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  • 1990-1994  (4)
  • 1975-1979
  • 1920-1924
  • 78.55.Cr  (1)
  • Cerebral fat embolism  (1)
  • Disk cathode  (1)
  • Ethylcarbazolylalaline  (1)
Materialart
Erscheinungszeitraum
  • 1990-1994  (4)
  • 1975-1979
  • 1920-1924
Jahr
Schlagwörter
  • 1
    ISSN: 1438-2199
    Schlagwort(e): Amino acids ; Unnatural amino acid ; Ethylcarbazolylalaline ; Vesicular assembly ; Photoenergy-harvesting system
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary A novel unnatural amino acid, L-3-(3-N-ethylcarbazolyl)alanine, was synthesized and used for synthesis of a chiral dialkylammonium-type amphiphile. The synthetic amphiphile formed a vesicular assembly in aqueous dispersion showing gel-liquid crystalline phase transition around 25 °C. The bilayer membrane composed of the amphiphile was nearly free from excimer as evidenced by fluorescence spectroscopy.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1432-0630
    Schlagwort(e): 78.55.Cr ; 78.30.Gt ; 81.20.-n
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Maschinenbau , Physik
    Notizen: Abstract Mg+ ions were implanted into highly pure InP grown by the liquid encapsulated Czochralski (LEC) method in which the Mg concentration [Mg] was varied between 1×1015 cm−3 and 3×1020 cm–3. Two annealing methods were used: furnace annealing (FA) up to 740° C and flash lamp annealing (rapid thermal annealing, RTA) up to 900° C. For characterization, photoluminescence (PL) spectra were measured between 2K and room temperature together with Raman scattering measurements at room temperature. An emission designated by g, which was attributed to a novel energy state of an isolated acceptor, was found to be produced for a rather low value of [Mg]. In addition, a broad emission denoted by [g−g], which was ascribed to acceptor-acceptor pairs, was observed below bound exciton emissions for moderate values of [Mg]. These features were quite similar to those previously observed in acceptor-doped GaAs when the background concentration of donors is extremely low. Two additional novel emissions located far below the band-to-acceptor emission were also obtained, and each showed a remarkable energy shift towards lower energy with increasing [Mg]. The binding energies of these emissions were estimated from the temperature dependence of PL spectra and the results suggest that they are complex-type radiative recombination centers, presumably donor-acceptor-type centers. A strong broad emission centered near the band-to-acceptor emission was observed for [Mg]=3×1020 cm−3. This observation indicates a formation of a new material between In, P and Mg, which was also attested by the appearance of a new TO-like Raman signal for [Mg] greater than 1×1019 cm−3. A substantial difference of PL and Raman spectra was revealed for the two annealing methods, suggesting that the annealing behaviour of ion-implanted InP should be investigated more extensively in order to establish reliable annealing procedures.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    Springer
    Neuroradiology 33 (1991), S. 72-74 
    ISSN: 1432-1920
    Schlagwort(e): Magnetic resonance imaging ; Cerebral fat embolism
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Summary The cerebral fat embolism is a potentially serious complication of fractures but clinical cases often go undiagnosed. Two cases of clinically diagnosed cerebral fat embolism are reported, and MR images of these patients are described. While brain CT revealed no abnormality, MR imaging showed relative low-intensity areas on T1-weighted images and high-intensity areas on T2-weighted images. In one patient follow-up MR showed nearly complete resolution of the abnormal signal. MR imaging appears to be valuable for detecting the lesions in these patients.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Medical & biological engineering & computing 31 (1993), S. S37 
    ISSN: 1741-0444
    Schlagwort(e): Cold-cathode diode ; Disk cathode ; Flash X-rays ; Photon energy control ; Pulsed X-rays ; Tube current control
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie , Medizin
    Notizen: Abstract Fundamental studies of a repetitive flash X-ray generator using a diskcathode radiation tube are described. The high-voltage pulser employed a modified two-stage surge-Marx circuit. The two condensers in the pulser were charged from 40 to 60 kV, and the electric charges were discharged to the X-ray tube repetitively to generate flash X-rays. The total capacity during the main discharge was 425 pF, and the maximum output voltage from the pulser was about 1·9 times the charged voltage. The flash X-ray tube of the demountable-diode type and was composed of a rodshaped anode tip made of tungsten, a disk cathode made of graphite and a tube body made of polymethylmethacrylate. The peak tube voltage was primarily determined by the anode-cathode (A-C) space, and the peak tube current was less than 0·5 kA. Thus the maximum photon energy could be easily controlled by varying the A-C space, and the tube current roughly increased according to increases in the charged voltage. The pulse width ranged from 40 to 100 ns, and the X-ray intensity was less than 1·1 μC kg−1 at 0·5 m per pulse. The repetition rate was less than 50 Hz, and the effective focal spot size was equivalent to the anode diameter.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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