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永磁伺服系统自适应加权无模型预测电流控制

电力电子技术 2024年第1期58卷 23-26,56页

作者：闵琦张懿陈冠廷江苏科技大学自动化学院江苏镇江212000

永磁伺服系统采用的隐极式永磁同步电机(PMSM)存在参数未知或失配时电流控制性能下降和开关损耗增大的问题,因此提出加权型成本函数驱动的无模型预测电流控制(MFCC)策略。首先,针对电气参数未知或失配的问题,采用以电流误差变化速率为... 详细信息

永磁伺服系统采用的隐极式永磁同步电机(PMSM)存在参数未知或失配时电流控制性能下降和开关损耗增大的问题,因此提出加权型成本函数驱动的无模型预测电流控制(MFCC)策略。首先,针对电气参数未知或失配的问题,采用以电流误差变化速率为输入量的最小二乘法对电机参数分组辨识。然后应用比例积分微分(PID)控制原理设计权重系数调节器,完成对成本函数中电流成本和开关成本自调节。最终,实验结果表明该方法能减少电流成本,提高电流控制性能和系统鲁棒性,能减少开关成本,使开关频率和开关损耗下降。

关键词：永磁同步电机成本函数开关频率

Synthesis and characterization of biodegradable aliphatic polyesters using dibutylmagnesium as initiator

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Chinese Chemical Letters 2007年第6期18卷 744-746页

作者： Lian Liu Zhi Yong Wei min qi Electromechanics and Materials Engineering College Dalian Maritime University Dalian 116026 China School of Materials Science and Engineering Dalian University of Technology Dalian 116024 China

Aliphatic polyesters were synthesized via the ring opening polymerization of the corresponding lactones initiated with dibutylmagnesium both in bulk and in solution. The resulting polymers were characterized by 1H, 13C NMR, GPC and XRD. The results indicated that dibutylmagnesium is an effective initiator for the ring opening polymerization of lactones.

关键词： Aliphatic polyesters Lactones Dibutylmagnesium Biodegradable Biomaterials

Study on Stress-softening Effect in CuZnAl Shape Memory Alloys

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Rare Metals 1989年第4期9卷 38-43页

作者： Yi, Huchun qi, min Wang, Fengting Yang, Dazhi Dalian Univ of Technology China

The effect of mechanical cyclings on the stress-strain(S-S) curves was studied systematically using tensile tests over a wide temperature range. Two-stage yielding was observed in the temperature range between Ms and the ultimate temperature to induce martensite, denoted by Md. The first stage was confirmed to be associated with stress-induced martensite(SIM) and the second stage was associated with the yielding of SIM. When the samples were mechanically cycled between Ms and Md, a stress-softening phenomenon was observed. The cyclings made the martensite amount increase, critical stress σc of SIM decrease according to exponential law, and the entropy(also enthalpy) of the parent to martensite transformation also decrease. The variations of SIM relative amount were determined by recording the changes of electrical resistances in the course of tension.

关键词： Copper and Alloys Phase Transitions Copper Metallography Martensite Materials with Memory Phase Transitions Metals Testing Tensile Tests Stresses Effects

Mean-square Stability of Stochastic Age-dependent Delay Population Systems with Jumps

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Acta Mathematicae Applicatae Sinica 2018年第1期34卷 145-154页

作者： qiang LI qi-min ZHANG Bo-qiang CAO School of Mathematics and Statistics Ningxia University Yinchuan 750021 China School of Mathematics and Information Sciences Beifang University of Nationalities Yinchuan 750021 China

In this paper, we present the compensated stochastic θ method for stochastic age-dependent delay population systems（SADDPSs） with Poisson jumps. The definition of mean-square stability of the numerical solution is given and a sufficient condition for mean-square stability of the numerical solution is derived. It is shown that the compensated stochastic θ method inherits stability property of the numerical solutions. Finally,the theoretical results are also confirmed by a numerical experiment.

关键词： stochastic age-dependent delay population systems compensated stochastic θ method poisson jumps mean-square stability

Formation of nanocrystalline microstructure in arc ion plated CrN films

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 73-77页

作者： qi-min WANG Se-Hun KWON Kwang-Ho KIM National Core Research Center for Hybrid Materials Solution Pusan National University Busan 609-735 Korea School of Materials Science and Engineering Pusan National University Busan 609-735 Korea

Applying negative bias voltages caused significant microstructure changes in arc ion plated CrN films. Nanocrystalline microstructures were obtained by adjusting the negative bias voltage. Structural characterizations of the films were carried out using X-ray diffractometry (XRD) and high-resolution transmission electron microscopy (HR-TEM). The results indicated that increasing ion bombardment by applying negative bias voltages resulted in the formation of defects in the CrN films, inducing microstructure evolution from micro-columnar to nanocrystalline. The microhardness and residual stresses of the films were also affected. Based on the experimental results, the evolution mechanisms of the film microstructure and properties were discussed by considering ion bombardment effects.

关键词： CrN thin films deposition microstructure arc ion plating ion bombardment

A linear complementarity model for multibody systems with frictional unilateral and bilateral constraints

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Acta Mechanica Sinica 2011年第4期27卷 587-592页

作者： Hai-Ping Gao qi Wang Shi-min Wang Li Fu Department of dynamics and control Beihang University 100191 Beijing China

The Lagrange-I equations and measure differential equations for multibody systems with unilateral and bilateral constraints are constructed. For bilateral constraints, frictional forces and their impulses contain the products of the filled-in relay function induced by Coulomb friction and the absolute values of normal constraint reactions. With the time-stepping impulse-velocity scheme, the measure differential equations are discretized. The equations of horizontal linear complementarity problems （HLCPs）, which are used to compute the impulses, are constructed by decomposing the absolute function and the filled-in relay function. These HLCP equations degenerate into equations of LCPs for frictional unilateral constraints, or HLCPs for frictional bilateral constraints. Finally, a numerical simulation for multibody systems with both unilateral and bilateral constraints is presented.

关键词： Coulomb friction Bilateral constraint Unilat-eral constraint - Horizontal linear complementarity problem(HLCP) Time-stepping impulse-velocity algorithm

Toll-like receptor 2-mediated NF-kappa B pathway activation in ocular surface epithelial cells

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Eye and Vision 2017年第1期4卷 93-99页

作者： Aihua Hou min qi Tin Louis Tong Ocular Surface Research Group Singapore Eye Research InstituteSingaporeSingapore Duke-NUS Graduate Medical School SingaporeSingapore Singapore National Eye Center SingaporeSingapore Yong Loo Lin School of Medicine National University of SingaporeSingaporeSingapore

Background:Gram-positive bacteria stimulate Toll-like receptor(TLR)2 and then activate the pro-inflammatory nuclear factor-kappa B(NF-κB)*** the human ocular surface is heavily colonised by gram-positive cocci bacteria,a balance of activation/repression of NF-κB target genes is essential to avoid uncontrolled infection or autoimmune-related *** is advantageous to test NF-κB targeting molecules in an ocular surface culture system that allows assessment of temporal NF-κB activation in a longitudinal fashion without destruction of *** initial testing under standardised conditions should reduce the number of molecules that progress to further evaluation in animal *** study aims to establish an in-vitro cell culture system to assess NF-κB activation in the context of ocular surface ***:NF-κB activity was evaluated through a secretory alkaline phosphatase reporter assay(SEAP).Immunoblots and immunofluorescence were used to examine IκBαphosphorylation and p65/p50 nuclear *** chemoattractant protein-1(MCP-1)transcripts were evaluated by real time PCR and protein levels were measured by ***:NF-κB activity in HCE-T cells treated with TLR2 activator Pam3CSK4 was higher than control cells at both 6 and 24 ***3CSK4-stimulated NF-κB activation was inhibited by IκK inhibitors,Wedelolactone and *** Pam3CSK4 treated cells,active NF-κB subunits p50 and p65 increased in cell nuclear fractions as early as 1.5 *** the level of total IκB-αremained constant,phospho-IκB-αincreased with treatment over *** the culture media of Pam3CSK4-stimulated cells,MCP-1 protein level was increased,which was suppressed in the presence of IκK ***:NF-κB pathway can be activated by the TLR2 ligand and inhibited by IκK inhibitors in the ocular surface cell culture *** cell culture system may be used to evaluate TLR-related innate defences in ocular surface diseases.

关键词： TLR2 NF-κB pathway Activation Ocular surface cells

Detection of dopamine at graphene-ZIF-8 nanocomposite modified electrode

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Chinese Chemical Letters 2017年第7期28卷 1473-1478页

作者： Yan-Yan Zheng Chang-Xia Li Xiao-Teng Ding qi Yang Ya-min qi Hui-min Zhang Liang-Ti Qu School of Chemistry and Chemical Engineering Beijing Institute of TechnologyBeijing 100081China

A hybrid graphene-ZIF-8（G-ZIF-8） nanocomposite modified electrode was prepared in our work. SEM characterization shows that nanocrystals of zeolitic imidazolate frameworks（ZIF-8） were homogeneously well-intergrown on the surface of graphene and thus the graphene sheets were refrained from restacking, which implies the high accessible surface area. The BET results further testifies that G-ZIF-8composites had a larger surface area than 3D graphene. G-ZIF-8 modified electrode exhibited excellent electroanalytical performance for dopamine. The linear concentration range was from 3.0 mmol/L to1.0 mmol/L with the detection sensitivity of 0.34 m A/mmol/L and the detection limit of 1.0 mmol/L was obtained. The interference study, electrode stability and reproducibility were carried out. In addition, the prepared sensor was applied to the detection of DA in serum sample with recoveries from 96.8% to100.7%. It is believable that the structure characteristic of G-ZIF-8 nanocomposite is favorable for using MOFs to fabricate highly sensitive electrochemical sensor

关键词： ZIF-8 Graphene Nanocomposite Modified electrode Dopamine

Electronic Structure and Optical Properties of K2Ti6O13 Doped with Transition Metal Fe or Ag

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Chinese Journal of Chemical Physics 2018年第3期31卷 318-324,368页

作者： Heng-li Chen Hong-yan Lu Yu-min qi Peng Jin School of Material Science and Engineering Hebei University of TechnologyTianjin 300130China School of Physics and Electronic Information Huaibei Normal UniversityHuaibei 235000China

Based on the experimental study of the optical properties of K2Ti6O13 doped with Fe or Ag,their electronic structures and optical properties are studied by the first-principles method based on the density functional theory（DFT）. The calculated optical properties are consistent with the experiment results. K2Ti6O13 doped with substitutional Fe or Ag has isolated impurity bands mainly stemming from the hybridization by the Fe 3d states or Ag 4d states with Ti 3d states and O 2p states and the band gap becomes narrower, the absorption edge of K2Ti6O13 thus has a clear red shift and the absorption of visible light can be realized after doping. For Fe-doped K2Ti6O13, the impurity bands are in the middle of the band gap, suggesting that they can be used as a bridge for valence band electrons transition to the conduction band. For Ag-doped K2Ti6O13,the impurity bands form a shallow acceptor above the valence band and can reduce the recombination rate of photoexcited *** experimental and calculated results are significant for the development of K2Ti6O13materials that have absorption under visible light.

关键词： First-principles Doping Electronic structures Optical properties