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

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

作者： Yiwei LUO Tianfu AI Yuhang HE Bin XU Yuping 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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High-performance terahertz modulators induced by substrate field in Te-based all-2D heterojunctions

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Light(Science & Applications) 2024年第3期13卷 577-586页

作者： Pujing zhang Qihang Liang Qingli Zhou Jinyu Chen Menglei Li Yuwang Deng Wanlin Liang Liangliang zhang Qinghua zhang Lin Gu Chen Ge kui-juan Jin Cunlin zhang Guozhen Yang Department of Physics Key Laboratory of Terahertz OptoelectronicsMinistry of Educationand Beijing Advanced Innovation Center for Imaging Theory and TechnologyCapital Normal UniversityBeijing 100048China Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of SciencesBeijing 100190China Department of Materials Science and Engineering Beijing National Center for Electron Microscopy and Laboratory of Advanced MaterialsTsinghua UniversityBeijing 100084China

High-performance active terahertz modulators as the indispensable core components are of great importance for the next generation communication ***,they currently suffer from the tradeoff between modulation depth and ***,we introduce two-dimensional(2D)tellurium(Te)nanofilms with the unique structure as a new class of optically controlled terahertz modulators and demonstrate their integrated heterojunctions can successfully improve the device performances to the optimal and applicable levels among the existing all-2D broadband *** photoresponse measurements confirm the significant impact of the stacking *** first clarify the direction of the substrate-induced electric field through first-principles calculations and uncover the unusual interaction mechanism in the photoexcited carrier dynamics associated with the charge transfer and interlayer exciton *** advances the fundamental and applicative research of Te nanomaterials in high-performance terahertz optoelectronics.

关键词： performance field terahertz

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Experimental and numerical investigation of the impacts of rotor tip-rake on excitation forces of pump-jet propulsors

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Journal of Hydrodynamics 2024年第1期36卷 142-157页

作者： Xue-qin Ji Xiao-song zhang Chen-jun Yang Xiao-qian Dong State Key Laboratory of Ocean Engineering Marine Numerical Experiment CentreSchool of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai200240China CSSC Shanghai Marine Energy Saving Technology Co. Ltd.Shanghai200011China China Ship Scientific Research Center Shanghai Branch Shanghai200011China

The tip-clearance flow in a pump-jet propulsor exerts great impacts on the fluctuating pressures and resultant unsteady forces,which are important sources of structural vibrations and radiated noise *** blade geometry close to the tip is an important factor determining the vortex strength in the tip-clearance *** the open-water condition,the effects of raking the rotor tips on the duct-surface fluctuating pressures and the resultant unsteady forces acting on different components of the propulsor are investigated via physical model experiments and the numerical solution of Reynolds-averaged Navier-Stokes(RANS)equations coupled with the SST k-ωturbulence *** measured and simulated results of hydrodynamic pressures are consistent to each other,and the simulated flows help better understand why the fluctuating pressures change with the tip *** strong fluctuations of duct-surface pressures are caused by intensive tip separation *** duct-surface pressure fluctuations are effectively reduced by using the rake distribution near the tip towards blade back side and,for the combination of the five-bladed rotor and the seven-bladed stator,the resultant unsteady horizontal(and vertical)forces acting on the duct and stator are also reduced;while increasing rake leads to negative effect on pressure fluctuations and unsteady horizontal(and vertical)forces acting on all the components of the propulsor.

关键词： Pump-jet tip-clearance tip-rake fluctuating pressures excitation forces

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Prediction of the thermal conductivity of Mg–Al–La alloys by CALPHAD method

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 129-137页

作者： Hongxia Li Wenjun Xu Yufei zhang Shenglan Yang Lijun zhang Bin Liu Qun Luo qian Li State Key Laboratory of Advanced Special Steels&Shanghai Key Laboratory of Advanced Ferrometallurgy&School of Materials Science and Engineering Shanghai UniversityShanghai 200444China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China National Key Laboratory of Advanced Casting Technologies Chongqing UniversityChongqing 400044China

Mg-Al alloys have excellent strength and ductility but relatively low thermal conductivity due to Al *** accurate prediction of thermal conductivity is a prerequisite for designing Mg-Al alloys with high thermal ***,databases for predicting temperature-and composition-dependent thermal conductivities must be *** this study,Mg-Al-La alloys with different contents of Al2La,Al3La,and Al11La3phases and solid solubility of Al in the α-Mg phase were *** influence of the second phase(s) and Al solid solubility on thermal conductivity was *** results revealed a second phase transformation from Al_(2)La to Al_(3)La and further to Al_(11)La_(3)with the increasing Al content at a constant La *** degree of the negative effect of the second phase(s) on thermal diffusivity followed the sequence of Al2La>Al3La>Al_(11)La_(3).Compared with the second phase,an increase in the solid solubility of Al in α-Mg remarkably reduced the thermal *** the basis of the experimental data,a database of the reciprocal thermal diffusivity of the Mg-Al-La system was established by calculation of the phase diagram (CALPHAD)*** a standard error of±1.2 W/(m·K),the predicted results were in good agreement with the experimental *** established database can be used to design Mg-Al alloys with high thermal conductivity and provide valuable guidance for expanding their application prospects.

关键词： magnesium alloy thermal conductivity thermodynamic calculations materials computation

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New Insights into Microplastic Contamination in Different Types of Leachates: Abundances, Characteristics, and Potential Sources

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Engineering 2024年第6期37卷 62-68页

作者： Lei zhang Wentao Zhao Liang zhang Zhenxiao Cai Ruiqi Yan Xia Yu Damià Barceló qian Sui State Environmental Protection Key Laboratory of Environmental Risk Assessment and Control on Chemical Process School of Resources and Environmental EngineeringEast China University of Science and TechnologyShanghai 200237China State Key Laboratory of Pollution Control and Resource Reuse College of Environmental Science and EngineeringTongji UniversityShanghai 200092China Shanghai Institute of Pollution Control and Ecological Security Shanghai 200092China PerkinElmer Inc.Shanghai 201203China Maihai Environmental Protection Technology Co. Ltd.SuzhouJiangsu 215000China Department of Environmental Chemistry Institute of Environmental Assessment and Water ResearchSpanish Council for Scientific Research(IDAEA-CSIC)Barcelona 08034Spain

Municipal solid waste(MSW)is an important destination for abandoned *** the waste disposal process,large plastic debris is broken down into microplastics(MPs)and released into the ***,current research only focuses on landfill leachates,and the occurrence of MPs in other leachates has not been ***,herein,the abundance and characteristics of MPs in three types of leachates,namely,landfill leachate,residual waste leachate,and household food waste leachate,were studied,all leachates were collected from the largest waste disposal center in *** results showed that the average MP abundances in the different types of leachates ranged from(129±54)to(1288±184)MP particles per liter(particlesL1)and the household food waste leachate exhibited the highest MP abundance(p80%)of small MPs(20–100 lm)in landfill leachates compared to other *** the best of our knowledge,this is the first study discussing the sources of MPs in different leachates,which is important for MP pollution control during MSW disposal.

关键词： Microplastics Landfill leachate Residual waste leachate Household food waste leachate Source

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Comprehensive analysis of gene mutations and mismatch repair in Chinese colorectal cancer patients

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World Journal of Gastrointestinal Oncology 2024年第6期16卷 2673-2682页

作者： Huang Chen Rui-Ying Jiang Zhan Hua Xiao-Wei Wang Xiao-Li Shi Ye Wang qian-qian Feng Jie Luo Wu Ning Yan-Fen Shi Da-kui zhang Bei Wang Jian-Zheng Jie Ding-Rong Zhong Department of Pathology China-Japan Friendship HospitalBeijing 100029China Department of Gastrointestinal Surgery China-Japan Friendship HospitalBeijing 100029China Department of Scientific Research GeneisBeijing 100012China

BACKGROUND RAS,BRAF,and mismatch repair(MMR)/microsatellite instability(MSI)are crucial biomarkers recommended by clinical practice guidelines for colorectal cancer(CRC).However,their characteristics and influencing factors in Chinese patients have not been thoroughly *** To analyze the clinicopathological features of KRAS,NRAS,BRAF,and PIK3CA mutations and the DNA MMR status in *** We enrolled 2271 Chinese CRC patients at the China-Japan Friendship *** proteins were tested using immunohistochemical analysis,and the KRAS/NRAS/BRAF/PIK3CA mutations were determined using quantitative polymerase chain *** status was determined using an MSI detection *** analyses were conducted using SPSS software and logistic *** The KRAS,NRAS,BRAF,and PIK3CA mutations were detected in 44.6%,3.4%,3.7%,and 3.9% of CRC patients,*** mutations were more likely to occur in patients with moderate-to-high *** mutations were more likely to occur in patients with right-sided CRC,poorly differentiated,or no perineural *** MMR(dMMR)was detected in 7.9% of all patients and 16.8% of those with mucinous ***,NRAS,BRAF,and PIK3CA mutations were detected in 29.6%,1.1%,8.1%,and 22.3% of patients with dMMR,*** dMMR was more likely to occur in patients with a family history of CRC,aged<50 years,right-sided CRC,poorly differentiated histology,no perineural invasion,and with carcinoma in situ,stage I,or stage II *** This study analyzed the molecular profiles of KRAS,NRAS,BRAF,PIK3CA,and MMR/MSI in CRC,identifying key influencing factors,with implications for clinical management of CRC.

关键词： Colorectal cancer Deficient mismatch repair Microsatellite instability Gene mutation Comprehensive analysis

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The study of intelligent algorithm in particle identification of heavy-ion collisions at low and intermediate energies

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Nuclear Science and Techniques 2024年第2期35卷 170-182页

作者： Gao-Yi Cheng qian-Min Su Xi-Guang Cao Guo-qiang zhang School of Electronic and Electrical Engineering Shanghai University of Engineering ScienceShanghai 201620China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201210China Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China

Traditional particle identification methods face timeconsuming,experience-dependent,and poor repeatability challenges in heavy-ion collisions at low and intermediate *** urgently need solutions to the dilemma of traditional particle identification *** study explores the possibility of applying intelligent learning algorithms to the particle identification of heavy-ion collisions at low and intermediate *** intelligent algorithms,including XgBoost and TabNet,were selected to test datasets from the neutron ion multi-detector for reaction-oriented dynamics(NIMROD-ISiS)and Geant4 ***-based machine learning algorithms and deep learning algorithms *** show excellent performance and generalization *** additional data features besides energy deposition can improve the algorithm’s performance when the data distribution is *** learning algorithms can be applied to solve the particle identification problem in heavy-ion collisions at low and intermediate energies.

关键词： Heavy-ion collisions at low and intermediate energies Machine learning Ensemble learning algorithm Particle identification Data imbalance

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Description of martensitic transformation kinetics in Fe-C-X(X = Ni,Cr,Mn,Si) system by a modified model

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International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 1026-1036页

作者： Xiyuan Geng Hongcan Chen Jingjing Wang Yu zhang Qun Luo qian Li State Key Laboratory of Advanced Special Steels&Shanghai Key Laboratory of Advanced Ferrometallurgy&School of Materials Science and Engineering Shanghai UniversityShanghai 200444China Ansteel Beijing Research Institute Co. LtdBeijing 102211China National Engineering Research Center for Magnesium Alloys Chongqing UniversityChongqing 400044China College of Materials Science and Engineering Chongqing UniversityChongqing 400044China National Key Laboratory of Advanced Casting Technologies Chongqing UniversityChongqing 400044China

Controlling the content of athermal martensite and retained austenite is important to improving the mechanical properties of high-strength steels,but a mechanism for the accurate description of martensitic transformation during the cooling process must be *** present,frequently used semi-empirical kinetics models suffer from huge errors at the beginning of transformation,and most of them fail to exhibit the sigmoidal shape characteristic of transformation *** describe the martensitic transformation process accurately,based on the Magee model,we introduced the changes in the nucleation activation energy of martensite with temperature,which led to the varying nucleation rates of this model during martensitic *** to the calculation results,the relative error of the modified model for the martensitic transformation kinetics curves of Fe-C-X(X = Ni,Cr,Mn,Si) alloys reached 9.5% compared with those measured via the thermal expansion *** relative error was approximately reduced by two-thirds compared with that of the Magee *** incorporation of nucleation activation energy into the kinetics model contributes to the improvement of its precision.

关键词： Fe-C-X system martensitic transformation kinetics curve semi-empirical model nucleation activation energy

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A macro-mesoscopic constitutive model for porous and cracked rock under true triaxial conditions

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第8期16卷 3080-3098页

作者： Li qian Zuguo Mo Jianhai zhang Xianglin Xing Ru zhang Tianzhi Yao Yunpeng Gao State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resources and HydropowerSichuan UniversityChengdu610065China Power China Chengdu Engineering Corporation Limited Chengdu610072China

The complex mechanical and damage mechanisms of rocks are intricately tied to their diverse mineral compositions and the formation of pores and cracks under external *** rock tests reveal a complex interplay between the closure of porous defects and the propagation of induced cracks,presenting challenges in accurately representing their mechanical properties,especially under true triaxial stress *** paper proposes a conceptualization of rock at the mesoscopic level as a two-phase composite,consisting of a bonded medium matrix and frictional medium *** bonded medium is characterized as a mesoscopic elastic material,encompassing various minerals surrounding porous *** mechanical properties are determined using the mixed multi-inclusion *** of the bonded medium into the frictional medium occurs through crack extension,with its elastoplastic properties defined by the DruckerePrager yield criterion,accounting for hardening,softening,and *** and Eshelby’s equivalent inclusion methods are applied to the bonded and frictional media,*** macroscopic mechanical properties of the rock are derived from these mesoscopic ***,a True Triaxial Macro-Mesoscopic(TTMM)constitutive model is *** model effectively captures the competitive effect and accurately describes the stress-deformation characteristics of *** the TTMM model,the strains resulting from porous defect closure and induced crack extension are differentiated,enabling quantitative determination of the associated damage evolution.

关键词： Micromechanics Macroemesoscopic Homogenization Constitutive model Competitive effect

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Sex-biased single-cell genetic landscape in mice with autism spectrum disorder

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Journal of Genetics and Genomics 2024年第3期51卷 338-351页

作者： qian zhang Yongjie Wang Jie Tao Ruixue Xia Yijie zhang Zhirui Liu Jiwei Cheng Department of Neurology and Central Laboratory Putuo HospitalShanghai University of Traditional Chinese MedicineShanghai 200062China School of Pharmacy Hangzhou Normal UniversityHangzhouZhejiang 311121China Department of Respiratory and Critical Care Medicine Henan University Huaihe HospitalKaifengHenan 475099China

Autistic spectrum disorder(ASD)is a male-biased,heterogeneous neurodevelopmental disorder that affects approximately 1%e2%of the *** exposure to valproic acid(VPA)is a recognized risk factor for ASD,but the cellular and molecular basis of VPA-induced ASD at the single-cell resolution is ***,we aim to compare the cellular and molecular differences in the hippocampus between male and female prenatal mice with ASD at the single-cell transcriptomic *** transcriptomes of more than 45,000 cells are assigned to 12 major cell types,including neurons,glial cells,vascular cells,and immune *** type-specific genes with altered expression after prenatal VPA exposure are analyzed,and the largest number of differentially expressed genes(DEGs)are found in neurons,choroid plexus epithelial cells,and *** microglia,several pathways related to inflammation are found in both males and females,including the tumor necrosis factor(TNF),nuclear factor kappa B(NF-kB),toll-like receptor(TLR),and mitogen-activated protein kinase(MAPK)signaling pathways,which are important for the induction of autistic-like ***,we note that several X-linked genes,including Bex1,Bex3,and Gria3,were among the male-specific DEGs of *** pioneering study describes the landscape of the transcriptome in the hippocampus of autistic *** elucidation of sexual differences could provide innovative strategies for the prevention and treatment of ASD.

关键词： Autistic spectrum disorder(ASD) Sex Single cell Neurons Microglia

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