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  • Springer  (2)
  • Springer Nature  (1)
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  • 1
    ISSN: 1573-482X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Using the technique of molecular beam epitaxy, an indium passivation layer as thin as several tens of Å was implemented to protect underlying III-V epilayers from carbon and oxygen contamination. After the subsequent desorption of the passivation layer, GaAs-based pseudomorphic high electron mobility transistors (PHEMTs) were regrown. Negligible residual carriers were detected at the interface between the regrown PHEMTs and the underlying layer, resulting in a superior performance. The regrown PHEMTs with a 1 × 100 μm2 gate demonstrated an extrinsic transconductance g me as high as 330 mS mm-1. Microwave measurements showed that the current gain cut-off frequency f t was 26.5 GHz and the maximum oscillation frequency f max was up to 48 GHz. A small-signal equivalent circuit model of the regrown PHEMTs was also evaluated. © 2000 Kluwer Academic Publishers
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of materials science 34 (1999), S. 5899-5906 
    ISSN: 1573-4803
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The interface of Ti-6Al-4V casting and ZrO2 mold with silica binder was investigated by using electron probe microanalyses (EPMA), X-ray diffraction (XRD), and analytical transmission electron microscope (TEM). The interfacial reactions were proceeded by the penetration of liquid titanium through open pores near the mold surface. The metal side consisted of an α-phase layer on the top of the typical α + β two-phase substrate. In the ceramic side, zirconia was reduced by titanium to form oxygen-deficient zirconia ZrO2−x and evolved a gaseous phase (presumably oxygen). The SiO2 binder, dissolved in the ZrO2 mold, could react with titanium to form Ti5Si3 in the metal side. Meanwhile, titanium could transform to titanium suboxides TiyO (y ≥ 2) and the lower phase boundary of cubic ZrO2−x was shifted to ZrO1.76. Some amount of the stabilizer CaO, dissolved in Ti along with ZrO2, could react with Ti(O) to form Ca3Ti2O7 and CaAl4O7 in the reaction zone.
    Type of Medium: Electronic Resource
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  • 3
    Publication Date: 2014-09-11
    Description: The planarian is widely used as a model for studying tissue regeneration. In this study, we used optical coherence tomography (OCT) for the real-time, high-resolution imaging of planarian tissue regeneration. Five planaria were sliced transversely to produce 5 head and 5 tail fragments. During a 2-week regeneration period, OCT images of the planaria were acquired to analyze the signal attenuation rates, intensity ratios, and image texture features (including contrast, correlation, homogeneity, energy, and entropy) to compare the primitive and regenerated tissues. In the head and tail fragments, the signal attenuation rates of the regenerated fragments decreased from −0.2 dB/μm to −0.05 dB/μm, between Day 1 and Day 6, and then increased to −0.2 dB/μm on Day 14. The intensity ratios decreased to approximately 0.8 on Day 6, and increased to between 0.8 and 0.9 on Day 14. The texture parameters of contrast, correlation, and homogeneity exhibited trends similar to the signal attenuation rates and intensity ratios during the planarian regeneration. The proposed OCT parameters might provide biological information regarding cell apoptosis and the formation of a mass of new cells during planarian regeneration. Therefore, OCT imaging is a potentially effective method for planarian studies. Scientific Reports 4 doi: 10.1038/srep06316
    Electronic ISSN: 2045-2322
    Topics: Natural Sciences in General
    Published by Springer Nature
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