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Wei M.,Ningbo University | Ma L.,Ningbo Branch of Academy of Ordnance Science | Hu Y.-H.,Ningbo University | Zheng Z.-Z.,Ningbo University | Qiu Q.-F.,Ningbo University
Chinese Journal of Ecology | Year: 2015

Production of methane from paddy fields and the related archaeal community are both influenced by environmental factors and soil characteristics of the field (e.g. pH, carbon and nitrogen contents). To study the effect of soil pH on methane production and community structure of the methanogenic archaea at high temperature, two soil samples S1 (pH 7.88) and S2 (pH 4.67) developed from different matrices were anaerobically incubated at 50 °C for 100 days. Methane production was measured continually by gas chromatography during the incubation. Soil characteristics, such as pH, organic carbon and ammonium nitrogen contents were also evaluated in the supernatant or the soil itself. The variations in the microbial structure with incubation time in the two soils were studied by terminal restriction fragment length polymorphism (T-RFLP) analysis based on archaeal 16S ribosomal RNA gene. The results showed that the organic carbon content decreased with the formation of methane during incubation, whereas the variation of ammonium was similar in both the supernatants and soil samples S1 and S2. Although the final amount of methane produced was same for S1 and S2, the changes in pH and methane production rates were significantly different between the two soils. It was found that the rate of methane formation increased with the increase of pH. The T-RFLP profiles showed that Methanosarcinaceae and Methanocellaceae were the primary active methanogenic groups in paddy soil at 50 ˚C. Analysis of the entire T-RFLP profiles via two-dimensional plots of PCA (principal component analysis) revealed that the developmental direction of structures of the archaeal populations in the two soils were different. Acidic paddy soil was more suitable for enhancing the activity of Methanocellaceae. © 2015, editorial Board of Chinese Journal of Ecology. All rights reserved. Source

Wang Z.-F.,Ningbo Branch of Academy of Ordnance Science | Wang J.-Z.,Ningbo Branch of Academy of Ordnance Science | Cao J.-P.,Xian Modern Chemistry Research Institute | Zhang Y.-H.,Zhejiang University
Guti Huojian Jishu/Journal of Solid Rocket Technology | Year: 2013

Synthetic methods and technical route of polyaryloxyphosphazene were described in the paper, with a focus on research status of polyaryloxyphosphazene application in insulation coating material field. The study shows that polyaryloxyphosphazene possesses excellent characteristics such as high oxygen index, high thermal decomposition temperature, anti-NG migration and high charring rate et al, which has great application potential in solid rocket motor insulation and coating fields. Engineering technology of polyaryloxyphosphazene preparation is the main reason of limiting its promotion and applications currently. Some recommendations for the next step research work were put forward. Source

Wang J.-Z.,Ningbo Branch of Academy of Ordnance Science | Wang Z.-F.,Ningbo Branch of Academy of Ordnance Science | Cao J.-P.,Xian Modern Chemistry Research Institute
Guti Huojian Jishu/Journal of Solid Rocket Technology | Year: 2015

Aiming at the performance requirements of thermal insulation material for solid rocket motor, Poly(aryloxyphosphazene)based thermal insulation coating materials were prepared. Performances of the Poly(aryloxyphosphazene)thermal insulation coating materials, such as thermal conductivity, linear expansion coefficient, density, linear ablation rate and compatibility with propellant were characterized by using thermal conductivity measuring device, dynamic thermal analysis, SEM and the measuiring methods regulated by military standard. The results show that, the thermal conductivity of polyaryloxyphosphazene is 0.187 W/(m·K), the linear expansion coefficient is 2.31×10-4℃-1, the density is 1.196 g/cm3, the linear ablation rate is 0.109 mm/s, and the layer is hard with high char yield after ablation. The materials present good compatibility with propellant. The poly(aryloxyphosphazene)can be used as thermal insulation coating material for new advanced rocket engines due to its excellent physical properties and anti-erosion ability. ©, 2015, Journal of Solid Rocket Technology. All right reserved. Source

Wang Z.-F.,Ningbo Branch of Academy of Ordnance Science | Cao J.-P.,Xian Modern Chemistry Research Institute | Yao N.,Xian Modern Chemistry Research Institute | Wang J.-Z.,Ningbo Branch of Academy of Ordnance Science
Huozhayao Xuebao/Chinese Journal of Explosives and Propellants | Year: 2010

Polyaryloxyphosphazene was obtained with aryloxy substituting chlorine atom of the linear polydichlorophosphazene, which was synthesized by solution polymerization of hexachlorocyclotriphosphazene. The polymer was characterized by IR spectrum and analyzed by GPC, DMA, TGA, and thermal conductivity. The results show that the polymer obtained is polyaryloxyphosphazene with number-average molecular weight ranging from 38 343 to 44 625 and dispersion degree ranging from 3. 0305 to 4. 885 7. The peak temperature of the initial thermal decomposition is 374. 23°C and of main decomposition reaction is 397. 78°C. The weight of the polymer which shows obvious weight loss at the temperature of 461. 14°C and 529. 95°C could remain 45. 40% at the temperature of 565. 37°C and then keep constant. It can be expected that the polymer has good thermal stability at high temperature. The glass transition temperature of the polymer is -24. 09°C and the thermal conductivity 0.21 W/(m·K). Source

Wang Z.F.,Ningbo Branch of Academy of Ordnance Science | Zhang Y.H.,Zhejiang University | Mao J.,Zhejiang University | Wang J.Z.,Ningbo Branch of Academy of Ordnance Science
Advanced Materials Research | Year: 2013

Hydrothermal method was used to prepare Ce doped ZnO. Effects of doping ratio, reaction time, reaction temperature, filling degree on the flower-like morphology of ZnO were studied. And the phase, morphology and size of the products were characterized by XRD and SEM. The vector network analyzer was used to characterize the products electromagnetic performance. The results show that, Ce is successfully doped into the lattice of ZnO. The products maintain perfect flower-like structure when Ce:ZnO (molar ratio) is 0.5%. However, the flower-like morphology is damaged more and more obviously with the doped concentration increasing. The crystal growth rate accelerates with reaction temperature increasing. Microwave absorbing properties of ZnO can be improved greatly by doping Ce. The reflection loss is more than 10dB when the frequency between 9.8 GHz and 11.6GHz. © (2014) Trans Tech Publications, Switzerland. Source

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