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为研究真空环境下电磁场诱发针-板电晕放电特性,研制了电磁场发生器、真空系统、高压静电源、动态电位测试仪等组成的电磁场辐照诱发真空电晕放电模拟试验系统。该系统可实现真空管内气压为80 Pa的低真空环境,并利用此系统进行在电磁场的作用下的电晕放电试验,初步得到了电磁场辐照诱发电晕放电的阈值电压的变化规律。试验结果表明:当温度、湿度等其他环境因素基本不变,真空管内气压为80 Pa时, 正常放电阈值为-590 V, 利用负极性高压静电放电, 电压取值范围10~20 kV, 产生的电磁脉冲辐射作用于真空管内充电区域,可使放电阈值降低90~180 V。 相似文献
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Structure phase transformation and equation of state of cerium metal under pressures up to 51 GPa 下载免费PDF全文
This study presents high pressure phase transitions and equation of states of cerium under pressures up to 51 GPa at room temperature. The angle-dispersive x-ray diffraction experiments are carried out using a high energy synchrotron x-ray source. The bulk moduli of high pressure phases of cerium are calculated using the Birch–Murnaghan equation. We discuss and correct several previous controversial conclusions, which are caused by the measurement accuracy or personal explanation. The c/a axial ratio of ε-Ce has a maximum value at about 29 GPa, i.e., c/a ≈ 1.690. 相似文献
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Effect of f-c hybridization on the $\gamma\to \alpha$ phase transition of cerium studied by lanthanum doping 下载免费PDF全文
Yong-Huan Wang 《中国物理 B》2022,31(8):87102-087102
The hybridization between the localized 4f level (f) with conduction (c) electrons in $\gamma $-Ce upon cooling has been previously revealed in single crystalline thin films experimentally and theoretically, whereas its influence on the $\gamma \to \alpha $ phase transition was not explicitly verified, due to the fact that the phase transition happened in the bulk-layer, leaving the surface in the $\gamma $ phase. Here in our work, we circumvent this issue by investigating the effect of alloying addition of La on Ce, by means of crystal structure, electronic transport and angle resolved photoemission spectroscopy measurements, together with a phenomenological periodic Anderson model and a modified Anderson impurity model. Our current researches indicate that the weakening of f-c hybridization is the major factor in the suppression of $\gamma \to \alpha $ phase transition by La doping. The consistency of our results with the effects of other rare earth and actinide alloying additions on the $\gamma \to \alpha $ phase transition of Ce is also discussed. Our work demonstrates the importance of the interaction between f and c electrons in understanding the unconventional phase transition in Ce, which is intuitive for further researches on other rare earth and actinide metals and alloys with similar phase transition behaviors. 相似文献
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