Dingxi, China
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Li X.-F.,Tianshui Normal University | Feng X.-Q.,Tianshui Normal University | Yang S.,Dingxi Teachers College | Zhang Y.-X.,Tianshui Normal University
Faguang Xuebao/Chinese Journal of Luminescence | Year: 2012

Succinic-oligochitosan-Eu (III) complex was synthesized and characterized. Under simulated physiological conditions, the interaction between complex and bovine serum albumins (BSA) was studied by ultraviolet spectrum and fluorescence spectrum. The results showed that the absorption intensity of BSA increased with the concentration of complex. The complex quenched the fluorescence of BSA and it was static quenching, and then the binding constant and binding sites were calculated. They were 2.068 2×10 4 L·mol -1 and 1.094 72 at room temperature, respectively.

Tian Y.-L.,Dingxi Teachers College | Tian Y.-L.,Nanjing University | Yan Y.,Nanjing University | Li H.,Nanjing University | And 3 more authors.
Physical Review D - Particles, Fields, Gravitation and Cosmology | Year: 2012

In this paper, we employ the equation of state (EOS) of the quasiparticle model proposed in A.M. Zhao, Mod. Phys. Lett. A 25, 47 (2010)MPLAEQ0217-732310. 1142/S0217732310031361] which incorporates the effect of vacuum negative pressure to study the properties of quark stars. In our model the EOS has the correct behavior required by QCD in the small and large μ limit. We employ this EOS to calculate the mass-radii relation and mass-energy density relation of quark stars. Our results are found to be consistent with the most recent astronomical observations. © 2012 American Physical Society.

An Z.,Dingxi Teachers College | He X.,U.S. Center for Disease Control and Prevention | Gao W.,Gansu Agricultural University | Zhao W.,Gansu Agricultural University | Zhang W.,Gansu Agricultural University
Journal of Food Science | Year: 2014

Miniature Cheddar-type cheeses were produced using microbial rennet from Bacillus amyloliquefaciens (milk-clotting enzyme [MCE]) or calf rennet (CAR). With the exception of pH, there were no significant differences in gross composition between MCE-cheese (MCE-C) and CAR-cheese (CAR-C). The pH value of CAR-C was significantly higher than that of MCE-C at 40 and 60 d of ripening. The total nitrogen content of the pH 4.6-soluble fraction obtained from MCE-C was higher than that obtained from CAR-C. However, nitrogen content of the 12% TCA-soluble fraction was similar between CAR-C and MCE-C. The extent of αs1-casein and β-casein hydrolysis, measured by urea-PAGE, was similar in both cheese samples. The hydrolysis of β-casein was lower than that of αs1-casein. Different reverse phase-high-performance liquid chromatography peptide profiles of ethanol-soluble and ethanol-insoluble fractions were obtained from CAR-C and MCE-C. The peptide content in the 2 cheese samples increased throughout ripening; the ratio of hydrophobic to hydrophilic peptides was lower in MCE-C than in CAR-C. Compared with CAR-C, MCE-C was softer as a result of higher protein hydrolysis. Microbial rennet from B. amyloliquefaciens contributed to higher proteolytic rates, which reduced ripening time. © 2014 Institute of Food Technologists®.

Wang T.,Northwest Normal University | Wang T.,Dingxi Teachers College | Tang S.,Shandong Business Institute
Jixie Qiangdu/Journal of Mechanical Strength | Year: 2013

Wave function expansion method and Green function method were used to study the scattering effect of the body supported by an elastic column locating on the half space surface to incident out-of-plane SH (shearing horizontal) waves. First, a hyperbolic partial differential equation definite problem was solved to determine the free displacement and the corresponding Green function in the half space. Then, superposition principle was used to determine the total displacement in the half space with the the body supported by an elastic column locating on the surface, and the dynamic response equation of the body is given with the use of Newton law. Last, the definite integration equation of the unknown force can be obtained and solved with the displacement boundary conditions and the mechanical boundary conditions. The given example numerical solutions show the practicability and feasibility of the method here.

Jiao J.-Y.,Dingxi Teachers College | Gui L.-D.,CAS Institute of Soil and Water Conservation | Jia G.-J.,Dingxi Teachers College
Journal of Ecology and Rural Environment | Year: 2013

In order to explore effects of comprehensive management of small watersheds on sustainable development of ecological economy in the semi-arid loess hilly-gully regions, ecological footprints of the demands and supplies of the Miaop-ing watershed before and after the implementation of ecological environment management were calculated quantitatively and analyzed using the footprint theory and method, based on the data obtained through field survey. Results show that the ecological footprint of the watershed has always been greater than its ecological carrying capacity, thus leaving the small watershed ecological economy in unsustainable state. However, its per capita ecological deficit has dropped from 0. 798 9 hm2 before the management to 0. 552 5 hm2 after the management. Thanks to the the remarkable effect of the comprehensive management of soil and water conservation, its ecological carrying capacity grows faster than its ecological footprint. Ecological footprint demand and deficit comes mainly from alienation of land by farmlands and fossil energy industry.

Wang Y.,Dingxi Teachers College | Yang S.,Dingxi Teachers College | Fang J.,Lanzhou Jiaotong University | Li B.,Lanzhou Jiaotong University
Journal of Coatings Technology Research | Year: 2015

Polymethylsilsesquioxane (PMSQ) is highly heat and weather resistant and is excellent as a coating material. In the present work, the precursor for PMSQ, methyltrimethoxysilane (MTMS), was emulsified in aqueous medium with the aid of sodium silicate. It was found that at a proper concentration and ratio of MTMS to sodium silicate, the precursor MTMS could be emulsified to form an emulsion. After drying the coated emulsion on a substrate in air at room temperature, a superhydrophobic coating with water contact angle of 153° was obtained. Scanning electronic microscopy characterization indicates that the coating consists mainly of interconnected sub-100 nm particles from emulsion droplets. During drying, PMSQ formed in the emulsion droplet penetrated the outer surface of the emulsified particle, imparting hydrophobicity and nanoscale roughness to the surface. These roughness and hydrophobic properties resulted in superhydrophobicity of the coating. The process is simple and has potential for large area fabrication of superhydrophobic surfaces. © 2015, American Coatings Association.

Chen J.,Dingxi Teachers College | Chen J.,Zhejiang University | Li C.-G.,Zhejiang University
Wuli Xuebao/Acta Physica Sinica | Year: 2011

The circuit design and implementation of neuron models have attracted much attention in recent years due to its importance in both theoretical studies and applications. In this paper, we designed electronic circuits for the recently proposed tabu learning chaotic neuron model, including the circuit design of single tabu learning neuron, a two-neuron system with linear proximity function, as well as a two-neuron system with quadratic proximity function. We used the electronic workbench (EWB) software to perform simulations of the designed circuits. We also studied the nonlinear behavior, especially the Hopf bifurcation and chaos, of the designed circuits. The consistency between the nonlinear behavior in the designed circuits and that in the numerical simulations demonstrates the correctness of the circuits design. © 2011 Chinese Physical Society.

Liu J.,Northwest Normal University | Du L.,Northwest Normal University | Du L.,Dingxi Teachers College | Zhang J.,Dingxi Teachers College
Journal of Geometry and Physics | Year: 2015

In this paper, we investigate the minimality or the constraint of the mean curvature of three kinds of biharmonic space-like submanifolds in pseudo-Riemannian space forms: (1)pseudo-umbilical ones; (2)the ones with parallel mean curvature vector; (3)with constant mean curvature. © 2015 Elsevier B.V.

Zhang W.,Gansu Agricultural University | Liu F.,Gansu Agricultural University | Yang M.,Gansu Agricultural University | Liang Q.,Gansu Agricultural University | And 3 more authors.
Preparative Biochemistry and Biotechnology | Year: 2014

In order to breed a high-yield β-galactosidase-producing strain, Aspergillus oryzae was used as the parent strain and mutagenized with ultraviolet (UV) and UV plus lithium chloride (LiCl), respectively. After being mutagenized by UV, the β-galactosidase activity of mutant UV-15-20 reached 114.08 U/mL, which revealed a 49.22% increase compared with the original strain. A mutant UV-LiCl-38 with high β-galactosidase activity (121.42U/mL) was obtained after compound mutagenesis of UV and LiCl; the β-galactosidase activity of this mutant was 58.82% higher than that of the parent strain. Subculture testing indicated that UV-15-20 and UV-LiCl-38 had good hereditary stability and may be ideal strains for the production of β-galactosidase. Additionally, it was demonstrated that compound mutagenesis with UV and LiCl is an effective mutation method for breeding industrially interesting strains. © 2014 Copyright Taylor and Francis Group, LLC.

Liu J.,Northwest Normal University | Du L.,Northwest Normal University | Du L.,Dingxi Teachers College
Differential Geometry and its Application | Year: 2015

In this paper, we give some examples of proper biharmonic hypersurfaces in de Sitter space Sqn+1(c) and anti-de Sitter space Hqn+1(c), and prove a classification theorem of nondegenerate proper biharmonic hypersurfaces with diagonalizable shape operator and at most two distinct principal curvatures in pseudo-Riemannian space forms Nqn+1(c). © 2015 Elsevier B.V.

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