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  • 1
    Electronic Resource
    Electronic Resource
    Assessment of compositional disorder in AlxGa1−xAs superlattices from the analysis of Raman spectra (1991)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 59 (1991), S. 788-790 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: We present the calculation of the Raman spectra in backscattering configuration for AlxGa1−xAs (001) superlattices and modulated alloys, based on the bond-charge-model dynamics, the average t-matrix approximation for compositional disorder and the bond polarizability model for the Raman tensor. The features of Raman spectra are shown to reflect the Al concentration profile along the growth axis, hence providing a valuable tool for compositional characterization of superlattices.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.105343
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  • 2
    Electronic Resource
    Electronic Resource
    Time Trends in the Intracardiac Potential Recorded by Pacemaker Telemetry: Comparison Between Steroid-Eluting Small Area Electrodes (1999)
    Oxford, UK : Blackwell Publishing Ltd
    Pacing and clinical electrophysiology 22 (1999), S. 0 
    Details
    ISSN: 1540-8159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: We assessed the time course of electrograms sensed both in the atrium and ventricle by two different steroid-eluting electrodes: Medtronic Capsure SP (with an area of 5.5 mm2) and Z (with an area of 1.2 mm2). We considered 68 unipolar electrodes: 31 atrial (19 Capsure SP 4523 and 12 Capsure Z 4533) and 37 ventricular (24 Capsure SP 4023 and 13 Capsure Z 4033) implanted in 47 consecutive patients (30 men and 17 women, with an age of 72 ± 9.4 years). The pacemaker model was Medtronic Elite 7077–7086 (DDD-DDDR) in 25 patients and Medtronic Legend 8419–8424 (VVIR-AAIR) in 22 patients. The endocavitary signal (all patients had spontaneous rhythm) was telemetrically obtained by a Medtronic 9790 device and acquired on a personal computer at implantation and 7, 30, and 180 days thereafter. The signal was studied both in the time domain and in the frequency domain by spectral analysis. The following parameters were calculated: amplitude (A): peak-to-peak value of the complex; slew rate (SR) peak negative first derivative; F0: frequency at which the power spectrum reaches its maximum value; and bandwidth (Bw): expressed as the distance between the –3 dB points and statistically analyzed by a two-way analysis of variance with factors “time” (four measurements) and “electrode” (Capsure SP and Z) and repeated measurements on the former. Ventricular sensing: no time or electrode effect (P〉0.1 in all comparisons) was found for F0, Bw, or SR, while a time effect (P 〈 0.04) not dependent on the type of electrode was found for the amplitude of the signal. In particular, a significant increase was found between the measurement at 6 months and that at implantation (P 〈 0.004). Atrial sensing: A, F0, and bandwidth were not affected by time or electrode (P 〉 0.09), while SR behaved differently over time (P 〈 0.05) in the two electrodes (the Capsure Z showed an increase at sixth month [P 〈 0.04] compared to implantation). In conclusion, the Medtronic Capsure SP and Z electrodes proved to be valid and substantially equivalent as far as concerns the measurement of the intracardiac potential despite the difference between their surface areas. Further studies should be devised to assess whether transitory decreases of atrial Bw in the first month of follow-up observed in a few patients for both electrodes could be responsible for clinical episodes of sensing deficit.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1540-8159.1999.tb00596.x
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  • 3
    Electronic Resource
    Electronic Resource
    Electron tunneling spectroscopy on poly- and single crystalline Rb"3C"6"0
    Amsterdam : Elsevier
    Physica C: Superconductivity and its applications 235-240 (1994), S. 2499-2500 
    Details
    ISSN: 0921-4534
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0921-4534(94)92470-8
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  • 4
    Electronic Resource
    Electronic Resource
    Solid-state self-wetting phenomena at the (001) surface of semimetallic α-Ga
    Amsterdam : Elsevier
    Surface Science 307-309 (1994), S. 936-941 
    Details
    ISSN: 0039-6028
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/0039-6028(94)91519-9
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  • 5
    Electronic Resource
    Electronic Resource
    Reconstruction, disordering and roughening of metal surfaces
    Amsterdam : Elsevier
    Surface Science Reports 17 (1993), S. 363-422 
    Details
    ISSN: 0167-5729
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Physics
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/0167-5729(93)90019-L
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  • 6
    Electronic Resource
    Electronic Resource
    Evidence for a solid phase of dodecahedral C 20 (2003)
    Springer
    The European physical journal 31 (2003), S. 509-515 
    Details
    ISSN: 1434-6036
    Keywords: PACS. 61.48.+c Fullerenes and fullerene-related materials – 81.05.Tp Fullerenes and related materials – 61.50.Ah Theory of crystal structure, crystal symmetry; calculations and modeling – 81.07.Bc Nanocrystalline materials – 81.15.Fg Laser deposition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: Evidence is presented for the formation of a solid phase based on the smallest fullerene, C20, in thin diamond-like carbon films deposited by ultraviolet laser ablation from diamond onto nickel substrates at room temperature in the presence of 10-4 torr of cyclohexane or benzene. Laser desorption mass spectrometry from the films shows the presence of C20, C21 and C22 species, while micro-Raman spectroscopy and electron diffraction from selected particles together with first principle density-functional calculations, indicate a cubic solid with dodecahedral C20 cages as building blocks. Unlike solid C60 and fully protonated C20, which are bound by van der Waals forces, the proposed structure is stabilized by linking of the C20 dodecahedra with bridging carbon atoms at interstitial tetrahedral sites to form a face-centered-cubic lattice with 22 carbon atoms per unit cell.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjb/e2003-00060-4
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  • 7
    Electronic Resource
    Electronic Resource
    Electron-phonon interaction in carbon schwarzites (2003)
    Springer
    The European physical journal 32 (2003), S. 181-187 
    Details
    ISSN: 1434-6036
    Keywords: PACS. 71.15.Mb Density functional theory, local density approximation, gradient and other corrections – 74.70.Wz Fullerenes and related materials – 74.10.+v Occurrence, potential candidates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract: The recent synthesis of random schwarzites has stimulated the present ab initio calculation of the electronic structure and electron-phonon interaction in two different periodic D-type schwarzites, fcc-(C28)2 (made of 24 seven-membered rings per unit cell) and fcc-(C64)2 (made of 12 eight membered and 48 six-membered rings per unit cell). Like in fullerenes, also in schwarzites the electron-phonon interaction potential is found to increase with the absolute Gauss curvature, though it remains smaller than for doped fullerenes.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjb/e2003-00087-5
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  • 8
    Electronic Resource
    Electronic Resource
    Electron-phonon interaction in carbon clathrate hex- $\mathsf{C_{40}}$ (2003)
    Springer
    The European physical journal 34 (2003), S. 63-67 
    Details
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The electron-phonon interaction in Li-doped carbon clathrates hex-LiC40 and hex-Li2C40 has been investigated from first principles. Although the characteristic phonon frequency and electron-phonon interaction are large, the electronic density of states is relatively low which finally gives an electron-phonon coupling constant $\lambda = 0.46$ for Li2C40. Hole-doping is expected to provide higher Tc than n-doping in hex-C40.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjb/e2003-00197-0
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  • 9
    Electronic Resource
    Electronic Resource
    Ab initio phonon dispersion relations of $\mathsf{\alpha}$ -Ga (2003)
    Springer
    The European physical journal 36 (2003), S. 87-90 
    Details
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. We present the ab initio phonon dispersion relations of $\alpha$ -Ga. The calculations are carried out within density functional perturbation theory by using either norm-conserving pseudopotential and 4s and 4p electrons in the valence or ultrasoft pseudopotential and 3d electrons in the valence as well. The inclusion of 3d electrons in the valence turned out to be necessary to better reproduce the experimental frequencies of the stretching modes of the Ga2 dimers present in the $\alpha$ -Ga structure.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjb/e2003-00320-3
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  • 10
    Electronic Resource
    Electronic Resource
    Vibrational properties of C $\mathsf{_{20}}$ -based solids (2003)
    Springer
    The European physical journal 37 (2003), S. 143-148 
    Details
    ISSN: 1434-6036
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract. The phonon dispersion relations and IR spectrum of a C20-based solid recently identified experimentally [Iqbal et al. , Eur. Phys. J. B 31, 509 (2003)] have been computed by density functional perturbation theory. Other competitive structures made by assembling C20 clusters have been considered as well. In particular, we have computed the structure and the Raman spectra of two-dimensional polymeric phases of hydrogenated C20 clusters which might be formed under different synthesis conditions. Fingerprints of the different phases have been identified in the vibrational spectra which could be used in the experimental search of C20-based solids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1140/epjb/e2004-00040-2
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