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71.
J. J. Lim R. MacKenzie S. Sujecki M. Sadeghi S. M. Wang G. Adolfsson Y. Q. Wei A. Larsson P. Melanen P. Uusimaa A. A. George P. M. Smowton E. C. Larkins 《Optical and Quantum Electronics》2008,40(5-6):385-390
In this work, we optimize the thermal performance of a double quantum well GaInNAs ridge waveguide laser using an accurate in-house 2D electro-opto-thermal laser simulator. The simulator has shown good agreement with experiments after a detailed calibration procedure. Using calibrated material parameters, we investigate the influence of the cladding doping level on the heat generation within the laser. It is found that due to the competition between Joule heating and free carrier absorption, an optimum cladding doping level exists. 相似文献
72.
Lukas Pietzonka Thomas Lautenschläger Daniel Spemann Annemarie Finzel Jürgen W. Gerlach Frank Frost Carsten Bundesmann 《The European Physical Journal B - Condensed Matter and Complex Systems》2018,91(10):252
TiO2 thin films were grown by ion beam sputter deposition (IBSD) using oxygen ions, with the ion energy and geometrical parameters (ion incidence angle, polar emission angle, and scattering angle) being varied systematically. Metallic Ti and ceramic TiO2 served as target materials. The thin films were characterized concerning thickness, growth rate, surface topography, structural properties, mass density, and optical properties. It was found that the scattering geometry has the main impact on the film properties. Target material, ion energy, and ion incidence angle have only a marginal influence. Former studies on reactive IBSD of TiO2 using Ar and Xe ions reported equivalent patterns. Nevertheless, the respective ion species distinctively affects the film properties. For instance, mass density and the refractive index of the TiO2 thin films are remarkably lower for sputtering with oxygen ions than for sputtering with Ar or Xe ions. The variations in the thin film properties are tentatively attributed to the angular and the energy distribution of the film-forming particles, especially, to those of the backscattered primary particles. 相似文献
73.
Carsten Bundesmann Thomas Lautenschläge Daniel Spemann Annemarie Finzel Michael Mensing Frank Frost 《The European Physical Journal B - Condensed Matter and Complex Systems》2017,90(10):187
The correlation between process parameters and properties of TiO2 films grown by ion beam sputter deposition from a ceramic target was investigated. TiO2 films were grown under systematic variation of ion beam parameters (ion species, ion energy) and geometrical parameters (ion incidence angle, polar emission angle) and characterized with respect to film thickness, growth rate, structural properties, surface topography, composition, optical properties, and mass density. Systematic variations of film properties with the scattering geometry, namely the scattering angle, have been revealed. There are also considerable differences in film properties when changing the process gas from Ar to Xe. Similar systematics were reported for TiO2 films grown by reactive ion beam sputter deposition from a metal target [C. Bundesmann et al., Appl. Surf. Sci. 421, 331 (2017)]. However, there are some deviations from the previously reported data, for instance, in growth rate, mass density and optical properties. 相似文献
74.
The aim of this study was to investigate the potential impact of a coal combustion power plant in the northern part of Vietnam with regard to elemental pollution on the surrounding environment. Freshwater fishes (Clarias fucus) were sampled both at a site exposed to the emissions of the power plant and at a reference site seemingly free from industrial activities. The elemental concentrations in muscle and liver tissue were analyzed using total-reflection X-ray fluorescence and atomic absorption spectroscopy. A comparison of muscle tissue with International Standards (Food and Agricultural Organization) showed that the fishes from both sites did not constitute any health risk for human consumers with regard to the elements Cu, Zn, As, Se, Cd, Pb and Cr. Generally, concentration differences between sites were found to be small in the edible tissue. Compared to the muscle tissue, concentrations of metals were elevated in the liver. The elemental concentrations of P, S, K, Ca, Fe, Mn, Zn and Pb were significantly higher in the hepatic tissue from the exposed site, suggesting—together with measurements of airborne pollutants—emissions from the power plant as a probable source of these elements. 相似文献
75.
Annemarie Hetzheim 《Nachrichten aus der Chemie》2005,53(10):1027-1029
76.
Femtosecond laser pulse ablation of GaAs and InP: studies utilizing scanning and transmission electron microscopy 总被引:2,自引:0,他引:2
A. Borowiec M. MacKenzie G.C. Weatherly H.K. Haugen 《Applied Physics A: Materials Science & Processing》2003,77(3-4):411-417
Single pulse laser ablation of GaAs and InP using 130 fs light pulses at 800 nm was studied with various techniques, in particular, scanning and transmission electron microscopies. The final state of the material near the laser-ablated region following femtosecond ablation was characterized in detail for selected laser fluences. Threshold ablation laser fluences were also obtained for both compounds. PACS 61.80.Ba; 64.60.-i; 79.20.Ds 相似文献
77.
78.
J H Bochner K B Snell D J MacKenzie 《The Journal of the Acoustical Society of America》1988,84(2):493-500
The ability to discriminate changes in the length of vowels and tonal complexes (filled intervals) and in the duration of closure in stop consonants and gaps in tonal complexes (unfilled intervals) was studied in three normally hearing and seven severely hearing-impaired listeners. The speech stimuli consisted of the vowels (i, I, u, U, a, A) and the consonants (p, t, k), and the tonal complexes consisted of digitally generated sinusoids at 0.5, 1, and 2 kHz. The signals were presented at conversational levels for each listener group, and a 3IFC adaptive procedure was used to estimate difference limens (DLs). The DLs for speech were similar to those for tonal complex stimuli in both the filled and unfilled conditions. Both normally and impaired-hearing listeners demonstrated greater acuity for changes in the duration of filled than unfilled intervals. Mean thresholds for filled intervals obtained from normally hearing listeners were smaller than those obtained from hearing-impaired listeners. For unfilled intervals, however, the difference between listener groups was not significant. A few hearing-impaired listeners demonstrated temporal acuity comparable to that of normally hearing listeners for several listening conditions. Implications of these results are discussed with regard to speech perception in normally and impaired-hearing individuals. 相似文献
79.
80.
J. Voss A. Popoff Leopold Schmid Annemarie Polaczek-Wittek H. Linser E. Lundsteen E. Bamann W. Salzer E. Vermehren S. Thannhauser M. Reichel J. Grattan A. V. Iyengar I. Reifer E. Knippenberg F. Alten E. Rauterberg M. Chopin A. Niethammer N. S. Skrosnikowa und O. Richter 《Fresenius' Journal of Analytical Chemistry》1941,121(3-4):153-160
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