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  • SPACE RADIATION  (3)
  • Geometric and positional isomer separations  (1)
  • INSTRUMENTATION AND PHOTOGRAPHY  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Separation of positional isomers on polymeric calix[4]arene-siloxane stationary phases in capillary GC (1998)
    Springer
    Chromatographia 48 (1998), S. 422-426 
    Details
    ISSN: 1612-1112
    Keywords: Gas chromatography ; Calix[4]arene-tetramethyldisiloxane stationary phases ; Geometric and positional isomer separations
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Poly(p-tert-butyldimethoxydipropyloxycalix[4]arene-tetramethyldisiloxane) (TBCX-TMDS) and poly(dimethoxydipropyloxycalix[4]arene-tetramethyl-disiloxane) (CX-TMDS), have been prepared and used as stationary phases for isothermal capillary gas chromatographic separations of positional isomers. Retention factors and separation factors for the isomers were measured. The isomers investigated were well-resolved on the two phases. Retention of all the solutes investigated is greater on TBCX-TMDS than on CX-TMDS, probably because of extra dispersive interactions of the solutes with thetert-butyl groups of the phase. Separation factors for closely-eluting isomer pairs are similar on the two phases. This seems to indicate either that the solutes are retained by non-inclusion processes or that if the isomer molecules do enter the cavity of the calixarene, i.e. the solute is retained by inclusion, thetert-butyl groups do not play a role in discriminating between the isomers.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02467714
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    Paper (German National Licenses)
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  • 2
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    Cosmic diffuse gamma rays from 2 to 25 MeV (1977)
    In:  Other Sources
    Details
    Publication Date: 2019-06-27
    Description: Results are reported for measurements of cosmic diffuse gamma rays performed with a double Compton scatter gamma-ray telescope flows aboard a balloon at 3.5-g/sq cm residual atmosphere. The operation and calibration of the telescope are briefly reviewed, unwanted backgrounds are identified, and the only significant background for the telescope used is shown to arise from the interaction of albedo neutrons with hydrogen and carbon in one of the liquid scintillators. The fluxes of cosmic diffuse gamma rays with energies of 2 to 3, 3 to 5, 5 to 7, 7.5 to 10 MeV are listed, and upper limits are provided for energies of 10 to 15 and 15 to 25 MeV. These data are compared with numerous previous measurements, and no indication is found that the diffuse radiation is statistically different from isotropic. Upper limits are placed on the gamma-ray fluxes (mainly 3 to 25 MeV) from various localized sources.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; vol. 218
    Format: text
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    NASA TECHNICAL REPORTS
  • 3
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    Large area double scattering telescope for balloon-borne studies of neutrons and gamma rays (1975)
    In:  Other Sources
    Details
    Publication Date: 2019-06-27
    Description: A large area double scattering telescope for balloon-borne research is described. It measures the flux, energy and direction of 2-100 MeV neutrons and 0.5-30 MeV gamma rays. These measurements are made using time-of-flight and pulse height analysis techniques with two large tanks of mineral oil liquid scintillator. Results from Monte Carlo calculations of the efficiency, energy resolution and angular resolution are presented and the electronics implementation for the processing of 80 photomultiplier tubes signals will be discussed. The detector weighs 800 kg with a large part of this weight being the liquid scintillator (320 kg). It will be flown at 3 mbars for flight durations up to 40 hours. The first flight is planned for Spring, 1975.
    Keywords: INSTRUMENTATION AND PHOTOGRAPHY
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    NASA TECHNICAL REPORTS
  • 4
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    Cosmic diffuse gamma-rays at medium energies (1978)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Cosmic diffuse gamma-ray fluxes have been measured in six energy intervals from 2 to 25 MeV with a balloon-borne gamma-ray telescope. It is found that the observed fluxes are compatible with an energy distribution of 0.0265 times E to the -2.08 (photon/sq cm-s-sr-MeV) at lower energies and steepen at higher energies to meet a power law of 0.017 (E/MeV) to the -2.4. No deviation of the gamma-ray flux from isotropy is observed for five different times during the balloon flight for 10-deg intervals up to 50 deg from the zenith and at celestial coordinates varying from latitude -27 deg, longitude 102 deg to latitude 56 deg, longitude 195 deg, excluding the region in the galactic-anticenter direction. Upper limits to fluxes of 3-25-MeV gamma rays are deduced for a number of possible galactic and extragalactic sources.
    Keywords: SPACE RADIATION
    Type: International Cosmic Ray Conference; Aug 13, 1977 - Aug 26, 1977; Plovdiv; Bulgaria
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  • 5
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    Gamma-rays of 3 to 25 MeV from the galactic anti-center and pulsar NP 0532 (1978)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Gamma-rays of 3 to 25 MeV are reported from the galactic anticenter region and the Crab Pulsar, NP 0532. The observations were carried out from Palestine, Texas, on May 13, 1975. Gamma-rays from the galactic anticenter were observed as the Crab Nebula passed overhead within 10 deg of the zenith. Pulsed gamma-rays from NP 0532 were observed at a 4.4-sigma significance level. The total flux from 3-25 MeV is 0.0049 + or - 0.002 photon/sq cm-sec. The pulsed flux from NP 0532 from 3 to 25 MeV is 0.00043 + or - 0.00026 photon/sq cm-sec. The ratio of the total to the pulsed flux from 3 to 25 MeV is 11 + or - 8.
    Keywords: SPACE RADIATION
    Type: International Cosmic Ray Conference; Aug 13, 1977 - Aug 26, 1977; Plovdiv; Bulgaria
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    NASA TECHNICAL REPORTS
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