Loading...
Search for: zheng--s
0.108 seconds

    Luttinger-Ward Functional and Slave-rotor Analysis of U(1) Quantum Spin Liquids

    , Ph.D. Dissertation Sharif University of Technology Zheng, XiaMing (Author) ; Kargarian, Mehdi (Supervisor)
    Abstract
    In this thesis we put forward a new theoretical framework that combines the LuttingerWard (LW) functional methodology with a slave-rotor construction. As such, the strongly correlated electronic problem is systematically mapped onto a weakly coupled system of two primary excitations: spinons and chargons. In this projective construction, the electronic degrees of freedom are fractionalized, thereby enabling the study of emergent phenomena in a more tractable manner. Starting from the Hubbard model defined on a triangular lattice, two computational approaches are developed and lead to self-consistent equations for the Green’s functions. The first approach is based on Hartree-Fock... 

    Guest editorial introduction to the special issue on large-scale visual sensor networks: Architectures and applications

    , Article IEEE Transactions on Circuits and Systems for Video Technology ; Volume 31, Issue 4 , 2021 , Pages 1249-1252 ; 10518215 (ISSN) Spagnolo, P ; Aghajan, H ; Bebis, G ; Gong, S ; Loutfi, A ; Sigal, L ; Zheng, W. S ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2021

    Spinon kondo lattice in quantum spin liquids using the slave-rotor formalism

    , Article Physical Review B ; Volume 110, Issue 11 , 2024 ; 24699950 (ISSN) Zheng, Xia Ming ; Kargarian, M ; Sharif University of Technology
    2024
    Abstract
    Motivated by recent experimental observations of Kondo resonances in cobalt atoms on single layer 1T-TaSe2, we theoretically investigate the effect of coupling a U(1) quantum spin liquid with a spinon Fermi surface to a lattice of Anderson impurities. Within the slave-rotor formalism, we find that above a critical coupling strength between the spin liquid and impurity lattice, the spinons hybridize to form heavy quasiparticles near the Fermi level, realizing a spinon Kondo lattice phase analogous to heavy fermion materials. Using the Bethe-Salpeter equation and accounting for emergent gauge fluctuations, we compute the spectral density and density of states, revealing the formation of... 

    Modeling viscosity of CO2-N2 gaseous mixtures using robust tree-based techniques: extra tree, random forest, GBoost, and LightGBM

    , Article ACS Omega ; Volume 8, Issue 15 , 2023 , Pages 13863-13875 ; 24701343 (ISSN) Zheng, H ; Mahmoudzadeh, A ; Amiri Ramsheh, B ; Hemmati Sarapardeh, A ; Sharif University of Technology
    American Chemical Society  2023
    Abstract
    Carbon dioxide (CO2) has an essential role in most enhanced oil recovery (EOR) methods in the oil industry. Oil swelling and viscosity reduction are the dominant mechanisms in an immiscible CO2-EOR process. Besides numerous CO2 applications in EOR, most oil reservoirs do not have access to natural CO2, and capturing it from flue gas and other sources is costly. Flue gases are available in huge quantities at a significantly lower price and can be considered economically viable agents for EOR operations. In this work, four powerful machine learning algorithms, namely, extra tree (ET), random forest (RF), gradient boosting (GBoost), and light gradient boosted machine (LightGBM) were utilized to... 

    Advanced optimizer for maximum power point tracking of photovoltaic systems in smart grid: A roadmap towards clean energy technologies

    , Article Renewable Energy ; Volume 206 , 2023 , Pages 1326-1335 ; 09601481 (ISSN) Zheng, S ; Shahzad, M ; Asif, H. M ; Gao, J ; Muqeet, H. A ; Sharif University of Technology
    Elsevier Ltd  2023
    Abstract
    With the increased load demand and generation cost of electricity, renewable energy sources (RES) provide cost effective and environment-friendly solution. Integration of solar energy includes the challenges of finding the Maximum Power Point (MPP) to achieve the maximum power from the solar. Combining RESs with distributed generation (DG) comes with the challenges of voltage regulation and frequency mismatch. In this work, a novel approach of Robust Antlion Optimizer (ALO) algorithm is implemented for MPP tracking in solar photovoltaic (PV) system and charge controllers are designed for storage system while the DC to AC converters have been designed to match RESs’ frequency with that of DG.... 

    Modulating glucose metabolism and relieving hypoxia for enhanced Chemo/Photoimmunotherapy with photosensitizing enzymatic nanodrugs

    , Article Chemical Engineering Journal ; Volume 498 , 2024 ; 13858947 (ISSN) Zheng, Z ; Lu, S ; Wu, Y ; Basak Kayitmazer, A ; Ahmad, A ; Ramzan, N ; Shahid Rafique, M ; Yang, J ; Zhou, X ; Xu, Y ; Si, Y ; Sharif University of Technology
    2024
    Abstract
    Photoimmunotherapy by photodynamic therapy (PDT) induces immunogenic cell death (ICD), providing anti-tumor treatment in a safe, precise, minimally invasive way. However, PDT-demanded massive oxygen consumption exacerbates the hypoxia and creates an acidic tumor microenvironment (TME), leading to an anaerobic glycolysis and immune escape condition. In this study, a natural anti-tumor resveratrol (RSV) nanodrug was introduced via Fe3+ coordination flash nanoprecipitation (cFNP) for enhanced aqueous solubility to specifically downregulate the expression of Pyruvate kinase M2 (PKM2) and lactate dehydrogenase A (LDHA), reduce the glucose resorption and lactate production, tipping the cellular... 

    Hyperion: a wearable augmented reality system for text extraction and manipulation in the air

    , Article Proceedings of the 8th ACM Multimedia Systems Conference, MMSys 2017, 20 June 2017 through 23 June 2017 ; 2017 , Pages 284-295 ; 9781450350020 (ISBN) Chatzopoulos, D ; Bermejo, C ; Huang, Z ; Butabayeva, A ; Zheng, R ; Golkarifard, M ; Hui, P ; Sharif University of Technology
    2017
    Abstract
    We develop Hyperion a Wearable Augmented Reality (WAR) system based on Google Glass to access text information in the ambient environment. Hyperion is able to retrieve text content from users' current view and deliver the content to them in different ways according to their context.We design four work modalities for different situations that mobile users encounter in their daily activities. In addition, user interaction interfaces are provided to adapt to different application scenarios. Although Google Glass may be constrained by its poor computational capabilities and its limited battery capacity, we utilize code-level offloading to companion mobile devices to improve the runtime... 

    Lyophilizable Polymer-Lipid Hybrid Nanoparticles with High Paclitaxel Loading

    , Article ACS Applied Nano Materials ; Volume 7, Issue 16 , 2024 , Pages 19194-19210 ; 25740970 (ISSN) Zheng, Z ; Wu, Y ; Ahmad, A ; Ramzan, N ; Kayitmazer, A. B ; Zhou, X ; Xu, Y ; Sharif University of Technology
    2024
    Abstract
    Lyophilization is a prevalent technique for preparing paclitaxel (PTX) clinical formulations. However, the instability of PTX nanoparticles poses challenges in producing lyophilized formulations. Such an instability involves maintaining stable dispersions and structural integrity during lyophilization. To tackle these issues, flash nanoprecipitation method is employed to prepare highly stable and loaded lyophilizable diPTX-SS nanoparticles, achieving over a month of nanosuspension stability and 91 wt % loading capacity. Furthermore, adjusting the concentrations and stabilizer ratios allows for controlled nanoparticle preparation with surface structures suitable for lyophilization. The... 

    Catalytic converter reducing dual fuel (natural gas/diesel) engine emissions

    , Article Scientia Iranica ; Volume 6, Issue 5 , 2000 , Pages 75-81 ; 10263098 (ISSN) Sallamie, N ; Kazemeini, M ; Soltanieh, M ; Checkel, M. D ; Badakhshan, A ; Zheng, M ; Mirosh, E. A ; Sharif University of Technology
    Sharif University of Technology  2000
    Abstract
    Using natural gas combined with diesel fuel in diesel engines provides a considerable contribution to modern industrial societies in order to control air pollution and, also, generalize and facilitate the use of public vehicles. In spite of the attractive features of this idea, including reduction of NO(X) and particulates, there is an important burden imposed upon the system at low to intermediate torques, namely high concentration of CO and unburned total hydrocarbons (THC), mostly composed of methane. In this work, based upon the oxidation of CO and unburned HCs and through experimental results, application of a monolithic oxidizing bifunctional catalytic converter as a novel... 

    Comparison between single, dual and triple rapid serial visual presentation paradigms for P300 speller

    , Article Proceedings - 2018 IEEE International Conference on Bioinformatics and Biomedicine, BIBM 2018, 3 December 2018 through 6 December 2018 ; 2019 , Pages 2635-2638 ; 9781538654880 (ISBN) Mijani, A. M ; Shamsollahi, M. B ; Sheikh Hassani, M ; Jalilpour, S ; Schmidt H ; Griol D ; Wang H ; Baumbach J ; Zheng H ; Callejas Z ; Hu X ; Dickerson J ; Zhang L ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2019
    Abstract
    P300 based Speller systems are a typical application of BCIs that can be used as a communication device for users with spinal cord injury. In this paper, three different RSVP paradigms; single, dual and triple RSVP are compared in terms of character detection accuracy and ITR to find the optimal communication method for these users. Three subjects were tested to compare these methods in offline mode. The results of this comparison shows that character detection accuracy for the single, dual and triple RSVP paradigms are 0.78, 0.63 and 0.64, respectively. The mean of ITR for the single, dual and triple RSVP paradigms was also recorded to be 3.6534, 7.72 and 11.5 bit/min, respectively.... 

    Efficient ROS activation by highly stabilized aqueous ICG encapsulated upconversion nanoparticles for tumor cell imaging and therapeutics

    , Article Chemical Engineering Journal ; Volume 452 , 2023 ; 13858947 (ISSN) Wu, Y ; Yuan, C ; Jia, X ; Zheng, Z ; Yang, X ; Yang, J ; Basak Kayitmazer, A ; Ahmad, A ; Ramzan, N ; Xu, Y ; Sharif University of Technology
    Elsevier B.V  2023
    Abstract
    Dye-sensitized upconversion nanoparticles (UCNPs) have gained significant interest in biological applications. However, previous attempts to utilize these dye-sensitized UCNPs in the aqueous environment suffer from dramatic decline in the upconversion luminescence (UCL) intensity and problems with nanoparticles aggregation and water quenching. By employing indocyanine green (ICG) as a hydrophobic amplifier and energy harvester for UCNPs, we use a general, facile, and kinetically controlled mixing technology—flash nanoprecipitation (FNP)—to prepare aqueous stable ICG-sensitized UCNPs encapsulated by a biocompatible block copolymer poly (ethylene glycol)-b-poly (lactic-co-glycolic acid... 

    Deposition and water repelling of temperature-responsive nanopesticides on leaves

    , Article Nature Communications ; Volume 14, Issue 1 , 2023 ; 20411723 (ISSN) Tang, J ; Tong, X ; Chen, Y ; Wu, Y ; Zheng, Z ; Kayitmazer, A. B ; Ahmad, A ; Ramzan, N ; Yang, J ; Huang, Q ; Xu, Y ; Sharif University of Technology
    Nature Research  2023
    Abstract
    Pesticides are widely used to increase agricultural productivity, however, weak adhesion and deposition lead to low efficient utilization. Herein, we prepare a nanopesticide formulation (tebuconazole nanopesticides) which is leaf-adhesive, and water-dispersed via a rapid nanoparticle precipitation method, flash nanoprecipitation, using temperature-responsive copolymers poly-(2-(dimethylamino)ethylmethylacrylate)-b-poly(ε-caprolactone) as the carrier. Compared with commercial suspensions, the encapsulation by the polymer improves the deposition of TEB, and the contact angle on foliage is lowered by 40.0°. Due to the small size and strong van der Waals interactions, the anti-washing efficiency... 

    Engineered biodegradable nanopesticides for efficient leaf deposition and plant fungicides

    , Article AIChE Journal ; Volume 70, Issue 6 , 2024 ; 00011541 (ISSN) Tong, X ; Tang, J ; Wang, J ; Wu, Y ; Zheng, Z ; Yuan, C ; Kayitmazer, A. B ; Ahmad, A ; Ramzan, N ; Yang, J ; Huang, Q ; Xu, Y ; Sharif University of Technology
    2024
    Abstract
    Pesticides are indispensable in agricultural development, but their effectiveness is often hindered by natural factors like rain-off and degradation. Herein, tebuconazole nanopesticides (TEB NPs) with leaf-adhesive, water-stable, and small-sized were successfully prepared by flash nanoprecipitation using the biodegradable polyethylene glycol-b-poly (lactic-co-glycolic acid) as a carrier. The nanopesticides could be efficiently deposited on plant leaves with uniform distribution and exhibited a 14° lower contact angle with foliage compared to commercial suspensions. The encapsulation of TEB within the polymer enhanced its resistance to photolysis, resulting in a 5-h extension of its... 

    The relationship between an EFL teacher's gender and students' willingness to communicate

    , Article International Journal of Communication and Linguistic Studies ; Volume 10, Issue 4 , 2013 , Pages 17-29 ; 23277882 (ISSN) Khosravizadeh, P ; Pakzadian, S. S
    Common Ground Publishing  2013
    Abstract
    Learning a foreign language encompasses a process of trial and error that can lead to the progression of the learner's interlanguage, meaning that the learners make use of their language knowledge that receives feedback and brings about progress through diagnosis of the problems and being corrected by the teacher. Therefore, there exists a need to analyze the underlying reasons causing the students to remain taciturn with a low willingness to communicate (WTC) during a language class. There has been much work done investigating the role of the learner's stable personal characteristics (traits) along with their situational changes at a specific time (states) that influence the student's... 

    Design and development of a miniaturized roto-translational motion platform for microaerial vehicle identification

    , Article IEEE Aerospace and Electronic Systems Magazine ; Volume 39, Issue 12 , 2024 , Pages 24-35 ; 08858985 (ISSN) Abdollahi, M. R ; Pourtakdoust, S. H ; Mousavi, S. M. S
    IEEE  2024
    Abstract
    Accurate system identification (SI) is essential for flight controller design of unmanned aerial vehicles and microaerial vehicles (MAVs). SI can be performed either in frequency or time domain using flight test data. As flight testing is often costly and may even lead to catastrophic events before some flight stability analysis is at hand, a low-cost 5 degree-of-freedom free motion platform (FMP) is designed and used for initial identification of MAVs via wind tunnel testing. A typical MAV is constructed as a test case and equipped with inertial sensors for testing and validation purposes. The proposed FMP allows for both rotational as well as translational motions that in turn provide for... 

    An automated simple algorithm for realistic pore network extraction from micro-tomography images

    , Article Journal of Petroleum Science and Engineering ; Vol. 123, issue , 2014 , pp. 164-171 ; ISSN: 09204105 Rabbani, A ; Jamshidi, S ; Salehi, S
    2014
    Abstract
    Using 3-D scanned data to analyze and extract pore network plays a vital role in investigation of porous media's characteristics. In this paper, a new simple method is developed to detect pores and throats for analyzing the connectivity and permeability of the network. This automated method utilizes some of the common and well-known image processing functions which are widely accessible by researchers and this has led to an easy algorithm implementation. In this method, after polishing and quality control of images, using city-block distance function and watershed segmentation algorithm, pores and throats are detected and 3-D network is produced. This method can also be applied on 2-D images... 

    Discrimination of heart arrhythmias using novel features in heart rate phase space

    , Article Computing in Cardiology ; Volume 40 , Sept , 2013 , Pages 1035-1038 ; 23258861 (ISSN); 9781479908844 (ISBN) Moharreri, S ; Rezaei, S ; Salavatian, S
    2013
    Abstract
    In this paper, we try to recognize and distinguish different groups of arrhythmia using novel features which have been obtained from the heart rate's phase space in recent years. For this purpose, we used Triangular Phase Space Mapping (TPSM) and Parabolic Phase Space Mapping (PPSM). For recognition, we used three groups of 15 subjects using the Physionet database (Arrhythmia, Congestive Heart Failure (CHF), and Atrial Fibrillation (AF)) with Normal Sinus Rhythm (NSR). The obtained features discriminate arrhythmia from NSR by p

    An intelligent hybrid classification algorithm integrating fuzzy rule-based extraction and harmony search optimization: Medical diagnosis applications

    , Article Knowledge-Based Systems ; Volume 220 , 2021 ; 09507051 (ISSN) Mousavi, S. M ; Abdullah, S ; Akhavan Niaki, S. T ; Banihashemi, S ; Sharif University of Technology
    Elsevier B.V  2021
    Abstract
    Uncertainty is a critical factor in medical datasets needed to be overcome for increasing diagnosis efficiency. This paper proposes an intelligent classification algorithm comprising a fuzzy rule-based approach, a harmony search (HS) algorithm, and a heuristic algorithm to classify medical datasets intelligently. Two fuzzy approaches, as well as orthogonal and triangular fuzzy sets, are first utilized to define the attributes of data. Then, an HS algorithm is integrated with a heuristic to generate fuzzy rules to select the best rules in the fuzzy rule-based systems. Moreover, to improve the performance of the proposed classification approach, a three-phase parameter tuning approach is... 

    Performance evaluation of shared hosting security methods

    , Article Proc. of the 11th IEEE Int. Conference on Trust, Security and Privacy in Computing and Communications, TrustCom-2012 - 11th IEEE Int. Conference on Ubiquitous Computing and Communications ; 2012 , Pages 1310-1315 ; 9780769547459 (ISBN) Mirheidari, S. A ; Arshad, S ; Khoshkdahan, S ; Sharif University of Technology
    2012
    Abstract
    Shared hosting is a kind of web hosting in which multiple websites reside on one webserver. It is cost-effective and makes the administration easier for websites' owners. However, shared hosting has some performance and security issues. In default shared hosting configuration, all websites' scripts are executed under the webserver's user account regardless of their owners. Therefore, a website is able to access other websites' resources. This security problem arises from lack of proper isolation between different websites hosted on the same webserver. In this survey, we have examined different methods for handling mentioned security issue. Also we evaluated the performance of mentioned... 

    The behaviour of an artificially cemented sandy gravel

    , Article Geotechnical and Geological Engineering ; Volume 23, Issue 5 , 2005 , Pages 537-560 ; 09603182 (ISSN) Haeri, S. M ; Hosseini, S. M ; Toll, D. G ; Yasrebi, S. S ; Sharif University of Technology
    2005
    Abstract
    The major section of the city of Tehran, Iran has been developed on cemented coarse-grained alluvium. This deposit consists of gravely sand to sandy gravel with some cobbles and is dominantly cemented by carbonaceous materials. In order to understand the mechanical behaviour of this soil, a series of undrained triaxial compression tests and unconfined compression tests were performed on uncemented and artificially cemented samples. Portland cement type I was used as the cementation agent for preparing artificially cemented samples. Uncemented samples and lightly cemented samples (1.5% cement) tested at high confining pressure showed contractive behaviour accompanied with positive excess pore...