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Liu Y.,Tianjin Normal University | Hu J.,Beijing Guodian Futong Science and Technology Development Co. | Li Y.,Nankai University | Wei H.-P.,Tianjin Normal University | And 4 more authors.
Talanta | Year: 2015

Carbon dots capped with polyethyleneimine (CD-PEI) were synthesized and applied in selective separation and preconcentration of trace Cr(VI). Dispersed particle extraction (DPE) slurry sampling with flame atomic absorption spectrometry (FAAS) was used to selectively and sensitively determine Cr(VI) in water samples. The as-synthesized CD-PEI was confirmed by Fourier transform infrared spectroscopy, high-resolution transmission electron microscopy, elemental analysis, fluorescence and zeta potential measurement. The adsorption of Cr(VI) on CD-PEI was evaluated. Its isothermal adsorption was studied and fitted in the Langmuir model. Nearly 85% of Cr(VI) was adsorbed within 10 min showed that the CD-PEI exhibited fairly fast kinetics for the sorption of Cr(VI). Experimental conditions, including the content and size of CD-PEI, sample pH, adsorption time, sample volume, slurry volume and interfering ions, were further optimized to obtain efficient preconcentration and high-precision determination of Cr(VI). CD-PEI with small size turned to be a good candidate for the preparation of slurry. CD-PEI served not only as a promising adsorbent for separation and preconcentration of Cr, but also a signal-enhancing agent in FAAS. The method achieved an enhancement factor of 30 and a detection limit (S/N=3) of 0.21 μg L-1 Cr(VI) with a consumption of 14.0 mL sample and an adsorption time of 5 min, which provided two times of signal enhancement. The RSD for 11 replicate measurements of 5.0 μg L-1 Cr(VI) was 2.8%. The possible signal enhancement mechanism was proposed. The developed method has been applied to determine trace Cr(VI) in a variety of water samples. © 2014 Elsevier B.V. All rights reserved. Source

Diao S.,Key Laboratory of Special Functional Aggregated Materials | Diao S.,Shandong University | Zhang S.,Key Laboratory of Special Functional Aggregated Materials | Zhang S.,Shandong University | And 8 more authors.
Journal of Applied Polymer Science | Year: 2011

Two kinds of treated fumed silica were prepared by treatment with either tetraphenylphenyltriethoxysilane (TPHTS) or both tetraphenylphenyltriethoxysilane and hexamethyldisilazane (TPHMTS), and were used as reinforcing filler for silicone rubber. The resistance to irradiation of the silicone rubber obtained was investigated by gamma ray of dose 500 kGy in air. The mechanical properties and the average molecular weight between crosslinking points (Mc) of the silicone rubber were determined before and after irradiation. The results show that the fumed silica treated by tetraphenylphenyltriethoxysilane (TPHPHS) can effectively improve the radiation resistance of silicone rubber while the fumed silica treated by both tetraphenylphenyltriethoxysilane and hexamethyldisilazane (MMN) cannot only effectively improve the radiation resistance of silicone rubber but also has excellent reinforcing effect on silicone rubber. © 2010 Wiley Periodicals, Inc. Source

Liu Y.,Tianjin Normal University | Li X.-S.,Tianjin Normal University | Hu J.,Beijing Guodian Futong Science and Technology Development Co. | Guo M.,Nankai University | And 4 more authors.
Colloids and Surfaces B: Biointerfaces | Year: 2015

A novel nanoparticle with multilayer core-shell architecture for cell imaging is designed and synthesized by coating a fluorescent YVO4:Eu core with a diblock copolymer, MPEG-b-PMAA. The synthesis of YVO4:Eu core, which further makes MPEG-b-PMAA-YVO4:Eu NPs adapt for cell imaging, is guided by the model determined upon the evaluation of pH and CEu%. The PMAA block attached tightly on the YVO4:Eu core forms the inner shell and the MPEG block forms the biocompatible outermost shell. Factors including reaction time, reaction temperature, CEu% and pH are optimized for the preparation of the YVO4:Eu NPs. A precise defined model is established according to analyzing the coefficients of pH and CEu% during the synthesis. The MPEG-b-PMAA-YVO4:Eu NPs, with an average diameter of 24nm, have a tetragonal structure and demonstrate luminescence in the red region, which lies in a biological window (optical imaging). Significant enhancement in luminescence intensity by MPEG-b-PMAA-YVO4:Eu NPs formation is observed. The capping copolymer MPEG-b-PMAA improves the dispersibility of hydrophobic YVO4:Eu NPs in water, making the NPs stable under different conditions. In addition, the biocompatibility MPEG layer reduces the cytotoxicity of the nanoparticles effectively. 95% cell viability can be achieved at the NPs concentration of 800mgL-1 after 24h of culture. Cellular uptake of the MPEG-b-PMAA-YVO4:Eu NPs is evaluated by cell imaging assay, indicating that the NPs can be taken up rapidly and largely by cancerous or non-cancerous cells through an endocytosis mechanism. © 2015 Elsevier B.V. Source

Wang Y.D.,Beijing Guodian Futong Science and Technology Development Co.
Computer, Intelligent Computing and Education Technology - Selected Peer Reviewed Papers From 2014 International Conference on Computer, Intelligent Computing and Education Technology, CICET 2014 | Year: 2014

By introducing the working theory of steel belt conveyor, the causes for wear condition of parts of scraper blade, chain and guide roller of running steel belt conveyor have been analyzed. Find out the optimization measure with minimum abrasion loss by corresponding optimization calculation. And through the application demonstration in a some power plant, by implementing the measures for treatment, the equipment defect could be reduced, and the operational reliability of the system could be improved. © 2014 Taylor & Francis Group, London, UK. Source

Wei S.J.,Changchun University of Technology | He L.,Henan University of Science and Technology | Xin W.,Beijing Guodian Futong Science and Technology Development Co. | Miao G.,Changchun University of Technology
Applied Mechanics and Materials | Year: 2013

In this paper, the relation between angle of rotation function of the five-bar and similar four-bar mechanisms' rigid-body and Coupler Rotation-Angle function is discussed. The principles of reduce the numerical atlas are proposed. A numerical atlas database comprising 240498 basic dimensional types is set up. Make the five-bar and similar four-bar mechanism for Rigid-Body Guidance with prescribed timing possible. Finally, an example is given to prove it. © 2013 Trans Tech Publications Ltd, Switzerland. Source

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