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Seedless growth of two-dimensional disc-shaped WS2 layers by chemical vapor deposition
, Article Materials Chemistry and Physics ; Volume 257 , 2021 ; 02540584 (ISSN) ; Ghanbari, H ; Simchi, A ; Maghsoumi, A ; Sharif University of Technology
Elsevier Ltd
2021
Abstract
Chemical processing of two-dimensional (2D) transition metal dichalcogenides has attracted immense attention due to their unique optical, electrical, and catalytic properties. In this paper, we show that under special conditions during seedless chemical vapor deposition (CVD), it is possible to grow large-area 2D WS2 layers with disc-shaped morphology, which has been scarcely reported. Detailed characterizations of the CVD-grown layers by Raman spectroscopy, atomic force microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy have revealed that a gradient in the precursor concentration in the gas phase and strain energy in the deposited hexagonal clusters favor...
Synthesize and Characterization of 2D WS2 Nano-layers for Next Generation Optoelectronic Devices
, M.Sc. Thesis Sharif University of Technology ; Simchi, Abdolreza (Supervisor)
Abstract
Transition Metal Dichalcogenids (TMD) are types of 2D materials that exibit wide range of electronic, optical, mechanical, chemical, and thermal properties. These materials with MX2 general formula, have atract attentions with respect to their unusual properties because of their very limited dimensions. Their tunable properties and materials availibility make them attractive for wide range of applications. In recent years, chemical vapor deposition (CVD) methods are promising in preparing high quality TMD with scalable size, controllable thickness, and very excellent electronic properties. Also, chalenges are remaining in synthesis and transfering of TMD are difficulty for most of...
Developing seedless growth of atomically thin semiconductor layers: Application to transition metal dichalcogenides
, Article Ceramics International ; Volume 44, Issue 13 , 2018 , Pages 15795-15803 ; 02728842 (ISSN) ; Sovizi, S ; Ghanbari, H ; Simchi, A ; Aboudzadeh, N ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
Controlled growth of atomic monolayers of IV-VII transition metal dichalcogenides (TMDs) has provided unprecedented opportunities to fabricate modern optoelectronic nanodevices. However, synthesis of large-area and high quality two-dimensional TMDs is still challenging. We have synthesized WS2 and MoS2 nanosheets by atmospheric pressure chemical vapor deposition (APCVD) at wide-range of processing conditions. The nanostructures were analyzed by optical and confocal microscopy, atomic force microscopy, Raman spectroscopy, and X-ray diffraction to determine the thickness, lateral size and structure of the deposits. Through designing and performing of a set of controlled experiments as well as...
Plasma Processing and Treatment of 2D Transition Metal Dichalcogenides: Tuning Properties and Defect Engineering
, Article Chemical Reviews ; Volume 123, Issue 24 , 2023 , Pages 13869-13951 ; 00092665 (ISSN) ; Angizi, S ; Ahmad Alem, A ; Goodarzi, R ; Rahmani Taji Boyuk, M. R ; Ghanbari, H ; Szoszkiewicz, R ; Simchi, A ; Kruse, P ; Sharif University of Technology
American Chemical Society
2023
Abstract
Two-dimensional transition metal dichalcogenides (TMDs) offer fascinating opportunities for fundamental nanoscale science and various technological applications. They are a promising platform for next generation optoelectronics and energy harvesting devices due to their exceptional characteristics at the nanoscale, such as tunable bandgap and strong light-matter interactions. The performance of TMD-based devices is mainly governed by the structure, composition, size, defects, and the state of their interfaces. Many properties of TMDs are influenced by the method of synthesis so numerous studies have focused on processing high-quality TMDs with controlled physicochemical properties....
Physicomechanical properties of spark plasma sintered carbon nanotube-containing ceramic matrix nanocomposites
, Article Nanoscale ; Volume 9, Issue 35 , 2017 , Pages 12779-12820 ; 20403364 (ISSN) ; Sovizi, S ; Azarniya, A ; Rahmani Taji Boyuk, M. R ; Varol, T ; Nithyadharseni, P ; Madaah Hosseini, H. R ; Ramakrishna, S ; Reddy, M. V ; Sharif University of Technology
2017
Abstract
Recently, a wide variety of research works have focused on carbon nanotube (CNT)-ceramic matrix nanocomposites. In many cases, these novel materials are produced through conventional powder metallurgy methods including hot pressing, conventional sintering, and hot isostatic pressing. However, spark plasma sintering (SPS) as a novel and efficient consolidation technique is exploited for the full densification of high-temperature ceramic systems. In these binary nanocomposites, CNTs are added to ceramic matrices to noticeably modify their inferior properties and SPS is employed to produce fully dense compacts. In this review, a broad overview of these systems is provided and the potential...
Temperature-responsive smart nanocarriers for delivery of therapeutic agents: applications and recent advances
, Article ACS Applied Materials and Interfaces ; Volume 8, Issue 33 , 2016 , Pages 21107-21133 ; 19448244 (ISSN) ; Sahandi Zangabad, P ; Ghasemi, A ; Amiri, M ; Bahrami, M ; Malekzad, H ; Ghahramanzadeh Asl, H ; Mahdieh, Z ; Bozorgomid, M ; Ghasemi, A ; Rahmani Taji Boyuk, M. R ; Hamblin, M. R ; Sharif University of Technology
American Chemical Society
2016
Abstract
Smart drug delivery systems (DDSs) have attracted the attention of many scientists, as carriers that can be stimulated by changes in environmental parameters such as temperature, pH, light, electromagnetic fields, mechanical forces, etc. These smart nanocarriers can release their cargo on demand when their target is reached and the stimulus is applied. Using the techniques of nanotechnology, these nanocarriers can be tailored to be target-specific, and exhibit delayed or controlled release of drugs. Temperature-responsive nanocarriers are one of most important groups of smart nanoparticles (NPs) that have been investigated during the past decades. Temperature can either act as an external...
Experimental investigation of operating conditions for preparation of PVA-PEG blend membranes using supercritical CO2
, Article Journal of Supercritical Fluids ; Vol. 95 , November , 2014 , pp. 603-609 ; ISSN: 08968446 ; Nejad-Sadeghi, M ; Goodarznia, I ; Sharif University of Technology
2014
Abstract
Poly(vinyl alcohol)-polyethylene glycol, PVA-PEG, blended membrane were prepared using supercritical fluid assisted phase-inversion method, in which scCO2 was used as the anti-solvent. Poly(vinyl alcohol) was utilized as the main polymer, polyethylene glycol as the additive, and dimethyl sulfoxide (DMSO) as the solvent of these polymers. Taguchi method was used to investigate the effect of some operating parameters on the morphology of the membranes. The L16 orthogonal array was selected under the following conditions: pressure (100, 135, 165 and 200 bar), temperature (40, 45, 50 and 55°C) and PEG weight percent (0, 0.33, 0.66, and 1%). Total polymer concentration of solutions in all...
To Make the Membrane for Drug Retard Release by Supercritical System
, M.Sc. Thesis Sharif University of Technology ; Goodarznia, Iraj (Supervisor)
Abstract
In this study the main goal is to prepare a membrane to perform delayed drug release and absorbtion in the human body. To do so the supercritical method was used. A well-known biodegradable polymer was used. These kinds of polymers are used in drug delivery, wound dressing or scaffolding for cell culture. A membrane produced out of these kin of polymers is expected to have a good accordance with the goals.Ploy Vinyl alcohol, having very good bio degradable characteristics was used as the main polymer and Poly Ethylene Glycol (PEG) was used as an additive to make changes in the membrane structure. Also Dimethyl Sulfoxide, a polar solvent having the capability of solving both polymers is used....
Discovering associations among technologies using neural networks for tech-mining
, Article IEEE Transactions on Engineering Management ; 2020 ; Veisi, H ; Fateh rad, M ; Rahmani, R ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2020
Abstract
In both public and private sectors, critical technology-based tasks, such as innovation, forecasting, and road-mapping, are faced with unmanageable complexity due to the ever-expanding web of technologies which can range into thousands. This context cannot be easily handled manually or with efficient speed. However, more precise and insightful answers are expected. These answers are the fundamental challenge addressed by tech-mining. For tech-mining, discovering the associations among them is a critical task. These associations are used to form a weighted directed graph of technologies called “association tech-graph” which is used for technology development, trend analysis, policymaking,...
Discovering associations among technologies using neural networks for tech-mining
, Article IEEE Transactions on Engineering Management ; Volume 69, Issue 4 , 2022 , Pages 1394-1404 ; 00189391 (ISSN) ; Veisi, H ; Fateh-Rad, M ; Rahmani, R ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2022
Abstract
In both public and private sectors, critical technology-based tasks, such as innovation, forecasting, and road-mapping, are faced with unmanageable complexity due to the ever-expanding web of technologies which can range into thousands. This context cannot be easily handled manually or with efficient speed. However, more precise and insightful answers are expected. These answers are the fundamental challenge addressed by tech-mining. For tech-mining, discovering the associations among them is a critical task. These associations are used to form a weighted directed graph of technologies called 'association tech-graph' which is used for technology development, trend analysis, policymaking,...
Dynamic economic evaluation of distribution automation systems
, Article 2009 International Conference on Electric Power and Energy Conversion Systems, EPECS 2009 ; 2009 ; 9789948427155 (ISBN) ; Ehsan, M ; Sharif University of Technology
2009
Abstract
In a deregulated environment of power distribution industry, a comprehensive economic evaluation for the implementation of distribution automation (DA) systems is inevitable. Using the presented methodology in this paper and system dynamics approach, it is efficiently possible to deal with variation of the economic parameters such as the interest rate, inflation rate, energy supply cost, load growth, etc. In this paper, economic short-run and long-run impacts of DA systems are evaluated from utility point of view. Also economic benefits from customers' point of view are analyzed. A practical pricing strategy for maximizing the utility profit is suggested depending on the underlying market...
Some clarifications on the relation between bohmian quantum potential and mach’s principle
, Article International Journal of Theoretical Physics ; Volume 56, Issue 10 , 2017 , Pages 3096-3107 ; 00207748 (ISSN) ; Golshani, M ; Sharif University of Technology
2017
Abstract
Mach’s principle asserts that the inertial mass of a body is related to the distribution of other distant bodies. This means that in the absence of other bodies, a single body has no mass. In this case, talking about motion is not possible, because the detection of motion is possible only relative to other bodies. But in physics we are faced with situations that are not fully Machian. As in the case of general theory of relativity where geodesics exist in the absence of any matter, the motion has meaning. Another example which is the main topic of our discussion, refers to Bohmian quantum mechanics, where the inertial mass of a single particle does not vanish, but is modified. We can call...
Some clarifications about the bohmian geodesic deviation equation and raychaudhuri's equation
, Article International Journal of Modern Physics A ; Volume 33, Issue 3 , 2018 ; 0217751X (ISSN) ; Golshani, M ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
2018
Abstract
One of the important and famous topics in general theory of relativity and gravitation is the problem of geodesic deviation and its related singularity theorems. An interesting subject is the investigation of these concepts when quantum effects are considered. Since the definition of trajectory is not possible in the framework of standard quantum mechanics (SQM), we investigate the problem of geodesic equation and its related topics in the framework of Bohmian quantum mechanics in which the definition of trajectory is possible. We do this in a fixed background and we do not consider the backreaction effects of matter on the space-time metric. © 2018 World Scientific Publishing Company
On the dynamics of gravity-induced wave function reduction
, Article International Journal of Modern Physics A ; Volume 36, Issue 26 , 2021 ; 0217751X (ISSN) ; Golshani, M ; Sharif University of Technology
World Scientific
2021
Abstract
In this study, we use the concept of Bohmian trajectories to present a dynamical and deterministic interpretation for the gravity-induced wave function reduction. We shall classify all possible regimes for the motion of a particle, based on the behavior of trajectories in the ensemble and under the influence of quantum and gravitational forces. In the usual approaches all the information is obtained from the wave function evolution. But, on the basis of Bohm's deterministic quantum theory, we can investigate the motion of the particle during the reduction processes. This leads to analytical and numerical results for the reduction time and equation of motion of the particle. In this regard, a...
Engineered nanopores-based armchair graphene nanoribbon fet with resonant tunneling performance
, Article IEEE Transactions on Electron Devices ; Volume 66, Issue 12 , 2019 , Pages 5339-5346 ; 00189383 (ISSN) ; Ahmadi, V ; Faez, R ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
This article presents a novel armchair graphene nanoribbon (AGNR) field-effect transistor with engineered nanopores for resonant tunneling. Two rectangular nanopores are punched to create two potential barriers and one quantum well. Channel and source and drain contacts are AGNR, indicating structure homogeneity. Nonequilibrium Green's function and Poisson's equations are used for structural analysis. The input variables are well width (WW), drain voltage (VD), and barrier width (BW). The effects of repositioning nanopores and AGNR type (i.e., semiconductor and semimetal) are also studied. The impact of the parameters on the density of states, transmission probabilities, peak current (IP)...
A Bohmian approach to the perturbations of non-linear Klein-Gordon equation
, Article Pramana - Journal of Physics ; Volume 87, Issue 2 , 2016 ; 03044289 (ISSN) ; Golshani, M ; Sarbishei, M ; Sharif University of Technology
Indian Academy of Sciences
2016
Abstract
In the framework of Bohmian quantum mechanics, the Klein-Gordon equation can be seen as representing a particle with mass m which is guided by a guiding wave φ(x) in a causal manner. Here a relevant question is whether Bohmian quantum mechanics is applicable to a non-linear Klein-Gordon equation? We examine this approach for φ4(x) and sine-Gordon potentials. It turns out that this method leads to equations for quantum states which are identical to those derived by field theoretical methods used for quantum solitons. Moreover, the quantum force exerted on the particle can be determined. This method can be used for other non-linear potentials as well
Deriving relativistic Bohmian quantum potential using variational method and conformal transformations
, Article Pramana - Journal of Physics ; Volume 86, Issue 4 , 2016 , Pages 747-761 ; 03044289 (ISSN) ; Golshani, M ; Sarbishei, M ; Sharif University of Technology
2016
Abstract
In this paper we shall argue that conformal transformations give some new aspects to a metric and changes the physics that arises from the classical metric. It is equivalent to adding a new potential to relativistic Hamilton-Jacobi equation. We start by using conformal transformations on a metric and obtain modified geodesics. Then, we try to show that extra terms in the modified geodesics are indications of a background force. We obtain this potential by using variational method. Then, we see that this background potential is the same as the Bohmian non-local quantum potential. This approach gives a method stronger than Bohm's original method in deriving Bohmian quantum potential. We do not...
Nano drug-delivery systems for management of AIDS: liposomes, dendrimers, gold and silver nanoparticles
, Article Nanomedicine ; Volume 18, Issue 3 , 2023 , Pages 279-302 ; 17435889 (ISSN) ; Mousazadeh, M ; Taji, S ; Bahmani, A ; Khashayar, P ; Azimzadeh, M ; Mostafavi, E ; Sharif University of Technology
Newlands Press Ltd
2023
Abstract
AIDS causes increasing mortality every year. With advancements in nanomedicine, different nanomaterials (NMs) have been applied to treat AIDS and overcome its limitations. Among different NMs, nanoparticles (NPs) can act as nanocarriers due to their enhanced solubility, sustained release, targeting abilities and facilitation of drug-dose reductions. This review discusses recent advancements in therapeutics for AIDS/HIV using various NMs, mainly focused on three classifications: polymeric, liposomal and inorganic NMs. Polymeric dendrimers, polyethylenimine-NPs, poly(lactic-co-glycolic acid)-NPs, chitosan and the use of liposomal-based delivery systems and inorganic NPs, including gold and...
Robust and rapid converging adaptive beamforming via a subspace method for the signal-plusinterferences covariance matrix estimation
, Article IET Signal Processing ; Vol. 8, Issue. 5 , July , 2014 , pp. 507-520 ; ISSN: 17519675 ; Bastani, M. H ; Sharif University of Technology
2014
Abstract
The presence of the desired signal (DS) in the training snapshots makes the adaptive beamformer sensitive to any steering vector mismatch and dramatically reduces the convergence rate. Even the performance of the most of the existing robust adaptive beamformers is degraded when the signal-to-noise ratio (SNR) is increased. In this study, a high converging rate robust adaptive beamformer is proposed. This method is a promoted eigenspace-based beamformer. In this paper, a new signal-plus-interferences (SPI) covariance matrix estimator is proposed. The subspace of the ideal SPI covariance matrices is exploited and the estimated covariance matrix is projected into this subspace. This projection...
Quantifying the impacts of agricultural alteration and climate change on the water cycle dynamics in a headwater catchment of Lake Urmia Basin
, Article Agricultural Water Management ; Volume 270 , 2022 ; 03783774 (ISSN) ; Danesh Yazdi, M ; Sharif University of Technology
Elsevier B.V
2022
Abstract
The rapid shrinkage of Lake Urmia over the past two decades has raised serious environmental concerns. Several restoration plans have been proposed to reduce agricultural water consumption to supply a remarkable fraction of the lake's environmental flow requirement. However, an accurate and realistic evaluation of the effectiveness of these plans in reducing agricultural water consumption across the basin is still poorly understood. This study assessed the water-saving potential of agricultural alteration in a snow-dominated catchment in the Lake Urmia Basin. In particular, we explored the impact of crop pattern alteration via reducing the cultivation area and employing different irrigation...