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An error-free protocol for quantum entanglement distribution in long-distance quantum communication

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Chinese Science Bulletin 2011年第7期56卷 618-625页

作者： SALEMIAN Shamsolah MOHAMMADNEJAD shahram Nanoptronics Research Center Department of Electronics and Electrical Engineering Iran University of Science and Technology

Quantum entanglement distribution is an essential part of quantum communication and computation protocols. Here, linear optic elements are employed for the distribution of quantum entanglement over a long distance. Polarization beam splitters and wave plates are used to realize an error-free protocol for broadcasting quantum entanglement in optical quantum communication. This protocol can determine the maximum distance of quantum communication without decoherence. Error detection and error correc-tion are performed in the proposed scheme. In other words, if there is a bit flip along the quantum channel, the end stations (Alice and Bob) can detect this state change and obtain the correct state (entangled photon) at another port. Existing general error detec-tion protocols are based on the quantum controlled-NOT (CNOT) or similar quantum logic operations, which are very difficult to implement experimentally. Here we present a feasible scheme for the implementation of entanglement distribution based on a linear optics element that does not need a quantum CNOT gate.

关键词：光量子通信量子纠缠协议长距离分发错误检测量子逻辑运算光学元件

Globally stable and high-performance Internet congestion control through a computational inspiration from nature

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Science China(Information Sciences) 2011年第6期54卷 1251-1263页

作者： AMALI shahram ANALOUI Morteza Computer Engineering Department University of Mohaghegh Ardabili Computer Engineering Department Iran University of Science and Technology

There are many reasons to worry that the current congestion control schemes in the Internet may be reaching its limits. Since the nature is a source of excellent solutions for complex problems, this work attempts to solve the congestion control problem, by adopting some biological principles and mechanisms. The current work proposes that the congestion problem in the Internet can be addressed through an inspiration from the population control tactics in nature. Toward this idea, each flow (W ) in the network is viewed as a species whose population size matches congestion window size of the flow. By this assumption, congestion control problem is redefined as population control of flow species. This paper defines a three-trophic food chain analogy in congestion control area, and gives a model to control population size of W species within this food chain. We call this model BICCTT and show mathematically, it is stable and efficient regardless of the link capacity, the round-trip delay, and number of flows. Extensive packet-level simulations in ns-2, show that BICCTT operates better than TCP/RED and XCP in both typical and high bandwidth-delay environments. BICCTT achieves fair bandwidth allocation, high utilization, small queue size, and near-zero packet drops. It does not maintain any per-flow state in routers and have low computational loads per packet, which makes it scalable.

关键词： nature-inspired algorithm congestion control TCP stability

Modified-DBR-based semi-omnidirectional multilayer anti-reflection coating for tandem solar cells

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Chinese Physics B 2014年第2期23卷 609-613页

作者： Ali Bahrami shahram Mohammadnejad Nima Jouyandeh Abkenar Nanoptronics Research Center Department of Electrical and Electronics EngineeringIran University of Science and Technology

In this paper, multilayer antireflection coatings are designed by modifying the thickness of two and three paired layer distributed Bragg reflector （DBR） structure. Our proposed DBR-based structures show antireflection behaviors, in spite of the reflection treatment in traditional DBR structures. Firstly, the proposed structures are designed to be equivalent to the theoretical ideal triple-layer （TL） antireflection coating （ARC）. Therefore, the problem of finding a suitable material for the middle layer of triple structure is solved. Simulation results show the significant equivalency for the reflectance of proposed structures to the ideal TL ARC at the same wavelengths and incident angles. Also, the design of the structure is changed in order to present the constant reflectance coefficient over a wide range of wavelengths. This structure enhances the omni-directionality of the multilayer ARC.

关键词： antireflection coating distributed bragg reflector solar cell

Structure of ADAFs in a general large-scale B-field:the role of wind and thermal conduction

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Research in Astronomy and Astrophysics 2013年第1期13卷 87-98页

作者： Amin Mosallanezhad Mehdi Khajavi shahram Abbassi Center for Excellence in Astronomy & Astrophysics (CEAA-RIAAM) School of Physics Damghan University Department of Physics School of SciencesFerdowsi University of Mashhad School of Astronomy Institute for Research in Fundamental Sciences

We have explored the structure of a hot flow bathed in a general large-scale magnetic field. The importance of outflow and thermal conduction on the self-similar structure of a hot accretion flow has been investigated. We consider the additional 2 2 2 magnetic parameters are the Alfv6n sound speeds in three directions of cylindrical coordinates. In comparison to the accretion disk without winds, our results show that the radial and rotational velocities of the disk become faster, but the disk becomes cooler because of the angular momentum and energy flux which are taken away by the winds. Moreover, thermal conduction opposes the effect of winds and not only decreases the rotational velocity but also in- creases the radial velocity as well as the sound speed of the disk. In addition, we study the effect of the global magnetic field on the structure of the disk. Our numerical re- suits show that all the components of a magnetic field can be important and they have a considerable effect on velocities and vertical structure of the disk.

关键词： accretion: accretion flow -- wind: outflow -- thermal conduction

Artinianness and Attached Primes of Formal Local Cohomology Modules

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Algebra Colloquium 2014年第2期21卷 307-316页

作者： Mohammad Hasan Bijan-Zadeh shahram Rezaei Department of Mathematics Faculty of Science Payame Noor University Iran

Let a be an ideal of a local ring （R, m） and A4 a finitely generated R-modu｜e. In this paper we study the Artinianness properties of formal local cohomology modules and we obtain the lower and upper bounds for Artinianness of formal local cohomology modules. Additionally, we determine the set AttR a dim M（M） and we show that the set of all non-isomorphic formal local cohomology modules a dim M（M） is finite.

关键词： Artinianness properties attached primes formal local cohomology local co-homology

Numerical simulation of the Hall effect in magnetized accretion disks with the Pluto code

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Research in Astronomy and Astrophysics 2014年第1期14卷 93-103页

作者： Mohammad Nakhaei Ghasem Safaei shahram Abbassi School of Physics Damghan University School of Astronomy Institute for Research in Fundamental Sciences Department of Physics School of SciencesFerdowsi University of Mashhad

We investigate the Hall effect in a standard magnetized accretion disk which is accompanied by dissipation due to viscosity and magnetic resistivity. By consider- ing an initial magnetic field, using the PLUTO code, we perform a numerical magne- tohydrodynamic simulation in order to study the effect of Hall diffusion on the physi- cal structure of the disk. Current density and temperature of the disk are significantly modified by Hall diffusion, but the global structure of the disk is not substantially affected. The changes in the current densities and temperature of the disk lead to a modification in the disk luminosity and radiation.

关键词： Hall effect -- accretion disks

Adsorption of Folic Acid on the Single-walled Carbon Nanotubes: AIM and NBO Analyses via DFT

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Chinese Journal of Structural Chemistry 2015年第8期34卷 1161-1169页

作者： Shahla Hamedani shahram Moradi Hossein Aghaie Department of Chemistry Science and Research Branch Islamic Azad University Department of Chemistry Tehran North Branch Islamic Azad University

In the present work, the behavior of folic acid （FA） molecule adsorbed onto single-walled carbon nanotube （SWCNT） was examined using the DFT-B3LYP/6-31G＊ level. In order to obtain information about the binding features of SWCNT as adsorbent with FA molecule, several studies, including the structural and electronic parameters and also the Atoms in Molecules （AIM） analysis, were performed. It was observed that the FA molecule via hydrogen bond prefers to adsorb on SWCNT with adsorption energy of about -18.70 kcal/mol. The molecular orbitals （HOMO and LUMO）, natural bond orbital （NBO）,analysis, and density of states （DOS） plot indicated that a charge about 0.032 [ e [ is transferred from the FA molecule to the nanotube. After solvation energy calculations, it was found that the presence of a polar solvent causes an increase in FA adsorption on the single-walled carbon nanotube. Topological features such as electron energy density （Hc） and Laplacian of the electron density （V2p~） demonstrate partial covalent nature for H（ll6）...O（10） interaction in the FA/SWCNT complex. According to the calculated results, the single-walled carbon nanotubes are expected to be a potential efficient adsorbent for the adsorption of folic acid drug and also can be used as a suitable drug delivery vehicle within biological systems.

关键词： adsorption, carbon nanotube, folic acid, DFT, AIM

Investigation of Microstructure and Corrosion of TiNbTaZrMo High-Entropy Alloy in the Simulated Body Fluid

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Journal of Bionic Engineering 2021年第1期18卷 118-127页

作者： Arash Shokrgozar Navi shahram Etemadi Haghighi Mohammad Haghpanahi Amir Momeni Deparment of mechanical engineering Science and Research branchIslamic Azad UniversityTehran ***Oran Department of mechanical engineering Iran University of Science and TechnologyTehran 13114-16846Iran Materials Science and Engineering Department Hamedan University of TechnologyHlamedan ***Iran

Microstructures and corrosion of TiNbTaZrMo(Ti_(20)Nb_(20)Ta_(20)Zr_(20)Mo_(20))High-Entropy Alloy(HEA)were investigated in the Simu-lated Body Fluid(SBF).Microstructure of this alloy was investigated by X-Ray Difiraction(XRD)and Scanning Electron Microscopy(SEM)*** observations confirmed the presence of two bcc phases as the major matrix as well as another minor phase in themicrostructure of the *** of some elements,such as tantalum,niobium,and molybdenum in the dendritic branches and thepresence of zirconium and titanium in the inter-dendritic branches were clearly evidenced by Energy Dispersive X-ray(EDX)*** importance of corrosion of implant alloys in the human's body,elctrochemical impedance and cyclic polarization tests werepcerformed on the alloy in *** the corrosion tests,corrosion potential,current,and resistance were obtained as E_(corr)=-0.42 V,i_(corr)=0.34μA·cm^(-2),and R_(p)=27.44 k ohm·cm^(2),*** results revealed that the rate of corrosion in TiNbTaZrMo HEA is about 26 times better than that of Ti_(6)Al_(4)V ***,both alloys had no pitting corrosion in the SBF solution.

关键词： HEA SBF implant material electrochemical impedance test Nyquist polarization test

Efficient keyword search over graph-structured data based on minimal covered r-cliques

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Frontiers of Information Technology & Electronic Engineering 2020年第3期21卷 448-465页

作者： Asieh GHANBARPOUR Khashayar niknafs Hassan NADERI School of Computer Engineering Iran University of Science and TechnologyTehran 13114-16846Iran Department of Computer Engineering University of Sistan and BaluchestanZahedan 98167-45845Iran

Keyword search is an alternative for structured languages in querying graph-structured data.A result to a keyword query is a connected structure covering all or part of the queried *** textual coverage and structural compactness have been known as the two main properties of a relevant result to a keyword *** previous works examined these properties after retrieving all of the candidate results using a ranking function in a comparative ***,this needs a time-consuming search process,which is not appropriate for an interactive system in which the user expects results in the least possible *** problem has been addressed in recent works by confining the shape of results to examine their coverage and compactness during the ***,these methods still suffer from the existence of redundant nodes in the retrieved *** this paper,we introduce the semantic of minimal covered r-clique(MCCr)for the results of a keyword query as an extended model of existing *** propose some efficient algorithms to detect the MCCrs of a given *** algorithms can retrieve a comprehensive set of non-duplicate MCCrs in response to a keyword *** addition,these algorithms can be executed in a distributive manner,which makes them outstanding in the field of keyword *** also propose the approximate versions of these algorithms to retrieve the top-k approximate MCCrs in a polynomial *** is proved that the approximate algorithms can retrieve results in *** experiments on two real-world datasets confirm the efficiency and effectiveness of the proposed algorithms.

关键词： Keyword search Graph mining Information retrieval Database Clique