Bibliothek

X
feed icon rss

Ihre E-Mail wurde erfolgreich gesendet. Bitte prüfen Sie Ihren Maileingang.

Leider ist ein Fehler beim E-Mail-Versand aufgetreten. Bitte versuchen Sie es erneut.

Vorgang fortführen?

Exportieren
  • 1
    Digitale Medien
    Digitale Medien
    Linear analysis of a finite length plasma-filled backward wave oscillator (1992)
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 4 (1992), S. 1023-1032 
    Details
    ISSN: 1089-7666
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Absolute instability in a plasma-filled backward wave oscillator with sinusoidally corrugated slow wave structure driven by an intense relativistic electron beam has been analyzed numerically. The maximum spatial growth rate of the plasma-filled waveguide is found to be larger than that of an optimally designed vacuum structure. The excitation of a finite length structure is investigated. Although the spatial growth rates obtained in the linear theory increase with plasma density in the finite length plasma-filled structure for the fundamental TM01 mode of oscillation, negative global spatial growth rates prevent the coherent oscillation for intermediate ranges of plasma density, beam current, and even for structure length.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1063/1.860225
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 2
    Digitale Medien
    Digitale Medien
    The Action of Acetic Anhydride on Osazones and Hydrazones (1964)
    s.l. : American Chemical Society
    The @journal of organic chemistry 29 (1964), S. 1565-1567 
    Details
    ISSN: 1520-6904
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1021/jo01029a070
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 3
    Digitale Medien
    Digitale Medien
    A new route for the synthesis of phenazine di-N-oxides (1995)
    Springer
    Monatshefte für Chemie 126 (1995), S. 1217-1223 
    Details
    ISSN: 1434-4475
    Schlagwort(e): 2-Methyl-3-acetylquinoxaline-1,4-dioxide ; Cinnamoylquinoxaline 1,4-dioxide ; Phenazine 5,10-dioxide
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie
    Beschreibung / Inhaltsverzeichnis: Zusammenfassung Mehrere Phenazin-5,10-dioxide (7a–d) wurden durch Reaktion von 2-Methyl-3-acetylchinoxalin-1,4-dioxid (2) mit verschiedenen aromatischen Aldehyden oder durch direkte Cyclisierung der Chinoxalinderivate3 in basischem Milieuhergestellt. Zusätzlich wurden die Phenazinderivate8 und9–12 in einer Eintopfreaktion von substituierteno-Nitroanilinen mit verschiedenen Hydroxyverbindungen in Gegenwart von Natriumhypochloritlösung synthetisiert.
    Notizen: Summary Several phenazine 5,10-dioxides (7a–d) were prepared by the reaction of 2-methyl-3-acetylquinoxaline 1,4-dioxide (2) with different aromatic aldehydes or by direct cyclization of the quinoxaline cinnamoyl derivatives3 in basic medium. In addition, the phenazine derivatives8 and9–12 were synthesized by a one-pot reaction of substitutedo-nitroanilines with different hydroxy compounds in the presence of sodium hypochlorite solution.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00824300
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 4
    Digitale Medien
    Digitale Medien
    Lactate dehydrogenase and glutamate dehydrogenase activities in the circumventricular organs of rat brain following neonatal monosodium glutamate (1993)
    Springer
    Cellular and molecular life sciences 49 (1993), S. 1092-1094 
    Details
    ISSN: 1420-9071
    Schlagwort(e): Monosodium glutamate ; LDH ; GDH ; excitotoxin ; blood-brain barrier
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract Glutamate (glu) an excitatory neurotransmitter amino acid, is present in high concentrations in the mammalian central nervous system and is the most abundant amino acid in our daily diet. In the present study the activities of lactate dehydrogenase (LDH) and glutamate dehydrogenase (GDH) were evaluated in the circumventricular organs (CVO) of the brain in 25-day-old rats following MSG administration at a dose of 4 mg/g b.wt during the first ten days of life. The results show the LDH activity increased to 265% of that in the control (p〈0.001), whereas GDH activity was significantly decreased (p〈0.05), The great elevation in LDH, a cytoplasmic marker enzyme, is apparently due to cytoskeletal changes brought about as a consequence of glu toxicity, whereas lowered GDH activity indicates altered glu homostasis in the blood-brain-barrier deficient areas following neonatal exposure to glu.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01929919
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 5
    Digitale Medien
    Digitale Medien
    Ventral neural tube cells differentiate into hepatocytes in the chick embryo (1999)
    Springer
    Cellular and molecular life sciences 55 (1999), S. 128-130 
    Details
    ISSN: 1420-9071
    Schlagwort(e): Key words. Ventral neural tube cells; chick embryo; hepatocytes; development; liver.
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Medizin
    Notizen: Abstract. A population of ventral neural tube cells has recently been shown to migrate out of the hind brain neural tube via the vagus nerve and contribute to the developing gastrointestinal tract. Since liver is also innervated by the vagus nerve, we sought to determine if these cells also migrate into the liver. Ventral neural tube cells in the caudal hindbrain of chick embryos were tagged with a replication-deficient retroviral vector containing the LacZ gene on embryonic day 2. Embryos were processed for detection of labeled cells on embryonic day 5 and 11. Labeled cells were seen in the liver on both days and identified as hepatocytes. Previously, it was believed that all hepatocytes develop from the gut endoderm. Results of the present study show an additional source for the formation of liver cells.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/s000180050276
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 6
    Digitale Medien
    Digitale Medien
    Effect of neonatal monosodium glutamate on the activities of glutamate dehydrogenase and aminotransferases in the circumventricular organs of rat brain (1995)
    Springer
    Amino acids 8 (1995), S. 393-395 
    Details
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Monosodium glutamate ; Glutamate dehydrogenase ; Aminotransferases
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary Glutamate (Glu) the major amino acid in mammalian brain and most dietary proteins possesses neurotransmitter as well as neurotoxic properties. We administered monosodium glutamate (MSG) 4 mg/g bwt, sc on postnatal day (PND) 1 through 10 to rats on alternate days or daily and sacrificed them on PND 45 or PND 90 respectively. The activities of glutamate dehydrogenase and aminotransferases were evaluated in the circumventricular organs of brain. Results show that neonatal MSG produces alterations in glutamate metabolism in blood-brain-barrier deficient regions.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00806557
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 7
    Digitale Medien
    Digitale Medien
    High-Temperature Oxidation Behavior of Iron–Chromium–Aluminum Alloys (2000)
    Springer
    Oxidation of metals 54 (2000), S. 385-400 
    Details
    ISSN: 1573-4889
    Schlagwort(e): high-temperature oxidation ; Fe–Cr–Al alloys ; cyclic oxidation
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau
    Notizen: Abstract The detailed oxidation behavior of Fe–10Cr alloys, containing aluminumin the range of 2–8% by weight, was studied in pure oxygen at 1 atmpressure. The investigations were performed over the temperature range950–1050°C under cyclic conditions (3-hr cycles) in each case. Thecyclic-oxidation resistance, as measured by the specific weight-gain values,was observed to progressively improve with increasing aluminum content inthe alloy. For a particular aluminum content, however, the oxidationresistance decreased with increasing temperature. Following the initialtransient-oxidation period, a healing layer of chromia was established onthe four alloys. The lower-aluminum alloys (2–4% Al) were observedto end up with Fe-rich oxide scales under the experimental conditions atall temperatures, whereas those containing aluminum in the range of6–8% formed α-Al2O3 scales.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1004682316408
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 8
    Digitale Medien
    Digitale Medien
    The impact of three industrial effluents on submerged aquatic plants in the River Nile, Egypt (1996)
    Springer
    Hydrobiologia 340 (1996), S. 77-83 
    Details
    ISSN: 1573-5117
    Schlagwort(e): River Nile ; industrial pollution ; submerged macrophytes ; canonical ordination
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract The submerged vegetation growing in the drainage channels taking effluent from three factories (two processing sugar cane plus one producing chipboard or paper pulp; and one large fertilizer plant) into the River Nile in Upper Egypt, and in the river itself upstream and downstream of the discharge points, was studied during 1994. The main pollutants from the sugar cane factory effluents comprised organic matter, including carbohydrates; from the fertilizer plant ammonia was the principal pollutant. The study investigated the effect of these different pollutants on aquatic plant standing crop and distribution, in relation to physico-chemical characteristics of water and hydrosoil. In the effluent channels, dominated by large growths of sewage fungus, submerged vegetation was absent, although some emergent vegetation survived. In the most polluted river sites, up to 2 km downstream of discharge points, the flora was restricted to Potamogeton pectinatus L. Elsewhere in the river, a more diverse submerged flora was present, including Ceratophyllum demersum L. and Potamogeton crispus L.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF00012737
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 9
    Digitale Medien
    Digitale Medien
    Macrophyte functional variables versus species assemblages as predictors of trophic status in flowing waters (1999)
    Springer
    Hydrobiologia 415 (1999), S. 131-138 
    Details
    ISSN: 1573-5117
    Schlagwort(e): phosphate ; modelling ; eutrophication ; aquatic plants ; rivers ; irrigation channels
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie
    Notizen: Abstract A series of models was developed using functionally-derived variables (mainly based on morphological attributes of freshwater macrophytes) to predict the trophic status of river and associated channel systems. The models were compared with an existing species-assemblage based procedure for predicting British river trophic conditions (the Macrophyte Trophic Ranking scheme, MTR). We compared sites in cooler temperate conditions (in Scotland) and warmer, sub-tropical conditions (in Egypt). In total, we made measurements of 13 traits from 〉600 individual plant specimens of 33 species growing at 42 sites (divided into independent input and test site datasets). N status (as annual mean concentration in water of total oxidised nitrogen, TON) was only very poorly predicted by this approach. However, P (as annual mean concentration in water of soluble reactive phosphate, SRP) was better predicted: both by a model based on MTR (r = −0.585, p〈0.001), and by models using functional attributes of the macrophyte vegetation. River Trophic Status Indicator (RTSI) models based on ranked plant functional group relationship to river water P concentrations (RTSIFG), or field-measured trait sets of the plants (RTSITR) could also individually explain up to about 34% of the variation in P, both for the total dataset and for subsets from Egypt or Scotland alone or for high v. low-flow sites. Combining both types of RTSI measure produced the most powerful predictive model (r = 0.72, p〈0.001), explaining just over half the variability in P.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1023/A:1003833419359
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
  • 10
    Digitale Medien
    Digitale Medien
    Topographical Multilevel Single Linkage (1994)
    Springer
    Journal of global optimization 5 (1994), S. 349-358 
    Details
    ISSN: 1573-2916
    Schlagwort(e): Global optimization ; multilevel single linkage ; topographs ; graph minima
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract An iterative topographical Multilevel Single Linkage (TMSL) method has been introduced. The approach uses topographical information on the objective function, in particular theg-nearest-neighbour graph. The algorithm uses evenly distributed points from a Halten sequence of uniform limiting density. We discuss the implementation of the algorithm and compare its performance with other well-known algorithms. The new algorithm performs much better (in some cases several times) than the Multilevel Single Linkage method in terms of number of function evaluations but is not quite so competitive with respect to CPU time.
    Materialart: Digitale Medien
    URL: http://dx.doi.org/10.1007/BF01096684
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
    Artikel (Nationallizenzen)
    Volltext
Schließen ⊗
Diese Webseite nutzt Cookies und das Analyse-Tool Matomo. Weitere Informationen finden Sie hier...