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Application of hybrid robust three-axis attitude control approach to overactuated spacecraft——A quaternion based model

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Journal of Central South University 2016年第7期23卷 1740-1753页

作者： A.h.Mazinan Department of Control Engineering Faculty of Electrical Engineering South Tehran BranchIslamic Azad University(IAU)

A novel hybrid robust three-axis attitude control approach, namely hRTAC, is considered along with the well-known developments in the area of space systems, since there is a consensus among the related experts that the new insights may be taken into account as decision points to outperform the available materials. It is to note that the traditional control approaches may generally be upgraded, as long as a number of modifications are made with respect to state-of-the-art, in order to propose high-precision outcomes. Regarding the investigated issues, the robust sliding mode finite-time control approach is first designed to handle three-axis angular rates in the inner control loop, which consists of the pulse width pulse frequency modulations in line with the control allocation scheme and the system dynamics. The main subject to employ these modulations that is realizing in association with the control allocation scheme is to be able to handle a class of overactuated systems, in particular. The proportional derivative based linear quadratic regulator approach is then designed to handle three-axis rotational angles in the outer control loop, which consists of the system kinematics that is correspondingly concentrated to deal with the quaternion based model. The utilization of the linear and its nonlinear terms, simultaneously, are taken into real consideration as the research motivation, while the performance results are of the significance as the improved version in comparison with the recent investigated outcomes. Subsequently, there is a stability analysis to verify and guarantee the closed loop system performance in coping with the whole of nominal referenced commands. At the end, the effectiveness of the approach considered here is highlighted in line with a number of potential recent benchmarks.

关键词： three-axis angular rates and rotations sliding mode finite-time control approach proportional derivative based linearquadratic regulator approach dynamics and kinematics of overactuated spacecraft

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Bio-fluid flow analysis based on heat transfer and variable viscosity

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Applied Mathematics and Mechanics(English Edition) 2019年第7期40卷 1029-1040页

作者： h.SADAF Department of Basic Sciences and humanities College of Electrical and Mechanical EngineeringNational University of Sciences and TechnologyIslamabad

This study investigates the cilia transport phenomenon from the perspectives of the heat transfer and variable viscosity in a bending channel. The rightward wall is maintained at a temperature of T0, and the leftward wall has a temperature of T1. Each wall has a metachronal wave that travels along its wall. The structures of the ciliary assemblies are calculated by the well-known simplifying suppositions of the large wavelength and the small Reynolds number approximation. The flow phenomenon for the Newtonian fluid is described as a function of cilia and a metachronal wave velocity. The pressure rise is calculated with MAThEMATICA. The theme of the cilia beating flow is inspected with scheming plots, and its features are discussed at the end of the article.

关键词： cilia-driven flow curved channel temperature dependent viscosity metachronal wave heat transfer exact solution

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Two-Dimensional Linear Dependencies on the Coordinate Time-Dependent Interaction in Relativistic Non-Commutative Phase Space

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Communications in Theoretical Physics 2015年第9期64卷 263-268页

作者： h.Sobhani h.hassanabadi Physics Department University of Shahrood

In this paper, the Non-Commutative phase space and Dirac equation, time-dependent Dirac oscillator are introduced. After presenting the desire general form of a two-dimensional linear dependency on the coordinate timedependent potential, the Dirac equation is written in terms of Non-Commutative phase space parameters and solved in a general form by using Lewis–Riesenfield invariant method and the time-dependent invariant of Dirac equation with two-dimensional linear dependency on the coordinate time-dependent potential in Non-Commutative phase space has been constructed, then such latter operations are done for time-dependent Dirac oscillator. In order to solve the differential equation of wave function time evolution for Dirac equation and time-dependent Dirac oscillator which are partial differential equation some appropriate ordinary physical problems have been studied and at the end the interesting result has been achieved.

关键词： Non-Commutative phase space Dirac equation time-de

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Fore-aft asymmetry of the ~2h(n,γ)~3h at very low energies

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Chinese Physics C 2013年第9期37卷 13-18页

作者： h.Khalili h.Sadeghi Department of Physics Faculty of ScienceArak University

We have used the recent effective field theory （EFT） which is constructed from two- and three-nucleon interactions, using minimal substitution in the momentum dependence of these interactions. We present the calcula- tions of the fore-aft asymmetry of γ-rays in the reaction 2h（n,γ）3h which are based on EFT up to next-to-next-to leading order （N2LO）. The results are compared with the recently reported calculations and measurements of the fore-aft asymmetry of T-rays from neutron-deuteron radiative capture. The calculated fore-aft asymmetry of the nd radiative capture process above deuteron breakup threshold is in good agreement with the available experimental data up to 20 MeV.

关键词： effective field theory neutron-deuteron radiative capture photonuclear observables fore-aft asymmetry

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Relations between SMBh Parameters and Jet Generation and Efficiency in Blazars

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Research in Astronomy and Astrophysics 2023年第11期23卷 67-83页

作者： h.Zhang h.J.Zhang Department of Physics Yunnan Normal UniversityKunming 650092China

We analyzed the relationship between several basic parameters describing supermassive black holes such as jet power,black hole spin,accretion disk magnetic field,black hole mass,*** found that there is a general correlation between these parameters,such as jet power is significantly positively correlated with black hole spin,while black hole mass is significantly negatively correlated with black hole *** apprehend these relationships,we consider the Blandford–Znajek model to be superior to the Blandford–Payne *** is also found that the intrinsic gamma luminosity of the FSRQs has a positive correlation with the accretion disk magnetic field,while the intrinsic gamma luminosity of the BL Lacs has a negative correlation with the accretion disk magnetic field.A feedback effect may exist between accretion disk accretion rate and magnetic field,which may be the key to the evolution between BL Lacs and *** is no significant difference in the jet power and jet generation efficiency of FSRQs and BL Lacs,which suggests that the jets are generated by the same *** contribution rate of accretion rate to jet generation efficiency is high,while the contribution rate of accretion rate to jet power is very low.

关键词： galaxies:evolution galaxies:fundamental parameters galaxies:jets

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Microstructure and Mechanical Properties in Dissimilar Butt Friction Stir Welding of Severely Plastic Deformed Aluminum AA 1050 and Commercially Pure Copper Sheets

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Journal of Materials Science & Technology 2014年第8期30卷 826-834页

作者： h.Barekatain M.Kazeminezhad A.h.Kokabi Department of Materials Science and Engineering Sharif University of TechnologyAzadi AvenueTehranIran

In this study,AA 1050 aluminum alloy and commercially pure copper in annealed and severely plastic deformed conditions were *** technique used for imposing the severe strain to the sheets was constrained groove pressing（CGP） *** annealed and severely plastic deformed sheets were subjected to friction stir welding（FSW） at different rotation and traverse *** was placed in advancing *** offset of approximately 1 mm was used toward Al side for all welds.A range of welding parameters which can lead to acceptable welds with appropriate mechanical properties was *** the FSWed CGPed samples,it was observed that the welding heat input caused grain growth and decrease in hardness value at Al side of the stir *** was found that,generally the weakest parts of weld joints of annealed and CGPed samples were Al base metal and stir zone,*** investigations showed that several forms of intermetallic compounds were produced.

关键词： Friction stir welding Severe plastic deformation Aluminum Copper Intermetallics

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Stochastic Distribution Control of Singular Systems: Output PDF Shaping

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自动化学报 2005年第1期31卷 151-160页

作者： h.YUE A.J.A.LEPRAND h.WANG InstituteofAutomation ChineseAcademyofSciencesBeijing100080P.R.China ControlSystemsCentre TheUniversityofManchesterManchesterM601QDUK instituteofAutomation ChineseAcademyofSciencesBeijing100080P.R.China／／ControlSystemsCentreTheUniversityofManchesterManchesterM601QDUK

This paper presents a new algorithm designed to control the shape of the output probability density function (PDF) of singular systems subjected to non-Gaussian input. The aim is to select a control input uk such that the output PDF is made as close as possible to a given *** on the B-spline neural network approximation of the output PDF, the control algorithm is formulated by extending the developed PDF control strategies of non-singular systems to singular systems. It has been shown that under certain conditions the stability of the closed-loop system can be guaranteed. Simulation examples are given to show the effectiveness of the proposed control algorithm.

关键词：随机分布控制单系统 PDF显示输出动态随机系统概率密度函数

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Sliding Wear Behavior of a Grey Cast Iron Surface Remelted by TIG

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Journal of Materials Science & Technology 2009年第5期25卷 622-628页

作者： h.Mohamadzadeh h.Saghafian Sh.Kheirandish Department of Metallurgy and Materials Engineering Iran University of Science and TechnologyTehranIran

The sliding wear behavior of a grey cast iron surface remelted by tungsten inert gas （TIG） was studied and compared with the unremelted one in the current work. To evaluate the wear behavior a Pin-on-Disk wear test machine was used. Pins which were prepared from the samples with the remelted layers of different thicknesses of 1.2, 1.8, 2.5 and 3 turn were worn on an AISID3 steel counterface having a hardness of 63hRC under the applied loads of 54, 76 and gg N at a constant sliding velocity of 0.45 m/s. Scanning electron microscopy （SEM） equipped with energy dispersive X-ray analysis （EDS） and X-ray diffraction （XRD） techniques were used to characterize worn surface and subsurface and also wear debris obtained from the wear tests under different test conditions. Results showed that surface remelted grey cast iron have better wear properties for all applied normal loads in comparison with unremelted ones. Microscopic studies on the worn surfaces and subsurfaces of samples revealed that dominant wear mechanism for surface remelted samples was mild oxidative, while it was severe for unremelted samples. Increasing remelted layer thickness and then forming grosser microstructure lead to a decline of wear properties, whereas lower thickness of remelted layer with finer microstructure due to having higher cooling rate through remelting process can withstand better against wear.

关键词： Grey cast Iron Surface remelted Tungsten inert gas (TIG) Wear

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Temperature and Thermal Stress Distribution for Metal Mold in Squeeze Casting Process

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Journal of Materials Science & Technology 2008年第3期24卷 347-350页

作者： C.h.Lee S.h.Lee Institute of Technology and Science Chung-Ang University

In the squeeze casting process, loaded high pressure （over approximately 200 MPa） and high temperature influence the thermo-mechanical behavior and performance of the used metal mold. Therefore, to safely maintain the metal molds, the thermo-mechanical characteristics （temperature and thermal stress） of metal mold in the squeeze casting must be investigated. In this paper, temperature and thermal stress distribution of steel mold in squeeze casting process were investigated by using a three-dimensional non-steady heat conduction analysis and a three-dimensional thermal elastic-plastic analysis considering temperature-dependent thermophysical and mechanical properties of the steel mold.

关键词： Squeeze casting Steel mold Thermal stress Thermo-Mechanical analysis

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Adaptive Functional Projective Lag Synchronization of a hyperchaotic Rossler System

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Chinese Physics Letters 2009年第9期26卷 69-72页

作者： Tae h. Lee Ju h. Park Nonlinear Dynamics Group Department of Electrical Engineering Yeungnam University 214-1 Dae-Dong Kyongsan 712-749 Republic of Korea

We explain the functional projective lag synchronization of a hyperchaotic Rossler system with four unknown parameters, where the output of the master system lags behind the output of the slave system proportionally. Based on Lyapunov stability theory, an active control method and adaptive control law are employed to make the states of two hyperchaotic Rossler systems asymptotically synchronized. Finally, some numerical examples are provided to show the effectiveness of our results.

关键词： No English Keyword

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