Linear chain of weakly coupled defects in a three-dimensional phononic crystal: A model acoustic waveguide

2006 ◽  
Vol 74 (17) ◽  
Author(s):  
R. Sainidou ◽  
N. Stefanou ◽  
A. Modinos
Keyword(s):  
Linear Chain ◽  
Phononic Crystal ◽  
Three Dimensional ◽  
Acoustic Waveguide ◽  
Weakly Coupled

scholarly journals Prandtl Number in Classical Hard-Sphere and One-Component Plasma Fluids

Molecules ◽  
2021 ◽  
Vol 26 (4) ◽  
pp. 821
Author(s):  
Sergey Khrapak ◽  
Alexey Khrapak
Keyword(s):  
Prandtl Number ◽  
Hard Sphere ◽  
Solid Phase ◽  
Freezing Point ◽  
Three Dimensional ◽  
Order Unity ◽  
Strongly Coupled ◽  
Dielectric Fluids ◽  
Weakly Coupled ◽  
Component Plasma

The Prandtl number is evaluated for the three-dimensional hard-sphere and one-component plasma fluids, from the dilute weakly coupled regime up to a dense strongly coupled regime near the fluid-solid phase transition. In both cases, numerical values of order unity are obtained. The Prandtl number increases on approaching the freezing point, where it reaches a quasi-universal value for simple dielectric fluids of about ≃1.7. Relations to two-dimensional fluids are briefly discussed.

Thermal Design of Highly-Efficient Thermoelectric Materials With Atomic-Scale Three-Dimensional Phononic Crystals

2007 ◽  
Author(s):  
Jean-Numa Gillet ◽  
Yann Chalopin ◽  
Sebastian Volz
Keyword(s):  
Thermal Conductivity ◽  
Bulk Material ◽  
Phononic Crystal ◽  
Three Dimensional ◽  
Mean Free Path ◽  
Dispersion Curves ◽  
Phononic Crystals ◽  
Thermal Design ◽  
Atomic Scale ◽  
Thermal Insulating

Owing to their thermal insulating properties, superlattices have been extensively studied. A breakthrough in the performance of thermoelectric devices was achieved by using superlattice materials. The problem of those nanostructured materials is that they mainly affect heat transfer in only one direction. In this paper, the concept of canceling heat conduction in the three spatial directions by using atomic-scale three-dimensional (3D) phononic crystals is explored. A period of our atomic-scale 3D phononic crystal is made up of a large number of diamond-like cells of silicon atoms, which form a square supercell. At the center of each supercell, we substitute a smaller number of Si diamond-like cells by other diamond-like cells, which are composed of germanium atoms. This elementary heterostructure is periodically repeated to form a Si/Ge 3D nanostructure. To obtain different atomic configurations of the phononic crystal, the number of Ge diamond-like cells at the center of each supercell can be varied by substitution of Si diamond-like cells. The dispersion curves of those atomic configurations can be computed by lattice dynamics. With a general equation, the thermal conductivity of our atomic-scale 3D phononic crystal can be derived from the dispersion curves. The thermal conductivity can be reduced by at least one order of magnitude in an atomic-scale 3D phononic crystal compared to a bulk material. This reduction is due to the decrease of the phonon group velocities without taking into account that of the phonon average mean free path.

scholarly journals Three-dimensional phononic crystal with ultra-wide bandgap at megahertz frequencies

2021 ◽  
Vol 118 (6) ◽  
pp. 063507
Author(s):  
Julio Andrés Iglesias Martínez ◽  
Johnny Moughames ◽  
Gwenn Ulliac ◽  
Muamer Kadic ◽  
Vincent Laude
Keyword(s):  
Phononic Crystal ◽  
Three Dimensional ◽  
Wide Bandgap

Three-Dimensional Silicon Phononic Crystal

2013 ◽  
Vol 50 (6) ◽  
pp. 51-54
Author(s):  
Y.-K. Lin ◽  
H.-W. Ting ◽  
L.-J. Chou ◽  
L.-J. Chen
Keyword(s):  
Phononic Crystal ◽  
Three Dimensional

A 16-connected three-dimensional hydrogen-bonding network in tetrakis(4-aminopyridinium) perylene-3,4,9,10-tetracarboxylate octahydrate

2014 ◽  
Vol 70 (7) ◽  
pp. 668-671 ◽  
Author(s):  
Zhi-Hui Zhang ◽  
Jin-Long Wang ◽  
Ning Gao ◽  
Ming-Yang He
Keyword(s):  
Hydrogen Bonding ◽  
Hydrogen Bonds ◽  
Linear Chain ◽  
Three Dimensional ◽  
Organic Salt ◽  
Water Molecules ◽  
The Novel ◽  
One Dimensional ◽  
Connected Node ◽  
Hydrogen Bonding Network

The novel title organic salt, 4C5H7N2+·C24H8O84−·8H2O, was obtained from the reaction of perylene-3,4,9,10-tetracarboxylic acid (H4ptca) with 4-aminopyridine (4-ap). The asymmetric unit contains half a perylene-3,4,9,10-tetracarboxylate (ptca4−) anion with twofold symmetry, two 4-aminopyridinium (4-Hap+) cations and four water molecules. Strong N—H...O hydrogen bonds connect each ptca4−anion with four 4-Hap+cations to form a one-dimensional linear chain along the [010] direction, decorated by additional 4-Hap+cations attached by weak N—H...O hydrogen bonds to the ptca4−anions. Intermolecular O—H...O interactions of water molecules with ptca4−and 4-Hap+ions complete the three-dimensional hydrogen-bonding network. From the viewpoint of topology, each ptca4−anion acts as a 16-connected node by hydrogen bonding to six 4-Hap+cations and ten water molecules to yield a highly connected hydrogen-bonding framework. π–π interactions between 4-Hap+cations, and between 4-Hap+cations and ptca4−anions, further stabilize the three-dimensional hydrogen-bonding network.

Two cadmium(II) fluorous coordination compounds tuned by different bipyridines

2017 ◽  
Vol 73 (5) ◽  
pp. 424-429 ◽  
Author(s):  
Ya-Jie Kong ◽  
Peng Li ◽  
Li-Juan Han ◽  
Lu-Tong Fan ◽  
Peng-Peng Li ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Coordination Compounds ◽  
Linear Chain ◽  
Three Dimensional ◽  
Chain Structure ◽  
Water Molecules ◽  
Hydrogen Bond Acceptor ◽  
Small Surface ◽  
One Dimensional ◽  
Coordinated Water

Fluorine is the most electronegative element and can be used as an excellent hydrogen-bond acceptor. Fluorous coordination compounds exhibit several advantageous properties, such as enhanced high thermal and oxidative stability, low polarity, weak intermolecular interactions and a small surface tension compared to hydrocarbons. C—H...F—C interactions, although weak, play a significant role in regulating the arrangement of the organic molecules in the crystalline state and stabilizing the secondary structure. Two cadmium(II) fluorous coordination compounds formed from 2,2′-bipyridine, 4,4′-bipyridine and pentafluorobenzoate ligands, namely catena-poly[[aqua(2,2′-bipyridine-κ2 N,N′)(2,3,4,5,6-pentafluorobenzoato-κO)cadmium(II)]-μ-2,3,4,5,6-pentafluorobenzoato-κ2 O:O′], [Cd(C7F5O2)2(C10H8N2)(H2O)] n , (1), and catena-poly[[diaquabis(2,3,4,5,6-pentafluorobenzoato-κO)cadmium(II)]-μ-4,4′-bipyridine-κ2 N:N′], [Cd(C7F5O2)2(C10H8N2)(H2O)2] n , (2), have been synthesized solvothermally and structurally characterized. Compound (1) shows a one-dimensional chain structure composed of Cd—O coordination bonds and is stabilized by π–π stacking and O—H...O hydrogen-bond interactions. Compound (2) displays a one-dimensional linear chain structure formed by Cd—N coordination interactions involving the 4,4′-bipyridine ligand. Adjacent one-dimensional chains are extended into two-dimensional sheets by O—H...O hydrogen bonds between the coordinated water molecules and adjacent carboxylate groups. Moreover, the chains are further linked by C—H...F—C interactions to afford a three-dimensional network. In both structures, hydrogen bonding involving the coordinated water molecules is a primary driving force in the formation of the supramolecular structures.

The Yablonovite Structure as a Three-Dimensional Phononic Crystal

2019 ◽  
Vol 11 (3) ◽  
pp. 198-203 ◽  
Author(s):  
A. Konstantopoulou ◽  
N. Aravantinos-Zafiris ◽  
M.M. Sigalas
Keyword(s):  
Phononic Crystal ◽  
Three Dimensional

Magnetic Properties of the Random Mixture of the Classical Heisenberg Spins

1975 ◽  
Vol 53 (9) ◽  
pp. 854-860 ◽  
Author(s):  
Shigetoshi Katsura
Keyword(s):  
Critical Temperature ◽  
Nearest Neighbor ◽  
Linear Chain ◽  
Three Dimensional ◽  
Bethe Lattice ◽  
Zero Field ◽  
Qualitative Properties ◽  
Neighbor Interaction ◽  
Random Mixture ◽  
Ising Spins

The specific heat, the susceptibility, and the correlation function at zero field above the critical temperature of the random mixture (quenched site and bond problems) of the classical Heisenberg spins with nearest neighbor interaction were obtained exactly for the linear chain and for an infinite Bethe lattice (Bethe approximation of the two and three dimensional lattices) above the critical temperature. The results are simply expressed by the replacements of 2 cosh K → 4π (sinh K)/K and tanh K → L(K) (L(K) = Langevin function) for K = KAA, KAB, KBA, and KBB in the corresponding expressions of the random mixture of the Ising spins, and qualitative properties of both models are similar.

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