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Stewart型并联机器人的奇异对其运动精度的影响

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机械制造与自动化 2024年第3期53卷 195-198,214页

作者：陈垚尤晶晶叶鹏达王澍声黄宁宁南京林业大学机械电子工程学院江苏南京210037 南京航空航天大学江苏省精密与微细制造技术重点实验室江苏南京210016 常州大学机械与轨道交通学院江苏常州213164

以9-3 Stewart型并联机器人为研究对象,分析其在机构接近奇异位形时动平台运动精度的情况。通过计算并联机器人速度Jacobian矩阵的行列式得到奇异点的坐标。通过虚拟样机实验,得到动平台参考点位置反解和正解计算的相对误差。用转动Jaco... 详细信息

以9-3 Stewart型并联机器人为研究对象,分析其在机构接近奇异位形时动平台运动精度的情况。通过计算并联机器人速度Jacobian矩阵的行列式得到奇异点的坐标。通过虚拟样机实验,得到动平台参考点位置反解和正解计算的相对误差。用转动Jacobian矩阵条件数的倒数来度量机构接近奇异的程度,并分析该程度与上述相对误差之间的映射关系。研究结果表明:当指标值大于7.027×10^(-5)时,正、反解的相对误差可忽略不计,这为奇异规避、路径规划等后续工作提供了理论参考。

关键词：并联机器人正解反解运动精度奇异位形 Jacobian矩阵

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Effects of uniconazole rate on agronomic traits and physiological indexes of rapeseed blanket seedling

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Oil Crop Science 2020年第4期5卷 198-204页

作者： Qingsong Zuo Long Wang Jingdong Zheng jingjing you Guang Yang Suohu Leng Jingyi Liu Jiangsu Key Laboratory of Crop Genetics and Physiology Yangzhou UniversityYangzhouChina Jiangsu Co-Innovation Center for Modern Production Technology of Grain Crops Yangzhou UniversityYangzhouChina Jiangsu Key Laboratory of Crop Cultivation and Physiology Yangzhou UniversityYangzhouChina

Mechanized transplanting of rapeseed(Brassica napus L.)blanket seedling is an innovative cultivation *** high quality blanket seedling to ensure high survival rate of seedling after transplanting is the key of the *** effects of different uniconazole rates of 0,0.5,1.0,1.5 and 2.0 mg/tray,spraying at one leaf and one heart stage,on selected agronomic traits,physiological indexes and survival rate of two rapeseed cultivars(‘Qinyou 100 and’Yangyou 90)were investigated in 2018 and *** results showed that the plant height decreased significantly with the increase of uniconazole ***,the collar diameter increased significantly with the increase of uniconazole rate up to 1.5 mg/tray,and the leaf area,dry weights of root and shoot increased with increased uniconazole rate up to 1.0 mg/*** root to shoot ratios,N concentrations of root and shoot with the uniconazole rates of 1.0 and 1.5 mg/tray were higher than those with other *** uniconazole rate increasing,gibberellin(GA)and auxin(IAA)concentrations of root and shoot decreased,while abscisic acid(ABA)concentrations increased,and cytokinin(CTK)concentrations topped at uniconazole rate of 1.0 mg/tray and decreased *** seedling survival rates with 1.0 and 1.5 mg/tray were greatly higher than those in other *** analysis suggested plant survival rate was positively related to CTK concentrations and negatively to GA concentrations of root and *** achieve high survival rate after mechanized transplanting,our study revealed that the uniconazole applied at a rate of 1.0 mg/tray was recommended as the best,followed by 1.5 mg/*** findings would help to enhance qualities of rapeseed blanket seedling and to promote popularization of mechanized transplanting of rapeseed production.

关键词： Rapeseed blanket seedling Mechanized transplanting Uniconazole rate Hormone concentration Survival rate

湖北广水—红安地区萤石矿成矿地质条件及找矿方向

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矿产勘查 2024年第5期15卷 794-802页

作者：周新尤静静邹院兵陈松杨年浩徐加林方洁湖北省地质局第六地质大队湖北孝感432000 资源与生态环境地质湖北省重点实验室湖北武汉430034

广水—红安地区萤石矿带是湖北省萤石矿重要的成矿区带之一,为找到新矿体,突破找矿中的关键性问题。通过野外调查及对区内萤石矿成矿地质背景、矿床地质特征、成矿地质条件、成矿规律的研究,认为该区萤石矿受区域性北西向深大断裂带控制... 详细信息

广水—红安地区萤石矿带是湖北省萤石矿重要的成矿区带之一,为找到新矿体,突破找矿中的关键性问题。通过野外调查及对区内萤石矿成矿地质背景、矿床地质特征、成矿地质条件、成矿规律的研究,认为该区萤石矿受区域性北西向深大断裂带控制,矿体、矿脉主要沿晚期叠加的北(北)东向断裂裂隙分布;赋矿围岩主要为红安岩群中含有大理岩、白云石英片岩的岩性组合;燕山期中酸性花岗岩与萤石矿成因关系最为密切。最直接的找矿标志为北(北)东向具硅化、重晶石化、萤石矿化等热液蚀变的断裂破碎带,已知矿床的深部、具矿化异常的相似构造破碎带和北西向新城—黄陂断裂带的次级构造带是主要的找矿方向。研究成果可为今后区内开展进一步的萤石矿勘查提供依据。

关键词：萤石矿矿床特征成矿地质条件找矿方向广水—红安湖北

大学图书馆面向年轻馆员的人才培养策略探析——以上海交通大学图书馆为例

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大学图书馆学报 2021年第3期39卷 34-39页

作者：尤晶晶上海交通大学图书馆上海200240

运用恰当、有效的策略吸引、培养和留住年轻馆员,是高校图书馆保持核心竞争力的关键。近十年来,就如何建设一支高素质的年轻馆员队伍,上海交通大学图书馆在人才招聘、岗位聘任、薪酬管理、职务晋升、馆员培训、国际交流和考核评估等方... 详细信息

运用恰当、有效的策略吸引、培养和留住年轻馆员,是高校图书馆保持核心竞争力的关键。近十年来,就如何建设一支高素质的年轻馆员队伍,上海交通大学图书馆在人才招聘、岗位聘任、薪酬管理、职务晋升、馆员培训、国际交流和考核评估等方面进行了系统性的探索,并就“十四五”期间大学图书馆如何培养年轻馆员人才队伍进行了思考。

关键词：大学图书馆人才培养上海交通大学馆员培训

Surrogate modeling for unsaturated infiltration via the physics and equality-constrained artificial neural networks

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第6期16卷 2282-2295页

作者： Peng Lan jingjing Su Sheng Zhang School of Civil Engineering Central South UniversityChangsha410075China Discipline of Civil Surveying and Environmental EngineeringPriority Research Centre for Geotechnical Science and EngineeringThe University of NewcastleCallaghanNSW2308Australia Qinghai University Qinghai810016China

Machine learning(ML)provides a new surrogate method for investigating groundwater flow dynamics in unsaturated *** pure data-driven methods(*** neural network,DNN)can provide rapid predictions,but they do require sufficient on-site data for accurate training,and lack interpretability to the physical processes within the *** this paper,we provide a physics and equalityconstrained artificial neural network(PECANN),to derive unsaturated infiltration solutions with a small amount of initial and boundary *** takes the physics-informed neural network(PINN)as a foundation,encodes the unsaturated infiltration physical laws(*** equation,RE)into the loss function,and uses the augmented Lagrangian method to constrain the learning process of the solutions of RE by adding stronger penalty for the initial and boundary *** unsaturated infiltration cases are designed to test the training performance of PECANN,***-dimensional(1D)steady-state unsaturated infiltration,1D transient-state infiltration,two-dimensional(2D)transient-state infiltration,and 1D coupled unsaturated infiltration and *** predicted results of PECANN are compared with the finite difference solutions or analytical *** results indicate that PECANN can accurately capture the variations of pressure head during the unsaturated infiltration,and present higher precision and robustness than DNN and *** is also revealed that PECANN can achieve the same accuracy as the finite difference method with fewer initial and boundary training ***,we investigate the effect of the hyperparameters of PECANN on solving RE *** provides an effective tool for simulating unsaturated infiltration.

关键词： Richards equation(RE) Unsaturated infiltration Data-driven solutions Numerical modeling Machine learning(ML)

HetNets Under Decoupled Uplink and Downlink Access with UE Random Discontinuous Transmission: Local Delay and Energy Efficiency

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China Communications 2024年第3期21卷 205-216页

作者： Zhang Yue Zheng Fuchun Luo jingjing School of Electronic and Information Engineering Harbin Institute of Technology(Shenzhen)Shenzhen 518055China

Due to the limited uplink capability in heterogeneousnetworks (HetNets), the decoupled uplinkand downlink access (DUDA) mode has recently beenproposed to improve the uplink performance. In thispaper, the random discontinuous transmission (DTX)at user equipment (UE) is adopted to reduce the interferencecorrelation across different time slots. By utilizingstochastic geometry, we analytically derive themean local delay and energy efficiency (EE) of an uplinkHetNet with UE random DTX scheme under theDUDA mode. These expressions are further approximatedas closed forms under reasonable *** results reveal that under the DUDA mode, there isan optimal EE with respect to mute probability underthe finite local delay constraint. In addition, with thesame finite mean local delay as under the coupled uplinkand downlink access (CUDA) mode, the HetNetsunder the DUDA mode can achieve a higher EE witha lower mute probability.

关键词： decoupled uplink and downlink access(DUDA) heterogeneous networks(HetNets) random discontinuous transmission(DTX) stochastic geometry

Calculation and Analysis of TVMS Considering Profile Shifts and Surface Wear Evolution Process of Spur Gear

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 136-150页

作者： Wenzheng Liu Rupeng Zhu Wenguang Zhou jingjing Wang College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjingChina

Profile shift is a highly effective technique for optimizing the performance of spur gear transmission ***,tooth surface wear is inevitable during gear meshing due to inadequate lubrication and long-term *** profile shift and tooth surface wear(TSW)can impact the meshing characteristics by altering the involute tooth *** this study,a tooth stiffness model of spur gears that incorporates profile shift,TSW,tooth deformation,tooth contact deformation,fillet-foundation deformation,and gear body structure coupling is *** model efficiently and accurately determines the time-varying mesh stiffness(TVMS).Additionally,an improved wear depth prediction method for spur gears is developed,which takes into consideration the mutually prime teeth numbers and more accurately reflects actual gear meshing *** show that consideration of the mutual prime of teeth numbers will have a certain impact on the TSW ***,the finite element method(FEM)is employed to accurately verify the values of TVMS and load sharing ratio(LSR)of profile-shifted gears and worn *** study quantitatively analyzes the effect of profile shift on the surface wear process,which suggests that gear profile shift can partially alleviate the negative effects of *** contribution of this study provides valuable insights into the design and maintenance of spur gear systems.

关键词： Profile shift Tooth surface wear Structure coupling effect Improved wear depth prediction method TVMS

Distributed user pairing and effective computation offloading in aerial edge networks

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Chinese Journal of Aeronautics 2024年第4期37卷 378-390页

作者： Wei LIANG Shuhui WEN Lixin LI jingjing CUI School of Electronics and Information Northwestern Polytechnical UniversityXi’an CN710072China The State Key Laboratory of Integrated Services Networks Xidian UniversityXi’an CN710126China School of Electronics and Computer Science University of SouthamptonSouthampton SO167NSUK

Future Sixth-Generation (6G) mobile communication networks extremely require the global connectivity and the ground Base Stations (BSs) are difficult to develop in some specific areas,such as mountainous ***,the aerial networks are the key framework for the future communications,in which the aerial vehicle could act as the access ***,Mobile Edge Computing (MEC) is also essential to enhance the data processing capabilities of aerial *** this paper,we study a comprehensive communication-computation resource management problem for jointly optimizing user pairing,power and time allocation in the MEC aided Cognitive Radio (CR) aerial networks,namely CR-MEC aerial ***,this multilevel optimization problem could be decomposed into the user pairing and power allocation as well as time allocation *** the conceived CR-MEC aerial networks,we propose a User Pairing and Computation Offloading Management Algorithm (UPCOMA) based on three-sided matching theory,aiming to minimize the system’s energy *** the first step of UPCOMA,multiple Primary Users (PUs) and Cognitive Users (CUs) on the ground negotiate to each other with the suitable power allocation coefficients and construct the stable user ***,the stable user pairs would match to a high altitude platform who act as the base station,which is for appropriately allocating Transmission Time Slots (TSs) at the second step of ***,a hybrid offloading mode is proposed in our conceived networks in order to support ground users to offload their tasks adaptively according to their individual ***,the simulation results reveal that the relative performance of UPCOMA is close to that of the Brute-Force Search Algorithm (BFSA) with low ***,the hybrid offloading mode with less energy consumption supports much more ground user pairs to offload tasks compared to the binary mode.

关键词： Aerial edge computing Binary offloading Cognitive radio Hybrid offloading Resource management

Optimizing hemicelluloses pre-extraction in eucalyptus kraft pulping:A pathway towards enhancing pulp mill biorefineries

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Chinese Journal of Chemical Engineering 2024年第6期70卷 162-172页

作者： Yuhan Wang Danqi Xue jingjing Zhuo Zhouyang Xiang State Key Laboratory of Pulp and Paper Engineering South China University of TechnologyGuangzhou 510640China

A critical pathway towards enhancing pulp mill biorefineries is to integrate the extraction and utilization of hemicelluloses into the pulping ***,an industrial pre-extraction strategy for hemicelluloses targeting eucalyptus kraft pulping process was *** solution or pulping white liquor was used to pre-extract hemicelluloses before the actual pulping *** response surface methodology(RSM)technique was applied to investigate the most suitable conditions to maximize the yield of these hemicelluloses while simultaneously minimizing the damage to pulp yields and ***(105 to 155℃),alkali concentration(3%to 8%),sulfidity(20%to 30%)and retention time(19 to 221 min)were combined to evaluate their effects on hemicellulose yields and chemical *** optimal pre-extraction conditions identified in this work(5.75%NaOH concentration,25%sulfidity at 135℃for 60 min)successfully allowed recovering 4.8%of hemicelluloses(based on the wood dry mass)and limited damages to pulp yields and *** cellulose content in pulp can even be increased by about 10%.Hemicellulose emulsification properties were also evaluated,which were comparable to synthetic *** study provides an industrial pathway to effectively separate and utilize wood hemicelluloses from the pulping process,which has the potential to improve the economy and material utilization of pulp and paper mills.

关键词： Hemicelluloses Xylan Pre-extraction Kraft pulping Emulsifying Response surface methodology(RSM)