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  • 2005-2009  (20)
  • 1
    Electronic Resource
    Electronic Resource
    Computer Modelling of Oxygen Mobility at Ceria Surfaces and the Construction of Ceria Nanotube Models (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Advances in science and technology Vol. 46 (Oct. 2006), p. 48-53 
    Details
    ISSN: 1662-0356
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Natural Sciences in General , Technology
    Notes: The aim of this paper is to describe the recent progress in using atomisticsimulation techniques to develop simulation models of ceria nanotubes and to modeloxygen ion transport at ceria surfaces. The basis of these atomistic techniques is to usethe Born Model of Solids where parameterized analytical equations are employed todescribe the interactions between atoms. Once these interatomic forces are specifiedenergy minimization and molecular dynamics techniques can be applied to the models
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/42/transtech_doi~10.4028%252Fwww.scientific.net%252FAST.46.48.pdf
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  • 2
    Electronic Resource
    Electronic Resource
    Single Crystal Growth – New Techniques on Old Base (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 508 (Mar. 2006), p. 479-484 
    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
    Notes: The progress in advanced single crystal growth demands versatile, advanced equipment. Multizone furnaces are able to fulfill unusual technological requirements providing versatile and reliable all-in-one tools for laboratories on the ground or in space. The concept of the Universal Multizone Crystallizator (UMC), its hardware and software components along with several application examples are demonstrated
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/12/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.508.479.pdf
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  • 3
    Electronic Resource
    Electronic Resource
    Diffusion Controlled Abnormal Grain Growth in Ceramics (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 558-559 (Oct. 2007), p. 1227-1236 
    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
    Notes: The grain growth kinetics of silica and calcia doped alumina at 1400oC and their grainboundary complexion is characterized. These data are compared to predictions of both diffusioncontrolled and nucleation limited interface controlled grain growth theory. It is deduced from theindicators that the mechanism for normal and abnormal grain growth in these aluminas is diffusioncontrolled
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/17/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.558-559.1227.pdf
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  • 4
    Electronic Resource
    Electronic Resource
    High-Temperature Operation of 50 A (1600 A/cm〈sup〉2〈/sup〉), 600 V 4H-SiC Vertical-Channel JFETs for High-Power Applications (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 600-603 (Sept. 2008), p. 1055-1058 
    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
    Notes: In this work we have demonstrated the high-temperature operations of 600 V/50 A 4HSiCvertical-channel junction field-effect transistors (VJFETs) with an active area of 3 mm2.Specific-on resistance (RONSP) in the linear region of a single die is less than 2.6 mW.cm2 while thedrain-source current is over 50 A under a gate bias (VGS) of 3 V. A reverse blocking gain of 54 isobtained at gate bias ranging from -13 V to -23 V and drain-source leakage current (IRDS) of 200 μA.To demonstrate the use of SiC VJFETs for high-power applications, eight 3 mm2 SiC VJFETs arebonded in a high current 600-V module. RONSP in the linear region of these eight-paralleled SiCVJFETs is 2.8 mW.cm2 at room temperature and increased to 5.35 mW.cm2 at an ambienttemperature of 175 °C in air, corresponding to a shift of 0.61%/°C from room temperature to 175 °C.Meanwhile, the forward current is over 360 A at room temperature and reduces to 188 A at 175 °Cat drain-source bias (VDS) of 5.25 V and VGS of 3 V
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/20/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.600-603.1055.pdf
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  • 5
    Electronic Resource
    Electronic Resource
    High-Temperature Static and Dynamic Reliability Study of 4H-SiC Vertical-Channel JFETs for High-Power System Applications (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 600-603 (Sept. 2008), p. 1051-1054 
    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
    Notes: In this work we report the most recent high-temperature long-term reliability results ofthe 600 V/14 A, 4H-SiC vertical-channel junction field-effect transistors (VJFETs). Two groups (Aand B) devices were subjected to different thermal and electrical stresses. One device (Group A)reached 12,000 hours of continuous switching without a single failure. Four devices in Group Awere thermally stressed at 250 °C over 4,670 hours in air, for which standard deviation of thespecific on-resistance (RONSP) in linear region at gate bias (VGS) of 3 V were 〈 4.1% throughout theentire duration time. The off-state characteristics were evaluated by high temperature reverse bias(HTRB) tests. Three devices (Group A) were biased at 50% rated BVDS at 250 °C for 2,278 hours.A higher reverse bias at 80 % rated BVDS was then applied to 14 devices (group B) at 200 °C for1,000 hours. Variations of the leakage current were negligible throughout the entire HTRB test forall tested devices
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/20/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.600-603.1051.pdf
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  • 6
    Electronic Resource
    Electronic Resource
    The nematode Panagrellus redivivus is susceptible to killing by human pathogens at 37 °C (2005)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 250 (2005), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Caenorhabditis elegans has been used as a host for the study of bacteria that cause disease in mammals. However, a significant limitation of the model is that C. elegans is not viable at 37 °C. We report that the gonochoristic nematode Panagrellus redivivus survives at 37 °C and maintains its life cycle at temperatures up to and including 31.5 °C. The C. elegans pathogens Pseudomonas aeruginosa, Salmonella enterica, Staphylococcus aureus, but not Yersinia pseudotuberculosis, reduced P. redivivus lifespan. Of four strains of Burkholderia multivorans tested, one reduced P. redivivus lifespan at both temperatures, one was avirulent at both temperatures and two strains reduced P. redivivus lifespan only at 37 °C. The mechanism by which one of these strains killed P. redivivus at 37 °C, but not at 25 °C, was investigated further. Killing required viable bacteria, did not involve bacterial invasion of tissues, is unlikely to be due to a diffusible, bacterial toxin and was not associated with increased numbers of live bacteria within the intestine of the worm. We believe B. multivorans may kill P. redivivus by a temperature-regulated mechanism similar to B. pseudomallei killing of C. elegans.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1016/j.femsle.2005.06.046
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    Paper (German National Licenses)
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  • 7
    Electronic Resource
    Electronic Resource
    Was this guide helpful? Users' perceptions of subject guides (2005)
    Bradford : Emerald
    Reference services review 33 (2005), S. 188-196 
    Details
    ISSN: 0090-7324
    Source: Emerald Fulltext Archive Database 1994-2005
    Topics: Information Science and Librarianship
    Notes: Purpose - Most academic libraries make subject or research guides available on their web sites. Little is known, however, in terms of user satisfaction with guides. This study examines methods used to evaluate guides and reports on an online survey placed on each of more than 80 web-based guides provided by Gelman Library, George Washington University. Design/methodology/approach - The survey, borrowing an approach used by Amazon.com and other web sites, consisted of a single question - Was this guide useful - and a comments box. Findings - Two hundred ten responses were received during Fall semester 2003. Fifty two percent of responses rated guides as Very Helpful or Somewhat Helpful, while 40 percent gave ratings of Not Helpful or a Little Helpful. Originality/value - Although limited in scope, this simple survey revealed positive elements of the guides and identified problems that could be addressed immediately. The survey also helped to identify larger issues that will benefit from additional user input.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1108/00907320510597381
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  • 8
    Electronic Resource
    Electronic Resource
    Differences in Outcomes Between Patients Treated with Single- versus Dual-Chamber Implantable Cardioverter Defibrillators: A Substudy of the Multicenter Automatic Defibrillator Implantation Trial II (2005)
    350 Main Street , Malden , MA 02148 , USA , and 9600 Garsington Road , Oxford OX4 2XG , UK . : Blackwell Publishing, Inc.
    Annals of noninvasive electrocardiology 10 (2005), S. 0 
    Details
    ISSN: 1542-474X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Objectives: We sought to evaluate the influence of single- versus dual-chamber implantable cardioverter defibrillators (ICDs) on the occurrence of heart failure and mortality as well as appropriate and inappropriate ICD therapy in the Multicenter Automatic Defibrillator Implantation Trial II (MADIT-II). Background: In MADIT-II, ICD therapy in patients with a prior myocardial infarction and ejection fraction ≤0.30 was associated with a 31% reduction in risk of mortality when compared to conventionally treated patients. An unexpected finding was an increased occurrence of hospitalization for heart failure in the ICD group. Methods: Data from 717 patients randomized to ICD therapy with single- or dual-chamber pacing devices in MADIT-II were retrospectively analyzed. Endpoints selected for analysis included death from any cause, new or worsening heart failure requiring hospitalization, death or heart failure, appropriate therapy for ventricular tachycardia (VT) or ventricular fibrillation (VF), and inappropriate ICD therapy for atrial fibrillation or supraventricular tachycardia. Results: A total of 404 single-chamber ICDs (S-ICDs) and 313 dual-chamber ICDs (D-ICDs) were implanted. Patients receiving D-ICDs were at a higher risk at baseline than those receiving S-ICDs, with older age, higher NYHA class, more frequent prior CABG, wider QRS complex, more LBBB, higher BUN level, a history of more atrial arrhythmias requiring treatment, and a longer time interval from their index myocardial infarction to enrollment. While there was a trend toward an increase in adverse outcomes in the D-ICD group, no statistically significant differences in heart failure or mortality were observed between S-ICD versus D-ICD groups. Conclusions: Patients with D-ICDs had a nonsignificant trend toward higher mortality and heart failure rates than patients with S-ICDs.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1542-474X.2005.00063.x
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  • 9
    Electronic Resource
    Electronic Resource
    Effect of Alumina Additions on Microstructural Aspects of the β to α Transformation in Tantalum (V) Oxide (2005)
    Oxford, UK : Blackwell Science Inc
    Journal of the American Ceramic Society 88 (2005), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Tantalum (V) oxide (Ta2O5) has potential applications as part of an environmental barrier coating system for Si3N4-based turbine components. However, at elevated temperatures, Ta2O5 undergoes a phase transformation from the orthorhombic (β) phase to the tetragonal phase (α), which is undesirable because of the associated volume change. The purpose of the present work was to study the effect of alumina additions (0–5 wt%) on the β to α transformation temperature, and associated modifications to the Ta2O5 microstructure. Sintered microstructures were characterized using SEM (scanning electron microscopy), and XRD (X-ray diffraction) was used to identify the phases present at room temperature. It was found that for undoped Ta2O5, transformation of the low-temperature β-phase begins at ∼1300°C, and leads to extensive microcracking of the sintered sample. For samples containing alumina, an increase in the transformation temperature was observed. The solubility limit of alumina in Ta2O5 was between 1 and 3 wt%; for samples in which this was exceeded, the AlTaO4 second and phase particles were seen to be highly effective at inhibiting grain growth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1551-2916.2005.00450.x
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  • 10
    Electronic Resource
    Electronic Resource
    Effects of Aluminum and Zirconia Contents on the Sintering of Reaction-Bonded Aluminum Oxide Ceramics (2005)
    Oxford, UK : Blackwell Science Inc
    Journal of the American Ceramic Society 88 (2005), S. 0 
    Details
    ISSN: 1551-2916
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The reaction-bonded aluminum oxide (RBAO) process is an attractive alternative to the conventional processing of Al2O3-based ceramics. The most attractive features of the process are the high strengths, densities, and easy machinability of the green powder compacts, and the low shrinkage and high strengths of the sintered ceramics. These advantages result from the presence of aluminum in the green bodies and are enhanced further with increasing aluminum contents. However, it is apparent that ZrO2-containing RBAO powders with higher aluminum contents (〉45 vol%) are increasingly more difficult to densify, as the start of densification is delayed (shifted to higher temperatures) and the densification rates are decreased. Ultimately, this results in a decrease in the limiting density to which the RBAO ceramic may be sintered. In this study, the cooperative effects of ZrO2 and aluminum contents on the sintering of RBAO ceramics are discussed in terms of densification behavior and microstructural analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1551-2916.2005.00393.x
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