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微电网电能质量分层控制及其关键技术

大功率变流技术 2017年第2期 1-10,26页

作者：孟乐轩赵鑫 mehdi savaghebi 韩民晓 Josep Guerrero 奥尔堡大学能源系华北电力大学电力工程系北京102206

电力电子变换器的广泛使用使得利用并网逆变器进行电能质量调整成为可能,但这也对并网逆变器的控制提出了更多的要求。文章基于现有的研究成果与未来微电网及配电网的电能质量要求,提出了一种三层式管理与控制系统结构,并对每个层次的... 详细信息

电力电子变换器的广泛使用使得利用并网逆变器进行电能质量调整成为可能,但这也对并网逆变器的控制提出了更多的要求。文章基于现有的研究成果与未来微电网及配电网的电能质量要求,提出了一种三层式管理与控制系统结构,并对每个层次的主要目标与核心技术进行了阐述。这种多层式的控制方法仍有待于研究者进行更多更深入的研究,最后对后续的工作进行了展望。

关键词：分布式发电微电网电能质量分层控制

Visualizing traumatic brain injury:ocular clues for diagnosis and assessment

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Neural Regeneration Research 2025年第5期20卷 1399-1400页

作者： Morteza Abyadeh Vivek Gupta Yuyi You Joao A.Paulo mehdi Mirzaei ProGene Technologies Pty Ltd SydneyNSWAustralia Department of Clinical Medicine Faculty of MedicineHealth and Human SciencesMacquarie Medical SchoolMacquarie UniversityMacquarie ParkNorth RydeSydneyNSWAustralia Department of Cell Biology Harvard Medical SchoolBostonMAUSA

Traumatic brain injury (TBI) is defined as damage to the brain resulting from an external sudden physical force or shock to the *** is considered a silent public health epidemic causing significant death and disability *** were 64,000 TBI related deaths reported in the USA in 2020,with about US$76 billion in direct and indirect medical costs annually.

关键词： diagnosis ocular injury

A Study on Flame Forming of Bowl Shaped Surface with Various Spiral Irradiating Schemes

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Acta Mechanica Solida Sinica 2016年第3期29卷 328-336页

作者： mehdi Safari Department of Mechanical Engineering Arak University of Technology

In this paper, various strategies of spiral irradiating scheme for the flame forming of a bowl shaped surface are investigated experimentally and numerically. Experimental work is performed using a flame torch integrated with a 2-axis CNC workstation. The ABAQUS implicit solver is used in the numerical simulation. Three different strategies of the spiral irradiating scheme are investigated for the flame forming of a bowl shaped surface. The first strategy is the Simple spi- ral irradiating scheme, the second is the Rotational spiral irradiating scheme, and the third is the Symmetrical-Rotational spiral irradiating scheme. The results show that using the Symmetrical- Rotational spiral irradiating scheme, a bowl shaped surface with the maximum deformation can be produced, followed by using the Rotational scheme, and the Simple spiral scheme. It is also concluded from the results that the spiral irradiating scheme with Symmetrical-Rotational, Rota- tional and Simple spiral schemes lead to the maximum symmetries in the produced bowl shaped surface, respectively. All the numerical results are in good agreement with the experimental ob- servations.

关键词： flame forming bowl shaped surface spiral irradiating strategy

BLUNT CRACK-TIP ELASTOPLASTIC ZONE OF MIXED MODE FRACTURE

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Acta Mechanica Solida Sinica 2014年第5期27卷 531-541页

作者： mehdi Khojastehpour Department of Biosystems Engineering Ferdowsi University of Mashhad

This article discusses the characterization of fracture process zone at the tip of a blunt crack in elastoplastic materials under mixed mode loading. The analysis includes the description of elastoplastic zone geometry around the blunt crack tip for predicting crack growth direction. The deformed zone appearing at the crack front is described by presenting a criterion based on the subloading surface concept falling within the framework of unconventional plasticity. The mixed mode crack propagates along the minimum value of the elastoplastic region. The present solutions are reduced to those previously reported in literature, when the elastic perfectly plastic material is considered.

关键词： crack fracture elastic plastic materials stress concentration

Human reliability analysis in maintenance team of power transmission system protection

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Protection and Control of Modern Power Systems 2020年第1期5卷 290-302页

作者： mehdi Tavakoli mehdi Nafar Department of Electrical Engineering Marvdasht BranchIslamic Azad UniversityMarvdashtIran

The requirement for reliable electrical energy supply increases continuously because of its vital role in our ***,events due to various factors in the power grid can cause energy supply to be *** of these factors is human error and thus human reliability analysis is a serious element in the *** first step is to identify the roots of human error,on which there has been limited research in this *** this paper,the potential and actual causes of human error in maintenance teams of power transmission system protection are identified and predicted within a framework of human factors analysis and classification system ***,human error factors are ranked to help improve human *** proposed method is implemented in the Fars Electricity Maintenance Company.

关键词： Power transmission system protection Maintenance teams Human reliability HFACS method

Movement of Intransitive Permutation Groups Having Maximum Degree

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Chinese Annals of Mathematics,Series B 2012年第1期33卷 143-148页

作者： mehdi ALAEIYAN mehdi REZAEI School of Mathematics Iran University of Science and Technology

Let G be a permutation group positive integer. Then the movement of G on a set Ω with no fixed points in Ω, and m be a is defined as move（G）：=supГ{[Г^9 ／Г｜｜g ∈ G}. It F was shown by Praeger that if move（G） = m, then ｜Ω｜ ≤ 3m ＋ t - 1, where t is the number of G-orbits on ≤. In this paper, all intransitive permutation groups with degree 3m ＋ t - 1 which have maximum bound are classified. Indeed, a positive answer to her question that whether the upper bound ｜Ω｜ = 3m ＋ t - 1 for ｜Ω｜ is sharp for every t 〉 1 is given.

关键词： Intransitive permutation groups Bounded movement Orbit

Kinetic studies of the oxidative coupling of methane over the Mn/Na_2WO_4/SiO_2 catalyst

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Journal of Natural Gas Chemistry 2009年第1期18卷 25-34页

作者： Seyed mehdi Kamali Shahri Seyed mehdi Alavi Reaction Engineering Lab. Chemical Engineering Department Iran University of Science and Technology Tehran-Iran

Oxidative coupling of methane is a direct way to obtain C2 hydrocarbon, and Mn-Na-W/SiO2 catalyst is the most promising among all the catalysts. The 2%Mn/5%Na2WO4/SiO2 catalyst was prepared by the incipient wetness impregnation method. A 7-step heterogeneous reaction model of the oxidative coupling of methane to C2 hydrocarbons was conducted by co-feeding methane and oxygen at a total pressure of 1 bar over the catalyst. The kinetic measurements were carried out in a micro-catalytic fixed bed reactor. The kinetic data were obtained at the appropriate range of reaction conditions （4 kPa〈Po2 〈20 kPa, 20 kPa〈PcH4〈80 kPa, 800 ℃〈T〈900℃）. The proposed reaction kinetic scheme consists of three primary and four consecutive reaction steps. The conversions of hydrocarbons and carbon oxides were evaluated by applying Langmuir-Hinshelwood type rate equations. Power-law rate equation was applied only for the water-gas shift reaction. In addition, the effects of operating conditions on the reaction rate were studied. The proposed kinetic model can predict the conversion of methane and oxygen as well as the yield of C2 hydrocarbons and carbon oxides with an average accuracy of ± 15%.

关键词： kinetic model oxidative coupling of methane reaction rate

Cognitive Power Management in Wireless Sensor Networks

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Journal of Computer Science & Technology 2015年第6期30卷 1306-1317页

作者： Seyed mehdi Tabatabaei Vesal Hakami mehdi Dehghan Department of Computer Engineering and Information Technology Amirkabir University of Technology Tehran 16846-13114 Iran

Dynamic power management （DPM） in wireless sensor nodes is a well-known technique for reducing idle energy consumption. DPM controls a node＇s operating mode by dynamically toggling the on/off status of its units based on predictions of event occurrences. However, since each mode change induces some overhead in its own right, guaranteeing DPM＇s eificiency is no mean feat in environments exhibiting non-determinism and uncertainty with unknown statistics. Our solution suite in this paper, collectively referred to as cognitive power management （CPM）, is a principled attempt toward enabling DPM in statistically unknown settings and gives two different analytical guarantees. Our first design is based on learning automata and guarantees better-than-pure-chance DPM in the face of non-stationary event processes. Our second solution caters tor an even more general setting in which event occurrences may take on an adversarial character. In this case, we formulate the interaction of an individual mote with its environment in terms of a repeated zero-sum game in which the node relies on a no-external-regret procedure to learn its mini-max strategies in an online fashion. We conduct numerical experiments to measure the performance of our schemes in terms of network lifetime and event loss percentage.

关键词： wireless sensor network cognitive power management learning automata external regret zero-sum game

Porosity parameters in biomaterial science: Definition, impact, and challenges in tissue engineering

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Frontiers of Materials Science 2021年第3期15卷 352-373页

作者： mehdi EBRAHIMI Biomedical and Tissue Engineering Prince Philip Dental HospitalThe University of Hong KongHong KongChina

Porosity parameters are one of the structural properties of the extracellular microenvironment that have been shown to have a great impact on the cellular phenotype and various biological activities such as diffusion of fluid,initial protein adsorption,permeability,cell penetration and migration,ECM deposition,angiogenesis,and rate and pattern of new tissue *** heterogeneity of the study protocols and research methodologies do not allow reliable meta-analysis for definite *** such,despite the huge available literature,no generally accepted consensus is defined for the porosity requirements of specific tissue engineering ***,based on the biomimetic approach,the biological substitutes should replicate the 3D local microenvironment of the recipient site with matching porosity parameters to best support local cells during tissue ***,the porosity of biomaterials should mimic the porosity of the substituting natural tissue and match the clinical *** analysis of the impact of architectures(i.e.,porosity)on biophysical,biochemical,and biological behaviors will support designing smart biomaterials with customized architectural and functional properties that are patient and defect site-specific.

关键词： porosity pore size pore geometry topography tissue engineering