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EVALUATION OF THREE-DIMENSIONAL NUMERICAL MODEL FOR SALINE INTRUSION AND PURGING IN SEWAGE OUTFALLS

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Journal of Hydrodynamics 2007年第1期19卷 48-53页

作者： WU wei yan Zhong-min College of Water Conservancy and Hydropower Engineering Hohai University Nanjing 210098 China

Saline intrusion into sewage outfalls will greatly decrease the efficiency of the structures. The numerical model for this flow has been limited to one- and two-dimensional ones. In this article, a three-dimensional numerical model for saline intrusion and purging in sewage outfalls was developed. The flow was modeled in three dimensions under turbulent conditions with the RNG k-ε turbulence model. The numerical results provided quantitative evidence of the fundamental flow mechanisms that took place during saline intrusion and purging. The comparisons of the results with that of two-dimensional model and that of experiments indicate that the three-dimensional numerical model developed in this article is more effective in predicting the internal flow in outfalls.

关键词： saline intrusion sea ouffalls numericalsimulation three-dimensional numerical model

Arsenic mobilization from soils in the presence of herbicides

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Journal of Environmental Sciences 2019年第11期31卷 66-73页

作者： Yuxuan Jiang Wen Zhong wei yan Li yan Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China University of Chinese Academy of Sciences Beijing 100049 China

Arsenic (As) mobilization in soils is a fundamental step controlling its transport and fate,especially in the presence of the co-existing *** this study,the effect of two commonly used herbicides,glyphosate (PMG) and dicamba,and two competing ions including phosphate and humic acid,on As desorption and release was investigated using batch and column *** batch kinetics results showed that As desorption in the presence of competing factors conformed to the pseudo-second order kinetics at pH range of *** impact of phosphate on desorption was greatest,followed by *** competitive effect of dicamba and humic acid was at the same level with electrolyte *** situ flow cell ATR-FTIR analysis was performed to explore the mechanism of phosphate and PMG impact on As *** results showed that PMG promoted As (Ⅲ) desorption by competiting for available adsorption sites with no change in As(Ⅲ) complexing *** the other hand,phophate changed As(Ⅲ) surface complexes from bidentate to monodentate structures,exhibiting the most siginficant effect on As(Ⅲ) ***(Ⅴ) surface complexes remained unchanged in the presence of PMG and phosphate,implying that the competitive effect for As(Ⅴ) desorption was primarily determined by the available adsorption ***-term (10 days) soil column experiments suggested that the effect of humic acid on As mobilization became pronounced from 3 days (18 PVs).The insights of this study help us understand the transport and fate of As due to herbicides application.

关键词： Arsenic desorption Herbicides Competing ions In situ ATR-FTIR Long-term column transport

Tunability of Band Gaps of Programmable Hard-Magnetic Soft Material Phononic Crystals

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Acta Mechanica Solida Sinica 2022年第5期35卷 719-732页

作者： Bo Li wei yan Yuanwen Gao Department of Mechanics and Engineering Science College of Civil Engineering and MechanicsLanzhou UniversityLanzhou730000China Key Laboratory of Mechanics On Environment and Disaster in Western China The Ministry of Education of ChinaLanzhou UniversityLanzhou730000China

In this paper,the elastic wave band gap characteristics of two-dimensional hard-magnetic soft material phononic crystals(HmSM-PnCs)under the applied magnetic field are ***,the relevant material parameters of hard-magnetic soft materials(HmSMs)are obtained by the experimental *** the finite element model of the programmable HmSM-PnCs is established to calculate its band structure under the applied magnetic *** effects of some factors such as magnetic field,structure thickness,structure porosity,and magnetic anisotropy encoding mode on the band gap are *** results show that the start and stop frequencies and band gap width can be tunable by changing the magnetic *** magnetic anisotropy encoding mode has a remarkable effect on the number of band gaps and the critical magnetic field of band *** addition,the effect of geometric size on PnC structure is also *** the increase of the structure thickness,the start and stop frequencies of the band gap increase.

关键词： Phononic crystal Hard-magnetic soft materials Magnetic field Magnetic anisotropy encoding modes Structure thickness Band gap

Microblogging Reposting Mechanism: An Information Adoption Perspective

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Tsinghua Science and Technology 2014年第5期19卷 531-542页

作者： wei yan Jinghua Huang School of Economics and Management Tsinghua University

This study uses the Elaboration Likelihood Model （ELM） and social presence theory to examine the microblogging reposting mechanism. Subjective and objective data were collected from 216 respondents in a field experiment. The results indicate that information quality and source credibility of microblogging messages affect users＇ reposting intention by affecting their perceptions of the usefulness and enjoyment of the information. Perceived enjoyment has a greater impact on reposting intention than perceived usefulness. Furthermore, users are able to perceive social presence when interacting with microblogging messages. Social presence plays a full mediating role between information quality and perceived enjoyment, and a partial mediating role between information quality and perceived usefulness.

关键词： microblogging reposting information adoption elaboration likelihood model social presence field experiment

A POSTERIORI ERROR ESTIMATE FOR BOUNDARY CONTROL PROBLEMS GOVERNED BY THE PARABOLIC PARTIAL DIFFERENTIAL EQUATIONS

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Journal of Computational Mathematics 2009年第1期27卷 68-88页

作者： wei Gong Ningning yan LSEC Institute of Systems Science Academy of Mathematics and Systems Science Chinese Academy of Sciences Beijing 100190 China

In this paper, we discuss the a posteriori error estimate of the finite element approximation for the boundary control problems governed by the parabolic partial differential equations. Three different a posteriori error estimators are provided for the parabolic boundary control problems with the observations of the distributed state, the boundary state and the final state. It is proven that these estimators are reliable bounds of the finite element approximation errors, which can be used as the indicators of the mesh refinement in adaptive finite element methods.

关键词： Boundary control problems Finite element method A posteriori error estimate Parabolic partial differential equations.

Reverse-time type nonlocal Sasa–Satsuma equation and its soliton solutions

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Communications in Theoretical Physics 2023年第7期75卷 48-57页

作者： Xue-wei yan Yong Chen School of Mathematics Harbin Institute of TechnologyHarbin150001China

In this work,we study the Riemann–Hilbert problem and the soliton solutions for a nonlocal Sasa–Satsuma equation with reverse-time type,which is deduced from a reduction of the coupled Sasa–Satsuma *** the coupled Sasa–Satsuma system can describe the dynamic behaviors of two ultrashort pulse envelopes in birefringent fiber,our equation presented here has great physical *** classification of soliton solutions is studied in this nonlocal model by considering an inverse scattering transform to the Riemann–Hilbert ***,we find that the symmetry relations of discrete data in the special nonlocal model are very ***,the eigenvectors in the scattering data are determined by the number and location of ***,multi-soliton solutions are not a simple nonlinear superposition of multiple *** exhibit some novel dynamics of solitons,including meandering and sudden position ***,they have the bound state of multi-soliton entanglement and its interaction with solitons.

关键词： nonlocal Sasa-Satsuma equation Riemann-Hilbert problem soliton solution

Comparison and integration of final electromagnetic stirring and thermal soft reduction on continuous casting billet

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Journal of Iron and Steel Research International 2021年第2期28卷 160-167页

作者： yan-shen Han wei yan Jiang-shan Zhang Jun Chen wei-qing Chen Qing Liu State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Xiangtan Iron&Steel Co. Ltd.of Hunan ValinXiangtan 411101HunanChina

Final electromagnetic stirring(F-EMS)and thermal soft reduction(TSR)are techniques that improve the inner quality of continuous casting billets,but they have rarely been applied *** application effects of F-EMS and TSR were compared,and a process integrating F-EMS and TSR was adopted for a billet continuous caster.A heat transfer model was established to calculate the thermal behavior of 82A tire cord steel *** locations of F-EMS and TSR were determined,followed by conducting a series of plant trials,involving F-EMS alone,TSR alone,and the integrated process of F-EMS and *** results showed that F-EMS or TSR could effectively improve the inner quality of the billet under their respective suitable working ***,F-EMS was found to be more helpful in terms of improving central segregation,while TSR tended to improve V-segregation,central porosity,and *** integration of F-EMS and TSR allowed the advantages of each technique to be utilized,thereby better improving the inner *** all the working conditions,82A steel billet showed optimum inner quality when the current of F-EMS was 240 A and the cooling intensity of TSR was 2.2 m^(3) h^(−1).These findings demonstrate that the integration of F-EMS and TSR is promising for application on continuous casting billets.

关键词： Billet continuous casting Final electromagnetic stirring Thermal soft reduction Central segregation Inner quality

Asenic removal from groundwater using granular chitosan-titanium adsorbent

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Journal of Environmental Sciences 2022年第2期34卷 202-209页

作者： Zuben Xu Yaqin Yu Li yan wei yan Chuanyong Jing State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China School of Environmental Science and Engineering Shandong UniversityQingdao 266237China

Arsenic(As)contamination poses an urgent environmental risk,and its removal from groundwater remains a challenge due to the lack of efficient ***,a novel granular chitosan-titanium(CS-Ti)adsorbent was fabricated by the sol-gel *** experiments show that As(V)adsorption on CS-Ti followed the pseudo-second-order kinetic model,and the adsorption isotherm conformed to the Freundlich model with the correlation coefficient of *** situ FTIR spectra revealed that the CS-Ti adsorbent was composed of amorphous TiO_(x) and chitosan by forming C-O-Ti and N-Ti bonds,and the amorphous TiO_(x) was responsible for As(V)*** small-scale column tests show that 165.6μg/L of As in groundwater were effectively removed in approximately 126-bed volumes,and the spent adsorbents were regenerated with 0.01 mol/L Na OH and maintained the adsorption efficiency after four *** study provides a simple and practical route to fabricate adsorbents for water treatment.

关键词： Arsenic Chitosan Titanium Groundwater Adsorption

Experimental and molecular dynamic simulation study of perfluorooctane sulfonate adsorption on soil and sediment components

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Journal of Environmental Sciences 2015年第3期27卷 131-138页

作者： Ruiming Zhang wei yan Chuanyong Jing State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental SciencesChinese Academy of Sciences

Soil and sediment play a crucial role in the fate and transport of perfiuorooctane sulfonate （PFOS） in the environment. However, the molecular mechanisms of major soil/sediment components on PFOS adsorption remain unclear. This study experimentally isolated three major components in soil/sediment： humin/kerogen, humic/fulvic acid （HA/FA）, and inorganic component after removing organics, and explored their contributions to PFOS adsorption using batch adsorption experiments and molecular dynamic simulations. The results suggest that the humin/kerogen component dominated the PFOS adsorption due to its aliphatic features where hydrophobic effect and phase transfer are the primary adsorption mechanism. Compared with the humin/kerogen, the HA/FA component contributed less to the PFOS adsorption because of its hydrophilic and polar characteristics. The electrostatic repulsion between the polar groups of HA/FA and PFOS anions was attributable to the reduced PFOS adsorption. When the soil organic matter was extracted, the inorganic component also plays a non-negligible role because PFOS molecules might form surface complexes on SiO2 surface. The findings obtained in this study illustrate the contribution of organic matters in soils and sediments to PFOS adsorption and provided new perspective to understanding the adsorption process of PFOS on micro-interface in the environment.

关键词： Humic/fulvic acid Humin/kerogen PFOS Adsorption Molecular dynamics