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931.
By means of in-situ diffuse reflectance FTIR.The IR spectra of 6 coals with different ranks were obtained from room temperature to 230℃.A new curve fitting method was used to recognize the different hydrogen bonds in the coals.and the influence of coal ranks on the distribution of hydrogen bonds(HBs) in the coals and their thermal stability were discussed.The results show that there is another new HB(around 2514cm^-1) between the-SH in mercaptans or thiophenols and the nitrogen in the pyridine-like compounds in the coals.and the evidence for that was provided.The controversial band of the HB between hydroxyl and the nitrogen of the pyridine-like compounds was determined in the range of 3028-2984cm^-1,and the result is comsistent with but more specific than that of Painter et al.It was ound that the stability of different HBs in the coals is influenced by both coal rank and temperature,For some HBs.the higher the coal rank,the higher the stability of them.Within the temperature range of our research,the stability of the HB between the hydroxyl and the π bond increases to some extent for some coals at temperatures higher than 110 or 140℃. 相似文献
932.
We study the quantum fluctuations of the charge and current of two L-C dissipative mesoscopic circuit with the mutual inductance in the vacuum state.Our results show that the system state will evolve to a squeezed coherent state under the effect of external source.We find that the squeezing amplitude parameter is relative to the parameters of circuit and the mutual-inductance coefficient in the existence of dissipation.When the circuit has no dissipation or there is complete coupling between two meshes,the squeezing amplitude parameter only depends on the capacitance‘s ratio. 相似文献
933.
We study the finite-size scaling behavior of velocity and central charge for different coupling constants and different phases in (1 1)-dimensional lattice model in very short chains.Using XXZ spin 1/2 chains with 15 or fewer sites,we demonstrate the weak finite-size dependence of spinon velocity for any magnitude of coupling strength Jz and the strong phase dependence of central charge.This behavior of velocity and central charge in different coupling constants and different phases gives a method to determine phase transitions of (1 1)-dimensional models.This method is simple and efficient by utilizing only the ground state energy of very short finite-size chains.It is also general and powerfur for various one-dimensional lattice models and it uncovers eventhe weakest berezinski-Kosterlitz-Thouless phase transitions. 相似文献
934.
We proposed a simple spin-1/2 model which provides an exactly solvable example to study the Ising criticality with central charge c=1/2.By mapping it onto the real Majorana fermions,the Ising critical behavior in explored explicitly,although its bosonized form is not the double frequency sine-Gordon model. 相似文献
935.
By making use of the diagrammatic techniques in perturbation theory,we have investigated the Hall effect in a quasi-two dimensional disordered electron system.In the weakly localized regime,the analytical expression for quantum correction to Hall conductivity has been obtained using the kubo formalism and quasiclassical approximation.The relevant dimensional crossover behavior from three dimensions to two dimensions with decreasing the interlayer hopping energy is discussed.The quantum interference effect is shown to have a vanishing correction to the Hall coefficient. 相似文献
936.
Stability of Crystal Growth Face and Dissolution Face in Crystallization from Solution under Microgravity 总被引:1,自引:0,他引:1
The stability of the shapes of crystal growth face and dissolution face in a two-dimensional mathematical model of crystal growth from solution under microgravity is studied.It is proved that the stable shapes of crystal growth face and dissolution face do exist,which are suitably shaped curves with their upper parts inclined backward properly.The stable shapes of crystal growth faces and dissolution faces are calculated for various values of parameters,Ra,Pr and Sc.It is shown that the stronger the convection relative to the diffusion in solution is,the more backward the upper parts of the stable crystal growth face and dissolution face are inclined.The orientation and the shape of dissolution face hardly affect the stable shape of crystal growth face and vice versa. 相似文献
937.
In this second paper of a series of papers,we explore the difference discrete versions for the Euler-Lagrange cohomology and apply them to the symplectic or multisymplectic geometry and their preserving properties in both the Lagrangian and Hamiltonian formalisms for discrete mechanics and field theory in the framework of multiparameter differential approach.In terms of the difference discrete Euler-Lagrange cohomological concepts,we show that the symplectic or multisymplectic geometry and their difference discrete structure-preserving properties can always be established not only in the solution spaces of the discrete Euler-Lagrange or canonical equations erived by the difference discrete variational principle but also in the function space in each case if and only if the relevant closed Euler-Lagrange cohomological conditions are satisfied. 相似文献
938.
Long-range effects on the pyroelectric coefficient of a ferroelectric superlattice consisting of two different ferroelectric materials are investigated based on the transverse Ising model.The effects of the interfacial coupling and the thickness of one period on the pyroelectric coefficient of the ferroelectric superlattics are studied by taking into account the long-range interaction.It is found that with the increase of the strength of the long-range interaction,the pyroelectric coefficient decreases when the temperature is lower than the phase transition temperature;the mumber of the pyroelectric peaks decreases gradually and the phase transition temperature increases,It is also found that with the decrease of the interfacial coupling and the thickness of one period.the phase transition temperature and the number of the pyroelectric peaks decrease. 相似文献
939.
Evolution process can be calculated from the relativistic hydrodynamic equation with certain estimated initial conditions about a single spherical fireball here.So one can estimate a kind of initial condition qualitatively with a possible energy density about ε0≈1.9 GeV/fm^3,and to fit the experimental data at thermal freeze-out based on this process.The evolution from a cylindrical fireball is discussed simply. 相似文献
940.
We demonstrate a method for controlling strong chaos by an aperiodic perturbation in two-dimensional Hamiltonian systems.The method has the advantages that the controlled system remains conservative property and the selection of the perturbation has a considerable diversity.We illustrate this method with two area preserving maps:the non-monotonic twist map which is a mixed system and the perturbed cat map which exhibits hard chaos.Numerical results show that the strong chaos can be effectively controlled into regular motions,and the final states are always quasiperiodic ones.The method is robust against the presence of weak external noise. 相似文献