Zhan X.,Zhejiang University |
Bao Y.,Zhejiang University |
Huang Z.,Zhejiang University |
Wang S.,Juhua Group Corporation
Gaofenzi Cailiao Kexue Yu Gongcheng/Polymeric Materials Science and Engineering | Year: 2011
It is difficult to determine the mean molecular weight (M w̄) and molecular weight distribution (MWD) of ethylene/tetrafluoroethylene copolymers (ETFE) by gel permeation in chromatography(GPC) method since ETFE can hardly be dissolved in the common solvents. The dynamic rheological method was applied to measure the M w̄ and MWD of ETFE, and the treatment method proposed by Tuminello was modified. The measured complex viscosity~frequency (ω) results were fitted by using Carreau-Yasuda equation to obtain the zero shear viscosity, which was further used to calculate the mass average molecular weight of ETFE. The generalized Maxwell model was applied in fitting the relationships between dynamic modulus (G′ and G″) and ω, to obtain the plateau modulus (G N 0), and the parameter k 2 in the equation of τ=1/ω=K 2M w 3.4 was deduced as K 2=12/π 2× K 1/G N 0 through the viscoelastic theory. MWD calculated from the dynamic modulus-ω relationship was narrow due to the limited range of ω, and the deviation was existed between the M w̄ determined by the complex viscosity-ω and dynamic modulus-ω relationships.
Li D.,Beijing University of Chemical Technology |
Zou G.,Beijing University of Chemical Technology |
Zheng G.,Juhua Group Corporation |
Yong X.,Beijing University of Chemical Technology
Cailiao Yanjiu Xuebao/Chinese Journal of Materials Research | Year: 2012
The changes of surface layer mechanical properties for duplex stainless steel and austenitic stainless steel after cavitaion corrosion were investigated by nano-indentation, and the relationship of surface layer mechanical properties with cumulative mass loss and microscopic corrosion morphologies was further investigated by weight loss and SEM. The results show that there are obvious effects of the microstructures on the changes of surface layer mechanical properties with displacement. Although stainless steels with different microstructures have different corrosion morphologies after cavitation corrosion, there is a same threshold for the degradation of surface layer mechanical properties, below which stainless steels were heavily subjected to cavitation corrosion and the microscopic morphologies of their corroded surfaces change markedly. This threshold is not related with the microstructures of stainless steels. © right.
Shen D.-S.,Zhejiang GongShang University |
Shen D.-S.,Zhejiang Provincial Key Laboratory of Solid Waste Treatment and Recycling |
Huang B.-C.,Zhejiang GongShang University |
Liu P.-Q.,China SINOMACH Heavy Industry Corporation |
And 3 more authors.
Journal of Chemistry | Year: 2013
A decentralized sewage treatment reactor was designed to treat wastewater in rural areas. To examine the factors influencing nitrogen removal, experiments were carried out at three levels of hydraulic surface load, three sludge concentrations, and three environment temperatures at low dissolved oxygen concentrations. The rate of denitrification decreased, and the rate of nitrification increased as the surface load rose. The maximum denitrification rate was 20.01 ± 3.02 g/(m 3·d) at a surface load of 1.11 ± 0.13 m 3/(m 2·h). The total nitrogen (TN) removal, efficiency initially increased and then decreased as the sludge concentration rose. When the sludge concentration increased to 3.5 ± 0.3 g/L, the system showed a good level of TN removal and a denitrification rate of 28.58 ± 1.22 g/(m 3·d) was achieved. Low temperature had a negative effect on the removal and transformation of nitrogenous pollutants. © 2013 Dong-Sheng Shen et al.
Juhua Group Corporation | Date: 2009-05-05
Chemicals used in industry, science, and photography film processing; chemicals used in agriculture; chemicals used in horticulture and forestry except fungicides, herbicides, insecticides and parasiticides; chemical reagent for non-medical purposes and chemical articles, namely, chemical fertilizers; artificial resins, unprocessed; plastics substances, unprocessed; manure for agriculture; chemical substances for preserving foodstuffs; antranilic acid; adhesives for industrial purposes.
Shen D.-S.,Zhejiang GongShang University |
Shen D.-S.,Zhejiang University |
Zheng Y.-G.,Hydrochina Huadong Engineering Corporation |
Yao J.,Zhejiang University |
And 4 more authors.
Huanjing Kexue/Environmental Science | Year: 2011
Pollutants characteristics, especially in components and contents of heavy metals and PCDD/Fs, were chemical analyzed and toxicological evaluated in fly ash from 6 typical kinds of solid waste incinerators in Zhejiang province. The results indicated that the main elements in fly ash were Si, Ca, Al, Fe, K, Na and Cl. Among all kinds of heavy metals, the Zn content was the highest one, whose average was up to 9 458 mg/kg. Meanwhile, the Cd, Zn, Cu, Cr, Ni, Pb and As contents in the fly ash samples were 642, 127, 22, 18, 15, 10 and 2-fold of those in polluted soil, respectively. The leaching ratios of heavy metals in fly ash concluded according to the HJ/T 299-2007 Procedure were lower than its limitation. However, the leaching ratios from NB and LS sample concluded according to the Toxicity Characteristic Leaching Procedure (TCLP) exceeded its limitation. The TEQ of PCDD/Fs from all samples were lower than the limitation in GB 5085.6-2007, while higher than the soil-limitation in Canadian, New Zealand and Sweden, with 105, 59, 401, 369 and 5-fold in the sample HZ, WZ, NB, TZ and HUZ, respectively. It could be concluded that the components and contents of the pollutants were various from different fly ashes. The components of heavy metals were mainly affected by the type of solid wastes. And the technology of the incinerator played important role in the pollution characteristics in fly ash. Thus, it is of significant meaning to study the particulate pollution characteristics of a certain fly ash before disposal or reuse for the purpose of adequate risk assessment and management.