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    Demo paper: Atomic bonded cross-chain debt

    , Article 3rd IEEE International Conference on Blockchain and Cryptocurrency, ICBC 2021, 3 May 2021 through 6 May 2021 ; 2021 ; 9781665435789 (ISBN) Khajehpour, A ; Bagheri, F ; Abdi, M ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021
    Atomic Bonded Cross-chain Debt (ABCD) is the first non-custodial smart-contract-independent cross-chain atomic bond. Theoretical aspects of ABCD have been presented in the International Conference on Blockchain Technology and Applications (ICBTA) and won the best presentation award. It is the first time a demo of Atomic Bonded Cross-chain Debt is presented. © 2021 IEEE  

    Hydrogen storage in single- and multi-walled carbon nanotubes and nanotube bundles

    , Article Australian Journal of Basic and Applied Sciences ; Volume 5, Issue 7 , 2011 , Pages 483-490 ; 19918178 (ISSN) Hamidi, S ; Golnabi, H ; Sharif University of Technology
    This article describes the hydrogen storage capacity in different carbon nanotubes. The hydrogen storage capacities in the armchair, zigzag, and chiral nanotubes are investigated. The hydrogen storing capacities as a function of the carbon nanotube (CNT) diameter are investigated for the single-walled (SWNT), multi-walled (MWNT), and CNT bundles and results are compared. Hydrogen storage capacity in SWNTs is increased by increasing the nanotube diameter. For diameter d=0.3887 nm of (5,0) CNT the hydrogen capacity is 0.99%, while for the (17,17) SWNT with a diameter d=2.289 nm the capacity is increased to 5.06%. In comparison of different MWNTs for a common external diameter d=1.6064 nm the... 

    Experimental flow visulization of single swirl spray pattern at various pressure drops

    , Article 39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit 2003, Huntsville, AL, 20 July 2003 through 23 July 2003 ; 2003 ; 9781624100987 (ISBN) Ghorbanian, K ; Ashjaee, M ; Soltani, M. R ; Mesbahi, M. H ; Morad, M. R ; Sharif University of Technology
    An experimental investigation of the flow field of pressure swirl atomizers for different pressure drops is performed. Two experimental methods are employed. For low injection pressures, a visual study is conducted while for higher pressures the velocity components and size of the droplets are measured by using Phase Doppler Anemometer. The spray formation, spray cone angle, and breakup length are visually investigated. Velocity and size of the droplets are measured on a plane of measurement along the axis of the spray so that the properties are carried out in a radial direction as a function of both pressure drop and axial distance from the nozzle. Self-similar mean axial velocity profiles... 

    Spray characteristics of a liquid-liquid coaxial swirl atomizer at different mass flow rates

    , Article Aerospace Science and Technology ; Volume 9, Issue 7 , 2005 , Pages 592-604 ; 12709638 (ISSN) Soltani, M. R ; Ghorbanian, K ; Ashjaee, M ; Morad, M. R ; Sharif University of Technology
    An experimental investigation is performed to explore the characteristics of sprays produced by a liquid-liquid coaxial swirl injector in a non-combusting environment. Phase Doppler anemometry is used for the measurement of velocity and Sauter Mean Diameter of droplets across and along the injection axis for various inner- and outer mass flow rates. Results of the combined spray are compared with those of inner- and/or outer spray alone. The results indicate that the inner injector has a larger influence on the flow field of the combined spray compared to the outer one. Further, the maximum velocity of the combined spray is close to the center of the spray thickness and the velocity... 

    Efficient electromagnetically induced phase grating via quantum interference in a four-level N-type atomic system

    , Article Journal of the Optical Society of America B: Optical Physics ; Vol. 31, issue. 10 , 2014 , p. 2430-2437 Naseri, T ; Sadighi-Bonabi, R ; Sharif University of Technology
    An electromagnetically induced phase grating controlled by spontaneous generated coherence (SGC) in a fourlevel N-type atomic system is studied. The results indicate that the diffraction efficiency of the phase grating is dramatically enhanced due to the existence of SGC, and an efficient electromagnetically induced phase grating can be obtained. A novel result is considerable improvement of the intensity of higher-order diffractions via relative phase between applied laser fields. Furthermore, it is found that the frequency detuning of the switching and coupling fields with the corresponding atomic transition, incoherent pumping, and the interaction length can improve the efficiency of the... 

    Drastic influence of boron atom on the acidity of alcohol in both gas phase and solution phase, a DFT study

    , Article Journal of Theoretical and Computational Chemistry ; Volume 12, Issue 1 , 2013 ; 02196336 (ISSN) Kheirjou, S ; Mehrpajouh, S ; Fattahi, A ; Sharif University of Technology
    In this study, the drastic influence of the boron atom on the acidity of alcohol has been considered. The calculated ΔHacid (320.9-338.1 kcal/mol) and pKa range of boron containing alcohol (-0.1-9.4) indicate that the boronation of alcohol leads to considerable enhancement of its acidity. For instance, we have obtained the ΔHacid values 338.1, 335.2 kcal/mol and the pKa values 4.12, 2.81 for BH 2CH2OH, BF2CH2OH alcohols, respectively, which are much smaller than that of CH3OH (with ΔHacid = 374.9 kcal/mol and pKa = 15). The increase in the acidity of boronated alcohol can be related to the stabilization of alkoxy ion due to overlap of unoccupied orbital of boron atom with the electron pairs... 

    Theoretical investigation of electromagnetically induced phase grating in RF-driven cascade-Type atomic systems

    , Article Applied Optics ; Volume 54, Issue 11 , 2015 , Pages 3484-3490 ; 1559128X (ISSN) Sadighi Bonabi, R ; Naseri, T ; Sharif University of Technology
    A new scheme for investigating electromagnetically induced grating in four-level cascade-Type of 87Rb cold atoms is presented. The novel result indicates that the diffraction efficiency of phase grating is dramatically enhanced due to the presence of an RF-driven field and a diffraction efficiency up to 34% can be obtained. Furthermore, it is found that the frequency detuning of the applied laser fields with the corresponding atomic transition and the interaction length can improve the efficiency of the phase grating in the present atomic model. This work has potential applications in all-optical communication processes  

    Experimental and theoretical study on spray behaviors of modified bio-ethanol fuel employing direct injection system

    , Article Thermal Science ; Volume 21 , 2017 , Pages 475-488 ; 03549836 (ISSN) Ghahremani, A ; Ahari, M ; Jafari, M ; Saidi, M. H ; Hajinezhad, A ; Mozafari, A ; Sharif University of Technology
    One of the key solutions to improve engine performance and reduce exhaust emissions of internal combustion engines is direct injection of bio-fuels. A new modified bio-ethanol is produced to be substituted by fossil fuels in gasoline direct injection engines. The key advantages of modified bio-ethanol fuel as an alternative fuel are higher octane number and oxygen content, a long-chain hydro-carbon fuel, and lower emissions compared to fossil fuels. In the present study spray properties of a modified bio-ethanol and its atomization behaviors have been studied experimentally and theoretically. Based on atomization physics of droplets dimensional analysis has been performed to develop a new... 

    The formation of atomic nanoclusters on graphene sheets

    , Article Nanotechnology ; Volume 20, Issue 13 , 2009 ; 09574484 (ISSN) Neek Amal, M ; Asgari, R ; Rahimi Tabar, M. R ; Sharif University of Technology
    The formation of atomic nanoclusters on suspended graphene sheets has been investigated by employing a molecular dynamics simulation at finite temperature. Our systematic study is based on temperature-dependent molecular dynamics simulations of some transition and alkali atoms on suspended graphene sheets. We find that the transition atoms aggregate and make various size nanoclusters distributed randomly on graphene surfaces. We also report that most alkali atoms make one atomic layer on graphene sheets. Interestingly, the potassium atoms almost deposit regularly on the surface at low temperature. We expect from this behavior that the electrical conductivity of a suspended graphene doped by... 

    Acquisition of high precision images for non-contact atomic force microscopy via direct identification of sample height

    , Article 2005 ASME International Mechanical Engineering Congress and Exposition, IMECE 2005, Orlando, FL, 5 November 2005 through 11 November 2005 ; Volume 74 DSC, Issue 2 PART B , 2005 , Pages 1335-1342 ; 0791842169 (ISBN); 9780791842164 (ISBN) Pishkenari, H. N ; Jalili, N ; Meghdari, A ; Sharif University of Technology
    Atomic force microscopes (AFM) can image and manipulate sample properties at the atomic scale. The non-contact mode of AFM offers unique advantages over other contemporary scanning probe techniques, especially when utilized for reliable measurements of soft samples (e.g., biological species). The distance between cantilever tip and sample surface is a time varying parameter even for a fixed sample height, and hence, difficult to identify. A remedy to this problem is to directly identify the sample height in order to generate high precision, atomic-resolution images. For this, the microcantilever is modeled by a single mode approximation and the interaction between the sample and cantilever... 

    LiClO4 · 3H2O promoted highly regioselective ring-opening of epoxides with thiols under neutral conditions [electronic resource]

    , Article Catalysis Communications ; 2006, Volume 7, Issue 4, Pages 224–227 Azizi, N. (Najmodin) ; Saidi, M. R ; Sharif University of Technology
    A simple, rapid, atom economy and highly efficient procedure has been developed for thiolysis of epoxides by aromatic and aliphatic thiols under solvent-free conditions. A high regioselectivity in favor of nucleophilic attack at the benzylic carbon atom of aromatic epoxides, such as styrene oxide, is observed. However, aliphatic unsymmetrical alkenyl oxides undergo selective nucleophilic attack at the sterically less hindered carbon atom. A variety of β-hydroxy sulfides were obtained in short reaction time and excellent yields with nearly complete regioselectivity  

    Cavity-mediated stationary atom-mirror entanglement in the presence of photothermal effects

    , Article Physics Letters, Section A: General, Atomic and Solid State Physics ; Volume 376, Issue 45 , 2012 , Pages 2955-2961 ; 03759601 (ISSN) Abdi, M ; Bahrampour, A. R ; Sharif University of Technology
    We study stationary entanglement properties of an optomechanical system containing an atomic ensemble. We focus onto the case of the movable mirror strongly coupled to the cavity field through both radiation pressure and photothermal force. Exploiting a quantum Langevin equation approach we investigate the bipartite entanglement properties of various bipartite subsystems as well as stationary tripartite entanglement of the system. We particularly study robustness of the atom-mirror entanglement against temperature. We show that, even though the photothermal force is a dissipative force, it can significantly improve the cavity mediated atom-mirror entanglement  

    Atomic interactions between metallic tips and surfaces in NC-AFM

    , Article Journal of Physics D: Applied Physics ; Volume 48, Issue 12 , February , 2015 ; 00223727 (ISSN) Pishkenari, H. N ; Sharif University of Technology
    Institute of Physics Publishing  2015
    In this paper, the atomic-scale interactions between metallic tips and samples in noncontact atomic force microscopy (NC-AFM) are studied using molecular dynamics simulations. The effects of the tip and sample materials, the surface plane direction and the lateral position of the tip with respect to the sample, on the interaction force and the dissipated energy, are investigated. The simulations conducted demonstrate that, generally, we can classify the possible outcomes for the dynamics due to the tip-surface interactions into four major categories. The first category includes all cases in which there are no considerable instabilities in tip-surface interactions, leading to negligible... 

    Analytical model based on cohesive energy to indicate the edge and corner effects on melting temperature of metallic nanoparticles

    , Article Chemical Physics ; Volume 378, Issue 1-3 , 2010 , Pages 14-18 ; 03010104 (ISSN) Shidpour, R ; Delavari H. H ; Vossoughi, M ; Sharif University of Technology
    An analytical model based on cohesive energy has been conducted to study the effects of edge, corner, and inward surface relaxation as varying parameters on melting temperature of nanoparticles. It is shown that taking into account the edge and corner (EC) atoms of nanoparticle, causes to drop melting temperature more, when compared to consider them the same as only surface atoms. This reduction is significant especially when the size of nanoparticle is below 10 nm. The results are supported by available experimental results of tin, lead and gold melting temperature (Tm). Finally, it is shown that inward relaxation increases melting temperature slightly  

    Investigation of the size-dependent dynamic characteristics of atomic force microscope microcantilevers based on the modified couple stress theory

    , Article International Journal of Engineering Science ; Volume 48, Issue 12 , 2010 , Pages 1985-1994 ; 00207225 (ISSN) Kahrobaiyan, M. H ; Asghari, M ; Rahaeifard, M ; Ahmadian, M. T ; Sharif University of Technology
    In this paper, the resonant frequency and sensitivity of atomic force microscope (AFM) microcantilevers are studied using the modified couple stress theory. The classical continuum mechanics is incapable of interpreting micro-structure-dependent size effects when the size of structures is in micron- and sub-micron scales. However, this dependency can be well treated by using non-classical continuum theories. The modified couple stress theory is a non-classic continuum theory which employs additional material parameters besides those appearing in classical continuum theory to treat the size-dependent behavior. In this work, writing differential equations of motion of AFM cantilevers together... 

    Quantum motion effects in an ultracold-atom mach-zehnder interferometer

    , Article Physical Review A - Atomic, Molecular, and Optical Physics ; Volume 78, Issue 1 , 2008 ; 10502947 (ISSN) Lizuain, I ; Mousavi, V ; Seidel, D ; Muga, J. G ; Sharif University of Technology
    We study the effect of quantum motion in a Mach-Zehnder interferometer where ultracold, two-level atoms cross a π2-π-π2 configuration of separated, laser illuminated regions. Explicit and exact expressions are obtained for transmission amplitudes of monochromatic, incident atomic waves using recurrence relations which take into account all possible paths: the direct ones usually considered in the simple semiclassical treatment, but including quantum motion corrections, and the paths in which the atoms are repeatedly reflected at the fields. © 2008 The American Physical Society  

    Seeking better times: Atomic clocks in the generalized Tonks-Girardeau regime

    , Article Journal of Physics: Conference Series ; Volume 99, Issue 1 , 2008 ; 17426588 (ISSN) Mousavi, S. V ; Del Campo, A ; Lizuain, I ; Pons, M ; Muga, J. G ; Sharif University of Technology
    Institute of Physics Publishing  2008
    First we discuss briefly the importance of time and time keeping, explaining the basic functioning of clocks in general and of atomic clocks based on Ramsey interferometry in particular. The usefulness of cold atoms is discussed, as well as their limits if Bose-Einstein condensates are used. We study as an alternative a different cold-atom regime: the Tonks-Girardeau (TG) gas of tightly confined and strongly interacting bosons. The TG gas is reviewed and then generalized for two-level atoms. Finally, we explore the combination of Ramsey interferometry and TG gases. © 2008 IOP Publishing Ltd  

    Clean and facile condensations reaction of indoles and carbonyl compounds under solvent-free conditions

    , Article Letters in Organic Chemistry ; Volume 3, Issue 2 , 2006 , Pages 161-164 ; 15701786 (ISSN) Mehrazma, S ; Azizi, N ; Saidi, M. R ; Sharif University of Technology
    A simple, rapid, atom economy and highly efficient green protocol has been developed for the reactions of indole with carbonyl compounds under solvent- free conditions. The attractive features of these procedures are the mild reaction conditions, high conversions, cleaner reaction profiles, inexpensive and environmentally friendly lithium perchlorate and short reaction times. © 2006 Bentham Science Publishers Ltd  

    Height fluctuations and intermittency of V2O5 films by atomic force microscopy

    , Article Journal of Physics Condensed Matter ; Volume 15, Issue 12 , 2003 , Pages 1889-1898 ; 09538984 (ISSN) Iraji Zad, A ; Kavei, G ; Rahimi Tabar, M. R ; Vaez Allaei, S. M ; Sharif University of Technology
    The spatial scaling law and intermittency of the V2O5 surface roughness has been investigated by atomic force microscopy. The intermittency of the height fluctuations has been checked by two different methods, first, by measuring the scaling exponent of the qth moment of height-difference fluctuations i.e. Cq = <|h(x1) - h(x2)|q>, and second, by defining the generating function Z(q, N) and generalized multi-fractal dimension Dq. These methods predict that there is no intermittency in the height fluctuations. The observed roughness and dynamical exponents can be explained by numerical simulation on the basis of the forced Kuramoto-Sivashinsky equation  

    Quantum secret sharing based on reusable Greenberger-Horne-Zeilinger states as secure carriers

    , Article Physical Review A - Atomic, Molecular, and Optical Physics ; Volume 67, Issue 4 , 2003 , Pages 443021-443024 ; 10502947 (ISSN) Bagherinezhad, S ; Karimipour, V ; Sharif University of Technology
    American Physical Society  2003
    A protocol for quantum secret sharing based on reusable entangled state was presented. In this protocol, a sequence of bits was transmitted to two parties so that they can recover half of the bits independently. The security of the protocol against eavesdropping and against cheating by one of the receivers was also discussed