期刊文献+
共找到4篇文章
< 1 >
每页显示 20 50 100
地球同步轨道附近哨声湍流对“种子电子”的加速 被引量:10
1
作者 李柳元 曹晋滨 周国成 《地球物理学报》 SCIE EI CAS CSCD 北大核心 2004年第5期756-761,共6页
本文在等离子体准线性理论下研究了地球同步轨道附近哨声湍流对亚暴“种子电子”的波 -电子共振相互作用 .当发生这种共振时 ,“种子电子”的动量分布函数经动量扩散而随时间演化 ,部分低能电子数减少了 ,而高能尾部分的相对论电子 (能... 本文在等离子体准线性理论下研究了地球同步轨道附近哨声湍流对亚暴“种子电子”的波 -电子共振相互作用 .当发生这种共振时 ,“种子电子”的动量分布函数经动量扩散而随时间演化 ,部分低能电子数减少了 ,而高能尾部分的相对论电子 (能量大于 1MeV)数增加了 ,说明“种子电子”得到了哨声湍流的有效加速 ,且哨声湍流的能量越高 ,其加速效率越高 .另外 ,哨声湍流的频率越低 (或波数越小 ) ,共振电子的能量越高 (或单位质量的动量越大 ) ;频率范围越宽 ,共振电子的能量范围越宽 ,被加速的电子数也越多 .磁层哨声湍流加速“种子电子”大约在 30h内就可以造成相对论电子数显著增加 ,这正好和大多数磁暴期间观测到的相对论电子通量的增长时间相当 . 展开更多
关键词 地球同步轨道 相对论电子 哨声湍流 波-电子共振
下载PDF
Temperature-Dependent Formation of Redox Sites in Molybdenum Trioxide Studied by Electron Paramagnetic Resonance Spectroscopy
2
作者 谭天 陈明 +1 位作者 苏吉虎 杜江峰 《Chinese Journal of Chemical Physics》 SCIE CAS CSCD 2019年第6期657-660,I0002,共5页
The formation and qualification of redox sites in transition metal oxides are always the active fields related to electronics, catalysis, sensors, and energy-storage units. In the present study, the temperature depend... The formation and qualification of redox sites in transition metal oxides are always the active fields related to electronics, catalysis, sensors, and energy-storage units. In the present study, the temperature dependence of thermal reduction of MoO3 was surveyed at the range of 350℃ to 750℃. Upon reduction, the formed redox species characterized by EPR spectroscopy are the MoVion and superoxide anion radical (O2-) when the reduction was induced at the optimal temperature of 300-350℃. When heating-up from 350℃, the EPR signals started to decline in amplitude. The signals in the range of 400-450℃ decreased to half of that at 350℃, and then to zero at ~600℃. Further treatment at even higher temperature or prolonged heating time at 500℃ caused more reduction and more free electrons were released to the MoO3 bulk, which results in a delocalized means similar to the antiferromagnetic coupling. These data herein are helpful to prepare and study the metal-oxide catalysts. 展开更多
关键词 MOO3 Thermal reduction Mo~Ⅴ Superoxide anion radical Electron paramagnetic resonance spectroscopy
下载PDF
Investigation on tunneling in optoelectronic devices with consideration of subwaves 被引量:1
3
作者 WANG XianPing YIN Cheng +2 位作者 SANG MingHuang DAI ManYuan CAO ZhuangQi 《Science China(Physics,Mechanics & Astronomy)》 SCIE EI CAS 2011年第3期388-392,共5页
Since novel optoelectronic devices based on the peculiar behaviors of the tunneling probability, e.g., resonant tunneling devices (RTD) and band-pass filter, are steadily proposed, the analytic transfer matrix (ATM) m... Since novel optoelectronic devices based on the peculiar behaviors of the tunneling probability, e.g., resonant tunneling devices (RTD) and band-pass filter, are steadily proposed, the analytic transfer matrix (ATM) method is extended to study these devices. For several examples, we explore the effect of the scattered subwaves on tunneling; it is shown that the resonant or band-pass structures in tunneling probability are determined by the phase shift results from the scattered subwaves. 展开更多
关键词 quantum tunneling WKB approximation the ATM method subwaves
原文传递
Management of electron paramagnetic resonance spectrometer in a university core laboratory
4
作者 Yingli Xu Guangcan Bai Jingfen Lu 《Journal of Chinese Pharmaceutical Sciences》 CAS CSCD 2019年第7期519-526,共8页
Electron Paramagnetic Resonance(EPR)is the only spectral method for direct detection of paramagnetic substances.EPR technology can be used for the qualitative and quantitative analysis of free radicals and transition ... Electron Paramagnetic Resonance(EPR)is the only spectral method for direct detection of paramagnetic substances.EPR technology can be used for the qualitative and quantitative analysis of free radicals and transition metals in solid,liquid,gas,cell and living samples.It is widely used in chemistry,material science,life science,quantum physics and other researches.This report discusses the basic principle,instrument structure,common problem solving,daily maintenance,and management model of the electron paramagnetic resonance spectrometer(German Bruker A-200)in the State Key Laboratory of Natural and Biomimetic Drugs of Peking University Health Science Center,so that the instrument can be fully used for various scientific researches. 展开更多
关键词 Electron paramagnetic resonance spectrometer Operational attention problem Instrument maintenance
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部