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1. Controllable synthesis of porous flower-shaped ZnO nanostructures and their morphology-dependent photocatalytic properties | |||
TIAN Minggang,JIA Xiaohua | |||
Environmental Science and Techology 29 March 2016 | |||
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Abstract:Porous flower-like zinc oxide (ZnO) nanostructures are prepared by annealing layered precursor of zinc hydroxide carbonate. The morphology and crystal structure of the porous flower-like ZnO nanostructures are characterized by field emission scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. During the investigation, the temperature dependence of particle sizes, crystal structures and morphology of ZnO nanostructures were analyzed from room temperature to 700 C. Structural transitions were also discussed. The effect of annealing temperature on the photocatalytic properties were investigated. As the annealing temperature increased, the photocatalytic properties show a general enhancing tendency. The porous flower-like ZnO with high photocatalytic properties are obtained by annealing the sample at 700 C for 2 h. In addition, the relationship between the photocatalytic properties and the microstructure of the as-prepared flower-like ZnO nanostructures is also investigated. | |||
TO cite this article:TIAN Minggang,JIA Xiaohua. Controllable synthesis of porous flower-shaped ZnO nanostructures and their morphology-dependent photocatalytic properties[OL].[29 March 2016] http://en.paper.edu.cn/en_releasepaper/content/4682469 |
2. A Hybrid LBM-FDM Model for Sediment Transport and Riverbed Deformation | |||
Haifei Liu,Yu Ding,Min Li,Ping Lin | |||
Environmental Science and Techology 17 December 2013 | |||
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Abstract:In this study, a two-dimensional hybrid numerical model for sediment transport based on lattice Boltzmann method and finite difference method is presented. The governing equations for water flow and suspended sediment transport are the shallow water equations and the advection-diffusion equations, respectively. Sediment load is also involved, so that riverbed deformation is numerically simulated. The model is verified by testing transportation of bank-slump sediment in a sharp bended channel with the comparison to the results of well-accepted finite volume method, illustrating the effectiveness of the proposed hybrid model. | |||
TO cite this article:Haifei Liu,Yu Ding,Min Li, et al. A Hybrid LBM-FDM Model for Sediment Transport and Riverbed Deformation[OL].[17 December 2013] http://en.paper.edu.cn/en_releasepaper/content/4576041 |
3. A LBM approach for wet-dry boundary treatment | |||
Haifei Liu,Yu Ding | |||
Environmental Science and Techology 08 November 2013 | |||
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Abstract:Based on the lattice Boltzmann scheme for 1D shallow water equations, this study presents an approach for the wet-dry boundary condition. In order to build up a relation between the dry bed cell and its neighboring wet cell, the Chapman-Enskog expansion and the Taylor expansion are used. This approach has several advantages: no spurious assumption of a thin water film, no nonphysical linear extrapolation of water depth or velocity, and no violation of local dependence. A typical test of long wave in a container with parabolic bed topography and bed friction is used to test the scheme. The numerical results agree well with the analytical solution, demonstrating the effectiveness and accuracy of the new approach. | |||
TO cite this article:Haifei Liu,Yu Ding. A LBM approach for wet-dry boundary treatment[OL].[ 8 November 2013] http://en.paper.edu.cn/en_releasepaper/content/4568392 |
4. Effects of humic acid on Zn2+ adsorption in drinking water distribution systems with amorphous Al(OH)3 formation | |||
Wang Wendong,Zhang Xiaoni,Zhou Lichuan,Ding Zhenzhen,Wang Xiaochang | |||
Environmental Science and Techology 07 January 2013 | |||
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Abstract:Zinc (Ⅱ) commonly exists in drinking water. This paper aims to investigate the effects of humic acid on the adsorption of Zn2+ on amorphous Al(OH)3. Both suspension and well scaled forms of Al(OH)3 were investigated applying ICP-AES determination and Visual MINTEQ calculation. It was found that in solutions without HA, pH had notable effects on the removal of Zn2+. Chemical adsorption mainly took place at pH above 7.5; 1.0 g solid could accumulate about 15.9 mg Zn2+ at 15℃. Because of H+ inhibition, active reaction sites on amorphous Al(OH)3 surface were much less at pH below 7.5. The adsorption of Zn2+ on Al(OH)3 changed gradually from chemical coordination to physical adsorption. Compared with Zn2+, the adsorption of HA on Al(OH)3 suspension was strong. In drinking water with HA coexisting, the adsorption of Zn2+ was enhanced notably; while pH had little effects its removal. Under the bridging effects of HA, Zn2+ could not be detected in solution with HA above 1.0 mg/L, much lower than the standard required level. The adsorption of Al(OH)3 scale for Zn2+ was weak, about 0.2 mg/g. Better management on sediment accumulation and Zn2+ preservation was suggested to control the concentration of Zn2+ residual. | |||
TO cite this article:Wang Wendong,Zhang Xiaoni,Zhou Lichuan, et al. Effects of humic acid on Zn2+ adsorption in drinking water distribution systems with amorphous Al(OH)3 formation[OL].[ 7 January 2013] http://en.paper.edu.cn/en_releasepaper/content/4511794 |
5. Adsorption of thallium(I) onto minerals and geological materials: Influence of pH and humic acid | |||
LIU Juan,LIPPOLD Holger,WANG Jin,LIPPMANN-PIPKE Johanna,CHEN Yongheng | |||
Environmental Science and Techology 15 September 2010 | |||
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Abstract:In this paper, the adsorption of the severely toxic heavy metal thallium (Tl) as a monovalent cation onto three representative materials (goethite, pyrolusite and a natural sediment sampled from a field site) was examined as a function of pH in the absence and presence of two natural humic acids (HAs) , using 204Tl(I) as a radiotracer. In order to obtain a basic understanding of the relative trends of the pH functions in the adsorption of Tl(I) with and without HA, adsorption of HAs and humate complexation of Tl(I) as a function of pH were investigated as well. In spite of the low complexation between Tl(I) and HAs, the presence of HAs results in obvious alterations of Tl(I) adsorption onto pyrolusite and sediment. An influence on Tl(I) adsorption onto goethite was not observed. Predictions of Kd (distribution coefficient) for Tl(I) on goethite in the presence of HAs based on a linear additive model agree well with the experimental data, while a notable disagreement occurs for the pyrolusite and sediment systems. Accordingly, it is suggested that HAs and goethite may act as a non-interacting adsorbent mixture under the conditions here, but more complex interactive effects may take place between the HAs and mineral phases of pyrolusite or sediment. | |||
TO cite this article:LIU Juan,LIPPOLD Holger,WANG Jin, et al. Adsorption of thallium(I) onto minerals and geological materials: Influence of pH and humic acid[OL].[15 September 2010] http://en.paper.edu.cn/en_releasepaper/content/4385379 |
6. The Relation between Algae and Fungi in the Water Body and the Formation Mechanism of Ocean Red Tides | |||
Pan Xianguang,Yu Zidong | |||
Environmental Science and Techology 18 May 2010 | |||
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Abstract:This paper has analyzed the opposite and united relations between algae and fungi in the water body from the micro perspective; they maintain the ecological balance of the water body. It has also analyzed the primary causes of the two major water quality disasters-fungi water quality disaster and algae water quality disaster, and theoretically analyzed the formation mechanisms of red tides and green tides of ocean. In the meantime, it has also analyzed the major cause of Qingdao green algae disaster. | |||
TO cite this article:Pan Xianguang,Yu Zidong. The Relation between Algae and Fungi in the Water Body and the Formation Mechanism of Ocean Red Tides[OL].[18 May 2010] http://en.paper.edu.cn/en_releasepaper/content/4372843 |
7. Coagulation performance and residual aluminum speciation of Al2(SO4)3 and polyaluminum chloride (PAC) in Yellow River water treatment | |||
Yang Zhonglian,Gao Baoyu,Yue Qinyan | |||
Environmental Science and Techology 08 April 2010 | |||
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Abstract:The effect of pH and coagulant dosage on the coagulation performance of Al2(SO4)3 and PAC with respect to the treatment of Yellow River water was investigated in this paper and the separation and measurement of residual aluminum speciation were also conducted. The results indicated that PAC showed superior coagulation performance compared to that of Al2(SO4)3 during the Yellow River water treatment. At a dosage of 15 mg/L, PAC achieved an optimum removal efficiency of turbidity, UV254 and DOC of 96.3%, 57.1%, 32.7%, respectively and Al2(SO4)3 also achieved an optimum removal efficiency of turbidity, UV254 and DOC of 94.5%, 53.5% 34.8%, respectively. For PAC and Al2 (SO4)3, the optimum pH during the treatment of Yellow River water could be determined at 6.0. Different residual aluminum speciation exhibited different trends with dosage and pH variation. For the two coagulants, no matter under different dosage or under different pH, the majority of residual total aluminum existed most in the form of total dissolved Al, among which, dissolved organically-bound Al was the predominant speciation. Dissolved inorganically-bound monomeric Al was the main component in dissolved monomeric Al. PAC showed lower concentration for the several kinds of residual aluminum species; except the dissolved organically-bound Al and PAC could effectively reduce the concentration of dissolved monomeric Al. | |||
TO cite this article:Yang Zhonglian,Gao Baoyu,Yue Qinyan. Coagulation performance and residual aluminum speciation of Al2(SO4)3 and polyaluminum chloride (PAC) in Yellow River water treatment[OL].[ 8 April 2010] http://en.paper.edu.cn/en_releasepaper/content/41721 |
8. A Coupled Lattice Boltzmann Model for Advection and Anisotropic Dispersion Problem in Shallow Water | |||
Yineng Li,Ping Huang | |||
Environmental Science and Techology 30 December 2008 | |||
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Abstract:A coupled lattice Boltzmann model(CLBM) for 2-D advection and anisotropic dis- persion equation(AADE) and shallow water equations is formulated and implemented. Multi-relaxation-time (MRT) method is used for the flow field and the L-basis two- relaxation-time (TRT) method is used for the pollutant field. The relaxation time for the antisymmetric part of the pollutant deviates from a constant for flows with variable free surface water depth. Numerical tests show that this scheme strictly obeys conserva- tion of mass and momentum. And the model has a better accuracy when zD is closer to 1/2 and ze is closer to sum(zd/9). Excellent agreement is obtained between numerical predictions and analytical solutions in pure dispersion problem and advection-dispersion problem. Comparison with finite different method indicates that the variation of the free surface water depth does not affect the mass and momentum conservation of the model and that the model has the ability to simulate complex bed topography problem. Comparison with finite volume method in the 2-D steady flow around a rectangular column with non-slip boundary shows that the LB scheme has the capacity to solve the complex advection- dispersion problems in shallow water. | |||
TO cite this article:Yineng Li,Ping Huang. A Coupled Lattice Boltzmann Model for Advection and Anisotropic Dispersion Problem in Shallow Water[OL].[30 December 2008] http://en.paper.edu.cn/en_releasepaper/content/27110 |
9. Root-Water/Nitrogen-Uptake and Root Nitrogen Mass of Winter Wheat under Optimal Water Condition | |||
Shi Jianchu ,Zuo Qiang | |||
Environmental Science and Techology 17 December 2007 | |||
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Abstract:Root water and nitrogen uptake are key processes for plant growth and soil water and nitrogen transport in the soil-plant system. Enormous effort has been made to set up the rational root-water-uptake (RWU) and root-nitrogen-uptake (RNU) models on the basis of root length to simulate soil water and nitrogen dynamics. However, the diversities of root uptake activity among different roots or different parts of a root, and the effect of soil nitrogen level on RWU were ignored. In this study, two greenhouse experiments with winter wheat seedlings cultured in nutrient solution (Exp. 1) and sand soil columns (Exp. 2) were conducted to investigate the relationship between root water/nitrogen uptake activity and root length, root nitrogen mass (RNM) of winter wheat under optimal water condition. Results showed that the potential RWU and RNU coefficients (per unit root length) changed sensitively with root age and soil nitrogen level. Nevertheless, when RNM was taken into consideration, RWU and RNU were found to be linearly correlated with RNM, and the potential RWU coefficient per unit RNM was almost a constant for both the whole root zone and different soil layers, independent of root age and soil nitrogen level but dependent linearly on the free water surface evaporation rate. The interrelations between RWU, RNU and RNM of winter wheat under optimal water condition would be helpful to set up rational RWU and RNU models for simulating soil water and nitrogen movement in the soil-wheat system. | |||
TO cite this article:Shi Jianchu ,Zuo Qiang . Root-Water/Nitrogen-Uptake and Root Nitrogen Mass of Winter Wheat under Optimal Water Condition[OL].[17 December 2007] http://en.paper.edu.cn/en_releasepaper/content/17058 |
10. Digital Change Detection by Post-Classification Comparison of RS Data in Land Use of Guangzhou | |||
Fenglei Fan,Wang Yunpeng,Qiu Maohui | |||
Environmental Science and Techology 17 April 2007 | |||
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Abstract:Remote sensing has long time been an important component of regional planning for applications ranging form urban fringe change detection to monitoring change detection of land use. On the other hand, the technologies and methods of change detection also have evolved dramatically during past 20 years. So it has been well recognized that the change detection had become the best methods for researching dynamic change of land use by multi-temporal remotely-sensed data.The purpose of this paper is to detect land use change surrounding the area of Guangzhou using TM image (Dec 22,1998) and ETM image (Jan. 10,2003). A county administrative boundary vector layer of the Pearl River Delta (2000) was used to get the subset image of Guangzhou. Unsupervised classification is performed by the K_Means method. At last, two-time subset images of Guangzhou are compared on a pixel-by-pixel basis using the post-classification comparison method and the “from-to” change matrix is produced, the land use change information obtained. | |||
TO cite this article:Fenglei Fan,Wang Yunpeng,Qiu Maohui. Digital Change Detection by Post-Classification Comparison of RS Data in Land Use of Guangzhou[OL].[17 April 2007] http://en.paper.edu.cn/en_releasepaper/content/12274 |
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