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sp 2/sp 3 bonding ratio dependence of the band-gap in graphene oxide
, Article European Physical Journal B ; Volume 92, Issue 4 , 2019 ; 14346028 (ISSN) ; Akbari, I ; Ebrahimi, M. R ; Sharif University of Technology
Springer Heidelberg
2019
Abstract
Abstract: Although the band-gap in pure graphene is zero, the oxygenated graphene could have a considerable band-gap. The D/G peak intensity ratio is known as a measure of the size of sp3∕sp2 domains in graphene oxide (GO) sheets and determines the band-gap in GO sheets. Characterization results showed that the photoluminescence (PL) spectra of GO suspensions has a peak at ~604 nm and also the I(D)/I(G) intensity ratio of GO suspensions is 1.73. After reduction, a redshift appeared at PL spectrum (at 650 nm) and the I(D)/I(G) intensity ratio decrease to 1.26. Our results showed that the band-gap in GO is related to the I(D)/I(G) intensity ratio of GO suspensions and offers a mechanism for...
simulation of thermo-hydro-mechanical processes at Soultz-sous-Forêts
, Article Energies ; Volume 15, Issue 24 , 2022 ; 19961073 (ISSN) ; Singh, M ; Mahyapour, R ; Tangirala, S. K ; Bär, K ; Sass, I ; Sharif University of Technology
MDPI
2022
Abstract
Porosity and permeability alteration due to the thermo-poro-elastic stress field disturbance from the cold fluid injection is a deciding factor for longer, more economic, and safer heat extraction from an enhanced geothermal system (EGS). In the Soultz-sous-Forêts geothermal system, faulted zones are the main flow paths, and the resulting porosity–permeability development over time due to stress reorientation is more sensitive in comparison with the regions without faulted zones. Available operational and field data are combined through a validated numerical simulation model to examine the mechanical impact on the pressure and temperature evolution. Results shows that near the injection...
proposal for tunable dual channel transmitter and mechano-optical switch based on photonic crystal
, Article Applied Optics ; Volume 51, Issue 32 , 2012 , Pages 7784-7787 ; 00036935 (ISSN) ; Noshad, M ; Sharif University of Technology
OSA - The Optical Society
2012
Abstract
In this article we propose a novel mechano-optical switch and dual channel transmitter based on photonic crystal. The device consists of two waveguides and an elliptical cavity in a square lattice structure. Two optical signals at separate wavelengths are inserted in the input waveguide. The elliptical cavity can be rotated using a mechanical force, which results in the control of transmission efficiency at each of the wavelengths. In addition, rotation of the cavity can be considered as a switching action, which changes on-off states of the output signals
prediction of time to failure in stress corrosion cracking of 304 stainless steel in aqueous chloride solution by artificial neural network
, Article Protection of Metals and Physical Chemistry of Surfaces ; Volume 45, Issue 5 , 2009 , Pages 610-615 ; 20702051 (ISSN) ; Shahrabi, T ; Baigi, V ; Shafiei, A. M ; Sharif University of Technology
2009
Abstract
Despite the numerous researches in Stress Corrosion Cracking (SCC) risk of austenitic stainless steels in aqueous chloride solution, no formulation or reliable method for prediction of time to failure as a result of SCC has yet been defined. In this paper, the capability of artificial neural network for estimation of the time to failure for SCC of 304 stainless steel in aqueous chloride solution together with sensitivity analysis has been expressed. The output results showed that artificial neural network can predict the time to failure for about 74% of the variance of SCC experimental data. Furthermore, the sensitivity analysis also demonstrated the effects of input parameters (Temperature,...
pH control using the nonlinear multiple models, switching, and tuning approach
, Article Industrial and Engineering Chemistry Research, Washington ; Volume 39, Issue 5 , 2000 , Pages 1311-1319 ; 08885885 (ISSN) ; Shahrokhi, M ; Sharif University of Technology
ACS
2000
Abstract
pH control is known to be a challenging problem due to its highly nonlinear nature. Several control strategies are proposed for controlling pH processes among which is the strong acid equivalent scheme. Although this technique is robust to modeling error, the controller performance is degraded if the titration curve undergoes large changes. To overcome this problem, two control schemes that are based on the strong acid equivalent strategy and that use the multiple models, switching, and tuning approach are proposed in this work. For modeling, both fixed and adaptive models are considered. An experimental setup is used to evaluate the performance of the proposed scheme. The effectiveness of...
pH and thermal dual-responsive poly(NIPAM-co-GMA)-coated magnetic nanoparticles via surface-initiated RAFT polymerization for controlled drug delivery
, Article Materials Science and Engineering C ; Volume 108 , 2020 ; Kohestanian, M ; Streb, C ; Sharif University of Technology
Elsevier Ltd
2020
Abstract
Herein, a novel type of multifunctional magnetic nanoparticles with dual thermal and pH-responsive behavior was fabricated as the carrier for delivery of doxorubicin (DOX). Fe3O4@SiO2 magnetic nanoparticles, were grafted with polymer brushes consisting of poly (NIPAM-co-GMA) (PNG) chains via surface initiated reversible addition-fragmentation chain transfer (SI-RAFT) polymerization. The polymer brushes were then modified with hydrazine groups as DOX binding sites. The prepared multifunctional magnetic nanoparticles were characterized by FT-IR, 1H NMR, XPS, TGA, DLS, VSM, GPC, TEM, and XRD analysis. The in vitro drug release of the multifunctional magnetic nanoparticles was examined at 37 °C...
miRNA-encapsulated abiotic materials and biovectors for cutaneous and oral wound healing: Biogenesis, mechanisms, and delivery nanocarriers
, Article Bioengineering and Translational Medicine ; 2022 ; 23806761 (ISSN) ; Yousefiasl, S ; Kumar, A ; Dabbagh Moghaddam, F ; Rahimmanesh, I ; Samandari, M ; Jamwal, S ; Maleki, A ; Mohammadi, A ; Rabiee, N ; Cláudia Paiva-Santos, A ; Tamayol, A ; Sharifi, E ; Makvandi, P ; Sharif University of Technology
John Wiley and Sons Inc
2022
Abstract
MicroRNAs (miRNAs) as therapeutic agents have attracted increasing interest in the past decade owing to their significant effectiveness in treating a wide array of ailments. These polymerases II-derived noncoding RNAs act through post-transcriptional controlling of different proteins and their allied pathways. Like other areas of medicine, researchers have utilized miRNAs for managing acute and chronic wounds. The increase in the number of patients suffering from either under-healing or over-healing wound demonstrates the limited efficacy of the current wound healing strategies and dictates the demands for simpler approaches with greater efficacy. Various miRNA can be designed to induce...
lifetime improvement based on event occurrence patterns for wireless sensor networks using multi-objective optimization
, Article Wireless Personal Communications ; Volume 125, Issue 4 , 2022 , Pages 3333-3349 ; 09296212 (ISSN) ; Movaghar, A ; Teshnehlab, M ; Sharif University of Technology
Springer
2022
Abstract
The wide range of wireless sensor network applications has made it an interesting subject for many studies. One area of research is the controlled node placement in which the location of nodes is not random but predetermined. Controlled node placement can be very effective when either the price of the sensor nodes is high or the sensor coverage is of a specific type and it is necessary to provide special characteristics such as coverage, lifetime, reliability, delay, efficiency or other performance aspects of a wireless sensor network by using the minimum number of nodes. Since node placement algorithms are NP-Hard problems, and characteristics of a network are often in conflict with each...
k-anonymity-based horizontal fragmentation to preserve privacy in data outsourcing
, Article Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics), 11 July 2012 through 13 July 2012, Paris ; Volume 7371 LNCS , 2012 , Pages 263-273 ; 03029743 (ISSN) ; 9783642315398 (ISBN) ; Hadavi, M. A ; Jalili, R ; Sharif University of Technology
Springer
2012
Abstract
This paper proposes a horizontal fragmentation method to preserve privacy in data outsourcing. The basic idea is to identify sensitive tuples, anonymize them based on a privacy model and store them at the external server. The remaining non-sensitive tuples are also stored at the server side. While our method departs from using encryption, it outsources all the data to the server; the two important goals that existing methods are unable to achieve simultaneously. The main application of the method is for scenarios where encrypting or not outsourcing sensitive data may not guarantee the privacy
Zygomatic bone registration based on a modified student's mixture model method
, Article 26th National and 4th International Iranian Conference on Biomedical Engineering, ICBME 2019, 27 November 2019 through 28 November 2019 ; 2019 , Pages 88-92 ; 9781728156637 (ISBN) ; Mobaraki, M ; Ahmadian, A ; Bayat, M ; Bahrami, N ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2019
Abstract
Point Set Registration (PSR) of anatomic parts is used in different fields such as Patient Specific Implant (PSI) design in Computer Assisted Surgery (CAS) procedure. We designed a modified rigid PSR method based on student's-t mixture model. The proposed method is compared with Coherent Point Drift (CPD) registration method. Higher convergence speed and the lower error value are the advantages of the suggested algorithm in compare with CPD. In our method, the number of iterations decreases by about 69%, and the final error improvement was about 7% in comparison with CPD. The robustness of the proposed algorithm makes it beneficial to be used in the procedure of designing PSI in both...
Zwitterion-functionalized MIL-125-NH2-based thin-film nanocomposite forward osmosis membranes: towards improved performance for salt rejection and heavy metal removal
, Article New Journal of Chemistry ; Volume 46, Issue 31 , 2022 , Pages 15205-15218 ; 11440546 (ISSN) ; Bagherzadeh, M ; Navi, H ; Nikkhoo, M ; Amini, M ; Sharif University of Technology
Royal Society of Chemistry
2022
Abstract
In the current study, thin-film nanocomposite membranes (TFN-Mx) based on a zwitterion-functionalized metal-organic framework (MOF) have been developed for the forward osmosis (FO) salt-water separation process. The active polyamide layer was formed through the interfacial polymerization of the m-phenylenediamine aqueous phase (with or without the presence of MIL-125-NH-CC-Cys) and the trimesoyl chloride organic phase. In comparison with the results from the surface of the unmodified membrane, a nanofiller-incorporated TFN-M0.10 membrane represents a smoother and more wettable surface that collaborates synergically to enhance the membrane antifouling ability. Among the examined membranes,...
ZrOCl2·8H2O on montmorillonite K10 accelerated conjugate addition of amines to α,β-unsaturated alkenes under solvent-free conditions
, Article Tetrahedron ; Volume 62, Issue 4 , 2006 , Pages 672-677 ; 00404020 (ISSN) ; Eftekhari-Sis, B ; Abdollahifar, A ; Khalili, B ; Sharif University of Technology
2006
Abstract
At room temperature, ZrOCl2·8H2O on montmorillonite K10 efficiently catalyzes conjugate addition of amines to a variety of conjugated alkenes such as α,β-unsaturated carbonyl compounds, carboxylic esters, nitriles and amides under solvent-free conditions. The catalyst can be recycled for subsequent reactions without any appreciable loss of efficiency. © 2005 Elsevier Ltd. All rights reserved
ZrN fractal-graphene-based metamaterial absorber in the visible and near-IR regimes
, Article Optik ; Volume 237 , 2021 ; 00304026 (ISSN) ; Choudhury, P. K ; Niaz Akhtar, M ; Sharif University of Technology
Elsevier GmbH
2021
Abstract
The absorption characteristics of zirconium nitride (ZrN)-based metamaterial absorber of fractal geometry are studied. The proposed absorber is comprised of fractal metasurface at the top having subwavelength-sized periodic pattern of specially designed ZrN circular nano-discs arranged over silicon dioxide (SiO2) substrate. A tri-layer graphene, owing to its exhibiting better tunability, is introduced at the interface of metasurface and substrate. The bottom side of SiO2 is coated with silver nanolayer to block transmission. The absorptivity essentially depends on the kind of fractal design used in metasurface to configure the absorber. The obtained results exhibit the absorption...
ZnO-incorporated polyvinylidene fluoride/poly(ε-caprolactone) nanocomposite scaffold with controlled release of dexamethasone for bone tissue engineering
, Article Applied Physics A: Materials Science and Processing ; Volume 128, Issue 8 , 2022 ; 09478396 (ISSN) ; Mohammadi, M ; Mashayekhan, S ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH
2022
Abstract
Here we report on the development of a hybrid nanofibrous scaffold made from polyvinylidene fluoride (PVDF) nanofibers embedding zinc oxide nanorods (ZnOns), and poly(ε-caprolactone) (PCL) nanofibers incorporating dexamethasone (DEX)-loaded chitosan nanoparticles using dual-electrospinning method. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and tensile analysis were carried out for physiochemical characterization of the scaffolds, followed by DEX release profile. In addition, an MTT assay was conducted to assess the viability of mouse bone marrow-derived mesenchymal stem cells (mBMSCs) on the hybrid nanofibrous scaffold....
ZnO-PEDOT core-shell nanowires: An ultrafast, high contrast and transparent electrochromic display
, Article Solar Energy Materials and Solar Cells ; Volume 145 , 2016 , Pages 200-205 ; 09270248 (ISSN) ; Safarian, S ; Kolahdouz, M ; Fathipour, M ; Ahamdi, V ; Sharif University of Technology
Elsevier
2016
Abstract
We report fabrication of ultrafast and high contrast transparent electrochromic device desired for display application using nanostructured electrode. To this end, poly (3,4-ethylenedioxythiophene) (PEDOT) nanotubes were synthesized by simple electrochemical polymerization method on hydrothermally grown ZnO nanowires array as electrode. The PEDOT nanotubes of 20 nm average wall thickness characterized by SEM, TEM and EDS. The manufactured cell was subjected to electrochemical test and spectrophotometery that showed high contrast of 54% during ultrafast switching time of <2.2 ms. In addition, high coloration efficiency of 234 cm2/C, ultrahigh diffusion coefficient of 2.01×10-4 cm2/s and...
ZnO quantum dots-graphene composites: Formation mechanism and enhanced photocatalytic activity for degradation of methyl orange dye
, Article Journal of Alloys and Compounds ; Volume 663 , 2016 , Pages 738-749 ; 09258388 (ISSN) ; Outokesh, M ; Tayebi, M ; Shafikhani, A ; Şengör, S. S ; Sharif University of Technology
Elsevier Ltd
2016
Abstract
The current study demonstrates homogenous decorating of zinc oxide quantum dots (QDs) onto graphene oxide (GO) surface via simple chemical method. The AFM image exhibited that the prepared graphene was 0.8 nm thick and hence practically monolayer. Average size of the ZnO QDs was estimated by transmission electron microscopy around 3 nm. Instrumental and chemical analyses demonstrated formation of a strong bond between ZnO QDs and GO, through C-O-Zn and C-Zn bridges. The UV-visible spectra displayed that the introduction of graphene sheets to ZnO QDs resulted in higher absorption intensity of UV as well as widening of adsorption window toward visible light for ZnO-Graphene due to chemical...
ZnO nanowires from nanopillars: influence of growth time
, Article Current Nanoscience ; Volume 5, Issue 4 , 2009 , Pages 479-484 ; 15734137 (ISSN) ; Roozbehi, M ; Akhavan, O ; Moshfegh, A. R ; Sharif University of Technology
2009
Abstract
A double-tube vapor phase transport system has been used to grow ZnO nanostructures. Nanopillars, nanorods and nanowires of zinc oxide were synthesized on Au nanoparticle catalyst depending on source-substrate distance and temperature gradient in the quartz tube. In addition, influence of growth time and substrate temperature on the morphology of the nanorods and nanowires were also investigated. The scanning electron microscope (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM) were employed to further understand the nanostructures growth mechanism on various temperatures and growth time steps. Longer length (>4μm) with hexagonal-cross-sectional nanowires, in [002]...
ZnO nanoparticles prepared by electrical arc discharge method in water
, Article Materials Chemistry and Physics ; Volume 118, Issue 1 , 2009 , Pages 6-8 ; 02540584 (ISSN) ; Iraji zad, A ; Mahdavi, M ; Ahadian, M. M ; Sharif University of Technology
2009
Abstract
We produced ZnO nanoparticles by high current electrical arc discharge of zinc electrodes in deionized (DI) water. X-ray diffraction (XRD) analysis shows formation of crystalline ZnO phase with hexagonal structure and 14 nm single crystalline domain size. Dynamic light scattering (DLS) result indicates that at 5 A arc current, the size of the particles is about 100 nm and increases by increasing the arc current. Absorption spectroscopy of the samples obtained at different arc currents shows an absorption edge on 370 nm which has a red shift by increasing the arc current. Band gap of the produced ZnO nanoparticles at 5 A arc current corresponds to 3.8 eV which decreases to 3.3 eV by...
ZnO nanoparticle/nanorod-based label-free electrochemical immunoassay for rapid detection of MMP-9 biomarker
, Article Biochemical Engineering Journal ; Volume 164 , 2020 ; Abdekhodaie, M. J ; Mousavi, S. A ; Taghipour, F ; Sharif University of Technology
Elsevier B.V
2020
Abstract
A label-free electrochemical biosensor was developed for the rapid detection of the matrix metalloproteinase 9 (MMP-9) biomarker on the basis of antibody immobilizing on the zinc oxide (ZnO) nanoparticle and ZnO nanorod electrodes. The charge transfer resistance (Rct) of the electrodes was used as the indicator for MMP-9 concentration, which was obtained through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The ZnO nanorod-based biosensor exhibited linear behavior in the MMP-9 concentration range of 1–1000 ng/ml, which is a wider range than the available concentration ranges for most of the conventional methods. The biosensor sensitivity was 32.5 μA/(decade × cm2)...
ZnAl nano layered double hydroxides for dual functional CRISPR/Cas9 delivery and enhanced green fluorescence protein biosensor
, Article Scientific Reports ; Volume 10, Issue 1 , 2020 ; Bagherzadeh, M ; Ghadiri, A. M ; Salehi, G ; Fatahi, Y ; Dinarvand, R ; Sharif University of Technology
Nature Research
2020
Abstract
Evaluation of the effect of different parameters for designing a non-viral vector in gene delivery systems has great importance. In this manner, 2D crystals, precisely layered double hydroxides, have attracted the attention of scientists due to their significant adjustability and low-toxicity and low-cost preparation procedure. In this work, the relationship between different physicochemical properties of LDH, including pH, size, zeta potential, and synthesis procedure, was investigated and optimized for CRISPR/Cas9 delivery and reverse fluorescence response to the EGFP. In this manner, ZnAl LDH and ZnAl HMTA LDH were synthesized and characterized and applied in the HEK-293 cell line to...