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Multifunctional carbon materials from rugose rose for energy storage and water purification

Frontiers of Chemical Science and Engineering 2024年第9期18卷 1-13页

作者： Peng-hui li hui Zhou Wen-Juan Wu Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources Nanjing Forestry UniversityNanjing 210037China College of light Industry and Food Engineering Nanjing Forestry UniversityNanjing 210037China College of Chemical Engineering East China University of Science and TechnologyShanghai 200237China State Key Laboratory of Chemical Engineering Shanghai 200237China

With the advancement of social process,the resource problem is becoming more prominent,biomass materials come into being,and it is becoming more and more important to explore and prepare efficient and multifunctional biomass materials to alleviate the problems of energy storage and water *** this paper,nitrogen-doped hierarchical porous carbon materials(NRRC)were produced by one-step carbonization of withered rose as raw material and melamine as nitrogen source with KOH-activated *** resulting nitrogen-doped porous carbon material had the most abundant pores and the best microspherical graded pore structure,with a specific surface area of up to 1.93 m2·g^(-1.,a pore volume of 0.68 cm3·g^(-1.,and a nitrogen-doped content of 5.52%.Electrochemical tests showed that the maximum specific capacitance of NRRC in the three-electrode system was 346.4 F·g^(-1.(0.5 A·g^(-1.),which was combined with favorable capacitance retention performance and cycling *** NRRC//NRRC symmetric supercapacitors were further assembled,and the maximum energy density of a single device was 23.88 Wh·kg^(-1.,which still maintains excellent capacitance retention and cyclic charging/discharging *** example,the capacitance retention rate was always close to 96.27%with almost negligible capacitance loss after 1.000 consecutive charge/discharge cycles(current density:1. A·g^(-1.).Regardless of the three-electrode or two-electrode system,the super capacitive performance of NRRC porous carbon materials was comparable to the electrochemical performance of many reported biomass porous carbon materials,which showed better energy storage advantages and practical application *** addition,NRRC porous carbon materials had excellent water purification *** dye adsorption test confirmed that NRRC had a high adsorption capacity(491.47 mg·g^(-1.)for methylene *** undoubtedly also showed a potential and promising avenue for high value-added utilization

关键词： rose carbon adsorption electrode material electrochemical performance

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Differences between lower extremity joint running kinetics captured by marker-based and markerless systems were speed dependent

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Journal of Sport and Health Science 2024年第4期13卷 569-578页

作者： hui Tang Barry Munkasy li li Department of Health Sciences and Kinesiology Georgia Southern UniversityStatesboroGA 30458USA Department of Kinesiology and Health Education University of Texas at AustinAustinTX 78712USA

Background:The development of computer vision technology has enabled the use of markerless movement tracking for biomechanical *** research has reported the feasibility of markerless systems in motion analysis but has yet to fully explore their utility for capturing faster movements,such as *** studies using markerless systems in clinical and sports settings are still ***,the present study compared running biomechanics estimated by marker-based and markerless *** running speed not only affects sports performance but is also associated with clinical injury prevention,diagnosis,and rehabilitation,we aimed to investigate the effects of speed on the comparison of estimated lower extremity joint moments and powers between markerless and marker-based technologies during treadmill running as a concurrent validating ***:Kinematic data from marker-based/markerless technologies were collected,along with ground reaction force data,from 1. young adults running on an instrumented treadmill at 3 speeds:2.24 m/s,2.91.m/s,and 3.58 m/s(5.0 miles/h,6.5 miles/h,and 8.0 miles/h).Sagittal plane moments and powers of the hip,knee,and ankle were calculated by inverse dynamic *** series analysis and statistical parametric mapping were used to determine system ***:Compared to the marker-based system,the markerless system estimated increased lower extremity joint kinetics with faster speed during the swing phase in most ***:Despite the promising application of markerless technology in clinical settings,systematic markerless overestimation requires focused *** on segment pose estimations,the centers of mass estimated by markerless technologies were farther away from the relevant distal joint centers,which led to greater joint moments and powers estimates by markerless ***-based *** differences were amplified by running speed.

关键词： Biomechanics Motion capture Gait Statistical parametric mapping

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Higher-order expansions of powered extremes of logarithmic general error distribution

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Applied Mathematics(A Journal of Chinese Universities) 2024年第1期39卷 47-54页

作者： TAN Xiao-feng li li-hui School of Mathematics and Statistics Southwest UniversityChongqing 400715China

In this paper,Let M_(n)denote the maximum of logarithmic general error distribution with parameter v≥***-order expansions for distributions of powered extremes M_(n)^(p)are derived under an optimal choice of normalizing *** is shown that M_(n)^(p),when v=1.converges to the Frechet extreme value distribution at the rate of 1.n,and if v>1.then M_(n)^(p)converges to the Gumbel extreme value distribution at the rate of(loglogn)^(2)=(log n)^(1.1.v).

关键词： logarithmic general error distribution convergence rate higher-order expansion powered ex-treme

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Prescribed-time stabilization and inverse optimal control of stochastic high-order nonlinear systems

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Science China(Information Sciences) 2024年第2期67卷 144-156页

作者： Ran liU hui WANG Wuquan li School of Mathematics and Statistics Science Ludong University

This paper investigates the prescribed-time state-feedback stabilization and prescribed-time inverse optimality problems for stochastic high-order nonlinear systems. First, a time-varying controller is designed by developing scaled quartic Lyapunov functions, which can guarantee that the system has a unique strong solution almost surely on the prescribed interval for any system initial conditions and that the states and the control converge to the origin in a mean-square form within the prescribed time. Then, the controller is redesigned to address the problem of prescribed-time inverse optimal mean-square stabilization. Finally,a concrete example is provided to confirm the efficiency of the proposed design schemes.

关键词： stochastic high-order nonlinear systems prescribed-time stabilization the scaled design inverse optimality

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Effect of tungsten carbide particles on microstructure and mechanical properties of Cu alloy composite bit matrix

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Journal of Iron and Steel Research International 2024年第2期31卷 519-530页

作者： Ding-qian Dong Feng-yuan He Xin-hui Chen hui li Kai-hua Shi hui-wen Xiong Xin Xiang li Zhang College of Mechanical Engineering Sichuan University of Science and EngineeringZigong643000SichuanChina State Key Laboratory of Powder Metallurgy Central South UniversityChangsha410083HunanChina Zigong Cemented Carbide Co. Ltd.Zigong643011SichuanChina Material Corrosion and Protection Key Laboratory of Sichuan Province Sichuan University of Science and EngineeringZigong643000SichuanChina

Copper alloy composite bit matrix was prepared by pressureless vacuum infiltration,using at least one of the three kinds of tungsten carbide particles,for example,irregular cast tungsten carbide,monocrystalline tungsten carbide and sintered reduced tungsten carbide *** effects of powder particle morphology,particle size and mass fraction of tungsten carbide on the microstructure and mechanical properties of copper alloy composite were investigated by means of scanning electron microscopy,X-ray diffraction and abrasive wear test in *** results show that tungsten carbide morphology and particle size have obvious effects on the mechanical properties of copper alloy *** tungsten carbide partially dissolved in the copper alloy binding phase,and layers of Cu_(0.3)W_(0.5)Ni_(0.1.Mn_(0.1.C phase with a thickness of around 8–1.μm were formed on the edge of the cast tungsten *** 45%irregular crushed fine cast tungsten carbide and 1.%monocrystalline cast tungsten carbide were used as the skeleton,satisfactory comprehensive performance of the reinforced copper alloy composite bit matrix was obtained,with the bending strength,impact toughness and hardness reaching 1.48 MPa,4.95 J/cm^(2) and 43.6 HRC,*** main wear mechanism was that the tungsten carbide particles firstly protruded from the friction surface after the copper alloy matrix was worn,and then peeled off from the matrix when further wear occurred.

关键词： Polycrystalline diamond compact Pressureless vacuum infiltration Copper alloy composite bit matrix Microstructure characterization Abrasive wear behavior

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Measurement of acceleration and angular velocity of particles during a 3D silo discharge

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Particuology 2024年第9期92卷 61-71页

作者： Tongtong Mu Yiming li Quan Chen Ran li hui Yang College of Medical Instrument Shanghai University of Medicine and Health SciencesShanghai201318China School of Optical-Electrical and Computer Engineering University of Shanghai for Science and TechnologyShanghai200093China

Accurate measurement of the three-dimensional(3D)movement of discrete particles is crucial for comprehending complex granular rheology in *** this paper,the acceleration and angular velocity of particles in 3D silos are measured by using a spherical detector based on inertial technology and magnetic positioning *** acceleration of particles is the largest in the center of silos,which suggest that the resistance generated by friction and extrusion is the ***,the angular velocity distribution follows lognormal function except for particles near the *** correlation between acceleration and angular velocity is opposite in different flow *** reveals for the first time that the extent to which the resultant force on the particles affects their rotational motion is related to the flow *** results have practical significance for regulating the granular flow pattern and optimizing the structural design of silos.

关键词： Granularflow Silo Angular velocity Acceleration

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Selective hydrodeoxygenation of guaiacol to cyclohexanol using activated hydrochar-supported Ru catalysts

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Frontiers of Chemical Science and Engineering 2024年第5期18卷 13-22页

作者： Kaile li Shijie Yu Qinghai li Yanguo Zhang hui Zhou Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Beijing Key Laboratory of CO_(2) Utilization and Reduction TechnologyDepartment of Energy and Power EngineeringTsinghua UniversityBeijing 100084China Department of Chemical and Biomolecular Engineering National University of SingaporeSingapore117585Singapore

lignin,an abundant aromatic polymer in nature,has received significant attention for its potential in the production of bio-oils and chemicals owing to increased resource availability and environmental *** hydrodeoxygenation of guaiacol,a lignin-derived monomer,can produce cyclohexanol,a nylon precursor,in a carbon-negative and environmentally friendly *** study explored the porous properties and the effects of activation methods on the Ru-based catalyst supported by environmentally friendly and cost-effective *** selective cleavage of C_(ary)-O bonds was achieved under mild conditions(1.0°C,0.2 MPa H_(2),and 4 h),and alkali activation further improved the catalytic *** characterization methods revealedthat hydrothermal treatment and alkali activation relatively contributed to the excellent performance of the catalysts and influenced their porous structure and Ru dispersion.X-ray photoelectron spectroscopy results revealed an increased formation of metallic ruthenium,indicating the effective regulation of interaction between active sites and *** synergistic approach used in this study,involving the valorization of cellulose-derived hydrochar and the selective production of nylon precursors from lignin-derived guaiacol,indicated the comprehensive and sustainable utilization of biomass resources.

关键词： hydrochar guaiacol cyclohexanol activation full-component utilization

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Anomalous response to creep deformation from dislocation density during electrically assisted creep aging

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Rare Metals 2024年第10期43卷 5268-5283页

作者： Chang Zhou li-Hua Zhan Chun-hui liu Ming-hui Huang College of Mechanical and Electrical Engineering Central South University light Alloys Research Institute State Key Laboratory of Precision Manufacturing for Extreme Service PerformanceCentral South University

Adding numerous dislocations into metallic materials before the forming stage significantly enhances their deformability. However, this beneficial effect of dislocation defects may not have a simple monotonic relationship with increased dislocation density during electroplastic deformation. This is due to the complex interactions among the drifting electrons, dislocations and solute atoms. This study explores the effect of diverse initial dislocation densities on creep deformation during electrically aided creep aging of an aluminum–lithium alloy. Surprisingly, we discovered a threshold value for the dislocation density that affects electroplastic creep, i.e., an enhanced effect from dislocations weakens when exceeding this density threshold(an anomalous response to creep). Microstructural data also reveal that such an anomalous response originates mainly from differences in various dislocation density-tailored configurations, which can influence the dislocation motions and precipitation kinetics of the strengthening T1.recipitates under the same action of pulsed currents. This study provides important insights into the dislocation density-mediated electroplastic creep of an aluminum–lithium alloy.

关键词： Al–Cu–li alloy Creep aging Dislocation density Pulsed currents

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Estimation of tunnel axial orientation in the interlayered rock mass using a comprehensive algorithm

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2579-2590页

作者： hui li Weizhong Chen Xianjun Tan State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China

The axial selection of tunnels constructed in the interlayered soft-hard rock mass affects the stability and safety during *** optimization is primarily based on experience or comparison and selection of alternative values under specific geological *** this work,an intelligent optimization framework has been proposed by combining numerical analysis,machine learning(ML)and optimization *** automatic and intelligent numerical analysis process was proposed and coded to reduce redundant manual *** conventional optimization algorithm was developed from two aspects and applied to the hyperparameters estimation of the support vector machine(SVM)model and the axial orientation optimization of the ***,the comprehensive framework was applied to a numerical case study,and the results were compared with those of other *** results of this study indicate that the determination coefficients between the predicted and the numerical stability evaluation indices(STIs)on the training and testing datasets are 0.998 and 0.997,*** a given geological condition,the STI that changes with the axial orientation shows the trend of first decreasing and then increasing,and the optimal tunnel axial orientation is estimated to be 87.This method provides an alternative and quick approach to the overall design of the tunnels.

关键词： Tunnel Building information modeling Design optimization Particle swarm optimization Support vector machine(SVM)

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Machine Learning-based Identification of Contaminated Images in light Curve Data Preprocessing

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Research in Astronomy and Astrophysics 2024年第4期24卷 287-295页

作者： hui li Rong-Wang li Peng Shu Yu-Qiang li Yunnan Observatories Chinese Academy of SciencesKunming 650216China University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Space Object and Debris Observation Chinese Academy of SciencesNanjing 210023China

Attitude is one of the crucial parameters for space objects and plays a vital role in collision prediction and debris *** light curves to determine attitude is the most commonly used *** photometric observations,outliers may exist in the obtained light curves due to various ***,preprocessing is required to remove these outliers to obtain high quality light *** statistical analysis,the reasons leading to outliers can be categorized into two main types:first,the brightness of the object significantly increases due to the passage of a star nearby,referred to as“stellar contamination,”and second,the brightness markedly decreases due to cloudy cover,referred to as“cloudy contamination.”The traditional approach of manually inspecting images for contamination is time-consuming and ***,we propose the utilization of machine learning methods as a *** Neural Networks and SVMs are employed to identify cases of stellar contamination and cloudy contamination,achieving F1.scores of 1.00 and 0.98 on a test set,*** also explore other machine learning methods such as ResNet-1. and light Gradient Boosting Machine,then conduct comparative analyses of the results.

关键词： techniques:image processing methods:data analysis light pollution

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