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  • 1
    Electronic Resource
    Electronic Resource
    Resolution enhancement in three-dimensional confocal microscopy (1991)
    Springer
    Machine vision and applications 4 (1991), S. 233-242 
    Details
    ISSN: 1432-1769
    Keywords: Optical sectioning property ; lateral resolution ; confocal scanning optical microscope ; pupil plane filter ; composite image
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Notes: Abstract We discuss various methods of tuning and improving both the optical sectioning strength and the lateral resolution of the confocal scanning optical microscope. Techniques based on using different wavelengths, pupil plane filters, different sized detectors and laterally displaced detectors are considered and experimental results presented. Both bright field reflection and fluorescence imaging are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01815300
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  • 2
    Electronic Resource
    Electronic Resource
    Abundances in the interstellar medium (1992)
    Springer
    The astronomy and astrophysics review 4 (1992), S. 1-33 
    Details
    ISSN: 1432-0754
    Keywords: Isotopes-Galaxy ; Evolution of-Interstellar Medium ; abundances
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Summary Recent developments in the theory of element production and the chemical evolution of the galaxy are presented. Following this, observational data and their interpretation are given. A case by case analysis of results for D, He, Li and CNO isotope data in the disk and center of our galaxy is presented; previous results for element gradients are also summarized. The primordial abundances of D and He cannot be directly obtained from observations; corrections for stellar processing are discussed. From these data and the Li abundances, it appears that the abundance of the light elements is consistent with the standard big bang. In agreement with previous results, the range ofη, the baryon to photon ratio, is 5–8 10−10. If the amount of non-baryonic matter is small, these results indicate an open universe, in the standard big bang model. New data show a gradient in the (12C/13C) and (16O/18O) ratios with galactocentric distance, DGC. The presence of a gradient in the (14N/15N) ratio is less clear and there is no measurable gradient in the (32S/34S) ratio. In the interstellar medium near the sun, the carbon isotope ratio is −20 percent lower than the solar system ratio. This indicates that there has been only a moderate amount of enrichment of the nearby interstellar medium since the formation of the solar system. These results and previously determined galactic element gradients are interpreted in the framework of chemical evolution models. Delayed recycling of nucleosynthesis products is essential for the correct interpretation of the results. Comparisons of data with galactic evolution models are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00873568
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  • 3
    Electronic Resource
    Electronic Resource
    Rovibrational excitation of carbon monoxide by energy transfer from metastable nitrogen (1990)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 92 (1990), S. 1758-1767 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The CO fundamental vibration–rotation spectra resulting from the interaction of discharged nitrogen with carbon monoxide at low pressure (∼3 mTorr) exhibit bimodal rotational distributions. We have identified 14 vibrational levels of a rotationally relaxed (80 K) component and eight vibrational levels from a rotationally excited component. The eight rotationally excited bands are best reproduced by a statistical distribution E=ER+EV=3.7 eV, which provides sufficient population in the region of the Fortrat reversal (J∼90) to account for the observed R-branch bandhead formation. The rotationally relaxed vibrational levels are populated by single- and two-quantum transfer from N2(v), N2(v)+CO→N2(v−1,2)+CO(v=1,2), and radiative cascade from CO(A) produced by quenching of N2(a'), N2(a' 1Σ−u) +CO→N2(X,v)+CO(A 1Π)→CO(v≤9)+hν, and relaxation of the rotationally excited component. Kinetic and energetic arguments indicate that a branch of N2(a') quenching N2(a' 1Σ−u) +CO→N2(X,v)+CO(v≤14,J) is responsible for the rotationally excited component. Surprisal analysis indicates two dynamic mechanisms are responsible for the rotationally excited component. We have modeled the vibrational distribution of the rotationally excited component with equal contributions from a statistical (all v) process and a process favoring excitation of low vibrational levels (v≤4).
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.458057
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  • 4
    Electronic Resource
    Electronic Resource
    The Primordial Abundance of 3-Helium and Deuterium (1993)
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 688 (1993), S. 0 
    Details
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1749-6632.1993.tb43967.x
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  • 5
    Electronic Resource
    Electronic Resource
    Quenching of triplet acetone by mesitylene and durene: exciplex formation or energy transfer? (1992)
    s.l. : American Chemical Society
    The @journal of physical chemistry 〈Washington, DC〉 96 (1992), S. 8967-8973 
    Details
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/j100201a050
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  • 6
    Electronic Resource
    Electronic Resource
    Generation of high repetition rate far-infrared laser pulses (1994)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 64 (1994), S. 3383-3385 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We report the generation of pulsed optically pumped far-infrared (FIR) radiation with a repetition rate of 200 kHz. These pulses were obtained in a straightforward method by pumping a FIR resonator with a high repetition rate, rf-excited, waveguide CO2 laser. Pulses approximately 50 ns wide were generated both at 432.6 μm in HCOOH, and 117.7 μm in CH2F2. The pulse width of the FIR radiation was studied as a function of the CO2 pulse width, and the relative delay between the two was measured. Based on this data we conclude that the FIR radiation was gain switched and of a duration which was a function of either the gain bandwidth of the FIR transition, or more likely the FIR cavity parameters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.111282
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  • 7
    Electronic Resource
    Electronic Resource
    Optical diagnostic methods for the study of fuel fouling (1992)
    s.l. : American Chemical Society
    Industrial & engineering chemistry research 31 (1992), S. 2243-2251 
    Details
    ISSN: 1520-5045
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/ie00009a023
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  • 8
    Electronic Resource
    Electronic Resource
    Comment on "Image formation in a superresolution phase conjugate scanning microscope'' (1991)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 58 (1991), S. 314-314 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.104673
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  • 9
    Electronic Resource
    Electronic Resource
    Effects of ranitidine, given t.d.s., on intragastric and oesophageal pH in patients with gastrooesophageal reflux (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Alimentary pharmacology & therapeutics 5 (1991), S. 0 
    Details
    ISSN: 1365-2036
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The purpose of this study was to determine the effects of 150 mg ranitidine, 300 mg ranitidine or placebo, administered every 8 h, on gastro-oesophageal pH and heartburn parameters in reflux patients. Twelve symptomatic reflux patients received each of the three treatments in a randomized, double-blind, crossover fashion. Intragastric and oesophageal pH were monitored continuously for a 24 h period. Meals were standardized, consumed at set times and patients were allowed to recline and sleep from 23.00 hours until 06.00 hours only. The gastric record was analysed for the percentage of time that the pH was ≧ 4. The oesophageal record was analysed for acid contact time (percentage time (%) pH ≦ 4.0) and reflux episode frequency. Finally, patients recorded each new episode of heartburn and graded daytime heartburn severity at the end of each hour. Ranitidine increased the median (%) time that the intragastric pH remained at or above 4, from 4.5 (placebo) to 33.9% (150 mg dose) and 33.3% (300 mg dose). Ranitidine dose-dependently reduced the median 24-hour oesophageal acid contact time from 13.3% (placebo) to 6.8% (150 mg dose) and 2.5% (300 mg dose). The 300 mg dose significantly reduced daytime heartburn episode frequency and severity while the 150 mg dose reduced heartburn severity only. We conclude that 150 and 300 mg doses of ranitidine administered every 8 h have major, sometimes dose-dependent effects on the objective parameters and symptoms of gastro-oesophageal reflux.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-2036.1991.tb00530.x
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  • 10
    Electronic Resource
    Electronic Resource
    Leaf teeth, transpiration and the retrieval of apoplastic solutes in balsam poplar (1991)
    Oxford, UK : Blackwell Publishing Ltd
    Physiologia plantarum 83 (1991), S. 0 
    Details
    ISSN: 1399-3054
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The rapid flow of the transpiration stream through major veins to leaf teeth was followed in leaves of Populus balsamifera L., using the tracer sulphorhodamine G (SR), which probes for cells with H+-extrusion pumps. The tracer accumulated quickly in the hydathodes of the teeth. It was shown by freeze-substitution and anhydrous processing that SR was taken up by phloem parenchyma and epithem cells of the hydathode. When 14C-labelled aspartate was fed to the leaves in the transpiration stream, it also was taken up most strongly by the same phloem parenchyma and epithem cells. It is proposed that one function of the hydathodes in leaf teeth is the retrieval of solutes from the transpiration stream.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1399-3054.1991.tb02146.x
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