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The NiCr/YSZ coating was fabricated on γ-TiAl alloy by double glow plasma surface metallurgy technology and multi-arc ion plating technology. The microstructure, microhardness, bonding strength, and burn resistance of NiCr/YSZ coating were studied in detail. The results showed that the NiCr/YSZ coating was dense and homogeneous, including a duplex structure of top YSZ ceramic coating and underlying Ni-Cr bond coating. The average microhardness of NiCr/YSZ coating was raised by a factor of about 2 compared to the γ-TiAl substrate. The thermal shock test indicated that the composite structure had superior bonding strength and the defects such as metal droplets on the ceramic coating were the source of cracks. The high-energy laser beam destroyed the surface of γ-TiAl alloy, forming protruding combustion products in ablation zone and splashing residues around ablation zone. When coated by NiCr/YSZ coating, the combustion process was delayed through isolating and dissipating heat. The ablation range was controlled and the ablation damage was reduced at the same irradiation power. The NiCr/YSZ coating preliminarily realized to improve the burn resistance of γ- TiAl alloy.

To improve the wear resistance of γ-TiAl alloy, Ta alloy layer was prepared on surface by double glow plasma surface alloying technique. The tribology behavior of Ta alloy layer against Si3N4 at 25℃, 350℃ and 500℃ were comparatively studied. The results showed that Ta alloy layer comprised a deposition layer and a diffusion layer. The deposition layer played a role in protection as a soft film. With the increase of temperature, the wear mechanism of γ-TiAl changed from abrasive wear to coexistence of abrasive wear and oxidation wear. Ta alloy layer’s wear mechanism changed from adhesive wear to coexistence of adhesive wear and oxidation wear. Surface Ta alloying process significantly reduced the wear volume, the specific wear rate and the friction coefficient of γ-TiAl and improved the wear resistance properties of γ-TiAl.

C36H30Cl4O2P2Ti, triclinic, P1̅ (no. 2), a = 9.492(1) Å, b = 9.640(1) Å, c = 10.429(1) Å, α = 102.100(2)°, β = 108.657(2)°, γ = 92.652(2)°, V = 877.4 Å3, Z = 1, Rgt(F) = 0.043, wRref(F2) = 0.106, T = 273 K.

The ultrathin body (UTB) silicon-on-insulator metal-oxide-semiconductor field-effect transistor (MOSFET) is promising for sub-50-nm complementary metal-oxide semiconductor technologies. To explore a high-mobility channel for this technology, this paper presents an examination of Si and Ge hole sub-band structure in UTB MOSFETs under different surface orientations. The dependence of the hole subband structure on the film thickness (TBody) was also studied in this work. We found that the valence-band mixing in the vicinity of the zone center Γ is strongly dependent on TBody for both Si and Ge, particularly for the <110> surface orientation. This gives rise to the following two phenomena that crucially affect the electrical characteristics of p-MOSFETs: (1) an anomalous increase of quantization mass for <110> Si and Ge surfaces as TBody is scaled below 5 nm. (2) The dependence of energy dispersion and anisotropy on TBody especially for the <110> surface, which advantageously increases hole velocity along the [011] channel as TBody is decreased. The density of states for different surface orientations are also calculated, and show that—for any given surface orientation—Ge has a smaller density of states than Si. The Ge <110> surface has the lowest density of states among the surface orientations considered. [ABSTRACT FROM AUTHOR]

In the paper a combined experimental and theoretical investigation of the longitudinal optical phonon sidebands (PSBs) in the luminescence of free excitons in GaN at moderately high temperatures was reported. The spectral features, including line broadening, shift, and asymmetry of the one- and two-phonon PSBs, were revealed both experimentally and theoretically. It is found that the linewidth of the one-phonon PSB is surprisingly always larger than that of the two-phonon PSB in the interested temperature range. Moreover, the thermal broadening rates of the one- and two-phonon PSBs are considerably different. We adopted the Segall–Mahan theory [B. Segall and G. D. Mahan, Phys. Rev. 171, 935 (1968)] to compute the PSB spectra of the free excitons in GaN. Only one adjustable parameter, the effective mass of the holes, was used in the calculations. For the one-phonon PSB, an excellent agreement between theory and experiment is achieved when an adequate effective mass of the holes was used. [ABSTRACT FROM AUTHOR]

Thin films of HfO[sub 2] high-k dielectric have been prepared by pulsed-laser deposition at various substrate temperatures and pressures. X-ray diffraction, atomic force microscopy, secondary ion mass spectroscopy and ellipsometry were used to characterize the deposited films. Experimental results show that substrate temperature has little effect on the stoichiometry, while deposition pressure plays an important role in determining the ratio of Hf and O. It is also found that the optical properties of the HfO[sub 2] thin films have strong dependence on both the deposition temperature and pressure. The electrical properties of HfO[sub 2] metal-insulator-metal (MIM) capacitors were investigated at various deposition temperatures. It is shown that the HfO[sub 2] (56 nm) MIM capacitor fabricated at 200 °C shows an overall high performance, such as a high capacitance density of ∼3.0 fF//µm², a low leakage current of 2×10[sup -9]A/cm² at 3 V, low-voltage coefficients of capacitance, and good-frequency dispersion properties. All of these indicate that the HfO[sub 2] MIM capacitors are very suitable for use in Si analog circuit applications. [ABSTRACT FROM AUTHOR]

We present a physical model to calculate the direct tunneling hole current through ultrathin gate oxides from the inversion layer of metal–oxide–semiconductor field-effect transistors. A parametric self-consistency method utilizing the triangular well approximation is used for the electrostatics of the inversion layer. For hole quantization in the inversion layer, an improved one-band effective mass approximation, which is a good approximation to the rigorous six-band effective mass theory, is used to account for the band-mixing effect. The tunneling probability is calculated by a modified Wentzel–Kramers–Brilliouin (WKB) approximation, which takes the reflections near the Si/SiO[sub 2] interfaces into account. It is found that the parabolic dispersion in the SiO[sub 2] band gap used in the WKB approximation is only applicable for hole tunneling in oxides thinner than about 2 nm and for low gate voltage. A more reasonable Freeman–Dahlke hole dispersion form with significantly improved fitting to all experimental data for different oxide thickness and gate voltage range is adopted and discussed. © 2002 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Automatically recognizing and tracking dynamic targets on the sea is an important task for intelligent navigation, which is the prerequisite and foundation of the realization of autonomous ships. Nowadays, the radar is a typical perception system which is used to detect targets, but the radar echo cannot depict the target's shape and appearance, which affects the decision-making ability of the ship collision avoidance. Therefore, visual perception system based on camera video is very useful for further supporting the autonomous ship navigational system. However, ship's recognition and tracking has been a challenge task in the navigational application field due to the long distance detection and the ship itself motion. An effective and stable approach is required to resolve this problem. In this paper, a novel ship recognition and tracking system is proposed by using the deep learning framework. In this framework, the deep residual network and crosslayer jump connection policy are employed to extract the advanced ship features which help enhance the classification accuracy, thus improves the performance of the object recognition. Experimentally, the superiority of the proposed ship recognition and tracking system was confirmed by comparing it with state of-the-art algorithms on a large number of ship video datasets. [ABSTRACT FROM AUTHOR]