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The dust control basis of fully mechanized mining face is clear dust source characteristics. In view of the problem of unclear dust source and unknown distribution characteristics in the working area of 7.8 m large fully mechanized mining face, the fully mechanized mining face of Shendong Bulianta Coal Mine is selected as the The research object adopts the method of combining numerical simulation and field measurement to study the dust migration law based on the single action and joint action of the two main dust sources of shearer cutting coal and column moving frame, and obtains the dust migration law. According to the characteristics, the distribution of respirable dust concentration in the breathing zone of personnel in the vicinity of the shearer was further analyzed. The results show that the dust produced by dropping the column and moving the frame has the greatest impact on the dust concentration in the operator’s area. The maximum value of the respirable dust concentration in the operator’s area when cutting coal downwind and upwind is in the middle of the shearer, and originates from the shearer cutting coal. The proportions of dust source and column-moving dust source were 44.50% and 76.69%, respectively. The dust traceability research can provide a theoretical basis for the targeted management of dust in fully mechanized mining face with large mining height.

BACKGROUND The injection of nanoscale zero valent iron particles (nZVI) into groundwater has been recently developed as an in-situ groundwater remediation technology. Most researches focused on how to remove a single type pollutant and the related mechanism. However, cases on the coexisting multiple pollutants in groundwater should not be ignored. OBJECTIVES To synthesize the bentonite-supported nanoscale Fe/Ni bimetals(B-Fe/Ni), in order to remove typical pollutants of trichloroethylene (TCE) and hexavalent chromium[Cr(Ⅵ)] which exhibit high reactivity and are more stable to remediate contaminated water. Also, to assess the performance of B-Fe/Ni on the removal of coexisting TCE and Cr(Ⅵ) and to determine the reaction mechanism. METHODS B-Fe/Ni was synthesized by one-step method and the batch experiments were conducted on the removal of TCE coexisted with different concentration of Cr(Ⅵ) by B-Fe/Ni. The samples of B-Fe/Ni were characterized before and after the reaction, and the contents of TCE and Cr(Ⅵ) were also monitored. RESULTS B-Fe/Ni can efficiently remediate Cr(Ⅵ) and TCE in water. B-Fe/Ni (1 g/L) could completely remove Cr(Ⅵ) (50 mg/L) in 2 h in the presence of coexisting TCE (0.1 mmol/L). However, the degradation rate of TCE by B-Fe/Ni was decreased with increased initial concentration of Cr(Ⅵ) (0, 10, 30, 50 mg/L). According to TEM-EDS and XPS for B-Fe/Ni before and after reaction, it is shown that Fe-Cr co-precipitation from the fast interaction of B-Fe/Ni with Cr(Ⅵ) occupied the reactive sites on the surface of B-Fe/Ni, mitigating the degradation of TCE. According to the final products of TCE degradation, it is shown that TCE was completely dechlorinated. CONCLUSIONS B-Fe/Ni is suitable for the remediation of groundwater combined pollution. In practical applications, it is necessary to consider the mutual influence of multiple pollutants and select the appropriate reagent dosage and injection method. The proposed method has important theoretical significance and application for the development of ZVI repair technology.

The properties of cathode materials play an important role in the development and application for lithium ion batteries. However, their phase transition, low conductivity and side reaction with electrolyte restrict the further improvement of battery performance. Coating is one of the effective techniques to overcome these problems. This paper focuses on the influence of surface coating on the properties of cathode materials for lithium ion batteries. The research progress of various coating materials was summarized. The modification mechanism of coating materials was also elaborated. And the future development trend of coating materials was proposed, for example, exploring continuously new coating materials with excellent performance, investigating in depth coating mechanism, and optimizing further coating technologies.

Background/Aims: Chronic renal failure (CRF) is often accompanied by increased oxidative stress and euthyroid sick syndrome (ESS). The cause of ESS is unknown, and it is unknown whether there exists a link between oxidant stress and ESS in CRF patients. Therefore, we aim to investigate oxidative stress and type 1 deiodinase (DIO1) expression, which plays the key role in the ESS in CRF patients. Methods: In-patients with CRF were divided into the two group: Group 1 is ESS patients consisting of 60 patients with low free triiodothyronine (FT3) and Group 2 consisting of 60 patients with normal FT3. Group 3 consisted of 60 healthy volunteers recruited as controls. The baseline clinical parameters of patients were evaluated with standard routine methods in a clinical laboratory. Serum levels of 8-isoprostane and DIO1 were measured by enzyme-linked immunosorbent assay (ELISA). Multiple regression analysis was used to analyze the relationship between oxidative stress, DIO1 and FT3. Results: The concentrations of serum 8-Isoprostane in Group 1 and Group 2 were substantially higher than that of Group 3 (p< 0.05), however there was no significant difference between Group 1 and Group 2 (p=0.516). The serum DIO1 level was higher in Group 2 than in Group 1 and Group 3 (p< 0.001). Multivariate linear regression analysis revealed that the DIO1 concentration and FT3 level were not associated with the concentration of serum 8-Isoprostane. Conclusions: CRF patients showed elevated oxidative stress. The CRF patients without ESS showed higher expression of DIO1 than patients with ESS and the control group. The concentration of serum 8-Isoprostane was not correlated with FT3 and DIO1 levels.

Powder solid sampling atomic emission spectrometry is a simple sample pretreatment method with high sensitivity, low detection limit, and little environmental pollution. This method has been applied to the simultaneous analysis of trace Ag, B and Sn in geochemical samples. However, the serious matrix effect limits the application of this method. Based on the Scanning Electron Microscopy (SEM) technique, the differences in the composition of the reaction products at different times for specific formulations and different samples was compared. Combined with the evaporation curve to reverse the reaction process, a carrier buffer suitable for different types of geochemical samples was developed. In order to realize the improvement of the arc burning process, K2S2O7 and NaF were used as flux during preparing carrier buffer to catalytically decompose the matrix. Synergizing with PTFE and sedimentation S promotes rapid evaporation of analyzed elements in various forms. The formation of Al2O3-SiO2-CaO-BaO mutual melt lowers the Tammann temperature and can absorb matrix oxides in-situ, suppressing the interferences. Compared with the available method, the sensitivity increased by 1.2 times, and the precision, accuracy and detection limit are superior to a number of geochemical survey specifications.

In order to solve the precise heading measurement problems of low cost rotor unmanned aerial vehicle(UAV), a method of heading measurement system based on MEMS sensors is designed in this paper. The system is composed of MEMS IMU, electronic compass and microprocessor ST32F407. The gradient descent algorithm with lower computational complexity and the improved second-order complementary filtering algorithm are used to fuse the data of the electronic compass and IMU which have the complementary characteristics. Then the coordinate system with quaternion is converted to calculate aircraft heading information. Through the testing experiment of heading measurement system on the rotor UAV, the analysis results show that without external information aided，the system could solve the problem of interference measurement and heading noise, and it can meet the requirements of the heading information of the small rotor UAV.

A wavelet modulation strategy applied to a quasi-Z-source inverter was proposed. The regulating range of the shootthrough duty ratio could be increased by changing the locations of the sampling points set using traditional wavelet-modulation. The proposed modulation strategy divided the shoot-through zero vector into two portions, which were then individually inserted into both ends of the sampling time. Under the proposed strategy, the quasi-Z-source inverter could obtain a theoretical maximum constant shoot-through duty ratio without any extra switching frequencies. In addition, the proposed strategy was compared with traditional modulation strategies used in quasi-Z-source inverters. The boosting capacity, efficiency, harmonic and modulation ratio of the different modulation strategies for quasi-Z-source inverter were analyzed thoroughly. Finally, the performance of the proposed method was verified by simulation. Both the simulation results and theory verify that the strategy can reduce harmonic, increase voltage utilization rate, and enhance the boosting capacity.

The precipitation behavior and distribution of second phase particles in conventional grain-oriented silicon steel during manufacturing process were observed by field emission scanning electron microscopy, and the average particle size, the areal particle density, and the Zener factor were statistically analyzed. The results show that the samples mainly contain two kinds of precipitates:A class is the (Cu,Mn)S composite precipitates with the average size of 1μm; B class is the Cu2S precipitates with the size of 10-30nm, the key inhibition effect is produced by Cu2S. Hot rolling leads to a large amount of fine second phase particles precipitation, which has the minimum average particle size and the highest areal density; in the manufacturing process before high temperature annealing, the average particle size is increasing and the areal density is decreasing; in the process of high temperature annealing, with the decrease of volume fraction of precipitates, the inhibition ability exhibits reducing trend,obvious aggregation occurs at 960℃,secondary recrystallization will happen when Zener factor A decreases below the critical value of 0.19nm-1, and the residual particles will not produce valid inhibition effect.

The basic features of A-100 steel, such as relationship between cogging process and mechanical properties, relationship among the forging process, grain size and mechanical properties, secondary hardening, and fatigue properties were discussed. The high-temperature homogenization and high deformation at first step technique were developed on the foundation of multiple upsetting and stretching, high forging ratio technique used for 300M steel, and became the technique foundation of cogging process in A-100 steel. The fracture toughness of A-100 steel was tended to be influenced by hot working process. The grain size grew heavily, and mixed grain structure was appeared after heating at 1140℃ and above with deformation amount below 20%, the fracture toughness was also decreased. The secondary hardening performance of A-100 steel was changed after the deformation at low temperature. The tensile strength peak temperature was changed to 468℃,the tensile strength was decreased slowly when over aging. A-100 steel was cyclic hardened, and its fatigue crack growth properties were better than 300M steel. The high cycle fatigue property was heavily deteriorated when tested in 3.5%NaCl solution.

The content of the same element in separate rare polymetallic ore processing samples is different, and the content of each element in the same sample is also different. For example, the content of niobium, tantalum, lithium, and beryllium in tailings and ore is only a few tens to several hundred μg/g, but in the concentrate these elements have contents of several percent to several percent and associated elements such as potassium and sodium in different samples are also quite different. Determination of niobium, tantalum, lithium, and beryllium by Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) commonly involves three acid or four acid decomposition of samples. This method was mostly used to determine the lower content of niobium, tantalum, lithium, and beryllium in tailings, ore and some of ore samples, and the same determination system only analyzes one or two elements. The niobium-tantalum polymetallic ore was dissolved with HF-HCl-HNO3-HClO3-H2SO4 and extracted by 3-4 drops of mixed hydrofluoric acid, 5% sulfuric acid, and 5% hydrogen peroxide, instead of conventional organic acids (tartaric acid, etc) extraction system, which makes it possible that simultaneous ICP-OES determination of niobium, tantalum, lithium, beryllium, potassium, sodium, rubidium, iron, titanium and other elements in different stages of rare metal ore beneficiation test products is possible. The spectral line intensity shows a good linear relationship when the concentration of elements is 0-500 μg/mL. The relative standard deviation is 0.37%-4.77% (n=6). The method has improved the efficiency of the analysis of various elements in the whole process sample and has been applied in the sample analysis of the smelting process.

This paper presents the development status and tendency of quantum dot sensitized solar cells. Photoanode research progress and its related technologies are analyzed in detail from the three ways of semiconductor thin films, quantum dot co-sensitization and quantum dot doping, deriving from the approach that the conversion efficiency can be improved by photoanode modification for quantum dot sensitized solar cells. According to the key factors which restrict the cell efficiency, the promising future development of quantum dot sensitized solar cells is proposed,for example,optimizing further the compositions and structures of semiconductor thin films for the photoanodes, exploring new quantum dots with broadband absorption and developing high efficient techniques of interface modification.

The superplastic tensile tests were carried out for 7B04 Al alloy under a temperature range of 470-530℃ at a strain rate range of 0.0003-0.01s-1. Then,the superplastic deformation behavior and deformation mechanism of the material were investigated. The results show that with the increase of temperature and decrease of strain rate, the flow stress of 7B04 Al alloy is decreased and the elongation is increased.When the deformation temperature is at 530℃ and the strain rate is 0.0003s-1, the elongation reaches the maximum value of 1105%, which indicates that at this process parameter the optimal superplasticity is obtained; the strain rate sensitivity index m value is above 0.3 and increases as the temperature going up; when the deformation temperature is at the range of 500-530℃, the m value is above 0.5,the superplastic deformation mechanism of 7B04 Al alloy predominated by grain boundary sliding; the superplastic deformation activation energy Q value is 190kJ/mol which indicates that the superplastic deformation is significantly controlled by the intercrystalline diffusion; the liquid phase will be produced along the grain boundaries of 7B04 Al alloy during superplastic deformation,which can enhance the superplasticity with a moderate amount.

Based on the characteristics of CO2 at high temperature, material and energy models for CO2 using in a dephosphoriza-tion converter were established to verify the feasibility of CO2 for oxidation reactions. Based on practical working conditions in a facto-ry, the effects of CO2 on the converter temperature and gas were studied. It is discovered that the CO2 ratio can be controlled within 28%, the oxygen consumption can be reduced by 16%, and the CO ratio in the gas can be increased by about 12% when the scrap ratio is 8% and the utilization ratio of CO2 is 85%. Besides, as the utilization ratio of CO2 increases, the semi-steel temperature of the converter gradually decreases, and the oxygen consumption also lowers.

Nanoscale zero-valent iron (nZVI) is a newly developed method for in-situ remediation of groundwater in recent years. To overcome easy oxidation and aggregation, modification on nZVI is widely adopted. In addition, the ubiquitous natural organic matters (NOM) in water also affect the scatter and reaction activity of nZVI. Therefore, it is of significance to study the aggregation effect of different kinds of nZVI in water by in-situ measurement method. Besides commercial nZVI (RNIP), normal nZVI, carboxymethyl cellulose coated nZVI (C-nZVI) and bentonite supported nZVI (B-nZVI) was synthesized. Nano particle size/Zeta potential analyzer based on the Dynamic Light Scattering (DLS) technique, Transmission Electron Microscope (TEM) and UV-Vis spectrum of sedimentation were employed to characterize the aggregation behavior of above four types of nZVI in the presence or absence of humic acid (HA), a representative NOM. The results showed that the dispersion stability of C-nZVI and B-nZVI was improved significantly after modification and the aggregation precipation was suppressed. And size distribution of aggregates stabilizes at below 1000 nm. Humic acid adsorbed onto the surface of nanoparticles, which can increase the electrostatic force to prevent aggregation of nZVI. The effect of HA on B-nZVI is most obvious for B-nZVI aggregates with diameters below 100 nm and the sedimentation was very slow, indicating the dispersion performed the best among all kinds of nZVI. It can be concluded that the combination of DLS technique and TEM to characterize nanoparticles is a valuable approach for more comprehensive information.

The current standards related to live working provide no determined path for equal potential working, in which only safety distance is referred, so that the works are often executed relying on the line maintenance experience. As high-voltage and strong space electrical field intensity exist in 1000 kV ultra-high voltage transmission lines, the real-time safe distance measurement is difficult to be conducted and the exhaustive full-scale experiments are difficult to accomplish due to the varied true tower models and lines. Simulation calculation is aroused for improving the efficiency of safety distance calculation and safety path planning during the process of importing and exporting the potential according to the different kind of tower and the actual line situation. Here, with the cup type iron tower and hanging basket mode, the electrical field intensity in and outside of screening clothes at different part of body while climbing tower and during equal-potential process are calculated, and then the safety distance, the combination gap, and the optimal path planning are carried out. The simulation results demonstrate that electrical field intensity meet safety requirements using the proposed planning path, which enriches the theoretical basis for the safety operation of ultra-high voltage live working.