KINETIC FUNCTIONS IN MAGNETOHYDRODYNAMICS WITH RESISTIVITY AND HALL EFFECT

We consider a nonlinear hyperbolic system of two conservation laws which arises in ideal magnetohydrodynamics and includes second-order terms accounting for magnetic resistivity and Hall effect. We show that the initial value problem for this model may lead to solutions exhibiting complex wave structures, including undercompressive nonclassical shock waves. We investigate numerically the subtle competition that takes place between the hyperbolic, diffusive, and dispersive parts of the system. Following Abeyratne, Knowles, LeFloch, and Truskinovsky, who studied similar questions arising in fluid and solid flows, we determine the associated kinetic function which characterizes the dynamics of undereompressive shocks driven by resistivity and Hall effect. To this end, we design a new class of ＂schemes with eontroled dissipation＂, following recent work by LeFloch and Mohammadian. It is now recognized that the equivalent equation associated with a scheme provides a guideline to design schemes that capture physically relevant, nonclassical shocks. We propose a new class of schemes based on high-order entropy conservative, finite differences for the hyperbolic flux, and high-order central differences for the resistivity and Hall terms. These schemes are tested for several regimes of （co-planar or not） initial data and parameter values, and allow us to analyze the properties of nonclassical shocks and establish the existence of monotone kinetic functions in magnetohydrodynamics.

Machine Learning Kinetic Energy Functional for a One-Dimensional Periodic System

Kinetic energy(KE) functional is crucial to speed up density functional theory calculation. However, deriving it accurately through traditional physics reasoning is challenging. We develop a generally applicable KE functional estimator for a one-dimensional (1D) extended system using a machine learning method. Our end-to-end solution combines the dimensionality reduction method with the Gaussian process regression, and simple scaling method to adapt to various 1D lattices. In addition to reaching chemical accuracy in KE calculation, our estimator also performs well on KE functional derivative prediction. Integrating this machine learning KE functional into the current orbital free density functional theory scheme is able to provide us with expected ground state electron density.

Magnetization dynamics of mixed Co–Au chains on Cu(110) substrate:Combined ab initio and kinetic Monte Carlo study

We present an investigation of the one-dimensional ferromagnetism in Au–Co nanowires deposited on the Cu（110）surface. By using the density functional theory, the influence of the nonmagnetic copper substrate Cu（110） on the magnetic properties of the bimetallic Au–Co nanowires is studied. The results show the emergence of magnetic anisotropy in the supported Au–Co nanowires. The magnetic anisotropy energy has the same order of magnitude as the exchange interaction energy between Co atoms in the wire. Our electronic structure calculation reveals the emergence of new hybridized bands between Au and Co atoms and surface Cu atoms. The Curie temperature of the Au–Co wires is calculated by means of kinetic Monte Carlo simulation. The strong size effect of the Curie temperature is demonstrated.

Effect of Jisuikang(脊髓康) on Kinetic Dysfunction in Patients after Spinal Injury

Objective： To explore the effect of Jisuikang （脊髓康, JSK） on kinetic dysfunction in patients after spinal injury. Methods： Eighty-four patients with spinal injury were assigned equally, according to a randomizing digital table to the treated group and the control group. Conventional treatment was given to both groups, and JSK was additionally given to the treated group. Changes of various kinetic function concerning parameters including kinetic score, grades of spinal injury, effectiveness of the treatment and available recovery rate in patients allocated in the treated group and the control group were observed and compared in the way issued by Association of Spinal Injury of America （ASIA）. Results： Better effects were shown in the treated group than those in the control group in improving kinetic score （92.00 ± 9.95 scores vs 83.76 ± 24.12 scores）, ASIA overall improvement rate （69.05% vs 45.24%） and grades of effectiveness （P〈0.05）. However, the difference of available recovery rate between the two groups was insignificant （P〉0.05）. Cenclusien： JSK could prevent secondary alteration of spinal injury, promote the recovery and regeneration of nerve tissues, but could not restore the function of a necrotic spine.