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magnetic-materials
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Proceedings: Third International Conference on Magnetic and Superconducting Materials (MSM '03), Monastir, Tunisia, 1-4 September 2003
, Book ; Akhavan, M.(Mohammad)
Wiley-VCH
2004
Proceedings of the first Regional Conference on Magnetic and Superconducting Materials (MSM-99); Tehran, Iran, 27-30 Sept. 1999
, Book ; Akhavan, M ; Jensen, J ; Kitazawa, K
World Scientific
2000
Microinjection moulding of 316L/17-4PH and 316L/Fe powders for fabrication of magnetic-nonmagnetic bimetals
, Article Journal of Materials Processing Technology ; Volume 200, Issue 1-3 , 2008 , Pages 259-264 ; 09240136 (ISSN) ; Rota, A ; Simchi, A ; Sharif University of Technology
2008
Abstract
In the investigations presented here, the feasibility of producing magnetic-nonmagnetic bimetals made of 316L/17-4PH and 316L/Fe powders by micro-metal injection moulding process (μ-MIM) was studied. In order to achieve sound replication of small specimens with dimensions less than 1 mm, very fine powders with mean particle sizes in the range of 3-7 μm were used. A wax-polymer binder system specially designed for micro-moulding was used to make up the feedstock. The isothermal and non-isothermal sintering behaviour of the moulded components was evaluated under hydrogen atmosphere. The effect of powder-binder-ratio of the feedstock, master alloy addition, and sintering conditions on the...
Interplay of magnetism and superconductivity
, Article Physica Status Solidi (A) Applications and Materials Science ; Volume 203, Issue 11 , 2006 , Pages 2956-2961 ; 18626300 (ISSN) ; Sharif University of Technology
2006
Abstract
After about two decades of intense research since the discovery of high-temperature superconductivity (HTSC) in cuprates, although many aspects of the physics and chemistry of these cuprate superconductors are now well understood, the underlying pairing mechanism remains elusive. Magnetism and superconductivity are usually thought as incompatible, but in number of special materials including HTSCs these two mutually excluding mechanisms are found to coexist. The presence in a system of superconductivity and magnetism, gives rise to a large number of interesting phenomenon. This article provides perspective on recent developments and their implications for our understanding of the interplay...
Production of (Nd,MM)2(Fe,Co,Ni)14B-type sintered magnets using a binary powder blending technique
, Article Journal of Alloys and Compounds, Lausanne ; Volume 298, Issue 1-2 , 2000 , Pages 319-323 ; 09258388 (ISSN) ; Kianvash, A ; Seyyed Reihani, M ; Yoozbashi Zadeh, H ; Sharif University of Technology
Elsevier Science S.A
2000
Abstract
The anisotropic (Nd,MM)2(Fe,Co,Ni)14B-type magnets were produced using the binary alloy sintering method (MM denotes a Misch-metal). The composition of the master alloy was close to stoichiometric Nd2Fe14B compound, while that of the sintering aid was MM38.2Co46.4Ni15.4. The microstructures of sintered magnets were investigated using a scanning electron microscope (SEM) equipped with an energy dispersive X-ray detector (EDX). X-ray diffractometry (XRD) was also employed for phase analysis. The optimum magnetic properties were obtained for a composition of Nd11.9MM2.9Fe73.9Co3.3Ni1.1B6.9 made of 90 wt.% master alloy and 10 wt.% sintering aid. The two main phases, i.e. the (RE)2(TM)14B phase...
Excitation of Magnetic Surface Waves for Anomalous Reflection and Transmission of Electromagnetic Waves
, M.Sc. Thesis Sharif University of Technology ; Rejaei, Behzad (Supervisor)
Abstract
The phenomenon of extraordinary transmission of electromagnetic waves through arrays of small holesin metallic plates has attracted the attention of many researchers in the past decade.This behavior may be utilized to fabricate extremely narrowband microwave or optical filters and near-field sensing devices where the sub-millimeter hole can act like a probe. Despite almost ten years of continuous research, however, the uncertainty regarding the mechanisms underlying this phenomenon somewhat persists. Different theories concerning the origin of such behaviors, including surface waves, diffraction of electromagnetic waves, and waveguide phenomenon inside holes and slits have been proposed. But...
The effects of Misch-Metal oxide addition on magnetic properties and crystal structure of Sr1-xMMxFe12O19 ferrite
, Article Journal of Alloys and Compounds ; Volume 448, Issue 1-2 , 2008 , Pages 284-286 ; 09258388 (ISSN) ; Naghibolashraphy, N ; Sharif University of Technology
2008
Abstract
The effects of Misch-Metal (MM) oxide addition on magnetic properties, crystal structure and microstructure of the M-type strontium ferrite have been studied. By MM substitution of Sr a significant increase in intrinsic coercivity and a slight decrease in remanence was observed. The highest value of energy product was obtained at 4 wt.% MM addition. By calculating the lattice constants of 4 and 8 wt.% MM added specimens, it was found that the length of c-axis decreases by 4 wt.% MM addition and then undergoes a considerable increase at 8 wt.%, while the a-axis increases monotonously. The SEM observations revealed that the migration of MM oxides to the grain boundaries could be the major...
Structural, magnetic, and optical properties of zinc-and copper-substituted nickel ferrite nanocrystals
, Article Journal of Superconductivity and Novel Magnetism ; Volume 25, Issue 7 , 2012 , Pages 2443-2455 ; 15571939 (ISSN) ; Daadmehr, V ; Rezakhani, A. T ; Akbarnejad, R. H ; Gholipour, S ; Sharif University of Technology
Springer
2012
Abstract
Ferrite nanocrystals are an interesting material due to their rich physical properties. Here we add nonmagnetic dopants Zn and Cu to nickel ferrite nanocrystals, Ni1-xMxFe2O4 (0 ≤ x ≤ 1, M = Cu, Zn), and study how relevant properties of the samples are modified accordingly. Basically, these dopings cause a rearrangement of Fe +3 ions into the two preexisting octahedral and tetrahedral sites. In fact, this, we show, induces pertinent magnetic properties of the doped samples. In the case of the Cu-doping, the Jahn-Teller effect also emerges, which we identify through the Fourier Transform Infra-Red Spectroscopy of the samples. Moreover, we show an increase in the lattice parameters of the...
Analysis and Test of Magnetic Behavior of Special Materials and its Nano Scaling Behavior
, M.Sc. Thesis Sharif University of Technology ; Rashidian, Bijan (Supervisor)
Abstract
In the first part of this thesis, limitations on magnetic field distribution are studied. After that methods of creating high gradient magnetic field and limitations on it is discussed. In the second part, magnetic properties of materials and the effect of particle shape and size on these properties are studied. In this part a comprehensive analysis on demagnetizing field inside magnetic bodies is also conducted and its dependence on material susceptibility and shape is discussed. At the end of this part the effect of particle shape and size on its hysteresis loop is demonstrated theoretically, practically and by computer simulation. In order to ...
Perfect state transfer on spin-1 chains
, Article Quantum Information Processing ; Vol. 13, issue. 3 , 2014 , pp. 601-614 ; ISSN: 15700755 ; Karimipour, V ; Sharif University of Technology
Abstract
We show that networks of spin-1 particles connected in a special geometry and subject to Affleck-Kennedy-Lieb-Tasaki (AKLT) interaction are capable of perfectly transferring states of particles (qubits and qutrits) if we also allow a global control of the network in predetermined time intervals. The geometry can be one, two, and three dimensional. The strengths of the couplings have the same modulus, and only their signs differ on various bonds. Any particle which is routed in the network acquires relative phase shifts which can be corrected after it is extracted from the network. An advantage of this protocol is that one can route more than one particle through the network simultaneously....
Effect of annealing on soft magnetic behavior of nanostructured (Fe 0.5Co0.5)73.5Si13.5B 9Nb3Cu1 ribbons
, Article Journal of Alloys and Compounds ; Vol. 582, issue , 2014 , pp. 79-82 ; Hosseini, H. R. M ; Davami, P ; Gjoka, M ; Loizos, G ; Aashuri, H ; Sharif University of Technology
Abstract
The effects of relaxation and nanocrystallization on magnetic properties of (Fe0.5Co0.5)73.5Si13.5B 9Nb3Cu1 ribbons have been investigated. Ribbons were melt-spun at wheel speed of 38 m/s and then annealed at different temperatures. The results indicated that the relaxation processes shift the Curie temperature of amorphous phase to the higher temperatures. It was also found that through crystallization phenomena the saturation magnetization increases due to the super-exchange between Fe and Co atoms in the crystalline phase. A slight variation in magnetization was observed at ~700 °lC during heating due to the ordering transition in FeCo system. At early stage of crystalline phase...
Three-particle deterministic secure and high bit-rate direct quantum communication protocol
, Article Quantum Information Processing ; Volume 12, Issue 7 , 2013 , Pages 2441-2451 ; 15700755 (ISSN) ; Bahrampour, A ; Zandi, M. H ; Sharif University of Technology
2013
Abstract
A scheme for deterministic secure and high bit-rate direct communication without resorting to a distinct control interval is proposed. It utilizes three entangled qubits, and presents higher bit transfer rate of information and higher security. The security of protocol is asserted by introducing a security control for each transferred bit. The protocol is investigated for a class of individual attacks and it is explicitly showed that the protocol has a high security even in the presence of channel loss
Facile fabrication and characterization of amino-functionalized Fe 3O4 cluster@SiO2 core/shell nanocomposite spheres
, Article Materials Research Bulletin ; Volume 48, Issue 6 , 2013 , Pages 2023-2028 ; 00255408 (ISSN) ; Kazemeini, M ; Arpanaei, A ; Sharif University of Technology
2013
Abstract
We developed a modified straightforward method for the fabrication of uniformly sized silica-coated magnetite clusters core/shell type nanocomposite particles. Proposed simple one-step processing method permits quick production of materials in high yield. The structural, surface, and magnetic characteristics of the nanocomposite particles were investigated by transmission electron microscopy (TEM), scanning electron microscope (SEM), powder X-ray diffraction (XRD), vibrating sample magnetometer (VSM), and Fourier-transform infrared (FTIR). The sphere-shaped particles almost have the average diameter of 120 nm, with a magnetic cluster core of 80 ± 15 nm, and a silica shell of 25 ± 10 nm...
Iron-borosilicate soft magnetic composites: the correlation between processing parameters and magnetic properties for high frequency applications
, Article Journal of Magnetism and Magnetic Materials ; Volume 429 , 2017 , Pages 241-250 ; 03048853 (ISSN) ; Madaah Hosseini, H .R ; Seyed Reihani, S. M ; Sharif University of Technology
Elsevier B.V
2017
Abstract
Iron-borosilicate soft magnetic composites are suitable magnetic materials for high temperature and high frequency applications. In this research two different techniques have been applied to fabricate these composites: uniaxial pressing following by sintering and spark plasma sintering. Different processing parameters including the content of borosilicate, the amount of compaction pressure and the size of iron particles have been evaluated through the study of microstructure and magnetic properties. The microstructural observations showed that the borosilicate is distributed on the iron grain boundaries enhancing the resistivity and causing the loss of eddy currents. Increasing the...
A Fabrication Method of Neutrally-buoyant Magnetic Micro-robot to Improve Its Motion Control
, M.Sc. Thesis Sharif University of Technology ; Nejat Pishkenari, Hossein (Supervisor)
Abstract
Micro-robotics is one of the currently emerging technologies which has attracted attentions for its probable applications in different fields including biotechnology, diagnosis and treatment in medical engineering as well as general studies in micro-scale science and engineering. Magnetic micro-robotics is considered as the most promising group, primarily due to the biocompatibility of magnetic fields and advances in electronic circuits to produce and control such fields. One critical point in utilizing these robots is their high density in comparison with the working fluid and their tendency to sink. In this thesis, a method to fabricate buoyant magnetic robots has been proposed based on...
Zinc ferrite spinel-graphene in magneto-photothermal therapy of cancer
, Article Journal of Materials Chemistry B ; Vol. 2, Issue. 21 , 2014 , p. 3306-3314 ; Meidanchi, A ; Ghaderi, E ; Khoei, S ; Sharif University of Technology
Abstract
A magneto-photothermal therapy for cancer (in vitro photothermal therapy of prostate cancer cells and in vivo photothermal therapy of human glioblastoma tumors in the presence of an external magnetic field) was developed using superparamagnetic zinc ferrite spinel (ZnFe2O4)-reduced graphene oxide (rGO) nanostructures (with various graphene contents). In vitro application of a low concentration (10 μg mL-1) of the ZnFe 2O4-rGO (20 wt%) nanostructures under a short time period (∼1 min) of near-infrared (NIR) irradiation (with a laser power of 7.5 W cm-2) resulted in an excellent destruction of the prostate cancer cells, in the presence of a magnetic field (∼1 Tesla) used for localizing the...
Diffraction influence on the field of view and resolution of three-dimensional integral imaging
, Article IEEE/OSA Journal of Display Technology ; Vol. 10, issue. 7 , 2014 , pp. 553-559 ; Kavehvash, Z ; Mehrany K ; Sharif University of Technology
Abstract
The influence of the diffraction limit on the field of view of three-dimensional integral imaging (InI) systems is estimated by calculating the resolution of the InI system along arbitrarily tilted directions. The deteriorating effects of diffraction on the resolution are quantified in this manner. Two different three-dimensional scenes are recorded by real/virtual and focused imaging modes. The recorded scenes are reconstructed at different tilted planes and the obtained results for the resolution and field of view of the system are verified. It is shown that the diffraction effects severely affect the resolution of InI in the real/virtual mode when the tilted angle of viewing is increased....
A novel rotor configuration for brushless doubly-fed induction generators
, Article IET Electric Power Applications ; Volume 7, Issue 2 , 2013 , Pages 106-115 ; 17518660 (ISSN) ; Jandaghi, B ; Oraee, H ; Sharif University of Technology
2013
Abstract
Brushless Doubly-Fed Induction Generator has attractive features to be the first choice in next generation of wind generators. However, its efficiency and power-to-weight ratio are slightly lower in comparison to induction machine with the same rating. Considerable part of these imperfections arises from the rotor design, which produces magnetic field with considerable undesirable spatial harmonics. This paper proposes a novel rotor configuration to reduce spatial harmonic distortion of air-gap magnetic field as well as improving some drawbacks of the conventional structure, including unequal magnitudes of rotor bar currents, teeth saturation at low average air gap magnetic fields, high core...
Excitation shifting: A general low-cost solution for eliminating ultra-low-frequency torque ripple in switched reluctance machines
, Article IEEE Transactions on Magnetics ; Volume 49, Issue 9 , Sept , 2013 , Pages 5135-5149 ; 00189464 (ISSN) ; Davoudi, A ; Kaboli, S ; Edrington, C. S ; Sharif University of Technology
2013
Abstract
Switched reluctance machines (SRMs) suffer from ultra-low-frequency torque ripple in single pulse mode. This ripple is the result of an imbalance in phase currents, when multiphase excitation occurs. This paper investigates the origin of this imbalance and identifies the imbalanced phase. Excitation shifting strategy, which delays excitation of the imbalanced phase, is then proposed. The delay angle adjusts current amplitude in the imbalanced phase to attain a perfect balance between all phases. The excitation shifting strategy is a general solution, which is applicable to both three-phase and four-phase machines. In addition, the proposed method can be implemented by a much simpler drive...
HAFTA: Highly available fault-tolerant architecture to protect SRAM-based reconfigurable devices against multiple bit upsets
, Article IEEE Transactions on Device and Materials Reliability ; Volume 13, Issue 1 , November , 2013 , Pages 203-212 ; 15304388 (ISSN) ; Miremadi, S. G ; Asadi, H ; Fazeli, M ; Sharif University of Technology
2013
Abstract
Despite widespread use of SRAM-based reconfigurable devices (SRDs) in mainstream applications, their usage has been very limited in enterprise and safety-critical applications due to SRAM susceptibility to soft errors. Previous mitigation techniques to protect SRDs impose significant area and power overheads. Additionally, they suffer from susceptibility of configuration bits to multiple bit upsets (MBUs). In this paper, we present a highly available fault-tolerant architecture to protect SRD-based designs against MBUs in both configuration and user bits. In the proposed architecture, the entire design is duplicated with respect to the relative locations of logic blocks within the SRD and...