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Friction 2024年第8期12卷 1680-1695页

作者： Wenjing zhang Xin zhang Tiancheng ai Dan GUO Guoshun pAN State Key Laboratory of Tribology in Advanced Equipment Tsinghua UniversityBeijing 100084China Guangdong provincial Key Laboratory of Optomechatronics Shenzhen 518057China

As a crucial part in micro-electromechanical manufacture,local ultra-precision processing of highly ductile copper is expected to be realized by fluid jet polishing(FJp),which widely utilized in optical *** copper exhibits different wear behavior from stiff and brittle material,there is currently no abrasive wear prediction model applicable for copper to investigate the polishing *** research reveals that the copper material removal is dominated by deformation wear rather than cutting wear through abrasive jet impact experiments and localized wear scars analysis.A three-dimensional gas-liquid-particle triphasic wear model for copper in FJp is developed by considering impact energy and wear mechanism ***,validation assessments at various working pressures and imp.ngement angles achieve the goodness-of-fit up to 0.92–0.97 in quantitative comparison between simulations and experimental measurements,which demonstrate the wear prediction ability of the proposed *** investigation facilitates a better understanding of copper wear mechanism and provides theoretical guidance for FJp process optimization.

关键词： fluid jet polishing(FJp) wear mechanism computational fluid mechanics wear model material removal

Reliability ensemble averaging reduces surface wind speed projection uncertainties in the 21st century over China

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Advances in Climate Change Research 2024年第2期15卷 222-229页

作者： Zheng-Tai zhang Chang-ai XU Key Laboratory for Semi-Arid Climate Change of the Ministry of Education College of Atmospheric SciencesLanzhou UniversityLanzhou 730000China

Accurate prediction of future surface wind speed(SWS)changes is the basis of scientific planning for wind *** studies have projected SWS changes in the 21st century over China on the basis of the multi-model ensemble(MME)of the 6th Coupled Model Intercomparison project(CMIp6).However,the simulation capability for SWS varies greatly in CMIp6 multi-models,so the MME results still have large *** this study,we used the reliability ensemble averaging(REA)method to assign each model different weights according to their performances in simulating historical SWS changes and project the SWS under different shared socioeconomic pathways(SSps)in *** results indicate that REA considerably improves the SWS simulation capacity of CMIp6,eliminating the overestimation of SWS by the MME and increasing the simulation capacity of spatial *** spatial correlations with observations increased from 0.56 for the MME to 0.85 for ***,REA could eliminate the overestimation of the SWS by 33%in *** for southeastern China,the SWS generally decreases over China in the near term(2020-2049)and later term(2070-2099),particularly under high-emission *** SWS reduction projected by REA is twice as high as that by the MME in the near term,reaching-4%to-3%.REA predicts a larger area of increased SWS in the later term,which expands from southeastern China to eastern *** study helps to reduce the projected SWS uncertainties.

关键词： Surface wind speed Uncertainty Multi-model ensemble Reliability ensemble averaging CMIp6

Three-dimensional numerical analysis of plant-soil hydraulic interactions on pore water pressure of vegetated slope under different rainfall patterns

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第9期16卷 3696-3706页

作者： Haowen Guo Charles Wang Wai ng Qi zhang Department of Civil and Environmental Engineering The Hong Kong University of Science and TechnologyHong KongChina

Understanding the pore water pressure distribution in unsaturated soil is crucial in predicting shallow landslides triggered by rainfall,mainly when dealing with different temporal patterns of rainfall ***,the hydrological response of vegetated slopes,especially three-dimensional(3D)slopes covered with shrubs,under different rainfall patterns remains unclear and requires further *** address this issue,this study adopts a novel 3D numerical model for simulating hydraulic interactions between the root system of the shrub and the surrounding *** series of numerical parametric studies are conducted to investigate the influences of slope inclination,rainfall pattern and rainfall *** rainfall patterns(advanced,bimodal,delayed,and uniform)and two rainfall durations(4-h intense and 168-h mild rainfall)are considered to study the hydrological response of the *** computed results show that 17%higher transpiration-induced suction is found for a steeper slope,which remains even after a short,intense rainfall with a 100-year return *** extreme rainfalls with advanced(pA),bimodal(pB)and uniform(pU)rainfall patterns need to be considered for the short rainfall duration(4 h),while the delayed(pD)and uniform(pU)rainfall patterns are highly recommended for long rainfall durations(168 h).The presence of plants can improve slope stability markedly under extreme rainfall with a short duration(4 h).For the long duration(168 h),the benefit of the plant in preserving pore-water pressure(pWp)and slope stability may not be sufficient.

关键词： Root-soil interactions Rainfall patterns Slope stability Three-dimensional(3D)

A model reduction approach for discrete-time linear time-variant systems with delayed inputs

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Science China(Information Sciences) 2024年第4期67卷 197-217页

作者： ai-Guo WU Guang-Ren DUAN Yu WAng Jie zhang School of Mechanical Engineering and Automation Harbin Institute of Technology(Shenzhen) HIT Wuhu Robot Technology Research Institute Center for Control Science and Technology Southern University of Science and Technology

A model reduction approach is presented for discrete-time linear time-variant input-delayed systems. According to this proposed approach, a dynamical variable is constructed by taking advantage of the current state and historical information of input. It is revealed that the behavior of this dynamical variable is governed by a discrete-time linear delay-free system. It is worth noting that the presented variable transformation does not require the system matrix to be invertible. Based on the reduced delay-free models,stabilizing control laws can be easily obtained for the original delayed system. For the case with a single input delay, the constructed variable is an exact prediction for the future state, and thus the stabilizing control law could be designed by replacing the future state with its prediction. Finally, three discrete-time periodic systems with delayed input are employed to illustrate how to utilize the presented model reduction approaches.

关键词： reduction approach predictor-based feedback time-varying systems delayed input periodic system

Numerical analysis of wind effects on aerodynamic characteristics of a ducted fan

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Chinese Journal of Aeronautics 2024年第5期37卷 263-280页

作者： Yiwei LUO Tianfu ai Yuhang HE Bin XU Yup.ng QIAN Yangjun zhang State Key Laboratory of Intelligent Green Vehicle and Mobility School of Vehicle and MobilityTsinghua UniversityBeijing 100084China Key Laboratory of Conveyance and Equipment Ministry of Education East China Jiaotong UniversityNanchang 330013China Vehicle Research Center School of Mechanical EngineeringBeijing Institute of TechnologyBeijing 100081China Beijing Institute of Technology Chongqing Innovation Center Chongqing 401120China

Ducted fans have been extensively used in Unmanned Aerial Vehicles(UAVs)for a variety of missions because of high efficiency,high safety and low ***,as a kind of typical meteorological condition,brings significant aerodynamic interference to the ducted fan,which seriously threatens flight stability and *** this work,the numerical simulation with the Unsteady Reynolds Averaged Navier-Stokes(URANS)method and the sliding mesh technique is performed to evaluate the steady wind *** results show that the wind will lead to serious unsteady effects in the flow field,and the thrust fluctuates at the blade passing frequency of 200 *** the wind speed increases,the rotor thrust increases,the duct thrust decreases,and the total thrust changes *** instability may occur when the wind speed exceeds 8 m/*** the angle of low-speed wind increases,the rotor thrust changes little,the duct thrust increases,and the total thrust *** addition,we figure out that cases with the same crosswind ratio are similar in results,and increasing the rotating speed or fan radius is beneficial to performance improvement in *** findings are essential to the ducted fan design and UAV flight control design for stable and safe operations in wind conditions.

关键词： Unmanned Aerial Vehicle(UAV) Ducted fan Wind effect Thrust fluctuations Computational Fluid Dynamics(CFD)

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Self-derivation and reconstruction of silver nanoparticle reinforced cobalt-nickel bimetallic hydroxides through interface engineering for overall water splitting

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Journal of Energy Chemistry 2024年第3期90卷 590-599,I0013页

作者： Yan Li Jie Han Weiwei Bao Junjun zhang Taotao ai Mameng Yang Chunming Yang p.ngfei zhang National and Local Joint Engineering Laboratory for Slag Comprehensive Utilization and Environmental Technology School of Materials Science and EngineeringShaanxi University of TechnologyHanzhong 723000ShaanxiChina State Key Laboratory of High-efficiency Utilization of Coal and Green Chemical Engineering College of Chemistry&Chemical EngineeringNingxia UniversityYinchuan 750021NingxiaChina College of Chemistry&Chemical Engineering Yan’an UniversityYan’an 716000ShaanxiChina School of Chemistry and Chemical Engineering Shanghai Jiao Tong UniversityShanghai 200240China

Designing efficient and long-lasting non-metal electrocatalysts is an urgent task for addressing the issue of kinetic hysteresis in electrochemical oxidation *** bimetallic hydroxides,catalyzing the oxygen evolution reaction(OER),have significant research potential because hydroxide reconstruction to generate an active phase is a remarkable ***,the complete reconstruction of ultrathin CoNi(OH)_(2) nanosheets was achieved by embedding Ag nanoparticles into the hydroxide to induce a spontaneous redox reaction(SRR),forming heterojunction Ag@CoNi(OH)_(2) for bifunctional *** calculations and in situ Raman and ex situ characterizations revealed that the inductive effect of the Ag cation redistributed the charge to promote phase transformation to highly activate Ag-modified *** Co-Ni dual sites in Co/NiOOH serve as novel active sites for optimizing the intermediates,thereby weakening the barrier formed by OOH^*.Ag@CoNi(OH)_(2) required a potential of 1.55 V to drive water splitting at a current density of 10 mA cm^(-2),with nearly 98.6% Faraday *** ion induction and triggering of electron regulation in the OER via the synergistic action of the heterogeneous interface and surface reconstruction,this strategic design can overcome the limited capacity of bimetallic hydroxides and bridge the gap between the basic theory and industrialization of water decomposition.

关键词： Surface reconstruction Bimetallic hydroxides Ag nanoparticle Operando Raman Overall water splitting

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Feasible strategy for the nitrogen fixation and humification quality improvement by spent mushroom substrate as conditioning agent

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International Journal of Agricultural and Biological Engineering 2024年第3期17卷 235-240页

作者： Shuang ai Yuanbei zhang Guoxiang Zheng College of Engineering Northeast Agricultural UniversityHarbin 150030China Key Laboratory of Swine Facilities Engineering Ministry of Agriculture and Rural AffairsHarbin 50030China Heilongjiang Key Laboratory of Technology and Equipment for the Utilization of Agricultural Renewable Resources Harbin 150030China

There is an overlooked problem which increasing microbial abundance while reducing nitrogen loss during *** study investigated the viability of spent mushroom substrate(SMS)as conditioners in the aerobic composting of kitchen waste(KW)with cattle manure(CM).The variation of temperature,pH,C/N,organic matter,cellulose,hemicelluloses,germination index(GI),and microflora structure were explored to evaluate the potential in accelerating maturity and nitrogen fixation by SMS *** results showed that the addition of SMS accelerated the heating rate,prolonged the high temperature time,and decreased organic matter,hemicellulose,and cellulose by 17.49%,23.61%,and 18.62%,*** GI reached 105.86%with SMS addition,while 74.17%was found in control treatment after *** changed the microbial community composition and increased the species ***,Clostridium XI and Azomonas were dominant bacteria,which increased the retention of nitrogen,promoted organic matter degradation and reduce compost *** study can provide a feasible strategy for nitrogen fixation in the field of organic waste recycling.

关键词： spent mushroom substrate conditioning agent nitrogen fixation humification quality aerobic composting

Constitutive Behavior of the Interface between UHpC and Steel plate without Shear Connector:From Experimental to Numerical Study

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Computer Modeling in Engineering & Sciences 2024年第8期140卷 1863-1888页

作者： Zihan Wang Boshan zhang Hui Wang Qing ai Xingchun Huang School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China Department of Bridge Engineering Tongji UniversityShanghai200092China

The application of ultra-high performance concrete(UHpC)as a covering layer for steel bridge decks has gained widespread *** employing a connection without a shear connector between the steel plate and UHpC,namely,the sandblasted interface and the epoxy adhesive with sprinkled basalt aggregate interface,the installation cannot only be simplified but also the stress concentration resulting from the welded shear connectors can be *** study develops constitutive models for these two interfaces without shear connectors,based on the interfacial pull-off and push-out *** validation,three-point bending tests on the steel-UHpC composite plates are *** results indicated that the proposed bilinear traction-separation model for the sandblasted interface and the trapezoidal traction-separation model for the epoxy adhesive with sprinkled basalt aggregate interface can generally calibrate the interfacial ***,the utilization of the experimentally determined pure shear strength underestimates the load-carrying capacity of the composite plates in the case of three-point bending *** recalling the Mohr-Coulomb criterion,this underestimation is attributed to the enhancement of the interface shear strength by the presence of normal stress.

关键词： Cohesive zone model interfacial behavior finite element simulation UHpC steel plate

Chiral mesostructured hematite with temperature-independent magnetism due to spin confinement

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Nano Research 2024年第3期17卷 2019-2024页

作者： Baiwen zhang Jing ai Yingying Duan Te Bai Lu Han Shunai Che School of physics Science and Engineering Tongji UniversityShanghai 200092China School of Chemistry and Chemical Engineering Tongji UniversityShanghai 200092China Wuxi Vocational College of Science and Technology Wuxi 214028China School of Chemistry and Chemical Engineering Frontiers Science Center for Transformative MoleculesState Key Laboratory of Metal Matrix CompositesShanghai Jiao Tong UniversityShanghai 200240China

Hematite(α-Fe_(2)O_(3))is known to undergo conversion from weak ferromagnetic to antiferromagnetic as the temperature decreases below the Morin temperature(TM=250 K)due to spin moment rotation occurring during the Morin transition(MT).Herein,we endowed hematite with mesostructured chirality to maintain weak ferromagnetism without *** mesostructured hematite(CMH)nanoparticles were prepared by a hydrothermal method with glutamic acid(Glu)as the symmetry-breaking *** triangular bipyramidal CMH nanoparticles were composed of helically cleaved nanoflakes with twisted crystal ***-cooled(FC)magnetization measurements showed that the magnetic moments of CMH were stabilized without MT within the temperature range of 10–300 *** loop measurements confirmed the weak ferromagnetism of *** enhanced Dzyaloshinskii–Moriya interaction(DMI)was speculated to be responsible for the temperature-independent weak ferromagnetism,in which the spin configuration would be confined with canted antiferromagnetic coupling due to the mesostructured chirality of CMH.

关键词： hematite chiral mesostructure Dzyaloshinskii–Moriya interaction weak ferromagnetism antiferromagnetic material temperature-independent magnetism

Quantification of Central and Eastern China's atmospheric CH_(4) enhancement changes and its contributions based on machine learning approach

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Journal of Environmental Sciences 2024年第4期138卷 236-248页

作者： Xinyue ai Cheng Hu Yanrong Yang Leying zhang Huili Liu Junqing zhang Xin Chen Guoqiang Bai Wei Xiao College of Biology and the Environment Joint Center for sustainable Forestry in Southern ChinaNanjing Forestry UniversityNanjing 210037China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD) Nanjing University of Information Science&TechnologyNanjing 210044China Guang’an Vocational&Technical College Guangan 638550China HuaNan Meteorological Administration Huanan 154400China

Methane is the second largest anthropogenic greenhouse gas,and changes in atmospheric methane concentrations can reflect the dynamic balance between its emissions and ***,the monitoring of CH_(4) concentration changes and the assessment of underlying driving factors can provide scientific basis for the government’s policy making and *** is the world’s largest emitter of anthropogenic ***,due to the lack of ground-based observation sites,little work has been done on the spatial-temporal variations for the past decades and influencing factors in China,especially for areas with high anthropogenic emissions as Central and Eastern *** to quantify atmospheric CH_(4) enhancements trends and its driving factors in Central and Eastern China,we combined the most up-to-date TROpOMI satellite-based column CH_(4)(xCH_(4))concentration from 2018 to 2022,anthropogenic and natural emissions,and a random forest-based machine learning approach,to simulate atmospheric xCH_(4) enhancements from 2001 to *** results showed that(1)the random forest model was able to accurately establish the relationship between emission sources and xCH_(4) enhancement with a correlation coefficient(R^(2))of 0.89 and a root mean-square error(RMSE)of 11.98 ppb;(2)The xCH_(4) enhancement only increased from 48.21±2.02 ppb to 49.79±1.87 ppb from the year of 2001 to 2018,with a relative change of 3.27%±0.13%;(3)The simulation results showed that the energy activities and waste treatment were the main contributors to the increase in xCH_(4) enhancement,contributing 68.00% and 31.21%,respectively,and the decrease of animal ruminants contributed-6.70% of its enhancement trend.

关键词： TROpOMI Methane column concentrations Anthropogenic sources Random Forest model

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