High-temperature spin dynamics in the one-dimensional Heisenberg system(CH3)4NMnCl3(TMMC): Spin diffusion, intra- and interchain cutoff effects

1976 ◽  
Vol 13 (9) ◽  
pp. 4098-4118 ◽  
Author(s):  
J. P. Boucher ◽  
M. Ahmed Bakheit ◽  
M. Nechtschein ◽  
M. Villa ◽  
G. Bonera ◽  
...  
Keyword(s):  
High Temperature ◽  
Spin Diffusion ◽  
Spin Dynamics ◽  
One Dimensional ◽  
The One

scholarly journals Process Model for the Production of Syngas via High Temperature Co-Electrolysis

2007 ◽  
Author(s):  
M. G. McKellar ◽  
J. E. O’Brien ◽  
C. M. Stoots ◽  
G. L. Hawkes
Keyword(s):  
Carbon Dioxide ◽  
High Temperature ◽  
Process Model ◽  
Nuclear Reactor ◽  
Flow Sheet ◽  
Process Flow ◽  
One Dimensional ◽  
Electrolysis Process ◽  
Process Flow Sheet ◽  
The One

A process model has been developed to evaluate the potential performance of a large-scale high-temperature co-electrolysis plant for the production of syngas from steam and carbon dioxide. The co-electrolysis process allows for direct electrochemical reduction of the steam-carbon dioxide gas mixture, yielding hydrogen and carbon monoxide, or syngas. The process model has been developed using the Honeywell UniSim systems analysis code. Using this code, a detailed process flow sheet has been defined that includes all the components that would be present in an actual plant such as pumps, compressors, heat exchangers, turbines, and the electrolyzer. Since the electrolyzer is not a standard UniSim component, a custom one-dimensional co-electrolysis model was developed for incorporation into the overall UniSim process flow sheet. The one dimensional co-electrolysis model assumes local chemical equilibrium among the four process-gas species via the gas shift reaction. The electrolyzer model allows for the determination of co-electrolysis outlet temperature, composition (anode and cathode sides); mean Nernst potential, operating voltage and electrolyzer power based on specified inlet gas flow rates, heat loss or gain, current density, and cell area-specific resistance. The one-dimensional electrolyzer model was validated by comparison with results obtained from a fully three dimensional computational fluid dynamics model developed using FLUENT, and by comparison to experimental data. This paper provides representative results obtained from the UniSim flow sheet model for a 300 MW co-electrolysis plant, coupled to a high-temperature gas-cooled nuclear reactor. The co-electrolysis process, coupled to a nuclear reactor, provides a means of recycling carbon dioxide back into a useful liquid fuel. If the carbon dioxide source is based on biomass, the entire process would be climate neutral.

Spin Dynamics in the One-Dimensional Antiferromagnet(CD3)4NMnCl3

1972 ◽  
Vol 5 (5) ◽  
pp. 1999-2014 ◽  
Author(s):  
M. T. Hutchings ◽  
G. Shirane ◽  
R. J. Birgeneau ◽  
S. L. Holt
Keyword(s):  
Spin Dynamics ◽  
One Dimensional ◽  
The One

A neutron scattering study of spin dynamics in the one-dimensional paramagnet CsMnBr3

1984 ◽  
Vol 62 (11) ◽  
pp. 1132-1138 ◽  
Author(s):  
B. D. Gaulin ◽  
M. F. Collins
Keyword(s):  
Neutron Scattering ◽  
Spin Wave ◽  
Spin Dynamics ◽  
Quantitative Agreement ◽  
Generalized Langevin Equation ◽  
Heisenberg Antiferromagnet ◽  
One Dimensional ◽  
Truncation Scheme ◽  
Zone Centre ◽  
The One

CsMnBr3 is a quasi-one-dimensional Heisenberg antiferromagnet. We present results of the magnetic inelastic response of CsMnBr3 across the magnetic Brillouin zone by neutron scattering techniques. Well-defined spin-wave modes, characteristic of one-dimensional magnetic insulators, are found over most of the zone in the paramagnetic phase at 15 K. The zone centre response is not sharp, but peaks in the scattering function S(k, ω) are found. No excitation branch going to zero energy at zero wavevector is found. At small wavevectors there is a mode with energy 1.7 ± 0.2 meV and we use it to identify planar anisotropy in this system. The mid-zone response as a function of temperature is analyzed in terms of a generalized Langevin equation approach (Mori formulation) to the dynamics of the one-dimensional Heisenberg antiferromagnet. The theory contains no adjustable parameters. Our results are compared with two truncation schemes of the theory. We report qualitative agreement with the theories, including the observation of upwards renormalization of spin-wave energy with temperature. Quantitative agreement is less than good for either truncation scheme.

scholarly journals Charge and spin dynamics in the one-dimensional t-Jzand t-J models

1997 ◽  
Vol 55 (10) ◽  
pp. 6491-6503 ◽  
Author(s):  
Shu Zhang ◽  
Michael Karbach ◽  
Gerhard Müller ◽  
Joachim Stolze
Keyword(s):  
Spin Dynamics ◽  
One Dimensional ◽  
The One

Nuclear relaxation at high temperature in the one-dimensional paramagnet TMMC

1974 ◽  
Vol 15 (1) ◽  
pp. 25-28 ◽  
Author(s):  
M. Ahmed-Bakheit ◽  
Y. Barjhoux ◽  
F. Ferrieu ◽  
M. Nechtschein ◽  
J-P. Boucher
Keyword(s):  
High Temperature ◽  
Nuclear Relaxation ◽  
One Dimensional ◽  
The One

scholarly journals Quantum spin dynamics of the one-dimensional planar antiferromagnet

1981 ◽  
Vol 14 (23) ◽  
pp. 3399-3422 ◽  
Author(s):  
G Muller ◽  
H Thomas ◽  
M W Puga ◽  
H Beck
Keyword(s):  
Spin Dynamics ◽  
Quantum Spin ◽  
One Dimensional ◽  
The One

scholarly journals Analytical results of the one-dimensional Hubbard model in the high-temperature limit

2001 ◽  
Vol 64 (19) ◽  
Author(s):  
I. C. Charret ◽  
E. V. Corrêa Silva ◽  
S. M. de Souza ◽  
O. Rojas Santos ◽  
M. T. Thomaz ◽  
...  
Keyword(s):  
High Temperature ◽  
Hubbard Model ◽  
Temperature Limit ◽  
One Dimensional ◽  
High Temperature Limit ◽  
Analytical Results ◽  
The One
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