scholarly journals High-performance Tunable Multichannel Absorbers Couple with Graphene-based Grating and Dual-Tamm Plasmonic Structures

2021 ◽  
Author(s):  
Jinlei Hu ◽  
Zhengda Hu ◽  
Jicheng Wang ◽  
Aliaksei Balmakou ◽  
Sergei Khakhomov ◽  
...  
Keyword(s):  
High Performance ◽  
Chemical Potential ◽  
Grating Period ◽  
Polarization Angle ◽  
Perfect Absorption ◽  
Plasmonic Structures ◽  
Resonant Modes ◽  
Tamm State ◽  
High Level ◽  
Absorption Filter

Abstract We present a hybrid Tamm system targeting the tunable multichannel absorber. The proposed optical absorber is analyzed and investigated by using the transfer matrix method (TMM). The numerical and theoretical studies show that the four perfect absorption peaks are generated by two types of resonant modes excited in the structure, which can be reasonably explained by the guide-mode resonance (GMR) and optical Tamm state (OTS). More importantly, the strong interaction between the two modes gives rise to mode hybridization by adjusting the grating period. Furthermore, the active modulation of the GMR-based peak can be manipulated discretely by tuning the polarization angle or continuously by changing the chemical potential of graphene. The presented optical absorption filter will meet high level of effectiveness in developing high-performance optoelectronic devices.

scholarly journals High-Performance Tunable Multichannel Absorbers Couple with Graphene-Based Grating and Dual-Tamm Plasmonic Multilayer Structures

2021 ◽  
Author(s):  
Jinlei Hu ◽  
Zheng-Da Hu ◽  
Jicheng Wang ◽  
Aliaksei Balmakou ◽  
Sergei Khakhomov ◽  
...  
Keyword(s):  
Strong Coupling ◽  
High Performance ◽  
Near Infrared ◽  
Chemical Potential ◽  
Matrix Theory ◽  
Grating Period ◽  
Polarization Angle ◽  
Optical Resonance ◽  
Perfect Absorption ◽  
Infrared Frequencies

Abstract We present a tunable multichannel absorbers in a hybird optical Tamm system at near-infrared frequencies. The simulation results reveal the structure capable of exciting four perfect absorption peaks, which are generated by two types of resonance, namely a guide-mode resonance (GMR) in a graphene-based grating and optical resonance induced by Tamm states in metal-photonic crystal heterostructure-metal (M-PCH-M) composites based on transfer matrix theory (TMT). The numerical and theoretical studies show that the strong coupling between the two modes gives rise to mode hybridization by adjusting the grating period. Coupled mode theory (CMT) has been employed to explain the strong coupling phenomenon. Furthermore, the active modulation of the GMR-based peak can be manipulated discretely by tuning the polarization angle or continuously by changing the chemical potential of graphene. The presented optical absorption filter is going to satisfy high level of effectiveness when developing perspective high-performance optoelectronic devices including modulators, switches, solar cells, thermal radiation and wave filters.

A single-patterned five-band terahertz metamaterial absorber based on multiple resonance mechanisms

2018 ◽  
Vol 32 (03) ◽  
pp. 1850029 ◽  
Author(s):  
Zong-De Ju ◽  
Guo-Qing Xu ◽  
Zhi-Hua Wei ◽  
Jing Li ◽  
Qian Zhao ◽  
...  
Keyword(s):  
High Performance ◽  
Imaging System ◽  
Metamaterial Absorber ◽  
Polarization Angle ◽  
Absorption Mechanism ◽  
Perfect Absorption ◽  
Simple Method ◽  
Multiple Resonance ◽  
Resonance Modes ◽  
Single Pattern

A single-patterned five-band terahertz metamaterial absorber based on simple metal–dielectric–metal sandwich structure is investigated and demonstrated. The numerical simulations reveal the different dependence of the absorption ability on the incident polarization angle, dielectric layer, and structural dimensions of the single pattern. The extracted electric field distribution indicates that the five-band near-perfect absorption performance (average over 98%) mainly originates from the combination of LC, dipole, quadrupole, and high-order resonance. The researches on magnetic field and power loss density distributions further reveal the absorption mechanism. Moreover, additional resonance mode can be excited to form a six-band high-performance absorber only by adjusting some geometric dimensions of the single pattern with multiple resonance modes. The simple method provides us a very good idea to implement a super multi-band absorber. The proposed absorbers here can be applied in massive related fields, such as metamaterial sensors, thermal radiation, and imaging system.

scholarly journals Tunable Terahertz Absorption with Optical Tamm State in the Graphene-Bragg Reflector Configuration

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Shuai Wang ◽  
Guimei Li ◽  
Yanhong Zou
Keyword(s):  
Fermi Energy ◽  
High Performance ◽  
Optoelectronic Devices ◽  
Dielectric Constants ◽  
Bragg Reflector ◽  
Absorption Peak ◽  
Perfect Absorption ◽  
Terahertz Absorption ◽  
Tamm State ◽  
Specific Incident

Tunable terahertz absorption in the interface between graphene and dielectric Bragg reflector (DBR) has been numerically demonstrated. The near perfect absorption mainly originates from the enhancement of the electric field owing to the excitation of the optical Tamm state (OTS) at the interface between graphene and dielectric Bragg mirror. It has been found that the absorption peak occurs at specific incident angles, which can be employed for realizing the frequency and angular absorbers. Further, we demonstrate that the position of the absorption peak can be tuned by changing the Fermi energy of graphene. Moreover, the behaviors of the near perfect absorption are strongly related to the dielectric constants and thicknesses of the surrounding dielectrics. The tunability of graphene-DBR structure absorption may help to find favorable applications for the realization of high-performance graphene optoelectronic devices.

What Can Digitization Do For Formulated Product Innovation and Development

2020 ◽  
Author(s):  
James McDonagh ◽  
William Swope ◽  
Richard L. Anderson ◽  
Michael Johnston ◽  
David J. Bray
Keyword(s):  
High Performance ◽  
Quality Data ◽  
High Quality Data ◽  
Base Level ◽  
Hybrid Approaches ◽  
Digital Ecosystem ◽  
Recent Developments ◽  
Chemical Simulation ◽  
High Level ◽  
Physical And Chemical

Digitization offers significant opportunities for the formulated product industry to transform the way it works and develop new methods of business. R&D is one area of operation that is challenging to take advantage of these technologies due to its high level of domain specialisation and creativity but the benefits could be significant. Recent developments of base level technologies such as artificial intelligence (AI)/machine learning (ML), robotics and high performance computing (HPC), to name a few, present disruptive and transformative technologies which could offer new insights, discovery methods and enhanced chemical control when combined in a digital ecosystem of connectivity, distributive services and decentralisation. At the fundamental level, research in these technologies has shown that new physical and chemical insights can be gained, which in turn can augment experimental R&D approaches through physics-based chemical simulation, data driven models and hybrid approaches. In all of these cases, high quality data is required to build and validate models in addition to the skills and expertise to exploit such methods. In this article we give an overview of some of the digital technology demonstrators we have developed for formulated product R&D. We discuss the challenges in building and deploying these demonstrators.<br>

https://imsciences.edu.pk/files/journals/vol12_2/New%201%20MA.864.pdf

2020 ◽  
Vol 12 (2) ◽  
pp. 19-50 ◽  
Author(s):  
Muhammad Siddique ◽  
Shandana Shoaib ◽  
Zahoor Jan
Keyword(s):  
Organizational Performance ◽  
Structural Equation ◽  
High Performance ◽  
Service Sector ◽  
Performance Outcomes ◽  
Theory And Practice ◽  
Relational Coordination ◽  
Multiple Sources ◽  
And Performance ◽  
High Level

A key aspect of work processes in service sector firms is the interconnection between tasks and performance. Relational coordination can play an important role in addressing the issues of coordinating organizational activities due to high level of interdependence complexity in service sector firms. Research has primarily supported the aspect that well devised high performance work systems (HPWS) can intensify organizational performance. There is a growing debate, however, with regard to understanding the “mechanism” linking HPWS and performance outcomes. Using relational coordination theory, this study examines a model that examine the effects of subsets of HPWS, such as motivation, skills and opportunity enhancing HR practices on relational coordination among employees working in reciprocal interdependent job settings. Data were gathered from multiple sources including managers and employees at individual, functional and unit levels to know their understanding in relation to HPWS and relational coordination (RC) in 218 bank branches in Pakistan. Data analysis via structural equation modelling, results suggest that HPWS predicted RC among officers at the unit level. The findings of the study have contributions to both, theory and practice.

scholarly journals Graphene Nanoribbon Gap Waveguides for Dispersionless and Low-Loss Propagation with Deep-Subwavelength Confinement

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1302
Author(s):  
Zhiyong Wu ◽  
Lei Zhang ◽  
Tingyin Ning ◽  
Hong Su ◽  
Irene Ling Li ◽  
...  
Keyword(s):  
High Performance ◽  
Chemical Potential ◽  
Shape Change ◽  
Optical Switch ◽  
Pulse Amplitude ◽  
Propagation Distance ◽  
Graphene Nanoribbon ◽  
Low Loss ◽  
High Loss ◽  
On Chip

Surface plasmon polaritons (SPPs) have been attracting considerable attention owing to their unique capabilities of manipulating light. However, the intractable dispersion and high loss are two major obstacles for attaining high-performance plasmonic devices. Here, a graphene nanoribbon gap waveguide (GNRGW) is proposed for guiding dispersionless gap SPPs (GSPPs) with deep-subwavelength confinement and low loss. An analytical model is developed to analyze the GSPPs, in which a reflection phase shift is employed to successfully deal with the influence caused by the boundaries of the graphene nanoribbon (GNR). It is demonstrated that a pulse with a 4 μm bandwidth and a 10 nm mode width can propagate in the linear passive system without waveform distortion, which is very robust against the shape change of the GNR. The decrease in the pulse amplitude is only 10% for a propagation distance of 1 μm. Furthermore, an array consisting of several GNRGWs is employed as a multichannel optical switch. When the separation is larger than 40 nm, each channel can be controlled independently by tuning the chemical potential of the corresponding GNR. The proposed GNRGW may raise great interest in studying dispersionless and low-loss nanophotonic devices, with potential applications in the distortionless transmission of nanoscale signals, electro-optic nanocircuits, and high-density on-chip communications.

scholarly journals Dietary and Ergogenic Supplementation to Improve Elite Soccer Players’ Performance

2021 ◽  
pp. 1-7
Author(s):  
Haniel Fernandes
Keyword(s):  
Dietary Supplements ◽  
High Performance ◽  
Scientific Literature ◽  
Soccer Players ◽  
Competitive Sport ◽  
Beetroot Juice ◽  
Improve Performance ◽  
Sustained Release Tablets ◽  
High Level ◽  
Ergogenic Supplements

<b><i>Background:</i></b> Soccer is an extremely competitive sport, where the most match important moments can be defined in detail. Use of ergogenic supplements can be crucial to improve the performance of a high-performance athlete. Therefore, knowing which ergogenic supplements are important for soccer players can be an interesting strategy to maintain high level in this sport until final and decisive moments of the match. In addition, other supplements, such as dietary supplements, have been studied and increasingly referenced in the scientific literature. But, what if ergogenic supplements were combined with dietary supplements? This review brings some recommendations to improve performance of soccer athletes on the field through dietary and/or ergogenic supplements that can be used simultaneously. <b><i>Summary:</i></b> Soccer is a competitive sport, where the match important moments can be defined in detail. Thus, use of ergogenic supplements covered in this review can improve performance of elite soccer players maintaining high level in the match until final moments, such as creatine 3–5 g day<sup>−1</sup>, caffeine 3–6 mg kg<sup>−1</sup> BW around 60 min before the match, sodium bicarbonate 0.1–0.4 g kg<sup>−1</sup> BW starting from 30 to 180 min before the match, β-alanine 3.2 and 6.4 g day<sup>−1</sup> provided in the sustained-release tablets divided into 4 times a day, and nitrate-rich beetroot juice 60 g in 200 mL of water (6 mmol of NO3<sup>−</sup> L) around 120 min before match or training, including a combination possible with taurine 50 mg kg<sup>−1</sup> BW day<sup>−1</sup>, citrulline 1.2–3.4 g day<sup>−1</sup>, and arginine 1.2–6 g day<sup>−1</sup>. <b><i>Key Messages:</i></b> Soccer athletes can combine ergogenic and dietary supplements to improve their performance on the field. The ergogenic and dietary supplements used in a scientifically recommended dose did not demonstrate relevant side effects. The use of various evidence-based supplements can add up to further improvement in the performance of the elite soccer players.

scholarly journals Long Term Interactions of Native and Invasive Species in a Marine Protected Area Suggest Complex Cascading Effects Challenging Conservation Outcomes

Diversity ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 71
Author(s):  
Charalampos Dimitriadis ◽  
Ivoni Fournari-Konstantinidou ◽  
Laurent Sourbès ◽  
Drosos Koutsoubas ◽  
Stelios Katsanevakis
Keyword(s):  
Invasive Species ◽  
Native Species ◽  
High Performance ◽  
Marine Protected Area ◽  
Habitat Degradation ◽  
Population Increase ◽  
Rocky Reef ◽  
Cascading Effects ◽  
High Level

Understanding the interactions among invasive species, native species and marine protected areas (MPAs), and the long-term regime shifts in MPAs is receiving increased attention, since biological invasions can alter the structure and functioning of the protected ecosystems and challenge conservation efforts. Here we found evidence of marked modifications in the rocky reef associated biota in a Mediterranean MPA from 2009 to 2019 through visual census surveys, due to the presence of invasive species altering the structure of the ecosystem and triggering complex cascading effects on the long term. Low levels of the populations of native high-level predators were accompanied by the population increase and high performance of both native and invasive fish herbivores. Subsequently the overgrazing and habitat degradation resulted in cascading effects towards the diminishing of the native and invasive invertebrate grazers and omnivorous benthic species. Our study represents a good showcase of how invasive species can coexist or exclude native biota and at the same time regulate or out-compete other established invaders and native species.

scholarly journals Evaluation of Static Mapping for Dynamic Space-Shared Multi-task Processing on FPGAs

2021 ◽  
Author(s):  
Umar Ibrahim Minhas ◽  
Roger Woods ◽  
Georgios Karakonstantis
Keyword(s):  
High Performance ◽  
Design Space Exploration ◽  
Design Space ◽  
System Throughput ◽  
Design Parameters ◽  
Temporal Constraints ◽  
Shared Resources ◽  
Task Processing ◽  
High Level ◽  
Performance Computing

AbstractWhilst FPGAs have been used in cloud ecosystems, it is still extremely challenging to achieve high compute density when mapping heterogeneous multi-tasks on shared resources at runtime. This work addresses this by treating the FPGA resource as a service and employing multi-task processing at the high level, design space exploration and static off-line partitioning in order to allow more efficient mapping of heterogeneous tasks onto the FPGA. In addition, a new, comprehensive runtime functional simulator is used to evaluate the effect of various spatial and temporal constraints on both the existing and new approaches when varying system design parameters. A comprehensive suite of real high performance computing tasks was implemented on a Nallatech 385 FPGA card and show that our approach can provide on average 2.9 × and 2.3 × higher system throughput for compute and mixed intensity tasks, while 0.2 × lower for memory intensive tasks due to external memory access latency and bandwidth limitations. The work has been extended by introducing a novel scheduling scheme to enhance temporal utilization of resources when using the proposed approach. Additional results for large queues of mixed intensity tasks (compute and memory) show that the proposed partitioning and scheduling approach can provide higher than 3 × system speedup over previous schemes.

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