cases and multiple in five. On six resected specimens, ulcers involved submucosa in three, muscle layer in one, and serosa in two cases with an undermining tendency and transmural inflammation. Aphthous ulcers were present in three cases. Neither perforation nor fistula was demonstrated. In all 20 patients, the ulcer was localized in the ileocecal area, with extension to the ascending colon in seven. Skip lesions were observed in the transverse colon and descending colon in three cases. Destruction of surrounding mucosa resulted in cecal contraction in 19 cases, widening of the ileocecal valve in 19, and fold thickening in the terminal ileum in 12. Six cases (30%) manifested as ileocecal mass accompanied by ulcer, fold thickening, and adjacent mucosal deformity. The appendix was visualized in only three (20%) of the 15 patients with no history of appendectomy. On follow-up study of 15 cases, the ulcers disappeared or decreased in size in 13 cases (86%) and the mucosal deformity was not improved in all cases. On the basis of our results, we believe that the characteristic findings of colitis in Behçet's disease in barium enema examination are ovoid or geographic, relatively large, and deep ulcerations with persistent surrounding deformity which tend to localize in the ileocecal area.
    Type of Medium: Electronic Resource
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