Giant magnetoimpedance in crystalline Mumetal

We studied giant magnetoimpedance (GMI) effect in commercial crystalline Mumetal, with the emphasis to sample thickness dependence and annealing effects. By using appropriate heat treatment one can achieve GMI ratios as high as 310%, and field sensitivity of about 20%/Oe, which is comparable to the best GMI characteristics obtained for amorphous and nanocrystalline soft magnetic materials.Comment: 8 pages, 3 figure

Differential quadrature method for space-fractional diffusion equations on 2D irregular domains

In mathematical physics, the space-fractional diffusion equations are of particular interest in the studies of physical phenomena modelled by L\'{e}vy processes, which are sometimes called super-diffusion equations. In this article, we develop the differential quadrature (DQ) methods for solving the 2D space-fractional diffusion equations on irregular domains. The methods in presence reduce the original equation into a set of ordinary differential equations (ODEs) by introducing valid DQ formulations to fractional directional derivatives based on the functional values at scattered nodal points on problem domain. The required weighted coefficients are calculated by using radial basis functions (RBFs) as trial functions, and the resultant ODEs are discretized by the Crank-Nicolson scheme. The main advantages of our methods lie in their flexibility and applicability to arbitrary domains. A series of illustrated examples are finally provided to support these points.Comment: 25 pages, 25 figures, 7 table

Comprehensive Evaluation of Endophytic Fungi and Rhizosphere Soil Fungi on the Growth of \u3cem\u3eAchnatherum inebrians\u3c/em\u3e

This study was conducted to clarify the effect of endophytic fungi and rhizosphere soil fungi on the growth of Achnatherum inebrians. In this study, the seeds of A. inebrians with endophyte-infected (EI) and endophyte-free (EF) were used as materials. Eight fungi isolated from rhizosphere soil were inoculated through germination and greenhouse pot experiment. The results showed that the endophytes, rhizosphere soil fungi and their combined effect all had significant effect on the seed germination and plant growth of A. inebrians, and the affected factors varied with the tested materials and strains. Through comprehensive evaluation of principal component analysis and subordinate function, it was found that the overall growth performance of EI was better than that of EF plants, and the strains that inhibited the growth of A. inebrians were Cladosporium. sp2 and Fusarium sp1

Analysis and Research on Influencing Factors of Coal Reservoir Permeability

The permeability of coal is an important parameter in the theory of coal reservoir gas flow. Experiments have demonstrated that after the coal matrix adsorbs gas, adsorption swelling deformation will occur and when gas desorbs from coal matrix, it undergoes a shrinkage deformation. A new formula for estimating permeability is developed. By considering the adsorption swelling and desorption shrinkage deformation in this formula for permeability, the effect of coal matrix swelling and shrinkage on coal reservoir permeability is studied. The study shows that, as gas in the coal reservoir desorbs, gas pressure decreases and the coal matrix shrinks, so as to make swelling deformation smaller and increase the permeability of the coal reservoir. In addition, the influence of effective stress, Klinkenberg effects, burial depth and natural fracture on coal reservoir permeability is analyzed. The analysis and research is of significance to coal mine gas disaster prevention and coal bed methane gas resource development

Oscillatory instability in a driven granular gas

We discovered an oscillatory instability in a system of inelastically colliding hard spheres, driven by two opposite "thermal" walls at zero gravity. The instability, predicted by a linear stability analysis of the equations of granular hydrodynamics, occurs when the inelasticity of particle collisions exceeds a critical value. Molecular dynamic simulations support the theory and show a stripe-shaped cluster moving back and forth in the middle of the box away from the driving walls. The oscillations are irregular but have a single dominating frequency that is close to the frequency at the instability onset, predicted from hydrodynamics.Comment: 7 pages, 4 figures, to appear in Europhysics Letter