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  • 1
    Electronic Resource
    Electronic Resource
    Superplastic Deformation of Nano-Sized α-Sialon Ceramics (2007)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 336-338 (Apr. 2007), p. 1001-1004 
    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: In previous report, we succeeded in preparing dense nano-sized ceramics with the compositionof Y- α-sialon (m=1.35, n=0.675) by high-energy mechanical milling followed by spark plasma sintering.The superplastic deformation of the obtained nano-ceramics was studied in this report. A good ductility ofthe nano-sized ceramics has been confirmed, which arised from the nano-sized grains and large amount oftransient liquid phase. The effects of deformation on the phase and microstructural evolution were alsostudied. The nano-sized grains promoted the formation of elongated α-sialon grains during post-annealingat 1850oC for 3 h, which would strengthen and toughen the deformed 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.336-338.1001.pdf
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  • 2
    Electronic Resource
    Electronic Resource
    Positron Annihilation on the Surfaces of Single Crystals of Si, SiO〈sub〉2〈/sub〉, Graphite and Cu (2008)
    s.l. ; Stafa-Zurich, Switzerland
    Materials science forum Vol. 607 (Nov. 2008), p. 152-154 
    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: Slow positron beam technique has been applied to measure the Doppler broadening spectra for single crystals of Cu, SiO2, graphite, virgin Si, and Si without oxide film. The results show that the Cu ratio curve shows a high peak due to Cu having 10 electrons in the 3d shells. The ratio curve of SiO2 is higher than that of graphite. For the single crystal of Cu, SiO2, graphite, and Si without oxide film, the S (W) parameters decrease (increase) as positron implantation energy increasing. Defects on the surface lead to higher S (lower W) value. For the virgin Si and the thermally grown SiO2-Si samples, the S (W) parameters increase (decrease) as positron implantation energy increasing. It can be due to Si atom at surface, with two dangling bonds, tend to form silicon oxide with O. The W parameter for the single crystal of Cu is relatively high as compared with that of the single crystals of SiO2 and graphite
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/02/20/transtech_doi~10.4028%252Fwww.scientific.net%252FMSF.607.152.pdf
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  • 3
    Electronic Resource
    Electronic Resource
    Fabrication of α-Sialon Nano-Ceramics (2006)
    s.l. ; Stafa-Zurich, Switzerland
    Key engineering materials Vol. 317-318 (Aug. 2006), p. 629-632 
    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: Y- α-sialon (m=1.35, n=0.675) ceramics were prepared by high-energy mechanicalmilling followed by spark plasma sintering. The milling promoted not only liquid-phase sintering,but also phase transformation from β-Si3N4 to α-sialon. Under the same holding time of 5 min,milled powder could be completely densified at 1500oC, which is about 250oC lower than thatrequired for as-received powder. The temperature where the phase transformation finished was1600oC and 1750oC for milled and as-received powder, respectively. The grain size of obtaineddense ceramics from milled powder was significantly decreased. Nano-sized dense ceramics havebeen obtained by sintering the milled powder at 1500oC for 5 min. Although 100 % α-sialon has notbeen achieved, the nano-sized ceramics can be used for superplastic deformation, taking advantageof small grain size and large amount of transient liquid phase
    Type of Medium: Electronic Resource
    URL: http://www.tib-hannover.de/fulltexts/2011/0528/01/51/transtech_doi~10.4028%252Fwww.scientific.net%252FKEM.317-318.629.pdf
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  • 4
    Electronic Resource
    Electronic Resource
    Studies on carbon/sulfur cluster anions produced by laser vaporization: Experiment (collision-induced dissociation) and theory (ab initio calculation). I. C2Sm− (1≤m≤11) (2000)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 112 (2000), S. 9310-9318 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Binary cluster anions composed of carbon and sulfur atoms have been produced from laser vaporization of a sample mixed with sulfur and carbon powders in a 20:1 ratio. They were mass-selected and their molecular formula was determined by collision-induced dissociation. The clusters consist of even carbon atoms only and their number of clustering sulfur atoms equals or exceeds that of carbon atoms. Ab initio calculations at the ROHF/6-31G* level have been performed for the cluster anions containing two carbon atoms, C2Sm− (1≤m≤10). Geometries of various isomeric structures of the clusters were optimized and their energies were compared to find the most stable isomers. For the singly charged anions, attachment of an additional electron leads to break their sulfur rings, and the isomers with two dangling sulfur atoms and a closed ring have the lowest energy. According to the experimental and theoretical investigations, the two carbon atoms form the bone of the clusters, and ejection of two sulfur atoms is the most competitive dissociation pathway of the cluster anions. © 2000 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.481552
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  • 5
    Electronic Resource
    Electronic Resource
    Salmonella typhimurium enterotoxin epitopes shared among bacteria (1994)
    Oxford, UK : Blackwell Publishing Ltd
    FEMS microbiology letters 118 (1994), S. 0 
    Details
    ISSN: 1574-6968
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Abstract The deduced amino acid sequence of the cloned Salmonella enterotoxin gene (stn) was used to prepare anti-peptide antibodies. These antibodies were then employed to screen isolates of this enteric pathogen for the synthesis of protein enterotoxin (Stn). Cell lysates of all Salmonella isolates tested displayed a prominent immunoblot band of approximately 29 kDa, which was consistent with the size of the cloned stn gene product. Among other Gram-negative bacteria examined, isolates of KlebsiellaEnterobacter, and Citrobacter exhibited a similar-sized protein that reacted strongly with the Stn antibodies. Since the stn gene was located opposite the hydrogenase regulatory genes (hydHG) required for hydrogen metabolism in bacteria, our data suggested that only in Salmonella and some other members of the family Enterobacteriaceae had the DNA sequence evolved, presumably through point mutations, into an expressed gene product of similar size.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1574-6968.1994.tb06834.x
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  • 6
    Electronic Resource
    Electronic Resource
    α-SiAlON Ceramics Obtained by Slip Casting and Pressureless Sintering (2003)
    Westerville, Ohio : American Ceramics Society
    Journal of the American Ceramic Society 86 (2003), 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: Dense α-SiAlON ceramics were obtained by pressureless sintering of green compacts prepared using slip casting. The rheological properties of the reaction SiAlON suspension were optimized to achieve a high degree of dispersion with a high solids volume fraction, which resulted in homogeneous and relatively dense green bodies with high sintering ability, which could be densified by pressureless sintering at 1750°C for 2 h. The sintered samples revealed a high degree of uniformity and almost fully dense microstructures that consisted of many small, elongated grains homogeneously dispersed in the fracture surfaces, which had properties comparable with those of other SiAlONs obtained using hot pressing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1151-2916.2003.tb00027.x
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  • 7
    Electronic Resource
    Electronic Resource
    The dynamics of political and economic interactions between Mainland China and Taiwan (2003)
    Oxford, UK : Blackwell Publishing Ltd
    Papers in regional science 82 (2003), S. 0 
    Details
    ISSN: 1435-5957
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Geography , Economics
    Notes: Abstract. The purpose of this article is to examine the trade and economic linkages across the Taiwan straits from the dynamic economic and political perspectives. In particular, we study the pattern and structure of the cross-straits trade and business linkages using game theory arguments. We assess the increasing economic interdependence between Taiwan and Mainland China, particularly the enduring political deadlock, by examining issues related to “Taiwanification”, the dynamic instability, Taiwan's Mainland policy, and Taiwan in Beijing's Grand Strategy.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s10110-003-0164-0
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  • 8
    Electronic Resource
    Electronic Resource
    Simulation and design of a superconducting eddy current probe for nondestructive testing (1998)
    [S.l.] : American Institute of Physics (AIP)
    Review of Scientific Instruments 69 (1998), S. 499-506 
    Details
    ISSN: 1089-7623
    Source: AIP Digital Archive
    Topics: Physics , Electrical Engineering, Measurement and Control Technology
    Notes: Numerical modeling studies were carried out for the design and performance evaluation of an eddy current probe for superconducting quantum interference device (SQUID) based noncontacting electromagnetic nondestructive testing. The probe utilizes high-Tc SQUID from electromagnetic interference and to focus magnetic flux due to the eddy current excitation coil into the object under test (OUT). This is very important in order to achieve "self-nulling," where the probe responds only to the defects in the OUT. Simulations are carried out with the eddy current probe located a finite distance above a defect free conducting half-space of infinite thickness. Eddy current densities in the OUT are then calculated for various probe designs. These eddy current densities give an indication of the flux focusing, and hence increased spatial resolution for combinations of HTS and μ-metal shielding. Shielding factors are also calculated for the screening of the primary excitation field and the "defect-free" eddy current field. Agreement with the analytical solution of a simple solenoid above a conducting half-space verifies the numerical method.© 1998 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1148722
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  • 9
    Electronic Resource
    Electronic Resource
    New Strategies for Preparing NanoSized Silicon Nitride 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: We report the preparation of nanosized silicon nitride (Si3N4) ceramics via high-energy mechanical milling and subsequent spark plasma sintering. A starting powder mixture consisting of ultrafine β-Si3N4 and sintering additives of 5-mol% Y2O3 and 2-mol% Al2O3 was prepared by high-energy mechanical milling. After milling, the powder mixture was mostly transformed into a non-equilibrium amorphous phase containing a large quantity of well-dispersed nanocrystalline β-Si3N4 particles. This powder precursor was then consolidated by spark plasma sintering at a temperature as low as 1600°C for 5 min at a heating rate of 300°C/min. The fully densified sample consisted of homogeneous nano-Si3N4 grains with an average diameter of about 70 nm, which led to noticeable high-temperature ductility and elevated hardness.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1551-2916.2005.00187.x
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  • 10
    Electronic Resource
    Electronic Resource
    Temperature-Induced Gelation of Concentrated Sialon Suspensions (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: A temperature-induced gelation method has been developed for the preparation of sialon green bodies composed of Si3N4, AlN, Y2O3, and Al2O3. Using a polyester/polyamine condensation polymer as dispersant, stable suspension containing sialon, precursor powders could be prepared in methyl ethyl keton (MEK)/ethanol (E) solvent mixture with solids loading as high as 60 vol%. The solvency of the dispersant in MEK/E decreased dramatically on cooling. The sedimentation tests showed that the settling behavior changed from slow accumulation at ∼20°C to fast deposition of clusters at −15°C, because of the collapse of dispersant chains adsorbed at the surface of the particles. Steady shear viscosity and oscillatory measurements performed for 60 vol% suspensions as functions of temperature and added amounts of dispersant proved that suspensions were of low viscosity and high stability at room temperature, becoming predominantly very highly viscous and elastic as temperature decreased. The gelation mechanism was mainly based on the coiling up of dissolved dispersant molecules, inducing in situ gelation and the formation of a rigid network bridging the suspended particles. The green bodies showed negligible shrinkage during gelation, a small shrinkage during drying, homogeneous microstructures, narrow pore size distributions, and high relative density. It was possible to achieve dense α-sialon ceramics through pressureless sintering at 1750°C for 2 h.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1551-2916.2005.00160.x
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