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Pang J.-S.,Xinhui Entry Exit Inspection and Quarantine Bureau | Zhang H.-Y.,Guangdong University of Technology | Wu Q.-G.,Guangdong University of Technology | Lin J.,Guangdong University of Technology | And 2 more authors.
Cailiao Gongcheng/Journal of Materials Engineering | Year: 2011

Carbon-encapsulated copper nanoparticles were synthesized by carbon arc discharge technology, carbon-encapsulated copper-water nanofluid was prepared by two different method, chemical treatment with H2O2 and adding SDBS dispersant respectively. The effect of dispersion method on thermal transport of nanofluid was studied. The test indicated that the nanofluid prepared by chemical treatment to carbon-encapsulated copper nano-particle had higher thermal conductivity than that prepared by adding SDBS dispersant. There was a 60% enhancement in thermal conductivity with 2.0%(mass fraction) carbon-encapsulated copper loading using chemical treatment preparation method. Source


Pang J.,Xinhui Entry Exit Inspection and Quarantine Bureau | Zhang H.,Guangdong University of Technology | Li L.,Xinhui Entry Exit Inspection and Quarantine Bureau
Advanced Materials Research | Year: 2011

Carbon-encapsulated copper nanoparticles were synthesized by a carbon arc discharge method. The particles were characterized in detail by transmission electron microscope, high-resolution transmission electron microscopy, thermogravimetric and differential scanning calorimetry. The result showed that the outside graphitic carbon layers effectively prevented unwanted oxidation of the copper inside. The dispersion behaviors and thermal conductivity of Carbon-encapsulated copper nanoparticles in water with different dispersants were investigated under different pH values. The results showed that the dispersion and thermal conductivity enhancements of Carbon-encapsulated copper nanoparticles nanofluids are higher than that of copper nanoparticles. © (2011) Trans Tech Publications, Switzerland. Source


Pang J.-S.,Xinhui Entry Exit Inspection and Quarantine Bureau | Deng A.-H.,Xinhui Entry Exit Inspection and Quarantine Bureau | Mao L.-B.,Guangdong University of Technology | Peng X.-J.,Xinhui Entry Exit Inspection and Quarantine Bureau | Zhu J.,Xinhui Entry Exit Inspection and Quarantine Bureau
Xinxing Tan Cailiao/New Carbon Materials | Year: 2013

Carbon-coated iron nanoparticles were synthesized by a carbon arc discharge method using electrodes made of iron and graphite powder. The amorphous carbon layer of the carbon-coated iron nanoparticles was treated by a 30% H2O2 aqueous solution. Adsorption of the carbon-coated iron particles for heavy metal ions, such as Cr, Ni, Cd, Pb, Co and Mn, was studied. Results showed that carboxyl and hydroxyl groups were formed on the surface of the amorphous carbon layer after the treatment by hydrogen peroxide. In a strong alkaline medium, the hydroxyl and carboxyl groups increased the electrostatic attraction, and the adsorption performance of the treated carbon-coated iron particles for heavy metal ions was improved. The removal efficiencies for Cr, Ni, Cd, Pb, Co and Mn by the treated carbon-coated iron nanoparticles were all over 90% in a pH range of 8-10 and their adsorption capacity is much higher than that of activated carbons. Source


Pang J.,Xinhui Entry Exit Inspection and Quarantine Bureau | Deng A.,Xinhui Entry Exit Inspection and Quarantine Bureau | Mao L.,Guangdong University of Technology | Chen J.,China University of Technology | And 2 more authors.
Advanced Materials Research | Year: 2012

Magnetic carbon-coated iron nanoparitcles were employed as adsorbent to study the adsorption characteristics of some metal ions, such as Cr, Ni, Cu, Pb, Zn. The effect of solution conditions such as pH, amounts of adsorbent, the co-existent ions was investigated. The results show that adsorption property of carbon-coated iron particles to heavy metal ions is improved at the condition of treated by H 2O 2, and at pH 8-9.5, Cr, Ni, Cu, Pb and Zn were retained on 30mg carbon-coated iron nanoparticles after shaking 3 min, and could be eluted by acid solutions(pH=1∼2). © (2012) Trans Tech Publications, Switzerland. Source


Peng X.,Xinhui Entry Exit Inspection and Quarantine Bureau | Pang J.,Xinhui Entry Exit Inspection and Quarantine Bureau | Deng A.,Xinhui Entry Exit Inspection and Quarantine Bureau
Chinese Journal of Chromatography (Se Pu) | Year: 2011

A novel method for the simultaneous determination of seven phenoxyacid herbicides such as dicamba, fluroxypyr, 4-chlorophenoxyacetic acid (4-CPA), 2-methyl-4-chlorophenoxyacetic acid (MCPA), 2,4-dichlorophenoxyacetic acid (2,4-D), 2,4-dichlorophenoxybutyric acid (2,4-DB) and 4-(2-methyl-4-chlorophenoxy)butyric acid (MCPB) in environmental water by three phase hollow fiber liquid phase microextraction (HF-LPME) coupled with high performance liquid chromatography (HPLC) was developed. In order to optimize the experimental conditions, the orthogonal test has been used. The effects of extraction solvent, pH of the donor phase and acceptor phase, extraction time, stirring speed and salt concentration on the detection were investigated. The optimal experimental conditions were as follows: octanol as organic solvent, pH 3 of donor phase, pH 12 of acceptor phase, extraction time of 30 min, stirring speed of 400 r/min. The results showed that the proposed method provided a wide linear range for 7 phenoxyacid herbicides with correlation coefficients of 0.9953-0.9988. The detection limits ranged from 0.2 to 1.0 μg/L. The enrichment factors were in the range of 76.7-121. The recoveries were in the range of 68%-104% and the relative standard deviations (RSDs) were less than 8.1% for the environmental water samples. The method has the advantages of sensitivity, simplicity, fastness and the use of very small amounts of organic solvent. The method can meet the requirements of the determination of trace phenoxyacid herbicides in the environmental water samples, and the study provided a useful method for the analysis of trace substances in water samples. Source

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