Library

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    Eine einfache Synthese aller vier stereoisomeren 2,2,5-Trimethyl-1,3-dioxolan-4-carbaldehyde (1994)
    Springer
    Monatshefte für Chemie 125 (1994), S. 763-771 
    Details
    ISSN: 1434-4475
    Keywords: 2,2,5-Trimethyl-1,3-dioxolane-4-carbaldehydes ; aldopentose diethyl dithioacetals ; lead tetraacetate cleavage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary A simple and efficient procedure for the syntheses of all four stereoisomers of the 2,2,5-trimethyl-1,3-dioxolane-4-carbaldehydes1a–1d has been developed. Starting with readily available aldopentose diethyl dithioacetals2,6,10 and14, the title compounds were obtained by a selective protecting group strategy and subsequentRaney-nickel reduction, followed by lead tetraacetate cleavage. This procedure allows an application on a multigram scale.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01277638
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Multiwavelength Q-switched CO2 laser with continuous discharge (1992)
    Springer
    Applied physics 55 (1992), S. 65-70 
    Details
    ISSN: 1432-0649
    Keywords: 42.60.Da ; 42.60.Fc
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract A low-pressure (20 mbar) CO2 laser allows to extract pulses at several selected wavelengths simultaneously from the same active medium. We demonstrated this, using an industrial laser modified by a Q-switch and a resonator with two branches. In one branch the wavelengths are spatially separated, whereas in the other they oscillate in one common transverse mode. We designed a multi-wavelength resonator which requires a single additional reflector compared to usual laser cavities. It provided tunable oscillation at six wavelength simultaneously.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00348616
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    3W average power 4.3 μm CO2 laser (1991)
    Springer
    Optical and quantum electronics 23 (1991), S. 405-410 
    Details
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract A 3 W average power CO2 laser oscillating in the range of 4.3μm (10°1 to 10°O transition) is described. At the same time, the laser can emit 100 W in the sequence band 00°2 to 10°1 (10.6μm). It is based on a commercial system with continuous-wave discharge of 12 m length and a slow gas flow. It operates in the Q-switched mode at pulse repetition rates up to 15 kHz. The pulse peak power is 1 kW and the pulse duration is 200 ns. The deviation from the theoretical efficiency limit has been decreased by a factor 2.5 in our device, due to saturation of the pumping (sequence band) radiation. We predict an improvement by another factor of 5 (possible average power of 10 to 20 W), if one avoids the absorption in the discharge-free zones.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00619613
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Scientific goals and experiments of the project “winter precipitation at Mount Rigi”: An overview (1993)
    Springer
    Water, air & soil pollution 68 (1993), S. 1-14 
    Details
    ISSN: 1573-2932
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering
    Notes: Abstract Wet deposition plays an important role as a mechanism for cleansing of the polluted troposphere. Fluxes of pollutants from the atmosphere to earth's surface can affect soil and aquatic ecosystems. The investigation of the pollutant incorporation into wet deposition is therefore of considerable interest for environmental research. The project “Winter precipitation at Mount Rigi” addresses the processes determining the chemical composition of wet deposition through an integrated approach considering atmospheric physical and chemical processes and their complex interactions. The investigated topics include: aerosol and gas scavenging, atmospheric chemistry (cloud water chemistry), cloud physics and dynamics. The design of the experiment, using three ground based measuring stations at the northwestern slope of the mountain, and the conceptual ideas using case study investigations are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00479389
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    IR multiphoton absorption and isotopically selective dissociation of CHCIF2 in a herriott multipass cell (1994)
    Springer
    The European physical journal 29 (1994), S. 291-298 
    Details
    ISSN: 1434-6079
    Keywords: 82.50.−m
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The small absorption is a major problem in isotopically selective IR multiphoton dissociation. Usually the radiation diverges before it is fully absorbed. To solve this problem, we have demonstrated the application of a refocusing (Herriott) multipass cell. It can generally help in laser isotope separation to use the photons more efficiently. Employing such a cell and a Q-switched CO2 laser at high repetition rate, the dissociation yield of CHCIF2 was 23 times higher than in a single pass. The number of passes used (up to 60) was more than is conventionally possible in such small cells. The increased number was permitted by making use of spherical aberration. With 18 passes, we also measured the multiphoton absorption for various wavelengths and pressures, in part separately for12CHCIF2 and13CHCIF2, and also for two-wavelength irradiation. Appropriate change of pressure or wavelength increased the absorption. But the corresponding increase of the dissociation was larger in every case. To explain this and other observations, we invoke the molecular distribution over the energy levels.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01437848
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Isotope selective dissociation of CHClF2 by a one- and two-wavelengthQ-switched CO2 laser (1992)
    Springer
    The European physical journal 24 (1992), S. 47-56 
    Details
    ISSN: 1434-6079
    Keywords: 82.50. − m
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract 13C isotope separation by multiphoton dissociation of CHClF2 was studied by a continuous-discharge CO2 laserQ-switched at 8 kHz. This laser can easily emit two or more wavelengths with good spatial and temporal overlap. The best irradiation results were obtained by the line pair 9P16 + 9P28. After optimizing also the pressures of CHClF2 and of buffer gases (He and Ar), the energy density and the gas speed, the process is now much less nonlinear than in previous experiments with a single wavelength. Differences to the TEA laser induced process were observed, and generally the pressure influence on yield and selectivity showed a variety of phenomena. They were interpreted in terms of collisional changes of spectra during the laser pulse.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01436603
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Photolithography with poly-(p-phenylene vinylene) (PPV) prepared by the precursor route (1993)
    Weinheim : Wiley-Blackwell
    Acta Polymerica 44 (1993), S. 208-210 
    Details
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/actp.1993.010440407
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...