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Journal of Environmental Sciences 2019年第2期31卷 217-226页

作者： Lei Wang Guodong Ji Siqiao Huang Key Laboratory of Water and sediment Sciences Ministry of EducationDepartment of Environmental EngineeringPeking University

Dibenzothiophene(DBT) degradation mechanisms and the transformation of pathways during the incubation of three types of coastal sediments with C/N ratios ranging from 1 to 9 were investigated. The DBT degradation efficiencies were clearly improved with increasing C/N ratio in reed wetland sediments, tidal wetlands sediments and estuary wetland sediments. The quantitative response relationships between DBT degradation rates and related functional genes demonstrate that the Kodama pathway-related gene groups were dominant factors at low C/N ratios, while the 4S-related gene groups mainly determined the degradation rate when the C/N ratio was up to 5. Network analysis also shows that the pathway shifts from the Kodama pathway to the 4S pathway occurred through changes in the connections between functional genomes and rates. Furthermore, there were competition and collaboration between the Kodama and 4S pathways. The 4S pathway-related bacteria were more active in estuary wetland sediments compared with reed wetland sediments and tidal wetland sediments. The higher degradation efficiency in estuary wetland sediments may indicate the greater participation of the 4S pathway in the DBT biodegradation reaction. And the effects of ring cleavage of Kodama pathway caused more complete metabolizing of DBT.

关键词： Dibenzothiophene(DBT) Coastal wetlands Functional genes Degradation mechanism Quantitative response relationship Network analysis

Modeling sediment transport in the lower Yellow River and dynamic equilibrium threshold value

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Science China(Technological Sciences) 2004年第Z1期47卷 161-172页

作者： HU Chunhong GUO Qingchao department of sediment China Institute of Water Resources and Hydropower Research Beijing 100044 Department of Sediment China Institute of Water Resources and Hydropower Research Beijing 100044

A major problem in the lower Yellow River is the insufficient incoming water and excessive sediment supply, which results in serious deposition, continuous rise of the river bed, and austere flood control situation. To understand the sediment transport regularity of the lower Yellow River and determine the relationship between sedimentation, incoming water and sediment, and zone water diversion, a mathematical model of the sediment suitable for the characteristics of the lower Yellow River has been developed. This model is first rated and verified by large quantity of observed data, and it is then used to analyze silting reduction for the lower Yellow River by Xiaolangdi Reservoir’s operation, the relationship between zone water diversion and channel sedimentation, and critical equilibrium of sedimentation in the lower Yellow River. The threshold values of equilibrium of sedimentation in the lower Yellow River are estimated and they suggest that deposition in the lower Yellow River can be effectively reduced by the operation of regulating flow and sediment from Xiaolangdi Reservoir, water-soil conservation, and controlling water diversion along the lower Yellow River.

关键词： the lower Yellow River, mathematical model of sediment, threshold value, zone water diversion,sedimentation reduction.

Experimental investigation on local shear stress and turbulence intensities over a rough non-uniform bed with and without sediment using 2D particle image velocimetry

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International Journal of sediment research 2020年第2期35卷 193-202页

作者： Petr Lichtneger Christine Sindelar Johannes Schobesberger Christoph Hauer Helmut Habersack CD-Laboratory of sediment research and Management Institute of Water ManagementHydrology and Hydraulic EngineeringDepartment Water-Atmosphere-EnvironmentUniversity of Natural Resources and Life Sciences

The current work focuses on locally resolving velocities,turbulence,and shear stresses over a rough bed with locally non-uniform character.A nonporous subsurface layer and fixed interfacial sublayer of gravel and sand were water-worked to a nature-like bed form and additionally sealed in a hydraulic flume.Two-dimensional Particle Image Velocimetry(2 D-PIV) was applied in the vertical plane of the experimental flume axis.Runs with clear water and weak sediment transport were done under slightly supercritical flow to ensure sediment transport conditions without formation of considerable sediment deposits or dunes.The study design included analyzing the double-averaged flow parameters of the entire measurement domain and investigating the flow development at 14 consecutive vertical subsections.Local geometrical variabilities as well the presence of sediment were mainly reflected in the vertical velocity component.Whereas the vertical velocity decreased over the entire depth in presence of sediment transport,the streamwise velocity profile was reduced only within the interfacial sublayer.In the region with decelerating flow conditions,however,the streamwise velocity profile systematically increased along the entire depth extent.The increase in the main velocity(reduction of flow resistance)correlated with a decrease of the turbulent shear and main normal stresses.Therefore,effects of rough bed smoothening and drag force reduction were experimentally documented within the interfacial sublayer due to mobile sediment.Moreover,the current study leads to the conclusion that in nonuniform flows the maximum Reynolds stress values are a better predictor for the bed shear stress than the linearly extrapolated Reynolds stress profile.This is an important finding because,in natural flows,uniform conditions are rare.

关键词： Turbulence measurement Local bed shear stress sediment transport and flow interaction Hydraulic flume experiment Particle image velocimetry

Paper sludge as a feasible soil amendment for the immobilization of Pb^(2+)

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Journal of Environmental Sciences 2010年第3期22卷 413-420页

作者： Xiaojia He, Lei Yao, Zhu Liang, Jinren NiThe Key Laboratory of Water and sediment Sciences, Ministry of Education, department of Environmental Engineering, Peking University, Beijing 100871, China. The Key Laboratory of Water and sediment Sciences Ministry of Education Department of Environmental Engineering Peking University Beijing 100871 China

The possibility of amending Pb 2＋ contaminated soil （S） with paper sludge （P） was investigated through adsorption and desorption experiments. The adsorption process of Pb 2＋ in soil containing paper sludge （SP） could be well described by pseudo second-order kinetic model and the Langmuir isotherm model. After P addition, the equilibrium time decreased greatly （from 28 to 8 hr） and the Pb 2＋ maximum adsorbed amount （Q max ） increased by a factor of more than three to 102.04 mg/g. Q max reached its maximum as S：P was 9：1 （m/m） after 10 days contact between S and P. Moreover, Pb 2＋ adsorbed amount increased with the rise of pH during the adsorption process. Desorption experiments indicated that Pb 2＋ adsorption in SP was irreversible. The metal ion fraction was analyzed with Energy Dispersive Spectrometer and Environmental Scan Electron Microscope. As a result, the addition of P to soil was found to induce a decrease in the mobile forms. The Pb 2＋ complexes formation in the presence of carbonates was the main adsorption mechanism. Overall, the paper sludge could be one of the promising soil amendments for the remediation of soil with Pb 2＋ contamination.

关键词： paper sludge pb^2＋ adsorption

On the formation of couplet-style stratifications

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International Journal of sediment research 2008年第1期23卷 85-91页

作者： Yu-Hai WANG1, Yan-Hong WANG2, and Li-Qun TANG31 Ph.D., Engineer, Department of Sediment Research, China Institute of Water Resources and Hydropower research, Chegongzhuangxilu 20, Beijing 100044, China, 2 Ph.D., Engineer, Nanjing Hydraulic research Institute, Hujuguanlu 34, Nanjing 210024, China 3 Ph.D., Prof., Department of Sediment Research, China Institute of Water Resources and Hydropower research, Chegongzhuangxilu 20, Beijing 100044, China Ph.D. Engineer Department of Sediment Research China Institute of Water Resources and Hydropower Research Chegongzhuangxilu 20 Beijing 100044 China Ph.D. Engineer Nanjing Hydraulic Research Institute Hujuguanlu 34 Nanjing 210024 China Ph.D. Prof. Department of Sediment Research China Institute of Water Resources and Hydropower Research Chegongzhuangxilu 20 Beijing 100044 China

Couplet-style stratifications refer to the sedimentary sequences that consist of alternating coarse-grain-dominated bed and fine-grain-dominated bed, with or without a sandwiched middle-sized bed. The formation mechanism is complicated due to the interplays of varying driving force (s), sediment supply & transport and topographic configurations. This paper presents a comprehensive overview of such characteristic bedforms, which emerge during the transport and deposition of non-uniform sediments. The leading formative models include water-stage variation, gravel-overpassing process, superimposition of bedload sheets and avalanching process (inverse grading). Each process might produce similar or distinct sedimentological features with respect to grading, matrix content, grain attitude, bounding faces between beds and internal longitudinal/transverse geometry. The couplet-style stratified strata might play an active role in landscape evolution.

关键词： Couplet-style stratification Formative model sedimentological features Landform

Revisiting functional no-flow events in the Lower Yellow River

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International Journal of sediment research 2016年第4期31卷 351-359页

作者： Rong Huang Tianhong Li Lianjun Zhao School of Environment and Energy Peking University Shenzhen Graduate School department of Environmental Engineering Peking University The Key Laboratory of Water and sediment Sciences Ministry of Education Yellow River Institute of Hydraulic research

Functional no-flow is a topic of considerable interest in the research and management of the Yellow River.The operation of the Xiaolangdi Reservoir has been a source of concern regarding hydraulic characteristics and hydro-environmental responses.However,the impacts of the reservoir on functional no-flow events have not been reported to date.Using a complete set of daily hydrological data from four key hydrological stations for the past six decades and at three different temporal scales(year,wet season and dry season),the differences in incoming water and functional no-flow events have been compared before and after the Xiaolangdi Reservoir began operation,using two sets of critical runoff values that were summarized from previous studies.The results indicate that the frequency of functional no-flow events has decreased since the Xiaolangdi Reservoir began to operate,based on critical runoff or discharge values defined by long term hydrological records,and the frequency decreased more when the critical values defining the new situation were used.However,functional no-flow events still occurred in the Lower Yellow River,especially in the lower reach during the wet season.The degree of severity of the functional no-flow events and the magnitude and variation of daily discharge are strongly linearly related before and after the reservoir began operation,regardless of which set of critical values were used to identify the functional no-flow events.

关键词： Lower Yellow River Incoming water Critical discharge Functional no-flow events Severity level Linear regression

Impact Analysis of Coastal Engineering Projects on Mangrove Wetland Area Change with Remote Sensing

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China Ocean Engineering 2008年第2期22卷 347-358页

作者：李天宏韩鹏赵志杰 department of Environmental Engineering Key Laboratory of Water and Sediment Sciences of Ministry of Education Peking University

In the past decades, two large scale coastal engineering projects have been carried out in the Deep Bay surrounded by Shenzhen City and Hong Kong Special Administrative Region. One project is Shenzhen River channel regulation and the other is the sea reclamation along the seashore on the Shenzhen side. The two projects are very close to the two national nature reserves, specifically Futian in Shenzhen and Mai Po in Hong Kong, which are important wetland ecosystems worldwide. This paper aims to identify and monitor the mangrove wetland changes with time series of Landsat Thematic Mapper images pre and post to the two engineering projects being launched. Coupled analysis of the image interpretation results and tidal data acquired at the same time in the context of the two works reveals that the mangrove wetland area has increased from year 1989 to 1994, and has changed little from year 1994 to 2002. Binary coding is applied to reveal the distribution image of mangrove at each phase, and the coding image shows that the construction of the two coastal engineering projects has caused frequent changes in mangrove spatial distribution. The study also shows that the change is not significant regarding to the precision of the method and the natural evolution of mangrove wetland, and the projects do not cause apparently influences upon the two national mangrove conservation zones at least for the research time period.

关键词： mangrove wetland remote sensing sea reclamation river channel regulation the Deep Bay

Influence of salinity and water content on soil microorganisms

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International Soil and Water Conservation research 2015年第4期3卷 316-323页

作者： Nan Yan Petra Marschner Wenhong Cao Changqing Zuo Wei Qin Department of Sediment Research China Institute of Water Resources and Hydropower ResearchBeijing 100048China research Centre on Soil and Water Conservation of the Ministry of Water Resources Beijing 100048China School of Agriculture Food&WineThe Waite Research InstituteThe University of AdelaideAdelaideSA 5005Australia

Salinization is one of the most serious land degradation problems facing world.Salinity results in poor plant growth and low soil microbial activity due to osmotic stress and toxic ions.Soil microorganisms play a pivotal role in soils through mineralization of organic matter into plant available nutrients.Therefore it is important to maintain high microbial activity in soils.Salinity tolerant soil microbes counteract osmotic stress by synthesizing osmolytes which allows them to maintain their cell turgor and metabolism.Osmotic potential is a function of the salt concentration in the soil solution and therefore affected by both salinity(measured as electrical conductivity at a certain water content)and soil water content.Soil salinity and water content vary in time and space.Understanding the effect of changes in salinity and water content on soil microorganisms is important for crop production,sustainable land use and rehabilitation of saline soils.In this review,the effects of soil salinity and water content on microbes are discussed to guide future research into management of saline soils.

关键词： Salinity Water content Soil microorganism

Critical movement of large rocks in currents and waves

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International Journal of sediment research 2019年第4期34卷 387-398页

作者： L.C.van Rijn LVR-sediment Consultancy

Cobbles, boulders, and rocks often are used in a bed protection layer near a structure to protect the underlying sand bed against erosion by combined current and waves. The design of a bed protection layer consisting of loose rocks(rubble mound) requires knowledge of the stability and movement(as bed load) of very coarse materials. If some movement(or damage) is acceptable, the rock diameter can be designed to be smaller. This paper addresses the stability and movement of very coarse materials(cobbles, boulders, and rocks) based on the concept of the critical Shields mobility number. It is shown that the bed load transport of large cobbles, boulders, and rocks can be described by the equations of Meyer-Peter and Mueller(MPM) and Cheng. Both are valid for relatively small Shields mobility numbers.New and general equations for the design of a bed protection layer(including some permissible damage)in conditions with a current with or without waves are proposed based on the Shields mobility parameter and the bed load transport equation of Cheng. Laboratory and field data of critical velocities for pebbles, cobbles, boulders, and rocks have been analyzed and compared to the computed results of the proposed equations. Practical applications are given to demonstrate the general applicability of the proposed equations.

关键词： Rock stability Bed protection Critical movement Bed load transport Rocks

CML MODELS AND THE NONLINEARITY OF TURBULENCE

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Applied Mathematics and Mechanics(English Edition) 1998年第9期19卷 881-887页

作者：刘兆存 department of sediment China Institute of Water Resources and Hydropower Research Beijing P.R. China

Some new coupled map lattice (CML) models are developed for simulating both convection, diffusion terms and weakly or strongly coupled terms. The structure and features of model are analysed. Numerical results show that the new models are effective for studying spatiotemporal chaos. Finally, the mechanism of turbulence is analysed via the numerical results.

关键词： CML model spatiotemporal chaos turbulence