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Elevated-temperature tensile deformation and fracture behavior of particle-reinforced PM 8009Al matrix composite

Chen Shuang, Chen Guoqiang, Gao Pingping, Liu Chunxuan, Wu Anru, Dong Lijun, Huang Zhonghua, Ouyang Chun, Zhang Hui

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2021

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Vol. 69, nr 5

art. no. e138846

EN

Tensile tests of 8009Al alloy reinforced with SiC and Al₂O₃ particles fabricated by powder metallurgy (PM) were conducted at temperatures of 250–350°C and strain rates of 0.001–0.1 s⁻¹. The ultimate tensile strength and yield strength of the samples decreased while the temperature and strain rate increased. The elongation slightly decreased at first and then increased with growing temperature because of the medium-temperature brittleness of the alloy matrix. When the strain rate was 0.1 s⁻¹, the elongation of the 8009Al/Al₂O₃ composites always decreased with an increase in temperature because of the poorly coordinated deformation and weak bonding between the matrix and Al₂O₃ particles at such a high strain rate. The work-hardening rates of the composites sharply increased to maxima and then decreased rapidly as the strain increased. Meanwhile, the 8009Al/SiCₚ composites displayed superior UTS, YS, elongation, and work-hardening rates than those of the 8009Al/Al₂O₃ composites under the same conditions. Compared to 8009Al alloys reinforced with spherical Al₂O₃ particle, 8009Al alloys reinforced with irregular SiC particles exhibited a better strengthening effect. The fracture mechanism of the 8009Al/SiCₚ composites was mainly ductile, while that of the 8009Al/Al₂O₃ composites was primarily debonding at the matrix–particle interfaces in a brittle mode.

2

Photostability of TiO2-Coated Wool Fibers Exposed to Ultraviolet B, Ultraviolet A, and Visible Light Irradiation

Tang Qi, Zhang Hui, Han Ye, Wang Dou, Wu Hailiang

Autex Research Journal

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2021

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Vol. 21, no. 1

1--12

EN

This study is to investigate the role of the coating of TiO2 nanoparticles deposited on wool fibers against high-intensity ultraviolet B (UVB), ultraviolet A (UVA), and visible light irradiation. The properties of tensile and yellowness and whiteness indices of irradiated TiO2-coated wool fibers are measured. The changes of TiO2-coated wool fibers in optical property, thermal stability, surface morphology, composition, molecular structure, crystallinity, and orientation degree are characterized using diffuse reflectance spectroscopy, thermogravimetric analysis, scanning electronic microscopy, energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, and X-ray diffraction techniques. Experimental results show that the tensile properties of anatase TiO2-coated wool fibers can be degraded under the high-intensity UVB, UVA, and visible light irradiation for a certain time, resulting in the loss of the postyield region of stress–strain curve for wool fibers. The coating of TiO2 nanoparticles makes a certain contribution to the tensile property, yellowness and whiteness indices, thermal stability, and surface morphology of wool fibers against high-intensity UVB, UVA, and visible light irradiation. The high-intensity UVB, UVA, and visible light can result in the photo-oxidation deterioration of the secondary structure of TiO2-coated wool fibers to a more or less degree. Meanwhile, the crystallinity and orientation degree of TiO2 coated wool fibers decrease too.

3

Effect of turning-induced initial roughness level on surface roughness and residual stress improvements in subsequent burnishing

Zhang Peirong, Du Jin, Zhang Hui, Su Guosheng, Shen Xuehui, Huang Weimin, Liu Zhanqiang

Archives of Civil and Mechanical Engineering

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2020

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Vol. 20, no. 3

241--253

EN

The hydraulic support column of comprehensive mining equipment is the most important part, subjecting to corrosion, wear and collision. The scrapped columns are restored by laser cladding to replace plating process for enhancing service life. All that is required after laser cladding is subtractive machining to improve the surface quality of the laser cladded coatings. This work focused on the remanufacturing machining strategy for re-contouring the laser cladding restored columns. First, surface roughness model of the laser cladded coatings by turn-burnishing was presented based on the surface generation mechanism. Then the effect of turning-induced roughness level on the surface roughness improvements by subsequent burnishing is addressed. Results indicated that the reduction of surface roughness by burnishing showed positive correlation with the feed in initial turning with conventional inserts, while was negatively correlated with the feed in initial turning with wiper inserts. In addition, the initial turning-induced surface roughness level generated great influence on the residual stress improvement in subsequent burnishing. Based on the findings, proper remanufacturing machining strategies for re-contouring the laser cladding-restored hydraulic support columns were presented.

4

Effect of iodine value of sodium fatty acids on flotation of collophanite

Liu Runzhe, Zhang Guofan, Zhang Hui, Liu Lifen, He Lin, Chen Yanfei

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 3

770--778

EN

The sodium fatty acids were firstly prepared by fatty acids with different iodine values which were from surfactant extraction using soybean oil fatty acid as raw material in this study. Effects of iodine value of sodium fatty acids on the flotation of collophanite were then investigated by flotation tests, contact angle measurements, adsorption tests, Krafft point measurements, foaming ability tests, and the resistance to the hard water measurements. Results show that the final flotation recovery was directly proportional to the iodine value of sodium fatty acid. Sodium fatty acid with higher iodine value has higher solubility and dispersity in the solutions, and stronger foaming ability and resistance to hard water. After interacting with collophanite, sodium fatty acid with higher iodine value made the mineral more hydrophobic, thus contributing to better flotation performances.

5

3D-RVSP experimental study above a carbonate outcrop for coal resource exploration

Hu Mingshun, Pan Dongming, Li Juanjuan, Zhang Hui, Dong Shouhua, Chen Shenen, Xu Yongzhong

Acta Geophysica

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2019

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Vol. 67, no. 1

95--107

EN

In the areas where carbonate rocks expose to the near surface, there are several intractable issues in conventional surface seismic, including (1) weak reflection energy, (2) complex wave field and (3) serious static correction. Therefore, the seismic imaging result suffers significantly. However, RVSP is able to achieve reflected data with high quality since it generates seismic waves in borehole and receives seismic waves at the surface. In order to verify the applicability of RVSP technique in complex areas, this study carried out a 3D-RVSP seismic experiment in Wulunshan coal field, southwest China. Compared with the surface seismic data, RVSP data show higher signal-to-noise ratio, wider frequency band and weaker surface wave interference. In addition, two imaging methods (conventional CDP transform stack and novel equivalent-surface conversion) were implemented for RVSP data imaging. The imaging results show that the smaller and deeper structures can be revealed better by equivalent-surface conversion method than by CDP transform stack method. Hence, this study demonstrates that RVSP is an efficient method applied in the area with complex surface condition.

6

Pharmacokinetics in rat plasma and tissue distribution in mice of galangin determined by UHPLC–MS/MS

Ye Weijian, Sun Wei, Chen Ruijie, Wang Zhe, Cui Xiao, Zhang Hui, Qian Shuyi, Zheng Qi, Zhou Yangfeng, Wan Jiafeng, Xu Jiali, Wang Xianqin, Zhou Yunfang

Acta Chromatographica

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2019

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Vol. 31, no. 2

120--125

EN

Galangin (GAL), the major bioactive flavonol extracted from Alpinia officinarum Hance (Zingiberaceae), has attracted much attention due to its multiple biological activities. To develop a fast, reliable, and sensitive ultrahigh-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) method for the quantification of GAL in rat plasma and mouse tissues. UHPLC–MS/MS using electrospray ionization operating in negative-ion mode was used to determinate GAL in 18 rats receiving three doses of GAL (2 and 9 mg/kg by intravenous injection, 5 mg/kg by oral administration), with six rats for each dose. Blood samples were collected at 0.0333, 0.25, 0.5, 1, 2, 4, 6 and 8 h. A total of 25 mice received 18 mg/kg GAL by intraperitoneal injection. Liver, heart, lung, spleen, brain, and kidney tissue samples were collected at 0.25, 0.5, 2, 4, and 6 h. The precision of the method was better than 12.1%, while the accuracy ranged from −4.8% to 8.1%. The results of pharmacokinetics demonstrated rapid GAL absorption (tmax of 0.25 h), fast elimination (t1/2 <1.1 h) after three different dosages, and an absolute bioavailability of ~7.6%. Tissue distribution analysis revealed abundant GAL in liver, kidney, spleen, and lung and smaller amounts in brain. The developed method proved fast (3 min), efficient, and reliable, with high selectivity for the quantitative analysis of GAL in biological samples. This is the first study to identify the target tissues of GAL, and the results may help to elucidate the mechanisms underlying its therapeutic effects in vivo.