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  • 1
    Digitale Medien
    Digitale Medien
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 92 (1990), S. 3693-3699 
    ISSN: 1089-7690
    Quelle: AIP Digital Archive
    Thema: Physik , Chemie und Pharmazie
    Notizen: The authors have used a fast expansion cloud chamber to measure binary homogeneous nucleation rates in several ethanol–water mixtures as a function of temperature, ethanol and water activities and nucleation rate. Data (ethanol and water activities) are presented for a range in nucleation rate from 103 to 105 drops/cm3 s from 263 to 293 K for mixtures having mole ratios (ethanol/water) of 10, 4, 0.1, 0.01, and 0.001. A comparison of the extensive data set to other data in the literature shows good agreement. We find current theory, as expected, is unable to accurately predict the data at low ethanol concentrations.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 2801-2807 
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: We describe a sensitive polarimeter for measuring optical rotation induced by chiral molecules in solution that operates in the reflectance mode. A polarized light beam is made to pass through a liquid sample two or more times before detection by reflecting the beam from the surface of the sample container. The optical activity of the sample is measured using a differential polarization detector. Our results show that, for certain initial polarization states and angular orientations of the beam with respect to the glass interfaces, high sensitivity to changes in the concentration of the sample can be achieved. Results of a theoretical analysis of the technique were confirmed by experiments in which optical rotation of glucose in water was measured using a simple apparatus that employs a light-emitting diode source. Glucose sensing in vivo and on-line monitoring of industrial processes using integrated optoelectronic sensors are discussed as potential applications.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 638-644 
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: In most optical methods proposed for imaging an absorbing object embedded in a turbid medium, data are collected using a single source and detector scanned mechanically across the surface of the medium. In our setup, we exploited destructive interference of diffusive photon density waves originating from two sources to localize an absorbing (or fluorescent) body in a scattering medium. A frequency-domain instrumentation is described that scans several laser-beam spots across the surface of a turbid medium using 1D (or 2D) acousto-optical deflectors. An additional acousto-optic deflector is used to establish arbitrary phase shifts for the interfering photon-density waves. A destructive interference pattern was created to laterally localize an absorbing (or fluorescent) body in the reflection and transmission modes. In some experiments the destructive interference pattern was altered by modulating the individual beam intensities to improve sensitivity and ameliorate surface texture problems. The experimental results were retrieved from a gated intensified CCD camera at 246 MHz modulation frequency. Results indicate that less than a 1 mm displacement of a small object embedded 10 mm in a medium with optical characteristics similar to bloodless skin tissue can be detected.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    Journal of the American Chemical Society 78 (1956), S. 5978-5983 
    ISSN: 1520-5126
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    Journal of the American Chemical Society 80 (1958), S. 1389-1391 
    ISSN: 1520-5126
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    Journal of the American Chemical Society 78 (1956), S. 2169-2171 
    ISSN: 1520-5126
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 79 (1996), S. 8507-8511 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The properties of interface traps in metal–silicon nitride (deposited by jet vapor deposition technique) –silicon (MNS) capacitors have been studied in some detail. In comparison with those in metal–oxide–Si capacitors, the interface traps in our MNS capacitors exhibit the following major differences: (i) ∼2 orders of magnitude higher time constants; (ii) no evidence of two distinguishable defects following irradiation as revealed by the ac conductance measurement; and (iii) absence of latent generation of interface traps following irradiation. On the other hand, the interface-trap transformation process following irradiation is qualitatively similar in silicon nitride and thermal oxide devices. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 75 (1994), S. 1074-1087 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Hydrogenated amorphous-silicon (a-Si:H) -based solar cells consist of two electrodes and a p-i-n structure, deposited on glass substrates. Depositing the p-i-n layers and the back metallic electrode on an optically rough transparent conducting oxide (TCO) electrode enhances the absorption of the incident light in the active i layer: Light is scattered at the rough front interface and is partially trapped in the high refraction index layer, as in a waveguide. In addition TCO roughness increases the front transmission coefficient, increasing the amount of light in the active layer. TCO texture yields a relative increase of the conversion efficiency up to 30%. A semiempirical model of thin-film solar-cell optics is presented, taking into account the interface roughness by introducing experimentally derived scattering coefficients and treating the propagation of specular light in a rigorous way. Numerically simulated spectral response and total reflectance of standard solar cells deposited on different TCO textures are compared to experimental data. The results show a better fit to measured characteristics than simulations obtained by previous semiempirical modeling. Improvements mainly come from the light propagation calculation. According to the model, the number of passes incident light may make through the active i layer reaches six for the most efficient cell. As an example of the model's main application, the enhancement of the conversion efficiency that would be expected from an optimized TCO layer is calculated for each texture studied and for different back metallizations.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    The @journal of organic chemistry 46 (1981), S. 754-757 
    ISSN: 1520-6904
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Oxford, UK and Boston, USA : Blackwell Publishing Ltd.
    The @journal of child psychology and psychiatry 41 (2000), S. 0 
    ISSN: 1469-7610
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin , Psychologie
    Notizen: Functional imaging studies of developmental dyslexia have reported reduced task-related neural activity in the temporal and inferior parietal cortices. To examine the possible contribution of subtle anatomic deviations to these reductions, volumes were measured for the major lobes of the brain, the subcortical nuclei, cerebellum, and lateral ventricles on magnetic resonance imaging (MRI) scans from 16 right-handed dyslexic men, ages 18 to 40, and 14 matched controls, most of whom had previously undergone PET imaging. A specific decrease in tissue volume was localized to the temporal lobes and was particularly prominent on the left (p 〈 01). An analysis of tissue composition revealed that this reduction was primarily attributable to decreased gray matter within the left temporal lobe (p 〈 002). Further segmentation of the temporal lobe showed that this reduction was not confined to the superior temporal gyrus, the primary location of primary auditory cortex. Reductions of temporal lobe gray matter may reflect a regional decrease in neuronal number or neuropil, which in turn may result in reading impairment.
    Materialart: Digitale Medien
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