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    Si/Si, Si/SiO2 and SiO2/SiO2 fusion wafer bonding

    , Article Scientia Iranica ; Volume 10, Issue 4 , 2003 , Pages 477-480 ; 10263098 (ISSN) Motieifar, A ; Rashidian, B ; Sharif University of Technology
    Sharif University of Technology  2003
    Abstract
    The wafer bonding process has many applications in the fabrication of microelectronic, optoelectronic, power and micromachined devices. In this article, fusion bonding of silicon wafers and study of their interface are reported for the first time in Iran. Also, the bonding of two silicon wafers, with one (or both) of the wafers having a thermally grown silicon dioxide layer, has been performed and tested. © Sharif University of Technology, October 2003  

    An algorithm for geometrical uncertainty analysis in planar truss structures

    , Article Structural and Multidisciplinary Optimization ; Vol. 49, issue. 2 , February , 2014 , pp. 225-238 ; Online ISSN: 1615-1488 Aghabeigi, M ; Movahhedy, M. R ; Sharif University of Technology
    Abstract
    An algorithm is proposed for description of error accumulation during assembly process of planar truss structures. Specifically, given the tolerances of pre-fabricated members, the uncertainty in the position of nodes is calculated in terms of variances and covariances. Twoconstituent elements of planar trusses (i.e. two-bar unit cell and redundant member) are formulated based on linear models of kinematics and deformation mechanics. Subsequently, these models are combined together in a single algorithm to construct a suitable procedure for estimation of uncertainty zone of each node. Accuracy of the developed method is verified by comparing its results with outcomes of Monte Carlo... 

    Comparison between decolorization of denim fabrics with Oxygen and Argon glow discharge

    , Article Surface and Coatings Technology ; Volume 201, Issue 9-11 SPEC. ISS , 2007 , Pages 4926-4930 ; 02578972 (ISSN) Ghoranneviss, M ; Shahidi, S ; Moazzenchi, B ; Anvari, A ; Rashidi, A ; Hosseini, H ; Sharif University of Technology
    2007
    Abstract
    In this study, we have used a low temperature plasma, produced by a DC magnetron sputtering device, for decolorizing of denim fabrics, and the effect of using different gases such as Argon and Oxygen as the discharge medium have been investigated. The results obtained under equal periods of time have been compared and the effect of washing on the treated denims has been reported. © 2006 Elsevier B.V. All rights reserved  

    Investigation of metal absorption and antibacterial activity on cotton fabric modified by low temperature plasma

    , Article Cellulose ; Volume 17, Issue 3 , 2010 , Pages 627-634 ; 09690239 (ISSN) Shahidi, S ; Rashidi, A ; Ghoranneviss, M ; Anvari, A ; Rahimi, M. K ; Bameni Moghaddam, M ; Wiener, J ; Sharif University of Technology
    2010
    Abstract
    In this work, the silver particle absorption and antibacterial activity of cotton fabric when modified by low temperature plasma were investigated. The modification consisted of plasma pre-functionalization followed by one-step wet treatment with silver nitrate solution. Oxygen and nitrogen were used as the working gases in the system, and the results were compared. The results showed that nitrogen plasma-treated samples can absorb more silver particles than oxygen-treated samples, and thus the antibacterial activity of the samples in this case, which was analyzed by the counting bacteria test, was increased considerably  

    Multifunctional hyperelastic structured surface for tunable and switchable transparency

    , Article Applied Sciences (Switzerland) ; Volume 11, Issue 5 , 2021 , Pages 1-11 ; 20763417 (ISSN) Mahabadi, R. K ; Goudarzi, T ; Fleury, R ; Naghdabadi, R ; Sharif University of Technology
    MDPI AG  2021
    Abstract
    We leverage the crucial hyperelastic properties of a multifunctional structured surface to optimize the reconfigurability of the electromagnetic transmission under large nonlinear mechanical deformations. This multiphysics, multifunctional, hyperelastic structured surface (HSS) offers two simultaneous intriguing functionalities; tunability and switchability. It is made of copper reso-nators and a Polydimethylsiloxane (PDMS) substrate, which is one of the most favorable deformable substrates due to its hyperelastic behavior. The proposed HSS is fabricated via an original cost-effective technique and the multiphysics functionalities are captured in both experimental tests and numerical... 

    Principles of designing and fabricating of a laboratory vibro-fluidized bed dryer to study of moist materials fluidization

    , Article Amirkabir (Journal of Science and Technology) ; Volume 15, Issue 58 B , 2004 , Pages 385-397 ; 10150951 (ISSN) Sadeghi, M ; Khoshtaghaza, M. H ; Khayyat, A. A. A ; Sharif University of Technology
    2004
    Abstract
    To study of vibration effect on fluidization behaviour of high moisture materials, a laboratory vibro-fluidized bed dryer was designed and fabricated. The blower was selected based on transferring velocity of particles and pressure drop caused by airflow through the bedplate and the channels. It was centrifugal type with backward blades, static pressure of 3.5 kPa, flow rate of 0.4 m 3/s and impeller diameter of 0.4 m. The dryer was constructed with 4.9 kW electrical heater capacity, bed plate with holes diameter of I mm and 140626 holes/m 2. The dryer chamber was made of Plexiglass with 0.16×0.16 m square section and 0.5 m height The bedplate was vibrated mechanically, which was adjustable... 

    Optical modulation by surface states

    , Article Semiconductor Science and Technology ; Volume 18, Issue 1 , 2003 , Pages 60-67 ; 02681242 (ISSN) Darabi, E ; Khorasani, S ; Rashidian, B ; Sharif University of Technology
    2003
    Abstract
    In this paper, the effect of two-dimensional electron plasma formed on the surface of a semiconductor on the refraction phase of an optical beam is investigated. Both the density and effective mass of the surface state electrons can be controlled by a transverse electric field. While the surface density of electrons varies slowly with the applied field, their effective mass changes instantaneously. Therefore, a high bandwidth for the phase modulation can be obtained. It is expected that the device operates in the far-infrared region with a semiconductor as the base material. GaAs is one of the best candidates having both large dynamic range, and large ratio of free electron to the crystal... 

    Static pull-in analysis of micro-cantilevers in wet etching fabrication process

    , Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE), 9 November 2012 through 15 November 2012 ; Volume 9, Issue PARTS A AND B , November , 2012 , Pages 347-350 ; 9780791845257 (ISBN) Darvishian, A ; Moeenfard, H ; Ahmadian, M. T ; Sharif University of Technology
    2012
    Abstract
    Parallel micro actuators are mostly fabricated using the wet etching process within which the presence of capillary force and the resulting pull-in instabilities can severely affect the success of the fabrication process. In the case the capillary force is large enough then the beam like structure of the micro actuators is collapsed. The current paper investigates; static behavior of microcantilevers under effect of capillary force. It is observed that with increasing the instability number defined in the paper, the deflection of the micro-cantilevers is increased. This study shows in the wet etching fabrication process, if the distance between the beam and substrate is small enough, the... 

    Motion of deformable ring made of IPMC

    , Article Proceedings of SPIE - The International Society for Optical Engineering ; Volume 8409 , 2012 ; 0277786X (ISSN); 9780819490872 (ISBN) Firouzeh, A ; Alasty, A ; Ozmaeian, M ; National Institute of Standards and Technology; Asia Pacific Committee of Smart and Nano Materials; Nanyang Technol. Univ., Adv. Mater. Res. Cent.; The National Natural Science Foundation of China; Chinese Society of Composite Materials ; Sharif University of Technology
    2012
    Abstract
    In this paper application of Ionic Polymer Metal Composite (IPMC) as actuator in a deformable ring capable of locomotion is studied. Such a deformable ring moves as a result of gravitational force acting on its body when its shape changes. It can be used in exploration, search and rescue missions in future, where using conventional robots with rigid bodies and actuators is impossible. Large deformation induced by small stimulating voltage, low stiffness the sensing characteristics that in future work can be used in feedback control make IPMC a good choice for such an application. In this work first a model for IPMC is introduce that can be used in simulating deformation of IPMC in different... 

    Consistent Predictive Simulation of SRAM-Cell Performance Degradation Including Both MOSFET Fabrication Variation and Aging

    , Article 2nd IEEE Electron Devices Technology and Manufacturing Conference, EDTM 2018, 13 March 2018 through 16 March 2018 ; 2018 , Pages 31-33 ; 9781538637111 (ISBN) Gau, H ; Rohbani, N ; Maiti, T. K ; Navarro, D ; Miura-Mattausch, M ; Mattausch, H. J ; Takatsuka, H ; Sharif University of Technology
    Institute of Electrical and Electronics Engineers Inc  2018
    Abstract
    We have developed a methodology to simulate circuit aging including the device fabrication variation with less simulation effort. As an example a 6T SRAM cell has been investigated. It is demonstrated that the variability range of the circuit performance is further enhanced due to the long-term device aging. Among the device parameters, the impurity concentration variation plays a particularly important role for the circuit performance variation. However, most sensitive for the aging degradation is the channel-length variation, because it increases the aging effect drastically. Further, the individual aging of each MOSFET is strongly dependent on the actual stress during circuit operation. ©... 

    Improving the multi-step fabrication approach of copper nanofiber networks based transparent electrode for achieving superb conductivity and transparency

    , Article Materials Research Express ; Volume 6, Issue 9 , 2019 ; 20531591 (ISSN) Mohamadbeigi, N ; Angizi, S ; Sadrnezhaad, S. K ; Nikzad, M. J ; Sharif University of Technology
    Institute of Physics Publishing  2019
    Abstract
    Transparent Conductive Electrode (TCE), as an essential part of the optoelectronic devices, has become popular owing to its unique properties such as high optical transmittance and conductivity. Among utilized materials for fabrication of TCE, copper nanofibers (NFs)-network have been attracting much attention due to its extraordinary properties such as low sheet resistance, the scalable manufacturing and low-cost fabrication method. However, many challenges exist in the way of multi-step fabrication of network to increase the NFs continuity and consequently, improvement of their electrical conductivity as TCE. Herein, we report a deep investigation of the effective parameters on diameter... 

    Improving the multi-step fabrication approach of copper nanofiber networks based transparent electrode for achieving superb conductivity and transparency

    , Article Materials Research Express ; Volume 6, Issue 9 , 2019 ; 20531591 (ISSN) Mohamadbeigi, N ; Angizi, S ; Sadrnezhaad, S. K ; Nikzad, M. J ; Sharif University of Technology
    Institute of Physics Publishing  2019
    Abstract
    Transparent Conductive Electrode (TCE), as an essential part of the optoelectronic devices, has become popular owing to its unique properties such as high optical transmittance and conductivity. Among utilized materials for fabrication of TCE, copper nanofibers (NFs)-network have been attracting much attention due to its extraordinary properties such as low sheet resistance, the scalable manufacturing and low-cost fabrication method. However, many challenges exist in the way of multi-step fabrication of network to increase the NFs continuity and consequently, improvement of their electrical conductivity as TCE. Herein, we report a deep investigation of the effective parameters on diameter... 

    Low cost flexible pressure sensor using laser scribed GO/RGO periodic structure for electronic skin applications

    , Article Superlattices and Microstructures ; Volume 140 , 2020 Hosseindokht, Z ; Mohammadpour, R ; Asadian, E ; Paryavi, M ; Rafii Tabar, H ; Sasanpour, P ; Sharif University of Technology
    Academic Press  2020
    Abstract
    Considering electronic skin applications, a pressure sensor based on periodic structure of graphene oxide-reduced graphene oxide (GO-rGO) has been designed and fabricated based on a low cost direct laser writing technique by utilizing the laser diode of DVD drive's pickup head. The optimization of sensor structure has been performed using computational modelling through Finite Element Method (FEM) in the COMSOL environment. The optimized structure is fabricated based on the deposition of thin layer of GO on the surface of Kapton and the pattering is performed by laser irradiation. The fabricated sensor structure has been characterized structurally and functionally. The results show that the... 

    Photo-detector diode based on thermally oxidized TiO2 nanostructures/p-Si heterojunction

    , Article Journal of Applied Physics ; Volume 119, Issue 1 , 2016 ; 00218979 (ISSN) Hosseini, Z. S ; Shasti, M ; Ramezani Sani, S ; Mortezaali, A ; Sharif University of Technology
    American Institute of Physics Inc 
    Abstract
    Titanium oxide (TiO2)-based photodetectors were fabricated using a thermal oxidation technique. The effect of two different annealing temperatures on morphology, structure, and I-V characteristics has been investigated. TiO2/Si heterostructure exhibited diode-like rectifying I-V behavior both in dark and under illumination. Dependence in photoresponse on annealing temperature was observed that was related to effective surface area of quasi-one-dimensional TiO2 nanostructures. Fabricated TiO2/Si diodes in 850 °C as the lower annealing temperature showed higher responsivity and sensitivity compared with grown ones in 950 °C (R850 °C/R950 °C ∼ 5 and S850 °C/S950 °C ∼ 1.6). Rather good... 

    A low cost, efficient method for chip fabrication in cell analysis

    , Article 2016 23rd Iranian Conference on Biomedical Engineering and 2016 1st International Iranian Conference on Biomedical Engineering, ICBME 2016, 23 November 2016 through 25 November 2016 ; 2017 , Pages 93-96 ; 9781509034529 (ISBN) Rahmani, A ; Mohammadi, A ; Kalhor, H ; Sharif University of Technology
    Abstract
    in recent decades, DEP due to its high efficiency has been exploited widely in separation and manipulation of bioparticles. In the present work a simple, low-cost, and efficient procedure for fabrication of microfluidic chips applied in medicine and biochemistry has been presented. In this method, electrodes are not in direct contact with biological samples which results in elimination of conventional systems' cons. Efficacy of the designed system has been evaluated by injecting samples containing yeast and Ecoli cells into the system and analyzing their trajectory. Experimental results demonstrate that precise adjustment of voltage and frequency can lead to the desired separation in this... 

    Decolorization of denim fabrics with cold plasmas in the presence of magnetic fields

    , Article Plasma Processes and Polymers ; Volume 3, Issue 3 , 2006 , Pages 316-321 ; 16128850 (ISSN) Ghoranneviss, M ; Moazzenchi, B ; Shahidi, S ; Anvari, A ; Rashidi, A ; Sharif University of Technology
    2006
    Abstract
    Denim jeans have consistently been fashionable around the world. This fabric inspired strong opinions from historians, teenagers, and movie stars, and has acquired different styles throughout the years. Most jeans today are stonewashed; this technique first become popular in 1970. Now, in addition to pumice stones, enzymes are used on the cotton fabrics to create the stonewashed look. Nowadays, plasma treatment is a cost-effective and environment-friendly process which is able to modify the properties of the fabric surface in order to achieve this effect. Plasma surface treatment changes the properties of the fabric up to a limited depth (several molecular layers), leaving the bulk... 

    A new approach to model sensitivity of graphene-based gas sensors

    , Article Semiconductor Science and Technology ; Volume 30, Issue 4 , March , 2015 ; 02681242 (ISSN) Ghadiry, M ; Ismail, R ; Naraghi, B ; Taheri Abed, S ; Kavosi, D ; Fotovatikhah, F ; Sharif University of Technology
    Institute of Physics Publishing  2015
    Abstract
    Carbon-based sensors are attractive because of their excellent sensing capability. In this paper, we propose a new approach to analytically model the sensitivity of these devices based on graphene. The model relies on the surface potential and current of the device. For the first time, we included ionization in the modelling and examined the importance of this effect. In order to validate the model, the results are compared with experimental data from a fabricated device  

    An IPMC-made deformable-ring-like robot

    , Article Smart Materials and Structures ; Volume 21, Issue 6 , June , 2012 ; 09641726 (ISSN) Firouzeh, A ; Ozmaeian, M ; Alasty, A ; Iraji Zad, A ; Sharif University of Technology
    Abstract
    In this paper application of ionic polymermetal composite (IPMC) as an actuator in a deformable circular robot is studied. Large bending deformation induced by small stimulating voltage, low stiffness and the sensing characteristics that in future work can be used in feedback control make IPMC a good choice for such an application. Here, first a model for IPMC is proposed that can be used in simulating different arrangements of actuators. The parameters of the model are determined using results of blocked force and free displacement tests. Using this model, potentials of an IPMC-made ring-like robot in passing obstacles and the effect of the number of segments on the rings performance are... 

    Steganography in textiles

    , Article 4th International Symposium on Information Assurance and Security, IAS 2008, Napoli, 8 September 2008 through 10 September 2008 ; 2008 , Pages 56-61 ; 9780769533247 (ISBN) Shirali Shahreza, S ; Shirali Shahreza, M ; Sharif University of Technology
    2008
    Abstract
    Covert exchange of information has been long a significant and highlighted affair. Numerous methods have been devised for the matter of which steganography is a popular one. Already applied in the past, the method has been massive used following the invention of computer. This paper discusses a new application of steganography in textiles in which information is hidden in the images on the clothes. In this way, information is first hidden by computer in images by a special method. Then the provided images are printed on clothes. The related information is extracted after scanning the images by relevant programs. © 2008 IEEE  

    Effect of vortex flow on heat transfer to combustion chamber wall

    , Article Journal of Engineering for Gas Turbines and Power ; Volume 129, Issue 2 , 2007 , Pages 622-624 ; 07424795 (ISSN) Ghafourian, A ; Saidi, M. H ; Jahangirian, S ; Abarham, M ; Sharif University of Technology
    2007
    Abstract
    A new experimental facility was designed, fabricated, and tested to model and study the effect of bidirectional swirl flow on the rate of heat transfer to combustion chamber walls. Reduction of this heat transfer can result in time and cost of design and fabrication methods of combustion chambers. The experimental study was performed using propane and air with oxygen as fuel and oxidizer respectively. For similar flow rates, in cases where bidirectional flow was present, wall temperature reductions of up to 70% were observed. In cases where only some of the oxidizer was injected from the chamber end to generate the bidirectional swirl flow, the lowest wall temperature existed. This can be...