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Coupling of RANS and BEM Solvers for Simulation of Propeller Behind the Hull in Full Appended Model

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China Ocean Engineering 2024年第3期38卷 424-438页

作者： Saeed NAJAFI Mehdi POURMOSTAFA LIU Peng-fei Iranian National Institute for Oceanography and atmospheric {1.(INIOAS) Tehran 14155-4781Iran department of Maritime Engineering Amir Kabir University of TechnologyTehran 15875-4413Iran Marine Offshore and Subsea TechnologySchool of EngineeringNewcastle UniversityNewcastle upon TyneNE17RUUK

To design a propeller for ship power plant,the interaction between ship hull and propeller must be taken into *** main concern is to apply the wake effect of ship stern on the propeller *** this paper,a coupled BEM(Boundary Element Method)/RANS(Renolds-Averaged Navier−Stokes)solver is used to simulate propeller behind the hull in the self-propulsion *** motivation of this work is to develop a practical tool to design marine propulsion system without suffering long computational *** unsteady boundary element method which is also known as panel method is chosen to estimate the propeller *** wakes are treated using a time marching wake alignment ***,a RANS code coupled with VoF equation is developed to consider the ship motions and wake field effects in the problem.A coupling algorithm is developed to interchange ship wake field to the potential flow solver and propeller thrust to the RANS *** on the difference between hull resistance and the propeller thrust,a PI controller is developed to compute the propeller RPM in every time *** of the solver is carried out using the towing tank test report of a 50 m oceanography research *** factor and trust deduction coefficient are estimated ***,the wake rollup pattern of the propeller in open water is compared with the propeller in real wake field.

关键词： RANS BEM coupled method ship propeller self-propulsion wake sheet pattern

Ground Passive Microwave Remote Sensing of atmospheric Profiles Using WRF Simulations and Machine Learning Techniques

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Journal of Meteorological Research 2024年第4期38卷 680-692页

作者： Lulu ZHANG Meijing LIU Wenying HE Xiangao XIA Haonan YU Shuangxu LI Jing LI department of {1. and Oceanic sciences School of PhysicsPeking UniversityBeijing 100871 Key Laboratory of Middle Atmosphere and Global Environment Observation(LAGEO) Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029 University of Chinese Academy of sciences Beijing 101408

Microwave radiometer(MWR) demonstrates exceptional efficacy in monitoring the atmospheric temperature and humidity profiles.A typical inversion algorithm for MWR involves the use of radiosonde measurements as the training ***,this is challenging due to limitations in the temporal and spatial resolution of available sounding data,which often results in a lack of coincident data with MWR deployment *** study proposes an alternative approach to overcome these limitations by harnessing the Weather Research and Forecasting(WRF) model's renowned simulation capabilities,which offer high temporal and spatial *** using WRF simulations that collocate with the MWR deployment location as a substitute for radiosonde measurements or reanalysis data,our study effectively mitigates the limitations associated with mismatching of MWR measurements and the sites,which enables reliable MWR retrieval in diverse geographical *** machine learning(ML) algorithms including extreme gradient boosting(XGBoost),random forest(RF),light gradient boosting machine(LightGBM),extra trees(ET),and backpropagation neural network(BPNN) are tested by using WRF simulations,among which BPNN appears as the most superior,achieving an accuracy with a root-mean-square error(RMSE) of 2.05 K for temperature,0.67 g m~(-3) for water vapor density(WVD),and 1..98% for relative humidity(RH).Comparisons of temperature,RH,and WVD retrievals between our algorithm and the sounding-trained(RAD) algorithm indicate that our algorithm remarkably outperforms the *** study verifies the feasibility of utilizing WRF simulations for developing MWR inversion algorithms,thus opening up new possibilities for MWR deployment and airborne observations in global locations.

关键词： microwave radiometer(MWR) Weather Research and Forecasting(WRF)model extreme gradient boosting(XGBoost) random forest(RF) light gradient boosting machine(LightGBM) extra trees(ET) backpropagation neural network(BPNN) monochromatic radiative transfer model(MonoRTM)

Investigating the effect of volatility on the hygroscopicities of acetate nanoparticle aerosols by surface plasmon resonance microscopy

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Journal of Environmental sciences 2024年第4期138卷 167-178页

作者： Bo Yang Zhibo Xie Jianguo Liu Huaqiao Gui Jiaoshi Zhang Xiuli Wei Zetao Fan Douguo Zhang Key Laboratory of Environmental Optics and Technology Anhui Institute of Optics and Fine MechanicsHefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China University of science and Technology of China Hefei 230026China CAS Center for Excellence in Regional atmospheric Environment Institute of Urban EnvironmentChinese Academy of SciencesXiamen 361021China Advanced Laser Technology Laboratory of Anhui Province Department of Optics and Optical EngineeringUniversity of Science and Technology of ChinaHefei 230026China

Under high relative humidity(RH)conditions,the release of volatile components(such as acetate)has a significant impact on the aerosol *** this work,one surface plasmon resonance microscopy(SPRM)measurement system was introduced to determine the hygroscopic growth factors(GFs)of three acetate aerosols separately or mixed with glucose at different *** Ca(CH_(3)COO)_(2) or Mg(CH_(3)COO)_(2) aerosols,the hygroscopic growth trend of each time was lower than that of the previous time in three cyclic humidification from 70% RH to 90% RH,which may be due to the volatility of acetic acid leading to the formation of insoluble hydroxide(Ca(OH)_(2) or Mg(OH)_(2))under high RH *** the third calculated GF(using the Zdanovskii-Stokes-Robinson method)for Ca(CH_(3)COO)_(2) or Mg(CH_(3)COO)_(2) in bicomponent aerosols with 1.1.mass ratio were 3.20% or 5.33% lower than that of the first calculated GF at 90% *** calculated results also showed that the hygroscopicity change of bicomponent aerosol was negatively correlated with glucose content,especially when the mass ratio of Mg(CH_(3)COO)_(2) to glucose was 1.2,the GF at 90% RH only decreased by4.67% after three cyclic *** coupled plasma atomic emission spectrum(ICP-AES)based measurements also indicated that the changes of Mg^(2+)concentration in bicomponent was lower than that of the *** results of this study reveal thatduring the efflorescence transitions of atmospheric nanoparticles,the organic acids diffusion rate may be inhibited by the coating effect of neutral organic components,and the particles aging cycle will be prolonged.

关键词： Hygroscopic growth Volatility Acetate aerosols Nanoparticle aerosol Surface plasmon resonance

Convection-Permitting Simulations of Current and Future Climates over the Tibetan Plateau

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Advances in atmospheric {1.s 2024年第10期41卷 1901-1916页

作者： Liwei ZOU Tianjun ZHOU LASG Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China

The Tibetan Plateau(TP)region,also known as the“Asian water tower”,provides a vital water resource for downstream *** studies of water cycle changes over the TP have been conducted with climate models of coarse resolution in which deep convection must be *** this study,we present results from a first set of highresolution climate change simulations that permit convection at approximately 3.3-km grid spacing,with a focus on the TP,using the Icosahedral Nonhydrostatic Weather and Climate Model(ICON).Two 1.-year simulations were performed,consisting of a retrospective simulation(2008–20)with initial and boundary conditions from ERA5 reanalysis and a pseudoglobal warming projection driven by modified reanalysis-derived initial and boundary conditions by adding the monthly CMIP6 ensemble-mean climate change under the SSP5-8.5 *** retrospective simulation shows overall good performance in capturing the seasonal precipitation and surface air *** the central and eastern TP,the average biases in precipitation(temperature)are less than−0.34 mm d−1.−1.1.)throughout the *** simulated biases over the TP are ***(wet)biases are found in summer(winter)above 5500 *** future climate simulation suggests that the TP will be wetter and warmer under the SSP5-8.5 *** general features of projected changes in ICON are comparable to the CMIP6 ensemble projection,but the added value from kilometer-scale modeling is evident in both precipitation and temperature projections over complex topographic *** ICON-downscaled climate change simulations provide a high-resolution dataset to the community for the study of regional climate changes and impacts over the TP.

关键词： dynamical downscaling convection-permitting Tibetan Plateau pseudo-global warming

On the topological surface states of the intrinsic magnetic topological insulator Mn-Bi-Te family

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National science Review 2024年第2期11卷 50-64页

作者： Yuan Wang Xiao-Ming Ma Zhanyang Hao Yongqing Cai Hongtao Rong Fayuan Zhang Weizhao Chen Chengcheng Zhang Junhao Lin Yue Zhao Chang Liu Qihang Liu Chaoyu Chen Shenzhen Institute for Quantum science and Engineering(SIQSE)and {1. of Physics Southern University of Science and Technology(SUSTech)

We review recent progress in the electronic structure study of intrinsic magnetic topological insulators（MnBi2Te4）·（Bi2Te3）n（n = 0, 1. 2, 3） family. Specifically, we focus on the ubiquitously（nearly）gapless behavior of the topological Dirac surface state observed by photoemission spectroscopy, even though a large Dirac gap is expected because of surface ferromagnetic order. The dichotomy between experiment and theory concerning this gap behavior is perhaps the most critical and puzzling question in this frontier. We discuss various proposals accounting for the lack of magnetic effect on the topological Dirac surface state, which are mainly categorized into two pictures, magnetic reconfiguration and topological surface state redistribution. Band engineering towards opening a magnetic gap of topological surface states provides great opportunities to realize quantized topological transport and axion electrodynamics at higher temperatures.

关键词： intrinsic magnetic topological insulator topological surface states magnetic gap magnetic reconfiguration topological surface state redistribution van der Waals spacing expansion

Confluence of ZnO and PTFE Binder for Enhancing Performance of Thin-Film Lithium-Ion Batteries

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Energy & Environmental Materials 2024年第5期7卷 52-60页

作者： Subhashree Behera Swathi Ippili Venkatraju Jella Na-Yeong Kim Seong Cheol Jang Ji-Won Jung Soon-Gil Yoon Hyun-Suk Kim department of Materials {1. and Engineering Chungnam National University School of Materials science and Engineering University of Ulsan department of Energy and Materials Engineering Dongguk University

Developing anode materials with high specific capacity and cycling stability is vital for improving thin-film lithium-ion batteries. Thin-film zinc oxide （ZnO）holds promise due to its high specific capacity, but it suffers from volume changes and structural stress during cycling, leading to poor battery performance. In this research, we ingeniously combined polytetrafluoroethylene （PTFE） with ZnO using a radio frequency （RF）magnetron co-sputtering method, ensuring a strong bond in the thin-film composite electrode. PTFE effectively reduced stress on the active material and mitigated volume change effects during Li+ion intercalation and deintercalation. The composite thin films are thoroughly characterized using advanced techniques such as X-ray diffraction, scanning electron microscopy,and X-ray photoelectron spectroscopy for investigating correlations between material properties and electrochemical behaviors. Notably, the ZnO/PTFE thin-film electrode demonstrated an impressive specific capacity of1.05 mAh g-1.=71.6 mAh cm-3) at a 0.5C rate and a remarkable capacity retention of 82%from the 1.t to the 1.0th cycle, surpassing the bare ZnO thin film （50%）. This study provides valuable insights into using binders to stabilize active materials in thin-film batteries, enhancing battery performance.

关键词： li-ion batteries metal oxides anodes polytetrafluoroethylene (PTFE) thin films

Homovalent doping: An efficient strategy of the enhanced TiNb2O7 anode for lithium-ion batteries

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Green Energy & Environment 2024年第8期9卷 1257-1266页

作者： Xiaohe Jin Yirui Deng Han Tian Miaomiao Zhou Wenhao Tang Huiyou Dong Xinquan Zhang Ruiping Liu department of Materials {1. and Engineering China University of Mining & Technology (Beijing) department of Materials {1. and Engineering China University of Mining&Technology (Beijing)

The low energy density,unsatisfied cycling performance,potential safety issue and slow charging kinetics of the commercial lithium-ion batteries restrained their further application in the fields of fast charging and long-haul electric *** TiNb2O7（TNO） with the theoretical capacity of 387 mAh g-1.as been proposed as a high-capacity anode materials to replace *** this work,homovalent doping strategy was used to enhance the electrochemical performance of Ti Nb2O7（TNO） by employing Zr to partial substitute Ti through solvothermal *** doping of Zr4+ions can enlarge the lattice structure without changing the chemical valence of the original elements,refine and homogenize the grains,improve the electrical conductivity,and accelerate the ion diffusion kinetics,and finally enhance the cycle and rate ***,Z0.05-TNO shows initial discharge capacity of as high as 31..2 mAh g-1.t 1.C and 244.8 mAh g-1.t 1. C,and still maintains a high specific capacity of 1.1.3 mAh g-1.fter 800 cycles at 1. *** study provides a new strategy for high-performance fastcharging energy storage electrodes.

关键词： Homovalent doping Zr 4+ TiNb 2 O 7 Microsphere Lithium-ion batteries

Investigation of formaldehyde sources and its relative emission intensity in shipping channel environment

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Journal of Environmental sciences 2024年第8期142卷 142-154页

作者： Jiaqi Liu Shanshan Wang Yan Zhang Yuhao Yan Jian Zhu Sanbao Zhang Tianyu Wang Yibing Tan Bin Zhou Shanghai Key Laboratory of atmospheric Particle Pollution and Prevention(LAP3) Department of Environmental Science and EngineeringFudan UniversityShanghai 200433China Institute of Eco-Chongming(IEC) No.20 Cuiniao RoadShanghai 202162China Institute of atmospheric {1.s Fudan UniversityShanghai 200433China National Observations and Research Station for Wetland Ecosystems of the Yangtze Estuary Fudan UniversityShanghai 200438China Institute of Digitalized Sustainable Transformation Big Data InstituteFudan UniversityShanghai 200433China

Formaldehyde(HCHO)is considered one of the most abundant gas-phase carbonyl compounds in the atmosphere,which can be directly emitted through transportation ***-Path Differential Optical Absorption Spectroscopy(LP-DOAS)was used to observe HCHO in the river channel of Wusong Wharf in Shanghai,China for the whole year of *** to the impact of ship activity,the annual average HCHO level in the channel is about2.5 times higher than that in the nearby campus *** explain the sources of HCHO under different meteorological conditions,the tracer-pair of CO and O_(x)(NO_(2)+O_(3))was used on the clustered air *** results of the source appointment show that primary,secondary and background account for 24.1.%(3.34±1.1. ppbv),44.78%(6.20±2.04ppbv)and 31.09%(4.31.2.33 ppbv)of the HCHO in the channel when the air masses were from the mixed direction of the city and channel,*** performing background station subtraction at times of high primary HCHO values and resolving the plume peaks,directly emitted HCHO/NO_(2)in the channel environment and plume were determined to be mainly distributed between 0.2 and *** cargo ships with higher sailing speeds or main engine powers tend to have higher HCHO/NO_(2)*** the knowledge of NO_(2)(or NO_(x))emission levels from ships,this study may provide data support for the establishment of HCHO emission factors.

关键词： HCHO LP-DOAS Channel environment Ship emissions

Global Change in Agricultural Flash Drought over the 21.t Century

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Advances in atmospheric {1.s 2024年第2期41卷 209-220,I0002-I0019页

作者： Emily BLACK National Centre for atmospheric {1. Fairbairn House71-75 Clarendon RoadLeedsLS29PHU.K department of Meteorology Brian Hoskins BuildingUniversity of ReadingWhiteknights campusReadingRG66ETU.K.

Agricultural flash droughts are high-impact phenomena, characterized by rapid soil moisture dry down. The ensuing dry conditions can persist for weeks to months, with detrimental effects on natural ecosystems and crop cultivation. Increases in the frequency of these rare events in a future warmer climate would have significant societal impact. This study uses an ensemble of 1. Coupled Model Intercomparison Project(CMIP) models to investigate the projected change in agricultural flash drought during the 21.t century. Comparison across geographical regions and climatic zones indicates that individual events are preceded by anomalously low relative humidity and precipitation, with long-term trends governed by changes in temperature, relative humidity, and soil moisture. As a result of these processes, the frequency of both upperlevel and root-zone flash drought is projected to more than double in the mid-and high latitudes over the 21.t century, with hot spots developing in the temperate regions of Europe, and humid regions of South America, Europe, and southern Africa.

关键词： flash drought climate change soil moisture agricultural drought CMIP