Temperature dependence of nuclear resonance frequencies in the two-dimensional ferromagnet K2CuF4

1973 ◽  
Vol 43 (1) ◽  
pp. 39-41 ◽  
Author(s):  
Le Dang Khoi ◽  
P. Veillet ◽  
J-P. Renard ◽  
C. Jacoboni
Keyword(s):  
Temperature Dependence ◽  
Nuclear Resonance ◽  
Two Dimensional ◽  
Resonance Frequencies

Pathway Complexity in the Stacking of Imine-linked Macrocycles Related to Two-Dimensional Covalent Organic Frameworks

2019 ◽  
Author(s):  
Shiwei Wang ◽  
Anton Chavez ◽  
Simil Thomas ◽  
Hong Li ◽  
Nathan C. Flanders ◽  
...  
Keyword(s):  
Temperature Dependence ◽  
Structural Similarity ◽  
Discrete Models ◽  
Side Chains ◽  
Two Dimensional ◽  
Assembly Process ◽  
Covalent Organic Frameworks ◽  
Electron Systems ◽  
Monomer Structure ◽  
Kinetic Traps

This work reports on the assembly of imine-linked macrocycles that serve as models of two-dimensional covalent organic frameworks (2D COFs). Interlayer interactions play an important role in the formation of 2D COFs, yet the effect of monomer structure on COF formation, crystallinity, and susceptibility to exfoliation are not well understood. For example, monomers with both electron-rich and electron-poor π-electron systems have been proposed to strengthen interlayer inter-actions and improve crystallinity. Here we probe these effects by studying the stacking behavior of imine-linked macrocycles that represent discrete models of 2D COFs. <div><br></div><div>Specifically, macrocycles based on terephthaldehyde (PDA) or 2,5-dimethoxyterephthaldehyde (DMPDA) stack upon cooling molecularly dissolved solutions. Both macrocycles assemble cooperatively with similar ΔHe values of -97 kJ/mol and -101 kJ/mol, respectively, although the DMPDA macrocycle assembly process showed a more straightforward temperature dependence. Circular dichroism spectroscopy performed on macrocycles bearing chiral side chains revealed a helix reversion process for the PDA macrocycles that was not observed for the DMPDA macrocycles. <br></div><div><br></div><div>Given the structural similarity of these monomers, these findings demonstrate that the stacking processes associated with nanotubes derived from these macrocycles, as well as for the corresponding COFs, are complex and susceptible to kinetic traps, casting doubt on the relevance of thermodynamic arguments for improving materials quality. <br></div>

Plasmonic excitations in two-dimensional materials: effects of structural symmetry and material anisotropy

2022 ◽  
Author(s):  
Linhui Ding ◽  
Ningning Wang ◽  
Leiming Chen ◽  
Kui Han ◽  
Xiaopeng Shen ◽  
...  
Keyword(s):  
Noble Metals ◽  
Higher Order ◽  
Two Dimensional ◽  
Material Anisotropy ◽  
Structural Symmetry ◽  
Dipole Resonance ◽  
Higher Order Modes ◽  
Resonance Frequencies ◽  
Two Dimensional Materials ◽  
Two Factors

Abstract Plasmonics in two-dimensional materials, an emerging direction of nano-optics, has attracted great attention recently, which exhibits unique properties than that in noble metals. Extending its advanced features by different manipulations is very beneficial for its promotion. In this paper, we study plasmonic excitations in graphene and black phosphorus (BP) nanostructures, where the effects of structural symmetry and material anisotropy are discussed. We show that the two factors are crucial to mode excitations, e.g. the extinction can be dominated by higher order modes rather than dipole resonance. The behavior occurs only in the direction hosting larger resonance frequencies, e.g. armchair (AC) direction of BP and shorter side of graphene rectangles. In BP rectangles along AC direction, the two factors are competing, and thus can be applied cooperatively to tune plasmonic resonance, from dipole to higher order excitations. Besides, the manipulation can also be achieved by designing BP square rings, in which the interaction between outer and inner edges show great impact on mode excitations. Our studies further promote the understanding of plasmonics in two-dimensional materials, and will pave the way for particular plasmonic applications.

Temperature dependence of the resistance of a two-dimensional topological insulator in a HgTe quantum well

2014 ◽  
Vol 89 (12) ◽  
Author(s):  
G. M. Gusev ◽  
Z. D. Kvon ◽  
E. B. Olshanetsky ◽  
A. D. Levin ◽  
Y. Krupko ◽  
...  
Keyword(s):  
Quantum Well ◽  
Temperature Dependence ◽  
Topological Insulator ◽  
Two Dimensional

Ordering kinetics of two-dimensional O(2) models: Scaling and temperature dependence

1995 ◽  
Vol 52 (2) ◽  
pp. 1550-1557 ◽  
Author(s):  
Jong-Rim Lee ◽  
Sung Jong Lee ◽  
Bongsoo Kim
Keyword(s):  
Temperature Dependence ◽  
Two Dimensional ◽  
Ordering Kinetics ◽  
Kinetics Of

Experimental Study on the Influence of Hull Spacing on Hard-Chine Catamaran Motions

2001 ◽  
Vol 45 (03) ◽  
pp. 216-227
Author(s):  
R. Centeno ◽  
K. S. Varyani ◽  
C. Guedes Soares
Keyword(s):  
Experimental Study ◽  
Cross Flow ◽  
Experimental Program ◽  
Two Dimensional ◽  
Regular Waves ◽  
Viscous Forces ◽  
Motion Responses ◽  
Resonance Frequencies ◽  
Flow Drag ◽  
Wave Induced

An experimental program was performed with hard-chine catamaran models in regular waves. The distance between the demi-hulls of the models was changed to assess its effects on the wave-induced motions. The results allowed the study of some aspects related to catamaran motions, like the interference between the hulls and resonance frequencies. The experimental results are compared with calculations performed with a recently developed code based on a two-dimensional potential flow theory in which viscous forces are included through a cross-flow drag approach. The effect of the hull distance in the heave and pitch motion responses and the importance of the viscous forces in such hull configurations are shown.

scholarly journals RESONANCES OF COASTAL WATERS BETWEEN PERTH AND GERALDTON (WESTERN AUSTRALIA)

1980 ◽  
Vol 1 (17) ◽  
pp. 16 ◽  
Author(s):  
H. Allison ◽  
A. Grassia ◽  
R. Litchfield
Keyword(s):  
Spectral Analysis ◽  
Coastal Waters ◽  
Statistical Estimation ◽  
Model Comparison ◽  
Two Dimensional ◽  
Resonance Frequencies ◽  
Sea Level Oscillations ◽  
Near Shore ◽  
Quality Factor Q ◽  
Western Australian

Sea-level oscillations along the Western Australian coast, with periods in the range of 20-40 mins, have considerably greater amplitudes between Perth and Geraldton than at other locations along the coastline. It is shown that amplification of these oscillations is due to resonance in the near shore basin formed by the shore and a submerged reef-chain parallel to and 5 km from the shore. The rigorous analytical solution for the resonance frequencies is obtained for the two-dimensional hydrodynamic model. Comparison with results from spectral analysis of recorded oscillations indicates a satisfactorily agreement with the theory. Statistical estimation of damping of the observed oscillations indicates that the predominant resonance in the first mode is sharp, having the quality factor Q=10.

Electron spin resonance of paramagnetic impurities in antiferromagnetic compounds

1991 ◽  
Vol 433 (1888) ◽  
pp. 461-468 ◽  
Keyword(s):  
Internal Field ◽  
Host Lattice ◽  
Nuclear Resonance ◽  
Dipolar Field ◽  
Exchange Field ◽  
Paramagnetic Impurities ◽  
Resonance Frequencies ◽  
Spin Resonance ◽  
Impurity Ions ◽  
Impurity Ion

The possibility of magnetic resonance measurements on an impurity in an antiferromagnetic host lattice is discussed. The ion is subject to an internal field B int ; consisting of B dip , the dipolar field generated by the antiferromagnetic moments of the host ions, that can be calculated, and an exchange field B E . For a simple two sublattice antiferromagnet, two resonance frequencies should be observed; equations for their angular dependence are given, including the effect of hyperfine interaction. Impurity ions with Kramers doublets are discussed, together with ions with singlet ground states, for which enhanced nuclear resonance should be possible. A number of simple antiferromagnetic compounds of lanthanide (4f) ions that order at liquid helium temperatures are mentioned briefly, but for simplicity, the discussion is concentrated on GdVO 4 as the host lattice. A formula, based on the known exchange field in the host lattice, is deduced for its effect on the impurity ion.

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