BingZhou University

China

BingZhou University

China
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Li Y.X.,Nanyang Normal University | Zhou S.,Nanyang Normal University | Zhao F.J.,BingZhou University | Liu Y.,Wuhan University of Science and Technology | And 2 more authors.
Brazilian Journal of Oceanography | Year: 2010

In the present study, several physiological responses of the red marine alga Porphyra haitanesis to elevated concentrations of copper (up to 50 μM) and zinc (up to 100 μM) were investigated. Our results showed that the effects of Cu2+ and Zn2+ on growth, photosynthetic pigments (chlorophylls and carotenoids), phycobiliprotein and metabolism (the fluorescence emission spectra and the activities of photosystem II) did not follow the same pattern. The relative growth rate was inhibited by different concentrations of Cu2+, and was slightly increased at lower concentrations (up to 10 μM) and inhibited at higher Zn2+concentrations. On the other hand, the phycoerythrin contents were slightly increased at relatively low concentrations (up to 1 μM Cu2+ or 20 μM Zn2+) and inhibited by high Cu2+ and Zn2+ concentrations. Moreover, photosynthesis and respiration showed an increase in the amount of oxygen exchange in response to relatively low Cu2+ (up to 1 μM) and Zn2+ concentrations (up to 10 μM), and a reduction to relatively high Cu2+ and Zn2+ concentrations. Oxygen evolution was more sensitive than oxygen uptake to Cu2+ and Zn2+. In addition, the photoreductive activities and fluorescence emission of photosystem II (PS II) were enhanced by lower concentrations of Cu2+ (up to 0.1 μM) and Zn2+ (up to 10 μM) and inhibited by higher concentrations. Furthermore, the intensity of chlorophyll a fluorescence and the active PSII reaction centers followed a similar pattern in response to elevated concentrations of Cu2+ and Zn2+. These results suggest that lower concentrations of Cu2+ and Zn2+ affected the metabolism of P. haitanesis, which was inhibited by higher concentrations of these metals.


Ji Y.,Bingzhou University | Du Y.,Bingzhou University | Du Y.,Nanjing Institute of Technology | Wang M.,Ludong University
Optik | Year: 2014

The electronic structure of wurtzite GaN doped with Si was calculated using the first-principles plane-wave pseudopotential method, based on the density function theory. The results show that GaN doped with Si is n-type semiconductor with direct band-gap, band gap increases, compared with that of undoped GaN. The doped system was sectioned in (0 0 0 1) and (0 0 0 1̄) direction. (0 0 0 1̄) surface has larger change in morphology than (0 0 0 1) surface, and is against the escape of electrons. The electronic non-locality of (0 0 0 1) surface is enhanced. The electronic structure and optical properties of GaN(0 0 0 1) surface with Si doping were analyzed and compared with those of undoped surface. The studies show that the absorption to visible light enhances, absorption to ultraviolet light abates. Dopedsurface is fit for ultraviolet detection. © 2013 Elsevier GmbH. All rights reserved.


Ji Y.-J.,Bingzhou University | Du Y.-J.,Bingzhou University | Du Y.-J.,Nanjing University of Science and Technology | Wang M.-S.,Ludong University
Optik | Year: 2016

Using first-principles method, we studied the electronic structures, work functions and electron affinities of the GaN(0001), Ga(Mg)N(0001), AlGa(Mg)N(0001), and Cs adsorbed AlGa(Mg)N(0001) surfaces. A method was offered to calculate the surface electron affinity using work function. The results show that Al 3s has a strong appeal to N 2s, which enhances the orbital hybridization of Mg s and N p states, and increases doping concentration. The interaction between Mg and N atoms enhanced by Al doping leads to the increase of surface dipole moment. AlGa(Mg)N(0001)'s work function is the smallest in comparison with that of GaN(0001) and GaMgN(0001) surfaces. After Cs adsorption on AlGa(Mg)N(0001) surface, the transfer of Cs6s electrons to Ga atoms in the outermost layer enhances the dipole moment pointing to outside and decreases the work function of the system, the negative electron affinity achieves. © 2016 Elsevier GmbH. All rights reserved.


Ji Y.,Bingzhou University | Du Y.,Bingzhou University | Du Y.,Nanjing University of Science and Technology | Wang M.,Ludong University
Optik | Year: 2014

The electronic structures and optical properties of In doped GaN were calculated with different doping concentration, from first-principles using density function theory with the plane-wave ultrasoft pseudopotential method. The influence of In doping on the volume, interactions among atoms, density of states, electron density difference, and optical properties of GaN was analyzed. The results show that the interactions among atoms are reduced, band gap decreases, and absorption spectra have red shift along with the increase of In doping concentration. © 2014 Elsevier GmbH. All rights reserved.


Ji Y.-J.,Bingzhou University | Du Y.-J.,Bingzhou University | Wang M.-S.,Ludong University
Chinese Physics B | Year: 2013

The electronic structure and optical properties of Al and Mg co-doped GaN are calculated from first principles using density function theory with the plane-wave ultrasoft pseudopotential method. The results show that the optimal form of p-type GaN is obtained with an appropriate Al:Mg co-doping ratio rather than with only Mg doping. Al doping weakens the interaction between Ga and N, resulting in the Ga 4s states moving to a high energy region and the system band gap widening. The optical properties of the co-doped system are calculated and compared with those of undoped GaN. The dielectric function of the co-doped system is anisotropic in the low energy region. The static refractive index and reflectivity increase, and absorption coefficient decreases. This provides the theoretical foundation for the design and application of Al - Mg co-doped GaN photoelectric materials. © 2013 Chinese Physical Society and IOP Publishing Ltd.

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