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A Hydraulic Performance Comparison of Centrifugal Pump Operating in Pump and Turbine Modes

Journal of Thermal Science 2020年第6期29卷 1594-1605页

作者： DAI Cui DONG Liang LIN Haibo zhao fei School of Energy and Power Engineering Jiangsu UniversityZhenjiang 212013China Sichuan Provincial Key Lab of Process Equipment and Control Sichuan University of Science&EngineeringZigong 643000China Research Center of Fluid Machinery Engineering and Technology Jiangsu UniversityZhenjiang 212013China School of Mechanical Research Center of Technology Wuxi Institute of TechnologyWuxi 214121China

The modifications of impeller may show diverse impact on centrifugal pump operating in pump and turbine *** clarify this problem,the hydraulic performance of a low specific speed centrifugal pump operating in both modes was firstly obtained by CFD method and verified by ***,based on the single-factor design method,a series of calculations have been conducted to identify the effects of impeller geometry parameters on the hydraulic performance in different *** variations of head,shaft power and hydraulic efficiency curves with different impeller parameters were *** is found that compared with turbine,the pump shows a more obvious variation of *** outlet angle has positive impact both on the head consumed by pump or generated by *** change of turbine shaft power is apparently smaller than that of pump for different impeller geometry *** the outlet width somewhat changes the turbine shaft *** hydraulic efficiency in both modes shows different variation under different impeller geometric parameters,while the hydraulic efficiency of both modes is reduced with the outlet angle ***,the response amount of hydraulic efficiency caused by certain change of impeller parameters was estimated by sensitivity analysis *** is found that only the appropriate blade number and outlet width can improve the hydraulic performance both in pump and turbine ***,the hydraulic loss,skin friction loss and theoretical analysis were performed to explore the reason of hydraulic performance variation due to different impeller *** change of slip factor,impeller inlet area,impeller outlet area or hydraulic loss results in the change of hydraulic performance in both *** results can be useful for hydraulic performance improvement for both pump and turbine modes through impeller geometry modification.

关键词： Computational Fluid Dynamics centrifugal pump impeller modification pump mode turbine mode

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Extended DMPs Framework for Position and Decoupled Quaternion Learning and Generalization

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Chinese Journal of Mechanical Engineering 2022年第4期35卷 227-239页

作者： Zhiwei Liao fei zhao Gedong Jiang Xuesong Mei State Key Laboratory for Manufacturing System Engineering Xi’an Jiaotong UniversityXi’an 710049China Shaanxi Key Laboratory of Intelligent Robots and School of Mechanical Engineering Xi’an Jiaotong UniversityXi’an 710049China

Dynamic movement primitives(DMPs)as a robust and efcient framework has been studied widely for robot learning from *** DMPs framework mainly focuses on the movement learning in Cartesian or joint space,and can’t properly represent end-efector *** this paper,we present an extended DMPs framework(EDMPs)both in Cartesian space and 2-Dimensional(2D)sphere manifold for Quaternion-based orientation learning and *** mixture model and Gaussian mixture regression(GMM-GMR)are adopted as the initialization phase of EDMPs to handle multi-demonstrations and obtain their mean and ***,some evaluation indicators including reachability and similarity are defned to characterize the learning and generalization abilities of ***,a real-world experiment was conducted with human demonstrations,the endpoint poses of human arm were recorded and successfully transferred from human to the *** experimental results show that the absolute errors of the Cartesian and Riemannian space skills are less than 3.5 mm and 1.0°,*** Pearson’s correlation coefcients of the Cartesian and Riemannian space skills are mostly greater than *** developed EDMPs exhibits superior reachability and similarity for the multi-space skills’learning and *** research proposes a fused framework with EDMPs and GMM-GMR which has sufcient capability to handle the multi-space skills in multi-demonstrations.

关键词： Learning from demonstration Dynamic movement primitives 2D sphere manifold Gaussian mixture model Gaussian mixture regression Quaternion-based orientation

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A Fusion Kalman Filter and UFIR Estimator Using the Influence Function Method

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IEEE/CAA Journal of Automatica Sinica 2022年第4期9卷 709-718页

作者： Wei Xue Xiaoli Luan Shunyi zhao fei Liu IEEE the Key Laboratory of Advanced Process Control for Light Industry(Ministry of Education) Institute of AutomationJiangnan University

In this paper,the Kalman filter(KF)and the unbiased finite impulse response(UFIR)filter are fused in the discrete-time state-space to improve robustness against *** avoid the problem where fusion filters may give up some advantages of UFIR filters by fusing based on noise statistics,we attempt to find a way to fuse without using noise *** fusion filtering algorithm is derived using the influence function that provides a quantified measure for disturbances on the resulting filtering outputs and is termed as an influence finite impulse response(IFIR)*** main advantage of the proposed method is that the noise statistics of process noise and measurement noise are no longer required in the fusion process,showing that a critical feature of the UFIR filter is *** numerical example and a practice-oriented case are given to illustrate the effectiveness of the proposed *** is shown that the IFIR filter has adaptive performance and can automatically switch from the Kalman estimate to the UFIR estimates according to operating ***,the proposed method can reduce the effects of optimal horizon length on the UFIR estimate and can give the state estimates of best accuracy among all the compared methods.

关键词： Fusion filter influence function Kalman filter(KF) robustness unbiased finite impulse response(FIR)

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Systematics on production of superheavy nuclei Z=119-122 in fusion-evaporation reactions

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Nuclear Science and Techniques 2021年第10期32卷 59-71页

作者： fei Niu Peng-Hui Chen zhao-Qing Feng School of Physics and Optoelectronic Technology South China University of TechnologyGuangzhou 510640China College of Electrical Energy and Power Engineering Yangzhou UniversityYangzhou 225000China

The fusion dynamics of the formation of super-heavy nuclei were investigated thoroughly within the din-uclear system *** Monte Carlo approach was implemented in the nucleon transfer process to include all possible orientations,at which the dinuclear system is assumed to be formed at the touching configuration of dinuclear *** production cross sections of superheavy nuclei Cn,Fl,Lv,Ts,and Og were calculated and compared with the available data from *** evaporation residue excitation functions in the channels of pure neutrons and charged particles were systematically *** combinations of 44 Sc,48;50 Ti,49;51 V,52;54 Cr,58;62 Fe,and 62;64 Ni bombarding the actinide nuclides 238 U,244 Pu,248 Cm,247;249 Bk,249;251 Cf,252 Es,and 243 Am were calculated to produce the superheavy elements with Z¼119?*** obtained that the production cross sections sensitively depend on the neutron richness of the reaction *** structure of the evaporation residue excitation function is related to the neutron separation energy and fission barrier of the compound nucleus.

关键词： Dinuclear system model Fusion-evaporation reactions Superheavy nuclei Cross sections

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Reduction of unactivated alkyl chlorides enabled by light-induced single electron transfer

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Science China Chemistry 2024年第2期67卷 471-481页

作者： Lei Dai zhao-fei Zhang Xiang-Yu Chen School of Chemical Sciences University of the Chinese Academy of SciencesBeijing100049China Institute of Chemistry Chinese Academy of SciencesBeijing100190China Binzhou Institute of Technology Weiqiao-UCAS Science and Technology ParkBinzhou256606China

Alkyl chlorides are abundant and easily accessible starting ***,due to the high reduction potentials associated with unactivated alkyl chlorides,achieving their single electron reduction remains a persistent *** challenge has spurred the exploration of efficient activation methods to overcome this *** recent years,photocatalysis has emerged as a mild and potent tool for the single electron reduction of unactivated alkyl chlorides,opening up new possibilities in this *** the rapid advancements in this area,a comprehensive review that provides a conceptual understanding of this emerging field,with a specific focus on reaction design and catalytic mechanisms,would be timely and highly ***,we present an overview of various synthetic techniques for photoinduced single electron reduction of unactivated alkyl ***,we also discuss the limitations of the present methods and future directions that lie ahead in this field.

关键词： photocatalysis unactivated alkyl chlorides single electron transfer radical reactions

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Bayesian Filtering for High-Dimensional State-Space Models With State Partition and Error Compensation

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1239-1249页

作者： Ke Li Shunyi zhao Biao Huang fei Liu Key Laboratory of Advanced Process Control for Light Industry(Ministry of Education) Institute of AutomationJiangnan UniversityWuxi 214122China Department of Chemical and Materials Engineering University of AlbertaEdmonton AB T6G 2G6Canada

In the era of exponential growth of data availability,the architecture of systems has a trend toward high dimensionality,and directly exploiting holistic information for state inference is not always computationally *** paper proposes a novel Bayesian filtering algorithm that considers algorithmic computational cost and estimation accuracy for high-dimensional linear *** high-dimensional state vector is divided into several blocks to save computation resources by avoiding the calculation of error covariance with immense *** that,two sequential states are estimated simultaneously by introducing an auxiliary variable in the new probability space,mitigating the performance degradation caused by state ***,the computational cost and error covariance of the proposed algorithm are analyzed analytically to show its distinct features compared with several existing *** results illustrate that the proposed Bayesian filtering can maintain a higher estimation accuracy with reasonable computational cost when applied to high-dimensional linear systems.

关键词： filtering estimation error

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Dynamic recrystallization behaviour of H13-mod steel

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Journal of Iron and Steel Research International 2020年第9期27卷 1073-1086页

作者： Chang-min Li Yuan-biao Tan fei zhao College of Materials and Metallurgy Guizhou UniversityGuiyang 550025GuizhouChina

H13-mod steel developed after optimizing the composition and heat treatment process exhibits good hardness and impact toughness and can be used as a shield machine *** on the Avrami equation,the dynamic recrystallization(DRX)behaviour of H13-mod steel during hot compression was studied in the temperature of 900-1150°C and strain rate ranges of 0.01-10 s^-1.A DRX model and finite element software were used to study DRX behaviour of H13-mod *** DRX was found at both low and high strain *** backscatter diffraction and optical microscopy analyses found different DRX nucleation mechanisms at low and high strain rates under different *** a low strain rate,the nucleation was dominated by the strain-induced grain boundary migration,whereas the subgrain coalescence mechanism was dominant at a high strain ***,dynamic recovery occurred in both *** addition,it was easier to obtain small and uniform equiaxed grains at high strain rates than at low strain rates.

关键词： H13-mod steel Dynamic recrystallization Dynamic recrystallization volume fraction model Finite element simulation Nucleation mechanism

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L^(2)Schrödinger Maximal Estimates Associated with Finite Type Phases in R^(2)

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Acta Mathematica Sinica,English Series 2024年第11期40卷 2809-2839页

作者： Zhuo Ran LI Jun Yan zhao Teng fei zhao Department of Mathematics Taizhou UniversityTaizhou225300P.R.China School of Mathematical Sciences Zhejiang Normal UniversityJinhua321004P.R.China School of Mathematics and Physics University of Science and Technology BeijingBeijing100083P.R.China

In this paper,we establish Schrödinger maximal estimates associated with the finite type phaseФ(ξ_(1),ξ_(2)):=ξ_(1)^(m)+ξ_(2)^(m),where m≥4 is an even ***[12],we prove an L2 fractal restriction estimate associated with the surface{(ξ_(1),ξ_(2),Ф(ξ_(1),ξ_(2))):(ξ_(1),ξ_(2)∈[0,]^(2)}as the main result,which also gives results on the average Fourier decay of fractal measures associated with these *** key ingredients of the proof include the rescaling technique from[16],Bourgain-Demeter’sℓ^(2)decoupling inequality,the reduction of dimension arguments from[17]and induction on *** notice that our Theorem 1.1 has some similarities with the results in[8].However,their results do not cover *** arguments depend on the positive definiteness of the Hessian matrix of the phase function,while our phase functions are degenerate.

关键词： Pointwise convergence finite type decoupling reduction of dimension arguments

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Mechanical properties and microstructure of multilayer graphene oxide cement mortar

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Frontiers of Structural and Civil Engineering 2021年第4期15卷 1058-1070页

作者： Jun LIU Luxi zhao fei CHANG Lin CHI School of Environment and Architecture University of Shanghai for Science and TechnologyShanghai200093China

This study reports on the effects of multilayer graphene oxide(MGO)on compressive strength,flexural strength,and microstructure of cement *** cement mortar was prepared with type ***.52.5 Portland cement,standard sand,and *** mixes were prepared with inclusion of MGO(0%,0.02%,0.04%,and 0.06%by weight of cement).The testing result shows that the compressive of GO-cement mortar increased by 4.84%–13.42%,and the flexural strength increased by 4.37%–8.28%at 3 ***-cement mortar’s compressive strength and flexural strength at 7 d increased by 3.84%–12.08%and 2.54%–13.43%,*** made little contribution to the increases of compressive strength and flexural strength of cement mortar at 28 *** results of X-ray diffraction(XRD),scanning electron microscope(SEM),and nitrogen(N2)adsorption/desorption tests show that the types of hydration products and crystal grain size did not change after adding ***,it can help to improve the microstructure of the cement mortar via regulating hydration products and can provide more condensed cores to accelerate ***,the regulating action of MGO for the microstructure of cement mortar at an early age was better than that at 28 d.

关键词： graphene oxide cement mortar mechanical properties microstructure

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Global Tool Path Fairing Algorithm for Automated Fiber Placement

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Transactions of Nanjing University of Aeronautics and Astronautics 2018年第3期35卷 539-546页

作者： Wang Xianfeng Ye Ziheng Wang Ruozhou zhao cong R&D Center for Composites Industry Automation Nanjing University of Aeronautics and Astronautics

A global energy fairing method,applied to automated fiber placement(AFP)tool path,was *** main purpose was to improve the adaptability of AFP path towards part with sharp curvature variation as well as product *** relation between path geometric property and manufacturing property was discussed and a series of experiments were carried *** on cubic B-Spline global fairing method,the AFP tool path was faired which decreased the tool path curvature and curvature changing *** with initial ones,the path faired by the proposed method was relatively flat and smooth,which contributed to layup efficiency and reducing bulking *** method was demonstrated potentials in application for AFP manufacturing,especially for aeronautic and aerospace industry practice.

关键词： automated fiber placement(AFP) tool path fairing fiber steering manufacturing

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