Advanced Materials Research Vols. 726-731

Abstract: The aim of this study is to analyze the properties of microspheres, which was obtained from an iron tailings. The flow-sheet of chemical method consists of chemical co-precipitation of Fe₃O₄ magnetic microspheres, SiO₂ packaged and amino silicon alkylation modification with anthrone under NaBH₄ existence. The results show that microspheres can be obtained successfully and it not only has a strong magnetism, but also has a fluorescence effort with the irradiating processing by ultraviolet with a wavelength of 282nm. This microsphere particle is a kind of high-value, environmentally-friendly products, it can be traced and served as a magnetic guide due to its magnetism and fluorescence properties, which has a big potential in medical technology and biological science.

Abstract: Field experimental results about methane (CH₄) emissions of rice growing seasons were analyzed in south Jiangsu province from 2001 to 2010. In order to study the temporal and spatial variation characteristics, conducting a database of CH₄ emissions of rice paddy field in the area. On the spatial distribution, Zhenjiang city had the highest CH₄ emission flux in rice growing season of this area, up to 7.80g/(m²h). Amount of CH₄ emissions per unit area in Changzhou city was slightly higher than other cities, up to 17.17g/m². From 2001 to 2010, both the rice growing area and the CH₄ emission of south Jiangsu province shown a declining trend during last decade. The rice growing area declined 170670 ha, a drop of 28.81%; total CH₄ emissions decreased by 29.90×10¹⁰g, a drop of 30.72%. From 2001 to 2010, there was no significant difference of CH₄ emissions per unit area between the cities, all CH₄ emissions reduction was mainly due to a reduction of rice growing area.

Abstract: In this paper, a mathematical model has been proposed, which consists of three variables: non-toxic phytoplankton (NTP), toxin producing phytoplankton (TPP) and zooplankton. In this model, an Monod- Haldane functional response is utilized to identify the grazing process of zooplankton due to the phytoplankton toxicity. The product of square of TPP density with square of NTP density is to depict the allelopathic influence on NTP. Numerical analysis indicates that the phytoplankton toxicity has a significant influence on the dynamical complexity and species biomass level through bifurcation diagrams. All these results are expected to be of significance in exploration of the dynamical complexity of ecosystems.

Abstract: In this paper, spatiotemporal dynamics of a phytoplankton-fish system with the Allee effect and harvest effect are investigated mathematically and numerically. Mathematical theoretical works have been pursued for the investigation of the stability of the equilibrium point of the phytoplankton-fish system with the Allee effect and harvest effect, which in turn provide a theoretical basic for the numerical simulation. Numerical analysis works indicate that Allee effect and harvest effect have a strong effect on the spatiotemporal dynamics of the phytoplankton-fish system using pattern formation. These results may help us to better understand phytoplankton-fish interactions.

Abstract: For two conditions of (non-) vegetation cover in uranium tailings beach face, the concentration distribution and settlement regularity of tailing sand with diameter of 10μm at speed of 0.5, 1, 2, and 4 m/s was studied by numerical simulation method. Results shows, with the increase of wind speed and migration distance, particle concentration decreases. Compared with the non-vegetation cover condition, particles concentration in the condition of with vegetation cover is significantly higher than the condition that without vegetation cover; but along with the increase of horizontal distance, the concentration lowers than the latter gradually.

Abstract: The success of a recirculating aquaculture system (RAS) greatly depends on the structure, dynamics and activities of microbial community. Heterotrophic bacteria as the major members play various roles. The heterotrophic bacterial community structure in threestaged biofilters was studied using four different media. 228 isolates belonging to 77species were obtained and affiliated to Gammaproteobacteria, Alphaproteobacteria, Bacteroidetes, Firmicutes, Actinobacteria and Betaproteobacteria. Gammaproteobacteria was the predominant group. The concurrence was found between potential pathogens (Vibrio and Shewanella) and probiotics (Bacillus and Pseudomonas). On the basis of community diversity index, we could infer that differences existed between stages, and the diversity index increased along the biofilters. A comprehensive understanding of microbial community in RAS will be in favor of utilization of microbial resources and optimizing the culture systems' operation.

Abstract: Improper exploitation of mine would lead to a series of geological disasters, such as surface subsidence, collapse, landslide, debris flow, water pollution, earthquake and etc., the results would endanger the safety of life and property, and caused serious economic losses to the state. As a case of Jiazhuang coal mining area of western of Shijiazhuang City based on the ecological problems, on the basis of PSR model, mine geological environment remediation basis, principles and objectives have been set. We puts forward a series of concrete measures of functional areas of governance for remediating of destruction problem of geological environment in western of Shijiazhuang coal mining area, taking comprehensive protection measures, soil formation, shelterbelt, slope shrub, wastewater, waste liquid emission in the mine production process must fit for standard of country. planting vegetation and the scarps leaved by mining reclamation or fill soil in the mine tailings, taking restoration of the original landform governance when constructed buildings and roads destroy the landform in field area.

Abstract: The experiment was conducted to select Pteris cretica ecergemiensis with fast growing and high enrichment of heavy metals among twenty plants and to evaluate its rule in accumulating Cu and Ni and the biological and biochemical functions using the solution culture method. The results showed that: (1) The Pteris cretica ecergemiensis had a good growth, and a high ability to accumulate the Cu and Ni with the interction effects of Cu and Ni. (2) With the increase of Cu and Ni concentration, the activities of SOD and CAT increased at first and then reduced, and the proline content increased. In conclusion, the Pteris cretica ecergemiensis is one of potential species for the great remediation of heavy metal pollution.

Abstract: An Investigation of the micelle aggregation number (N) and hydrodynamic diameter (D_h) is conducted on nonionic switchable surfactant 11-ferrocenylundecyl polyoxyethylene ether (FPEG), the micelle aggregation number of FPEG solution is determined by steady-state fluorescence probe, the results show that the micelle aggregation number (N) increase linearly with the concentration range from 5 to 12 times CMC of FPEG solutions. The critical micelle aggregation number N_m which means that the aggregation number of surfactant at the concentration of CMC is calculated to be 66. The hydrodynamic diameter (D_h) of FPEG micelle is determined by dynamic light scattering (DLS), the measurement angle is fixed at 90°and the wavelength is 532nm, the distribution data analyses by NNLS (non-negatively constrained least square) algorithm, the results reveal that the mean value of D_h at the concentration of 0.5 mmolL^-1 is 7.8nm. the POLY value, which used to explain the micelle polydispersity in the aqueous solution, is measured and the results show that the POLY values are slightly different, this indicates that the micelle aggregation morphology of FPEG is polydispersity in the aqueous solution.

Abstract: The current knowledge on the treatment of resorcinol-and nitrogen-containing wastewater in different treatment wetlands is limited. This study investigated three laboratory-scale treatment wetlands, namely, floating wetland, planted wetland and unplanted wetland, treating artificial wastewater containing resorcinol and ammonium. Under the inflow resorcinol concentration of 10 mg/L, these wetlands exhibited a removal efficiency of approximately 94% on average, with a specific area removal rate of 260 mg/(m²·d), regardless of wetland type and the presence of plants. These results suggest that treatment of resorcinol-containing wastewater by wetlands is a low-cost and ecological alternative. Compared with the dynamics of ammonium in the unplanted wetland, the high ammonium removal rate (>95%) observed for the planted and floating wetlands strongly indicated that the plants stimulated ammonium oxidation processes mainly by releasing oxygen from the roots. Acidification at pH 3, which can be attributed to an active nitrification process and the secretion of hydrogen ions by the plant roots, was observed in the floating wetland. The low pH buffer capacity could be caused by the low content of dissolved inorganic carbonates, and the use of substrate may act as a barrier to prevent rapid diffusion of carbon dioxide from the pore water to the atmosphere. The significant nitrate accumulation rate of 20 mg/L noted in the floating wetland indicated a limited denitrification process due to the high redox condition (600 mV). A better oxygenated condition for the floating wetland is beneficial to oxidation removal of organic compounds and ammonium, but it may not be good for such reduction processes as denitrification.