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Loading capacity and emulsification phenomena of HREE extraction by dialkylphosphinic acids with different β,γ,δ-substituents

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Journal of Rare Earths 2024年第1期42卷 191-199,I0007页

作者： Junlian Wang Guodong xu Wen xu Jianguo Cui Yufu Chen Ziyong Chang School of Civil and Resource Engineering University of Science and Technology BeijingBeijing100083China Key Laboratory of Ministry of Education for Efficient Mining and Safety of Metal Mines Beijing100083China State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization Baotou Research Institute of Rare EarthsBaotou014030China

The relationship between dialkylphosphinic acid structure and their loading capacity for HREEs and emulsification phenomena has rarely been *** this paper,we took Lu extraction as an example to study the effect of β,γ,δ-substituents of dialkylphosphinic acids on their loading capacity and anti-emulsification performance for *** discuss conveniently,the dialkylphosphinic acids were classified into two groups:β-substituent group(P208,INET-1,P218,USTB-1 and P227)and γ,δ-substituent group(P218,P2132 and Cyanex 272).For β-substituent group extractants,their loading capacities are in the order P208(299.7 mg/L)≈INET-1(299.5 mg/L)>P218(270.8 mg/L)>>USTB-1(163.1 mg/L)>P227(151.4 mg/L),while their anti-emulsification/gelation performances are just in the opposite order P227>USTB-1>P218>P208≈INET-1 under the studied *** γ,δ-substituent group extractants,their loading capacities are in the order P218(270.8 mg/L)>P2132(192.3 mg/L)>Cyanex272(131.7 mg/L),while the anti-emulsification performance of P218 is better than those of P2132 and Cyanex *** loading capacity data given in the parentheses are obtained through repeatedly extracting Lu from ~4×10^(-4)mol/L of Lu aqueous feed solution with initial pH of 2.40 by 0.01 mol/L extractant at phase ratio A/O of 1:1.

关键词： Heavy rare earth element Dialkylphosphinic acid Extraction Loading capacity Emulsification

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CO2-Induced Modulation of Si-O Bonds for Low Temperature Plastic Deformation of Amorphous Silica Nanoparticles with Enhanced Photoluminescence

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Energy & Environmental Materials 2024年第4期7卷 404-412页

作者： Kang Huang Wenzhuo Wu Song xu Pengfei Yan Zhongming Wei Qun xu Henan Institute of Advanced Technology Zhengzhou University College of Materials Science and Engineering Zhengzhou University State Key Laboratory of Superlattices and Microstructures Institute of Semiconductors Chinese Academy of Sciences

Modulation of Si-O bonds under mild conditions has been a challenging issue in the field of material science,which is critical to manufacture highperformance silica-based optical and photonic ***,we introduce a nondestructive technique to achieve Si-O bond rearrangement,leading to plastic deformation and photoluminescence enhancement of amorphous silica nanoparticles using supercritical carbon dioxides in EtOH/H2O solution under mild temperature.

关键词： amorphous silica anisotropic stress photoluminescence plastic deformation supercritical CO2

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Enhanced photocatalytic hydrogen production from Co-MOF/CN by nitrogen and sulfur co-doped coal-based carbon quantum dots

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Journal of Rare Earths 2024年第5期42卷 838-850,I0002页

作者： Shiyong xu Mei Li Yijun Wang Caiyun Gao Rongsheng xu Zhiliang jin School of Chemistry and Chemical Engineering North Minzu UniversityYinchuan750021China Ningxia Key Laboratory of Solar Chemical Conversion Technology.North Minzu University.Yinchuan 750021China State Key Laboratory of National Ethnic Affairs Commission Chemical Technology.North Minzu University Yinchuan750021China

A novel composite photocatalyst for photocatalytic decomposition of water for hydrogen evolution was successfully synthesized by in-situ growth of nitrogen and sulfur co-doped coal-based carbon quantum dots(NSCQDs)nanoparticles on the surface of sheet cobalt-based metal-organic framework(Co-MOF)and graphitic carbon nitride(g-C_(3)N_(4),CN).The structure and properties of the obtained catalysts were systematically *** effectively broaden the absorption of Co-MOF and CN in the visible *** new composite photocatalyst has high hydrogen production activity and the hydrogen production rate reaches 6254μmol/(g·h)at pH=*** the same time,NSCQDs synergy Co-MOF/CN composites have good *** four cycles of hydrogen production,the performance remains relatively *** tran sient photocurrent response and Nyquist plot experimental results further demonstrate the improvement of carrier separation efficiency in composite *** semiconductor type(n-type semico nductor)of the single-phase catalyst was determined by the Mott-Schottky test,and the band structure was *** conductive and valence bands of CN are-0.99 and 1.72 eV,respectively,and the conduction and valence bands of Co-MOF are-1.85 and 1.33 eV,*** e mechanism of the photocatalytic reaction can be inferred,that is,Z-type heterojunction is formed between CN an d Co-MOF,and NSCQDs was used as cocatalyst.

关键词： Nitrogen and sulfur co-doped Coal-based carbon quantum dots Co-MOF CN Photocatalytic hydrogen evolution Rare earths

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Quantitative Analysis of Frosting Characteristics on the Drip Tray of A Cryogenic Valve for LNG Ships

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China Ocean Engineering 2024年第4期38卷 572-585页

作者： BAI xu CHEN Guan-yu DU Yue xu Cao CHEN Jia-jing School of Naval Architecture&Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China

Cryogenic valves play a crucial role in the production and transportation of liquefied natural gas(LNG),and are primarily responsible for efficiently controlling the inflow and outflow of LNG and regulating ***,due to their operation in low-temperature and high-humidity environments,crucial components such as drip trays are susceptible to frosting,which may lead to LNG leakage,thereby causing severe safety *** this study,the user-defined function(UDF)is employed to redevelop Fluent,which integrates the frost growth model with the Eulerian multiphase flow model,to conduct a quantitative analysis of frosting on drip trays of cryogenic *** effects of environmental parameters,such as wind speed,ambient temperature,air humidity,and cold surface temperature on the growth of the frost layer were *** study reveals a limiting wind speed between 1 m/s and 2 m/*** reaching this limit speed,the growth of the frost layer reaches its maximum,and further increases in the wind speed have no significant effect on the growth of the frost ***,the influence of the change in the flow field on droplet impingement and freezing during the growth of the frost layer is considered through the coupling method of the kinematic characteristics of water droplets and the collection coefficient of water *** study identifies the influence of different parameters on the droplet impact efficiency,leading to the modification of the frost layer on the drip tray.

关键词： LNG carrier drip tray frost effective impact coefficient

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SEMI-IMPLICIT SPECTRAL DEFERRED CORRECTION METHODS BASED ON SECOND-ORDER TIME INTEGRATION SCHEMES FOR NONLINEAR PDES

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Journal of Computational Mathematics 2024年第1期42卷 111-133页

作者： Ruihan Guo Yan xu School of Mathematics and Statistics Zhengzhou UniversityZhengzhou 450001China School of Mathematical Sciences University of Science and Technology of ChinaHefei 230026China

In[20],a semi-implicit spectral deferred correction(SDC)method was proposed,which is efficient for highly nonlinear partial differential equations(PDEs).The semi-implicit SDC method in[20]is based on first-order time integration methods,which are corrected iteratively,with the order of accuracy increased by one for each additional *** this paper,we will develop a class of semi-implicit SDC methods,which are based on second-order time integration methods and the order of accuracy are increased by two for each additional *** spatial discretization,we employ the local discontinuous Galerkin(LDG)method to arrive at fully-discrete schemes,which are high-order accurate in both space and *** experiments are presented to demonstrate the accuracy,efficiency and robustness of the proposed semi-implicit SDC methods for solving complex nonlinear PDEs.

关键词： Spectral deferred correction method Nonlinear PDEs Local discontinuous Galerkin method Second-order scheme

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Experimental investigation on the permeability of gap-graded soil due to horizontal suffusion considering boundary effect

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第3期16卷 1072-1084页

作者： xuwei Wang Yeshuang xu State Key Laboratory of Ocean Engineering School of Naval ArchitectureOceanand Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Shanghai Key Laboratory for Digital Maintenance of Buildings and Infrastructure Department of Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China

The boundary condition is a crucial factor affecting the permeability variation due to *** experimental investigation on the permeability of gap-graded soil due to horizontal suffusion considering the boundary effect is conducted,where the hydraulic head difference(DH)varies,and the boundary includes non-loss and soil-loss *** samples are filled into seven soil storerooms connected in *** evaluation,the variation in content of fine sand(ΔR_(f))and the hydraulic conductivity of soils in each storeroom(C_(i))are *** the non-loss test,the soil sample filling area is divided into runoff,transited,and accumulated areas according to the negative or positive ΔR_(f) values.ΔR_(f) increases from negative to positive along the seepage path,and Ci decreases from runoff area to transited area and then rebounds in accumulated *** the soil-loss test,all soil sample filling areas belong to the runoff area,where the gentle-loss,strengthened-loss,and alleviated-loss parts are further divided.ΔR_(f) decreases from the gentle-loss part to the strengthened-loss part and then rebounds in the alleviated-loss part,and C_(i) increases and then decreases along the seepage *** relationship between ΔR_(f) and Ci is different with the boundary *** exponentially decreases with ΔR_(f) in the non-loss test and increases with ΔR_(f) generally in the soil-loss test.

关键词： Suffusion Permeability Experimental investigation Boundary effect Horizontal seepage

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Model-free method for LQ mean-field social control problems with one-dimensional state space

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Control Theory and Technology 2024年第3期22卷 479-486页

作者： Zhenhui xu Tielong Shen School of Engineering Tokyo Institute of TechnologyTokyo 152-8550Japan Department of Engineering and Applied Sciences Sophia UniversityTokyo 102-8554Japan

This paper presents a novel model-free method to solve linear quadratic(LQ)mean-field control problems with one-dimensional state space and multiplicative *** focus is on the infinite horizon LQ setting,where the conditions for solution either stabilization or optimization can be formulated as two algebraic Riccati equations(AREs).The proposed approach leverages the integral reinforcement learning technique to iteratively solve the drift-coefficient-dependent stochastic ARE(SARE)and other indefinite ARE,without requiring knowledge of the system dynamics.A numerical example is given to demonstrate the effectiveness of the proposed algorithm.

关键词： Mean-field control Social optima Infinite horizon Reinforcement learning

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Periodic Variation Studies of the Two Short Period W UMa-type Eclipsing Binaries: LX Lyn and V0853 Aur

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Research in Astronomy and Astrophysics 2024年第1期24卷 273-284页

作者： xu Zhang Bin Zhang School of Physics and Electronic Science Guizhou Normal UniversityGuiyang 550001China Guizhou Provincial Key Laboratory of Radio Astronomy and Data Processing Guizhou Normal UniversityGuiyang 550025China

In this paper,new light curves(LCs) of contact eclipsing binary(CEB) systems LX Lyn and V0853 Aur are presented and analyzed by using the 2015 version of the Wilson-Devinney(W-D) *** order to explain their asymmetric LCs,cool starspots on the components were *** is suggested that their fill-out degrees are f=12.0%(LX Lyn) and f=26.3%(V0853 Aur).At the same time,we found that LX Lyn is a W-type eclipsing binary(EB) with an orbital inclination of i=84°.88 and a mass ratio of q=2.31.V0853 Aur is also a W-type CEB with a mass ratio of q=2.77 and an orbital inclination of i= 79°.*** on all available times of light minimum,their orbital period changes are studied by using the O-C *** O-C diagram of LX Lyn reveals a cyclic oscillation with a period of about 14.84 yr and an amplitude of 0.0019 days,which can be explained by the light-travel time effect(LTTE) due to the presence of a third body with a minimum mass of0.06M_⊙.For V0853 Aur,it is discovered that the O-C diagram of the system also shows a cyclic oscillation with a period of 9.64 yr and an amplitude of 0.03365 *** cyclic oscillation of V0853 Aur can be attributed to the LTTE by means of a third body with a mass no less than 3.77M_⊙.The third body may play an important role in the formation and evolution of these systems.

关键词： stars:activity (stars:)binaries(including multiple):close (stars:)binaries:eclipsing (stars:)brown dwarfs stars:evolution stars:formation

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MODIFIED STOCHASTIC EXTRAGRADIENT METHODS FOR STOCHASTIC VARIATIONAL INEQUALITY

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Journal of Computational Mathematics 2024年第2期42卷 390-414页

作者： Ling Zhang Lingling xu School of Management and Economic Beijing Institute of TechnologyBeijing 100081China School of Mathematical Sciences Nanjing Normal UniversityNanjing 210023China School of Mathematical Sciences and Jiangsu Key Laboratory for NSLSCS Nanjing Normal UniversityNanjing 210023China

In this paper,we consider two kinds of extragradient methods to solve the pseudo-monotone stochastic variational inequality ***,we present the modified stochastic extragradient method with constant step-size(MSEGMC)and prove the convergence of *** the strong pseudo-monotone operator and the exponentially growing sample sequences,we establish the R-linear convergence rate in terms of the mean natural residual and the oracle complexity O(1/ǫ).Second,we propose a modified stochastic extragradient method with adaptive step-size(MSEGMA).In addition,the step-size of MSEGMA does not depend on the Lipschitz constant and without any line-search ***,we use some numerical experiments to verify the effectiveness of the two algorithms.

关键词： Stochastic variational inequality Pseudo-monotone Modified stochastic ex-tragradient methods Adaptive step-size

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Evidence-based practices in sustainable travel behavior intervention: A knowledge graph-based systematic review

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Journal of Traffic and Transportation Engineering(English Edition) 2024年第2期11卷 293-311页

作者： Jian Li Chenjie xu Key Laboratory of Road and Traffic Engineering of the Ministry of Education College of Transportation EngineeringTongji UniversityShanghai 201804China

Sustainable travel behavior intervention is an essential strategy to promote the development of urban *** interventions offer personalized strategies based on certain scenario and participants to promote its effectiveness over hard travel ***,personalized strategies may also bring about difficulties to identify the actual effect of the ***,based on current practice,to make full use of travel behavior interventions,it is necessary to construct a unified methodological evidencebased framework to assess the reliability and effectiveness of travel behavior intervention *** response to these issues,we applied evidence-based knowledge graph to the field of sustainable travel behavior interventions to help decision supporters design sustainable travel behavior interventions wisely and in turn avoid excessive use of hard travel *** introduced concept of evidence-based practice to conduct a systematic analysis concerning reliability and validity of current full volume empirical studies by dimensions of scenarios,types of interventions and *** addition,we took advantage of high extensivity and integrability of knowledge graph to organize evidence-based related *** of the systematic analysis shows that in terms of reliability of evidence,school intervention is the best scenario,knowledge incentive is the best intervention type and promoting public transit and walking proportion are the best ***,the reliability of interventions in workplace,belonging to reward and threat along with aiming at changing travel patterns generally and lowering travel carbon emission need to be *** the study,various research prospects are raised to promote evidence quality in the field of travel behavior intervention *** a pioneer study,our research contributes to the field of urban transportation in introducing concepts of evidence-based practice and enabling optimization and

关键词： Evidence-based decision-making Evidence assessment Knowledge graph Travel behavior intervention Sustainable travel

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