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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 89 (2001), S. 973-979 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The energy relaxation rate for hot electrons in n-type GaN epilayers has been measured over the temperature range 1.5–300 K. Several samples grown by molecular-beam epitaxy and having different electron concentrations have been studied. At low electron temperatures (Te〈20 K), the energy relaxation is via acoustic phonon emission. The magnitude and temperature dependence of the energy relaxation are found to be in good agreement with theoretical calculations using appropriate values of the deformation potential and piezoelectric coupling constants and ignoring screening. For Te≥70 K, the dominant mechanism of energy loss is optic phonon emission. For the several samples studied, consistent values of the optic phonon energy and electron-optic phonon relaxation time, 90±4 meV and 5–10 fs, respectively, are measured. The energy agrees well with values obtained by other methods and the relaxation time is consistent with theoretical calculations of the Fröhlich interaction and indicate that hot phonon effects are absent up to 10−8 W/electron dissipation. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 77 (2000), S. 3209-3211 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have used pulse time-of-flight techniques to examine the phonon emission from an optically excited GaAs/AlAs superlattice structure. For laser excitation wavelengths shorter than 767 nm (the energy of E1HH1 transition), we detect a significant longitudinal acoustic phonon component directed in a narrow beam normal to the structure. Under identical excitation conditions, generation of coherent longitudinal acoustic phonons has previously been observed in this structure. We suggest that the excitation wavelength and angular characteristics of the longitudinal acoustic emission is consistent with those of propagating modes produced as coherent phonons "leak" from the superlattice structure. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 75 (1999), S. 3832-3834 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We have used bolometric detection to observe directly the phonons emitted by photoexcited carriers in the InAs/GaAs self-organized quantum-dot system. We find that about 74% of the energy lost by carriers in the InAs dots and wetting layer is via emission of low-frequency acoustic phonons and argue that this is facilitated by Auger scattering. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Water and environment journal 7 (1993), S. 0 
    ISSN: 1747-6593
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: The River Slea through Sleaford is fed by groundwater emanating from the Lincolnshire Limestone. In recent years, the springs have dried up periodically, causing failure of river flow through the town. The Slea is a main feature of the town and, when flowing, a valuable visual amenity. Conversely, when it is not flowing, progressive water quality deterioration in ponded sections reduces the river corridor to an eyesore. The paper describes investigations into the cause of the problem and how to overcome it.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Water and environment journal 5 (1991), S. 0 
    ISSN: 1747-6593
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: The Avalon Lakes project was a concept to utilize, as water storage reservoirs, shallow basins left by commercial peat exploitation. There are, however, important nature-conservation interests in the project area. The proposed scheme ultimately incorporated measures to enhance these and, perhaps unusually for a source development, was broadly supported by conservation groups. The related cost was estimated at £4.2M, or 17% of the overall source works’price.Plans and scientific investigations of the scheme occupied a span of 21 years to 1988. It was eventually abandoned as an option for future water supplies following the restructuring of Wessex Water Authority in preparation for privatization of the water industry. The grounds for terminating the project were substantially concerned with costs, though coloured by lingering apprehension about the consistency of water quality.There is now a greater public awareness of the adverse environmental effects of water resource developments. It is suggested that this will lead to future schemes, less obviously suited to their surroundings than Avalon, incurring a higher conservation-related cost in order to gain acceptance.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Water and environment journal 2 (1988), S. 0 
    ISSN: 1747-6593
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: The risks and severity of pollution events affecting surface waters have to be assessed from an inventory of pollution threats in each catchment, from regional and national statistics on pollution incidents, and from measurements on the travel and dispersal of pollutants in water courses. Inspection of factory premises, farms, and sewage treatment works commonly reveals ways of stopping potential sources of pollution. Other countermeasures include: bunding of chemical stores and handling areas; processing waste liquors on site; promptly notifying tanker accidents and other spills; broad band monitoring of river water quality; control of intake, buffer storage and water treatment, in light of pollution arrival and chemical data.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0039-6028
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Solid State Electronics 32 (1989), S. 1755-1759 
    ISSN: 0038-1101
    Keywords: GaAs heterojunctions ; Heat pulses ; Magnetophonon resonance ; Optical phonon decay ; Phonon emission
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    World journal of surgery 10 (1986), S. 814-818 
    ISSN: 1432-2323
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé De janvier 1971 à décembre 1984, 53 malades atteints d'une colite aiguë grave caractérisée cliniquement par une température à 38°, un pouls supérieur a 100/mm et plus de 5 selles diarrhéiques sanglantes quotidiennes ont été traités. Vingt-huit (dont 12 hommes) présentaient une colite ulcéreuse et 25 (dont 13 hommes) une maladie de Crohn. La crise grave se manifesta plus tôt au cours de la maladie chez les malades atteints de maladie de Crohn. L'âge moyen pour le Crohn fut de 31 ans (17–58) et de 41 ans (17–70) pour la colite ulcéreuse. Tous les malades furent traités dans une unité gastroentérologique médicale et chirurgicale. Le traitement initial fut médical: 49 malades recurent des corticoïdes, 39 de la salazopyrine et 8 des antibiotiques. Vingt-sept malades répondirent favorablement au traitement médical en 11 jours en moyenne (3 à 30). Trois d'entre eux durent être opérés ultérieurement. Vingt-six malades durent être opérés en urgence (coloprotectomie totale: 9, colectomie totale avec anastomose iléorectale: 11, colectomie avec conservation du rectum: 6). Chez 10 malades se développa un mégacolon toxique, 9 devant être opérés d'urgence. Les autres initialement stabilisés furent colectomisés au cours de leur hospitalisation. Aucun décès ne fut à déplorer. Les complications postopératoires furent rares. Au moment de l'admission aucun facteur ne permettait de prédire la nécessité d'une intervention. Les auteurs ont la conviction que la collaboration étroite entre médecins et chirurgiens permet d'éviter la morbidité et la mortalité de la colite fulminante.
    Abstract: Resumen Desde enero de 1971 hasta diciembre de 1984 tuvimos 53 pacientes con colitis aguda severa, a juzgar por temperatura de 38°C., pulso mayor de 100/min y diarrea sanguinolenta de más de 5 veces/día. Veintiocho pacientes (12 hombres) presentaban colitis ulcerativa y 25 (13 hombres) colitis de Crohn. El ataque grave ocurrió en las fases tempranas de la evolución de la enfermedad en los pacientes con colitis de Crohn. En los pacientes con enfermedad de Crohn, la edad promedio fue 31 años (rango 17–58) y en los pacientes con colitis ulcerativa, fue 41 años (rango 17–70). Todos los pacientes fueron manejados en una unidad gastroenterológica médica y quirúrgica combinada. El tratamiento inicial fue médico; 49 pacientes recibieron corticoesteroides, 39 salazoprina y 8 antibiótico. Veintisiete pacientes se estabilizaron bajo tratamiento médico en un promedio de 11 días (rango 3–30). De ellos, 3 requirieron resección posteriormente. Veintiseis pacientes requirieron operación urgente (panproctocolectomía en 9, colectomía total y anastomosis ileorectal en 11 y colectomía con conservación del recto en 6). Diez pacientes desarrollaron megacolon tóxico, y 9 requirieron cirugía urgente. El otro se estabilizó inicialmente, pero fue sometido a colectomía más tarde durante la misma admisión. No hubo muertes en esta série, y las complicaciones operatorias fueron poco frecuentes. En la admisión no se logró identificar factores que pudieran predecir la necesidad de operación. Creemos que mediante una estrecha colaboración entre internistas y cirujanos se puede evitar la mortalidad y morbilidad de colitis severa y fulminante.
    Notes: Abstract From January 1971 to December 1984, fifty-three patients presented with severe acute colitis, defined clinically as a temperature above 38°C., a pulse above 100/min, and bloody diarrhea more than 5 times/day. Twenty-eight patients (12 male) had ulcerative colitis, 25 patients (13 male) had Crohn's colitis. The severe attack occurred earlier in the course of the disease in Crohn's colitis. The mean age for those with Crohn's disease was 31 years (range 17–58) and 41 years (range 17–70) for those with ulcerative colitis. All patients were managed on a combined medical and surgical gastrointestinal unit. The initial treatment was medical; 49 patients received corticosteroids, 40 salazopyrine, and 7 antibiotics. Twenty-seven patients settled on medical treatment in a mean of 11 days (range 3–30). Of these, 3 required resection later. Twenty-six patients required urgent operation (panproctocolectomy in 9, total colectomy and ileorectal anastomosis in 11, and colectomy with retention of rectum in 6). Ten patients developed toxic megacolon, 9 requiring urgent surgery. The other one initially settled but had a colectomy later on during the admission. There were no deaths in this series. Postoperative complications were uncommon. No factors on admission could predict the need for an operation. We believe that with close cooperation between experienced physicians and surgeons, mortality and morbidity from severe, fulminating colitis can be avoided.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Amsterdam : Elsevier
    Physica B: Physics of Condensed Matter 194-196 (1994), S. 419-420 
    ISSN: 0921-4526
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
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