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  • 1995-1999  (7)
  • 1990-1994  (8)
  • 1
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 77 (1995), S. 3439-3444 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: The dynamic process of subsurface altered layer formation in a Cu-Pt alloy under Ar+ ion bombardment has been studied by sequential Auger electron spectroscopy (AES) and ion scattering spectroscopy (ISS) measurements. For this study, we recently developed a compact coevaporator, which enables Cu and Pt to be deposited at a constant composition ratio (within ±3 at. %) onto a Si substrate cooled to liquid-nitrogen temperature. The average surface composition of the alloy film was monitored by AES throughout the deposition procedure, and the composition of the topmost atomic layer was measured by ISS right after the end of the film deposition. The data show that the topmost atomic layer was considerably Cu-rich while subsurface atomic layers were of constant composition. During Ar+ ion bombardment, however, the surface composition of Cu, measured by sequential AES and ISS, gradually decreased with time toward a steady-state value. The temporal evolution of the composition profile is described. The surface-segregation constant and radiation-enhanced diffusion coefficient for the Cu-Pt alloy under Ar+ ion bombardment are inferred from the measured composition profile. © 1995 American Institute of Physics.
    Materialart: Digitale Medien
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  • 2
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 1187-1195 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Monte Carlo simulations of cascade processes of secondary electron generation in Si, Cu, and Au have been performed to study the energy distribution of backscattered electrons in the low-energy region. Calculation results show that the characteristic hump appearing in the energy distribution above Si-LVV Auger peak in the EN(E) spectrum can be well described by those electrons ejected from the L shell followed by the cascade process. The shape of EN(E) spectra in the low-energy region is dominated by the directly produced secondary electrons and, hence, strongly correlated with the excitation spectrum Im[−1/ε(ω)] for electron generation.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 76 (1994), S. 7180-7187 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: A Monte Carlo simulation code has been developed to describe the x-ray generation in a specimen for electron probe microanalysis (EPMA), enabling x-ray spectra observed by EPMA to be reproduced theoretically. The Monte Carlo simulation is based on the use of the Mott cross section and Bethe stopping power equation in describing elastic and inelastic scattering processes, respectively. With respect to x-ray generation the Sommerfeld theory for bremsstrahlung radiation was described by equations of Kirkpatrick–Wiedmann and of Statham for bremsstrahlung cross section. The up-to-date compilation of mass absorption coefficient by Henke, Gullikson, and Davis [At. Data Nucl. Data Tables 54, 181 (1993)] is used to evaluate attenuation of x-ray intensity. To verify the present Monte Carlo simulation measurements of x-ray spectra for Cu and Rh targets have been performed for primary electron energies of 10–30 keV by energy-dispersive x-ray spectrometry of an electron probe microanalyzer. Excellent agreement between experimental spectra and calculated results has been confirmed in the cases investigated, leading to the conclusion that the Monte Carlo simulation technique will be a powerful tool for more comprehensive understanding of x-ray generation in EPMA specimens. © 1994 American Institute of Physics.
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 64 (1993), S. 3647-3648 
    ISSN: 1089-7623
    Quelle: AIP Digital Archive
    Thema: Physik , Elektrotechnik, Elektronik, Nachrichtentechnik
    Notizen: An evaporation source of simple and compact construction was devised. This source is 20 mm in diameter and 30 mm long; is composed of a ring filament, control aperture, and disk-shaped sample (source) and shield cover; and enables the evaporation of source material to be easily controlled at a constant rate without the use of a feedback system. This evaporation source ensures depositions at constant rates for several hours. Refractory metal films of several thousand angstroms thickness can be deposited onto substrates held 10 cm from the source. Typical performance characteristics in the application to Ti films are presented.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 85 (1999), S. 4231-4237 
    ISSN: 1089-7550
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Effective energy-loss functions were derived for oxygen-adsorbed amorphous silicon surfaces from a reflection electron energy-loss spectroscopy analysis based on the extended Landau theory. This study has revealed that the intensity of the surface-plasmon-loss peak for a clean surface decreases and its peak position shifts towards the lower-energy losses as oxygen exposure proceeds (≤1000 L). To understand the above behavior of the surface-plasmon-loss peak, the distribution of the energy losses was calculated using the hydrodynamic model. The decrease and shift of the surface-plasmon-loss peak has been described with considerable success by assuming that the quasifree static electron density in the vicinity of the silicon surface decreases as oxygen adsorption proceeds owing to oxygen's high electron affinity. © 1999 American Institute of Physics.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 67 (1995), S. 632-634 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Isolated diamond particles grown by chemical vapor deposition on a mirror-polished Si substrate have been studied by cross-sectional transmission electron microscopy. Focused ion beam micromachining enabled the cross-sectional specimen to be carved out precisely at the center of the particle. Atomic scale observation of the diamond/Si interface revealed the presence of an ∼3 nm thick amorphous intermediate layer including a few pits around the nucleation site of the particle. Growth mechanism and relationship between growth orientation and internal defect structure of the diamond particle are discussed. © 1995 American Institute of Physics.
    Materialart: Digitale Medien
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  • 7
    Digitale Medien
    Digitale Medien
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 68 (1996), S. 2070-2072 
    ISSN: 1077-3118
    Quelle: AIP Digital Archive
    Thema: Physik
    Notizen: Defect structures in a homoepitaxial diamond film grown by chemical vapor deposition have been studied by cross-sectional transmission electron microscopy. Many interstitial dislocation loops are discerned in the (001) interface. The internal region grown on the (11¯1) facet comprises stacking faults and twins, while that on the (001) face contains mainly interstitial dislocation loops aligned in rows along ∼〈112〉 directions. Fe and Si impurities were detected only at the interface by analytical electron microscopy. The origin of the defects is briefly discussed. © 1996 American Institute of Physics.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    Springer
    European journal of clinical pharmacology 41 (1991), S. 335-337 
    ISSN: 1432-1041
    Schlagwort(e): Gastric emptying ; AS-4370 ; healthy adults ; benzamide analogue ; acetylcholine release
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Chemie und Pharmazie , Medizin
    Notizen: Summary The effect of AS-4370 on gastric emptying was investigated in healthy adults using 99mTc-DTPA. Single doses of AS-4370 2.5, 5 or 10 mg or placebo were administered to 12 subjects in a controlled, double-blind, cross-over study. Tests were performed twice weekly in each subject. Thirty min after administration of test drug or placebo, each subject swallowed a bun and orange juice containing 200 μCi nuclide. The radioactivity of the gastric content was measured for 40 min and the activity of the residue was expressed as a percentage of count at the initiation of measurements. The percentage radioactivity, AUC and gastric emptying time fitted by a power exponential curve, were analyzed. No significant difference was observed between the three dose levels of AS-4370 and placebo in half emptying time. However, decreases in the percentage of radioactivity with time were noted: 5 mg at 10 to 16 min and 10 mg at 8 to 24 min after the start of recording. Lower AUCs after 5 mg and 10 mg compared to placebo were also found. The half emptying time was also shorter after 5 mg and 10 mg than placebo. There was no difference in these parameters between 2.5 mg and placebo. The results indicate that AS-4370 5 and 10 mg but not 2.5 mg accelerates gastric emptying in healthy adults.
    Materialart: Digitale Medien
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  • 9
    Digitale Medien
    Digitale Medien
    Springer
    Journal of mathematical sciences 93 (1999), S. 600-608 
    ISSN: 1573-8795
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Mathematik
    Notizen: Abstract Let F(x) be a distribution function of of a scale mixture X=SZ of a random variable Z with distribution G and scale factor S, which is a positive random variable independent of Z. Some nonuniform bounds are given for asymptotic expansions of F(x) around G(x)_ under mild moment conditions on the distribution of S. Some nonuniform bounds for the normal approximation to the Student t-distribution are given as examples.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Chichester [u.a.] : Wiley-Blackwell
    Surface and Interface Analysis 16 (1990), S. 140-143 
    ISSN: 0142-2421
    Schlagwort(e): Chemistry ; Polymer and Materials Science
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Physik
    Notizen: The Japanese VAMAS-SCA working group is composed of 19 institutes. Three kind of Au—Cu alloys (Au 75 at.-%-Cu 25 at.-%, Au 50 at.-%-Cu 50 at.-%, Au 25 at.-%-Cu 75 at.-%) were prepared, and these specimens, pure Au and pure Cu were distributed to the members of the VAMAS-SCA working group. The surface concentrations of these alloys were calculated from the Auger peak amplitudes in two ways. One method used the published relative sensitivity factors, and the other used pure Au and Pure Cu as the standard materials. The mean values of the surface concentrations calculated with the published relative sensitivity factors were almost the same as those calculated with the standard materials. This means that the published relative sensitivity factors are reliable to some extent. The error of the surface concentration calculated with pure Au and pure Cu as the standard materials lay between about 3% and 10%, and that with the relative sensitivity factors lay between about 7% and 20%. The calculated surface concentrations of Au were larger than the bulk concentrations of Au when the matrix effect was neglected.
    Zusätzliches Material: 7 Ill.
    Materialart: Digitale Medien
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