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Implementation of a One-Dimensional Enthalpy Sea-Ice Model in a Simple Pycnocline Prediction Model for Sea-Ice Data Assimilation Studies

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Advances in Atmospheric Sciences 2016年第2期33卷 193-207页

作者： Xinrong WU Shaoqing ZHANG Zhengyu Liu Key Laboratory of Marine Environmental Information Technology State Oceanic AdministrationNational Marine Data and Information Service Geophysical Fluid Dynamics Laboratory National Oceanic and Atmospheric AdministrationPrinceton University Center for Climate Research and Dept.Atmospheric and Oceanic Sciences University of Wisconsin-Madison Laboratory of Ocean–Atmosphere Studies Peking University

To further explore enthalpy-based sea-ice assimilation, a one-dimensional （1D） enthalpy sea-ice model is implemented into a simple pycnocline prediction model. The 1D enthalpy sea-ice model includes the physical processes such as brine expulsion, flushing, and salt diffusion. After being coupled with the atmosphere and ocean components, the enthalpy sea-ice model can be integrated stably and serves as an important modulator of model variability. Results from a twin experiment show that the sea-ice data assimilation in the enthalpy space can produce smaller root-mean-square errors of model variables than the traditional scheme that assimilates the observations of ice concentration, especially for slow-varying states. This study provides some insights into the improvement of sea-ice data assimilation in a coupled general circulation model.

关键词： sea ice enthalpy coupled model data assimilation ensemble Kalman filter

Autonomous mission reconstruction during the ascending flight of launch vehicles under typical propulsion system failures

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Chinese Journal of Aeronautics 2022年第6期35卷 211-225页

作者： zhengyu SONG Yin liu Yong HE Cong WANG China Academy of Launch Vehicle Technology Beijing 100076China Beijing Institute of Astronautical Systems Engineering Beijing 100076China Beijing Aerospace Automatic Control Institute Beijing 100854China

In recent years, Chinese Long March(LM) launchers have experienced several launch failures, most of which occurred in their propulsion systems, and this paper studies Autonomous Mission Reconstruction(AMRC) technology to alleviate losses due to these failures. The status of the techniques related to AMRC, including trajectory and mission planning, guidance methods,and fault tolerant technologies, are reviewed, and their features are compared, which reflect the challenges faced by AMRC technology. After a brief introduction about the failure modes of engines that can occur during flight, and the fundamentals of trajectory planning and joint optimization of the target orbit and flight path, an AMRC algorithm is proposed for geostationary transfer orbit launch missions. The algorithm evaluates the residual performance onboard, and plans new objectives and corresponding flight path by iterative guidance mode or segmented state triggered optimization methods in real-time. Three failure scenarios that have occurred during previous LM missions are simulated to check the robustness of the algorithm: imminent explosion risk of the boosters’ engines, thrust drop during the first stage of flight, and being unable to start the engine during the second stage. The payloads would fall from space according to the current design under these conditions, but they were saved with the AMRC algorithm in the simulations, which allowed the rocket to get into the target orbit as intended or the payloads were deployed in other orbits without crashing. Although spaceflight can be very unforgiving, the AMRC algorithm has the potential to avoid the total loss of a launch mission when faced with these kinds of typical failures.

关键词： Autonomous mission reconstruction Closed-loop guidance State triggered indices Rescue orbits Launch vehicles

Impact of the Time Scale of Model Sensitivity Response on Coupled Model Parameter Estimation

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Advances in Atmospheric Sciences 2017年第11期34卷 1346-1357页

作者： chang liu shaoqing zhang shan li Zhengyu Liu college of automation harbin engineering universityHarbin 150001China noaa gfdl–university of wisconsin-madison joint visit program NJ 08540USA physical oceanography laboratory/cimst ocean university of china and qingdao national laboratory for marine science and technologyqingdao 266003China international center for climate and environment sciences institute of atmospheric physicschinese academy of sciencesBeijing 100029China laboratory for climate and ocean–atmosphere studies(la coas) department of atmospheric and oceanic sciencesschool of physicspeking universityBeijing 100871China center for climate research and department of atmospheric and oceanic sciences university of wisconsin-madisonmadisonWI 53706USA

That a model has sensitivity responses to parameter uncertainties is a key concept in implementing model parameter es- timation using filtering theory and methodology. Depending on the nature of associated physics and characteristic variability of the fluid in a coupled system, the response time scales of a model to parameters can be different, from hourly to decadal. Unlike state estimation, where the update frequency is usually linked with observational frequency, the update frequency for parameter estimation must be associated with the time scale of the model sensitivity response to the parameter being esti- mated. Here, with a simple coupled model, the impact of model sensitivity response time scales on coupled model parameter estimation is studied. The model includes characteristic synoptic to decadal scales by coupling a long-term varying deep ocean with a slow-varying upper ocean forced by a chaotic atmosphere. Results show that, using the update frequency deter- mined by the model sensitivity response time scale, both the reliability and quality of parameter estimation can be improved significantly, and thus the estimated parameters make the model more consistent with the observation. These simple model results provide a guideline for when real observations are used to optimize the parameters in a coupled general circulation model for improving climate analysis and prediction initialization.

关键词： coupled model parameter estimation time scale of model sensitivity

Numerical study on matching conditions of Langmuir parametric instability and the formation of Langmuir turbulence in ionospheric heating

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Earth and Planetary Physics 2022年第5期6卷 474-486页

作者： MoRan liu Chen Zhou Ting Feng Xiang Wang zhengyu Zhao Department of Space Physics School of Electronic InformationWuhan UniversityWuhan 430072China School of Computer Science and Information Engineering Hubei UniversityWuhan 430011China

Parametric decay instability(PDI)is an important process in ionospheric heating.This paper focuses on the frequency and wavevector matching condition in the initial PDI process,the subsequent cascade stage,and the generation of strong Langmuir turbulence.A more general numerical model is established based on Maxwell equations and plasma dynamic equations by coupling highfrequency electromagnetic waves to low-frequency waves via ponderomotive force.The primary PDI,cascade process,and strong Langmuir turbulence are excited in the simulation.The matching condition in the initial PDI stage and cascade process is verified.The result indicates that the cascade ion acoustic wave may induce or accelerate the formation of cavitons and lead to the wavenumber spectrum being more enhanced at 2k_(L)(where k_(L) is the primary Langmuir wavenumber).The wavenumber spectra develop from discrete to continuous spectra,which is attributed to the caviton collapse and strong Langmuir turbulence.

关键词： ionospheric electromagnetic propagation parametric decay instability cascade Langmuir turbulence

Enhancing XRF sensor-based sorting of porphyritic copper ore using particle swarm optimization-support vector machine(PSO-SVM)algorithm

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International Journal of Mining Science and Technology 2024年第4期34卷 545-556页

作者： Zhengyu Liu Jue Kou Zengxin Yan Peilong Wang Chang liu Chunbao Sun Anlin Shao Bern Klein School of Civil and Resources Engineering University of Science and TechnologyBeijing 100083China Institute of Minerals Research University of Science and TechnologyBeijing 100083China State Key Laboratory of Mineral Processing Beijing 102628China Ansteel Group Mining Co.Ltd. Anshan 114000China Norman B.Keevil Institute of Mining Engineering University of British ColumbiaVancouverBC V6T 1Z4Canada

X-ray fluorescence(XRF)sensor-based ore sorting enables efficient beneficiation of heterogeneous ores,while intraparticle heterogeneity can cause significant grade detection errors,leading to misclassifications and hindering widespread technology adoption.Accurate classification models are crucial to determine if actual grade exceeds the sorting threshold using localized XRF signals.Previous studies mainly used linear regression(LR)algorithms including simple linear regression(SLR),multivariable linear regression(MLR),and multivariable linear regression with interaction(MLRI)but often fell short attaining satisfactory results.This study employed the particle swarm optimization support vector machine(PSO-SVM)algorithm for sorting porphyritic copper ore pebble.Lab-scale results showed PSO-SVM out-performed LR and raw data(RD)models and the significant interaction effects among input features was observed.Despite poor input data quality,PSO-SVM demonstrated exceptional capabilities.Lab-scale sorting achieved 93.0%accuracy,0.24%grade increase,84.94%recovery rate,57.02%discard rate,and a remarkable 39.62 yuan/t net smelter return(NSR)increase compared to no sorting.These improvements were achieved by the PSO-SVM model with optimized input combinations and highest data quality(T=10,T is XRF testing times).The unsuitability of LR methods for XRF sensor-based sorting of investigated sample is illustrated.Input element selection and mineral association analysis elucidate element importance and influence mechanisms.

关键词： XRF sensor-based sorting PSO-SVM algorithm Copper ore pebble Receiver operating curve(ROC) Net smelter return(NSR)

In vitro and in vivo degradation behavior of poly(trimethylene carbonate-co-D,L-lactic acid)copolymer

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Regenerative Biomaterials 2017年第4期4卷 207-213页

作者： zhengyu Ma Yi Wu Jing Wang Changsheng liu Engineering Research Center for Biomedical Materials of Ministry of Education School of Materials Science and EngineeeringEast China University of Science and TechnologyShanghai 200237People’s Republic of China The State Key Laboratory of Bioreactor Engineering School of Materials Science and EngineeringEast China University of Science and TechnologyShanghai 200237People’s Republic of China Key Laboratory for Ultrafine Materials of Ministry of Education School of Materials Science and EngineeringEast China University of Science and TechnologyShanghai 200237People’s Republic of China

We present P(TMC-co-DLLA)copolymer with the molar ratio of TMC:DLLA紏15:85 was used to systematic study of in vivo and in vitro degradation behaviors.Dense homogeneous copolymer specimens were prepared by compression molding method.The in vitro and in vivo degradation were,respectively,performed at simulative body condition and implanted into rat’s subcutaneous condition.Investigations were followed via physicochemical and histological analysis such as SEM,GPC,DSC,FTIR and H&E stain.The results demonstrate that copolymeric material can degrade in phosphate buffer solution(PBS)and in rat’s body,and the in vivo degradation rate is faster.Obvious decline of molecule weight and mass loss has been observed,which led to the attenuation of mechanical strength.Furthermore,apart from the hydrolysis,macrophagocytes took part in the phagocytosis in vivo,indicating that degradation rate could be regulated by the combinational mechanism.It is concluded that P(TMC-co-DLLA)copolymer is a promising candidate for tissue repair.

关键词： P(TMC-co-DLLA) copolymer degradation tissue repair

Influence and mechanism of solar radiation intensity on the interdecadal variability of strong Meiyu events during historical periods

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Science China Earth Sciences 2023年第2期66卷 408-416页

作者： liulin WANG Liang NING Kefan CHEN Mi YAN Jian liu Zhengyu Liu Yanmin QIN Jiao XUE Chuxin LI Key Laboratory for Virtual Geographic Environment Ministry of Education/State Key Laboratory Cultivation Base of Geographical Environment Evolution of Jiangsu Province/Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application/School of GeographyNanjing Normal UniversityNanjing210023China Open Studio for the Simulation of Ocean-Climate-Isotope Pilot National Laboratory for Marine Science and Technology(Qingdao)Qingdao266237China Climate System Research Center Department of GeosciencesUniversity of MassachusettsAmherst01003USA State Key Laboratory of Loess and Quaternary Geology Institute of Earth EnvironmentChinese Academy of SciencesXi’an710061China Department of Geography The Ohio State UniversityColumbusOH43210USA

Most recent studies on Meiyu over the middle and lower reaches of the Yangtze River(MLRYR)have focused on its interannual variability or the mechanism of certain abnormal events.The influence and physical mechanism of solar radiation intensity on the interdecadal frequency of strong Meiyu events over the MLRYR during historical periods were investigated using reconstructed precipitation data,reconstructed solar radiation data,and model simulation data.First,according to the solar radiation intensity,the Ming and Qing Dynasties(1470-1850)were divided into three periods of strong solar radiation and three periods of weak solar radiation.It was found that during the periods of strong solar radiation,the frequency of strong Meiyu events was significantly higher than that during the periods of weak solar radiation in the reconstructed precipitation data and model simulations.Mechanism analyses show that during the periods of strong solar radiation,the Western Pacific Subtropical High(WPSH)is stronger,and the blocking highs over the middle-high-latitudes are also stronger,which is conducive to the continuous convergence of the southward cold air and the northward warm and humid air flow at the MLRYR.Therefore,a circulation spatial pattern conducive to the occurrence of strong Meiyu events is then induced.The probability distributions of precipitation also show that,during periods of strong solar radiation,changes in circulation patterns cause the probability distribution of precipitation to shift significantly to the right,increasing the probability of strong Meiyu events occurring on the right side of the probability distribution.

关键词： Ming Dynasty Historical flood Strong Meiyu events Solar radiation CESM-LME

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Evidence of X-mode heating suppressing O-mode heating

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Earth and Planetary Physics 2020年第6期4卷 588-597页

作者： Ting Feng Chen Zhou Xiang Wang MoRan liu zhengyu Zhao Department of Space Physics School of Electronic InformationWuhan UniversityWuhan 430072China

In this study,we present three experiments carried out at the EISCAT(European Incoherent Scatter Scientific Association)heating facility on October 29 and 30,2015.The results from the first experiment showed overshoot during the O-mode heating period.The second experiment,which used cold-start X-mode heating,showed the generation of parametric decay instability,whereas overshoot was not observed.The third experiment used power-stepped X-mode heating with noticeable O-mode wave leakage.Parametric decay instability and oscillating two-stream instability were generated at the O-mode reflection height without the overshoot effect,which implies suppression of the thermal parametric instability with X-mode heating.We propose that the electron temperature increased because X-mode heating below the upper hybrid height decreased the growth rate of the thermal parametric instability.

关键词： ionospheric heating parametric decay instability thermal parametric instability overshoot suppression

浅析裴罗将军城及其年代——兼论葛逻禄西迁时间

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西域研究 2023年第2期 26-37,170页

作者：刘振玉不详

《新唐书·地理志》记录有“裴罗将军城”,学界通常将其与西辽都城八剌沙衮联系在一起,其建城之源存在争论。本文从时间维度、地理位置相关性等因素分析,认为裴罗将军城应是突骑施黑姓可汗阿多裴罗所建,即阿拉伯地理文献中记录的“突骑... 详细信息

《新唐书·地理志》记录有“裴罗将军城”,学界通常将其与西辽都城八剌沙衮联系在一起,其建城之源存在争论。本文从时间维度、地理位置相关性等因素分析,认为裴罗将军城应是突骑施黑姓可汗阿多裴罗所建,即阿拉伯地理文献中记录的“突骑施汗廷”,其创建时间应不早于753年,至迟到791年葛逻禄西迁时已不再具备存在的条件。文献记载8世纪下半叶葛逻禄西迁楚河流域,但西迁时间学界迄无定论,通过分析当时之政治形势,综合文献记载,特别是九姓回鹘可汗碑中的相关信息,本文认为葛逻禄西迁应发生在791年或其后不久。

关键词：裴罗将军城突骑施葛逻禄西迁北庭之战