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A method based on a QuEChERS sample preparation approach coupled with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was established to determine six aflatoxins (B1, B2, G1, G2, M1, M2) residues in grains. Samples were extracted with acetonitrile –0.1% formic acid aqueous solution (84 : 16, v/v), followed by purifying with PSA, and determined by UPLC-MS/MS in multiple reaction detection mode with 0.1% formic acid-acetonitrile as mobile phase. The correlation coefficients of the standard curves of the six aflatoxins were all greater than 0.99, showing good linearity. The recoveries were 80.83%~117.5%, and the relative standard deviations (RSD) were 1.53%~15.59%. The matrix effects of six aflatoxins were 0.81~1.12 in different varieties of grains. The accuracy and precision of this method meet the requirements of relevant standards, and have the advantages of simple pretreatment technology, good purification effect and high precision determination, which could be suitable for the quantitative analysis of six aflatoxins in wheat, rice, corn, mung bean and red bean samples.

In order to maximize the total spectrum efficiency and improve the Quality of Experience (QoE) on Elastic Optical Network (EON), an adaptive modulation method based on Deep Neural Network (DNN) is proposed. Firstly, the network transmission quality in optical fiber is estimated. Then, the route length, hop number and video quality are taken as the three parameters of the request characteristics, and the deep learning method is adopted to selected the modulation system with the maximum spectrum efficiency according to the desired QoE of each requirement. The simulation results show that the average spectral efficiency of the proposed method is 51%and 32%higher in National Science Foundation (NSF) network than that of distance adaptive method and integer programming method, and 43%and 29%higher in China Network (CN) backbone network. In addition, the blocking probability of the proposed method is 0.01 lower than that of the distance adaptive method and integer programming method.

The effects of cooling rate and Si on the microstructure and corrosion property of the Zn-5Al-0.1 RE alloy were studied by scanning electron microscopy-energy dispersive spectrometry, X-ray diffraction, neutral salt spray test and polarization curves. The results show that Zn-5Al-0.1RE-xSi alloys are composed of primary η-Zn phase and η-Zn + α-Al eutectic structure, and the former is uniformly distributed on the adjacent η-Zn + α-Al entectic cells. The reduction of cooling rate and the addition of Si make the grain size increase and the boundary area per unit alloy area decrease; at the same time, the corrosion resistance is improved. The corrosion resistance of the Zn-5Al-0.1 RE-xSi alloys is dependent on their solidification structure and the relative amount of corrosion products including Zn5(OH)8Cl2·H20 and ZnO.

Zn-11%Al, Zn-11%Al-1.5%Mg, Zn-11%Al-3%Mg and Zn-11%Al-4.5%Mg alloy coatings were obtained by dipping pure iron in the alloy bath at 510℃ for different immersion time. The effects of Mg content on the solidification structure of the Zn-11% Al coating and the growth of the Fe-AI intermetallic layer in the alloy coating were investigated by X-ray diffraction, scanning electron microscopy and energy dispersive spectrometry. The results show that the solidification microstructure of the Zn-11% Al alloy coating is composed of Al-rich phase and Zn/Al ternary eutectic. With the increase of Mg content in the Zn-11% Al-x% Mg alloy, Zn/Al/MgZn2 ternary eutectic, blocky MgZn2 phase and AL/MgZn2 binary eutectic occur gradually. The intermetallic layers in the Zn-11% Al alloy coatings with different amounts of Mg consist of Fe2Al5Znx phase and FeAl3Znx phase, and the thickness of the inter-metallic layer increases with the prolongation of immersion time. The increase of Mg content in the hot dip bath reduces the growth-rate index and the growth rate of the intermetallic layer. At the beginning of the hot dip process, a compact and stable Fe-Al alloy layer in the Zn-11% Al alloy coating form on the iron surface. After immersing for 120 s, the Fe-Al intermetallic layer is instable and broken because of diffusion path movement. Mg element in the Zn-11% Al-x% Mg alloy can significantly delay the time of liquid zinc into the Fe-Al alloy layer, which makes the Fe-Al alloy layer be more stable and compact.

The solubility of silicon in a Zn-50%Al-xFe-ySi(in atomic fraction) molten bath and the content of silicon in a Zn-30%Al-2%Fe-xSi(in mass fraction) molten bath corresponding to the appearing of τ5 slag phase and the disappearing of FeAl3 phase were calculated at different temperatures using the Thermo-Calc software. At the same time,the solubility of silicon in liquid phase in the Zn-50%Al-xFe-ySi alloy and the phase equilibrium relationship of the Zn-30%Al-2%Fe-xSi alloy were experimentally determined by using the equilibrium alloy method. The results show that the calculated solubility of silicon in liquid phase in the Zn-50%Al-xFe-ySi system at 540,560,580,600 and 620℃ are 0.82%,0.95%,1.11%,1.28% and 1.47%,respectively,which agree well with the experimental data. When the temperature of the molten bath is 580,600,and 620℃,the calculated content of silicon in the Zn-30%Al-2%Fe-xSi alloy corresponding to the appearing of τ5 phase in the molten bath is 0.6%,0.72% and 0.84%,and the values corresponding to the disappearing of FeAl3 phase are 1.12%,1.22% and 1.34%,respectively,which agree basically with the experimental results.