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  • 1
    Electronic Resource
    Electronic Resource
    Rheoforging of Wrought Aluminum Alloys (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 141-143 (July 2008), p. 271-276 
    Details
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Notes: Wrought aluminum alloys have wide variety applications in aerospace and automobileindustries, due to their superior properties compared to casting aluminum alloys. Rheoforging is amodification of thixoforging, which starts directly from the liquid phase instead of reheating of abillet. In the present process, suitable semi-solid slurries of wrought aluminum alloys are prepared bythe LSPSF (low superheat pouring with a shear field) rheocasting process within 25s. The effects ofprocessing conditions on the degree of spherical grain refinement in 2024, 6082 and 7075 alloys arediscussed. 2024 and 7075 alloys have been used in order to investigate rheoformability of highperformance aluminum alloy. Experimental results show that rheoforging based on LSPSF processcan produce relatively homogeneous microstructure throughout the cup-shaped component. However,high solid fraction of semi-solid slurry promotes metal flow and results in solid/liquid segregation.Subsequent optimized heat treatments raise significantly the mechanical properties. Future potentialsand challenges to be solved are discussed
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/24/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.141-143.271.pdf
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  • 2
    Electronic Resource
    Electronic Resource
    Low-Temperature Synthesis and Micro-Morphology Observation of Transparent MgAl〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 Nano-Ceramics (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 336-338 (Apr. 2007), p. 2308-2311 
    Details
    ISSN: 1013-9826
    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: Transparent MgAl2O4 nano-ceramics were prepared by ultrahigh-pressure-sintering method,using improved nano-sized powder synthesized by high-temperature calcination. The synthesis temperatureswere exactly measured by nichrome-NiSi thermocouple passing through the samples. The micromorphologyof the ceramics was observed by means of dynamic force microscopy (DFM), and therelation between transparency and micro-morphology was investigated. The results show that, thesintering temperatures, now calibrated, of transparent nano-ceramics are just 540~700°C, which are muchlower than those of conventional nano-ceramics and transparent ceramics, and the uniformity of grainsizes and orderliness of the grain array are beneficial to the transparency and integrity of the ceramics
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/53/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.336-338.2308.pdf
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  • 3
    Electronic Resource
    Electronic Resource
    Microstructure Evolution and Mechanical Properties of Rheoformed YL112 Aluminum Alloy (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 141-143 (July 2008), p. 163-168 
    Details
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Notes: Rheo-die casting (RDC) based on LSPSF (low superheat pouring with a shear field)rheocasting process has been exploited. In case of secondary die casting aluminum alloy YL112,LSPSF allowed for preparation of sound semi-solid slurry in 15-20s that fully meet the productionrate of HPDC, the primary α-Al exhibiting a mean equivalent diameter of 70 μm and shape factor of0.93, without any entrapped eutectic. Compared to conventional HPDC, RDC improvesmicrostructures in castings. Secondary solidification of semi-solid slurry takes place uniformlythroughout the entire cavity, producing an extremely fine and uniform microstructure. Theexperimental results show the RDC 380 alloy has much improved integrity and mechanicalproperties, particularly elongation, and heat treatment can be used to enhance the mechanicalproperties
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/24/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.141-143.163.pdf
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  • 4
    Electronic Resource
    Electronic Resource
    The Austenite Inverse Phase Transformation Quenching in Zero Time Holding of 20MnV Steel (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 575-578 (Apr. 2008), p. 1177-1183 
    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 effect of second quenching temperature in zero time holding on 20MnV steel'sstrength and hardness was studied by the orthogonal regressive principle. The microstructure andproperty of the steel after austenite inverse phase transformation quenching in zero time holdingwere analyzed. Experiment results showed that the fine lath martensite of 20MnV steel wasobtained through austenite inverse phase transformation quenching in zero time holding at830°C-930°C. Within the range of Experiment's temperature, the structure of this steel quenched at830°C is the finest. The microstructure will become coarse and the strength and hardness willbecome lower if the temperature goes up. The property of this steel can be increased remarkably byaustenite inverse phase transformation quenching in zero time holding at lower temperature
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/18/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.575-578.1177.pdf
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  • 5
    Electronic Resource
    Electronic Resource
    Continuous Fabrication of Sound Semi-Solid Slurry for Rheoforming (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Solid state phenomena Vol. 116-117 (Oct. 2006), p. 425-428 
    Details
    ISSN: 1662-9779
    Source: Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
    Topics: Physics
    Notes: An alternative method has been proposed for the continuous and sample production ofSSM slurry for the rheo-forming process. The process named “Low Superheat Pouring with a ShearField (LSPSF)” dose not use the conventional stirring process, instead, it uses solidificationconditions to control nucleation, nuclei survival and grain growth by means of low superheatpouring, vigorous mixing and rapid cooling during the initial stage of solidification combined withthereafter a much slower cooling. The method has been applied to A356, 201 and A380 Al-alloys.The primary phases present in average equivalent diameter of 40-70μm, 35-50μm and 50-70μm forA356, 201 and A380, respectively. The morphology of primary phases is nearly spherical with shapefactor of 0.78-0.86, 0.71-0.83 and 0.85-0.96 for A356, 201 and A380, respectively. For each of thosealloys, there is no eutectic entrapped within the primary phase. The advantages of the LSPSF includeprocess simplicity with high efficiency, easy incorporation into existing metal forming installationwithout infrastructure changes and a wide process window for pouring temperature
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/22/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.116-117.425.pdf
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  • 6
    Electronic Resource
    Electronic Resource
    Ge/Si nanowire heterostructures as high-performance field-effect transistors (2006)
    [s.l.] : Nature Publishing Group
    Nature 441 (2006), S. 489-493 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Semiconducting carbon nanotubes and nanowires are potential alternatives to planar metal-oxide-semiconductor field-effect transistors (MOSFETs) owing, for example, to their unique electronic structure and reduced carrier scattering caused by one-dimensional quantum confinement effects. Studies ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nature04796
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  • 7
    Electronic Resource
    Electronic Resource
    Single-crystal metallic nanowires and metal/semiconductor nanowire heterostructures (2004)
    [s.l.] : Macmillian Magazines Ltd.
    Nature 430 (2004), S. 61-65 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] Substantial effort has been placed on developing semiconducting carbon nanotubes and nanowires as building blocks for electronic devices—such as field-effect transistors—that could replace conventional silicon transistors in hybrid electronics or lead to stand-alone nanosystems. ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nature02674
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  • 8
    Electronic Resource
    Electronic Resource
    MgAl〈sub〉2〈/sub〉O〈sub〉4〈/sub〉 Transparent Nano-Ceramics Prepared by Sintering under Ultrahigh Pressure (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 280-283 (Feb. 2007), p. 549-552 
    Details
    ISSN: 1013-9826
    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 first experimental work to produce transparent MgAl2O4 nano-ceramics was reported in this paper. The sintering characteristics of transparent nano-ceramics were investigated at relatively low temperature (800 ~ 1100°C) under ultrahigh pressure (2 ~ 5 GPa) using hydrostatic equipment. The morphologiesand phases of ceramics were observed by means of SEM and XRD, respectively. The grain sizes of the ceramics are shown to be less than one hundred nanometers, far smaller than the sizes of common transparent ceramics. Furthermore, the higher the sintering temperature and pressure are, thegreater the extent of densification is. At the same temperature, the higher the pressure is, the smaller the average grain size is. Under the same pressure, the higher the temperature is, the larger the average grain size is. The optimal sintering condition for preparing transparent nano-ceramics was also determined
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/49/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.280-283.549.pdf
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  • 9
    Electronic Resource
    Electronic Resource
    Preparation and Characterization of Transparent Nanocrystalline Ceramics (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 368-372 (Feb. 2008), p. 402-406 
    Details
    ISSN: 1013-9826
    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 transparent nanocrystalline MgAl2O4 spinel ceramics were synthesized at lowtemperatureand high-pressure conditions with low-cost nano-sized MgAl2O4 powder. The sinteringcharacteristics of transparent nano-ceramics were investigated at 500~700oC under 2 ~ 5 GPa. Theoptimal sintering condition for preparing transparent nano-ceramics was determined. The microstructureand phase composition of powder, as well as the microstructures, morphologies, optical properties,densities and mechanical properties of synthetic ceramics were investigated. The grain sizes of thesynthetic ceramics are less than 100 nm, far smaller than those of usual transparent micron-ceramics, andthe average grain size depends on the pressure and temperature. The transmittance at the saturationplateau can near 80%. The relative densities of all samples are less than 99%, however, they are highlytransparent. The toughness, derived from energy dissipation, of the transparent nano-ceramics wasinvestigated and was compared with that of transparent micron-ceramic
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/56/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.368-372.402.pdf
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  • 10
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    Hemispheric Asymmetry of Functional Brain Networks under Different Emotions Using EEG Data (2020)
    Molecular Diversity Preservation International
    Details
    Publication Date: 2020-08-26
    Description: Despite many studies reporting hemispheric asymmetry in the representation and processing of emotions, the essence of the asymmetry remains controversial. Brain network analysis based on electroencephalography (EEG) is a useful biological method to study brain function. Here, EEG data were recorded while participants watched different emotional videos. According to the videos’ emotional categories, the data were divided into four categories: high arousal high valence (HAHV), low arousal high valence (LAHV), low arousal low valence (LALV) and high arousal low valence (HALV). The phase lag index as a connectivity index was calculated in theta (4–7 Hz), alpha (8–13 Hz), beta (14–30 Hz) and gamma (31–45 Hz) bands. Hemispheric networks were constructed for each trial, and graph theory was applied to quantify the hemispheric networks’ topological properties. Statistical analyses showed significant topological differences in the gamma band. The left hemispheric network showed significantly higher clustering coefficient (Cp), global efficiency (Eg) and local efficiency (Eloc) and lower characteristic path length (Lp) under HAHV emotion. The right hemispheric network showed significantly higher Cp and Eloc and lower Lp under HALV emotion. The results showed that the left hemisphere was dominant for HAHV emotion, while the right hemisphere was dominant for HALV emotion. The research revealed the relationship between emotion and hemispheric asymmetry from the perspective of brain networks.
    Electronic ISSN: 1099-4300
    Topics: Chemistry and Pharmacology , Physics
    Published by Molecular Diversity Preservation International
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