scholarly journals Дважды отрицательные среды на основе антиферромагнитных метаматериалов для терагерцевого диапазона частот

2021 ◽  
Vol 47 (18) ◽  
pp. 32
Author(s):  
С.В. Гришин ◽  
М.Д. Амельченко ◽  
Ю.П. Шараевский ◽  
С.А. Никитов
Keyword(s):  
Periodic Structure ◽  
Theoretical Study ◽  
Terahertz Range ◽  
Two Dimensional ◽  
Dispersion Characteristics ◽  
Thin Conducting ◽  
Study Results

The paper presents the theoretical study results of the dispersion characteristics of electromagnet-ic waves existing in antiferromagnetic (AFM) metamaterial. The AFM metamaterial consists of a transversely magnetized antiferromagnet, inside of which a two-dimensional periodic structure of thin conducting wires surrounded by insulators is placed. It has been established that the AFM metamaterial has two frequency ranges, in which there are backward waves, and the material pa-rameters of the medium are twice negative. The indicated areas are located in the terahertz range.

scholarly journals Дважды отрицательные среды на основе антиферромагнитных полупроводников для терагерцевого диапазона частот

2022 ◽  
Vol 48 (5) ◽  
pp. 39
Author(s):  
С.В. Гришин ◽  
А.В. Богомолова ◽  
С.А. Никитов
Keyword(s):  
Electromagnetic Waves ◽  
Theoretical Study ◽  
The Other ◽  
Terahertz Range ◽  
Dispersion Characteristics ◽  
Gyrotropic Medium ◽  
Material Parameters

The paper presents the results of a theoretical study of the dispersion characteristics of electromagnetic waves (EMW) existing in a transversely magnetized antiferromagnetic (AFM) semiconductor with loss. An AFM semiconductor is an infinite bi-gyrotropic medium, the effective material parameters of which are twice negative in several frequency ranges. It was found that these frequency regions are in the terahertz range and there are four backward EMEs in them, two of which are TE waves, and the other two are TM waves.

Terahertz-wave generation using graphene

2012 ◽  
Vol 1437 ◽  
Author(s):  
Taiichi Otsuji ◽  
Stephane Boubanga Tombet ◽  
Akira Satou ◽  
Maxim Ryzhii ◽  
Victor Ryzhii
Keyword(s):  
Terahertz Wave ◽  
Wave Generation ◽  
Nonequilibrium Carrier ◽  
Terahertz Range ◽  
Two Dimensional ◽  
Carrier Relaxation ◽  
Dynamic Conductivity ◽  
Electrically Pumped ◽  
Terahertz Lasers ◽  
Recombination Dynamics

ABSTRACTIn this paper recent advances in terahertz-wave generation in graphene are reviewed. First, fundamental basis of the optoelectronic properties of graphene is introduced. Second, nonequilibrium carrier relaxation and recombination dynamics in optically or electrically pumped graphene is described to introduce a possibility of negative dynamic conductivity in a wide terahertz range. Third, recent theoretical advances toward the creation of current-injection graphene terahertz lasers are described. Fourth, unique terahertz dynamics of the two-dimensional plasmons in graphene are described. Finally, the advantages of graphene materials and devices for terahertz-wave generation are summarized.

Optimization of Phononic Crystals for the Simultaneous Attenuation of Out-of-Plane and In-Plane Waves

2011 ◽  
Author(s):  
Osama R. Bilal ◽  
Mahmoud I. Hussein
Keyword(s):  
Genetic Algorithm ◽  
Phononic Crystal ◽  
Plane Waves ◽  
Phononic Crystals ◽  
Gap Size ◽  
Two Dimensional ◽  
Dispersion Characteristics ◽  
Out Of Plane ◽  
Optimization Methodology ◽  
Application Specific

The topological distribution of the material phases inside the unit cell composing a phononic crystal has a significant effect on its dispersion characteristics. This topology can be engineered to produce application-specific requirements. In this paper, a specialized genetic-algorithm-based topology optimization methodology for the design of two-dimensional phononic crystals is presented. Specifically the target is the opening and maximization of band gap size for (i) out-of-plane waves, (ii) in-plane waves and (iii) both out-of-plane and in-plane waves simultaneously. The methodology as well as the resulting designs are presented.

Applied-Information Technology in Willingness of Online Group Buying for College Students

2014 ◽  
Vol 685 ◽  
pp. 540-544
Author(s):  
Xiao Ting Li ◽  
Lin Zhong ◽  
Shou Wen Ji
Keyword(s):  
College Students ◽  
College Student ◽  
Theoretical Study ◽  
Influence Factors ◽  
Reference Value ◽  
Group Buying ◽  
Study Results ◽  
Management Recommendations ◽  
Online Group ◽  
Operation And Management

As a new e-commerce model, network group purchase develops rapidly for its advantages such as conservation and convenience. The college student is an important part of consumer of the online group buying, so the research on college student willingness has a important reference value for the expansion of market. Firstly, the article has a theoretical study on the influence factors of willingness of Online Group Buying for college students and carries out related questionnaires. Secondly, the article makes factor analysis, correlation analysis, multiple regression analysis using the statistical software of SPSS19.0. Finally, this paper proposes corresponding operation and management recommendations for relevant participants in online group-buying according to the study results.

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