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The determination method for analyzing trace copper in vanadium alloy by flame atomic absorption spectrometry was investigated in the paper. The sample digestion method, digestion acidity, determination conditions, matrix interferences, method precision, recovery of standard addition were investigated in detail. The method precision in RSD% was 8.6%, and the average recoveries of standard addition were from 93.9% to 95.6%. The experimental results indicated that the proposed method for determination of trace copper in vanadium alloy was simple, fast, accurate, and easy to operate, which was suitable for quality control of vanadium alloy.

In this paper, an optimized p⁺ shielding 4H-SiC trench-gate metal-oxide-semiconductor field effect transistors (UMOSFETs) structure with floating regions is proposed. The p⁺ shielding region is moved down to gain a low device on-resistance and the floating regions are designed to improve the breakdown voltage in the proposed structure. Specific on-resistances of the proposed 4H-SiC UMOSFETs is 2.62 mΩ.cm² at V_GS=18 V and V_DS=10 V, compared with 4.77 mΩ.cm² for the conventional p+ shielding UMOSFETs structure with same breakdown voltage. The on-resistance and figure of merit (FOM = V_BR²/R_on) improve by 45.1% and 94.2%, respectively.

The corrosion inhibition performance of molybdate and molybdate compound corrosion inhibitor of carbon steel in seawater were tested using weight loss method, electrochemical polarization curve, and the quaternary compound molybdate corrosion inhibitor were made sure through the experiments. The experiment results show that the compound corrosion inhibitors have obvious synergistic corrosion inhibition effects in the proportion of 40 mg/L molybdate, 10mg/L HEDP, 4mg/L Zn2+ and 50 mg/L glucose acid salts.

The LaNiO₃ nanoparticles were prepared by a sol-gel process. The LaNiO₃ nanoparticles were characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-Vis diffuse reflectance spectroscopy (DRS). XRD and SEM demonstrate the successful synthesis of single phase perovskite LaNiO3 and an average grain size of 80 nm in diameter. It was found that the as-prepared LaNiO₃ shows strong visible-light absorption with absorption onset of 545 nm, indicating a narrow optical band gap of 2.28 eV. Consequently, LaNiO₃ nanoparticles show high visible-light photocatalytic activity for decomposition of methyl orange in comparison with the commercial Degussa P25. The photocatalytic experiment shows the high photocatalytic activity for the decomposition of methyl orange under visible-light irradiation, which is attributed to the strong visible-light absorption.

The characterization in microstructure, morphology and oxidation behavior of three iron-based coatings by Supersonic Arc Spraying (HVAS), were investigated by XRD, FESEM, EDS and thermal exposure in furnace in this paper. It is indicated that the three coatings are typical layer and compact structure. The coatings are composed of Fe (s.s) phase and kinds of ferric oxides, chrome carbides and/ or intermetallic phase distributing along the interface of lamellar layers. More Cr and Ti, Al elements can alternate the diameter and morphologies of the holes, resulting from the formation of oxides, carbides and intermetallic phase. The results indicate that SXTiAlC coating shows the most excellent oxidation resistance with 2.70 mg·cm^-2 in mass gain, while that are 88.08 mg·cm^-2 and 16.64 mg·cm^-2 after 100 h thermal exposure at 800°C for LX88A and SXHCrA coatings, respectively. The oxidation behavior is discussed.

Radiometric calibration of synthetic aperture radar (SAR) is an important work related to pixel values and the backscattering coefficient of ground targets. With a consideration of the difference between near space and spaceborne, airborne platforms, this paper proposes the radiometric calibration method which is applicable to near space platform. A radiometric calibration model of near space SAR is established, and it is analyzed and validated by experimental data.

To analyze the relationship of brake performances and its influence factors, a kind of tire drum test-bed was designed. The gradation principle of flywheels was proposed based on the double multiplication method and an inertial system with eight steps of flywheels was put forward. The inertia-mass of tire load ranging 400 from 5000 kilograms was divided into 256 levels with the accuracy of ±10 kilograms. The dynamics simulation model was built using SOLIDWORKS and ADAMS. The program of acceleration and brake testing were schemed. The feasibility and accuracy of design methodology of test-bed inertial system were verified by the comparison analysis of simulation and road test. The accurate matching between the moment of inertia of test-bed inertial system and tire load was realized.

A kind of conductive composite material for the bipolar plate of proton-exchange membrane fuel cells (PEMFC) was fabricated by the hot-pressure molding with graphite powders and polyphenylene sulfide (PPS) resin powders. The influencing factors including PPS resin content, molding pressure and molding temperature, and temperature holding time on the conductivity, flexural strength and density of the composite were investigated. It was found that the perfect conditions for the fabrication of bipolar plate were that the PPS resin content was 25%wt, the forming pressure was 20 MPa, the mold temperature was 320°C and the holding time was 25 min.

The application of Annular Electromagnetic Stirring (A-EMS) for production of high-quality slurry has been examined. Al-11%Zn-3%Mg-1%Cu-0.13%Zr alloy was used to investigate the effect of A-EMS at various temperatures above liquidus on structure refinement. The results indicate that the grain size was reduced greatly and the homogeneous structure was achieved. Instead of the case in tradition, the nucleation particles gradually formed and the enhanced grain refining efficiency can be mainly attributed to an instantaneous nucleation of numerous heterogeneous nucleation of Al₃Zr in the superheating melt under A-EMS.

In order to provide theory basis and experimental evidence for optimizing milling parameters, the cutting force prediction models for milling of Ti6Al4V with uncoated cemented carbide tool were built based on single factor method. The significances of the cutting force prediction models were checked. The effects of milling speed, feed per tooth, milling depth and milling width on cutting forces were also studied. The results show that the built prediction models can be applied effectively to predict the cutting forces in milling of Ti6Al4V in the experiment parameters range. Milling depth has highly obvious influence on cutting forces among these milling parameters. The cutting forces decrease with the milling speed increasing, and increase with feed per tooth, milling depth and milling width.