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STOCHASTIC PROCESS OF SEDIMENT IN SEDIMENTATION BASIN

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Journal of Hydrodynamics 1992年第4期4卷 66-71页

作者： Zheng, Bongmin fang, hongwei Wuhan Univ of Hydraulic and Electric Engineering Wuhan China

Suspended movement is supported by eddy of river. In this paper the turbulent stochastic regularity of flow and sediment was adopted and the settling model of the suspended movement was established. Then, stochastic regularity of the sediment in sedimentation basin was investigated. The calculating results were compared with measured data. The results are in good agreement and the calculating method is very simple. The divided diameter of washload and bed material load was discussed from the relation of turbulent intensity and sediment settling velocity.

关键词： Flow of water Sediment transport Sedimentation Turbulence

Analysis of the complex morphology of sediment particle surface based on electron microscope images

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Science China(Technological Sciences) 2013年第2期56卷 280-285页

作者： CHEN ZhiHe fang hongwei Department of Water Resources and Environment Geography and Planning School of Sun Yat-sen University Key Laboratory of Water Cycle and Water Security in Southern China of Guangdong High Education Institute State Key Laboratory of Hydroscience and Engineering Tsinghua University

The morphology of sediment particles plays an important role in interfacial *** difficulties in complex morphological description significantly limit the research on interfacial *** this study,images of a single sediment particle extracted from electron microscope photos were used to analyze the gray values and present the probability of shape of the sediment ***,the morphological features of the sediment particles were qualitatively described using the fractal method(surface area-volume method).The fractal dimension D of a single sediment particle was calculated to analyze the features and quantitative complexity of the sediment particle *** indicate that the probability of shape can provide intuitive morphological structure and fully describe the complex morphological characteristics of sediment particle *** fractal dimension abstractly described the complexity of the morphology of a sediment particle surface and matched well with the experimental *** methods discussed in this study are suitable for describing the complex morphology of the sediment particle surface and lay the scientific foundation for further research on the interfacial interaction between the sediment particle and the pollutant.

关键词： sediment particles surface morphology probability of shape fractal dimension

Luminescence of halophosphate solid-solution Ca5(PO4)3(F0.8Cl0.2)：Eu^2＋,Mn^2＋ for WLED

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Journal of Rare Earths 2018年第11期36卷 1157-1161页

作者： Jiashan Mao hongwei fang Yonghu Chen Department of Physics University of Science and Technology of China Hefei 230026 China The Science and Technology Department of Fujian Province Fuzhou 350003 China

Solid-solution based luminescent materials have been widely explored due to their tunable optical properties in recent years. In this work, instead of more common cation-substitution approach, we investigated the luminescence properties of Eu^2＋ and Mn^2 ＋ co-doped halophosphate solid solution Ca5（PO4）3（F0.8Cl0.2） via anion substitution synthesized by high temperature solid state reaction method. The formation of the solid solution was confirmed by X-ray diffraction （XRD） characterization, which indicates that the introduction of certain proportion of CI will not make significant change on the CaB（PO4）3F lattice, We also studied the energy transfer from Eu^2＋ to Mn^2＋ in the host so as to obtain white light emission via adjusting the doping concentrations of Eu^2＋ and Mn^2＋, The white light emission was achieved through combination of Eu^2＋ blue emission and Mn^2＋ red-orange emission with appropriate proportions. The results suggest that Ca5（PO4）3（F0.8Cl0.2）：0.01Eu^2＋＋,0.18Mn^2＋ could be a potential WLED phosphor working under ultraviolet excitation,

关键词： WLED Rare earth Transition metal Luminescence Energy transfer

Surface pore tension and adsorption characteristics of polluted sediment

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Science China(Physics,Mechanics & Astronomy) 2008年第8期51卷 1022-1028页

作者： fang hongwei CHEN MingHong CHEN ZhiHe Department of Hydraulic Engineering State Key Laboratory of Hydro-science and EngineeringTsinghua UniversityBeijing 100084China

Most natural sediment particles have numerous pores and a complex surface texture which facilitates their adsorption of contaminants. Particle surface structure,therefore,is an important instrumental factor in the transport of contaminants,especially in water environments. This paper reports on the results of adsorption-desorption experiments to analyze polluted sediment surface pore tension characteristics performed on samples from the bottom of Guanting Reservoir. In our analysis,the Frenkel-Halsey-Hill(FHH) equation is applied to calculate the fractal dimensions of particles to quantify the surface roughness and pore tension characteristics. The results show that the surface fractal dimensions of sediment particle surfaces normally measure from 2.6 to 2.85. The volume of pores smaller than 10 nm changes significantly after being contaminated with pollutants and the fractal dimension decreases because the pores adsorb the contaminants.

关键词： sediment pollution pore distribution fractal dimension adsorption mechanics

Design of Permanent Magnet Synchronous Generators for Wave Power Generation

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Transactions of Tianjin University 2016年第5期22卷 396-402页

作者： fang hongwei Wang Dan School of Electrical Engineering and Automation Tianjin University

In this paper, a design method for ocean wave permanent magnet synchronous generator(PMSG)is proposed with new performance criteria to obtain better output performance at the cost of less permanent magnet material. Besides, a simple equivalent analytical geometry method is put forward to calculate the sizes of permanent magnets. Based on geometric and electromagnetic models, four types of rotor structures are compared, i.e., embedded, tangential, tile surface mount and convex surface mount structures. The designs and comparisons of machine are performed with the same permanent magnet volume. Moreover, the influences of mechanical pole-arc coefficient of tile surface mount PMSG on electrical efficiency, output power, material corrosion, core loss, and torque ripple are investigated. Finite-element analysis method is applied to verify the results using Ansoft/Maxwell.

关键词： analytical geometry method mechanical pole-arc coefficient ocean wave power generation permanent magnet synchronous generator

A model of ^90Sr distribution in the sea near Daya Bay Nuclear Power Plant in China

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Frontiers of Environmental Science & Engineering 2014年第6期8卷 845-853页

作者： Jingyu WANG hongwei fang Guojian HE Lei HUANG The State Key Laboratory of Hydro Science and Engineering Department of Hydraulic Engineering Tsinghua University Beijing 100084 China

The impact on the environment ofradionuclide release from nuclear power plants has attracted increased attention, especially after the accident at Fukushima Daiichi Nuclear Power Plant in Japan. Based on the mechanisms of adsorption/desorption at solid/liquid interfaces and a surface micromorphology model of sediments, a theoretical expression of the distribution coefficient Kd is derived. This coefficient has significant effects on the distribution of radionuclide in seawater, suspended sediment and seabed sediment. Kd is then used to simulate ^90Sr transport in the sea near the Daya Bay Nuclear Power Plant. The simulation results are compared with field measurements of tidal level, current velocity, suspended sediment concentration and ^90Sr concentrations in the same period. Overall, the simulated results agree well with the field measured data. Thus, the derived expression for Ka is capable of interpreting realistic adsorption/desorption processes. What＇s more, conclusion is drawn that about 40% ^90Sr released by Daya Bay Nuclear Power Plant will be adsorbed by suspended sediment and 20% by seabed sediment, only about 40% ^90St will remain in the sea near Daya Bay Nuclear Power Plant in South China Sea.

关键词： distribution coefficient Daya Bay hydrodynamic sediment transport radionuclide transport

Design and analysis of bidirectional driven float-type wave power generation system

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Journal of Modern Power Systems and Clean Energy 2018年第1期6卷 50-60页

作者： hongwei fang Yue TAO Shuai ZHANG Zhaoxia XIAO School of Electrical Engineering and Automation Tianjin University School of Electrical Engineering and Automation Tianjin Polytechnic University

The dynamic model for a bidirectional driven float-type wave power generation system design is presented in this *** gravity,buoyancy and drag force acting on the wave energy converter(WEC)are all *** analytical expression of the torque applied on the rotor is given based on a linear model of the switched reluctance generator(SRG).The SRG usually rotates with low velocity in the WEC *** this situation,current chopping control(CCC)is adopted with fixed turn-on angle and turn-off angle control mode to have a quick response for ***,in order to make the float keep in phase with the wave so as to improve the power generation efficiency,the reference current is dynamically adjusted according to the wave motion at all working *** maximum power point tracking(MPPT)of system is achieved.A simulation model is developed in MATLAB for the bidirectional driven float-type wave power generation system with real wave statistical characteristics taken into *** results show that the WEC can output desired torque periodically with high efficiency and good ***,the feasibility of applying a SRG in a WEC is also verified.

关键词： Wave energy converter Force analysis Current chopping control Dynamical reference current setting Maximum power point tracking

From fluvial dynamics to eco-fluvial dynamics

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International Journal of Sediment Research 2019年第6期34卷 531-536页

作者： Guojian He hongwei fang Jianyu Wang Tao Zhang State Key Laboratory of Hydro-science and Engineering Department of Hydraulic EngineeringTsinghua University

Sediment plays a very important role in the functioning of river *** is the basic substance for the survival of benthic animals and aquatic *** the other hand,the growth of biofilms and biodisturbance of benthos affect the sediment transport *** the increasing attention to protect aquatic ecosystems,the importance of habitats has become increasingly *** need to study the interactions among sediment,flow,riverbed deformation,and aquatic ecosystems naturally leads to the proposed discipline of eco-fluvial *** this paper,the basic concept and main research content of eco-fluvial dynamics is introduced with the Yarlung Tsangpo River as the research *** case study is an example of an aquatic ecosystem in an ever-changing environment because of the effects of climate *** results of analysis of eco-fluvial dynamics will provide a scientific basis for decision support for the government.

关键词： Fluvial dynamics Eco-fluvial dynamics Water and sediment transport Aquatic ecosystems Interactive response

Fluvial processes and their impact on the finless porpoise's habitat after the Three Gorges Project became operational

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Science China(Technological Sciences) 2014年第5期57卷 1020-1029页

作者： fang hongwei HE GuoJian HAN Dong DUAN JieHui HUANG Lei CHEN MingHong Department of Hydraulic Engineering Tsinghua University State Key Laboratory of Hydro-science and Engineering Tsinghua University Hydro-China Corporation China Institute of Water Resources and Hydropower Research College of Water Conservancy and Civil Engineering China Agricultural University

Since the filling of the reservoir of the Three Gorges Project(TGP)dam in the Yangtze River in 2003,erosion downstream from the dam site has affected the finless porpoise’s *** this study,a one-dimensional(1D)fluvial process mathematical model is used to calculate flow and sediment transport in the middle and lower reaches of the Yangtze River,including the finless porpoise’s *** analyzing the calculation results for the water resources,suspended load,and bed materials in the finless porpoise’s habitat after the riverbed deformation,we evaluated the possible impact on this rare Yangtze River aquatic *** results show that,with the erosion of riverbed over the next 20 years,the water quantity comprising the habitat will decrease to half of its present amount,and the bed materials will be eroded to coarse grading,such that the reserve will become a gradually disappearing *** engineering measures should be used to decrease the erosion in the main channel,in case the overall erosion cannot be stemmed and controlled,to ensure an adequate water volume flows into the finless porpoise’s habitat.

关键词： fluvial process finless porpoise habitat Three Gorges Project water resource bed materials