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Characteristics of Positive Ions in the Sheath region of magnetized Collisional Electronegative Discharges

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Plasma Science and Technology 2014年第6期16卷 552-556页

作者： m.m.HATAmI A.r.NIKNAm Physics Department of K.N.Toosi University of Technology Laser-Plasma research Institute of Shahid Beheshti University G.C.

A hydrodynamic model is used to investigate the characteristics of positive ions in the sheath region of a low-pressure magnetized electronegative discharge. Positive ions are modeled as a cold fluid, while the electron and negative ion density distributions obey the Boltzmann distribution with two different temperatures. By taking into account the ion-neutral collision effect in the sheath region and assuming that the momentum transfer cross section has a power law dependence on the velocity of positive ions, the sheath formation criterion （modified Bohm＇s criterion） is derived and it is shown that there are specified maximum and minimum limits for the ion mach number m. Considering these two limits of m, the behaviors of electrostatic potential, charged particle density distributions and positive ion velocities in the sheath region are studied for different values of ion-neutral collision frequency.

关键词： electronegative plasma hydrodynamic model magnetized plasma sheath,Bohm's criterion

An improved displacement-based adaptive pushover procedure based on factor modal combination rule

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Earthquake Engineering and Engineering Vibration 2014年第2期13卷 223-241页

作者： Abbasnia r Tajik Davoudi A maddah m.m Department of Civil Engineering Iran University of Science and Technology

An accurate estimation of the applied load pattern is an essential component in each pushover procedure. recently, a number of adaptive pushover methods have been proposed in which the effects of the higher modes as well as the progressive changes in the dynamic characteristics of structures are taken into account to compute the applied load pattern. The basic shortcoming of these advanced pushover methods is related to employing the quadratic modal combination rule, whereby the sign reversals of the modal load vectors are suppressed. In this study, an improved displacement-based adaptive pushover method is developed in which the applied load pattern is computed using the factor modal combination rule(FmC). In the proposed procedure, multiple load patterns, depending on the number of the modes considered, are determined in order to take into account the sign reversals of different modal load vectors. The accuracy of the proposed method is verifi ed for seven moment resisting frame buildings of 3, 9 and 20 stories with regularity or vertically geometric and mass irregularities subjected to 60 earthquake ground motion records. The results showed that the proposed methodology is capable of reproducing the peak dynamic responses with very good accuracy.

关键词： adaptive pushover higher modes sign reversal factor modal combination rule

Energy states of the Hulthen plus Coulomb-like potential with position-dependent mass function in external magnetic fields

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Chinese Physics B 2018年第2期27卷 234-238页

作者： m Eshghi r Sever S m Ikhdair Young researchers and Elite Club Central Tehran Branch Islamic Azad University Department of Physics Middle East Technical University Department of Physics Faculty of Science An-Najah National University Department of Electrical Engineering Near East University

We need to solve a suitable exponential form of the position-dependent mass （PDm） Schr6dinger equation with a charged particle placed in the Hulthen plus Coulomb-like potential field and under the actions of the external magnetic and Aharonov-Bohm （AB） flux fields. The bound state energies and their corresponding wave functions are calculated for the spatially-dependent mass distribution function of interest in physics. A few plots of some numerical results with respect to the energy are shown.

关键词： Schr6dinger equation Hulthen plus Coulomb-like potential position-dependent mass distributionfunctions perpendicular magnetic and Aharonov-Bohm flux fields

recognition of the Projective Special Linear Group over GF(3)

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Acta mathematica Sinica,English Series 2010年第3期26卷 477-488页

作者： m.r.DArAFSHEH School of mathematics College of Science University of Tehran

Let P be a finite group and denote by w（P） the set of its element orders. P is called k-recognizable by the set of its element orders if for any finte group G with ω（G） =ω（P） there are, up to isomorphism, k finite groups G such that G ≌P. In this paper we will prove that the group Lp（3）, where p 〉 3 is a prime number, is at most 2-recognizable.

关键词： element order projective special linear group recognition by spectrum

Charaeterizability of the Group ~2D_p(3) by its Order Components,Where p≥5 is a Prime Number Not of the Form 2~m+1

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Acta mathematica Sinica,English Series 2008年第7期24卷 1117-1126页

作者： m.r.DArAFSHEH School of mathematics College of ScienceUniversity of TehranTehranIran

The author will prove that the group ^2Dp（3） can be uniquely determined by its order components, where p ≠ 2^m ＋ 1 is a prime number, p ≥ 5. more precisely, if OC（G） denotes the set of order components of G, we will prove OC（G） = OC（^2Dp（3）） if and only if G is isomorphic to ^2Dp（3）. A main consequence of our result is the validity of Thompson＇s conjecture for the groups under consideration.

关键词： prime graph order component linear group

Electrodeless plasma thrusters for spacecraft: a review

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Plasma Science and Technology 2017年第8期19卷 1-24页

作者： S N BATHGATE m m m BILEK D r mCKENZIE Applied and Plasma Physics School of PhysicsUniversity of Sydney

The physics of electrodeless electric thrusters that use directed plasma to propel spacecraft without employing electrodes subject to plasma erosion is reviewed. Electrodeless plasma thrusters are potentially more durable than presently deployed thrusters that use electrodes such as gridded ion,Hall thrusters, arcjets and resistojets. Like other plasma thrusters, electrodeless thrusters have the advantage of reduced fuel mass compared to chemical thrusters that produce the same thrust. The status of electrodeless plasma thrusters that could be used in communications satellites and in spacecraft for interplanetary missions is examined. Electrodeless thrusters under development or planned for deployment include devices that use a rotating magnetic field; devices that use a rotating electric field; pulsed inductive devices that exploit the Lorentz force on an induced current loop in a plasma; devices that use radiofrequency fields to heat plasmas and have magnetic nozzles to accelerate the hot plasma and other devices that exploit the Lorentz force. Using metrics of specific impulse and thrust efficiency, we find that the most promising designs are those that use Lorentz forces directly to expel plasma and those that use magnetic nozzles to accelerate plasma.

关键词： spacecraft a review propellant Lorentz thrust rotating radiofrequency erosion presently exploit

Swelling-induced finite bending of functionally graded pH-responsive hydrogels:a semi-analytical method

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Applied mathematics and mechanics(English Edition) 2019年第5期40卷 679-694页

作者： m.SHOJAEIFArD m.r.BAYAT m.BAGHANI School of mechanical Engineering College of Engineering University of Tehran

recently, pH-sensitive hydrogels have been utilized in the diverse applications including sensors, switches, and actuators. In order to have continuous stress and deformation ?elds, a new semi-analytical approach is developed to predict the swelling induced?nite bending for a functionally graded(FG) layer composed of a pH-sensitive hydrogel,in which the cross-link density is continuously distributed along the thickness direction under the plane strain condition. Without considering the intermediary virtual reference,the initial state is mapped into the deformed con?guration in a circular shape by utilizing a total deformation gradient tensor stemming from the inhomogeneous swelling of an FG layer in response to the variation of the pH value of the solvent. To enlighten the capability of the presented analytical method, the ?nite element method(FEm) is used to verify the accuracy of the analytical results in some case studies. The perfect agreement con-?rms the accuracy of the presented method. Due to the applicability of FG pH-sensitive hydrogels, some design factors such as the semi-angle, the bending curvature, the aspect ratio, and the distributions of deformation and stress ?elds are studied. Furthermore, the tangential free-stress axes are illustrated in deformed con?guration.

关键词： pH-sensitive hydrogel functionally graded(FG)layer finite bending semianalytical solution finite element method(FEm)

A novel chaotic butterfly network topology based block scrambling and crown graph based bit-wise diffusion for image encryption

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Frontiers of Computer Science 2021年第2期15卷 193-195页

作者： Vidhya r Brindha m Department of Computer Science and Engineering National Institute of TechnologyTamilnadu620015India

1 Introduction and contributions Due to,rapid growth in multimedia and internet technology,multimedia information such as images,videos,etc are shared via *** the confidentiality of information i.e,information security has become more *** this purpose,different techniques are approached in order to achieve confidentiality of *** traditional symmetric encryption techniques like AES[1],DES confidentiality can be *** encryption schemes like DES and AES which are private key encryption methods and other public key methods like rSA(rivest Shamir Adleman)algorithm are time consuming.

关键词： multimedia encryption network

Comparative orotomy of the Archean Superior and Phanerozoic Altaid orogenic systems

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National Science review 2023年第2期10卷 20-48页

作者： Timothy m.Kusky A.m.Celal ?eng?r Center for Global Tectonics School of Earth Sciences and State Key Laboratory for Geological Processes and Mineral ResourcesChina University of Geosciences Badong National Observatory and research Station for Geohazards Ministry of Education China University of Geosciences Department of Geological Engineering Middle East Technical University Eurasia Institute of Earth Sciences Istanbul Technical University Department of Geology Faculty of Mines Istanbul Technical University

We compare and contrast the materials and mechanisms of continental crustal growth in the largest preserved regions of Phanerozoic and Archean juvenile additions to the crust,to test for similarities or differences in the formation of continents through *** accomplish this through a comparison of map patterns,lithological contents,and structural and metamorphic evolution of the Phanerozoic Altaid orogenic system of Asia,with the Archean Superior Province of the North American Craton,using a method termed comparative *** orogenic systems consist of collages of curvilinear belts of eroded arcs,some older continental slivers,and vast tracts of former subduction/accretionary *** contain numerous shreds of portions of the ophiolite suite,slivers of island and continental arcs,and accreted oceanic plateau,all intruded by multiple magmatic suites during or between multiple deformation events,then sliced by large transcurrent fault systems and bent into large oroclinal *** make this comparison because the Superior Province is a typical Archean craton that was later,in the P aleoproterozoic,incorporated into the larger North American Craton,and has occupied a central position in several super continents(*** and Nuna,which then formed the core of Columbia,rodinia,Laurentia and Pangea) during its *** it is the largest single fragment of Archean continental cratonic lithosphere preserved on Earth,the Superior Province is widely regarded as a testing ground for how Earth’s continental crust was ***,the Altaids encompass the largest region of crustal growth for the *** comparison with the Altaids is needed,as in recent years many myths about how the planet may have responded to higher heat production and flow in the Archean have emerged,because of trends in the science where regional geology is ignored in favor of numerical models,isotopic proxies for assumed models of chemical behavior for crust-for

关键词： Altaids superior province ophiolite subduction strike-slip