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  • 1
    Electronic Resource
    Electronic Resource
    Synthese von kristallin-flüssigen Verbindungen. I. n-Alkyl- und n-Alkoxyderivate des 3-Hydroxy-2,5-diphenyl-pyrazins (1966)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 33 (1966), S. 265-276 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Es werden die Synthesen von 2 homologen Reihen des 3-Hydroxy-2,5-diphenyl-pyrazins und 2-Benzoyl-4(5)-phenyl-imidazols beschrieben. p-n-Alkyl- und p-n-Alkoxyphenylglyoxal-hydrate kondensieren unter ammoniakalischen Bedingungen bevorzugt zu den entsprechenden Imidazolylketonen und nur in geringen Ausbeuten zu Hydroxypyrazinen. Die Alkylhomologen des Pyrazins schmelzen ab Äthylderivat zu kristallin-flüssigen Phasen auf, die dem smektischen Typ angehören. Mit wachsenden Flügelgruppen treten Umwandlungspunkte in diesen Phasen auf. Die beiden ersten Glieder der Ätherreihe haben zusätzlich einen nematischen Bereich. Allen Imidazolylketonen fehlen diese Eigenschaften. Der Einfluß der α-ständigen Hydroxygruppe am heterocyclischen Mittelstück der gestreckten Molekeln wird diskutiert.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19660330508
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Dienoligomerisierung. XVI. Nickelkomplexkatalysierte Codimerisierung von isomeren Octatrienen mit EthenDiese Untersuchungen wurden in der Zeit von September 1973 bis Juli 1975 an der Sektion Verfahrenschemie der TH „Carl Schorlemmer“ Leuna-Merseburg durchgeführt. (1980)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 322 (1980), S. 655-662 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dienoligomerization. XVI. Catalytic Codimerization of Isomeric Octatrienes with Ethene by Nickel ComplexesThe isomeric octatrienes (n-octa-1,3c,t,7-triene 1, n-octa-1,3c,6t-triene 2 and 3-methylhepta-1,4t,6-triene 3), which are easily obtained in high yields by transition metal catalysed dimerization of butadiene, react with ethene 4 in the presence of the cationic tetrakis-(triethylphosphite)-nickelhydride complex 5 to the dodimers 3-methylnona-1,4c,t,8-triene 6, 4-vinylocta-2c, 7-diene 7, 3-methyl nona-1,4c,t,7t-triene 8, 4-vinylocta-2c,6t-diene 9, 3,6-dimethylocta-1,4c,t,7-triene 10 and 3-methyl-4-vinylhepta-1,5c-diene 11. The concentration-time dependence and a possible reaction mechanism of the codimerization are discussed and the structure data of the reaction products are reported.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19803220418
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  • 3
    Electronic Resource
    Electronic Resource
    Dienoligomerisierung. XVII. Nickelkomplexkatalysierte Codimerisierung von isomeren Octatrienen mit PropenDiese Untersuchungen wurden von September 1974 bis Juni 1975 an der Sektion Verfahrenschemie der Technischen Hochschule „Carl Schorlemmer“ Leuna-Merseburg durchgeführt. (1980)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 322 (1980), S. 663-668 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dienoligomerization. XVII. Catalytic Codimerization of Isomeric Octatrienes with Propene by Nickel-ComplexesCodimerizations of isomeric n-octa-1,3c,t,7-triene 1, n-octa-1,3c,6t-triene 2 and 3-methylhepta-1,4t,6-triene 3 with propene 4 in the presence of cationic tetrakis-(triethylphosphite)-nickelhydride complex to form 4-methyldeca-1,5t,9-triene 6, 4-isopropenylocta-2c,7-diene 10, 4-methyldeca-1,5t,8t-triene 12, 4-isopropenylocta-2c,6t-diene 16, 3,6-dimethylnona-1,4t,7c,t-trienes 17, 2,3,6,-trimethylocta-1,4t,7-triene 19 and 3-methyl-4-isopropenylhepta-1,5c-diene 22.The influence of the temperature on the reaction and a reaction mechanism is discussed.No codimers from octatrienes and isobutene were formed under the conditions of this work.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19803220419
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  • 4
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    High-sensitivity receiver for infrared laser communications. (1972)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: Description of a high-sensitivity wide-bandwidth 10.6-micron heterodyne receiver for space and ground operational use. The receiver includes a cooled HgCdTe infrared mixer diode, a conical scanner for spatial tracking, an acquisition channel for spatial search and station alignment, and an automatic frequency-control channel to maintain a fixed laser frequency offset. The infrared mixer is designed to provide nearly quantum-noise-limited operation over an extended range of mixer temperature, bias voltage, and intermediate frequency. The resultant experimental receiver has a measured noise equivalent power of less than 10 to the minus 19th W/Hz over the 15- to 40-MHz i.f. band for mixer temperatures from 85 to 115 K, and less than 2 x 10 to the minus 19th W/Hz up to 140 K. Mixer 3-dB cutoff frequencies as high as 420 MHz were measured at a mixer temperature of 125 K. An analysis and engineering equations are given for receiver noise components, noise equivalent power, available mixer conversion gain, mixer transducer gain, and quantum-noise factor in terms of such factors as mixer parameters, quantum efficiency, mixer temperature, dynamic conductance, bias voltage, local oscillator power, and i.f. amplifier characteristics.
    Keywords: COMMUNICATIONS
    Format: text
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    NASA TECHNICAL REPORTS
  • 5
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    Coherent infrared receivers for laser communications and radar. (1971)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Review of infrared coherent detection processes. Three receivers are described which were built with the primary goal of exploiting quantum noise limited heterodyne detection in a spectral region where atmospheric transmission characteristics are favorable. The combination of high power, high efficiency carbon dioxide lasers, coherent heterodyne receivers with sensitivities approaching the quantum noise limit, and low-loss atmospheric transmission have presented new possibilities in infrared communications and radar. In particular, high sensitivity 10.6 micrometer heterodyne receivers with wide IF bandwidths have been developed.
    Keywords: COMMUNICATIONS
    Type: Electro-Optical Systems Design Conference; Sep 14, 1971 - Sep 16, 1971; New York, NY
    Format: text
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    NASA TECHNICAL REPORTS
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