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Self-consistent assessment of Li^(+) ion cathodes:Theory ***

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Journal of Energy Chemistry 2021年第8期30卷 229-241,I0006页

作者： Hongjie xu Weidong Xiao zhuo Wang Junhua Hu Guosheng Shao School of Materials Science and Engineering Zhengzhou UniversityZhengzhou 450001China Centre for International Cooperation on Designer Low-carbon&Environmental Materials(CDLCEM) Zhengzhou UniversityZhengzhou 450001China Zhengzhou Materials Genome Institute(ZMGI) Zhengzhou 450100China

Transition metal oxide cathodes such as layered Li Co O_(2),spinel Li Mn_(2)O_(4) and olivine Li Fe PO4 have been commercialized for several decades and widely used in the rechargeable Li-ion batteries(LIBs).While great theoretical efforts have been made using the density functional theory(DFT)method,leading to insightful understanding covering materials stability and functional properties,the lack of consistency in choices of functionals and/or convergence criteria makes it somewhat difficult to compare *** is therefore highly useful to assess these established systems towards self-consistency,thus offering a reliable working basis for theoretical formulation of novel *** in this work,we have carried out systematic DFT calculations on the basis of recently established framework covering both thermodynamic stability,functional properties and associated *** have been made in selfconsistent selection of exchange-correlation(XC)functionals in terms of dependable accuracy with affordable computational cost,which is essential for high-throughput first-principles *** outcome of the current work on three established cathode systems is in very good agreement with experimental data,and the methodology is to provide a solid basis for designing novel cathode materials without using costing non-local exchange-correlation functionals for structure-energy calculations.

关键词： Li-ion batteries Intercalation-type oxide cathodes Ab initio approaches Self-consistency Density functional theory

The function-oriented precursor selection for the preparation of carbon dots

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Nano Research 2023年第8期16卷 11221-11249页

作者： Yalan xu Chan Wang Huan zhuo Dongrun Zhou Qijun Song Key Laboratory of Synthetic and Biological Colloids Ministry of EducationSchool of Chemical and Material EngineeringJiangnan UniversityWuxi 214122China

As a new type of fluorescent nanomaterials,carbon dots(CDs)have exhibited excellent photoluminescence properties with tunable emission and high quantum yields,hence they have attracted an increasing interest in diverse research *** photoluminescence performance of CDs is primarily influenced by their precursors,which directly or indirectly determine the structures and specific functions of the resultant *** this review,we aim to summarize the recent progress on synthesis of CDs using small aliphatic molecules,anilines,polyphenol,polycyclic aromatic hydrocarbons,organic dyes,or biomass as *** associations of the physical and chemical properties of the CDs with their respective precursors are comprehensively investigated,and the potential applications and future development of CDs are discussed in *** is hoped that this review will open new horizons for CDs preparation by rational selection of the precursors from the vastly available carbon sources and the critical comments presented,here could inspire and guide future research in the design of multifunctional CDs.

关键词： carbon dots precursors photoluminescence fluorophore sensing imaging

Numerical Forecasting of Icing on Structural Components of Offshore Platforms in Polar Regions

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China Ocean Engineering 2021年第4期35卷 588-597页

作者： BAI xu SHEN Jie xuE Yan-zhuo SHU Yuan-chao School of Naval Architecture&Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China College of Shipbuilding Engineering Harbin Engineering UniversityHarbin 150001China

The Polar Regions are rich in natural resources but experience an extremely cold *** surfaces of offshore platforms operating in the Polar Regions are prone to *** develop solutions to this problem of surface icing,the influence of both the liquid water concentration of the surrounding atmosphere and the average water droplet diameter on the formation of ice on two major structural components of offshore platforms was analyzed using a combination of Fluent and *** showed that at a wind speed of 7 m/s,as the concentration of liquid water in the air increases from 0.05 to 0.25 g/m3,the amount and thickness of the icing on the surfaces of the two structural components increase *** a wind speed of 7 m/s and when the size of the average water droplet diameter is 20–30(30–35)μm,as the average water droplet diameter increases,the amount and thickness of the icing on the surfaces of the two structural components increase(decrease)gradually.

关键词： offshore platform in cold regions icing numerical analysis icing thermodynamic model icing calculation process

Multi model forecast biases of the diurnal variations of intense rainfall in the Beijing-Tianjin-Hebei region

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Science China Earth Sciences 2022年第8期65卷 1490-1509页

作者： Qi ZHONG zhuo sun Haoming CHEN Jiangbo LI Lili SHEN China Meteorological Administration Training Center Beijing100081China Hebei Meteorological Observatory Shijiazhuang050020China Chinese Academy of Meteorological Sciences Beijing100081China

Forecasts of the intense rainfall events are important for the disaster prevention and reduction in the Beijing-TianjinHebei region(BTHR). What are the common biases in the forecasts of intense rainfall in the current operational numerical models? What are the possible causes of model bias? In this study, intense rainfall events in the BTHR were categorized into two types: those mainly due to strong synoptic forcings(SSF) and those with weak synoptic forcings(WSF). The results showed that,the numerical forecasts tend to overestimate the frequency of intense rainfall events but underestimate the rainfall intensity. Of these, the overestimation of precipitation frequency mainly appeared in the mountainous areas in the afternoon. Compared with global models, high-resolution mesoscale models showed a notable improvement in forecasting the afternoon intense rainfall,while they all have an obvious bias in forecasting the nighttime rainfall. For the WSF type, both global model and mesoscale model have a low forecast skill, with large biases in subdaily propagation feature. The possible causes are related to a poor performance of the model in reproducing the local thermodynamical circulations and the dynamical processes in the planetary boundary layer. So, the biases in forecasting the WSF type intense rainfall showed notable features of nonlinearity, which made it really challenging to understand their physical processes and to improve the associated forecasts.

关键词： The Beijing-Tianjin-Hebei region Diurnal variations of precipitation Operational numerical forecast Bias feature Local circulations

A microextraction approach for rapid extraction and separation of Mn(Ⅱ) and Co(Ⅱ) using saponified D2EHPA system

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Frontiers of Chemical Science and Engineering 2022年第6期16卷 963-972页

作者： Yiwei Zhou Chen zhuo Jinpei Huang Haipeng Liu Jianhong xu The State Key Laboratory of Chemical Engineering Department of Chemical EngineeringTsinghua UniversityBeijing 100084China

In this paper,we proposed a microextraction approach for the extraction and separation of Mn(Ⅱ)and Co(Ⅱ)from sulfate solution simulating leachate of spent lithium-ion battery cathode materials using saponified di-(2-ethylhexyl)phosphoric acid *** effects of the following operational variables were investigated:equilibrium pH,tri-«-butyl phosphate concentration,saponification rate,two-phase ratio and residence *** results showcased that the microextractor can reach the extraction equilibrium within 20 s,thereby greatly reducing necessary extraction time comparing to that of conventional *** volumetric mass transfer coefficient showed 8-21 times larger than that of batch *** the help of microextractor,95%of Mn(Ⅱ)was extracted with a single theoretical stage at a chosen two-phase ratio of 3:1,and the separation factor β_(Mn/Co) was as large as *** the subsequent stripping step,more than 99%of manganese from loaded phase was easily stripped under optimal *** microextraction approach greatly enhances the mass transfer while enabling a continuous and controllable extraction process within a simple structure *** extracting spent electrode material with microextractors,the comprehensive recovery of mangenese can reach 96%.The microextraction approach has a good applicability in the spent lithium-ion battery cathode materials recycling at both bench and industrial scales.

关键词： extraction equilibrium mass transfer coeffi-cient microextraction multicomponent extraction di-(2-ethylhexyl)phosphoric acid

Response and stabilization of a two-stage axial flow compressor restricted by rotating inlet distortion

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Chinese Journal of Aeronautics 2021年第9期34卷 72-82页

作者： Jia LI xu DONG Dakun sun Ruize xu Xiaofeng sun Fluid and Acoustic Engineering Laboratory School of Energy and Power EngineeringBeihang UniversityBeijing 100083China

This paper considers effects of Rotating Inlet Distortion(RID)on a two-stage axial compressor and the stabilization effects of a casing treatment subjected to the considered *** multispool engines,the downstream compressor suffers a RID when the upstream fan/compressor is in rotating stall.A controlled rotating sectional screen upstream of the compressor was adopted to generate the RID in different intensities,and co-or counter spinning direction compared with the *** response of the compressor to inlet distortion was interpreted as the changes of stall *** show that there are two peaks for the stall margin degradation where the distortion screen rotates near 20%and 70%of the rotor’s rotational frequency,*** on the measurements taken during the pre-stall process,it is suggested that the two frequencies are associated with the eigen frequencies of the ***,the first is associated with a stall precursor that is suspected as an initial disturbance existing in compressor and the second is related to a spike-type stall *** last,a kind of Stall Precursor-Suppressed(SPS)casing treatment was applied to enhance the compressor stability in RID *** result indicates that the stall margin is improved by 6%at an average level and there is nearly no efficiency loss caused by the application of such casing treatment.

关键词： Axial compressors Casing treatment Inlet distortion Stall margin Stall precursor

Continuous advantage learning for minimum-time trajectory planning of autonomous vehicles

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Science China(Information Sciences) 2024年第7期67卷 285-294页

作者： zhuo LI Weiran WU Jialin WANG Gang WANG Jian sun School of Automation Beijing Institute of Technology Beijing Institute of Technology Chongqing Innovation Center China Academy of Launch Vehicle Technology Intelligent Game and Decision Laboratory

This paper investigates the minimum-time trajectory planning problem of an autonomous vehicle. To deal with unknown and uncertain dynamics of the vehicle, the trajectory planning problem is modeled as a Markov decision process with a continuous action space. To solve it, we propose a continuous advantage learning(CAL) algorithm based on the advantage-value equation, and adopt a stochastic policy in the form of multivariate Gaussian distribution to encourage exploration. A shared actor-critic architecture is designed to simultaneously approximate the stochastic policy and the value function, which greatly reduces the computation burden compared to general actor-critic methods. Moreover, the shared actor-critic is updated with a loss function built as mean square consistency error of the advantage-value equation, and the update step is performed several times at each time step to improve data efficiency. Simulations validate the effectiveness of the proposed CAL algorithm and its better performance than the soft actor-critic algorithm.

关键词： trajectory planning continuous advantage learning stochastic policy shared actor-critic

High-resolution swath bathymetry using MIMO sonar system

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Journal of Systems Engineering and Electronics 2014年第5期25卷 761-768页

作者： Xionghou Liu Chao sun Jie zhuo Feng Yi Zongwei Liu Institute of Acoustic Engineering Northwestern Polytechnical University

For increasing the cross-track resolution, the multiple input multiple output （MIMO） technique is introduced into the swath bathymetry system and a new swath bathymetry approach using MIMO sonar is proposed. The MIMO sonar is composed of two parallel transmitting uniform linear arrays （ULAs） and a receiving ULA which is perpendicular to the former. The spacing between the two transmitting ULAs is equal to the product of the receiving sensor number and the receiving inter-sensor spacing. Furthermore, two narrowband linear frequency modulation （LFM） pulses, sharing the same frequency band but with opposite modulation slopes, are used as transmitting waveforms of the two transmitting ULAs. With such an array layout and transmitting signals, the MIMO sonar can sound a swath with the cross-track resolution doubling that of the traditional multibeam sonar using a Mills cross array. Numerical examples are provided to verify the effectiveness of the proposed approach.

关键词： bathymetry multibeam sonar multiple input multipleoutput (MIMO) sonar waveform diversity.

Synthesis of an Interrupted AST-Type Zeolitic Imidazolate Framework

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Chinese Journal of Chemistry 2020年第5期38卷 449-452页

作者： Yayong sun Chao zhuo Fei Wang Jian Zhang State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhouFujian 35002China

Presented here is a new interrupted AST-type zeolitic imidazolate framework,Zn5(OH)(dmbim)9(H2O)·4(DMF)(1)with cub and interrupted ast cages,which exhibits permanent porosity,high hydrophobicity and strong solid-state photoluminescent *** importantly,structural ordered DMF molecules are firmly confined in the-ast cage by strong host-guest interactions.

关键词： properties. porosity ordered