Northwest Normal University also translated into English as Northwestern Normal University is a currently a comprehensive university in Lanzhou, Gansu Province of the People's Republic of China, which is authorized by the State Council of the Central Government of the People's Republic of China to grant Associate Degrees, Bachelors' Degrees, Masters' Degrees, and Doctoral Degrees in more than 80 subject areas. Wikipedia.
Zhang X.,Northwest Normal University
Journal of Alloys and Compounds | Year: 2013
Fe-doped ZnO (ZnO:Fe) thin films were successfully prepared by radio frequency magnetron sputtering under different substrate temperatures. The properties of ZnO:Fe films were systematically studied via X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), ultraviolet visible spectrophotometer and fluorescence spectrophotometer with the emphasis on orientation, element composition, surface morphology and optical properties. The results indicated that the properties ZnO:Fe films were significantly affected by substrate temperature. XRD demonstrated that highly c-axis preferential orientation of ZnO:Fe film with wurtzite phase was fabricated exceed 300 C. The optical absorption properties and the shift of the optical band gaps were also investigated. The analysis reveals that the increasing of the band gaps was caused due to the improvement of the quality of film and the decreasing of the band gaps was likely due to the raising the concentration of carriers caused by increasing substrate temperature. Urbach energy decreased with increasing the substrate temperature from RT to 150 C while increased from 150 °C to 450 °C. The photoluminescence measurements of ZnO:Fe films at room temperature revealed a violet, a blue and a green emission and the origin of these emissions was discussed in detail. Crown Copyright © 2013 Published by Elsevier B.V. All rights reserved.
Feng H.,Northwest Normal University
Acta biochimica et biophysica Sinica | Year: 2013
Plants in their natural environment frequently face various abiotic stresses, such as drought, high salinity, and chilling. Plant mitochondria contain an alternative oxidase (AOX), which is encoded by a small family of nuclear genes. AOX genes have been shown to be highly responsive to abiotic stresses. Using transgenic plants with varying levels of AOX expression, it has been confirmed that AOX genes are important for abiotic stress tolerance. Although the roles of AOX under abiotic stresses have been extensively studied and there are several excellent reviews on this topic, the differential expression patterns of the AOX gene family members and the signal regulation of AOX gene(s) under abiotic stresses have not been extensively summarized. Here, we review and discuss the current progress of these two important issues.
Li Y.,Northwest Normal University
Computers and Mathematics with Applications | Year: 2010
In this paper the existence results of positive ω-periodic solutions are obtained for the fully third-order ordinary differential equation u‴ (t) = f (t, u (t), u′ (t), u″ (t)), t ∈ R where f ∈ C (R × (0, ∞) × R × R, R) is ω-periodic in t, and f (t, u, v, w) may be singular at u = 0. The discussion is based on a fixed point theorem in cones. © 2010 Elsevier Ltd. All rights reserved.
Gao C.,Northwest Normal University
Acta Mathematica Scientia | Year: 2014
In this paper, we consider the existence of three nontrivial solutions for a discrete non-linear multiparameter periodic problem involving the p-Laplacian. By using the similar method for the Dirichlet boundary value problems in [G. Bonanno and P. Candito, Appl. Anal., 88(4) (2009), pp. 605-616], we construct two new strong maximum principles and obtain that the boundary value problem has three positive solutions for λ and μ in some suitable intervals. The approaches we use are the critical point theory. © 2014 Wuhan Institute of Physics and Mathematics.
Dai G.,Northwest Normal University |
Ma R.,Northwest Normal University
Nonlinear Analysis: Real World Applications | Year: 2011
This paper is concerned with the existence and multiplicity of solutions to a class of p(x)-Kirchhoff type problem with Neumann boundary data of the following form -M(∫Ω1p(x)(|∇u| p(x)+|u|p(x))dx)(div(|∇u|p(x)-2∇u)- |u|p(x)-2u)=f(x,u)in Ω,∂u∂υ=0on ∂Ω. By means of a direct variational approach and the theory of the variable exponent Sobolev spaces, under appropriate assumptions on f and M, we obtain a number of results on the existence and multiplicity of solutions for the problem. In particular, we also obtain some results which can be considered as extensions of the classical result named "combined effects of concave and convex nonlinearities". Moreover, the positive solutions and the regularity of weak solutions of the problem are considered. © 2011 Elsevier Ltd. All rights reserved.