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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 80 (1996), S. 6148-6154 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A study of the temporal response of a biased Fabry–Perot etalon with a nematic liquid crystal exposed to short (∼10 μs) voltage pulses is presented. It is found that the finesse is the crucial factor determining the achievable switching time. For a given maximum transmission the reflectivities of the Fabry–Perot mirrors are optimized to achieve minimum switching times. In particular, switching times of 0.5 μs with an initial transmission of 3% and a maximum value of 70% have been obtained. The experimental results are in good agreement with theory. © 1996 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 78 (1995), S. 3020-3025 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: A study of the temporal response of a biased planar nematic liquid crystal to short (∼10 μs) voltage pulses is presented. The resulting optical phase shift varies quadratically with time during the first 2 μs after switching the voltage on and then linearly. A theoretical model is developped starting from the Leslie-Ericksen theory which describes the investigated phase modulation in the microsecond time scale. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 109 (1998), S. 4224-4236 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The reaction of the cyano radical (CN) with hydrogen was studied by time-resolved infrared absorption spectroscopy of individual rovibrational states of HCN. The initial vibrational level distribution of HCN(v10v3) was determined by plotting the time dependence of the fractional population of a vibrational level and extrapolating these curves to the origin of time. The experiments were carried out at two temperatures, 293 and 324 K, with similar results. It was estimated that about 50% of the available reaction exothermicity was deposited as vibrational excitation of the HCN product. Surprisingly, the HCN(101) vibrational level received a significant fraction of the observed vibrational population, implying that the CN vibration was not really a spectator bond in the reaction dynamics. Furthermore, the observed HCN(v10v3) vibrations only account for about 27% of the initial HCN population produced in the title reaction. A significant fraction of the product HCN molecules must have been produced with the bending mode excited, likely in combination with the H–C stretch vibrations. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The integrated-absorption coefficients of several hyperfine lines of the magnetic dipole allowed transition of the bromine atom, Br, center at 3685.2 cm−1 were measured, and a value for the square of the magnetic dipole transition moment of the Br atom was determined. A theoretical calculation for the magnetic dipole transition moment was also carried out using a relativistic ab initio atomic structure formulation. The theoretical value was in excellent agreement with the value predicted assuming pure LS coupling, and in reasonable agreement with experiment. The Br atom was generated in equal concentration with the cyano radical (CN) by the 193 nm photolysis of cyanogen bromine, BrCN. The CN radicals were titrated by the rapid reaction with C3H8 to generate HCN and a small amount of HNC. Both time-resolved and frequency-scanned infrared absorption spectroscopy were used to monitor the Br, HCN, and HNC species. The photolysis of BrCN at 193 nm produced both the ground state Br(2P3/2) and the spin-orbit excited Br(2P1/2) atoms, and the yield for the production of Br(2P1/2) atoms was measured to be 0.31±0.01. The rate constants for the quenching of Br(2P1/2) by BrCN and C3H8 at 293 K were also determined. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 109 (1998), S. 6312-6319 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The square of the electronic–vibrational transition moment for the (2,0) band of the cyano radical (CN), A 2Π←X 2Σ+, red system at 789.5 nm has been determined using a direct time-resolved absorption technique. The line strength of the R1(8.5) transition of 12C14N was measured by comparison to the known line strength of the H12C14N(001)←(000) P(8) infrared υ3 fundamental transition near 3.05 μm. The CN radical was created by pulsed-laser photolysis of cyanogen, (CN)2, in a mixture of H2 and (CN)2 in either Ar or He carrier gas at 293 K. Both CN and HCN were monitored by time-resolved absorption spectroscopy during the same photolysis laser pulse. A simple kinetic model was used to relate the two absorption features to each other. The square of the electronic–vibrational transition moment for the A←X(2,0) band was found to be 7.8±1.0×10−38 esu2 cm2 in good agreement with theoretical calculations based on ab initio quantum chemistry methods. © 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 102 (1995), S. 7966-7982 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The reaction of the cyano radical (CN) with ethane was studied using time-resolved infrared absorption spectroscopy to monitor individual rovibrational states of the HCN product. A method is described that can be used to determine the initial vibrational state distribution at pressures of several Torr. This technique was applied to the title reaction to determine that the vibrational states of HCN(v1,0,v3), where v1, v3=0, 1, and 2, were not directly populated in the title reaction to any significant extent. The initial vibrational energy content of the CN radical was also varied but did not influence the initial population in the HCN vibrational levels probed in this experiment. The time dependence of HCN(v1,0,v3) was followed and interpreted in terms of bimolecular rate constants for vibrational relaxation with ethane. The title reaction is mode specific in its energy disposal in that at least every HCN product appears to have at least one quantum of bending excitation, likely in combination with stretching vibrations. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 103 (1995), S. 2863-2872 
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A direct measurement of the transition dipole moment, μ3, of the degenerate v3 in-plane asymmetric C–H stretching vibration of the methyl radical has been made. The measurements were carried out in a flow reactor using laser-photolysis transient infrared absorption spectroscopy. Cyano (CN) radicals (and Cl atoms) were produced by laser photolysis of BrCN (or ClCN) at 193 nm and reacted with methane to give both CH3 and HCN (and HCl). The intensities of 18 rotational lines of the v3 fundamental band were measured relative to the R(8) line of the C–H stretching vibration (v3) of HCN(001←0). The best estimate of the transition dipole moment of the CH3 (00110←0) transition was provided by the measured line intensity for the CH3 (00110←0)rR(3,3) transition and was determined to be μ3=0.0327±0.0021 D. © 1995 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 77 (1970), S. 0 
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: An investigation correlating protein analyses of cervical mucus with sperm penetration tests and an assessment of consistency is presented. When the protein content was below 1·5 μg. per mg. of wet mucus and only albumin was present, sperm penetrability was optimal. When the protein content was greater than 12·5 μg. per mg. of wet mucus and transferrin and immunoglobulin were present in addition to albumin, sperm penetration was severely restricted. Protein analyses are proposed as a useful method of assessing cervical mucus function with particular reference to the effect of progestogens on the genital tract.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 79 (1972), S. 0 
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Patients considered to be at extra risk of fetal loss because of previous history were assessed throughout pregnancy for hormone deficiency by cervical mucus smears, vaginal cytology and total oestrogen excretion. There was a significantly higher incidence of light-for-dates babies when cervical mucus ferning was noted early in pregnancy and persisted or recurred after 16 weeks. Early detection of‘placental insufficiency’by ferning in the mucus would allow closer study of the factors which impair intrauterine growth.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    BJOG 104 (1997), S. 0 
    ISSN: 1471-0528
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Type of Medium: Electronic Resource
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