Guo Liu

University of Electronic Science and Technology of China

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Co-Authors

Jianxun Wang

Jilin University

Wei Jiang

University of Electronic Science and Technology of China

Yong Luo

University of Electronic Science and Technology of China

Yelei Yao

University of Electronic Science and Technology of China

Zewei Wu

University of Electronic Science and Technology of China

Youlei Pu

University of Electronic Science and Technology of China

Jianxun Wang

University of Electronic Science and Technology of China

Guoxiang Shu

Shenzhen University

Weijie Wang

University of Electronic Science and Technology of China

Yu Wang

University of Electronic Science and Technology of China

Cooperative Institutions

University of Electronic Science and Technology of China

153

Shenzhen University

Chinese Academy of Sciences

Laboratoire de Chimie

Sichuan University

University of Chinese Academy of Sciences

Shanghai Jiao Tong University

Zhejiang University

Tsinghua University

Jinan University

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Long Pulse and High Duty Operation of a W-Band Gyrotron Traveling Wave Tube

IEEE Electron Device Letters (2023)

Guo Liu Wei Jiang Yelei Yao Yu Wang Yingjian Cao

In this letter, we reported a gyrotron traveling wave tube (gyro-TWT) featured broadband and high power at the University Electronic Science and Technology of China (UESTC), which had achieved a long pulse width up to 2 ms and a maximum duty cycle of up to 40%. Two typical operation states, i.e. high voltage/current (60.5 kV/9.0 A) and low voltage/current (46 kV/2.6

$\sim $

2.9 A), are respectively hot tested for high pulse and average power. With a duty cycle of 40%, the measured maximum average power is up to 20.1 kW.

Gyrotron

Duty cycle

Traveling-wave tube

10.1109/led.2023.3255303

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Citations (11)

Suppression and Influence of Photovoltaic DC Field on Volume Hologram

Chinese Journal of Lasers (2003)

Guo Liu

A nonuniform photovoltaic field is created in Fe∶LiNbO 3 during hologram recording exposures. Experimental results and analysis show the degradation of the volume holograms in the presence of the photovoltaic field. A sodium chloride solution is used to short circuit the crystal to improve the stored images quality. 1000 holograms which can be reconstructed with high fidelity have been stored in a common volume of the crystal which was placed in the sodium chloride solution.

Crystal (programming language)

Volume hologram

Degradation

Source

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Citations (0)

Design and Measurement of a Terahertz High-Order Circular TE13 Mode Converter

Lecture notes in electrical engineering (2023)

Weijie Wang Yingjian Cao Guo Liu Yu Wang Guoxiang Shu

Port (circuit theory)

Reflection

10.1007/978-981-99-0416-7_73

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Citations (0)

Study of X-Ray Spectra Energy Distribution Excited by Spent Electrons in an X-Band Gyrotron Traveling Wave Tube

Yue Wang Guo Liu Wei Jiang Jianxun Wang Yong Luo

In this paper, theoretical and PIC simulation of the bremsstrahlung X-ray produced by an X-band gyrotron traveling tube (gyro-Twt)is analyzed with CST Particle Studio, which are used to investigate the X-ray spectra of the collector. X-rays flux spectral density and dose are obtained with theoretical Kramers law when the gyro-TWT operates with saturated output power of 136.9 kW at 9.6 GHz. Studying the X-ray spectra is of great importance for the X-ray protection of the gyro-TWT collector.

Gyrotron

Traveling-wave tube

Flux tube

X-ray tube

X band

10.1109/ivec.2019.8745144

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Citations (0)

Design and Measurement of a Nonlinear-Curve Directional Coupler for Sheet Beam Traveling Wave Tube

IEEE Transactions on Electron Devices (2016)

Liya Yang Jianxun Wang Guoxiang Shu Guo Liu E. Agurgo Balfour

A new type of input/output coupler for sheet beam traveling wave tube is designed, analyzed, and measured in this paper. In the design, a special sloped coupling aperture distributed between two paralleled rectangular waveguides in H-plane is employed for compact dimensions, ease of fabrication, attainment of high power capacity, and more convenience for periodic cusped magnet focusing system. A nonlinear-curve profile with Chebyshev-curve distribution is applied to extend the operating frequency bandwidth while suppressing reflections to avoid generating oscillation in the slow-wave structure. Based on the analytical investigation and numerical simulation, an optimized sloping angle of the coupling aperture is obtained to improved performance. Simulations imply that the coupler achieves a broadband bandwidth (S ₁₁ <; -20 dB) of 23 and 10 GHz in W- and Q-band, respectively, with coupling coefficient above -0.2 dB. Cold test results satisfactorily agree with simulations.

Traveling-wave tube

Aperture (computer memory)

Varicap

10.1109/ted.2016.2593663

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Citations (12)

Oligocene magmatism in the eastern margin of the east Himalayan syntaxis and its implication for the India-Asia post-collisional process

AGU Fall Meeting Abstracts (2012)

H. Zhang Fabin Pan Guo Liu Wenchao Xu Nancy R. Harris

Margin (machine learning)

Source

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Citations (0)

Evaluation of safety monitoring scheme for offshore floating platform based on the multiple connection numbers

E3S Web of Conferences (2023)

Guo Liu Qiyue Guo Yanqiang Bai

To accurately evaluate the safety monitoring scheme of offshore floating platform, a five-element connection number analysis method for evaluating the safety monitoring scheme of offshore floating platform was developed in this paper. According to the characteristics of safety monitoring of offshore floating platform, an index system was constructed. Considering the complexity and uncertainty in the evaluation of safety monitoring schemes, the Set Pair Analysis based on the five-element connection number was used to establish the similarity, difference and reverse evaluation model of safety monitoring schemes for offshore floating platforms. In addition, entropy weight method was employed to calculate the objective weights. Taking an offshore floating platform project in Guangdong, China as an example, a case study was carried out. The study showed that the evaluation grade of this monitoring program was good and the scientificity of the programming method is the most important influencing factor. The research results provided a theoretical basis for the safety monitoring scheme management of offshore floating platform.

Safety Monitoring

10.1051/e3sconf/202338502034

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Citations (0)

Quantitative assessment of corneal elasticity distribution after FS‐LASIK using optical coherence elastography

Journal of Biophotonics (2024)

Xiao Han Yubao Zhang Gang Shi Guo Liu Sizhu Ai

Abstract Quantifying corneal elasticity after femtosecond laser‐assisted in situ keratomileusis (FS‐LASIK) procedure plays an important role in improving surgical safety and quality, since some latent complications may occur ascribing to changes in postoperative corneal biomechanics. Nevertheless, it is suggested that current research has been severely constrained due to the lack of an accurate quantification method to obtain postoperative corneal elasticity distribution. In this paper, an acoustic radiation force optical coherence elastography system combined with the improved phase velocity algorithm was utilized to realize elasticity distribution images of the in vivo rabbit cornea after FS‐LASIK under various intraocular pressure levels. As a result, elasticity variations within and between the regions of interest could be identified precisely. This is the first time that elasticity imaging of in vivo cornea after FS‐LASIK surgery was demonstrated, and the results suggested that this technology may hold promise in further exploring corneal biomechanical properties after refractive surgery.

LASIK

Elasticity (physics)

Corneal Biomechanics

Refractive surgery

Corneal Thickness

Optical Coherence Tomography

Tissue Optical Clearing

Photoacoustic Imaging

Acoustic radiation force

10.1002/jbio.202300441

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Citations (4)

Design and verification of a backward wave oscillation suppression circuit for the Ka-band gyrotron travelling-wave tube

Review of Scientific Instruments (2023)

Yuan Ma Guo Liu Changbiao Lei Yingjian Cao Weijie Wang

Backward wave oscillation seriously degrades the stability of gyrotron travelling-wave tubes (gyro-TWTs), especially during high average/continuous wave operation. To solve this problem, a selective mode suppression structure (SMSS) based on the mode coupling principle is proposed and applied in the nonlinear beam-wave interaction region to suppress the parasitic TE11 mode. It is capable of obtaining a high power and improving the tube stability. Simulation results demonstrate that the SMSS can raise the starting current from 10 to 18 A and the starting pitch factor from 1.2 to 1.6. Based on this proposed circuit, a Ka-band TE01 mode gyro-TWT was designed, and the particle-in-cell simulation shows that it can achieve a saturated output power of over 150 kW from 29.7 to 31.7 GHz with a velocity spread of 2.2%. For verification, a SMSS is manufactured and cold tested. The measurement of S-parameters reveals that it can effectively suppress the parasitic TE11 mode.

Gyrotron

Oscillation (cell signaling)

Traveling-wave tube

Ka band

Mode (computer interface)

10.1063/5.0164265

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Citations (0)

Design and Measurement of a Broadband Beryllium Oxide Window With High Power Handling Capability

IEEE Transactions on Electron Devices (2021)

Guo Liu Yu Wang Weijie Wang Jianxun Wang Wei Jiang

A broadband dielectric window with high power handling capability for gyrotron traveling wave tubes (gyro-TWTs) had been designed based on the step-type impedance transition structure. The manufactured beryllium oxide (BeO) window can achieve a relative bandwidth of 35.3% with a maximum reflection of −20 dB in the

${X}$

-band, and the corresponding transmission loss is over −0.1 dB. The resonant spikes caused by engineering factors, including assembly tilt and gap, are investigated and analyzed. Thermal analysis shows that the BeO window can achieve a high average/CW power handling capability of over 232 kW within a wide frequency range. The fabricated input window has been successfully applied in our

${X}$

-band broadband and high-power gyro-TWT.

Gyrotron

Beryllium oxide

10.1109/ted.2021.3098252

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Citations (2)