mojtaba ranjbar - Academia.edu (original) (raw)
Papers by mojtaba ranjbar
Journal of Shahid Sadoughi University of Medical Sciences, 2021
Introduction: The spread of drug-resistant pathogenic strains and the increase of free radicals i... more Introduction: The spread of drug-resistant pathogenic strains and the increase of free radicals in food sources are major health problems worldwide. The side effects of chemical drugs have led the researchers to use natural products. In this study, the antimicrobial and antioxidant effects of leaf extract of Lythrum Salicaria have been investigated. Methods: This research was a basic experimental study. The aqueous extract of Lythrum Salicaria leaf was prepared by maceration method. Antimicrobial effects of the extract were evaluated by disk diffusion method. The antioxidant properties of extract were determined by DPPH and iron reducing power methods. In addition, the amounts of phenol, flavonoid and flavonol were assayed by Folin-ciocalteu and Aluminum chloride methods, respectively. Data were compared by analysis of variance (ANOVA) using SPSS version 16 software. Results: All of the studied strains were sensitive to the aqueous extract of Lythrum Salicaria leaf except E. coli. T...
Journal of Shahid Sadoughi University of Medical Sciences, 2021
Introduction: The spread of drug-resistant pathogenic strains and the increase of free radicals i... more Introduction: The spread of drug-resistant pathogenic strains and the increase of free radicals in food sources are major health problems worldwide. The side effects of chemical drugs have led the researchers to use natural products. In this study, the antimicrobial and antioxidant effects of leaf extract of Lythrum Salicaria have been investigated. Methods: This research was a basic experimental study. The aqueous extract of Lythrum Salicaria leaf was prepared by maceration method. Antimicrobial effects of the extract were evaluated by disk diffusion method. The antioxidant properties of extract were determined by DPPH and iron reducing power methods. In addition, the amounts of phenol, flavonoid and flavonol were assayed by Folin-ciocalteu and Aluminum chloride methods, respectively. Data were compared by analysis of variance (ANOVA) using SPSS version 16 software. Results: All of the studied strains were sensitive to the aqueous extract of Lythrum Salicaria leaf except E. coli. T...
Journal of Shahid Sadoughi University of Medical Sciences, 2021
Introduction: The spread of drug-resistant pathogenic strains and the increase of free radicals i... more Introduction: The spread of drug-resistant pathogenic strains and the increase of free radicals in food sources are major health problems worldwide. The side effects of chemical drugs have led the researchers to use natural products. In this study, the antimicrobial and antioxidant effects of leaf extract of Lythrum Salicaria have been investigated. Methods: This research was a basic experimental study. The aqueous extract of Lythrum Salicaria leaf was prepared by maceration method. Antimicrobial effects of the extract were evaluated by disk diffusion method. The antioxidant properties of extract were determined by DPPH and iron reducing power methods. In addition, the amounts of phenol, flavonoid and flavonol were assayed by Folin-ciocalteu and Aluminum chloride methods, respectively. Data were compared by analysis of variance (ANOVA) using SPSS version 16 software. Results: All of the studied strains were sensitive to the aqueous extract of Lythrum Salicaria leaf except E. coli. T...
In this paper, we discuss a numerical method based on a p-stage Runge-Kutta method. Trapezoid met... more In this paper, we discuss a numerical method based on a p-stage Runge-Kutta method. Trapezoid method is obtained by p-stage Runge-Kutta method. convergence and stability of Trapezoid method is also proved in detail. In addition, this method is illustrated by solving one fuzzy Cauchy problem.
Glioblastoma (GB) is a common primary malignancy of the central nervous system, and one of the hi... more Glioblastoma (GB) is a common primary malignancy of the central nervous system, and one of the highly lethal brain tumors. GB cells can promote therapeutic resistance and tumor angiogenesis. The CD171 is an adhesion molecule in neuronal cells that is expressed in glioma cells; it is a regulator of the brain development. CD171 is one of the immunoglobulin-like CAMs (cell adhesion molecules) families that can be associated with prognosis in a variety of human tumors. The multi-epitope peptide vaccines are based on synthetic peptides with a combination of both B-cell epitopes and T-cell epitopes, which can induce specific humoral or cellular immune responses. In the present study, several immune-informatics tools were used for analyzing the CD171 sequence and studying the important characteristics of a designed vaccine. The results included the prediction and validation of the secondary and tertiary structure, physicochemical properties, solubility, conservancy, toxicity as well as ant...
In this article, we introduce a new variable shape parameter is called symmetric variable shape p... more In this article, we introduce a new variable shape parameter is called symmetric variable shape parameter (SVSP) for Gaussian radial basis functions (GRBFs). The GRBF has the shape parameter ccc, which plays an important role in the accuracy of the approximation. In this work, we will use it to interpolate functions and solve linear boundary value problems (LBVP). Some numerical experiments are presented to show accuracy and robustness of the GRBF with SVSP strategy. These results have the best accuracy for the one- and two-dimensional interpolations and LBVP. Besides, the numerical results show that the SVSP for GRBF often outperforms constant shape parameter strategy.
Cumin, Cuminum cyminum L., is the king of spices with a plethora of natural compounds with pharma... more Cumin, Cuminum cyminum L., is the king of spices with a plethora of natural compounds with pharmacological features. Drought stress is a well-known factor that influences the production of some metabolites. We studied the impact of drought stress on gene expression and metabolite content in flower and leaf tissue organs of two ecotypes, Taybad and Ardakan populations. Plants were imposed into three water level conditions, control, moderate, and severe water deficit. Concerning the results, the expression of Limonene synthase in flower organ of the Ardakan genotype increased 2.2 times under 50% of field capacity, whereas, the expression of Flavone synthase in leaf tissue of the Ardakan ecotype, was the highest in this level of stress. Moreover, the majority of detected terpenoids were β-Acoradiene and γ-Terpinene in leaf and flower organs, respectively. Altogether, the monoterpenes content was decreased in both ecotypes, but sesquiterpenes increased only in the Ardakan population. Kn...
European Journal of Pharmacology, 2020
Chitosan-based polymeric nanocarrier has been utilized as a novel drug delivery device in recent ... more Chitosan-based polymeric nanocarrier has been utilized as a novel drug delivery device in recent years due to its prominent role in the treatment of central nervous system disorders. The aim of this study was to investigate the anti-oxidative and anti-inflammatory effects of silymarin-loaded chitosan nanoparticles (SM-CS-NPs) on rat model of global cerebral ischemia/reperfusion (I/R). All rats were randomly distributed into four groups: Control, I/R, SM and SM-CS-NPs. Oral administration of SM and SM-CS-NPs was started 14 days prior to bilateral common carotid artery occlusion (BCCAO). Depressive-like behaviors, infarct volume, some oxidative stress markers and inflammatory factors were assessed after induction of I/R. SM-CS-NPs pretreatment significantly ameliorated depressive-like behaviors and infarct volume after I/R. SM-CS-NPs also significantly decreased the levels of malondialdehyde (MDA), and expression of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), and significantly increased the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GRx), and glutathione (GSH) levels in I/R brain. The current study demonstrated that SM-CS-NPs pretreatment effectively prevents oxidative and inflammatory damage in the brain caused by I/R, and it can be considered as a useful pretreatment to attenuate the negative effects of I/R.
chemistry of plant raw material, 2017
Artemisia scoparia Waldst.et Kit. is an annual or biennial plant, widely spread on Transbaikal Te... more Artemisia scoparia Waldst.et Kit. is an annual or biennial plant, widely spread on Transbaikal Territory. We have attempted to identify the leading factor affecting on the composition of essential oil in this article. Raw materials were collected during field works in 2014-2016 on the territory of Buryatia and on Transbaikal Territory. Essential oil was obtained by hydrodistillation method from air-dried raw materials. The chemical composition of the oil was analyzed by chromatography-mass spectrometry. According to the composition of the components the studied oils referred to a chemotype containing monoterpene and sesquiterpene compounds as the main components. β-Myrcene, limonene, α- and β-pinenes, α- and β-farnesenes, caryophyllene, α-copaene, spathulenol were identified almost in all samples except one, and p-cymol, γ-terpinene, humulene, caryophyllene oxide were found in most of them.The variety of identified components of oils was associated with the secondary transformation ...
Communications Physics, 2019
Graphene is a promising material for sensing magnetic fields via the Hall effect due to its atomi... more Graphene is a promising material for sensing magnetic fields via the Hall effect due to its atomic-scale thickness, ultra-high carrier mobilities and low cost compared to conventional semiconductor sensors. Because of its Dirac band structure, graphene sensors differ from semiconductor sensors in that both electrons and holes participate in the carrier transport. This two-channel transport complicates the sensor operation and causes performance tradeoffs that demand careful examination. Here, we examine the operation of graphene sensors operated near the charge neutrality point (CNP) where two-channel transport prevails. We find that, while the largest magnetoresistance occurs exactly at the CNP, the maximum realizable Hall sensitivities occur away from the CNP and depend on linearity constraints and power limitations. In particular, a more stringent linearity constraint reduces the realizable sensitivities for mobilities above a critical value µ c , which scales with magnetic field.
Communications Physics, 2019
Graphene is a promising material for sensing magnetic fields via the Hall effect due to its atomi... more Graphene is a promising material for sensing magnetic fields via the Hall effect due to its atomic-scale thickness, ultra-high carrier mobilities and low cost compared to conventional semiconductor sensors. Because of its Dirac band structure, graphene sensors differ from semiconductor sensors in that both electrons and holes participate in the carrier transport. This two-channel transport complicates the sensor operation and causes performance tradeoffs that demand careful examination. Here, we examine the operation of graphene sensors operated near the charge neutrality point (CNP) where two-channel transport prevails. We find that, while the largest magnetoresistance occurs exactly at the CNP, the maximum realizable Hall sensitivities occur away from the CNP and depend on linearity constraints and power limitations. In particular, a more stringent linearity constraint reduces the realizable sensitivities for mobilities above a critical value µ c , which scales with magnetic field.
Inverse Problems in Science and Engineering, 2018
This work introduces a new numerical solution to the inverse parabolic problem with source contro... more This work introduces a new numerical solution to the inverse parabolic problem with source control parameter that has important applications in large fields of applied science. We expand the approximate solution of the inverse problem in terms of shifted Chebyshev polynomials in time and radial basis functions with symmetric variable shape parameter in space, with unknown coefficients. Unknown coefficient matrix determined using the collocation technique. Sample results show that the proposed method is very accurate. Moreover, the proposed method is compared with two other methods, fourth-order compact difference scheme and method of lines. Finally, we examine the stability of our method for the case where there is additive noise in input data.
Journal of Magnetism and Magnetic Materials, 2017
We present a study of perpendicular magnetic anisotropy in [Co/Ni(t)/Co/Pt] ×8 multilayers for us... more We present a study of perpendicular magnetic anisotropy in [Co/Ni(t)/Co/Pt] ×8 multilayers for use as free layers in magnetic tunnel junctions (MTJ) and spin valves. The thickness t of the Ni sub-layer was varied and the resulting magnetic properties were compared with (Co/Ni) and (Co/Pt) multilayers with the same number of repeats. As determined from magnetic force microscopy and magnetometry measurements, all multilayers exhibited a perpendicular magnetic anisotropy with an increase of saturation magnetization with thickness t. From the temperature dependence of the magnetization, well described by a Bloch law, we find that the spin-wave stiffness constant of the [Co/Ni(t)/Co/Pt] ×8 multilayers is larger compared to (Co/Ni) multilayers. These multilayers could be the basis for spintronic devices where the reduction of total Pt content could help to reduce the damping constant while keeping the magnetic anisotropy energy relatively high. These are conflicting requirements needed for high performance magnetic memory devices. Highlights • New material based on (Co/Ni/Co/Pt) multilayer with perpendicular magnetic anisotropy is investigated. • The magnetic properties were investigated in (Co/Ni/Co/Pt) with different Ni thickness. • Micromagnetic simulation was carried out to reproduce magnetic force microscopy images. • From magnetometry measurements, micromagnetic simulation and temperature dependence of intrinsic properties (saturation magnetization and anisotropy energy), Block constant and spin wave stiffness were determined for each sample.
Mathematics, 2018
It is well known that the Black-Scholes model is used to establish the behavior of the option pri... more It is well known that the Black-Scholes model is used to establish the behavior of the option pricing in the financial market. In this paper, we propose the modified version of Black-Scholes model with two assets based on the Liouville-Caputo fractional derivative. The analytical solution of the proposed model is investigated by the Laplace transform homotopy perturbation method.
Journal of Magnetism and Magnetic Materials, 2017
We propose and demonstrate a technique for magnetic microstructure imaging via their interaction ... more We propose and demonstrate a technique for magnetic microstructure imaging via their interaction with propagating spin waves. In this approach, the object of interest is placed on top of a magnetic testbed made of material with low spin wave damping. There are micro-antennas incorporated in the testbed. Two of these antennas are used for spin wave excitation while another one is used for the detecting of inductive voltage produced by the interfering spin waves. The measurements are repeated for different phase differences between the spin wave generating antennas which is equivalent to changing the angle of illumination. The collected data appear as a 3D plotthe holographic image of the object. We present experimental data showing magnonic holographic images of a low-coercivity Si/Co sample, a high-coercivity sample made of SrFe 12 O 19 and a diamagnetic copper sample. We also present images of the three samples consisting of a different amount of SrFe 12 O 19 powder. The imaging was accomplished on a Y 3 Fe 2 (FeO 4) 3 testbed at room temperature. The obtained data reveal the unique magnonic signatures of the objects. Experimental data is complemented by the results of numerical modeling, which qualitatively explain the characteristic features of the images. Potentially, magnonic holographic imaging may complement existing techniques and be utilized for non-destructive in-situ magnetic object characterization. The fundamental physical limits of this approach are also discussed.
Journal of Applied Physics, 2016
Determining the prime factors of a given number N is a problem, which requires superpolynomial ti... more Determining the prime factors of a given number N is a problem, which requires superpolynomial time for conventional digital computers. A polynomial-time algorithm was invented by P. Shor for quantum computers. However, the realization of quantum computers is associated with significant technological challenges in achieving and preserving quantum entanglement. Prime factorization can be also solved by using classical wave interference without quantum entanglement. In this work, we present experimental data showing prime factorization by utilizing spin wave interference. The prime factorization includes three major steps. First, general type computer calculates the sequence of numbers m k mod(N), where N is the number to be factorized, m is a randomly chosen positive integer, and k=0,1,2,3,4,5,6 ... Next, the period of calculated sequence r is determined by exploiting spin wave interference. Finally, the general type
Chemical characterization and antioxidant activity of sulfated polysaccharides from sp, (2017), d... more Chemical characterization and antioxidant activity of sulfated polysaccharides from sp, (2017), doi: Navicula Food Hydrocolloids 10.1016/j.foodhyd.2017.08.002 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Chemical characterization and antioxidant activity of sulfated polysaccharides from Navicula sp.
IEEE Magnetics Letters, 2016
NiFe-Cu-Co trilayer nano-contact spin-torque oscillators (NC-STOs) fabricated on an yttrium-iron ... more NiFe-Cu-Co trilayer nano-contact spin-torque oscillators (NC-STOs) fabricated on an yttrium-iron garnet (YIG) film were studied in two different modes. In passive mode, i.e., without auto-oscillations, the NC-STOs both excite and detect spin waves (SW) in the YIG film. In active mode, i.e., in the presence of auto-oscillations, significant changes appear in the NC-STO spectrum when its frequency approaches that of the SWs excited in the YIG. These results demonstrate strong coupling between NC-STOs and SWs in YIG and open new possibilities of (1) pure spin-current generation in YIG by NC-STOs, (2) mutual locking of a number of NC-STOs through SWs in YIG, and (3) improvement of NC-STO spectra through SW feedback in YIG. Index terms-Nanocontact spin-torque oscillators, spin waves, yttrium iron garnet
Turkish Journal of Botany
ABSTRACT
Journal of Applied Physics, 2015
Journal of Shahid Sadoughi University of Medical Sciences, 2021
Introduction: The spread of drug-resistant pathogenic strains and the increase of free radicals i... more Introduction: The spread of drug-resistant pathogenic strains and the increase of free radicals in food sources are major health problems worldwide. The side effects of chemical drugs have led the researchers to use natural products. In this study, the antimicrobial and antioxidant effects of leaf extract of Lythrum Salicaria have been investigated. Methods: This research was a basic experimental study. The aqueous extract of Lythrum Salicaria leaf was prepared by maceration method. Antimicrobial effects of the extract were evaluated by disk diffusion method. The antioxidant properties of extract were determined by DPPH and iron reducing power methods. In addition, the amounts of phenol, flavonoid and flavonol were assayed by Folin-ciocalteu and Aluminum chloride methods, respectively. Data were compared by analysis of variance (ANOVA) using SPSS version 16 software. Results: All of the studied strains were sensitive to the aqueous extract of Lythrum Salicaria leaf except E. coli. T...
Journal of Shahid Sadoughi University of Medical Sciences, 2021
Introduction: The spread of drug-resistant pathogenic strains and the increase of free radicals i... more Introduction: The spread of drug-resistant pathogenic strains and the increase of free radicals in food sources are major health problems worldwide. The side effects of chemical drugs have led the researchers to use natural products. In this study, the antimicrobial and antioxidant effects of leaf extract of Lythrum Salicaria have been investigated. Methods: This research was a basic experimental study. The aqueous extract of Lythrum Salicaria leaf was prepared by maceration method. Antimicrobial effects of the extract were evaluated by disk diffusion method. The antioxidant properties of extract were determined by DPPH and iron reducing power methods. In addition, the amounts of phenol, flavonoid and flavonol were assayed by Folin-ciocalteu and Aluminum chloride methods, respectively. Data were compared by analysis of variance (ANOVA) using SPSS version 16 software. Results: All of the studied strains were sensitive to the aqueous extract of Lythrum Salicaria leaf except E. coli. T...
Journal of Shahid Sadoughi University of Medical Sciences, 2021
Introduction: The spread of drug-resistant pathogenic strains and the increase of free radicals i... more Introduction: The spread of drug-resistant pathogenic strains and the increase of free radicals in food sources are major health problems worldwide. The side effects of chemical drugs have led the researchers to use natural products. In this study, the antimicrobial and antioxidant effects of leaf extract of Lythrum Salicaria have been investigated. Methods: This research was a basic experimental study. The aqueous extract of Lythrum Salicaria leaf was prepared by maceration method. Antimicrobial effects of the extract were evaluated by disk diffusion method. The antioxidant properties of extract were determined by DPPH and iron reducing power methods. In addition, the amounts of phenol, flavonoid and flavonol were assayed by Folin-ciocalteu and Aluminum chloride methods, respectively. Data were compared by analysis of variance (ANOVA) using SPSS version 16 software. Results: All of the studied strains were sensitive to the aqueous extract of Lythrum Salicaria leaf except E. coli. T...
In this paper, we discuss a numerical method based on a p-stage Runge-Kutta method. Trapezoid met... more In this paper, we discuss a numerical method based on a p-stage Runge-Kutta method. Trapezoid method is obtained by p-stage Runge-Kutta method. convergence and stability of Trapezoid method is also proved in detail. In addition, this method is illustrated by solving one fuzzy Cauchy problem.
Glioblastoma (GB) is a common primary malignancy of the central nervous system, and one of the hi... more Glioblastoma (GB) is a common primary malignancy of the central nervous system, and one of the highly lethal brain tumors. GB cells can promote therapeutic resistance and tumor angiogenesis. The CD171 is an adhesion molecule in neuronal cells that is expressed in glioma cells; it is a regulator of the brain development. CD171 is one of the immunoglobulin-like CAMs (cell adhesion molecules) families that can be associated with prognosis in a variety of human tumors. The multi-epitope peptide vaccines are based on synthetic peptides with a combination of both B-cell epitopes and T-cell epitopes, which can induce specific humoral or cellular immune responses. In the present study, several immune-informatics tools were used for analyzing the CD171 sequence and studying the important characteristics of a designed vaccine. The results included the prediction and validation of the secondary and tertiary structure, physicochemical properties, solubility, conservancy, toxicity as well as ant...
In this article, we introduce a new variable shape parameter is called symmetric variable shape p... more In this article, we introduce a new variable shape parameter is called symmetric variable shape parameter (SVSP) for Gaussian radial basis functions (GRBFs). The GRBF has the shape parameter ccc, which plays an important role in the accuracy of the approximation. In this work, we will use it to interpolate functions and solve linear boundary value problems (LBVP). Some numerical experiments are presented to show accuracy and robustness of the GRBF with SVSP strategy. These results have the best accuracy for the one- and two-dimensional interpolations and LBVP. Besides, the numerical results show that the SVSP for GRBF often outperforms constant shape parameter strategy.
Cumin, Cuminum cyminum L., is the king of spices with a plethora of natural compounds with pharma... more Cumin, Cuminum cyminum L., is the king of spices with a plethora of natural compounds with pharmacological features. Drought stress is a well-known factor that influences the production of some metabolites. We studied the impact of drought stress on gene expression and metabolite content in flower and leaf tissue organs of two ecotypes, Taybad and Ardakan populations. Plants were imposed into three water level conditions, control, moderate, and severe water deficit. Concerning the results, the expression of Limonene synthase in flower organ of the Ardakan genotype increased 2.2 times under 50% of field capacity, whereas, the expression of Flavone synthase in leaf tissue of the Ardakan ecotype, was the highest in this level of stress. Moreover, the majority of detected terpenoids were β-Acoradiene and γ-Terpinene in leaf and flower organs, respectively. Altogether, the monoterpenes content was decreased in both ecotypes, but sesquiterpenes increased only in the Ardakan population. Kn...
European Journal of Pharmacology, 2020
Chitosan-based polymeric nanocarrier has been utilized as a novel drug delivery device in recent ... more Chitosan-based polymeric nanocarrier has been utilized as a novel drug delivery device in recent years due to its prominent role in the treatment of central nervous system disorders. The aim of this study was to investigate the anti-oxidative and anti-inflammatory effects of silymarin-loaded chitosan nanoparticles (SM-CS-NPs) on rat model of global cerebral ischemia/reperfusion (I/R). All rats were randomly distributed into four groups: Control, I/R, SM and SM-CS-NPs. Oral administration of SM and SM-CS-NPs was started 14 days prior to bilateral common carotid artery occlusion (BCCAO). Depressive-like behaviors, infarct volume, some oxidative stress markers and inflammatory factors were assessed after induction of I/R. SM-CS-NPs pretreatment significantly ameliorated depressive-like behaviors and infarct volume after I/R. SM-CS-NPs also significantly decreased the levels of malondialdehyde (MDA), and expression of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α), and significantly increased the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GRx), and glutathione (GSH) levels in I/R brain. The current study demonstrated that SM-CS-NPs pretreatment effectively prevents oxidative and inflammatory damage in the brain caused by I/R, and it can be considered as a useful pretreatment to attenuate the negative effects of I/R.
chemistry of plant raw material, 2017
Artemisia scoparia Waldst.et Kit. is an annual or biennial plant, widely spread on Transbaikal Te... more Artemisia scoparia Waldst.et Kit. is an annual or biennial plant, widely spread on Transbaikal Territory. We have attempted to identify the leading factor affecting on the composition of essential oil in this article. Raw materials were collected during field works in 2014-2016 on the territory of Buryatia and on Transbaikal Territory. Essential oil was obtained by hydrodistillation method from air-dried raw materials. The chemical composition of the oil was analyzed by chromatography-mass spectrometry. According to the composition of the components the studied oils referred to a chemotype containing monoterpene and sesquiterpene compounds as the main components. β-Myrcene, limonene, α- and β-pinenes, α- and β-farnesenes, caryophyllene, α-copaene, spathulenol were identified almost in all samples except one, and p-cymol, γ-terpinene, humulene, caryophyllene oxide were found in most of them.The variety of identified components of oils was associated with the secondary transformation ...
Communications Physics, 2019
Graphene is a promising material for sensing magnetic fields via the Hall effect due to its atomi... more Graphene is a promising material for sensing magnetic fields via the Hall effect due to its atomic-scale thickness, ultra-high carrier mobilities and low cost compared to conventional semiconductor sensors. Because of its Dirac band structure, graphene sensors differ from semiconductor sensors in that both electrons and holes participate in the carrier transport. This two-channel transport complicates the sensor operation and causes performance tradeoffs that demand careful examination. Here, we examine the operation of graphene sensors operated near the charge neutrality point (CNP) where two-channel transport prevails. We find that, while the largest magnetoresistance occurs exactly at the CNP, the maximum realizable Hall sensitivities occur away from the CNP and depend on linearity constraints and power limitations. In particular, a more stringent linearity constraint reduces the realizable sensitivities for mobilities above a critical value µ c , which scales with magnetic field.
Communications Physics, 2019
Graphene is a promising material for sensing magnetic fields via the Hall effect due to its atomi... more Graphene is a promising material for sensing magnetic fields via the Hall effect due to its atomic-scale thickness, ultra-high carrier mobilities and low cost compared to conventional semiconductor sensors. Because of its Dirac band structure, graphene sensors differ from semiconductor sensors in that both electrons and holes participate in the carrier transport. This two-channel transport complicates the sensor operation and causes performance tradeoffs that demand careful examination. Here, we examine the operation of graphene sensors operated near the charge neutrality point (CNP) where two-channel transport prevails. We find that, while the largest magnetoresistance occurs exactly at the CNP, the maximum realizable Hall sensitivities occur away from the CNP and depend on linearity constraints and power limitations. In particular, a more stringent linearity constraint reduces the realizable sensitivities for mobilities above a critical value µ c , which scales with magnetic field.
Inverse Problems in Science and Engineering, 2018
This work introduces a new numerical solution to the inverse parabolic problem with source contro... more This work introduces a new numerical solution to the inverse parabolic problem with source control parameter that has important applications in large fields of applied science. We expand the approximate solution of the inverse problem in terms of shifted Chebyshev polynomials in time and radial basis functions with symmetric variable shape parameter in space, with unknown coefficients. Unknown coefficient matrix determined using the collocation technique. Sample results show that the proposed method is very accurate. Moreover, the proposed method is compared with two other methods, fourth-order compact difference scheme and method of lines. Finally, we examine the stability of our method for the case where there is additive noise in input data.
Journal of Magnetism and Magnetic Materials, 2017
We present a study of perpendicular magnetic anisotropy in [Co/Ni(t)/Co/Pt] ×8 multilayers for us... more We present a study of perpendicular magnetic anisotropy in [Co/Ni(t)/Co/Pt] ×8 multilayers for use as free layers in magnetic tunnel junctions (MTJ) and spin valves. The thickness t of the Ni sub-layer was varied and the resulting magnetic properties were compared with (Co/Ni) and (Co/Pt) multilayers with the same number of repeats. As determined from magnetic force microscopy and magnetometry measurements, all multilayers exhibited a perpendicular magnetic anisotropy with an increase of saturation magnetization with thickness t. From the temperature dependence of the magnetization, well described by a Bloch law, we find that the spin-wave stiffness constant of the [Co/Ni(t)/Co/Pt] ×8 multilayers is larger compared to (Co/Ni) multilayers. These multilayers could be the basis for spintronic devices where the reduction of total Pt content could help to reduce the damping constant while keeping the magnetic anisotropy energy relatively high. These are conflicting requirements needed for high performance magnetic memory devices. Highlights • New material based on (Co/Ni/Co/Pt) multilayer with perpendicular magnetic anisotropy is investigated. • The magnetic properties were investigated in (Co/Ni/Co/Pt) with different Ni thickness. • Micromagnetic simulation was carried out to reproduce magnetic force microscopy images. • From magnetometry measurements, micromagnetic simulation and temperature dependence of intrinsic properties (saturation magnetization and anisotropy energy), Block constant and spin wave stiffness were determined for each sample.
Mathematics, 2018
It is well known that the Black-Scholes model is used to establish the behavior of the option pri... more It is well known that the Black-Scholes model is used to establish the behavior of the option pricing in the financial market. In this paper, we propose the modified version of Black-Scholes model with two assets based on the Liouville-Caputo fractional derivative. The analytical solution of the proposed model is investigated by the Laplace transform homotopy perturbation method.
Journal of Magnetism and Magnetic Materials, 2017
We propose and demonstrate a technique for magnetic microstructure imaging via their interaction ... more We propose and demonstrate a technique for magnetic microstructure imaging via their interaction with propagating spin waves. In this approach, the object of interest is placed on top of a magnetic testbed made of material with low spin wave damping. There are micro-antennas incorporated in the testbed. Two of these antennas are used for spin wave excitation while another one is used for the detecting of inductive voltage produced by the interfering spin waves. The measurements are repeated for different phase differences between the spin wave generating antennas which is equivalent to changing the angle of illumination. The collected data appear as a 3D plotthe holographic image of the object. We present experimental data showing magnonic holographic images of a low-coercivity Si/Co sample, a high-coercivity sample made of SrFe 12 O 19 and a diamagnetic copper sample. We also present images of the three samples consisting of a different amount of SrFe 12 O 19 powder. The imaging was accomplished on a Y 3 Fe 2 (FeO 4) 3 testbed at room temperature. The obtained data reveal the unique magnonic signatures of the objects. Experimental data is complemented by the results of numerical modeling, which qualitatively explain the characteristic features of the images. Potentially, magnonic holographic imaging may complement existing techniques and be utilized for non-destructive in-situ magnetic object characterization. The fundamental physical limits of this approach are also discussed.
Journal of Applied Physics, 2016
Determining the prime factors of a given number N is a problem, which requires superpolynomial ti... more Determining the prime factors of a given number N is a problem, which requires superpolynomial time for conventional digital computers. A polynomial-time algorithm was invented by P. Shor for quantum computers. However, the realization of quantum computers is associated with significant technological challenges in achieving and preserving quantum entanglement. Prime factorization can be also solved by using classical wave interference without quantum entanglement. In this work, we present experimental data showing prime factorization by utilizing spin wave interference. The prime factorization includes three major steps. First, general type computer calculates the sequence of numbers m k mod(N), where N is the number to be factorized, m is a randomly chosen positive integer, and k=0,1,2,3,4,5,6 ... Next, the period of calculated sequence r is determined by exploiting spin wave interference. Finally, the general type
Chemical characterization and antioxidant activity of sulfated polysaccharides from sp, (2017), d... more Chemical characterization and antioxidant activity of sulfated polysaccharides from sp, (2017), doi: Navicula Food Hydrocolloids 10.1016/j.foodhyd.2017.08.002 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. Chemical characterization and antioxidant activity of sulfated polysaccharides from Navicula sp.
IEEE Magnetics Letters, 2016
NiFe-Cu-Co trilayer nano-contact spin-torque oscillators (NC-STOs) fabricated on an yttrium-iron ... more NiFe-Cu-Co trilayer nano-contact spin-torque oscillators (NC-STOs) fabricated on an yttrium-iron garnet (YIG) film were studied in two different modes. In passive mode, i.e., without auto-oscillations, the NC-STOs both excite and detect spin waves (SW) in the YIG film. In active mode, i.e., in the presence of auto-oscillations, significant changes appear in the NC-STO spectrum when its frequency approaches that of the SWs excited in the YIG. These results demonstrate strong coupling between NC-STOs and SWs in YIG and open new possibilities of (1) pure spin-current generation in YIG by NC-STOs, (2) mutual locking of a number of NC-STOs through SWs in YIG, and (3) improvement of NC-STO spectra through SW feedback in YIG. Index terms-Nanocontact spin-torque oscillators, spin waves, yttrium iron garnet
Turkish Journal of Botany
ABSTRACT
Journal of Applied Physics, 2015