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  • 1
    Digitale Medien
    Digitale Medien
    Springer
    Applied physics 38 (1985), S. 11-15 
    ISSN: 1432-0649
    Schlagwort(e): 42.68 ; 42.80 ; 07.65
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract This paper reports for the first time the fully optical remote monitoring of low-level CH4 gas with a wide area coverage of 10 km in diameter realized by utilizing ultralowloss silica optical fibre link and a compact absorption cell in conjunction with highly radiant InGaAsP and InGaAs light emitting diodes (LEDs) in the near infrared region. For this novel application, the near-infrared absorption spectra of CH4 molecules were measured and studied involving the ν2+2ν3 combination band around 1.33 μm and the 2ν3 overtone band around 1.66 μm. This fibre-optic system was demonstrated to be feasible and sufficiently sensitive and safe as being a practical CH4 gas remote sensor whose detection sensitivity is normally required to be 25% of the lower explosion limit (LEL) of CH4 gas in air. This result verifies a large potential for applying extensively to various strategic points within the environment, such as industrial and mining complexes as well as urban and residential areas, with considerably increased reability, safety and marketability over the presently available techniques.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 16 (1995), S. 307-316 
    ISSN: 0197-8462
    Schlagwort(e): thermography ; temperature ; phantom ; dielectric properties ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Physik
    Notizen: The possibility of tissue heating due to an auditory brainstem implant (ABI) or a modified cochlear implant (CI) during magnetic resonance imaging (MRI) of the head was tested on a full-sized human phantom using a realistic phantom head consisting of simulated skull, brain, and muscle. Dielectric properties of the brain, muscle, and bone materials were similar to those of human tissues at 64 MHz. The body consisted of homogeneous phantom muscle enclosed in a human-shaped fiberglass shell. Thermographic and fiber-optic temperature measurements were conducted to reveal any heating. Thermograms of sagittal, frontal, and horizontal planes of the head with the ABI and CI electrodes were taken immediately before and after a 26 min MRI scan. The MRI sequence was set at 94 excitations and 25 ms echo time to induce maximum radiofrequency heating, as suggested by the General Electric Company. The difference of these two thermograms gives the heating results. In two uncut phantom heads, Teflon tubes were placed along the implanted ABI and CI, and temperature data were recorded via fiber-optic probes before, during, and after the MRI. Results showed no observable heating associated with the ABI and the modified CI during worst-case MRI of the head. © 1995 Wiley-Liss, Inc.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Hoboken, NJ [u.a.] : Wiley-Blackwell
    Journal of Orthopaedic Research 5 (1987), S. 217-230 
    ISSN: 0736-0266
    Schlagwort(e): Knee joint, biomechanics ; Ligaments, articular ; Buckle transducer ; Life and Medical Sciences
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Tensions generated in selected bands of the four major ligaments of the flexed knee (40-90°) have been measured in vitro when the tibia is subjected to passive anterior translation and axial rotation with and without a compressive preload. The measurements were made in 30 fresh-frozen specimens using the buckle transducer attached to the anteromedial band of the anterior cruciate ligament [ACL (am)], the posterior fibers of the posterior cruciate ligament [PCL (pf)], the superficia fibres of the medial collateral ligament [MCL (sf)], and in the total lateral collateral ligament (LCL). Particular attention was placed on the evaluation of the performance of the transducer specific to such measurements in order to minimize the errors associated with the use of this transducer. The results indicate that, among the measured ligaments, substantial tension (〉20 N) is generated only in the ACL (am) in tibial anterior translation up to 5 mm. The tension pattern generated in response to tibial axial rotation, however, is complex and exhibits considerable variation between specimens. In general, both the MCL (sf) and LCL are tensed at all tested flexion angles, with the tension in external rotation being significantly greater than in internal rotation. At 40° of flexion, the ACL (am) bears tension mainly in internal rotation, while at 90° of flexion the PCL (pf) is tensed in both senses of rotation. The response of the LCL shows marked variation among specimens; very small tension (15 N) is generated in internal rotation in 48% of the specimens, and in either sense of rotation in 20% of the specimens. The tension in the ACL (am) in internal rotation is invariably greater in those specimens in which LCL tension is negligible. This correlation between increased ACL (am) function and inadequate LCL restraint appears significant in terms of ACL injury and repair.
    Zusätzliches Material: 12 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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