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Acta Mathematica Scientia 2013年第5期33卷 1329-1346页

作者： Vagif GULIYEV Ali AKBULUT Yagub MAMMADOV Department of Mathematics Ahi Evran University institute of Mathematics and Mechanics of NAS of Azerbaijan nakhchivan teacher-training institute

In the article we consider the fractional maximal operator Mα, 0 ≤α 〈 Q on any Carnot group G （i.e., nilpotent stratified Lie group） in the generalized Morrey spaces Mp,φ（G）, where Q is the homogeneous dimension of G. We find the conditions on the pair （φ1, φ2） which ensures the boundedness of the operator Ms from one generalized Morrey space Mp,φ1 （G） to another Mq,φ2 （G）, 1. 〈 p ≤q 〈 ∞. 1/p - 1/q = α/Q, and from the space M1,φ1 （G） to the weak space Wq,φ2 （G）, 1 〈 q 〈 ∞, 1 - 1/q = α/Q. Also find conditions on the φ which ensure the Adams type boundedness of the Ms from M α （G） from Mp,φ^1/p（G）to Mq,φ^1/q（G） for 1 〈p〈q〈∞ and fromM1,φ（G） toWMq,φ^1/q（G）for 1〈q〈∞. In the case b ∈ BMO（G） and 1 〈 p 〈 q 〈 ∞, find the sufficient conditions on the pair （φ1, φ2） which ensures the boundedness of the kth-order commutator operator Mb,α,k from Mp,φ1 （G） to Mq,φ2（G） with 1/p - 1/q = α/Q. Also find the sufficient conditions on the φ which ensures the boundedness of the operator Mb,α,k from Mp,φ^1/p（G） tom Mp,φ^1/p （G） for 1 〈p〈q〈∞. In all the cases the conditions for the boundedness of Mα are given it terms of supremaltype inequalities on （φ1, φ2） and φ , which do not assume any assumption on monotonicity of （φ1, φ2） and φ in r. As applications we consider the SchrSdinger operator -△G ＋ V on G, where the nonnegative potential V belongs to the reverse Holder class B∞（G）. The MB,φ1 - Mq,φ2 estimates for the operators V^γ（-△G ＋ V）^-β and V^γ△↓G（-△G ＋ V）^-β are obtained.

关键词： Carnot group fractional maximal function generalized Morrey space Schrodinger operator BMO space

Microstructure and Impression Creep Properties of Ca-Containing AS31 Magnesium Alloy

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Acta Metallurgica Sinica(English Letters) 2016年第12期29卷 1089-1097页

作者： Mohammad Badri Seyyed Mehdi Miresmaeili Bahram Nami Shahid Rajaee teacher training University Lavizan TehranIran

The effect of Ca addition on the microstructure and impression creep properties of AS31 magnesium alloy was investigated in the current study. The results showed that the microstructure of AS31 alloy is composed of α（Mg） phase, massive Mg17Al12 and some Chinese script Mg2Si compounds. Addition of 2 wt% Ca to AS31 alloy resulted in complete elimination of MglTAl12 phase and formation of Al2Ca compound. Ca improved the alloy＇s creep properties especially at higher temperature. Improvement in the creep properties was attributed to the elimination of soft Mg17Al12 and formation of thermally stable Al2Ca compound. According to the obtained stress exponent and creep activation energy, pipe diffusion climb-controlled creep was estimated as the dominant creep mechanism and Ca had no influence on the dominant mechanism.

关键词： Magnesium-aluminum-silicon alloy Calcium Microstructure Creep Mechanism

Improvement of Grain Size and Dome Height of Microalloyed Steels Using Taguchi Method Based on Grey Relational Grade in Controlled Rolling

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Journal of Iron and Steel Research International 2013年第12期20卷 115-123页

作者： Mohsen Ayaz Daavood Mirahmadi Khaki Nasrollah Bani Mostafa Arab Department of Mechanical Engineering Shahid Rajaee Teacher Training University Department of Materials Engineering Shahid Rajaee Teacher Training University

An efficient approach was introduced for improving the condition of major controlled rolling process pa- rameters of roughing, finishing and coiling temperatures and optimizing these parameters to obtain minimum grain size and maximum dome height simultaneously. Taguchi method combined with grey relational analysis was applied to achieve optimum grain size and dome height during controlled rolling process. For this purpose, four levels for the above temperatures were chosen and sixteen experiments were conducted based on orthogonal array of Taguchi meth- od. Based on Taguchi approach, signal-to-noise （S/N） ratios were calculated and used in order to obtain the opti- mum levels for every input parameter. Analysis of variance revealed that finishing and coiling temperatures have the maximum effect on the grain size and dome height of microalloyed steels. The confirmation tests with the optimal levels of parameters indicated that the grain size and dome height of controlled rolled microalloyed steels can be im- proved effectively through this approach.

关键词： controlled rolling microalloyed steel dome height grain size Taguchi method grey relational grade

Decentralized Voltage Control of Power Systems Using Multi-agent Systems

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Journal of Modern Power Systems and Clean Energy 2020年第2期8卷 249-259页

作者： Hamidreza Shahbazi Farid Karbalaei the Department of Electrical Engineering Shahid Rajaee Teacher Training UniversityTehranIran the Faculty of Electrical Engineering Shahid Rajaee Teacher Training UniversityTehranIran

*** our proposed smart self-healing method,two types of control agents are defined,namely master and local,which are applied in two *** the first step,the power system returns to the normal state after fault *** after a fault detection in a power system,the system is divided into three subsystems using spectral graph *** is conducted based on reactive power flow in transmission *** each subsystem,a local control agent and a performance index(PI)are *** the PI of a subsystem exceeds its threshold limit,the local control agent uses the Sugeno fuzzy system to intelligently select and apply control *** the second step as performed by the master control agent,the power system is transformed to an optimal state by solving the optimization *** on a 39-bus New England reveal the effective performance of the proposed method.

关键词： Emergency voltage control partitioning multi-agent systems fuzzy systems

The plurality effect of topographical irregularities on site seismic response

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Earthquake Engineering and Engineering Vibration 2019年第3期18卷 521-534页

作者： Saeed Ghaffarpour Jahromi Sama Karkhaneh Department of Civil Engineering Shahid Rajaee Teacher Training University

Topography can have signifi cant eff ects on seismic ground response during an earthquake because topographic irregularities cause considerable diff erences between the seismic waves emitted by the source and the waves reaching the ground surface. When a seismic motion happens in a topographically irregular area, seismic waves are trapped and refl ected between the topographic features. Therefore, the interaction between topographies can amplify seismic ground response. In order to reveal how interaction between topographies infl uences seismic response, several numerical fi nite element studies have been performed by using the ABAQUS program. The results show that topographic features a greater distance between the seismic source and the site would cause greater seismic motion amplifi cation and is perceptible for the hills far away from the source and the ridges. Also, site acceleration response is impacted by surrounding topography further than site velocity and displacement response.

关键词： Topography eff ects surrounding topography site seismic response ABAQUS Program and PLAXIS Program

ANALYTIC SOLUTIONS OF SIMPLE WAVES

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Applied Mathematics and Mechanics(English Edition) 1993年第11期14卷 1057-1062页

作者：李国彬 teacher's training institute of Kunming Kunming

B. Riemann furnished the general solution of simple waves in 1860[1] But it is difficult to find out the exact forms of the arbitrary function contained in the general solution which must satisfy boundary or initial conditions. For this reason it is inconvenient to probe into the characteristics of concrete problems. In this paper the analytic solutions of simple waves are afforded according to the geometric theory of quasi-linear partial differential equation, and they are determined with boundary or initial conditions. By using these solutions the specific properties of certain flows are discussed and novel results are obtained.

关键词： simple waves analytic solutions discontinuity

Effect of inlet temperature and equivalence ratio on HCCI engine performance fuelled with ethanol:Numerical investigation

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Journal of Central South University 2016年第1期23卷 122-129页

作者： Alireza Rahbari Department of Mechanical Engineering Shahid Rajaee Teacher Training University (SRTTU)

A numerical model is presented to investigate the performance of homogeneous charge compression ignition(HCCI) engines fueled with ethanol. Two approaches are studied. On one hand, two-step reaction mechanisms with Arrhenius reaction rates are implemented in combustion chemistry modeling. On the other hand, a reduced mechanism containing important reactions of ethanol involving heat release rate and reaction rates compatible with experimental data is employed. Since controls of combustion phenomenon and ignition timing are the main issues of these engines, the effects of inlet temperature and equivalence ratio as the controlling factors on the operating parameters such as ignition timing, burn duration, in-cylinder temperature and pressure of HCCI engines are explored. The results show that the maximum predicted pressures for thermodynamic model are about 71.3×10~5 Pa and 79.79×10~5 Pa, and for chemical kinetic model, they are about 71.48×10~5 Pa and 78.123×10~5 Pa, fairly comparable with corresponding experimental values of 72×10~5 Pa and 78.7×10~5 Pa. It is observed that increasing the initial temperature advances the ignition timing, decreases the burn duration and increases the peak temperature and pressure. Moreover, the maximum temperature and pressure are associated with richer mixtures.

关键词： HCCI engine ethanol two-step reaction mechanism model chemical kinetic model

AUTOMATIC AUGMENTED GALERKIN ALGORITHMS FOR FREDHOLM INTEGRAL EQUATIONS OF THE FIRST KIND

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Acta Mathematica Scientia 1997年第1期17卷 69-84页

作者： S.Abbasbandy E.Babolian teacher training UNIV INST MATHTEHRAN 15614IRAN

In recent papers, Babolian & Delves [2] and Belward[3] described a Chebyshev series method for the solution of first kind integral equations. The expansion coefficients of the solution are determined as the solution of a mathematical programming *** method involves two regularization parameters, Cf and r, but values assigned to these parameters are heuristic in nature. Essah & Delves[7] described an algorithm for setting these parameters automatically, but it has some difficulties. In this paper we describe three iterative algorithms for computing these parameters for singular and non-singular first kind integral equations. We give also error estimates which are cheap to compute. Finally, we give a number of numerical examples showing that these algorithms work well in practice.

关键词： Fredholm integral equations Galerkin method Regularization parameters Error estimation Ill-Posed problems Product of chebyshev series

Forced oscillations and stability analysis of a nonlinear micro-rotating shaft incorporating a non-classical theory

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Acta Mechanica Sinica 2018年第5期34卷 970-982页

作者： S.Ali Ghasabi Mohammadreza Arbabtafti Majid Shahgholi Mechanical Engineering Faculty Shahid Rajaee Teacher Training UniversityTehranIran

In this paper,the stability and bifurcation analysis of symmetrical and asymmetrical micro-rotating shafts are investigated when the rotational speed is in the vicinity of the critical *** the help of Hamilton's principle,nonlinear equations of motion are derived based on non-classical theories such as the strain gradient *** the dynamic modeling,the geometric nonlinearities due to strains,and strain gradients are *** bifurcations and steady state solution are compared between the classical theory and the non-classical *** is observed that using a non-classical theory has considerable effect in the steady-state response and bifurcations of the *** a result,under the classical theory,the symmetrical shaft becomes completely stable in the least damping coefficient,while the asymmetrical shaft becomes completely stable in the highest damping *** the modified strain gradient theory,the symmetrical shaft becomes completely stable in the least total eccentricity,and under the classical theory the asymmetrical shaft becomes completely stable in the highest total ***,it is shown that by increasing the ratio of the radius of gyration per length scale parameter,the results of the non-classical theory approach those of the classical theory.

关键词： Strain gradient theory Micro-rotating shaft Stability Nonlinear oscillation Bifurcation Multiple scales method

Assessing the seismic behavior of steel moment frames equipped by elliptical brace through incremental dynamic analysis(IDA)

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Earthquake Engineering and Engineering Vibration 2020年第2期19卷 435-449页

作者： Ghasemi Jouneghani Abbas Haghollahi Department of Civil Engineering Shahid Rajaee Teacher Training UniversityTehranIran

Incremental dynamic analysis and nonlinear static pushover analysis are carried out on a performance-based design to determine the seismic demands and capacities of an elliptic braced moment resisting frame(ELBRF).The objective is to assess ductility,overstrength and response modification factors in a modern steel-braced structural system based on incremental dynamic *** integrated system is connected to a beam and column with an appropriate length while providing enough architectural space to allow for an opening without having the common problems associated with architectural spaces in braced *** different classes of buildings are considered on soil type *** dynamic analysis,nonlinear static pushover analysis and incremental nonlinear dynamic analysis related to 12 records from past earthquakes are carried out using OpenSees *** factors of ductility,overstrength and response modification are calculated for this *** values of 9.5 and 6.5 are found and suggested only for the response modification factor for ELBRF systems in allowable stress and ultimate limit state methods,*** fragility curves are plotted for the first time for this type of bracing,which contributes to the assessment of building seismic damage.

关键词： elliptic brace response modification factor overstrength factor ductility factor incremental dynamic analysis,fragility curve