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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

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

Correlation between structural phase transition and physical properties of Co^(2+)/Gd^(3+)co-substituted copper ferrite

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Journal of Rare Earths 2024年第7期42卷 1344-1353,I0006页

作者： mohsen Choupani Ahmad Gholizadeh School of Physics Damghan UniversityDamghan36716-45667Iran

The doping of the spinel ferrites with selective cations usually improves the properties of the parent *** effect of Co^(2+)/Gd^(3+)co-substitution on the microstructure,optical,and magnetic properties of Cu1-xCoxFe2-xGdxO4 prepared by the citrate-nitrate auto-combustion synthesis was *** of the samples was performed with powder X-ray diffraction(XRD),Raman and Fouriertransform infrared(FTIR)spectroscopy,field-emission scanning electron microscopy,X-ray energydispersive spectroscopy,UV-Vis spectroscopy,and a vibrating sample *** results of XRD,Raman,and FTIR analysis show a gradual structural phase transition from a tetragonal(I41/amd)structure to a cubic(Fd3m)*** bandgap energy of the studied samples is in a range of 1.57-1.75 eV with a minimum in sample x=0.06 and then *** investigations show that the presence of Co^(2+)/Gd^(3+)cations in an octahedral site of the copper ferrite structure could increase saturation magnetization and coercive field from 567.9 Oe and 23.62 emu/g to 929.4 Oe and 28.27 emu/g,respectively.

关键词： Spinel copper ferrite Citrate-nitrate method Structure phase transition Microstructure properties Magnetic properties Rare earths

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

A dynamical approach to the exterior geometry of a perfect fluid as a relativistic star

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Chinese Physics C 2013年第2期37卷 26-38页

作者： mohsen Fathi Department of Physics Islamic Azad University Central Tehran Branch Tehran Iran

In this article, we assume that a cold charged perfect fluid is constructing a spherical relativistic star. Our purpose is the investigation of the dynamical properties of its exterior geometry, through simulating the... 详细信息

关键词： astrophysics relativistic stars geodesics

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

Hydrodynamic and heat transfer properties of magnetic fluid in porous medium considering nanoparticle shapes and magnetic field-dependent viscosity

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Chinese Journal of Chemical Engineering 2020年第2期28卷 329-339页

作者： mohsen Izadi Masoud Javanahram Seyed mohsen Hashem Zadeh Dengwei Jing Mechanical Engineering Department Lorestan UniversityKhorramabadIran Mechanical Engineering Department Islamic Azad UniversityBushehrIran Department of Mechanical Engineering Shahid Chamran University of AhvazIran School of Energy and Power Engineering State Key Lab of Multiphase Flow in Power EngineeringXi'an Jiaotong UniversityXi'an 710049China

The purpose of this paper is to study the characteristics of the combined convection heat transfer and a micropolar nanofluid flow passing through an impermeable stretching sheet in a porous *** nanofluid flow field is affected by a magnetic field perpendicular to the *** dynamic viscosity of the micropolar nanofluid changes under the influence of the magnetic *** continuity,linear momentum,angular momentum,and energy equations are first simplified using the order of magnitude technique that,along with the applied boundary conditions and the definition of the appropriate parameters,are transferred to the similarity space using the similarity *** the resulting equations are solved using the Runge–Kutta *** distinction of the macroscale and microscale flow fields and temperature fields resulting from different nanoparticle shapes was *** the Hartmann number,the vortex viscosity parameter,the magnetic parameter,the nanoparticle volume fraction,and the permeability parameter of the porous media increased the surface friction on the *** the vortex viscosity parameter,the magnetic parameter,and the volume fraction of the nanoparticles increases the Nusselt number.

关键词： MHD-combined convection Porous media Magnetic micropolar nanofluid

Development of Voice Control Algorithm for Robotic Wheelchair Using MIN and LSTM Models

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Computers, Materials & Continua 2022年第11期73卷 2441-2456页

作者： mohsen Bakouri Department of Medical Equipment Technology College of Applied Medical ScienceMajmaah UniversityMajmaah City11952Saudi Arabia Department of Physics College of ArtsFezzan UniversityTraghen71340Libya

In this work,we developed and implemented a voice control algorithm to steer smart robotic wheelchairs(SRW)using the neural network *** technique used a network in network(NIN)and long shortterm memory(LSTM)structure integrated with a built-in voice recognition *** Android Smartphone application was designed and configured with the proposed method.A Wi-Fi hotspot was used to connect the software and hardware components of the system in an offline *** operate and guide SRW,the design technique proposed employing five voice commands(yes,no,left,right,no,and stop)via the Raspberry Pi and DC *** native Arabic speakers trained and validated an English speech corpus to determine the method’s overall *** design method of SRW was evaluated in both indoor and outdoor environments in order to determine its time response and *** results showed that the accuracy rate for the system reached 98.2%for the five-voice commends in classifying voices *** interesting finding from the real-time test was that the root-mean-square deviation(RMSD)for indoor/outdoor maneuvering nodes was 2.2∗10–5(for latitude),while that for longitude coordinates was a whopping 2.4∗10–5(for latitude).

关键词： Network in network long short-term memory voice recognition wheelchair

Organosoluble Aliphatic-Aromatic Poly(ether-amide)s Based on Pyridine Moiety in the Main Chain: Synthesis, Characterization and Thermal Studies

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Chinese Journal of Polymer Science 2014年第6期32卷 758-767页

作者： mohsen Hajibeygi Meisam Shabanian Young Researchers Club Varamin Pishva Branch Islamic Azad University Department of Chemistry Farahan Branch Islamic Azad University

A series organosoluble and heterocyclic poly（ether-amide）s （PEA）s were synthesized from a new diamine containing pyridine moiety and four aliphatic-aromatic dicarboxylic acids by direct polycondensation reactions. Dicarboxilic acids 4a-4d containing ether groups were synthesized in two step reactions. At first, dialdehydes 3a-3d were synthesized from four dibromo alkanes la-ld and 4-hydroxybenzaldehyde 2, then dicarboxilic acids 4a-4d were synthesized from dialdehydes 3a-3d and malonic acid in a solvent free reaction. On the other hand, the new diamine 8 containing pyridine ring was synthesized in two step reactions. The structures of synthesized monomers and polymers were proven by FTIR, NMR spectroscopy and elemental analysis. Also all of the above polymers were fully characterized by inherent viscosity, solubility tests, gel permeation chromatography （GPC）, differential scanning calorimetry （DSC） and thermogravimetric analysis （TGA）. The resulted PEAs have shown good inherent viscosities, solubility and thermal properties.

关键词： Poly(ether-amide) Organosoluble Aliphatic-aromatic Polycondensation Malonic acid.