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International Journal of Automation and computing 2011年第4期8卷 381-390页

作者： hamid reza karimi Department of Engineering Faculty of Engineering and Science University of Agder N-4898 Grimstad Norway

This paper proposes an adaptive synchronization problem for the master and slave structure of linear systems with nonlinear perturbations and mixed time-varying delays comprising different discrete and distributed time delays. Using an appropriate Lyapunov-Krasovskii functional, some delay-dependent sufficient conditions and an adaptation law including the master-slave parame- ters are established for designing a delayed synchronization law in terms of linear matrix inequalities（LMIs）. The time-varying controller guarantees the H ∞ synchronization of the two coupled master and slave systems regardless of their initial states. Particularly, it is shown that the synchronization speed can be controlled by adjusting the updated gain of the synchronization signal. Two numerical examples are given to demonstrate the effectiveness of the method.

关键词： Adaptive synchronization master-slave systems delay H ∞ performance nonlinear perturbations.

Global Mittag-Leffler stability for fractional-order coupled systems on network without strong connectedness

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Science China(Information Sciences) 2020年第3期63卷 184-194页

作者： Xin MENG Yonggui KAO hamid reza karimi Cunchen GAO School of Mathematical Sciences Ocean University of China Department of Mechanical Engineering Politecnico di Milano Department of Mathematics Harbin Institute of Technology (Weihai)

This study investigates the global Mittag-Leffler stability(MLS) problem of the equilibrium point for a new fractional-order coupled system(FOCS) on a network without strong connectedness. In particular, an integer-order coupled system is extended into the FOCS on a complex network without strong connectedness. Based on the theory of asymptotically autonomous systems and graph theory, sufficient conditions are derived to ensure the existence, uniqueness, and global MLS of the solutions of this FOCS on a network. Finally, a numerical example is provided to demonstrate the validity and potential of the proposed method for studying the MLS of FOCSs.

关键词： global Mittag-Leffler stability fractional-order coupled system connectedness

Organo-silane compounds in medium density fiberboard:physical and mechanical properties

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Journal of Forestry Research 2015年第2期26卷 495-500页

作者： hamid reza Taghiyari Ali karimi Paridah Md.Tahir Wood Science & Technology Department Faculty of Civil EngineeringShahid Rajaee Teacher Training University Department of Wood and Paper Science & Technology Faculty of Natural ResourcesThe University of Tehran Laboratory of Biocomposite Technology Institute of Tropical Forestry & Forest Products (INTROP)University Putra Malaysia (UPM)

We studied the effects of nanoparticles of organo-silane（NOS） compounds in the size range of20–80 nm on physical and mechanical properties in medium density fiberboard,and used NOS at four consumption levels of 0,50,100,and 150 g kg-1dry wood *** of all treatments was kept constant at 0.67 g *** water-repellent property of organo-silane significantly reduced water absorption（WA） and thickness swelling but mechanical properties declined due to the reduced proportion of wood-fiber as organo-silane was added to the matrix：the compression ratio of MDF panels and the integrity among wood-fibers both declined,resulting in reduced mechanical *** recommend use of 50 g of NOS/kg wood-fiber to improve WA and thickness swelling while retaining acceptable mechanical properties.

关键词： Composite-board Medium-density fiberboard(MDF) Nanotechnology Physical and mechanical properties Water-repellant Organo-silane

Wettability alteration and retention of mixed polymer-grafted silica nanoparticles onto oil-wet porous medium

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Petroleum Science 2021年第3期18卷 962-982页

作者： hamid Daneshmand Masoud rezaeinasab Masoud Asgary Meysam karimi Department of Physics University of TehranTehranIran Department of Chemistry Faculty of ScienceYazd UniversityYazdIran Department of Materials Engineering Tarbiat Modares UniversityTehranIran Department of Material Science Shahreza BranchIslamic Azad UniversityIsfahanIran

Enhanced oil recovery(EOR)processes are applied to recover trapped or residual oil in the reservoir rocks after primary and secondary recovery *** the wettability of the rock from oil-wet to water-wet is named wettability *** is an important factor for *** to their unique properties,nanoparticles have gained great attention for improving oil *** the promising results,the main challenges of applying nanoparticles are related to the colloidal stability of the nanofuids in the harsh conditions of the *** recent years,polymer-grafted nanoparticles have been considered as novel promising materials for *** obtained results showed that adding a hydrophobic agent trimethoxy(propyl)silane on the surface of modifed silica nanoparticles with polyethylene glycol methyl ether has an efective role in improving retention and wettability alteration,especially in the oil-wet substrate due to hydrophobic *** modifed silica nanoparticle by mixed polyethylene glycol methyl ether(Mn~5000)and trimethoxy(propyl)silane showed a proper performance at a concentration of 1000 ppm and a salinity range of 2000-40,000 *** obtained fndings can help for a better understanding of the silica nanofuid modifcation with both hydrophilic and hydrophobic agents for the EOR application of near-wellbore.

关键词： Wettability alteration Retention Silica nanoparticle Surface modifcation Enhanced oil recovery

Electrocatalytic performance of Pt/Ru/Sn/W fullerene electrode for methanol oxidation in direct methanol fuel cell

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燃料化学学报 2013年第1期41卷 91-95页

作者： Mohammad karimi Forouzan Aboufazeli hamid reza Lotfi Zadeh Zhad Omid Sadeghi Ezzatollah Najafi Department of Chemistry Shahr-e-Rey BranchIslamic Azad University

In this work,fullerene was modified by platinum,ruthenium,tin and tungsten *** material was characterized by XRD,ICP-OES and TEM *** average nanoparticle size on fullerene was 5-8 *** application of this material was investigated as a catalyst for methanol oxidation in direct methanol fuel cell.A glassy carbon electrode was modified by Pt/Ru/Sn/W fullerene and electrocatalytic activity of the electrode toward methanol oxidation in basic medium has been demonstrated and investigated using cyclic *** catalyst showed good reactivity for methanol oxidation.

关键词：摘要编辑部编辑工作读者

Semiactive Vibration Control of a Bridge Structure with Unknown Coupling Dynamics of the Crossing Vehicles

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Semiactive Vibration Control of a Bridge Structure with Unkn...

LQG Control Design for Balancing an Inverted Pendulum Mobile Robot

第二十九届中国控制会议

作者： Mauricio ZAPATEIRO hamid reza karimi Department of Applied Mathematics Ⅲ Technical University of Catalonia Department of Engineering Faculty of Engineering and ScienceUniversity of Agder

This work deals with the problem of vibration attenuation for a bridge structure subjected to a specific kind of uncertain excitation due to a temporary coupling of the bridge structure with an unknown dynamical system which is represented by a crossing *** vibration control strategy is applied by using magnetorhelogical（MR） dampers.A robust controller is designed using only the measurable state vector of the bridge *** effectiveness of the proposed control scheme is verified by the numerical simulation.

关键词： Vibration Control Semiactive Control Uncertainties Unknown Coupling Flexible Structures.

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Intelligent Control and Automation 2011年第2期2卷 160-166页

作者： Ragnar Eide Per Magne Egelid Alexander Stamso hamid reza karimi Department of Engineering Faculty of Engineering and ScienceUniversity of AgderGrimstadNorway

The objective of this paper is to design linear quadratic controllers for a system with an inverted pendulum on a mobile robot. To this goal, it has to be determined which control strategy delivers better performance with respect to pendulum’s angle and the robot’s position. The inverted pendulum represents a challenging control problem, since it continually moves toward an uncontrolled state. Simulation study has been done in MATLAB Simulink environment shows that both LQR and LQG are capable to control this system successfully. The result shows, however, that LQR produced better response compared to a LQG strategy.

关键词： LQG Control Inverted Pendulum Mobile Robot

Positive l1 observer design for positive switched systems with time-varying delays via delta operator approach

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Positive l1 observer design for positive switched systems wi...

脆性材料I型(张开)-断裂韧性测定的PFC2D和试验研究:一种新方法

第26届中国控制与决策会议

作者： Shuo Li Zhengrong Xiang hamid reza karimi School of Automation Nanjing University of Science and Technology Department of Engineering Faculty of Engineering and ScienceUniversity of Agder

This paper investigates the problem of 1l observer design for positive switched systems with time-varying delays via delta operator approach. The purpose is to design a positive observer such that the estimated error exponentially converges to zero and the 1l-gain from the disturbance input to the estimated error is less than a prescribed level. Based on the average dwell time approach, a sufficient condition for the existence of a positive 1l observer for the considered system is established by constructing an appropriate co-positive type Lyapunov-Krasovskii functional in delta domain. Finally, a numerical example is presented to explicitly demonstrate the effectiveness and feasibility of the proposed method.

关键词： Positive 1l observer Positive switched systems Delta operator Exponential stability Average dwell time

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Acta Mechanica Sinica 2024年第2期40卷 116-130页

作者：付金伟 Hadi Haeri Joseph FLabuz Vahab Sarfarazi Pouyan Ebneabbasi MRM Aliha hamid reza karimi Shirin Jahanmiri Mohammad Fatehi Marji School of Civil Engineering and Transportation North China University of Water Resources and Electric PowerZhengzhou450046China Department of Mining Engineering Higher Education Complex of ZarandShahid Bahonar University of KermanKermanIran Department of Civil Environmentaland Geo-EngineeringUniversity of MinnesotaMinneapolis55455USA Department of Mining Engineering Hamedan University of TechnologyHamedanIran Research Scholar Civil Engineering DepartmentIslamic Azad UniversityHamedanIran Welding and Joining Research Center School of Industrial EngineeringIran University of Science and TechnologyNarmakTehranIran School of Civil Engineering Iran University of Science and Technology(IUST)NarmakTehranIran Department of Mine Exploitation Engineering Faculty of Mining and MetallurgyInstitute of EngineeringYazd UniversityYazdIran

在本文研究中,通过利用优势边缘缺口盘型(END)试样,确定了石灰石的断裂韧性,提出了一种新的石灰石归一化相应力、高相变的计算方法.采用柔性有限元法(FEM)对试样的I型(张开)-断裂韧性进行了精确计算,并得到了相应实用公式.在试验中,还... 详细信息

在本文研究中,通过利用优势边缘缺口盘型(END)试样,确定了石灰石的断裂韧性,提出了一种新的石灰石归一化相应力、高相变的计算方法.采用柔性有限元法(FEM)对试样的I型(张开)-断裂韧性进行了精确计算,并得到了相应实用公式.在试验中,还使用含缺口巴西圆盘(NBD)试件,测试了END程序的准确性.为了在数值上重现这些测试并验证断裂韧性测量的正确性,还对END测试进行了离散元分析.数值模拟结果与实验结果吻合良好.然而,END研究所确定的韧性水平低于NBD测试规定的韧性水平,这是因为END石灰石样品中的缺口具有均匀的拉伸应力分布.

关键词：断裂韧性脆性材料实用公式拉伸应力巴西圆盘离散元分析相变归一化