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  • 1
    Electronic Resource
    Electronic Resource
    Arrhenius parameters for the rate process leading to catastrophic damage of AlGaAs-GaAs laser facets (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 71 (1992), S. 4848-4853 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The time dependence of catastrophic optical mirror damage (COMD) is investigated for cw operation of AlGaAs-GaAs quantum well lasers. The apparent Arrhenius parameters (i.e., the activation energy and pre-exponential factor) for the rate process leading to COMD are determined. In particular, we compare the rate process for various cleaved facets with and without a subsequent plasma oxidation step. Analysis of the experimental Arrhenius parameters indicates that surface reactions on the corroded facets are responsible for facet degradation accompanied by heating. A tentative model of the facet heating that ultimately leads to COMD is presented.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.350628
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  • 2
    Electronic Resource
    Electronic Resource
    Low temperature magnetic force microscopy (1993)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 2920-2925 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: We have built a low temperature scanning force microscope which is able to measure contact and noncontact forces using the dc modes of force microscopy. We demonstrate the capabilities of our instrument on a magneto-optical disk at room temperature and at 77 K. Using a ferromagnetic thin film tip, the topography and the micromagnetic stray field of the sample is measured using the dc modes of force microscopy. The topographic and magnetic data are precisely correlated. The circular bit structure and the natural domain structure between the homogeneously magnetized bits is clearly visible. A lateral resolution below 100 nm and a force resolution of 10−12 N is reproducibly achieved.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1144383
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  • 3
    Electronic Resource
    Electronic Resource
    Generation of 41 mW of blue radiation by frequency doubling of a GaAlAs diode laser (1990)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 56 (1990), S. 2291-2292 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A monolithic ring resonator of KNbO3 was used for efficient frequency doubling of a 856 nm GaAlAs diode laser. A special electronic servo technique was devised to lock the diode laser frequency to the KNbO3 cavity so that stable generation of blue output was obtained. With 105 mW of incident near-infrared power, 41 mW of 428 nm radiation were produced. The conversion efficiency from electrical input power into the diode laser to blue output was ∼10%.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.102943
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  • 4
    Electronic Resource
    Electronic Resource
    High-power operation of strained InGaAs/AlGaAs single quantum well lasers (1991)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 59 (1991), S. 2642-2644 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The high-power integrity of strained single quantum well InGaAs/AlGaAs lasers grown by molecular beam epitaxy is investigated. In the high-power regime, the lifetime of the Lz=7 nm strained quantum well laser emitting at (approximately-equal-to) 980 nm is found to be limited by the air-cleaved facets. However, a comparison with lattice-matched 7 nm quantum well GaAs/AlGaAs lasers, which otherwise have an almost identical vertical structure shows a substantial lifetime improvement. This indicates that lattice hardening due to the indium in the quantum well is effective in the facet region. The investigations demonstrate the feasibility of 150 mW single mode operation with sufficient lifetime for practical applications in the wavelength range of (approximately-equal-to)1 μm.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.105924
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  • 5
    Electronic Resource
    Electronic Resource
    Thermodynamics of facet damage in cleaved AlGaAs lasers (1991)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 59 (1991), S. 522-524 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The time dependence of catastrophic optical mirror damage (COMD) is investigated for the cw operation of AlGaAs quantum well lasers with cleaved unprotected and protected mirrors. Based on the rate equation for a COMD failure it is found that facet heating leading to COMD depends on the quantum wells and on the reflectivity modification of the protected mirrors. The investigations show that control of damage in the mirror region of the AlGaAs lasers is feasible and leads to very reliable devices.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.105426
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  • 6
    Electronic Resource
    Electronic Resource
    Comparison of Displacement and Mixing Diffusers (1992)
    Oxford, UK : Munksgaard International Publishers
    Indoor air 2 (1992), S. 0 
    Details
    ISSN: 1600-0668
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Architecture, Civil Engineering, Surveying , Medicine
    Notes: In order to cumpare the peformance of different supply diffuers of ventilation air, the airflow passern, temperature stratifiation and contaminant dispersion in a furnitured office ventilated by three kinds of air diffuer were numerically investigated. The air diffuers studied in this paper are a quarter-cylinder displacement diffuer on the floor and mixing diffuers (linear and vortex diffuers) on the ceiling. The heat sources in the of-fice are considered to be 50% convective and 50% radiative. The k-ɛ two-equatwn model of turbulence is employed to predict the turbulent diffusion.The results show that the displacement diffuser provides a rather uniform flow field with low velocify in most areas, and the vertical temperature difference from floor to ceiling is as high as 6 K. With the linear diffuser, the air velociry is high, and the temperature is uniform both horizontally and vertically. The air velocity generated by the vortex diffuser is moderate. The distributions of the temperature and the contaminant are rather uniform.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-0668.1992.05-23.x
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  • 7
    Electronic Resource
    Electronic Resource
    Acute jejunal ileus in intestinal lymphangiectasia (1993)
    Springer
    Journal of molecular medicine 71 (1993), S. 568-571 
    Details
    ISSN: 1432-1440
    Keywords: Intestinal lymphangiectasia ; Proteinlosing enteropathy ; Ileus
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary A 26-year-old patient presented with epigastric pain of sudden onset and severe puffy swelling of both legs and forearms. An irregularly shaped nodular filling defect on selective jejunal films, severe hypoproteinemia, low IgG concentration, and lymphopenia were suggestive of primary intestinal lymphangiectasia with protein-losing enteropathy, and the patient was placed on a low-fat diet with medium-chain triglycerides. This initially improved his condition, but some weeks later he developed obstructive ileus of the small intestine. On laparotomy yellowish to whitish deposits were found to be present in some segments of the small intestine and a fist-sized mass 100 cm distal to the duodenojejunal flexure was resected without complications. Histologically, the submucosal lymphatics were dilated, and the jejunal wall showed extensive pseudocystic, intramural submucosal lymph edema with secondary bleeding and tight stenosis of the jejunal lumen. During the 14-month follow-up time after discharge the patient has been asymptomatic and working, on no treatment other than a low-fat diet with medium-chain triglycerides.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00208483
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  • 8
    Electronic Resource
    Electronic Resource
    Mixing-models applied to industrial batch bioreactors (1993)
    Springer
    Bioprocess and biosystems engineering 9 (1993), S. 1-12 
    Details
    ISSN: 1432-0797
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Mixing models for bioreactors on the basis of the tanks-in-series concept are presented and a suitable parameter-estimation method is introduced. The Monte-Carlo-optimization procedure with the inhomogeneity-curve included in the objective function is used. Results of the parameter optimization procedure are given for stirred-tank-bioreactors equipped with one and three Rushton turbines under aerated conditions. The model designed for the stirredtank with three Rushton turbines is capable to describe the mixing properties, while in case of the stirred-tank with one Rushton turbine the simulated radial circulation time does not correlate with the measured one.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00389534
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  • 9
    Electronic Resource
    Electronic Resource
    Mathematical models for mixing in deep-jet bioreactors: Calculation of parameters (1991)
    Springer
    Bioprocess and biosystems engineering 7 (1991), S. 177-182 
    Details
    ISSN: 1432-0797
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The macroscopic mathematical model based on compartments with ideal mixing zones and tanks-in series was evaluated. Based on the experimental data obtained in a 300 dm3 pilot reactor and the dependence of mixing time on the volume of liquid phase, we have found mathematical relations between the ratio of vessel diameter to liquid level, adjustable parameters of model and the mixing time.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00387414
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  • 10
    Electronic Resource
    Electronic Resource
    Mathematical models for mixing in deep jet bioreactors: analysis (1991)
    Springer
    Bioprocess and biosystems engineering 7 (1991), S. 171-176 
    Details
    ISSN: 1432-0797
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A mathematical model for single and multi step deep-jet bioreactors is presented. A stagewise approach based on macroscopic mechanistic model which divides the reactor into compartments with good quality of mixing and plug flow regions (macromixer), was used. For the mathematical representation of this model a system of differential equations, describing the concentration of tracer in structural elements based on mass balance, and the Runge-Kutta-Fehlberg numerical method of integration, was applied. The mixing time in a 300 dm3 tank was determined by conductivity method with NaCl as tracer.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00387413
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