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A Multi-mode Electronic Load Sensing Control Scheme with Power Limitation and Pressure Cut-off for Mobile Machinery

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Chinese Journal of Mechanical Engineering 2023年第1期36卷 157-170页

作者： min cheng Bolin Sun Ruqi Ding Bing Xu State Key Laboratory of Mechanical Transmissions Chongqing UniversityChongqing400044China Key Laboratory of Conveyance and Equipment Ministry of EducationEast China Jiaotong UniversityNanchang330052China State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou310027China

In mobile machinery,hydro-mechanical pumps are increasingly replaced by electronically controlled pumps to improve the automation level,but diversified control functions(e.g.,power limitation and pressure cut-off)are integrated into the electronic controller only from the pump level,leading to the potential instability of the overall *** solve this problem,a multi-mode electrohydraulic load sensing(MELS)control scheme is proposed especially considering the switching stability from the system level,which includes four working modes of flow control,load sensing,power limitation,and pressure *** on the actual working requirements,the switching rules for the different modes and the switching direction(i.e.,the modes can be switched bilaterally or unilaterally)are *** priority of different modes is also defined,from high to low:pressure control,power limitation,load sensing,and flow *** multiple switching rules are satisfied at the same time,the system switches to the control mode with the highest *** addition,the switching stability between flow control and pressure control modes is analyzed,and the controller parameters that guarantee the switching stability are obtained.A comparative study is carried out based on a test rig with a 2-ton hydraulic *** results show that the MELS controller can achieve the control functions of proper flow supplement,power limitation,and pressure cut-off,which has good stability performance when switching between different control *** research proposes the MELS control method that realizes the stability of multi-mode switching of the hydraulic system of mobile machinery under different working conditions.

关键词： Hydraulic control Load sensing Multi-Mode Power limitation Mobile machinery

Laves Phase in 22Cr-27Ni-2Ti-Al Austenitic Valve Steel

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Journal of Iron and Steel Research International 2016年第12期23卷 1303-1308页

作者： Li-min WANG cheng-cheng XUE Gang YANG Zheng-dong LIU Institute for Special Steels Central Iron and Steel Research Institute Faculty of Materials Science and Engineering Kunming University of Science and Technology

The Thermo Calc software was employed to calculate the equilibrium phase of 22Cr-27Ni-2Ti-Al austenitic valve steel, and the Laves phase in this steel was investigated after solid solution and aging by means of scanning electron microscopy （SEM）, transmission electron microscopy （TEM） and X- ray diffraction （XRD）. Results show that the microstructure of the experimental steel consists of γ, γ′, Laves and NbC. *** phases mainly precipitate on grain boundaries, with granular and fibrous morphologies. The size of the granular Laves phase is about 50-600 nm, and the fihrous Laves phase is composed of short strip Laves phases which are 300-600 nm in length and 50 150 nm in width. These two morphologies of Laves phase coarsen with increasing aging temperature, and this steel possesses the highest strength and hardness at aging temperature of 760 ℃.

关键词： 22Cr-27Ni-2Ti A1 austenitic valve steel microstructure Laves phase aging

Rational offset approximation of rational Bézier curves

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第9期7卷 1561-1565页

作者： cheng min WANG Guo-jin Department of Mathematics Zhejiang University Hangzhou 310027 China Department of Mathematics Zhejiang University of Technology Hangzhou 310032 China

The problem of parametric speed approximation of a rational curve is raised in this paper. Offset curves are widely used in various applications. As for the reason that in most cases the offset curves do not preserve the same polynomial or rational polynomial representations, it arouses difficulty in applications. Thus approximation methods have been introduced to solve this problem. In this paper, it has been pointed out that the crux of offset curve approximation lies in the approximation of parametric speed. Based on the Jacobi polynomial approximation theory with endpoints interpolation, an algebraic rational approximation algorithm of offset curve, which preserves the direction of normal, is presented.

关键词： Rational Bézier curve Parametric speed Offset Rational approximation

Study of Two-Mode Squeezed Magnetopolarons

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Communications in Theoretical Physics 2007年第4期47卷 747-751页

作者： ZHANG Yan-min cheng Ze Department of Physics Huazhong University of Science and Technology Wuhan 430074 China

In this paper, we conduct an investigation into two-dimensional squeezed magnetopolarons. The Hamiltonian of magnetopolarons is dealt with two-mode squeezed states transformation, which is based on the Lee-Low-Pines and Huybrechts （LLP-H） canonical transformations. This method makes it possible to take account of the linear terms, bilinear ones of phonon operators, and the correlation between two longitudinal optical （LO） phonon modes. The energies of the ground state and excited states are evaluated by variational approach, and accurate results are obtained. Furthermore, the renormalized cyclotron masses for some possible transitions are discussed in detail.

关键词： magnetopolarons squeezed state electron-phonon interaction renormalized mass

A Reliable Neighbor-Based Method for Identifying Essential Proteins by Integrating Gene Expressions, Orthology,and Subcellular Localization Information

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Tsinghua Science and Technology 2016年第6期21卷 668-677页

作者： min Li Zhibei niu Xiaopei Chen Ping Zhong Fangxiang Wu Yi Pan the School of Information Science and Engineering Central South University the Department of Mechanical Engineering and Division of Biomedical Engineering University of Saskatchewan the Department of Computer Science Georgia State University

Essential proteins are those necessary for the survival or reproduction of species and discovering such essential proteins is fundamental for understanding the minimal requirements for cellular life, which is also meaningful to the disease study and drug design. With the development of high-throughput techniques, a large number of Protein-Protein Interactions（PPIs） can be used to identify essential proteins at the network level. Up to now, though a series of network-based computational methods have been proposed, it is still a challenge to improve the prediction precision as the high false positives in PPI networks. In this paper, we propose a new method GOS to identify essential proteins by integrating the Gene expressions, Orthology, and Subcellular localization *** gene expressions and subcellular localization information are used to determine whether a neighbor in the PPI network is reliable. Only reliable neighbors are considered when we analyze the topological characteristics of a protein in a PPI network. We also analyze the orthologous attributes of each protein to reflect its conservative features, and use a random walk model to integrate a protein＇s topological characteristics and its orthology. The experimental results on the yeast PPI network show that the proposed method GOS outperforms the ten existing methods DC, BC, CC, SC, EC, IC, NC, Pe C, ION, and CSC.

关键词： essential protein reliable neighbors GOS orthology subcellular localization information

Morphologic changes of simple star dunes during the growth process in Dunhuang,China

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Journal of Mountain Science 2022年第4期19卷 1095-1106页

作者： AN Zhi-shan ZHANG Ke-cun TAN Li-hai niu Qing-he LIU Ben-li niu Bai-cheng Dunhuang Gobi and Desert Research Station Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China Key Laboratory of Desert and Desertification Chinese Academy of SciencesLanzhou 730000China University of Chinese Academy of Sciences Beijing 100049China

Star dune is one typical kind of aeolian geomorphology in global sand *** has attracted scholars in various research fields for years because of its unique morphologic features like Egyptian *** landform pattern of star dune is mainly dominated by factors such as regional wind regime,sand availability,and local *** dunes grow vertically as they accumulate sand brought in from different directions;however,little is known regarding morphologic changes during this *** stability of star dunes based on quantitative data is another unsolved question due to the limitation in measuring equipment or other *** whether the star dune can grow into star sand hills is another scientific problem which needs to be *** this paper,the heightening development process and morphological changes of star dunes were monitored in mingsha Mountain of Dunhuang with the 3D laser *** show that the star dunes in mingsha Mountain were formed by a group of relatively steady winds,which were northwest,northeast and south *** the increase of the height of the star dunes,the morphological parameters of the dune,such as the volume and bottom area,did not show regular *** surface erosion of both Dune 1 and Dune 2 during the observation period was closely related to the regional wind *** the growth of the star dunes,the overall trend of the dunes was relatively steady and the dune shape maintained its stability although the aspect and slope of the sand dunes changed,indicating that the stability of star dune was not complete and was ***,the variation range of the dune slope was proportional to the volume change of the dune.

关键词： Star dune 3D laser scanner Dunhuang Morphologic change

Local events-based fast RTM surface-offset gathers via dip-guided interpolation

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Petroleum Science 2021年第3期18卷 773-782页

作者： Yang Zhao Feng-Lin niu Lei Fu cheng cheng Jin-Hong Chen Shou-Dong Huo State Key Laboratory of Petroleum Resources and Prospecting Unconventional Petroleum Research InstituteChina University of PetroleumBeijing 100083China Department of Earth Environmental and Planetary SciencesRice UniversityHoustonTXUSA Department of Earth and Planetary Science University of CaliforniaBerkeleyCAUSA Aramco Research Center Aramco Services CompanyHoustonTXUSA Institute of Geology and Geophysics Chinese Academy of SciencesBeijing 100029China

Reverse Time Migration(RTM)Surface Ofset Gathers(SOGs)are demonstrated to deliver more superior residual dip information than ray-based *** appears more powerful in complex geological settings,such as salt ***,the computational cost of constructing RTM SOGs is a big challenge in applying it to 3D feld *** tackle this challenge,we propose a novel method using dips of local events as a guide for RTM gather *** residual-dip information of the SOGs is created by connecting local events from depth-domain to time-domain via ray *** proposed method is validated by a synthetic experiment and a feld *** mitigates the computational cost by an order of magnitude while producing comparable results as fully computed RTM SOGs.

关键词： Surface-ofset gathers Reverse-time migration Dip-guided interpolation Reduced costs Local-event raytracing

Feasibility evaluation of failure models for predicting forming limit of metal foils

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Chinese Journal of Aeronautics 2020年第9期33卷 2461-2471页

作者： Bao MENG Jiejie SHI Yiyun ZHANG cheng cheng Bolin MA min WAN School of Mechanical Engineering and Automation Beihang UniversityBeijing 100083China

Forming limit of metal foil is an important index to evaluate its formability,and is of considerable significance to improve the quality of *** ductile fracture(DF)behavior in microscale plastic deformation is remarkably affected by the geometry and grain *** explore the size-dependent forming limit curve(FLC),the Holmberg and Marciniak tests of SUS304 foils with the thicknesses of less than 0.1 mm and diverse grain sizes were *** addition,the validity and feasibility of three types of existing failure models including Swift/Hill,MarciniakKuczynski(M-K)and DF criteria for predicting the micro-scaled FLCs were *** is found that the Swift/Hill model possesses the worst accuracy with predicting deviation above 50%.Four classical DF criteria including Freudenthal,Ayada,Brozzo and Oh show great difference,and Oh model considering plastic anisotropy presents the best *** predicted deviation of M-K model is aggravated with increasing grain size and decreasing foil thickness,which is attributed to the intensified free surface roughening and transformation of fracture mechanism with *** research thus provides a deeper understanding and valuable reference for the widespread application of FLC in microforming.

关键词： Failure criteria Forming limit Metal foil Microforming Size effect

Rational design of a hollow porous structure for enhancing diffusion kinetics of K ions in edge-nitrogen doped carbon nanorods

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Nano Research 2022年第9期15卷 8109-8117页

作者： Ping niu Yang Yang Zhiqiang Li Gaohui Ding Lingzhi Wei Ge Yao Helin niu Yulin min Fangcai Zheng Qianwang Chen Institutes of Physical Science and Information Technology Key Laboratory of Structure and Functional Regulation of Hybrid MaterialsAnhui UniversityMinistry of EducationHefei 230601China Hefei National Laboratory for Physical Science at Microscale and Department of Materials Science&Engineering University of Science and Technology of ChinaHefei 230026China Key Laboratory of Functional Inorganic Material Chemistry of Anhui Province Anhui UniversityHefei 230601China Shanghai Key Laboratory of Materials Protection and Advanced Materials Electric Power Shanghai Engineering Research Center of Energy-Saving in Heat Exchange SystemsShanghai University of Electric PowerShanghai 200090China

The high electrical conductivity makes it possible for one-dimensional(1D)carbon materials to be used as the promising anodes for potassium ion batteries(PIBs),however,the sluggish diffusion kinetics caused by large-sized potassium ions(K^(+))limits their practical applications in energy storage *** this work,hollow carbon nanorods were rationally designed as a case to verify the superiority of 1D hollow structure to improve the diffusion kinetics of K^(+).Simultaneously,edge-N(pyridinic-N and pyrrolic-N)atoms were also introduced into 1D hollow carbon structure,which can provide ample active sites and defects in graphitic lattices to adsorb K^(+),providing extra capacitive storage *** expected,the optimized edge-N doped hollow carbon nanorods(ENHCRs)exhibits a high reversible capacity of 544 mAh·g^(−1)at 0.1 A·g^(−1)after 200 *** at 5 A·g^(−1),it displays a long-term cycling stability with 255 mAh·g^(−1)over 10,000 *** electrochemical measurements confirm that the hollow structure is favorable to improve the transfer kinetics of K^(+)during *** the theoretical calculations demonstrate that edge-N doping can enhance the local electronegativity of graphitic lattices to adsorb much more K^(+),where edge-N doping synergizes with 1D hollow structure to achieve enhanced K^(+)-storage performances.

关键词： carbon materials edge-nitrogen hollow structure theoretical calculation batteries