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Du H.X.,Xian University of Architecture and Technology | Du H.X.,Shaanxi Techno Institute of Recycling economics | Zhang J.,Xian University of Architecture and Technology | Wang L.,Xian University of Architecture and Technology | Bai X.,Xian University of Architecture and Technology
Applied Mechanics and Materials | Year: 2014

To identify the concentration of heavy metals in greenbelt soils of urban road in different functional zones, 0-15cm and 15-30cm soils were collected from south suburbs of Xi'an City. The concentrations of Cr, Pb, and Cu were determined and contamination level were assessed using single pollution index and geoaccumulation index. The results indicated that the highest contamination level was dominated by Pb and Cu. In addition, Pb was accumulated in 0-15cm soils especially, and the concentrations of three heavy metals in 0-15cm were higher than those in 15-30cm. The geoaccumulation index indicated that the contamination levels of these heavy metals in descending order was industrial area, busy roads, commercial areas, and park areas. The highest contamination degree of heavy metals were dominated by Cu, followed by Pb, which have correlation with industrial activities and traffic transport, while no Cr polluted. © (2014) Trans Tech Publications, Switzerland.


Xue Q.,Xian University of Architecture and Technology | Xue Q.,Shaanxi Techno Institute of Recycling economics | Zhao L.,Xian University of Architecture and Technology | Ding D.,Xian University of Architecture and Technology | And 2 more authors.
Kuei Suan Jen Hsueh Pao/Journal of the Chinese Ceramic Society | Year: 2016

The modified zirconia metering nozzles were fabricated with MgO-Al2O3-ZrO2 composite powders with different compositions prepared by a sol-gel method as additives. The bulk density, apparent porosity, thermal shock, compression strength, mineral phase and microstructure of zirconia metering nozzle were characterized. The results show that the bulk density decreases and the open porosity increases with increasing the mass fraction of MgO addition. The compressive strength firstly increases, and then decreases, and the residual strength ratio after thermal shock becomes greater. The addition of MgO composition in composite powders can reduce the consumption of stabilizer MgO in raw material, which produces magnesium aluminate spinel, thus leading to the decrease of the precipitation of stabilizer MgO that favors the stability degree of the modified metering nozzle. The magnesium aluminate spinel and miniature pore structure in the sintering process with uniform size and dispersed distribution and the formation of strong-bonding zirconia grains with uniform size can improve the thermal shock stability of samples and ensure the erosion resistance and scouring resistance. When the addition of MgO is 0.65% (in mass fraction), the amount of phase transition is proper and the amount of micro cracks in the sample favor the toughening of the samples, thus obtaining the optimal strength and thermal shock stability. However, the excessive phase transition causes the deterioration of performance of the samples in the absence of MgO addition. © 2016, Chinese Ceramic Society. All right reserved.


Wang C.,Xian University of Science and Technology | Huan D.,Shaanxi Techno Institute of Recycling economics
Advanced Materials Research | Year: 2011

In this paper, the analytic solutions of steady vibration of free orthotropic rectangular plate loaded with vertical steady loading on the elastic half-space was given by combining the general solution of double trigonometrically cosine series with supplementary terms with dynamic integral representations for displacements of the elastic half-space loaded with arbitrary vertical steady loading. This solution not only is four-order derivative, but also has less undetermined coefficients. It can be used to solve the problems of bending and steady vibration of orthotropic rectangular plates on the elastic half-space without be classified and be superimposed. This causes this kind of things, bending and steady vibration of orthotropic rectangular plates with four free edges on the elastic half-space, unionization, simplification and systematization. When the material is isotropic, the solutions are turned into analytic solutions of steady vibration of free rectangular plate on the elastic half-space. At last some computational examples are presented and the results are coincided with those in literatures. Then the method in this paper will be of important practical applications. © (2011) Trans Tech Publications, Switzerland.


Xue Q.-H.,Xian University of Architecture and Technology | Xue Q.-H.,Shaanxi Techno Institute of Recycling economics | Zhao L.,Xian University of Architecture and Technology | Ding D.-H.,Xian University of Architecture and Technology
Rengong Jingti Xuebao/Journal of Synthetic Crystals | Year: 2015

MgO-Al2O3-ZrO2 composite powders (mass ratio of MgO/Al2O3/ZrO2 were 10.0/41.4/48.6, 15.0/39.1/ 45.9 and 20.0/36.8/43.2 respectively) were prepared by sol-gel method using MgCl2·6H2O, AlCl3·6H2O and ZrOCl2·8H2O as starting materials and NH3·H2O as precipitant. The composite powders were investigated by X-ray fluorescence instrument, simultaneous thermal analyzer, X-ray diffractometer, laser particle size analyzer and scanning electron microscope. Research show that the decomposition process of composite powders' precursor has completed before 600℃ and the crystallization degree of composite powders increases with the rising of heat treatment temperature. At 800℃, a small amount of t-ZrO2 precipitates, meanwhile MgO and Al2O3 are still in the amorphous phase. The MgO-Al2O3-ZrO2 composite powders should have high reactivity under this condition; the chemical composition uniformity of composite powders are good, and the particle size is fine and matched with the size of zirconia raw material, as the additive of modified metering nozzle. ©, 2015, Rengong Jingti Xuebao/Journal of Synthetic Crystals. All right reserved.


Xue Q.,Xian University of Architecture and Technology | Xue Q.,Shaanxi Techno Institute of Recycling economics | Liu W.,Xian University of Architecture and Technology | Zhao L.,Xian University of Architecture and Technology | Ding D.,Xian University of Architecture and Technology
Gongneng Cailiao/Journal of Functional Materials | Year: 2015

ZrO2 sizing nozzle matrix was researched by adding stabilizer which were 2.8%MgO, 2.1%MgO and 2.2%MgO+1%Y2O3 respectively in the desilication zirconium powder. The effects of stabilizer on the composition of phase and the microstructure of ZrO2 sizing nozzle matrix before and after sintering were studied by XRD, SEM and EDS. Results showed that the content of cubic phase increased and the content of monoclinic phase decreased significantly for all samples after sintering at 1 630℃, the specise and feed ratio of stabilizer in raw materials made cubic and monoclinic phase variation of each sample were not the same after sintering; After sintering at 1 630℃, the solid solution was formed by MgO and ZrO2, with the location of MgO particle closer, the substitution degree of Mg2+ and Zr4+ was more obvious, but the diffusion and solid solution of the stabilizer were far from uniform state; For the sinteried sample combining MgO+Y2O3 stabilizer, cubic phase gained the most, and solid solution generated largest, the degree of stabilization was the highest and the combination between ZrO2 particles which have uniform size and angular shape is much close. ©, 2015, Journal of Functional Materials. All right reserved.

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