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Zhang W.Z.,Northwest Normal University | Zhang W.Z.,Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province | Li J.L.,China Institute of Technology | Fan M.H.,Northwest Normal University | And 3 more authors.
MATEC Web of Conferences | Year: 2016

A novel self-Tracking high-pass filter by using analog multiplier and current feedback op-Amp (CFA) is proposed in this paper. The frequency-voltage (F/V) converter transforms the input pulse signal into the voltage, and then the output of F/V converter controls the cut-off frequency of voltage controlled high-pass filter. Thus, the cut-off frequency of designed filter is linear with the frequency of input signal in case that resistors and capacitors are reasonable adjusted. The experiment and simulation results show that the cut-off frequency of designed filter is 1 kHz-100 kHz. © Owned by the authors, published by EDP Sciences, 2016.


Wut Z.W.,Helmholtz Center for Heavy Ion Research | Wut Z.W.,Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province | Kabachnik N.M.,German Electron Synchrotron | Kabachnik N.M.,Moscow State University | And 4 more authors.
Journal of Physics: Conference Series | Year: 2015

The angular distribution and photon-photon angular correlation have been studied for x-ray emissions from two-step radiative cascades that proceed via two or more overlapping intermediate resonances. From this study, we suggest that accurate angle-resolved measurements of the x-ray emissions may serve as a tool for determining small level splittings in excited highly-charged ions. © Published under licence by IOP Publishing Ltd.


Jia D.-J.,Northwest Normal University | Jia D.-J.,Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province | Zhang J.-H.,Northwest Normal University | Zhang J.-H.,Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province | Wang Q.,Tsinghua University
Chinese Physics C | Year: 2012

The role of the anti-commutator term of the chiral current in a Skyrme-like model was studied associated with the symmetric Skyrmion and the nucleon properties in terms of the zero-mode quantization. It is shown that the Skyrmion is stable only when the anti-commutator term in the model has a negative coupling constant(-k 2) while a QCD functional analysis gives a positive coupling constant. This implies either the coupling is negligibly small and negative, or the soliton picture for the baryons is beyond the approximation of QCD at the level of the quark loop. © 2012 Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Sciences and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.


Jia R.-J.,Northwest Normal University | Wang C.-L.,Northwest Normal University | Yang Y.,Northwest Normal University | Gou X.-Q.,Northwest Normal University | And 3 more authors.
Wuli Xuebao/Acta Physica Sinica | Year: 2013

Locked-to-sliding phase transition is studied based on the two-dimensional Frenkel-Kontorova model in this paper. The method of molecular dynamics simulation is used. The effect of the static friction force on system parameter is investigated numerically when the upper layer atoms are of the hexagon symmetric structure. © 2013 Chinese Physical Society.


Yang Y.,Northwest Normal University | Wang C.-L.,Northwest Normal University | Duan W.-S.,Northwest Normal University | Duan W.-S.,Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province | And 2 more authors.
Wuli Xuebao/Acta Physica Sinica | Year: 2012

In order to better simulate a real model which can be realized in experiment, we study a two-dimensional(2D) Frenkel- Kontorova(FK) model driven by the disordered substrate potential which is charactered by the sum of identical Gaussian functions. Commensurate and incommensurate interfaces are discussed. In the paper, we mainly analyse the mechanism of friction, and the effects of static friction force on the disordered substrate potential. © Chinese Physical Society.


Ma L.-G.,Northwest Normal University | Ma S.-Y.,Northwest Normal University | Ma S.-Y.,Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province | Chen H.-X.,Northwest Normal University | Huang X.-L.,Northwest Normal University
Gongneng Cailiao/Journal of Functional Materials | Year: 2011

The Al-doped ZnO (AZO) thin films with different Al contents were deposited on ZnO buffer layer by reactive RF magnetron sputtering technology.The microstructure, surface morphology, luminescence properties of the AZO thin films were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM)and photoluminescence (PL) spectrum, respectively.The results revealed that the preferred orientation of ZnO films became with increasing Al doping concentration.And as Al doping concentration was 0.81at% the ratio of intensity of (002) to other peaks attained maximum, which indicated that appropriate Al-doping can improve the preferred orientation of ZnO films.The average transmittance was above 70%in the visible range.Two blue peaks located at 444nm (2.80eV) and 483nm (2.57eV) and weak green peak located at about 521nm (2.38eV) were observed from the PL spectra of the four samples and the mechanism of luminescence was discussed.


Zhou M.,Northwest Normal University | Sun A.,Northwest Normal University | Sun A.,Chinese Academy of Sciences | Sun A.,Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province | And 2 more authors.
Superconductor Science and Technology | Year: 2013

A series of polycrystalline YBa2Cu3O 7-δ (YBCO) + x mol% Y2Ba4CuMoO y (Y-24Mo1) (x = 0.00, 0.05, 0.10, 0.20, 0.30, 0.50, 2.00 and 3.00) superconductors have been synthesized in air via a standard solid-state reaction technique. The effects of Y-24Mo1 addition on the microstructure, elemental distribution and the superconducting transition temperature were systematically investigated. When Y-24Mo1 was added to the YBCO, the predominantly single-phase with orthorhombic structure was maintained even at the highest concentration. SEM, EDS and EELS analyses show the presence of inhomogeneities, the change of homogeneity and the variation of oxygen distribution in the superconducting matrix. The Y-24Mo1 addition modifies the normal-state resistivity of samples from metallic to semiconducting, and is accompanied by a two-step transition. Moreover, low Y-24Mo1 concentration leads to a relatively sharp superconducting transition and a broad transition takes place for Y-24Mo1 addition greater than 0.30 mol%. These results can be interpreted by the change of oxygen distribution and by the variation of defects, twins, and oxygen deficiency. © 2013 IOP Publishing Ltd.


Yin Y.-H.,Northwest Normal University | Yin Y.-H.,Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province | Chen H.-S.,Northwest Normal University | Chen H.-S.,Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province
Computational and Theoretical Chemistry | Year: 2016

(MgO)9 with a rocksalt structure, a magic number cluster of (MgO)n, exhibits high stability. In this study, the hydrogen storage properties of (MgO)9 under an external electric field are explored by DFT calculation. The results reveal that H2 can be adsorbed on single Mg/O atoms. Because the (MgO)9 and H2 are effectively polarized by the external electric field, the adsorption strength of H2 at certain adsorption sites is substantially enhanced. The adsorption energies of H2 on three-coordinated Mg/O atoms increase from -0.071/-0.056 eV in the absence of an electric field to -0.186/-0.237 eV under a field intensity of 0.025 a.u. Under the field, (MgO)9 can adsorb a maximum of 18 H2 molecules, and the corresponding mass density of hydrogen storage reaches 9.1 wt%. Our results suggest that subjecting the (MgO)9 to an external electric field is a potential hydrogen storage method. In this paper, the interaction mechanism between H2 and (MgO)9 under the external electric field is also investigated through an electronic structure analysis. © 2016.


Zhou M.,Northwest Normal University | Sun A.,Northwest Normal University | Sun A.,Chinese Academy of Sciences | Sun A.,Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province | And 3 more authors.
Journal of Superconductivity and Novel Magnetism | Year: 2014

Synthesis of polycrystalline YBa2Cu3O 7-δ (YBCO) + x mol.% Y2Ba4CuMoO y (Y-24Mo1) (x=0.0, 0.1, 0.2, 1.0, 2.0 and 20.0) superconductors have been done in air via a standard solid state reaction technique. The effects of Y-24Mo1 particles on the microstructure and the superconducting transition temperature were systematically investigated through XRD and SEM techniques. When Y-24Mo1 was added to the YBCO, the orthorhombic structure maintained even at the highest concentration. Tiny peaks of Y-24Mo1 having (022) orientation and some other impurity were detected in the XRD spectrum when x=20.0. SEM results reveal the presence of some entities, and these entities changed with increase of Y-24Mo1 content. The Y-24Mo1 addition modifies the normal state resistivity of samples from metallic to semiconducting, and is accompanied by a two-step transition. Moreover, low Y-24Mo1 concentration leads to a relatively sharp superconducting transition and a broad transition take place for Y-24Mo1 addition greater than 0.2 mol.%. These results can be induced by the inhomogeneities, by the change of the effective coupling strength, and by the variation of the coupling between grains. © 2013 Springer Science+Business Media New York.


Chen H.,Northwest Normal University | Ding J.,Northwest Normal University | Ma S.,Northwest Normal University | Ma S.,Key Laboratory of Atomic and Molecular Physics and Functional Materials of Gansu Province
Superlattices and Microstructures | Year: 2011

Pure and Ti-doped zinc oxide (TZO) films are deposited using radio frequency (RF) reactive magnetron sputtering at different RF powers. Micro-structural and optical properties in doped ZnO films are systematically investigated by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electronic microscopy (SEM), and a fluorescence spectrophotometer. The results indicate that ZnO films show stronger preferred orientation toward the c-axis and smoother surface roughness after Ti doping. As for TZO films, the full width at half maxima (FWHM) of (002) diffraction peaks decreased first and then increased, reaching a minimum of about 0.92° at 150 W, while the residual compressive stress of the TZO film prepared at 150 W became the largest. The photoluminescent (PL) spectra measured at room temperature reveal a violet, a blue and two green emissions. Intense violet and blue-green luminescence is obtained for the sample deposited at higher RF power. The origin of these emissions is discussed. © 2010 Elsevier Ltd. All rights reserved.

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