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  • Artikel: DFG Deutsche Nationallizenzen  (19)
  • Digitale Medien  (19)
  • 1995-1999  (8)
  • 1990-1994  (10)
  • 1985-1989  (1)
  • 1
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The effect of thermal-diffusion charge on the x-ray energy response of silicon surface-barrier (SSB) detectors have generally been ignored; consequently, the SSB response has been believed to be analyzed using the thickness of the depletion layer alone. Our new theory on the SSB x-ray response [J. Appl. Phys. 72, 3363 (1992)] was prepared for addressing recent confusion on plasma x-ray analyses using SSB detectors [Rev. Sci. Instrum. 59, 1380 (1988); 61, 693 (1990); 63, 4850 (1992)]. This approach was made under the assumption of a dominant contribution of the diffusion-charge signal in the vicinity of the x-ray incident location because of the strong reduction of the x-ray produced charge within the thermal-diffusion length. In this report, the comparison between this approximation (having an approximated solution) and the exact numerical calculation (using an integral form) is carried out. Necessity and importance of such three-dimensional treatments for the data analyses as well as the design of multichannel semiconductor-array detectors developed for plasma x-ray tomography diagnostics are highlighted. Furthermore, for the total diffusing-charge amount, the calculated results from our theory and the values using the comment from Donolato agree well within the accuracy of 1%.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: An analytical method based on a new theoretical model for the x-ray energy responses of silicon surface-barrier (SSB) detectors has been proposed. This method may address a recent confusing issue in the x-ray detection characteristics of SSB semiconductor detectors; that is, the x-ray responses of SSB detectors as well as p-i-n diodes used in underbiased operations were recently found to be contrary to the commonly held belief that the x-ray sensitivity of an SSB detector is determined by the thickness of the depletion layer. The model presented includes a signal contribution from thermally diffusing charge that is created in the field-free substrate region within a diffusion length from the depletion layer along with a signal contribution from charge created in the depletion layer. This model predicts a large signal contribution from the charge-diffusion effect on the SSB responses to high-energy x rays. Formulas and calculated results supporting SSB calibration data have been represented. These analytical methods might be developed to apply the analyses and predictions of energy responses of various types of silicon detectors including p-i-n diodes as well as charge-coupled devices.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    New York, NY : American Institute of Physics (AIP)
    Physics of Fluids 4 (1992), S. 1023-1032 
    ISSN: 1089-7666
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Absolute instability in a plasma-filled backward wave oscillator with sinusoidally corrugated slow wave structure driven by an intense relativistic electron beam has been analyzed numerically. The maximum spatial growth rate of the plasma-filled waveguide is found to be larger than that of an optimally designed vacuum structure. The excitation of a finite length structure is investigated. Although the spatial growth rates obtained in the linear theory increase with plasma density in the finite length plasma-filled structure for the fundamental TM01 mode of oscillation, negative global spatial growth rates prevent the coherent oscillation for intermediate ranges of plasma density, beam current, and even for structure length.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Springer
    Journal of applied electrochemistry 20 (1990), S. 240-244 
    ISSN: 1572-8838
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Abstract A new exclusion process for CO and CO2 from ammonia synthesis gas has been proposed: this takes place at room temperature and atmospheric pressure. The process is based on the electrochemical reduction of CO and CO2 to methanol proceeding at a mediated electrode via homogeneous catalysis. The maximum percentages of CO and CO2 excluded from the initial gas were about 1.5 and 4.1%, respectively, with a mediated electrode of 82.8 cm2 area in a reaction time of 5 h. The amount of excluded CO and CO2 was equivalent to the sum of moles of methanol formed and gases dissolved into the solution alone. The electroreduction of CO and CO2 was more efficient at three-phase (electrode/solution/gas) and at two-phase (electrode/solution) interfaces, respectively.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    Springer
    Journal of applied electrochemistry 24 (1994), S. 1164-1169 
    ISSN: 1572-8838
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: Abstract Poly(N-methylaniline) (PNMA) was prepared on a bare platinum electrode by electrooxidation of N-methylaniline in 1.0 mol dm−3 HCl. The PNMA film was more stable to anodic treatment than the polyaniline film. The electric conductivity of the PNMA film was potential dependent. High conductivity appeared only within the potential region where PNMA itself was redox-active. The PNMA filmed electrode showed redox response to dissolved hydroquinone whose redox current was evident within the potential region. Furthermore, the PNMA film behaved as an electrocatalyst for the electrode reaction of hydroquinone. The kinetics of the electrocatalytic reaction were investigated mainly using a rotating disc electrode. The experimental results obtained were analysed by the theory of Albery and Hillman, and the rate constant of the electron cross-exchange transfer between hydroquinone and the redox-active sites in the film (k) was determined and found to be 6.4 × 103 m −1 s−1 at 20° C.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 51-52 (Jan. 1991), p. 349-354 
    ISSN: 1013-9826
    Quelle: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Thema: Maschinenbau
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    Digitale Medien
    Digitale Medien
    Springer
    Pediatric surgery international 12 (1997), S. 618-619 
    ISSN: 1437-9813
    Schlagwort(e): Ductoplasty ; Anatomic variation ; Biliary reconstruction ; Choledochal cyst
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The confluence of the right and left hepatic ducts at the hepatic hilum frequently shows normal anatomic variations. Choledochal cysts (CC) are also accompanied by similar variations, and devices for free drainage of bile are occasionally required in biliary reconstruction. We present a CC that had an aberrant posterior branch of the right hepatic duct draining into the distal common hepatic duct. A capacious hepaticoduodenostomy at the hilum was performed after joining the hilar and aberrant ducts.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    ISSN: 1437-9813
    Schlagwort(e): Key words Cryptorchidism  ;  Apoptosis  ;  Germ cells  ; TUNEL method
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract We investigated the possible involvement of apoptosis in the increased germ-cell degeneration in undescended testes (UDT). Experimental unilateral cryptorchidism was induced in 21-day-old rats, and both testes were removed for in-situ TUNEL staining of apoptotic cells at 1, 3, 7, 10, and 14 days postoperation. A gradual increase in the incidence of apoptosis was seen at 21–28 days of age in the control testes, followed by a decrease thereafter. After 10 days postoperation, the weight of the UDT was significantly lower than that of the contralateral descended testis (CDT) and the controls. However, the weight of scrotal testes in each group was similar. UDTs demonstrated a markedly increased incidence of apoptosis. By 7 days postoperation, the percentage of seminiferous tubules containing apoptotic germ cells significantly increased in UDTs compared with that in CDTs and controls (P 〈 0.001). Moreover, there was a significant difference in the percentage of seminiferous tubules containing apoptotic germ cells between CDTs and controls (P 〈 0.01). In addition, an increased incidence of seminiferous tubules containing 8–10 and 〉10 apoptotic germ cells from 7, 10, and 14 days postoperation in UDTs was detected. In-situ TUNEL analysis demonstrated spermatocytes to be the main type of germ cells affected in all groups. These findings suggest that spermatogenesis decreases not only in the␣UDT, but also in the CDT, and that the germ-cell degeneration in cryptorchidism took the form of apoptosis.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Pediatric surgery international 13 (1998), S. 414-415 
    ISSN: 1437-9813
    Schlagwort(e): Key words Gastroesophageal reflux ; Hiatal hernia ; Omphalocele
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract Esophageal hiatal hernias (EHH) are probably caused by congenital, traumatic, or iatrogenic factors, although the etiology remains unknown. EHHs may develop after abdominal wall closure for omphalocele or gastroschisis due to the increased intra-abdominal pressure, however, there have been few reports in the literature. We present a case of EHH developing after abdominal wall closure.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Pediatric surgery international 12 (1997), S. 618-619 
    ISSN: 1437-9813
    Schlagwort(e): Key words Ductoplasty ; Anatomic variation ; Biliary reconstruction ; Choledochal cyst
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Medizin
    Notizen: Abstract The confluence of the right and left hepatic ducts at the hepatic hilum frequently shows normal anatomic variations. Choledochal cysts (CC) are also accompanied by similar variations, and devices for free drainage of bile are occasionally required in biliary reconstruction. We present a CC that had an aberrant posterior branch of the right hepatic duct draining into the distal common hepatic duct. A capacious hepaticoduodenostomy at the hilum was performed after joining the hilar and aberrant ducts.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
    BibTip Andere fanden auch interessant ...
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