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  • 1
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 80 (2002), S. 1249-1251 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: The optical properties of a set of high-k dielectric HfO2 films annealed at various high temperatures were determined by spectroscopic ellipsometry. The results show that the characteristics of the dielectric functions of these films are strongly affected by high temperature annealing. For a sample annealed at 600 °C, the film becomes polycrystalline, and its dielectric function displays a distinctive peak at 5.9 eV. On the other hand, the film remains amorphous without the 5.9 eV feature after 500 °C annealing. To model the dielectric functions, the Tauc–Lorentz dispersion was successfully adopted for these amorphous and polycrystalline films. The absorption edge was observed to shift to a higher energy at a high temperature annealing. Defects in the films were shown to relate to the appearance of a band tail above the absorption edge, and they appear to diminish with high temperature annealing. © 2002 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 77 (2000), S. 3012-3014 
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Postdeposition annealing of high-k dielectric Ta2O5 films to eliminate contaminations can adversely cause the films to crystallize, which can be detrimental to their complementary metal–oxide–semiconductor device performances. In this letter, we will show that spectroscopic ellipsometry can be used to quickly and nondestructively detect such crystallization by identifying the two relatively sharp absorption peaks at 4.7 and 5.2 eV in the complex dielectric function of the films. Such peaks are absent in amorphous Ta2O5 films. In general, these sharp structures in the dielectric function are expected from the presence of long-range order in materials, which produces singularities in their interband density of states. Using this approach, we will show that Ta2O5 films become crystalline when annealed at or above 750 °C and remain amorphous below 700 °C. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Human genetics 〈Berlin〉 4 (1967), S. 294-304 
    ISSN: 1432-1203
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The crying of one baby (girl) with a cri du chat-syndrome and another baby (boy) with a similar voice, but without the typical B-chromosome deficiency, were analysed by acoustic methods. The particular physical qualities of the voices were compared to those of normal infants. The typical cry of the girl is different from normal cries in the following characteristics: 1. in the pitch (nearly one octave higher, 600 ... 900 Hz), 2. in a monotonous melody curve, which means a lack of expression in its sound character, 3. in the vocalic sound character similar to singing the vowel “e”, and in the absence of random noise in the frequency spectrum. The cry of the boy suspected to have the cri du chat-syndrome also had these qualities, but only in certain parts of his crying. The acoustic analysis show some important differences in the crying of these two babies: the girl with the cri du chat-syndrome can cry only in her typical way. The boy changes the character of his crying as soon as he is offended. Then the cry becomes normal in all qualities with exception of a higher frequency. The course of melody, a periodicity with falling frequency at the end of each single cry and the share of random noise give the cry an expression like that of a normal baby. Further acoustic analyses are necessary, especially of infants with cri du chat-like crying who are supposed to have a specific cerebral defect. Some ideas as to the pathogenesis of the typical cri du chat of babies with the syndrome are discussed. Our results show that it is caused by an organic or functional cerebral lesion and not by a malformation of the voice giving organs. Addendum: After the manuscript was submitted the paper of V. Vuorenkoski et al. was brought to our attention. Thier results regarding the typical features of cries from babies with the syndrome are in agreement with our findings. This also confirms our suggestion that special analysis of cries may serve to exclude clinical similar cases with different etiology.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-1084
    Keywords: Renal artery obstruction ; Magnetic resonance ; Blood flow velocity ; Hypertension, renal
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Three-dimensional (3D) phase-contrast magnetic resonance angiography (MRA) and velocity-encoded cine magnetic resonance (VEC-MR) imaging were performed in 23 subjects to assess the severity of renal artery stenosis. MRA was used for detection of stenosis, demonstrating a sensitivity of 100% and a specificity of 80%; the severity of stenosis was overestimated in 33%. VEC-MR was used to quantify the renal flow oattern and was successful in 11 subjects. Mean blood flow of normal renal arteries (420 +- 107 ml/min) was significantly higher (P 〈 0.01) than mean blood flow of stenotic arteries (131 +- 46ml/min). The flow profile displayed both systolic and diastolic peaks in 75% of the normal arteries, while the flow in stenotic arteries showed only a single systolic peak in all cases. The systolic peak in stenotic arteries occurred significantly later (32 +- 3% of the period of one cardiac cycle) than in normal subjects (21 +- 7%) (P 〈 0.05). Phase-contrast MR is likely to gain considerable importance in the noninvasive aetection and quantification of renal artery stenosis.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Polar biology 14 (1994), S. 491-503 
    ISSN: 1432-2056
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During a pilot study in June 1991 meso-and macrozooplankton investigations were carried out in the region of the Northeast Water (NEW), a polynya located off Northeast Greenland at about 80°N. The mesozooplankton collected by bongo net was dominated by the large herbivorous copepods Calanus glacialis, C. hyperboreus and C. finmarchicus. At most stations the Calanus populations consisted of overwintering stages, except for an ice-free site in the northwestern corner of the study area, where young copepodids of C. hyperboreus and C. glacialis occurred. Young C. finmarchicus were only found at stations influenced by Atlantic water masses, whereas C. glacialis was the prevailing species on the East Greenland shelf. Egg production of this species was variable, but spawning activity appeared to be related to ambient chlorophyll a concentrations. Carbon requirements of herbivorous Zooplankton were estimated from egg production rates of C. glacialis. Due to low mesoplankton biomass, a mean of only 10% (ranging from 〈1% to 53%) of the phytoplankton carbon were grazed. Macrozooplankton was collected at three stations by a Rectangular Midwater Trawl (RMT 1+8). Major components were chaetognaths, hyperiid amphipods and large copepods. Macroplankton biomass was extremely low (1–3 mg AFDW m−3), about one order of magnitude less than that of the mesoplankton. Based on these limited data we hypothesize that macroplankton plays only a minor role as food for higher trophic levels and as predators controlling mesoplankton in the NEW polynya. These findings seem todisprove the concept of a rich pelagic community in the polynya amongst “a desert of ice”. They do, however, fit well with the notion of strong pelago-benthic coupling of primary production supporting a rich benthos within the polynya area.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1434-6036
    Keywords: PACS. 61.10.Ht X-ray absorption spectroscopy: EXAFS, NEXAFS, XANES, etc. – 68.35.Fx Diffusion; interface formation – 75.70.Ak Magnetic properties of monolayers and thin films – 82.80.Pv Electron spectroscopy (X-ray photoelectron (XPS), Auger electron spectroscopy (AES), etc.)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: Interface reaction and magnetism of epitaxially-grown Fe on InAs(100) are studied by core-level photoemission (As 3d and In 4d) and Fe 2p X-ray magnetic circular dichroism using synchrotron radiation. The reactivity of Fe/InAs(100) is relatively low compared to that of other interfaces involving deposition of 3d metals on III-V semiconductors. As a consequence, we observe a magnetic signal at Fe L2, 3 edges for the lowest thicknesses studied (1 ML). The atomic magnetic moment reaches a value close to that of the bulk α-Fe (2.2 μ B) for Fe coverages exceeding 5 ML. A ferromagnetic compound with approximate stoichiometry of FeAs is formed at the interface. The orbital magnetism represents between 12 and 20% of the total momentum, due to 3d density of states depletion and to crystal-field modification of the electronic levels. These properties make the Fe/InAs(100) interface very promising for spin-tunneling devices.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Springer
    Journal of optimization theory and applications 73 (1992), S. 465-499 
    ISSN: 1573-2878
    Keywords: Nonlinear programming algorithms ; locally superlinearly convergent methods ; globally convergent methods ; hybrid techniques
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract With reference to smooth nonlinearly constrained optimization problems, we consider combinations of locally superlinearly convergent methods with globally convergent ones. The aim of this paper is threefold: to give a survey on well-known as well as possible unknown hybrid optimization methods, based on a special construction principle; to present a general convergence result for the class of hybrid algorithms; and to derive further methods for this class with new convergence properties.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 1434-6079
    Keywords: 34.70
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract We report new experimental data for the investigation of the role of electronic orbital alignment and orientation in charge transfer processes, in the medium energy range where the collision velocityv c and the velocity of the active electronv e are of the same order of magnitude. The results obtained for the H 2 + -Na(3p) and He+-Na(3p) collisions are discussed in comparison with the experimental and theoretical findings obtained for the H+-Na(3p) system. Recent time-of-flight measurements for charge transfer in Li+-Na(3s and 3p) collisions are also presented.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Springer
    The European physical journal 18 (1991), S. 231-234 
    ISSN: 1434-6079
    Keywords: 34.00 ; 34.70 ; 32.80
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract Neutralisation processes in 0.15–1.5 keV collisions of H− with Na atoms in the 3s ground state or in the excited 3p state have been investigated by means of time-of-flight analysis of the neutral H atoms produced. The H− - Na(3p) system, investigated here for the first time, is particularly interesting since the entrance channel is embedded in the [H - Na(3s)] +e − continuum, enabling Penning detachment to occur. The measured relative neutralisation cross section ratios σ(3p)/σ(3s) decrease from 3 to 1.6 with increasing energy. Based on earlier published results for σ(3s), σ(3p) total cross sections exceeding 100 Å2 are estimated.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Fresenius' Zeitschrift für analytische Chemie 341 (1991), S. 31-34 
    ISSN: 1618-2650
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary During bombardment of Ga1−xAlxAs and GaAs with oxygen we found an abrupt transition to higher sputter rates, change of the useful yield and significant increase of surface roughness at a well defined depth, which is essentially deeper than the penetration depth of the primary ions. Using oxygen and cesium as primary ions ‘varying’ energy and angle of incidence, residual gas pressure and matrix composition their effects on the phenomena were investigated. Although some remarkable properties of the sample modification process could be found, no theoretical description can be given up to now.
    Type of Medium: Electronic Resource
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