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61.
Douay M. Xie W.X. Taunay T. Bernage P. Niay P. Cordier P. Poumellec B. Dong L. Bayon J.F. Poignant H. Delevaque E. 《Lightwave Technology, Journal of》1997,15(8):1329-1342
A comprehensive survey of photosensitivity in silica glasses and optical fiber is reviewed. Recent work on understanding the mechanisms contributing to germanium or aluminum doped fiber photosensitivity is discussed within the framework of photoelastic densification models 相似文献
62.
Cresswell M.W. Allen R.A. Guthrie W.F. Sniegowski J.J. Ghoshtagore R.N. Linholm L.W. 《Semiconductor Manufacturing, IEEE Transactions on》1998,11(2):182-193
The physical widths of reference features incorporated into electrical linewidth test structures patterned in films of monocrystalline silicon have been determined from Kelvin voltage measurements. The films in which the test structures are patterned are electrically insulated from the bulk-silicon substrate by a layer of silicon dioxide provided by SIMOX (Separation by the IMplantation of OXygen) processing. The motivation is to facilitate the development of linewidth reference materials for critical-dimension (CD) metrology-instrument calibration. The selection of the (110) orientation of the starting silicon and the orientation of the structures' features relative to the crystal lattice enable a lattice-plane-selective etch to generate reference-feature properties of rectangular cross section and atomically planar sidewalls. These properties are highly desirable for CD applications in which feature widths are certified with nanometer-level uncertainty for use by a diverse range of CD instruments. End applications include the development and calibration of new generations of CD instruments directed at controlling processes for manufacturing devices having sub-quarter-micrometer features 相似文献
63.
Approaches to using visual language in a cultural context can be placed on a continuum, with global (universal) on one end and culture-focused on the other. Each approach reveals contrasting assumptions about three central design issues: perception, aesthetics and pragmatics. The global approach is characterized by attempts to invent an objective, universal visual language or to define such a language through perceptual principles and empirical research. The culture-focused perspective is founded on the principle that visual communication is intimately bound to experience and hence can function only within a given cultural context, to which designers must be sensitive. While the modernist, universal approach has been losing ground to the postmodern, culture-focused approach, the two complement each other in a variety of ways and, depending on the rhetorical situation, offer pragmatic benefits and drawbacks 相似文献
64.
Good access to health facilities providing good first-level health care remains problematic in many developing countries. It is a hindrance to effective and efficient functioning of the hospital, as outpatient departments become overcrowded with patients from areas without health centres. In many cases the quality of care delivered to these patients is poor because within the district health system the hospital is not the best place for the supply of comprehensive, integrated and continuous care. Eventually, high hospital involvement in first-level care can jeopardize the delivery of adequate referral care for those patients who desperately need the hospital's technology and expertise. This paper provides an account of the way this problem was investigated and managed by the district health management team in the Murewa district in north-east Zimbabwe. The design of a comprehensive 'master plan' or 'coverage plan' is presented as well as the problems and difficulties encountered. The Murewa experience highlights the relevance of a coverage plan for rational and coherent health infrastructure planning at district level. The approach followed by the Murewa team illustrates the use of action research as an integral part of the management of district health systems. 相似文献
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66.
Furst C. Leitenstorfer A. Laubereau A. 《IEEE journal of selected topics in quantum electronics》1996,2(3):473-479
An experimental and theoretical analysis of the nonlinear coupling mechanism between the two solitary pulses circulating in a two-color femtosecond laser is presented. Two operation regimes; synchronized; and nonsynchronized; and a hysteresis of the transition between the two regimes are clearly observed; while independent modelocking and tunability of the output pulse trains is found in both regimes. Pulses in the range from 15 to 100 fs are synchronized with a timing jitter below 2 fs. The combined effects of cross-phase modulation and negative group velocity dispersion are shown to be responsible for the strong pulse correlation in the synchronized regime. Our experimental observations are in agreement with numerical simulations, thus confirming the theoretical model 相似文献
67.
Surveyed 70 practicing attorneys and 150 law students to determine the extent to which they felt it was their responsibility to inform clients they referred for psychological testing about the testing process and about the validity scales on tests. Results showed that almost 50% of the attorneys and over 33% of the students believe that clients referred for testing always or usually should be informed of validity scales on tests. These results suggest that many test takers, particularly in forensic settings, may have information about validity scales that facilitates their giving biased responses without detection. Psychologists doing forensic evaluations should be alert to this possibility and should consider using more than one approach to detect response distortions. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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