scholarly journals Numerical investigation and Comparative analysis of tunable graphene-gold metasurface based polarizer structures for infrared frequency

Author(s):  
Vishal Sorathiya ◽  
shobhit patel

Abstract We present the comparative analysis of tunable graphene-based metasurface polarizer structure THz frequency range. This polarizer structures have been numerically investigated over the 10 THz to 25 THz of the frequency range. Reflectance co-efficient, phase variation, and phase difference parameters have been investigated to identify the behavior of polarization effect over the range of 10 THz to 25 THz of the frequency. The proposed polarizer has been also investigated for the different shapes of the top gold resonator structure. The proposed structure is tunable for the range of 0.1 eV to 0.9 eV of the graphene Fermi energy. The proposed structure also works on the wide range of the input incident wave of the X and Y polarization. This structure having small, compact tunable design and it can be used as a basic building block in the large THz circuits and structures.

2021 ◽  
Author(s):  
Vishal Sorathiya ◽  
Shobhit K Patel

Abstract This paper proposes the tunable graphene-assisted polarizer structure which is working on the infrared frequency range. The tunable polarizer has been designed by a three-layered structure of silica, graphene, and gold. The polarizer behavior of the structure is analyzed for the frequency range of 3 to 12 THz. The tunability of the structure is analyzed for the different values of fermi energy which is tunable parameter of single-layer graphene sheet. Polarizer response is derived in terms of different performance parameters such as reflectance, phase variation, phase difference, polarization conversion rate, and effective refractive indices. Graphene-based polarizer structure is investigated for the co-polarization and cross-polarization input incident conditions to check linear to circular polarization conversion. It also shows an effective refractive index response to check the metasurface behavior of the polarizer for 3 to 12 THz range. We have observed that the polarization amplitude becomes stronger for the higher Fermi energy value of the graphene sheet. The reflection amplitude is achieved up to 90%. Results of the proposed polarizer structure can be used to design the various electro-optical structure which operates in the lower THz range.


2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sanjai Kumar Shukla ◽  
Sushil

PurposeOrganizational capabilities are crucial to achieve the objectives. A plethora of maturity models is available to guide organizational capabilities that create a perplexing situation about what stuff to improve and what to leave. Therefore, a unified maturity model addressing a wide range of capabilities is a necessity. This paper establishes that a flexibility maturity model is an unified model containing the operational, strategic and human capabilities.Design/methodology/approachThis paper does a comparative analysis/benchmarking studies of different maturity models/frameworks widely used in the information technology (IT) sector with respect to the flexibility maturity model to establish its comprehensiveness and application in the organization to handle multiple goals.FindingsThis study confirms that the flexibility maturity model has the crucial elements of all the maturity models. If the organizations use the flexibility maturity model, they can avoid the burden of complying with multiple ones and become objective-driven rather than compliance-driven.Research limitations/implicationsThe maturity models used in information technology sectors are used. This work will inspire other maturity models to adopt flexibility phenomena.Practical implicationsThe comparative analysis will give confidence in application of flexibility framework. The business environment and strategic options across organizations are inherently different that the flexibility maturity model well handles.Social implicationsA choice is put to an organization to see the comparison tables produced in this paper and choose the right framework according to the prevailing business situation.Originality/valueThis is the first study that makes a conclusion based on comparative benchmarking of existing maturity models.


2016 ◽  
Vol 34 (4) ◽  
pp. 427-436 ◽  
Author(s):  
Larisa Trichtchenko

Abstract. Power transmission lines above the ground, cables and pipelines in the ground and under the sea, and in general all man-made long grounded conductors are exposed to the variations of the natural electromagnetic field. The resulting currents in the networks (commonly named geomagnetically induced currents, GIC), are produced by the conductive and/or inductive coupling and can compromise or even disrupt system operations and, in extreme cases, cause power blackouts, railway signalling mis-operation, or interfere with pipeline corrosion protection systems. To properly model the GIC in order to mitigate their impacts it is necessary to know the frequency dependence of the response of these systems to the geomagnetic variations which naturally span a wide frequency range. For that, the general equations of the electromagnetic induction in a multi-layered infinitely long cylinder (representing cable, power line wire, rail or pipeline) embedded in uniform media have been solved utilising methods widely used in geophysics. The derived electromagnetic fields and currents include the effects of the electromagnetic properties of each layer and of the different types of the surrounding media. This exact solution then has been used to examine the electromagnetic response of particular samples of long conducting structures to the external electromagnetic wave for a wide range of frequencies. Because the exact solution has a rather complicated structure, simple approximate analytical formulas have been proposed, analysed and compared with the results from the exact model. These approximate formulas show good coincidence in the frequency range spanning from geomagnetic storms (less than mHz) to pulsations (mHz to Hz) to atmospherics (kHz) and above, and can be recommended for use in space weather applications.


2020 ◽  
Vol 27 (5) ◽  
pp. 16-22
Author(s):  
Yu. N. Ivanov ◽  
T. A. Khomenko

The article considers a wide range of questions pertaining to possible and applicable harmonization of business accounting and the SNA which would, if implemented, facilitate the improvement of the information base for the compilation of national accounts and consistency of analysis of economy at micro and macro levels. The authors note that total harmonization of the two systems of information cannot be achieved due to diff erences in their key objectives. The harmonization of selected indicators and classifi cation, however, is possible and useful. In this context, the views on this matter of internationally-recognized national accounts experts, such as R. Ruggles (the USA) and F. Bos (the Netherlands), are commented on. A comparative analysis of concepts and defi nitions of some indicators of both systems is presented in the article. In particular, the diff erences between the income defi nitions. For instance, it is noted that the SNA defi nition of income is based on the concept developed by J. Hiсks and it excludes income from sales of assets and holding gains, whereas in business accounting this method is not adopted. The diff erences between two systems in defi nitions of sale of output, input, profi t and methods of valuation of indicators are also described in the article. The authors substantiate the possible directions and sequence of individual steps to the harmonization of the SNA and business accounting in the Russian Federation. They emphasize the need for close interaction between Rosstat and the Ministry of Finance of Russia in carrying out this vital work, which is necessary for creating single information, statistical and methodological space in Russia, to improve the quality of statistics and accounting, analytical work in general and management decisions.


2020 ◽  
Author(s):  
Arcangela Bollino ◽  
Anna Maria Marotta ◽  
Federica Restelli ◽  
Alessandro Regorda ◽  
Roberto Sabadini

<p>Subduction is responsible for surface displacements and deep mass redistribution. This rearrangement generates density anomalies in a wide spectrum of wavelengths which, in turn, causes important anomalies in the Earth's gravity field that are visible as lineaments parallel to the arc-trench systems. In these areas, when the traditional analysis of the deformation and stress fields is combined with the analysis of the perturbation of the gravity field and its slow time variation, new information on the background environment controlling the tectonic loading phase can be disclosed.</p><p>Here we present the results of a comparative analysis between the geodetically retrieved gravitational anomalies, based on the EIGEN-6C4 model, and those predicted by a 2D thermo-chemical mechanical modeling of the Sumatra and Mariana complexes.</p><p>The 2D model accounts for a wide range of parameters, such as the convergence velocity, the shallow dip angle, the different degrees of coupling between the facing plates. The marker in cell technique is used to compositionally differentiate the system. Phase changes in the crust and in the mantle and mantle hydration are also allowed. To be compliant with the geodetic EIGEN-6C4 gravity data, we define a model normal Earth considering the vertical density distribution at the margins of the model domain, where the masses are not perturbed by the subduction process.</p><p>Model predictions are in good agreement with data, both in terms of wavelengths and magnitude of the gravity anomalies measured in the surroundings of the Sumatra and Marina subductions. Furthermore, our modeling supports that the differences in the style of the gravity anomaly observed in the two areas are attributable to the different environments – ocean-ocean or ocean-continental subduction – that drives a significantly different dynamic in the wedge area.</p>


2022 ◽  
Vol 23 (1) ◽  
Author(s):  
Jing Ren ◽  
Qun Yao ◽  
Minjie Tian ◽  
Feng Li ◽  
Yueqiu Chen ◽  
...  

Abstract Background Migraine is a common and disabling primary headache, which is associated with a wide range of psychiatric comorbidities. However, the mechanisms of emotion processing in migraine are not fully understood yet. The present study aimed to investigate the neural network during neutral, positive, and negative emotional stimuli in the migraine patients. Methods A total of 24 migraine patients and 24 age- and sex-matching healthy controls were enrolled in this study. Neuromagnetic brain activity was recorded using a whole-head magnetoencephalography (MEG) system upon exposure to human facial expression stimuli. MEG data were analyzed in multi-frequency ranges from 1 to 100 Hz. Results The migraine patients exhibited a significant enhancement in the effective connectivity from the prefrontal lobe to the temporal cortex during the negative emotional stimuli in the gamma frequency (30–90 Hz). Graph theory analysis revealed that the migraine patients had an increased degree and clustering coefficient of connectivity in the delta frequency range (1–4 Hz) upon exposure to positive emotional stimuli and an increased degree of connectivity in the delta frequency range (1–4 Hz) upon exposure to negative emotional stimuli. Clinical correlation analysis showed that the history, attack frequency, duration, and neuropsychological scales of the migraine patients had a negative correlation with the network parameters in certain frequency ranges. Conclusions The results suggested that the individuals with migraine showed deviant effective connectivity in viewing the human facial expressions in multi-frequencies. The prefrontal-temporal pathway might be related to the altered negative emotional modulation in migraine. These findings suggested that migraine might be characterized by more universal altered cerebral processing of negative stimuli. Since the significant result in this study was frequency-specific, more independent replicative studies are needed to confirm these results, and to elucidate the neurocircuitry underlying the association between migraine and emotional conditions.


2017 ◽  
Vol 6 (4) ◽  
pp. 133-139
Author(s):  
Olcay Boratav

AbstractThe concept of art has varied according to space and time perspective in each and every period and it has emerged in different forms in every culture. Artists or designers produce a wide range of forms with different materials representing the period and culture while creating their ceramics. Ceramics symbolizes a thousand-year-old endeavor as well as being considered as one of the arts. It has shed light on the history in different shapes and cultures in addition to undertaking the task of conveyance of art with original structure and formal style in the works of art. Ceramics makes identity differences thanks to background knowledge, form and decorative techniques and originality. Art is not for society’s sake; it aims to relieve the tension, to satisfy pleasure, to enable people to see and hear, to use and to evaluate. Different cultures have generated new styles in their ceramics by integrating creativity into their own traditions and techniques as well as interacting with Mayan vases and pots, Greek pottery, Anatolian ceramics and tiles. Some of these impacts have been so profound in ceramics that they have been passed on from generation to generation.This paper seeks to address to the following questions: How was ceramics used in different cultures and periods with composition features such as form, decoration, motif and figure; and how has it undertaken the task of conveyance of art by investigating what features they have. Keywords: ceramics, art, conveyance of art, form, figure.


Author(s):  
Anita Sh. Ishmukhametova ◽  

Identification of names of plant curatives and substances in folk and fiction texts shows close interactions between man and the world, attitudes of people towards nature. Research in phytonyms and medicinal plant names proper is most essential for the understanding of a nation’s cultural heritage. The paper examines the lexeme балтырған in Bashkir discourse. Materials. The analyzed materials include linguistic dictionaries, folklore and fiction texts of the Machine Fund of the Bashkir Language, and etymological dictionaries of Altaic languages. Goals. The study aims at a comparative investigation of the lexeme балтырған ‘hogweed’. Results. The term proves a widespread phytonym in Bashkir discourse, which is attested by that it denotes a wide range of plant species in Bashkir and has parallels in other Turkic and Mongolic languages. The lexeme is included in academic, explanatory, dialectal, phrasal, and mythological dictionaries of the Bashkir language. The comparative analysis shows that baltyrγan ‘hogweed’ usually denotes a plant of the order Apiales, a medicinal herb. Baltyrγan~ baltirγana contains the initial bal / baltïr / baldïr with the meaning ‘green, young, fresh’.


2019 ◽  
Vol 75 (4) ◽  
pp. 610-623
Author(s):  
Jun-ichi Yoshimura

Using a theory of X-ray diffraction moiré fringes developed in a previous paper, labelled Part I [Yoshimura (2015). Acta Cryst. A71, 368–381], the X-ray moiré images of a silicon bicrystal having a weak curvature strain and an interspacing gap, assumed to be integrated for an incident-wave angular width, are simulation-computed over a wide range of crystal thicknesses and incident-wave angular width, likely under practical experimental conditions. Along with the simulated moiré images, the graphs of characteristic quantities on the moiré images are presented for a full understanding of them. The treated moiré images are all of rotation moiré. Mo Kα1 radiation and the 220 reflection were assumed in the simulation. The results of this simulation show that fringe patterns, which are significantly modified from simple straight fringes of rotation moiré, appear in some ranges of crystal thicknesses and incident-wave angular width, due to a combined effect of Pendellösung oscillation and an added phase difference from the interspacing gap, under the presence of a curvature strain. The moiré fringes which slope to the perpendicular direction to the diffraction vector in spite of the assumed condition of rotation moiré, and fringe patterns where low-contrast bands are produced with a sharp bend of fringes arising along the bands are examples of the modified fringe pattern. This simulation study provides a wide theoretical survey of the type of bicrystal moiré image produced under a particular condition.


Author(s):  
Md Mohiuddin ◽  
Asma Akther ◽  
Eun Byul Jo ◽  
Hyun Chan Kim ◽  
Jaehwan Kim

The present study investigates a film actuator made with dielectric cellulose acetate films separated by narrow spacers as a means of electrostatic actuation for potential haptic application. Fabrication process for the actuator is explained along with experiments conducted over a wide frequency range of actuation frequency. A valid finite element simulation of the actuator is made on the quarter section of the actuator by using full 3D finite elements. Vibration characteristics such as fundamental natural frequency, mode shape and output velocity in the frequency range for haptic feeling generation are obtained from the finite element analysis and compared with the experimental results. Experimental results demonstrate that the finite element model is practical and effective enough in predicting the vibration characteristics of the actuator for haptic application. The film actuator shows many promising properties like high transparency, wide range of actuation frequency and high vibration velocity for instance.


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