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Start Over Author "Jun Pu" Journal chinese physics b
7 results on '"Jun Pu"'

2. Congruent melting of tungsten phosphide at 5 GPa and 3200 °C for growing its large single crystals

Author

Xiang, Xiao-Jun, primary, Song, Guo-Zhu, additional, Zhou, Xue-Feng, additional, Liang, Hao, additional, Xu, Yue, additional, Qin, Shi-Jun, additional, Wang, Jun-Pu, additional, Hong, Fang, additional, Dai, Jian-Hong, additional, Zhou, Bo-Wen, additional, Liang, Wen-Jia, additional, Yin, Yun-Yu, additional, Zhao, Yu-Sheng, additional, Peng, Fang, additional, Yu, Xiao-Hui, additional, and Wang, Shan-Min, additional

Published
2020
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3. Congruent melting of tungsten phosphide at 5 GPa and 3200 °C for growing its large single crystals*

Author

Yue Xu, Shanmin Wang, Wenjia Liang, Hao Liang, Bowen Zhou, Fang Hong, Yunyu Yin, Shijun Qin, Jun-Pu Wang, Xuefeng Zhou, Xiaohui Yu, Fang Peng, Yusheng Zhao, Xiao-Jun Xiang, Jian-Hong Dai, and Guozhu Song

Subjects
Materials science, Phosphide, General Physics and Astronomy, chemistry.chemical_element, Crystal growth, 02 engineering and technology, Tungsten, 021001 nanoscience & nanotechnology, 01 natural sciences, Grain size, law.invention, Crystal, chemistry.chemical_compound, chemistry, Congruent melting, law, Chemical physics, 0103 physical sciences, Crystallization, 010306 general physics, 0210 nano-technology, Thermal analysis
Abstract

As one of important members of refractory materials, tungsten phosphide (WP) holds great potential for fundamental study and industrial applications in many fields of science and technology, due to its excellent properties such as superconductivity and as-predicted topological band structure. However, synthesis of high-quality WP crystals is still a challenge by using tradition synthetic methods, because the synthesis temperature for growing its large crystals is very stringently required to be as high as 3000 °C, which is far beyond the temperature capability of most laboratory-based devices for crystal growth. In addition, high temperature often induces the decomposition of metal phosphides, leading to off-stoichiometric samples based on which the materials’ intrinsic properties cannot be explored. In this work, we report a high-pressure synthesis of single-crystal WP through a direct crystallization from cooling the congruent W–P melts at 5 GPa and ∼ 3200 °C. In combination of x-ray diffraction, electron microscope, and thermal analysis, the crystal structure, morphology, and stability of recovered sample are well investigated. The final product is phase-pure and nearly stoichiometric WP in a single-crystal form with a large grain size, in excess of one millimeter, thus making it feasible to implement most experimental measurements, especially, for the case where a large crystal is required. Success in synthesis of high-quality WP crystals at high pressure can offer great opportunities for determining their intrinsic properties and also making more efforts to study the family of transition-metal phosphides.

Published
2020

6. Novel transit-time oscillator (TTO) combining advantages of radial-line and axial TTO.

Author

Wei-Li Xu, Jun-Tao He, Jun-Pu Ling, Li-Li Song, Bing-Fang Deng, Ouzhixiong Dai, and Xing-Jun Ge

Subjects
RELATIVISTIC electron beams, MAGNETIC fields, ELECTRIC fields, ENERGY storage, SOLENOIDS
Abstract

A novel transit-time oscillator (TTO) is proposed in this paper. An axial cathode which has been widely used in high power microwave (HPM) source and an extractor with radial feature are adopted. In this way, the inherent advantages of axial and radial TTO, both of which can be utilized as high-quality intense relativistic electron beam (IREB), can be generated and the power capacity is also increased. The working mode is π/2 mode of TM01 based on small-signal theory, and under the same energy storage, the maximum electric field in extractor decreases 16.3%. Besides, by utilizing the natural bending of the solenoid, this TTO saves over 60% of the length required by the uniform magnetic field, and consequently reduces the energy consumed by solenoid. The PIC simulation shows that by using 1.0-T decreasing magnetic field generated by the shorter solenoid, 3.37-GW microwave at 12.43 GHz is generated with 620-kV and 13.27-kA input, and the overall conversion efficiency is 41%. [ABSTRACT FROM AUTHOR]

Published
2019
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7. A Ku-band magnetically insulated transmission line oscillator with overmoded slow-wave-structure.

Author

Tao Jiang, Jun-Tao He, Jian-De Zhang, Zhi-Qiang Li, and Jun-Pu Ling

Subjects
ELECTRIC lines, SLOW wave structures, MICROWAVES, ELECTRIC oscillators, RESONANT states
Abstract

In order to enhance the power capacity, an improved Ku-band magnetically insulated transmission line oscillator (MILO) with overmoded slow-wave-structure (SWS) is proposed and investigated numerically and experimentally. The analysis of the dispersion relationship and the resonant curve of the cold test indicate that the device can operate at the near π mode of the TM01 mode, which is useful for mode selection and control. In the particle simulation, the improved Ku-band MILO generates a microwave with a power of 1.5 GW and a frequency of 12.3 GHz under an input voltage of 480 kV and input current of 42 kA. Finally, experimental investigation of the improved Ku-band MILO is carried out. A high-power microwave (HPM) with an average power of 800 MW, a frequency of 12.35 GHz, and pulse width of 35 ns is generated under a diode voltage of 500 kV and beam current of 43 kA. The consistency between the experimental and simulated far-field radiation pattern confirms that the operating mode of the improved Ku-band MILO is well controlled in π mode of the TM01 mode. [ABSTRACT FROM AUTHOR]

Published
2016
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