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  • 1
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 91 (2002), S. 676-685 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Heteroepitaxial diamond films can be grown by bias enhanced nucleation on iridium buffer layers followed by an appropriate textured-growth step. Unlike epitaxial diamond films on silicon, the mosaicity reduction during textured growth includes tilt as well as twist. We conclude that different mechanisms causing the grain coarsening are working in the two cases. It is shown that the principle of evolutionary selection can be excluded as a decisive mechanism in the present films. Merging of neighboring grains by disclination formation yields an alternative explanation, that can convincingly substantiate the differences between the textured growth on iridium and silicon. From a Monte–Carlo type simulation describing the texture evolution due to merging of grains, a simple functional correlation between grain coarsening and mosaicity reduction is deduced. Comparison between simulation and experiment allows one to estimate the contributions of different processes. Finally, the general significance of the present findings for other materials is discussed. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 88 (2000), S. 2456-2466 
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The residual stress in thin diamond films with a strongly improved heteroepitaxial alignment has been studied by x-ray diffraction and micro-Raman spectroscopy. The measurements have been compared with the predictions from finite element simulations. The diamond films have been deposited by microwave plasma chemical vapor deposition at a temperature of 700°C on thin (200 nm) iridium buffer layers on SrTiO3(001). Three different regions have been found for a 600 nm thick diamond film: (I) a high quality epitaxial central area with 〉109 cm−2 oriented diamond grains showing a mosaic spread of only (approximate)1°; (II) a ringlike area of isolated epitaxial islands; and (III) a nontextured closed film at the edge of the sample. In area I the stress tensor was determined from the mean shift of the x-ray Bragg reflections. It can be interpreted in terms of a plane, biaxial stress state with σ=−4.9 GPa which is confirmed by micro-Raman measurements. Analyzing the diamond (004) and (311) peak profiles measured by x-ray diffraction (XRD) using monochromatic CuKα1 radiation allows us to distinguish a strongly shifted main component and a weaker, broader component with a minor shift. Finite element simulations predict a pronounced elastic relaxation of the thermal stress at rugged surfaces thus explaining this minor component. They also substantiate a stress reduction by more than 80% as observed by Raman measurements in area II. Combining all measurements taken in the different areas with the predictions of the simulation allows to separate four contributions, i.e., the thermal stress, elastic stress relaxation at a rugged surface, inhomogeneous stress contributions from the coalescence of the grains, and finally coherence stress due to lattice misfit. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 74 (1999), S. 650-652 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Heteroepitaxial diamond films with highly improved alignment have been realized by using the layer sequence diamond/Ir/SrTiO3(001). In a first step, epitaxial iridium films with a misorientation 〈0.2° have been deposited on polished SrTiO3(001) surfaces by electron-beam evaporation. Using the bias-enhanced nucleation procedure in microwave plasma chemical vapor deposition, epitaxial diamond grains with a density of 109 cm−2 could be nucleated on these substrates. The orientation relationship for this layer system is diamond(001)[100](parallel)Ir(001)[100](parallel)SrTiO3(001)[100]. The polar and azimuthal spread for the crystal orientation of a 600 nm thick diamond film is about 1° in each case. For an 8 μm thick diamond film a significantly improved alignment of 0.34° (polar) and 0.65° (azimuthal) has been measured. The latter values, which to the best of our knowledge are superior to those of all former reports about epitaxial diamond films on alternative substrates, indicate the high potential of the substrate Ir/SrTiO3 for the realization of large-area single-crystalline diamond films. © 1999 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 78 (2001), S. 192-194 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: It is shown that diamond nucleation on iridium buffer layers followed by an appropriate textured-growth step offers a viable way to realize single-crystal diamond films. Bias-enhanced nucleation on iridium layers results in heteroepitaxial diamond films with highly improved alignment. By a subsequent textured-growth step, the mosaicity can be further reduced for tilt as well as for twist in sharp contrast to former experiments using silicon substrates. Minimum values of 0.17° and 0.38° have been measured for tilt and twist, respectively. Plan view transmission electron microscopy of these films shows that, for low thicknesses (0.6 μm and 8 μm), the films are polycrystalline, consisting of a closed network of grain boundaries. In contrast, at the highest thickness (34 μm) most of the remaining structural defects are concentrated in bands of limited extension. The absence of an interconnected network of grain boundaries shows that the latter films are no longer polycrystalline. © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Pure and applied geophysics 56 (1963), S. 150-158 
    ISSN: 1420-9136
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Summary Simultaneous measurements of wind, air temperature, and humidity profiles as well as of evaporation, presented byTakahashi (1958), were compared with relevant formulae suggested by turbulence theory. Satisfactory agreement could be achieved if, near the sea surface, the influence of molecular diffusion and, at higher levels, the effect of thermal stratification on the profiles were taken into account in addition to a suitable reduction of the value of evaporation obtained by means of a floating pan.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1432-0711
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Archives of gynecology and obstetrics 232 (1981), S. 736-737 
    ISSN: 1432-0711
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Archives of gynecology and obstetrics 214 (1973), S. 448-449 
    ISSN: 1432-0711
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0711
    Keywords: Gonadendysgenesie ; Östrogen- und Gestagen-Substitution ; Hypothalamus-Hypophysenfunktion ; Gonadal dysgenesis ; Estrogen-progestogen treatment ; Hypothalamo-pituitary function
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Summary We describe the plasma levels of FSH and LH in ten patients with gonadal dysgenesis during treatment with a low dosage sequential estrogen-progestogen preparation. The daily dose of mestranol ranged from 12.5–50 μg. Norethisterone was administered from day 16 onwards, the dose ranging between 0.75 and 1.5 mg. It was shown that 25 μg mestranol was effective in lowering the elevated FSH levels significantly (α 〈 0.001). LH levels remained unaffected. The combination of 25 μg mestranol and 1 mg norethisterone produced an increase of FSH and LH within 12 h, maximum levels being reached within 36 h after which there was a progressive decline. Low doses of estrogen and progestogen appeared capable of evoking physiological hypothalamic and pituitary responses in patients with gonadal dysgenesis. The doses employed were sufficient to induce breast development, growth of sexual hair, and withdrawal bleeding and were probably not high enough to induce rapid bone maturation and consequent stunting of growth.
    Notes: Zusammenfassung Die vorliegende Arbeit beschreibt das Verhalten der FSH- und LH-Plasmakonzentrationen bei zehn Patienten mit Gonadendysgenesie unter der Behandlung mit einem niedrig dosierten Sequenzpräparat. Die tägliche Mestranoldosis schwankt zwischen 12,5 und 50 μg im Sinne einer zyklusgerechten Substitution. In der zweiten Zyklushälfte ab dem 16. Tag wird Norethisteron in einer Dosis zwischen 0,75 und 1,5 mg verabfolgt. Dabei zeigt sich, daß 25 μg Mestranol die erhöhten FSH-Konzentrationen signifikant zu senken vermögen (α 〈 0.001). Zwölf Stunden nach der Gabe von 25 μg Mestranol + 1,0 mg Norethisteron wird ein signifikanter Anstieg der LH- und FSH-Plasmakonzentrationen mit einem Maximum am 18. Behandlungstag beobachtet. Danach kommt es dann zu einem progressiven Abfall der Gonadotropinspiegel im Plasma. Das hier vorgeschlagene Behandlungsschema mit Mestranol und Norethisteron führt bei der Gonadendysgenesie zu Veränderungen der Plasmagonadotropin-konzentrationen, die an den normalen ovulatorischen Zyklus erinnern. Die gewählte Dosis ist ausreichend zur Auslösung von Abbruchblutungen, zur Induktion der Brustentwicklung und zur Ausbildung der Achsel- und Schambehaarung. Die Dosis ist so niedrig gewählt, daß eine überstürzte Akzeleration der Knochenreifung nicht zu erwarten ist.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Archives of gynecology and obstetrics 219 (1975), S. 598-598 
    ISSN: 1432-0711
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Type of Medium: Electronic Resource
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