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  • 1
    Electronic Resource
    Electronic Resource
    Annealing dynamics of molecular-beam epitaxial GaAs grown at 200 °C (1993)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 74 (1993), S. 306-310 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: By separating a 2-μm-thick molecular-beam-epitaxial GaAs layer grown at 200 °C from its 650-μm-thick substrate, we have been able to obtain accurate Hall-effect and conductivity data as functions of annealing temperature from 300 to 600 °C. At a measurement temperature of 300 K, analysis confirms that hopping conduction is much stronger than band conduction for all annealing temperatures. However, at higher measurement temperatures (up to 500 K), the band conduction becomes comparable, and a detailed analysis yields the donor and acceptor concentrations and the donor activation energy. Also, an independent absorption study yields the total and charged AsGa concentrations. Comparisons of all of these quantities as a function of annealing temperature TA show a new feature of the annealing dynamics, namely, that the dominant acceptor (probably VGa related) strongly decreases and then increases as TA is increased from 350 to 450 °C. Above 450 °C, ND, NA, and [AsGa] all decrease, as is known from previous studies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.354108
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  • 2
    Electronic Resource
    Electronic Resource
    Donor and acceptor concentrations in molecular beam epitaxial GaAs grown at 300 and 400 °C (1993)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 62 (1993), S. 3004-3006 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The first Hall-effect measurements on molecular beam epitaxial GaAs layers grown at the low temperatures of 300 and 400 °C are reported. Two independent methods were used to determine donor ND and acceptor NA concentrations and activation energy ED0, with the following combined results: ND(approximately-equal-to)3±1×1018, NA(approximately-equal-to)1.5±1×1017 cm−3, and ED0=0.645±0.009 eV for the 300 °C layer; ND(approximately-equal-to)2±1×1017, NA(approximately-equal-to)7±3×1016 cm−3, and ED0=0.648±0.003 eV for the 400 °C layer. Thus, the deep donor is not the expected EL2, which has ED0=0.75±0.01 eV.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.109171
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  • 3
    Electronic Resource
    Electronic Resource
    Recoil and chargin contributions to organic incorporation of radiobromine atoms following neutron activation (1972)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 76 (1972), S. 3331-3336 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100667a006
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  • 4
    Electronic Resource
    Electronic Resource
    Differences in low pH tolerance among strains of brook trout (Salvelinus fontinalis) (1976)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of fish biology 8 (1976), S. 0 
    Details
    ISSN: 1095-8649
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Survival time of brook trout (Salvelinus fontinalis Mitchill) at low pH was directly related to size, and inversely related to temperature. Between pH 2.50 and 3.25 an increase in pH by increments of 0.25 each led to a 2–3 fold increase in survival time. At higher pH's (3.25–3.75) elevations in pH by the same increments each produced a 3–5 fold increase. Brook trout tested at pH 3.35 and 3.50 showed maximum survival times in June-August. Members of seven inbred lines of brook trout were tested for acid tolerance; the lines differed markedly providing strong evidence that acid tolerance is hereditary. Tests involving either intercrossed or backcrossed offspring of tolerant or intolerant parentals demonstrated intermediate survival in 12.5% of all experiments and heterosis in 66.7% of the tests. Differences in survival of inbred lines were the most marked at pH 3.25. Exposure for 1 week at pH 3.75 resulted in a 20–25% decrease in survival time of 18 fish tested at pH 2.50 and 3.00. Out of a total of 24 trout (17 g) tested at pH 3.75 two highly tolerant individuals were still alive after 6.1 weeks. Thus it is likely that a strain resistant to a pH below 4.1, the previously recorded lower limit, can be developed by selective breeding.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1095-8649.1976.tb03901.x
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  • 5
    Electronic Resource
    Electronic Resource
    Characterization of trihalomethane (THM)-induced renal dysfunction in the rat. II: Relative potency of THMs in promoting renal dysfunction (1994)
    Springer
    Archives of environmental contamination and toxicology 27 (1994), S. 5-7 
    Details
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract Single non-lethal doses (3 mmol/kg) of chloroform (CHCl3), dichlorobromomethane (CHCl2Br), dibromochloromethane (CHClBr2), and bromoform (CHBr3) were administered by intraperitoneal injection to male Sprague-Dawley rats and proximal tubular secretion and reabsorption was assessed at varied times following treatment. Each of the trihalomethanes (THMs) at this dose inhibited proximal tubular secretion, as indicated by decreased in vitro renal cortical slice accumulation of organic anion p-aminohippuric acid (14C PAH). The time of maximal THM interference with 14C PAH uptake occurred at 8 h, with recovery being demonstrated by 48 h. Each of the THMs also demonstrated interference with tubular reabsorption, as assessed by urinary glucose excretion, with maximal interference occurring during the first day post-treatment and recovery being observed during the second day post-treatment. In each case, CHCl2Br was the most potent inhibitor of proximal tubular function. Combining these data with those of the preceding paper, the relative potency in disrupting renal function was, in general, CHCl2Br〉CHCl3〉CHClBr2〉CHBr3. Since the time course of this investigation indicates that proximal tubular dysfunction precedes other THM-induced renal function interferences, it also appears that proximal tubular damage is the primary event leading to further manifestations of renal dysfunction.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203879
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  • 6
    Electronic Resource
    Electronic Resource
    Characterization of trihalomethane (THM)-induced renal dysfunction in the rat. I: Effects of THM on glomerular filtration and renal concentrating ability (1994)
    Springer
    Archives of environmental contamination and toxicology 27 (1994), S. 1-4 
    Details
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract Single non-lethal doses (3 mmol/kg) of chloroform (CHCl3), dichlorobromomethane (CHCl2Br), dibromochloromethane (CHClBr2), and bromoform (CHBr3) were administered by intraperitoneal injection to male Sprague-Dawley rats and glomerular filtration and renal concentrating ability were assessed at varied times (5–8 h, 21–24 h, and 45–58 h) following treatment. At this dose, each of the four trihalomethanes (THMs) elevated blood urea nitrogen (BUN) and reduced renal concentrating ability (as measured by H2O intake/output ratios, urinary total osmolality, and electrolyte levels). Three of the four THMs also significantly reduced glomerular filtration rate (GFR), with only CHCl3 failing to demonstrate an effect at 3 mmol/kg. In general, CHCl2Br demonstrated the greatest interference with these renal function parameters. The times of maximal THM-induced effect on BUN and glomerular filtration rate were observed to be 24 h and 21–24 h post-treatment, respectively. These data suggest that a single acute THM treatment can inhibit mammalian renal concentrating ability and glomerular filtration.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203878
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  • 7
    Electronic Resource
    Electronic Resource
    Book review (1977)
    Springer
    Boundary layer meteorology 11 (1977), S. 521-521 
    Details
    ISSN: 1573-1472
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02185875
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  • 8
    Electronic Resource
    Electronic Resource
    Some observations from aircraft of surface albedo and the albedo and absorption of cloud (1958)
    Springer
    Theoretical and applied climatology 9 (1958), S. 28-41 
    Details
    ISSN: 1434-4483
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Description / Table of Contents: Zusammenfassung Die Albedo von Meer- und Landoberflächen sowie die Albedo und die Absorption von stabilen Wolkenschichten für Sonnenstrahlung wurden von einem Flugzeug aus gemessen, das mit nach oben und nach unten gerichteten Pyranometern ausgerüstet war. Als niedrigste, mittlere und höchste Werte, ausgedrückt als Quotient der einfallenden Strahlung, wurden gefunden: Schncebedecktes Gelände ... 0,44 0,54 0,64 Schneefreies Gelände ......... 0,11 0,15 0,25 Ozean .................................... 0,06 0,08 0,12 Wolken .................................. 0,29 0,60 0,87 Absorption der Wolken ................ 0,13 0,22 0,29 Es wird erörtert, wie sich die Strahlungsundurchlässigkeit einer Wolke von der beobachteten Variation des Strahlungsflusses mit der Wolkendicke ableiten läßt.
    Abstract: Résumé On a mesuré l'albédo de la mer et de la terre ainsi que l'albédo et l'absorption du rayonnement solaire de couches nuageuses stables dans un avion muni de pyranomètres. Les valeurs minima, moyennes et maxima exprimées en fraction du rayonnement incident sont les suivantes: sol couvert de neige ......... 0,44 0,54 0,64 sol nu ........................ 0,11 0,15 0,25 mer ........................... 0,06 0,08 0,12 nuages ........................ 0,29 0,60 0,87 absorption des nuages ....... 0,13 0,22 0,29 On montre comment la transparence d'un nuage se déduit de la variation observeé du flux de rayonnement selon l'épaisseur du nuage.
    Notes: Summary The albedo of sea and land surfaces, and the albedo and absorption of persistent layers of cloud, for solar radiation, have been measured from an aircraft fitted with upward- and downward-facing pyranometers. The lowest, mean, and highest values measured, espressed as fractions of the incident radiation, are Snow-coverer land ...... 0.44 0.54 0.64 Land ..................... 0.11 0.15 0.25 Sea ....................... 0.06 0.08 0.12 Cloud albedo ........... 0.29 0.60 0.87 Cloud absorption ...... 0.13 0.22 0.29 The derivation of the opacity of a cloud from the observed variation with depth of the radiative fluxes is discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02331001
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  • 9
    Electronic Resource
    Electronic Resource
    Absorption of solar radiation by atmospheric aerosol, as revealed by measurements at the ground (1962)
    Springer
    Theoretical and applied climatology 12 (1962), S. 19-40 
    Details
    ISSN: 1434-4483
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Description / Table of Contents: Zusammenfassung Registrierte Werte der Global- und Himmelsstrahlung am Boden bei wolkenlosem Himmel werden verglichen, mit den Werten, die für eine reine Atmosphäre unter Berücksichtigung der Rayleigh-Streuung und der Absorption durch H2O und O3 errechnet werden können. Die Himmelsstrahlung gestattet eine Abschätzung der Streuung durch das Aerosol; die Globalstrahlung gibt eine Schätzung der gesamten Schwächung. Die Absorption durch das Aerosol wird daher als Differenz der beiden Abschätzungen erhalten. Für die Aerosolstreuung wurde eine Abhängigkeit von der Streurichtung angenommen; dies wird durch Flugzeugbeobachtungen gerechtfertigt. Es werden auch die Ergebnisse aus einfachen (einmalige Streuung) und komplexen Berechnungsmethoden (mehrfache Streuung) der atmosphärischen Durchlässigkeit verglichen. In Stadtatmosphären (Kew und Wien) findet man eine Aerosolabsorption, die die von H2O übertrifft. An zwei Inselstationen (Malta und Shetland) ist die Aerosolabsorption von der gleichen Größenordnung wie die von H2O. An ausgesuchten sehr klaren Tagen wurden an drei Höhenstationen in Afrika Absorptionen von zwei bis drei Prozent gefunden, ebenso unter durchschnittlichen Bedingungen in der Antarktis. Die Untersuchung der Registrierungen der globalen Beleuchtungsstärke und der direkten Sonnenstrahlung in drei Spektralbanden in Kew ergab näherungsweise, daß dort die Gesamtschwächung und die Aerosolabsorption nicht selektiv sind. Diese Resultate sind in guter Übereinstimmung mit neueren Messungen aus Flugzeugen. Die Methode kann eine weite Anwendung finden, da jetzt Global- und Himmelsstrahlung an vielen Stationen registriert werden.
    Abstract: Résumé Les valeurs enregistrées de la radiation globale aussi bien que du ciel au sol sont comparées, dans le cas d'un ciel serein, avec les chiffres calculés pour une atmosphère pure. Dans ce second cas, on a tenu compte de la dispersion de Rayleigh et de l'absorption par H2O et O3. Le rayonnement du ciel permet d'estimer la diffusion provoquée par l'aérosol. La radiation globale permet en outre une estimation de l'extinction totale du rayonnement. L'absorption par l'aérosol est obtenue par la différence des deux estimations précédentes. On s'est servi d'une relation en fonction de la direction du rayonnement pour calculer la dispersion due à l'aérosol. Cette manière de faire semble justifiée au vu des observations d'avions. On compare en outre les résultats de la transmission de l'atmosphère obtanus par des méthodes de calculs simples (dispersion simple) ou complexes (dispersions multiples). Dans l'atmosphère des villes (Kew et Vienne), l'absorption due à l'aérosol dépasse celle de la vapeur d'eau. A deux stations placées sur des îles (Malte et les Shetlands), l'absorption due à l'aérosol est du même ordre de grandeur que celle d'H2O. On a enfin constaté, par des journées spécialement claires, des absorptions de 2 à 3 % à 3 stations de montagne en Afrique. Il en va d'ailleurs de même en conditions normales dans l'Antarctique. Le dépouillement des enregistrements de l'intensité lumineuse et de l'insolation directe dans trois bandes spectrales a montré, à Kew, que la diminution totale du rayonnement et l'absorption due à l'aérosol n'y sont à peu près pas sélectives. Ces résultats correspondent très bien à des mesures récentes faites à bord d'avions. La dite méthode peut être utilisée sur une vaste échelle vu que les radiations globale et du ciel sont enregistrées en de nombreuses stations.
    Notes: Summary Recorded values of global and diffuse solar radiation at the ground in cloudless conditions are compared with values computed for a clean atmosphere, taking into account Rayleigh scattering and absorption by H2O and O3. The diffuse radiation allows an estimate of the scattering by aerosol; the global radiation allows an estimate of the total attenuation. Aerosol absorption is thus obtained as the difference between the two estimates. An assumption of an angular distribution for aerosol scattering is involved; it is broadly justified by appeal to aircraft observations. In the course of the work comparison is made of the results of simple, single-scattering, and complex, multiple-scattering, computations of atmospheric transmission. For urban atmospheres (Kew, near London, and Vienna) aerosol absorption in excess of that due to H2O is found. For two island stations (Malta and Shetland) absorption comparable with that due to H2O is found. For selected very clear conditions at three high-level stations in Africa, and for mean conditions in the Antarctic, absorptions of two or three per cent are indicated. Examination of records of global illumination and of the direct solar radiation in three spectral bands at Kew suggests that the total attenuation and absorption by aerosol are very approximately non-selective there. These results are in broad agreement with recent direct measurements from aircraft. The method is capable of wide application, as global and diffuse solar radiation are now recorded at many stations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02317950
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  • 10
    Electronic Resource
    Electronic Resource
    Ion fluxes and diffusion potentials in the Dungeness crab,Cancer magister (1979)
    Springer
    Journal of comparative physiology 131 (1979), S. 285-292 
    Details
    ISSN: 1432-136X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Transepithelial potentials (TEP's) were measured in Dungeness crabs exposed to a variety of experimental media. The TEP's can be accounted for as diffusion potentials. In sea water (SW) theP Na/P Cl ratio (calculated by substitution in the Goldman equation) was 0.68, but in dilutions of SW the value increased, reaching a maximum of 3.33 in freshwater (FW). When the calcium and magnesium concentrations in the diluted media were maintained at SW levels theP Na/P Cl remained close to that in SW. The effluxes of Na and Cl were monitored in crabs exposed to the experimental media and the TEP's were measured simultaneously. After transfer from SW to FW the decrease in Na efflux was considerably less than expected from the change in potential alone, indicating an increased permeability to sodium, while transfer from SW to 500 mM NaCl caused a 3.4-fold increase in Na efflux without any associated change of potential. These results indicate an increase in the permeability of the gill epithelium to Na as the ambient concentrations of Ca and Mg decline. The Cl effluxes are not dependent on the external concentration of divalent ions, but about 30% of the Cl efflux may be due to exchange diffusion.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00688802
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