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Modeling and analysis for material removal and surface roughness in fluid jet polishing of optical glass

Friction 2024年第7期12卷 1548-1563页

作者： Zhongchen cao Ming WANG Haitao LIU Tian HUANG Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education Tianjin UniversityTianjin 300072China School of Engineering The University of WarwickCoventry CV47ALUK

luid jet polishing(FJP)is a non-contact polishing technology that can fabricate free-form optical surfaces with sub-micron-level form accuracy and nano-level surface roughness,especially for hard and brittle *** surface generation model of FJP can be used to guide the determination and optimization of process parameters and is of great significance for understanding the evolution mechanism of surface ***,predictive models for the microscopic topography of polished surfaces are still *** study established a macroscopic surface profile model for predicting 3D material removal characteristics and surface texture by combining the 3D computer fluid dynamics(CFD)simulation model and single-particle erosion mechanism.A fractal theory-based erosion model has been built to calculate the material removal caused by the erosion of a single abrasive particle on the rough surface;thus,it predicts the micro-topography and surface roughness of the polished samples.A series of polishing experiments were conducted to analyze the feasibility and accuracy of the model quantitatively and study the influence mechanism of process parameters on the material removal characteristics and surface *** indicated that the models could well predict material removal and surface *** prediction accuracy of the surface roughness Ra and maximum removal depth is better than 91.6%and 90%,*** is also found that the material removal rate of FJP could reach 0.517 mm3/min,and the surface roughness convergence rate could reach 62.9%.

关键词： fluid jet polishing(FJP) computational fluid dynamics(CFD) material removal mechanism surface roughness theoretical model

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不饱和聚酯包覆层流动及浇注的仿真模拟

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含能材料 2022年第11期30卷 1106-1117页

作者：张豫鲁刘奔奔陈国辉曹贝贝何吉宇李向梅杨荣杰北京理工大学材料学院北京100081 北京航空航天大学前沿科学技术创新研究院北京100191 西安近代化学研究所陕西西安710065 北京理工大学化学与化工学院北京100081

固体火箭发动机技术的发展对现有的包覆层生产技术提出了新的挑战,采用热固性树脂作为基体,结合连续自动化包覆技术,可快速得到成型完整、性能优异的包覆层,是近年来较为热门的包覆层生产方法。本研究分析了不饱和聚酯(UPR)包覆层的流... 详细信息

固体火箭发动机技术的发展对现有的包覆层生产技术提出了新的挑战,采用热固性树脂作为基体,结合连续自动化包覆技术,可快速得到成型完整、性能优异的包覆层,是近年来较为热门的包覆层生产方法。本研究分析了不饱和聚酯(UPR)包覆层的流动性和浇注条件,通过在Fontana‑Kiuna模型基础上引入指数函数,得到匹配的化学流变模型,建立了UPR固化时粘度与时间、温度的函数关系,得到了适合包覆层浇注操作的温度;以Bird‑Carreau幂律方程建立UPR流体的本构方程,使用Polyflow软件在前述温度下对恒速模式和恒压模式下UPR包覆层的浇注过程进行模拟,分析了浇注速率、浇注压力对充填完整性的影响,预测了包覆层的填充体积分数分布、流动速率分布和熔接线位置。结果表明,为了保证UPR包覆层浇注完整,浇注温度应该在35℃以下,浇注压力应大于1 MPa,入口流速应大于150 mm^(3)·s^(-1)且小于175 mm^(3)·s^(-1)。

关键词：不饱和聚酯(UPR) 包覆层流变仿真模拟

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Ionic Liquid-Enhanced Assembly of Nanomaterials for Highly Stable Flexible Transparent Electrodes

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Nano-Micro Letters 2024年第7期16卷 441-455页

作者： Jianmin Yang Li Chang Xiqi Zhang Ziquan cao Lei Jiang Key Laboratory of Bio-Inspired Materials and Interfacial Science Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190People’s Republic of China University of Chinese Academy of Sciences Beijing 100049People’s Republic of China College of Chemistry and Chemical Engineering Chongqing University of TechnologyChongqing 400054People’s Republic of China Binzhou Institute of Technology Binzhou 256600People’s Republic of China Nanomics Biotechnology Co. Ltd.HangzhouPeople’s Republic of China

The controlled assembly of nanomaterials has demon-strated significant potential in advancing technological ***,achieving highly efficient and low-loss assembly technique for nanomate-rials,enabling the creation of hierarchical structures with distinctive func-tionalities,remains a formidable ***,we present a method for nanomaterial assembly enhanced by ionic liquids,which enables the fabrication of highly stable,flexible,and transparent electrodes featuring an organized layered *** utilization of hydrophobic and non-volatile ionic liquids facilitates the production of stable interfaces with water,effectively preventing the sedimentation of 1D/2D nanomaterials assembled at the ***,the interfacially assembled nanomaterial monolayer exhibits an alternate self-climbing behavior,enabling layer-by-layer transfer and the formation of a well-ordered MXene-wrapped silver nanowire network *** resulting composite film not only demonstrates exceptional photoelectric performance with a sheet resistance of 9.4Ωsq^(-1) and 93%transmittance,but also showcases remarkable environmental stability and mechanical *** noteworthy is its application in transparent electromagnetic interference shielding materials and triboelectric nanogenerator *** research introduces an innovative approach to manufacture and tailor functional devices based on ordered nanomaterials.

关键词： Ionic liquids Assembly Silver nanowires MXene nanosheets Flexible transparent electrodes

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Joint position optimization,user association,and resource allocation for load balancing in UAV-assisted wireless networks

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Digital Communications and Networks 2024年第1期10卷 25-37页

作者： Daosen Zhai Huan Li Xiao Tang Ruonan Zhang Haotong cao School of Electronics and Information Northwestern Polytechnical UniversityXian710072China State Key Laboratory of Integrated Services Networks Xidian UniversityXian710071China Department of Computing Hong Kong Polytechnic UniversityHong Kong SARChina

Unbalanced traffic distribution in cellular networks results in congestion and degrades spectrum *** tackle this problem,we propose an Unmanned Aerial Vehicle(UAV)-assisted wireless network in which the UAV acts as an aerial relay to divert some traffic from the overloaded cell to its adjacent underloaded *** fully exploit its potential,we jointly optimize the UAV position,user association,spectrum allocation,and power allocation to maximize the sum-log-rate of all users in two adjacent *** tackle the complicated joint optimization problem,we first design a genetic-based algorithm to optimize the UAV ***,we simplify the problem by theoretical analysis and devise a low-complexity algorithm according to the branch-and-bound method,so as to obtain the optimal user association and spectrum allocation *** further propose an iterative power allocation algorithm based on the sequential convex approximation *** simulation results indicate that the proposed UAV-assisted wireless network is superior to the terrestrial network in both utility and throughput,and the proposed algorithms can substantially improve the network performance in comparison with the other schemes.

关键词： Load balance Unmanned aerial vehicle Userassociation Resource management

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Advances of graphdiyne-supported metal catalysts in thermocatalytic reactions

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Nano Research 2024年第4期17卷 2223-2233页

作者： Jia Yu Yida Yang Yuliang Li Changyan cao Weiguo Song beijing National Laboratory for Molecular Sciences CAS Research/Education Center for Excellence in Molecular SciencesLaboratory of Molecular Nanostructures and NanotechnologyInstitute of ChemistryChinese Academy of SciencesBeijing 100190China School of Chemical Sciences University of Chinese Academy of SciencesBeijing 100049China beijing National Laboratory for Molecular Sciences CAS Research/Education Center for Excellence in Molecular SciencesLaboratory of organic solidsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China

Supported metal catalysts are widely used in the modern chemical *** electronic interaction between supports and active components is of great significance for heterogeneous ***(GDY),a new type of carbon allotrope with sp-hybridized carbon atoms,πconjugate structure,and electron transmission capability,is a promising candidate as catalyst *** years have witnessed the rapid progress of GDY-supported metal catalysts for different catalysis *** that most processes in the current chemical industry are thermocatalytic reactions,we herein give an overview about the advances and particular characteristics of GDY-supported catalysts in these *** geometric structure and electronic properties of GDY are first ***,the synthesis methods for GDY-supported metal catalysts and their applications in thermocatalytic reactions are discussed,in which the effect of electronic interaction on catalytic performance is ***,the current challenges and future directions of GDY-supported metal catalysts for thermocatalysis are *** is expected that this review will enrich our understanding of the advances of GDY as a superior support for metal catalysts in thermocatalytic reactions.

关键词： graphdiyne metal catalysts thermocatalytic reactions heterogeneous catalysis

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Mapping Network-Coordinated Stacked Gated Recurrent Units for Turbulence Prediction

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IEEE/CAA Journal of Automatica Sinica 2024年第6期11卷 1331-1341页

作者： Zhiming Zhang Shangce Gao MengChu Zhou Mengtao Yan Shuyang cao Faculty of Engineering University of ToyamaToyama 930-8555Japan Helen and John C.Hartmann Department of Electrical and Computer Engineering New Jersey Institute of TechnologyNewark NJ 07102 USA Gaoling School of Artificial Intelligence Renmin University of ChinaBeijing 100872China College of Civil Engineering Tongji UniversityShanghai 200092China IEEE

Accurately predicting fluid forces acting on the sur-face of a structure is crucial in engineering ***,this task becomes particularly challenging in turbulent flow,due to the complex and irregular changes in the flow *** this study,we propose a novel deep learning method,named mapping net-work-coordinated stacked gated recurrent units(MSU),for pre-dicting pressure on a circular cylinder from velocity ***-cally,our coordinated learning strategy is designed to extract the most critical velocity point for prediction,a process that has not been explored *** our experiments,MSU extracts one point from a velocity field containing 121 points and utilizes this point to accurately predict 100 pressure points on the *** method significantly reduces the workload of data measure-ment in practical engineering *** experimental results demonstrate that MSU predictions are highly similar to the real turbulent data in both spatio-temporal and individual ***,the comparison results show that MSU predicts more precise results,even outperforming models that use all velocity field *** with state-of-the-art methods,MSU has an average improvement of more than 45%in various indicators such as root mean square error(RMSE).Through comprehensive and authoritative physical verification,we estab-lished that MSU’s prediction results closely align with pressure field data obtained in real turbulence *** confirmation underscores the considerable potential of MSU for practical applications in real engineering *** code is available at https://***/zhangzm0128/MSU.

关键词： Convolutional neural network deep learning recurrent neural network turbulence prediction wind load predic-tion.

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工作面回采过程沿空留巷非对称支护技术

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煤矿现代化 2023年第5期32卷 21-24页

作者：张毅曹蓓内蒙古汇能煤电集团有限公司内蒙古鄂尔多斯017000 鄂尔多斯职业学院内蒙古鄂尔多斯017000

为解决沿空留巷巷道支护困难问题,以新安煤矿8号煤层第3工作面运输巷沿空留巷为工程背景,利用FLAC^(3D)数值模拟对工作面回采过程中沿空留巷巷道围岩应力演化规律进行了研究,工作面回采过程中作用在充填体侧应力较大,作用在实体煤侧应... 详细信息

为解决沿空留巷巷道支护困难问题,以新安煤矿8号煤层第3工作面运输巷沿空留巷为工程背景,利用FLAC^(3D)数值模拟对工作面回采过程中沿空留巷巷道围岩应力演化规律进行了研究,工作面回采过程中作用在充填体侧应力较大,作用在实体煤侧应力较小。根据数值模拟结果,提出了“充填体+双排液压支柱+工字梁+高强度预应力锚索+高强度锚杆”的非对称支护技术,并成功应用于现场,有效地控制巷道围岩变形。

关键词：数值模拟沿空留巷非对称支护

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Non-volatile dynamically switchable color display via chalcogenide stepwise cavity resonators

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Opto-Electronic Advances 2024年第1期7卷 16-27页

作者： Kuan Liu Zhenyuan Lin Bing Han Minghui Hong Tun cao School of Optoelectronic Engineering and Instrumentation Science Dalian University of TechnologyDalian 116024China Pen-Tung Sah Institute of Micro-Nano Science and Technology Xiamen UniversityXiamen 361102China Institute of Laser Engineering Faculty of Materials and ManufacturingBeijing University of TechnologyBeijing 100124China

High-resolution multi-color printing relies upon pixelated optical nanostructures,which is crucial to promote color display by producing nonbleaching colors,yet requires simplicity in fabrication and dynamic *** trisulfide(Sb_(2)S_(3))is a newly rising chalcogenide material that possesses prompt and significant transition of its optical characteristics in the visible region between amorphous and crystalline phases,which holds the key to color-varying ***,we proposed a dynamically switchable color printing method using Sb_(2)S_(3)-based stepwise pixelated Fabry-Pérot(FP)cavities with various cavity *** device was fabricated by employing a direct laser patterning that is a less timeconsuming,more approachable,and low-cost *** switching the state of Sb_(2)S_(3) between amorphous and crystalline,the multi-color of stepwise pixelated FP cavities can be actively *** color variation is due to the profound change in the refractive index of Sb_(2)S_(3) over the visible spectrum during its phase ***,we directly fabricated sub-50 nm nano-grating on ultrathin Sb_(2)S_(3) laminate via microsphere 800-nm femtosecond laser irradiation in far *** minimum feature size can be further decreased down to~45 nm(λ/17)by varying the thickness of Sb_(2)S_(3) *** switchable Sb_(2)S_(3) photonic devices can take one step toward the next generation of inkless erasable papers or displays and enable information encryption,camouflaging surfaces,anticounterfeiting,***,our work explores the prospects of rapid and rewritable fabrication of periodic structures with nano-scale resolution and can serve as a guideline for further development of chalcogenide-based photonics components.

关键词： tunable color displays Fabry-Pérot cavity resonators color printing chalcogenide materials

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Weakly Polarized Organic Cation-Modified Hydrated Vanadium Oxides for High-Energy Efficiency Aqueous Zinc-Ion Batteries

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Nano-Micro Letters 2024年第7期16卷 169-186页

作者： Xiaoxiao Jia Chaofeng Liu Zhi Wang Di Huang Guozhong cao Department of Materials Science and Engineering University of WashingtonSeattleWA 98195USA School of Materials Science and Engineering Tongji UniversityShanghai 201804People’s Republic of China

Vanadium oxides,par-ticularly hydrated forms like V_(2)O_(5)·nH_(2)O(VOH),stand out as promising cathode candidates for aqueous zinc ion batteries due to their adjustable layered structure,unique electronic characteristics,and high theoretical ***,challenges such as vanadium dissolution,sluggish Zn^(2+)diffusion kinetics,and low operating voltage still hinder their direct *** this study,we present a novel vanadium oxide([C_(6)H_(6)N(CH_(3))_(3)]_(1.08)V_(8)O_(20)·0.06H_(2)O,TMPA-VOH),developed by pre-inserting trimethylphenylammonium(TMPA+)cations into *** incorporation of weakly polarized organic cations capitalizes on both ionic pre-intercalation and molecular pre-intercalation effects,resulting in a phase and morphology transition,an expansion of the interlayer distance,extrusion of weakly bonded interlayer water,and a substantial increase in V^(4+)*** modifications synergistically reduce the electrostatic interactions between Zn^(2+)and the V-O lattice,enhancing structural stability and reaction kinetics during *** a result,TMPA-VOH achieves an elevated open circuit voltage and operation voltage,exhibits a large specific capacity(451 mAh g^(-1)at 0.1 A g^(-1))coupled with high energy efficiency(89%),the significantly-reduced battery polarization,and outstanding rate capability and cycling *** concept introduced in this study holds great promise for the development of high-performance oxide-based energy storage materials.

关键词： Zinc-ion battery Vanadium oxide V_(2)O_(5)·nH_(2)O Pre-intercalation Interlayer engineering

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A Hybrid Air Quality Prediction Model Based on Empirical Mode Decomposition

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Tsinghua Science and Technology 2024年第1期29卷 99-111页

作者： Yuxuan cao Difei Zhang Shaoqi Ding Weiyi Zhong Chao Yan School of Computer Science Qufu Normal UniversityRizhao 276826China School of Mathematical Sciences Qufu Normal UniversityQufu 273165China School of Computer Science Qufu Normal UniversityRizhao 270826China College of Economic and Management Shandong University of Science and TechnologyQingdao 250307China

Air pollution is a severe environmental problem in urban *** air quality prediction can help governments and individuals make proper decisions to cope with potential air *** a classic time series forecasting model,the AutoRegressive Integrated Moving Average(ARIMA)has been widely adopted in air quality ***,because of the volatility of air quality and the lack of additional context information,i.e.,the spatial relationships among monitor stations,traditional ARIMA models suffer from unstable prediction *** some deep networks can achieve higher accuracy,a mass of training data,heavy computing,and time cost are *** this paper,we propose a hybrid model to simultaneously predict seven air pollution indicators from multiple monitoring *** proposed model consists of three components:(1)an extended ARIMA to predict matrix series of multiple air quality indicators from several adjacent monitoring stations;(2)the Empirical Mode Decomposition(EMD)to decompose the air quality time series data into multiple smooth sub-series;and(3)the truncated Singular Value Decomposition(SvD)to compress and denoise the expanded *** results on the public dataset show that our proposed model outperforms the state-of-art air quality forecasting models in both accuracy and time cost.

关键词： air quality prediction Empirical Mode Decomposition(EMD) Singular Value Decomposition(SVD) AutoRegressive Integrated Moving Average(ARIMA)

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