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  • 1
    Electronic Resource
    Electronic Resource
    Semiconducting iron disilicide films on Si(111): A high resolution electron energy loss spectroscopy study (1992)
    [S.l.] : American Institute of Physics (AIP)
    Journal of Applied Physics 72 (1992), S. 5905-5911 
    Details
    ISSN: 1089-7550
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Thin films of β-FeSi2 on Si(111) have been studied by low energy electron diffraction (LEED) and high resolution electron energy loss spectroscopy (HREELS). The observed LEED pattern is consistent with two possible epitaxial orientations. HREELS measurements demonstrate the semiconducting character of the films. The energy gap is determined to Eg(approximately-equal-to)0.92 eV–0.33 meV/K T(K). Additionally a number of optical phonons is found in the range between 200 and 500 cm−1. Theoretical spectra are calculated with optical phonon parameters obtained from infrared data and are compared with the measured spectra.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.351898
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    An electron–nuclear double resonance study of the lowest triplet state of pyrimidine (1992)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 97 (1992), S. 99-109 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Optically-detected electron–nuclear double resonance was employed to measure the entire hyperfine and quadrupole tensors of the two nitrogen nuclei and the hyperfine tensors of the four hydrogen nuclei in the lowest triplet state T0 of pyrimidine-h4 as a guest in a single crystal of benzene-d6. The electron-spin-density distribution and the molecular geometry in the lowest triplet state have been determined as well as the orientation of the molecule in the benzene crystal. It is found that upon excitation into T0, pyrimidine remains a planar molecule of approximately C2v symmetry; the C–N–C angles, which are 115.5° in the ground state, and the angle between the directions of the nonbonding nitrogen orbitals both become 〉120°. Nearly 60% of the total electron-spin density is located at the two nitrogen atoms, the two nonbonding orbitals each carrying a spin density of 0.21, and the π orbitals a spin density of 0.08. We conclude that the lowest triplet state of pyrimidine is appropriately described in terms of an nπ* excitation; we find no evidence for vibronic coupling of this state with higher lying 3ππ* states.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.463529
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  • 3
    Electronic Resource
    Electronic Resource
    An electron–nuclear double resonance study of the lowest triplet state of pyrazine (1992)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 97 (1992), S. 110-117 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: The hyperfine and quadrupole tensors of the two nitrogen atoms and the hyperfine tensors of the four hydrogen atoms of pyrazine in the lowest triplet state T0 are obtained from optically-detected electron–nuclear double resonance (ENDOR) experiments on pyrazine-h4 in a single crystal of benzene-d6 at 1.2 K. Analysis of these tensors shows that pyrazine is in good approximation a planar molecule of D2h symmetry in the lowest triplet state. The in-plane structure changes significantly upon excitation into T0. An increase of the C–N–C angles is observed and a reduction of the C–N bond lengths. From the hyperfine tensors the distribution of the electron-spin density is derived. The nitrogen nonbonding orbitals together carry 36% of the total spin density and it is shown that the lowest triplet state of pyrazine is appropriately described in terms of a 3nπ* excitation. The results of the optically-detected ENDOR experiments give no indication of vibronic coupling of the lowest 3nπ* state with nearby 3ππ* states.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.463609
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  • 4
    Electronic Resource
    Electronic Resource
    Co/Ag multilayer film: Role of annealing on the magnetic properties (1992)
    Woodbury, NY : American Institute of Physics (AIP)
    Applied Physics Letters 61 (1992), S. 1858-1860 
    Details
    ISSN: 1077-3118
    Source: AIP Digital Archive
    Topics: Physics
    Notes: Co(15 A(ring))/Ag(60 A(ring)) multilayers produced by electron beam deposition on a 50 A(ring) chromium buffer layer over a Si(111) wafer have been studied by magnetoresistance, saturation magnetization, coercivity, and anisotropy. Annealing at various temperatures produces striking effects on the observed physical properties, such as an improvement on the value of the magnetoresistance associated to a "back-diffusion'' process in the Co/Ag interfaces. This leads one to believe that interface roughness is indeed most important to understanding the connection between giant magnetoresistance and antiferromagnetic coupling, as well as the behavior of coercivity vs interface anisotropy in these materials.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.108397
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  • 5
    Electronic Resource
    Electronic Resource
    Unconstrained duals to partially separable constrained programs (1992)
    Springer
    Mathematical programming 56 (1992), S. 337-341 
    Details
    ISSN: 1436-4646
    Keywords: 90C25 ; 65K05 ; Lagrange dualization ; existence theorems ; numerical aspects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science , Mathematics
    Notes: Abstract In this note partially separable convex programs are dualized in such a way that, under certain assumptions, unconstrained concave duals arise. A return formula is given by which the solution of the primal is directly computed if a solution of the dual is known. Further, the solvability of both the primal and the dual is shown to depend essentially on the behaviour of the lower dimensional programs for determining the Fenchel conjugates.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01580906
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  • 6
    Electronic Resource
    Electronic Resource
    Constrained smoothing of histograms by quadratic splines (1992)
    Springer
    Computing 48 (1992), S. 97-107 
    Details
    ISSN: 1436-5057
    Keywords: 65D10 ; 41A15 ; 90C25 ; FunctionalsK 2 andK ∞, constraints like convexity or monotonicity ; linear programs ; partially separable programs and dualization ; Fenchel conjugates
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Zum Glätten von Histogrammen unter Nebendedingungen wie Konvexität oder Monotonie werden die ZielfunktionaleK 2 undK ∞ vorgeschlagen, welche dem bekannten Schoenberg-Funktional von der Datenglättung nachgebildet sind. Bei Verwendung von quadratischen Splines erhält man strukturierte, endlichdimensionale Optimierungsaufgaben. Auftretende partiell separable, konvexe Aufgaben können durch Dualisierung einer effektiven numerischen Behandlung zugeführt werden.
    Notes: Abstract For smoothing histograms under constraints like convexity or monotonicity, in this paper the functionalsK 2 andK ∞ are proposed which can be considered as extensions of the Schoenberg functional known from data smoothing. When using quadratic splines we are led to structured finite dimensional programming problems. Occuring partially separable convex programs can be solved effectively via dualization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02241708
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  • 7
    Electronic Resource
    Electronic Resource
    Positive, monotone, andS-convexC 1-interpolation on rectangular grids (1992)
    Springer
    Computing 48 (1992), S. 363-371 
    Details
    ISSN: 1436-5057
    Keywords: 65 D 07 ; 41 A 15 ; 41 A 63 ; Shape preservingC 1-interpolation ; special rational biquadratic splines ; construction by a search procedure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Computer Science
    Description / Table of Contents: Zusammenfassung Diese Arbeit befaßt sich mit formerhaltenderC 1-Interpolation von Daten auf Rechteckgittern. Bei Verwendung von speziellen rational-biquadratischen Splines werden Bedingungen hergeleitet, welche hinreichend für die Positität, Monotonie undS-Konvexität sind und welche sich darüber hinaus erfüllen lassen, sofern die Rationalitätsparameter hinreichend groß sind.
    Notes: Abstract This paper is concerned with shape preservingC 1-interpolation of data sets given on rectangular grids. Using special rational biquadratic splines, criteria are derived which are sufficient for the positivity, monotonicity, andS-convexity and which, in addition, are satisfied for sufficiently large rationality parameters.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02238643
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  • 8
    Electronic Resource
    Electronic Resource
    Intra-articular injections and articular cartilage metabolism (1992)
    Springer
    Archives of orthopaedic and trauma surgery 111 (1992), S. 237-242 
    Details
    ISSN: 1434-3916
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary We studied the effects of repeated intra-articular injections of sterile 140 mM NaCl solution on articular cartilage in adult rabbits. After 20 injections into the knee joints over a period of 4 weeks, chondrocyte glucosaminoglycan synthesis was evenly reduced in all cartilage layers, accompanied by a significant proteoglycan depletion of the matrix which was most marked in the superficial half of the cartilage. These and other changes only partially reversed during a further 4-week period after the injections had been stopped. Our data underline the need for a clear-cut indication for intra-articular injections. The microtrauma caused by injection, in conjunction with the introduction of a carrier solution into the joint, may, at least when repeated at short intervals, lead to measurable damage to the articular cartilage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00571486
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  • 9
    Electronic Resource
    Electronic Resource
    The effect of ketanserin on cerebral blood flow and cerebrovascular CO2 reactivity in healthy volunteers (1992)
    Springer
    Acta neurochirurgica 119 (1992), S. 7-11 
    Details
    ISSN: 0942-0940
    Keywords: Carbon dioxide ; cerebral blood flow ; cerebral oxygen metabolism ; cerebral vascular reactivity ; ketanserin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The effect of the anti-hypertensive agent ketanserin on the cerebral blood flow (CBF) and the cerebrovascular CO2 reactivity was examined in 10 healthy volunteers. Ketanserin was administered as an intravenous bolus of 10 mg followed by an infusion of 6mg/h. Before administration CBF was measured by single photon emission computerized tomography (SPECT) of inhaled133 Xenon. Then arterial CO2 tension was subsequently decreased by voluntary hyperventilation and increased by breathing an air/CO2 mixture. The relative changes in CBF induced by the changes in arterial CO2 tension were estimated by the cerebral arterio-venous oxygen content difference method. One hour following the start of ketanserin infusion the SPECT measurement and CO2 manipulations were repeated. The CO2 reactivity (expressed as the slope of the regression line of the linear relation between CBF and PaCO2), was unchanged, i.e. 3.2%/0.1 kPa before ketanserin and 4. 1%/0.1 kPa during ketanserin, respectively. Using regression lines from a semi-logarithmic plot the CO2 reactivity was also unchanged 3.4%/0.1 kPa and 3.5%/0.1 kPa, respectively. Ketanserin did not change CBF. The cerebral oxygen metabolism (CMRO2) was decreased 19% one hour after the start of infusion of ketanserin. In conclusion administration of ketanserin in a clinically relevant dose to healthy volunteers does not change the regional CBF not the cerebrovascular CO2 reactivity, but a decrease in CMRO2 was observed. However further studies are needed to clarify whether ketanserin in fact has a depressing effect on CMRO2 or whether the different results are caused by methodological errors or stocastic variation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01541774
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  • 10
    Electronic Resource
    Electronic Resource
    Magnetic Resonance from a Metastable Sulfur-Pair-Related Complex Defect in Silicon (1992)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 83-87 (Jan. 1992), p. 251-256 
    Details
    ISSN: 1662-9752
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/21/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.83-87.251.pdf
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