Loading...
Search for: reaction-time
0.006 seconds
Total 54 records

    Synthesis of tetrahydrothiopyrano[2,3-b]indole [60]fullerene derivatives via hetero-diels–alder reaction of c60 and α,β-unsaturated indole-2-thiones

    , Article Journal of Heterocyclic Chemistry ; Volume 54, Issue 2 , 2017 , Pages 911-915 ; 0022152X (ISSN) Matloubi Moghaddam, F ; Ghanbari, B ; Behzadi, M ; Baghersad, M. H ; Sharif University of Technology
    HeteroCorporation  2017
    Abstract
    Hetero-Diels–Alder reactions of [60]fullerene with α,β-unsaturated thio-oxindoles (3a, 3b, 3c), prepared from thio-oxindole 1 and heteroaromatic aldehydes (2a, 2b, 2c), to generate tetrahydrothiopyrano[2,3-b]indole [60]fullerene cycloadducts (5a, 5b, 5c) under thermal or microwave irradiation were described. The yields were improved, and the reaction time was decreased by conducting the reaction under microwave irradiation. © 2016 Wiley Periodicals, Inc  

    Reaction Time Comparison of Unambiguous Statements with
    Ambiguous and Garden Path Sentences

    , M.Sc. Thesis Sharif University of Technology Erfanian, Ali (Author) ; Salehi, Mohammad (Supervisor)
    Abstract
    The present study compares the reaction times in processing unambiguous sentences with three ambiguous statements of lexical, grouping and functional as well as garden path sentences. To this end, a special computer program was developed with the accuracy of micro seconds. Furthermore, a set of 25 items was prepared with acceptable levels of reliability and validity. Forty seven highly proficient subjects, all undergraduate students of Air Traffic Control, participated in this study. The results of the study showed no significant difference between the reaction times of grouping and functional ambiguities but garden path sentences showed the greatest difference with the other groups. All... 

    Thesis Submitted in Partial Fulfillment of the Requirements for the Master's Degree in TEFL

    , M.Sc. Thesis Sharif University of Technology Torabi, Fariba (Author) ; Salehi, Mohammad (Supervisor)
    Abstract
    In the last decades, Reaction Time research has been extended to cognitive science and more specifically human information-processing research and has gained momentum (Shim, 1996). The present study examined the reaction time in processing marked and unmarked structures with regard to the four types of conditionals (considered as unmarked, less marked, marked and strongly markedness, respectively) and prepositions (preposition pied piping that is considered as unmarked and preposition stranding as marked). To this end, two softwares were developed for which the items relating to conditionals were chosen from the Bernet’s test (1985) and the ones pertinent to prepositions were taken from... 

    Poly (Lactic acid) Synthesis through Polycondensation Method and Optimized Reaction Time

    , M.Sc. Thesis Sharif University of Technology Farzad, Ashkan (Author) ; Frounchi, Masoud (Supervisor) ; Dadbin, Sousan (Supervisor)
    Abstract
    Poly (Lacticacid) belongs to the family of aliphatic polyesters. PLA can be made from annually renewable resources to yield articles for use in either the industrial packaging field or the biocompatible /bioabsorbable medical device market. Production of PLA through polycondensation in an industrial way was the aim of this project. In order to have the appropriate reaction conditions a steel reactor was designed and constructed. Feasibilty of PLA production in the constructed reactor was investigated and the product was analyzed, using H-NMR and FT-IR spectrum analysis. The average molecular weight was measured by GPC and ubbelohde viscometery method. Studies have shown that oligomerization... 

    On water: A practical and efficient synthesis of benzoheterocycle derivatives catalyzed by nanocrystalline copper(II) oxide

    , Article Synthetic Communications ; Volume 40, Issue 4 , 2010 , Pages 607-614 ; 00397911 (ISSN) Sadjadi, S ; Hekmatshoar, R ; Ahmadi, S. J ; Hosseinpour, M ; Outokesh, M ; Sharif University of Technology
    Abstract
    Recyclable CuO nanoparticles provide an efficient, economic, and novel method for the synthesis of quinoxaline, benzoxazine, and benzothiazine. This method provides a wide range of substrate applicability, avoids the use of organic solvents, and gives benzoheterocycles in satisfactory yields  

    Power-law correlation in human EEG at various anaesthesia depths

    , Article IET 3rd International Conference MEDSIP 2006: Advances in Medical, Signal and Information Processing, Glasgow, 17 July 2006 through 19 July 2006 ; Issue 520 , 2006 , Pages 46- ; 0863416586 (ISBN); 9780863416583 (ISBN) Gifani, P ; Rabiee, H. R ; Hashemi, M. H ; Momenzadeh, S ; Taslimi, P ; Ghanbari, M ; Sharif University of Technology
    2006
    Abstract
    The depth of anaesthesia estimation has been of a great interest in recent decades. In this paper we present a new methodology to quantify the depth of anaesthesia by quantifying the power-law correlations of the EEG signal. Extraction of useful information about the nonlinear dynamics of the brain during anaesthesia has been proposed with the optimum fractal scaling exponent. This optimum solution is based on the best domain of box sizes in the detrended fluctuation analysis (DFA) algorithm which have meaningful changes at different depth of anaesthesia. The experimental results confirm that our new algorithm on the raw EEG data can clearly discriminate between aware to moderate and deep... 

    Investigation of Reaction Times and Maneuver for Bus Drivers Based on Road and Drivers Characteristics Using Driving Simulator

    , M.Sc. Thesis Sharif University of Technology Yahyazadeh, Ehsan (Author) ; Vaziri, Manouchehr (Supervisor)
    Abstract
    One of the most prominent issues in road safety is to observe reaction time and sight distance in geometric design. Various sight distances are available is Iran's specifications on "Geometric Design of Roadways" taken from the AASHTO standard from which stopping sight distance, decision sight distance and their corresponding car driver reaction times are noteworthy. This research puts effort in obtaining these values for bus drivers in Iran. To achieve this, a test designed using bus driving simulator apparatus, developed in K.N.Toosi University of Technology, was conducted on a number of bus drivers. Obtained results of driver behavior were then analyzed and compared to corresponding... 

    Acquiring Phrasal Verbs through Implicit and Explicit Instruction: Insights from Eye-tracking and Reaction time

    , M.Sc. Thesis Sharif University of Technology Faraji, Mohammad Javad (Author) ; Rezaei, Saeed (Supervisor) ; Hassanzadeh, Mohammad (Supervisor)
    Abstract
    English language is peppered with phrasal verbs (PhVs) and native speakers use them frequently and endlessly in daily life. However, due to various semantic and syntactic difficulties, polysemy, unpredictability, and learners’ L1 differences, this omnipresent aspect of English language morphology poses formidable challenges for learners in terms of fluency and accuracy, and leads them to resort to avoidance strategies. The problem has also been exacerbated with the arbitrariness of PhVs’ teaching methods prescribed by various textbooks. In order to shed more light on the ongoing debate over implicit and explicit types of instruction as two viable approaches to tackling PhVs, this study aimed... 

    Improvement of palm oil and sunflower oil blends by enzymatic interestrification

    , Article International Journal of Food Science and Technology ; Volume 46, Issue 5 , 2011 , Pages 1093-1099 ; 09505423 (ISSN) Yazdi, Z. K ; Alemzadeh, I ; Sharif University of Technology
    Abstract
    Palm oil (PO) and sunflower oil (SFO) blends with varying proportions were subjected to enzymatic interesterification (EIE) using a 1,3-specific immobilised lipase. The interesterified blends were evaluated for their slip melting point (SMP), solid fat content (SFC) at 10-40°C, p-anisidine value, peroxide value, free fatty acids (FFA), induction period of oxidation at 110°C (IP110) and composition of fatty acids by gas chromatography. Under EIE treatment, the blends of PO and SFO in different proportions (20:80, 40:60, 50:50, 60:40 and 80:20) had saturated and unsaturated fatty acid content in the range of 37.6-52.0% and 48.0-62.4%, respectively. The blends showed a considerable reduction in... 

    A green procedure for direct oxidation of organic halides to aldehydes and ketones catalyzed by a molybdate-based catalyst

    , Article New Journal of Chemistry ; Volume 39, Issue 5 , Feb , 2015 , Pages 3845-3851 ; 11440546 (ISSN) Bayat, A ; Shakourian Fard, M ; Ramezanpour, S ; Mahmoodi Hashemi, M ; Sharif University of Technology
    Royal Society of Chemistry  2015
    Abstract
    A molybdate-based heterogeneous magnetic catalyst was synthesized and used in direct oxidation of various primary and secondary organic halides to the corresponding aldehydes and ketones using 30% H2O2 as an oxidant in ethanol. Various organic halides were oxidized to their corresponding aldehydes and ketones in good to excellent yields. The catalyst system can be easily separated by applying an external magnetic field and reused for 6 runs without any significant loss of catalytic activity. The catalyst was fully characterized by FT-IR, SEM, TEM, EDS, XRD, VSM, ICP-AES techniques, and elemental analysis (CHN)  

    Regioselective bromination of aromatic amines and phenols using N-benzyl-DABCO tribromide

    , Article Synthetic Communications ; Volume 39, Issue 23 , 29 October , 2009 , Pages 4212-4220 ; 00397911 (ISSN) Matloubi Moghaddam, F ; Zargarani, D ; Sharif University of Technology
    2009
    Abstract
    N-Benzyl-DABCO tribromide, a stable, solid organic ammonium tribromide, has been used as a bromine source for the regioselective and high-yielding bromination of aromatic amines and phenols. Mono-bromination proceeds well in the presence of a stoichiometric amount of bromine source at room temperature  

    Synthesis, crystal structure and catalytic activity of a novel Mo(VI)-oxazoline complex in highly efficient oxidation of sulfides to sulfoxides by urea hydrogen peroxide

    , Article Inorganica Chimica Acta ; Volume 361, Issue 7 , 2008 , Pages 2019-2024 ; 00201693 (ISSN) Bagherzadeh, M ; Tahsini, L ; Latifi, R ; Ellern, A ; Woo, L. K ; Sharif University of Technology
    Elsevier S.A  2008
    Abstract
    Novel molybdenum complex, cis-[MoO2(phox)2] has been synthesized and characterized by IR, 1H NMR, elemental analyses (CHN), and X-ray molecular structure determination methods. This complex was found to be an efficient, selective catalyst for the oxidation of various sulfides to sulfoxides with urea hydrogen peroxide (UHP) in excellent yields (100% for diallylsulfide) and short reaction times (20 min) at room temperature. The catalytic system oxidizes diallylsulfide chemoselectively to its corresponding sulfoxide without any over oxidation in double bond. © 2007 Elsevier B.V. All rights reserved  

    One-pot synthesis of dithiocarbamates accelerated in water

    , Article Journal of Organic Chemistry ; Volume 71, Issue 9 , 2006 , Pages 3634-3635 ; 00223263 (ISSN) Azizi, N ; Aryanasab, F ; Torkiyan, L ; Ziyaei, A ; Saidi, M. R ; Sharif University of Technology
    2006
    Abstract
    Highly efficient one-pot reactions of amines and carbon disulfide with α,β-unsaturated compounds were carried out in water under a mild and green procedure with high yields. © 2006 American Chemical Society  

    Task-specific modulation of PFC activity for matching-rule governed decision-making

    , Article Brain Structure and Function ; Volume 226, Issue 2 , 2021 , Pages 443-455 ; 18632653 (ISSN) Parto Dezfouli, M ; Zarei, M ; Constantinidis, C ; Daliri, M. R ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2021
    Abstract
    Storing information from incoming stimuli in working memory (WM) is essential for decision-making. The prefrontal cortex (PFC) plays a key role to support this process. Previous studies have characterized different neuronal populations in the PFC for working memory judgements based on whether an originally presented stimulus matches a subsequently presented one (matching-rule decision-making). However, much remains to be understood about this mechanism at the population level of PFC neurons. Here, we hypothesized differences in processing of feature vs. spatial WM within the PFC during a matching-rule decision-making task. To test this hypothesis, the modulation of neural activity within the... 

    2,6-Bis(diphenylphosphino)pyridine: A simple ligand showing high performance in palladium-catalyzed CN coupling reactions

    , Article Tetrahedron Letters ; Vol. 55, issue. 30 , July , 2014 , p. 4098-4101 ; ISSN: 00404039 Nadri, S ; Rafiee, E ; Jamali, S ; Joshaghani, M ; Sharif University of Technology
    Abstract
    The use of commercially available 2,6-bis(diphenylphosphino)pyridine as a ligand in conjunction with K2CO3, DMAc and TBAB is an effective method for the palladium-catalyzed CN coupling of a variety of aryl halides with anilines, N-heterocyclic aromatic amines, and a cyclic secondary amine. The reactions proceed in good to excellent yield (up to 98%) while the loading of Pd(OAc)2 was as low as 0.025 mol %  

    A rapid and convenient synthesis of gem-bis(dithiocarbamate) derivatives from primary aliphatic amines, carbon disulfide, and aromatic aldehydes using boron trifluoride-diethyl etherate

    , Article Tetrahedron Letters ; Vol. 55, Issue. 25 , 2014 , Pages 3572-3575 ; ISSN: 00404039 Nemati, F ; Ghiyaei, A. G. G ; Notash, B ; Shayegan, M. H ; Amani, V ; Sharif University of Technology
    Abstract
    An efficient route for the synthesis of gem-bis(dithiocarbamate) derivatives is developed using dithiocarbamic acid salts generated from primary aliphatic amines and CS2. The method offers high yields, employs mild reaction conditions, and demonstrates excellent functional group compatibility. The structures of the products were confirmed spectroscopically and by X-ray analysis  

    Numerical investigation on the solid flow pattern in bubbling gas-solid fluidized beds: Effects of particle size and time averaging

    , Article Powder Technology ; Vol. 264, issue , September , 2014 , p. 466-476 Askarishahi, M ; Salehi, M. S ; Molaei Dehkordi, A ; Sharif University of Technology
    Abstract
    The effects of particle size on the solid flow pattern in gas-solid bubbling fluidized beds were investigated numerically using two-fluid model based on the kinetic theory of granular flow. In this regard, the set of governing equations was solved using finite volume method in two-dimensional Cartesian coordinate system. Glass bead particles with mean sizes of 880. μm, 500. μm, and 351. μm were fluidized by air flow at excess gas velocities of 0.2. m/s and 0.4. m/s. For particle diameters of 880 and 351. μm, the predicted characteristic times for solid dispersion were 0.14. s and 0.15. s, respectively, while characteristic times for solid diffusivity were 1.68. ms and 0.75. ms in the same... 

    Water dispersed magnetic nanoparticles (H2O-DMNPs) of γ-Fe2O3 for multicomponent coupling reactions: A green, single-pot technique for the synthesis of tetrahydro-4H-chromenes and hexahydroquinoline carboxylates

    , Article Tetrahedron Letters ; Volume 54, Issue 26 , 2013 , Pages 3344-3347 ; 00404039 (ISSN) Rostamnia, S ; Nuri, A ; Xin, H ; Pourjavadi, A ; Hosseini, S. H ; Sharif University of Technology
    2013
    Abstract
    Water dispersed magnetic nanoparticles (DMNPs) of γ-Fe 2O3 represent a simple and green catalyst for the rapid three-component synthesis of tetrahydro-4H-chromene and hexahydroquinoline carboxylate skeletons via single-pot domino Knoevenagel-Michael-cyclization reactions  

    Spike phase synchronization in delayed-coupled neural networks: Uniform vs. non-uniform transmission delay

    , Article Chaos ; Volume 23, Issue 1 , 2013 ; 10541500 (ISSN) Jalili, M ; Sharif University of Technology
    2013
    Abstract
    In this paper, we investigated phase synchronization in delayed dynamical networks. Non-identical spiking Hindmarsh-Rose neurons were considered as individual dynamical systems and coupled through a number of network structures such as scale-free, Erdos-Rényi, and modular. The individual neurons were coupled through excitatory chemical synapses with uniform or distributed time delays. The profile of spike phase synchrony was different when the delay was uniform across the edges as compared to the case when it was distributed, i.e., different delays for the edges. When an identical transmission delay was considered, a quasi-periodic pattern was observed in the spike phase synchrony. There... 

    Ionic modified crosslinked salep: A highly loaded and efficient heterogeneous organocatalyst

    , Article Carbohydrate Polymers ; Volume 92, Issue 2 , 2013 , Pages 2252-2256 ; 01448617 (ISSN) Pourjavadi, A ; Hosseini, S. H ; Fakoorpoor, S. M ; Sharif University of Technology
    2013
    Abstract
    In this work, a novel heterogeneous organocatalyst was synthesized by immobilization of hydroxide ions on the modified salep as a natural polymer. Because of the grafting of ionic polymer chains onto the salep backbone, catalyst has high loading level of hydroxide ions (3.01 mmol/g). The resulting catalyst shows excellent activity in the synthesis of 4H-benzo[b]pyrans in water at room temperature in short reaction times. The present catalyst and protocol represent a simple, ecologically safe and cost-effective route to synthesize 4H-benzo[b]pyrans with high product yield, as well as easy catalyst recycling