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Research on cubic polynomial acceleration and deceleration control model for high speed NC machining

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第3期9卷 358-365页

作者： hong-bin LENG Yi-jie WU Xiao-hong pan Institute of Modern Manufacture Engineering Zhejiang University Hangzhou 310027 China

To satisfy the need of high speed NC (numerical control) machining, an acceleration and deceleration (acc/dec) control model is proposed, and the speed curve is also constructed by the cubic polynomial. The proposed control model provides continuity of acceleration, which avoids the intense vibration in high speed NC machining. Based on the discrete characteristic of the data sampling interpolation, the acc/dec control discrete mathematical model is also set up and the discrete expression of the theoretical deceleration length is obtained furthermore. Aiming at the question of hardly predetermining the deceleration point in acc/dec control before interpolation, the adaptive acc/dec control algorithm is deduced from the expressions of the theoretical deceleration length. The experimental result proves that the acc/dec control model has the characteristic of easy implementation, stable movement and low impact. The model has been applied in multi-axes high speed micro fabrication machining successfully.

关键词： High speed NC machining Acceleration and deceleration (acc/dec) control model Cubic speed curve Discrete mathematical model Adaptive acceleration and deceleration control algorithm

Pressure fluctuation signal analysis of pump based on ensemble empirical mode decomposition method

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Water Science and Engineering 2014年第2期7卷 227-235页

作者： hong pan Min-sheng BU College of Energy and Electrical Engineering Hohai University College of Mechanical and Electrical Engineering Hohai University

Pressure fluctuations, which are inevitable in the operation of pumps, have a strong non-stationary characteristic and contain a great deal of important information representing the operation conditions. With an axial-flow pump as an example, a new method for time-frequency analysis based on the ensemble empirical mode decomposition （EEMD） method is proposed for research on the characteristics of pressure fluctuations. First, the pressure fluctuation signals are preprocessed with the empirical mode decomposition （EMD） method, and intrinsic mode functions （IMFs） are extracted. Second, the EEMD method is used to extract more precise decomposition results, and the number of iterations is determined according to the number of IMFs produced by the EMD method. Third, correlation coefficients between IMFs produced by the EMD and EEMD methods and the original signal are calculated, and the most sensitive IMFs are chosen to analyze the frequency spectrum. Finally, the operation conditions of the pump are identified with the frequency features. The results show that, compared with the EMD method, the EEMD method can improve the time-frequency resolution and extract main vibration components from pressure fluctuation signals.

关键词： pressure fluctuation ensemble empirical mode decomposition intrinsic modefunction correlation coefficient

A P2P streaming service architecture with distributed caching

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2007年第4期8卷 605-614页

作者： GUO pan-hong YANG Yang LI Xin-you Department of Computer Science and Technology University of Science and Technology Beijing Beijing 100083 China China State Information Center Beijing 100045 China

Multimedia streaming served through peer-to-peer (P2P) networks is booming nowadays. However, the end-to-end streaming quality is generally unstable due to the variability of the state of serve-peers. On the other hand, proxy caching is a bandwidth-efficient scheme for streaming over the Internet, whereas it is a substantially expensive method needing dedicated powerful proxy servers. In this paper, we present a P2P cooperative streaming architecture combined with the advantages of both P2P networks and multimedia proxy caching techniques to improve the streaming quality of participating clients. In this frame- work, a client will simultaneously retrieve contents from the server and other peers that have viewed and cached the same title before. In the meantime, the client will also selectively cache the aggregated video content so as to serve still future clients. The associate protocol to facilitate the multi-path streaming and a distributed utility-based partial caching scheme are detailedly dis- cussed. We demonstrate the effectiveness of this proposed architecture through extensive simulation experiments on large, Inter- net-like topologies.

关键词： Cooperative steaming Peer-to-peer networks Partial caching scheme Distributed caching

Planning of electric vehicle charging infrastructure under the Background of Big Data

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Journal of Control and Decision 2023年第3期10卷 374-381页

作者： Xiaodi Zhang Qiang Gao hong pan State Grid Zhejiang Electric Power Co. LtdHangzhouPeople’s Republic of China

Today, the problems of power consumption and environmental pollution caused by road trafficare very serious. Automobiles produce large amounts of carbon monoxide and nitrogen, dust,and particles, which are the primary user of the fuel. Unconventional design methods will preventthe international process of replacing fuel-filled vehicles with electric vehicles. The promotionand adoption of electric vehicles can effectively alleviate these problems, but the planning ofelectric vehicle charging facilities needs to be resolved as soon as possible. The state-of-the-artmodeand power model of public charging equipment proposed in this paper can solve the problemof positioning charging equipment in large-scale transmission networks and research onrelated charging materials and location planning and energy model design methods that arebeneficial to the future development.

关键词： Big Data technology electric vehicles charging facilities infrastructure planning charging equipment power consumption environmental pollution

On Direct Transformation Approach to Asymptotical Analytical Solutions of Perturbed Partial Differential Equation

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Communications in Theoretical Physics 2006年第4X期46卷 587-590页

作者： LIU hong-Zhun pan Zu-Liang LI Peng Department of Mathematics Zhejiang University Hangzhou 310027 China

In this article, we will derive an equality, where the Taylor series expansion around ε= 0 for any asymptotical analytical solution of the perturbed partial differential equation （PDE） with perturbing parameter e must be admitted. By making use of the equality, we may obtain a transformation, which directly map the analytical solutions of a given unperturbed PDE to the asymptotical analytical solutions of the corresponding perturbed one. The notion of Lie-Bgcklund symmetries is introduced in order to obtain more transformations. Hence, we can directly create more transformations in virtue of known Lie-Bgcklund symmetries and recursion operators of corresponding unperturbed equation. The perturbed Burgers equation and the perturbed Korteweg-de Vries （KdV） equation are used as examples.

关键词： perturbed partial differential equation asymptotical analytical solution Lie-Backlund symmetries

Onc*-Normal Subgroups in Finite Groups

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Acta Mathematica Sinica,English Series 2012年第3期28卷 623-630页

作者： Hua Quan WEI Wei Ping GU hong Fei pan School of Mathematics Science Guangxi Teachers Education University School of Mathematics and Computer Science Xinyang Normal University

A subgroup H of a finitegroup G is called a c＊-normal subgroup of G if there exists a

关键词： c*-Normal S-quasinormally embedded p-nilpotent p-supersolvable

Recursive Bayesian Algorithm for Identification of Systems with Non-uniformly Sampled Input Data

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International Journal of Automation and computing 2018年第3期15卷 335-344页

作者： Shao-Xue Jing Tian-hong pan Zheng-Ming Li School of Electrical Information and Engineering Jiangsu University Department of Electrical Engineering Huaian College of Information and Technology

To identify systems with non-uniformly sampled input data, a recursive Bayesian identification algorithm with covariance resetting is proposed. Using estimated noise transfer function as a dynamic filter, the system with colored noise is transformed into the system with white noise. In order to improve estimates, the estimated noise variance is employed as a weighting factor in the algorithm. Meanwhile, a modified covariance resetting method is also integrated in the proposed algorithm to increase the convergence rate. A numerical example and an industrial example validate the proposed algorithm.

关键词： Parameter estimation discrete time systems Gaussian noise Bayesian algorithm covariance resetting.

Influence of induced ciprofloxacin resistance on efflux pump activity of Klebsiella pneumoniae

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2013年第9期14卷 837-843页

作者： Hai-qin Zhong Shun ZHANG hong pan Ting CAI Department of Internal Medicine School of MedicineNingbo University Stem Cell Laboratory Ningbo No.2 Hospital Clinical Laboratory Ningbo No.2 Hospital Emergency Department Ningbo No.2 Hospital

Objective:The efflux pump(EP) is one of the major mechanisms of antibiotic resistance in Klebsiella ***,there are few reports on the effect of the abuse of antibiotic use on the activity of *** determine whether the use of low efficacy antibiotics has any effect on the activity of EPs and induces drug resistance in ***,we investigated the effect of ciprofloxacin on the activity of EPs in *** ***:Sixteen susceptible *** strains were isolated from patients and their minimum inhibitory concentrations(MICs) of ciprofloxacin were measured in the absence and presence of the pump inhibitor carbonyl cyanide m-chlorophenyl hydrazone(CCCP).The strains were then induced with a gradient of ciprofloxacin until the MICs of the strains showed no further increase,to obtain induced resistant *** EP activities of the strains before and after induction were compared using EP inhibition and ethidium bromide(EtBr) accumulation ***:The MIC values of the strains were 16 256 times higher after induction than before *** the presence of CCCP,the MIC values of 50% of the induced strains were 2 4-fold lower than that in the absence of this *** EtBr accumulation assay showed that the fluorescence of EtBr in the induced cells was lower than that in the cells before ***:EPs are widespread in susceptible and drug-resistant *** *** with ciprofloxacin may increase the activity of EPs in *** EtBr accumulation assay is more sensitive than the EP inhibition assay in evaluating the activity of EPs in ***.

关键词： Klebsiella pneumoniae Efflux pump Ciprofloxacin Antibiotic resistance

A new method for studying the 3D transient flow of misaligned journal bearings in flexible rotor-bearing systems

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2012年第4期13卷 293-310页

作者： Qiang LI Shu-lian LIU Xiao-hong pan Shui-ying ZHENG Institute of Chemical Machinery Zhejiang UniversityHangzhou 310027China Department of Electro-Mechanical Engneering Zhejiang University of Science and TechnologyHangzhou 310023China Institute of Modern Manufacture Engineering Zhejiang UniversityHangzhou 310027China

The effects of journal misalignment on the transient flow of a finite grooved journal bearing are presented in this study. A new 3D computational fluid dynamics (CFD) analysis method is applied. Also, the quasi-coupling calculation of transient fluid dynamics of oil film in journal bearing and rotor dynamics is considered in the analysis. Based on the structured mesh, a new approach for mesh movement is proposed to update the mesh volume when the journal moves during the fluid dynamics simula- tion of an oil film. Existing dynamic mesh models provided by FLUENT are not suitable for the transient oil flow in journal bearings. The movement of the journal is obtained by solving the moving equations of the rotor-bearing system with the calculated film pressure as the boundary condition of the load. The data exchange between fluid dynamics and rotor dynamics is realized by data files. Results obtained from the CFD model were consistent with previous experimental results on misaligned journal bearings. Film pressure, oil film force, friction torque, misalignment moment and attitude angle were calculated and compared for mis- aligned and aligned journal bearings. The results indicate that bearing performances are greatly affected by misalignment which is caused by unbalanced excitation, and the CFD method based on the fluid-structure interaction (FSI) technique can effectively predict the transient flow field of a misaligned journal bearing in a rotor-bearing system.

关键词： Misalignment Transient flow Computational fluid dynamics (CFD) Fluid-structure interaction (FSI) Journalbearing