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A new era of flood control strategies from the perspective of managing the 2020 Yangtze River flood

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Science China Earth Sciences 2021年第1期64卷 1-9页

作者： Jun xia Jin CHEN State Key Laboratory of Water Resources and Hydropower Engineering Sciences Wuhan UniversityWuhan 430072China Wuhan University Yangtze River Academy of SciencesChangjiang Water Resources Commission of the Ministry of Water ResourcesWuhan 430015China

Flood control of the Yangtze River is an important part of China’s national water *** July 2020,due to continuous heavy rainfall,the water levels along the middle-lower reaches of the Yangtze River and major lakes constantly exceeded the warning levels,in which Taihu Lake exceeded its highest safety water level and some stations of Poyang Lake reached their highest water levels in its *** August 2020,another huge flood occurred in the Minjiang River and the Jialing River in the upper Yangtze River,and some areas of Chongqing Municipality and other cities along the rivers were inundated,resulting in great pressure on flood control and high disaster *** 2020 Yangtze River flood has received extensive media coverage and raised concerns on the roles of the Three Gorges Dam and other large reservoirs in flood *** we analyze the changes in the pattern of the Yangtze River flood control by comparing the strategies to tackle the three heavy floods occurring in 1954,1998,and *** propose that the overall strategy of the Yangtze River flood control in the new era should adhere to the principle of"Integration of storage and drainage over the entire Yangtze River Basin,with draining floods downstream as the first priority"by using both engineering and non-engineering *** the basis of embankments,the engineering measures should use the Three Gorges Dam and other large reservoirs as the major regulatory means,promote the construction of key flood detention areas,keep the floodways clear,and maintain the ecosystem services of wetlands and *** terms of non-engineering measures,we should strengthen adaptive flood risk management under climate change,standardize the use of lands in flood detention areas,give space to floods,and promote the implementation of flood risk maps and flood insurance *** ultimate goal of this new flood control system is to enhance the adaptability to frequent floods and increase the resilience to extre

关键词： The 2020 Yangtze River flood Yangtze River Flood Control System Three Gorges Dam Protection of wetlands and shoals Non-engineering measures

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从情景到情境的小学英语对话教学设计研究

教学与管理 2025年第2期 43-46页

作者：李海霞汤焱昊北京联合大学师范学院

《义务教育英语课程标准（2022年版）》提出英语课程目标是培养学生的核心素养，并主张围绕“情境”进行学习来实现目标。但是，教师往往难以区分“情景”和“情境”，在教学实践中用“情景”代替“情境”的做法比较普遍。针对这个问题... 详细信息

《义务教育英语课程标准（2022年版）》提出英语课程目标是培养学生的核心素养，并主张围绕“情境”进行学习来实现目标。但是，教师往往难以区分“情景”和“情境”，在教学实践中用“情景”代替“情境”的做法比较普遍。针对这个问题，结合小学具体教学案例，提出从创设前置情境、连贯情境和拓展性情境三个方面实现从“情景教学”到“情境教学”，从而培养学生核心素养，实现小学英语课程育人目标。

关键词：情景情境对话教学核心素养小学英语

Nitrogen-,phosphorus-doped carbon-carbon nanotube CoP dodecahedra by controlling zinc content for high-performance electrocatalytic oxygen evolution

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Rare Metals 2020年第6期39卷 680-687页

作者： xia-xia Li Pei-Yao Zhu Qing Li Yu-xia Xu Yan Zhao Huan Pang School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhou 225009China Guangling College Yangzhou UniversityYangzhou 225000China College of Chemistry and Materials Science Sichuan Normal UniversityChengdu 610068China

Here,N-and P-doped carbon-carbon nanotube CoP(NPC-CNTs-CoP)nanoparticles dodecahedra are achieved by multistep calcination of the Zn-doped zeolitic imidazolate framework ZIF-67 precursor(ZnCo-ZIF).In the structures,the presence of N and P atoms,abundant CNTs and the CoP nanoparticles can enhance electrochemical activity and promote the structural stability of *** the temperature increases,the Zn contents gradually reduce to zero,which provides more active sites for electrochemical ***,the high specific surface area and microporous behavior of NPC-CNTsCoP-9 make it excellent in electrocatalytic ***-CoP-9 shows a low overpotential of 224 mV at10 mA·cm^-2 in 1.0 mol·L^-1 KOH *** strategy of zeolitic imidazole framework-derived transition metal phosphides will provide a new sight for developing energy conversion materials.

关键词： Nitrogen Phosphorus Carbon Carbon nanotube CoP Oxygen evolution

Computational modelling of gas–liquid–solid multiphase free surface flow with and without evaporation

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Particuology 2024年第7期90卷 218-235页

作者： Huihuang xia Marc Kamlah Institute for Applied Materials(IAM) Karlsruhe Institute of Technology(KIT)Hermann-von Helmholtz-Platz 176344 Eggenstein-LeopoldshafenGermany

Gas–liquid–solid multiphase systems are ubiquitous in engineering applications,*** printing,spray drying and *** a numerical framework for modelling these multiphase systems is of great *** improved,resolved computational fluid dynamics-discrete element method(CFD-DEM)framework is developed to model the multiphase free surface flow with and without *** improved capillary force model is developed to compute the capillary interactions for partially floating particles at a free *** well-known benchmark cases,namely drag coefficient calculation,the single sphere settling,and drafting-kissing-tumbling of two particles are conducted to validate the resolved CFD-DEM *** turns out that the resolved CFD-DEM model developed in this paper can accurately calculate the fluid–solid interactions and predict the trajectory of solid particles interacting with the liquid *** demonstrations,namely two particles moving along a free surface when the liquid phase evaporates,and particle transport and accumulations inside an evaporating sessile droplet show the performance of the resolved model.

关键词： Capillary force Discrete element method Liquid bridge Particle transport Resolved CFD-DEM Volume of fluid

Simulation of plasma behavior for medium propellant mass and pulsed energy of small scale pulsed inductive thruster

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Chinese Journal of Aeronautics 2020年第1期33卷 176-190页

作者： Yuguo CHENG Guangqing xia PLA 91550 Element 41 Dalian 116023China State Key Laboratory of Structural Analysis for Industrial Equipment Dalian University of TechnologyDalian 116024China Key Laboratory of Advanced Technology for Aerospace Vehicles of Liaoning Province Dalian University of TechnologyDalian 116024China

The pulsed inductive thruster is characterized of no electrode corruption and wide propellant *** give insight into the propulsion mechanism of small scale thruster at different propellant mass(m)and energy(E)levels,the transient Magneto Hydro Dynamics(MHD)method,completed by high temperature thermodynamic and transport,and plasma electrical models,is developed to study argon plasma response under the excitation of current of high rise *** calculating the two-dimensional expansion properties of the thruster with conical pylon,the simulations find that the main energy deposition occurs during the initial pulse rise stage,and the energy density of Joule heat is two magnitudes higher than the deposition in the down *** propellant mass of 2 mg,average axial velocity of the current sheet increases from about 15 km/s at 750 J to about 21 km/s at 1470 J within the decoupling *** velocity variation synchronizes with the pulsed rise in the *** monotonically decrease of the temperature along axis results in the growth of low ionization level ions and reducing of high *** current sheet maintains the structure formed during the initial pulse rise when moving beyond the decoupling *** the change in forward velocity,the main difference is the dimension compared with that in the first half period,caused by thermal conduction and particle *** variations of total impulse It in the range of m from 2 mg to8 mg and E from 750 J to 1470 J show that It is proportional to m1/2 when E is determined.

关键词： Expansion properties Flow field Magneto Hydro Dynamics(MHD)method Pulsed inductive plasma Total impulse

Spinel Li Mn_(2)O_(4)integrated with coating and doping by Sn self-segregation

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International Journal of Minerals,Metallurgy and Materials 2022年第5期29卷 909-916页

作者： Huaifang Shang Dingguo xia Key Laboratory of Magnetic Molecules and Magnetic Information Materials(Ministry of Education) School of Chemistry and Material ScienceShanxi Normal UniversityTaiyuan 030031China Beijing Key Laboratory of Theory and Technology for Advanced Batteries Materials School of Materials Science and EngineeringPeking UniversityBeijing 100871China

The development of high-performance and low-cost cathode materials is of great significance for the progress in lithium-ion *** use of Co and even Ni is not conducive to the sustainable and healthy development of the power battery industry owing to their high cost and limited ***,we report LiMn_(2)O_(4)integrated with coating and doping by Sn *** electron energy spectrum and soft X-ray absorption spectrum show that the coating is Sn-rich LiMn_(2)O_(4),with a small Sn doping in the bulk *** integration strategy can not only mitigate the Jahn–Teller distortion but also effectively avoid the dissolution of *** as-obtained product demonstrates superior high initial capacities of 124 mAh·g^(-1)and 120 mAh·g^(-1)with the capacity retention of 91.1%and 90.2%at 25℃and55℃after 50 cycles,*** novel material-processing method highlights a new development direction for the progress of cathode materials for lithium-ion batteries.

关键词： spinel lithium manganate coating and doping tin self-segregation high capacity good stability

Seasonal thermal energy storage using natural structures:GIS-based potential assessment for northern China

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Building Simulation 2024年第4期17卷 561-574页

作者： Yichi Zhang Jianjun xia Midea HVAC Heating&Ventilation Equipment Co. LtdFoshan528311China Building Energy Research Center Tsinghua UniversityBeijing100084China

Seasonal thermal energy storage(STES)allows storing heat for long-term and thus promotes the shifting of waste heat resources from summer to winter to decarbonize the district heating(DH)*** being a promising solution for sustainable energy system,large-scale STES for urban regions is lacking due to the relatively high initial investment and extensive land *** close the gap,this study assesses the potentials of using two naturally available structures for STES,namely valley and ground pit *** on geographical information system(GIS)methods,the available locations are searched from digital elevation model and selected considering several criteria from land uses and construction *** costs of dams to impound the reservoir and the yielded storage capacities are then quantified to guide the choice of suitable *** assessment is conducted for the northern China where DH systems and significant seasonal differences of energy demand *** total,2,273 valley sites and 75 ground pit sites are finally identified with the energy storage capacity of 15.2 billion GJ,which is much larger than the existing DH demand in northern *** results also prove that 682 valley sites can be achieved with a dam cost lower than 20 CNY/m^(3).By conducting sensitivity analysis on the design dam wall height and elevations,the choices of available natural structures are expanded but practical issues about water pressures and constructions are also ***,the identified sites are geographically mapped with nearest urban regions to reveal their roles in the DH *** general,560 urban regions are found with potential STES units and most of them have STES storage capacities larger than their own DH *** novel planning methodology of this study and publicly available datasets create possibilities for the implementations of large-scale STES in urban DH systems.

关键词： seasonal thermal energy storage geographical information system district heating water reservoir

Investigation into the transient flow characteristics of noble gas propellants using the pulsed inductive discharge in electric propulsion

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Chinese Journal of Aeronautics 2020年第9期33卷 2329-2341页

The Pulsed Inductive Thruster(PIT)has the advantages of repeatable startup,no corruption and in-situ propellant *** study the flow expansion and circuit characteristics of PITs,the circuit-fluid model is developed,and the high temperature thermodynamic and transport models are combined with the circuit-fluid model to predict the critical plasma *** flow fields of initial mass of 2–8 mg and charge voltages of 10–14 k V are *** of the flow fields of argon and helium propellants suggests that,the flow field structures are *** differences exist on the magnitude of the density and magnetic field,caused by larger velocity in lighter atom case and difference on the ionization gap between adjacent ionization *** of the circuit characteristics by the two-dimensional results indicates that the ratio of coil inductance to circuit inductance affects both the rise rate and phase of the plasma current,the larger the ratio,the greater the rise rate and the better the following *** calculations show that the magnetic energy obtained within the decoupling distance determines the overall performance the thruster can be obtained;self-induced field maintained by the thermal motion after the main pulse leads to the long attenuation process and difference on the total impulse when the angle of conical pylon is varied under constant coil dimension.

关键词： Argon and helium propellants Circuit characteristics Circuit-fluid model Flow properties Pulsed inductive thruster

Synthesis and mechanism analysis of a new oil soluble viscosity reducer for flow improvement of Chenping heavy oil

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Chinese Journal of Chemical Engineering 2022年第5期35卷 58-67页

作者： Yaqi Ren Shuqian xia School of Chemical Engineering and Technology Tianjin UniversityTianjin 300072China

Oil soluble viscosity reducers have gradually attracted the attention of petrochemical research due to their cleanliness and high *** the high viscosity and non-Newtonian fluid properties of Chenping heavy oil found in China,a series of new oil soluble viscosity reducers with different proportions and molecular weights were prepared by free radical polymerization using octadecyl acrylate,2-allylphenol and N-methylolacrylamide as *** viscosity reducer was applied to different types of heavy oil and found that it exhibited a better effect on heavy oils with high asphaltene *** test of rheological behavior of heavy oil with additive was performed at wide range of shear rate(3–90 s^(-1))and temperature range(30–100°C).The apparent viscosity reduction rate was up to 70.09%,which was better than the industrially relevant ethylene–vinyl acetate copolymer under the same test *** addition,the effect of viscosity reducers on the components of heavy oil and the energy change of the system simulated by molecular dynamics simultaneously was *** consistency of the simulated and experimental results show that the effect of viscosity reduction closely related to the crystallization process of wax and the viscosity reducer can reconstruct the surface structure of asphaltene and diminish the connection of benzene ring.

关键词： Heavy oil Viscosity reduction Asphaltene Non-Newtonian fluid