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In this study, surface Cr-Nb alloying was realized on γ-TiAl using double glow plasma hollow cathode discharge technique. An inter-diffusion layer was generated under the surface, composed of Cr2Nb intermetallic compounds. After Cr-Nb alloying, the surface nanohardness of γ-TiAl increased from 5.65 to 11.61 GPa. The surface H/E and H3/E2 increased from 3.37 to 5.98 and from 0.64 to 4.15, respectively. Cr-Nb alloying and its effect on fretting wear were investigated. The surface treatment resulted in improved plastic deformation and fretting wear resistance of γ-TiAl. The fretting wear test showed that an average friction coefficient of γ-TiAl against Si3N4 ball was significantly decreased after Cr-Nb alloying. The fluctuation of friction coefficient during running-in stage was significantly improved. The friction behavior of both γ-TiAl before and after Cr-Nb alloying could be divided into distinctive stages including formation of debris, flaking, formation of crack, and delamination. It was observed that the high hardness, resistance to plastic deformation, and fatigue resistance of γ-TiAl after Cr-Nb alloying could inhibit the formation of debris and delamination during friction test. The fretting wear scar area and the maximum wear scar depth were decreased, indicating that the wear resistance of γ-TiAl has been greatly improved after Cr-Nb alloying. The results indicated that plasma surface Cr-Nb alloying is an effective way for improving the fretting wear resistance of γ-TiAl in aviation area.

Hard ceramic and ductile metal materials combined in multilayered structures provide superior wear and oxidation resistance to the single layer, which has been applied extensively to components subjected to high-temperature oxidation and wear. In this paper, the oxidation and wear properties of Cr/CrC multilayer coating obtained on γ-TiAl alloy by an emerging technology, that is double glow plasma surface alloying technology, were reported. Sliding wear and oxidation tests were performed on Cr/CrC multilayer as well as on chromising reference coating. The friction coefficients of Cr/CrC multilayer at room and high temperature were 0.2 and 0.175 respectively, about only 22.2% and 35% of the γ-TiAl substrate. The Cr/CrC multilayer oxidized approximately parabolically, with lower oxidation rate than the chromising coating. The oxidation mechanism of the Cr/CrC multilayer was mainly dominated by carbide oxidation and dense Cr2O3 scale oxide development.

The influences of intense terahertz laser and magnetic fields on shallow-donor states in GaAs bulk semiconductors in the Faraday geometry are studied theoretically in the framework of the effective-mass approximation. The interaction between the laser field and the semiconductor is treated nonperturbatively by solving analytically the time-dependent Schrodinger equation in which the two external fields are included exactly. In the nonresonant region, we have found that the binding and transition energies decrease with increasing laser-field intensity or decreasing laser-field frequency, and the binding energy increases with magnetic field. For relatively low radiation levels, the transition energy first slowly decreases with increasing magnetic field, but after a critical value, it rapidly increases with increasing magnetic field. However, it slowly decreases with magnetic field when the laser-field intensity is strong enough. Furthermore, in the vicinity of the resonant regime, the oscillatory behaviours of the binding and transition energies with laser-field frequency and magnetic field are observed. These results obtained indicate the possibility of manipulating the shallow impurity states in semiconductor by changing the intense laser-field frequency and intensity and the magnetic field, which gives a new degree of freedom in semiconductor device application.

A Cr–Mo alloyed layer was prepared on a TiAl-based alloy using plasma surface alloying technique. The isothermal oxidation kinetics of the untreated and treated samples was examined at 850 °C. The microstructure and phase composition of the alloyed layer were analyzed by scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and X-ray powder diffraction (XRD). The morphology and constituent of the oxide scales were also analyzed. The results indicated that the oxidation resistance of TiAl was improved significantly after the alloying treatment. The oxide scale eventually became a mixture of Al2O3, Cr2O3 and TiO2. The oxide scale was dense and integrated throughout the oxidation process. The improvement was mainly owing to the enhancing of scale adhesion and the preferential oxidation of aluminum brought by the alloying effect for TiAl-based alloy.

Al slurry coatings, an alternative of Cd coating to protect against corrosion in the aerospace industry, are currently being explored to satisfy the stringent technology and safety requirements for aeronautical applications. The results of salt fog corrosion exposure, fluid corrosion exposure (immersion), humidity resistance, electrical conductivity, galvanic corrosion, embrittlement, and fatigue indicate that Al slurry coatings can be used as an alternative of Cd coatings. However, the tribological property of Al slurry coatings has still not been investigated. Two types of aluminum slurry coatings on 300M steel were produced using the innovative technological process and characterized by scanning electron microscope, nanoindentation tests, and adhesion tests. The H/E and H 3/E 2 ratios of the two-layer Al slurry-coated sample were almost four times higher than the Cd-Ti plating-coated sample. The dry wear test results show that the friction coefficient of the two-layer Al slurry coating independently from the load was lower than the Cd-Ti plating. The width of the wear track of the two-layer Al slurry coating was significantly narrower, only 62% of the Cd-Ti plating wear scar. Compared to the Cd-Ti plating, an excellent wear resistance of the two-layer Al slurry coating can be attributed to its high resistance to plastic deformation and good load-bearing capacity. The results indicate that the two-layer Al slurry coating is an excellent alternative to Cd coatings in the aerospace industry.

Double-glow plasma coatings are recommended for metallic components to mitigate the damage induced by complex loading conditions. In this paper, Cr–Nb alloyed layer was formed onto the TiAl substrate via a double-glow plasma process to enhance its anti-fretting wear performance. Nano-indentation and scratch tests were used to evaluate the mechanical properties of the coating. The fretting wear behaviour of the coating was investigated using a pin-on-plate fretting rig by rubbing against the Si3N4 ball. The 7 µm thick Cr–Nb coating was well bonded to the substrate with the 2 µm thick diffusion layer. The hardness of the coating was 9.5 GPa, which was 1.6 times greater than that of the uncoated TiAl substrate. Scratch tests showed that the critical load of Cr–Nb coating was 17.6 N. The fretting wear mechanism of the coatings was discussed in detail in this paper.

Double-glow plasma (DGP) coatings are recommended for metallic components to mitigate the damage induced by complex working conditions in previous studies. In this paper, Nb-rich (Cr–Nb4) a...

We demonstrate theoretically that exchange interaction induced by electron-hole scattering via Coulomb interaction can cause a hybridized gap in InAs/GaSb based type II and broken-gap quantum wells. The hybridized energy spectra are obtained analytically at the low temperature and long wave limits. An electric field depended hybridized gap about 4 meV opens at the anti-crossing points of the hybridized energy spectra, in accordance with experimental measurements. The hybridized gap varies linearly with the gate electric voltage due to the fact that the electric field can change the exchange self-energy by tuning the overlap of the wavefunctions and the Fermi energy. Our theoretical results can give a deep insight of the origin of the hybridized gap and provide a simple way to determine the value and the position of the hybridized gap in the presence of the gate electric voltage.

The Ta coating with corrosion resistance is grown on the γ-TiAl substrate by double-glow plasma surface metallurgy technique, followed by the electrochemical test in 10 wt%, 20 wt% HCl and 10 wt%, 40 wt% H2SO4 solution. The data of nanohardness and elastic modulus are collected by the nanoindention test. The adhesion strength of Ta coating is investigated by means of the scratch test. The study of corrosion resistance is performed using potentiodynamic polarization and electrochemical impedance spectroscopy and measured by SEM and X-ray diffraction. Results highlight that the Ta coating is tightly bonded to the γ-TiAl substrate, consisting of the deposition layer and diffusion layer. Experimental data indicate that the Ta coating presents excellent corrosion resistance, which is confirmed by the high values of polarization resistance (Rp) and the low values of corrosion current density (icorr). The surface nanohardness of the Ta coating is improved from 3.41 to 7.29 GPa, nearly twice of that of the substrate. The Ta2O5 formed on the coating is able to hold back the penetration of adverse ions inwardly, owing to its dense structure and adhesion effect. Copyright © 2017 John Wiley & Sons, Ltd.

A Zr–Y alloyed layer was prepared onto the surface of γ-TiAl using double-glow plasma surface alloying technique (DG technique). The results showed that the Zr–Y alloyed layer was comprised of deposited sub-layer and diffused sub-layer, with a total layer thickness of about 20 μm. The nano-indentation test result showed that the nano-hardness of Zr–Y alloyed layer was 2.35 times that of γ-TiAl. The scratch test was carried to evaluate the adhesion strength of Zr–Y alloyed layer. The tribological behaviours were investigated both at ambient temperature and 500°C. Under dry sliding condition, the friction coefficient of the Zr–Y alloyed layer was lower than that of the γ-TiAl. The specific wear rate of γ-TiAl in the presence of Zr–Y alloyed layer was approximately one fifth that in the absence of the alloyed layer. The excellent wear resistance of Zr–Y alloyed layer could be attributed to the high hardness or load-carrying ability.

To improve the oxidation resistance of Ti6Al4V alloy, it was coated with a Cr–Ni alloy with 20, 40, 60, and 80 at.% Ni content using the double-glow plasma surface metallurgy technology. The coatings were dense, uniform, and compact, including a complete structure of deposited layer, interdiffusion layer, and sputtering-affected zone. The effect of Ni content on the isothermal oxidation behavior of coating was investigated at 750, 850, and 950 °C. The results show that the oxide scale consisted of NiO and Cr 2 O 3 . The morphology and distribution of NiO in oxide scale were affected by oxidation temperature and Ni content. When the Ni content was ≤40 at.%, the oxidation resistance of the Cr–Ni alloy coating was enhanced.

Based on the solution to the rate equations of interactions between laser and sodium atoms, the excitation probability of sodium atoms is achieved. The return photons at 330 nm are numerically calculated for the 1 W laser power at the sodium layer in the mesosphere. Results show that a long pulse laser with a few microsecond durations and 1000 Hz repetition rates can well excite the polychromatic laser guide star to obtain no less return photons at 330 nm than that by the continuous-wave laser in a given condition. In order to obtain enough return photons to satisfy the requirement of tip-tilt detection, the parameters of linewidth, durations, repetition rates, polarization and launch diameters of the laser should be properly chosen. And effects of the laser launch diameters and the atmospheric turbulence on the return photons are slight. For the wonderful vertical atmospheric transmittance T0=0.5 at the Starfire Optical Range, Mauna Kea and Paranal, considering the effects of geomagnetic field, when the power of launch laser varies from 10 W to 25 W with the zenith angles from 0° to 40°, the return photons at 330 nm reach 104 ph/m2/s.

We have presented a theoretical study on shallow-donor-related photoionization cross section (PICS) in semiconductors subjected to hydrostatic pressure, magnetic field, and intense laser field within the Vogit configuration. Calculations are performed for the donor ground state using a combination of nonperturbative and variational methods in which intense laser field is exactly taken into account via a laser-dressed Coulomb potential (LdCP). We find that the overall shape of shallow-donor-related PICS depends upon the incident optical field polarization, which is more significant when the incident optical field polarization is parallel to the magnetic field. The donor ground-state binding energy and the optical integrals act in an opposite manner to tailor the magnitudes and peak positions of shallow-donor-related PICS by changing radiation field through the LdCP or by changing magnetic field, hydrostatic pressure, and temperature, leading to a blueshift or redshift of shallow-donor-related PICS spectrum and to a decrease or increase of shallow-donor-related PICS magnitude manipulated by these factors. Thus, we can control the properties of shallow-donor-related PICS with an appropriate choice of two external applied fields, hydrostatic pressure, and temperature to meet some special needs in designing and developing new efficient optoelectronic devices.

Ti–CrNi alloy coatings with 20, 40, 60 and 80 at-%Ni were prepared on Ti6Al4V alloy surface by double glow plasma surface alloying technique. The cyclic oxidation behaviour of the coatings was investigated at 750, 850 and 950°C. The results show that each coating has a complete structure of settled layer, mutual diffusion layer and sputtering affected zone. When the Ni content was 40 at-%, the Ti–CrNi alloy coating showed the best cyclic oxidation resistance. The oxide scale with ‘Cr2O3 film+NiO film’ structure showed the best resistance to peeling.

Surface chromizing of Ti6Al4V alloys was achieved by double glow plasma surface metallurgy technology. Effects of working time, substrate–target distance, argon pressure and surface temperature of substrate on chromium coating were investigated in detail. The results show that the structure of coating achieved by double glow plasma surface chromizing includes a complete structure of surface deposited layer, inter diffusion layer and sputtering-affected zone. Working time has a significant effect on the composition, morphology and structure of plasma chromium coating. An increasing number of β-Ti turned into α-Ti and TiCr 2 phases precipitated in the inter diffusion layer with rising of surface temperature of Ti6Al4V and working time. Argon pressure and the substrate–target distance mainly affected the surface deposited layer of coating. A multilayered deposited structure appeared in the coating when working time was 5 h, which led to the degradation of coating.

In this paper, Zr and Zr–Er alloyed layers were deposited onto the TC11 alloy by using double-glow plasma surface alloying technique. Microstructure analysis showed that Zr and Zr–Er alloyed layers were both well bonded to the substrate without defects of porosity and cracks. Nanoindentation test reflected that Zr and Zr–Er alloyed layers not only possessed high hardness but also had good elastic property. The electrochemical behavior of Zr and Zr–Er alloyed layers was comparatively investigated by using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) in a 10 wt.% HCl solution. The results presented that the changing trend of the sample's corrosion resistance increased in the following sequence: TC11 substrate

In the present study, a dense W-Mo coating was formed onto the gear steel by using double-glow plasma surface alloying technique. The nanoindentation test was used to measure the hardness and elasticity modulus of the coating. The scratch test was applied to evaluate the critical load for coating delamination, which measured the adhesion strength of the coating. The tribological behavior of the W-Mo coating was estimated using a pin-on-disc tribometer by rubbing against the Si 3 N 4 ceramic ball. Results showed that the W-Mo coating was well diffusely bonded to the substrate. In terms of the H/E and H 3 /E 2 ratios, the coated sample was nearly two times greater than that of the uncoated sample. The specific wear rates of the W-Mo coating at room and high temperature were 8.1 × 10 − 5 mm 3 N − 1 m − 1 and 11.2 × 10 − 5 mm 3 N − 1 m − 1 respectively, about only 19% of that of the uncoated sample. The excellent wear resistance of the W-Mo coating may be due to its high resistance to plastic deformation and good load bearing capacity.

We present a theoretical study of the nonlinear optical properties of shallow-donor impurities in semiconductors subjected to magnetic fields, hydrostatic pressures, and intense laser illumination within the Voigt configuration. The donor energy levels and their wave functions are obtained using a combination of nonperturbative and variational methods where intense laser field effects are exactly taken into account through a laser-dressed Coulomb potential (LdCP). The combined effects of radiation and magnetic fields, hydrostatic pressures, and temperatures on the linear, third-order nonlinear, and total optical absorption coefficients (OACs) for the 1 s → 2 p ± and 2 p z transitions are investigated using a compact density-matrix approach. We find that the transition energies and geometric factors can be increased or decreased by changing external fields via the LdCP or by changing hydrostatic pressures and temperatures. In this way, saturable absorption depends not only on the incident optical intensity but also on the laser field, which is more easily realized in the z-polarization direction. The peak positions and magnitudes of the linear, third-order nonlinear, and total OACs can be effectively adjusted with an appropriate choice of these external perturbations. Moreover, hydrostatic pressures and temperatures affect these OACs in an opposite way. This opens a promising route to design new and efficient impurity-based devices manipulated by external perturbations.

The Cr-Nb alloyed layer formed on the surface of low carbon steel by double glow plasma surface alloying could improve the corrosion resistance of the substrate. The morphology and microstructure of the layer were investigated by scanning electron microscopy, energy dispersive spectrometer and X-ray diffraction. The average thickness of the alloyed layer is approximately 18 µm. A uniform and dense Cr-Nb alloyed layer had been synthesized without any cracks and holes on the surface of low carbon steel. The corrosion behavior of the alloyed layer was evaluated by polarization experiments in 3.5 wt% NaCl solution using a CHI660D type electrochemical workstation. Potentiodynamic polarization and electrochemical impedance spectroscopy were applied to evaluate the corrosion resistance of the alloyed layer. Compared with the substrate, the Cr-Nb alloyed layer exhibited higher corrosion potential, lower corrosion current density and larger charge transfer resistance. The result presents that Cr-Nb alloyed layer has significantly modified the corrosion resistance of low carbon steel.

The longitudinal optical conductivity in bilayer graphene is calculated using the dielectric function by defining the density operator theoretically, while the effect of the broadening width determined by the scattering sources on the optical conductivity is also investigated. Some features, such as chirality, energy dispersion and density of state (DOS) in bilayer graphene, are similar to those in monolayer graphene and a traditional two-dimensional electron gas (2DEG). Therefore, in this paper, the bilayer graphene optical conductivity is compared with the results in these two systems. The analytical and numerical results show that the optical conductivity per graphene layer is almost a constant and close to e 2 / ( 4 ℏ ) , which agrees with the experimental results.

The oxidation behavior of γ-TiAl with Ta surface coating fabricated by double glow plasma surface alloying technology was investigated by thermogravimetric method. Oxidation experiments were carried out at 750 °C and 850 °C in air for 100 h. The modification layer was comprised of deposition layer and diffusion layer, which metallurgically adhered to the substrate. Tantalum element decreased with the case depth. The oxidation morphology was studied by a scanning electron microscope and X-ray diffraction. The results highlighted that in the oxidizing process of the oxidation, the phase containing Ta-richer may restrain diffusing outward of the element Al in the matrix. Ti diffused outward, and formed the TiO2 scales, while the middle layer was rich in Al, and formed the continuous Al2O3 scales after oxidation, which was effective to prevent further infiltration of oxygen atoms, and as a result the oxidation resistance increased immensely.

To solve the poor tribological property of the γ-TiAl alloy, the duplex treatment of plasma carburisation on plasma alloying γ-TiAl with tungsten was conducted by double glow plasma surface alloying technique. The results indicated the alloying layer consisted of TiC and W2C phase, metallurgically adhered to the substrate. In terms of the H/E and H3/E2 ratios, the duplex treated specimen was nearly three times larger than the untreated specimen. The wear property of the specimens was tested on a pin-on-disk tribometer by rubbing against Si3N4 ceramic ball. The wear rate of the duplex-treated specimens is 1·056×10−4 mm3 N−1 m−1, which is only 25·9% of that of the untreated specimens. The relationship between alloying layer mechanical property and wear resistance indicates that the carbide phase formed within the alloying layer contributes to the improvement of the wear performance.

Tantalum coating was successfully prepared onto Q235 low carbon steel substrate by a double glow plasma technique to improve the corrosion resistance. The microstructure and chemical composition of the coating were investigated by SEM, energy dispersive spectrometry and X-ray diffraction. The tantalum coating consisted of deposition layer, and the diffusion layer is ∼33 μm in thickness, metallurgically adhered to the substrate. Nanoindentation tests were used to measure nanomechanical properties of the coating and the substrate. A comparative study of the corrosion resistance of the bared and tantalum coated steel was conducted by electrochemical measurements in 3·5 wt-%HCl solution respectively. The results show that the coated samples exhibit much higher hardness and better anticorrosion performance than the uncoated ones. The excellent corrosion resistance of tantalum coated steel was attributed to the low porosity for the coating and a compact, and the stable tantalum oxidation film formed on ...

The electric field modulated electronic properties are investigated in InAs/GaSb based type II and broken-gap quantum wells. The transfer matrix method is employed to solve the Schrcidinger equation in the present of the external electric field. The wavefunctions and subband energies for electron and hole can be tuned by the external electric field. The exchange self-energy induced by Coulomb interaction can be modulated by the gate electric voltage by tuning the Fermi energy and the form-factor which depends on the overlap of the wavefunctions. Our results provide a simple way to determine the electronic properties in InAs/GaSb based quantum well system.

Zirconium (Zr) alloying layer was formed in the TC11 surface by using the double glow plasma surface alloying technique. The microstructure, surface hardness and oxidation resistance of the alloying layer were investigated by X-ray diffraction, scanning electron microscope and energy dispersive X-ray spectrometry, respectively. The results showed that the alloying layer consisted of a compact and homogeneous Ti–Zr mutual diffusion layer, and the surface alloying elements all displayed gradient distributions. The zirconium alloying layer enhanced the surface hardness by solution strengthening. The improvement of TC11 oxidation resistance was due to the formation of compact and uniform oxide scales, which was consisted of ZrO2 as the major phase and TiO2 as the minor phase.

The niobized layer was formed on Q235 low-carbon steel by double-glow plasma surface niobizing to improve its wear resistance. The microstructure, phase composition, and microhardness were determined. The friction and wear properties of the niobized samples and the untreated alloys were tested on a ball-on-disk tribometer by rubbing against GCr15 and silicon nitride (Si3N4) balls at room temperature and 400°C, respectively. The results indicated that the alloyed layer that contained a sediment layer and diffusion layer is about 35 μm in thickness, metallurgically adhered to the base metal. Niobium content was gradually decreased along the depth direction from the surface, which was similar to the change in the microhardness. The alloying layer mainly consisted of Nb, Fe2Nb, and FeNb phases. Under unlubricated sliding conditions, the friction coefficients and the specific wear rates were lower than those of the untreated carbon steel at room and high temperatures. The wear mechanism of the niobized specime...

Ocean waves are the richest texture on the sea surface, from which valuable information can be inversed. In general, the Synthetic Aperture Radar (SAR) images of surface waves will inevitably be distorted due to the intricate motion of surface waves. However, commonly used imaging algorithms do not take the motion of surface waves into consideration. Therefore, surface waves on the obtained SAR images are rather blurred. To solve this problem, an airborne SAR imaging algorithm for ocean waves based on optimum focus setting is proposed in this paper. Firstly, in order to obtain the real azimuth phase speed of dominant wave, the geometric and scanning distortion in the blurred SAR image is calibrated. Subsequently, according to the SAR integration time and wavelength of the dominant wave, a proper focus setting variation section is selected. Afterwards, all the focus settings in this variation section are used to refocus the image, which are then compared to decide the optimum focus setting for dominant wave. Finally, by redesigning the azimuth matched filter using this optimum focus setting, a well-focused SAR image for the dominant wave can be obtained. The proposed algorithm is applied to both simulation and field data, and SAR images of surface waves are obtained. Furthermore, the obtained images are compared with those obtained with a zero-focus setting. The comparison shows that the focus of surface waves is significantly improved, which verifies the effectiveness of the proposed algorithm. Finally, how to choose the appropriate focus setting variation section under different parameters and the applicability of the algorithm are analyzed.

The hot-dipped zinc–aluminum alloy coating was used to avoid galvanic corrosion problems of titanium–aluminum alloy. The microstructure and corrosion properties of the coating were investigated by scanning electron microscopy, electrochemical measurement, and immersion test. The microstructure indicated that the coating consisted of outermost layer and middle interdiffusion layer, which metallurgically combined with the substrate. The electrochemical properties indicated that the coating on the titanium alloy decreased the electrochemical potential difference of galvanic couple. The corrosion current density showed that aluminum alloy contact with the coating changed the electrode, in other words, aluminum alloy specimen turned out to be the cathode in the galvanic couple. Immersion test was carried out to evaluate the performance of coating for galvanic corrosion, results confirmed that aluminum alloy contacted with coating on titanium–aluminum alloy exhibited less surface corrosion.

The cyclic oxidation behavior of plasma surface chromising coating on titanium alloy (Ti–6Al–4V) was researched in air at 650 °C, 750 °C and 850 °C. A NiCrAlY coating was prepared by multi-arc ion plating as a comparison. The surface morphologies, microstructures and phases of both coatings before and after oxidation were investigated using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffractometry (XRD). The results show that the chromising coating consisted of an outer layer of loose Cr deposition, an intermediate layer of compact Cr deposition and an inner Ti–Cr mutual diffusion layer. The multilayer oxide scales formed in the oxidation process, which has the better cyclic oxidation resistance compared with NiCrAlY thermal barrier coating. However, the brittleness of Ti(Cr, Al) 2 laves phase resulted in spallation of oxide scales at 750 °C and 850 °C.

Herein we obtain CdSe-TiO 2 composite, graphene-CdSe composite and graphene-TiO 2 composite by using a facile hydrothermal method. The as-prepared composites are characterized by Brunauer emmett Teller (BET) surface area measurement, X-ray diffraction (XRD), scanning electron microscopy (SEM) with an energy dispersive X-ray (EDX) analysis, transmission electron microscopy (TEM), UV-vis diffuse reflectance spectra (DRS). According to the decomposition results of methylene blue (MB) solution in dark, it can be observed that the graphene-CdSe composites show a very interesting character, self-decomposition effect of MB in dark. Keywords: Graphene, CdSe, Hydrothermal, UV-vis DRS, Self-decomposition INTRODUCTION In most of the industrial wastewater treatment works, adsorption by activated carbon, advanced chemical oxidation, enhanced coagulation and photochemical process are commonly employed technologies for removal of refractory pollutants from industrial wastes. Among of them, the advance of photochemical processes has made the decomposition of synthesized refractory organics sustainable, especially with the advent of semiconductor photocatalysts.

Ships on synthetic aperture radar (SAR) images will be severely defocused and their energy will disperse into numerous resolution cells under long SAR integration time. Therefore, the image intensity of ships is weak and sometimes even overwhelmed by sea clutter on SAR image. Consequently, it is hard to detect the ships from SAR intensity images. A ship detection method based on local region power spectrum of SAR complex image is proposed. Although the energies of the ships are dispersed on SAR intensity images, their spectral energies are rather concentrated or will cause the power spectra of local areas of SAR images to deviate from that of sea surface background. Therefore, the key idea of the proposed method is to detect ships via the power spectra distortion of local areas of SAR images. The local region power spectrum of a moving target on SAR image is analyzed and the way to obtain the detection threshold through the probability density function (pdf) of the power spectrum is illustrated. Numerical P- and L-band airborne SAR ocean data are utilized and the detection results are also illustrated. Results show that the proposed method can well detect the unfocused ships, with a detection rate of 93.6% and a false-alarm rate of 8.6%. Moreover, by comparing with some other algorithms, it indicates that the proposed method performs better under long SAR integration time. Finally, the applicability of the proposed method and the way of parameters selection are also discussed.

Double glow plasma (DGP) coatings were recommended for metallic components to mitigate the damage induced by complex working conditions. In this paper, A Ti-Al alloy was coated with niobium (Nb) via a DGP process to enhance its anti-oxidation properties, wear resistance and flame retardancy. The results showed that the Nb-coated Ti-Al alloy mainly comprised Nb, AlNb2, AlMoTi2 and β-Ti phases. Room temperature sliding-friction tests indicated that the Nb-coated Ti-Al alloy exhibited a stable friction coefficient of an average value of 0.25, whilst the same value for via the uncoated Ti-Al alloy was around 0.45. High-temperature oxidation tests revealed compact oxide grains without cracks after the 100 h test, indicating good oxidation resistance. An ablation test showed that the Nb-coated Ti-Al alloy exhibited excellent flame retardancy, with the ablation time of the Nb-coated Ti-Al alloy at 1.62 times that of the uncoated Ti-Al base alloy. The alloys tribological behaviour, oxidation resistance and flame retardancy mechanisms are discussed in detail in this paper.