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InGaN micro-light-emitting diodes monolithically grown on Si:achieving ultra-stable operation through polarization and strain engineering

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Light(Science & Applications) 2022年第10期11卷 2540-2548页

作者： Yuanpeng Wu Yixin Xiao ishtiaque navid Kai Sun Yakshita Malhotra Ping Wang Ding Wang Yuanxiang Xu Ayush Pandey Maddaka Reddeppa Walter Shin Jiangnan Liu Jungwook Min Zetian Mi Department of Electrical Engineering and Computer Science University of MichiganAnn ArborMI 48109USA Department of Materials Science and Engineering University of MichiganAnn ArborMI 48109USA

Micro or submicron scale light-emitting diodes(μLEDs)have been extensively studied recently as the next-generation display *** is desired that μLEDs exhibit high stability and efficiency,submicron pixel size,and potential monolithic integration with Si-based complementary metal-oxide-semiconductor(CMOS)*** such uLEDs,however,has remained a daunting *** polar nature of Ill-nitrides causes severe wavelength/color instability with varying carrier concentrations in the active *** etching-induced surface damages and poor material quality of high indium composition InGaN quantum wells(QWs)severely deteriorate the performance of uLEDs,particularly those emitting in the green/red *** we report,for the first time,μLEDs grown directly on Si with submicron lateral *** μLEDs feature ultra-stable,bright green emission with negligible quantum-confined Stark effect(QCSE).Detailed elemental mapping and numerical calculations show that the QCSE is screened by introducing polarization doping in the active region,which consists of InGaN/AlGaN QWs surrounded by an AlGaN/GaN shell with a negative Al composition gradient along the *** comparison with conventional GaN barriers,AlGaN barriers are shown to effectively compensate for the tensile strain within the active region,which significantly reduces the strain distribution and results in enhanced indium incorporation without compromising the material *** study provides new insights and a viable path for the design,fabrication,and integration of high-performance μLEDs on Si for a broad range of applications in on-chip optical communication and emerging augmented reality/mixed reality devices,and so on.

关键词： polarization diodes strain

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Efficiency-based Pareto Optimization of Building Energy Consumption and Thermal Comfort:A Case Study of a Residential Building in Bushehr,Iran

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Journal of Thermal Science 2024年第3期33卷 1037-1054页

作者： Masoud NASOURI navid DELGARM Department of Environment University of TehranAras International CampusP.O.Box ***TehranIran Department of Mechanical and Aerospace Engineering Malek-Ashtar University of TechnologyP.O.Box 83145/115IsfahanIran

In Iran,the intensity of energy consumption in the building sector is almost 3 times the world average,and due to the consumption of fossil fuels as the main source of energy in this sector,as well as the lack of optimal design of buildings,it has led to excessive release of toxic gases into the *** research develops an efficient approach for the simulation-oriented Pareto optimization(SOPO)of building energy efficiency to assist engineers in optimal building design in early design *** this end,EnergyPlus,as one of the most powerful and well-known whole-building simulation programs,is combined with the Multi-objective Ant Colony Optimization(MOACO)algorithm through the JAVA programming *** a result,the capabilities of JAVA programming are added to EnergyPlus without the use of other plugins and third *** evaluate the effectiveness of the developed method,it was performed on a residential building located in the hot and semi-arid region of *** obtain the optimum configuration of the building under investigation,the building rotation,window-to-wall ratio,tilt angle of shading device,depth of shading device,color of the external walls,area of solar collector,tilt angle of solar collector,rotation of solar collector,cooling and heating setpoints of heating,ventilation,and air conditioning(HVAC)system are chosen as decision ***,the building energy consumption(BEC),solar collector efficiency(SCE),and predicted percentage of dissatisfied(PPD)index as a measure of the occupants'thermal comfort level are chosen as the objective *** single-objective optimization(SO)and Pareto optimization(PO)are *** obtained results are compared to the initial values of the basic *** optimization results depict that the PO provides optimal solutions more reliable than those obtained by the SOs,owing to the lower value of the deviation ***,the optimal solutions extracted through the PO are depicted in the

关键词： building energy consumption thermal comfort collector efficiency simulation-oriented pareto optimization

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Investigating the Role of Bushehr Nuclear Power Plants(BNPPs)in Line with Achieving the Perspective of Sustainable Energy Development in Iran

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Journal of Thermal Science 2022年第5期31卷 1392-1406页

作者： NASOURI Masoud DELGARM navid Department of Environment Aras International CampusUniversity of TehranTehran***Iran Department of Mechanical Engineering Malek-Ashtar University of TechnologyIsfahan83145/115Iran

In line with achieving the outlook of Sustainable Energy Development(SED),Iran intends to increase the share of clean power to at least 8%of the country’s capacity by the end of *** research aims to investigate the role and share of Bushehr Nuclear Power Plants(BNPP-1,2,3)in achieving the SED perspective of Iran,which has never been examined so *** this connection,the comparative analyses of various power plants(PPs)of Iran including nuclear,fossil fuel,biomass,wind,solar thermal,photovoltaic,geothermal,and hydro PPs are carried out and *** main indicators of SED such as Levelized Cost of Electricity(LCOE)metric,grid-level system cost,investment cost,external cost,average CO_(2) equivalent emission,ecosystem impact,required land area,required water,preservation of natural resources,human health,created jobs,international cooperation,social acceptance and Corporate Social Responsibility(CSR),and energy-water hub are thoroughly *** statistical data used in the present study are extracted based on the authors’experiences gained during the construction,operation and maintenance(O&M)of BNPP-1,the energy-environment balance sheets of Iran,as well as the design documents of ***,the gathered data are evaluated using MatLab programing language and analyzed in terms of comparative *** evaluations of BNPP-1 performance within the framework of SED indicate that BNPP-1 has little effect on ecosystems and is among the lowest greenhouse gases emitters compared to other Iran’s PPs so that it annually prevent the release of 0.7 million tonnes of carbon,SO_(x),and NO_(x) compared to a gas-fired ***,the cost analysis shows that the external cost of BNPP-1 is nearly zero and the grid-level cost is approximately 3 USD/(MW·h)which is much lower than that for renewable *** per the LCOE metric and the cost of fuel supply,BNPP-1 is cost-competitive with other Iran’s *** nuclear fuel cost of BNPP-1 is nearly 49 million USD per

关键词： BNPP Sustainable Energy Development(SED) economic social environment

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An analytical framework for the incorporation of non-orthogonal pilots in massive MIMO systems

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Digital Communications and Networks 2024年第5期10卷 1267-1279页

作者： navid Pourjafari Jalil Seifali Harsini Department of Electrical Engineering The University of Guilan

Training-based cellular communication systems use orthogonal pilot sequences to limit pilot ***,the orthogonality constraint imposes a certain pilot length,and therefore,in communication systems with a large number of users,time-frequency resources are wasted significantly in the training *** cellular massive MIMO systems,the time-frequency resources can be used more efficiently by replacing the orthogonal pilots with shorter non-orthogonal pilot sequences in such a way that more space is available for the transmission of additional data symbols,and thus achieving higher data *** course,the use of non-orthogonal pilots introduces additional pilot contamination,so the performance improvement could be achieved under certain system conditions,which are thoroughly investigated in this *** first provide a performance analysis framework for the uplink of cellular massive MIMO systems in which the effect of user pilot non-orthogonality has been analytically *** this framework,we derive analytical expressions for the channel estimation,user Signal-to-Interference-plus-Noise-Ratio(SINR),and the average channel capacity per *** then use the proposed framework to evaluate the achievable spectral efficiency gain obtained by replacing orthogonal pilots with non-orthogonal *** particular,the existing trade-off between pilot lengths and the additional data symbols that can be transmitted by reducing the number of pilot symbols,is numerically quantified over a wide range of system parameters.

关键词： Massive MIMO Non-orthogonal pilots Cellular systems Performance analysis

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Influence of glycine additive on corrosion and wear performance of electroplated trivalent chromium coating

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International Journal of Minerals,Metallurgy and Materials 2020年第4期27卷 544-554页

作者： navid Mehdipour Milad Rezaei Zeynab Mahidashti Department of Materials and Metallurgical Engineering Amirkabir University of Technology(Tehran Polytechnic)Hafez Ave.P.O.Box 15875-4413TehranIran

The aim of this study is to evaluate the effect of various molar ratios of glycine to chromium salt(Gly:Cr)and different current densities on the corrosion and wear behaviors of Cr(III)electroplated *** morphology and thickness of the coatings were investigated by scanning electron *** wear properties of the coatings were studied using pin on disk and hardness tests,while corrosion behavior of the coatings was identified using linear polarization,small amplitude cyclic voltammetry,and electrochemical impedance spectroscopy *** increasing the glycine concentration,a structure with low crack density was *** all molar ratios,maximum thickness and current efficiency was observed at a current density of 150 mA·cm?*** the electrochemical methods had a consistent result,and maximum corrosion resistance of approximately 16000Ω·cm2 was obtained in the case of Gly:Cr=3:1 and current density of 200 mA·cm?2.

关键词： electrodeposition trivalent chromium glycine corrosion resistance

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Enhanced degradation of reactive dyes using a novel carbon ceramic electrode based on copper nanoparticles and multiwall carbon nanotubes

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Chinese Journal of Chemical Engineering 2020年第1期28卷 318-327页

作者： Fatemeh Jafari navid Nasirizadeh Mohammad Mirjalili Department of Textile and Polymer Engineering Yazd BranchIslamic Azad UniversityYazdIran

A novel carbon ceramic electrode consisting of Cu NPs and MWCNT was developed to treat reactive orange 84(RO84) wastewater using ultrasound-assisted electrochemical degradation. The proposed electrode generated more hydroxyl radicals than non-nanoparticle electrodes did. In addition, a new electrochemical sensor was applied to determine residue RO84 in an aqueous medium during discoloration. This sensor is based on a glassy carbon electrode modified with gold nanourchins and graphene oxide and can detect RO84 concentration in the range of 1.0–1200 μmol·L^-1 with the detection limit of 0.03 μmol·L^-1. The degradation effects of the modified electrode on RO84 were evaluated systematically with different initial pH values, time durations, and amounts of Cu NPs and MWCNT. The results suggested that the removal efficiency of RO84 was approximately 83% after120 min of electrolysis in a phosphate buffer with pH 8.0 using a carbon ceramic electrode made with 4.0 wt%Cu NPs and 4.0 wt% MWCNT. The possible mechanism of RO84 degradation was monitored by gas chromatography–mass spectrometry, and degradation pathways were proposed.

关键词： Electrochemical degradation Carbon ceramic nanocomposite Reactive dye Copper nanoparticles

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TS Fuzzy Prediction-based SVC Compensation of Wind Farms Flicker:A Dual-UKF Approach

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CSEE Journal of Power and Energy Systems 2022年第6期8卷 1594-1602页

作者： Saeedeh Ketabipour Haidar Samet navid Vafamand School of Electrical and Computer Engineering Shiraz UniversityShirazIran Department of Electrical Engineering Eindhoven University of TechnologyEindhoventhe Netherlands

Fast fluctuations in wind farm power produce voltage flicker in the *** way to mitigate the flicker is to place a static VAr compensator(SVC).Due to the operating delay of SVCs,it is essential to predict the wind farm reactive ***,a novel fuzzy nonlinear modeling approach is suggested and used in the one-step-ahead prediction of the power *** base of the developed fuzzy modeling is the Takagi-Sugeno fuzzy representation and a dual-unscented Kalman filter(D-UKF).In other words,a nonlinear TS fuzzy system is trained online via the *** forecasted value is used as the SVC’s reference signal.A large amount of actual data gathered from a wind farm is used for the performance *** data is collected in winter and summer for different climate *** the actual data,a current source with changing amplitude and phase which is updated every half-cycle,is used to model the wind *** results,including the flicker indices,confirm the improvement in the SVC’s performance.

关键词： SVC voltage flicker wind farm

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Charge transfer and bipolar charging of particles in a bubbling fluidized bed

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Particuology 2021年第1期19卷 109-115页

作者： Mahshad Manafi Reza Zarghami navid Mostoufi Multiphase Systems Research Laboratory School of Chemical EngineeringCollege of EngineeringUniversity of TehranP.O.Box 11155-4563TehranIran

Particle-particle and particle-wall collisions in gas-solid fluidized beds lead to charge accumulation on *** work evaluated the effect of fluidization time on charge transfer and bipolar charging(charge separation)and their influence on hydrodynamic structures in a fluidized *** were performed with glass beads and polyethylene particles in a glass *** pressure fluctuations and net electrostatic charge of particles were measured during *** and short-time Fourier transforms were used to analyze pressure *** results revealed that bipolar charging is the dominant tribocharging mechanism in a bed of glass *** charging in a bed of particles with a narrow size distribution does not affect either hydrodynamic structures or the transition velocity to the turbulent regime.A large difference between the work functions of the wall and particle in the bed of polyethylene particles leads to high charge *** of a stagnant particle layer on the wall eventually causes the energy of macro-structures to increase to its *** longer fluidization times,the macro-structural energy decreases and bubbles shrink until the electrostatic charge reaches the equilibrium *** results well describe the effect of fluidization time on hydrodynamic structures.

关键词： Contact electrification Charge transfer Bipolar charging Pressure fluctuations Fluidization structures

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Particle size distribution in a multi-zone circulating fluidized bed polymerization reactor

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Particuology 2024年第10期93卷 291-299页

作者： Mohammadhossein Hadadiyan navid Mostoufi Reza Marandi Process Design and Simulation Research Centre School of Chemical EngineeringCollege of EngineeringUniversity of TehranP.O.Box 11155-4563TehranIran Polymer Research Group Petrochemical Research and Technology CompanyNational Petrochemical CompanyP.O.Box 14358/84711TehranIran

This research focuses on modeling a multi-zone circulating reactor(MZCR)in the polypropylene production *** these reactors,designed for polyolefin production,small catalyst particles(20–300μm)initiate polymerization in the presence of monomer *** reactor consists of two main regions:the riser and the *** riser operates in the fast fluidization and the downer is in the moving bed *** the two-fluid model with the Eulerian-Eulerian approach,the dynamics of both solid and gas phases were modeled by applying Newton's laws of motion and assuming spherical *** population balance of particles within the reactor was also coupled with the equations of *** simultaneous solution of these equations provides valuable insights into particle and fluid behavior,revealing trends such as the growth of polymer ***,the impact of various operating conditions was *** study also examined the effects of design parameters(gas inlet velocity,average inlet diameter,and temperature)on the system *** instance,it was shown that in the case where the solid circulation flux is 30 kg/(m^(2) s)the velocity of particles in the bed increases from 0.4 at the inlet to 1.1 m/s in the fully developed zone,when it is 43 kg/(m^(2) s)the velocity of particles increases from 0.3 to 1.4 m/s,and when it is 55 kg/(m^(2) s),it is increased from 0.22 to 1.5 m/***,trends in particle size distribution based on temperature adjustments were *** study showed that higher temperatures accelerate the polymerization reaction rate,promoting faster growth kinetics and the formation of larger particles.

关键词： Fluidization Polymerization Gas-solid flow Multi-zone circulating reactor(MZCR) CFD-PBM Two-fluidmodel

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A wavelet packet based method for adaptive single-pole auto-reclosing

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Journal of Zhejiang University-Science C(Computers and Electronics) 2010年第12期11卷 1016-1024页

作者： Sadegh JAMALI navid GHAFFARZADEH Centre of Excellence in Power Systems Automation and Operation Iran University of Science and Technology Tehran Iran

We present a new algorithm for adaptive single-pole auto-reclosing of power transmission lines using wavelet packet transform. The db8 wavelet packet decomposes the faulted phase voltage waveform to obtain the coefficients of the nodes 257, 259 to 262. An index is then defined from the sum of the energy coefficients of these nodes. By evaluating the index, transient and permanent faults, as well as the secondary arc extinction instant, can be identified. The significant advantage of the proposed algorithm is that it does not need a threshold level and therefore its performance is independent of fault location, line parameters, and operating conditions. Moreover, it can be used in transmission lines with reactor compensation. The proposed method has been successfully tested under a variety of fault conditions on a 400 kV overhead line of the Iranian National Grid using the Electro-Magnetic Transient Program (EMTP). The test results validated the algorithm’s ability in distinguishing between transient arcing and permanent faults and determining the instant of secondary arc extinction.

关键词： Adaptive auto-reclosing Arcing faults Permanent faults Transmission lines Wavelet packet transform

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