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  • 1
    Electronic Resource
    Electronic Resource
    Performance evaluation — Test configurations and results (1996)
    Springer
    Telecommunication systems 5 (1996), S. 249-272 
    Details
    ISSN: 1572-9451
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract In this paper experimental designs for investigating performance parameters and their corresponding experimental results on the EXPLOIT testbed facilities are given. In an exemplary way the performance evaluation of a switch and an ATM network is described. These designs and results can be used in two ways: firstly in determining the network performance of already existing equipment and networks and secondly in designing new equipment by modelling the described scenarios within simulations. As important network performance parameters under study have been identified cell delay, cell loss and cell delay variation. These will be investigated together with some techniques for assessing those. Initially the question, whether the occurring delays in successive switches are independent, is tackled. If the independence assumption holds true or the correlation can be quantified, then out of measurements at a single switch the delay behaviour after having passed a number of switches can be determined, thus extrapolation from a small network to a larger one becomes possible. Afterwards the fairness of the switch design with respect to multiplexing traffic sources while being in an overload state are discussed. For being able to predict delays in the future the suitability of “traditional” queueing models will be checked. Out of this, forecasts on cell losses can be gained as well. For this investigation specific traffic mixes have been chosen, which are representative of the predicted traffic for future ATM networks. Also some results on the end-to-end cell delay variation are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02109737
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  • 2
    Electronic Resource
    Electronic Resource
    Reaktionen der Methylencyclopropane, VII. Nickel(0)-katalysierte Cycloadditionen von Methylencyclopropanen mit Acrylsäure-alkylestern (1983)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 2920-2930 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Methylenecyclopropanes, VII. Nickel(0)-catalysed Cycloadditions of Methylenecyclopropanes with Alkyl AcrylatesCycloaddition reactions of methylenecyclopropane (1) and of the ring-methylated methylene-cyclopropanes 5, 9 and 12 with alkyl acrylates are performed at nickel(0) catalysts, such as bis(1,5-cyclooctadiene)nickel unter mild conditions (0-50°C). Depending on the degree of methylation of the three-membered ring, 1 and 5 give only alkyl 3-methylenecyclopentane-carboxylates (4 and 6), whereas 9 leads to a mixture of the methylenecyclopentane derivative 10 and the alkyl spiro[2.3]hexanecarboxylate 11, and 12 react to form only the spiro[2.3]hexane derivative 13. With 12 isomerisation to 2,3,3-trimethyl-1,4-pentadiene (15) also takes place. In the case of 9 the ratio of methylenecyclopentane to spiro[2.3]hexanecarboxylate can be influenced by the size of alkyl groups. - In the Ni0-catalysed reactions of 1 with substituted acrylates (methyl crotonate or diethyl maleate) codimerisation to 16 and 17 competes with cyclodimerisation to 2 and 3.
    Notes: An Nickel(0)-Katalysatoren, bevorzugt Bis(1,5-cyclooctadien)nickel, gelingen Cycloadditionen von Methylencyclopropan (1) und dessen am Ring methylierten Derivaten 5, 9 und 12 mit Acrylsäure-alkylestern unter milden Bedingungen (0-50°C). In Abhängigkeit von dem Methylierungsgrad des Dreirings entstehen aus 1 und 5 nur 3-Methylencyclopentancarbonsäure-alkylester (4 bzw. 6), aus 9 Gemische dieser Methylencyclopentan-Derivate (10) mit einem Spiro[2.3]hexancarbonsäure-alkylester (11) oder aus 12 nur das Spiro[2.3]hexanderivat 13. Mit 12 tritt auch Isomerisierung zu 2,3,3-Trimethyl-1,4-pentadien (15) ein, Bei 9 kann das Methylencyclopentan-/Spiro[2.3]-hexancarbonsäureester-Verhältnis durch die Größe des Alkylrestes im Acryl beeinflußt werden. - Dagegen konkurrieren bei den Ni0-katalysierten Reaktionen von 1 mit substituierten Acrylsäureestern (Crotonsäure-methylester, Maleinsäure-diethylester) Cyclodimerisierung zu 2 und 3 mit der Codimerisierung zu 16 und 17.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19831160819
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  • 3
    Electronic Resource
    Electronic Resource
    Reaktionen der Cyclopropene, VII. Nickel(0)-katalysierte Cotrimerisierungen von 3,3-Dimethylcyclopropen mit Methylacrylat (1986)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 119 (1986), S. 3089-3101 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Cyclopropenes, VII. Nickel(0)-catalyzed Cotrimerisation of 3,3-Dimethylcyclopropene with Methyl AcrylateThe cotrimerisation of 3,3-dimethylcyclopropene (1) with methyl acrylate is catalyzed by phosphane- or phosphite-Ni(0) compounds under mild conditions (40-50°C). Depending on the nature of the phosphane or phosphite 1 and methyl acrylate cotrimerise mainly in the ratio 2:1 or 1:2 to give cis/trans-5 or cis/trans-6 and cyclic cis/trans-7. trans-5 and trans-6 are thermally more labile than the corresponding cis compounds. Heating to 200°C for two hours induces their complete rearrangement to 12 and 13 or 14 via 1,5-homodienyl-hydrogen shift.
    Notes: Triorganylphosphan- und -phosphit-haltige Nickel(0)-Verbindungen katalysieren die Cotrimerisierung von 3,3-Dimethylcyclopropen (1) mit Methylacrylat unter milden Bedingungen (40-50°C). In Abhängigkeit von der Art des Phosphans bzw. Phosphits entstehen bevorzugt offenkettige Cotrimere aus einem Mol 1 und zwei Mol Methylacrylat (cis/trans-5) oder offenkettige und cyclische Cotrimere aus zwei Mol 1 und einem Mol Methylacrylat (cis/trans-6 und cis/trans-7). trans-5 und trans-6 sind thermisch deutlich labiler als die entsprechenden cis-Derivate. Im Zuge einer 1,5-Homodienylwasserstoffwanderung lagern sie sich bereits nach zweistündigem Erhitzen auf 200°C quantitativ in die entsprechenden 1,4-Diene um (12 und 13 aus trans-5 bzw. 14 aus trans-6).
    Additional Material: 7 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19861191016
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  • 4
    Electronic Resource
    Electronic Resource
    Cyclische Ketone aus 3,3-Dimethyl-1-cyclopropen und Kohlenmonoxid durch katalysierte Cotrimerisation (1978)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 111 (1978), S. 2689-2695 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Cyclic Ketones from 3,3-Dimethyl-1-cyclopropene and Carbon Monoxide by Catalyzed CotrimerisationThe tetracarbonylnickel-catalyzed cotrimerisation of 3,3-dimethyl-1-cyclopropene (1) and carbon monoxide gives 3,3,7,7-tetramethyl-trans-tricyclo[4.1.0.02,4]heptan-5-one (5) and 2-isopropyl-6,6-dimethylbicyclo[3.1.0]hex-2-en-4-one (6). Further products are the cyclodimer 2 and the cyclotrimers 3 and 4. - Tetracarbonylnickel is a poor catalyst for the codimerisation of 1 with methyl acrylate and methyl trans-crotonate.
    Notes: Tetracarbonylnickel katalysiert die Cotrimerisation von 3,3-Dimethyl-1-cyclopropen (1) und Kohlenmonoxid zu 3,3,7,7-Tetramethyl-trans-tricyclo[4.1.0.02,4]heptan-5-on (5) und 2-Isopropyl-6,6-dimethylbicyclo[3.1.0]hex-2-en-4-on (6). Außerdem entstehen aus 1 das Cyclodimere 2 sowie die Cyclotrimeren 3 und 4. - Eine Codimerisation von 1 mit Acrylsäure- sowie trans-Crotonsäure-methylester an Tetracarbonylnickel gelingt praktisch nicht.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19781110723
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  • 5
    Electronic Resource
    Electronic Resource
    Reaktionen des Methylencyclopropans, II. Katalytische Trimerisation des Methylencyclopropans an mit Trialkylphosphin modifizierten Nickel(0)-Verbindungen (1977)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1977 (1977), S. 1065-1079 
    Details
    ISSN: 0075-4617
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reactions of Methylenecyclopropane, II). - Catalytic Trimerisation of Methylenecyclopropane at Nickel(0) Compounds Modified by TrialkylphosphinesThe catalytic trimerisation of methylenecyclopropane (1) using nickel(0) compounds modified by trialkylphosphines gives mixtures of three open-chained (5, 6, 7) and three cyclic (8, 9, 10) C12H18-isomers, in up to 95% yield. Cyclodimers (2, 3) and higher oligomers are formed as by-products. The ratio of trimers depends on the nature of the alkyl group attached to the phosphorus; e. g. only 5 and 6 are formed with triethylphosphine or triphenylphosphine, whereas tert-butyl(diisopropyl)phosphine or di-tert-butyl(isopropyl) phosphine gives 8 in up to 55% yield. - The new hydrocarbons 5 - 10 are characterised with the aid of their IR, MS, and 1H-NMR spectra. The possible modes of formation are discussed.
    Notes: Methylencyclopropan (1) trimerisiert an mit Trialkylphosphin modifizierten Nickel(0)- Verbindungen katalytisch in bis zu 95 proz. Ausbeute zu einem Gemisch von drei offenkettigen (5, 6, 7) und drei cyclischen (8, 9, 10) C12H18-Isomeren. Nebenprodukte sind Cyclodimere (2,3) sowie höhere Oligomere. Das Mengenverhältnis der Trimeren läßt sich durch die Art der Alkylreste am Phosphin beeinflussen: Mit Triethylphosphin oder Triphenylphosphin bilden sich nur 5 und 6, mit tert-Butyl(diisopropyl)phosphin oder Di-tert-butyl-(isopropyl)phosphin bis zu ca. 55% 8. - Die neuen Kohlenwasserstoffe 5 - 10 werden mit Hilfe der IR-, MS- und 1H-NMR-Spektren identifiziert. Die möglichen Bildungswege werden erörtert.
    Additional Material: 8 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.197719770702
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  • 6
    Electronic Resource
    Electronic Resource
    Reaktionen der Methylencyclopropane, XI Asymmetrische Nickel(0)-katalysierte [3 + 2]-Cycloadditionen von Methylencyclopropanen mit chiralen Acrylsäure-Derivaten (1989)
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1989 (1989), S. 739-750 
    Details
    ISSN: 0170-2041
    Keywords: Asymmetric induction ; Chiral acrylic acid derivatives ; Chiral 3-methylenecyclopentane derivatives ; [3+2] Cycloadditions, Ni(0)-catalyzed ; Methylenecyclopropanes ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Methylenecyclopropanes, XI. - Asymmetric Nickel(0)-Catalyzed [3+2] Cycloadditions of Methylenecyclopropanes with Chiral Derivatives of Acrylic AcidThe nickel(0)-catalyzed codimerisation of methylenecyclclopropane 1a or 2,2-dimethylmethylenecyclopropane (1b) with the chiral derivatives of acrylic acid 2a-2f leads to the optically active 3-methylenecyclopentanecarboxylic esters 3a, 3c-3f, 4a, and 4c, or amides 3b and 4b in good yields. The diastereomeric excess accessible depends on the steric demand of the chiral auxiliaries, de values up to 98% can be achieved. Some improvements of the preparation of optically pure auxiliaries are also decribed.
    Notes: Bei der Nickel(0)-katalysierten Codimerisierung von Methylencyclopropan (1a) oder 2,2-Dimethylmethylencyclopropan (1b) mit den chiralen Acrylsäure-Derivaten 2a-2f werden die 3-Methylencyclopentancarbonsäureester bzw. -amide (3a-3f, 4a-4c) in guten Ausbeuten gewonnen, wobei, in Abhängigkeit von den sterischen Gegebenheiten der chiralen Hilfsstoffe, Diastereomerenüberschüsse bis zu 98% de erzielt werden. Einige Verbesserungen in der Darstellung der optisch reinen Hilfsgruppen werden ebenfalls beschrieben.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jlac.198919890222
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  • 7
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    Iridium-Catalyzed Enantioselective Hydrogenation of Imines in Supercritical Carbon Dioxide (1999)
    American Chemical Society
    Details
    Publication Date: 1999-07-01
    Print ISSN: 0002-7863
    Electronic ISSN: 1520-5126
    Topics: Chemistry and Pharmacology
    Published by American Chemical Society
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  • 8
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    Asymmetische Induktion bei der Nickel(0)-katalysierten [3+2]-cycloaddition von Methylencyclopropan mit chiralen Alkylacrylaten (1983)
    Elsevier
    Details
    Publication Date: 1983-01-01
    Print ISSN: 0040-4039
    Electronic ISSN: 1873-3581
    Topics: Chemistry and Pharmacology
    Published by Elsevier
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  • 9
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    Mechanistic aspects of dihydrogen activation and transfer during asymmetric hydrogenation in supercritical carbon dioxide (2000)
    Wiley
    Details
    Publication Date: 2000-01-01
    Print ISSN: 0899-0042
    Electronic ISSN: 1520-636X
    Topics: Chemistry and Pharmacology
    Published by Wiley
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