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Achieving enhanced energy storage performance and ultra-fast discharge time in tungsten–bronze ceramic
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作者 Yuejun Dan Liupan Tang +4 位作者 Wenzhi Ning Yingzhi Meng Changzheng Hu Laijun Liu Liang Fang 《Journal of Advanced Ceramics》 SCIE EI CAS CSCD 2024年第9期1349-1358,共10页
The rapid development of capacitors with high energy density and efficiency has been driven by advanced electronic systems and innovative pulsed power applications.In this study,we prepared Sr_(4.5−x)Ba_(x)Sm_(0.5)Zr_... The rapid development of capacitors with high energy density and efficiency has been driven by advanced electronic systems and innovative pulsed power applications.In this study,we prepared Sr_(4.5−x)Ba_(x)Sm_(0.5)Zr_(0.5)Nb_(9.5)O_(30)(x=2.5,3,3.5,4,4.5)dielectric ceramics,which exhibited structural distortion due to the co-occupation of Ba^(2+),Sr^(2+),and Sm^(3+)in the A-site and the partial substitution of Nb^(5+)by Zr^(4+)in the B-site.The ordered/disordered distribution due to these distortions thus generated polar nanoregions(PNRs)and induced a relaxation ferroelectric behavior,which was verified by the high-resolution transmission electron microscopy.Through the use of the Vogel–Fulcher and Maxwell–Boltzmann equations,we found that easy inversion and small dipole sizes are crucial for achieving high energy storage density and efficiency.The Sr_(4.5−x)Ba_(x)Sm_(0.5)Zr_(0.5)Nb_(9.5)O_(30)(x=3.5)dielectric ceramic displayed a ferroelectric/paraelectric transition near room temperature.Subsequent ferroelectric testing revealed large energy storage density(Wrec=4.31 J·cm^(−3))and high efficiency(η=93.8%)at 310 kV·cm−1.Furthermore,Sr_(4.5−x)Ba_(x)Sm_(0.5)Zr_(0.5)Nb_(9.5)O_(30)(x=4.5)exhibited higher breakdown field strength due to its large resistivity and small grain size.This led to energy storage density of approximately 5.3 J·cm^(−3)at 460 kV·cm^(−1).Additionally,Sr_(4.5−x)Ba_(x)Sm_(0.5)Zr_(0.5)Nb_(9.5)O_(30)(x=3.5)demonstrated current density(CD)of approximately 713.38 A·cm^(−2)and power density(PD)of approximately 87.51 MW·cm^(−3),with ultrafast discharge time of 34 ns and excellent discharge energy density(Wdis)of approximately 2.27 J·cm^(−3).Overall,this study presents a promising approach for developing dielectric ceramic materials that hold potential for applications in innovative pulsed power components. 展开更多
关键词 large energy storage high efficiency ultra-fast discharge time tungsten-bronze structure
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Time-resolved measurements of NO2 concentration in pulsed discharges by high-sensitivity cavity ring-down spectroscopy 被引量:1
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作者 吴兴伟 李聪 +2 位作者 冯春雷 王奇 丁洪斌 《Plasma Science and Technology》 SCIE EI CAS CSCD 2017年第5期80-84,共5页
To describe the complex kinetics of formation and destruction mechanism of nitrogen dioxide(NO2), there is an increasing demand for real-time and in situ analysis of NO2 in the discharge region. Pulsed cavity ring-d... To describe the complex kinetics of formation and destruction mechanism of nitrogen dioxide(NO2), there is an increasing demand for real-time and in situ analysis of NO2 in the discharge region. Pulsed cavity ring-down spectroscopy(CRDS) provides an excellent diagnostic approach. In the present paper, CRDS has been applied in situ for time evolution measurement of NO2 concentration which is rarely investigated in gas discharges. In pulsed direct current discharge of NO2/Ar mixture at a pressure of 500 Pa, a peak voltage of -1300 V and a frequency of 30 Hz, for higher initial NO2 concentration(3.05×10^(14)cm^(-3), 8.88×10^(13)cm^(-3)),the NO2 concentration sharply decreases at the beginning of the discharge afterglow and then becomes almost constant, and the pace of decline increases with pulse duration; however, for lower initial NO2 concentration of 1.69×10^(13)cm^(-3), the NO2 concentration also decreases at the beginning of the discharge afterglow for 200 ns and 1 μs pulse durations, while it slightly increases and then declines for 2 μs pulse duration. Thus, the removal of low-level NO2 could not be promoted by a higher mean energy input. 展开更多
关键词 CRDS ns-pulsed discharge time evolution of NO2 concentration
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Kinetic effects of nanosecond discharge on ignition delay time
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作者 Xingqian Mao Guoxiu Li +1 位作者 Qi Chen Yujun Zhao 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2016年第12期1719-1727,共9页
The effects of nanosecond discharge on ignition characteristics of a stoichiometric methane–air mixture without inert diluent gas were studied by numerical simulation at 0.1 MPa and an initial temperature of 1300 K. ... The effects of nanosecond discharge on ignition characteristics of a stoichiometric methane–air mixture without inert diluent gas were studied by numerical simulation at 0.1 MPa and an initial temperature of 1300 K. A modified non-equilibrium plasma kinetic model was developed to simulate the temporal evolution of particles produced during nanosecond discharge and its afterglow. As important roles in ignition, path fluxes of O and H radicals were analyzed in detail. Different strength of E/N and different discharge duration were applied to the discharge process in this study. And the results presented that a deposited energy of 1–30 m J·cm^(-3) could dramatically reduce the ignition delay time. Furthermore, temperature and radicals analysis was conducted to investigate the effect of non-equilibrium plasma on production of intermediate radicals. Finally, sensitivity analysis was employed to have further understanding on ignition chemistries of the mixture under nanosecond discharge. 展开更多
关键词 Nanosecond discharge Ignition delay time Methane Kinetic modeling Numerical simulation
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Analytical model for describing ion guiding through capillaries in insulating polymers
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作者 刘世东 赵永涛 +5 位作者 王瑜玉 Stolterfoht N 程锐 周贤明 徐瑚珊 肖国青 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第8期457-462,共6页
An analytical description for guiding of ions through nanocapillaries is given on the basis of previous work. The current entering into the capillary is assumed to be divided into a current fraction transmitted throug... An analytical description for guiding of ions through nanocapillaries is given on the basis of previous work. The current entering into the capillary is assumed to be divided into a current fraction transmitted through the capillary, a current fraction flowing away via the capillary conductivity and a current fraction remaining within the capillary, which is responsible for its charge-up. The discharging current is assumed to be governed by the Frenkel–Poole process. At higher conductivities the analytical model shows a blocking of the ion transmission, which is in agreement with recent simulations.Also, it is shown that ion blocking observed in experiments is well reproduced by the analytical formula. Furthermore, the asymptotic fraction of transmitted ions is determined. Apart from the key controlling parameter(charge-to-energy ratio), the ratio of the capillary conductivity to the incident current is included in the model. Differences resulting from the nonlinear and linear limits of the Frenkel–Poole discharge are pointed out. 展开更多
关键词 ion guiding charging and discharging time blocked transmission asymptotic transmission
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Coal combustion restrained by ultra-fine water mist in confined space 被引量:1
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作者 YU Ming-gao YANG Ke +2 位作者 JIA Hai-lin LU Chang LU Lai-xiang 《Mining Science and Technology》 EI CAS 2009年第5期574-579,共6页
In order to apply ultra-fine water mist technology on spontaneous coal combustion in the goaf of a coal mine, we built a small scale compartment with ultra-fine water mist for restraining coal combustion in a confined... In order to apply ultra-fine water mist technology on spontaneous coal combustion in the goaf of a coal mine, we built a small scale compartment with ultra-fine water mist for restraining coal combustion in a confined space and then investigated the restraining efficiency and related factors. The study obtained the following results: a descending rate of heat release, an increase in 02, the production of CO2 decreased gradually, while the production of CO increased dramatically and quickly and then decreased; ultimately it tended to become stable after the discharge of an ultra-fine water mist. The technology showed that the ultra-fine water mist can effectively reduce the heat release rate of coal and the rate to generate components. We found that the restraining effect relied on the mist flux, the discharge time and other factors. A sufficient amount of mist has a better effect compared to an insufficient amount of mist. To combat coal combustion, the greater the discharge time, the better coal flames are extinguished. 展开更多
关键词 ultra-fine water mist coal combustion mist flux discharge time
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Experimental Study on Triggering Characteristics of a Surface Flashover Triggered Vacuum Switch 被引量:1
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作者 姚学玲 陈景亮 孙伟 《Plasma Science and Technology》 SCIE EI CAS CSCD 2010年第6期734-737,共4页
Triggering characteristics of triggered vacuum switch (TVS), including the discharge delay time, delay jitter, range of operational voltage and peak of pulsed current, are investigated. Both structure and experiment... Triggering characteristics of triggered vacuum switch (TVS), including the discharge delay time, delay jitter, range of operational voltage and peak of pulsed current, are investigated. Both structure and experimental circuit of TVS are presented. The results indicate that TVS, as a surface flashover triggering device with high dielectric permittivity material, is with excellent triggering characteristics. When the hold-off voltage reaches 120 kV, the minimum operational voltage is 1.3 kV, and the minimum discharge delay time and jitter are 100 ns and ±10 ns, respectively. The peak current is up to 240 kA when the operational voltage reaches 100 kV. TVS can well satisfy the main demands of high voltage and current applications, and can also be used under a multi-crowbar circuit. 展开更多
关键词 surface flashover dielectric material TVS(triggered vacuum switch) discharge delay time delay jitter
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Effects of Xe Gas Content and Total Gas Pressure on the Discharge Characteristics of Colour Plasma Display Panels
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作者 胡文波 韩梦驹 梁志虎 《Plasma Science and Technology》 SCIE EI CAS CSCD 2006年第4期447-450,共4页
The effects of the Xe gas content and total gas pressure on the discharge characteristics of colour plasma display panels including the sustaining voltage margin, white-field chromaticity, discharge time lag (DTL), ... The effects of the Xe gas content and total gas pressure on the discharge characteristics of colour plasma display panels including the sustaining voltage margin, white-field chromaticity, discharge time lag (DTL), discharge current peak, and full-width-at-half-maximum (FWHM) of the discharge current pulse, are experimentally studied. The results indicate that as the Xe gas content in the He-Ne-Xe gas mixture or total pressure increases, the sustaining voltage margin increases, the white-field chromaticity improves, and the discharge current peak has a maximum value, while DTL and FWHM have a minimum value. The mean electron energy in the gas mixture discharge is also calculated through a numerical solution of Boltzmann equation. The experimental results are explained from a view of the mean electron energy variations with the Xe gas content and total gas pressure. 展开更多
关键词 plasma display panel gas mixture discharge characteristic sustaining voltage margin discharge time lag
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Analysis of low energy arc discharge characteristics based on dynamic V-A characteristics model
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作者 井莉楠 王立功 《Journal of Coal Science & Engineering(China)》 2006年第2期91-93,共3页
Low energy arc discharge characteristics was analyzed based on dynamic V-A characteristics model. It draws conclusions that discharge time relates to the source voltage and the product of inductance and stable current... Low energy arc discharge characteristics was analyzed based on dynamic V-A characteristics model. It draws conclusions that discharge time relates to the source voltage and the product of inductance and stable current, discharge time will increase when the source voltage increases; current reduce rate is in inverse proportion to the value of inductance; arc resistance when the arc occurs is the ratio of minimum arcing voltage to stable current. It also gains the expressions of arc resistance and arc power, arc resistance and arc power both increase as the source voltage increases and decrease as the value of inductance increases. Conclusions above mentioned are helpful to design intrinsically safe circuits. 展开更多
关键词 intrinsically safe circuit discharge time arc resistance arc power
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