Having studied the initial state energy loss versus nuclear shadowing for the Drell-Yan dimuon pairproduction in the color string model,the inhomogeneous shadowing effect is considered in this *** find thatthe inhomog...
详细信息
Having studied the initial state energy loss versus nuclear shadowing for the Drell-Yan dimuon pairproduction in the color string model,the inhomogeneous shadowing effect is considered in this *** find thatthe inhomogeneous shadowing effect does amend the rate of energy loss per unit path length,-dE/***,thetheoretical results for the Drell-Yan differential cross-section ratios are compared with the E772 and E866 *** isfound that the theoretical results are in good agreement with the experimental data.
The stochastic generalized Ginzburg-Landau equation with additive noise can be solved pathwise and the unique solution generates a random system. Then we prove the random system possesses a global random attractor in ...
详细信息
The stochastic generalized Ginzburg-Landau equation with additive noise can be solved pathwise and the unique solution generates a random system. Then we prove the random system possesses a global random attractor in H 0 1 .
In this paper,we study the initial-boundary value problem of one class of nonlinear Schr(o)dinger equations described in molecular ***,the existence of the global solution is obtained by means of interpolation inequal...
详细信息
In this paper,we study the initial-boundary value problem of one class of nonlinear Schr(o)dinger equations described in molecular ***,the existence of the global solution is obtained by means of interpolation inequality and a priori estimation.
The semiclassical limit in the transient quantum drift-diffusion equations with isentropic pressure in one space dimension is rigorously proved. The equations are supplemented with homogeneous Neumann boundary conditi...
详细信息
The semiclassical limit in the transient quantum drift-diffusion equations with isentropic pressure in one space dimension is rigorously proved. The equations are supplemented with homogeneous Neumann boundary conditions. It is shown that the semiclassical limit of this solution solves the classical drift-diffusion model. In the meanwhile, the global existence of weak solutions is proved.
Lattice Boltzmann （LB） modeling of high-speed compressible flows has long been attempted by various authors. One common weakness of most of previous models is the instability problem when the Mach number of the flow...
详细信息
Lattice Boltzmann （LB） modeling of high-speed compressible flows has long been attempted by various authors. One common weakness of most of previous models is the instability problem when the Mach number of the flow is large. In this paper we present a finite-difference LB model, which works for flows with flexible ratios of specific heats and a wide range of Mach number, from 0 to 30 or higher. Besides the discrete-velocity-model by Watari [Physica A 382 （2007） 502], a modified Lax Wendroff finite difference scheme and an artificial viscosity are introduced. The combination of the finite-difference scheme and the adding of artificial viscosity must find a balance of numerical stability versus accuracy. The proposed model is validated by recovering results of some well-known benchmark tests： shock tubes and shock reflections. The new model may be used to track shock waves and/or to study the non-equilibrium procedure in the transition between the regular and Mach reflections of shock waves, etc.
A shell-model version of passive scalar problem is introduced, which is inspired by the model of K. Ohkitani and M. Yakhot [K. Ohkitani and M. Yakhot, Phys. Rev. Lett. 60 （1988） 983; K. Ohkitani and M. Yakhot, Prog....
详细信息
A shell-model version of passive scalar problem is introduced, which is inspired by the model of K. Ohkitani and M. Yakhot [K. Ohkitani and M. Yakhot, Phys. Rev. Lett. 60 （1988） 983; K. Ohkitani and M. Yakhot, Prog. Theor. Phys. 81 （1988） 329]. As in the original problem, the prescribed random velocity field is Gaussian and 5 correlated in time. Deterministic differential equations are regarded as nonlinear Langevin equation. Then, the Fokker-Planck equations of PDF for passive scalars are obtained and solved numerically. In energy input range （n 〈 5, n is the shell number.）, the probability distribution function （PDF） of passive scalars is near the Gaussian distribution. In inertial range （5≤ n ≤ 16） and dissipation range （n ≥ 17）, the probability distribution function （PDF） of passive scalars has obvious intermittence. And the scaling power of passive scalar is anomalous. The results of numerical simulations are compared with experimental measurements.
Spin-polarised density functional theory (DFT-B3LYP) energies, harmonic vibrational frequencies, and moments of inertia are used to construct modified Arrhenius rate expressions for elementary steps in chain-propagati...
详细信息
Spin-polarised density functional theory (DFT-B3LYP) energies, harmonic vibrational frequencies, and moments of inertia are used to construct modified Arrhenius rate expressions for elementary steps in chain-propagation and chain-branching pathways for dimethyl ether combustion. Barrierless reactions were treated with variational RRKM theory, and global kinetics were modeled using master equation and perfectly stirred reactor simulations. Our kinetics analysis suggests that the bottleneck along the chain propagation path is the isomerisation of CH3OCH2OO, contrary to earlier interpretations. Comparing the rate constants for competing decomposition pathways of the key chain-branching intermediate hydroperoxymethyl formate (HPMF), we find that formation of formic acid and the atmospherically relevant Criegee intermediate (CH2OO) via a H-bonded adduct may be more favourable than O-O bond scission. Since the latter forms a source of a second OH radical beyond that supplied in chain propagation, which is necessary for explosive combustion, the more favourable pathway to formic acid may inhibit autoignition of the fuel. We predict that the HPMF O-O scission product, OCH2OC(=O)H, most likely directly dissociates to HCO + HC(=O)OH. This implies an overabundance of CO at 550-700 K, since HC(=O)OH is a fairly stable product in this temperature range and facile H abstraction from HCO leads to CO. We find that CO2 product yields are sensitive to the creation of CH2OO and that creation of CH2OO is competitive with the O-O scission reaction.
The authors consider the well-posedness in energy space of the critical non-linear system of wave equations with Hamiltonian structure{utt-△u=-F1（｜u｜^2,｜v｜^2）u,utt-△u=-F2（｜u｜^2,｜v｜^2）u where there exists...
详细信息
The authors consider the well-posedness in energy space of the critical non-linear system of wave equations with Hamiltonian structure{utt-△u=-F1（｜u｜^2,｜v｜^2）u,utt-△u=-F2（｜u｜^2,｜v｜^2）u where there exists a function F（λ,μ） such that δF（λ,μ）/δλ=F1（λ,μ）.δF（λ,μ）/δμ=F2（λ,μ） By showing that the energy and dilation identities hold for weak solution under some assumptions on the non-linearities, we prove the global well-posedness in energy space by a similar argument to that for global regularity as shown in ＂Shatah and Struwe＇s paper, Ann. of Math. 138, 503-518 （1993）＂.
Functional Magnetic Resonance Imaging (fMRI) provides dynamical access into the complex functioning of the human brain, detailing the hemodynamic activity of thousands of voxels during hundreds of sequential time poin...
详细信息
ISBN:
(纸本)160560352X
Functional Magnetic Resonance Imaging (fMRI) provides dynamical access into the complex functioning of the human brain, detailing the hemodynamic activity of thousands of voxels during hundreds of sequential time points. One approach towards illuminating the connection between fMRI and cognitive function is through decoding;how do the time series of voxel activities combine to provide information about internal and external experience? Here we seek models of fMRI decoding which are balanced between the simplicity of their interpretation and the effectiveness of their prediction. We use signals from a subject immersed in virtual reality to compare global and local methods of prediction applying both linear and nonlinear techniques of dimensionality reduction. We find that the prediction of complex stimuli is remarkably low-dimensional, saturating with less than 100 features. In particular, we build effective models based on the decorrelated components of cognitive activity in the classically-defined Brodmann areas. For some of the stimuli, the top predictive areas were surprisingly transparent, including Wernicke's area for verbal instructions, visual cortex for facial and body features, and visual-temporal regions for velocity. Direct sensory experience resulted in the most robust predictions, with the highest correlation (c ∼ 0:8) between the predicted and experienced time series of verbal instructions. Techniques based on non-linear dimensionality reduction (Laplacian eigenmaps) performed similarly. The interpretability and relative simplicity of our approach provides a conceptual basis upon which to build more sophisticated techniques for fMRI decoding and offers a window into cognitive function during dynamic, natural experience.
Using R-matrix method, the collision cross sections of sodium from ground state to the first a few excited states at incident energy range 0-5.4 eV are calculated. The influence of the Rydberg states to the collision ...
Using R-matrix method, the collision cross sections of sodium from ground state to the first a few excited states at incident energy range 0-5.4 eV are calculated. The influence of the Rydberg states to the collision cross sections is elucidated, which implies the cross sections obtained by partial wave expansion methods at low-energy could be interfaced with the cross sections obtained by first Born approximation methods at high-energy.
暂无评论