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Dynamic modeling and analysis of the 3-PRS power head based on the screw theory and rigid multipoint constraints

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Science China(Technological Sciences) 2023年第7期66卷 1869-1882页

作者： MA YiWei TIAN yanling liu XianPing LU ChengHao School of Engineering The University of WarwickCoventryCV47ALUK School of Mechanical Engineering Tianjin UniversityTianjin300072China

This study presents a dynamic modeling and analysis methodology for the 3-PRS parallel mechanism.First,an improved reduced dynamic model of component substructures is proposed using the dynamic condensation technique and the rigid multipoint constraints at the joint/interface level,leading to a minimum set of generalized coordinates for external nodes.Next,the mapping between interface constraint stiffness and global stiffness is illustrated,resulting in an analytical stiffness model of joint substructures.Subsequently,the derived component and joint substructures are synthesized into the entire mechanism based on the Lagrange equation.Finally,a case study illustrates that the lower-order dynamic performances predicted within the proposed approach have the same trend as those obtained from a complete-order finite element model.The root mean square discrepancy of the lower-order natural frequencies between the two models is less than 5.92%,indicating the accuracy and effectiveness of the proposed model.The developed approach can highly and efficiently predict the dynamic performance distributions across the entire workspace and guide the optimal functional design under the virtual machine framework.

关键词： dynamic modeling parallel kinematic machines screw theory substructure synthesis rigid multipoint constraints

Effects of paclobutrazol application on plant architecture,lodging resistance,photosynthetic characteristics,and peanut yield at different single-seed precise sowing densities

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The Crop Journal 2023年第1期11卷 301-310页

作者： Jihao Zhao Huajiang Lai Chen Bi Mengjie Zhao Yanling liu Xiangdong Li Dongqing Yang State Key Laboratory of Crop Biology Agronomy College of Shandong Agricultural UniversityTai’an 271018ShandongChina

The key to high-yielding peanut cultivation is the optimization of agricultural production practices.Regulating single-seed precise sowing(SSPS)density and paclobutrazol(Pbz)application concentration are effective practices that increase peanut yield by improving plant architecture,lodging resistance,and photosynthetic characteristics.Therefore,we conducted a two-factor field optimization experiment for the sowing density(D1:1.95×10^(5)plants ha^(-1),D52:2.40×10plants ha^(-1),D3:2.85×10^(5)plants ha^(-1),and D4:3.30×10^(5)plants ha^(-1))and Pbzapplication concentration(P0:0 mg L^(-1)and P1:100 mg L^(-1)).The objective was to optimize agricultural production practices and provide a theoretical basis for highyielding peanut cultivation by evaluating the effects of sowing density and Pbzapplication on plant architecture,lodging resistance,photosynthetic characteristics,and yield.The results showed that at the same Pbzapplication concentration,increasing sowing density increased lodging percentage and reduced leaf photosynthetic capacity.At the same sowing density,Pbzapplication reduced lodging percentage by decreasing plant height(PH),improving lignin biosynthesis-related enzyme activities,and enhancing stem puncture strength(SPS)and breaking strength(SBS).The paclobutrazol-induced alterations in plant architecture and lodging resistance improved light transmission at the middle and bottom leaf strata,resulting in the increase in relative chlorophyll content and net photosynthetic rate(Pn)of leaves.Furthermore,D3P1treatment had the highest peanut yield among all treatments.In summary,the production strategy combining the sowing density of 2.85×10^(5)plants ha^(-1)with the application of100 mg L^(-1)Pbzwas found to be the optimal agricultural production practice for giving full play to production potential and achieving higher peanut yield.

关键词： Sowing density Paclobutrazol application Lodging resistance Photosynthetic characteristics Peanut yield

A Control Algorithm for the Optimization of Batch Reactor-Based Processes

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Fluid Dynamics & Materials Processing 2019年第4期15卷 307-319页

作者： yanling Bai Feng liu Artificial Intelligence Institute Zhengzhou Railway Vocational&Technical CollegeZhengzhouChina Cyber Security Guard Henan Provincial Public Security DepartmentZhengzhouChina

Levenberg-Marquardt(LM)algorithm is applied for the optimization of the heat transfer of a batch reactor.The validity of the approach is verified through comparison with experimental results.It is found that the mathematical model can properly describe the heat transfer relationships characterizing the considered system,with the error being kept within±2℃.Indeed,the difference between the actual measured values and the model calculated value curve is within±1.5℃,which is in agreement with the model assumptions and demonstrates the reliability and effectiveness of the algorithm applied to the batch reactor heat transfer model.Therefore,the present work provides a theoretical reference for the conversion of practical problems in the field of chemical production into mathematical models.

关键词： Batch reactor LM algorithm parameter estimation model

Semi-analytical Stiffness Model of Bolted Joints in Machine Tools Considering the Coupling Effect

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Nanomanufacturing and Metrology 2023年第2期6卷 66-78页

作者： Yiwei Ma Yutao Fu yanling Tian Xianping liu School of Engineering The University of WarwickCoventry CV47ALUK School of Mechanical Engineering Tianjin UniversityTianjin 300072China

This study proposes an improved semi-analytical approach for contact stiffness modeling of bolted joints in a machine tool system.First,nonlinear contact stress distribution within a single-bolted joint is obtained from the simulation results of finite element analysis software.Second,employing the Hertz contact theory and fractal theory,the contact stiffness model of a single asperity is formulated,affording analytical expressions for normal and tangential contact stiffnesses of a single-bolted joint by integrating multi-asperities in the contact area.Subsequently,considering two test specimens as illustrations,the mode shapes and natural frequencies of the proposed model and modal analysis tests are compared,and the influence of coupling effects between two adjacent bolts is illustrated.The maximum error in the natural frequencies of the proposed approach is<2.73%relative to the experimental results.Finally,the measurements of frequency response functions on a box-in-box precision horizontal machine tool are conducted to demonstrate the accuracy and efficiency of the proposed model.The proposed model is highly efficient in revealing the influence of microcontact factors on the contact stiffness of bolted joints and in guiding the optimal functional design of bolt arrangements under the framework of virtual machine tools.

关键词： Stiffness modeling Bolted joint Microcontact mechanics Fractal theory Rough surface

Microtubules composed of α4A undergo curved growth mainly mediated by its core structure

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分子细胞生物学报:英文版 2023年第1期15卷 58-61页

作者： Lei Diao Mingyi liu Yanling liu Xu Zhang Lan Bao State Key Laboratory of Cell Biology Shanghai Institute of Biochemistry and Cell BiologyCenter for Excellence in Molecular Cell ScienceUniversity of Chinese Academy of SciencesChinese Academy of SciencesShanghai 200031China School of Life Science and Technology ShanghaiTech UniversityShanghai 201210China Shanghai Advanced Research Institute Chinese Academy of SciencesShanghai 201210China Guangdong Institute of Intelligence Science and Technology HengqinZhuhai 519031China

Dear Editor,Microtubules consisting of α/β-tubulin dimers exhibit various shapes in different cell stages and cell types,which are important for their diverse roles in eukaryotic cells.Both α-and β-tubulin comprise multiple genes in vertebrates,e.***.mice have at least seven α-tubulin and eight β-tubulin genes.The distribution and expression of these isotypes vary widely among different tissues and developmental stages.Tubulin α1A is generally expressed in post-mitotic neurons and exhibits a decrease in postnatal and adult stages(Yue et al.,2014),while tubulin α4A is highly expressed in the brain and heart during later stages of development(Yue et al.,2014).

关键词： al. curved Microtubule

NONPARAMETRIC REGRESSION UNDER DOUBLE-SAMPLING DESIGNS

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Journal of Systems Science & Complexity 2011年第1期24卷 167-175页

作者： Xuejun JIANG Jiancheng JIANG Yanling liu School of Mathematical Sciences Peking University Beijing 100871 China School of Statistics and Mathematics Zhongnan University of Economics and Law Wuhan 430073China Department of Mathematics and Statistics University of North Carolina Charlotte North Carolina 28223 USA School of Mathematical Sciences Peking University Beijing 100871 China

这份报纸在双采样图案下面与代理人结果数据学习回归函数的 nonparametric 评价，在代理回答被观察因为完整的样品和真反应在一个确认集合上被观察的地方。一条新评价途径为估计回归功能被建议。作者首先用基于确认 subsample 更光滑的... 详细信息

这份报纸在双采样图案下面与代理人结果数据学习回归函数的 nonparametric 评价，在代理回答被观察因为完整的样品和真反应在一个确认集合上被观察的地方。一条新评价途径为估计回归功能被建议。作者首先用基于确认 subsample 更光滑的一个核估计回归功能，然后由从完整的样品从非确认 subsample 和反应的代理人在不完全的观察上利用信息改进评价。建议评估者的 Asymptotic 规度被导出。建议方法的有效性经由模拟被表明。

关键词：抽样设计非参数回归回归函数估计非参数估计全样本估计方法不完全性渐近正态

High-performance bulk heterojunction-based photocathode with facile architecture for photoelectrochemical water splitting

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Chinese Chemical Letters 2023年第1期34卷 182-186页

作者： yanling Wu Deyu liu Huanglong Zhuang Jiabo Le Yongbo Kuang Ningbo Institute of Materials Technology and Engineering Chinese Academy of SciencesNingbo 315201China University of Chinese Academy of Sciences Beijing 100049China Fujian Provincial Key Laboratory of Featured Biochemical and Chemical Materials Ningde Normal UniversityNingde 352100China

Organic semiconductors are promising candidates as photoactive layers for photoelectrodes used in photoelectrochemical(PEC)cells due to their excellent light absorption and efficient charge transport properties with the help of interfacial materials.However,the use of multilayers will make the charge transfer mechanism more complicated and decrease the PEC performance of the photoelectrode caused by the increased contact resistance.In this work,a PM6:Y6 bulk heterojunction(BHJ)-based photocathode is fabricated for efficient PEC hydrogen evolution reaction(HER)in an acidic aqueous solution.With RuO_(2)as an interfacial modification layer,the photocathode with a simple structure(fluorine-doped tin oxide(FTO)/PM6:Y6/RuO_(2))generates a maximum photocurrent density up to-15 m A/cm^(2)at 0 V vs.reference hydrogen electrode(RHE),outperforming all previously reported BHJ-based photocathodes in terms of PEC performance.The highest ratiometric power-saved efficiency of 3.7%is achieved at 0.4 V vs.RHE.

关键词： Photocathodes Ruthenium oxide Bulk heterojunctions Hydrogen evolution Photoelectrochemical cells

One-step post-treatment boosts thermoelectric properties of PEDOT:PSS flexible thin films

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Journal of Materials Science & Technology 2023年第1期132卷 81-89页

作者： Xingyu liu Xiao-Lei Shi Li Zhang Wei-Di liu yanling Yang Zhi-Gang Chen School of Materials Science and Engineering Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic MaterialsShaanxi University of Science and TechnologyXi’an 710021China School of Chemistry and Physics Queensland University of TechnologyBrisbaneQLD 4000Australia Australian Institute for Bioengineering and Nanotechnology The University of QueenslandBrisbaneQLD 4072Australia

Developing high-performance poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate)(PEDOT:PSS)sig-nificantly widens the practical applications of flexible organic thermoelectric devices,while the water-based co-solvent dopants and/or post-treatments are still rarely studied so far.Here,we develop a one-step post-treatment to improve the power factor of PEDOT:PSS films by using a water-based solution,which is composed of co-solvent(polar solvent dimethylacetamide(DMAC)and deionized water)and organic reducing agent L-ascorbic acid(LAA).The 80 vol.%DMAC solution significantly boosts the room-temperature electrical conductivity of the films from 5 to 964 S cm^(−1),while the Seebeck coefficient can be further enhanced from 18.7 to 25μV K−1 by treating with 0.5 mol L−1 LAA,contributing to a sig-nificantly improved power factor of 55.3μW m^(−1)K^(−2).The boosted electrical conductivity is ascribed to the separated PEDOT and PSS phases triggered by the high dielectric constant and polarity of DMAC;while the improved Seebeck coefficient is attributed to the reduced oxidation degree of PEDOT from the reducing agent LAA,both confirmed by the comprehensive structural and morphological characteri-zations.Furthermore,a maximum power factor of 64.4μW m^(−1)K^(−2)can be achieved at 360 K and the observed temperature-dependent electrical transport behavior can be well explained by the Mott variable range hopping model.Besides,a flexible thermoelectric device,assembled by the as-fabricated PEDOT:PSS films,exhibits a maximum output power of∼23 nW at a temperature difference of 25 K,indicating the potential for applying to low-grade wearable electronics.

关键词： Thermoelectric PEDOT:PSS Post-treatment Dimethylacetamide L-ascorbic acid

Synergistically assembled RGO/Si_(3)N_(4) whiskers hybrid aerogels to endow epoxy composites with excellent thermal and tribological performance

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摩擦:英文版 2023年第11期11卷 2091-2106页

作者： Yongjun ZHOU Yuanya ZHANG Meng liu yanling WANG Junya YUAN Xuehu MEN School of Materials and Energy Lanzhou UniversityLanzhou 730000China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China Center of Materials Science and Optoelectronics Engineering University of Chinese Academy of SciencesBeijing 100049China

Epoxy resin(EP)composites with satisfactory thermal and tribological performance are highly required for engineering moving components.However,the simple addition of fillers leaded to the serious filler agglomeration and limited promotion in tribological properties.In this work,we constructed a new kind of three-dimensional(3D)reduced graphene oxide(RGO)/Si_(3)N_(4) hybrid aerogel for EP composites,which was prepared by a facile hydrothermal self-assembly method followed by freeze-drying technique.As a result,the dispersibility of Si_(3)N_(4) whiskers was greatly improved through wrapping of polydopamine–polyethyleneimine copolymer(PDA–PEI)copolymer and physical spacing of 3D skeleton.Furthermore,benefiting from the synergistic effect of RGO and Si_(3)N_(4)@PDA–PEI in the thermal network,the thermal conductivity of RGO/Si_(3)N_(4) hybrid aerogel(GSiA)–EP increased by 45.4%compared to that of the neat EP.In addition,the friction coefficient and wear rate of GSiA–EP decreased by 83.7%and 35.8%,respectively.This work is significant for opening a tribological performance enhancement strategy though constructing 3D hybrid architecture.

关键词： three-dimensional(3D)hybrid structure reduced graphene oxide(RGO)/Si_(3)N_(4)hybrid aerogel thermal properties tribological properties wear mechanism synergistic effect