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Li Y.,Hebei United University | Wang R.,Tianjin Maritime Vocational Institute | Ma X.,Hebei United University | Li Z.,Shijiazhuang University | And 2 more authors.
Materials Research Bulletin | Year: 2014

The dielectric properties and phase transition of Sm3+-doped BaZr0.2Ti0.8O3 (BZT20) ceramics were investigated. Room temperature X-ray diffraction study suggested that the compositions had single-phase cubic symmetry. Microstructure studies showed that the grain size decreased and that the Sm2O3 amount markedly affected the dielectric properties of BZT20. A dielectric constant of 5700 at 0.2 mol% Sm2O3 and a dissipation factor of only 0.0011 at 2 mol% Sm2O3 were observed, indicating that BZT20 had significant potential applications. Moreover, the dielectric constant, dissipation factor, phase-transition temperature, and maximum dielectric constant increased with increased Sm2O3 amount at ≤0.2 mol% Sm2O3 but decreased with increased Sm 2O3 amount at >0.2 mol% Sm2O3. © 2013 Elsevier Ltd. All rights reserved.


Li Y.,Hebei Polytechnic University | Qu Y.,Tianjin University of Technology | Zhang Q.,Hebei Polytechnic University | Wang R.,Tianjin Maritime Vocational Institute
Advanced Materials Research | Year: 2011

Ba0.62Sr0.38TiO3 ceramics of perovskite structure are prepared by solid reaction method with the addition of x wt% NiO and their dielectric properties are investigated. It is found that Ni 2+ can enter the B site in ABO3 perovskite when doping concentration is less than 0.6 wt%, whereafter, Ni2+ ions most segregates on the grain boundaries to inhabit the grain growth. Due to the decrease of grain size and the impurity, the dielectric constants are decreased. Decrease of dissipation factor is attributed to appearance of the oxygen vacancy and disappearance of the reduction of Ti4+ ion. It is concluded that the diffuse phase transition is linked to the adulteration of Ni2+. The disordering, mechanical stress in the grain and the oxygen vacancies are produced because of the adulteration of Ni2+, and the diffuse phase transition increases with the level of doping increasing, leading to that the peaks of dielectric constants becomes slower and flatter.


Li Y.,Hebei United University | Ma X.,Hebei United University | Li Z.,Shijiazhuang University | Wang R.,Tianjin Maritime Vocational Institute | And 2 more authors.
Ceramics International | Year: 2013

The dielectric properties and phase transition of Sm3+-doped BaSn0.1Ti0.9O3 (BTS10) ceramics were investigated. The amount of Sm2O3 greatly affected the dielectric properties of BTS10. A dielectric constant of 5500 with 0.6 mol% Sm2O3 and a dissipation factor of only 0.005 with 0.1 mol% Sm2O3 were assessed. The variation in the dielectric constant indicated that Sm3+ ion is mainly substituted for the A-site ions when x≤0.6 mol%, whereas it is mainly substituted for B-site ions when x exceeded 0.6 mol%. Meanwhile, the variation in the dissipation factor showed that a very small amount of Sm3+ occupied the B site when x≤0.1 mol%. The materials showed relaxor-like behaviour with a diffuse-type ferroelectric phase transition. The diffusivity increased when the amount of Sm2O3 is increased, which also implied that there should be a very small amount of Sm3+ occupying the B site when x≤0.1 mol%. © 2012 Elsevier Ltd and Techna Group S.r.l.


Li Y.,Hebei Polytechnic University | Li Y.,Tianjin University of Technology | Zhang Q.,Hebei Polytechnic University | Qu Y.,Tianjin University of Technology | Wang R.,Tianjin Maritime Vocational Institute
Yadian Yu Shengguang/Piezoelectrics and Acoustooptics | Year: 2011

The Ba(Zr0.2Ti0.8)O3 ceramics were prepared using BaCO3, ZrO2 and TiO2 et al as crude materials, Sm2O3 as dopant, and the dielectric properties are investigated. The morphology of the samples was observed by SEM. It was found that the Sm3+ ions tended to enter into the B-site in the perovskit lattice with the amount of the dopants increase when the amount of x(Sm2O3) was less than 0.2% and after the Sm3+ ions entered into the A-site. The amount of Sm2O3-dopant has significantly influence on the dielectric constant and the loss of the sample. When the amount of x(Sm2O3) was 0.2%, the ceramic sample had the maximum dielectric constant of about 5600. With the amount of Sm2O3-dopant increase, the dielectric loss of the sample has been improved significantly and the minimum loss has decreased to 0.0021.


Li Y.,Hebei United University | Ma X.,Hebei United University | Wang R.,Tianjin Maritime Vocational Institute | Cui Z.,Hebei United University | And 3 more authors.
Advanced Materials Research | Year: 2012

Ba(Ti 0.95Sn 0.05) O 3 ceramics were prepared using BaCO 3, SnO 2 and TiO 2 et al as crude materials, La 2O 3 as dopant, and their dielectric properties are investigated. The morphology analysis of sintered samples was conducted by SEM. It is found that for 0.1 wt% La 2O 3 doped BTS5 ceramics sintered at 1290°C has the highest dielectric constant. It can also be seen that the samples sintered at 1260°C have higher dielectric loss, which can result from the existence of the pore. Meanwhile, in the terms of dielectric loss, 0.1 wt% La 2O 3 doped BTS5 ceramics has lower value and the dielectric loss is more stable with temperature varying. © (2012) Trans Tech Publications.


Ma J.-C.,Tianjin Maritime Vocational Institute | Ma J.-C.,Tianjin University | Zhang Z.-G.,Tianjin Maritime Vocational Institute | Zhao J.,Tianjin University
Shuidonglixue Yanjiu yu Jinzhan/Chinese Journal of Hydrodynamics Ser. A | Year: 2014

A three-dimension physical simulation experiment of infiltration sand box is conducted, which, combining with related theories of colloid and surface chemistry, in meso scale, explicated the induced mechanism of the aquifer medium clay particle redistribution in different modes, and then probed into the variation in space structure of the brackish aquifer medium in complex space-time conditions. The results show that the brackish aquifer permeability is influenced by the temperature as well as as the salinity variation of recharged solution and that the permeability and heat transfer capability changes of aquifer medium are heterogeneous obviously in horizontal and vertical direction. In the heat storage experiment of recharged low salty mixed solution, the relative permeability of upper layer aquifer medium is decreased to 53% in the 500 mm-700 mm seepage element and the temperature is up to 45°C. However, the relative permeability of lower layer aquifer medium is finally decreased to 48% and the temperature increased slightly and been up to 42.9°C from 15°C at the end of the experiment.


Zhang S.-H.,Beijing University of Technology | Zhang S.-H.,Tianjin Maritime Vocational Institute | Wu L.-S.,Beijing University of Technology | Zhou D.-S.,Beijing University of Technology | Qu C.-N.,Beijing University of Technology
Beijing Gongye Daxue Xuebao/Journal of Beijing University of Technology | Year: 2012

Based on the online dynamic balance device principle, the design method of the embedded double-face online dynamic device is proposed. The balance disks can be disengaged from the spindle through a hydraulic system, and the rotation speed of the disengaged disks is kept steady and under the speed of the spindle through a friction torque. The system realization of signal acquisition, signal analysis and control, and hydraulic pressure are designed. The feasibility is proved by examples.


Zhang S.-H.,Beijing University of Technology | Zhang S.-H.,Tianjin Maritime Vocational Institute | Wu L.-S.,Beijing University of Technology | Qu C.-N.,Beijing University of Technology
Zhendong yu Chongji/Journal of Vibration and Shock | Year: 2012

The Empirical Mode Decomposition (EMD) is used for decomposing nonstationary and nonlinear signals to stationary and linear ones, and Intrinsic Mode Functions (IMFs) can be gained, they contain only a single group of frequencies. In order to reduce interference of abnormal events to the EMD method, the correlation analysis was used to eliminate abnormal events. The method to separate rotor imbalance vibration signals accurately was put forward based on EMD method and imbalance vibration theories, it could be used to monitor imbalance vibration and dynamic balancing. The validity of the proposed method was verified with example analysis.


Teng X.B.,Dalian University | Teng X.B.,Tianjin Maritime Vocational Institute | Zhang J.D.,Dalian University | Zhang S.H.,Tianjin Maritime Vocational Institute | Wang R.R.,Tianjin Maritime Vocational Institute
Advanced Materials Research | Year: 2011

Based on the complexity of surface vibration of diesel engine, the wavelet denoising method is used to process the monitor signal Preliminary. And then several vibration modes are isolated based on EMD method. Finally take the energy of these vibration modes as the input parameters to create neural network for fault diagnosis of diesel engine valve. The method has accomplished the fault diagnosis of the diesel engine merging many methods. © (2011) Trans Tech Publications.

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