scholarly journals The Rise of (Chiral) 3D Mechanical Metamaterials

Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3527 ◽  
Author(s):  
Janet Reinbold ◽  
Tobias Frenzel ◽  
Alexander Münchinger ◽  
Martin Wegener
Keyword(s):  
Crystal Lattice ◽  
Lattice Constant ◽  
Linear Polarization ◽  
Three Dimensional ◽  
Future Perspectives ◽  
Special Issue ◽  
Polarization Rotation ◽  
Mechanical Metamaterials ◽  
The One ◽  
Crystal Lattice Constant

On the occasion of this special issue, we start by briefly outlining some of the history and future perspectives of the field of 3D metamaterials in general and 3D mechanical metamaterials in particular. Next, in the spirit of a specific example, we present our original numerical as well as experimental results on the phenomenon of acoustical activity, the mechanical counterpart of optical activity. We consider a three-dimensional chiral cubic mechanical metamaterial architecture that is different from the one that we have investigated in recent early experiments. We find even larger linear-polarization rotation angles per metamaterial crystal lattice constant than previously and a slower decrease of the effects towards the bulk limit.

Characterization of crystal lattice constant and dislocation density of crack-free GaN films grown on Si(111)

2010 ◽  
Vol 257 (4) ◽  
pp. 1161-1165 ◽  
Author(s):  
Jijun Xiong ◽  
Jianjun Tang ◽  
Ting Liang ◽  
Yong Wang ◽  
Chenyang Xue ◽  
...  
Keyword(s):  
Dislocation Density ◽  
Crystal Lattice ◽  
Lattice Constant ◽  
Crystal Lattice Constant

scholarly journals Characterization of The Volcanic Rocks of Mount Sinabung, Simacem Village, Karo Regency, Conducted With XRD, SEM-EDX

2019 ◽  
Vol 1 (1) ◽  
pp. 1-5
Author(s):  
Perdinan Sinuhaji
Keyword(s):  
Crystal Lattice ◽  
Lattice Constant ◽  
Elemental Analysis ◽  
Volcanic Rocks ◽  
Lattice Constants ◽  
Crystal System ◽  
Tetragonal Crystals ◽  
Hexagonal Crystals ◽  
Crystal Lattice Constant

The study of volcanic rocks characterization of Sinabung Volcano erupted on September 15, 2017. The volcanic rocks crystal system was performed with XRD, elemental analysis and microstructure with SEM-EDX. Volcanic rocks contain: Anorthite phase 87,11 (wt%), Triclinic crystal, lattice constant, a = 8.1742 Å, b = 12,844 Å, c = 14,204 Å; Quartz phase 2.26%, Hexagonal crystals, lattice constants, a = 4,799 Å, b = 4,799 Å, c = 5,379 Å; Cristobalite phase 7.72 (wt%), Tetragonal crystals, lattice constants a = 4,970 Å, b = 6,990 Å, c = 6,998 Å; Alunite phase 2.91 (wt%), Hexagonal crystals, lattice constants, a = 6,990 Å, b = 6,990 Å, c = 17,282 Å.

scholarly journals Исследование характеристик сверхрешетки InGaAs/InAlGaAs для вертикально-излучающих лазеров спектрального диапазона 1300 nm

2021 ◽  
Vol 91 (12) ◽  
pp. 2008
Author(s):  
С.А. Блохин ◽  
А.В. Бабичев ◽  
А.Г. Гладышев ◽  
Л.Я. Карачинский ◽  
И.И. Новиков ◽  
...  
Keyword(s):  
Crystal Lattice ◽  
Quantum Wells ◽  
Lattice Constant ◽  
Current Density ◽  
Lattice Mismatch ◽  
Active Regions ◽  
Cavity Surface ◽  
Excitation Power Density ◽  
Emitting Lasers ◽  
Crystal Lattice Constant

X-ray structural analysis and photoluminescence spectroscopy techniques were used to study heterostructures based on InGaAs/InAlGaAs superlattice for active regions of 1300 nm range lasers grown by molecular beam epitaxy. It is shown that the grown heterostructures have a high crystal quality. The perpendicular lattice mismatch of the average crystal lattice constant of the InGaAs/InAlGaAs superlattice with respect to the crystal lattice constant of the InP substrate is estimated at ~ +0.01%. An analysis of the photoluminescence spectra made it possible to conclude that the contribution of Auger recombination is insignificant in the studied range of excitation power density. Studies of vertical-cavity surface-emitting lasers with an active region based on the InGaAs/InAlGaAs superlattice made it possible to estimate the gain coefficient at a level of 650 cm-1 for the standard logarithmic approximation of the dependence of the gain on the current density. The transparency current density of the laser was ~150 А/cm2, which is comparable to the record low values for the case of highly strained InGaAs-GaAs and InGaAsN-GaAs quantum wells in the spectral ranges of 1200 nm and 1300 nm, respectively.

scholarly journals A Multi Polarization Square Patch Antenna with a Reconfigurable Feeding Network

2021 ◽  
Author(s):  
Roozbeh Rezaeipour
Keyword(s):  
Circular Polarization ◽  
Linear Polarization ◽  
Signal Strength ◽  
Reconfigurable Antenna ◽  
Polarization Rotation ◽  
Power Dividers ◽  
Switching Circuits ◽  
Specific Frequency ◽  
The One

<p>Rotation of polarization is the one of problem in communication with linear polarization. In fact, it can reduce the received signal strength down to -20 dB in some cases. Circular polarization is one the accessible approaches for sorting this problem due to it can be immune against polarization rotation. In this paper, proposed antenna can perform in linear and circular polarization which can be switched according to the condition of signal which is being transmitted. Consequently, environmental disruptions could not decline the quality of communication. 1) The proposed antenna is categorized in reconfigurable antennas which have different methods for implementation. First of all, the proposed antenna is a multi-polarization reconfigurable antenna that can radiate circular polarization and linear polarization on the same structure at a specific frequency. Moreover, a simple feeding network for this antenna is implemented. This antenna utilizes common power dividers for feeding the square patch. Finally, switching circuits which are used for changing polarization in this antenna are by far simple than that of existing works.</p>

Density and Mechanical Strength of Ferrite for Inertial Gyroscope

2007 ◽  
Vol 546-549 ◽  
pp. 2265-2268
Author(s):  
Zhong Yu ◽  
Zhong Wen Lan ◽  
Ke Sun ◽  
Yu Chen
Keyword(s):  
Grain Size ◽  
Fracture Surface ◽  
Crystal Lattice ◽  
Lattice Constant ◽  
Bending Strength ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zn Ferrite ◽  
Electronic Microscope ◽  
Crystal Lattice Constant

The effects of NiO on density and mechanic strength of Mn-Zn ferrite used for inertial gyroscope were investigated by measurements of crystal lattice constant, Vickers hardness, bending strength. To investigate this further, powder of Mn-Zn ferrite was characterized by x-ray diffraction (XRD) and the fracture surface of Mn-Zn ferrite was checked by scanning electronic microscope (SEM). The investigation revealed that the substitution of Ni2+ modified crystal lattice constant and crystal grain size so that it caused crystal lattice constant of Mn-Zn ferrite to decline and crystal grain size to decrease, therefore it was useful to improve density and mechanic strength of Mn-Zn ferrite by this way. The results show that proper addition of NiO can bring higher density and more perfect mechanic strength of Mn-Zn ferrite used for inertial gyroscope.

scholarly journals Mathematical and computational modeling of biological systems: advances and perspectives

2021 ◽  
Vol 8 (4) ◽  
pp. 318-321
Author(s):  
Carlo Bianca ◽  
◽  
Keyword(s):  
Computational Models ◽  
Biological Systems ◽  
Future Perspectives ◽  
Special Issue ◽  
Mathematical Structures ◽  
Recent Developments ◽  
Quantitative Validation ◽  
The One ◽  
Definition Of ◽  
Mathematical And Computational Modeling

<abstract> <p>The recent developments in the fields of mathematics and computer sciences have allowed a more accurate description of the dynamics of some biological systems. On the one hand new mathematical frameworks have been proposed and employed in order to gain a complete description of a biological system thus requiring the definition of complicated mathematical structures; on the other hand computational models have been proposed in order to give both a numerical solution of a mathematical model and to derive computation models based on cellular automata and agents. Experimental methods are developed and employed for a quantitative validation of the modeling approaches. This editorial article introduces the topic of this special issue which is devoted to the recent advances and future perspectives of the mathematical and computational frameworks proposed in biosciences.</p> </abstract>

scholarly journals A Multi Polarization Square Patch Antenna with a Reconfigurable Feeding Network

2021 ◽  
Author(s):  
Roozbeh Rezaeipour
Keyword(s):  
Circular Polarization ◽  
Linear Polarization ◽  
Signal Strength ◽  
Reconfigurable Antenna ◽  
Polarization Rotation ◽  
Power Dividers ◽  
Switching Circuits ◽  
Specific Frequency ◽  
The One

<p>Rotation of polarization is the one of problem in communication with linear polarization. In fact, it can reduce the received signal strength down to -20 dB in some cases. Circular polarization is one the accessible approaches for sorting this problem due to it can be immune against polarization rotation. In this paper, proposed antenna can perform in linear and circular polarization which can be switched according to the condition of signal which is being transmitted. Consequently, environmental disruptions could not decline the quality of communication. 1) The proposed antenna is categorized in reconfigurable antennas which have different methods for implementation. First of all, the proposed antenna is a multi-polarization reconfigurable antenna that can radiate circular polarization and linear polarization on the same structure at a specific frequency. Moreover, a simple feeding network for this antenna is implemented. This antenna utilizes common power dividers for feeding the square patch. Finally, switching circuits which are used for changing polarization in this antenna are by far simple than that of existing works.</p>

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