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  1. Article: Requirements for relative intensity correction of Raman spectra obtained by column-summing charge-coupled device data.

    Hurst, Wilbur S / Choquette, Steven J / Etz, Edgar S

    Applied spectroscopy

    2007  Volume 61, Issue 7, Page(s) 694–700

    Abstract: The relative intensity correction of Raman spectra requires the measurement of a source of known relative irradiance. Raman spectrometers that employ two-dimensional charge-coupled device (CCD) array detectors may be operated in two distinct modes. One ... ...

    Abstract The relative intensity correction of Raman spectra requires the measurement of a source of known relative irradiance. Raman spectrometers that employ two-dimensional charge-coupled device (CCD) array detectors may be operated in two distinct modes. One mode directly measures the counts in each CCD pixel, but more commonly for the collection of spectra, the counts in the CCD row pixels are summed for a given column. If distortions in the corrected spectral shapes are to be avoided, operation in the mode where rows are summed places restrictions on the spatial intensity profile of the source of known irradiance that is used for the relative intensity correction procedure and, in some cases, also on the spatial intensity profile of the measured Raman light. Numerical expressions are given from which these restrictions can be derived. Magnitudes of distortions that can arise when intensity-correcting spectra obtained with CCD data where rows in a column are summed are estimated by modeling different cases. Data are given showing the inherent pixel quantum efficiency variation that exists in CCDs. Spectra are given showing the effects of a local area of significant change in pixel quantum efficiency that was found to be present on one CCD detector.
    Language English
    Publishing date 2007-07
    Publishing country United States
    Document type Journal Article
    ISSN 0003-7028
    ISSN 0003-7028
    DOI 10.1366/000370207781393235
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Optical cell for combinatorial in situ Raman spectroscopic measurements of hydrogen storage materials at high pressures and temperatures.

    Hattrick-Simpers, Jason R / Hurst, Wilbur S / Srinivasan, Sesha S / Maslar, James E

    The Review of scientific instruments

    2011  Volume 82, Issue 3, Page(s) 33103

    Abstract: An optical cell is described for high-throughput backscattering Raman spectroscopic measurements of hydrogen storage materials at pressures up to 10 MPa and temperatures up to 823 K. High throughput is obtained by employing a 60 mm diameter × 9 mm thick ... ...

    Abstract An optical cell is described for high-throughput backscattering Raman spectroscopic measurements of hydrogen storage materials at pressures up to 10 MPa and temperatures up to 823 K. High throughput is obtained by employing a 60 mm diameter × 9 mm thick sapphire window, with a corresponding 50 mm diameter unobstructed optical aperture. To reproducibly seal this relatively large window to the cell body at elevated temperatures and pressures, a gold o-ring is employed. The sample holder-to-window distance is adjustable, making this cell design compatible with optical measurement systems incorporating lenses of significantly different focal lengths, e.g., microscope objectives and single element lenses. For combinatorial investigations, up to 19 individual powder samples can be loaded into the optical cell at one time. This cell design is also compatible with thin-film samples. To demonstrate the capabilities of the cell, in situ measurements of the Ca(BH(4))(2) and nano-LiBH(4)-LiNH(2)-MgH(2) hydrogen storage systems at elevated temperatures and pressures are reported.
    Language English
    Publishing date 2011-03
    Publishing country United States
    Document type Journal Article
    ZDB-ID 209865-9
    ISSN 1089-7623 ; 0034-6748
    ISSN (online) 1089-7623
    ISSN 0034-6748
    DOI 10.1063/1.3558693
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Bonn / Germany

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  3. Article: Relative intensity correction of Raman spectrometers: NIST SRMs 2241 through 2243 for 785 nm, 532 nm, and 488 nm/514.5 nm excitation.

    Choquette, Steven J / Etz, Edgar S / Hurst, Wilbur S / Blackburn, Douglas H / Leigh, Stefan D

    Applied spectroscopy

    2007  Volume 61, Issue 2, Page(s) 117–129

    Abstract: Standard Reference Materials SRMs 2241 through 2243 are certified spectroscopic standards intended for the correction of the relative intensity of Raman spectra obtained with instruments employing laser excitation wavelengths of 785 nm, 532 nm, or 488 nm/ ...

    Abstract Standard Reference Materials SRMs 2241 through 2243 are certified spectroscopic standards intended for the correction of the relative intensity of Raman spectra obtained with instruments employing laser excitation wavelengths of 785 nm, 532 nm, or 488 nm/514.5 nm. These SRMs each consist of an optical glass that emits a broadband luminescence spectrum when illuminated with the Raman excitation laser. The shape of the luminescence spectrum is described by a polynomial expression that relates the relative spectral intensity to the Raman shift with units in wavenumber (cm(-1)). This polynomial, together with a measurement of the luminescence spectrum of the standard, can be used to determine the spectral intensity-response correction, which is unique to each Raman system. The resulting instrument intensity-response correction may then be used to obtain Raman spectra that are corrected for a number of, but not all, instrument-dependent artifacts. Peak area ratios of the intensity-corrected Raman spectrum of cyclohexane are presented as an example of a methodology to validate the spectral intensity calibration process and to illustrate variations that can occur in this measurement.
    Language English
    Publishing date 2007-02
    Publishing country United States
    Document type Journal Article
    ISSN 0003-7028
    ISSN 0003-7028
    DOI 10.1366/000370207779947585
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    Kategorien

    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

    Inter-library loan at ZB MED

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  4. Article: A Proposed Dynamic Pressure and Temperature Primary Standard.

    Rosasco, Gregory J / Bean, Vern E / Hurst, Wilbur S

    Journal of research of the National Institute of Standards and Technology

    1990  Volume 95, Issue 1, Page(s) 33–47

    Abstract: Diatomic gas molecules have a fundamental vibrational motion whose frequency is affected by pressure in a simple way. In addition, these molecules have well defined rotational energy levels whose populations provide a reliable measure of the ... ...

    Abstract Diatomic gas molecules have a fundamental vibrational motion whose frequency is affected by pressure in a simple way. In addition, these molecules have well defined rotational energy levels whose populations provide a reliable measure of the thermodynamic temperature. Since information concerning the frequency of vibration and the relative populations can be determined by laser spectroscopy, the gas molecules themselves can serve as sensors of pressure and temperature. Through measurements under static conditions, the pressure and temperature dependence of the spectra of selected molecules is now understood. As the time required for the spectroscopic measurement can be reduced to nanoseconds, the diatomic gas molecule is an excellent candidate for a dynamic pressure/temperature primary standard. The temporal response in this case will be limited by the equilibration time for the molecules to respond to changes in local thermodynamic variables. Preliminary feasibility studies suggest that by using coherent anti-Stokes Raman spectroscopy we will be able to measure dynamic pressure up to 10
    Language English
    Publishing date 1990-01
    Publishing country United States
    Document type Journal Article
    ISSN 1044-677X
    ISSN 1044-677X
    DOI 10.6028/jres.095.005
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    Order via subito

    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

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    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

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