期刊文献+
共找到10篇文章
< 1 >
每页显示 20 50 100
环形截面氙灯的放电特性与泵浦效率实验研究 被引量:5
1
作者 杨泽锋 李兴文 +3 位作者 莫永鹏 贾申利 刘建军 李海兵 《强激光与粒子束》 EI CAS CSCD 北大核心 2015年第9期111-115,共5页
针对脉冲氙灯的结构,探索了一种新型的环形截面氙灯以获得更高的泵浦效率。环形截面氙灯内嵌空气玻璃管,拥有中空的新结构,对脉冲氙灯放电特性产生了新的影响,进一步影响了泵浦效率。实验对比了传统氙灯和环形截面氙灯的放电特性、... 针对脉冲氙灯的结构,探索了一种新型的环形截面氙灯以获得更高的泵浦效率。环形截面氙灯内嵌空气玻璃管,拥有中空的新结构,对脉冲氙灯放电特性产生了新的影响,进一步影响了泵浦效率。实验对比了传统氙灯和环形截面氙灯的放电特性、辐射以及钕玻璃的荧光输出。实验结果表明:新型的环形截面氙灯拥有较高的电阻,较低的放电电流与进灯能量,辐射效率和钕玻璃荧光输出分别提高了3%~4%和2%~3%。 展开更多
关键词 环形截面氙灯 电流面密度 能量 辐射 荧光输出
下载PDF
Z箍缩丝阵负载区域的似稳态磁场分布 被引量:1
2
作者 薛创 宁成 +5 位作者 张扬 肖德龙 孙顺凯 黄俊 丁宁 束小建 《强激光与粒子束》 EI CAS CSCD 北大核心 2011年第9期2391-2395,共5页
将负载区域的电流(丝阵电流、阴极板电流、阳极板电流和回流柱电流)离散成电流线或电流面等电流微元,根据毕奥-萨伐尔定律,计算所有电流微元在指定场点的磁场,再通过叠加给出该点的总磁场。研究结果发现:在丝阵外围区域,仅由丝阵电流所... 将负载区域的电流(丝阵电流、阴极板电流、阳极板电流和回流柱电流)离散成电流线或电流面等电流微元,根据毕奥-萨伐尔定律,计算所有电流微元在指定场点的磁场,再通过叠加给出该点的总磁场。研究结果发现:在丝阵外围区域,仅由丝阵电流所产生的磁场偏离无限长直导线磁场公式的值,但全部电流所产生的总磁场与公式给出的值很接近。同时,研究了不同负载结构参数下的磁场分布,结果表明:增加丝根数有助于减小单根丝表面的局部磁场,改善丝阵外围磁场分布的均匀性。 展开更多
关键词 Z箍缩 丝阵 电流线 电流面密度 磁场分布
下载PDF
Effects of mask wall angle on matrix-hole shape changes during electrochemical machining by mask 被引量:8
3
作者 李冬林 朱荻 +1 位作者 李寒松 刘金国 《Journal of Central South University》 SCIE EI CAS 2011年第4期1115-1120,共6页
The influences of the mask wall angle on the current density distribution,shape of the evolving cavity and machining accuracy were investigated in electrochemical machining(ECM) by mask.A mathematical model was develo... The influences of the mask wall angle on the current density distribution,shape of the evolving cavity and machining accuracy were investigated in electrochemical machining(ECM) by mask.A mathematical model was developed to predict the shape evolution during the ECM by mask.The current density distribution is sensitive to mask wall angle.The evolution of cavity is determined by the current density distribution of evolving workpiece surface.The maximum depth is away from the center of holes machined,which leads to the island appearing at the center of cavity for mask wall angles greater than or equal to 90°(β≥90°).The experimental system was established and the simulation results were experimentally verified.The results indicate that the simulation results of cavity shape are consistent with the actual ones.The experiments also show that the repetition accuracy of matrix-hole for β≥90° is higher than that for β<90°.A hole taper is diminished,and the machining accuracy is improved with the mask wall angle increasing. 展开更多
关键词 electrochemical machining matrix-hole machining accuracy current density distribution
下载PDF
One-dimensional Dynamic Modeling and Simulation of a Planar Direct Internal Reforming Solid Oxide Fuel Cell 被引量:2
4
作者 康英伟 李俊 +3 位作者 曹广益 屠恒勇 李箭 杨杰 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2009年第2期304-317,共14页
This article aims to investigate the transient behavior of a planar direct internal reforming solid oxide fuel cell (DIR-SOFC) comprehensively. A one-dimensional dynamic model of a planar D1R-SOFC is first developed... This article aims to investigate the transient behavior of a planar direct internal reforming solid oxide fuel cell (DIR-SOFC) comprehensively. A one-dimensional dynamic model of a planar D1R-SOFC is first developed based on mass and energy balances, and electrochemical principles. Further, a solution strategy is presented to solve the model, and the International Energy Agency (IEA) benchmark test is used to validate the model. Then, through model-based simulations, the steady-state performance of a co-flow planar DIR-SOFC under specified initial operating conditions and its dynamic response to introduced operating parameter disturbances are studied. The dynamic responses of important SOFC variables, such as cell temperature, current density, and cell voltage are all investigated when the SOFC is subjected to the step-changes in various operating parameters including both the load current and the inlet fuel and air flow rates. The results indicate that the rapid dynamics of the current density and the cell voltage are mainly influenced by the gas composition, particularly the H2 molar fraction in anode gas channels, while their slow dynamics are both dominated by the SOLID (including the PEN and interconnects) temperature. As the load current increases, the SOLID temperature and the maximum SOLID temperature gradient both increase, and thereby, the cell breakdown is apt to occur because of excessive thermal stresses. Changing the inlet fuel flow rate might lead to the change in the anode gas composition and the consequent change in the current density distribution and cell voltage. The inlet air flow rate has a great impact on the cell temperature distribution along the cell, and thus, is a suitable manipulated variable to control the cell temperature. 展开更多
关键词 solid oxide fuel cell direct internal reforming PLANAR dynamic model SIMULATION
下载PDF
HIGH EMISSION PERFORMANCE IMPREGNATED DISPENSER CATHODE
5
作者 Yin Shengyi Peng Zhen +1 位作者 Zheng Qiang Wang Yu 《Journal of Electronics(China)》 2013年第4期417-422,共6页
In order to obtain higher emission performance than that of a traditional M-type cathode, we have developed a new type impregnated dispenser cathode. The new cathode is impregnated with a new active substance with mol... In order to obtain higher emission performance than that of a traditional M-type cathode, we have developed a new type impregnated dispenser cathode. The new cathode is impregnated with a new active substance with molar ratio of 26BaO·29SrO·8Sc2O3 ·7CaO·Al2O3 . This paper introduces the emission performance, surface active material, and work function of the new cathode. At 1100℃B , the DC current density and pulse current density are 30.6±1.0 A/cm2 and 171.6±2.8 A/cm2 , respectively, 2.1 and 5.4 times of that of an M-type cathode. The work function of the new cathode is 1.668± 0.002 eV. High concentration O-Al-Sc-Sr-Ba and O-Al-Sc-Ba are found in the pores and at pore edges, respectively. By comparing the emission performances and surface characteristics of as-polished and as-cleaned cathodes, it is proposed that, the emission around pore ends forms the major part of the total emission for the new cathodes. 展开更多
关键词 Dispenser cathode M-type cathode Sc2O3 SRO Emission performance
下载PDF
Supercapacitors based on high-surface-area graphene 被引量:6
6
作者 ZHOU XiaoLin WANG Min +1 位作者 LIAN Jie LIAN YongFu 《Science China(Technological Sciences)》 SCIE EI CAS 2014年第2期278-283,共6页
Exfoliated graphite oxide was prepared by an improved Hummers method and was then reduced to graphene with hydrazine in the presence of ammonium hydroxide.N2adsorption–desorption measurement showed that graphene so o... Exfoliated graphite oxide was prepared by an improved Hummers method and was then reduced to graphene with hydrazine in the presence of ammonium hydroxide.N2adsorption–desorption measurement showed that graphene so obtained had a specific surface area as high as 818 m2/g.Galvanostatic charge/discharge curves demonstrated that the as-prepared graphene exhibited a specific capacitance of 186.9 F/g at a current density of 0.1 A/g and that about 96%of the specific capacitance was retained after 2000 cycles at a current density of 5 A/g. 展开更多
关键词 SUPERCAPACITOR GRAPHENE high specific surface area high specific capacitance
原文传递
In situ construction of heterostructured bimetallic sulfide/phosphide with rich interfaces for high-performance aqueous Zn-ion batteries 被引量:2
7
作者 Fang Yang Yuenian Shen +5 位作者 Ze Cen Jie Wan Shijie Li Guanjie He Junqing Hu Kaibing Xu 《Science China Materials》 SCIE EI CAS CSCD 2022年第2期356-363,共8页
It is still challenging to develop suitable cathode structures for high-rate and stable aqueous Zn-ion batteries.Herein,a phosphating-assisted interfacial engineering strategy is designed for the controllable conversi... It is still challenging to develop suitable cathode structures for high-rate and stable aqueous Zn-ion batteries.Herein,a phosphating-assisted interfacial engineering strategy is designed for the controllable conversion of NiCo_(2)S_(4) nanosheets into heterostructured NiCoP/NiCo_(2)S_(4) as the cathodes in aqueous Zn-ion batteries.The multicomponent heterostructures with rich interfaces can not only improve the electrical conductivity but also enhance the diffusion pathways for Zn-ion storage.As expected,the NiCoP/NiCo_(2)S_(4) electrode has high performance with a large specific capacity of 251.1 mA h g^(−1) at a high current density of 10 A g^(−1) and excellent rate capability(retaining about 76%even at 50 A g^(−1)).Accordingly,the Zn-ion battery using NiCoP/NiCo_(2)S_(4) as the cathode delivers a high specific capacity(265.1 mA h g^(−1) at 5 A g^(−1)),a long-term cycling stability(96.9%retention after 5000 cycles),and a competitive energy density(444.7W h kg^(−1) at the power density of 8.4 kW kg^(−1)).This work therefore provides a simple phosphating-assisted interfacial engineering strategy to construct heterostructured electrode materials with rich interfaces for the development of high-performance energy storage devices in the future. 展开更多
关键词 PHOSPHATING HETEROSTRUCTURE NiCoP/NiCo2S4 Znion batteries high capacity
原文传递
Activated pyrolysed bacterial cellulose as electrodes for supercapacitors 被引量:3
8
作者 Xiangjun Wang Debin Kong +2 位作者 Bin Wang Yan Song Linjie Zhi 《Science China Chemistry》 SCIE EI CAS CSCD 2016年第6期713-718,共6页
In this paper, the bacterial celluloses(BCs) were pyrolysed in nitrogen and then activated by KOH to form a porous three- dimension-network electrode material for supercapacitor applications. Activated pyrolysed bacte... In this paper, the bacterial celluloses(BCs) were pyrolysed in nitrogen and then activated by KOH to form a porous three- dimension-network electrode material for supercapacitor applications. Activated pyrolysed bacterial cellulose(APBC) samples with enlarged specific surface area and enhanced specific capacitances were obtained. In order to optimize electrochemical properties, APBC samples with different alkali-to-carbon ratios of 1, 2 and 3 were tested in two electrodes symmetrical capacitors. The optimized APBC sample holds the highest specific capacitance of 241.8 F/g, and the energy density of which is 5 times higher than that of PBC even at a current density of 5 A/g. This work presents a successful practice of preparing electrode material from environment-friendly biomass, bacterial cellulose. 展开更多
关键词 bacterial cellulose PYROLYSIS ACTIVATION SUPERCAPACITOR
原文传递
Interface engineering of snow-like Ru/RuO2 nanosheets for boosting hydrogen electrocatalysis 被引量:1
9
作者 Juntao Zhang Guomian Ren +7 位作者 Deyu Li Qingyu Kong Zhiwei Hu Yong Xu Suling Wang Lu Wang Maofeng Cao Xiaoqing Huang 《Science Bulletin》 SCIE EI CAS CSCD 2022年第20期2103-2111,M0004,共10页
Ru has recently been regarded as a promising catalyst for hydrogen oxidation reaction(HOR) and hydrogen evolution reaction(HER) due to its similar binding energy towards *H but lower price compared to Pt.Nevertheless,... Ru has recently been regarded as a promising catalyst for hydrogen oxidation reaction(HOR) and hydrogen evolution reaction(HER) due to its similar binding energy towards *H but lower price compared to Pt.Nevertheless, the quest of high-efficiency Ru-based catalysts for HOR and HER is driven by the current disadvantages including low activity and unsatisfactory stability. Herein, we have fabricated and engineered two-dimensional(2D) Ru-based snow-like nanosheets with Ru/Ru O2interface(Ru/Ru O2SNSs)via a post-annealing treatment. Detailed characterizations and theoretical calculations indicate that the interfacial synergy, which is dependent on the temperature for annealing, can alter the hydrogen binding energy(HBE) and hydroxide binding energy(OHBE), as a result of the enhanced HOR and HER performance. Impressively, the optimal Ru/RuO_(2) SNSs display a mass activity of 9.13 A mgRu^(–1) at an overpotential of 50 m V in 0.1 mol L^(–1) KOH for HOR, which is 65, 304, and 21 times higher than those of Ru SNSs(0.14 A mg_(Ru)^(–1)), RuO_(2) SNSs(0.03 A mg_(Ru)^(–1)), and commercial Pt/C(0.43 A mg_(Ru)^(–1)), respectively.Moreover, Ru/RuO_(2) SNSs display improved HER activity with a low overpotential of 20.2 m V for achieving10 m A cm^(-2)in 1 mol L^(–1)KOH. This work not only provides an efficient catalyst for HOR and HER, but also promotes fundamental research on the fabrication and modification of catalysts in heterogeneous catalysis. 展开更多
关键词 Interface engineering Snow-like Ru/RuO2 nanosheets Interfacial synergy Hydrogen oxidation reaction Hydrogen evolution reaction
原文传递
GaN-based LEDs for light communication 被引量:1
10
作者 LiXia Zhao ShiChao Zhu +4 位作者 ChunHui Wu Chao Yang ZhiGuo Yu Hua Yang Lei Liu 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS CSCD 2016年第10期1-10,共10页
Rapid improvement in the efficiency of GaN-based LEDs not only speed up its applications for general illumination, but offer the possibilities for data transmission. This review is to provide an overview of current pr... Rapid improvement in the efficiency of GaN-based LEDs not only speed up its applications for general illumination, but offer the possibilities for data transmission. This review is to provide an overview of current progresses of GaN-based LEDs for light communications. The modulation bandwidth of GaN-based LEDs has been first improved by optimizing the LED epilayer structures and the modulation bandwidth of 73 MHz was achieved at the driving current density of 40 A/cm2 by changing the multi-quantum well structures. After that, in order to increase the current density tolerance, different parallel flip-chip micro-LED arrays were fabricated. With a high injected current density of ~7900 A/cm2, a maximum modulation bandwidth of ~227 MHz was obtained with optical power greater than 30 mW. Besides the increase of carrier concentrations, the radiative recombination coefficient B was also enhanced by modifying the photon surrounding environment based on some novel nanostructures such as resonant cavity, surface plasmon, and photonic crystals. The optical 3 dB modulation bandwidth of GaN-based nanostructure LEDs with Ag nanoparticles was enhanced by 2 times compared with GaN-based nanostructure LEDs without Ag nanoparticles.Our results demonstrate that using the QW-SP coupling can effectively help to enhance the carrier spontaneous emission rate and also increase the modulation bandwidth for LEDs, especially for LEDs with high intrinsic IQE. In addition, we discuss the progress of the faster color conversion stimulated by GaN-based LEDs. 展开更多
关键词 GaN-based LEDs modulation bandwidth carrier concentration radiative recombination coefficient
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部