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Temperature compensation in CMOS peaking current references
, Article IEEE Transactions on Circuits and Systems II: Express Briefs ; Volume 65, Issue 9 , 2018 , Pages 1139-1143 ; 15497747 (ISSN) ; Kananian, S ; Sharifkhani, M ; Sodagar, A. M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2018
Abstract
In this brief, modifications to the peaking current reference with MOS transistors operating in the subthreshold and the strong inversion region has been proposed by means of which very small currents with immunity to temperature variations on a chip can be obtained. Temperature compensation can be done by adding a source degeneration resistor to the conventional peaking current source structure. Design examples are provided for both weak and strong inversion operations with output currents of 1.5 μA and 40 μ A with less than 4% and 10% variation over the span of-40 °C to +100 °C, respectively. A prototype of the circuit operating in the weak and strong inversion region is designed,...
A four bit low power 165MS/s flash-SAR ADC for sigma-delta ADC application
, Article IEEE International Conference on Electronics, Circuits, and Systems, 6 December 2015 through 9 December 2015 ; Volume 2016-March , 2016 , Pages 153-156 ; 9781509002467 (ISBN) ; Khorami, A ; Eslampanah Sendi, M. S ; Hajsadeghi, K ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
A low power four bit mixed Successive Approximation Register (SAR)-Flash Analog to Digital Converter (ADC) for Sigma-Delta ADC applications is presented. The ADC uses three comparators in order to reduce the latency of typical SAR ADCs. Three comparators are used for conversion of 2 bits per one clock cycle. One of the Digital to Analog Converters (DACs) is replaced by three resistors which can save power and area. The ADC is simulated by Cadence Spectre using TSMC 0.18um COMS technology. The power consumption at 165MS/s and 1.8V supply voltage is 1.8mW. The SNDR and SFDR for 10MHz input are 19.8dB and 28.4dB, respectively
A low-power temperature-compensated CMOS peaking current reference in subthreshold region
, Article Proceedings - IEEE International Symposium on Circuits and Systems, 28 May 2017 through 31 May 2017 ; 2017 ; 02714310 (ISSN) ; 9781467368520 (ISBN) ; Kananian, S ; Zendehrouh, E ; Sharifkhani, M ; Sodagar, A. M ; Shabany, M ; Sharif University of Technology
2017
Abstract
In this paper, a new method to achieve very small current reference levels on integrated circuits with immunity to temperature variations using peaking current source with MOSFETs operating in subthreshold region is proposed. By adding a source degeneration resistor to the conventional peaking current source architecture, a zero temperature coefficient current can be generated. The proposed low-power circuit operating in the weak inversion region is designed, simulated, and fabricated in a 0.18-μm standard CMOS process. Measurement results verify the circuit operation with about 5% variation over the span of -40° C to +100° C (industrial temperature grade). The supplied current is designed...
Wireless interfacing to cortical neural recording implants using 4-FSK modulation scheme
, Article IEEE International Conference on Electronics, Circuits, and Systems, 6 December 2015 through 9 December 2015 ; Volume 2016 March , 2016 , Pages 221-224 ; 9781509002467 (ISBN) ; Judy, M ; Molaei, H ; Sodagar, A. M ; Sharifkhani, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2016
Abstract
This paper used a 4-level frequency shift keying (4-FSK) modulation scheme to enhance the density of wireless data transfer from implantable biomedical microsystems to the outside world. Modeling and simulation of the wireless channel for 4-FSK modulation in the case of a neural recording implant has been done. To realize the 4-FSK scheme, the modulator and demodulator circuits are proposed, designed and simulated in a 0.18-μm CMOS process, and in the 174-216 MHz frequency band at a data rate of 13.5 Mbps. Operated using a 1.8 V supply voltage, the modulator circuit consumes a power of 7.8 μW
Increasing BIOS Trust in Personal Computers Using Reconfigurable Devices
, M.Sc. Thesis Sharif University of Technology ; Bayat Sarmadi, Siavash (Supervisor)
Abstract
Due to the expansion of digital system threats, trusted computation with a new approach for countering such threats has emerged. This approach is based on using a hardware module for implementing a trusted platform (TPM). TPM includes a chipset and the trusted systems core. Nowadays many of mobile computers do include this technology. This hardware creates trust using a trust chain and expanding this trust to other parts of the system. The starting point in this chain is the computer BIOS. BIOS is the first code that the system usually executes. One of the most powerful recent attacks on computer systems is to infect the BIOS and other firmware. One of such complicated attacks is the rootkit...
Design of a Non-Bianry Analog to Digital Converterfor Impantable Neural Recording Microsystem
, M.Sc. Thesis Sharif University of Technology ; Sharifkhani, Mohammad (Supervisor) ; Sodagar, Amir Masoud (Supervisor)
Abstract
A new structure of implantable neural recording microsystem base on multiple valued logic (MVL) has been proposed. MVL is a new idea for reduction of occupied area and the power consumption of microelectronic. In another side, in implantable microsystems , occupied area and power consumption by this type of micro systems is a challenging problem in this field. Therefore, the problem of power consumption and occupied area can introduce as a prime stage of suggested microsystem completed design of convertor of analog to digital in usage of multiple level in this micro system worked. Design of convertor of analog to digital is a convertor of quaternary successive approximation. And also,...
Non-fragile control and synchronization of a new fractional order chaotic system
, Article Applied Mathematics and Computation ; Volume 222 , 2013 , Pages 712-721 ; 00963003 (ISSN) ; Delshad, S. S ; Hamidi Beheshti, M. T ; Tavazoei, M. S ; Sharif University of Technology
2013
Abstract
In this paper, we address global non-fragile control and synchronization of a new fractional order chaotic system. First we inspect the chaotic behavior of the fractional order system under study and also find the lowest order (2.49) for the introduced dynamics to remain chaotic. Then, a necessary and sufficient condition which can be easily extended to other fractional-order systems is proposed in terms of Linear Matrix Inequality (LMI) to check whether the candidate state feedback controller with parameter uncertainty can guarantee zero convergence of error or not. In addition, the proposed method provides a global zero attraction of error that guarantees stability around all existing...
Parameters calculation of transformer winding detailed model based on finite element method to study partial discharge
, Article International Review on Modelling and Simulations ; Volume 5, Issue 5 , October , 2012 , Pages 1995-2000 ; 19749821 (ISSN) ; Vakilian, M ; Enjavimadar, S. M ; Sharif University of Technology
Praise Worthy Prize
2012
Abstract
The first step to locate Partial Discharge in power transformers is to find a model that can clearly explain the behavior of the winding in high-frequency. The detailed model is one of the models used for the study of PD. One of the fundamental problems of the described model is to find its parameters. And the accuracy in calculating these parameters has significant impact on reducing the simulation error and PD locating. The current paper seeks to calculate the parameters of the detailed model 20kv distribution transformer winding by using the finite element method (FEM). Comparing the results of this model with pulse waveforms obtained from the PD to the winding in the laboratory...
A Mechanical model for flexible exercise bars to study the influence of the initial position of the bar on lumbar discs and muscles forces
, Article Proceedings of the Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBS, 25 August 2015 through 29 August 2015 ; Volume 2015-November , 2015 , Pages 3917-3920 ; 1557170X (ISSN) ; 9781424492718 (ISBN) ; Abdollahi, M ; Nikkhoo, M ; Hoviattalab, M ; Asghari, M ; Ashouri, S ; Nikpour, S ; Kahrizi, S ; Parnianpour, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
2015
Abstract
A single-degree-of-freedom model is considered for flexible exercise bars based on the lumped-element approach. By considering the side segment of a flexible bar as a cantilever beam with an equivalent mass at the free end, its free-vibration response, as well as the forced response under the excitation of the grip, are expressed parametrically. Experiments are performed on a particular flexible bar (FLEXI-BAR) in order to obtain numerical values for quantifying the model's parameters. The model is also computationally simulated to study the response of the flexible bar to various excitations. The results are imported into a multi-segment musculoskeletal software (AnyBody), where the effect...
Magnetoelectric nanocomposite scaffold for high yield differentiation of mesenchymal stem cells to neural-like cells
, Article Journal of Cellular Physiology ; Volume 234, Issue 8 , 2019 , Pages 13617-13628 ; 00219541 (ISSN) ; Soleimani, M ; Ghiass, M. A ; Hatamie, S ; Vakilian, S ; Zomorrod, M. S ; Sadeghzadeh, N ; Vossoughi, M ; Hosseinzadeh, S ; Sharif University of Technology
Wiley-Liss Inc
2019
Abstract
While the differentiation factors have been widely used to differentiate mesenchymal stem cells (MSCs) into various cell types, they can cause harm at the same time. Therefore, it is beneficial to propose methods to differentiate MSCs without factors. Herein, magnetoelectric (ME) nanofibers were synthesized as the scaffold for the growth of MSCs and their differentiation into neural cells without factors. This nanocomposite takes the advantage of the synergies of the magnetostrictive filler, CoFe 2 O 4 nanoparticles (CFO), and piezoelectric polymer, polyvinylidene difluoride (PVDF). Graphene oxide nanosheets were decorated with CFO nanoparticles for a proper dispersion in the polymer through...
Hydrogenated graphene oxide (H-G-SiO2) Janus structure: Experimental and computational study of strong piezo-electricity response
, Article Journal of Physics D: Applied Physics ; Volume 53, Issue 17 , 2020 ; Alidoosti, M ; Hosseinzadeh, A ; Seyyedi, S. M. S ; Elahi, M ; Pourfath, M ; Mohajerzadeh, S ; Sharif University of Technology
Institute of Physics Publishing
2020
Abstract
We have investigated the piezoelectric response of the hydrogenated graphene oxide (H-G-SiO2) stacks both experimentally and theoretically. The piezoresponse force microscopy method and density-functional theory (DFT) calculations were used to study the piezoresponse effect of this structure from both experimental and computational point of views. A mono-layer graphene, made by chemical vapour deposition method, is deposited on Si/SiO2 substrate and its surface is then functionalized with hydrogen atoms. The vertical piezoresponse, observed by piezoresponse force microscopy, is measured to be about 2146 pC N-1, that is comparable to the reported state of the art piezoelectric materials such...
An ultra-wideband 3-dB quadrature hybrid with multisection broadside stripline tandem structure
, Article Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering ; Volume 77 LNICST , 2012 , Pages 672-681 ; 18678211 (ISSN) ; 9783642351549 (ISBN) ; Majedi, S. M. S ; Farzaneh, F ; Sharif University of Technology
2012
Abstract
Design of an Ultra-Wideband 3-dB quadrature (90°) Hybrid using ADS and HFSS softwares plus Measurement report are presented. Simultaneous Use of these two softwares lead to fast and accurate design procedure. The coupler is realized in broadside stripline and with the connection of coupled regions in tandem structure. The measured data agrees well with the expected values from simulations, and shows a good ultra wide bandwidth response over the frequency range of 1-10 GHz. Measurements showed an amplitude unbalance of ±1.5 dB, a phase unbalance of 90°±7° , and an isolation and a return loss characteristics of more than 14 dB over the frequency of 1 to 10 GHz
Broadside coupler Channels 1 to 10 GHz
, Article Microwaves and RF ; Volume 51, Issue 1 , 2012 ; 07452993 (ISSN) ; Majedi, S. M. S ; Farzaneh, F ; Sharif University of Technology
2012
Tensile deformation mechanisms at different temperatures in the Ni-base superalloy GTD-111
, Article Journal of Materials Processing Technology ; Volume 155-156, Issue 1-3 , 2004 , Pages 1900-1904 ; 09240136 (ISSN) ; Nategh, S ; Isac, M ; Zebarjad, S. M ; Sharif University of Technology
2004
Abstract
The Ni-base superalloy GTD-111 is employed in high-power stationary gas turbines because of its high temperature strength and oxidation resistance. The temperature dependence of the tensile behavior of GTD-111 has been studied by tensile tests in the temperature range of 25-900°C with a constant strain rate of 10-4s-1. The results showed an abnormal tensile property variation with increasing temperature. The yield strength decreased slightly with temperature up to about 650°C and then increased between 650 and 750°C. Above 750°C, a rapid decrease in the yield strength was found. The tensile strength showed a similar behavior except for its maximum that occurred at 650°C. The elongation...
Cell-imprinted substrates act as an artificial niche for skin regeneration
, Article ACS Applied Materials and Interfaces ; Vol. 6, Issue. 15 , 2014 , Pages 13280-13292 ; ISSN: 19448244 ; Bonakdar, S ; Taghinejad, H ; Satarifard, V ; Heidari, M ; Majidi, M ; Sharifi, S ; Peirovi, A ; Saffar, S ; Taghinejad, M ; Abdolahad, M ; Mohajerzadeh, S ; Shokrgozar, M. A ; Rezayat, S. M ; Ejtehadi M. R ; Dalby, M. J ; Mahmoudi, M ; Sharif University of Technology
2014
Abstract
Bioinspired materials can mimic the stem cell environment and modulate stem cell differentiation and proliferation. In this study, biomimetic micro/nanoenvironments were fabricated by cell-imprinted substrates based on mature human keratinocyte morphological templates. The data obtained from atomic force microscopy and field emission scanning electron microscopy revealed that the keratinocyte-cell-imprinted poly(dimethylsiloxane) casting procedure could imitate the surface morphology of the plasma membrane, ranging from the nanoscale to the macroscale, which may provide the required topographical cell fingerprints to induce differentiation. Gene expression levels of the genes analyzed...
Development of grid resource discovery service based on semantic information
, Article SpringSim '07: Proceedings of the 2007 spring simulaiton multiconference ; Volume 1 , 2007 , Pages 141-148 ; 07359276 (ISSN) ; 1565553128 (ISBN); 9781565553125 (ISBN) ; Moshkenani, M. S ; Sharif University of Technology
2007
Abstract
Grid computing is a type of parallel and distributed system that provides the possibility of sharing, choosing and collecting the autonomous resources (such as computer, software, databases, and equipments) that are distributed geographically. Resource discovery is one of the key subjects in distributed systems and especially Grids. We should consider that Grid consists of different applications that each of them consist of different hardware and software resources, therefore recognizing these resources is important in a Grid system. Classical approaches to Grid resource discovery are either centralized or hierarchical [1] (and will maybe prove inefficient as the scale of Grid systems...
Effect of nanoclay on improved rheology properties of polyacrylamide solutions used in enhanced oil recovery
, Article Journal of Petroleum Exploration and Production Technology ; Volume 5, Issue 2 , June , 2015 , Pages 189-196 ; 21900558 (ISSN) ; Khalili Nezhad, S. S ; Kamari, M ; Hemmati, M ; Masihi, M ; Bazgir, S ; Sharif University of Technology
Springer Verlag
2015
Abstract
Recently, a renewed interest arises in the application of nanotechnology for the upstream petroleum industry. In particular, adding nanoparticles to fluids may drastically benefit enhanced oil recovery (EOR) and improve well drilling, by changing the properties of the fluid, rocks wettability alteration, advanced drag reduction, strengthening the sand consolidation, reducing the interfacial tension and increasing the mobility of the capillary trapped oil. In this study, we focus on roles of clay nano-particles on polymer viscosity. Polymer-flooding schemes for recovering residual oil have been in general less than satisfactory due to loss of chemical components by adsorption on reservoir...
Polyurethane/clay nanocomposites reinforced with carbon and glass fibres: study of mechanical and thermal properties, and the effect of electron beam irradiation
, Article Plastics, Rubber and Composites ; Volume 46, Issue 9 , 2017 , Pages 413-420 ; 14658011 (ISSN) ; Mousavian, S. M. A ; Razavi, S. M ; Ahmadi, S. J ; Izadipanah, M ; Sharif University of Technology
2017
Abstract
Polyurethane (PU) nanocomposites with 0, 1, 3, 5, and 7 wt-% nanoclay contents were prepared. X-ray diffraction patterns, transmission electron microscopy images, tensile test, and thermogravimetric analysis were utilised to reveal the morphological, mechanical, and thermal-resistant properties of the prepared nanocomposites. The exfoliated structure was obtained for nanoclay contents up to 3 wt-%. Incorporation of nanoclay to the PU matrix prompted the thermal stability of the polymer. A nanocomposite filled with 3 wt-% nanoclay showed the best tensile strength in the prepared nanocomposites. Subsequently, the nanocomposite with the 3 wt-% nanoclay was reinforced with carbon and glass...
Post-buckling analysis of geometrically imperfect nanoparticle reinforced annular sector plates under radial compression
, Article Computers and Concrete ; Volume 26, Issue 1 , 2020 , Pages 21-30 ; Forsat, M ; Mollaee, S ; Barati, M. R ; Afshari, B. M ; Hamouda, A. M. S ; Sharif University of Technology
Techno-Press
2020
Abstract
Buckling and post-buckling behaviors of geometrically imperfect annular sector plates made from nanoparticle reinforced composites have been investigated. Two types of nanoparticles are considered including graphene oxide powders (GOPs) and silicone oxide (SiO2). Nanoparticles are considered to have uniform and functionally graded distributions within the matrix and the material properties are derived using Halpin-Tsai procedure. Annular sector plate is formulated based upon thin shell theory considering geometric nonlinearity and imperfectness. After solving the governing equations via Galerkin’s technique, it is showed that the post-buckling curves of annular sector plates rely on the...
Linear and non-linear dynamic methods toward investigating proprioception impairment in non-specific low back pain patients
, Article Frontiers in Bioengineering and Biotechnology ; Volume 8 , 2020 ; Davoudi, M ; Hoviattalab, M ; Abedi, M ; Bervis, S ; Parnianpour, M ; Brumagne, S ; Khalaf, K ; Sharif University of Technology
Frontiers Media S.A
2020
Abstract
Central nervous system (CNS) uses vision, vestibular, and somatosensory information to maintain body stability. Research has shown that there is more lumbar proprioception error among low back pain (LBP) individuals as compared to healthy people. In this study, two groups of 20 healthy people and 20 non-specific low back pain (NSLBP) participants took part in this investigation. This investigation focused on somatosensory sensors and in order to alter proprioception, a vibrator (frequency of 70 Hz, amplitude of 0.5 mm) was placed on the soleus muscle area of each leg and two vibrators were placed bilaterally across the lower back muscles. Individuals, whose vision was occluded, were placed...