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A thermodynamically-consistent large deformation theory coupling photochemical reaction and electrochemistry for light-responsive gels
, Article Journal of the Mechanics and Physics of Solids ; Volume 116 , July , 2018 , Pages 239-266 ; 00225096 (ISSN) ; Zhang, H ; Naghdabadi, R ; Hu, Y ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
Gels are composed of crosslinked polymer network and solvent molecules. When the main chain network is incorporated with functional groups that can undergo photo-chemical reaction upon light irradiation, the gel becomes light-responsive. Under irradiation, the photosensitive groups may undergo photo-ionization process and generate charges that are attached to the main chain or diffuse into the solvent. The newly generated ions disturb the osmotic balance of the gel medium. As a result, water molecules and mobile ions are driven into or out of the network to compensate the osmotic imbalance, which eventually leads to macroscopic swelling or shrinking of the gel. In this work, we develop a...
Controlling the multi-electron dynamics in the high harmonic spectrum from N2O molecule using TDDFT
, Article Journal of Chemical Physics ; Volume 148, Issue 23 , 2018 ; 00219606 (ISSN) ; Irani, E ; Sadighi Bonabi, R ; Sharif University of Technology
American Institute of Physics Inc
2018
Abstract
In this study, high harmonic generation from a multi-atomic nitrous oxide molecule was investigated. A comprehensive three-dimensional calculation of the molecular dynamics and electron trajectories through an accurate time-dependent density functional theory was conducted to efficiently explore a broad harmonic plateau. The effects of multi-electron and inner orbitals on the harmonic spectrum and generated coherent attosecond pulses were analyzed. The role of the valence electrons in controlling the process and extending the harmonic plateau was investigated. The main issue of producing a super-continuum harmonic spectrum via a frequency shift was considered. The time-frequency...
An adaptive pulse-width modulation for limited molecule production and storage
, Article 2018 Iran Workshop on Communication and Information Theory, IWCIT 2018, 25 April 2018 through 26 April 2018 ; 2018 , Pages 1-6 ; 9781538641491 (ISBN) ; Mirmohseni, M ; Nasiri Kenari, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
The nature of molecular transmitter imposes some limitations on the molecule production process and its storage. As these molecules act the role of the information carriers, their limitation affect the transmission process and the system performance considerably. In this paper, we focus on these limitations at the transmitter, the limited production rate and finite storage capacity. We consider a time-slotted communication where the transmitter opens its outlet and releases the stored molecules for a time duration to send bit '1' and remains silent to send bit '0'. By changing the duration molecules are released, we propose an adaptive pulse-width modulation. The objective is to find the...
Generation of two-soliton and three-soliton molecules in a circular fiber array laser
, Article Laser Physics ; Volume 28, Issue 4 , March , 2018 ; 1054660X (ISSN) ; Rooholamininejad, H ; Bahrampour, A ; Sharif University of Technology
Institute of Physics Publishing
2018
Abstract
In this work, the generation of two-soliton and three-soliton molecules in a circular fiber array laser with an active optical central fiber is studied. Certain fibers of the array are excited by Gaussian and super-Gaussian pulses. The central fiber of the circular fiber laser is a rare-earth doped fiber. A circular fiber array is employed as a saturable absorber in a soliton mode locked fiber laser. Generation of two-soliton and three-soliton molecules are observed in our simulation. Numerical calculation of binding energy shows that the super-Gaussian pulse tends to be more stable, and therefore it would be a proper choice for the generation of soliton molecules in the circular fiber array...
Ionic liquid based on 6-amino-6-deoxy hexopyranose cation and BF4 ¯, PF6 ¯, and ClO4 ¯ as anions: a DFT study on the structural and electronic properties
, Article Journal of Physical Organic Chemistry ; Volume 31, Issue 5 , 2018 ; 08943230 (ISSN) ; Fattahi, A ; Sharif University of Technology
John Wiley and Sons Ltd
2018
Abstract
In this study, the structural and electronic properties of a carbohydrate-based (6-amino-6-deoxy hexopyranose [ADHP]) ionic liquid were explored. The interactions among 3 anions (BF4 ¯, PF6 ¯, and ClO4 ¯) and ADHP as cation were investigated at B3LYP/6-311++G(d,p) level. Based on the calculated interaction energy, it was found that PF6 ¯ anion has the highest interaction energy with ADHP. It was found that the hydrogen bonds play an important role in the interaction of ion pairs. The nature of hydrogen bonds in the optimized ion pars was analyzed by using natural bond orbital analysis and the quantum theory of atoms in molecules. The linear relationship between electron density at the bond...
Molecular dynamics simulations of orai reveal how the third transmembrane segment contributes to hydration and ca2+ selectivity in calcium release-activated calcium channels
, Article Journal of Physical Chemistry B ; Volume 122, Issue 16 , 2018 , Pages 4407-4417 ; 15206106 (ISSN) ; Berti, C ; Ejtehadi, M. R ; Furini, S ; Sharif University of Technology
American Chemical Society
2018
Abstract
Calcium release-activated calcium (CRAC) channels open upon depletion of Ca2+ from the endoplasmic reticulum, and when open, they are permeable to a selective flux of calcium ions. The atomic structure of Orai, the pore domain of CRAC channels, from Drosophila melanogaster has revealed many details about conduction and selectivity in this family of ion channels. However, it is still unclear how residues on the third transmembrane helix can affect the conduction properties of the channel. Here, molecular dynamics and Brownian dynamics simulations were employed to analyze how a conserved glutamate residue on the third transmembrane helix (E262) contributes to selectivity. The comparison...
The control of electron quantum trajectories on the high-order harmonic generation of CO and N2 molecules in the presence of a low frequency field
, Article Journal of Chemical Physics ; Volume 148, Issue 14 , 2018 ; 00219606 (ISSN) ; Sadighi Bonabi, R ; Mohsen Nia, M ; Irani, E ; Sharif University of Technology
American Institute of Physics Inc
2018
Abstract
In the present work, an efficient method is theoretically investigated for extending high-order harmonics and ultrashort attosecond pulse generation in N2 and CO molecules by using the time-dependent density functional theory approach. Our results show that by utilizing chirped laser field in the presence of a low frequency field, not only is the harmonic cutoff extended remarkably but also the single short quantum trajectory is selected to contribute to the harmonic spectra. When a low frequency field is added to the two-color chirped laser field, the long quantum trajectories are suppressed and only the short quantum trajectories contribute to the higher harmonic emission mechanism. As a...
Does gold cluster promote or scavenge radicals? A controversy at DFT
, Article Journal of Physical Organic Chemistry ; Volume 31, Issue 3 , 2018 ; 08943230 (ISSN) ; Kassaee, M. Z ; Fattahi, A ; Sharif University of Technology
John Wiley and Sons Ltd
2018
Abstract
Anticancer character of gold cluster has been indicated through its free radical scavenging properties. This is in contrast to its free radical promoting ability suggested by other workers. Here, we address this controversy by probing the stabilizing effects of Au3 cluster on RO• vs its impacts on RO–H bond dissociation enthalpy, at B3LYP/ LACVP+* level (R═H, methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, and phenyl). In the presence of Au3 cluster, bond dissociation enthalpy of O–H bond and the spin density at the RO• oxygen are reduced dramatically. These are clear evidences for both the Au3 facilitation of the RO–H bond breakage and its scavenging of RO• radical. Since O–Au...
Effects of physicochemical characteristics of magnetically recoverable biocatalysts upon fatty acid methyl esters synthesis from oils
, Article Renewable Energy ; Volume 116 , 2018 , Pages 613-622 ; 09601481 (ISSN) ; Kazemeini, M ; Singh, G ; Arpanaei, A ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
This study reports the importance of physicochemical characteristics of the core-shell structured polymer-coated Fe3O4 cluster@SiO2 nanocomposite particles for designing the biocatalysts used for transesterification of soybean oil. To demonstrate this issue, two different types of polymer molecules such as polyethylenimine (PEI) and polyacrylic acid (PAA) each with two different molecular weights are employed. The highest fatty acid methyl esters (FAMEs) synthesis yield values are achieved by the lipases immobilized onto the low- and high-molecular-weight PEI-coated particles as compared to those of the low- and high-molecular-weight PAA-coated particles (i.e., ∼64.8% and ∼73.1% versus...
Grand canonical Monte Carlo and molecular dynamics simulations of the structural properties, diffusion and adsorption of hydrogen molecules through poly(benzimidazoles)/nanoparticle oxides composites
, Article International Journal of Hydrogen Energy ; Volume 43, Issue 5 , 2018 , Pages 2803-2816 ; 03603199 (ISSN) ; Dehghani, M ; Pazirofteh, M ; Asghari, M ; Mohammadi, A. H ; Shahsavari, D ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
Comprehensive structural/molecular simulations have been undertaken to study the poly(benzimidazoles) (PBI) membrane combined with four different nano-oxide materials (ZnO, Al2O3, SiO2 and TiO2) for purification and production of hydrogen from natural gases. Composite membranes were built with different amounts of nano-oxide materials to investigate the influence of nano-oxide content on the PBI membrane performance. Several structural characterizations such as FFV, WAXD and also a thermal one (glass transition temperature) were done to study the structural properties of all simulated membrane cells. Moreover, MSD and adsorption isotherms tasks were used to estimate the diffusivity and...
Delivery of hydrophobic anticancer drugs by hydrophobically modified alginate based magnetic nanocarrier
, Article Industrial and Engineering Chemistry Research ; Volume 57, Issue 3 , 2018 , Pages 822-832 ; 08885885 (ISSN) ; Amin, S. S ; Hosseini, H ; Sharif University of Technology
American Chemical Society
2018
Abstract
Since most of the anticancer drugs have low solubility in water, the clinical use of them is limited unless by some modification the solubility increases or the drug is carried with a soluble compartment. To solve this problem, we prepared a magnetic nanocarrier with a hydrophobic surface based on oleic acid chains in which hydrophobic drug molecules such as doxorubicin hydrochloride (DOX) and paclitaxel (PTX) are easily adsorbed onto the surface. Since the drug molecules are physically adsorbed on the surface, large amounts of DOX (282 mg·g-1) and PTX (316 mg·g-1) were immobilized onto the nanocarrier. Then, the surface of the drug loaded magnetic core was covered by a smart pH-sensitive...
Type-based sign modulation and its application for isi mitigation in molecular communication
, Article IEEE Transactions on Communications ; Volume 66, Issue 1 , 2018 , Pages 180-193 ; 00906778 (ISSN) ; Gohari, A ; Mirmohseni, M ; Nasiri Kenari, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
While ISI is a common issue in classical communications, it is more challenging and prominent in the context of molecular communication, because one cannot readily combat ISI with classical channel equalization techniques. This is due to the fact that transmitter can only release a positive amount of concentration of a specific molecule into the medium. Previous works have proposed use of chemical reactions to remove molecules from the environment, and to effectively simulate negative signals. However, the differential equation describing a diffusion-reaction process is non-linear. This precludes the possibility of using Fourier transform tools. In this paper, a solution for simulating...
Electrokinetic properties of asphaltene colloidal particles: determining the electric charge using micro electrophoresis technique
, Article Colloids and Surfaces A: Physicochemical and Engineering Aspects ; Volume 541 , 2018 , Pages 68-77 ; 09277757 (ISSN) ; Abolghasemi, E ; Hosseini, A ; Ayatollahi, S ; Dehghani, F ; Sharif University of Technology
Elsevier B.V
2018
Abstract
In this work, the electrokinetic properties of asphaltene particles have been investigated. Micro-electrophoresis method by applying DC electric field, was utilized to different mixtures containing asphaltene to determine its electric charge. It was observed that in the case of using n-heptane and its mixture with toluene (heptol), the asphaltene particles were showed to be positively charged however for toluene itself, they expressed no tendency toward the electrodes. While it is expected that larger asphaltene aggregates carry higher electric charge, the results contradictorily showed that they are mainly governed by gravity rather than electro-static force and that “aggregation” reduces...
Reactions of doubly deprotonated 2,6-naphthalenedicarboxylic acid with alcohols: Proton transfer versus solvation
, Article International Journal of Mass Spectrometry ; Volume 418 , 2017 , Pages 180-187 ; 13873806 (ISSN) ; Meyer, M. M ; O'Hair, R. A. J ; Fattahi, A ; Schmidt, J ; Kass, S. R ; Sharif University of Technology
Elsevier B.V
2017
Abstract
Electrospray ionization of 2,6-naphthalenedicarboxylic acid readily affords its doubly deprotonated dicarboxylate dianion (12−). This species clusters with background water and added alcohols in an ion trap at ∼10−3 Torr. Sequential solvation is observed to afford mono and dicoordinated ions. Surprisingly, the latter cluster (12−• 2TFE) is protonated by 2,2,2-trifluoroethanol (TFE) whereas 12−and 12−• TFE are not even though ΔH°acid(TFE) = 361.7 ± 2.5 kcal mol−1 (as given in the NIST website at http://webbook.nist.gov) and the B3LYP/6-31+G(d,p) proton affinities are 384.7 (12−), 377.6 (12−• TFE), and 362.7 (12−• 2TFE) kcal mol−1. That is, only the weakest base in this series, and the dianion...
The ITO-capped WO3 nanowires biosensor based on field-effect transistor in label-free protein sensing
, Article Applied Physics A: Materials Science and Processing ; Volume 123, Issue 5 , 2017 ; 09478396 (ISSN) ; Sharif University of Technology
Springer Verlag
2017
Abstract
The fabrication of ITO-capped WO3 nanowires associated with their bio-sensing properties in field-effect transistor diagnostics basis as a biosensor has been reported. The bio-sensing property for manipulated nanowires elucidated that the grown nanostructures were very sensitive to protein. The ITO-capped WO3 nanowires biosensor showed an intensive bio-sensing activity against reliable protein. Polylysine strongly charged bio-molecule was applied as model system to demonstrate the implementation of materialized biosensor. The employed sensing mechanism was ‘label-free’ and depended on bio-molecule’s intrinsic charge. For nanowires synthesis, the vapor–liquid–solid mechanism was used....
Dielectric properties of nematic liquid crystal doped with Fe3O4 nanoparticles
, Article Phase Transitions ; Volume 90, Issue 4 , 2017 , Pages 371-379 ; 01411594 (ISSN) ; Majles Ara, M. H ; Saboohi, F ; Sharif University of Technology
Taylor and Francis Ltd
2017
Abstract
The influence of Fe3O4 nanoparticles (NPs) on dielectric properties of planar and homeotropic oriented nematic liquid crystals (NLCs) were studied during the temperature interval of 298–322 °K. It was found that the dielectric permittivity was considerably increased by adding NPs mass percentages. The structural characterization of the synthesized NPs with the scale 14–18 nm has been analyzed by the X-ray diffraction and field-emission scanning electron microscopy results. The obtained dielectric anisotropy (Δε) and mean dielectric (Formula presented.) have shown an immense increment in the value of 1% and 10% wt. NPs doped NLCs, respectively. These results were assigned to the strong...
Selective photo-dissociative ionization of methane molecule with TDDFT study
, Article Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy ; Volume 171 , 2017 , Pages 325-329 ; 13861425 (ISSN) ; Anvari, A ; Sadighi Bonabi, R ; Sharif University of Technology
Elsevier B.V
2017
Abstract
Three dimensional calculation of control dynamics for finding the optimized laser filed is formulated using an iterative method and time-dependent density functional approach. An appropriate laser pulse is designed to control the desired products in the dissociation of methane molecule. The tailored laser pulse profile, eigenstate distributions and evolution of the efficient occupation numbers are predicted and exact energy levels of this five-atomic molecule is obtained. Dissociation rates of up to 78%, 80%, 90%, and 82% for CH2 +, CH+, C+ and C++ are achieved. Based on the present approach one can reduce the controlling costs. © 2016 Elsevier B.V
On the design of graphene oxide nanosheets membranes for water desalination
, Article Desalination ; Volume 422 , 2017 , Pages 83-90 ; 00119164 (ISSN) ; Tavakoli, R ; Sharif University of Technology
Elsevier B.V
2017
Abstract
According to current researches, graphene oxide (GO) membranes show promising desalination properties due to ease of synthesis, low production cost, and high efficiency. There are several experimental works to study ionic sieving properties of GO membranes. However, it is difficult to characterize atomistic mechanism of water permeation and ion rejection by experimental approaches. On the other hand, there exist a few reports in which the atomistic picture of water permeation across GO membranes is investigated by means of molecular dynamics (MD) simulation. In the present work, in addition to water desalination, the atomic scale mechanism of ion rejection is studied using large scale MD...
Does gold cluster promote or scavenge radicals? A controversy at DFT
, Article Journal of Physical Organic Chemistry ; 2017 ; 08943230 (ISSN) ; Kassaee, M. Z ; Fattahi, A ; Sharif University of Technology
John Wiley and Sons Ltd
2017
Abstract
Anticancer character of gold cluster has been indicated through its free radical scavenging properties. This is in contrast to its free radical promoting ability suggested by other workers. Here, we address this controversy by probing the stabilizing effects of Au3 cluster on RO• vs its impacts on RO-H bond dissociation enthalpy, at B3LYP/ LACVP+* level (RH, methyl, ethyl, n-propyl, i-propyl, n-butyl, t-butyl, and phenyl). In the presence of Au3 cluster, bond dissociation enthalpy of O-H bond and the spin density at the RO• oxygen are reduced dramatically. These are clear evidences for both the Au3 facilitation of the RO-H bond breakage and its scavenging of RO• radical. Since O-Au anchoring...
A modified thermodynamic modeling of wax precipitation in crude oil based on PC-SAFT model
, Article Fluid Phase Equilibria ; Volume 429 , 2016 , Pages 313-324 ; 03783812 (ISSN) ; Ghotbi, C ; Jafari Behbahani, T ; Sharif University of Technology
Elsevier
2016
Abstract
Wax precipitation may occur in production or transportation of crude oil form field which is a serious problem in petroleum industry. Flow assurance issues concerning wax precipitation make it necessary to develop a precise thermodynamic model to predict the wax appearance temperature and amount of precipitation at different conditions. In this work a new procedure has been proposed to characterize crude oil based on the SARA test considering the wax and asphaltene as single pseudo components. Two scenarios have been investigated for the survey of the crude oil characterization, with and without asphaltene pseudo component. Also, in this work, the Perturbed Chain form of the Statistical...