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  • 1
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Advanced materials research Vol. 59 (Dec. 2008), p. 304-307 
    ISSN: 1662-8985
    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
    Notes: The mechanical properties of Fe-Cr alloys were investigated in as-grown and in post-ion-implanted conditions. Sets of specimens were produced using dual implantations of Fe+ ions to give 1µm deep damaged layers with average damage levels of 0.35 displacements per atom and 5.33 displacements per atom. Nanoindentation was used to measure hardness as a function of depth and showed that implanted material had a higher hardness than unimplanted material. Additionally, micron-scale cantilevers were fabricated from the ion-damaged surface of the material and were tested using a nanoindenter for AFM-imaging and loading. The mechanical properties deduced from the controlled loading of these cantilevers pertain only to radiation-damaged material, and for the high-dose material show significant changes in Young’s modulus, yield stress and work-hardening
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 108-109 (Dec. 2005), p. 139-144 
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Notes: Dislocation locking by nitrogen impurities has been investigated in float-zone silicon with nitrogen concentrations of 2.2 x 1015cm-3 and 3 x 1014cm-3. The stress required to unlock dislocations pinned by nitrogen impurities was measured as a function of annealing time (0 to 2500 hours) and temperature (550 to 830ºC). For all conditions investigated the locking effect was found to increase linearly with annealing time before saturating. It is assumed that the rate of increase of unlocking stress with annealing time is a measure of transport of nitrogen to the dislocation core. This rate of increase was found to depend linearly on nitrogen concentration, which is consistent with transport by a dimeric species, whose activation energy for diffusion is approximately 1.4eV. The saturation unlocking stress has been found to be dependent on the nitrogen concentration. Additionally, the temperature dependence of the stress required to move dislocations immobilised by nitrogen impurities has been studied. By assuming a value for the binding energy of the nitrogen to the dislocation, the density of the locking species at the dislocation core has been calculated
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Industrial & engineering chemistry research 28 (1989), S. 1725-1730 
    ISSN: 1520-5045
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    350 Main Street , Malden , MA 02148-5018 , USA and 9600 Garsington Road , Oxford OX4 2DQ , UK . : Blackwell Science Inc
    Pacing and clinical electrophysiology 27 (2004), S. 0 
    ISSN: 1540-8159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The purpose of the study was to investigate the results of endocardial lead implantation, lead performance, and follow-up in young patients after the Fontan procedure. A retrospective study was conducted with patients who had endocardial atrial pacing for SND and intact AVN function after Fontan from two pediatric centers. Patient demographics, pacing, and sensing data of endocardial atrial leads were analyzed at the time of pacemaker implantation and follow-up visits. Fifteen patients (weight 42.6 ± 35 kg) had transvenous endocardial atrial lead implantation at an average age of 11.4 ± 6.5 years. Active-fixation leads were used in all patients and steroid elution was present in 12 (80%) patients. Adequate P wave sensing was obtained in patients with sinus rhythm (n = 10); the remaining four patients had junctional rhythm without measurable P waves. Lead failure was not observed in any patient during the follow-up period of 2.9 ± 2.1 years. The energy threshold at implantation was 1.46 ± 1.5 μJ, 1.54 ± 0.75 μJ at 3 months, 0.62 ± 0.45 μJ at 1 year, 0.72 ± 0.65 μJ at 2 years, 0.75 ± 0.55 μJ at 3 years, and 0.8 ± 0.85 μJ at 5 years postimplant. The lead impedance was 648 ± 298 Ω at implantation, 714 ± 163 Ω at 3 months, 744 ± 195 Ω at 1 year, 734 ± 198 Ω at 2 years, 800 ± 142 Ω at 3 years and 830 ± 200 Ω 5 years postimplant. Anticoagulation therapy (aspirin n = 5, warfarin n = 8) was continued by 13 patients. Complications consisted of a pneumothorax at implantation and a transient ischemic attack in one patient 4 years after pacemaker implant. Endocardial atrial leads offer low energy thresholds and can be implanted relatively safely in Fontan patients. (PACE 2004; 27:949–954)
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-1971
    Keywords: Hypoplastic left heart syndrome ; Cardiovascular surgery
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary To determine whether preoperative demographic and metabolic variables correlated with early or late survival following palliative surgery for hypoplastic left heart syndrome, we reviewed the charts of 89 patients operated upon from October 1984 to January 1987. The variables analyzed were age at operation, lowest preoperative pH and H2CO3, highest preoperative arterial oxygen saturation, the occurrence of a preoperative cardiorespiratory arrest, and location of birth relative to the surgical institution. The data were evaluated by chi-squared, multivariate, and life-table analyses to the end of the first postoperative year. None of the factors analyzed significantly correlated with either short-term (≤30 days) or long-term (〉30 days) survival. Thus, neither demographic nor metabolic factors including prior cardiorespiratory arrest should be considered contraindications to surgical palliation for hypoplastic left heart syndrome.
    Type of Medium: Electronic Resource
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