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Effects of porous material on transient natural convection heat transfer of nano-fluids inside a triangular chamber

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Chinese Journal of Chemical Engineering 2020年第5期28卷 1203-1213页

作者： mohsen Izadi Mechanical Engineering Department Faculty of EngineeringLorestan UniversityKhorramabadIran

This study numerically investigates the impact of porous materials,nano-particle types,and their concentrations on transient natural convection heat transfer of nano-fluid inside a porous chamber with a triangular *** governing equations of the two-phase mixture model are separated on the computational domain and solved using the Finite Volume Method,taking into account the Darcy–Brinkman model for porous *** was observed that convection heat transfer inside the triangular chamber consists of three stages named initial,transient,and *** features of each step are provided in *** results suggested that the use of a hybrid nano-fluid(water/aluminum oxide-cooper)inside a porous glass material and an increase in volume fraction of nano-particles have adverse effects on heat transfer *** contrast,as the nano-particle volume fraction of the single nano-fluid(water/aluminum oxide)inside the chamber increased,convection heat transfer rate *** the same time,it was observed that the use of both nano-fluids(single and hybrid)in the porous environment of the aluminum foam could improve convection.

关键词： Transient natural convection Mixture model Darcy-Brinlanan model Rayleigh-Benard instability Triangular chamber

Orbital electronic heat capacity of hydrogenated monolayer and bilayer graphene

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Chinese Physics B 2017年第2期26卷 375-381页

作者： mohsen Yarmohammadi Young Researchers and Elite Club Kermanshah Branch Islamic Azad University Kermanshah Ira

The tight-binding Harrison model and Green＇s function approach have been utilized in order to investigate the contribution of hybridized orbitals in the electronic density of states（DOS） and electronic heat capacity（EHC） for four hydrogenated structures, including monolayer chair-like, table-like, bilayer AA- and finally AB-stacked graphene. After hydrogenation, monolayer graphene and bilayer graphene are behave as semiconducting systems owning a wide direct band gap and this means that all orbitals have several states around the Fermi level. The energy gap in DOS and Schottky anomaly in EHC curves of these structures are compared together illustrating the maximum and minimum band gaps are appear for monolayer chair-like and bilayer AA-stacked graphane, respectively. In spite of these, our findings show that the maximum and minimum values of Schottky anomaly appear for hydrogenated bilayer AA-stacked and monolayer table-like configurations, respectively.

关键词： hydrogenated monolayer and bilayer graphene Harrison model electronic heat capacity density of states Green's function

Adaptive Output Feedback Regulation for a Class of Uncertain Feedforward Time-Delay Nonlinear Systems

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Journal of Systems Science & Complexity 2020年第3期33卷 604-621页

作者： BELFEKI mohsen University of Sfax IPEISRoute Menzel ChakerKM 0.5B.P.1172Sfax 3018Tunisia Department of mathematics Alkurmah University collegeTaif UniversitySaudi Arabia

This paper addresses the global output feedback regulation problem for a class of uncertain feedforward time-delay nonlinear *** to the previous works,the nonlinear functions in the class of systems under consideration are dominated by an input-output function multiplied by an unknown parameter and linear unmeasured *** using only one dynamic gain and an appropriate Lyapunov-Krasovskii functionals,it is shown that the closed-loop system is globally asymptotically ***,a numerical example is provided to illustrate the effectiveness of the proposed design scheme.

关键词： Adaptive regulation dynamic gain output feedback uncertain feedforward time-delay systems

Erratum to:Soft multifunctional neurological electronic skin through intrinsically stretchable synaptic transistor

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Nano Research 2024年第9期17卷 8652-8652页

作者： Pengcheng Zhu Shuairong Mu Wenhao Huang Zeye Sun Yuyang Lin Ke Chen Zhifeng Pan mohsen Golbon Haghighi Roya Sedghi Junlei Wang Yanchao Mao Key Laboratory of Materials Physics of Ministry of Education School of Physics and MicroelectronicsZhengzhou UniversityZhengzhou 450001China School of Mechanical and Power Engineering Zhengzhou UniversityZhengzhou 450001China Department of Chemistry Shahid Beheshti UniversityTehran ***Iran

The original article has been corrected due to the incorrect PDF uploaded by the vendor's production.

关键词： stretch intrinsic electronic

Robust Hybrid Control for Ballistic Missile Longitudinal Autopilot

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Chinese Journal of Aeronautics 2011年第6期24卷 777-788页

作者： WAEL mohsen Ahmeda WAEL mohsen Ahmed QUAN Quan Department of Automatic Control School of Automation Science and Electrical Engineering Beihang University Beijing 100191 China State Key Laboratory of Virtual Reality Technology and Systems Beihang University Beijing 100191 China

This paper investigates the boost phase＇s longitudinal autopilot of a ballistic missile equipped with thrust vector control. The existing longitudinal autopilot employs time-invariant passive resistor-inductor-capacitor （RLC） network compensator as a control strategy, which does not take into account the time-varying missile dynamics. This may cause the closed-loop system instability in the presence of large disturbance and dynamics uncertainty. Therefore, the existing controller should be redesigned to achieve more stable vehicle response. In this paper, based on gain-scheduling adaptive control strategy, two different types of optimal controllers are proposed. The first controller is gain-scheduled optimal tuning-proportional-integral-derivative （PID） with actuator constraints, which supplies better response but requires a priori knowledge of the system dynamics. Moreover, the controller has oscillatory response in the presence of dynamic uncertainty. Taking this into account, gain-scheduled optimal linear quadratic （LQ） in conjunction with optimal tuning-compensator offers the greatest scope for controller improvement in the presence of dynamic uncertainty and large disturbance. The latter controller is tested through various scenarios for the validated nonlinear dynamic flight model of the real ballistic missile system with autopilot exposed to external disturbances.

关键词： ballistic missiles attitude control gain-scheduling optimal tuning-control LQ optimal regulators

Assessment of mobile and potential mobile trace elements extractability in calcareous soils using different extracting agents

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Frontiers of Environmental Science & Engineering 2020年第1期14卷 109-125页

作者： mohsen Jalali Ziba Hurseresht Department of Soil Science College of AgricultureBu_Ali Sina UniversityHamedanIran

Understanding trace elements mobility in soils,extracting agents,and their relationships with soil components,are essential for predicting their movement in soil profile and availability to plants.A laboratory study was conducted to evaluate extractability of cadmium(Cd),cobalt(Co),copper(Cu),nickel(Ni),and zinc(Zn)from calcareous soils utilizing various extracting agents to be specific CaCU,DTPA,EDTA,HNO3,MgCl2,NaN03,NH4NO3,and *** analysis indicated that DTPA and NH4OAc,HN03 and EDTA,and M gCl2 and NH4NO3 extracting agents yielded comparative values,whereas NaN03 and CaCl2 have shown different behavior than other extracting agents for all studied trace *** speciationof extracted trace elements in solutions indicated that in the CaCl2,NaN03,NH4NO3,and MgCl2 extracting agents most extracted Cd,Co,Ni,Zn,and part f Cu were as free ions and may be re-adsorbed on soils,leading to lower extractability,whereas,in the caseof HNO3 extracting agent,the likelihoodof re-adsorptionof trace elements may be *** resultsof speciationof trace elements using NH4OAc DTPA,and EDTA extracting agents showed that Me-(Acetate)3,Me-(Acetate)2(aq),Me(DTPA)3-3-,Me(EDTA)2-.and MeH(EDTA)-complexes dominated in solutions indicating that the extracted trace elements may not be re-adsorbed on soils,leading to higher *** resultsof this study are useful for short and long-term evaluationsof trace elements mobility and further environmental impacts.

关键词： Mobility Calcareous soils Extracting agents Trace elements

Overview of grid-connected two-stage transformer-less inverter design

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Journal of Modern Power Systems and Clean Energy 2018年第4期6卷 642-655页

作者： mohsen SHAYESTEGAN Department of Electric Electronic and system EngineeringFaculty of Engineering and Built Environment Universiti Kebangsaan Malaysia

This paper gives an overview of previous studies on photovoltaic(PV) devices, grid-connected PV inverters,control systems, maximum power point tracking(MPPT)control strategies, switching devices and transformer-less inverters. The literature is classified based on types of PV systems, DC/DC boost converters and DC/AC inverters,and types of controllers that control the circuit to ensure maximum power tracking and stabilization of load and input voltage. This is followed by the theoretical background of PV devices, an overview of MPPT controllers and common mode leakage current, and a detailed investigation of different inverter topologies regarding the ground leakage current. Furthermore, design principles of power converters, such as DC/DC boost converters, and single-phase inverters are discussed. The paper also discusses limitations and benefits in addition to the basic operating principles of several topologies. Finally, the proposed system is derived and its simulation results are discussed to offer the next generation of grid connected PV systems.

关键词： Transformer-less inverter DC/DC boost converter Maximum power point tracking(MPPT) controller Grid connected photovoltaic(PV) system

Introducing an effective coherence function to generate non-uniform ground motion on topographic site using time-domain boundary element method

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Earthquake Engineering and Engineering Vibration 2021年第1期20卷 89-100页

作者： mohsen Isari Reza Tarinejad Faculty of Civil Engineering University of TabrizTabrizEast Azerbaijan ProvinceIran

In this study,a comprehensive parametric analysis was performed on non-uniform excitation of V-shaped topography using the boundary element method in time *** this purpose,wave scattering analysis was carried out on a topography subjected to the SV-wave for different predominant frequencies and shape *** on the numerical results,new coherence and time delay functions are proposed to generate non-uniform ground motion for topographic *** efficiency and accuracy of the proposed functions for real engineering problems are indicated by comparison with observations reported in previous literature.

关键词： site effect time delay boundary element method amplification coherence function

Robust Controller Synthesis and Analysis in Inverter-Dominant Droop-Controlled Islanded Microgrids

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IEEE/CAA Journal of Automatica Sinica 2021年第8期8卷 1401-1415页

作者： S.mohsen Azizi School of Applied Engineering and Technology and the Department of Electrical and Computer EngineeringNew Jersey Institute of TechnologyNJ 07102 USA

This work investigates the problem of controller design for the inverters in an islanded ***-synthesis controllers and local droop controllers are designed to regulate the output voltages of inverters and share power among them,*** designed controllers alleviate the need for additional sensors to measure the states of the system by relying only on output *** is shown that the designed-synthesis controller properly damps resonant oscillations,and its performance is robust to the control-loop time delay and parameter *** stability of a droop-controlled islanded microgrid including multiple distributed generation(DG)units is analyzed by linearizing the nonlinear power flow model around the nominal operating point and applying theorems from linear *** is indicated that the droop controller stabilizes the microgrid system with dominantly inductive tie-line impedances for all values of resistive-inductive loads,while for the case of resistive-capacitive loads the stability is conditioned on an upper bound on the load *** robust performance of the designed-synthesis controller is studied analytically,compared with the similar analysis in an control(benchmark)framework,and verified by simulations for a four DG benchmark ***,the robustness of the droop controllers is analyzed by Monte Carlo simulations in the presence of local voltage fluctuations and phase differences among neighboring DGs.

关键词： Droop control inverter microgrid Monte Carlo simulation robust control μ-synthesis