Commensurability between vortex spacing and half the crystal lattice constant inNdBa2Cu3Oysingle crystals

2002 ◽  
Vol 66 (6) ◽  
Author(s):  
H. Küpfer ◽  
G. Ravikumar ◽  
Th. Wolf ◽  
A. A. Zhukov ◽  
A. Will ◽  
...  
Keyword(s):  
Crystal Lattice ◽  
Lattice Constant ◽  
Crystal Lattice Constant

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.

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 Calculation of Dynamic Hardness by Molecular Dynamics

2019 ◽  
Vol 221 ◽  
pp. 01005
Author(s):  
Alexey Bolesta
Keyword(s):  
Molecular Dynamics ◽  
Crystal Lattice ◽  
Molecular Dynamic Simulation ◽  
Dynamic Simulation ◽  
Nanocrystalline Materials ◽  
Polycrystalline Copper ◽  
Dynamic Hardness ◽  
Solid Ball ◽  
The Impact ◽  
Crystal Lattice Constant

Based on the molecular-dynamic simulation of the impact of a solid ball on the surface of polycrystalline copper, a method for calculating the dynamic hardness of nanocrystalline materials is proposed. It is proposed to carry out the calculation of hardness by dividing the impact work by the squeezed volume. It is shown that this expression of dynamic hardness is consistent with Meyer hardness in the case of quasistatic indentation. As a result of this simulation, it is shown that under conditions when the diameter of the impactor decreases and approaches the crystal lattice constant of the target, the dynamic hardness increases. Also, in the calculations, the impactor density varied approximately twice, which was equal to the density of steel and the density of tungsten carbide. For a striker diameter of 5 nm, dynamic hardness increases with the speed of the striker and does not depend on its density.

Atomic structure of stair rod misfit dislocations at the GaAs on Si(100) interface

1990 ◽  
Vol 48 (4) ◽  
pp. 342-343
Author(s):  
D. Gerthsen
Keyword(s):  
Lattice Constant ◽  
Atomic Structure ◽  
Spherical Aberration ◽  
Stacking Faults ◽  
Misfit Dislocations ◽  
Gaas On Si ◽  
Thermal Expansion Coefficients ◽  
Transmission Electron ◽  
Intersection Line ◽  
Oriented Parallel

The prospect of technical applications has induced a lot of interest in the atomic structure of the GaAs on Si(100) interface and the defects in its vicinity which are often studied by high resolution transmission electron microscopy. The interface structure is determined by the 4.1% lattice constant mismatch between GaAs and Si, the large difference between the thermal expansion coefficients and the polar/nonpolar nature of the GaAs on Si interface. The lattice constant mismatch is compensated by misfit dislocations which are characterized by a/2<110> Burgers vectors b which are oriented parallel or inclined on {111} planes with respect to the interface. Stacking faults are also frequently observed. They are terminated by partial dislocations with b = a/6<112> on {111} planes. In this report, the atomic structure of stair rod misfit dislocations is analysed which are located at the intersection line of two stacking faults at the interface.A very thin, discontinous film of GaAs has been grown by MBE on a Si(100) substrate. Fig.1.a. shows an interface section of a 27 nm wide GaAs island along [110] containing a stair rod dislocation. The image has been taken with a JEOL 2000EX with a spherical aberration constant Cs = 1 mm, a spread of focus Δz = 10 nm and an angle of beam convergence ϑ of 2 mrad.

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