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Introducing an effective method for extending the high harmonic spectrum plateau from gas targets
, Article Journal of Physics B: Atomic, Molecular and Optical Physics ; Volume 54, Issue 4 , February , 2021 ; 09534075 (ISSN) ; Monfared, M ; Majles Ara, M. H ; Sadighi Bonabi, R ; Sharif University of Technology
IOP Publishing Ltd
2021
Abstract
An effective semi-classical method is introduced for controlling the high-order harmonic generation process and extending the cutoff frequency. This method is capable of defining the proper specification of the driving laser for maximizing the cutoff frequency. This method is evaluated by examining the high harmonic spectrum from the hydrogen atom and the fluorine (F2) molecule irradiated by single-, two-, and three-color laser fields. This study is done using the time-dependent density functional theory in a three-dimensional space. The results show that the single-, two-, and three-color laser pulses tuned by proper specifications could extend the cutoff frequency by up to 85%, 176%, and...
Nano cobalt-copper ferrite catalyzed regioselective α-C(sp3)–H cyanation of amines: Secondary, tertiary, and drug molecules
, Article Catalysis Communications ; Volume 149 , 2021 ; 15667367 (ISSN) ; Pourkaveh, R ; Heidarian, M ; Sharif University of Technology
Elsevier B.V
2021
Abstract
Oxidative cyanation of sp3C–H bonds at the α position of amines was achieved using CoCuFe2O4 as a catalyst and NaCN as an inexpensive cyanide source at room temperature. CoCuFe2O4 was found to be an active catalyst for Csp [3]-Csp coupling, efficiently delivering valuable α-aminonitriles from tertiary/secondary amines in good yields. The corresponding products were obtained with high selectivity toward α position. In addition, functional group tolerance offered the opportunity for application in late-stage functionalization of biologically active molecules. This transformation proceeds convenient on a gram-scale, and the catalyst can be reused for several runs with consistent catalytic...
Graphic: Graph-based hierarchical clustering for single-molecule localization microscopy
, Article 18th IEEE International Symposium on Biomedical Imaging, ISBI 2021, 13 April 2021 through 16 April 2021 ; Volume 2021-April , 2021 , Pages 1892-1896 ; 19457928 (ISSN); 9781665412469 (ISBN) ; Aziznejad, S ; Unser, M ; Sage, D ; Sharif University of Technology
IEEE Computer Society
2021
Abstract
We propose a novel method for the clustering of point-cloud data that originate from single-molecule localization microscopy (SMLM). Our scheme has the ability to infer a hierarchical structure from the data. It takes a particular relevance when quantitatively analyzing the biological particles of interest at different scales. It assumes a prior neither on the shape of particles nor on the background noise. Our multiscale clustering pipeline is built upon graph theory. At each scale, we first construct a weighted graph that represents the SMLM data. Next, we find clusters using spectral clustering. We then use the output of this clustering algorithm to build the graph in the next scale; in...
All-Carbon negative differential resistance nanodevice using a single flake of nanoporous graphene
, Article ACS Applied Electronic Materials ; Volume 3, Issue 8 , 2021 , Pages 3418-3427 ; 26376113 (ISSN) ; Akhavan, O ; Shayesteh Zeraati, A ; Sattari Esfahlan, S. M ; Sharif University of Technology
American Chemical Society
2021
Abstract
A temperature-induced degenerate p-type graphene nanopore/reduced graphene oxide (GNP/rGO) heterojunction-based nanodevice was prepared and studied for the first time, showing a robust negative differential resistance (NDR) feature. In this regard, cellulose-based perforated graphene foams (PGFs), containing numerous nanopores (with an average size of ∼2 nm surrounded by nearly six-layer rGO walls) were synthesized using bagasse as a green starting material. The PGFs with an essential p-type semiconducting property showed a band gap energy of ∼1.8 eV. The observed two-terminal NDR peak could present stable and reversible features at high temperatures of 586-592 K. It was demonstrated that...
Acidity enhancement of α-carbon of beta diketones via hydroxyl substituents: A density functional theory study
, Article Journal of Physical Organic Chemistry ; Volume 34, Issue 3 , 2021 ; 08943230 (ISSN) ; Fattahi, A ; Sharif University of Technology
John Wiley and Sons Ltd
2021
Abstract
Density functional theory method and B3LYP/6-311++G(d,p) level of theory were used to determine the acidity of α-carbon in the hydroxyl derivatives of beta diketones in the gas phase. An investigation of acidity strength in the gas phase indicates that α-carbon of hydroxyl derivatives of beta diketones become stronger acids than the α-carbon of beta diketone itself as their conjugate bases gain more stability via both enolate and hydrogen bond formation. Natural bond orbital and quantum theory of atoms in molecules analyses also confirm the role of hydrogen bond interactions on increasing the acidity of α-carbon of hydroxyl derivatives of beta diketones. © 2020 John Wiley & Sons, Ltd
Low loaded MoS2/Carbon cloth as a highly efficient electrocatalyst for hydrogen evolution reaction
, Article International Journal of Hydrogen Energy ; 2021 ; 03603199 (ISSN) ; Mehdipour, H ; Moshfegh, A. Z ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Active edge sites of MoS2 nanosheets exhibit promising futures for hydrogen evolution reaction (HER), comparable with remarkable performances of highly cost platinum. However, 3D structures of MoS2 suffer from a lack of high mobility and unexposed active sites which lower the electrocatalytic activity. In this study, we show that there is a balance between increasing the active sites on the one hand and managing the charge transfer to facilitate the reaction on the other hand, and achieving this balance increases the efficiency of the electrocatalyst tremendously. For this purpose, we directly attached exfoliated MoS2 nanosheets onto carbon cloth (CC) substrate as a 3D network of conductive...
Structural and dynamical fingerprints of the anomalous dielectric properties of water under confinement
, Article Physical Review Materials ; Volume 5, Issue 2 , 2021 ; 24759953 (ISSN) ; Esfandiar, A ; Hassanali, A ; Ejtehadi, M. R ; Sharif University of Technology
American Physical Society
2021
Abstract
There is a long-standing question about the molecular configuration of interfacial water molecules in the proximity of solid surfaces, particularly carbon atoms, which plays a crucial role in electrochemistry and biology. In this study, the dielectric, structural, and dynamical properties of confined water placed between two parallel graphene walls at different interdistances from the angstrom scale to a few tens of nanometer have been investigated using molecular dynamics. For the dielectric properties of water, we show that the dielectric constant of the perpendicular component of water drastically decreases under sub-2-nm spatial confinement. The dielectric constant data obtained through...
Gold at crossroads of radical generation and scavenging at density functional theory level: Nitrogen and oxygen free radicals versus their precursors in the face of nanogold
, Article Journal of Physical Organic Chemistry ; Volume 34, Issue 1 , 2021 ; 08943230 (ISSN) ; Kassaee, M. Z ; Ayoubi Chianeh, M ; Fattahi, A ; Sharif University of Technology
John Wiley and Sons Ltd
2021
Abstract
In our previous report (J. Phys. Org. Chem., 2017), we discussed the dual behavior of gold nanocluster (Au3 NC), where it scavenged reactive oxygen species (ROS) while promoted their generation to a lesser extent. Continuing this quest, we investigate the effects of Au3 NC on common reactive nitrogen species (RNS: O=N˙ and O=N-O) and their precursors (O=N-H and O=N-O-H, respectively), at B3LYP/LACVP+* level of theory. We compare the results with those of prevalent ROS (H-O˙ and H-O-O˙) and their precursors (H-O-H and H-O-O-H, respectively). To this end, various parameters are probed such as binding energy (Eb), bond dissociation energy (BDE), bond lengths, Mullikan spin density (MSD),...
Structural and dynamical fingerprints of the anomalous dielectric properties of water under confinement
, Article Physical Review Materials ; Volume 5, Issue 2 , 2021 ; 24759953 (ISSN) ; Esfandiar, A ; Hassanali, A ; Ejtehadi, M. R ; Sharif University of Technology
American Physical Society
2021
Abstract
There is a long-standing question about the molecular configuration of interfacial water molecules in the proximity of solid surfaces, particularly carbon atoms, which plays a crucial role in electrochemistry and biology. In this study, the dielectric, structural, and dynamical properties of confined water placed between two parallel graphene walls at different interdistances from the angstrom scale to a few tens of nanometer have been investigated using molecular dynamics. For the dielectric properties of water, we show that the dielectric constant of the perpendicular component of water drastically decreases under sub-2-nm spatial confinement. The dielectric constant data obtained through...
Gold at crossroads of radical generation and scavenging at density functional theory level: Nitrogen and oxygen free radicals versus their precursors in the face of nanogold
, Article Journal of Physical Organic Chemistry ; Volume 34, Issue 1 , 2021 ; 08943230 (ISSN) ; Kassaee, M.Z ; Ayoubi-Chianeh, M ; Fattahi, A ; Sharif University of Technology
John Wiley and Sons Ltd
2021
Abstract
In our previous report (J. Phys. Org. Chem., 2017), we discussed the dual behavior of gold nanocluster (Au3 NC), where it scavenged reactive oxygen species (ROS) while promoted their generation to a lesser extent. Continuing this quest, we investigate the effects of Au3 NC on common reactive nitrogen species (RNS: O=N˙ and O=N-O) and their precursors (O=N-H and O=N-O-H, respectively), at B3LYP/LACVP+* level of theory. We compare the results with those of prevalent ROS (H-O˙ and H-O-O˙) and their precursors (H-O-H and H-O-O-H, respectively). To this end, various parameters are probed such as binding energy (Eb), bond dissociation energy (BDE), bond lengths, Mullikan spin density (MSD),...
Bacterial receiver prototype for molecular communication using rhamnose operon in a microfluidic environment
, Article IEEE Transactions on Nanobioscience ; Volume 20, Issue 4 , 2021 , Pages 426-435 ; 15361241 (ISSN) ; Mashhadian, A ; Farahnak Ghazani, M ; Arjmandi, H. R ; Alsadat Rad, M ; Shamloo, A ; Vosoughi, M ; Nasiri Kenari, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2021
Abstract
Bacterial populations are promising candidates for the development of the receiver and transmitter nanomachines for molecular communication (MC). A bacterial receiver is required to uptake the information molecules and produce the detectable molecules following a regulation mechanism. We have constructed a novel bacterial MC receiver using an inducible bacterial L-rhamnose-regulating operon. The proposed bacterial receiver produces green fluorescent protein (GFP) in response to the L-rhamnose information molecules following a quite fast regulation mechanism. To fabricate the receiver, the bacterial population has been transformed using a plasmid harboring L-rhamnose operon genes and gene...
Mechanical hydrolysis imparts self-destruction of water molecules under steric confinement
, Article Physical Chemistry Chemical Physics ; Volume 23, Issue 10 , 2021 , Pages 5999-6008 ; 14639076 (ISSN) ; Zakertabrizi, M ; Habibnejad Korayem, A ; Carbone, P ; Esfandiar, A ; Shahsavari, R ; Sharif University of Technology
Royal Society of Chemistry
2021
Abstract
Decoding behavioral aspects associated with the water molecules in confined spaces such as an interlayer space of two-dimensional nanosheets is key for the fundamental understanding of water-matter interactions and identifying unexpected phenomena of water molecules in chemistry and physics. Although numerous studies have been conducted on the behavior of water molecules in confined spaces, their reach stops at the properties of the planar ice-like formation, where van der Waals interactions are the predominant interactions and many questions on the confined space such as the possibility of electron exchange and excitation state remain unsettled. We used density functional theory and...
Comparison among various configurations of hybrid distillation–membrane setups for the energy efficiency improvement of bioethanol distillery: a simulation study
, Article Journal of Chemical Technology and Biotechnology ; October , 2021 ; 02682575 (ISSN) ; Aslam, Z ; Ali, U ; Akhtar, A ; Sharif University of Technology
John Wiley and Sons Ltd
2021
Abstract
BACKGROUND: Hybrid distillation–membrane setups have attracted attention in recent years due to their lower energy usage for ethanol purification. Membrane separation processes operate without heating that reduces energy demand. However, it is somewhat challenging to select the optimal material and process for a membrane purifying ethanol, especially to get an ethanol purity of 99.99% with maximum recovery. RESULTS: In this study, three different configurations of hybrid distillation–membrane setups are proposed consisting of distillation–pervaporation/vapor permeation processes by considering ceramic, polymeric and composite membranes. The design of hybrid processes is performed by coupling...
Lattice relaxation in many-electron states of the diamond vacancy
, Article Physical Review B - Condensed Matter and Materials Physics ; Volume 71, Issue 3 , 2005 ; 10980121 (ISSN) ; Vesaghi, M. A ; Esfarjani, K ; Ghods Elahi, T ; Sayari, M ; Hashemi, H ; Gorjizadeh, N ; Sharif University of Technology
2005
Abstract
Symmetric lattice relaxation around a vacancy in diamond and its effect on many electron states of the defect have been investigated. A molecular approach is used to evaluate accurately electron-electron (e-e) interaction via a semiempirical formalism which is based on a generalized Hubbard Hamiltonian. Coupling of the defect molecule to surrounding bulk is also considered using an improved Stillinger-Weber potential for diamond. Strong dependence of the electronic energy levels to the relaxation size of the nearest neighbor (NN) atoms indicates that in order to obtain quantitative results the effect of lattice relaxation should be considered. Except for the high spin state of the defect 5A...
Electrocatalytic oxidation of methanol on a nickel electrode modified by nickel dimethylglyoxime complex in alkaline medium
, Article Journal of Power Sources ; Volume 144, Issue 1 , 2005 , Pages 21-27 ; 03787753 (ISSN) ; Shahrokhian, S ; Asgari, M ; Ghannadi Maragheh, M ; Irannejad, L ; Khanchi, A ; Sharif University of Technology
2005
Abstract
Electrocatalytic oxidation of methanol on a nickel disc electrode coated with nickel dimethyglyoxime complex (NiDMG), conditioned by potential recycling in a potential range of 100-700 mV (versus SCE) is studied by cyclic voltammetry in alkaline medium (0.10 M NaOH). The results show that the NiODMG layer formed at the surface of electrode behaves as an efficient electrocatalyst for the oxidation of methanol in alkaline medium via Ni(III) species with the cross exchange reaction occurring through out the layer at a low concentration of methanol. A plausible mechanism was proposed for catalytic oxidation of methanol at this modified electrode. Moreover, the effects of various parameters such...
Design and Simulation of CMOS Based Magnetic Sensor for Biosensing Applications
, M.Sc. Thesis Sharif University of Technology ; Akbari, Mahmood (Supervisor) ; Fotowat-Ahmady, Ali (Supervisor)
Abstract
This paper presents a scalable and ultrasensitive magnetic biosensing scheme based on on-chip LC resonance frequency-shifting. The sensor transducer gain is demonstrated as being location-dependent on the sensing surface and proportional to the local polarization magnetic field strength |B|2 generated by the sensing inductor. To improve the gain uniformity, a periodic coil is proposed as a substitution for the standard process coil. As an implementation example, the circuit is designed in a 65nm CMOS process. The spatially uniform sensor gain of the array is verified by COMSOL simulations. Overall, the presented sensor demonstrates an improvement in the uniformity of the inductor’s magnetic...
Inhibition effect of 3,5 bis (2-pyridil) 4-amino 1,2,4 triazole and 1-10 phenantrolin on corrosion of mild steel in acid solutions
, Article British Corrosion Journal ; Volume 37, Issue 1 , 2002 , Pages 76-80 ; 00070599 (ISSN) ; Hosseini, M. G ; Ghorbani, M ; Sharif University of Technology
IOM Communications Ltd
2002
Abstract
The inhibition effects of 3.5 bis (2-pyridil) 4-amino 1,2,4 triazole (NBTA) and 1-10 phenantrolin (PHEN), on corrosion of mild steel in acid solutions, (sulphuric acid and hydrochloric acid) were studied. The Tafel polarisation and ac impedance techniques were employed. Results obtained reveal that both compounds are relatively good inhibitors. The inhibition efficiencies of NBTA are higher in hydrochloric acid than in sulphuric acid. This has been attributed to the synergistic effect of chloride ions present in hydrochloric acid. The mechanism of inhibition of PHEN is believed to be owing to the formation of insoluble chelates between the organic molecules and atom/ion on the metal surface....
Modeling Two-Dimensional Face from DNA Using the Face Embedding Approach in Deep Learning
, M.Sc. Thesis Sharif University of Technology ; Hossein Khalaj, Babak (Supervisor)
Abstract
the purpose of this research is to construct the facial image of a person from corresponding DNA. In this problem, we have a set of DNAs and facial images and we want to find the relation between the DNA and the features of facial images.using this relation we can find the facial Image of a person using the DNA. for this purpose we should first extract the features of faces that have the most variation among the population. by studying the feature extraction methods in this field, we borrow the deep neural network method that is used in face recognition fields.we found significant relations between DNA and extracted features from this network. finally using this relation we can predict the...
N-Type conductive small molecule assisted 23.5% efficient inverted perovskite solar cells
, Article Advanced Energy Materials ; Volume 12, Issue 34 , 2022 ; 16146832 (ISSN) ; Li, Y ; Zhang, Y ; Zhao, J ; Wang, T ; Yang, B ; Pu, X ; Yang, J ; Chen, H ; Chen, X ; Li, X ; Ghasemi, S ; Salari, H ; Hagfeldt, A ; Li, X ; Sharif University of Technology
John Wiley and Sons Inc
2022
Abstract
Because of the compatibility with tandem devices and the ability to be manufactured at low temperatures, inverted perovskite solar cells have generated far-ranging interest for potential commercial applications. However, their efficiency remains inadequate owing to various traps in the perovskite film and the restricted hole blocking ability of the electron transport layer. Thus, in this work, a wide-bandgap n-type semiconductor, 4,6-bis(3,5-di(pyridin-4-yl)phenyl)-2-phenylpyrimidine (B4PyPPM), to modify a perovskite film via an anti-solvent method is introduced. The nitrogen sites of pyrimidine and pyridine rings in B4PyPPM exhibit strong interactions with the undercoordinated lead ions in...
Structural and theoretical exploring of noncovalent interactions in Chlorido- and Nitrito-rhenium(I) tricarbonyl complexes bearing 2,3-Butadiene-bis(2-nitrobenzylidene)hydrazine Ligand: Intramolecular Re–κ1-endo-ONO(lone pair)…π*(C[tbnd]O) interaction
, Article Inorganica Chimica Acta ; Volume 540 , 2022 ; 00201693 (ISSN) ; Heshmatnia, F ; Sharif University of Technology
Elsevier B.V
2022
Abstract
Herein, we report the synthesis, characterization and combined structural and full computational analysis of noncovalent interactions in a new hydrazine ligand and its two chlorido- and endo-nitrito-rhenium(I) tricarbonyl complexes. The analysis of crystal structures has been accompanied by comprehensive computational studies of the noncovalent interactions utilizing the quantum theory of atoms in molecules (QTAIM), natural bond orbitals (NBO), independent gradient model (IGM), and electron localization function (ELF) to shed light on the nature of the interactions. On the other hand, comprehensive energy decomposition analysis (EDA) by extended transition state coupled with natural orbitals...