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A novel graphene nanoribbon field effect transistor with two different gate insulators
, Article Physica E: Low-Dimensional Systems and Nanostructures ; Volume 66 , 2015 , Pages 133-139 ; 13869477 (ISSN) ; Faez, R ; Haji Nasiri, S ; Sharif University of Technology
Elsevier
2015
Abstract
In this paper, a novel structure for a dual-gated graphene nanoribbon field-effect transistor (GNRFET) is offered, which combines the advantages of high and low dielectric constants. In the proposed Two Different Insulators GNRFET (TDI-GNRFET), the gate dielectric at the drain side is a material with low dielectric constant to form smaller capacitances, while in the source side, there is a material with high dielectric constant to improve On-current and reduce the leakage current. Simulations are performed based on self-consistent solutions of the Poisson equation coupled with Non-Equilibrium Green's Function (NEGF) formalism in the ballistic regime. We assume a tight-binding Hamiltonian in...
A seamless-pitched graphene nanoribbon field effect transistor
, Article Physica E: Low-Dimensional Systems and Nanostructures ; Volume 74 , November , 2015 , Pages 414-420 ; 13869477 (ISSN) ; Moravvej Farshi, M. K ; Faez, R ; Sharif University of Technology
Elsevier
2015
Abstract
This paper proposes a graphene nanoribbon field effect transistor (GNRFET) consisting of pitched semiconducting GNRs as the channels that are connected to the metallic graphene source/drain in a seamless fashion. We obtained the diagrams for frequency bandwidths, step time responses, and Nyquist stability for the seamless pitched GNRFET (SP-GNRFET) with a channel having 100 pitched GNRs at 10 nm pitch in the common source configuration with various dimensions of the GNRs. The aforementioned diagrams were also obtained for the pitched carbon nanotube field effect transistor (CNTFET) with a channel having 100 pitched CNTs at 10 nm pitch in the common source configuration with various...
Stability analysis in multiwall carbon nanotube bundle interconnects
, Article Microelectronics Reliability ; Volume 52, Issue 12 , 2012 , Pages 3026-3034 ; 00262714 (ISSN) ; Faez, R ; Moravvej Farshi, M. K ; Sharif University of Technology
2012
Abstract
Based on the transmission line model (TLM), we present an exact and general transfer function formula, useful for both single multiwall carbon nanotube (MWCNT) and MWCNT bundle interconnects. Using the standard parameters for 22-nm technology node we perform the Nyquist stability analysis, to investigate the dependence of the degree of relative stability for both single and bundle interconnects on the number of walls in each MWCNT its geometry and also on the bundle geometry. The numerical results, for 1- to 30-μm long interconnects composed of 3- to 7-wall-CNTs, show that by increasing the length or the outer shell diameter, both single and bundle interconnects become more stable. On the...
Stability analysis in graphene nanoribbon interconnects
, Article IEEE Electron Device Letters ; Volume 31, Issue 12 , 2010 , Pages 1458-1460 ; 07413106 (ISSN) ; Moravvej Farshi, M. K ; Faez, R ; Sharif University of Technology
2010
Abstract
We present a Nyquist stability criterion based on transmission line modeling for graphene nanoribbon (GNR) interconnects. This is the first instance that such an analysis has been presented for GNR, so far. In this analysis, the dependence of the degree of relative stability for multilayer GNR (MLGNR) interconnects on the geometry of each ribbon has been acquired. It is shown that, increasing the length and width, MLGNR interconnects become more stable
Electronic features of rippled graphene
, Article ICEE 2012 - 20th Iranian Conference on Electrical Engineering ; 2012 , Pages 170-172 ; 9781467311489 (ISBN) ; Moravvej Farshi, M. K ; Faez, R ; Bajelan, A ; Sharif University of Technology
2012
Abstract
Using tight binding theory the effect of topological ripples on the electronic band structure, density of states (DOS), and Fermi velocity of graphene are studied. The results show that by an increase in the ripple height the graphene Fermi velocity decreases and its DOS increases.- Moreover, we show that an increase in the ripple period causes the graphene band gap and DOS to decrease and its Fermi velocity to increase
Minimizing expected discounted cost in a queueing loss model with discriminating arrivals
, Article European Journal of Operational Research ; Volume 282, Issue 2 , 2020 , Pages 593-601 ; Ross, S ; Sharif University of Technology
Elsevier B.V
2020
Abstract
We consider a queuing loss system with heterogeneous skill based servers and Poisson arrivals. We first assume that each arrival has a vector (X1,…,Xn) of independent binary random variables with Xi=1 if server i is eligible to serve that arrival. The service time at server i is exponential with rate μi. Arrivals finding no servers that are both idle and eligible to serve them are lost. Assuming the system incurs a cost of one unit for each lost customer, our goal is to find the optimal policy for assigning arrivals to idle and eligible servers so as to minimize the expected discounted cost of the system. Later, we generalize our model by considering k server pools where each pool i is...
Stationary Measures on Homogeneous Spaces
, M.Sc. Thesis Sharif University of Technology ; Haji Mirsadeghi, Mir Omid (Supervisor) ; Nasiri, Meysam (Supervisor)
Abstract
Let be a sub-semigroup of SL(d;Z) which acts strongly irreducible on Rd, i.e. there is not any invariant finite union of nontrivial proper subspaces of Rd. acts on Td by homeomorphisms. We will show that under these assumptions every infinite invariant subset of Td under the action of is dense in Td. For instance, if x is a point in Td which is not rational, then x = Td. In this thesis, we will follow the method of Y. Benoist and J.F. Quint for proving such results. Their method is to prove some kind of rigidity for the stationary measures for the action of on Td. Actually, every atomless stationary measure is the lebesgue measure on Td which is invariant under all the elements of...
Information Theoretic Analysis of Smart Radio Environment
, Ph.D. Dissertation Sharif University of Technology ; Nasiri Kenari, Masoumeh (Supervisor) ; Mirmohseni, Mahtab (Co-Supervisor)
Abstract
In this thesis, we analyze the degree of freedom (DoF) of wireless multi-user networks in the presence of smart radio environment. The two most important wireless multi-user networks, K-user interference channel, and M*N wireless X network are considered and the effects of the presence of a smart radio environment on the DoF of these networks are evaluated. To this end, first, we consider Intelligent Reflecting Surfaces (IRSs), which are a practical model of smart radio environments and can control the propagation of waves toward the desired direction in the environment. Then, we consider the instantaneous relay as a general theoretical model, which is the most comprehensive model for smart...
Fabrication of porous scaffolds with decellularized cartilage matrix for tissue engineering application
, Article Biologicals ; Volume 48 , 2017 , Pages 39-46 ; 10451056 (ISSN) ; Mashayekhan, S ; Sharif University of Technology
Academic Press
2017
Abstract
Due to the avascular nature of articular cartilage, damaged tissue has little capacity for spontaneous healing. Three-dimensional scaffolds have potential for use in tissue engineering approach for cartilage repair. In this study, bovine cartilage tissue was decellularized and chemically crosslinked hybrid chitosan/extracellular matrix (ECM) scaffolds were fabricated with different ECM weight ratios by simple freeze drying method. Various properties of chitosan/ECM scaffolds such as microstructure, mechanical strength, swelling ratio, and biodegradability rate were investigated to confirm improved structural and biological characteristics of chitosan scaffolds in the presence of ECM. The...
A novel method for prediction of parameters of naturally fractured condensate reservoirs using pressure response analysis
, Article Journal of Natural Gas Science and Engineering ; Vol. 19, issue , July , 2014 , p. 13-22 ; ISSN: 18755100 ; Jamshidi, S ; Masihi, M ; Sharif University of Technology
2014
Abstract
Producing from gas condensate reservoirs under dew-point pressure and at constant temperature shows a complex behavior because of existing liquid condensate around the well. Zones with different mobilities generate three zones as a zone away from the well containing only gas, a zone having liquid around the well and finally a zone containing movable oil and gas. Existence of condensate around wellbore reduces gas relative permeability and as a result productivity index of the well will decrease. In fact, this condensate acts like an additional skin and investigating of this behavior can be difficult because of the complex fluid flow processes. Well test analysis in naturally fractured...
Optimal Batch Production for a Single Machine System with Rework
, M.Sc. Thesis Sharif University of Technology ; Haji, Ali Reza (Supervisor)
Abstract
This research attempts to develop the optimal solution for an inventory problem consisting of a single machine which produces items some of which may be defective. We assume that no shortages are allowed and all defective items are to be reworked. Setup cost for rework and waiting time of defectives are considered. This research consists of two different parts. In the first part we consider two different policies where in the first policy in each cycle after the regular production the machine is setup for the rework of defectives of the same cycle. In the second policy several cycles constitute a period. All the defectives produced in the period are reworked in the last cycle of that period....
The M/M/1 queue with inventory, lost sale, and general lead times
, Article Queueing Systems ; Volume 75, Issue 1 , January , 2013 , Pages 65-77 ; 02570130 (ISSN) ; Asmussen, S ; Haji, R ; Sharif University of Technology
2013
Abstract
We consider an M/M/1 queueing system with inventory under the (r,Q) policy and with lost sales, in which demands occur according to a Poisson process and service times are exponentially distributed. All arriving customers during stockout are lost. We derive the stationary distributions of the joint queue length (number of customers in the system) and on-hand inventory when lead times are random variables and can take various distributions. The derived stationary distributions are used to formulate long-run average performance measures and cost functions in some numerical examples
Optimal batch production with rework and non-zero setup cost for rework
, Article 2009 International Conference on Computers and Industrial Engineering, 6 July 2009 through 9 July 2009 ; 2009 , Pages 857-862 ; 9781424441365 (ISBN) ; Haji, R ; Haji, A ; Sharif University of Technology
2009
Abstract
This paper attempts to develop the optimal solution for an inventoryproblem consisting of a single machine which produces items some of which may bedefective. We assume that no shortages are allowed and all defective items areto be reworked. Setup cost for rework and waiting time of defectives areconsidered. We consider two different policies where in the first policy in eachcycle after the regular production the machine is setup for the rework ofdefectives of the same cycle. In the second policy several cycles constitute aperiod. All the defectives produced in the period are reworked in the last cycleof that period. At the end of the rework cycle the whole process starts allover again. One...
Revenue sharing contract for a VMI with one for one period policy
, Article Cogent Engineering ; Volume 5, Issue 1 , 2018 , Pages 1-19 ; 23311916 (ISSN) ; Afzalabadi, M ; Haji, R ; Sharif University of Technology
Cogent OA
2018
Abstract
In this article, we design a revenue-sharing contract to coordinate inventory control decisions in a serial supply chain consisting of one supplier, one vendor, and one retailer. We assume that the retailer faces Poisson demand and his unsatisfied demands will be lost. The retailer applies one-for-one period policy in which he constantly places an order for one unit of product to the vendor in a predetermined time interval which results in a deterministic demand for the vendor. Vendor orders the required quantity from supplier which will be immediately received at the vendor’s warehouse. Solution procedures are developed to find the equilibrium in the vendor managed inventory program with a...
Pricing and inventory decisions in a vendor managed inventory system with revenue sharing contract
, Article Uncertain Supply Chain Management ; Volume 6, Issue 3 , 2018 , Pages 299-320 ; 22916822 (ISSN) ; Afzalabadi, M ; Haji, R ; Sharif University of Technology
Growing Science
2018
Abstract
In this paper, we design a revenue sharing contract to coordinate pricing and inventory control decisions in a serial supply chain consisting of one supplier, one manufacturer and one retailer. We assume that the retailer faces Poisson demand and his unsatisfied demands will be lost. The retailer applies one-for-one period policy in which he constantly places an order for one unit of product to the manufacturer in a predetermined time interval which results in a deterministic demand for the manufacturer. Solution procedures are developed to find the equilibrium in the Vendor Managed Inventory (VMI) program with a revenue sharing contract, in which no party is willing to deviate from for the...
One-for-one period policy in a two-echelon inventory system with commoncycle and poisson demand rate for retailers
, Article 2009 International Conference on Computers and Industrial Engineering, CIE 2009 ; 2009 , Pages 831-834 ; 9781424441365 (ISBN) ; Tayebi, H ; Haji, B ; Sharif University of Technology
2009
Abstract
This paper deals with a two-echelon inventory system consisting of onesupplier and N retailers. Each retailer faces an independent Poisson demand withthe same rate and applies a new ordering policy called one-for-one- periodordering policy for its inventory control. In this ordering policy the ordersize is equal to one and the time interval between any two consecutive ordersforms a common fixed cycle. Thus, the supplier faces a deterministic demand andadopts a deterministic inventory policy. At each cycle he orders a batch of sizeN to his own supplier. Upon receipt of each batch he sends 1 unit of theproduct to each retailer with a transportation cost. In this paper, for theabove system we...
Developing a partial backlogging deteriorating inventory model with selling price dependant demand rate and cycle length dependant selling price
, Article 2008 IEEE International Conference on Industrial Engineering and Engineering Management, IEEM 2008, Singapore, 8 December 2008 through 11 December 2008 ; January , 2008 , Pages 198-202 ; 9781424426300 (ISBN) ; Sabahno, H ; Haji, R ; Sharif University of Technology
2008
Abstract
In this paper, we develop an inventory model with price dependant demand rate, under time value of money and inflation, finite time horizon, exponential backlogging rate and exponential deterioration rate with the objective of maximizing the present worth of the total system profit. Using a dynamic programming based solution algorithm, we are able to find the optimal sequence of the cycles and also to obtain different optimal selling prices and optimal order quantities for the cycles with unequal lengths, which have never been done before for our model. We also use a proper numerical example to show accuracy of the solution procedure. © 2008 IEEE
Production of extracellular protease and determination of optimise condition by bacillus licheniformis BBRC 100053
, Article Chemical Engineering Transactions ; Volume 21 , 2010 , Pages 1447-1452 ; 19749791 (ISSN) ; 9788895608051 (ISBN) ; Yaghmaei, S ; Haji Hosseini, R ; Sharif University of Technology
2010
Abstract
The production of protease by Bacillus licheniformis BBRC 100053 was studied. The most appropriate medium for the growth and protease production is composed of: lactose 1 %, yeast extract 0.5 %, peptone 0.5 %, KH 2PO4 0.1%, MgSO4.7H2O 0.02 %. Enzyme production corresponded with growth and reached a maximums level (589 U/ml) during the stationary phase at 35 °C, pH equivalent to 10 and with 150 rpm after 73 hours. Protease activity was highest at pH 8 and 45 °C. The best carbon sources are respectively lactose and maltose and the best nitrogen source is peptone The protease was highly active and stable from pH 7.0 to 11.0 with an optimum at pH 7-8.Thermo stability of the enzyme was considered...
The effect of inspection errors on the optimal batch size in reworkable production systems with scraps
, Article International Journal of Product Development ; Volume 10, Issue 1-3 , 2010 , Pages 201-216 ; 14779056 (ISSN) ; Shadrokh Sikari, S ; Shamsi, R ; Sharif University of Technology
2010
Abstract
The objective of this paper is to provide a framework to integrate the existence of products with imperfect-quality items, inspection errors, rework and scrap items into a single Economic Production Quantity (EPQ) model. To achieve this objective, a suitable mathematical model is defined and the optimal production lot size that minimises the total cost is obtained. Sensitivity analysis is carried out for this model. The sensitivity analysis results indicate that the model is very sensitive to defective proportions and type 1 errors of inspection. Nowadays, given the progress made, inspection errors are often ignored. But the findings of this study show that the values of EPQ and total cost...
Economic Lot Size Formula Under VMI Program with Poisson Demand
, Article Arabian Journal for Science and Engineering ; Vol. 39, issue. 10 , October , 2014 , p. 7459-7465 ; 13198025 ; Zokaee, S ; Haji, R ; Sharif University of Technology
2014
Abstract
Nowadays, inventory management plays a crucial role in manufacturing supply chains. Vendor-managed inventory (VMI) program is a collaborative initiative that shows considerable performances in managing inventories through the supply system. In this study, we discuss the VMI initiative in a serial manufacturing supply chain when there is an uncertainty in demand and provide an approximate closed-form formula for the economic lot size. In this paper, we consider a two-echelon supply chain system consisting of a manufacturer and a retailer. Under vendor-managed inventory program with centralized decision making, the manufacturer is authorized to manage inventories of all agreed upon stock...