Groundwater evapotranspiration under psammophilous vegetation covers in the Mu Us Sandy Land, northern China

Groundwater is a significant component of the hydrological cycle in arid and semi-arid areas. Its evapotranspiration is an important part of the water budget because many plants are groundwater-dependent. To restore the degraded ecosystems, the need is pressing to further our understanding of the groundwater evapotranspiration（ET_g） in arid and semi-arid areas. This study employed the White method to estimate ET_g at four sites in the Mu Us Sandy Land in northern China, and the four sites are covered by Salix psammophila（SP site）, Artemisia ordosica（AO site）, Poplar alba（PA site）, and Carex enervis（CE site）, respectively. The depth of groundwater table and the duration of drainage were taken into account in calculating the specific yield（S_y） to improve the accuracy of the ET_g estimats. Our results showed that from late May to early November 2013 the ET_g were 361.87（SP site）, 372.53（AO site）, 597.86（PA site） and 700.76 mm（CE site）, respectively. The estimated ET_g rate was also species-dependent and the descending order of the ET_g rate for the four vegetation was： C. enervis, P. alba, A. ordosica, and S. psammophila. In addition, the depth of groundwater table has an obvious effect on the ET_g rate and the effect varied with the vegetation types. Furthermore, the evapotranspiration for the vegetation solely relying on the water supply from unsaturated layers above the groundwater table was much less than that for the vegetation heavily relying on the water supply from shallow aquifers.

Synthesis, characterization and magnetic properties of KFeO_(2) nanoparticles prepared by a simple egg white solution route

Nanoparticles of potassium ferrite(KFeO_(2))in this work were synthesized by a simple egg white solution method upon calcination in air at 773,873,and 973 K for 2 h.The effects of calcination temperature on the structural and magnetic properties of the synthesized KFeO_(2) nanoparticles were investigated.By varying the calcination temperature,X-ray diffraction and transmission electron microscopy results indicated the changes in crystallinity and morphology including particle size,respectively.Notably,the reduction in particle size of the synthesized KFeO_(2) was found to have a remarkable influence on the magnetic properties.At room temperature,the synthesized KFeO_(2) nanoparticles prepared at 873 K exhibited the highest saturation magnetization(M_(S))of 2.07×10^(4) A·m^(−1).In addition,the coercivity(H_(C))increased from 3.51 to 16.89 kA·m^(−1) as the calcination temperature increased to 973 K.The zero-field cooled(ZFC)results showed that the blocking temperatures(T_(B))of about 125 and 85 K were observed in the samples calcined at 773 and 873 K,respectively.Therefore,this work showed that the egg white solution method is simple,cost effective,and environmentally friendly for the preparation of KFeO_(2) nanoparticles.

Dynamics of a prey-predator system under Poisson white noise excitation

The classical Lotka-Volterra （LV） model is a well-known mathematical model for prey-predator ecosystems. In the present paper, the pulse-type version of stochastic LV model, in which the effect of a random natural environment has been modeled as Poisson white noise, is in- vestigated by using the stochastic averaging method. The averaged generalized It6 stochastic differential equation and Fokkerlanck-Kolmogorov （FPK） equation are derived for prey-predator ecosystem driven by Poisson white noise. Approximate stationary solution for the averaged generalized FPK equation is obtained by using the perturbation method. The effect of prey self-competition parameter e2s on ecosystem behavior is evaluated. The analytical result is confirmed by corresponding Monte Carlo （MC） simulation.

New Exact Solutions for the Wick-Type Stochastic Kudryashov–Sinelshchikov Equation

In this article, exact solutions of Wick-type stochastic Kudryashov–Sinelshchikov equation have been obtained by using improved Sub-equation method. We have used Hermite transform for transforming the Wick-type stochastic Kudryashov–Sinelshchikov equation to deterministic partial differential equation. Also we have applied inverse Hermite transform for obtaining a set of stochastic solutions in the white noise space.